Recent Submissions

  • Rapid paracellular transmigration of Campylobacter jejuni across polarized epithelial cells without affecting TER: role of proteolytic-active HtrA cleaving E-cadherin but not fibronectin

    Boehm, Manja; Hoy, Benjamin; Rohde, Manfred; Tegtmeyer, Nicole; Bæk, Kristoffer T; Oyarzabal, Omar A; Brøndsted, Lone; Wessler, Silja; Backert, Steffen (2012-04-25)
    Abstract Background Campylobacter jejuni is one of the most important bacterial pathogens causing food-borne illness worldwide. Crossing the intestinal epithelial barrier and host cell entry by C. jejuni is considered the primary reason of damage to the intestinal tissue, but the molecular mechanisms as well as major bacterial and host cell factors involved in this process are still widely unclear. Results In the present study, we characterized the serine protease HtrA (high-temperature requirement A) of C. jejuni as a secreted virulence factor with important proteolytic functions. Infection studies and in vitro cleavage assays showed that C. jejuni’s HtrA triggers shedding of the extracellular E-cadherin NTF domain (90 kDa) of non-polarised INT-407 and polarized MKN-28 epithelial cells, but fibronectin was not cleaved as seen for H. pylori’s HtrA. Deletion of the htrA gene in C. jejuni or expression of a protease-deficient S197A point mutant did not lead to loss of flagella or reduced bacterial motility, but led to severe defects in E-cadherin cleavage and transmigration of the bacteria across polarized MKN-28 cell layers. Unlike other highly invasive pathogens, transmigration across polarized cells by wild-type C. jejuni is highly efficient and is achieved within a few minutes of infection. Interestingly, E-cadherin cleavage by C. jejuni occurs in a limited fashion and transmigration required the intact flagella as well as HtrA protease activity, but does not reduce transepithelial electrical resistance (TER) as seen with Salmonella, Shigella, Listeria or Neisseria. Conclusion These results suggest that HtrA-mediated E-cadherin cleavage is involved in rapid crossing of the epithelial barrier by C. jejuni via a very specific mechanism using the paracellular route to reach basolateral surfaces, but does not cleave the fibronectin receptor which is necessary for cell entry.
  • Host-derived extracellular RNA promotes adhesion of Streptococcus pneumoniae to endothelial and epithelial cells.

    Zakrzewicz, Dariusz; Bergmann, Simone; Didiasova, Miroslava; Giaimo, Benedetto Daniele; Borggrefe, Tilman; Mieth, Maren; Hocke, Andreas C; Lochnit, Guenter; Schaefer, Liliana; Hammerschmidt, Sven; et al. (2016-11-28)
    Streptococcus pneumoniae is the most frequent cause of community-acquired pneumonia. The infection process involves bacterial cell surface receptors, which interact with host extracellular matrix components to facilitate colonization and dissemination of bacteria. Here, we investigated the role of host-derived extracellular RNA (eRNA) in the process of pneumococcal alveolar epithelial cell infection. Our study demonstrates that eRNA dose-dependently increased S. pneumoniae invasion of alveolar epithelial cells. Extracellular enolase (Eno), a plasminogen (Plg) receptor, was identified as a novel eRNA-binding protein on S. pneumoniae surface, and six Eno eRNA-binding sites including a C-terminal 15 amino acid motif containing lysine residue 434 were characterized. Although the substitution of lysine 434 for glycine (K434G) markedly diminished the binding of eRNA to Eno, the adherence to and internalization into alveolar epithelial cells of S. pneumoniae strain carrying the C-terminal lysine deletion and the mutation of internal Plg-binding motif were only marginally impaired. Accordingly, using a mass spectrometric approach, we identified seven novel eRNA-binding proteins in pneumococcal cell wall. Given the high number of eRNA-interacting proteins on pneumococci, treatment with RNase1 completely inhibited eRNA-mediated pneumococcal alveolar epithelial cell infection. Our data support further efforts to employ RNAse1 as an antimicrobial agent to combat pneumococcal infectious diseases.
  • Biofilm formation by Salmonella enterica serovar Typhimurium colonizing solid tumours.

