The Experts below are selected from a list of 1533 Experts worldwide ranked by ideXlab platform

Friedrich Gotz - One of the best experts on this subject based on the ideXlab platform.

  • Staphylococcus Carnosus: from starter culture to protein engineering platform
    Applied Microbiology and Biotechnology, 2017
    Co-Authors: John Löfblom, Minh Thu Nguyen, Ralf Rosenstein, Stefan Stahl, Friedrich Gotz
    Abstract:

    Since the 1950s, Staphylococcus Carnosus is used as a starter culture for sausage fermentation where it contributes to food safety, flavor, and a controlled fermentation process. The long experience with S. Carnosus has shown that it is a harmless and “food grade” species. This was confirmed by the genome sequence of S. Carnosus TM300 that lacks genes involved in pathogenicity. Since the development of a cloning system in TM300, numerous genes have been cloned, expressed, and characterized and in particular, virulence genes that could be functionally validated in this non-pathogenic strain. A secretion system was developed for production and secretion of industrially important proteins and later modified to also enable display of heterologous proteins on the surface. The display system has been employed for various purposes, such as development of live bacterial delivery vehicles as well as microbial biocatalysts or bioadsorbents for potential environmental or biosensor applications. Recently, this surface display system has been utilized for display of peptide and protein libraries for profiling of protease substrates and for generation of various affinity proteins, e.g., Affibody molecules and scFv antibodies. In addition, by display of fragmented antigen-encoding genes, the surface expression system has been successfully used for epitope mapping of antibodies. Reviews on specific applications of S. Carnosus have been published earlier, but here we provide a more extensive overview, covering a broad range of areas from food fermentation to sophisticated methods for protein-based drug discovery, which are all based on S. Carnosus .

  • secretome analysis revealed adaptive and non adaptive responses of the Staphylococcus Carnosus femb mutant
    Proteomics, 2015
    Co-Authors: Mulugeta Nega, Ralf Rosenstein, Linda Dube, Melanie Kull, Annekathrin Ziebandt, Patrick Ebner, Dirk Albrecht, Bernhard Krismer, Michael Hecker, Friedrich Gotz
    Abstract:

    FemABX peptidyl transferases are involved in non-ribosomal pentaglycine interpeptide bridge biosynthesis. Here, we characterized the phenotype of a Staphylococcus Carnosus femB deletion mutant, which was affected in growth and showed pleiotropic effects such as enhanced methicillin sensitivity, lysostaphin resistance, cell clustering, and decreased peptidoglycan cross-linking. However, comparative secretome analysis revealed a most striking difference in the massive secretion or release of proteins into the culture supernatant in the femB mutant than the wild type. The secreted proteins can be categorized into typical cytosolic proteins and various murein hydrolases. As the transcription of the murein hydrolase genes was up-regulated in the mutant, they most likely represent an adaption response to the life threatening mutation. Even though the transcription of the cytosolic protein genes was unaltered, their high abundance in the supernatant of the mutant is most likely due to membrane leakage triggered by the weakened murein sacculus and enhanced autolysins.

  • nitrate oxygen co sensing by an nrea nreb sensor complex of Staphylococcus Carnosus
    Molecular Microbiology, 2014
    Co-Authors: Stephanie Nilkens, Friedrich Gotz, Mareike Kochsingenstreu, Volker Niemann, Thilo Stehle, Gottfried Unden
    Abstract:

    Summary In Staphylococci maximal induction of nitrate reductase (narGHJI genes) requires anaerobic conditions, the presence of nitrate, and the NreABC regulatory system. Aerobic regulation is effected by the NreB/NreC two-component system. The role of the nitrate receptor NreA in nitrate induction and its relation to aerobic regulation was analysed in Staphylococcus Carnosus. Nitrate induction of a narG-lip reporter gene required presence of NreB/NreC. When nreA was deleted, nitrate was no longer required for maximal induction, suggesting that NreA is a nitrate regulated inhibitor of NreB/NreC. In vitro, NreA and mutant NreA(Y95A) decreased NreB phosphorylation in part or completely, which was due to the inhibition of the autophosphorylating activity rather than an increase of phosphatase activity. Inhibition of phosphorylation was relieved completely when the nitrate-bound NreA was used instead of the nitrate-free form. In the bacterial two-hybrid BACTH system and HPINE interaction assays, NreA interacted with NreB, but not with NreC, and the interaction was diminished by nitrate. In summary, NreA interacts with NreB and controls its phosphorylation level in a nitrate dependent manner. In this way nitrate and NreA modulate the function of the oxygen sensor NreB, resulting in nitrate/oxygen co-sensing by an NreA/NreB sensor unit as part of the NreABC-system.

