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Microinjection of catalase cDNA prevents hydrogen peroxide-induced motoneuron death.

Oxidative stress is believed to play a central role in the pathogenesis of amyotrophic lateral sclerosis (ALS). We investigated the protective effects of overexpression of catalase in primary cultures of rat spinal motoneurons against the oxidative stress of hydrogen peroxide. Using microinjection, catalase-encoding cDNA was transferred into the motoneurons. In another approach, motoneurons were injected with a catalase solution. Both procedures elevated the intracellular antioxidant status of the cultured motoneurons as evidenced by a significant protection against H2O2 toxicity. We conclude that modulating the expression of enzymes involved in cellular defense against oxidative stress can render cells more resistant to oxidant toxicity.

Animals↗

Catalase over-expression protects striatal neurons from transient focal cerebral ischemia.

Reactive oxygen species (ROS) play key roles in the cascade of brain injury after stroke, and strategies to increase the antioxidant defenses of neurons after stroke hold great promise. In this study we evaluate the neuroprotective potential of using a herpes simplex viral vector to over-express catalase in rats. Vector was microinfused into the striatum either prior to or after middle cerebral artery occlusion (MCAO). Catalase over-expression was protective (relative to control vector) when the vector was delivered 14-16 h prior to ischemia, but not when delivered after ischemia. Thus, the timing of catalase over-expression relative to ischemia is a critical variable determining its potential therapeutic value.

Animals↗

Parenteral superoxide dismutase plus catalase diminishes pancreatic edema in sodium taurocholate-induced pancreatitis in the rat.

Scavengers of toxic oxygen reduction products have been reported to reduce the inflammatory reaction in some models of pancreatitis. In a blinded study, the effect of parenteral pretreatment with superoxide dismutase plus catalase was compared with placebo on pancreatitis induced in rats by infusion of 0.25% or 2% sodium taurocholate into the hepatopancreatic duct. The degree of inflammation was assessed by macroscopic examination of the pancreas, dry/wet weight ratios of pancreatic specimens, amylase activity in plasma and peritoneal exudate, the weight of the exudate, and its content of total protein. All parameters were indicative of a more severe inflammation in rats given the higher concentration of sodium taurocholate. The only significant effect of the superoxide dismutase plus catalase treatment was a moderate reduction of the dry/wet weight ratio, i.e., pancreatic edema, in rats given 2% sodium taurocholate. Our results indicate that toxic oxygen reduction products, available for interception by parenterally administered superoxide dismutase plus catalase, are of only minor importance in the pathogenesis of sodium taurocholate-induced pancreatitis in the rat.

Amylases↗

EUK-134, a synthetic superoxide dismutase and catalase mimetic, protects rat kidneys from ischemia-reperfusion-induced damage.

The effect of a new synthetic superoxide dismutase and catalase mimetic was investigated on renal ischemia-reperfusion syndrome in rats. Synthetic salen-manganese complexes have characteristics that might facilitate their potential usefulness as therapeutic agents: (1) unlike proteinaceous antioxidant enzymes, synthetic complexes, due to their low molecular weight, have a better stability and bioavailability; (2) they have a catalytic activity enhancing their efficiency over noncatalytic reactive oxygen metabolite scavengers; and finally, (3) exhibiting combined superoxide dismutase and catalase activity, they destroy both superoxide anions and hydrogen peroxides, thereby enhancing their protective effect on ischemically injured tissues. One such compound, EUK-134, was tested in uninephrectomized rats that underwent a left renal artery clamping. After a 75-min left renal artery clamping, a single intravenous injection of EUK-134 at 0.2 mg/kg, just before unclamping, provided significantly better renal function recovery during the week after the ischemic insult compared with recovery of untreated animals. Two hours after several periods of renal ischemia (30, 45, 60, and 75 min of left renal artery clamping), EUK-134 given at a similar dose significantly improved the glomerular filtration rate after an acute ischemia of 30 and 45 min, as assessed by EDTA 51Cr. Overall, these results show that synthetic superoxide dismutase-catalase mimetics such as EUK-134 can protect ischemically injured rat kidneys from ischemia-reperfusion syndrome when administered just before reperfusion.

Animals↗

CYP2E1 and catalase influence ethanol sensitivity in the central nervous system.

