Induction Of Catalase Activity Research Articles

In Vivo Antioxidant Activity of Common Dietary Flavonoids: Insights from the Yeast Model Saccharomyces cerevisiae.

Oxidative stress, associated with diseases and aging, underscores the therapeutic potential of natural antioxidants. Flavonoids, known for scavenging free radicals and modulating cell signaling, offer significant health benefits and contribute to longevity. To explore their in vivo effects, we investigated the antioxidant activity of quercetin, apigenin, luteolin, naringenin, and genistein, using Saccharomyces cerevisiae as a model organism. We performed viability assays to evaluate the effects of these compounds on cell growth, both in the presence and absence of H2O2. Additional assays, including spot assays, drug drop tests, and colony-forming unit assays, were also conducted. Viability assays indicated that the tested compounds are non-toxic. H2O2 reduced yeast viability, but flavonoid-treated cells showed increased resistance, confirming their protective effect. Polyphenols scavenged intracellular reactive oxygen species (ROS) and protected cells from oxidative damage. Investigations into defense systems revealed that H2O2 induced catalase activity and oxidized glutathione accumulation, both of which were reduced by polyphenol treatment. The tested natural compounds enhance cell viability and reduce oxidative damage by scavenging ROS and modulating antioxidant defenses. These results suggest their potential as supplements and pave the way for further research.

Catalase associated with antagonistic changes of abscisic acid and gibberellin response, biosynthesis and catabolism is involved in eugenol-inhibited seed germination in rice.

The inhibitory effect of eugenol on rice germination is mediated by a two-step modulatory process: Eugenol first regulates the antagonism of GA and ABA, followed by activation of catalase activity. The natural monoterpene eugenol has been reported to inhibit preharvest sprouting in rice. However, the inhibitory mechanism remains obscure. In this study, simultaneous monitoring of GA and ABA responses by thein vivoGA and ABA-responsive dual-luciferase reporter system showed that eugenol strongly inhibited the GA response after 6h of imbibition, whereas eugenol significantly enhanced the ABA response after 12h of imbibition. Gene expression analysis revealed that eugenol significantly induced the ABA biosynthetic genes OsNCED2, OsNCED3, and OsNCED5, but notably suppressed the ABA catabolic genes OsABA8ox1 and OsABA8ox2. Conversely, eugenol inhibited the GA biosynthetic genes OsGA3ox2 and OsGA20ox4 but significantly induced the GA catabolic genes OsGA2ox1 and OsGA2ox3 during imbibition.OsABI4,the key signaling regulator of ABA and GA antagonism, was notably induced before 12h and suppressed after 24h by eugenol. Moreover, eugenol markedly reduced the accumulation of H2O2in seeds after 36h of imbibition. Further analysis showed that eugenol strongly induced catalase activity, protein accumulation, and the expression of three catalase genes. Most importantly, mitigation of eugenol-inhibited seed germination was found in thecatcmutant. These findings indicate that catalase associated with antagonistic changes of ABA and GA is involved in the sequential regulation of eugenol-inhibited seed germination in rice.

Toxicological approaches as tool to assess the effects of a mixture of photocatalytic degradation products originated from the unregulated neonicotinoid acetamiprid employing a terrestrial organism (Eisenia andrei)

Acetamiprid (ACT) has been detected in several water sources in Latin America. The presence of its degradation products in the environment is not negligible and transformation products (TPs) significantly contribute to environmental health risks. Although advanced oxidative processes are promising for the treatment of this neocotinoid, effects of these are still unknown. In this context, the effects of a mixture of photocatalytic degradation products resulting from an ACT treatment for 90 min employing TiO2/UV on cytotoxicity and oxidative stress parameters in Eisenia andrei earthworms in acute and chronic experiments using typical Latin American soil were assessed. Acute contact tests were performed (72 h) using a filter paper moistened with an ACT solution and a chronic test was performed using Oxisoil (200 g) moistened with an ACT solution for 45 days. Catalase (CAT) and glutathione-S-transferase (GST) activities, reduced glutathione (GSH) levels and cytotoxicity (cellular eleocyte and amoebocyte assessments) were investigated. Over 75 % of ACT was degraded within the first 15 min of treatment, with levels below the limit of detection after 60 min. The acute test revealed greater cytotoxic effects associated with the effluents treated for T0 and T15 min, with decreased cell density noted after 48 h of exposure, in addition to CAT induction (in all treatments) and GST induction following T0, T15 and T90 min exposures. Concerning the chronic assay, decreases in cell density (T0, T15, T60 and T90 min) and viability (T0, T60 and T90 min) were observed after 45 days, in addition to induced CAT activity following T0, T15 and T60 exposures and GST induction following the T60 min exposure. Reduced glutathione levels were unaltered, comprising the least sensitive biomarker among the investigated parameters to the treated effluent exposures. The mixture of ACT degradation products can cause toxic effects to non-target organisms, despite parent compound degradation, alerting for the need for ecotoxicological tests to prove decreased effluent toxicity, in addition to the improvement of degradation techniques.

