2024-03-29T10:59:04Zhttp://repository.helmholtz-hzi.de/oai/requestoai:repository.helmholtz-hzi.de:10033/3386212019-08-30T11:26:13Zcom_10033_620533col_10033_620534
Influence of fenofibrate treatment on triacylglycerides, diacylglycerides and fatty acids in fructose fed rats.
Kopf, Thomas
Schaefer, Hans-Ludwig
Troetzmueller, Martin
Koefeler, Harald
Broenstrup, Mark
Konovalova, Tatiana
Schmitz, Gerd
Fenofibrate (FF) lowers plasma triglycerides via PPARα activation. Here, we analyzed lipidomic changes upon FF treatment of fructose fed rats. Three groups with 6 animals each were defined as control, fructose-fed and fructose-fed/FF treated. Male Wistar Unilever Rats were subjected to 10% fructose-feeding for 20 days. On day 14, fenofibrate treatment (100 mg/kg p.o.) was initiated and maintained for 7 days. Lipid species in serum were analyzed using mass spectrometry (ESI-MS/MS; LC-FT-MS, GC-MS) on days 0, 14 and 20 in all three groups. In addition, lipid levels in liver and intestine were determined. Short-chain TAGs increased in serum and liver upon fructose-feeding, while almost all TAG-species decreased under FF treatment. Long-chain unsaturated DAG-levels (36:1, 36:2, 36:4, 38:3, 38:4, 38:5) increased upon FF treatment in rat liver and decreased in rat serum. FAs, especially short-chain FAs (12:0, 14:0, 16:0) increased during fructose-challenge. VLDL secretion increased upon fructose-feeding and together with FA-levels decreased to control levels during FF treatment. Fructose challenge of de novo fatty acid synthesis through fatty acid synthase (FAS) may enhance the release of FAs ≤ 16:0 chain length, a process reversed by FF-mediated PPARα-activation.
2015-01-22
2015-01-22
2014
Article
Influence of fenofibrate treatment on triacylglycerides, diacylglycerides and fatty acids in fructose fed rats. 2014, 9 (9):e106849 PLoS ONE
1932-6203
25198467
10.1371/journal.pone.0106849
http://hdl.handle.net/10033/338621
PloS one
en
oai:repository.helmholtz-hzi.de:10033/3443782019-08-30T11:26:13Zcom_10033_620533col_10033_620534
Antiviral drug discovery: broad-spectrum drugs from nature.
Martinez, J P
Sasse, F
Brönstrup, M
Diez, J
Meyerhans, A
Helmholtz Centre for infection research (HZI), Inhoffenstr. 7, 38124 Braunschweig, Germany.
Covering: up to April 2014. The development of drugs with broad-spectrum antiviral activities is a long pursued goal in drug discovery. It has been shown that blocking co-opted host-factors abrogates the replication of many viruses, yet the development of such host-targeting drugs has been met with scepticism mainly due to toxicity issues and poor translation to in vivo models. With the advent of new and more powerful screening assays and prediction tools, the idea of a drug that can efficiently treat a wide range of viral infections by blocking specific host functions has re-bloomed. Here we critically review the state-of-the-art in broad-spectrum antiviral drug discovery. We discuss putative targets and treatment strategies, with particular focus on natural products as promising starting points for antiviral lead development.
2015-02-11
2015-02-11
2015-01
Article
Antiviral drug discovery: broad-spectrum drugs from nature. 2015, 32 (1):29-48 Nat Prod Rep
1460-4752
25315648
10.1039/c4np00085d
http://hdl.handle.net/10033/344378
Natural product reports
en
oai:repository.helmholtz-hzi.de:10033/3464652019-08-30T11:37:00Zcom_10033_620533col_10033_620534
Phenotypic plasticity in a willow leaf beetle depends on host plant species: release and recognition of beetle odors.
Austel, Nadine
Reinecke, Andreas
Björkman, Christer
Hilker, Monika
Meiners, Torsten
Helmholtz-Centre for Infection Research, Inhoffen-Str. 7, Department of Chemical Biology, 38124 Braunschweig, Germany.
Aggregation behavior of herbivorous insects is mediated by a wide range of biotic and abiotic factors. It has been suggested that aggregation behavior of the blue willow leaf beetle Phratora vulgatissima is mediated by both host plant odor and by odor released by the beetles. Previous studies show that the beetles respond to plant odors according to their prior host plant experiences. Here, we analyzed the effect of the host plant species on odor released and perceived by adult P. vulgatissima. The major difference between the odor of beetles feeding on salicin-rich and salicin-poor host plants was the presence of salicylaldehyde in the odor of the former, where both males and females released this compound. Electrophysiological studies showed that the intensity of responses to single components of odor released by beetles was sex specific and dependent on the host plant species with which the beetles were fed. Finally, behavioral studies revealed that males feeding on salicin-rich willows were attracted by salicylaldehyde, whereas females did not respond behaviorally to this compound, despite showing clear antennal responses to it. Finally, the ecological relevance of the influence of a host plant species on the plasticity of beetle odor chemistry, perception, and behavior is discussed.
2015-03-10
2015-03-10
2015-02
Article
Phenotypic plasticity in a willow leaf beetle depends on host plant species: release and recognition of beetle odors. 2015, 40 (2):109-24 Chem. Senses
1464-3553
25537016
10.1093/chemse/bju065
http://hdl.handle.net/10033/346465
Chemical senses
en
oai:repository.helmholtz-hzi.de:10033/3642602019-08-30T11:34:48Zcom_10033_620533col_10033_620534
Cytotoxic and antivascular 1-methyl-4-(3-fluoro-4-methoxyphenyl)-5-(halophenyl)-imidazoles.
Biersack, Bernhard
Muthukumar, Yazh
Schobert, Rainer
Sasse, Florenz
A series of 1-methyl-4,5-diphenylimidazoles 6 with various patterns of m-halogen substitution at the 5-phenyl ring were tested for cytotoxicity in cancer and nonmalignant cell lines and for their capacity to prevent tube formation in HUVEC cultures. Unlike the monofluoro and difluoro derivatives 6a and 6e, the monobromo and diiodo analogs 6c and 6h were strongly cytotoxic and inhibited the polymerization of tubulin and the tube formation by HUVEC. The dibromo derivative 6g displayed a unique selectivity for KB-3-1 cervix and PC-3 prostate cancer cells. It also inhibited the tube formation by HUVEC and the polymerization of tubulin which is indicative of its potential antiangiogenic activity in solid tumors.
2015-04-09
2015-04-09
2011-11-01
Article
Cytotoxic and antivascular 1-methyl-4-(3-fluoro-4-methoxyphenyl)-5-(halophenyl)-imidazoles. 2011, 21 (21):6270-3 Bioorg. Med. Chem. Lett.
1464-3405
21963303
10.1016/j.bmcl.2011.09.005
http://hdl.handle.net/10033/364260
Bioorganic & medicinal chemistry letters
en
oai:repository.helmholtz-hzi.de:10033/6208452018-06-13T00:05:03Zcom_10033_620533col_10033_620534
Myxobacteria: natural pharmaceutical factories
Diez, Juana
Martinez, Javier P
Mestres, Jordi
Sasse, Florenz
Frank, Ronald
Meyerhans, Andreas
Helmholtz Centre for infection research, Ihoffenstr. 7, 38124 Braunschweig, Germany.
Abstract Myxobacteria are amongst the top producers of natural products. The diversity and unique structural properties of their secondary metabolites is what make these social microbes highly attractive for drug discovery. Screening of products derived from these bacteria has revealed a puzzling amount of hits against infectious and non-infectious human diseases. Preying mainly on other bacteria and fungi, why would these ancient hunters manufacture compounds beneficial for us? The answer may be the targeting of shared processes and structural features conserved throughout evolution.
2017-03-06
2017-03-06
2012-04-30
2015-09-04
Article
Microbial Cell Factories. 2012 Apr 30;11(1):52
http://dx.doi.org/10.1186/1475-2859-11-52
http://hdl.handle.net/10033/620845
en
Diez et al.; licensee BioMed Central Ltd.
oai:repository.helmholtz-hzi.de:10033/6207812018-06-12T18:07:03Zcom_10033_620533col_10033_620534
Elevated expression of VEGFR-3 in lymphatic endothelial cells from lymphangiomas
Norgall, Susanne
Papoutsi, Maria
Rössler, Jochen
Schweigerer, Lothar
Wilting, Jörg
Weich, Herbert A
Abstract Background Lymphangiomas are neoplasias of childhood. Their etiology is unknown and a causal therapy does not exist. The recent discovery of highly specific markers for lymphatic endothelial cells (LECs) has permitted their isolation and characterization, but expression levels and stability of molecular markers on LECs from healthy and lymphangioma tissues have not been studied yet. We addressed this problem by profiling LECs from normal dermis and two children suffering from lymphangioma, and also compared them with blood endothelial cells (BECs) from umbilical vein, aorta and myometrial microvessels. Methods Lymphangioma tissue samples were obtained from two young patients suffering from lymphangioma in the axillary and upper arm region. Initially isolated with anti-CD31 (PECAM-1) antibodies, the cells were separated by FACS sorting and magnetic beads using anti-podoplanin and/or LYVE-1 antibodies. Characterization was performed by FACS analysis, immunofluorescence staining, ELISA and micro-array gene analysis. Results LECs from foreskin and lymphangioma had an almost identical pattern of lymphendothelial markers such as podoplanin, Prox1, reelin, cMaf and integrin-α1 and -α9. However, LYVE-1 was down-regulated and VEGFR-2 and R-3 were up-regulated in lymphangiomas. Prox1 was constantly expressed in LECs but not in any of the BECs. Conclusion LECs from different sources express slightly variable molecular markers, but can always be distinguished from BECs by their Prox1 expression. High levels of VEGFR-3 and -2 seem to contribute to the etiology of lymphangiomas.
2017-01-27
2017-01-27
2007-06-21
2015-09-04
Journal Article
BMC Cancer. 2007 Jun 21;7(1):105
http://dx.doi.org/10.1186/1471-2407-7-105
http://hdl.handle.net/10033/620781
en
Norgall et al.
oai:repository.helmholtz-hzi.de:10033/6207632019-08-30T11:28:23Zcom_10033_620533col_10033_620534
The full-ORF clone resource of the German cDNA Consortium
Bechtel, Stephanie
Rosenfelder, Heiko
Duda, Anny
Peter Schmidt, Christian
Ernst, Ute
Wellenreuther, Ruth
Mehrle, Alexander
Schuster, Claudia
Bahr, Andre
Blöcker, Helmut
Heubner, Dagmar
Hoerlein, Andreas
Michel, Guenter
Wedler, Holger
Köhrer, Karl
Ottenwälder, Birgit
Poustka, Annemarie
Wiemann, Stefan
Schupp, Ingo
Abstract Background With the completion of the human genome sequence the functional analysis and characterization of the encoded proteins has become the next urging challenge in the post-genome era. The lack of comprehensive ORFeome resources has thus far hampered systematic applications by protein gain-of-function analysis. Gene and ORF coverage with full-length ORF clones thus needs to be extended. In combination with a unique and versatile cloning system, these will provide the tools for genome-wide systematic functional analyses, to achieve a deeper insight into complex biological processes. Results Here we describe the generation of a full-ORF clone resource of human genes applying the Gateway cloning technology (Invitrogen). A pipeline for efficient cloning and sequencing was developed and a sample tracking database was implemented to streamline the clone production process targeting more than 2,200 different ORFs. In addition, a robust cloning strategy was established, permitting the simultaneous generation of two clone variants that contain a particular ORF with as well as without a stop codon by the implementation of only one additional working step into the cloning procedure. Up to 92 % of the targeted ORFs were successfully amplified by PCR and more than 93 % of the amplicons successfully cloned. Conclusion The German cDNA Consortium ORFeome resource currently consists of more than 3,800 sequence-verified entry clones representing ORFs, cloned with and without stop codon, for about 1,700 different gene loci. 177 splice variants were cloned representing 121 of these genes. The entry clones have been used to generate over 5,000 different expression constructs, providing the basis for functional profiling applications. As a member of the recently formed international ORFeome collaboration we substantially contribute to generating and providing a whole genome human ORFeome collection in a unique cloning system that is made freely available in the community.
2017-01-27
2017-01-27
2007-10-31
2015-09-04
Journal Article
BMC Genomics. 2007 Oct 31;8(1):399
http://dx.doi.org/10.1186/1471-2164-8-399
http://hdl.handle.net/10033/620763
en
Bechtel et al.
oai:repository.helmholtz-hzi.de:10033/6207622018-06-12T22:36:04Zcom_10033_620533col_10033_620534
Mouse lung contains endothelial progenitors with high capacity to form blood and lymphatic vessels
Schniedermann, Judith
Rennecke, Moritz
Buttler, Kerstin
Richter, Georg
Städtler, Anna-Maria
Norgall, Susanne
Badar, Muhammad
Barleon, Bernhard
May, Tobias
Wilting, Jörg
Weich, Herbert A
Abstract Background Postnatal endothelial progenitor cells (EPCs) have been successfully isolated from whole bone marrow, blood and the walls of conduit vessels. They can, therefore, be classified into circulating and resident progenitor cells. The differentiation capacity of resident lung endothelial progenitor cells from mouse has not been evaluated. Results In an attempt to isolate differentiated mature endothelial cells from mouse lung we found that the lung contains EPCs with a high vasculogenic capacity and capability of de novo vasculogenesis for blood and lymph vessels. Mouse lung microvascular endothelial cells (MLMVECs) were isolated by selection of CD31+ cells. Whereas the majority of the CD31+ cells did not divide, some scattered cells started to proliferate giving rise to large colonies (> 3000 cells/colony). These highly dividing cells possess the capacity to integrate into various types of vessels including blood and lymph vessels unveiling the existence of local microvascular endothelial progenitor cells (LMEPCs) in adult mouse lung. EPCs could be amplified > passage 30 and still expressed panendothelial markers as well as the progenitor cell antigens, but not antigens for immune cells and hematopoietic stem cells. A high percentage of these cells are also positive for Lyve1, Prox1, podoplanin and VEGFR-3 indicating that a considerabe fraction of the cells are committed to develop lymphatic endothelium. Clonogenic highly proliferating cells from limiting dilution assays were also bipotent. Combined in vitro and in vivo spheroid and matrigel assays revealed that these EPCs exhibit vasculogenic capacity by forming functional blood and lymph vessels. Conclusion The lung contains large numbers of EPCs that display commitment for both types of vessels, suggesting that lung blood and lymphatic endothelial cells are derived from a single progenitor cell.
2017-01-27
2017-01-27
2010-07-01
2015-09-04
Journal Article
BMC Cell Biology. 2010 Jul 01;11(1):50
http://dx.doi.org/10.1186/1471-2121-11-50
http://hdl.handle.net/10033/620762
en
Schniedermann et al.
oai:repository.helmholtz-hzi.de:10033/6207022019-08-30T11:37:00Zcom_10033_620533col_10033_620534
Identification of myxobacteria-derived HIV inhibitors by a high-throughput two-step infectivity assay
Martinez, Javier P
Hinkelmann, Bettina
Fleta-Soriano, Eric
Steinmetz, Heinrich
Jansen, Rolf
Diez, Juana
Frank, Ronald
Sasse, Florenz
Meyerhans, Andreas
Abstract Background Drug-resistance and therapy failure due to drug-drug interactions are the main challenges in current treatment against Human Immunodeficiency Virus (HIV) infection. As such, there is a continuous need for the development of new and more potent anti-HIV drugs. Here we established a high-throughput screen based on the highly permissive TZM-bl cell line to identify novel HIV inhibitors. The assay allows discriminating compounds acting on early and/or late steps of the HIV replication cycle. Results The platform was used to screen a unique library of secondary metabolites derived from myxobacteria. Several hits with good anti-HIV profiles were identified. Five of the initial hits were tested for their antiviral potency. Four myxobacterial compounds, sulfangolid C, soraphen F, epothilon D and spirangien B, showed EC50 values in the nM range with SI > 15. Interestingly, we found a high amount of overlapping hits compared with a previous screen for Hepatitis C Virus (HCV) using the same library. Conclusion The unique structures and mode-of-actions of these natural compounds make myxobacteria an attractive source of chemicals for the development of broad-spectrum antivirals. Further biological and structural studies of our initial hits might help recognize smaller drug-like derivatives that in turn could be synthesized and further optimized.
2017-01-16
2017-01-16
2013-09-24
2015-09-04
Journal Article
Microbial Cell Factories. 2013 Sep 24;12(1):85
http://dx.doi.org/10.1186/1475-2859-12-85
http://hdl.handle.net/10033/620702
en
Martinez et al.; licensee BioMed Central Ltd.
oai:repository.helmholtz-hzi.de:10033/6206842019-08-30T11:35:39Zcom_10033_620533col_10033_620534
The myxobacterial metabolite ratjadone A inhibits HIV infection by blocking the Rev/CRM1-mediated nuclear export pathway
Fleta-Soriano, Eric
Martinez, Javier P
Hinkelmann, Bettina
Gerth, Klaus
Washausen, Peter
Diez, Juana
Frank, Ronald
Sasse, Florenz
Meyerhans, Andreas
Abstract Background The nuclear export of unspliced and partially spliced HIV-1 mRNA is mediated by the recognition of a leucine-rich nuclear export signal (NES) in the HIV Rev protein by the host protein CRM1/Exportin1. This makes the CRM1-Rev complex an attractive target for the development of new antiviral drugs. Here we tested the anti-HIV efficacy of ratjadone A, a CRM1 inhibitor derived from myxobacteria. Results Ratjadone A inhibits HIV infection in vitro in a dose-dependent manner with EC50 values at the nanomolar range. The inhibitory effect of ratjadone A occurs around 12 hours post-infection and is specific for the Rev/CRM1-mediated nuclear export pathway. By using a drug affinity responsive target stability (DARTS) assay we could demonstrate that ratjadone A interferes with the formation of the CRM1-Rev-NES complex by binding to CRM1 but not to Rev. Conclusion Ratjadone A exhibits strong anti-HIV activity but low selectivity due to toxic effects. Although this limits its potential use as a therapeutic drug, further studies with derivatives of ratjadones might help to overcome these difficulties in the future.
2017-01-06
2017-01-06
2014-01-29
2015-09-04
Journal Article
Microbial Cell Factories. 2014 Jan 29;13(1):17
http://dx.doi.org/10.1186/1475-2859-13-17
http://hdl.handle.net/10033/620684
en
Fleta-Soriano et al.; licensee BioMed Central Ltd.
oai:repository.helmholtz-hzi.de:10033/5775292019-08-30T11:34:48Zcom_10033_620533col_10033_620534
Soraphen A: A broad-spectrum antiviral natural product with potent anti-hepatitis C virus activity.
Koutsoudakis, George
Romero-Brey, Inés
Berger, Carola
Pérez-Vilaró, Gemma
Monteiro Perin, Paula
Vondran, Florian Wolfgang Rudolf
Kalesse, Markus
Harmrolfs, Kirsten
Müller, Rolf
Martinez, Javier P
Pietschmann, Thomas
Bartenschlager, Ralf
Brönstrup, Mark
Meyerhans, Andreas
Díez, Juana
TWINCORE, Centre for Experimental and Clinical Infection Research, Feodor-Lynen Str. 7, 30625, Hannover, Germany.
Soraphen A (SorA) is a myxobacterial metabolite that inhibits the acetyl-CoA carboxylase, a key enzyme in lipid biosynthesis. We have previously identified SorA to efficiently inhibit the human immunodeficiency virus (HIV). The aim of the present study was to evaluate the capacity of SorA and analogues to inhibit hepatitis C virus (HCV) infection.
2015-09-18
2015-09-18
2015-06-10
Article
Soraphen A: A broad-spectrum antiviral natural product with potent anti-hepatitis C virus activity. 2015: J. Hepatol.
1600-0641
26070407
10.1016/j.jhep.2015.06.002
http://hdl.handle.net/10033/577529
Journal of hepatology
oai:repository.helmholtz-hzi.de:10033/5794922019-08-30T11:32:41Zcom_10033_620533col_10033_620534
High-throughput screening and whole genome sequencing identifies an antimicrobially active inhibitor of Vibrio cholerae.
Sergeev, Galina
Roy, Sambit
Jarek, Michael
Zapolskii, Viktor
Kaufmann, Dieter E
Nandy, Ranjan K
Tegge, Werner
Pathogenic serotypes of Vibrio cholerae cause the life-threatening diarrheal disease cholera. The increasing development of bacterial resistances against the known antibiotics necessitates the search for new antimicrobial compounds and targets for this pathogen.
2015-10-08
2015-10-08
2014
Article
High-throughput screening and whole genome sequencing identifies an antimicrobially active inhibitor of Vibrio cholerae. 2014, 14:49 BMC Microbiol.
1471-2180
24568688
10.1186/1471-2180-14-49
http://hdl.handle.net/10033/579492
BMC microbiology
en
oai:repository.helmholtz-hzi.de:10033/5954332019-08-30T11:33:57Zcom_10033_620533col_10033_620534
Myxobacteria: natural pharmaceutical factories.
Diez, Juana
Martinez, Javier P
Mestres, Jordi
Sasse, Florenz
Frank, Ronald
Meyerhans, Andreas
Helmholtz Centre for infection research, Inhoffenstr. 7, D-38124 Braunschweig, Germany.
Myxobacteria are amongst the top producers of natural products. The diversity and unique structural properties of their secondary metabolites is what make these social microbes highly attractive for drug discovery. Screening of products derived from these bacteria has revealed a puzzling amount of hits against infectious and non-infectious human diseases. Preying mainly on other bacteria and fungi, why would these ancient hunters manufacture compounds beneficial for us? The answer may be the targeting of shared processes and structural features conserved throughout evolution.
2016-02-02
2016-02-02
2012
Article
Myxobacteria: natural pharmaceutical factories. 2012, 11:52 Microb. Cell Fact.
1475-2859
22545867
10.1186/1475-2859-11-52
http://hdl.handle.net/10033/595433
Microbial cell factories
en
eu-repo/grantAgreement/EC/FP7/261466
openAccess
oai:repository.helmholtz-hzi.de:10033/5959162019-08-30T11:28:23Zcom_10033_620533col_10033_620534
Integration of CD45-positive leukocytes into newly forming lymphatics of adult mice.