  • Nitrate/oxygen co-sensing by an NreA/NreB sensor complex of Staphylococcus Carnosus
    Molecular Microbiology, 2013
    Co-Authors: Stephanie Nilkens, Friedrich Gotz, Volker Niemann, Thilo Stehle, Mareike Koch-singenstreu, Gottfried Unden
    Abstract:

    Summary In Staphylococci maximal induction of nitrate reductase (narGHJI genes) requires anaerobic conditions, the presence of nitrate, and the NreABC regulatory system. Aerobic regulation is effected by the NreB/NreC two-component system. The role of the nitrate receptor NreA in nitrate induction and its relation to aerobic regulation was analysed in Staphylococcus Carnosus. Nitrate induction of a narG-lip reporter gene required presence of NreB/NreC. When nreA was deleted, nitrate was no longer required for maximal induction, suggesting that NreA is a nitrate regulated inhibitor of NreB/NreC. In vitro, NreA and mutant NreA(Y95A) decreased NreB phosphorylation in part or completely, which was due to the inhibition of the autophosphorylating activity rather than an increase of phosphatase activity. Inhibition of phosphorylation was relieved completely when the nitrate-bound NreA was used instead of the nitrate-free form. In the bacterial two-hybrid BACTH system and HPINE interaction assays, NreA interacted with NreB, but not with NreC, and the interaction was diminished by nitrate. In summary, NreA interacts with NreB and controls its phosphorylation level in a nitrate dependent manner. In this way nitrate and NreA modulate the function of the oxygen sensor NreB, resulting in nitrate/oxygen co-sensing by an NreA/NreB sensor unit as part of the NreABC-system.

  • genomic differences between the food grade Staphylococcus Carnosus and pathogenic staphylococcal species
    International Journal of Medical Microbiology, 2010
    Co-Authors: Ralf Rosenstein, Friedrich Gotz
    Abstract:

    By comparative analyses based on the newly sequenced genome of the meat starter bacterium Staphylococcus Carnosus TM300, we observed remarkable differences in the content of mobile genetic elements between non-pathogenic and pathogenic staphylococci. While the latter reveal highly flexible genomes with various mobile elements indicating frequent exchange and rearrangement of genomic material, S. Carnosus shows a conspicuous lack of those elements carrying only remnants of a prophage and a genomic island in its genome. Furthermore, the S. Carnosus genome is significantly poor in repetitive sequences. Despite being known as completely avirulent, S. Carnosus reveals also various gene products with similarity to proteins annotated as virulence factors in S. aureus. In addition, the genome carries a number of mutationally inactivated genes including those of the global regulatory systems agr and sae. Our data indicate that S. Carnosus has adapted to the constant environmental conditions encountered as part of a starter culture population by a reductive evolution leading to gene loss and inactivation.

Stefan Stahl - One of the best experts on this subject based on the ideXlab platform.

  • Staphylococcus Carnosus: from starter culture to protein engineering platform
    Applied Microbiology and Biotechnology, 2017
    Co-Authors: John Löfblom, Minh Thu Nguyen, Ralf Rosenstein, Stefan Stahl, Friedrich Gotz
    Abstract:

