Recent Submissions

  • Concepts and Methods to Access Novel Antibiotics from Actinomycetes.

    Hug, Joachim J; Bader, Chantal D; Remškar, Maja; Cirnski, Katarina; Müller, Rolf (MPDI, 2018-05-22)
    Actinomycetes have been proven to be an excellent source of secondary metabolites for more than half a century. Exhibiting various bioactivities, they provide valuable approved drugs in clinical use. Most microorganisms are still untapped in terms of their capacity to produce secondary metabolites, since only a small fraction can be cultured in the laboratory. Thus, improving cultivation techniques to extend the range of secondary metabolite producers accessible under laboratory conditions is an important first step in prospecting underexplored sources for the isolation of novel antibiotics. Currently uncultured actinobacteria can be made available by bioprospecting extreme or simply habitats other than soil. Furthermore, bioinformatic analysis of genomes reveals most producers to harbour many more biosynthetic gene clusters than compounds identified from any single strain, which translates into a silent biosynthetic potential of the microbial world for the production of yet unknown natural products. This review covers discovery strategies and innovative methods recently employed to access the untapped reservoir of natural products. The focus is the order of actinomycetes although most approaches are similarly applicable to other microbes. Advanced cultivation methods, genomics- and metagenomics-based approaches, as well as modern metabolomics-inspired methods are highlighted to emphasise the interplay of different disciplines to improve access to novel natural products.
  • Post-translational Serine/Threonine Phosphorylation and Lysine Acetylation: A Novel Regulatory Aspect of the Global Nitrogen Response Regulator GlnR in S. coelicolor M145.

    Amin, Rafat; Franz-Wachtel, Mirita; Tiffert, Yvonne; Heberer, Martin; Meky, Mohamed; Ahmed, Yousra; Matthews, Arne; Krysenko, Sergii; Jakobi, Marco; Hinder, Markus; Moore, Jane; Okoniewski, Nicole; Maček, Boris; Wohlleben, Wolfgang; Bera, Agnieszka; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (Frontiers, 2016-01-01)
    Soil-dwelling Streptomyces bacteria such as S.coelicolor have to constantly adapt to the nitrogen (N) availability in their habitat. Thus, strict transcriptional and post-translational control of the N-assimilation is fundamental for survival of this species. GlnR is a global response regulator that controls transcription of the genes related to the N-assimilation in S. coelicolor and other members of the Actinomycetales. GlnR represents an atypical orphan response regulator that is not activated by the phosphorylation of the conserved aspartate residue (Asp 50). We have applied transcriptional analysis, LC-MS/MS analysis and electrophoretic mobility shift assays (EMSAs) to understand the regulation of GlnR in S. coelicolor M145. The expression of glnR and GlnR-target genes was revisited under four different N-defined conditions and a complex N-rich condition. Although, the expression of selected GlnR-target genes was strongly responsive to changing N-concentrations, the glnR expression itself was independent of the N-availability. Using LC-MS/MSanalysis we demonstrated that GlnR was post-translationally modified. The post-translational modifications of GlnR comprise phosphorylation of the serine/threonine residues and acetylation of lysine residues. In the complex N-rich medium GlnR was phosphorylated on six serine/threonine residues and acetylated on one lysine residue. Under defined N-excess conditions only two phosphorylated residues were detected whereas under defined N-limiting conditions no phosphorylation was observed. GlnR phosphorylation is thus clearly correlated with N-rich conditions. Furthermore, GlnR was acetylated on four lysine residues independently of the N-concentration in the defined media and on only one lysine residue in the complex N-rich medium. Using EMSAs we demonstrated that phosphorylation inhibited the binding of GlnR to its targets genes, whereas acetylation had little influence on the formation of GlnR-DNA complex. This study clearly demonstrated that GlnR DNA-binding affinity is modulated by post-translational modifications in response to changing N-conditions in order to elicit a proper transcriptional response to the latter.
  • Heterologous Expression of the Nybomycin Gene Cluster from the Marine StrainStreptomyces albus subsp. NRRL B-24108.

    Rodríguez Estévez, Marta; Myronovskyi, Maksym; Gummerlich, Nils; Nadmid, Suvd; Luzhetskyy, Andriy; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (MDPI, 2018-11-04)
    Streptomycetes represent an important reservoir of active secondary metabolites with potential applications in the pharmaceutical industry. The gene clusters responsible for their production are often cryptic under laboratory growth conditions. Characterization of these clusters is therefore essential for the discovery of new microbial pharmaceutical drugs. Here, we report the identification of the previously uncharacterized nybomycin gene cluster from the marine actinomycete
  • Metabolic and Biosynthetic Diversity in Marine Myxobacteria.