Buttler, K
Lohrberg, M
Gross, G
Weich, H A
Wilting, J
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
The embryonic origin of lymphatic endothelial cells (LECs) has been a matter of controversy since more than a century. However, recent studies in mice have supported the concept that embryonic lymphangiogenesis is a complex process consisting of growth of lymphatics from specific venous segments as well as the integration of lymphangioblasts into the lymphatic networks. Similarly, the mechanisms of adult lymphangiogenesis are poorly understood and have rarely been studied. We have recently shown that endothelial progenitor cells isolated from the lung of adult mice have the capacity to form both blood vessels and lymphatics when grafted with Matrigel plugs into the skin of syngeneic mice. Here, we followed up on these experiments and studied the behavior of host leukocytes during lymphangiogenesis in the Matrigel plugs. We observed a striking co-localization of CD45(+) leukocytes with the developing lymphatics. Numerous CD45(+) cells expressed the LEC marker podoplanin and were obviously integrated into the lining of lymphatic capillaries. This indicates that, similar to inflammation-induced lymphangiogenesis in man, circulating CD45(+) cells of adult mice are capable of initiating lymphangiogenesis and of adopting a lymphvasculogenic cellular differentiation program. The data are discussed in the context of embryonic and inflammation-induced lymphangiogenesis.
2016-02-09
2016-02-09
2016-01-09
Article
Integration of CD45-positive leukocytes into newly forming lymphatics of adult mice. 2016: Histochem. Cell Biol.
1432-119X
26748643
10.1007/s00418-015-1399-y
http://hdl.handle.net/10033/595916
Histochemistry and cell biology
oai:repository.helmholtz-hzi.de:10033/6133292019-08-30T11:33:26Zcom_10033_620533col_10033_620534
Reinvestigation of the Nitration of Trichloroethene - Subsequent Reactions of the Products and Evaluation of Their Antimicrobial and Antifungal Activity
Zapol'skii, Viktor A.
Namyslo, Jan C.
Sergeev, Galina
Brönstrup, Mark
Gjikaj, Mimoza
Kaufmann, Dieter E.
2016-06-16
2016-06-16
2015-12
Article
Reinvestigation of the Nitration of Trichloroethene - Subsequent Reactions of the Products and Evaluation of Their Antimicrobial and Antifungal Activity 2015, 2015 (35):7763 European Journal of Organic Chemistry
1434193X
10.1002/ejoc.201501066
http://hdl.handle.net/10033/613329
European Journal of Organic Chemistry
http://doi.wiley.com/10.1002/ejoc.201501066
oai:repository.helmholtz-hzi.de:10033/6154642019-08-30T11:26:13Zcom_10033_620533col_10033_620534
What Makes Umbilical Cord Tissue-Derived Mesenchymal Stromal Cells Superior Immunomodulators When Compared to Bone Marrow Derived Mesenchymal Stromal Cells?
Bárcia, R N
Santos, J M
Filipe, M
Teixeira, M
Martins, J P
Almeida, J
Água-Doce, A
Almeida, S C P
Varela, A
Pohl, S
Dittmar, K E J
Calado, S
Simões, S I
Gaspar, M M
Cruz, M E M
Lindenmaier, W
Graça, L
Cruz, H
Cruz, P E
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
MSCs derived from the umbilical cord tissue, termed UCX, were investigated for their immunomodulatory properties and compared to bone marrow-derived MSCs (BM-MSCs), the gold-standard in immunotherapy. Immunogenicity and immunosuppression were assessed by mixed lymphocyte reactions, suppression of lymphocyte proliferation and induction of regulatory T cells. Results showed that UCX were less immunogenic and showed higher immunosuppression activity than BM-MSCs. Further, UCX did not need prior activation or priming to exert their immunomodulatory effects. This was further corroborated in vivo in a model of acute inflammation. To elucidate the potency differences observed between UCX and BM-MSCs, gene expression related to immune modulation was analysed in both cell types. Several gene expression profile differences were found between UCX and BM-MSCs, namely decreased expression of HLA-DRA, HO-1, IGFBP1, 4 and 6, ILR1, IL6R and PTGES and increased expression of CD200, CD273, CD274, IL1B, IL-8, LIF and TGFB2. The latter were confirmed at the protein expression level. Overall, these results show that UCX seem to be naturally more potent immunosuppressors and less immunogenic than BM-MSCs. We propose that these differences may be due to increased levels of immunomodulatory surface proteins such as CD200, CD273, CD274 and cytokines such as IL1β, IL-8, LIF and TGFβ2.
2016-07-04
2016-07-04
2015
Article
What Makes Umbilical Cord Tissue-Derived Mesenchymal Stromal Cells Superior Immunomodulators When Compared to Bone Marrow Derived Mesenchymal Stromal Cells? 2015, 2015:583984 Stem Cells Int
1687-966X
26064137
10.1155/2015/583984
http://hdl.handle.net/10033/615464
Stem cells international
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6186722019-08-30T11:30:32Zcom_10033_620533col_10033_620534
Evaluation of the inflammatory potential of implant materials in a mouse model by bioluminescent imaging of intravenously injected bone marrow cells.
Rais, Bushra
Köster, Mario
Rahim, Muhammad Imran
Pils, Marina
Seitz, Jan-Marten
Hauser, Hansjörg
Wirth, Dagmar
Mueller, Peter P
Helmholtz Centre for infection research, Inhoffenstr. 7,38124 Braunschweig, Germany.
To evaluate the inflammatory potential of implants a bioluminescent imaging assay was developed using luciferase-expressing bone marrow cells that were injected into the blood circulation of wild-type mice. After subcutaneous implantation of titanium discs as an example for a clinically established biocompatible material, the luminosity was modest. Similarly, low luminosity signals were generated by pure magnesium implants that were used to represent metallic alloys that are presently under investigation as novel degradable implant materials. Increased luminosity was observed in response to degradable polymeric PLGA implants. Surgical wounds induced a basic luminescent response even in the absence of an implant. However, the material-independent response to injury could be minimized using injectable microparticle suspensions. In parallel with the resorption of biodegradable microparticles, the signal induced by PLGA declined faster when compared to non-degradable polystyrene suspensions. By using an interferon type I inducible Mx2 promoter construct to drive luciferase gene expression, the highest luminosity was observed in response to bacteria, indicating that the system could also be employed to monitor implant infections. Overall, labeled bone marrow cells yielded specific, well-defined localized signals that correlated with the inflammatory responses to implants. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2149-2158, 2016.
2016-08-23
2016-08-23
2016-09
Article
Evaluation of the inflammatory potential of implant materials in a mouse model by bioluminescent imaging of intravenously injected bone marrow cells. 2016, 104 (9):2149-58 J Biomed Mater Res A
1552-4965
27102724
10.1002/jbm.a.35758
http://hdl.handle.net/10033/618672
Journal of biomedical materials research. Part A
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6187302019-08-30T11:33:57Zcom_10033_620533col_10033_620534
Screening and characterization of molecules that modulate the biological activity of IFNs-I.
Bürgi, Milagros
Zapol'skii, Viktor A
Hinkelmann, Bettina
Köster, Mario
Kaufmann, Dieter E
Sasse, Florenz
Hauser, Hansjörg
Etcheverrigaray, Marina
Kratje, Ricardo
Bollati-Fogolín, Mariela
Oggero, Marcos
Helmholtz Centre for infection research, Inhoffenstr. 7,38124 Braunschweig, Germany.
Type I Interferons (IFNs-I) are species-specific glycoproteins which play an important role as primary defence against viral infections and that can also modulate the adaptive immune system. In some autoimmune diseases, interferons (IFNs) are over-produced. IFNs are widely used as biopharmaceuticals for a variety of cancer indications, chronic viral diseases, and for their immuno-modulatory action in patients with multiple sclerosis; therefore, increasing their therapeutic efficiency and decreasing their side effects is of high clinical value. In this sense, it is interesting to find molecules that can modulate the activity of IFNs. In order to achieve that, it was necessary to establish a simple, fast and robust assay to analyze numerous compounds simultaneously. We developed four reporter gene assays (RGAs) to identify IFN activity modulator compounds by using WISH-Mx2/EGFP, HeLa-Mx2/EGFP, A549-Mx2/EGFP, and HEp2-Mx2/EGFP reporter cell lines (RCLs). All of them present a Z' factor higher than 0.7. By using these RGAs, natural and synthetic compounds were analyzed simultaneously. A total of 442 compounds were studied by the Low Throughput Screening (LTS) assay using the four RCLs to discriminate between their inhibitory or enhancing effects on IFN activity. Some of them were characterized and 15 leads were identified. Finally, one promising candidate with enhancing effect on IFN-α/-β activity and five compounds with inhibitory effect were described.
2016-08-24
2016-08-24
2016-09-10
Article
Screening and characterization of molecules that modulate the biological activity of IFNs-I. 2016, 233:6-16 J. Biotechnol.
1873-4863
27346232
10.1016/j.jbiotec.2016.06.021
http://hdl.handle.net/10033/618730
Journal of biotechnology
en
http://creativecommons.org/licenses/by-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6205552019-08-30T11:26:13Zcom_10033_620533col_10033_620534
New Structural Templates for Clinically Validated and Novel Targets in Antimicrobial Drug Research and Development.
Klahn, Philipp
Brönstrup, Mark
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
The development of bacterial resistance against current antibiotic drugs necessitates a continuous renewal of the arsenal of efficacious drugs. This imperative has not been met by the output of antibiotic research and development of the past decades for various reasons, including the declining efforts of large pharma companies in this area. Moreover, the majority of novel antibiotics are chemical derivatives of existing structures that represent mostly step innovations, implying that the available chemical space may be exhausted. This review negates this impression by showcasing recent achievements in lead finding and optimization of antibiotics that have novel or unexplored chemical structures. Not surprisingly, many of the novel structural templates like teixobactins, lysocin, griselimycin, or the albicidin/cystobactamid pair were discovered from natural sources. Additional compounds were obtained from the screening of synthetic libraries and chemical synthesis, including the gyrase-inhibiting NTBI's and spiropyrimidinetrione, the tarocin and targocil inhibitors of wall teichoic acid synthesis, or the boronates and diazabicyclo[3.2.1]octane as novel β-lactamase inhibitors. A motif that is common to most clinically validated antibiotics is that they address hotspots in complex biosynthetic machineries, whose functioning is essential for the bacterial cell. Therefore, an introduction to the biological targets-cell wall synthesis, topoisomerases, the DNA sliding clamp, and membrane-bound electron transport-is given for each of the leads presented here.
2016-10-19
2016-10-19
2016-10-05
Article
New Structural Templates for Clinically Validated and Novel Targets in Antimicrobial Drug Research and Development. 2016: Curr. Top. Microbiol. Immunol.
0070-217X
27704270
10.1007/82_2016_501
http://hdl.handle.net/10033/620555
Current topics in microbiology and immunology
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6205582019-08-30T11:27:16Zcom_10033_620533com_10033_620652com_10033_338554col_10033_621787col_10033_620534col_10033_620675
Coprinuslactone protects the edible mushroom Coprinus comatus against biofilm infections by blocking both quorum-sensing and MurA.
de Carvalho, Maira P
Gulotta, Giuseppe
do Amaral, Matheus W
Lünsdorf, Heinrich
Sasse, Florenz
Abraham, Wolf-Rainer
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Pathogens embedded in biofilms are involved in many infections and are very difficult to treat with antibiotics because of higher resistance compared to planktonic cells. Therefore, new approaches for their control are urgently needed. One way to search for biofilm dispersing compounds is to look at defense strategies of organisms exposed to wet environments, which makes them prone to biofilm infections. It is reasonable to assume that mushrooms have developed mechanisms to control biofilms on their sporocarps (fruiting bodies). A preliminary screening for biofilms on sporocarps revealed several species with few or no bacteria on their sporocarps. From the edible mushroom Coprinus comatus where no bacteria on the sporocarp could be detected (3R,4S)-2-methylene-3,4-dihydroxypentanoic acid 1,4-lactone, named coprinuslactone, was isolated. Coprinuslactone interfered with quorum-sensing and dispersed biofilms of Pseudomonas aeruginosa, where it also reduced the formation of the pathogenicity factors pyocyanin and rhamnolipid B. Coprinuslactone also damaged Staphylococcus aureus cells in biofilms at subtoxic concentrations. Furthermore, it inhibited UDP-N-acetylglucosamine enolpyruvyl transferase (MurA), essential for bacterial cell wall synthesis. These two modes of action ensure the inhibition of a broad spectrum of pathogens on the fruiting body but may also be useful for future clinical applications. This article is protected by copyright. All rights reserved.
2016-10-20
2016-10-20
2016-10-03
Article
Coprinuslactone protects the edible mushroom Coprinus comatus against biofilm infections by blocking both quorum-sensing and MurA. 2016 Environ. Microbiol.
1462-2920
27696655
10.1111/1462-2920.13560
http://hdl.handle.net/10033/620558
Environmental microbiology
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6206772019-08-30T11:27:46Zcom_10033_620533col_10033_620534
An aryl dioxygenase shows remarkable double dioxygenation capacity for diverse bis-aryl compounds, provided they are carbocyclic.
Overwin, Heike
González, Myriam
Méndez, Valentina
Seeger, Michael
Wray, Victor
Hofer, Bernd
Hel,holtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
The bacterial dioxygenation of mono- or polycyclic aromatic compounds is an intensely studied field. However, only in a few cases has the repeated dioxygenation of a substrate possessing more than a single aromatic ring been described. We previously characterized the aryl-hydroxylating dioxygenase BphA-B4h, an artificial hybrid of the dioxygenases of the biphenyl degraders Burkholderia xenovorans LB400 and Pseudomonas sp. strain B4-Magdeburg, which contains the active site of the latter enzyme, as an exceptionally powerful biocatalyst. We now show that this dioxygenase possesses a remarkable capacity for the double dioxygenation of various bicyclic aromatic compounds, provided that they are carbocyclic. Two groups of biphenyl analogues were examined: series A compounds containing one heterocyclic aromatic ring and series B compounds containing two homocyclic aromatic rings. Whereas all of the seven partially heterocyclic biphenyl analogues were solely dioxygenated in the homocyclic ring, four of the six carbocyclic bis-aryls were converted into ortho,meta-hydroxylated bis-dihydrodiols. Potential reasons for failure of heterocyclic dioxygenations are discussed. The obtained bis-dihydrodiols may, as we also show here, be enzymatically re-aromatized to yield the corresponding tetraphenols. This opens a way to a range of new polyphenolic products, a class of compounds known to exert multiple biological activities. Several of the obtained compounds are novel molecules.
2017-01-02
2017-01-02
2016-09
Article
An aryl dioxygenase shows remarkable double dioxygenation capacity for diverse bis-aryl compounds, provided they are carbocyclic. 2016, 100 (18):8053-61 Appl. Microbiol. Biotechnol.
1432-0614
27147529
10.1007/s00253-016-7570-0
http://hdl.handle.net/10033/620677
Applied microbiology and biotechnology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6207342019-08-30T11:36:05Zcom_10033_620533col_10033_620534
Biochemical and NMR analyses of an SF3b155-p14-U2AF-RNA interaction network involved in branch point definition during pre-mRNA splicing.
Spadaccini, Roberta
Reidt, Ulrich
Dybkov, Olexandr
Will, Cindy
Frank, Ronald
Stier, Gunter
Corsini, Lorenzo
Wahl, Markus C
Lührmann, Reinhard
Sattler, Michael
European Molecular Biology Laboratory Heidelberg, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
The p14 subunit of the essential splicing factor 3b (SF3b) can be cross-linked to the branch-point adenosine of pre-mRNA introns within the spliceosome. p14 stably interacts with the SF3b subunit SF3b155, which also binds the 65-kDa subunit of U2 auxiliary splicing factor (U2AF65). We combined biochemical and NMR techniques to study the conformation of p14 either alone or complexed with SF3b155 fragments, as well as an interaction network involving p14, SF3b155, U2AF65, and U2 snRNA/pre-mRNA. p14 comprises a canonical RNA recognition motif (RRM) with an additional C-terminal helix (alphaC) and a beta hairpin insertion. SF3b155 binds to the beta-sheet surface of p14, thereby occupying the canonical RNA-binding site of the p14 RRM. The minimal region of SF3b155 interacting with p14 (i.e., residues 381-424) consists of four alpha-helices, which are partially preformed in isolation. Helices alpha2 and alpha3 (residues 401-415) constitute the core p14-binding epitope. Regions of SF3b155 binding to p14 and U2AF65 are nonoverlapping. This allows for a simultaneous interaction of SF3b155 with both proteins, which may support the stable association of U2 snRNP with the pre-mRNA. p14-RNA interactions are modulated by SF3b155 and the RNA-binding site of the p14-SF3b155 complex involves the noncanonical beta hairpin insertion of the p14 RRM, consistent with the beta-sheet surface being occupied by the helical SF3b155 peptide and p14 helix alphaC. Our data suggest that p14 lacks inherent specificity for recognizing the branch point, but that some specificity may be achieved by scaffolding interactions involving other components of SF3b.
2017-01-20
2017-01-20
2006-03
Article
Biochemical and NMR analyses of an SF3b155-p14-U2AF-RNA interaction network involved in branch point definition during pre-mRNA splicing. 2006, 12 (3):410-25 RNA
1355-8382
16495236
10.1261/rna.2271406
http://hdl.handle.net/10033/620734
RNA (New York, N.Y.)
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6207352019-08-30T11:28:23Zcom_10033_620533col_10033_620534
Immunization of pigs to prevent disease in humans: construction and protective efficacy of a Salmonella enterica serovar Typhimurium live negative-marker vaccine.
Selke, Martin
Meens, Jochen
Springer, Sven
Frank, Ronald
Gerlach, Gerald-F
nstitute for Microbiology, Department of Infectious Diseases, University of Veterinary Medicine Hannover, Hannover, Germany.
Zoonotic infections caused by Salmonella enterica serovar Typhimurium pose a constant threat to consumer health, with the pig being a particularly major source of multidrug-resistant isolates. Vaccination, as a promising approach to reduce colonization and shedding, has been scarcely used, as it interferes with current control programs relying on serology as a means of herd classification. In order to overcome this problem, we set out to develop a negative-marker vaccine allowing the differentiation of infected from vaccinated animals (DIVA). Applying an immunoproteomic approach with two-dimensional gel electrophoresis, Western blot, and quadrupole time-of-flight tandem mass spectrometry, we identified the OmpD protein as a suitable negative marker. Using allelic exchange, we generated an isogenic mutant of the licensed live vaccine strain Salmoporc and showed that virulence of Salmoporc and that of the mutant strain, SalmoporcDeltaompD, were indistinguishable in BALB/c mice. In a pig infection experiment including two oral immunizations with SalmoporcDeltaompD and challenge with a multiresistant S. enterica serovar Typhimurium DT104 clinical isolate, we confirmed the protective efficacy of SalmoporcDeltaompD in pigs, showing a significant reduction of both clinical symptoms and colonization of lymph nodes and intestinal tract. OmpD immunogenic epitopes were determined by peptide spot array analyses. Upon testing of several 9-mer peptides, each including an immunogenic epitope, one peptide (positions F(100) to Y(108)) that facilitated the detection of infected animals independent of their vaccination status (DIVA function) was identified. The approach described overcomes the problems currently limiting the use of bacterial live vaccines and holds considerable potential for future developments in the field.
2017-01-20
2017-01-20
2007-05
Article
Immunization of pigs to prevent disease in humans: construction and protective efficacy of a Salmonella enterica serovar Typhimurium live negative-marker vaccine. 2007, 75 (5):2476-83 Infect. Immun.
0019-9567
17296750
10.1128/IAI.01908-06
http://hdl.handle.net/10033/620735
Infection and immunity
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6207392019-08-30T11:28:23Zcom_10033_620533col_10033_620534
EU-OPENSCREEN-chemical tools for the study of plant biology and resistance mechanisms.
Meiners, Torsten
Stechmann, Bahne
Frank, Ronald
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
EU-OPENSCREEN is an academic research infrastructure initiative in Europe for enabling researchers in all life sciences to take advantage of chemical biology approaches to their projects. In a collaborative effort of national networks in 16 European countries, EU-OPENSCREEN will develop novel chemical compounds with external users to address questions in, among other fields, systems and network biology (directed and selective perturbation of signalling pathways), structural biology (compound-target interactions at atomic resolution), pharmacology (early drug discovery and toxicology) and plant biology (response of wild or crop plants to environmental and agricultural substances). EU-OPENSCREEN supports all stages of a tool development project, including assay adaptation, high-throughput screening and chemical optimisation of the 'hit' compounds. All tool compounds and data will be made available to the scientific community. EU-OPENSCREEN integrates high-capacity screening platforms throughout Europe, which share a rationally selected compound collection comprising up to 300,000 (commercial and proprietary compounds collected from European chemists). By testing systematically this chemical collection in hundreds of assays originating from very different biological themes, the screening process generates enormous amounts of information about the biological activities of the substances and thereby steadily enriches our understanding of how and where they act.
2017-01-23
2017-01-23
2014-10
Article
EU-OPENSCREEN-chemical tools for the study of plant biology and resistance mechanisms. 2014, 7 (4):113-8 J Chem Biol
1864-6158
25320643
10.1007/s12154-014-0118-9
http://hdl.handle.net/10033/620739
Journal of chemical biology
en
oai:repository.helmholtz-hzi.de:10033/6207402019-08-30T11:28:23Zcom_10033_620533col_10033_620534
Multiple antibody targets on herpes B glycoproteins B and D identified by screening sera of infected rhesus macaques with peptide microarrays.
Hotop, Sven-Kevin
Abd El Wahed, Ahmed
Beutling, Ulrike
Jentsch, Dieter
Motzkus, Dirk
Frank, Ronald
Hunsmann, Gerhard
Stahl-Hennig, Christiane
Fritz, Hans-Joachim
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Herpes B virus (or Herpesvirus simiae or Macacine herpesvirus 1) is endemic in many populations of macaques, both in the wild and in captivity. The virus elicits only mild clinical symptoms (if any) in monkeys, but can be transmitted by various routes, most commonly via bites, to humans where it causes viral encephalitis with a high mortality rate. Hence, herpes B constitutes a considerable occupational hazard for animal caretakers, veterinarians and laboratory personnel. Efforts are therefore being made to reduce the risk of zoonotic infection and to improve prognosis after accidental exposure. Among the measures envisaged are serological surveillance of monkey colonies and specific diagnosis of herpes B zoonosis against a background of antibodies recognizing the closely related human herpes simplex virus (HSV). 422 pentadecapeptides covering, in an overlapping fashion, the entire amino acid sequences of herpes B proteins gB and gD were synthesized and immobilized on glass slides. Antibodies present in monkey sera that bind to subsets of the peptide collection were detected by microserological techniques. With 42 different rhesus macaque sera, 114 individual responses to 18 different antibody target regions (ATRs) were recorded, 17 of which had not been described earlier. This finding may pave the way for a peptide-based, herpes B specific serological diagnostic test.
