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At least 649 records · Page 36Linked to original sources
PubMed1998

Legionella pneumophila catalase-peroxidases: cloning of the katB gene and studies of KatB function.

Legionella pneumophila, the causative organism of Legionnaires' pneumonia, is spread by aerosolization from man-made reservoirs, e.g. , water cooling towers and air conditioning ducts, whose nutrient-poor conditions are conducive to entrance into stationary phase. Exposure to starvation conditions is known to induce several virulence traits in L. pneumophila. Since catalase-peroxidases have been extremely useful markers of the stationary-phase response in many bacterial species and may be an avenue for identifying virulence genes in L. pneumophila, an investigation of these enzymes was initiated. L. pneumophila was shown to contain two bifunctional catalase-peroxidases and to lack monofunctional catalase and peroxidase. The gene encoding the KatB catalase-peroxidase was cloned and sequenced, and lacZ fusion and null mutant strains were constructed. Null mutants in katB are delayed in the infection and lysis of cultured macrophage-like cell lines. KatB is similar to the KatG catalase-peroxidase of Escherichia coli in its 20-fold induction during exponential growth and in playing a role in resistance to hydrogen peroxide. Analysis of the changes in katB expression and in the total catalase and peroxidase activity during growth indicates that the 8- to 10-fold induction of peroxidase activity that occurs in stationary phase is attributable to KatA, the second L. pneumophila catalase-peroxidase.

Amino Acid Sequence↗
PubMed2000

Gene cloning and expression of the catalase from the hydrogen peroxide-resistant bacterium Vibrio rumoiensis S-1 and its subcellular localization.

The catalase gene, vktA, of the hydrogen peroxide-resistant bacterium Vibrio rumoiensis S-1 has been isolated and sequenced. Plasmid pBSsa1 was obtained by genome library screening and it complemented a catalase-less mutant, Escherichia coli strain UM2, indicating that pBSsa1 contained the catalase gene (vktA). The vktA gene consisted of an open reading frame of 1530 bp encoding a 508 amino-acid protein with a calculated size of 57657.79 Da. The deduced amino acid sequence showed high homology with that of bacterial group III catalases. Investigation of the subcellular catalase localization using an immuno-electron microscopical technique revealed that a larger amount of VktA catalase is present in the periplasmic space than in the cytoplasm. The periplasmic space of this bacterium can therefore be regarded as a reservoir of VktA catalase in V. rumoiensis S-1.

Journal Article↗
PubMed1964

CATALASE ACTIVITY OF TWO STREPTOCOCCUS FAECALIS STRAINS AND ITS ENHANCEMENT BY AEROBIOSIS AND ADDED CATIONS.

Jones, Dorothy (American Meat Institute Foundation, Chicago, Ill.), R. H. Deibel, and C. F. Niven, Jr. Catalase activity of two Streptococcus faecalis strains and its enhancement by aerobiosis and added cations. J. Bacteriol. 88:602-610. 1964.-The nature of catalase activity noted in two unusual Streptococcus faecalis strains was determined. Enzyme activity was lost slowly when cultures were maintained by daily transfer in test tubes of broth media. Loss of activity could be prevented by aerobic culture. Supplementation of the growth medium with ferric, manganese, and zinc ions, as well as aerobiosis, enhanced catalase activity. However, addition of these cations to cell suspensions or to cell-free extracts did not increase catalase activity. Although oxygen was observed to be one of the reaction end products, the catalase activity was not inhibited by cyanide or azide, and the iron-porphyrin coenzyme of classical catalase was not detected. The enzyme was purified 185-fold by precipitation with ammonium sulfate, followed by chromotography on a diethylaminoethyl cellulose column.

Aerobiosis↗
PubMed1965

CATALASE ACTIVITY IN ANAPLASMA MARGINALE.