OBJECTIVES: Genetic factors are known to influence the sensitivity and tolerance to ethanol in humans and laboratory animals. Ethanol is metabolized to acetaldehyde mainly by the alcohol dehydrogenase pathway (ADHs) and, to a lesser extent, by microsomal oxidization (CYP2E1) and the catalase-H2O2 system. METHODS: In this study, we examined the role of CYP2E1 and catalase in ethanol metabolism and sensitivity, using transgenic knockout Cyp2e1(-/-) mice, acatalasemic (Cs/Cs) mice, double mutant Cyp2e1(-/-)/Cs/Cs mice and their respective wild-type counterparts 129/sv, C3H/HeJ, 129/sv X C3H/HeJ mice. Ethanol was administered to the mouse lines and ethanol pharmacokinetics and sleep times were evaluated. RESULTS: Although the rates of whole blood ethanol elimination following i.p. administration were found to be similar regardless of dose or genetic stock, Cs/Cs, Cyp2e1(-/-) and Cyp2e1(-/-)/Cs/Cs mice exhibited longer ethanol-induced sleep times, especially at higher ethanol doses. This infers that there is less acetaldehyde produced in the brains of these animals and is in opposition to the idea that increased acetaldehyde increases the actions of ethanol. The Cyp2e1(-/-) animals produced lower whole blood levels of acetaldehyde than wild-type controls; however, this difference was seen only at higher doses of ethanol. The amount of acetaldehyde produced following the incubation of ethanol with liver and brain microsomes was greater in tissues derived from 129/sv than in those from Cyp2e1(-/-) mice. CONCLUSIONS: Although the contribution of CYP2E1 and catalase in ethanol oxidation may be of little significance, these enzymes appear to play a significant role in ethanol sensitivity in the brain.

Acetaldehyde↗

Prevention of apoptosis as a possible mechanism behind improved cryoprotection of hematopoietic cells by catalase and trehalose.

BACKGROUND: Our previous in vitro work has shown the usefulness of membrane stabilizers and antioxidants as additives in conventional freezing medium to freeze mouse and human hematopoietic cells. The present work was carried out using murine model to test the in vivo engraftment ability of mouse bone marrow frozen with (test cells) or without (control cells) addition of a combination of trehalose and catalase in the medium containing 10% dimethyl sulfoxide (DMSO). METHODS: Viability, nucleated cell recovery, and progenitor content of revived cells were measured. Freezing efficacy was tested by in vivo assays like colony forming unit-spleen (CFU-S), pre-CFU-S, and short-term engraftment of frozen marrow in irradiated mice. Long-term engraftment ability of frozen marrow was assessed using a Ly5.1-Ly 5.2 chimera model. Levels of apoptosis and reactive oxygen species (ROS) generated in revived cells were estimated. The former by Annnexin V, TUNEL, and DNA laddering and the latter by DCFH-DA probe. RESULTS: Our results show that the combination of catalase and trehalose with 10% DMSO improves freezing efficacy not only in terms of viability, cell recovery, and progenitor content but also by in vivo assays like CFU-S, pre-CFU-S, and short- and long-term engraftment. Both the level of apoptosis and ROS generation were considerably reduced in test set as compared to control set. CONCLUSIONS: We conclude that inclusion of a combination of trehalose and catalase in conventional freezing medium leads to enhanced engraftment potential of cryopreserved mouse bone marrow cells probably by preventing apoptotic cell death. Our observation using animal model may have significant clinical implications.

Animals↗

Streptococcus didelphis sp. nov., a streptococcus with marked catalase activity isolated from opossums (Didelphis virginiana) with suppurative dermatitis and liver fibrosis.

beta-Haemolytic, catalase-positive, Gram-positive cocci that formed chains in broth media but did not react with Lancefield group antisera were isolated from skin lesions, spleen, liver and lungs of nine opossums, including eight from a research colony and one from a wildlife rehabilitation organization. The isolates had vigorous catalase activity that was retained on initial passage on non-blood-containing media, but this activity was lost in subsequent passages. The use of standard phenotypic tests did not lead to satisfactory identification of these organisms beyond the genus level, even if the aberrant catalase reaction was not considered. The 16S rRNA gene sequence of the isolates was most similar (96%) to Streptococcus dysgalactiae, but distinct from that species as 16S rRNA gene similarity of different strains of S. dysgalactiae was > 99%. Characterization of biochemical reactions and cell-wall fatty acid profiles also revealed significant differences between the opossum isolates and all other known Streptococcus spp., thus it is proposed as a new species with the name Streptococcus didelphis, sp. nov. The type strain is ATCC 700828T.