    Since the 1950s, Staphylococcus Carnosus is used as a starter culture for sausage fermentation where it contributes to food safety, flavor, and a controlled fermentation process. The long experience with S. Carnosus has shown that it is a harmless and “food grade” species. This was confirmed by the genome sequence of S. Carnosus TM300 that lacks genes involved in pathogenicity. Since the development of a cloning system in TM300, numerous genes have been cloned, expressed, and characterized and in particular, virulence genes that could be functionally validated in this non-pathogenic strain. A secretion system was developed for production and secretion of industrially important proteins and later modified to also enable display of heterologous proteins on the surface. The display system has been employed for various purposes, such as development of live bacterial delivery vehicles as well as microbial biocatalysts or bioadsorbents for potential environmental or biosensor applications. Recently, this surface display system has been utilized for display of peptide and protein libraries for profiling of protease substrates and for generation of various affinity proteins, e.g., Affibody molecules and scFv antibodies. In addition, by display of fragmented antigen-encoding genes, the surface expression system has been successfully used for epitope mapping of antibodies. Reviews on specific applications of S. Carnosus have been published earlier, but here we provide a more extensive overview, covering a broad range of areas from food fermentation to sophisticated methods for protein-based drug discovery, which are all based on S. Carnosus .

  • optimization of electroporation mediated transformation Staphylococcus Carnosus as model organism
    Journal of Applied Microbiology, 2007
    Co-Authors: John Löfblom, Stefan Stahl, Nina Kronqvist, Mathias Uhlen, Henrik Wernerus
    Abstract:

    The study was conducted with an aim to optimize the transformation efficiency of the Gram-positive bacterium Staphylococcus Carnosus to a level that would enable the creation of cell surface disp ...

  • general expression vectors for Staphylococcus Carnosus enabled efficient production of the outer membrane protein a of klebsiella pneumoniae
    Fems Microbiology Letters, 2002
    Co-Authors: Marianne Hansson, Patrik Samuelson, Thien Ngoc Nguyen, Stefan Stahl
    Abstract:

    General expression vectors, designed for intracellular expression or secretion of recombinant proteins in the non-pathogenic Staphylococcus Carnosus, were constructed. Both vector systems encode two different affinity tags, an upstream albumin binding protein and a downstream hexahistidyl peptide, and are furnished with cleavage sites for two site-specific proteases for optional affinity tag removal. To evaluate the novel vectors, the gene encoding the outer membrane protein A (OmpA) of Klebsiella pneumoniae was introduced into the vectors. Efficient production was demonstrated in both systems, although, as expected for OmpA fusions, somewhat better intracellularly, and the fusion proteins could be recovered as full-length products by affinity chromatography.

  • engineering of a Staphylococcus Carnosus surface display system by substitution or deletion of a Staphylococcus hyicus lipase propeptide
    Fems Microbiology Letters, 1999
    Co-Authors: Patrik Samuelson, Alain Robert, Francois Cano, Stefan Stahl
    Abstract:

    Surface display of recombinant proteins on bacteria and phages has become an important topic in bioscience. A system for the display of heterologous proteins on the surface of Staphylococcus Carnosus employs the secretion signal and propeptide from a Staphylococcus hyicus lipase for translocation and since the propeptide is of considerable size (207 amino acids) and not processed in S. Carnosus, we have investigated the possibility to delete or substitute the propeptide for smaller protein domains, to thereby improve the surface display system. A set of new vectors was constructed and the surface expression of model proteins was investigated by various methods, including fluorescence-activated cell sorting. The results suggest that the propeptide region indeed can be deleted when proteins which are easily secretable are displayed. In contrast, the propeptide seems to be advantageous for translocation of inefficiently secreted proteins. Moreover, our study also presents a rational strategy for how to monitor the engineering efforts for the optimization of a surface display system.

  • surface display of functional fibronectin binding domains on Staphylococcus Carnosus
    FEBS Letters, 1999
    Co-Authors: Sissela Liljeqvist, Mathias Uhlen, Francois Cano, Thien Ngoc Nguyen, Alain Robert, Stefan Stahl
    Abstract:

    Abstract The surface expression in Staphylococcus Carnosus of three different fibronectin binding domains (FNBDs), derived from fibronectin binding proteins of Streptococcus dysgalactiae and Staphylococcus aureus , has been investigated. Surface localization of the chimeric proteins containing the FNBDs was demonstrated. All three surface-displayed FNBDs were demonstrated to bind fibronectin in whole-cell enzyme-linked binding assays. Furthermore, for one of the constructs, intranasal immunizations with the recombinant bacteria resulted in improved antibody responses to a model immunogen present within the chimeric surface proteins. The implications of the results for the design of live bacterial vaccine delivery systems are discussed.