Wallace, W. R. (Louisiana State University, Baton Rouge), and G. T. Dimopoullos. Catalase activity in Anaplasma marginale. J. Bacteriol. 91:309-311. 1965.-Extracts of erythrocytes infected with Anaplasma marginale were found to contain more catalase activity than normal erythrocytic preparations. The increase in catalase activity appeared concurrently with increases in the number of erythrocytes containing Anaplasma bodies. Antisera against normal bovine erythrocytes and Anaplasma-infected erythrocytes were prepared in rabbits to test the source of increased catalase activity during anaplasmosis. Antiserum against normal erythrocytes decreased the catalase activity of extracts of normal erythrocytes by 271 units per ml and of partially purified Anaplasma bodies by only 120 units. Rabbit antiserum against Anaplasma-infected bovine erythrocytes removed only 73 units of activity from normal erythrocytes, but decreased the activity of the partially purified Anaplasma bodies by 260 units, indicating the association of catalase with the marginal body.

Anaplasma↗
PubMed1999

Adenoviral gene therapy with catalase suppresses experimental optic neuritis.

OBJECTIVE: To determine if adenoviral-mediated transfer of the gene for catalase (CAT), the reactive oxygen species scavenger, suppresses experimental optic neuritis. CLINICAL RELEVANCE: Gene therapy with CAT delivered by an adeno-associated viral vector was previously shown to suppress experimental optic neuritis. Because the transduction of protein expression with recombinant adeno-associated viral vector is relatively slow, taking weeks to reach full levels, we studied the effects of replication-deficient adenovirus containing CAT in suppressing experimental optic neuritis. Transduction with adenovirus occurs within days of inoculation, thus, it may be more applicable for the treatment of patients with acute optic neuritis. MATERIALS AND METHODS: Replication-deficient adenovirus containing CAT was injected above the right optic nerve heads of SJL/J mice that were simultaneously sensitized for experimental allergic encephalomyelitis. For controls, the left eyes were injected with the replication-deficient adenovirus without CAT or no virus. The histological effects of CAT on the lesions of experimental allergic encephalomyelitis were measured by computerized analysis of the myelin sheath area (for demyelination), optic disc area (for optic nerve head swelling), the extent of the cellular infiltrate, extravasated serum albumin labeled with immunogold (for disruption of the blood-brain barrier), and the in vivo hydrogen peroxide reaction product. RESULTS: After 1 month, cell-specific catalase activity, evaluated by the quantitation of catalase immunogold, was increased about 2-fold each in endothelia, oligodendroglia, astrocytes, and axons of the CAT-inoculated right optic nerves compared with the control left optic nerves. The increased cellular levels of catalase reduced demyelination by 30%, optic nerve head swelling by 25%, cellular infiltration by 26%, disruption of the blood-brain barrier by 61%, and in vivo levels of hydrogen peroxide by 81%. CONCLUSIONS: Adenoviral-mediated gene transfer increased catalase levels in all optic nerve cell types, and it persisted for 1 month after inoculation. The increased cellular levels of catalase suppressed demyelination and blood-brain barrier disruption at the foci in the optic nerve where prior magnetic resonance imaging and histopathologic studies have demonstrated the demyelinating inflammation of experimental and human optic neuritis. Together, they suggest that gene therapy with CAT may be helpful in the treatment of patients with optic neuritis.

Adenoviridae↗
PubMed1998

Analysis of the transcriptional activity of the 5'-flanking region of the rat catalase gene in transiently transfected cells and in transgenic mice.