Physiological roles of catalases Cat1 and Cat2 in Myxococcus xanthus.

Catalases are key antioxidant enzymes in aerobic organisms. Myxococcus xanthus expresses two monofunctional catalases, small-subunit Cat1 and large-subunit Cat2. The Km of H2O2 for recombinant Cat1 and Cat2 were 14.0 and 9.0 mM, respectively, and the catalytic efficiency of Cat2 (kcat/Km = 500 sec-1 mM-1) was 4-fold higher than that of Cat1. The activity ratio of Cat1 to Cat2 in the exponential growth phase of M. xanthus was 1 to 3-4. A Cat1-deficient strain was constructed, whereas a Cat2-deficient strain could not be produced In H2O2-supplemented medium, the cat1 mutant exhibited marked growth retardation and a longer generation time than the wild-type (wt) strain. After 2 h of incubation in 0.5 mM H2O2-supplemented medium, the catalase activity of the wt strain significantly increased (by 64-fold), but that of the cat1 mutant strain did not. Under starvation-induced developmental conditions, catalase activity was induced by approximately 200-fold in both wt and cat1 strains, although in the mutant the activity increase as well as spore formation occurred one day later, indicating that the induction of catalase activity during starvation was due to Cat2. In wt starved cells, catalase activity was not induced by H2O2. These results suggest that Cat2 is the primary housekeeping catalase during M. xanthus growth and starvation-induced development, whereas Cat1 may have a complementary role, being responsible for the rapid degradation of H2O2 in proliferating vegetative cells subjected to oxidative stress.

Oxidative stress and histological changes caused by lambda-cyhalothrin on the snail Helix aspersa

This study was interested in evaluating the toxicity of an insecticide based on lambda-cyhalothrin, newly approved and widely used in agriculture in Algeria, on an alternativebiological model, the snail Helix aspersa.In order to achieve these objectives, we based our-selves on the evaluation of the degree of oxidative stress by monitoring the average weightof the snails, the level of total proteins and Glutathione-SH (GSH), as well as the enzymaticactivities of Glutathione S-transferase (GST ) and Catalase activity (CAT ) at the level ofthe hepatopancreas. We performed a histopathological examination of the kidney and hep-atopancreas.The results show that lambda-cyhalothrin causes a dose-dependent decreasein the average weight of snails, an increase in the content of total proteins, and a decrease inthe level of GSH , in parallel with the induction of GST activities and CAT. Histopathologicalexamination conirmed the toxicity of lambda-cyhalothrin in Helix aspersa.

Effects of one-dimensional nanomaterial polyaniline nanorods on earthworm biomarkers and soil enzymes.

Polyaniline nanorods (PANRs) are typical one-dimensional nanomaterials (1D NMs), which are widely used in medicine, batteries and water treatment, etc. Applications of PANRs will eventually enter the soil environment, but their ecotoxicity has been barely reported. Therefore, we measured earthworm biomass, earthworm biomarkers and soil enzymes to investigate the ecotoxicity of PANRs. The result of positive and increasing growth inhibition rates (GIR) showed that PANRs inhibited earthworm growth. As for earthworm biomarkers, PANRs caused a decrease in protein content, indicating that PANRs stress would increase earthworm energy consumption. Except for the 7th day, the activities of SOD, CAT and POD consistently increased, suggesting that PANRs activated the earthworm antioxidant system. The continually augment of MDA content indicated that PANRs stress would cause earthworm lipid damage. Na+-K+-ATPase increased with an excellent dose-time relationship. Differently, cellulase and AChE activities promoted at low concentrations and inhibited at high concentrations. The positive and dose-dependent IBRv2 indicated that the higher the concentrations of PANRs, the greater the ecotoxicity to earthworms. PANRs inhibited the soil enzyme activities such as sucrase, neutral phosphatase, protease and urease, while induced catalase activity in a dose-dependent manner. Earthworm addition reduced catalase activity by 10.74-29.99%, but improved other soil enzymes activities, demonstrating that earthworms played a positive role in regulating soil enzyme activity. GMean and T-SQI consistently increased due to earthworm activity, meaning a higher soil microbial functional diversity. Generally, this study provided data support for future PANRs toxicity studies, but their toxicity mechanisms still need to be further studied.

