Stress Responses in Mycobacteria

Gupta, Surbhi; Chatterji, Dipankar

doi:10.1080/15216540500090611

Cited by 53 publications

(43 citation statements)

References 60 publications

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“…Attack at a sugar leads to sugar fragmentation as well as loss of base resulting in strand break. Radicals can also damage the bases of the DNA such as ring-saturated thymines, hydroxyl methyl uracil, thymine fragments and adenine ring opened products [15,16]. The results in this study showed that upon increasing oxidative and pH values more clump formation was detected.…”

Section: Resistence Tosupporting

confidence: 59%

Effect of Environmental Stresses on Growth Pattern, Biofilm Formation and Biochemical Characteristics of Mycobacterium marinum CCUG20998

Ghasemi

Moslem

Mirpour

2016

Zahedan J Res Med Sci

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Background: Mycobacterium marinum is a ubiquitous, slow-growing nontuberclosis Mycobacterium (NTM), it can causes disseminated granulomatous infections in fish. Outbreaks in fisheries can be financially devastating and can also increase the chance of human exposure. Objectives: The aim of this work was evaluating the effects of some environmental stresses on M. marinum CCUG 20998. Methods: In this descriptive-analytic study M. marinum CCUG 20998 was subjected to different conditions of environmental stresses such as pH, oxidative, osmotic pressure, and temperatures. The effects of stresses were studied on growth, biofilm formation, and cell division and biochemical characteristics of M. marinum CCUG 20998.The growth data were analyzed by measuring colony forming unit (CFU) using SPSS software version 19. Results:The results showed that sodium chloride and hydrogen peroxide at %10 and 9600 ppm concentrations inhibit. Marinum CCUG 20998 growths, respectively. Tolerance to pH = 11 and temperature at 82.5°C was detectable. Also, environmental stresses could affects on some biochemical characteristics of M. marinum CCUG 20998. Biofilm formation reduced upon using all stress conditions. Conclusions: Bacteria are able to adapt to dramatically different environments, In the case of mycobacteria, there is direct correlation between stress and pathogenicity. The results obtained from this study provided useful information on survival and tolerance of M. marinum CCUG 20998 to different environmental conditions. Survival under stress conditions might not reflect the in vivo situation where host factors also contribute to establishment of the organism during infection.

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Section: Resistence Tosupporting

confidence: 59%

Effect of Environmental Stresses on Growth Pattern, Biofilm Formation and Biochemical Characteristics of Mycobacterium marinum CCUG20998

Ghasemi

Moslem

Mirpour

2016

Zahedan J Res Med Sci

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“…Although free radical production has been shown to have minimal effects on the survival of M. tuberculosis, there are little data on the effects of superoxide and nitric oxide production on M. abscessus viability (8,25). We found that THP-1 cells produced little superoxide in response to the phagocytosed M abscessus.…”

Section: Discussionmentioning

confidence: 71%

“…It has been shown that another mycobacterium species, M. tuberculosis, can withstand oxidative environments inside macrophages by up-regulating redox-sensing proteins (8). M. tuberculosis is somewhat susceptible to nitric oxide production; when nitric oxide production is blocked, certain strains of M. tuberculosis displayed enhanced intracellular growth (25).…”

Section: Mnte-2-pyp Does Not Reduce Intracellular Growth Of M Abscesmentioning

confidence: 99%

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The Antioxidant Mimetic, MnTE-2-PyP, Reduces Intracellular Growth of Mycobacterium abscessus

Oberley‐Deegan

Lee

Morey

et al. 2009

Am J Respir Cell Mol Biol

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Mycobacterium abscessus is a rapidly growing environmental mycobacterium that can cause severe skin, soft tissue, and lung infections. M. abscessus grows inside macrophages, and these cells release a vast number of proinflammatory cytokines in response to infections. The metalloporphyrin, MnTE-2-PyP, is a broad antioxidant that reduces inflammatory cell signaling. Macrophage-like THP-1 cells were infected with M. abscessus in the presence or absence of MnTE-2-PyP. MnTE-2-PyP significantly decreased, in a dose-dependent manner, the number of M. abscessus organisms recovered from infected THP-1 cells 4 and 8 days after infection. Furthermore, when combined with clarithromycin, MnTE-2-PyP additively reduced the number of cells associated with M. abscessus. A mechanism of bacterial growth inhibition by MnTE-2-PyP was then elucidated. It was found that MnTE-2-PyP promoted the survival of infected THP-1 cells and increased fusion of M. abscessus-containing phagosomes with lysosomes.