2017-01-23
2017-01-23
2014
Article
Multiple antibody targets on herpes B glycoproteins B and D identified by screening sera of infected rhesus macaques with peptide microarrays. 2014, 9 (1):e86857 PLoS ONE
1932-6203
24497986
10.1371/journal.pone.0086857
http://hdl.handle.net/10033/620740
PloS one
en
oai:repository.helmholtz-hzi.de:10033/6207412019-08-30T11:31:49Zcom_10033_620533col_10033_620534
Peptide-mediated interference with influenza A virus polymerase.
Ghanem, Alexander
Mayer, Daniel
Chase, Geoffrey
Tegge, Werner
Frank, Ronald
Kochs, Georg
García-Sastre, Adolfo
Schwemmle, Martin
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
The assembly of the polymerase complex of influenza A virus from the three viral polymerase subunits PB1, PB2, and PA is required for viral RNA synthesis. We show that peptides which specifically bind to the protein-protein interaction domains in the subunits responsible for complex formation interfere with polymerase complex assembly and inhibit viral replication. Specifically, we provide evidence that a 25-amino-acid peptide corresponding to the PA-binding domain of PB1 blocks the polymerase activity of influenza A virus and inhibits viral spread. Targeting polymerase subunit interactions therefore provides a novel strategy to develop antiviral compounds against influenza A virus or other viruses.
2017-01-24
2017-01-24
2007-07
Article
Peptide-mediated interference with influenza A virus polymerase. 2007, 81 (14):7801-4 J. Virol.
0022-538X
17494067
10.1128/JVI.00724-07
http://hdl.handle.net/10033/620741
Journal of virology
en
oai:repository.helmholtz-hzi.de:10033/6207452019-08-30T11:27:46Zcom_10033_620533col_10033_620534
The interaction of the gammaherpesvirus 68 orf73 protein with cellular BET proteins affects the activation of cell cycle promoters.
Ottinger, Matthias
Pliquet, Daniel
Christalla, Thomas
Frank, Ronald
Stewart, James P
Schulz, Thomas F
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Infection of mice with murine gammaherpesvirus 68 (MHV-68) provides a valuable animal model for gamma-2 herpesvirus (rhadinovirus) infection and pathogenesis. The MHV-68 orf73 protein has been shown to be required for the establishment of viral latency in vivo. This study describes a novel transcriptional activation function of the MHV-68 orf73 protein and identifies the cellular bromodomain containing BET proteins Brd2/RING3, Brd3/ORFX, and BRD4 as interaction partners for the MHV-68 orf73 protein. BET protein members are known to interact with acetylated histones, and Brd2 and Brd4 have been implicated in fundamental cellular processes, including cell cycle regulation and transcriptional regulation. Using MHV-68 orf73 peptide array assays, we identified Brd2 and Brd4 interaction sites in the orf73 protein. Mutation of one binding site led to a loss of the interaction with Brd2/4 but not the retinoblastoma protein Rb, to impaired chromatin association, and to a decreased ability to activate the BET-responsive cyclin D1, D2, and E promoters. The results therefore pinpoint the binding site for Brd2/4 in a rhadinoviral orf73 protein and suggest that the recruitment of a member of the BET protein family allows the MHV-68 orf73 protein to activate the promoters of G(1)/S cyclins. These findings point to parallels between the transcriptional activator functions of rhadinoviral orf73 proteins and papillomavirus E2 proteins.
2017-01-24
2017-01-24
2009-05
Article
The interaction of the gammaherpesvirus 68 orf73 protein with cellular BET proteins affects the activation of cell cycle promoters. 2009, 83 (9):4423-34 J. Virol.
1098-5514
19244327
10.1128/JVI.02274-08
http://hdl.handle.net/10033/620745
Journal of virology
en
oai:repository.helmholtz-hzi.de:10033/6207462019-08-30T11:28:23Zcom_10033_620533col_10033_620534
Identification of high-affinity PB1-derived peptides with enhanced affinity to the PA protein of influenza A virus polymerase.
Wunderlich, Kerstin
Juozapaitis, Mindaugas
Ranadheera, Charlene
Kessler, Ulrich
Martin, Arnold
Eisel, Jessica
Beutling, Ulrike
Frank, Ronald
Schwemmle, Martin
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
The influenza A virus polymerase complex, consisting of the subunits PB1, PB2, and PA, represents a promising target for the development of new antiviral drugs. We have previously demonstrated the feasibility of targeting the protein-protein interaction domain between PA and PB1 using peptides derived from the extreme N terminus of PB1 (amino acids [aa] 1 to 15), comprising the PA-binding domain of PB1. To increase the binding affinity of these peptides, we performed a systematic structure-affinity relationship analysis. Alanine and aspartic acid scans revealed that almost all amino acids in the core binding region (aa 5 to 11) are indispensable for PA binding. Using a library of immobilized peptides representing all possible single amino acid substitutions, we were able to identify amino acid positions outside the core PA-binding region (aa 1, 3, 12, 14, and 15) that are variable and can be replaced by affinity-enhancing residues. Surface plasmon resonance binding studies revealed that combination of several affinity-enhancing mutations led to an additive effect. Thus, the feasibility to enhance the PA-binding affinity presents an intriguing possibility to increase antiviral activity of the PB1-derived peptide and one step forward in the development of an antiviral drug against influenza A viruses.
2017-01-24
2017-01-24
2011-02
Article
Identification of high-affinity PB1-derived peptides with enhanced affinity to the PA protein of influenza A virus polymerase. 2011, 55 (2):696-702 Antimicrob. Agents Chemother.
1098-6596
21135188
10.1128/AAC.01419-10
http://hdl.handle.net/10033/620746
Antimicrobial agents and chemotherapy
en
oai:repository.helmholtz-hzi.de:10033/6207482019-08-30T11:34:22Zcom_10033_620533col_10033_620534
Archazolid and apicularen: novel specific V-ATPase inhibitors.
Huss, Markus
Sasse, Florenz
Kunze, Brigitte
Jansen, Rolf
Steinmetz, Heinrich
Ingenhorst, Gudrun
Zeeck, Axel
Wieczorek, Helmut
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
V-ATPases constitute a ubiquitous family of heteromultimeric, proton translocating proteins. According to their localization in a multitude of eukaryotic membranes, they energize many different transport processes. Since their malfunction is correlated with various diseases in humans, the elucidation of the properties of this enzyme for the development of selective inhibitors and drugs is one of the challenges in V-ATPase research.
2017-01-26
2017-01-26
2005-08-04
Article
Archazolid and apicularen: novel specific V-ATPase inhibitors. 2005, 6:13 BMC Biochem.
1471-2091
16080788
10.1186/1471-2091-6-13
http://hdl.handle.net/10033/620748
BMC biochemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6207492019-08-30T11:34:22Zcom_10033_620533col_10033_620534
Analysis of gene expression data from non-small cell lung carcinoma cell lines reveals distinct sub-classes from those identified at the phenotype level.
Dalby, Andrew R
Emam, Ibrahim
Franke, Raimo
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Microarray data from cell lines of Non-Small Cell Lung Carcinoma (NSCLC) can be used to look for differences in gene expression between the cell lines derived from different tumour samples, and to investigate if these differences can be used to cluster the cell lines into distinct groups. Dividing the cell lines into classes can help to improve diagnosis and the development of screens for new drug candidates. The micro-array data is first subjected to quality control analysis and then subsequently normalised using three alternate methods to reduce the chances of differences being artefacts resulting from the normalisation process. The final clustering into sub-classes was carried out in a conservative manner such that sub-classes were consistent across all three normalisation methods. If there is structure in the cell line population it was expected that this would agree with histological classifications, but this was not found to be the case. To check the biological consistency of the sub-classes the set of most strongly differentially expressed genes was be identified for each pair of clusters to check if the genes that most strongly define sub-classes have biological functions consistent with NSCLC.
2017-01-26
2017-01-26
2012
Article
Analysis of gene expression data from non-small cell lung carcinoma cell lines reveals distinct sub-classes from those identified at the phenotype level. 2012, 7 (11):e50253 PLoS ONE
1932-6203
23209689
10.1371/journal.pone.0050253
http://hdl.handle.net/10033/620749
PloS one
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6207512019-08-30T11:27:16Zcom_10033_620533col_10033_620534
The disabled 1 phosphotyrosine-binding domain binds to the internalization signals of transmembrane glycoproteins and to phospholipids.
Howell, B W
Lanier, L M
Frank, R
Gertler, F B
Cooper, J A
Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
Disabled gene products are important for nervous system development in drosophila and mammals. In mice, the Dab1 protein is thought to function downstream of the extracellular protein Reln during neuronal positioning. The structures of Dab proteins suggest that they mediate protein-protein or protein-membrane docking functions. Here we show that the amino-terminal phosphotyrosine-binding (PTB) domain of Dab1 binds to the transmembrane glycoproteins of the amyloid precursor protein (APP) and low-density lipoprotein receptor families and the cytoplasmic signaling protein Ship. Dab1 associates with the APP cytoplasmic domain in transfected cells and is coexpressed with APP in hippocampal neurons. Screening of a set of altered peptide sequences showed that the sequence GYXNPXY present in APP family members is an optimal binding sequence, with approximately 0.5 microM affinity. Unlike other PTB domains, the Dab1 PTB does not bind to tyrosine-phosphorylated peptide ligands. The PTB domain also binds specifically to phospholipid bilayers containing phosphatidylinositol 4P (PtdIns4P) or PtdIns4,5P2 in a manner that does not interfere with protein binding. We propose that the PTB domain permits Dab1 to bind specifically to transmembrane proteins containing an NPXY internalization signal.
2017-01-26
2017-01-26
1999-07
Article
The disabled 1 phosphotyrosine-binding domain binds to the internalization signals of transmembrane glycoproteins and to phospholipids. 1999, 19 (7):5179-88 Mol. Cell. Biol.
0270-7306
10373567
http://hdl.handle.net/10033/620751
Molecular and cellular biology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208002019-08-30T11:27:16Zcom_10033_620533col_10033_620534
14-3-3 proteins are constituents of the insoluble glycoprotein framework of the chlamydomonas cell wall.
Voigt, Jürgen
Frank, Ronald
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
The cell wall of the unicellular green alga Chlamydomonas reinhardtii consists predominantly of Hyp-rich glycoproteins, which also occur in the extracellular matrix of multicellular green algae and higher plants. In addition to the Hyp-rich polypeptides, the insoluble glycoprotein framework of the Chlamydomonas cell wall contains minor amounts of 14-3-3 proteins, as revealed by immunochemical studies and mass spectroscopic analysis of tryptic peptides. Polypeptides immunologically related to the 14-3-3 proteins also were found in the culture medium of Chlamydomonas. The levels of two of these 14-3-3-related polypeptides were decreased in the culture medium of the wall-deficient mutant cw-15. These findings indicate that 14-3-3 proteins are involved in the cross-linking of Hyp-rich glycoproteins in the Chlamydomonas cell wall.
2017-02-01
2017-02-01
2003-06
Article
14-3-3 proteins are constituents of the insoluble glycoprotein framework of the chlamydomonas cell wall. 2003, 15 (6):1399-413 Plant Cell
1040-4651
12782732
http://hdl.handle.net/10033/620800
The Plant cell
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208012019-08-30T11:36:05Zcom_10033_620533col_10033_620534
Kaposi's sarcoma-associated herpesvirus viral interferon regulatory factor 4 (vIRF4/K10) is a novel interaction partner of CSL/CBF1, the major downstream effector of Notch signaling.
Heinzelmann, Katharina
Scholz, Barbara A
Nowak, Agnes
Fossum, Even
Kremmer, Elisabeth
Haas, Juergen
Frank, Ronald
Kempkes, Bettina
Helmholtz Centre for infection research. Inhoffenstr. 7. 38124 Braunschweig, Germany.
In cells infected with the Kaposi's sarcoma-associated herpesvirus (KSHV), CSL/CBF1 signaling is essential for viral replication and promotes the survival of KSHV-infected cells. CSL/CBF1 is a DNA adaptor molecule which recruits coactivator and corepressor complexes to regulate viral and cellular gene transcription and which is a major downstream effector molecule of activated Notch. The interaction of KSHV RTA and LANA with CSL/CBF1 has been shown to balance the lytic and latent viral life cycle. Here we report that a third KSHV protein, viral interferon regulatory factor 4 (vIRF4/K10), but none of the three other KSHV-encoded vIRFs, interacts with CSL/CBF1. Two regions of vIRF4 with dissimilar affinities contribute to CSL/CBF1 binding. Similar to Notch, vIRF4 targets the hydrophobic pocket in the beta trefoil domain of CSL/CBF1 through a short peptide motif which closely resembles a motif found in Notch but does not strictly follow the ΦWΦP consensus conserved in human and mouse Notch proteins. Our results suggest that vIRF4 might compete with Notch for CSL/CBF1 binding and signaling.
2017-02-02
2017-02-02
2010-12
Article
Kaposi's sarcoma-associated herpesvirus viral interferon regulatory factor 4 (vIRF4/K10) is a novel interaction partner of CSL/CBF1, the major downstream effector of Notch signaling. 2010, 84 (23):12255-64 J. Virol.
1098-5514
20861242
10.1128/JVI.01484-10
http://hdl.handle.net/10033/620801
Journal of virology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208022019-08-30T11:31:47Zcom_10033_620533col_10033_620534
Minimum information about a protein affinity reagent (MIAPAR).
Bourbeillon, Julie
Orchard, Sandra
Benhar, Itai
Borrebaeck, Carl
de Daruvar, Antoine
Dübel, Stefan
Frank, Ronald
Gibson, Frank
Gloriam, David
Haslam, Niall
Hiltker, Tara
Humphrey-Smith, Ian
Hust, Michael
Juncker, David
Koegl, Manfred
Konthur, Zoltàn
Korn, Bernhard
Krobitsch, Sylvia
Muyldermans, Serge
Nygren, Per-Ake
Palcy, Sandrine
Polic, Bojan
Rodriguez, Henry
Sawyer, Alan
Schlapshy, Martin
Snyder, Michael
Stoevesandt, Oda
Taussig, Michael J
Templin, Markus
Uhlen, Matthias
van der Maarel, Silvere
Wingren, Christer
Hermjakob, Henning
Sherman, David
Helmholtz Centre for infection research. Inhoffenstr. 7. 38124 Braunschweig, Germany.
2017-02-02
2017-02-02
2010-07
Article
Minimum information about a protein affinity reagent (MIAPAR). 2010, 28 (7):650-3 Nat. Biotechnol.
1546-1696
20622827
10.1038/nbt0710-650
http://hdl.handle.net/10033/620802
Nature biotechnology
en
info:eu-repo/grantAgreement/EC/FP7/212111
http://creativecommons.org/licenses/by-nc-sa/4.0/
openAccess
oai:repository.helmholtz-hzi.de:10033/6208032019-08-30T11:28:51Zcom_10033_620533col_10033_620534
JKTBP1 is involved in stabilization and IRES-dependent translation of NRF mRNAs by binding to 5' and 3' untranslated regions.
Omnus, Deike Johanne
Mehrtens, Sarah
Ritter, Birgit
Resch, Klaus
Yamada, Michiyuki
Frank, Ronald
Nourbakhsh, Mahtab
Reboll, Marc René
Helmholtz Centre for infection research. Inhoffenstr. 7. 38124 Braunschweig, Germany.
Heterogeneous nuclear ribonucleoprotein D-like protein (JKTBP) 1 was implicated in cap-independent translation by binding to the internal ribosome entry site in the 5' untranslated region (UTR) of NF-κB-repressing factor (NRF). Two different NRF mRNAs have been identified so far, both sharing the common 5' internal ribosome entry site but having different length of 3' UTRs. Here, we used a series of DNA and RNA luciferase reporter constructs comprising 5', 3' or both NRF UTRs to study the effect of JKTBP1 on translation of NRF mRNA variants. The results indicate that JKTBP1 regulates the level of NRF protein expression by binding to both NRF 5' and 3' UTRs. Using successive deletion and point mutations as well as RNA binding studies, we define two distinct JKTBP1 binding elements in NRF 5' and 3' UTRs. Furthermore, JKTBP1 requires two distinct RNA binding domains to interact with NRF UTRs and a short C-terminal region for its effect on NRF expression. Together, our study shows that JKTBP1 contributes to NRF protein expression via two disparate mechanisms: mRNA stabilization and cap-independent translation. By binding to 5' UTR, JKTBP1 increases the internal translation initiation in both NRF mRNA variants, whereas its binding to 3' UTR elevated primarily the stability of the major NRF mRNA. Thus, JKTBP1 is a key regulatory factor linking two pivotal control mechanisms of NRF gene expression: the cap-independent translation initiation and mRNA stabilization.
2017-02-02
2017-02-02
2011-04-08
Article
JKTBP1 is involved in stabilization and IRES-dependent translation of NRF mRNAs by binding to 5' and 3' untranslated regions. 2011, 407 (4):492-504 J. Mol. Biol.
1089-8638
21300069
10.1016/j.jmb.2011.01.050
http://hdl.handle.net/10033/620803
Journal of molecular biology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208082019-08-30T11:29:17Zcom_10033_620533col_10033_620534
Unprecedented deoxygenation at C-7 of the ansamitocin core during mutasynthetic biotransformations.
Knobloch, Tobias
Dräger, Gerald
Collisi, Wera
Sasse, Florenz
Kirschning, Andreas
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
We describe the unprecedented formation of six ansamitocin derivatives that are deoxygenated at C-7 of the ansamitocin core, obtained during fermentation experiments by employing a variety of Actinosynnema pretiosum mutants and mutasynthetic approaches. We suggest that the formation of these derivatives is based on elimination at C-7/C-8 followed by reduction(s) of the intermediate enone. In bioactivity tests, only ansamitocin derivatives bearing an ester side chain at C-3 showed strong antiproliferative activity.
2017-02-06
2017-02-06
2012
Article
Unprecedented deoxygenation at C-7 of the ansamitocin core during mutasynthetic biotransformations. 2012, 8:861-9 Beilstein J Org Chem
1860-5397
23015834
10.3762/bjoc.8.96
http://hdl.handle.net/10033/620808
Beilstein journal of organic chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208102019-08-30T11:33:57Zcom_10033_620533col_10033_620534
Novel peptidomimetic compounds containing redox active chalcogens and quinones as potential anticancer agents.
Shaaban, Saad
Diestel, Randi
Hinkelmann, Bettina
Muthukumar, Yazh
Verma, Rajeshwar P
Sasse, Florenz
Jacob, Claus
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Many types of cancer cells are associated with a disturbed intracellular redox balance and oxidative stress (OS). Among the various agents employed to modulate the intracellular redox state of cells, certain redox catalysts containing quinone and chalcogen moieties have shown considerable promise. Passerini multicomponent reaction has been developed for the synthesis of agents combining two, three or even four redox centers in one molecule in a good yield. When incubated with cancer cells these agents inhibited cell proliferation and induced apoptotic cell death. Interestingly, some of these redox active compounds exhibited quite low toxicity with normal cells. The cause was obviously OS, which was reflected by significant decrease in reduced glutathione, subsequently cell cycle arrest and induction of apoptosis.
2017-02-07
2017-02-07
2012-12
Article
Novel peptidomimetic compounds containing redox active chalcogens and quinones as potential anticancer agents. 2012, 58:192-205 Eur J Med Chem
1768-3254
23124216
10.1016/j.ejmech.2012.09.033
http://hdl.handle.net/10033/620810
European journal of medicinal chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208122019-08-30T11:29:17Zcom_10033_620533col_10033_620534
Generation of novel-substrate-accepting biphenyl dioxygenases through segmental random mutagenesis and identification of residues involved in enzyme specificity.
Zielinski, Marco
Kahl, Silke
Standfuss-Gabisch, Christine
Cámara, Beatriz
Seeger, Michael
Hofer, Bernd
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Aryl-hydroxylating dioxygenases are of interest for the degradation of persistant aromatic pollutants, such as polychlorobiphenyls (PCBs), or as catalysts for the functionalization of aromatic scaffolds. In order to achieve dioxygenation of technical mixtures of PCBs, enzymes with broadened or altered substrate ranges are essential. To alter the substrate specificity of the biphenyl dioxygenase (BphA) of Burkholderia xenovorans LB400, we applied a directed evolution approach that used structure-function relationship data to target random mutageneses to specific segments of the enzyme. The limitation of random amino acid (AA) substitutions to regions that are critical for substrate binding and the exclusion of AA exchanges from positions that are essential for catalytic activity yielded enzyme variants of interest at comparatively high frequencies. After only a single mutagenic cycle, 10 beneficial variants were detected in a library of fewer than 1,000 active enzymes. Compared to the parental BphA, they showed between 5- and 200-fold increased turnover of chlorinated biphenyls, with substituent patterns that rendered them largely recalcitrant to attack by BphA-LB400. Determination of their sequences identified AAs that prevent the acceptance of specific PCBs by the wild-type enzyme, such as Pro334 and Phe384. The results suggest prime targets for subsequent cycles of BphA modification. Correlations with a three-dimensional model of the enzyme indicated that most of the exchanges with major influence on substrate turnover do not involve pocket-lining residues and had not been predictable through structural modeling.
2017-02-08
2017-02-08
2006-03
Article
Generation of novel-substrate-accepting biphenyl dioxygenases through segmental random mutagenesis and identification of residues involved in enzyme specificity. 2006, 72 (3):2191-9 Appl. Environ. Microbiol.
0099-2240
16517671
10.1128/AEM.72.3.2191-2199.2006
http://hdl.handle.net/10033/620812
Applied and environmental microbiology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208132019-08-30T11:29:17Zcom_10033_620533col_10033_620534
SAR studies on hydropentalene derivatives--Important core units of biologically active tetramic acid macrolactams and ptychanolides.
Lutz, Vanessa
Mannchen, Fabian
Krebs, Michael
Park, Natja
Krüger, Claudia
Raja, Aruna
Sasse, Florenz
Baro, Angelika
Laschat, Sabine
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Structurally diverse bicyclo[3.3.0]octanes were prepared and tested for their biological activity. Both the antiproliferative activity and the results of phenotypic characterization varied with the substitution patterns. Two derivatives displayed high inhibitory (IC50 ≤3μM) activity against the L-929 cell line, but differed in their mode of action. A cluster analysis with impedance profiling data showed the two compounds in relationship to microtubule interfering compounds. In PtK2 cells treated with both derivatives a perturbing effect on the microtubular network was observed, whereas the actin cytoskeleton in incubated PtK2 cells was disturbed only by one compound. The effects on tubulin and actin polymerization could be confirmed by in vitro polymerization experiments.