Animals↗

Effect of endotoxin treatment and tumour induction on liver catalase activity in mice.

Catalase activity in liver homogenates was studied in normal and low endotoxin (LPS)-responder mice treated with various doses of LPS from S. typhimurium B or bearing tumours induced by 3-methylcholanthrene. In normal LPS-responder (C3H/f) mice a dose of 40 micrograms LPS or tumour induction caused a reduction of catalase activity of about 50%. In low responder (C3H/HeJ) mice a reduction of the enzyme activity of over 40% was observed at a dose of 200 micrograms LPS. Tumour induction had no effect. In tumour-bearing mice of both strains the presence of a tumour seemed to interfere with the ability of LPS to depress hepatic catalase activity. Since a reduction of the enzyme activity in response to LPS or tumour induction seemed to be influenced by the LPS responsiveness of the mice, this study suggests that there could be common mediators of this effect. It is also possible that tumour induction might influence host responses to LPS.

Animals↗

Catalase activity is necessary for heat-shock recovery in Aspergillus nidulans germlings.

To understand the molecular mechanisms induced by stress that contribute to the development of tolerance in eukaryotic cells, the filamentous fungus Aspergillus nidulans has been chosen as a model system. Here, the response of A. nidulans germlings to heat shock is reported. The heat treatment dramatically increased the concentration of trehalose and induced the accumulation of mannitol and mRNA from the catalase gene catA. Both mannitol and catalase function to protect cells from different reactive oxygen species. Treatment with hydrogen peroxide increased A. nidulans germling viability after heat shock whilst mutants deficient in catalase were more sensitive to a 50 degrees C heat exposure. It is concluded that the defence against the lethal effects of heat exposure can be correlated with the activity of the defence system against oxidative stress.

Aspergillus nidulans↗

Catalase has a novel protective role against electrophile killing of Xanthomonas.

The ability of XANTHOMONAS: campestris pv. phaseoli to protect itself against lethal concentrations of man-made (N:-ethylmaleimide, NEM) and endogenously produced (methylglyoxal, MG) electrophiles was investigated. Pretreatment of X. c. pv. phaseoli with a low concentration of NEM induced protection against lethal concentrations of NEM and MG. MG pretreatment weakly induced protection against NEM but not against MG itself. NEM-induced protection against electrophile killing required new protein synthesis and was abolished by the addition of a protein synthesis inhibitor. By contrast, MG-induced protection against NEM killing was independent of de novo protein synthesis. X. c. pv. phaseoli harbouring an expression vector carrying a catalase gene was over 100-fold more resistant to MG and NEM killing. High expression levels of genes for other peroxide-protective enzymes, such as those for alkyl hydroperoxide reductase (ahpC and ahpF) and ohr, failed to protect against electrophile killing. Thus, catalase appears to have a novel protective role(s) against electrophile toxicity. This finding suggests that in X. c. pv. phaseoli NEM and MG toxicity might involve accumulation and/or increased production of H(2)O(2). This idea was supported by the observation that addition of 10 mM sodium pyruvate, a compound that can react chemically with peroxide or hydroxyl radical scavengers (DMSO and glycerol), was found to protect XANTHOMONAS: from electrophile killing. The protective role of catalase and the role of H(2)O(2) in electrophile toxicity are novel observations and could be generally important in other bacteria. In addition, unlike other bacteria, XANTHOMONAS: in stationary phase was more susceptible to electrophile killing compared to cells in exponential phase.

Adaptation, Physiological↗

The mycelium-associated Streptomyces reticuli catalase-peroxidase, its gene and regulation by FurS.

