Gunka, Katrin

[["dc.bibliographiccitation.artnumber","e51196"],["dc.bibliographiccitation.issue","83"],["dc.bibliographiccitation.journal","Journal of Visualized Experiments"],["dc.contributor.author","Stannek, Lorena"],["dc.contributor.author","Egelkamp, Richard"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Commichau, Fabian M."],["dc.date.accessioned","2018-11-07T09:45:24Z"],["dc.date.available","2018-11-07T09:45:24Z"],["dc.date.issued","2014"],["dc.description.abstract","Many microorganisms such as bacteria proliferate extremely fast and the populations may reach high cell densities. Small fractions of cells in a population always have accumulated mutations that are either detrimental or beneficial for the cell. If the fitness effect of a mutation provides the subpopulation with a strong selective growth advantage, the individuals of this subpopulation may rapidly outcompete and even completely eliminate their immediate fellows. Thus, small genetic changes and selection-driven accumulation of cells that have acquired beneficial mutations may lead to a complete shift of the genotype of a cell population. Here we present a procedure to monitor the rapid clonal expansion and elimination of beneficial and detrimental mutations, respectively, in a bacterial cell population over time by cocultivation of fluorescently labeled individuals of the Gram-positive model bacterium Bacillus subtilis. The method is easy to perform and very illustrative to display intraspecies competition among the individuals in a bacterial cell population."],["dc.identifier.doi","10.3791/51196"],["dc.identifier.isi","000348513500062"],["dc.identifier.pmid","24473333"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/34610"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Journal Of Visualized Experiments"],["dc.relation.issn","1940-087X"],["dc.title","Monitoring Intraspecies Competition in a Bacterial Cell Population by Cocultivation of Fluorescently Labelled Strains"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","515"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Journal of Bacteriology"],["dc.bibliographiccitation.lastpage","526"],["dc.bibliographiccitation.volume","196"],["dc.contributor.author","Zaprasis, Adrienne"],["dc.contributor.author","Hoffmann, Tamara"],["dc.contributor.author","Stannek, Lorena"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Commichau, Fabian M."],["dc.contributor.author","Bremer, Erhard"],["dc.date.accessioned","2018-11-07T09:44:02Z"],["dc.date.available","2018-11-07T09:44:02Z"],["dc.date.issued","2014"],["dc.description.abstract","PutP and OpuE serve as proline transporters when this imino acid is used by Bacillus subtilis as a nutrient or as an osmostress protectant, respectively. The simultaneous inactivation of the PutP and OpuE systems still allows the utilization of proline as a nutrient. This growth phenotype pointed to the presence of a third proline transport system in B. subtilis. We took advantage of the sensitivity of a putP opuE double mutant to the toxic proline analog 3,4-dehydro-DL-proline (DHP) to identify this additional proline uptake system. DHP-resistant mutants were selected and found to be defective in the use of proline as a nutrient. Whole-genome resequencing of one of these strains provided the lead that the inactivation of the gamma-aminobutyrate (GABA) transporter GabP was responsible for these phenotypes. DNA sequencing of the gabP gene in 14 additionally analyzed DHP-resistant strains confirmed this finding. Consistently, each of the DHP-resistant mutants was defective not only in the use of proline as a nutrient but also in the use of GABA as a nitrogen source. The same phenotype resulted from the targeted deletion of the gabP gene in a putP opuE mutant strain. Hence, the GabP carrier not only serves as an uptake system for GABA but also functions as the third proline transporter of B. subtilis. Uptake studies with radiolabeled GABA and proline confirmed this conclusion and provided information on the kinetic parameters of the GabP carrier for both of these substrates."],["dc.identifier.doi","10.1128/JB.01128-13"],["dc.identifier.isi","000332625000001"],["dc.identifier.pmid","24142252"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/34307"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Soc Microbiology"],["dc.relation.issn","1098-5530"],["dc.relation.issn","0021-9193"],["dc.title","The gamma-Aminobutyrate Permease GabP Serves as the Third Proline Transporter of Bacillus