scholarly journals Proteome Profiling of Mycobacterium tuberculosis Cells Exposed to Nitrosative Stress

ACS Omega ◽  
2022 ◽  
Author(s):  
Alemayehu Godana Birhanu ◽  
Marta Gómez-Muñoz ◽  
Shewit Kalayou ◽  
Tahira Riaz ◽  
Timo Lutter ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nitrosative Stress ◽  
Proteome Profiling

scholarly journals Cytosolic Proteome Profiling of Aminoglycosides Resistant Mycobacterium tuberculosis Clinical Isolates Using MALDI-TOF/MS

2016 ◽  
Vol 7 ◽  
Author(s):  
Divakar Sharma ◽  
Manju Lata ◽  
Rananjay Singh ◽  
Nirmala Deo ◽  
Krishnamurthy Venkatesan ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Isolates ◽  
Maldi Tof Ms ◽  
Proteome Profiling ◽  
Maldi Tof ◽  
Tof Ms

scholarly journals DNA Alkylation Damage as a Sensor of Nitrosative Stress in Mycobacterium tuberculosis

2003 ◽  
Vol 71 (2) ◽  
pp. 997-1000 ◽  
Author(s):  
Steven I. Durbach ◽  
Burkhard Springer ◽  
Edith E. Machowski ◽  
Robert J. North ◽  
K. G. Papavinasasundaram ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mycobacterium Tuberculosis ◽  
Nitrosative Stress ◽  
Dna Alkylation ◽  
Genotoxic Effects ◽  
Alkylation Damage ◽  
Damage Repair

ABSTRACT One of the cellular consequences of nitrosative stress is alkylation damage to DNA. To assess whether nitrosative stress is registered on the genome of Mycobacterium tuberculosis, mutants lacking an alkylation damage repair and reversal operon were constructed. Although hypersensitive to the genotoxic effects of N-methyl-N′-nitro-N-nitrosoguanidine in vitro, the mutants displayed no phenotype in vivo, suggesting that permeation of nitrosative stress to the level of cytotoxic DNA damage is restricted.

scholarly journals Dihydrolipoamide Acyltransferase Is Critical for Mycobacterium tuberculosis Pathogenesis

2006 ◽  
Vol 74 (1) ◽  
pp. 56-63 ◽  
Author(s):  
Shuangping Shi ◽  
Sabine Ehrt
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Sodium Nitrite ◽  
Pyruvate Dehydrogenase ◽  
Nitrosative Stress ◽  
Oxidative And Nitrosative Stress ◽  
Retarded Growth ◽  
Mouse Macrophages

ABSTRACT Mycobacterium tuberculosis has evolved to persist in host macrophages, where it faces a nutrient-poor environment and is exposed to oxidative and nitrosative stress. To defend itself against oxidative/nitrosative stress, M. tuberculosis expresses an NADH-dependent peroxidase and peroxynitrite reductase that is encoded by ahpC, ahpD, lpd, and dlaT. In addition to its central role in the peroxynitrite reductase complex, dlaT (Rv2215) also encodes the E2 component of pyruvate dehydrogenase. Here we demonstrate that inactivation of dlaT in the chromosome of H37Rv resulted in a mutant (H37RvΔdlaT) that displayed phenotypes associated with DlaT's role in metabolism and in defense against nitrosative stress. The H37RvΔdlaT strain showed retarded growth in vitro and was highly susceptible to killing by acidified sodium nitrite. Mouse macrophages readily killed intracellular H37RvΔdlaT organisms, and in mice dlaT was required for full virulence.

scholarly journals Silencing of Oxidative Stress Response in Mycobacterium tuberculosis: Expression Patterns of ahpC in Virulent and Avirulent Strains and Effect ofahpC Inactivation

2001 ◽  
Vol 69 (10) ◽  
pp. 5967-5973 ◽  
Author(s):  
B. Springer ◽  
S. Master ◽  
P. Sander ◽  
T. Zahrt ◽  
M. McFalone ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Nitrosative Stress ◽  
Expression Patterns ◽  
Acute Infection ◽  
Cumene Hydroperoxide ◽  
Green Fluorescence Protein ◽  
Normal Growth ◽  
Oxidative And Nitrosative Stress ◽  
Virulent Strains