    Gemperlein, Katja; Zaburannyi, Nestor; Garcia, Ronald; La Clair, James J; Müller, Rolf; HIPS, Helmholtz-Institut für Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (2018-09-05)
    Prior to 2005, the vast majority of characterized myxobacteria were obtained from terrestrial habitats. Since then, several species of halotolerant and even obligate marine myxobacteria have been described. Chemical analyses of extracts from these organisms have confirmed their ability to produce secondary metabolites with unique chemical scaffolds. Indeed, new genera of marine-derived myxobacteria, particularly Enhygromyxa, have been shown to produce novel chemical scaffolds that differ from those observed in soil myxobacteria. Further studies have shown that marine sponges and terrestrial myxobacteria are capable of producing similar or even identical secondary metabolites, suggesting that myxobacterial symbionts may have been the true producers. Recent in silico analysis of the genome sequences available from six marine myxobacteria disclosed a remarkably versatile biosynthetic potential. With access to ever-advancing tools for small molecule and genetic evaluation, these studies suggest a bright future for expeditions into this yet untapped resource for secondary metabolites
  • Mast cells as protectors of health.

    Dudeck, Anne; Köberle, Martin; Goldmann, Oliver; Meyer, Nicole; Dudeck, Jan; Lemmens, Stefanie; Rohde, Manfred; Roldán, Nestor González; Dietze-Schwonberg, Kirsten; Orinska, Zane; Medina, Eva; Hendrix, Sven; Metz, Martin; Zenclussen, Ana Claudia; von Stebut, Esther; Biedermann, Tilo; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.; HIPS, Helmholtz-Institut füt Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (Elsevier, 2018-11-20)
    Mast cells (MC), well known for their effector functions in Th2 skewed allergic and also autoimmune inflammation, become increasingly acknowledged for their role in protection of health. It is now clear that they are also key modulators of immune responses at interface organs like skin or gut. MC can prime tissues for adequate inflammatory responses and cooperate with dendritic cells in T cell activation. They also regulate harmful immune responses in trauma and help to successfully orchestrate pregnancy. This review focusses on the beneficial effects of mast cells on tissue homeostasis and elimination of toxins or venoms. MC can enhance pathogen clearance in many bacterial, viral, and parasite infections, e.g. by TLR2 triggered degranulation, secretion of antimicrobial cathelicidins, recruiting neutrophils or by providing extracellular DNA traps. The role of MC in tumors is more ambiguous, however, encouraging new findings show they can change the tumor microenvironment towards anti-tumor immunity when adequately triggered. Uterine tissue remodeling by α-chymase (MCP-5) is crucial for successful embryo implantation. MCP-4 and the tryptase MCP-6 emerge to be protective in CNS trauma by reducing inflammatory damage and excessive scar formation, thereby protecting axon growth. Last but not least, we see proteases like carboxypeptidase A released by FcεRI activated MC detoxify an increasing number of venoms and endogenous toxins. A better understanding of the plasticity of MC will help to improve these advantageous effects, and hint on ways to cut down detrimental MC actions.
  • An Interferon Signature Discriminates Pneumococcal From Staphylococcal Pneumonia.

    Strehlitz, Anja; Goldmann, Oliver; Pils, Marina C; Pessler, Frank; Medina, Eva; 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. (Frontiers, 2018-01-01)
    Streptococcus pneumoniae is the most common cause of community-acquired pneumonia (CAP). Despite the low prevalence of CAP caused by methicillin-resistant Staphylococcus aureus (MRSA), CAP patients often receive empirical antibiotic therapy providing coverage for MRSA such as vancomycin or linezolid. An early differentiation between S. pneumoniae and S. aureus pneumonia can help to reduce the use of unnecessary antibiotics. The objective of this study was to identify candidate biomarkers that can discriminate pneumococcal from staphylococcal pneumonia. A genome-wide transcriptional analysis of lung and peripheral blood performed in murine models of S. pneumoniae and S. aureus lung infection identified an interferon signature specifically associated with S. pneumoniae infection. Prediction models built using a support vector machine and Monte Carlo cross-validation, identified the combination of the interferon-induced chemokines CXCL9 and CXCL10 serum concentrations as the set of biomarkers with best sensitivity, specificity, and predictive power that enabled an accurate discrimination between S. pneumoniae and S. aureus pneumonia. The predictive performance of these biomarkers was further validated in an independent cohort of mice. This study highlights the potential of serum CXCL9 and CXCL10 biomarkers as an adjunctive diagnostic tool that could facilitate prompt and correct pathogen-targeted therapy in CAP patients.
  • Ala-geninthiocin, a new broad spectrum thiopeptide antibiotic, produced by a marine Streptomyces sp. ICN19.