Medicinal Plants Extracts Impact on Oxidative Stress in Mice Brain Under the Physiological Conditions: the Effects of Corn Silk, Parsley, and Bearberry.

This study was performed to examine the effects of medicinal plant extracts of corn silk (Stigma maydis), parsley leaf (Petroselini folium), and bearberry leaf (Uvae ursi folium) on antioxidant status of the brain of experimental animals (mice) under the physiological conditions. Biological properties of these plants are insufficiently investigated and the aim was to explore their possible antioxidant effects that can alleviate oxidative damage of the brain tissue. Corn silk extract showed positive effect on activities of antioxidant enzymes in mice brain tissue. Parsley extract induced the increase in glutathione content and decrease of lipid peroxidation. Bearberry leaf extract induced catalase activity and decrease of hydroxyl radical content, while malonyldialdehide accumulation was maintained at the control level. Results obtained in this study support the use of corn silk, parsley and bearberry leaves as natural antioxidant sources in the prevention and treatment of brain tissue damages and different diseases caused by oxidative stress.

The Onset of Tacrolimus Biosynthesis in Streptomyces tsukubaensis Is Dependent on the Intracellular Redox Status.

The oxidative stress response is a key mechanism that microorganisms have to adapt to changeling environmental conditions. Adaptation is achieved by a fine-tuned molecular response that extends its influence to primary and secondary metabolism. In the past, the role of the intracellular redox status in the biosynthesis of tacrolimus in Streptomyces tsukubaensis has been briefly acknowledged. Here, we investigate the impact of the oxidative stress response on tacrolimus biosynthesis in S. tsukubaensis. Physiological characterization of S. tsukubaensis showed that the onset of tacrolimus biosynthesis coincided with the induction of catalase activity. In addition, tacrolimus displays antioxidant properties and thus a controlled redox environment would be beneficial for its biosynthesis. In addition, S. tsukubaensis ∆ahpC strain, a strain defective in the H2O2-scavenging enzyme AhpC, showed increased production of tacrolimus. Proteomic and transcriptomic studies revealed that the tacrolimus over-production phenotype was correlated with a metabolic rewiring leading to increased availability of tacrolimus biosynthetic precursors. Altogether, our results suggest that the carbon source, mainly used for cell growth, can trigger the production of tacrolimus by modulating the oxidative metabolism to favour a low oxidizing intracellular environment and redirecting the metabolic flux towards the increase availability of biosynthetic precursors.

Transcriptional Profiling of Catalase Genes in Juglone-Treated Seeds of Maize (Zea Mays L.) and Wheat (Triticum Aestivum L.)

The major aim of the present study was to investigate the influence of juglone (JU; 5-hydroxy-l,4-naph-thoquinone) treatments on the expression level of Catl, Cat2 and Cat3 genes, encoding the respective catalase isozymes in maize (Zeamays L.) and wheat (Triticum aestivum L.) seeds. In parallel, germination efficiency, catalase (CAT) activity and hydrogen peroxide (H2O2) content in juglone-exposed cereal seeds were assessed. Juglone applications significantly stimulated abundance of three target catalase transcripts as well as induced CAT activity and generation of H2O2 in both maize and wheat kernels. Furthermore, germination process of juglone-affected maize seeds was more severe suppressed than in case of wheat kernels. The role of juglone in triggering the oxidative stress as well as antioxidative responses in seeds of the studied model cereal species are discussed.