2017-02-08
2017-02-08
2014-07-01
Article
SAR studies on hydropentalene derivatives--Important core units of biologically active tetramic acid macrolactams and ptychanolides. 2014, 22 (13):3252-61 Bioorg. Med. Chem.
1464-3391
24856181
10.1016/j.bmc.2014.04.063
http://hdl.handle.net/10033/620813
Bioorganic & medicinal chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208152019-08-30T11:29:15Zcom_10033_620533col_10033_620534
First Syntheses of Melophlins P, Q, and R, and Effects of Melophlins on the Growth of Microorganisms and Tumor Cells
Biersack, Bernhard
Diestel, Randi
Jagusch, Carsten
Rapp, Georg
Sasse, Florenz
Schobert, Rainer
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
2017-02-08
2017-02-08
2008-11
Article
First Syntheses of Melophlins P, Q, and R, and Effects of Melophlins on the Growth of Microorganisms and Tumor Cells 2008, 5 (11):2423 Chemistry & Biodiversity
16121872
16121880
10.1002/cbdv.200890207
http://hdl.handle.net/10033/620815
Chemistry & Biodiversity
http://doi.wiley.com/10.1002/cbdv.200890207
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208162019-08-30T11:33:57Zcom_10033_620533col_10033_620534
Sulfur, selenium and tellurium pseudopeptides: synthesis and biological evaluation.
Shaaban, Saad
Sasse, Florenz
Burkholz, Torsten
Jacob, Claus
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
A new series of sulfur, selenium and tellurium peptidomimetic compounds was prepared employing the Passerini and Ugi isocyanide based multicomponent reactions (IMCRs). These reactions were clearly superior to conventional methods traditionally used for organoselenium and organotellurium synthesis, such as classical nucleophilic substitution and coupling methods. From the biological point of view, these compounds are of considerable interest because of suspected anticancer and antimicrobial activities. While the sulfur and selenium containing compounds generally did not show either anticancer or antimicrobial activities, their tellurium based counterparts frequently exhibited antimicrobial activity and were also cytotoxic. Some of the compounds synthesized even showed selective activity against certain cancer cells in cell culture. These compounds induced a cell cycle delay in the G0/G1 phase. At closer inspection, the ER and the actin cytoskeleton appeared to be the primary cellular targets of these tellurium compounds, in line with some of our previous studies. As most of these peptidomimetic compounds also comply with Lipinski's Rule of Five, they promise good bioavailability, which needs to be studied as part of future investigations.
2017-02-13
2017-02-13
2014-07-15
Article
Sulfur, selenium and tellurium pseudopeptides: synthesis and biological evaluation. 2014, 22 (14):3610-9 Bioorg. Med. Chem.
1464-3391
24890655
10.1016/j.bmc.2014.05.019
http://hdl.handle.net/10033/620816
Bioorganic & medicinal chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208222019-08-30T11:36:05Zcom_10033_620533col_10033_620534
High level expression of a recombinant amylosucrase gene and selected properties of the enzyme.
Schneider, Jens
Fricke, Christin
Overwin, Heike
Hofer, Bernd
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Two high-level heterologous expression systems for amylosucrase genes have been constructed. One depends on sigma-70 bacterial RNA polymerase, the other on phage T7 RNA polymerase. Translational fusions were formed between slightly truncated versions of the gene from Neisseria polysaccharea and sequences of expression vectors pQE-81L or pET33b(+), respectively. These constructs were introduced into different Escherichia coli strains. The resulting recombinants yielded up to 170 mg of dissolved enzyme per litre of culture at a moderate cell density of five OD(600). To our knowledge, this is the highest yield per cell described so far for amylosucrases. The recombinant enzymes could rapidly be purified through the use of histidine tags in the N-terminally attached sequences. These segments did not alter catalytic properties and therefore need not be removed for most applications. Investigations with glucose and malto-oligosaccharides of different lengths identified rate-limiting steps in the elongation (acceptor reaction) and truncation (donor reaction) of these substrates. The elongation of maltotriose and its reversal, the truncation of maltotetraose, were found to be particularly slow reactions. Potential reasons are discussed, based on the crystal structure of the enzyme. It is furthermore shown that amylosucrase is able to synthesise mixed disaccharides. All of the glucose epimers mannose, allose, and galactose served as acceptors, yielding between one and three main products. We also demonstrate that, as an alternative to the use of purified amylosucrase, cells of the constructed recombinant strains can be used to carry out glucosylations of acceptors.
2017-02-16
2017-02-16
2011-03
Article
High level expression of a recombinant amylosucrase gene and selected properties of the enzyme. 2011, 89 (6):1821-9 Appl. Microbiol. Biotechnol.
1432-0614
21113589
10.1007/s00253-010-3000-x
http://hdl.handle.net/10033/620822
Applied microbiology and biotechnology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208232019-08-30T11:33:05Zcom_10033_620533col_10033_620534
Allogeneic gene-modified tumor cells (RCC-26/IL-7/CD80) as a vaccine in patients with metastatic renal cell cancer: a clinical phase-I study.
Westermann, J
Flörcken, A
Willimsky, G
van Lessen, A
Kopp, J
Takvorian, A
Jöhrens, K
Lukowsky, A
Schönemann, C
Sawitzki, B
Pohla, H
Frank, Ronald
Dörken, B
Schendel, D J
Blankenstein, T
Pezzutto, A
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Despite novel targeted agents, prognosis of metastatic renal cell cancer (RCC) remains poor, and experimental therapeutic strategies are warranted. Transfection of tumor cells with co-stimulatory molecules and/or cytokines is able to increase immunogenicity. Therefore, in our clinical study, 10 human leukocyte antigen (HLA)-A(*)0201(+) patients with histologically-confirmed progressive metastatic clear cell RCC were immunized repetitively over 22 weeks with 2.5-40 × 10(6) interleukin (IL)-7/CD80 cotransfected allogeneic HLA-A(*)0201(+) tumor cells (RCC26/IL-7/CD80). Endpoints of the study were feasibility, safety, immunological and clinical responses. Vaccination was feasible and safe. In all, 50% of the patients showed stable disease throughout the study; the median time to progression was 18 weeks. However, vaccination with allogeneic RCC26/IL-7/CD80 tumor cells was not able to induce TH1-polarized immune responses. A TH2 cytokine profile with increasing amounts of antigen-specific IL-10 secretion was observed in most of the responding patients. Interferon-γ secretion by patient lymphocytes upon antigen-specific and non-specific stimulation was substantially impaired, both before and during vaccination, as compared with healthy controls. This is possibly due to profound tumor-induced immunosuppression, which may prevent induction of antitumor immune responses by the gene-modified vaccine. Vaccination in minimal residual disease with concurrent depletion of regulatory cells might be one strategy to overcome this limitation.
2017-02-16
2017-02-16
2011-04
Article
Allogeneic gene-modified tumor cells (RCC-26/IL-7/CD80) as a vaccine in patients with metastatic renal cell cancer: a clinical phase-I study. 2011, 18 (4):354-63 Gene Ther.
1476-5462
21068778
10.1038/gt.2010.143
http://hdl.handle.net/10033/620823
Gene therapy
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208242019-08-30T11:36:05Zcom_10033_620533col_10033_620534
Mapping of NRF binding motifs of NF-kappaB p65 subunit.
Reboll, Marc R
Schweda, Aike T
Bartels, Myriam
Franke, Raimo
Frank, Ronald
Nourbakhsh, Mahtab
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
NF-kappaB repressing factor (NRF) is a nuclear transcription factor that binds to a specific DNA sequence in NF-kappaB target promoters. Previous reports suggested that NRF interferes with the transcriptional activity of NF-kappaB binding sites through a direct interaction with NF-kappaB subunits. The aim of this study was to map specific NRF binding domains in the NF-kappaB proteins, p65 and p50. Our data demonstrate that NRF is able to interact with the p65 subunit and inhibit its transcription enhancing activity in reporter gene experiments. Using tandem affinity purifications (TAP), we show that NRF protein significantly binds to the endogenous p65, subunit but not to the p50 subunit. The selective binding activity of the NRF protein is consistently mediated by the N-terminal domain of NRF (Amino acids 1-380). Moreover, the Rel homology domain (RHD) of p65 is sufficient for binding to the N-terminal domain of NRF. Using detailed peptide mapping studies, we finally identify three peptide motifs in p65 RHD showing distinctive binding specificities for the NRF protein. According to the predicted structure of p65, all three peptide motifs align within an exposed region of p65 and might hint at promising targets for inhibitors.
2017-02-16
2017-02-16
2011-11
Article
Mapping of NRF binding motifs of NF-kappaB p65 subunit. 2011, 150 (5):553-62 J. Biochem.
1756-2651
21821668
10.1093/jb/mvr099
http://hdl.handle.net/10033/620824
Journal of biochemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208252019-08-30T11:27:16Zcom_10033_620533col_10033_620534
Phosphatidylinositol 3'-kinase activity is critical for initiating the oxidative burst and bacterial destruction during CEACAM3-mediated phagocytosis.
Buntru, Alexander
Kopp, Kathrin
Voges, Maike
Frank, Ronald
Bachmann, Verena
Hauck, Christof R
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Carcinoembryonic antigen-related cell adhesion molecule 3 (CEACAM3) is an immunoglobulin-related receptor expressed on human granulocytes. CEACAM3 functions as a single chain phagocytotic receptor recognizing gram-negative bacteria such as Neisseria gonorrhoeae, which possess CEACAM-binding adhesins on their surface. The cytoplasmic domain of CEACAM3 contains an immunoreceptor tyrosine-based activation motif (ITAM)-like sequence that is phosphorylated upon receptor engagement. Here we show that the SH2 domains of the regulatory subunit of phosphatidylinositol 3'-kinase (PI3K) bind to tyrosine residue 230 of CEACAM3 in a phosphorylation-dependent manner. PI3K is rapidly recruited and directly associates with CEACAM3 upon bacterial binding as shown by FRET analysis. Although PI3K activity is not required for efficient uptake of the bacteria by CEACAM3-transfected cells or primary human granulocytes, it is critical for the stimulated production of reactive oxygen species by infected phagocytes and the intracellular degradation of CEACAM-binding bacteria. Together, our results highlight the ability of CEACAM3 to coordinate signaling events that not only mediate bacterial uptake, but also trigger the killing of internalized pathogens.
2017-02-16
2017-02-16
2011-03-18
Article
Phosphatidylinositol 3'-kinase activity is critical for initiating the oxidative burst and bacterial destruction during CEACAM3-mediated phagocytosis. 2011, 286 (11):9555-66 J. Biol. Chem.
1083-351X
21216968
10.1074/jbc.M110.216085
http://hdl.handle.net/10033/620825
The Journal of biological chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208262019-08-30T11:27:16Zcom_10033_620533col_10033_620534
Characterization of biphenyl dioxygenase sequences and activities encoded by the metagenomes of highly polychlorobiphenyl-contaminated soils.
Standfuss-Gabisch, Christine
Al-Halbouni, Djamila
Hofer, Bernd
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Total extracted DNA from two heavily polychlorobiphenyl-contaminated soils was analyzed with respect to biphenyl dioxygenase sequences and activities. This was done by PCR amplification and cloning of a DNA segment encoding the active site of the enzyme. The translated sequences obtained fell into three similarity clusters (I to III). Sequence identities were high within but moderate or low between the clusters. Members of clusters I and II showed high sequence similarities with well-known biphenyl dioxygenases. Cluster III showed low (43%) sequence identity with a biphenyl dioxygenase from Rhodococcus jostii RHA1. Amplicons from the three clusters were used to reconstitute and express complete biphenyl dioxygenase operons. In most cases, the resulting hybrid dioxygenases were detected in cell extracts of the recombinant hosts. At least 83% of these enzymes were catalytically active. Several amino acid exchanges were identified that critically affected activity. Chlorobiphenyl turnover by the enzymes containing the prototype sequences of clusters I and II was characterized with 10 congeners that were major, minor, or not constituents of the contaminated soils. No direct correlations were observed between on-site concentrations and rates of productive dioxygenations of these chlorobiphenyls. The prototype enzymes displayed markedly different substrate and product ranges. The cluster II dioxygenase possessed a broader substrate spectrum toward the assayed congeners, whereas the cluster I enzyme was superior in the attack of ortho-chlorinated aromatic rings. These results demonstrate the feasibility of the applied approach to functionally characterize dioxygenase activities of soil metagenomes via amplification of incomplete genes.
2017-02-16
2017-02-16
2012-04
Article
Characterization of biphenyl dioxygenase sequences and activities encoded by the metagenomes of highly polychlorobiphenyl-contaminated soils. 2012, 78 (8):2706-15 Appl. Environ. Microbiol.
1098-5336
22327590
10.1128/AEM.07381-11
http://hdl.handle.net/10033/620826
Applied and environmental microbiology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208272019-08-30T11:36:05Zcom_10033_620533col_10033_620534
High immune response rates and decreased frequencies of regulatory T cells in metastatic renal cell carcinoma patients after tumor cell vaccination.
Pohla, Heike
Buchner, Alexander
Stadlbauer, Birgit
Frankenberger, Bernhard
Stevanovic, Stefan
Walter, Steffen
Frank, Ronald
Schwachula, Tim
Olek, Sven
Kopp, Joachim
Willimsky, Gerald
Stief, Christian G
Hofstetter, Alfons
Pezzutto, Antonio
Blankenstein, Thomas
Oberneder, Ralph
Schendel, Dolores J
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Our previously reported phase I clinical trial with the allogeneic gene-modified tumor cell line RCC-26/CD80/IL-2 showed that vaccination was well tolerated and feasible in metastatic renal cell carcinoma (RCC) patients. Substantial disease stabilization was observed in most patients despite a high tumor burden at study entry. To investigate alterations in immune responses that might contribute to this effect, we performed an extended immune monitoring that included analysis of reactivity against multiple antigens, cytokine/chemokine changes in serum and determination of the frequencies of immune suppressor cell populations, including natural regulatory T cells (nTregs) and myeloid-derived suppressor cell subsets (MDSCs). An overall immune response capacity to virus-derived control peptides was present in 100% of patients before vaccination. Vaccine-induced immune responses to tumor-associated antigens occurred in 75% of patients, demonstrating the potent immune stimulatory capacity of this generic vaccine. Furthermore, some patients reacted to peptide epitopes of antigens not expressed by the vaccine, showing that epitope-spreading occurred in vivo. Frequencies of nTregs and MDSCs were comparable to healthy donors at the beginning of study. A significant decrease of nTregs was detected after vaccination (p = 0.012). High immune response rates, decreased frequencies of nTregs and a mixed T helper 1/T helper 2 (T(H)1/T(H)2)-like cytokine pattern support the applicability of this RCC generic vaccine for use in combination therapies.
2017-02-16
2017-02-16
2013-02-08
Article
High immune response rates and decreased frequencies of regulatory T cells in metastatic renal cell carcinoma patients after tumor cell vaccination. 2013, 18:1499-508 Mol. Med.
1528-3658
23269976
10.2119/molmed.2012.00221
http://hdl.handle.net/10033/620827
Molecular medicine (Cambridge, Mass.)
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208392019-08-30T11:29:17Zcom_10033_620533col_10033_620534
Modification of uptake and subcellular distribution of doxorubicin by N-acylhydrazone residues as visualised by intrinsic fluorescence.
Effenberger-Neidnicht, Katharina
Breyer, Sandra
Mahal, Katharina
Sasse, Florenz
Schobert, Rainer
Doxorubicin (1) is commonly used in the treatment of a wide range of cancers. Some N-acylhydrazones of 1 were previously found to have an improved tumour and organ selectivity. In order to clarify the molecular basis for this effect, the cellular uptake into various cancer cells and the localisation in PtK(2) potoroo kidney cells of 1 and its N-acylhydrazones derived from heptadecanoic acid (2) and 11-(menthoxycarbonyl)undecanoic acid (3) were studied drawing on their intrinsic fluorescence.
2017-02-23
2017-02-23
2012-01
Article
Modification of uptake and subcellular distribution of doxorubicin by N-acylhydrazone residues as visualised by intrinsic fluorescence. 2012, 69 (1):85-90 Cancer Chemother. Pharmacol.
1432-0843
21607555
10.1007/s00280-011-1675-z
http://hdl.handle.net/10033/620839
Cancer chemotherapy and pharmacology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208282019-08-30T11:29:17Zcom_10033_620533col_10033_620534
Archazolid A-15-O-β-D-glucopyranoside and iso-archazolid B: potent V-ATPase inhibitory polyketides from the myxobacteria Cystobacter violaceus and Archangium gephyra.
Horstmann, Nicole
Essig, Sebastian
Bockelmann, Svenja
Wieczorek, Helmut
Huss, Markus
Sasse, Florenz
Menche, Dirk
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Two structurally novel analogues of the macrolides archazolids A and B, archazolid A-15-O-β-D-glucopyranoside (archazolid E, 5) and iso-archazolid B (archazolid F, 6), were isolated from the myxobacterium Cystobacter violaceus and Archangium gephyra, respectively. Macrolactone 5 represents the first 15-O-glycoside of the archazolids. iso-Archazolid B (6) incorporates a C-3 alkene and presents the first constitutional isomer reported for this natural product class. The structures of these polyketides were determined by spectroscopic analysis, in particular by HMBC, HMQC, and ROESY NMR investigations and by chemical degradation. iso-Archazolid B (6) demonstrated extremely high antiproliferative and V-ATPase inhibitory effects, with IC(50) values in the picomolar range, while only moderate activity was observed for glycoside 5. iso-Archazolid B presents the most potent archazolid known.
2017-02-17
2017-02-17
2011-05-27
Article
Archazolid A-15-O-β-D-glucopyranoside and iso-archazolid B: potent V-ATPase inhibitory polyketides from the myxobacteria Cystobacter violaceus and Archangium gephyra. 2011, 74 (5):1100-5 J. Nat. Prod.
1520-6025
21513292
10.1021/np200036v
http://hdl.handle.net/10033/620828
Journal of natural products
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208292019-08-30T11:34:22Zcom_10033_620533col_10033_620534
A selective 3-acylation of tetramic acids and the first synthesis of ravenic acid.
Schlenk, Andrea
Diestel, Randi
Sasse, Florenz
Schobert, Rainer
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
3-Acyltetramic acids, including delicate 3-oligoenoyl derivatives, such as the Penicillium metabolite ravenic acid, were prepared in two high-yielding steps. Reaction of tetramic acids with the ylide Ph(3)PCCO afforded exclusively the corresponding 3-acylylidenetetramic acids. These were amenable to Wittig olefinations with aliphatic, aromatic, saturated and unsaturated aldehydes after deprotonation with KOtBu. Due to its simplicity, selectivity and tolerance of pH-sensitive groups this method is superior to the established acylation protocols by Jones and Yoshii. It is also applicable to the synthesis of 3-acyltetronic acids. The new 3-oligoenoyl tetramic acids exhibited structure-dependent antimicrobial and cytotoxic activity.
2017-02-17
2017-02-17
2010-02-22
Article
A selective 3-acylation of tetramic acids and the first synthesis of ravenic acid. 2010, 16 (8):2599-604 Chemistry
1521-3765
20066698
10.1002/chem.200902544
http://hdl.handle.net/10033/620829
Chemistry (Weinheim an der Bergstrasse, Germany)
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208302019-08-30T11:29:17Zcom_10033_620533col_10033_620534
From binary to multivalued to continuous models: the lac operon as a case study.
Franke, Raimo
Theis, Fabian J
Klamt, Steffen
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Using the lac operon as a paradigmatic example for a gene regulatory system in prokaryotes, we demonstrate how qualitative knowledge can be initially captured using simple discrete (Boolean) models and then stepwise refined to multivalued logical models and finally to continuous (ODE) models. At all stages, signal transduction and transcriptional regulation is integrated in the model description. We first show the potential benefit of a discrete binary approach and discuss then problems and limitations due to indeterminacy arising in cyclic networks. These limitations can be partially circumvented by using multilevel logic as generalization of the Boolean framework enabling one to formulate a more realistic model of the lac operon. Ultimately a dynamic description is needed to fully appreciate the potential dynamic behavior that can be induced by regulatory feedback loops. As a very promising method we show how the use of multivariate polynomial interpolation allows transformation of the logical network into a system of ordinary differential equations (ODEs), which then enables the analysis of key features of the dynamic behavior.
2017-02-20
2017-02-20
2010-12-14
Article
From binary to multivalued to continuous models: the lac operon as a case study. 2010, 7 (1) J Integr Bioinform
1613-4516
21200084
10.2390/biecoll-jib-2010-151
http://hdl.handle.net/10033/620830
Journal of integrative bioinformatics
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6208312019-08-30T11:37:24Zcom_10033_620533col_10033_620534
Identification of a PA-binding peptide with inhibitory activity against influenza A and B virus replication.
Wunderlich, Kerstin
Mayer, Daniel
Ranadheera, Charlene
Holler, Anne-Sophie
Mänz, Benjamin
Martin, Arnold
Chase, Geoffrey
Tegge, Werner
Frank, Ronald
Kessler, Ulrich
Schwemmle, Martin
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
There is an urgent need for new drugs against influenza type A and B viruses due to incomplete protection by vaccines and the emergence of resistance to current antivirals. The influenza virus polymerase complex, consisting of the PB1, PB2 and PA subunits, represents a promising target for the development of new drugs. We have previously demonstrated the feasibility of targeting the protein-protein interaction domain between the PB1 and PA subunits of the polymerase complex of influenza A virus using a small peptide derived from the PA-binding domain of PB1. However, this influenza A virus-derived peptide did not affect influenza B virus polymerase activity. Here we report that the PA-binding domain of the polymerase subunit PB1 of influenza A and B viruses is highly conserved and that mutual amino acid exchange shows that they cannot be functionally exchanged with each other. Based on phylogenetic analysis and a novel biochemical ELISA-based screening approach, we were able to identify an influenza A-derived peptide with a single influenza B-specific amino acid substitution which efficiently binds to PA of both virus types. This dual-binding peptide blocked the viral polymerase activity and growth of both virus types. Our findings provide proof of principle that protein-protein interaction inhibitors can be generated against influenza A and B viruses. Furthermore, this dual-binding peptide, combined with our novel screening method, is a promising platform to identify new antiviral lead compounds.