subtilis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","354"],["dc.bibliographiccitation.journal","Microbiology"],["dc.bibliographiccitation.lastpage","361"],["dc.bibliographiccitation.volume","161"],["dc.contributor.author","Dormeyer, Miriam"],["dc.contributor.author","Egelkamp, Richard"],["dc.contributor.author","Thiele, Martin J."],["dc.contributor.author","Hammer, Elke"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Stannek, Lorena"],["dc.contributor.author","Voelker, Uwe"],["dc.contributor.author","Commichau, Fabian M."],["dc.date.accessioned","2018-11-07T10:01:11Z"],["dc.date.available","2018-11-07T10:01:11Z"],["dc.date.issued","2015"],["dc.description.abstract","Bacillus subtilis is a Gram-positive bacterium that is easy to manipulate genetically. Several methods for genome engineering have been developed that helped to extend our understanding of how the B. subtilis cell operates. Consequently, the bacterium has become one of the best-studied organisms. B. subtilis has also been engineered for industrial applications. Moreover, great progress has been achieved in promoter engineering to improve the performance of production strains. To expand the toolbox for engineering B. subtilis, we have constructed a system for the inducer-free activation of gene expression. The system relies on spontaneous mutational activation of a cryptic promoter and selection-driven enrichment of bacteria harbouring the mutated promoter. The synthetic promoter is cryptic due to a perfect direct repeat, separating the binding motifs of the RNA polymerase housekeeping sigma factor. The promoter can be fused to genes for industrial applications and to a growth-promoting gene that, upon mutational activation of the promoter, allows enrichment of the engineered bacteria due to a selective growth advantage."],["dc.identifier.doi","10.1099/mic.0.000001"],["dc.identifier.isi","000356647800012"],["dc.identifier.pmid","25473090"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37961"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1350-0872"],["dc.title","novel engineering tool in the Bacillus subtilis toolbox: inducer-free activation of gene expression by selection-driven promoter decryptification"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3379"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Environmental Microbiology"],["dc.bibliographiccitation.lastpage","3390"],["dc.bibliographiccitation.volume","17"],["dc.contributor.author","Stannek, Lorena"],["dc.contributor.author","Thiele, Martin J."],["dc.contributor.author","Ischebeck, Till"],["dc.contributor.author","Gunka, Katrin"],["dc.contributor.author","Hammer, Elke"],["dc.contributor.author","Voelker, Uwe"],["dc.contributor.author","Commichau, Fabian M."],["dc.date.accessioned","2018-11-07T09:52:29Z"],["dc.date.available","2018-11-07T09:52:29Z"],["dc.date.issued","2015"],["dc.description.abstract","In the Gram-positive bacterium, Bacillus subtilis glutamate is synthesized by the glutamine synthetase and the glutamate synthase (GOGAT). During growth with carbon sources that exert carbon catabolite repression, the rocG glutamate dehydrogenase (GDH) gene is repressed and the transcription factor GltC activates the expression of the GOGAT encoding gltAB genes. In the presence of amino acids of the glutamate family, the GDH RocG is synthesized and the enzyme prevents GltC from binding to DNA. The dual control of glutamate biosynthesis allows the efficient utilization of the available nutrients. Here we provide genetic and biochemical evidence that, like RocG, also the paralogous GDH GudB can inhibit the transcription factor GltC, thereby controlling glutamate biosynthesis. Contradictory previous observations show that high level of GDH activity does not result in permanent inhibition of GltC. By controlling the intracellular levels of glutamate through feeding with exogenous arginine, we observed that the GDH-dependent control of GltC and thus expression of the gltAB genes inversely correlates with the glutamate pool. These results suggest that the B.subtilisGDHs RocG and GudB in fact act as glutamate sensors. In conclusion, the GDH-mediated control of glutamate biosynthesis seems to depend on the intracellular glutamate concentration."],["dc.identifier.doi","10.1111/1462-2920.12813"],["dc.identifier.isi","000361000500022"],["dc.identifier.pmid","25711804"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36136"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Wiley-blackwell"],["dc.relation.issn","1462-2920"],["dc.relation.issn","1462-2912"],["dc.title","Evidence for synergistic control of glutamate biosynthesis by glutamate dehydrogenases and glutamate in Bacillus subtilis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]