ABSTRACT Intracellular pathogens such as Mycobacterium tuberculosis are able to survive in the face of antimicrobial products generated by the host cell in response to infection. The product of the alkyl hydroperoxide reductase gene (ahpC) of M. tuberculosis is thought to be involved in protecting the organism against both oxidative and nitrosative stress encountered within the infected macrophage. Here we report that, contrary to expectations, ahpC expression in virulent strains of M. tuberculosis and Mycobacterium bovis grown in vitro is repressed, often below the level of detection, whereas expression in the avirulent vaccine strainM. bovis BCG is constitutively high. The repression of the ahpC gene of the virulent strains is independent of the naturally occurring lesions of central regulatoroxyR. Using a green fluorescence protein vector (gfp)-ahpC reporter construct we present data showing that repression of ahpC of virulentM. tuberculosis also occurred during growth inside macrophages, whereas derepression in BCG was again seen under identical conditions. Inactivation of ahpC on the chromosome ofM. tuberculosis by homologous recombination had no effect on its growth during acute infection in mice and did not affect in vitro sensitivity to H2O2. However, consistent with AhpC function in detoxifying organic peroxides, sensitivity to cumene hydroperoxide exposure was increased in theahpC::Kmr mutant strain. The preservation of a functional ahpC gene in M. tuberculosis in spite of its repression under normal growth conditions suggests that, while AhpC does not play a significant role in establishing infection, it is likely to be important under certain, as yet undefined conditions. This is supported by the observation that repression of ahpC expression in vitro was lifted under conditions of static growth.

scholarly journals Dissecting the RecA-(In)dependent Response to Mitomycin C in Mycobacterium tuberculosis Using Transcriptional Profiling and Proteomics Analyses

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1168
Author(s):  
Anna Brzostek ◽  
Przemysław Płociński ◽  
Alina Minias ◽  
Aneta Ciszewska ◽  
Filip Gąsior ◽  
...  
Keyword(s):  
Dna Damage ◽  
Mycobacterium Tuberculosis ◽  
Mitomycin C ◽  
Nitrosative Stress ◽  
Transcriptional Profiling ◽  
Regulatory System ◽  
Transcript Level ◽  
Reca Gene ◽  
Oxidative And Nitrosative Stress ◽  
Genes Encoding

Mycobacteria exploit at least two independent global systems in response to DNA damage: the LexA/RecA-dependent SOS response and the PafBC-regulated pathway. Intracellular pathogens, such as Mycobacterium tuberculosis, are exposed to oxidative and nitrosative stress during the course of infection while residing inside host macrophages. The current understanding of RecA-independent responses to DNA damage is based on the saprophytic model of Mycobacterium smegmatis, a free-living and nonpathogenic mycobacterium. The aim of the present study was to identify elements of RecA-independent responses to DNA damage in pathogenic intracellular mycobacteria. With the help of global transcriptional profiling, we were able to dissect RecA-dependent and RecA-independent pathways. We profiled the DNA damage responses of an M. tuberculosis strain lacking the recA gene, a strain with an undetectable level of the PafBC regulatory system, and a strain with both systems tuned down simultaneously. RNA-Seq profiling was correlated with the evaluation of cell survival in response to DNA damage to estimate the relevance of each system to the overall sensitivity to genotoxic agents. We also carried out whole-cell proteomics analysis of the M. tuberculosis strains in response to mitomycin C. This approach highlighted that LexA, a well-defined key element of the SOS system, is proteolytically inactivated during RecA-dependent DNA repair, which we found to be transcriptionally repressed in response to DNA-damaging agents in the absence of RecA. Proteomics profiling revealed that AlkB was significantly overproduced in the ΔrecA pafBCCRISPRi/dCas9 strain and that Holliday junction resolvase RuvX was a DNA damage response factor that was significantly upregulated regardless of the presence of functional RecA and PafBC systems, thus falling into a third category of DNA damage factors: RecA- and PafBC-independent. While invisible to the mass spectrometer, the genes encoding alkA, dnaB, and dnaE2 were significantly overexpressed in the ΔrecA pafBCCRISPRi/dCas9 strain at the transcript level.

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