2017-02-20
2017-02-20
2009-10-20
Article
Identification of a PA-binding peptide with inhibitory activity against influenza A and B virus replication. 2009, 4 (10):e7517 PLoS ONE
1932-6203
19841738
10.1371/journal.pone.0007517
http://hdl.handle.net/10033/620831
PloS one
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6209432019-08-30T11:33:57Zcom_10033_620533col_10033_620534
The myxobacterial metabolite Soraphen A inhibits HIV-1 by reducing virus production and altering virion composition.
Fleta-Soriano, Eric
Smutná, Katarína
Martinez, Javier P
Lorca Oró, Cristina
Sadiq, S Kashif
Mirambeau, Gilles
Lopez-Iglesias, Carmen
Bosch, Marta
Pol, Albert
Brönstrup, Mark
Diez, Juana
Meyerhans, Andreas
Helmholtz Centre of infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Soraphen A is a myxobacterial metabolite that blocks the acetyl-CoA carboxylase of the host, and was previously identified as a novel HIV inhibitor. Here we report that Soraphen A acts by reducing virus production and altering the gp120 virion content, impacting entry capacity and infectivity. These effects are partially reversed by addition of palmitic acid, suggesting inhibition of HIV Env palmitoylation as one of the mechanisms of antiviral action.
2017-06-14
2017-06-14
2017-05-22
Article
The myxobacterial metabolite Soraphen A inhibits HIV-1 by reducing virus production and altering virion composition. 2017 Antimicrob. Agents Chemother.
1098-6596
28533249
10.1128/AAC.00739-17
http://hdl.handle.net/10033/620943
Antimicrobial agents and chemotherapy
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6210052019-08-30T11:33:29Zcom_10033_620533col_10033_620534
Characteristics, chemical compositions and biological activities of propolis from Al-Bahah, Saudi Arabia.
Elnakady, Yasser A
Rushdi, Ahmed I
Franke, Raimo
Abutaha, Nael
Ebaid, Hossam
Baabbad, Mohannad
Omar, Mohamed O M
Al Ghamdi, Ahmad A
Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Propolis has been used to treat several diseases since ancient times, and is an important source of bioactive natural compounds and drug derivatives. These properties have kept the interest of investigators around the world, leading to the investigation of the chemical and biological properties and application of propolis. In this report, the chemical constituents that are responsible for the anticancer activities of propolis were analyzed. The propolis was sourced from Al-Baha in the southern part of the Kingdom of Saudi Arabia. Standard protocols for chemical fractionation and bioactivity-guided chemical analysis were used to identify the bio-active ethyl acetate fraction. The extraction was performed in methanol and then analyzed by gas chromatography-mass spectrometry (GC-MS). The major compounds are triterpenoids, with a relative concentration of 74.0%; steroids, with a relative concentration of 9.8%; and diterpenoids, with a relative concentration of 7.9%. The biological activity was characterized using different approaches and cell-based assays. Propolis was found to inhibit the proliferation of cancer cells in a concentration-dependent manner through apoptosis. Immunofluorescence staining with anti-α-tubulin antibodies and cell cycle analysis indicated that tubulin and/or microtubules are the cellular targets of the L-acetate fraction. This study demonstrates the importance of Saudi propolis as anti-cancer drug candidates.
2017-07-11
2017-07-11
2017-02-06
Article
Characteristics, chemical compositions and biological activities of propolis from Al-Bahah, Saudi Arabia. 2017, 7:41453 Sci Rep
2045-2322
28165013
10.1038/srep41453
http://hdl.handle.net/10033/621005
Scientific reports
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6210392019-08-30T11:37:44Zcom_10033_620533com_10033_620636com_10033_620644col_10033_620534col_10033_620637col_10033_620647
Use of Single-Frequency Impedance Spectroscopy to Characterize the Growth Dynamics of Biofilm Formation in Pseudomonas aeruginosa.
van Duuren, Jozef B J H
Müsken, Mathias
Karge, Bianka
Tomasch, Jürgen
Wittmann, Christoph
Häussler, Susanne
Brönstrup, Mark
Impedance spectroscopy has been applied in prokaryotic and eukaryotic cytometry as a label-free method for the investigation of adherent cells. In this paper, its use for characterizing the growth dynamics of P. aeruginosa biofilms is described and compared to crystal violet staining and confocal microscopy. The method allows monitoring the growth of biofilm-forming P. aeruginosa in a continuous and label-free manner over a period of 72 h in a 96 well plate format. Impedance curves obtained for P. aeruginosa PA14 wild type and mutant strains with a transposon insertion in pqsA and pelA genes exhibited distinct phases. We propose that the slope of the declining curve following a maximum at ca. 35-40 h is a measure of biofilm formation. Transplant experiments with P. aeruginosa biofilms and paraffin suggest that the impedance also reflects pellicle formation at the liquid-air interface, a barely considered contributor to impedance. Finally, the impairment of biofilm formation upon treatment of cultures with L-arginine and with ciprofloxacin, tobramycin and meropenem was studied by single frequency impedance spectroscopy. We suggest that these findings qualify impedance spectroscopy as an additional technique to characterize biofilm formation and its modulation by small molecule drugs.
2017-08-03
2017-08-03
2017-07-12
Article
Use of Single-Frequency Impedance Spectroscopy to Characterize the Growth Dynamics of Biofilm Formation in Pseudomonas aeruginosa. 2017, 7 (1):5223 Sci Rep
2045-2322
28701712
10.1038/s41598-017-05273-5
http://hdl.handle.net/10033/621039
Scientific reports
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6210482019-08-30T11:27:16Zcom_10033_620533col_10033_620534
Isolation, Co-Crystallization and Structure-Based Characterization of Anabaenopeptins as Highly Potent Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa).
Schreuder, Herman
Liesum, Alexander
Lönze, Petra
Stump, Heike
Hoffmann, Holger
Schiell, Matthias
Kurz, Michael
Toti, Luigi
Bauer, Armin
Kallus, Christopher
Klemke-Jahn, Christine
Czech, Jörg
Kramer, Dan
Enke, Heike
Niedermeyer, Timo H J
Morrison, Vincent
Kumar, Vasant
Brönstrup, Mark
Helmholtz Centre of infection research, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Mature thrombin activatable fibrinolysis inhibitor (TAFIa) is a carboxypeptidase that stabilizes fibrin clots by removing C-terminal arginines and lysines from partially degraded fibrin. Inhibition of TAFIa stimulates the degradation of fibrin clots and may help to prevent thrombosis. Applying a lead finding approach based on literature-mining, we discovered that anabaenopeptins, cyclic peptides produced by cyanobacteria, were potent inhibitors of TAFIa with IC50 values as low as 1.5 nM. We describe the isolation and structure elucidation of 20 anabaenopeptins, including 13 novel congeners, as well as their pronounced structure-activity relationships (SAR) with respect to inhibition of TAFIa. Crystal structures of the anabaenopeptins B, C and F bound to the surrogate protease carboxypeptidase B revealed the binding modes of these large (~850 Da) compounds in detail and explained the observed SAR, i.e. the strong dependence of the potency on a basic (Arg, Lys) exocyclic residue that addressed the S1' binding pocket, and a broad tolerance towards substitutions in the pentacyclic ring that acted as a plug of the active site.
2017-08-04
2017-08-04
2016-09-08
Article
Isolation, Co-Crystallization and Structure-Based Characterization of Anabaenopeptins as Highly Potent Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa). 2016, 6:32958 Sci Rep
2045-2322
27604544
10.1038/srep32958
http://hdl.handle.net/10033/621048
Scientific reports
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6210952019-08-30T11:33:04Zcom_10033_620533col_10033_620534
Olfaction, taste and chemoreception: scientific evidence replaces "Essays in biopoetry".
Appendino, Giovanni
Brönstrup, Mark
Kubanek, Julia M
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
2017-09-07
2017-09-07
2017
Article
Olfaction, taste and chemoreception: scientific evidence replaces "Essays in biopoetry". 2017, 34 (5):469-471 Nat Prod Rep
1460-4752
28485741
10.1039/c7np90016c
http://hdl.handle.net/10033/621095
Natural product reports
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6211342019-08-30T11:26:42Zcom_10033_620533col_10033_620534
The Kaposi's sarcoma-associated herpesvirus (KSHV) non-structural membrane protein K15 is required for viral lytic replication and may represent a therapeutic target.
Abere, Bizunesh
Mamo, Tamrat M
Hartmann, Silke
Samarina, Naira
Hage, Elias
Rückert, Jessica
Hotop, Sven-Kevin
Büsche, Guntram
Schulz, Thomas F
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Kaposi's sarcoma-associated herpesvirus (KSHV) is the infectious cause of the highly vascularized tumor Kaposi's sarcoma (KS), which is characterized by proliferating spindle cells of endothelial origin, extensive neo-angiogenesis and inflammatory infiltrates. The KSHV K15 protein contributes to the angiogenic and invasive properties of KSHV-infected endothelial cells. Here, we asked whether K15 could also play a role in KSHV lytic replication. Deletion of the K15 gene from the viral genome or its depletion by siRNA lead to reduced virus reactivation, as evidenced by the decreased expression levels of KSHV lytic proteins RTA, K-bZIP, ORF 45 and K8.1 as well as reduced release of infectious virus. Similar results were found for a K1 deletion virus. Deleting either K15 or K1 from the viral genome also compromised the ability of KSHV to activate PLCγ1, Erk1/2 and Akt1. In infected primary lymphatic endothelial (LEC-rKSHV) cells, which have previously been shown to spontaneously display a viral lytic transcription pattern, transfection of siRNA against K15, but not K1, abolished viral lytic replication as well as KSHV-induced spindle cell formation. Using a newly generated monoclonal antibody to K15, we found an abundant K15 protein expression in KS tumor biopsies obtained from HIV positive patients, emphasizing the physiological relevance of our findings. Finally, we used a dominant negative inhibitor of the K15-PLCγ1 interaction to establish proof of principle that pharmacological intervention with K15-dependent pathways may represent a novel approach to block KSHV reactivation and thereby its pathogenesis.
2017-10-11
2017-10-11
2017-09
Article
The Kaposi's sarcoma-associated herpesvirus (KSHV) non-structural membrane protein K15 is required for viral lytic replication and may represent a therapeutic target. 2017, 13 (9):e1006639 PLoS Pathog.
1553-7374
28938025
10.1371/journal.ppat.1006639
http://hdl.handle.net/10033/621134
PLoS pathogens
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6211582019-08-30T11:37:44Zcom_10033_620533col_10033_620534
Multivalent Siderophore-DOTAM Conjugates as Theranostics for Imaging and Treatment of Bacterial Infections.
Ferreira, Kevin
Hu, Hai-Yu
Fetz, Verena
Prochnow, Hans
Rais, Bushra
Müller, Peter P
Brönstrup, Mark
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr.7, 38124 Braunschweig, Germany.
There is a strong need to better diagnose infections at deep body sites through noninvasive molecular imaging methods. Herein, we describe the synthesis and characterization of probes based on siderophore conjugates with catechol moieties and a central DOTAM scaffold. The probes can accommodate a metal ion as well as an antibiotic moiety and are therefore suited for theranostic purposes. The translocation of the conjugates across the outer and inner cell membranes of E. coli was confirmed by growth recovery experiments with enterobactin-deficient strains, by the antibacterial activity of ampicillin conjugates, and by confocal imaging using a fluorogen-activating protein-malachite green system adapted to E. coli. The suitability of the probes for in vivo imaging was demonstrated with a Cy5.5 conjugate in mice infected with P. aeruginosa.
2017-11-03
2017-11-03
2017-07-03
Article
Multivalent Siderophore-DOTAM Conjugates as Theranostics for Imaging and Treatment of Bacterial Infections. 2017, 56 (28):8272-8276 Angew. Chem. Int. Ed. Engl.
1521-3773
28608939
10.1002/anie.201701358
http://hdl.handle.net/10033/621158
Angewandte Chemie (International ed. in English)
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6211842019-08-30T11:25:11Zcom_10033_620533com_10033_311308com_10033_620618col_10033_620534col_10033_620619col_10033_559591
Biosynthesis of methyl-proline containing griselimycins, natural products with anti-tuberculosis activity.
Lukat, Peer
Katsuyama, Yohei
Wenzel, Silke
Binz, Tina
König, Claudia
Blankenfeldt, Wulf
Brönstrup, Mark
Müller, Rolf
Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany.
Griselimycins (GMs) are depsidecapeptides with superb anti-tuberculosis activity. They contain up to three (2S,4R)-4-methyl-prolines (4-MePro), of which one blocks oxidative degradation and increases metabolic stability in animal models. The natural congener with this substitution is only a minor component in fermentation cultures. We showed that this product can be significantly increased by feeding the reaction with 4-MePro and we investigated the molecular basis of 4-MePro biosynthesis and incorporation. We identified the GM biosynthetic gene cluster as encoding a nonribosomal peptide synthetase and a sub-operon for 4-MePro formation. Using heterologous expression, gene inactivation, and in vitro experiments, we showed that 4-MePro is generated by leucine hydroxylation, oxidation to an aldehyde, and ring closure with subsequent reduction. The crystal structures of the leucine hydroxylase GriE have been determined in complex with substrates and products, providing insight into the stereospecificity of the reaction.
2017-11-27
2017-11-27
2017-11-01
Article
Biosynthesis of methyl-proline containing griselimycins, natural products with anti-tuberculosis activity. 2017, 8 (11):7521-7527 Chem Sci
2041-6520
29163906
10.1039/c7sc02622f
http://hdl.handle.net/10033/621184
Chemical science
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6212792019-08-30T11:35:14Zcom_10033_620533col_10033_620534
The CLU-files: disentanglement of a mystery.
Rohne, Philipp
Prochnow, Hans
Koch-Brandt, Claudia
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunshweig, Germany.
The multifaceted protein clusterin (CLU) has been challenging researchers for more than 35 years. The characterization of CLU as a molecular chaperone was one of the major breakthroughs in CLU research. Today, secretory clusterin (sCLU), also known as apolipoprotein J (apoJ), is considered one of the most important extracellular chaperones ever found. It is involved in a broad range of physiological and pathophysiological functions, where it exerts a cytoprotective role. Descriptions of various forms of intracellular CLU have led to further and even contradictory functions. To untangle the current state of knowledge of CLU, this review will combine old views in the field, with new discoveries to highlight the nature and function of this fascinating protein(s). In this review, we further describe the expression and subcellular location of various CLU forms. Moreover, we discuss recent insights into the structure of CLU and assess how structural properties as well as the redox environment determine the chaperone activity of CLU. Eventually, the review connects the biochemistry and molecular cell biology of CLU with medical aspects, to formulate a hypothesis of a CLU function in health and disease.
2018-02-15
2018-02-15
2016-02
Article
The CLU-files: disentanglement of a mystery. 2016, 7 (1):1-15 Biomol Concepts
1868-503X
26673020
10.1515/bmc-2015-0026
http://hdl.handle.net/10033/621279
Biomolecular concepts
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6212822019-08-30T11:26:42Zcom_10033_620533col_10033_620534
Synthesis of the AB ring system of clifednamide utilizing Claisen rearrangement and Diels-Alder reaction as key steps.
Loke, Inga
Bentzinger, Guillaume
Holz, Julia
Raja, Aruna
Bhasin, Aman
Sasse, Florenz
Köhn, Andreas
Schobert, Rainer
Laschat, Sabine
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
In order to construct the functionalized AB ring system of clifednamide, member of the class of macrocyclic tetramic acid lactams, a synthesis was developed which utilized an Ireland-Claisen rearrangement and an intramolecular Diels-Alder reaction. Starting from di-O-isopropylidene-d-mannitol the allyl carboxylate precursor for the sigmatropic rearrangement was prepared. This rearrangement proceeded diastereoselectively only in the presence of an allyl silyl ether instead of the parent enone in the side chain, as suggested by deuteration experiments. A subsequent Diels-Alder reaction yielded the target ethyl hexahydro-1H-indene-carboxylate with high diastereoselectivity. Quantum-chemical investigations of this intramolecular Diels-Alder reaction support the proposed configuration of the final product.
2018-02-16
2018-02-16
2016-01-21
Article
Synthesis of the AB ring system of clifednamide utilizing Claisen rearrangement and Diels-Alder reaction as key steps. 2016, 14 (3):884-94 Org. Biomol. Chem.
1477-0539
26599642
10.1039/c5ob01491c
http://hdl.handle.net/10033/621282
Organic & biomolecular chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6212832019-08-30T11:33:30Zcom_10033_620533col_10033_620534
Target identification by image analysis.
Fetz, V
Prochnow, H
Brönstrup, Mark
Sasse, F
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Covering: 1997 to the end of 2015Each biologically active compound induces phenotypic changes in target cells that are characteristic for its mode of action. These phenotypic alterations can be directly observed under the microscope or made visible by labelling structural elements or selected proteins of the cells with dyes. A comparison of the cellular phenotype induced by a compound of interest with the phenotypes of reference compounds with known cellular targets allows predicting its mode of action. While this approach has been successfully applied to the characterization of natural products based on a visual inspection of images, recent studies used automated microscopy and analysis software to increase speed and to reduce subjective interpretation. In this review, we give a general outline of the workflow for manual and automated image analysis, and we highlight natural products whose bacterial and eucaryotic targets could be identified through such approaches.
2018-02-16
2018-02-16
2016
Article
Target identification by image analysis. 2016, 33 (5):655-67 Nat Prod Rep
1460-4752
26777141
10.1039/c5np00113g
http://hdl.handle.net/10033/621283
Natural product reports
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6213152019-08-30T11:27:46Zcom_10033_620533col_10033_620534
A multi-target caffeine derived rhodium(i) N-heterocyclic carbene complex: evaluation of the mechanism of action.
Zhang, Jing-Jing
Muenzner, Julienne K
Abu El Maaty, Mohamed A
Karge, Bianka
Schobert, Rainer
Wölfl, Stefan
Ott, Ingo
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
A rhodium(i) and a ruthenium(ii) complex with a caffeine derived N-heterocyclic carbene (NHC) ligand were biologically investigated as organometallic conjugates consisting of a metal center and a naturally occurring moiety. While the ruthenium(ii) complex was largely inactive, the rhodium(i) NHC complex displayed selective cytotoxicity and significant anti-metastatic and in vivo anti-vascular activities and acted as both a mammalian and an E. coli thioredoxin reductase inhibitor. In HCT-116 cells it increased the reactive oxygen species level, leading to DNA damage, and it induced cell cycle arrest, decreased the mitochondrial membrane potential, and triggered apoptosis. This rhodium(i) NHC derivative thus represents a multi-target compound with promising anti-cancer potential.
2018-03-08
2018-03-08
2016-08-16
Article
A multi-target caffeine derived rhodium(i) N-heterocyclic carbene complex: evaluation of the mechanism of action. 2016, 45 (33):13161-8 Dalton Trans
1477-9234
27334935
10.1039/c6dt02025a
http://hdl.handle.net/10033/621315
Dalton transactions (Cambridge, England : 2003)
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6213602019-08-30T11:33:57Zcom_10033_620533com_10033_311624com_10033_6839com_10033_338554col_10033_621787col_10033_620534col_10033_311625
Differential magnesium implant corrosion coat formation and contribution to bone bonding.
Rahim, Muhammad Imran
Weizbauer, Andreas
Evertz, Florian
Hoffmann, Andrea
Rohde, M
Glasmacher, Birgit
Windhagen, Henning
Gross, Gerhard
Seitz, Jan-Marten
Mueller, Peter P
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Magnesium alloys are presently under investigation as promising biodegradable implant materials with osteoconductive properties. To study the molecular mechanisms involved, the potential contribution of soluble magnesium corrosion products to the stimulation of osteoblastic cell differentiation was examined. However, no evidence for the stimulation of osteoblast differentiation could be obtained when cultured mesenchymal precursor cells were differentiated in the presence of metallic magnesium or in cell culture medium containing elevated magnesium ion levels. Similarly, in soft tissue no bone induction by metallic magnesium or by the corrosion product magnesium hydroxide could be observed in a mouse model. Motivated by the comparatively rapid accumulation solid corrosion products physicochemical processes were examined as an alternative mechanism to explain the stimulation of bone growth by magnesium-based implants. During exposure to physiological solutions a structured corrosion coat formed on magnesium whereby the elements calcium and phosphate were enriched in the outermost layer which could play a role in the established biocompatible behavior of magnesium implants. When magnesium pins were inserted into avital bones, corrosion lead to increases in the pull out force, suggesting that the expanding corrosion layer was interlocking with the surrounding bone. Since mechanical stress is a well-established inducer of bone growth, volume increases caused by the rapid accumulation of corrosion products and the resulting force development could be a key mechanism and provide an explanation for the observed stimulatory effects of magnesium-based implants in hard tissue. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 697-709, 2017.
2018-04-24
2018-04-24
2017
Article
Differential magnesium implant corrosion coat formation and contribution to bone bonding. 2017, 105 (3):697-709 J Biomed Mater Res A
1552-4965
27770566
10.1002/jbm.a.35943
http://hdl.handle.net/10033/621360
Journal of biomedical materials research. Part A
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
oai:repository.helmholtz-hzi.de:10033/6214202019-08-30T11:33:01Zcom_10033_620533col_10033_620534
Occupation-Associated Fatal Limbic Encephalitis Caused by Variegated Squirrel Bornavirus 1, Germany, 2013.
Tappe, Dennis
Schlottau, Kore
Cadar, Daniel
Hoffmann, Bernd
Balke, Lorenz
Bewig, Burkhard
Hoffmann, Donata
Eisermann, Philip
Fickenscher, Helmut
Krumbholz, Andi
Laufs, Helmut
Huhndorf, Monika
Rosenthal, Maria
Schulz-Schaeffer, Walter
Ismer, Gabriele
Hotop, Sven-Kevin
Brönstrup, Mark
Ott, Anthonina
Schmidt-Chanasit, Jonas
Beer, Martin
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Bornavirus
Germany
VSBV-1
limbic encephalitis
occupational risk
squirrel
transmission
variegated squirrel bornavirus 1
viruses
zoonoses
Limbic encephalitis is commonly regarded as an autoimmune-mediated disease. However, after the recent detection of zoonotic variegated squirrel bornavirus 1 in a Prevost's squirrel (Callosciurus prevostii) in a zoo in northern Germany, we retrospectively investigated a fatal case in an autoantibody-seronegative animal caretaker who had worked at that zoo. The virus had been discovered in 2015 as the cause of a cluster of cases of fatal encephalitis among breeders of variegated squirrels (Sciurus variegatoides) in eastern Germany. Molecular assays and immunohistochemistry detected a limbic distribution of the virus in brain tissue of the animal caretaker. Phylogenetic analyses demonstrated a spillover infection from the Prevost's squirrel. Antibodies against bornaviruses were detected in the patient's cerebrospinal fluid by immunofluorescence and newly developed ELISAs and immunoblot. The putative antigenic epitope was identified on the viral nucleoprotein. Other zoo workers were not infected; however, avoidance of direct contact with exotic squirrels and screening of squirrels are recommended.
