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1	The regulatory network controlling natural competence for DNA uptake in Vibrio cholerae Antonova, Elena S. 02 April 2013 (has links) The bacterial pathogen Vibrio cholerae is responsible for ongoing cholera outbreaks in Haiti and elsewhere. Association of V. cholerae with the human host is responsible for fatal disease, but the bacteria also reside as natural inhabitants of aquatic environments, commonly attaching as biofilms to chitinous surfaces of copepods and crabs. Prior studies in V. cholerae demonstrated that competence for genetic transformation, a mechanism of horizontal gene transfer (HGT), requires the TfoX regulator protein that is triggered by chitin, and the HapR transcription factor that is made in response to quorum sensing (QS) signals produced by V. cholerae and Vibrios. To define regulatory components connecting extracellular signals to natural competence, I first demonstrated that QS molecules produced by Vibrios within multi-species chitinous biofilms are required for DNA uptake by V. cholerae, confirming the critical role of QS signals in HGT. Second, I identified by transposon-mutagenesis a new positive regulator of competence, CytR (cytidine repressor), only studied prior in E. coli as a regulator of nucleoside scavenging. Specific mutations in V. cholerae CytR impaired expression of competence genes and halted DNA uptake; and the addition of exogenous cytidine had similar affects as predicted in E. coli. V. cholerae and other competent Vibrios encode TfoX, HapR, and CytR, although none of these regulators directly controls genes coding for the DNA uptake apparatus. Thus, these results have uncovered a regulatory network, likely used by many Vibrios, that contains additional factors linking several extracellular chemical molecules (cytidine, chitin, and QS signals) to DNA uptake. My study has begun to define a molecular mechanism by which both environment and genetics contribute to genome evolution for this important marine pathogen. Natural competence HGT Chitin Signaling molecules Vibrio cholerae Quorum sensing Cholera Genetic transformation Bacterial transformation
2	Vývoj rychlé metody cílené mutageneze bakterie Streptococcus zooepidemicus / Development of a fast method for site-directed mutagenesis in Streptococcus zooepidemicus Černý, Zbyněk January 2016 (has links) This diploma thesis is focused on development of a fast method for site-directed gene mutagenesis in Streptococcus zooepidemicus based on the mechanism of natural competence. Several genes were selected based on experimental data which highly probably influence hyaluronic acid synthesis. The deletion of the selected genes from genomic DNA was performed as proof of concept, and the resulting recombinant strains were characterized regarding changes of hyaluronic acid precursor concentrations (glucuronic acid and N-acetylglucosamin) in time of cultivation and the end production of hyaluronic acid.
3	Komparative Genomanalyse zur Stammoptimierung produktionsnaher Bacillus-Stämme / Comparative genome analysis of production-related Bacillus strains Wollherr, Antje 26 October 2010 (has links) No description available. 570 Biowissenschaften, Biologie Biology (incl. Psychology) Komparative Genomik Bacillus licheniformis Genomanalyse Proteasenproduktion Optimalgenom natürliche Kompetenz Kompetenzsystem Bakterien DNA-Aufnahme Pan Genom Core Genom Ortholo comparative genomics Bacillus licheniformis genomic analysis protease production optimal genome natural competence bacteria dna uptake pan genome core genome orthologous gene 42.30 54.99 WD 500: Bioinformatik {Biologie} WF 61

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