Transiently transfected cell lines and transgenic mice were used to study the transcriptional activity of the 5'-flanking region of the catalase gene. Fragments of the 5'-flanking region of the rat catalase gene ranging in length from 3,421 base pairs (bp) to 69 bp were fused to the chloramphenicol acetyltransferase (CAT) reporter gene, and the transcriptional activity of the reporter gene was measured following transient transfection in three cell lines: a human hepatoma cell line (HepG2), a porcine kidney epithelial cell line (LLCPK1), and a human glioma cell line (U-138 MG). The 3,421-bp fragment of the 5'-flanking region resulted in a high level of expression of the reporter gene in all three cell lines. Shorter fragments of the 5'-flanking region resulted in a decrease in the level of CAT reporter expression that varied among the three cell lines, implying the presence of tissue-specific regulatory sites. To study the tissue-specific regulation of the catalase promoter, transgenic mice containing the 3,421-bp 5'-flanking sequence attached to the CAT reporter gene were produced, and CAT expression was measured in various tissues of three independent transgenic lines. CAT activity was consistently high in muscle tissue (heart, skeletal muscle, and diaphragm) and low in most other tissues studied, particularly in liver and kidney. In contrast, the endogenous expression of catalase is low in muscle and high in liver and kidney; thus, the tissue-specific expression of the reporter gene driven by the 3,421-bp fragment of the 5'-flanking region of the catalase gene was not similar to the expression of the endogenous catalase gene.

Animals↗
PubMed1999

Transcriptional activation of Cu/Zn superoxide dismutase and catalase genes by panaxadiol ginsenosides extracted from Panax ginseng.

Superoxide dismutase (SOD) converts superoxide radical to H(2)O(2), which is in turn broken down to water and oxygen by catalase. Thus, SOD and catalase constitute the first coordinated unit of defence against reactive oxygen species. A wide variety of chemical and environmental factors are known to induce these antioxidant enzymes. Here, we examined the effect of ginseng saponins on the induction of SOD and catalase gene expression. To explore this possibility, the upstream regulatory promoter region of Cu/Zn superoxide dismutase (SOD1) and catalase genes were linked to the chloramphenicol acetyltransferase (CAT) structural gene and introduced into human hepatoma HepG2 cells. Total saponin and panaxatriol did not activate the transcription of SOD1 and catalase genes but panaxadiol increased the transcription of these genes about 2-3 fold. Among the panaxadiol ginsenosides, the Rb(2) subfraction appeared to be a major inducer of SOD1 and catalase genes. The specificity of the Rb(2) effect was further confirmed by time course- and dose-dependent induction experiments. These results suggest that the panaxadiol fraction and its ginsenosides could induce the antioxidant enzymes which are important for maintaining cell viability by lowering the level of oxygen radical generated from intracellular metabolism.

Carcinoma, Hepatocellular↗
PubMed1980

Efficiency of bovine liver catalase as a catalyst to cleave H2O2 added continually to buffer solutions.

Empirical estimations of H2O2 concentration in a system containing bovine liver catalase and continually supplied with H2O2 were done to evaluate the efficiency of the enzyme to cleave H2O2. It was found that the continuous addition of H2O2 leads to the formation of steady-state concentrations of H2O2 in the medium. At a constant catalase concentration both the level and the duration of the steady state are dependent on the flow rate of H2O2. The increase of the catalase concentration in the medium does not change the steady-state level, it merely leads to the maintenance of the steady state for longer durations. At higher flow rates of H2O2, no steady state could be maintained, even when catalase was present in high excess. The incomplete cleavage of H2O2 by catalase under these conditions is due to the low affinity of catalase toward H2O2 (high K m value, apparent K m = 0.1M H2O2) and to the rapid inactivation of the enzyme during the continuous addition of H2O2.

Animals↗
PubMed1986

Properties of catalase activity in vegetative and sporulating cells of yeast Saccharomyces cerevisiae.

Properties of catalase activities have been examined in the intact cells of early stationary phase and cells 3 hr after transfer to sporulation medium in Saccharomyces cerevisiae. The catalase activities of the two cells had a broad optimal pH from 6 to 8. Catalase activity in the intact cells increased throughout a 4-hr period of the observation following transfer to sporulation medium. Almost all the catalase activity in vegetative cells was lost by the treatment at 60 degrees C for 10 min. Catalase activities of both cells were inhibited by KCN, NaN3, o-phenanthroline, and PCMB. The catalase activity of the vegetative cells was slightly more inhibited and inactivated than that of the sporulating cells by the inhibitors and by the treatment with HCl or NaOH.