2018-07-04
2018-07-04
2018-06-01
Article
1080-6059
29774846
10.3201/eid2406.172027
http://hdl.handle.net/10033/621420
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:repository.helmholtz-hzi.de:10033/6214412019-08-30T11:31:46Zcom_10033_620533col_10033_620534
A modular synthesis of tetracyclic meroterpenoid antibiotics
Wildermuth, Raphael
Speck, Klaus
Haut, Franz-Lucas
Mayer, Peter
Karge, Bianka
Brönstrup, Mark
Magauer, Thomas
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
2018-08-08
2018-08-08
Article
2041-1723
10.1038/s41467-017-02061-7
http://hdl.handle.net/10033/621441
http://www.nature.com/articles/s41467-017-02061-7
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:repository.helmholtz-hzi.de:10033/6214542019-08-30T11:29:14Zcom_10033_620533col_10033_620534
Detection and Investigation of Eagle Effect Resistance to Vancomycin in With an ATP-Bioluminescence Assay.
Jarrad, Angie M
Blaskovich, Mark A T
Prasetyoputri, Anggia
Karoli, Tomislav
Hansford, Karl A
Cooper, Matthew A
Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
ATP-bioluminescence
Clostridium difficile
Eagle effect
antibiotic resistance
vancomycin
Vancomycin was bactericidal against Clostridium difficile at eightfold the minimum inhibitory concentration (MIC) using a traditional minimum bactericidal concentration (MBC) assay. However, at higher concentrations up to 64 × MIC, vancomycin displayed a paradoxical “more-drug-kills-less” Eagle effect against C. difficile. To overcome challenges associated with performing the labor-intensive agar-based MBC method under anaerobic growth conditions, we investigated an alternative more convenient ATP-bioluminescence assay to assess the Eagle effect in C. difficile. The commercial BacTiter-GloTM assay is a homogenous method to determine bacterial viability based on quantification of bacterial ATP as a marker for metabolic activity. The ATP-bioluminescence assay was advantageous over the traditional MBC-type assay in detecting the Eagle effect because it reduced assay time and was simple to perform; measurement of viability could be performed in less than 10 min outside of the anaerobic chamber. Using this method, we found C. difficile survived clinically relevant, high concentrations of vancomycin (up to 2048 μg/mL). In contrast, C. difficile did not survive high concentrations of metronidazole or fidaxomicin. The Eagle effect was also detected for telavancin, but not for teicoplanin, dalbavancin, oritavancin, or ramoplanin. All four pathogenic strains of C. difficile tested consistently displayed Eagle effect resistance to vancomycin, but not metronidazole or fidaxomicin. These results suggest that Eagle effect resistance to vancomycin in C. difficile could be more prevalent than previously appreciated, with potential clinical implications. The ATP-Bioluminescence assay can thus be used as an alternative to the agar-based MBC assay to characterize the Eagle effect against a variety of antibiotics, at a wide-range of concentrations, with much greater throughput. This may facilitate improved understanding of Eagle effect resistance and promote further research to understand potential clinical relevance.
2018-08-27
2018-08-27
2018-01-01
Article
1664-302X
30013531
10.3389/fmicb.2018.01420
http://hdl.handle.net/10033/621454
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Attribution-NonCommercial-ShareAlike 3.0 United States
oai:repository.helmholtz-hzi.de:10033/6216342019-08-30T11:31:21Zcom_10033_620533com_10033_311308col_10033_620534col_10033_620777col_10033_559591
Investigations on the mode of action of gephyronic acid, an inhibitor of eukaryotic protein translation from myxobacteria.
Muthukumar, Yazh
Münkemer, Johanna
Mathieu, Daniel
Richter, Christian
Schwalbe, Harald
Steinmetz, Heinrich
Kessler, Wolfgang
Reichelt, Joachim
Beutling, Ulrike
Frank, Ronald
Büssow, Konrad
van den Heuvel, Joop
Brönstrup, Mark
Taylor, Richard E
LASCHAT, SABINE
Sasse, Florenz
The identification of inhibitors of eukaryotic protein biosynthesis, which are targeting single translation factors, is highly demanded. Here we report on a small molecule inhibitor, gephyronic acid, isolated from the myxobacterium Archangium gephyra that inhibits growth of transformed mammalian cell lines in the nM range. In direct comparison, primary human fibroblasts were shown to be less sensitive to toxic effects of gephyronic acid than cancer-derived cells. Gephyronic acid is targeting the protein translation system. Experiments with IRES dual luciferase reporter assays identified it as an inhibitor of the translation initiation. DARTs approaches, co-localization studies and pull-down assays indicate that the binding partner could be the eukaryotic initiation factor 2 subunit alpha (eIF2α). Gephyronic acid seems to have a different mode of action than the structurally related polyketides tedanolide, myriaporone, and pederin and is a valuable tool for investigating the eukaryotic translation system. Because cancer derived cells were found to be especially sensitive, gephyronic acid could potentially find use as a drug candidate.
2019-01-07
2019-01-07
2018-01-01
Article
PLoS One. 2018 Jul 31;13(7):e0201605. doi: 10.1371/journal.pone.0201605 eCollection 2018.
1932-6203
30063768
10.1371/journal.pone.0201605
http://hdl.handle.net/10033/621634
PLOSOne
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
PLOS
oai:repository.helmholtz-hzi.de:10033/6216362019-11-21T11:58:00Zcom_10033_620533com_10033_620652col_10033_620672col_10033_620534
Advances and Challenges of Biodegradable Implant Materials with a Focus on Magnesium-Alloys and Bacterial Infections
Rahim, Muhammad
Ullah, Sami
Mueller, Peter
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Medical implants made of biodegradable materials could be advantageous for temporary applications, such as mechanical support during bone-healing or as vascular stents to keep blood vessels open. After completion of the healing process, the implant would disappear, avoiding long-term side effects or the need for surgical removal. Various corrodible metal alloys based on magnesium, iron or zinc have been proposed as sturdier and potentially less inflammatory alternatives to degradable organic polymers, in particular for load-bearing applications. Despite the recent introduction of magnesium-based screws, the remaining hurdles to routine clinical applications are still challenging. These include limitations such as mechanical material characteristics or unsuitable corrosion characteristics. In this article, the salient features and clinical prospects of currently-investigated biodegradable implant materials are summarized, with a main focus on magnesium alloys. A mechanism of action for the stimulation of bone growth due to the exertion of mechanical force by magnesium corrosion products is discussed. To explain divergent in vitro and in vivo effects of magnesium, a novel model for bacterial biofilm infections is proposed which predicts crucial consequences for antibacterial implant strategies.
2019-01-09
2019-01-09
2018-07-10
Article
2075-4701
10.3390/met8070532
http://hdl.handle.net/10033/621636
Metals
http://www.mdpi.com/2075-4701/8/7/532
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
MPDI
oai:repository.helmholtz-hzi.de:10033/6216832019-08-30T11:33:04Zcom_10033_620533com_10033_338554com_10033_311308col_10033_620534col_10033_620721col_10033_338544
xCELLanalyzer: A Framework for the Analysis of Cellular Impedance Measurements for Mode of Action Discovery
Franke, Raimo
Hinkelmann, Bettina
Fetz, Verena
Stradal, Theresia
Sasse, Florenz
Klawonn, Frank
Brönstrup, Mark
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
mode of action
impedance spectroscopy
target identification
natural products
actinomycin D
Mode of action (MoA) identification of bioactive compounds is very often a challenging and time-consuming task. We used a label-free kinetic profiling method based on an impedance readout to monitor the time-dependent cellular response profiles for the interaction of bioactive natural products and other small molecules with mammalian cells. Such approaches have been rarely used so far due to the lack of data mining tools to properly capture the characteristics of the impedance curves. We developed a data analysis pipeline for the xCELLigence Real-Time Cell Analysis detection platform to process the data, assess and score their reproducibility, and provide rank-based MoA predictions for a reference set of 60 bioactive compounds. The method can reveal additional, previously unknown targets, as exemplified by the identification of tubulin-destabilizing activities of the RNA synthesis inhibitor actinomycin D and the effects on DNA replication of vioprolide A. The data analysis pipeline is based on the statistical programming language R and is available to the scientific community through a GitHub repository.
2019-02-12
2019-02-12
2019-01-25
Article
2472-5552
2472-5560
30681906
10.1177/2472555218819459
http://hdl.handle.net/10033/621683
SLAS Discovery
http://journals.sagepub.com/doi/10.1177/2472555218819459
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Sage
oai:repository.helmholtz-hzi.de:10033/6216842019-08-30T11:33:04Zcom_10033_620533com_10033_620636col_10033_620534col_10033_620637
Identification and quantification of (t)RNA modifications in Pseudomonas aeruginosa by liquid chromatography-tandem mass spectrometry.
Grobe, Svenja
Doberenz, Sebastian
Ferreira, Kevin
Krueger, Jonas
Brönstrup, Mark
Kaever, Volkhard
Häußler, Susanne
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Mass spectrometry
Pseudomonas aeruginosa
tRNA
tRNA modifications
Transfer RNA (tRNA) modifications impact the structure and function of tRNAs thus affecting the efficiency and fidelity of translation. In the opportunistic pathogen Pseudomonas aeruginosa translational regulation plays an important but less defined role in the adaptation to changing environments. In this study, we explored tRNA modifications in P. aeruginosa using LC-MS/MS based approaches. Neutral Loss Scan (NLS) demonstrated the potential to identify previously unknown modifications, while Multiple Reaction Monitoring (MRM) can detect modifications with high specificity and sensitivity. In this study, the MRM-based external calibration method allowed for quantification of the 4 canonical and 32 modified ribonucleosides, of which 21 tRNA modifications were quantified in the total tRNA pool of P. aeruginosa PA14. We also purified the single tRNA isoacceptors tRNA-ArgUCU, tRNA-LeuCAA and tRNA-TrpCCA and determined, both qualitatively and quantitatively, their specific modification pattern. Deeper insights into the nature and dynamics of tRNA modifications in P. aeruginosa will pave the way for further studies on posttranscriptional gene regulation as a relatively unexplored molecular mechanism of controlling bacterial pathogenicity and life style.
2019-02-12
2019-02-12
2019-01-15
Article
Chembiochem. 2019 Jan 15. doi: 10.1002/cbic.201800741
1439-7633
30644616
10.1002/cbic.201800741
http://hdl.handle.net/10033/621684
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Wiley-Blackwell
oai:repository.helmholtz-hzi.de:10033/6216882019-08-30T11:32:39Zcom_10033_620533com_10033_620644col_10033_620534col_10033_620646
Metabolome and transcriptome-wide effects of the carbon storage regulator A in enteropathogenic Escherichia coli.
Berndt, Volker
Beckstette, Michael
Volk, Marcel
Dersch, Petra
Brönstrup, Mark
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
The carbon storage regulator A (CsrA) is a conserved global regulatory system known to control central carbon pathways, biofilm formation, motility, and pathogenicity. The aim of this study was to characterize changes in major metabolic pathways induced by CsrA in human enteropathogenic Escherichia coli (EPEC) grown under virulence factor-inducing conditions. For this purpose, the metabolomes and transcriptomes of EPEC and an isogenic ∆csrA mutant derivative were analyzed by untargeted mass spectrometry and RNA sequencing, respectively. Of the 159 metabolites identified from untargeted GC/MS and LC/MS data, 97 were significantly (fold change ≥ 1.5; corrected p-value ≤ 0.05) regulated between the knockout and the wildtype strain. A lack of csrA led to an accumulation of fructose-6-phosphate (F6P) and glycogen synthesis pathway products, whereas metabolites in lower glycolysis and the citric acid cycle were downregulated. Associated pathways from the citric acid cycle like aromatic amino acid and siderophore biosynthesis were also negatively influenced. The nucleoside salvage pathways were featured by an accumulation of nucleosides and nucleobases, and a downregulation of nucleotides. In addition, a pronounced downregulation of lyso-lipid metabolites was observed. A drastic change in the morphology in the form of vesicle-like structures of the ∆csrA knockout strain was visible by electron microscopy. Colanic acid synthesis genes were strongly (up to 50 fold) upregulated, and the abundance of colanic acid was 3 fold increased according to a colorimetric assay. The findings expand the scope of pathways affected by the csrA regulon and emphasize its importance as a global regulator.
2019-02-14
2019-02-14
2019-01-15
Article
2045-2322
30644424
10.1038/s41598-018-36932-w
http://hdl.handle.net/10033/621688
Scientific Reports
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Springer-Nature
oai:repository.helmholtz-hzi.de:10033/6217092019-08-30T11:34:21Zcom_10033_620533col_10033_620534
Subcellular Quantification of Uptake in Gram-Negative Bacteria.
Prochnow, Hans
Fetz, Verena
Hotop, Sven-Kevin
García-Rivera, Mariel A
Heumann, Axel
Brönstrup, Mark
HZI, Helmholtz Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig Germany.
Infections by Gram-negative pathogens represent a major health care issue of growing concern due to a striking lack of novel antibacterial agents over the course of the last decades. The main scientific problem behind the rational optimization of novel antibiotics is our limited understanding of small molecule translocation into, and their export from, the target compartments of Gram-negative species. To address this issue, a versatile, label-free assay to determine the intracellular localization and concentration of a given compound has been developed for Escherichia coli and its efflux-impaired ΔTolC mutant. The assay applies a fractionation procedure to antibiotic-treated bacterial cells to obtain periplasm, cytoplasm, and membrane fractions of high purity, as demonstrated by Western Blots of compartment-specific marker proteins. This is followed by an LC-MS/MS-based quantification of antibiotic content in each compartment. Antibiotic amounts could be converted to antibiotic concentrations by assuming that an E. coli cell is a cylinder flanked by two half spheres and calculating the volumes of bacterial compartments. The quantification of antibiotics from different classes, namely ciprofloxacin, tetracycline, trimethoprim, and erythromycin, demonstrated pronounced differences in uptake quantities and distribution patterns across the compartments. For example, in the case of ciprofloxacin, a higher amount of compound was located in the cytoplasm than in the periplasm (592 ± 50 pg vs 277 ± 13 pg per 3.9 × 10
2019-03-01
2019-03-01
2019-02-05
Article
Anal Chem. 2019 Feb 5;91(3):1863-1872. doi: 10.1021/acs.analchem.8b03586. Epub 2018 Nov 11
1520-6882
30485749
10.1021/acs.analchem.8b03586
http://hdl.handle.net/10033/621709
Analytical chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
ACS Publications
oai:repository.helmholtz-hzi.de:10033/6217212020-08-21T12:44:46Zcom_10033_620533col_10033_620534
Single-cell phenotypic characterization of Staphylococcus aureus with fluorescent triazole urea activity-based probes.
Chen, Linhai
Keller, Laura J
Cordasco, Edward A
Bogyo, Matthew
Lentz, Christian S
HZI, Helmholtz Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig Germany.
Activity-based protein profiling
Molecular Imaging
Phenotype
enzymes
single-cell analysis
Phenotypically distinct cellular (sub)populations are clinically relevant for virulence and antibiotic resistance of a bacterial pathogen, but functionally different cells are usually indistinguishable from each other. Here, we introduce fluorescent activity-based probes as chemical tools for single-cell phenotypic characterization of enzyme activity levels in Staphylococcus aureus. We screened a 1,2,3-triazole urea library to identify selective inhibitors of fluorophosphonate-binding serine hydrolases and lipases in S. aureus and synthesized target-selective activity-based probes. Molecular imaging and activity-based protein profiling studies with these probes revealed a dynamic network within this enzyme family involving compensatory regulation of specific family members and exposed single-cell phenotypic heterogeneity. We propose chemical probe labeling of enzymatic activities as a generalizable method for phenotyping of bacterial cells at the population and single-cell level.
2019-03-14
2019-03-14
2019-02-15
Article
Angew Chem Int Ed Engl. 2019 Feb 15. doi: 10.1002/anie.201900511.
1521-3773
30768830
10.1002/anie.201900511
http://hdl.handle.net/10033/621721
Angewandte Chemie - International Edition
PMC6456404
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Wiley-Blackwell
oai:repository.helmholtz-hzi.de:10033/6217602019-08-30T11:32:36Zcom_10033_620533col_10033_620534
Diagnosing Zika virus infection against a background of other flaviviruses: Studies in high resolution serological analysis.
Hansen, Sören
Hotop, Sven-Kevin
Faye, Oumar
Ndiaye, Oumar
Böhlken-Fascher, Susanne
Pessôa, Rodrigo
Hufert, Frank
Stahl-Hennig, Christiane
Frank, Ronald
Czerny, Claus-Peter
Schmidt-Chanasit, Jonas
Sanabani, Sabri S
Sall, Amadou A
Niedrig, Matthias
Brönstrup, Mark
Fritz, Hans-Joachim
Abd El Wahed, Ahmed
HZI, Helmholtz Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig Germany.
BACKGROUND:
Antibody-mediated targeting of regulatory T cell receptors such as CTLA-4 enhances antitumor immune responses against several cancer entities including malignant melanoma. Yet, therapeutic success in patients remains variable underscoring the need for novel combinatorial approaches.
METHODS:
Here we established a vaccination strategy that combines engagement of the nucleic acid-sensing pattern recognition receptor RIG-I, antigen and CTLA-4 blockade. We used in vitro transcribed 5'-triphosphorylated RNA (3pRNA) to therapeutically target the RIG-I pathway. We performed in vitro functional analysis in bone-marrow derived dendritic cells and investigated RIG-I-enhanced vaccines in different murine melanoma models.
FINDINGS:
We found that protein vaccination together with RIG-I ligation via 3pRNA strongly synergizes with CTLA-4 blockade to induce expansion and activation of antigen-specific CD8+ T cells that translates into potent antitumor immunity. RIG-I-induced cross-priming of cytotoxic T cells as well as antitumor immunity were dependent on the host adapter protein MAVS and type I interferon (IFN-I) signaling and were mediated by dendritic cells.
INTERPRETATION:
Overall, our data demonstrate the potency of a novel combinatorial vaccination strategy combining RIG-I-driven immunization with CTLA-4 blockade to prevent and treat experimental melanoma. FUND: German Research Foundation (SFB 1335, SFB 1371), EMBO, Else Kröner-Fresenius-Foundation, German Cancer Aid, European Hematology Association, DKMS Foundation for Giving Life, Dres. Carl Maximilian and Carl Manfred Bayer-Foundation.
2019-04-30
2019-04-30
2019-03-06
Article
Sci Rep. 2019 Mar 6;9(1):3648. doi: 10.1038/s41598-019-40224-2.
2045-2322
30842564
10.1038/s41598-019-40224-2
http://hdl.handle.net/10033/621760
Scientific Reports
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Springer-Nature
oai:repository.helmholtz-hzi.de:10033/6217902019-08-30T11:24:26Zcom_10033_620533col_10033_620534
Kaposi's sarcoma-associated herpesvirus vIRF2 protein utilizes an IFN-dependent pathway to regulate viral early gene expression.
Koch, Sandra
Damas, Modester
Freise, Anika
Hage, Elias
Dhingra, Akshay
Rückert, Jessica
Gallo, Antonio
Kremmer, Elisabeth
Tegge, Werner
Brönstrup, Mark
Brune, Wolfram
Schulz, Thomas F
HZI, Helmholtz Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
Kaposi's sarcoma-associated herpesvirus (KSHV; human herpesvirus 8) belongs to the subfamily of Gammaherpesvirinae and is the etiological agent of Kaposi's sarcoma as well as of two lymphoproliferative diseases: primary effusion lymphoma and multicentric Castleman disease. The KSHV life cycle is divided into a latent and a lytic phase and is highly regulated by viral immunomodulatory proteins which control the host antiviral immune response. Among them is a group of proteins with homology to cellular interferon regulatory factors, the viral interferon regulatory factors 1-4. The KSHV vIRFs are known as inhibitors of cellular interferon signaling and are involved in different oncogenic pathways. Here we characterized the role of the second vIRF protein, vIRF2, during the KSHV life cycle. We found the vIRF2 protein to be expressed in different KSHV positive cells with early lytic kinetics. Importantly, we observed that vIRF2 suppresses the expression of viral early lytic genes in both newly infected and reactivated persistently infected endothelial cells. This vIRF2-dependent regulation of the KSHV life cycle might involve the increased expression of cellular interferon-induced genes such as the IFIT proteins 1, 2 and 3, which antagonize the expression of early KSHV lytic proteins. Our findings suggest a model in which the viral protein vIRF2 allows KSHV to harness an IFN-dependent pathway to regulate KSHV early gene expression.
2019-05-21
2019-05-21
2019-05-01
Article
PLoS Pathog. 2019 May 6;15(5):e1007743. doi: 10.1371/journal.ppat.1007743. eCollection 2019 May.
1553-7374
31059555
10.1371/journal.ppat.1007743
http://hdl.handle.net/10033/621790
PLOS Pathogens
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
PLOS
oai:repository.helmholtz-hzi.de:10033/6218112019-08-30T11:37:20Zcom_10033_620533col_10033_620534
Von Willebrand Factor Mediates Pneumococcal Aggregation and Adhesion in Blood Flow.
