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PubMed1995

Effect of ethanol, propanol, butanol, and catalase enzyme blockers on beta-endorphin secretion from primary cultures of hypothalamic neurons: evidence for a mediatory role of acetaldehyde in ethanol stimulation of beta-endorphin release.

Previously, we have shown that low doses of ethanol (12.5-100 mM) and acetaldehyde (12.5-50 microM), but not salsolinol, enhanced immunoreactive beta-endorphin (IR-beta-EP) secretion from fetal hypothalamic neurons in primary culture. In this study, the effects of ethanol, propanol, and butanol, as well as the effect of catalase inhibitors on IR-beta-EP secretion were studied in vitro to determine the role of membrane fluidization and ethanol metabolism on ethanol-induced IR-beta-EP secretion. The primary cultures of fetal hypothalamic neurons were maintained for 8-9 days in chemically defined medium and treated for 5 hr with ethanol (50 mM), propanol (25 and 50 mM), and butanol (25 and 50 mM). Determination of hourly secretion of IR-beta-EP from the cultures revealed that only 50 mM ethanol caused stimulation of IR-beta-EP secretion, whereas propanol and butanol did not alter IR-beta-EP response at any given concentration. Pretreatment of these cultures with the catalase inhibitors, 3-amino-1,2,4-triazole (3-AT; 1, 5, and 10 mM), caused a dose-dependent inhibition of ethanol-stimulated IR-beta-EP secretion, but did not inhibit dibutyryl cAMP (dcAMP)-stimulated IR-beta-EP secretion. Another catalase inhibitor, sodium azide (5 mM), also inhibited ethanol-stimulated IR-beta-EP secretion. Measurement of acetaldehyde production in cultured cells and media after ethanol or dcAMP treatments revealed that cultured cells produce acetaldehyde only after ethanol treatment and at levels of acetaldehyde (8-24 microM) that are known to evoke IR-beta-EP release. The catalase inhibitor 3-AT (10 mM) treatment reduced ethanol-evoked acetaldehyde production.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Butanol↗
PubMedDate not supplied

Catalase is the bacteria-derived detoxifying substance against paramecia-killing toxin in wheat grass powder infusion.

Paramecium cells are usually cultured in a wheat grass powder infusion inoculated with Klebsiella pneumoniae. However, non-bacterized wheat grass powder infusion is toxic to paramecia, and bacteria-derived substance detoxifies the toxic substance. Here, the detoxifying substance from K. pneumoniae, which was found to be proteinaceous, was purified to homogeneity. The protein had an apparent molecular mass of about 200 kDa by gel filtration and 92 kDa by SDS-polyacrylamide gel electrophoresis. Although the amino acid sequence of the amino terminal region did not show a high sequence homology with any reported proteins, amino acid sequences of internal regions of the protein were nearly identical to catalase HPII from Escherichia coli. When the wheat grass powder infusion was treated at 25 degrees C for 1 h with commercially available catalase from bovine liver, the toxicity of the infusion against paramecia was completely abolished. The initial concentration of hydrogen peroxide in the wheat grass powder infusion was about 30 microM and was completely decomposed by the catalase treatment. Therefore, the toxic substance in the wheat grass powder infusion and the detoxifying substance from K. pneumoniae are considered as hydrogen peroxide and catalase, respectively.

Amino Acid Sequence↗
PubMed1976

Factors affecting catalase level and sensitivity to hydrogen peroxide in Escherichia coli.

Composition of the culture medium, growth phase, and temperature play important roles in the sensitivity of Escherichia coli to H2O2. The medium and growth phase affected the sensitivity of the cells to H2O2 by modifying the amount of catalase synthesized by them, whereas the effect of temperature was due to the thermolability of the enzyme. Since catalase is unstable in the presence of its substrate, the correlation between the catalase level in the cells and their sensitivity to H2O2 could be observed only when the H2O2 concentration was not excessive in proportion to the amount of catalase.

Catalase↗
PubMed1976

Catalase: its effect on microbial enumeration.