Cross-talk between physiological and biochemical adjustments by Punica granatum cv. Dente di cavallo mitigates the effects of salinity and ozone stress

Plants are exposed to a broad range of environmental stresses, such as salinity and ozone (O3), and survive due to their ability to adjust their metabolism. The aim of this study was to evaluate the physiological and biochemical adjustments adopted by pomegranate (Punica granatum L. cv. Dente di cavallo) under realistic field conditions. One-year-old saplings were exposed to O3 [two levels denoted as ambient (AO) and elevated (EO) O3 concentrations] and salinity [S (salt, 50 mM NaCl)] for three consecutive months. No salt (NS) plants received distilled water. Despite the accumulation of Na+ and Cl− in the aboveground biomass, no evidence of visible injury due to salt (e.g. tip yellow-brown lesions) was found. The maintenance of leaf water status (i.e. unchanged values of electrolytic leakage and relative water content), the significant increase of abscisic acid, proline and starch content (+98, +65 and +59% compared to AO_NS) and stomatal closure (−24%) are suggested to act as adaptive mechanisms against salt stress in AO_S plants. By contrast, EO_NS plants were unable to protect cells against the negative impact of O3, as confirmed by the reduction of the CO2 assimilation rate (−21%), accumulation of reactive oxygen species (+10 and +225% of superoxide anion and hydrogen peroxide) and malondialdehyde by-product (about 2-fold higher than AO_NS). Plants tried to preserve themselves from further oxidative damage by adopting some biochemical adjustments [i.e. increase in proline content (+41%) and induction of catalase activity (8-fold higher than in AO_NS)]. The interaction of the two stressors induced responses considerably different to those observed when each stressor was applied independently. An analysis of the antioxidant pool revealed that the biochemical adjustments adopted by P. granatum under EO_S conditions (e.g. reduction of total ascorbate; increased activities of superoxide dismutase and catalase) were not sufficient to ameliorate the O3-induced oxidative stress.

Ferulic acid confers tolerance against excess boron by regulating ROS levels and inducing antioxidant system in wheat leaves (Triticum aestivum)

Ferulic acid (FA; 3-methoxy-4-hydroxycinnamic acid) is a candidate for improving plant tolerance to stress conditions through improving water solubility and antioxidant activity. To our knowledge, no study has thus far explored the potential for exogenous FA application to improve tolerance against excess boron (B) in plants. For this purpose, wheat seedlings grown in hydroponic culture were treated with FA (25 and 75 μM) alone or in combination with B (4 and 8 mM). The results showed that B caused a decrease in water content (RWC), osmotic potential (ΨΠ) and proline content (Pro). FA application prevented decreases of these parameters. 8 mM B increased superoxide dismutase (SOD) activity. Superoxide anion radical (O2―) and hydrogen peroxide (H2O2) increased during B exposure, while catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX) and glutathione reductase (GR) activities did not. However, due to increased SOD activity, FA under stress successfully decreased O2― content. Additionally, exogenously applied FA under 4 mM B stress increased the activities of CAT and POX. While excess B in wheat leaves did not induce activities of APX, GR, monodehydroascorbate reductase (MDHAR) or dehydroascorbate reductase (DHAR) or increase total ascorbate (tAsA) or dehydroascorbate (DHA) contents, FA with stress did. 25 μM FA with B remarkably maintained regeneration of ascorbate and induced contents of tAsA and GSH (including the ascorbate-glutathione cycle) and induced CAT activity. Taken together, stress-induced H2O2 content significantly decreased and the scavenging of OH increased in wheat with FA application through the activation of antioxidant enzymes. Consequently, FA prevented lipid peroxidation (TBARS) caused by stress due to increased radical scavenging activity.

External spermine prevents UVA-induced damage of Synechocystis sp. PCC 6803 via increased catalase activity and decreased H2O2 and malonaldehyde levels

Common polyamines, putrescine (Put), spermidine (Spd), and spermine (Spm), are cationic compounds known as beneficial factors for many cellular processes including cell division, proliferation, differentiation, and stress response in all living organisms. Effects of exogenous Spm on the protective responses of Synechocystis sp. PCC 6803 exposed to UVA were investigated. The presence of 0.5 mM Spm in the culture medium significantly reduced cell growth after 60 min under white light condition but protected the cells after growing for 60 min under UVA. The stress-tolerant response of Synechocystis cells represented by the ratio of putrescine/spermidine (Put/Spd) showed about a 6-fold increase after 60 min UVA in the presence of Spm. In addition, those levels of chlorophyll a, carotenoids, and photosynthetic oxygen evolution were increased by Spm supplementation in UVA-treated cells. Exogenous Spm induced the activity of catalase but not superoxide dismutase in cells under UVA treatment. On the other hand, Spm treatment enabled cells to apparently decrease the intracellular free radical H2O2 and malonaldehyde (MDA) levels. Overall results suggested that Spm supplementation could protect Synechocystis sp. PCC 6803 cells via the increase of Put/Spd ratio and the reduction of both H2O2 and MDA levels in conjunction with the induction of catalase activity. Interestingly, UVA-treated cells as compared to non-treated cells with exogenous Spm showed a decrease of Spm with an increase of Put and no change in Spd. This suggested the back conversion of Spm to Spd and finally to Put as cellular mechanism in response to UVA.

