Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the effects of oxidant stress on the catalase activity and hydrogen peroxide sensitivity of Neisseria gonorrhoeae. N. gonorrhoeae is an obligate pathogen of man that evokes a remarkable but ineffective neutrophil response. Gonococci make no superoxide dismutase but express high catalase activity. Gonococcal catalase activity increased threefold when organisms were subjected to 1.0 mM hydrogen peroxide. This increase in catalase activity was marked by a parallel increase in protein concentration recognized by a rabbit polyclonal antibody raised against the purified gonococcal enzyme. Catalase was primarily localized to the gonococcal cytoplasm in the presence or absence of stress; only a single isoenzyme of catalase could be identified. Exposure of gonococci to neutrophil-derived oxidants was accomplished by stimulating neutrophils with phorbol myristate acetate or by using gonococcal Opa variants that interacted with neutrophils with different degrees of efficiency. Gonococci exposed to neutrophils demonstrated a twofold increase in catalase activity in spite of some reduction in viability. Exposure of gonococci to 1.0 mM hydrogen peroxide made the organisms significantly more resistant to higher concentrations of hydrogen peroxide and to neutrophils than control organisms. These results suggest that catalase is an important defense for N. gonorrhoeae during attack by human neutrophils. The rapid response of this enzyme to hydrogen peroxide should be taken into consideration in studies designed to evaluate the interaction between neutrophils and gonococci.
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PMID:Regulation of catalase in Neisseria gonorrhoeae. Effects of oxidant stress and exposure to human neutrophils. 152 9

Catalase, which catalyzes the reduction of hydrogen peroxide to oxygen and water, is considered the primary defense of Neisseria gonorrhoeae against exogenous hydrogen peroxide. Recent reports have demonstrated drastically different sensitivities of the organism to hydrogen peroxide ranging from greater than 80% survival after challenge with 30 mM hydrogen peroxide to less than 0.001% survival after challenge with 10 mM hydrogen peroxide. In this study, we have examined the hydrogen peroxide sensitivities of six clinical gonococcal isolates. The study demonstrates that the variations in gonococcal hydrogen peroxide sensitivities previously reported can be attributed to (i) differences in experimental methods employed or (ii) variation among different gonococcal strains. All of the gonococcal isolates examined generated similar concentrations of catalase, implying that the differences in the H2O2 sensitivity observed may depend on factors in addition to catalase.
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PMID:Variation in hydrogen peroxide sensitivity between different strains of Neisseria gonorrhoeae is dependent on factors in addition to catalase activity. 816 86

A study of 4718 women 15-49 years old in southwestern Uganda's Rakai district suggests that the loss of lactobacilli and the presence of bacterial vaginosis may increase susceptibility to HIV-1. These women were part of an ongoing community-based trial of sexually transmitted disease (STD) control as a strategy for AIDS prevention. The rate of HIV-1 infection among these women was 19.5%. Moderate bacterial vaginosis was detected in 44.5% of women, while 6.4% had severe bacterial vaginosis. STD rates were 10.2% for active or recent syphilis, 22.4% for trichomonas, 2.4% for gonorrhea, and 3.6% for chlamydia. The HIV rate was lowest (14.2%) among women with normal bacterial flora and highest (26.7%) among those with severe bacterial vaginosis. The HIV-abnormal flora association was higher in younger women, for whom HIV acquisition is likely to be recent, than in older women. In multiple logistic regression analyses adjusted for age, number of sexual partners, trichomonas, and syphilis, the odds ratio (OR) for HIV-1 infection associated with any abnormal vaginal flora was 1.52 (95% confidence interval [CI], 1.22-1.90) and with all bacterial vaginosis was 1.56 (95% CI, 1.24-1.97). These adjusted ORs were 1.50 (95% CI, 1.18-1.89) for moderate and 2.08 (95% CI, 1.48-2.94) for severe bacterial vaginosis. A cross-sectional study cannot ascertain whether the abnormalities in vaginal flora occurred before or after HIV seroconversion. However, the significantly increased proportion of HIV-infected women with depleted or absent vaginal lactobacilli is consistent with in vitro studies showing that hydrogen peroxidase-producing lactobacilli in vaginal flora inhibit HIV-1 viral replication. If the ongoing prospective study suggests a causal association with HIV, treatment of abnormal flora or bacterial vaginosis with inexpensive, effective drugs such as metronidazole may be indicated.
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PMID:HIV-1 infection associated with abnormal vaginal flora morphology and bacterial vaginosis. 965 90

Catalase is hypothesized to be critical in the protection of Neisseria gonorrhoeae from H2O2 produced during aerobic respiration and by phagocytes during infection. Here we cloned the catalase (kat) gene of gonococcal strain FA1090 and constructed a genetically defined N. gonorrhoeae kat mutant to assess the role of catalase in defense against oxidative stress. The gonococcal kat gene conferred increased H2O2 resistance to a catalase-deficient Escherichia coli strain. Mutation of the kat gene in strain FA1090 via an in-frame deletion resulted in increased sensitivity to H2O2 and paraquat, an inducer of toxic oxygen radicals. Expression of catalase in trans from a shuttle vector restored catalase activity and paraquat resistance to the kat mutant, but not resistance to H2O2. The inability to fully complement the mutant was perhaps due to a modification in the catalase, as evidenced by altered mobility of the recombinant catalase on activity gels when expressed from the shuttle vector in N. gonorrhoeae. Additionally, we showed a 262 base pair region upstream of the kat gene is required for expression in E. coli and a putative fumarate-nitrate regulator (FNR) binding site is located in this region.
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PMID:A Neisseria gonorrhoeae catalase mutant is more sensitive to hydrogen peroxide and paraquat, an inducer of toxic oxygen radicals. 1531 45