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“…This consensus for SigF-dependent promoters in M. smegmatis was identified as GTTT-N (15)(16)(17) -GGGTA ( Fig. 2C).…”

Section: Resultsmentioning

confidence: 99%

The SigF Regulon in Mycobacterium smegmatis Reveals Roles in Adaptation to Stationary Phase, Heat, and Oxidative Stress

et al. 2010

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SigF is an alternative sigma factor that is highly conserved among species of the genus Mycobacterium. In this study we identified the SigF regulon in Mycobacterium smegmatis using whole-genome microarray and promoter consensus analyses. In total, 64 genes in exponential phase and 124 genes in stationary phase are SigF dependent (P < 0.01, >2-fold expression change). Our experimental data reveal the SigF-dependent promoter consensus GTTT-N (15-17) -GGGTA for M. smegmatis, and we propose 130 potential genes under direct control of SigF, of which more than 50% exhibited reduced expression in a ⌬sigF strain. We previously reported an increased susceptibility of the ⌬sigF strain to heat and oxidative stress, and our expression data indicate a molecular basis for these phenotypes. We observed SigF-dependent expression of several genes purportedly involved in oxidative stress defense, namely, a heme-containing catalase, a manganese-containing catalase, a superoxide dismutase, the starvation-induced DNA-protecting protein MsDps1, and the biosynthesis genes for the carotenoid isorenieratene. Our data suggest that SigF regulates the biosynthesis of the thermoprotectant trehalose, as well as an uptake system for osmoregulatory compounds, and this may explain the increased heat susceptibility of the ⌬sigF strain. We identified the regulatory proteins SigH3, PhoP, WhiB1, and WhiB4 as possible genes under direct control of SigF and propose four novel anti-sigma factor antagonists that could be involved in the posttranslational regulation of SigF in M. smegmatis. This study emphasizes the importance of this sigma factor for stationary-phase adaptation and stress response in mycobacteria.The success of Mycobacterium tuberculosis as a pathogen can be attributed to its capacity to adapt to environmental changes throughout the course of infection. These changes include nutrient deprivation, hypoxia, various exogenous stress conditions, and the intraphagosomal environment. A large cohort of genes that facilitate this adaptation has been identified, and among them are many genes for transcriptional regulators such as sigma factors that modulate gene expression in response to different physiological cues. Sigma factors interact with the RNA polymerase to allow binding to specific promoter sequences and initiation of gene transcription. Mycobacteria harbor sigma factors of only the 70 family, which fall into four different categories. SigA (group 1) is the essential primary sigma factor in mycobacteria, and SigB (group 2) is its nonessential paralog. SigF (group 3) and extracytoplasmic function (ECF) sigma factors (group 4) are alternative sigma factors, which allow adaptation to a wide range of internal and external stimuli. Alternative sigma factors vary considerably in type and numbers between species, mirroring their different requirements for stress response (15).Thirteen sigma factors have been identified in M. tuberculosis (23,29). Eleven of these are classified as alternative sigma factors, and many of them are recognized as ...

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Stress Responses in Mycobacteria

Cited by 53 publications

References 60 publications

Effect of Environmental Stresses on Growth Pattern, Biofilm Formation and Biochemical Characteristics of Mycobacterium marinum CCUG20998

Effect of Environmental Stresses on Growth Pattern, Biofilm Formation and Biochemical Characteristics of Mycobacterium marinum CCUG20998

The Antioxidant Mimetic, MnTE-2-PyP, Reduces Intracellular Growth of Mycobacterium abscessus

The SigF Regulon in Mycobacterium smegmatis Reveals Roles in Adaptation to Stationary Phase, Heat, and Oxidative Stress

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