    Crull, Katja; Rohde, Manfred; Westphal, Kathrin; Loessner, Holger; Wolf, Kathrin; Felipe-López, Alfonso; Hensel, Michael; Weiss, Siegfried (2011-08)
    Systemic administration of Salmonella enterica serovar Typhimurium to tumour bearing mice results in preferential colonization of the tumours and retardation of tumour growth. Although the bacteria are able to invade the tumour cells in vitro, in tumours they were never detected intracellularly. Ultrastructural analysis of Salmonella-colonized tumours revealed that the bacteria had formed biofilms. Interestingly, depletion of neutrophilic granulocytes drastically reduced biofilm formation. Obviously, bacteria form biofilms in response to the immune reactions of the host. Importantly, we tested Salmonella mutants that were no longer able to form biofilms by deleting central regulators of biofilm formation. Such bacteria could be observed intracellularly in immune cells of the host or in tumour cells. Thus, tumour colonizing S. typhimurium might form biofilms as protection against phagocytosis. Since other bacteria are behaving similarly, solid murine tumours might represent a unique model to study biofilm formation in vivo.
  • Differences in the aromatic domain of homologous streptococcal fibronectin-binding proteins trigger different cell invasion mechanisms and survival rates.

    Rohde, Manfred; Graham, Rikki M; Branitzki-Heinemann, Katja; Borchers, Patricia; Preuss, Claudia; Schleicher, Ina; Zähner, Dorothea; Talay, Susanne R; Fulde, Marcus; Dinkla, Katrin; et al. (2011-03)
    Group A streptococci (GAS, Streptococcus pyogenes) and Group G streptococci (GGS, Streptococcus dysgalactiae ssp. equisimilis) adhere to and invade host cells by binding to fibronectin. The fibronectin-binding protein SfbI from GAS acts as an invasin by using a caveolae-mediated mechanism. In the present study we have identified a fibronectin-binding protein, GfbA, from GGS, which functions as an adhesin and invasin. Although there is a high degree of similarity in the C-terminal sequence of SfbI and GfbA, the invasion mechanisms are different. Unlike caveolae-mediated invasion by SfbI-expressing GAS, the GfbA-expressing GGS isolate trigger cytoskeleton rearrangements. Heterologous expression of GfbA on the surface of a commensal Streptococcus gordonii and purified recombinant protein also triggered actin rearrangements. Expression of a truncated GfbA (lacking the aromatic domain) and chimeric GfbA/SfbI protein (replacing the aromatic domain of SfbI with the GfbA aromatic domain) on S. gordonii or recombinant proteins alone showed that the aromatic domain of GfbA is responsible for different invasion mechanisms. This is the first evidence for a biological function of the aromatic domain of fibronectin-binding proteins. Furthermore, we show that streptococci invading via cytoskeleton rearrangements and intracellular trafficking along the classical endocytic pathway are less persistence than streptococci entering via caveolae.
  • The M1 protein of Streptococcus pyogenes triggers an innate uptake mechanism into polarized human endothelial cells.