Catalase↗
PubMed1995

Comparison of isoniazid oxidation catalyzed by bacterial catalase-peroxidases and horseradish peroxidase.

The physical properties and activities of the purified catalase-peroxidase hydroperoxidase I (HPI) of Escherichia coli (EcHPI) and HPI with a carboxyl-terminal extension of Mycobacterium tuberculosis (MtHPI-e) are compared to those of commercial preparations of horseradish peroxidase (HRP). The catalase-peroxidase proteins had similar absorption spectra and differed primarily in that MtHPI-e has a higher peroxidatic to catalatic activity ratio than EcHPI. Trypsin cleavage of MtHPI-e resulted in the formation of an active catalase-peroxidase lacking the carboxyl-terminal extension. The three enzymes, HRP, MtHPI-e, and EcHPI, mediated the isoniazid- and H2O2-dependent production of radical species, as detected by nitroblue tetrazolium reduction. A constant flux of H2O2, generated in situ from glucose oxidase and glucose was used. MtHPI-e was more effective at isoniazid-dependent radical production than EcHPI and HRP. Similar qualitative results were obtained by staining nondenaturing polyacrylamide gels for activity with nitroblue tetrazolium in the presence of isoniazid and H2O2. The absorbance spectrum of HRP exhibited changes during incubation with isoniazid and H2O2 consistent with the formation of several typical reaction intermediates, whereas the catalase-peroxidases exhibited no distinct spectral changes. The results suggest that the sensitivity of M. tuberculosis to isoniazid may be the result of isoniazid-dependent radical formation by the catalase-peroxidase in the absence of other catalase activities to remove substrate H2O2.

Bacterial Proteins↗
PubMed2000

Decreased mitochondrial hydrogen peroxide release in transgenic Drosophila melanogaster expressing intramitochondrial catalase.

The objective of this study was to develop strategies for manipulating oxidative stress transgenically in a multicellular organism. Ectopic catalase was introduced into the mitochondrial matrix, which is the main intracellular site of H2O2 formation and where catalase is normally absent. Transgenic Drosophila melanogaster were generated by microinjection of a P element construct, containing the genomic catalase sequence of Drosophila, with the mitochondrial leader sequence of ornithine aminotransferase inserted upstream of the coding region. Total catalase activities in whole-body homogenates of 10-day-old flies from four transgenic lines were approximately 30-160% higher than those from the parental and four vector-only control lines. Expression of catalase in the mitochondrial matrix was confirmed by immunoblotting and catalase activity assays. Mitochondrial release of H2O2 was decreased by approximately 90% in the transgenic lines when compared to levels in vector-only controls. This in vivo system provides a novel model for examining the functional significance of decreased mitochondrial H2O2 release.

Animals↗
PubMed1995

Transient overexpression of catalase does not inhibit TNF- or PMA-induced NF-kappa B activation.

H2O2 has been proposed as a second messenger involved in cell signaling for NF-kappa B activation. In the present study, this hypothesis was tested by transiently overexpressing catalase, a specific scavenger of H2O2, in COS-1 cells. A mammalian expression vector was constructed by incorporating catalase gene from pCAT10 clone into the unique EcoRI site of the pSG5 vector which contains the SV-40 promoter. Transient transfection of the catalase expression vector by the DEAE-dextran method led to a four-fold increase in catalase activity and catalase content as detected by immunoblot analysis. This level of increase was detected in both nuclear/mitochondrial- and cytosolic/microsomal fractions. Overexpression of catalase, however, did not block TNF- or PMA-induced NF-kappa B activation. These results weaken the hypothesis that H2O2 is a second messenger for TNF- and PMA-signaling for NF-kappa B activation.

