Extracellular Catalase Activity Research Articles

Algae promotes the biogenic oxidation of Mn(II) by accelerated extracellular superoxide production

Microbial manganese (Mn) oxidation, predominantly occurs within the anaerobic-aerobic interfaces, plays an important role in environmental pollution remediation. The anaerobic-aerobic transition zones, notably riparian and lakeside zones, are hotspots for algae-bacteria interactions. Here, we adopted a Mn(II)-oxidizing bacterium Pseudomonas sp. QJX-1 to investigate the impact of algae on microbial Mn(II) oxidation and verify the underlying mechanisms. Interestingly, we achieved a remarkable enhancement in bacterial Mn(II)-oxidizing activity within the algae-bacteria co-culture, despite the inability to oxidize Mn(II) for the algae used in this study. In addition, the bacterial density almost remains constant in the presence of algal cells. Therefore, the increased Mn(II) oxidation by QJX-1 in the presence of algae cannot be due to the increased biomass. Within this co-culture system, the Mn(II) oxidation rate surged to an impressive 0.23 mg/L/h, in stark contrast to 0.02 mg/L/h recorded within pure QJX-1 system. The presence of algae could inhibit the Fe-S cluster activity of QJX-1 by the produced active substance in co-culture, and result in the acceleration of extracellular superoxide production due to the impairment of electron transfer functions located in QJX-1 cell membranes. Moreover, elevated peroxidase gene expression and heightened extracellular catalase activity not only expedited Mn(II) ions oxidation but also facilitated conversion of intermediate Mn(III) ions into microbial Mn oxides, achieved through the degradation of hydrogen peroxide. Therefore, the acceleration of extracellular superoxide production and the decomposition of hydrogen peroxide are identified as the principal mechanisms behind the observed enhancement in Mn(II) oxidation within algae-bacteria co-cultures. Our findings highlight the need to consider the effect of algae on microbial Mn(II) oxidation, which plays an important role in the environmental pollution remediation.

Effect of Biocides on the Activity of Extracellular Enzymes Produced by Degrader Fungi from Technical Objects Used in Tropical Climates (Vietnam).

Activity of extracellular enzymes was assessed in 20 strains of microscopic fungi involved in biodegradation of technical objects exploited under tropical climate conditions (Vietnam). It was found that 19strains possessed catalase activity, 18 strains had phenol oxidase activity, and eight strains had protease activity. The effect of industrial biocides on the activity of these enzymes was also assessed. The biocides Bior-1, Bioneutral A 10, and Bioneutral A 101 were shown to inhibit the enzymatic activity to various extent. All biocides inhibited extracellular catalase activity in most fungal strains studied. The inhibition of protease and phenol oxidase activity of same test strains was less pronounced. The response to biocides varied at the strain level; its characteristics could differ significantly even between strains of the same species. In several cases, it was observed that exposure to biocides resulted in an increase in enzyme activity.

Targeted intracellular catalase delivery protects neonatal rat myocytes from hypoxia-reoxygenation and ischemia-reperfusion injury

Hypoxia followed by reoxygenation and ischemia reperfusion cause cell death in neonatal rat ventricular myocytes primarily through the generation of oxidative stress. Extracellular catalase has not been effective in reducing or eliminating ischemia reperfusion- or hypoxia-reoxygenation-induced cell death due both to extracellular degradation and to poor cellular uptake. (1) To determine whether a cell-penetrating catalase derivative with enhanced peroxisome targeting efficiency (catalase-SKL) increases intracellular levels of the antioxidant enzyme in neonatal rat ventricular myocytes; and (2) to determine whether catalase-SKL protects against both hypoxia-reoxygenation and ischemia reperfusion injury. Neonatal rat ventricular myocytes were subjected to 3 or 6 h of hypoxia-reoxygenation or to 1 h of ischemia reperfusion. Extracellular catalase concentration, activity, and subcellular distribution were determined using standard techniques. Reactive oxygen species and related oxidative stress were visualized using 2',7'-dichlorofluorescin diacetate. Cell death was measured using trypan blue exclusion or lactate dehydrogenase release assays. Extracellular catalase activity was higher in (catalase-SKL) transduced myocytes, was concentrated in a membranous cellular fraction, and potently inhibited oxidative stress. In contrast to nontransducible (unmodified) extracellular catalase, catalase-SKL-treated myocytes were protected against both hypoxia-reoxygenation and ischemia reperfusion. (1) Catalase-SKL increased myocyte extracellular catalase content and activity and dramatically increased resistance to hydrogen peroxide-induced oxidation; (2) catalase-SKL protects against both hypoxia-reoxygenation and ischemia reperfusion; (3) catalase-SKL may represent a new therapeutic approach to protect hearts against myocardial hypoxia-reoxygenation or ischemia reperfusion.

Effects of Leucine-enkephalin on Catalase Activity and Hydrogen Peroxide Levels in the Haemolymph of the Pacific Oyster (Crassostrea gigas)

The nervous and immune systems of invertebrates can exchange information through neuropeptides. Furthermore, some opioid peptides can function as endogenous immune system messengers and participate in the regulation of the immune responses. The present study was designed to investigate the effects of leucine-enkephalin (L-ENK) on the activity of catalase (CAT) and hydrogen peroxide (H2O2) content in the haemolymph of the Pacific Oyster (Crassostrea gigas). The CAT activity and H2O2 content were investigated after the haemolymph of the species was exposed to 1, 5, and 50 μg/mL of L-ENK. The results indicate that the intracellular and extracellular CAT activity was increased with increasing concentration of L-ENK, while the intracellular and extracellular H2O2 content was decreased with increasing concentration of L-ENK. L-ENK may regulate the intracellular and extracellular CAT activity and H2O2 content via binding with opioid neuropeptide receptors on immunocytes of the oysters. The data strongly suggests an involvement of opioid peptides in the regulation of the antioxidant defence systems of Crassostrea gigas.