Walter P Hammes - One of the best experts on this subject based on the ideXlab platform.

  • Staphylococcus condimenti sp. nov., from soy sauce mash, and Staphylococcus Carnosus (Schleifer and Fischer 1982) subsp. utilis subsp. nov.
    International journal of systematic bacteriology, 1998
    Co-Authors: Andreas J Probst, Christian Hertel, Lothar Richter, Lars Wassill, Wolfgang Ludwig, Walter P Hammes
    Abstract:

    Based on the sequence data of 23S rRNA of Staphylococcus Carnosus, Staphylococcus piscifermentans, Staphylococcus aureus and Staphylococcus epidermidis, species-specific probes were constructed. Their application revealed a heterogeneity within 18 strains previously identified as S. Carnosus. Strains of this group were selected, and their 23S rRNA sequence was determined. It was revealed that the strains of S. Carnosus can be placed in at least three sub-groups. This grouping was supported by physiological data and DNA-DNA similarity studies. Based on these results, were propose the new species Staphylococcus condimenti sp. nov. The type strain is S. condimenti F-2T (=DSM 11674T). The phylogenetic position of the new species within the radiation of other staphylococcal strains is reflected by a 16S nRNA-based tree. Furthermore, it is proposed to designate the new subspecies of Staphylococcus Carnosus Schleifer and Fischer 1982, Staphylococcus Carnosus subsp. utilis subsp. nov. The type strain of S. Carnosus subsp. utilis is SK 11T (= DSM 11676T).

  • Staphylococcus condimenti sp nov from soy sauce mash and Staphylococcus Carnosus schleifer and fischer 1982 subsp utilis subsp nov
    International Journal of Systematic and Evolutionary Microbiology, 1998
    Co-Authors: Andreas J Probst, Christian Hertel, Lothar Richter, Lars Wassill, Wolfgang Ludwig, Walter P Hammes
    Abstract:

    Based on the sequence data of 23S rRNA of Staphylococcus Carnosus, Staphylococcus piscifermentans, Staphylococcus aureus and Staphylococcus epidermidis, species-specific probes were constructed. Their application revealed a heterogeneity within 18 strains previously identified as S. Carnosus. Strains of this group were selected, and their 23S rRNA sequence was determined. It was revealed that the strains of S. Carnosus can be placed in at least three sub-groups. This grouping was supported by physiological data and DNA-DNA similarity studies. Based on these results, we propose the new species Staphylococcus condimenti sp. nov. The type strain is S. condimenti F-2T (= DSM 11674T). The phylogenetic position of the new species within the radiation of other staphylococcal strains is reflected by a 16S rRNA-based tree. Furthermore, it is proposed to designate the new subspecies of Staphylococcus Carnosus Schleifer and Fischer 1982, Staphylococcus Carnosus subsp. utilis subsp. nov. The type strain of S. Carnosus subsp. utilis is SK 11T(= DSM 11676T).

  • reduction of nitrite by Staphylococcus Carnosus and Staphylococcus piscifermen tans
    Systematic and Applied Microbiology, 1995
    Co-Authors: Susanne Hartmann, Gudrun Wolf, Walter P Hammes
    Abstract:

    Summary Strains of Staphylococcus Carnosus and Staphylococcus pisciferatentans are employed in food fermentations. The organisms arc expected to perform among other desired reactions an effective reduction of nitrate and nitrite. We have investigated the potential to perform these reactions with resting cells of S. Carnosus (16 strains) and S. piscifermentans (10 strains). It was observed that all strains reduced nitrite and three strains that were investigated in more detail formed ammonia as the only metabolic end product. The reduction of nitrite was inhibited in the presence of nitrate, whereas neither amino acids nor ammonia exhibited an effect on the reaction. Nitrite and nitrate are used as terminal electron acceptors and support growth under anaerobic conditions as evidenced by the increase in growth yield. These data are consistent with a dissimilatory type of nitrite reduction.