The addition of catalase to the surface of selective medium plates permitted increased enumeration of physically or chemically injured (stressed) microorganisms. Catalase acted by preventing the accumulation of hydrogen peroxide in, or around, injured cells. Heat-injured Staphylococcus aureus cells had decreased catalase activity, and heat-inactivated catalase had no effect on enumeration.

Bacteria↗
PubMed1979

Catalase activity during the recovery of heat-stressed Staphylococcus aureus MF-31.

Sublethal heating of Staphylococcus aureus produced little loss of catalase activity, but incubation of the injured cells in tryptic soy broth, with or without 10% NaCl added, produced an 85% decrease in catalase activity. Cells recovered in tryptic soy broth demonstrated increases in catalase levels after approximately 5 h, whereas in tryptic soy broth with 10% NaCl the levels remained low for at least 12 h. Thus, the loss of catalase activity during the recovery period was greater than during the heat treatment.

Catalase↗
PubMed1987

Synthesis of catalase in Staphylococcus aureus MF-31.

During the growth of Staphylococcus aureus MF-31, initial catalase activity dropped to a reduced level at the onset of exponential phase before increasing. When S. aureus was grown at 25, 32, or 37 degrees C, catalase activity was found to decrease by 80 to 90% within 1 h of inoculation. Two catalase-negative mutants and wild-type S. aureus MF-31 cells were exposed to exogenous 20 mM H2O2 for 15 min. For wild-type S. aureus, there was no effect from H2O2 until min 15, at which time a 10% decrease in CFU was observed. Both mutants showed increased sensitivity to the H2O2, with 56 and 71% reductions in the CFU for mutants C3 and C4, respectively, after a 15-min exposure. Cells of mutant and wild-type S. aureus were subjected to sublethal heating at 52 degrees C for 20 min. The lack of catalase activity in the mutants resulted in large decreases in enumeration.

Catalase↗
PubMed2001

Characterization of a heme-dependent catalase from Methanobrevibacter arboriphilus.

Recently it was reported that methanogens of the genus Methanobrevibacter exhibit catalase activity. This was surprising, since Methanobrevibacter species belong to the order Methanobacteriales, which are known not to contain cytochromes and to lack the ability to synthesize heme. We report here that Methanobrevibacter arboriphilus strains AZ and DH1 contained catalase activity only when the growth medium was supplemented with hemin. The heme catalase was purified and characterized, and the encoding gene was cloned. The amino acid sequence of the catalase from the methanogens is most similar to that of Methanosarcina barkeri.

Amino Acid Sequence↗
PubMed1981

Distribution of superoxide dismutase, catalase, and peroxidase activities among Treponema pallidum and other spirochetes.

Representative members of Spirochaetales were surveyed for their content of superoxide dismutase (SOD), catalase, and peroxidase activities. Only Leptospira exhibited peroxidase activity. Obligately anaerobic cultivable Treponema and Spirochaeta possessed no SOD or peroxidative capabilities. Upon polyacrylamide gel electrophoresis, Spirochaeta aurantia, Borrelia hermsi, and five Leptospira biflexa serovars showed SOD activity associated with one electrophoretic band which was inhibited by H2O2, suggesting that they were iron-containing dismutases. These spirochetes could be distinguished by differences in relative mobilities of their SODs. SOD activity, but not catalase activity, was induced aerobically in S. aurantia. All Leptospira interrogans serovars and two L. biflexa serovars lacked significant SOD activity. These SOD-deficient strains of Leptospira, with one exception, possessed high levels of catalase activity. The Nichols strain of virulent Treponema pallidum possessed SOD and catalase activities, but lacked peroxidase activity. The SOD in T. pallidum exhibited two electrophoretic bands containing copper and zinc, and its relative mobility was identical to that of purified rabbit SOD. Immunization of sheep with purified rabbit SOD resulted in antiserum which inhibited both rabbit SOD and T. pallidum SOD assayed by spectrophotometric analysis or activity staining following polyacrylamide gel electrophoresis. In agarose gel diffusion, precipitin lines of identity were observed between purified rabbit SOD and cell extracts of T. pallidum. These data indicated that the SOD activity detected in T. pallidum was host derived.