Animals↗
PubMed1998

Glutathione and catalase provide overlapping defenses for protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae.

Glutathione (GSH) is an abundant and ubiquitous low-molecular-weight thiol which has proposed roles in many cellular processes including protection against the deleterious effects of reactive oxygen species. Our experiments have addressed the role of GSH in protection against hydrogen peroxide in the yeast Saccharomyces cerevisiae, and have shown that GSH and catalase provide overlapping defense systems. GSH appears to be the primary antioxidant for protection against hydrogen peroxide since mutants lacking GSH (gsh1) or glutathione reductase (glr1) are sensitive, whereas, strains lacking catalase A (cta1) or catalase T (ctt1) are unaffected in resistance to this oxidant. Furthermore, following treatment with hydrogen peroxide, the levels of oxidized, protein-bound and extracellular GSH were all increased at the expense of intracellular GSH. However, there are two lines of evidence that indicate catalases are required in the absence of GSH; firstly, strains that lack both catalase A and T accumulate increased levels of oxidized glutathione following treatment with hydrogen peroxide; and secondly, deletion of catalase genes exacerbates the hydrogen peroxide sensitivity of glr1 and gsh1 mutants.

Antioxidants↗
PubMed1995

Crystal structure of Proteus mirabilis PR catalase with and without bound NADPH.

A catalase from a peroxide resistant mutant of Proteus mirabilis binds NADPH tightly. Interestingly, this enzyme can be stripped of NADPH without loss of the catalatic activity. It is the only known non-mammalian catalase able to bind NADPH. The structure without cofactor was solved by molecular replacement using the structure of beef liver catalase as a model. The structure was refined to an R-factor of 19.3% in the range 8 to 2.2 A resolution. According to the sequence, a methionine sulphone was positioned in the haem active site. This oxidized form of methionine is particular to Proteus mirabilis catalase and likely to produce some steric hindrance in the active site. Two important water molecules are positioned in the haem distal site. These two water molecules are not located in the structure of beef liver catalase, but are supposed to account for the catalytic mechanism. The liganded form was obtained by soaking crystals of the unliganded form into an NADPH solution. The structure was refined to an R-factor of 15.9% in the range of 8 to 3.1 A resolution using the unliganded structure as a model. The NADPH was clearly located in the electron density map with the same conformation as in beef liver catalase. The NADPH binding induces slight structural changes. However, the imidazole ring of a histidine residue (His284) rotates about 50 degrees to accommodate the cofactor. The electron transfer from NADPH to the haem molecule was examined and several pathways are proposed.

Amino Acid Sequence↗
PubMed2000

Effects of hydrogen peroxide scavenger Catalase on villous microcirculation in the rat small intestine in a model of inflammatory bowel disease.

This study was conducted to quantify the effect of systemic Catalase, a hydrogen peroxide scavenger, on villous microcirculation in the inflamed small intestine of the rat. Intestinal inflammation was induced with s.c. application of Indomethacin. Intravital fluorescence microscopy and FITC-labeled erythrocytes were used to quantify erythrocyte velocity and arteriolar diameter in the main arteriole of the villi in the terminal ileum following i.v. application of Catalase in the inflamed intestine, and the blood flow was calculated. Control groups were formed for Ringer's lactate, Catalase and Indomethacin, respectively. We found that villous blood flow was significantly increased in the in the inflamed intestine. Application of Catalase led to a significant decrease in villous perfusion, but had no effect in the control group. The increase in villous blood flow was accompanied by changes in the diameter of the main arteriole. This effect on arteriolar diameter was reversed by i.v. Catalase. Our results provide evidence that systemic application of Indomethacin leads to vasodilatation of the main arteriole of the villus in the rat ileum and hyperemia in the mucosa. Hyperemia and the vascular diameter of the main arteriole were significantly reduced by H(2)O(2)-scavenger Catalase, suggesting that endogenous H(2)O(2) may be one of the mediators of hyperemia in the mucosa in this animal model of intestinal inflammation.