Extracellular catalase activity protects cysteine cathepsins from inactivation by hydrogen peroxide

The resistance of secreted cysteine cathepsins to peroxide inactivation was evaluated using as model THP-1 cells. Differentiated cells released mostly cathepsin B, but also cathepsins H, K, and L, with a maximum of endopeptidase activity at day 6. Addition of non-cytotoxic concentrations of H 2O 2 did not affect mRNA expression levels and activity of cathepsins, while the catalase activity remained also unchanged, consistently with RT-PCR analysis. Conversely inhibition of extracellular catalase led to a striking inactivation of secreted cysteine cathepsins by H 2O 2. This report suggests that catalase may participate in the protection of extracellular cysteine proteases against peroxidation.

Effects of Leucine-enkephalin on Catalase Activity and Glutathione Level in Haemolymph of the Scallop Chlamys farreri

The study was designed to determine whether leucine-enkephalin (L-ENK) and delta receptor were present on the haemocytes of the scallop Chlamys farreri, and investigate the effects of L-ENK on the activity of catalase (CAT) and glutathione (GSH) level in haemolymph of the scallop. Lots of haemocytes immunoreactive to anti-L-ENK and -delta receptor sera were observed. The CAT activity and GSH level were investigated after 1, 5, and 50 μg/ml of L-ENK were added into the haemolymph of the scallop C. farreri. The CAT activity in haemocyte lysate supernatant (HLS) and supernatant were enhanced with increasing concentration of L-ENK. It was also found that the resultant HLS and supernatant GSH content was induced by L-ENK. Both the resultant HLS and supernatant CAT activity and GSH content was highest when the concentration of L-ENK was 50 μg/ml. By binding with opioid neuropeptide receptors, the opioid neuropeptides can regulate the intracellular and extracellular CAT activity and GSH content. Overall, the data strongly suggests an involvement of opioid peptides in the regulation and improvement of the antioxidant defence systems of the scallop C. farreri.

Enhanced antioxidant defense due to extracellular catalase activity in Syrian hamster during arousal from hibernation

Mammalian hibernators are considered a natural model for resistance to ischemia–reperfusion injuries, and protective mechanisms against oxidative stress evoked by repeated hibernation-arousal cycles in these animals are increasingly the focus of experimental investigation. Here we show that extracellular catalase activity provides protection against oxidative stress during arousal from hibernation in Syrian hamster. To examine the serum antioxidant defense system, we first assessed the hibernation-arousal state-dependent change in serum attenuation of cytotoxicity induced by hydrogen peroxide. Serum obtained from hamsters during arousal from hibernation at a rectal temperature of 32 °C, concomitant with the period of increased oxidative stress, attenuated the cytotoxicity four-fold more effectively than serum from cenothermic control hamsters. Serum catalase activity significantly increased during arousal, whereas glutathione peroxidase activity decreased by 50%, compared with cenothermic controls. The cytoprotective effect of purified catalase at the concentration found in serum was also confirmed in a hydrogen peroxide-induced cytotoxicity model. Moreover, inhibition of catalase by aminotriazole led to an 80% loss of serum hydrogen peroxide scavenging activity. These results suggest that extracellular catalase is effective for protecting hibernators from oxidative stress evoked by arousal from hibernation.

Catalase activity in macro- and microorganisms as an indicator of biotic stress in coastal waters of the eastern Mediterranean Sea

In this study we examined the activity of catalase in the water column (mainly attributed to planktonic microorganisms) and the activity of catalase and superoxide dismutase (SOD), as well as lipid peroxidation in the midgut gland of the benthic bivalve Donax trunculus as possible indicators of biotic stress. The measurements were performed at stations situated at known contaminated and clean sites in the coastal waters and shores along the Israeli coast (eastern Mediterranean Sea). In the water column, we found that catalase activity was higher in polluted coastal waters than in nearby unpolluted or less-polluted stations. Moreover, there was diurnal periodicity in catalase activity rates which matched the diurnal changes in hydrogen peroxide levels in seawater. Consistent evidence of extracellular catalase activity was found in the seawater sampled. Catalase activity rates in the midgut gland of D. trunculus did not exhibit clear patterns with respect to site (polluted or clean) or season. However, SOD activity and lipid peroxidation measured in the same tissues were good indicators of organic pollution in the coastal waters examined and, among the three stations examined in Haifa Bay, Qiriat Haim was the most polluted.

Optimization of catalase biosynthesis in submerged cultures of Aspergillus niger mutant.

The effect of some medium components, viscous substances and metabolic inhibitors, on catalase production by mutant Aspergillus niger has been studied in shake culture. Altering the composition of the basal medium, particularly substituting NaNO3 for KNO3, and peptone for yeast extract brought an increase in extra- and intracellular catalase activity by 1.5- and 3-fold, respectively. The addition of 2.0-6.0 mg sodium alginate or pectin/ml as viscous additive to the medium, containing glucose as carbon source, increased the medium viscosity and catalase production in shake culture by about 2.8- to 3.0-fold. The highest yield of extracellular catalase activity of A. niger was obtained in the presence of sodium orthovanadate and Triton X-100, which improved the activity of this enzyme by about 1.5-2.2-fold. A significant increase in intracellular catalase activity was observed in the presence of hematin, Tween 80 and sodium orthovanadate (1.7-, 1.6- and 1.4-fold respectively). The time course of growth and enzyme production by A. niger in the optimized medium is also reported.