R Talon - One of the best experts on this subject based on the ideXlab platform.

  • surface properties and behaviour on abiotic surfaces of Staphylococcus Carnosus a genetically homogeneous species
    Food Microbiology, 2007
    Co-Authors: Stella Planchon, Brigitte Gaillardmartinie, Sabine Leroy, Marienoelle Bellonfontaine, Silvina Fadda, R Talon
    Abstract:

    Abstract This work aimed to characterize the surface properties of Staphylococcus Carnosus and the influence of different media on their ability to adhere and grow on industrial supports. As their colonization could be dependant of the strain, the genetic diversity of the strains was studied. The diversity of 13 strains analysed by pulsed-field gel electrophoresis revealed that the S. Carnosus strains formed a homogeneous genetic group. Their surface properties, characterized by studying their affinity to solvents, were hydrophilic with a strong negative surface charge. The S. Carnosus strain CIT 833 hardly adhered to polytetrafluoroethylene (PTFE) and stainless steel chips. Tryptic soy broth (TSB) was the most favourable medium for growth on stainless steel support while TSB/NaCl was better for growth on PTFE. Scanning electron microscopy ( sem ) showed that this strain weakly colonized both supports and did not form cell aggregates. Indeed, the strain did not synthesize polysaccharides. These results showed that S. Carnosus adhered on different abiotic surfaces which are used in food factories but was not able to accumulate on these surfaces. The inability of S. Carnosus to form biofilm could explain why S. Carnosus is rarely isolated in meat processing environment.

  • decarboxylase activity involved in methyl ketone production by Staphylococcus Carnosus 833 a strain used in sausage fermentation
    Fems Microbiology Letters, 2002
    Co-Authors: S Fadda, Sabine Leroysetrin, A Lebert, R Talon
    Abstract:

    Staphylococcus Carnosus strain 833, inoculated into sausage, increased the levels of methyl ketones which contributed to the cured aroma. These ketones were predicted to arise from incomplete β-oxidation followed by a decarboxylation. To check this hypothesis, we measured the β-decarboxylase activity in resting cells of S. Carnosus grown in complex or in synthetic medium, using as substrate a β-ketoacid, which can be an intermediate of the β-oxidation pathway. This activity was present throughout the growth period. The enzyme appeared to be constitutive because no induction was observed. High aeration, a pH of 5 and the presence of nitrate promoted the production of methyl ketones.

  • characterization of catalase and superoxide dismutase in Staphylococcus Carnosus 833 strain
    Journal of Applied Microbiology, 2001
    Co-Authors: Charlotte Barriere, Sabine Leroysetrin, R Talon
    Abstract:

    Aims: Staphylococcus Carnosus, used as starter culture in fermented meat products, decreases the level of volatiles arising from lipid oxidation. To analyse its antioxidant capacities, catalase and superoxide dismutase (SOD) were characterized. Methods and Results: Catalase and SOD activities were measured with spectrophotometric methods and visualized on non-denaturing polyacrylamide gels. The corresponding sod gene was identified by PCR. Southern hybridizations and enzymatic analyses showed that there was a single catalase and a single SOD in Staph. Carnosus 833 strain. The gene encoding the Staph. Carnosus SOD was found to encode a protein closely related to SOD requiring manganese. Catalase and SOD levels increased in mid-log phase. Only catalase was induced by oxygen, nitrate or nitrite while glucose induced neither enzyme. Metal ion limitation increased catalase and decreased SOD activities. Conclusions: Staph. Carnosus synthesizes both enzymes in conditions encountered in sausage manufacturing. These results could explain the antioxidant properties of Staph. Carnosus starter culture. Significance and Impact of the Study: The knowledge of the antioxidant properties of Staphylococci will allow a more rational use of these starters in meat fermented products.