Borrelia↗
PubMed1983

Studies on the catalase of Histoplasma capsulatum.

Factors which control the levels of catalase within yeast cells of Histoplasma capsulatum were studied. Only a small fraction of the total catalase activity could be detected in whole cells. The bulk of the activity was revealed in cell-free extracts or in cells permeabilized with acetone. The formation of the enzyme was regulated by glucose and by oxygen. There were large, consistent differences in the levels of catalase among strains of H. capsulatum. The sensitivity of the strains to H2O2 toxicity also varied remarkably. Peroxidase activity could not be detected in cell-free extracts of the strains. Resistance to H2O2 did not correspond to levels of catalase. There was no obvious correlation of H2O2 sensitivity and virulence among the strains.

Catalase↗
PubMed1989

Loss of catalase activity in Tn1545-induced mutants does not reduce growth of Listeria monocytogenes in vivo.

Two catalase-negative mutants of Listeria monocytogenes were obtained by chromosomal insertions of the conjugative transposon Tn1545. The loss of catalase activity did not reduce the level of virulence of these mutants in mice. Indeed, both mutants were capable of growing in host tissues at the same rate as the parental catalase-positive strain. These results favor the view that catalase does not play a critical role in the resistance of L. monocytogenes to macrophage killing.

Animals↗
PubMed1994

Characterization and virulence analysis of catalase mutants of Haemophilus influenzae.

In addition to detoxifying peroxides generated by aerobic metabolism, the catalases of pathogenic bacteria have also been hypothesized to serve as virulence factors by enabling microorganisms to resist the oxidative bursts of host inflammatory cells. Using transposon mutagenesis of the hktE gene, encoding the Haemophilus influenzae structural gene for catalase, we constructed defined catalase mutants of H. influenzae strains Rd- and Eagan b+. These mutants show no detectable catalase production during exponential or stationary phases or following induction with hydrogen peroxide or ascorbic acid, indicating that hktE is the only functional hydroperoxidase gene present in these two strains of H. influenzae. Exponential-phase cultures of hktE mutants are 8- to 25-fold more sensitive to hydrogen peroxide than the wild type. Using the infant rat model, hktE mutants of strain Eagan b+ were 2.3-fold less virulent than the wild type following intraperitoneal inoculation (P = 0.07). When administered intranasally, the Eagan b+ hktE mutant produced wild-type levels of bacteremia and nasal colonization. The results of this study show that while the H. influenzae hktE gene is important for survival in the presence of peroxides, deletion of the gene produces only a modest reduction in ability to cause lethal sepsis following parenteral challenge and no change in ability to colonize following intranasal inoculation in the infant rat model of infection.

Animals↗
PubMed1999

Infection-associated decline of cape buffalo blood catalase augments serum trypanocidal activity.

Clearance of trypanosomes from the blood of infected Cape buffalo was associated with the development of two responses: (i) complement-dependent and clone-specific lytic activity and (ii) complement-independent trypanocidal activity that was not restricted by trypanosome clone or species. This latter activity was mediated by H2O2 and required the presence of xanthine oxidase in serum but not the addition of purine substrates. Expression of the xanthine oxidase-dependent trypanocidal activity in Cape buffalo serum was coincident with, and required, a decline in its H2O2 catabolic activity. The H2O2 catabolic activity of Cape buffalo serum was due solely to catalase and declined by eightfold around the time that trypanosomes were cleared from the blood, accompanied by a fivefold drop in erythrocyte-associated catalase activity. The Cape buffalo did not develop subsequent parasitemic waves. Clearance of parasitemia in similarly infected cattle was also associated with development of trypanosome clone-specific lytic activity, but not with the acquisition of H2O2-dependent trypanocidal activity in serum, and the cattle supported recurring parasitemia. The lack of trypanocidal activity in pre- and postinfection cattle sera was due to their low content of xanthine oxidase and sustained catalase activity. These data strongly suggest that an infection-induced serum oxidative response, the efficacy of which is amplified by a decline in blood catalase, contributes to suppression of recurring parasitemia in Cape buffalo.