    Iniyan, Appadurai Muthamil; Sudarman, Enge; Wink, Joachim; Kannan, Rajaretinam Rajesh; Vincent, Samuel Gnana Prakash; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (2018-10-24)
    Bioassay-guided screening of antibacterial compounds from the cultured marine Streptomyces sp. ICN19 provided Ala-geninthiocin (1), along with its known analogs geninthiocin (2) and Val-geninthiocin (3) and the indolocarbazole staurosporine (4). The structure of 1 was determined on the basis of 1D and 2D NMR spectra and ESI-HRMS. The absolute configurations of the amino acid residues were determined by enantioselective GC-MS analysis. Compound 1 exhibited potent activity against Gram-positive bacteria including Staphylococcus aureus, Bacillus subtilis, Mycobacterium smegmatis, and Micrococcus luteus, as well as cytotoxicity against A549 human lung carcinoma cells with an IC50 value of 6 nM
  • Fluorescent Inorganic-Organic Hybrid Nanoparticles

    Neumeier, B. Lilli; Khorenko, Mikhail; Alves, Frauke; Goldmann, Oliver; Napp, Joanna; Schepers, Ute; Reichardt, Holger M.; Feldmann, Claus; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany.
    Inorganic‐organic hybrid nanoparticles (IOH‐NPs) with a general composition [ZrO]2+[RDyeOPO3]2−, [Ln]3+n/3[RDye(SO3)n]n−, [Ln(OH)]2+n/2[RDye(SO3)n]n−, or [LnO]+n[RDye(SO3)n]n− (Ln: lanthanide) are a novel class of nanomaterials for fluorescence detection and optical imaging. IOH‐NPs are characterized by an extremely high load of the fluorescent dye (70–85 wt‐%), high photochemical stability, straightforward aqueous synthesis, low material complexity, intense emission and high cell uptake at low toxicity. Besides full‐color emission, IOH‐NPs are suitable for multimodal imaging, singlet‐oxygen generation as well as drug delivery and drug release. This focus review presents the material concept of the IOH‐NPs as well as their synthesis and characterization. Their characteristic features are illustrated by selected in vitro and in vivo studies to initiate application in biology and medicine.
  • The vacuolar-type ATPase inhibitor archazolid increases tumor cell adhesion to endothelial cells by accumulating extracellular collagen.

    Luong, Betty; Schwenk, Rebecca; Bräutigam, Jacqueline; Müller, Rolf; Menche, Dirk; Bischoff, Iris; Fürst, Robert; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (2018-01-01)
    The vacuolar-type H+-ATPase (v-ATPase) is the major proton pump that acidifies intracellular compartments of eukaryotic cells. Since the inhibition of v-ATPase resulted in anti-tumor and anti-metastatic effects in different tumor models, this enzyme has emerged as promising strategy against cancer. Here, we used the well-established v-ATPase inhibitor archazolid, a natural product first isolated from the myxobacterium Archangium gephyra, to study the consequences of v-ATPase inhibition in endothelial cells (ECs), in particular on the interaction between ECs and cancer cells, which has been neglected so far. Human endothelial cells treated with archazolid showed an increased adhesion of tumor cells, whereas the transendothelial migration of tumor cells was reduced. The adhesion process was independent from the EC adhesion molecules ICAM-1, VCAM-1, E-selectin and N-cadherin. Instead, the adhesion was mediated by β1-integrins expressed on tumor cells, as blocking of the integrin β1 subunit reversed this process. Tumor cells preferentially adhered to the β1-integrin ligand collagen and archazolid led to an increase in the amount of collagen on the surface of ECs. The accumulation of collagen was accompanied by a strong decrease of the expression and activity of the protease cathepsin B. Overexpression of cathepsin B in ECs prevented the capability of archazolid to increase the adhesion of tumor cells onto ECs. Our study demonstrates that the inhibition of v-ATPase by archazolid induces a pro-adhesive phenotype in endothelial cells that promotes their interaction with cancer cells, whereas the transmigration of tumor cells was reduced. These findings further support archazolid as a promising anti-metastatic compound.
  • A "Motif-Oriented" Total Synthesis of Nannocystin Ax. Preparation and Biological Assessment of Analogues.

