Project description:We measured steady-state transcript levels in 1) wild-type E. litoralis DSM 8509, 2) a nepR-ecfG deletion strain (ΔnepR-ecfG), 3) a phyR deletion strain (ΔphyR), 4) a lovK-lovR deletion strain (ΔlovKR), and 5) a gsrK-gsrP deletion strain (ΔgsrKΔgsrP) cultivated in constant white light or in constant dark conditions.
Project description:To unravel the adaptation strategies of D. shibae to anaerobic conditions in microaerobic to anaerobic parts of the ocean and to define the underlying regulatory network an anaerobic shift experiment in Salt-Water-Medium in a chemostate was established. Transcriptome analyses were used to investigate the physiological status of D. shibae under this conditions. Dinoroseobacter shibae wild type strain DSM 16493T was grown in a chemostate in saltwater mininmal medium (SWM) mimicking the conditions in the marine habitat under anaerobic conditions. For growth under oxygen depletion the media were supplemented with 50 mM KNO3 to sustain anaerobic respiration. Therefore, D. shibae was grown aerobically in the chemostate until the culture reached the exponential phase, than countinuously cultivaion was started. The dilution rate was 0.1 h-1, establishing the approximate half-maximum growth rate of D. shibae in the exponential phase. The anaerobic shift was initialised after 20 hours by stopping the aeration. The samples were harvested before (as reference) and 30 minutes after stopping the airation. Three biological replica were analyzed. Comparison: Identification of genes induced or repressed under aerobic conditions in the Dinoroseobacter shibae wild type strain DSM 16493T. Here we compared the transcriptome profile of D. shibae wild type strain DSM 16493T grown aerobically in the chemostate in exponential phase with the transcriptome profile of the D. shibae wild type strain DSM 16493T which was grown without aeration for 5, 10, 15, 20, 30, 60 and 120 min.
Project description:Streptococcus gallolyticus subsp. gallolyticus is a commensal of the human gastrointestinal tract and a pathogen of infective endocarditis and other biofilm-associated infections with exposed collagen. Therefore, this study focuses on the characterization of the biofilm formation and collagen adhesion of S. gallolyticus subsp. gallolyticus under different conditions. It has been observed that lysozyme triggers biofilm formation divergently in the analyzed S. gallolyticus subsp. gallolyticus strains. The transcriptome analysis was performed for two strains which form more biofilm in the presence of lysozyme. Lysozyme leads to higher expression of genes of transcription and translation, of the dlt operon (cell wall modification), of hydrogen peroxide resistance proteins and of two immunity proteins which could be involved in biofilm formation. Furthermore, the adhesion ability of 73 different S. gallolyticus subsp. gallolyticus strains to collagen type I and IV was analyzed. High adhesion ability was observed for the strain UCN 34, whereas the strain DSM 16831 adhered only marginally to collagen. The full genome microarray analysis revealed strain-dependent gene expression due to adhesion. The expression of genes of a transposon and a phage region in strain DSM 16831 were increased, which corresponds to lateral gene transfer. Adherence to collagen leads to a change in the expression of genes of nutrients uptake in the strain UCN 34.