During early stages of growth, Streptomyces reticuli synthesizes a hyphae-associated, haem-containing enzyme which exhibits catalase and peroxidase activities with broad substrate specificity (CpeB). The purified dimeric enzyme (160 kDa) consists of two identical subunits. Using anti-CpeB antibodies and an expression- as well as a mini-library, the corresponding cpeB gene was identified and sequenced. It encodes a protein of 740 aa with a molecular mass of 81.3 kDa. The deduced protein shares the highest level of amino acid identity with KatG from Caulobacter crescentus and Mycobacterium tuberculosis, and PerA from Bacillus stearothermophilus. Streptomyces lividans transformants carrying cpeB and the upstream-located furS gene with its regulatory region on the bifunctional vector pWHM3 produced low or enhanced levels of CpeB in the presence or absence of Fe ions, respectively. An in-frame deletion of the major part of furS induces increased CpeB synthesis. The data imply that FurS regulates the transcription of cpeB. The deduced FurS protein is rich in histidine residues, contains a putative N-terminally situated helix-turn-helix motif and has a molecular mass of 15.1 kDa. It shares only 29% amino acid identity with the Escherichia coli ferric uptake regulator (Fur) protein, but about 64% with FurA deduced from the genomic sequences of several mycobacteria. The predicted secondary structures of FurS and FurA are highly similar and considerably divergent from those of the E. coli Fur. In contrast to some Gram-negative bacteria, within several mycobacteria an intact furA gene or a furA pseudogene is upstream of a catalase-peroxidase (katG) gene predicted to encode a functional or a non-functional (Mycobacterium leprae) enzyme. Thus the data obtained for Streptomyces reticuli are expected to serve as an additional model to elucidate the regulation of mycobacterial catalase-peroxidase genes.

Amino Acid Sequence↗

Catellicoccus marimammalium gen. nov., sp. nov., a novel Gram-positive, catalase-negative, coccus-shaped bacterium from porpoise and grey seal.

Two strains of an unknown Gram-positive, catalase-negative, facultatively anaerobic, coccus-shaped bacterium, originating from a porpoise and a grey seal, were characterized using phenotypic, biochemical and molecular phylogenetic methods. Chemical studies revealed the presence of a cell-wall murein based on L-lysine (type L-lys-gly-D-Asp) and a DNA G+C content of 38 mol%. Comparative 16S rRNA gene sequencing showed that this unidentified coccus-shaped organism formed a hitherto unknown subline closely related to, albeit distinct from, a number of other catalase-negative genera which included Enterococcus, Melissococcus, Tetragenococcus and Vagococcus. Other known Gram-positive, catalase-negative taxa were more distantly related. Tree-branching considerations and sequence divergence values of >6% with recognized taxa were indicative of this novel bacterium representing a separate genus. Based on phenotypic and phylogenetic evidence, it is proposed that this unknown bacterium, recovered from a porpoise and a grey seal, be classified as a novel genus and species, Catellicoccus marimammalium gen. nov., sp. nov. The type strain is M35/04/3T (=CCUG 49459T=CIP 108575T).

Anaerobiosis↗

Structural studies of Proteus mirabilis catalase in its ground state, oxidized state and in complex with formic acid.

The structure of Proteus mirabilis catalase in complex with an inhibitor, formic acid, has been solved at 2.3 A resolution. Formic acid is a key ligand of catalase because of its ability to react with the ferric enzyme, giving a high-spin iron complex. Alternatively, it can react with two transient oxidized intermediates of the enzymatic mechanism, compounds I and II. In this work, the structures of native P. mirabilis catalase (PMC) and compound I have also been determined at high resolution (2.0 and 2.5 A, respectively) from frozen crystals. Comparisons between these three PMC structures show that a water molecule present at a distance of 3.5 A from the haem iron in the resting state is absent in the formic acid complex, but reappears in compound I. In addition, movements of solvent molecules are observed during formation of compound I in a cavity located away from the active site, in which a glycerol molecule is replaced by a sulfate. These results give structural insights into the movement of solvent molecules, which may be important in the enzymatic reaction.

Amino Acids↗

Structure of human erythrocyte catalase.

Catalase (E.C. 1.11.1.6) was purified from human erythrocytes and crystallized in three different forms: orthorhombic, hexagonal and tetragonal. The structure of the orthorhombic crystal form of human erythrocyte catalase (HEC), with space group P2(1)2(1)2(1) and unit-cell parameters a = 84.9, b = 141.7, c = 232.5 A, was determined and refined with 2.75 A resolution data. Non-crystallographic symmetry restraints were employed and the resulting R value and R(free) were 0.206 and 0.272, respectively. The overall structure and arrangement of HEC molecules in the orthorhombic unit cell were very similar to those of bovine liver catalase (BLC). However, no NADPH was observed in the HEC crystal and a water was bound to the active-site residue His75. Conserved lattice interactions suggested a common growth mechanism for the orthorhombic crystals of HEC and BLC.