    Meng, Zhanchao; Souillart, Laetitia; Monks, Brendan; Huwyler, Nikolas; Herrmann, Jennifer; Müller, Rolf; Fürstner, Alois; HIPS, Helmholtz-Institut füt Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (2018-07-06)
    The highly cytotoxic cyclodepsipeptides of the nannocystin family are known to bind to the eukaryotic translation elongation factor 1α (EF-1α). Analysis of the docking pose, as proposed by a previous in silico study, suggested that the trisubstituted alkene moiety and the neighboring methyl ether form a domain that might be closely correlated with biological activity. This hypothesis sponsored a synthetic campaign which was designed to be "motif-oriented": specifically, a sequence of ring closing alkyne metathesis (RCAM) followed by hydroxy-directed trans-hydrostannation of the resulting cycloalkyne was conceived, which allowed this potentially anchoring substructure to be systematically addressed at a late stage. This inherently flexible approach opened access to nannocystin Ax (1) itself as well as to 10 non-natural analogues. While the biological data confirmed the remarkable potency of this class of compounds and showed that the domain in question is indeed an innate part of the pharmacophore, the specific structure/activity relationships can only partly be reconciled with the original in silico docking study; therefore, we conclude that this model needs to be carefully revisited.
  • Synthetic biology approaches and combinatorial biosynthesis towards heterologous lipopeptide production.

    Yan, Fu; Burgard, Christian; Popoff, Alexander; Zaburannyi, Nestor; Zipf, Gregor; Maier, Josef; Bernauer, Hubert S; Wenzel, Silke C; Müller, Rolf; HIPS, Helmholtz-Institut füt Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (2018-10-14)
    Synthetic biology techniques coupled with heterologous secondary metabolite production offer opportunities for the discovery and optimisation of natural products. Here we developed a new assembly strategy based on type IIS endonucleases and elaborate synthetic DNA platforms, which could be used to seamlessly assemble and engineer biosynthetic gene clusters (BGCs). By applying this versatile tool, we designed and assembled more than thirty different artificial myxochromide BGCs, each around 30 kb in size, and established heterologous expression platforms using a derivative of Myxococcus xanthus DK1622 as a host. In addition to the five native types of myxochromides (A, B, C, D and S), novel lipopeptide structures were produced by combinatorial exchange of nonribosomal peptide synthetase (NRPS) encoding genes from different myxochromide BGCs. Inspired by the evolutionary diversification of the native myxochromide megasynthetases, the ancestral A-type NRPS was engineered by inactivation, deletion, or duplication of catalytic domains and successfully converted into functional B-, C- and D-type megasynthetases. The constructional design approach applied in this study enables combinatorial engineering of complex synthetic BGCs and has great potential for the exploitation of other natural product biosynthetic pathways.
  • Biosynthesis of Branched Alkoxy Groups: Iterative Methyl Group Alkylation by a Cobalamin-Dependent Radical SAM Enzyme.

    Wang, Yuanyou; Schnell, Bastien; Baumann, Sascha; Müller, Rolf; Begley, Tadhg P; HIPS, Helmholtz-Institut füt Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (2017-02-08)
    The biosynthesis of branched alkoxy groups, such as the unique t-butyl group found in a variety of natural products, is still poorly understood. Recently, cystobactamids were isolated and identified from Cystobacter sp as novel antibacterials. These metabolites contain an isopropyl group proposed to be formed using CysS, a cobalamin-dependent radical S-adenosylmethionine (SAM) methyltransferase. Here, we reconstitute the CysS-catalyzed reaction, on p-aminobenzoate thioester substrates, and demonstrate that it not only catalyzes sequential methylations of a methyl group to form ethyl and isopropyl groups but remarkably also sec-butyl and t-butyl groups. To our knowledge, this is the first in vitro reconstitution of a cobalamin-dependent radical SAM enzyme catalyzing the conversion of a methyl group to a t-butyl group.
  • New Alpiniamides From sp. IB2014/011-12 Assembled by an Unusual Hybrid Non-ribosomal Peptide Synthetase -AT Polyketide Synthase Enzyme.