    Ochel, Anja; Rohde, Manfred; Chhatwal, Gursharan S; Talay, Susanne R; Helmholtz Centre for infection research, Inhoffenstr. 7, 38124 Braunschweíg, Germany. (2014)
    Serotype M1 Streptococcus pyogenes is a major human pathogen associated with severe invasive diseases causing high morbidity and mortality. In a substantial number of cases, invasive disease develops in previously healthy individuals with no obvious port of entry. This has led to the hypothesis that the source of streptococci in these cases is a transient bacteraemia. This study focuses on the analysis of interaction of tissue-invasive serotype M1 S. pyogenes with human endothelial cells (EC) of the vascular system. We identify the M1 surface protein of S. pyogenes as the EC invasin which is recognised by polarized human blood EC, thereby triggering rapid, phagocytosis-like uptake of streptococci into polarized EC layers. Upon internalization, the M1 S. pyogenes serotype is incorporated into phagosomes which traffic via the endosomal/lysosomal pathway. However, some of the streptococci successfully evade this innate killing process and hereby mediate their escape into the cytoplasm of the host cell. The results of this study demonstrate that blood EC possess an efficient uptake mechanism for serotype M1 S. pyogenes. Despite efficient phagocytosis, streptococcal survival within EC constitutes one potential mechanism which favours intracellular persistence and thus facilitates continuous infection and dissemination from the primary side of infection into deep tissue.
  • Increased neutrophil extracellular trap-mediated Staphylococcus aureus clearance through inhibition of nuclease activity by clindamycin and immunoglobulin.

    Schilcher, Katrin; Andreoni, Federica; Uchiyama, Satoshi; Ogawa, Taiji; Schuepbach, Reto A; Zinkernagel, Annelies S; Helmholtz Centre for infection reseach, Inhoffenstr. 7, 38124 Braunschweig, Germany. (2014-08-01)
    The Gram-positive human pathogen Staphylococcus aureus causes a variety of human diseases such as skin infections, pneumonia, and endocarditis. The micrococcal nuclease Nuc1 is one of the major S. aureus virulence factors and allows the bacterium to avoid neutrophil extracellular trap (NET)-mediated killing. We found that addition of the protein synthesis inhibitor clindamycin to S. aureus LAC cultures decreased nuc1 transcription and subsequently blunted nuclease activity in a molecular beacon-based fluorescence assay. We also observed reduced NET degradation through Nuc1 inhibition translating into increased NET-mediated clearance. Similarly, pooled human immunoglobulin specifically inhibited nuclease activity in a concentration-dependent manner. Inhibition of nuclease activity by clindamycin and immunoglobulin enhanced S. aureus clearance and should be considered in the treatment of S. aureus infections.
  • Kroppenstedtia eburnea gen. nov., sp. nov., a thermoactinomycete isolated by environmental screening, and emended description of the family Thermoactinomycetaceae Matsuo et al. 2006 emend. Yassin et al. 2009.

    von Jan, Mathias; Riegger, Nicole; Pötter, Gabriele; Schumann, Peter; Verbarg, Susanne; Spröer, Cathrin; Rohde, Manfred; Lauer, Bettina; Labeda, David P; Klenk, Hans-Peter (2011-09)
    A Gram-positive, spore-forming, aerobic, filamentous bacterium, strain JFMB-ATE(T), was isolated in 2008 during environmental screening of a plastic surface in grade C in a contract manufacturing organization in southern Germany. The isolate grew at temperatures of 25-50 °C and at pH 5.0-8.5, forming ivory-coloured colonies with sparse white aerial mycelia. Chemotaxonomic and molecular characteristics of the isolate matched those described for members of the family Thermoactinomycetaceae, except that the cell-wall peptidoglycan contained LL-diaminopimelic acid, while all previously described members of this family display this diagnostic diamino acid in meso-conformation. The DNA G+C content of the novel strain was 54.6 mol%, the main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol, and the major menaquinone was MK-7. The major fatty acids had saturated C₁₄-C₁₆ branched chains. No diagnostic sugars were detected. Based on the chemotaxonomic results and 16S rRNA gene sequence analysis, the isolate is proposed to represent a novel genus and species, Kroppenstedtia eburnea gen. nov. sp. nov. The type strain is JFMB-ATE(T) ( = DSM 45196(T)  = NRRL B-24804(T)  = CCUG 59226(T)).
  • microscopy

    Rohde, Manfred (Elsevier, 2011)
  • An optimized in vitro blood-brain barrier model reveals bidirectional transmigration of African trypanosome strains.

