Phosphoproteomics of Mycobacterium tuberculosis DosR, DosS, and DosT
Ontology highlight
ABSTRACT:
ORGANISM(S): Mycobacterium Tuberculosis
SUBMITTER: Deepak Kaushal
PROVIDER: PXD015256 | JPOST Repository | Sat Aug 31 00:00:00 BST 2019
REPOSITORIES: jPOST
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Project description:The emergence of drug resistance among tuberculosis (TB) patients is often associated with their non-compliance to the length of the chemotherapy, which can reach up to 2 years for the treatment of multi-drug-resistant (MDR) TB. Drugs that would kill TB faster and would not lead to the development of drug resistance could shorten chemotherapy significantly. In Escherichia coli, the common mechanism of cell death by bactericidal antibiotics is the generation of highly reactive hydroxyl radicals via the Fenton reaction. Since ascorbic acid (vitamin C) is known to drive the Fenton reaction, we tested whether the Fenton reaction could lead to a bactericidal event in Mycobacterium tuberculosis by treating M. tuberculosis cultures with vitamin C. Here, we report that the addition of vitamin C to drug-susceptible, MDR and extensively drug-resistant (XDR) M. tuberculosis strains results in sterilization of the cultures in vitro. We show that the sterilizing effect of vitamin C on M. tuberculosis was dependent on the production of high ferrous ion levels and reactive oxygen species. Although, this potent sterilizing activity of vitamin C against M. tuberculosis in vitro was not observed in mice, we believe this activity needs further investigation.
2013-05-24 | GSE42293 | GEO
Project description:To survive a dynamic host environment, Mycobacterium tuberculosis must endure a series of challenges from reactive oxygen and nitrogen stress, to drastic shifts in oxygen availability. The mycobacterial Lsr2 protein has been implicated in reactive oxygen defense via direct protection of DNA. To examine the role of Lsr2 in pathogenesis and physiology of M. tuberculosis, we generated a strain deleted for lsr2. Analysis of the M. tuberculosis ?lsr2 strain demonstrated that Lsr2 is not required for DNA protection, as this strain was as equally susceptible as the wild-type to DNA-damaging agents. The lsr2 mutant did display severe growth defects under normoxic and hyperoxic conditions, but was not required for growth under low oxygen conditions. However, it was also required for adaptation to anaerobiosis. The defect in anaerobic adaptation led to a marked decrease in viability during, as well as a lag in recovery from, anaerobiosis. Gene expression profiling of ?lsr2 under aerobic and anaerobic conditions in conjunction with published DNA binding-site data indicate that Lsr2 is a global transcriptional regulator controlling adaptation to changing oxygen levels. The ?lsr2 strain was capable of establishing an early infection in the Balb/c mouse model; however, it was severely defective in persisting in the lungs and caused no discernible lung pathology. These findings demonstrate M. tuberculosis Lsr2 is a global transcriptional regulator required for control of genes involved in adaptation to extremes in oxygen availability and is required for persistent infection. Wild type H37Rv or lsr2 mutant strains were grown aerobically or in a Rach dormancy model in dubos tween albumin media and analyzed. Alternately, either aerobically grown or Rach model hypoxic samples were challenged with H2O2 samples and harvested 1h later. Experiments were repeated in triplicate or quadruplicate.
2014-05-24 | E-GEOD-57948 | biostudies-arrayexpress
Project description:Tuberculosis remains one of the most difficult to control infectious diseases in the world. Many different factors contribute to the complexity of this disease. These include the ability of the host to control the infection which may directly relate to nutritional status, presence of co-morbidities and genetic predisposition. Pathogen factors, in particular the ability of different Mycobacterium tuberculosis strains to respond to the harsh environment of the host granuloma, which includes low oxygen and nutrient availability and the presence of damaging radical oxygen and nitrogen species, also play an important role in the success of different strains to cause disease. In this study we evaluate the impact of a naturally occurring 12 gene 15 Kb genomic deletion on the physiology and virulence of M. tuberculosis. The strains denominated ON-A WT (wild type) and ON-A NM (natural mutant) were isolated from a previously reported TB outbreak in an inner city under-housed population in Toronto, Canada. Here we subjected these isogenic strains to transcriptomic (via RNA-seq) and proteomic analyses and identified several gene clusters with differential expression in the natural mutant, including the DosR regulon and the molybdenum cofactor biosynthesis genes, both of which were found in lower abundance in the natural mutant. We also demonstrated lesser virulence of the natural mutant in the guinea pig animal model. Overall, our findings suggest that the ON-A natural mutant is less fit to cause disease, supporting the general idea that even low virulent strains have the potential to cause extended transmission in at risk populations.
2018-04-23 | PXD005687 | Pride
Project description:Transcriptional profiling of H37Rv (WT), Mut1 and Comp1 bacteria under aerobic (Aer/0 day, i.e 0 D) and hypoxic conditions (Hyp/5 days standing culture, i.e 5 D). Mut1: H37Rv carrying devR gene disruption by in frame insertion of kanamycin resistance cassette and expressing DevRN-Kan fusion protein. Comp1: Mut1 complemented with low copy number plasmid carrying devR gene expressed from its native constitutive upstream promoter. (Reference: Majumdar et al., 2010, PLoS One 5:e9448). Goal is to compare transcriptional patterns of WT, Mut1 and Comp1 strains under aerobic (0 D) and hypoxic (5 D) conditions in vitro.