  • identification of β oxidation and thioesterase activities in Staphylococcus Carnosus 833 strain
    Fems Microbiology Letters, 2000
    Co-Authors: G Engelvin, Gilles Feron, C Perrin, Daniel Molle, R Talon
    Abstract:

    Staphylococcus Carnosus 833, inoculated into sausage meat, increased the level of methyl ketones, which contributed to the cured aroma. These ketones can arise from incomplete β-oxidation followed by two enzymatic activities: a thioesterase and a decarboxylase. In this study we identified the β-oxidative pathway (through the measure of 3-hydroxyacyl-CoA dehydrogenase activity) and the thioesterase activity in extracts of S. Carnosus cells grown in the presence of different methyl esters. The β-oxidative system was induced by methyl esters and highest induction was found with a 12-carbon substrate. It was specific for medium chain length fatty acyl CoA substrates. Its maximal activity was observed at the end of stationary growth phase. HPLC analyses of acyl-CoA after incubation of cell extracts with palmitoyl-CoA showed that the β-oxidation system released preferentially long chain hydroxyacyl-CoAs, enoyl-CoAs, and acyl-CoAs. The time-course of intermediate formation indicated a precursor–product relationship indicative of a model of free intermediates which could be further deacylated by a thioesterase. The thioesterase activity was enhanced when S. Carnosus was grown in the presence of methyl esters with at least 12 carbons and this enzyme was specific for short chain acyl-CoAs. The maximal activity was reached at the stationary growth phase.

Ralf Rosenstein - One of the best experts on this subject based on the ideXlab platform.

  • Staphylococcus Carnosus: from starter culture to protein engineering platform
    Applied Microbiology and Biotechnology, 2017
    Co-Authors: John Löfblom, Minh Thu Nguyen, Ralf Rosenstein, Stefan Stahl, Friedrich Gotz
    Abstract:

    Since the 1950s, Staphylococcus Carnosus is used as a starter culture for sausage fermentation where it contributes to food safety, flavor, and a controlled fermentation process. The long experience with S. Carnosus has shown that it is a harmless and “food grade” species. This was confirmed by the genome sequence of S. Carnosus TM300 that lacks genes involved in pathogenicity. Since the development of a cloning system in TM300, numerous genes have been cloned, expressed, and characterized and in particular, virulence genes that could be functionally validated in this non-pathogenic strain. A secretion system was developed for production and secretion of industrially important proteins and later modified to also enable display of heterologous proteins on the surface. The display system has been employed for various purposes, such as development of live bacterial delivery vehicles as well as microbial biocatalysts or bioadsorbents for potential environmental or biosensor applications. Recently, this surface display system has been utilized for display of peptide and protein libraries for profiling of protease substrates and for generation of various affinity proteins, e.g., Affibody molecules and scFv antibodies. In addition, by display of fragmented antigen-encoding genes, the surface expression system has been successfully used for epitope mapping of antibodies. Reviews on specific applications of S. Carnosus have been published earlier, but here we provide a more extensive overview, covering a broad range of areas from food fermentation to sophisticated methods for protein-based drug discovery, which are all based on S. Carnosus .

  • secretome analysis revealed adaptive and non adaptive responses of the Staphylococcus Carnosus femb mutant
    Proteomics, 2015
    Co-Authors: Mulugeta Nega, Ralf Rosenstein, Linda Dube, Melanie Kull, Annekathrin Ziebandt, Patrick Ebner, Dirk Albrecht, Bernhard Krismer, Michael Hecker, Friedrich Gotz
    Abstract:

    FemABX peptidyl transferases are involved in non-ribosomal pentaglycine interpeptide bridge biosynthesis. Here, we characterized the phenotype of a Staphylococcus Carnosus femB deletion mutant, which was affected in growth and showed pleiotropic effects such as enhanced methicillin sensitivity, lysostaphin resistance, cell clustering, and decreased peptidoglycan cross-linking. However, comparative secretome analysis revealed a most striking difference in the massive secretion or release of proteins into the culture supernatant in the femB mutant than the wild type. The secreted proteins can be categorized into typical cytosolic proteins and various murein hydrolases. As the transcription of the murein hydrolase genes was up-regulated in the mutant, they most likely represent an adaption response to the life threatening mutation. Even though the transcription of the cytosolic protein genes was unaltered, their high abundance in the supernatant of the mutant is most likely due to membrane leakage triggered by the weakened murein sacculus and enhanced autolysins.