Jagau, Hilger
Behrens, Ina-Kristin
Lahme, Karen
Lorz, Georgina
Köster, Reinhard W
Schneppenheim, Reinhard
Obser, Tobias
Brehm, Maria A
König, Gesa
Kohler, Thomas P
Rohde, Manfred
Frank, Ronald
Tegge, Werner
Fulde, Marcus
Hammerschmidt, Sven
Steinert, Michael
Bergmann, Simone
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Streptococcus pneumoniae
endothelium
enolase
von Willebrand factor
zebrafish
Streptococcus pneumoniae is a major cause of community acquired pneumonia and septicaemia in humans. These diseases are frequently associated with thromboembolic cardiovascular complications. Pneumococci induce the exocytosis of endothelial Weibel-Palade Bodies and thereby actively stimulate the release of von Willebrand factor (VWF), which is an essential glycoprotein of the vascular hemostasis. Both, the pneumococcus induced pulmonary inflammation and the thromboembolytic complications are characterized by a dysbalanced hemostasis including a marked increase in VWF plasma concentrations. Here, we describe for the first time VWF as a novel interaction partner of capsulated and non-encapsulated pneumococci. Moreover, cell culture infection analyses with primary endothelial cells characterized VWF as bridging molecule that mediates bacterial adherence to endothelial cells in a heparin-sensitive manner. Due to the mechanoresponsive changes of the VWF protein conformation and multimerization status, which occur in the blood stream, we used a microfluidic pump system to generate shear flow-induced multimeric VWF strings on endothelial cell surfaces and analyzed attachment of RFP-expressing pneumococci in flow. By applying immunofluorescence visualization and additional electron microscopy, we detected a frequent and enduring bacterial attachment to the VWF strings. Bacterial attachment to the endothelium was confirmed in vivo using a zebrafish infection model, which is described in many reports and acknowledged as suitable model to study hemostasis mechanisms and protein interactions of coagulation factors. Notably, we visualized the recruitment of zebrafish-derived VWF to the surface of pneumococci circulating in the blood stream and detected a VWF-dependent formation of bacterial aggregates within the vasculature of infected zebrafish larvae. Furthermore, we identified the surface-exposed bacterial enolase as pneumococcal VWF binding protein, which interacts with the VWF domain A1 and determined the binding kinetics by surface plasmon resonance. Subsequent epitope mapping using an enolase peptide array indicates that the peptide 181YGAEIFHALKKILKS195 might serve as a possible core sequence of the VWF interaction site. In conclusion, we describe a VWF-mediated mechanism for pneumococcal anchoring within the bloodstream via surface-displayed enolase, which promotes intravascular bacterial aggregation.
2019-06-11
2019-06-11
2019-01-01
Article
Front Microbiol. 2019 Mar 26;10:511. doi: 10.3389/fmicb.2019.00511. eCollection 2019.
1664-302X
30972039
10.3389/fmicb.2019.00511
http://hdl.handle.net/10033/621811
Frontiers in Microbiology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Frontiers
oai:repository.helmholtz-hzi.de:10033/6218392019-08-30T11:27:09Zcom_10033_620533col_10033_620534
New geldanamycin derivatives with anti Hsp properties by mutasynthesis.
Hermane, Jekaterina
Eichner, Simone
Mancuso, Lena
Schröder, Benjamin
Sasse, Florenz
Zeilinger, Carsten
Kirschning, Andreas
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Mutasynthetic supplementation of the AHBA blocked mutant strain of S. hygroscopicus, the geldanamycin producer, with 21 aromatic and heteroaromatic amino acids provided new nonquinoid geldanamycin derivatives. Large scale (5 L) fermentation provided four new derivatives in sufficient quantity for full structural characterisation. Among these, the first thiophene derivative of reblastatin showed strong antiproliferative activity towards several human cancer cell lines. Additionally, inhibitory effects on human heat shock protein Hsp90α and bacterial heat shock protein from H. pylori HpHtpG were observed, revealing strong displacement properties for labelled ATP and demonstrating that the ATP-binding site of Hsps is the target site for the new geldanamycin derivatives.
2019-07-02
2019-07-02
2019-05-29
Article
Org Biomol Chem. 2019 May 29;17(21):5269-5278. doi: 10.1039/c9ob00892f.
1477-0539
31089638
10.1039/c9ob00892f
http://hdl.handle.net/10033/621839
Organic and Biomolecular Chemistry
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Royal Society of Chemistry
oai:repository.helmholtz-hzi.de:10033/6218512019-08-30T11:24:28Zcom_10033_620533col_10033_620534
Species-Specific Conservation of Linear Antigenic Sites on Vaccinia Virus A27 Protein Homologs of Orthopoxviruses.
Ahsendorf, Henrike P
Gan, Li L
Eltom, Kamal H
Abd El Wahed, Ahmed
Hotop, Sven-Kevin
Roper, Rachel L
Beutling, Ulrike
Broenstrup, Mark
Stahl-Hennig, Christiane
Hoelzle, Ludwig E
Czerny, Claus-Peter
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Vaccinia virus A27 protein homologs
epitope mapping
neutralizing antibodies
phylogenetic epitope variation
The vaccinia virus (VACV) A27 protein and its homologs, which are found in a large number of members of the genus Orthopoxvirus (OPXV), are targets of viral neutralization by host antibodies. We have mapped six binding sites (epitopes #1A: aa 32-39, #1B: aa 28-33, #1C: aa 26-31, #1D: 28-34, #4: aa 9-14, and #5: aa 68-71) of A27 specific monoclonal antibodies (mAbs) using peptide arrays. MAbs recognizing epitopes #1A-D and #4 neutralized VACV Elstree in a complement dependent way (50% plaque-reduction: 12.5-200 µg/mL). Fusion of VACV at low pH was blocked through inhibition of epitope #1A. To determine the sequence variability of the six antigenic sites, 391 sequences of A27 protein homologs available were compared. Epitopes #4 and #5 were conserved among most of the OPXVs, while the sequential epitope complex #1A-D was more variable and, therefore, responsible for species-specific epitope characteristics. The accurate and reliable mapping of defined epitopes on immuno-protective proteins such as the A27 of VACV enables phylogenetic studies and insights into OPXV evolution as well as to pave the way to the development of safer vaccines and chemical or biological antivirals.
2019-07-08
2019-07-08
2019-05-29
Article
Viruses. 2019 May 29;11(6). pii: v11060493. doi: 10.3390/v11060493.
1999-4915
31146446
10.3390/v11060493
http://hdl.handle.net/10033/621851
Vioruses
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
MPDI
oai:repository.helmholtz-hzi.de:10033/6218572019-07-11T02:33:25Zcom_10033_620533com_10033_620652col_10033_620666col_10033_620534
Advances and Challenges of Biodegradable Implant Materials with a Focus on Magnesium-Alloys and Bacterial Infections
Rahim, Muhammad, I.
Sami, Ullah
Müller, Peter-Paul
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
bioresorbable implants
corrosion layer
orthopedic implants
microbial infections
Medical implants made of biodegradable materials could be advantageous for temporary applications, such as mechanical support during bone-healing or as vascular stents to keep blood vessels open. After completion of the healing process, the implant would disappear, avoiding long-term side effects or the need for surgical removal. Various corrodible metal alloys based on magnesium, iron or zinc have been proposed as sturdier and potentially less inflammatory alternatives to degradable organic polymers, in particular for load-bearing applications. Despite the recent introduction of magnesium-based screws, the remaining hurdles to routine clinical applications are still challenging. These include limitations such as mechanical material characteristics or unsuitable corrosion characteristics. In this article, the salient features and clinical prospects of currently-investigated biodegradable implant materials are summarized, with a main focus on magnesium alloys. A mechanism of action for the stimulation of bone growth due to the exertion of mechanical force by magnesium corrosion products is discussed. To explain divergent in vitro and in vivo effects of magnesium, a novel model for bacterial biofilm infections is proposed which predicts crucial consequences for antibacterial implant strategies.
2019-07-10
2019-07-10
2018-07-10
Article
2075-4701
10.3390/met8070532
http://hdl.handle.net/10033/621857
Metals
en
https://www.preprints.org/manuscript/201807.0016/v1
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
MPDI
oai:repository.helmholtz-hzi.de:10033/6218762019-08-30T11:24:28Zcom_10033_620533col_10033_620534
Firefly Bioluminescence-Based Detection of ATP
Jarrad, Angie M,
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Adenosine triphosphate (ATP) bioluminescence is a powerful light-producing phenomenon that occurs in nature in a variety of organisms, with ATP bioluminescence of fireflies one of the most well-known examples. The firefly ATP bioluminescence reaction has been adapted to the laboratory with a wide range of applications that include monitoring cellular processes, antimicrobial susceptibility testing, and the detection of bacterial contamination of environmental surfaces. ATP bioluminescence occurs through a multistep reaction between firefly luciferase, ATP, magnesium salt, and oxygen (Scheme 1).[1] As a simplified overview, luciferyl adenylate 2 is first formed from luciferin 1 and Mg2+-ATP. The luciferyl adenylate 2 is then oxidised with molecular oxygen to form a dioxetanone cyclic peroxide intermediate 3. Following intramolecular conversion to produce electronically excited states of oxyluciferin, the dioxetanone is decarboxylated. Finally, the return of excited oxyluciferin to the ground state 5 results in emission of visible light. For more detailed insights into the reaction mechanism, including alternative reactions and different tautomers of oxyluciferin at varying pH values, readers are referred to additional literature.
2019-07-15
2019-07-15
2019-06-04
Article
0004-9425
10.1071/CH19127
http://hdl.handle.net/10033/621876
Australian Journal of Chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
CSIRO Publishing
oai:repository.helmholtz-hzi.de:10033/6218862019-08-30T11:24:29Zcom_10033_620533col_10033_620534
Discovery pipelines for marine resources: an ocean of opportunity for biotechnology?
Smith, D
Buddie, A G
Goss, R J M
Overmann, J
Lepleux, C
Brönstrup, M
Kloareg, B
Meiners, T
Brennecke, P
Ianora, A
Bouget, F-Y
Gribbon, P
Pina, M
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Discovery pipeline
Marine
Microorganism
microbial domain Biological Resource Centres (mBRC)
Marine microbial diversity offers enormous potential for discovery of compounds of crucial importance in healthcare, food security and bioindustry. However, access to it has been hampered by the difficulty of accessing and growing the organisms for study. The discovery and exploitation of marine bioproducts for research and commercial development requires state-of-the-art technologies and innovative approaches. Technologies and approaches are advancing rapidly and keeping pace is expensive and time consuming. There is a pressing need for clear guidance that will allow researchers to operate in a way that enables the optimal return on their efforts whilst being fully compliant with the current regulatory framework. One major initiative launched to achieve this, has been the advent of European Research Infrastructures. Research Infrastructures (RI) and associated centres of excellence currently build harmonized multidisciplinary workflows that support academic and private sector users. The European Marine Biological Research Infrastructure Cluster (EMBRIC) has brought together six such RIs in a European project to promote the blue bio-economy. The overarching objective is to develop coherent chains of high-quality services for access to biological, analytical and data resources providing improvements in the throughput and efficiency of workflows for discovery of novel marine products. In order to test the efficiency of this prototype pipeline for discovery, 248 rarely-grown organisms were isolated and analysed, some extracts demonstrated interesting biochemical properties and are currently undergoing further analysis. EMBRIC has established an overarching and operational structure to facilitate the integration of the multidisciplinary value chains of services to access such resources whilst enabling critical mass to focus on problem resolution.
2019-07-22
2019-07-22
2019-07-02
Article
World J Microbiol Biotechnol. 2019 Jul 2;35(7):107. doi:10.1007/s11274-019-2685-y.
1573-0972
31267318
10.1007/s11274-019-2685-y
http://hdl.handle.net/10033/621886
World journal of microbiology and biotechnology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Springer
oai:repository.helmholtz-hzi.de:10033/6218932019-08-30T11:24:28Zcom_10033_620533col_10033_620534
The intriguing chemistry and biology of soraphens.
Naini, Arun
Sasse, Florenz
Brönstrup, Mark
Covering: up to the end of 2018Soraphens are a class of polyketide natural products discovered from the myxobacterial strain Sorangium cellulosum. The review is intended to provide an overview on the biosynthesis, chemistry and biological properties of soraphens, that represent a prime example to showcase the value of natural products as tools to decipher cell biology, but also to open novel therapeutic options. The prototype soraphen A is an inhibitor of acetyl coenzyme A carboxylase (ACC1/2), an enzyme that converts acetyl-CoA to malonyl-CoA and thereby controls essential cellular metabolic processes like lipogenesis and fatty acid oxidation. Soraphens illustrate how the inhibition of a single target (ACC1/2) may be explored to treat various pathological conditions: initially developed as a fungicide, efforts in the past decade were directed towards human diseases, including diabetes/obesity, cancer, hepatitis C, HIV, and autoimmune disease - and led to a synthetic molecule, discovered by virtual screening of the allosteric binding site of soraphen in ACC, that is currently in phase 2 clinical trials. We will summarize how structural analogs of soraphen A have been generated through extensive isolation efforts, genetic engineering of the biosynthetic gene cluster, semisynthesis as well as partial and total synthesis.
2019-08-05
2019-08-05
2019-04-05
Article
Nat Prod Rep. 2019 Apr 5. doi: 10.1039/c9np00008a.
1460-4752
30950477
10.1039/c9np00008a
http://hdl.handle.net/10033/621893
Natural Product Reports
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Royal Society of Chemistry
oai:repository.helmholtz-hzi.de:10033/6219102019-08-30T11:26:12Zcom_10033_620533col_10033_620534
What you see is what you get: Activity-based probes in single-cell analysis of enzymatic activities
Lentz, Christian S.
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
activity-based protein profiling
chemical probe
enzyme
flow cytometry
molecular imaging
phenotypic heterogeneity
Molecular imaging methods can provide spatio-temporal information about the distribution of biomolecules or biological processes, such as certain enzymatic activities, in single cells. Within a cell, it is possible to define the subcellular location of a target, its trafficking through the cell, colocalization with other biomolecules of interest and involvement in certain cell biological processes. On the other hand, single-cell imaging promises to distinguish cells that are phenotypically different from each other. The corresponding cellular diversity comprises the presence of functionally distinct cells in a population (‘phenotypic heterogeneity’), as well as dynamic cellular responses to external stimuli (‘phenotypic plasticity’), which is highly relevant, e.g. during cell differentiation, activation (of immune cells), or cell death. This review focuses on applications of a certain class of chemical probes, the so-called activity-based probes (ABPs), for visualization of enzymatic activities in the single-cell context. It discusses the structure of ABPs and other chemical probes, exemplary applications of ABPs in single-cell studies in human, mouse and bacterial systems and considerations to be made with regard to data interpretation
2019-08-20
2019-08-20
2019-01-01
Article
14316730
10.1515/hsz-2019-0262
https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85069763141&origin=inward
http://hdl.handle.net/10033/621910
Chemical Biology
2-s2.0-85069763141
SCOPUS_ID:85069763141
en
Biological Chemistry
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
DeGruyter
oai:repository.helmholtz-hzi.de:10033/6219342019-09-14T01:29:00Zcom_10033_620533col_10033_620534
Isolation and characterisation of irinans, androstane-type withanolides from L.
Stein, Annika
Compera, Dave
Karge, Bianka
Brönstrup, Mark
Franke, Jakob
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Physalis peruviana
androstanes
steroids
structure elucidation
withanolides
Withanolides are steroidal lactones widespread in Nightshade plants with often potent antiproliferative activities. Additionally, the structural diversity of this compound class holds much potential for the discovery of novel biological activity. Here, we report two newly characterised withanolides, named irinans, from Physalis peruviana with highly unusual truncated backbones that resemble mammalian androstane sex hormones. Based on biomimetic chemical reactions, we propose a model that links these compounds to withanolide biosynthesis. Irinans have potent antiproliferative activities, that are however lower than those of 4ß-hydroxywithanolide E. Our work establishes androwithanolides as a new subclass of withanolides.
2019-09-13
2019-09-13
2019-01-01
Article
Beilstein J Org Chem. 2019 Aug 23;15:2003-2012. doi: 10.3762/bjoc.15.196. eCollection 2019.
1860-5397
31501667
10.3762/bjoc.15.196
http://hdl.handle.net/10033/621934
Beilstein Journal of organic Chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Beilstein Institut
oai:repository.helmholtz-hzi.de:10033/6219542019-09-21T01:29:33Zcom_10033_620533col_10033_620534
Hydantoin analogs inhibit the fully assembled ClpXP protease without affecting the individual peptidase and chaperone domains.
Fetzer, Christian
Korotkov, Vadim S
Sieber, Stephan A
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Proteolysis mediated by ClpXP is a crucial cellular process linked to bacterial pathogenesis. The development of specific inhibitors has largely focused on ClpP. However, this focus was challenged by a recent finding showing that conformational control by ClpX leads to a rejection of ClpP binders. Thus, we here follow up on a hit molecule from a high throughput screen performed against the whole ClpXP complex and demonstrate that stable inhibition with high potency is possible. Further investigations revealed that the small molecule binds to ClpP without affecting its activity. Likewise, the molecule does not inhibit ClpX and retains the overall oligomeric state of ClpXP upon binding. Structure activity relationship studies confirmed structural constraints in all three parts of the molecule suggesting binding into a defined stereospecific pocket. Overall, the inhibition of ClpXP without affecting the individual components represents a novel mechanism with perspectives for further optimization for in situ applications.
2019-09-20
2019-09-20
2019-08-14
Article
Org Biomol Chem. 2019 Aug 14;17(30):7124-7127. doi: 10.1039/c9ob01339c. Epub 2019 Jul 17.
1477-0539
31313793
10.1039/c9ob01339c
http://hdl.handle.net/10033/621954
Organic and Biomolecular Chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Royal Society of Chemistry
oai:repository.helmholtz-hzi.de:10033/6219922019-11-08T12:50:04Zcom_10033_620533com_10033_620656col_10033_620534col_10033_620657col_10033_620658
Anti-biofilm Agents against Pseudomonas aeruginosa: A Structure-Activity Relationship Study of C-Glycosidic LecB Inhibitors
Sommer, Roman
Rox, Katharina
Wagner, Stefanie
Hauck, Dirk
Henrikus, Sarah S
Newsad, Shelby
Arnold, Tatjana
Ryckmans, Thomas
Brönstrup, Mark
Imberty, Anne
Varrot, Annabelle
Hartmann, Rolf W
Titz, Alexander
HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany.; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Biofilm formation is a key mechanism of antimicrobial resistance. We have recently reported two classes of orally bioavailable C-glycosidic inhibitors of the Pseudomonas aeruginosa lectin LecB with antibiofilm activity. They proved efficient in target binding, were metabolically stable, nontoxic, selective, and potent in inhibiting formation of bacterial biofilm. Here, we designed and synthesized six new carboxamides and 24 new sulfonamides for a detailed structure-activity relationship for two clinically representative LecB variants. Sulfonamides generally showed higher inhibition compared to carboxamides, which was rationalized based on crystal structure analyses. Substitutions at the thiophenesulfonamide increased binding through extensive contacts with a lipophilic protein patch. These metabolically stable compounds showed a further increase in potency toward the target and in biofilm inhibition assays. In general, we established the structure-activity relationship for these promising antibiofilm agents and showed that modification of the sulfonamide residue bears future optimization potential.
2019-10-28
2019-10-28
2019-10-24
Article
J Med Chem. 2019 Oct 24;62(20):9201-9216. doi: 10.1021/acs.jmedchem.9b01120. Epub 2019 Oct 11.
1520-4804
31553873
10.1021/acs.jmedchem.9b01120
http://hdl.handle.net/10033/621992
Journal of medicinal Chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
American Chemical Society
oai:repository.helmholtz-hzi.de:10033/6220282019-11-26T02:09:24Zcom_10033_620533com_10033_620589com_10033_620618col_10033_620534col_10033_620622col_10033_620608col_10033_620590
Labyrinthopeptins exert broad-spectrum antiviral activity through lipid-binding-mediated virolysis.
Prochnow, Hans
Rox, Katharina
Birudukota, N V Suryanarayana
Weichert, Loreen
Hotop, Sven-Kevin
Klahn, Philipp
Mohr, Kathrin
Franz, Sergej
Banda, Dominic H
Blockus, Sebastian
Schreiber, Janine
Haid, Sibylle
Oeyen, Merel
Martinez, Javier P
Süssmuth, Roderich D
Wink, Joachim
Meyerhans, Andreas
Goffinet, Christine
Messerle, Martin
Schulz, Thomas F
Kröger, Andrea
Schols, Dominique
Pietschmann, Thomas
Brönstrup, Mark
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
To counteract the serious health threat posed by known and novel viral pathogens, drugs that target a variety of viruses through a common mechanism have attracted recent attention due to their potential in treating (re-)emerging infections, for which direct acting antivirals are not available. We found that labyrinthopeptins A1 and A2, the prototype congeners of carbacyclic lanthipeptides, inhibit the proliferation of diverse enveloped viruses, including Dengue virus, Zika virus, West Nile virus, Hepatitis C virus, Chikungunya virus, Karposi's Sarcoma-associated Herpes virus, Cytomegalovirus, and Herpes Simplex virus, in the low μM to nM range. Mechanistic studies on viral particles revealed that labyrinthopeptins induce a virolytic effect through binding to the viral membrane lipid phosphatidylethanolamine (PE). These effects are enhanced by a combined equimolar application of both labyrinthopeptins, and a clear synergism was observed across a concentration range corresponding to IC10-IC90 values of the compounds. Time-resolved experiments with large unilamellar vesicles (LUVs) reveal that membrane lipid raft compositions (PC/PE/Chol/SM (17:10:33:40)) are particularly sensitive to labyrinthopeptins compared to PC/PE (90:10) LUVs, even though the overall PE-amount remains constant. Labyrinthopeptins exhibited low cytotoxicity and had favorable pharmacokinetic properties in mice (t1/2= 10.0 h), which designates them as promising antiviral compounds acting by an unusual viral lipid targeting mechanism.Importance For many viral infections, current treatment options are insufficient. Because the development of each antiviral drug is time-consuming and expensive, the prospect of finding broad-spectrum antivirals that can fight multiple, diverse viruses - well-known as well as (re-)emerging species - has gained attention, especially for the treatment of viral co-infections. While most known broad spectrum agents address processes in the host cell, we found that targeting lipids of the free virus outside the host cell with the natural products labyrinthopeptin A1 and A2 is a viable strategy to inhibit the proliferation of a broad range of viruses from different families, including Chikungunya virus, Dengue virus, Zika virus, Karposi's Sarcoma-associated Herpes virus, or Cytomegalovirus. Labyrinthopeptins bind to viral phosphatidylethanolamine and induce virolysis without exerting cytotoxicity to host cells. This represents a novel and unusual mechanism to tackle medically relevant viral infections.
2019-11-25
2019-11-25
2019-10-30
Article
J Virol. 2019 Oct 30. pii: JVI.01471-19. doi: 10.1128/JVI.01471-19.
1098-5514
31666384
10.1128/JVI.01471-19
http://hdl.handle.net/10033/622028
Journal of Virology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
ASM
oai:repository.helmholtz-hzi.de:10033/6220632020-01-07T02:02:39Zcom_10033_620533col_10033_620534
Evidence for inoculum size and gas interfaces as critical factors in bacterial biofilm formation on magnesium implants in an animal model.