Animals↗

Unique oligomeric intermediates of bovine liver catalase.

Catalases, although synthesized from single genes and built up from only one type of subunit, exist in heterogeneous form with respect to their conformations and association states in biological systems. This heterogeneity is not of genetic origin, but rather reflects the instability of this oligomeric heme enzyme. To understand better the factors that stabilize the various association states of catalase, we performed studies on the multimeric intermediates that are stabilized during guanidine-hydrochloride- and urea-induced unfolding of bovine liver catalase (BLC). For the first time, we have observed an enzymatically active, folded dimer of native BLC. This dimer has slightly higher enzymatic activity and altered structural properties compared to the native tetramer. Comparative studies of the effect of NaCl, GdmCl, and urea on BLC show that cation binding to negatively charged groups present in amino acid side chains of the enzyme leads to stabilization of an enzymatically active, folded dimer of BLC. Besides the folded dimer, an enzymatically active expanded tetramer and a partially unfolded, enzymatically inactive dimer of BLC were also observed. A complete recovery of native enzyme was observed on refolding of expanded tetramers and folded dimers; however, a very low recovery (maximum of approximately 5%) of native enzyme was observed on refolding of partially unfolded dimers and fully unfolded monomers.

Anilino Naphthalenesulfonates↗

Association study between catalase gene polymorphisms and the susceptibility to vitiligo in Korean population.

Vitiligo is an acquired pigmentary disorder characterized by well-circumscribed depigmented patches. Autoimmune, self-destruction, neural, and genetic theories have been proposed for the pathogenesis of vitiligo. Reactive oxygen species play an important role in the physiology of cell damage, and catalase is known to regulate oxidative stress. Reduced catalase enzyme activity and accumulation of excessive hydrogen peroxide were observed in vitiligo. To examine whether catalase gene polymorphisms are associated with vitiligo patients in Korean population, we investigated two CAT gene polymorphisms including (T/C) BstX I (A/T) Hinf I in 118 vitiligo patients and 200 healthy volunteers. The CAT gene genotype distribution and allele frequency were not significantly different between vitiligo patients and healthy controls. But, the haplotype of two polymorphisms was associated with vitiligo. This study suggests possible association between the CAT gene and the vitiligo susceptibility.

Adult↗

Alcohol oxidase and catalase in peroxisomes of methanol-grown Candida boidinii.

Microbodies, designated as peroxisomes because of their enzyme complement, have been isolated from methanol-grown cells of Candida boidinii. Spheroplast lysates were separated on non-continuous Ficoll density gradients, resulting in a mitochondrial fraction and a peroxisome fraction. Estimates of purity using the mitochondrial enzyme markers suggested that the contamination of mitochondria in the peroxisome fraction was about 2-3%. As shown by electron microscopy the peroxisomes were 0.4-0.6 mum in diameter and contained crystalloid inclusions. Alcohol oxidase and catalase, which catalyse the oxidation of methanol to formaldehyde in Candida boidinii, could be localized within the peroxisomes. Gel-electrophoretic studies of the peroxisome fraction demonstrated that it contained only two predominant protein bands consistent with alcohol oxidase and catalase. No alcohol oxidase and catalase activity was found in mitochondria.

Alcohol Oxidoreductases↗

Microbody of methanol-grown yeasts. Localization of catalase and flavin-dependent alcohol oxidase in the isolated microbody.

Profuse appearance of microbodies was observed in the cells of methanol-utilizing yeasts in connection with the enhanced catalase activity. These microbodies were isolated successfully by means of sucrose gradient centrifugation from the methanol-grown cells of Kloeckera sp. no. 2201. Localization of a flavin-dependent alcohol oxidase as well as characteristic microbody enzymes (catalase and D-amino acid oxidase) were ascertained in the isolated microbodies, whereas formaldehyde and formate dehydrogenases were detected in the cytoplasmic region. Localization of catalase in the isolated microbody was also demonstrated by the cytochemical technique with 3,3'-diaminobenzidine.

Alcohol Oxidoreductases↗