    Paulus, Constanze; Rebets, Yuriy; Zapp, Josef; Rückert, Christian; Kalinowski, Jörn; Luzhetskyy, Andriy; HIPS, Helmholtz-Institut füt Pharmazeutische Forschung Saarland, Universitätscampus E8.1 66123 Saarbrücken, Germany. (2018-01-01)
    he environment of Lake Baikal is a well-known source of microbial diversity. The strain Streptomyces sp. IB2014/011-12, isolated from samples collected at Lake Baikal, was found to exhibit potent activity against Gram-positive bacteria. Here, we report isolation and characterization of linear polyketide alpiniamide A (1) and its new derivatives B–D (2–5). The structures of alpiniamides A–D were established and their relative configuration was determined by combination of partial Murata’s method and ROESY experiment. The absolute configuration of alpiniamide A was established through Mosher’s method. The gene cluster, responsible for the biosynthesis of alpiniamides (alp) has been identified by genome mining and gene deletion experiments. The successful expression of the cloned alp gene cluster in a heterologous host supports these findings. Analysis of the architecture of the alp gene cluster and the feeding of labeled precursors elucidated the alpiniamide biosynthetic pathway. The biosynthesis of alpiniamides is an example of a rather simple polyketide assembly line generating unusual chemical diversity through the combination of domain/module skipping and double bond migration events.
  • Zirconyl Clindamycinphosphate Antibiotic Nanocarriers for Targeting Intracellular Persisting

    Heck, Joachim G.; Rox, Katharina; Lünsdorf, Heinrich; Lückerath, Thorsten; Klaassen, Nicole; Medina, Eva; Goldmann, Oliver; Feldmann, Claus; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany.
    [ZrO]2+[CLP]2– (CLP: clindamycinphosphate) inorganic–organic hybrid nanoparticles (IOH-NPs) represent a novel strategy to treat persisting, recurrent infections with multiresistant Staphylococcus aureus. [ZrO]2+[CLP]2– is prepared in water and contains the approved antibiotic with unprecedented high load (82 wt % CLP per nanoparticle). The IOH-NPs result in 70–150-times higher antibiotic concentrations at difficult-to-reach infection sites, offering new options for improved drug delivery for chronic and difficult-to-treat infections.
  • Future Directions of Marine Myxobacterial Natural Product Discovery Inferred from Metagenomics.

    Garcia, Ronald; La Clair, James J; Müller, Rolf; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus 8.1, 66123 Saarbrücken, Germany. (2018-08-29)
    Over the last two decades, halophilic (organisms that thrive at high salt concentrations) and halotolerant (organisms that have adapted to high salt concentrations) myxobacteria emerged as an important source of structurally diverse secondary metabolites from the marine environment. This review explores the advance of metagenomics analysis and 16S rRNA gene phylogeny of the cultured and uncultured myxobacteria from marine and other salt-environments up to July 2018. The diversity of novel groups of myxobacteria in these environments appears unprecedented, especially in the
  • Self-resistance guided genome mining uncovers new topoisomerase inhibitors from myxobacteria.

    Panter, Fabian; Krug, Daniel; Baumann, Sascha; Müller, Rolf; HIPS, Helmholtz-Institute für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2018-06-07)
    There is astounding discrepancy between the genome-inscribed production capacity and the set of known secondary metabolite classes from many microorganisms as detected under laboratory cultivation conditions. Genome-mining techniques are meant to fill this gap, but in order to favor discovery of structurally novel as well as bioactive compounds it is crucial to amend genomics-based strategies with selective filtering principles. In this study, we followed a self-resistance guided approach aiming at the discovery of inhibitors of topoisomerase, known as valid target in both cancer and antibiotic therapy. A common host self-defense mechanism against such inhibitors in bacteria is mediated by so-called pentapeptide repeat proteins (PRP). Genes encoding the biosynthetic machinery for production of an alleged topoisomerase inhibitor were found on the basis of their collocation adjacent to a predicted PRP in the genome of the myxobacterium
  • Multi-Omics and Targeted Approaches to Determine the Role of Cellular Proteases in Protein Secretion.

