Project description:Identification of the specific WalR (YycF) binding regions on the B. subtilis chromosome during exponential and phosphate starvation growth phases. The data serves to extend the WalRK regulon in Bacillus subtilis and its role in cell wall metabolism, as well as implying a role in several other cellular processes.
Project description:The general assumption is that when bacteria run out of nutrients they become dormant or form spores. Here we show, using a new technique, that under deep starvation conditions non-sporulating Bacillus subtilis cells do not become dormant but continue to grow. B. subtilis can form (endo)spores and this has been regarded as the principal mechanism through which it survives long periods of nutrient depletion. However, in this study we demonstrate that non-sporulating B. subtilis cells can survive deep starvation conditions for many months. During this period, cells adopt an almost coccoid shape and become tolerant to antibiotics and oxidative stress. Interestingly, these cells appeared to be metabolically active, and transcriptome analyses indicated that their gene-expression profile differs substantially from both stationary phase cells, and exponentially growing cells. Surprisingly, using an inhibitor for cell division, we discovered that these coccoid-like B. subtilis cells are not dormant but actually grow and divide, albeit with a doubling time of ~4 days. It emerged that secreted proteases, allowing acquisition of nutrients from lysed brethren, are essential for this growth mode. In fact, nutrient levels comparable to 10,000 times diluted LB (Lysogeny broth) appeared to be sufficient to sustain this growth. The very slow growth provides an alternative strategy for B. subtilis to survive nutrient depletion and environmental stresses. We propose to call this the oligotrophic growth state. This state might be common among bacterial species to survive deep starvation conditions.
Project description:Bacillus subtilis is exposed to a wide range of transitory stress and starvation conditions. Here we investigate the expression changes observed in the B. subtilis wild type strain 168 and its isogenic sigB mutant(BSM29) with respect to each stress condition tested.
Project description:Identification of the specific WalR (YycF) binding regions on the B. subtilis chromosome during exponential and phosphate starvation growth phases. The data serves to extend the WalRK regulon in Bacillus subtilis and its role in cell wall metabolism, as well as implying a role in several other cellular processes. For each sample analyzed in this study three biological replicates were performed. Three different samples were taken from a strain expressing the WalR-SPA protein as well as from wild-type (168) without a tagged WalR. Samples were taken from exponentially growing cells in low phosphate medium (LPDM) as well as from phosphate-limited cells (T2). Each sample compares ChIP DNA vs. Total DNA from the same cells.
Project description:In this study, temporal changes in the proteome, transcriptome and extracellular metabolome of B. subtilis caused by glucose starvation were monitored. For proteomic profiling, a combination of in vivo metabolic labeling and shot gun mass spectrometric analysis was carried out for five different proteomic subfractions (i. cytosolic, ii. extracellular, iii. membrane, iv. integral membrane, and v. surface proteome fraction) leading to the identification of about 52% of the predicted proteome of B. subtilis. Acquired proteomic and transcriptomic data were analyzed using Voronoi treemaps which link functional classifications and relative expression changes of gene products according to their fate in the stationary phase. The data obtained enables for in-depth analysis of major physiological processes including protein degradation and is the first comprehensive profiling of changes in the membrane subfraction. Cells were grown in a minimal medium with glucose and L-malate (0.05 % each) to induce glucose starvation after growth to an OD500 of 1.0. Samples were taken at different time points along the growth curve (exponential growth, transition phase, transition phase +30, +60 and +120 minutes). Microarray hybridizations were performed with RNA from two biological replicates. The individual samples were labeled with Cy5; a reference pool containing equal amounts of RNA from all 10 samples was labeled with Cy3.
Project description:Bacillus subtilis responds to phosphate starvation stress by inducing the PhoP and SigB regulons. While the PhoP regulon provides a specific response to phosphate starvation stress, maximizing the acquisition of phosphate (Pi) from the environment and reducing the cellular requirement for this essential nutrient, the SigB regulon provide non-specific resistance to stress by protecting essential cellular components such as DNA and membranes. We have characterized the phosphate starvation stress response of B. subtilis at a genome-wide level using DNA macroarrays. A combination of outlier and cluster analyses identified putatively new members of the PhoP regulon, namely yfkN (2',3'-cyclic-nucleotide 2'-phosphodiesterase), yurI (ribonuclease), yjdB (unknown) and vpr (extracellular serine protease). YurI is thought to be responsible for the non-specific degradation of RNA, whilst the activity of YfkN on various nucleotide phosphates suggests that it could act on substrates liberated by YurI which produces 3` or 5` phosphoribonucleotides. The putative new PhoP regulon members are either known or predicted to be secreted and are likely to be important for the recovery of inorganic phosphate from a variety of organic sources of phosphate in the environment. Keywords: other
Project description:In this study, temporal changes in the proteome, transcriptome and extracellular metabolome of B. subtilis caused by glucose starvation were monitored. For proteomic profiling, a combination of in vivo metabolic labeling and shot gun mass spectrometric analysis was carried out for five different proteomic subfractions (i. cytosolic, ii. extracellular, iii. membrane, iv. integral membrane, and v. surface proteome fraction) leading to the identification of about 52% of the predicted proteome of B. subtilis. Acquired proteomic and transcriptomic data were analyzed using Voronoi treemaps which link functional classifications and relative expression changes of gene products according to their fate in the stationary phase. The data obtained enables for in-depth analysis of major physiological processes including protein degradation and is the first comprehensive profiling of changes in the membrane subfraction.
Project description:Bacillus subtilis is exposed to a wide range of transitory stress and starvation conditions. Here we investigate the expression changes observed in the B. subtilis wild type strain 168 and its isogenic sigB mutant(BSM29) with respect to each stress condition tested. Gene expression was queried for the stress conditions: ethanol-, butanol-, osmotic- and oxidative stress, heat shock, low temperature growth, glucose as well as oxygen limitation. For butanol-, ethanol-, osmotic-, and oxidative stress as well as heat shock : time points (0min, 5min, 10min, 15min and 20min) ; for glucose limitation and oxygen limitation : time points (0min, 15min, 30min, 45min, 60min or 90min) and for low temperature growth, samples for recording of expression values were taken during mid-exponential growth at OD540 0.9 and 1.0.