    Untucht, Christopher; Rasch, Janine; Fuchs, Elena; Rohde, Manfred; Bergmann, Simone; Steinert, Michael (2011-10)
    The transmigration of African trypanosomes across the human blood-brain barrier (BBB) is the critical step during the course of human African trypanosomiasis. The parasites Trypanosoma brucei gambiense and T. b. rhodesiense are transmitted to humans during the bite of tsetse flies. Trypanosomes multiply within the bloodstream and finally invade the central nervous system (CNS), which leads to the death of untreated patients. This project focused on the mechanisms of trypanosomal traversal across the BBB. In order to establish a suitable in vitro BBB model for parasite transmigration, different human cell lines were used, including ECV304, HBMEC and HUVEC, as well as C6 rat astrocytes. Validation of the BBB models with Escherichia coli HB101 and E. coli K1 revealed that a combination of ECV304 cells seeded on Matrigel as a semi-synthetic basement membrane and C6 astrocytes resulted in an optimal BBB model system. The BBB model showed selective permeability for the pathogenic E. coli K1 strain, and African trypanosomes were able to traverse the optimized ECV304-C6 BBB efficiently. Furthermore, coincubation indicated that paracellular macrophage transmigration does not facilitate trypanosomal BBB traversal. An inverse assembly of the BBB model demonstrated that trypanosomes were also able to transmigrate the optimized ECV304-C6 BBB backwards, indicating the relevance of the CNS as a possible reservoir of a relapsing parasitaemia.
  • Complete genome sequence of Desulfarculus baarsii type strain (2st14).

    Sun, Hui; Spring, Stefan; Lapidus, Alla; Davenport, Karen; Del Rio, Tijana Glavina; Tice, Hope; Nolan, Matt; Copeland, Alex; Cheng, Jan-Fang; Lucas, Susan; et al. (2010)
    Desulfarculus baarsii (Widdel 1981) Kuever et al. 2006 is the type and only species of the genus Desulfarculus, which represents the family Desulfarculaceae and the order Desulfarculales. This species is a mesophilic sulfate-reducing bacterium with the capability to oxidize acetate and fatty acids of up to 18 carbon atoms completely to CO(2). The acetyl-CoA/CODH (Wood-Ljungdahl) pathway is used by this species for the complete oxidation of carbon sources and autotrophic growth on formate. The type strain 2st14(T) was isolated from a ditch sediment collected near the University of Konstanz, Germany. This is the first completed genome sequence of a member of the order Desulfarculales. The 3,655,731 bp long single replicon genome with its 3,303 protein-coding and 52 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Geodermatophilus obscurus type strain (G-20).

    Ivanova, Natalia; Sikorski, Johannes; Jando, Marlen; Munk, Christine; Lapidus, Alla; Glavina Del Rio, Tijana; Copeland, Alex; Tice, Hope; Cheng, Jan-Fang; Lucas, Susan; et al. (2010)
    Geodermatophilus obscurus Luedemann 1968 is the type species of the genus, which is the type genus of the family Geodermatophilaceae. G. obscurus is of interest as it has frequently been isolated from stressful environments such as rock varnish in deserts, and as it exhibits interesting phenotypes such as lytic capability of yeast cell walls, UV-C resistance, strong production of extracellular functional amyloid (FuBA) and manganese oxidation. This is the first completed genome sequence of the family Geodermatophilaceae. The 5,322,497 bp long genome with its 5,161 protein-coding and 58 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Brachyspira murdochii type strain (56-150).