Multicellular behavior of environmental Escherichia coli isolates grown under nutrient-poor and low-temperature conditions

The multicellular behavior designated “red dry and rough” (rdar) morphotype—characterized by production of extracellular matrix mainly comprising curli fimbriae and cellulose—is a potential survival strategy of Escherichia coli outside the host. This study documents the ability of Escherichia cryptic clades, which have recently been recognized as new lineages genetically divergent from E. coli, to grow in unfavorable conditions through expression of distinct phenotypes. Growth under low-temperature and nutrient-poor conditions induced the rdar morphotype in all cryptic clade strains tested, especially after preincubation in broth supplemented with uracil. Such phenotypic response to harsh growth conditions was clearly detected by transmission and scanning electron microscopy, which showed that bacteria were encased in a fibrous matrix. Conversely, cells incubated in rich medium at 37 °C showed no matrix. Uracil enhanced the biosynthesis of matrix components, fostering biofilm production and strain adhesion to abiotic surfaces, as demonstrated by the increase of strong biofilm producers in biofilm assays. Harsh growth conditions also induced catalase activity, resulting in clade strain resistance to hydrogen peroxide oxidative stress. The present findings further support the ‘environmental hypothesis’ whereby cryptic clades would be able to persist in natural habitats outside the host through the expression of distinct survival phenotypes.

Uptake and biological responses in land snail Cornu aspersum exposed to vaporized CdCl2

The uptake of Cd and some biomarkers of exposure and effects have been investigated in specimens of land snail Cornu aspersum exposed to vaporized CdCl2 (10mg/L) for 7 days. The Cd levels quantified in snail's whole bodies confirmed Cd bioavailability trough vaporization and an higher accumulation in the midgut gland compared to the foot. Biological responses investigated showed a reduction of destabilization time of lysosomal membranes (NRRT) in hemocytes and an induction of catalase activities (CAT) in midgut gland. A further evidence of CdCl2 vaporized exposure was given by an increase in MT protein content as well as induction of Cd-MT gene expression, highlighting the central role of the midgut gland in Cd detoxification. These biomarkers can thus be considered as sensitive tools for the assessment of Cd contamination in the air using land snails as bioindicators. No changes in of GST activity and MDA were observed. From the overall results, the land snail, C. aspersum, could be used as good bioindicator of air quality for pollution monitoring purposes having shown clear signs of exposure and effects due Cd exposure by air.

Mixtures of diflubenzuron and p-chloroaniline changes the activities of enzymes biomarkers on tilapia fish (Oreochromis niloticus) in the presence and absence of soil

The insecticide Diflubenzuron (DFB), used by many fish farming, when metabolized or degraded produces the extremely toxic compound p-chloroaniline (PCA). Once in the aquatic environment, these compounds can form mixtures and their bioavailability depends on factors such as the presence of soil. The toxic effects of the isolated compounds and their mixtures in the proportions: 75%, 50%, and 25% of PCA were analyzed in tilapia (Oreochromis niloticus) in the presence and absence of soil after 96h. The enzymes catalase (CAT), acid (AcP) and alkaline (AlP) phosphatases and alanine (ALT) and aspartate (AST) aminotransferases of the liver of the tilapia (Oreochromis niloticus) were used as biomarkers. DFB and the mixture containing 75% of this compound did not present high toxicity to fish; however, 25mg/L of PCA alone and 15mg/L of the mixture with 75% of this compound promoted 50% mortality of tilapia (Oreochromis niloticus). In the presence of soil, these toxicity values decreased to 37 and 25mg/L, respectively. Independent of the presence of soil, a synergistic effect was observed when the proportion of PCA was 75% and to the mixture, with 25% PCA was observed the antagonistic effect. Different concentrations of the compounds and their mixtures induced CAT activity independently of the presence of soil. Additionally, increases in phosphatases and transaminases activities were observed. In some cases, the enzymes also had their activities decreased and the dose-dependence effects were not observed. This research showed that the presence of soil influenced the toxicity of the compounds but not altered interaction type among them. Diflubenzuron, p-chloroaniline, and mixtures thereof caused disorders in enzymes important for the health of tilapia (Oreochromis niloticus).

