Project description:Comparison of gene expression profile of the whiB4 mutant strain of Mycobacterium tuberculosis with the wild type Mycobacterium tuberculosis H37RV Mtb WhiB4 mutant mRNA was compared with the mRNA of wtMtb H37RV under aerobic conditons
Project description:Phagosome acidification is one of the challenges faced by Mycobacterium tuberculosis during infection. This intracellular pathogen is known to adapt to its stressful environment though stress response pathways and by secreting proteins to modify the host immune response for survival and proliferation. However, M. tuberculosis also holds the potential to form viable but non-replicating (VBNR) and antibiotic tolerant persisters in response to environmental stress, including acid stress. In this study we used a in vitro acid stress model to stimulate the formation of a VBNR subpopulation in a M. tuberculosis clinical isolate with an increased propensity to form VBNR bacteria. Mass spectrometry-based proteomics was used to characterize the cellular proteome and culture filtrate proteome of actively replicating (pH 6,5) and VBNR enriched (pH 4,5) cultures. We show that in response to acid stress, M. tuberculosis S169 increases the expression of known stress response proteins, including the methyltransferase Rv1405c and the acid stress response two-component regulatory protein TcrX. Interestingly, we found that the dormancy response regulon components were less abundant in acid stressed M. tuberculosis S169. Our protein aggregation capture culture filtrate proteomic approach revealed that the culture filtrates of low pH stressed M. tuberculosis S169 contained less proteins than that of actively replicating cultures. We identified several proteins previously implicated in M. tuberculosis persistence, including toxin-antitoxin proteins (VapC51 and VapB10), the chorismate mutase (Rv1885c), and several uncharacterized proteins. The observed differences identified in the characterisation of this clinical isolate in comparison to published M. tuberculosis H37Rv highlights the need to investigate M. tuberculosis clinical isolates for a more representative understanding of the tuberculosis stress response.
Project description:Phagosome acidification is one of the challenges faced by Mycobacterium tuberculosis during infection. This intracellular pathogen is known to adapt to its stressful environment though stress response pathways and by secreting proteins to modify the host immune response for survival and proliferation. However, M. tuberculosis also holds the potential to form viable but non-replicating (VBNR) and antibiotic tolerant persisters in response to environmental stress, including acid stress. In this study we used a in vitro acid stress model to stimulate the formation of a VBNR subpopulation in a M. tuberculosis clinical isolate with an increased propensity to form VBNR bacteria. Mass spectrometry-based proteomics was used to characterize the cellular proteome and culture filtrate proteome of actively replicating (pH 6,5) and VBNR enriched (pH 4,5) cultures. We show that in response to acid stress, M. tuberculosis S169 increases the expression of known stress response proteins, including the methyltransferase Rv1405c and the acid stress response two-component regulatory protein TcrX. Interestingly, we found that the dormancy response regulon components were less abundant in acid stressed M. tuberculosis S169. Our protein aggregation capture culture filtrate proteomic approach revealed that the culture filtrates of low pH stressed M. tuberculosis S169 contained less proteins than that of actively replicating cultures. We identified several proteins previously implicated in M. tuberculosis persistence, including toxin-antitoxin proteins (VapC51 and VapB10), the chorismate mutase (Rv1885c), and several uncharacterized proteins. The observed differences identified in the characterisation of this clinical isolate in comparison to published M. tuberculosis H37Rv highlights the need to investigate M. tuberculosis clinical isolates for a more representative understanding of the tuberculosis stress response.
Project description:Transcriptional profiling of SirR and manganese regulated expression of genes in Mycobacterium tuberculosis strains comparing high manganese vs. low manganese in Rv (wild type Mycobacterium tuberculosis) and ST70 (mntR mutant strain of Mycobacterium tuberculosis)
Project description:We report the effects of VapC21 overexpression on Mycobacterium tuberculosis H37Rv strain. The total RNA was isolated from M. tuberculosis harboring either pTetR-int or pTetR-Int-vapC21 the expression was induced with 50 ng/ml anhydrotetracycline for 24 hrs. We report the effect of deletion VapC21 on the transciptional profile of Mycobacterium tuberculosis Erdman strain. For RNA-seq analysis, total RNA was isolated from mid-log phase culture of either parental or △vapC21 mutant strain.