Oxidative Stress Response and Characterization of theoxyR-ahpCandfurA-katGLoci inMycobacterium marinum

Pagán-Ramos, Eileen; Song, Jian; McFalone, M.; Mudd, Michal H.; Deretić, Vojo

doi:10.1128/jb.180.18.4856-4864.1998

Cited by 80 publications

(42 citation statements)

References 53 publications

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“…However, some studies showed that the susceptibility to H 2 O 2 was not determined by katG gene [5,15]. For example, Western blotting analysis demonstrated that the AhpC protein of Mycobacterium marinum was increased after H 2 O 2 treatment [25] which appeared to be independent from the katG mediated H 2 O 2 resistance [25]. More importantly, the Southern Indian [7] and our Western mutant (sigJ knockout) strains of M. tuberculosis contain KatG but are sensitive to killing by H 2 O 2 [5,7].…”

Section: Discussionmentioning

confidence: 99%

The gene controls sensitivity of the bacterium to hydrogen peroxide

Hu¹,

Kendall²,

Stoker³

et al. 2004

FEMS Microbiology Letters

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Sigma factors are important global regulators which control bacterial gene expression during growth and in response to stress. Previous work showed that mRNA of the sigJ gene was up-regulated in late stationary-phase and after rifampicin treatment. In order to verify the function of SigJ, we constructed a Mycobacterium tuberculosis mutant lacking the sigJ gene. In a microaerophilic stationary-phase model, the sigJ mutant showed the same growth pattern as the wild-type strain. In an immune stasis murine model in which the bacterial number plateaued between the second and the 15th week, the mutant showed a similar growth curve to the wild-type strain. However, the sigJ mutant was more susceptible to killing by H2O2 than its parental strain. The parental level of sensitivity to H2O2 was recovered in the sigJ complemented strain. These data suggest that the SigJ protein is not essential for survival in long-term stationary phase or in bacterial stasis in mice. However, the sigJ gene may control an alternative H2O2 resistance pathway.

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Section: Discussionmentioning

confidence: 99%

The gene controls sensitivity of the bacterium to hydrogen peroxide

Hu¹,

Kendall²,

Stoker³

et al. 2004

FEMS Microbiology Letters

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“…The katG encodes a Catalase-Peroxidase which is important for the virulence of M. tuberculosis (36). The katG locus is genetically linked to furA, which encodes a homolog of the ferric uptake regulator (37). Among all the mycobacterial species studied, the DNA region immediately upstream of the katG genes is highly conserved and encodes furA, suggesting a putative involvement of the FurA protein in katG regulation.…”

Section: Antioxidant Defense In Mycobacteriamentioning

confidence: 99%

Stress Responses in Mycobacteria

Gupta

Chatterji

2005

IUBMB Life (International Union of Biochemistry and Molecular B

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SummaryMycobacterium tuberculosis is a successful pathogen that overcomes numerous challenges presented by the immune system of the host. This bacterium usually establishes a chronic infection in the host where it may silently persist inside a granuloma until, a failure in host defenses, leads to manifestation of the disease. None of the conventional anti-tuberculosis drugs are able to target these persisting bacilli. Development of drugs against such persisting bacilli is a constant challenge since the physiology of these dormant bacteria is still not understood at the molecular level. Some evidence suggests that the in vivo environment encountered by the persisting bacteria is anoxic and nutritionally starved. Based on these assumptions, anaerobic and starved cultures are used as models to study the molecular basis of dormancy. This review outlines the problem of persistence of M. tuberculosis and the various in vitro models used to study mycobacterial latency. The basis of selecting the nutritional starvation model has been outlined here. Also, the choice of M. smegmatis as a model suitable for studying mycobacterial latency is discussed. Lastly, general issues related to oxidative stress and bacterial responses to it have been elaborated. We have also discussed general control of OxyR-mediated regulation and emphasized the processes which manifest in the absence of functional OxyR in the bacteria. Lastly, a new class of protein called Dps has been reviewed for its important role in protecting DNA under stress. IUBMB Life, 57: 149 -159, 2005

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“…The fur-like genes have also been reported to be catalase-peroxidase regulators in Streptomyces (Zou et al, 1999;Hahn et al, 2000). In some Mycobacterium species that are naturally mutated at OxyR, fur homologue has been proved as the regulator of the katG gene encoding catalase-peroxidase for the response to oxidative stress (Pagan-Ramos et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…The primary role for catalases is to protect cells against the damage caused by reactive oxygen species to cellular components, including nucleic acids, proteins and cell membranes (Imlay and Linn, 1988;Storz and Imlay, 1999). Catalases have been implicated to be important for the survival of some pathogenic bacteria during infection (Loprasert et al, 1996;Laochumroonvorapong et al, 1997;Pagan-Ramos et al, 1998) and even for the life span of a multicellular organism (Melov et al, 2000). The catalases present in different bacteria are diverse in protein structures, cofactor requirements and gene regulations (Bravo et al, 1997;Loewen, 1997).…”

Section: Introductionmentioning

confidence: 99%

Feedback regulation of an Agrobacterium catalase gene katA involved in Agrobacterium–plant interaction

Pan

2001

Molecular Microbiology

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Catalases are known to detoxify H2O2, a major component of oxidative stress imposed on a cell. An Agrobacterium tumefaciens catalase encoded by a chromosomal gene katA has been implicated as an important virulence factor as it is involved in detoxification of H2O2 released during Agrobacterium–plant interaction. In this paper, we report a feedback regulation pathway that controls the expression of katA in A. tumefaciens cells. We observed that katA could be induced by plant tissue sections and by acidic pH on a minimal medium, which resembles the plant environment that the bacteria encounter during the course of infection. This represents a new regulatory factor for catalase induction in bacteria. More importantly, a feedback regulation was observed when the katA–gfp expression was studied in different genetic backgrounds. We found that introduction of a wild‐type katA gene encoding a functional catalase into A. tumefaciens cells could repress the katA–gfp expression over 60‐fold. The katA gene could be induced by H2O2 and the encoded catalase could detoxify H2O2. In addition, the katA‐gfp expression of one bacterial cell could be repressed by other surrounding catalase‐proficient bacterial cells. Furthermore, mutation at katA caused a 10‐fold increase of the intracellular H2O2 concentration in the bacteria grown on an acidic pH medium. These results suggest that the endogenous H2O2 generated during A. tumefaciens cell growth could serve as the intracellular and intercellular inducer for the katA gene expression and that the acidic pH could pose an oxidative stress on the bacteria. Surprisingly, one mutated KatA protein, exhibiting no significant catalase activity as a result of the alteration of two important residues at the putative active site, could partially repress the katA–gfp expression. The feedback regulation of the katA gene by both catalase activity and KatA protein could presumably maintain an appropriated level of catalase activity and H2O2 inside A. tumefaciens cells.

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Oxidative Stress Response and Characterization of theoxyR-ahpCandfurA-katGLoci inMycobacterium marinum

Cited by 80 publications

References 53 publications

The gene controls sensitivity of the bacterium to hydrogen peroxide

The gene controls sensitivity of the bacterium to hydrogen peroxide

Stress Responses in Mycobacteria

Feedback regulation of an Agrobacterium catalase gene katA involved in Agrobacterium–plant interaction

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