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Project description:The DosR regulon in Mycobacterium tuberculosis is involved in respiration-limiting conditions and its induction is controlled by two histidine kinases, DosS and DosT. Recent experimental evidence indicates DosS senses either molecular oxygen or a redox change. This report demonstrates that DosS responds to a reduced electron transport system (ETS), although this does not rule out a role for oxygen in silencing signaling. Under aerobic conditions induction of the DosR regulon by DosS but not DosT was observed after the addition of ascorbate, a powerful cytochrome c reductant, demonstrating DosS responds to a redox signal even in the presence of high oxygen tension. During hypoxic conditions regulon induction was attenuated by treatment with compounds that occluded electron flow into the menaquinone pool or decreased the size of the menaquinone pool itself. Increased regulon expression during hypoxia was observed when exogenous menaquinone was added, demonstrating the menaquinone pool is a limiting factor in regulon induction. Taken together these data indicate that a reduced menaquinone pool directly or indirectly triggers induction of the DosR regulon via DosS. Biochemical analysis of menaquinones upon entry into hypoxic/anaerobic conditions demonstrated the disappearance of the unsaturated species and low-level maintenance of the mono-saturated menaquinone. Relative to the unsaturated form, an analog of the saturated form is better able to induce signaling via DosS, rescue inhibition of menaquinone synthesis, and is less toxic. The menaquinone pool is central to the ETS and therefore provides a mechanistic link between the respiratory state of the bacilli and DosS signaling. Aerobically growing logarithmic phase DosS and DosT mutant strains were analyzed after treatment with the cytochrome c reductant ascorbate to examine the effect on DosR signaling caused by reducing the electron transport system. Experiments were repeated in triplicate (dosT mutant) or duplicate (dosS mutant).
2010-05-22 | E-GEOD-21963 | biostudies-arrayexpress
Project description:Transcriptional profiling of H37Rv (WT), Mut1 and Comp1 bacteria under aerobic (Aer/0 day, i.e 0 D) and hypoxic conditions (Hyp/5 days standing culture, i.e 5 D). Mut1: H37Rv carrying devR gene disruption by in frame insertion of kanamycin resistance cassette and expressing DevRN-Kan fusion protein. Comp1: Mut1 complemented with low copy number plasmid carrying devR gene expressed from its native constitutive upstream promoter. (Reference: Majumdar et al., 2010, PLoS One 5:e9448). Goal is to compare transcriptional patterns of WT, Mut1 and Comp1 strains under aerobic (0 D) and hypoxic (5 D) conditions in vitro. Two color and One-color experiments,Organism: Mycobacterium tuberculosis, Genotypic Technology designed Custom Mycobacterium tuberculosis H37Rv Whole Genome 8x15k GE Microarray (AMADID-020181)
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Project description:The emergence of drug resistance among tuberculosis (TB) patients is often associated with their non-compliance to the length of the chemotherapy, which can reach up to 2 years for the treatment of multi-drug-resistant (MDR) TB. Drugs that would kill TB faster and would not lead to the development of drug resistance could shorten chemotherapy significantly. In Escherichia coli, the common mechanism of cell death by bactericidal antibiotics is the generation of highly reactive hydroxyl radicals via the Fenton reaction. Since ascorbic acid (vitamin C) is known to drive the Fenton reaction, we tested whether the Fenton reaction could lead to a bactericidal event in Mycobacterium tuberculosis by treating M. tuberculosis cultures with vitamin C. Here, we report that the addition of vitamin C to drug-susceptible, MDR and extensively drug-resistant (XDR) M. tuberculosis strains results in sterilization of the cultures in vitro. We show that the sterilizing effect of vitamin C on M. tuberculosis was dependent on the production of high ferrous ion levels and reactive oxygen species. Although, this potent sterilizing activity of vitamin C against M. tuberculosis in vitro was not observed in mice, we believe this activity needs further investigation. Comparison of vitamin C treated Mycobacterium tuberculosis transcriptome relative to untreated; Three biological replicates, second is a dye flip
2013-05-24 | E-GEOD-42293 | biostudies-arrayexpress
Project description:While persistence in a dormant state is crucial for the life cycle of Mycobacterium tuberculosis, no investigation regarding dormancy survival of different strains across different lineages was performed so far. We analyzed responses to oxygen starvation and recovery in terms of growth, metabolism and transcription. All different strains belonging to the (Euro-American) lineage (L4) showed similar survival and resuscitation characteristics. Different clinical isolates from the Beijing (L2) , East African-Indian (L3), and Delhi/Central Asian (L1) did not survive oxygen starvation. We show that dormancy survival is lineage-dependent. Recovery from O2 starvation was observed in Euro-American (L4) but no other used strains (L1, L2, L3). Thus, resuscitation from dormancy after oxygen starvation is not a general feature of all M. tuberculosis strains as thought before. Our findings are of key importance to understand infection dynamics of non-Euro American vs Euro American strains and to develop drugs targeting the dormant state.
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Project description:While persistence in a dormant state is crucial for the life cycle of Mycobacterium tuberculosis, no investigation regarding dormancy survival of different strains across different lineages was performed so far. We analyzed responses to oxygen starvation and recovery in terms of growth, metabolism and transcription. All different strains belonging to the (Euro-American) lineage (L4) showed similar survival and resuscitation characteristics. Different clinical isolates from the Beijing (L2) , East African-Indian (L3), and Delhi/Central Asian (L1) did not survive oxygen starvation. We show that dormancy survival is lineage-dependent. Recovery from O2 starvation was observed in Euro-American (L4) but no other used strains (L1, L2, L3). Thus, resuscitation from dormancy after oxygen starvation is not a general feature of all M. tuberculosis strains as thought before. Our findings are of key importance to understand infection dynamics of non-Euro American vs Euro American strains and to develop drugs targeting the dormant state.
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