Animals↗
PubMed1984

Genetic mapping of katF, a locus that with katE affects the synthesis of a second catalase species in Escherichia coli.

A class of catalase-deficient mutants that was unlinked to katE was localized between mutS and cys at 59.0 min on the Escherichia coli genome. This locus was named katF. Transposon Tn10 insertions were isolated that mapped in both katE and katF loci. The catalase species present in katE+ and katF+ recombinants was found to be different from the main catalase activities, HPI and HPII, in several respects. It did not have an associated peroxidase activity; it was electrophoretically slower on native polyacrylamide gels; it eluted from DEAE-Sephadex A50 at a higher salt concentration; its Km for H2O2 was 30.9 mM as compared with 3.7 mM for HPI and HPII; its synthesis was not induced by ascorbate; and it did not cross react with HPI-HPII antisera. This new catalase was labeled HPIII.

Ascorbic Acid↗
PubMed1989

Evidence for three differentially regulated catalase genes in Neurospora crassa: effects of oxidative stress, heat shock, and development.

Genetic and biochemical studies demonstrated that Neurospora crassa possesses three catalases encoded by three separate structural genes. The specific activities of the three enzymes varied in response to superoxide-mediated stress, heat shock, and development. The three loci, which we designated cat-1, cat-2, and cat-3, map to the right arms of chromosomes III, VII, and III, respectively. The cat-1-encoded enzyme (designated Cat-1; estimated molecular weight, 315,000; pI 5.2) was the predominant catalase in rapid-growth mycelium, and its activity was substantially increased in paraquat-treated and heat-shocked mycelium. Cat-2 (Mw, 165,000; pI 5.4) was absent from rapid-growth mycelium but present at low levels in conidia and stationary-phase mycelium. It was the predominant catalase in extracts derived from mycelium that had been heat shocked for 2 h. Cat-3 (Mw, 340,000; pI 5.5) was the predominant catalase in extracts from mature conidia.

Age Factors↗
PubMed1995

Purification and characterization of a mesohalic catalase from the halophilic bacterium Halobacterium halobium.

When subjected to the stress of growth in a relatively low-salt environment (1.25 M NaCl), the halophilic bacterium Halobacterium halobium induces a catalase. The protein has been purified to electrophoretic homogeneity and has an M(r) of 240,000 and a subunit size of approximately 62,000. The enzyme is active over a broad pH range of 6.5 to 10.0, with a peak in activity at pH 7.0. It has an isoelectric point of 4.0. This catalse, which is not readily reduced by dithionite, shows a Soret peak at 406 nm. Cyanide and azide inhibit the enzyme at micromolar concentrations, whereas maleimide is without effect. The addition of 20 mM 3-amino-1,2,4-triazole results in a 33% inhibition in enzymatic activity. The tetrameric protein binds NADP in a 1:1 ratio but does not peroxidize NADPH, NADH, or ascorbate. Although the enzymatic activity is maximal when assayed in a 50 mM potassium phosphate buffer with no NaCl, prolonged incubation in a buffer lacking NaCl results in inactive enzyme. Moreover, purification must be performed in the presence of 2 M NaCl. Equally as effective in retaining enzymatic function are NaCl, LiCl, KCl, CsCl, and NH4Cl, whereas divalent salts such as MgCl2 and CaCl2 result in the immediate loss of activity. The catalase is stained by pararosaniline, which is indicative of a glycosidic linkage. The Km for H2O2 is 60 mM, with inhibition observed at concentrations in excess of 90 mM. Thus, the mesohalic catalase purified from H. halobium seems to be similar to other catalases, except for the salt requirements, but differs markedly from the constitutive halobacterial hydroperoxidase.

Amino Acid Sequence↗
PubMed1996

Oxidative stress response in an anaerobe, Bacteroides fragilis: a role for catalase in protection against hydrogen peroxide.