    Pati, Amrita; Sikorski, Johannes; Gronow, Sabine; Munk, Christine; Lapidus, Alla; Copeland, Alex; Glavina Del Tio, Tijana; Nolan, Matt; Lucas, Susan; Chen, Feng; et al. (2010)
    Brachyspira murdochii Stanton et al. 1992 is a non-pathogenic, host-associated spirochete of the family Brachyspiraceae. Initially isolated from the intestinal content of a healthy swine, the 'group B spirochaetes' were first described as Serpulina murdochii. Members of the family Brachyspiraceae are of great phylogenetic interest because of the extremely isolated location of this family within the phylum 'Spirochaetes'. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first completed genome sequence of a type strain of a member of the family Brachyspiraceae and only the second genome sequence from a member of the genus Brachyspira. The 3,241,804 bp long genome with its 2,893 protein-coding and 40 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Planctomyces limnophilus type strain (Mü 290).

    Labutti, Kurt; Sikorski, Johannes; Schneider, Susanne; Nolan, Matt; Lucas, Susan; Glavina Del Rio, Tijana; Tice, Hope; Cheng, Jan-Fang; Goodwin, Lynne; Pitluck, Sam; et al. (2010)
    Planctomyces limnophilus Hirsch and Müller 1986 belongs to the order Planctomycetales, which differs from other bacterial taxa by several distinctive features such as internal cell compartmentalization, multiplication by forming buds directly from the spherical, ovoid or pear-shaped mother cell and a cell wall which is stabilized by a proteinaceous layer rather than a peptidoglycan layer. Besides Pirellula staleyi, this is the second completed genome sequence of the family Planctomycetaceae. P. limnophilus is of interest because it differs from Pirellula by the presence of a stalk and its structure of fibril bundles, its cell shape and size, the formation of multicellular rosettes, low salt tolerance and red pigmented colonies. The 5,460,085 bp long genome with its 4,304 protein-coding and 66 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Nakamurella multipartita type strain (Y-104).

    Tice, Hope; Mayilraj, Shanmugam; Sims, David; Lapidus, Alla; Nolan, Matt; Lucas, Susan; Glavina Del Rio, Tijana; Copeland, Alex; Cheng, Jan-Fang; Meincke, Linda; et al. (2010)
    Nakamurella multipartita (Yoshimi et al. 1996) Tao et al. 2004 is the type species of the monospecific genus Nakamurella in the actinobacterial suborder Frankineae. The nonmotile, coccus-shaped strain was isolated from activated sludge acclimated with sugar-containing synthetic wastewater, and is capable of accumulating large amounts of polysaccharides in its cells. Here we describe the features of the organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of a member of the family Nakamurellaceae. The 6,060,298 bp long single replicon genome with its 5415 protein-coding and 56 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Chitinophaga pinensis type strain (UQM 2034).

    Glavina Del Rio, Tijana; Abt, Birte; Spring, Stefan; Lapidus, Alla; Nolan, Matt; Tice, Hope; Copeland, Alex; Cheng, Jan-Fang; Chen, Feng; Bruce, David; et al. (2010)
    Chitinophaga pinensis Sangkhobol and Skerman 1981 is the type strain of the species which is the type species of the rapidly growing genus Chitinophaga in the sphingobacterial family 'Chitinophagaceae'. Members of the genus Chitinophaga vary in shape between filaments and spherical bodies without the production of a fruiting body, produce myxospores, and are of special interest for their ability to degrade chitin. Here we describe the features of this organism, together with the complete genome sequence, and annotation. This is the first complete genome sequence of a member of the family 'Chitinophagaceae', and the 9,127,347 bp long single replicon genome with its 7,397 protein-coding and 95 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Thermocrinis albus type strain (HI 11/12).

    Wirth, Reinhard; Sikorski, Johannes; Brambilla, Evelyne; Misra, Monica; Lapidus, Alla; Copeland, Alex; Nolan, Matt; Lucas, Susan; Chen, Feng; Tice, Hope; et al. (2010)
    Thermocrinis albus Eder and Huber 2002 is one of three species in the genus Thermocrinis in the family Aquificaceae. Members of this family have become of significant interest because of their involvement in global biogeochemical cycles in high-temperature ecosystems. This interest had already spurred several genome sequencing projects for members of the family. We here report the first completed genome sequence a member of the genus Thermocrinis and the first type strain genome from a member of the family Aquificaceae. The 1,500,577 bp long genome with its 1,603 protein-coding and 47 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Methanoplanus petrolearius type strain (SEBR 4847).