    Busche, Tobias; Tsolis, Konstantinos C; Koepff, Joachim; Rebets, Yuriy; Rückert, Christian; Hamed, Mohamed B; Bleidt, Arne; Wiechert, Wolfgang; Lopatniuk, Mariia; Yousra, Ahmed; Anné, Jozef; Karamanou, Spyridoula; Oldiges, Marco; Kalinowski, Jörn; Luzhetskyy, Andriy; Economou, Anastassios; HIPS, Helmholtz-Institut für pharmazeutische Forschung Saarland, Universitätscampus 8.1, 66123 Saarbrücken, Germany. (2018-01-01)
  • A fluorescence anisotropy assay to discover and characterize ligands targeting the maytansine site of tubulin.

    Menchon, Grégory; Prota, Andrea E; Lucena-Agell, Daniel; Bucher, Pascal; Jansen, Rolf; Irschik, Herbert; Müller, Rolf; Paterson, Ian; Díaz, J Fernando; Altmann, Karl-Heinz; Steinmetz, Michel O; Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2018-05-29)
    Microtubule-targeting agents (MTAs) like taxol and vinblastine are among the most successful chemotherapeutic drugs against cancer. Here, we describe a fluorescence anisotropy-based assay that specifically probes for ligands targeting the recently discovered maytansine site of tubulin. Using this assay, we have determined the dissociation constants of known maytansine site ligands, including the pharmacologically active degradation product of the clinical antibody-drug conjugate trastuzumab emtansine. In addition, we discovered that the two natural products spongistatin-1 and disorazole Z with established cellular potency bind to the maytansine site on β-tubulin. The high-resolution crystal structures of spongistatin-1 and disorazole Z in complex with tubulin allowed the definition of an additional sub-site adjacent to the pocket shared by all maytansine-site ligands, which could be exploitable as a distinct, separate target site for small molecules. Our study provides a basis for the discovery and development of next-generation MTAs for the treatment of cancer.
  • Changed Expression of Cytoskeleton Proteins During Lung Injury in a Mouse Model of Infection.

    Ferrer-Navarro, Mario; Strehlitz, Anja; Medina, Eva; Vila, Jordi
    Infections by are a major cause of morbidity and mortality worldwide, often causing community-acquired pneumonia, otitis media and also bacteremia and meningitis. Studies on are mainly focused on its virulence or capacity to evade the host immune system, but little is known about the injury caused in lungs during a pneumococcal infection. Herein we investigated this issue comparing the proteome profile of lungs from infected mice with control mice by means of difference gel electrophoresis (DIGE) technology. In order to obtain reliable results three biological replicas were used, and four technical replicas were carried out in each biological replica. Proteomic comparison was performed at two time points: 24 and 48 h post infection. A total of 91 proteins were identified with different abundance. We found important changes in the protein profiles during pneumococcal infection mainly associated with regulation of vesicle-mediated transport, wound healing, and cytoskeleton organization. In conclusion, the results obtained show that the cytoskeleton of the host cell is modified in infection.
  • Discovery of recombinases enables genome mining of cryptic biosynthetic gene clusters in Burkholderiales species.

    Wang, Xue; Zhou, Haibo; Chen, Hanna; Jing, Xiaoshu; Zheng, Wentao; Li, Ruijuan; Sun, Tao; Liu, Jiaqi; Fu, Jun; Huo, Liujie; Li, Yue-Zhong; Shen, Yuemao; Ding, Xiaoming; Müller, Rolf; Bian, Xiaoying; Zhang, Youming; HIPS, Helmholtz-Institute für pharmazeutische Forschung Saarland, Universitätscampus E8.1, 66123 Saarbrücken, Germany. (2018-05-01)
    Bacterial genomes encode numerous cryptic biosynthetic gene clusters (BGCs) that represent a largely untapped source of drugs or pesticides. Mining of the cryptic products is limited by the unavailability of streamlined genetic tools in native producers. Precise genome engineering using bacteriophage recombinases is particularly useful for genome mining. However, recombinases are usually host-specific. The genome-guided discovery of novel recombinases and their transient expression could boost cryptic BGC mining. Herein, we reported a genetic system employing Red recombinases from Burkholderiales strain DSM 7029 for efficient genome engineering in several Burkholderiales species that currently lack effective genetic tools. Using specialized recombinases-assisted in situ insertion of functional promoters, we successfully mined five cryptic nonribosomal peptide synthetase/polyketide synthase BGCs, two of which were silent. Two classes of lipopeptides, glidopeptins and rhizomides, were identified through extensive spectroscopic characterization. This recombinase expression strategy offers utility within other bacteria species, allowing bioprospecting for potentially scalable discovery of novel metabolites with attractive bioactivities.

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