SALICYLIC ACID IMMERSION MAINTAINS PHYSIOCHEMICAL QUALITY AND ENHANCES BIOACTIVE COMPOUNDS IN ‘KIMJU’ GUAVA FRUIT DURING COLD STORAGE

The aims of this work were to investigate the effect of salicylic acid (SA) immersion on the physicochemical quality maintenance and biologically active compounds enhancement of ’Kimju’ guava. The fruit were immersed in water (control) and 2 mM SA solution and stored at 12 ± 1 ºC, 90±2% RH. The observed factors were pigments, total sugars, total soluble solids (TSS), total acidity (TA), firmness and pectin components, bioactive compounds such as ascorbic acid (AsA), total phenols (TP), total flavonoids (TF) and the activities of antioxidant enzymes including peroxidase (POD) and catalase (CAT). The total chlorophylls chlorophyll a and b contents of the treated fruit were higher than those of the control. The SA immersion did not affect the total carotenoids concentration and TSS whilst it delayed the increase in total sugars and lowered TA content. The fruit softening was delayed by the SA immersion due to the control of soluble pectin increase and insoluble pectin decrease. The antioxidant activity and the concentrations of AsA, TP and TF were enhanced by the SA immersion. The SA immersion also stimulated POD activity but did not induced CAT activity. In conclusion, 2.0 mM SA immersion is an effective postharvest treatment maintaining quality and improving nutritional values of ‘Kimju’ guava.

Antioxidant Enzyme Responses Induced by Whiteflies in Tobacco Plants in Defense against Aphids: Catalase May Play a Dominant Role.

BackgroundBemisia tabaci MEAM1 (Middle East-Asia Minor 1) feeding alters antioxidative enzyme activity in some plant species. Infestation of B. tabaci nymphs decreases Myzus persicae performance on systemic, but not local leaves of tobacco plants. However, it is unclear if B. tabaci nymphs induced antioxidant activities contributing to the aphid resistance.Methodology/Principal FindingsWe investigated the relationship between antioxidants induced by nymphs of B. tabaci feeding on tobacco and aphid resistance. The activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and the concentration of hydrogen peroxide (H2O2) were assayed in tobacco leaves at different feeding times following infestation of B. tabaci nymphs. The infestation altered the activities of CAT and POD, but had no significant effect on SOD activity. The highest CAT activity was observed at 15 d after infestation. This was 98.2% greater than control systemic leaves, but 32.6% lower than the control in local leaves. Higher POD activity was recorded in local vs. systemic leaves after 15 d of infestation. POD activity was 71.0% and 112.9% higher in local and systemic leaves, respectively, than in the controls. The changes of CAT, but not POD or SOD activity were correlated to levels of aphid resistance. H2O2 levels were higher in local than in systemic leaves in contrast to CAT activity. Tobacco curly shoot virus mediated virus-induced gene silencing was employed to determine if CAT activation was involved in the aphid resistance induced by B. tabaci nymphs. B. tabaci induced CAT activity decreased when the Cat1 expression was silenced. The performance assay indicated that Cat1 silencing made B. tabaci infested plants a more suitable host for aphids than infested control plants. The aphid survival rate was reduced by 40.4% in infested control plants, but reduced by only 26.1% in Cat1-silenced plants compared to uninfested controls. Also, qPCR results showed that silencing of Cat1 led to the suppression of the B. tabaci mediated PR-2a expression.Conclusions/SignificanceAphid resistance in plants infested with B. tabaci nymphs is associated with enhanced antioxidant activities in which CAT may play a dominant role. This resistance probably acted via interactions with SA-mediated defense responses.

Omega-3 fatty acids differentially modulate enzymatic anti-oxidant systems in skeletal muscle cells.