Animals↗
PubMed1996

Middle ear catalase distribution in an animal model of otitis media.

Increasing evidence implicates free radicals in the pathogenesis of inflammatory disease, including otitis media. The anti-oxidant enzymes catalase, glutathione peroxidase and superoxide dismutase protect tissues from the destructive effects of free radicals. Our previous work has shown depressed levels of superoxide dismutase in the infected middle ears of a guinea pig model of otitis media in comparison with normal control ears. We studied the distribution and relative abundance of catalase in the middle ear of this animal model in an effort to elucidate the role free radicals play in the pathogenesis of otitis media. Catalase distribution was mapped immunohistochemically in the middle ears of guinea pigs with induced streptococcus otitis media, and compared with normal control ears. In the control ears, catalase was localized to the epithelium of the middle ear mucosa, with scant distribution in the submucosa. The infected ears demonstrated inflammatory cell invasion with hyperemia and submucosal edema. Catalase was localized to the epithelium and had scant distribution in the submucosa. This distribution was similar to that found previously with superoxide dismutase. Enzyme-linked immunosorbent assay of catalase demonstrated a mean value of 1.00 +/- 0.06 microgram/mg protein in the control ears, and 1.06 +/- 0.12 microgram/mg in the infected ears, but these two values were not statistically different.

Acute Disease↗
PubMed1995

Variations in peroxisomal catalase of neonatal rat hepatocyte subpopulations. Effect of pre- and postnatal exposure to alcohol.

Alcohol consumption during pregnancy is teratogenic and induces severe alterations in hepatocytes. In the hepatocyte peroxisomal system, ethanol is converted in the presence of H2O2 to acetaldehyde and water. Therefore, peroxisomal catalase also acts as an antioxidant defence mechanism by removing H2O2 and preventing the formation of hydroxyl radicals in the cell. Alterations in peroxisomal catalase after pre- and pre+postnatal alcohol exposure were investigated in the rat. The effect of pre- and postnatal exposure to ethanol on hepatocyte subpopulations was analysed in isolated hepatocytes originating from periportal, intermediate and perivenous zones. Analysis of catalase revealed that the total activity and content of this enzyme were higher in 12-day-old cells than in cells from newborns and that this increment was more pronounced in treated cells. In controls, the amount of peroxisomal catalase increased mainly in periportal cells, whereas alcohol exposure induced a significant increase in the catalase of perivenous hepatocytes. We conclude that pre- and postnatal alcohol exposure mainly affects the perivenous hepatocyte peroxisomes and that the increase in peroxisomal catalase could constitute a defence mechanism against free radical generation induced by alcohol exposure during the perinatal period.

Animals↗
PubMed1981

Superoxide dismutase, catalase, and glutathione peroxidase in the swim bladder of the physoclistous fish, Opsanus tau L.

The antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase were measured in the rete mirabile and gas gland epithelium area of the swim bladder of the toadfish Opsanus tau. When the concentration of enzyme in the swim bladder was compared with the concentration in other organs (kidney, heart, gills) of the same fish, the swim bladder was found to have the highest concentration of superoxide dismutase but relatively low levels of glutathione peroxidase and catalase. Cytochemical assay for the peroxidatic activity of catalase confirmed that virtually no catalase is present in epithelial cells of the gas gland. A similar assay for peroxidase revealed a cyanide-sensitive peroxidase in the multilamellar bodies of these cells. Most of the catalase and peroxidase in the rete mirabile appears to be confined to the granules of neutrophils and the cytoplasm of erythrocytes. Enzyme activity in the neutrophils is not inhibited by 10(-1) M KCN. Cyanide does not appear to inhibit the peroxidase activity in erythrocytes but has little effect on catalase in these cells.

Air Sacs↗