Rahim, Muhammad Imran
Szafrański, Szymon P
Ingendoh-Tsakmakidis, Alexandra
Stiesch, Meike
Mueller, Peter P
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Animal model
Antibiotic resistance
Bacterial biofilm
Bioluminescence
Gas interfaces
Magnesium alloy implant
Pseudomonas aeruginosa
in vivo imaging
Infections of medical implants caused by bacterial biofilms are a major clinical problem. Bacterial colonization is predicted to be prevented by alkaline magnesium surfaces. However, in experimental animal studies, magnesium implants prolonged infections. The reason for this peculiarity likely lies within the ‒still largely hypothetical‒ mechanism by which infection arises. Investigating subcutaneous magnesium implants infected with bioluminescent Pseudomonas aeruginosa via in vivo imaging, we found that the rate of implant infections was critically dependent on a surprisingly high quantity of injected bacteria. At high inocula, bacteria were antibiotic-refractory immediately after infection. High cell densities are known to limit nutrient availability, restricting proliferation and trigger quorum sensing which could both contribute to the rapid initial resistance. We propose that gas bubbles such as those formed during magnesium corrosion, can then act as interfaces that support biofilm formation and permit long-term survival. This model could provide an explanation for the apparent ineffectiveness of innovative contact-dependent bactericidal implant surfaces in patients. In addition, the model points toward air bubbles in tissue, either by inclusion during surgery or by spontaneous gas bubble formation later on, could constitute a key risk factor for clinical implant infections
2020-01-06
2020-01-06
2019-11-28
Article
olloids Surf B Biointerfaces. 2019 Nov 28;186:110684. doi: 10.1016/j.colsurfb.2019.110684.
1873-4367
31812076
10.1016/j.colsurfb.2019.110684
http://hdl.handle.net/10033/622063
Colloids and Surfaces B, Biointerfaces
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Elsevier
oai:repository.helmholtz-hzi.de:10033/6220652020-01-09T03:06:29Zcom_10033_620533com_10033_620857com_10033_311308com_10033_620618col_10033_620534col_10033_620858col_10033_620721col_10033_620622
The nuclear export inhibitor aminoratjadone is a potent effector in extracellular-targeted drug conjugates.
Klahn, Philipp
Fetz, Verena
Ritter, Antje
Collisi, Wera
Hinkelmann, Bettina
Arnold, Tatjana
Tegge, Werner
Rox, Katharina
Hüttel, Stephan
Mohr, Kathrin I
Wink, Joachim
Stadler, Marc
Wissing, Josef
Jänsch, Lothar
Brönstrup, Mark
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
The concept of targeted drug conjugates has been successfully translated to clinical practice in oncology. Whereas the majority of cytotoxic effectors in drug conjugates are directed against either DNA or tubulin, our study aimed to validate nuclear export inhibition as a novel effector principle in drug conjugates. For this purpose, a semisynthetic route starting from the natural product ratjadone A, a potent nuclear export inhibitor, has been developed. The biological evaluation of ratjadones functionalized at the 16-position revealed that oxo- and amino-analogues had very high potencies against cancer cell lines (e.g. 16R-aminoratjadone 16 with IC50 = 260 pM against MCF-7 cells, or 19-oxoratjadone 14 with IC50 = 100 pM against A-549 cells). Mechanistically, the conjugates retained a nuclear export inhibitory activity through binding CRM1. To demonstrate a proof-of-principle for cellular targeting, folate- and luteinizing hormone releasing hormone (LHRH)-based carrier molecules were synthesized and coupled to aminoratjadones as well as fluorescein for cellular efficacy and imaging studies, respectively. The Trojan-Horse conjugates selectively addressed receptor-positive cell lines and were highly potent inhibitors of their proliferation. For example, the folate conjugate FA-7-Val-Cit-pABA-16R-aminoratjadone had an IC50 of 34.3 nM, and the LHRH conjugate d-Orn-Gose-Val-Cit-pABA-16R-aminoratjadone had an IC50 of 12.8 nM. The results demonstrate that nuclear export inhibition is a promising mode-of-action for extracellular-targeted drug conjugate payloads.
2020-01-08
2020-01-08
2019-05-28
Article
Chem Sci. 2019 Apr 15;10(20):5197-5210. doi: 10.1039/c8sc05542d. eCollection 2019 May 28.
2041-6520
31191875
10.1039/c8sc05542d
http://hdl.handle.net/10033/622065
Chemical Science
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Royal Society of Chemistry
oai:repository.helmholtz-hzi.de:10033/6220922020-01-21T02:01:29Zcom_10033_620533com_10033_620618col_10033_620534col_10033_620619
Semisynthesis and biological evaluation of amidochelocardin derivatives as broad-spectrum antibiotics.
Grandclaudon, Charlotte
Birudukota, N V Suryanarayana
Elgaher, Walid A M
Jumde, Ravindra P
Yahiaoui, Samir
Arisetti, Nanaji
Hennessen, Fabienne
Hüttel, Stephan
Stadler, Marc
Herrmann, Jennifer
Miethke, Marcus
Hartmann, Rolf W
Müller, Rolf
Hirsch, Anna K H
Brönstrup, Mark
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Antibiotics
Chelocardin
Gram-negative bacteria
Natural product
Semisynthesis
Tetracycline
To address the global challenge of emerging antimicrobial resistance, the hitherto most successful strategy to new antibiotics has been the optimization of validated natural products; most of these efforts rely on semisynthesis. Herein, we report the semisynthetic modification of amidochelocardin, an atypical tetracycline obtained via genetic engineering of the chelocardin producer strain. We report modifications at C4, C7, C10 and C11 by the application of methylation, acylation, electrophilic substitution, and oxidative C-C coupling reactions. The antibacterial activity of the reaction products was tested against a panel of Gram-positive and Gram-negative pathogens. The emerging structure-activity relationships (SARs) revealed that positions C7 and C10 are favorable anchor points for the semisynthesis of optimized derivatives. The observed SAR was different from that known for tetracyclines, which underlines the pronounced differences between the two compound classes.
2020-01-20
2020-01-20
2019-12-20
Article
Eur J Med Chem. 2019 Dec 20;188:112005. doi: 10.1016/j.ejmech.2019.112005.
1768-3254
31911294
10.1016/j.ejmech.2019.112005
http://hdl.handle.net/10033/622092
European journal of medicinal chemistry
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Elsevier
oai:repository.helmholtz-hzi.de:10033/6221022020-01-22T02:27:21Zcom_10033_620533col_10033_620534
T4SS-dependent TLR5 activation by Helicobacter pylori infection.
Pachathundikandi, Suneesh Kumar
Tegtmeyer, Nicole
Arnold, Isabelle Catherine
Lind, Judith
Neddermann, Matthias
Falkeis-Veits, Christina
Chattopadhyay, Sujay
Brönstrup, Mark
Tegge, Werner
Hong, Minsun
Sticht, Heinrich
Vieth, Michael
Müller, Anne
Backert, Steffen
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Toll-like receptor TLR5 recognizes a conserved domain, termed D1, that is present in flagellins of several pathogenic bacteria but not in Helicobacter pylori. Highly virulent H. pylori strains possess a type IV secretion system (T4SS) for delivery of virulence factors into gastric epithelial cells. Here, we show that one of the H. pylori T4SS components, protein CagL, can act as a flagellin-independent TLR5 activator. CagL contains a D1-like motif that mediates adherence to TLR5+ epithelial cells, TLR5 activation, and downstream signaling in vitro. TLR5 expression is associated with H. pylori infection and gastric lesions in human biopsies. Using Tlr5-knockout and wild-type mice, we show that TLR5 is important for efficient control of H. pylori infection. Our results indicate that CagL, by activating TLR5, may modulate immune responses to H. pylori.
2020-01-21
2020-01-21
2019-12-16
Article
Nat Commun. 2019 Dec 16;10(1):5717. doi: 10.1038/s41467-019-13506-6.
2041-1723
31844047
10.1038/s41467-019-13506-6
http://hdl.handle.net/10033/622102
Nature communication
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Nature publishing group
oai:repository.helmholtz-hzi.de:10033/6221282020-02-12T12:12:58Zcom_10033_620533com_10033_620618com_10033_620656col_10033_620534col_10033_620657col_10033_620619
Cystobactamid 507: Concise Synthesis, Mode of Action and Optimization toward More Potent Antibiotics.
Elgaher, Walid A M
Hamed, Mostafa M
Baumann, Sascha
Herrmann, Jennifer
Siebenbürger, Lorenz
Krull, Jana
Cirnski, Katarina
Kirschning, Andreas
Brönstrup, Mark
Müller, Rolf
Hartmann, Rolf W
HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany.
Bioactive conformation * Cystobactamids * Drug design * Intramolecular hydrogen bond * Total synthesis
Lack of new antibiotics and increasing antimicrobial resistance are the main concerns of healthcare community nowadays, which necessitate the search for novel antibacterial agents. Recently, we discovered the cystobactamids - a novel natural class of antibiotics with broad-spectrum antibacterial activity. In this work, we describe a concise total synthesis of cystobactamid 507, the identification of the bioactive conformation using non-covalently bonded rigid analogs, the first structure–activity relationship (SAR) study for cystobactamid 507 leading to new analogs with high metabolic stability, superior topoisomerase IIA inhibition, antibacterial activity and, importantly, stability toward the resistant factor AlbD. Deeper insight into the mode of action revealed that the cystobactamids employ DNA minor groove binding as part of the drug–target interaction without showing significant intercalation. By designing a new analog of cystobactamid 919-2 we finally demonstrated that these findings could be further exploited to obtain more potent hexapeptides against Gram-negative bacteria.
2020-02-12
2020-02-12
2020-01-26
Article
Chemistry. 2020 Jan 26. doi: 10.1002/chem.202000117.
1521-3765
31984562
10.1002/chem.202000117
http://hdl.handle.net/10033/622128
Chemistry A European journal
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Wiley-VCH
oai:repository.helmholtz-hzi.de:10033/6221322020-02-14T04:06:08Zcom_10033_620533com_10033_620618com_10033_620656col_10033_620534col_10033_620657col_10033_620619
Discovery of Novel Latency-Associated Nuclear Antigen Inhibitors as Antiviral Agents Against Kaposi's Sarcoma-Associated Herpesvirus.
Kirsch, Philine
Jakob, Valentin
Elgaher, Walid A M
Walt, Christine
Oberhausen, Kevin
Schulz, Thomas F
Empting, Martin
HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany.;HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
With the aim to develop novel antiviral agents against Kaposi's Sarcoma Herpesvirus (KSHV), we are targeting the latency-associated nuclear antigen (LANA). This protein plays an important role in viral genome maintenance during latent infection. LANA has the ability to tether the viral genome to the host nucleosomes and, thus, ensures latent persistence of the viral genome in the host cells. By inhibition of the LANA-DNA interaction, we seek to eliminate or reduce the load of the viral DNA in the host. To achieve this goal, we screened our in-house library using a dedicated fluorescence polarization (FP)-based competition assay, which allows for the quantification of LANA-DNA-interaction inhibition by small organic molecules. We successfully identified three different compound classes capable of disrupting this protein-nucleic acid interaction. We characterized these compounds by IC50 dose-response evaluation and confirmed the compound-LANA interaction using surface plasmon resonance (SPR) spectroscopy. Furthermore, two of the three hit scaffolds showed only marginal cytotoxicity in two human cell lines. Finally, we conducted STD-NMR competition experiments with our new hit compounds and a previously described fragment-sized inhibitor. Based on these results, future compound linking approaches could serve as a promising strategy for further optimization studies in order to generate highly potent KSHV inhibitors.
2020-02-13
2020-02-13
2020-01-24
Article
ACS Chem Biol. 2020 Jan 24. doi: 10.1021/acschembio.9b00845.
1554-8937
31944659
10.1021/acschembio.9b00845
http://hdl.handle.net/10033/622132
ACS Chemical Biology
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
American Chemical Society (ACS)
oai:repository.helmholtz-hzi.de:10033/6222732020-05-26T01:29:33Zcom_10033_620533com_10033_620857com_10033_620626com_10033_620589col_10033_620534col_10033_620858col_10033_620629col_10033_620590
Labyrinthopeptins as virolytic inhibitors of respiratory syncytial virus cell entry.
Blockus, Sebastian
Sake, Svenja M
Wetzke, Martin
Grethe, Christina
Graalmann, Theresa
Pils, Marina
Le Goffic, Ronan
Galloux, Marie
Prochnow, Hans
Rox, Katharina
Hüttel, Stephan
Rupcic, Zeljka
Wiegmann, Bettina
Dijkman, Ronald
Rameix-Welti, Marie-Anne
Eléouët, Jean-François
Duprex, W Paul
Thiel, Volker
Hansen, Gesine
Brönstrup, Mark
Haid, Sibylle
Pietschmann, Thomas
TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany.
Antiviral activity
Human respiratory syncytial virus (hRSV)
Labyrinthopeptin
Lanthipeptide
Virolytic
Virus entry
Acute lower respiratory tract infections (ALRI) caused by respiratory syncytial virus (RSV) are associated with a severe disease burden among infants and elderly patients. Treatment options are limited. While numerous drug candidates with different viral targets are under development, the utility of RSV entry inhibitors is challenged by a low resistance barrier and by single mutations causing cross-resistance against a wide spectrum of fusion inhibitor chemotypes. We developed a cell-based screening assay for discovery of compounds inhibiting infection with primary RSV isolates. Using this system, we identified labyrinthopeptin A1 and A2 (Laby A1/A2), lantibiotics isolated from Actinomadura namibiensis, as effective RSV cell entry inhibitors with IC50s of 0.39 μM and 4.97 μM, respectively, and with favourable therapeutic index (>200 and > 20, respectively). Both molecules were active against multiple RSV strains including primary isolates and their antiviral activity against RSV was confirmed in primary human airway cells ex vivo and a murine model in vivo. Laby A1/A2 were antiviral in prophylactic and therapeutic treatment regimens and displayed synergistic activity when applied in combination with each other. Mechanistic studies showed that Laby A1/A2 exert virolytic activity likely by binding to phosphatidylethanolamine moieties within the viral membrane and by disrupting virus particle membrane integrity. Probably due to its specific mode of action, Laby A1/A2 antiviral activity was not affected by common resistance mutations to known RSV entry inhibitors. Taken together, Laby A1/A2 represent promising candidates for development as RSV inhibitors. Moreover, the cell-based screening system with primary RSV isolates described here should be useful to identify further antiviral agents.
2020-05-25
2020-05-25
2020-03-18
Article
Antiviral Res. 2020;177:104774. doi:10.1016/j.antiviral.2020.104774.
32197980
10.1016/j.antiviral.2020.104774
http://hdl.handle.net/10033/622273
1872-9096
Antiviral research
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Elsevier
oai:repository.helmholtz-hzi.de:10033/6222762020-05-28T01:51:33Zcom_10033_620533col_10033_620534
Crystal structure of SARS-CoV-2 main protease provides a basis for design of improved α-ketoamide inhibitors.
Zhang, Linlin
Lin, Daizong
Sun, Xinyuanyuan
Curth, Ute
Drosten, Christian
Sauerhering, Lucie
Becker, Stephan
Rox, Katharina
Hilgenfeld, Rolf
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is a global health emergency. An attractive drug target among coronaviruses is the main protease (Mpro, also called 3CLpro) because of its essential role in processing the polyproteins that are translated from the viral RNA. We report the x-ray structures of the unliganded SARS-CoV-2 Mpro and its complex with an α-ketoamide inhibitor. This was derived from a previously designed inhibitor but with the P3-P2 amide bond incorporated into a pyridone ring to enhance the half-life of the compound in plasma. On the basis of the unliganded structure, we developed the lead compound into a potent inhibitor of the SARS-CoV-2 Mpro The pharmacokinetic characterization of the optimized inhibitor reveals a pronounced lung tropism and suitability for administration by the inhalative route.
2020-05-27
2020-05-27
2020-03-20
Article
Other
Science. 2020;368(6489):409‐412. doi:10.1126/science.abb3405
32198291
10.1126/science.abb3405
http://hdl.handle.net/10033/622276
1095-9203
Science (New York, N.Y.)
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
AAAS
oai:repository.helmholtz-hzi.de:10033/6222812020-06-04T02:29:11Zcom_10033_620533com_10033_620618com_10033_620656col_10033_620534col_10033_620657col_10033_620619
Cystobactamid 507: Concise Synthesis, Mode of Action, and Optimization toward More Potent Antibiotics.
Elgaher, Walid A M
Hamed, Mostafa M
Baumann, Sascha
Herrmann, Jennifer
Siebenbürger, Lorenz
Krull, Jana
Cirnski, Katarina
Kirschning, Andreas
Brönstrup, Mark
Müller, Rolf
Hartmann, Rolf W
HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany.
antibiotics
conformation analysis
drug design
hydrogen bonds
total synthesis
Lack of new antibiotics and increasing antimicrobial resistance are among the main concerns of healthcare communities nowadays, and these concerns necessitate the search for novel antibacterial agents. Recently, we discovered the cystobactamids-a novel natural class of antibiotics with broad-spectrum antibacterial activity. In this work, we describe 1) a concise total synthesis of cystobactamid 507, 2) the identification of the bioactive conformation using noncovalently bonded rigid analogues, and 3) the first structure-activity relationship (SAR) study for cystobactamid 507 leading to new analogues with high metabolic stability, superior topoisomerase IIA inhibition, antibacterial activity and, importantly, stability toward the resistant factor AlbD. Deeper insight into the mode of action revealed that the cystobactamids employ DNA minor-groove binding as part of the drug-target interaction without showing significant intercalation. By designing a new analogue of cystobactamid 919-2, we finally demonstrated that these findings could be further exploited to obtain more potent hexapeptides against Gram-negative bacteria.
2020-06-03
2020-06-03
2020-01-26
Article
Chemistry. 2020;10.1002/chem.202000117. doi:10.1002/chem.202000117.
31984562
10.1002/chem.202000117
http://hdl.handle.net/10033/622281
1521-3765
Chemistry (Weinheim an der Bergstrasse, Germany)
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Wiley
oai:repository.helmholtz-hzi.de:10033/6223002020-06-17T01:30:52Zcom_10033_620533com_10033_311624com_10033_6839com_10033_620652com_10033_620618col_10033_620672col_10033_620534col_10033_311625col_10033_620622
Expansion of functional personalized cells with specific transgene combinations.
Lipps, Christoph
Klein, Franziska
Wahlicht, Tom
Seiffert, Virginia
Butueva, Milada
Zauers, Jeannette
Truschel, Theresa
Luckner, Martin
Köster, Mario
MacLeod, Roderick
Pezoldt, Jörn
Hühn, Jochen
Yuan, Qinggong
Müller, Peter Paul
Kempf, Henning
Zweigerdt, Robert
Dittrich-Breiholz, Oliver
Pufe, Thomas
Beckmann, Rainer
Drescher, Wolf
Riancho, Jose
Sañudo, Carolina
Korff, Thomas
Opalka, Bertram
Rebmann, Vera
Göthert, Joachim R
Alves, Paula M
Ott, Michael
Schucht, Roland
Hauser, Hansjörg
Wirth, Dagmar
May, Tobias
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
Fundamental research and drug development for personalized medicine necessitates cell cultures from defined genetic backgrounds. However, providing sufficient numbers of authentic cells from individuals poses a challenge. Here, we present a new strategy for rapid cell expansion that overcomes current limitations. Using a small gene library, we expanded primary cells from different tissues, donors, and species. Cell-type-specific regimens that allow the reproducible creation of cell lines were identified. In depth characterization of a series of endothelial and hepatocytic cell lines confirmed phenotypic stability and functionality. Applying this technology enables rapid, efficient, and reliable production of unlimited numbers of personalized cells. As such, these cell systems support mechanistic studies, epidemiological research, and tailored drug development.
2020-06-16
2020-06-16
2018-03-08
Article
Other
Nat Commun. 2018;9(1):994. Published 2018 Mar 8. doi:10.1038/s41467-018-03408-4.
29520052
10.1038/s41467-018-03408-4
http://hdl.handle.net/10033/622300
2041-1723
Nature communications
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
Springer Nature
oai:repository.helmholtz-hzi.de:10033/6223172020-07-01T02:33:47Zcom_10033_620533com_10033_620589col_10033_620534col_10033_620590
Filovirus antiviral activity of cationic amphiphilic drugs is associated with lipophilicity and ability to induce phospholipidosis.
Gunesch, Antonia P
Zapatero-Belinchon, Francisco J
Pinkert, Lukas
Steinmann, Eike
Manns, Michael P
Schneider, Gisbert
Pietschmann, Thomas
Brönstrup, Mark
von Hahn, Thomas
HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany.
Several cationic amphiphilic drugs (CADs) have been found to inhibit cell entry of filoviruses and other enveloped viruses. Structurally unrelated CADs may have antiviral activity, yet the underlying common mechanism and structure-activity relationship are incompletely understood.We aimed to understand how widespread antiviral activity is among CADs and which structural and physico-chemical properties are linked to entry inhibition.We measured inhibition of Marburg virus pseudoparticle (MARVpp) cell entry by 45 heterogeneous and mostly FDA-approved CADs and cytotoxicity in EA.hy926 cells. We analysed correlation of antiviral activity with four chemical properties: pKa, ClogP, molecular weight and distance between the basic group and hydrophobic ring structures. Additionally, we quantified drug-induced phospholipidosis (DIPL) of a CAD subset by flow cytometry. Structurally similar compounds (derivatives) and those with similar chemical properties but unrelated structure (analogues) to strong inhibitors were obtained by two in silico similarity search approaches and tested for antiviral activity. Overall 11 out of 45 (24 %) CADs inhibited MARVpp by 40 % or more. The strongest antiviral compounds were dronedarone, triparanol and quinacrine. Structure-activity relationship studies revealed highly significant correlations between antiviral activity, hydrophobicity (ClogP>4), and DIPL. Moreover, pKa and intra-molecular distance between hydrophobic and hydrophilic moieties correlated with antiviral activity, but to a lesser extent. We also showed that in contrast to analogues, derivatives had similar antiviral activity as the seed compound dronedarone. Overall, one quarter of CADs inhibits MARVpp entry in vitro and antiviral activity of CADs mostly relies on their hydrophobicity, yet is promoted by the individual structure.
2020-06-29
2020-06-29
2020-06-08
Article
Antimicrob Agents Chemother. 2020;AAC.00143-20. doi:10.1128/AAC.00143-20.
32513799
http://hdl.handle.net/10033/622317
1098-6596
Antimicrobial agents and chemotherapy
en
http://creativecommons.org/licenses/by-nc-sa/4.0/
Attribution-NonCommercial-ShareAlike 4.0 International
ASM
etdms///col_10033_620534/100