During physical activity, increased reactive oxygen species production occurs, which can lead to cell damage and in a decline of individual's performance and health. The use of omega-3 polyunsaturated fatty acids as a supplement to protect the immune system has been increasing; however, their possible benefit to the anti-oxidant system is not well described. Thus, the aim of this study was to evaluate whether the omega-3 fatty acids (docosahexaenoic acid and eicosapentaenoic acid) can be beneficial to the anti-oxidant system in cultured skeletal muscle cells. C2C12 myocytes were differentiated and treated with either eicosapentaenoic acid or docosahexaenoic acid for 24h. Superoxide content was quantified using the dihydroethidine oxidation method and superoxide dismutase, catalase, and glutathione peroxidase activity, and expression was quantified. We observed that the docosahexaenoic fatty acids caused an increase in superoxide production. Eicosapentaenoic acid induced catalase activity, while docosahexaenoic acid suppressed superoxide dismutase activity. In addition, we found an increased protein expression of the total manganese superoxide dismutase and catalase enzymes when cells were treated with eicosapentaenoic acid. Taken together, these data indicate that the use of eicosapentaenoic acid may present both acute and chronic benefits; however, the treatment with DHA may not be beneficial to muscle cells.

Thermal Water from Uriage-les-Bains Exerts DNA Protection, Induction of Catalase Activity and Claudin-6 Expression on UV Irradiated Human Skin in Addition to Its Own Antioxidant Properties

Aim: In order to decipher the mechanisms underlying the known protective effects of the thermal water from Uriage-les-Bains (TWFULB) on the skin barrier function, we studied its antioxidant properties as well as its effect on the expression of the tight-junctional protein claudin-6, a candidate tumor suppressor factor. Study Design/Methods: In a first step, TBARS and SOD activity assays were performed in an in vitro model of human dermal fibroblasts treated by hypoxanthine/xanthine oxidase (HO/XO) mixture, in order to evaluate the own antioxidant effect of the thermal water. In a second step, human keratinocytes irradiated or not by UVB were used to evaluate the protective role of TWFULB on nuclear DNA damage using a comet assay. In a third step, an ex vivo model of human skin explants irradiated or not by UVA and UVB was used to evaluate the effect of TWFULB on the intracellular catalase activity and on the cutaneous claudin-6 expression. Results: TWFULB showed significant protective effects against oxidative stress induced by HO/XO: the cell viability was improved and the lipid peroxidation was reduced. The tested thermal water also showed significant SOD-like activity and protective effect on the UVB-stressed DNA. Considering the ex vivo models of skin explants, TWFULB was able to counterbalance the “negative” effect of UVB on the intracellular catalase activity and on the cutaneous claudin-6 expression.Conclusion: This multiparametric approach shows the antioxidant activity of TWFULB and emphasizes its role in the DNA protection of the cutaneous tissue in front of the UV irradiations, and finally suggests that some effects could involve the candidate suppressor functions of claudin-6.

Enzymatic biomarkers as tools to assess environmental quality: A case study of exposure of the honeybee Apis mellifera to insecticides

The present study was intended to evaluate the responses of enzymes in the honeybee Apis mellifera after exposure to deltamethrin, fipronil, and spinosad and their use as biomarkers. After determination of the median lethal doses (LD50), honeybees were exposed at doses of 5.07 ng/bee and 2.53 ng/bee for deltamethrin, 0.58 ng/bee and 0.29 ng/bee for fipronil, and 4.71 ng/bee and 2.36 ng/bee for spinosad (equivalent to 1/10th [LD50/10] and 1/20th [LD50/20] of the LD50, respectively). The responses of acetylcholinesterase (AChE), carboxylesterases (CaEs-1-3), glutathione-S-transferase (GST), catalase (CAT), and alkaline phosphatase (ALP) were assessed. The results showed that deltamethrin, fipronil, and spinosad modulated these biomarkers differentially. For the enzyme involved in the defense against oxidative stress, fipronil and spinosad induced CAT activity. For the remaining enzymes, 3 response profiles were identified. First, exposure to deltamethrin induced slight effects and modulated only CaE-1 and CaE-2, with opposite effects. Second, spinosad exhibited an induction profile for most of the biomarkers, except AChE. Third, fipronil did not modulate AChE, CaE-2, or GST, increased CAT and CaE-1, and decreased ALP. Thus, this set of honeybee biomarkers appears to be a promising tool to evaluate environmental and honeybee health, and it could generate fingerprints to characterize exposures to pesticides.