    Brambilla, Evelyne; Djao, Olivier Duplex Ngatchou; Daligault, Hajnalka; Lapidus, Alla; Lucas, Susan; Hammon, Nancy; Nolan, Matt; Tice, Hope; Cheng, Jan-Fang; Han, Cliff; et al. (2010)
    Methanoplanus petrolearius Ollivier et al. 1998 is the type strain of the genus Methanoplanus. The strain was originally isolated from an offshore oil field from the Gulf of Guinea. Members of the genus Methanoplanus are of interest because they play an important role in the carbon cycle and also because of their significant contribution to the global warming by methane emission in the atmosphere. Like other archaea of the family Methanomicrobiales, the members of the genus Methanoplanus are able to use CO(2) and H(2) as a source of carbon and energy; acetate is required for growth and probably also serves as carbon source. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of a member of the family Methanomicrobiaceae and the sixth complete genome sequence from the order Methanomicrobiales. The 2,843,290 bp long genome with its 2,824 protein-coding and 57 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Sulfurimonas autotrophica type strain (OK10).

    Sikorski, Johannes; Munk, Christine; Lapidus, Alla; Ngatchou Djao, Olivier Duplex; Lucas, Susan; Glavina Del Rio, Tijana; Nolan, Matt; Tice, Hope; Han, Cliff; Cheng, Jan-Fang; et al. (2010)
    Sulfurimonas autotrophica Inagaki et al. 2003 is the type species of the genus Sulfurimonas. This genus is of interest because of its significant contribution to the global sulfur cycle as it oxidizes sulfur compounds to sulfate and by its apparent habitation of deep-sea hydrothermal and marine sulfidic environments as potential ecological niche. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the second complete genome sequence of the genus Sulfurimonas and the 15(th) genome in the family Helicobacteraceae. The 2,153,198 bp long genome with its 2,165 protein-coding and 55 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Thermaerobacter marianensis type strain (7p75a).

    Han, Cliff; Gu, Wei; Zhang, Xiaojing; Lapidus, Alla; Nolan, Matt; Copeland, Alex; Lucas, Susan; Del Rio, Tijana Glavina; Tice, Hope; Cheng, Jan-Fang; et al. (2010)
    Thermaerobacter marianensis Takai et al. 1999 is the type species of the genus Thermaerobacter, which belongs to the Clostridiales family Incertae Sedis XVII. The species is of special interest because T. marianensis is an aerobic, thermophilic marine bacterium, originally isolated from the deepest part in the western Pacific Ocean (Mariana Trench) at the depth of 10.897m. Interestingly, the taxonomic status of the genus has not been clarified until now. The genus Thermaerobacter may represent a very deep group within the Firmicutes or potentially a novel phylum. The 2,844,696 bp long genome with its 2,375 protein-coding and 60 RNA genes consists of one circular chromosome and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.
  • Complete genome sequence of Thermobispora bispora type strain (R51).

    Liolios, Konstantinos; Sikorski, Johannes; Jando, Marlen; Lapidus, Alla; Copeland, Alex; Glavina, Tijana; Del Rio; Nolan, Matt; Lucas, Susan; Tice, Hope; et al. (2010)
    Thermobispora bispora (Henssen 1957) Wang et al. 1996 is the type species of the genus Thermobispora. This genus is of great interest because it is strictly thermophilic and because it has been shown for several of its members that the genome contains substantially distinct (6.4% sequence difference) and transcriptionally active 16S rRNA genes. Here we describe the features of this organism, together with the complete genome sequence and annotation. This is the second completed genome sequence of a member from the suborder Streptosporangineae and the first genome sequence of a member of the genus Thermobispora. The 4,189,976 bp long genome with its 3,596 protein-coding and 63 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

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