  • genomic differences between the food grade Staphylococcus Carnosus and pathogenic staphylococcal species
    International Journal of Medical Microbiology, 2010
    Co-Authors: Ralf Rosenstein, Friedrich Gotz
    Abstract:

    By comparative analyses based on the newly sequenced genome of the meat starter bacterium Staphylococcus Carnosus TM300, we observed remarkable differences in the content of mobile genetic elements between non-pathogenic and pathogenic staphylococci. While the latter reveal highly flexible genomes with various mobile elements indicating frequent exchange and rearrangement of genomic material, S. Carnosus shows a conspicuous lack of those elements carrying only remnants of a prophage and a genomic island in its genome. Furthermore, the S. Carnosus genome is significantly poor in repetitive sequences. Despite being known as completely avirulent, S. Carnosus reveals also various gene products with similarity to proteins annotated as virulence factors in S. aureus. In addition, the genome carries a number of mutationally inactivated genes including those of the global regulatory systems agr and sae. Our data indicate that S. Carnosus has adapted to the constant environmental conditions encountered as part of a starter culture population by a reductive evolution leading to gene loss and inactivation.

  • genome analysis of the meat starter culture bacterium Staphylococcus Carnosus tm300
    Applied and Environmental Microbiology, 2009
    Co-Authors: Ralf Rosenstein, Christiane Nerz, Lalitha Biswas, Alexandra Resch, Guenter Raddatz, Stephan C Schuster, Friedrich Gotz
    Abstract:

    The Staphylococcus Carnosus genome has the highest GC content of all sequenced staphylococcal genomes, with 34.6%, and therefore represents a species that is set apart from S. aureus, S. epidermidis, S. saprophyticus, and S. haemolyticus. With only 2.56 Mbp, the genome belongs to a family of smaller staphylococcal genomes, and the ori and ter regions are asymmetrically arranged with the replichores I (1.05 Mbp) and II (1.5 Mbp). The events leading up to this asymmetry probably occurred not that long ago in evolution, as there was not enough time to approach the natural tendency of a physical balance. Unlike the genomes of pathogenic species, the TM300 genome does not contain mobile elements such as plasmids, insertion sequences, transposons, or STAR elements; also, the number of repeat sequences is markedly decreased, suggesting a comparatively high stability of the genome. While most S. aureus genomes contain several prophages and genomic islands, the TM300 genome contains only one prophage, ΦTM300, and one genomic island, νSCA1, which is characterized by a mosaic structure mainly composed of species-specific genes. Most of the metabolic core pathways are present in the genome. Some open reading frames are truncated, which reflects the nutrient-rich environment of the meat starter culture, making some functions dispensable. The genome is well equipped with all functions necessary for the starter culture, such as nitrate/nitrite reduction, various sugar degradation pathways, two catalases, and nine osmoprotection systems. The genome lacks most of the toxins typical of S. aureus as well as genes involved in biofilm formation, underscoring the nonpathogenic status.

  • cloning and expression of various staphylococcal genes encoding urease in Staphylococcus Carnosus
    Fems Microbiology Letters, 1991
    Co-Authors: Joachim Jose, Ralf Rosenstein, Friedrich Gotz, Stefan Christians, Heinrich Kaltwasser
    Abstract:

    The urease genes from Staphylococcus xylosus C2a, Staphylococcus aureus U500, and S. aureus Newman were cloned in Staphylococcus Carnosus using the plasmid vectors pCA43 and pCA44. The resulting respective recombinant plasmids pUra 402, pUraUH66, and pUra17 contained chromosomal DNA fragments with sizes of 5.6, 5.8, and 6.8 kb, respectively. Investigations on urease expression of the donor and recombinant strains in media with various nitrogen sources revealed that S. xylosus C2a produced urease constitutively at the highest specific activity. All of the recombinant strains had significantly lower urease activities than their DNA-donor strains. The nickel-dependence of urease was demonstrated in S. aureus U500 by a plate diffusion assay.