Survival of Bacteroides fragilis in the presence of oxygen was dependent on the ability of bacteria to synthesize new proteins, as determined by the inhibition of protein synthesis after oxygen exposure. The B. fragilis protein profile was significantly altered after either a shift from anaerobic to aerobic conditions with or without paraquat or the addition of exogenous hydrogen peroxide. As determined by autoradiography after two-dimensional gel electrophoresis, approximately 28 newly synthesized proteins were detected in response to oxidative conditions. These proteins were found to have a broad range of pI values (from 5.1 to 7.2) and molecular weights (from 12,000 to 79,000). The hydrogen peroxide- and paraquat-inducible responses were similar but not identical to that induced by oxygen as seen by two-dimensional gel protein profile. Eleven of the oxidative response proteins were closely related, with pI values and molecular weights from 5.1 to 5.8 and from 17,000 to 23,000, respectively. As a first step to understanding the resistance to oxygen, a catalase-deficient mutant was constructed by allelic gene exchange. The katB mutant was found to be more sensitive to the lethal effects of hydrogen peroxide than was the parent strain when the ferrous iron chelator bipyridyl was added to culture media. This suggests that the presence of ferrous iron in anaerobic culture media exacerbates the toxicity of hydrogen peroxide and that the presence of a functional catalase is important for survival in the presence of hydrogen peroxide. Further, the treatment of cultures with a sublethal concentration of hydrogen peroxide was necessary to induce resistance to higher concentrations of hydrogen peroxide in the parent strain, suggesting that this was an inducible response. This was confirmed when the bacterial culture, treated with chloramphenicol before the cells were exposed to a sublethal concentration of peroxide, completely lost viability. In contrast, cell viability was greatly preserved when protein synthesis inhibition occurred after peroxide induction. Complementation of catalase activity in the mutant restored the ability of the mutant strain to survive in the presence of hydrogen peroxide, showing that the catalase (KatB) may play a role in oxidative stress resistance in aerotolerant anaerobic bacteria.

2,2'-Dipyridyl↗
PubMed1997

Isolation and expression of the catA gene encoding the major vegetative catalase in Streptomyces coelicolor Müller.

We isolated the catA gene for the major vegetative catalase from Streptomyces coelicolor Müller. It encodes a polypeptide of 488 residues (55,440 Da) that is highly homologous to typical monofunctional catalases. We investigated catA expression by analyzing both catA mRNA and catalase activity. catA expression was increased by H2O2 treatment but did not increase during stationary phase. A putative catalase (CatB) cross-reactive with anti-CatA antibody appeared during stationary phase and in the aerial mycelium.

Amino Acid Sequence↗
PubMed1998

Posttranscriptional control mediates cell type-specific localization of catalase A during Aspergillus nidulans development.

Two differentially regulated catalase genes have been identified in the fungus Aspergillus nidulans. The catA gene belongs to a class whose transcripts are specifically induced during asexual sporulation (conidiation) and encodes a catalase accumulated in conidia. Using a developmental mutant affected in the brlA gene, which is unable to form conidia but capable of producing sexual spores (ascospores), we demonstrated that the catA mRNA accumulated during induction of conidiation but did not produce CatA protein. In contrast, high levels of catalase A activity were detected in the ascospores produced by this mutant, indicating that the catA gene is posttranscriptionally regulated. The same type of regulation was observed for a catA::lacZ translational gene fusion, suggesting that the catA message 5' untranslated region could be involved in translational control during development. In a wild-type strain, beta-galactosidase activity driven from the catA::lacZ gene fusion was low in hyphae and increased 50-fold during conidiation and 620-fold in isolated conidia. Consistent with this finding spatial expression of the reporter gene was restricted to metulae, phialides, and conidia. Conidium-associated expression was maintained in a stuA mutant, in which the conidiophore cell pattern is severely deranged. catA mRNA accumulation was also observed when vegetative mycelia was subject to oxidative, osmotic, and nitrogen or carbon starvation stress. Nevertheless, catalase A activity was restricted to the conidia produced under nutrient starvation. Our results provide support for a model in which translation of the catA message, accumulated during conidiation or in response to different types of stress, is linked to the morphogenetic processes involved in asexual and sexual spore formation. Our findings also indicate that brlA-independent mechanisms regulate the expression of genes encoding spore-specific products.

Artificial Gene Fusion↗