Selenium-dependent Glutathione Peroxidase Research Articles

Two variants of selenium-dependent glutathione peroxidase from the disk abalone Haliotis discus discus: Molecular characterization and immune responses to bacterial and viral stresses.

Glutathione peroxidase (GPx) is an essential member of the antioxidant systems of living organisms and may be involved in immune defense against pathogenic invasion. In the current study, two selenium-dependent glutathione peroxidases (AbSeGPxs) that shared 54.3% identity were identified from the disk abalone Haliotis discus discus. The open reading frames (ORFs) of AbSeGPx-a and AbSeGPx-b coded for 222 and 220 amino acids, respectively, with a characteristic selenocysteine residue encoded by an opal stop codon (TGA). The conserved selenocysteine insertion sequence (SECIS) element was predicted in the 3' untranslated region (UTR) of both isoforms, and they were found to form two stem-loop structures. Amino acid comparison and phylogenetic studies revealed that the AbSeGPxs were closely related to those in other mollusk species and were evolutionarily distinct from those of other taxonomic groups. The SYBR Green qPCR was employed in investigating the transcripts of AbSeGPxs. The expression of AbSeGPxs mRNA was examined in different embryonic developmental stages and differential expression patterns for AbSeGPx-a and AbSeGPx-b were noted. Meanwhile, the highest expression of AbSeGPxs was detected in the hepatopancreas of healthy adult animals. Next, transcriptional levels were profiled in hemocytes of adults to determine the immune responses of AbSeGPxs to microbial infections. The results revealed the significant up-regulation of AbSeGPx-a in a time-dependent manner after bacterial (Listeria monocytogenes and Vibrio parahaemolyticus) and viral (viral hemorrhagic septicemia virus) infections. Consequently, these findings indicate that AbSeGPx-a and AbSeGPx-b might be involved in the embryonic development of disk abalone and the regulation of immune defense system of adult animals.

Interaction between vitamin B6 and source of selenium on the response of the selenium-dependent glutathione peroxidase system to oxidative stress induced by oestrus in pubertal pig

This study aimed to assess the interaction between vitamin B6 and selenium (Se) for the flow of Se towards the Se-dependent glutathione peroxidase (GPX) system in response to oxidative stress naturally induced by oestrus in a pubertal pig model. At first oestrus, forty-five gilts were randomly assigned to the experimental diets (n=9/group): basal diet (CONT); CONT+0.3mg/kg of Na-selenite (MSeB60); MSeB60+10mg/kg of HCl-B6 (MSeB610); CONT+0.3mg/kg of Se-enriched yeast (OSeB60); and OSeB60+10mg/kg of HCl-B6 (OSeB610). Blood samples were collected at each oestrus (long-term profiles), and daily from day −4 to +3 (slaughter) of the fourth oestrus (peri-oestrus profiles) after which liver, kidneys, and ovaries were collected. For long-term profiles, CONT had lower blood Se than Se-supplemented gilts (p<0.01) and OSe was higher than MSe (p<0.01). Lower erythrocyte pyridoxal-5-phosphate was found in B60 than B610 (p<0.01). No treatment effect was observed on GPX activity. For peri-oestrus profiles, treatment effects were similar to long-term profiles. Treatment effects on liver Se were similar to those for long-term blood Se profiles and OSe had higher renal Se concentrations than MSe gilts (p<0.01). Gene expressions of GPX1, GPX3, GPX4, and selenocysteine lyase in liver and kidney were greatest in OSeB610 gilts (p<0.05). These results suggest that dietary B6 modulate the metabolic pathway of OSe towards the GPX system during the peri-oestrus period in pubertal pigs.

Evaluation of ecotoxicological effects of drugs on Daphnia magna using different enzymatic biomarkers

The increasing occurrence of pharmaceutical drugs in the aquatic environment is cause of concern, due to the possibility of toxic phenomena in non-target species, including oxidative stress and neurotoxicity. The present study aimed to assess the acute effect of four widely used therapeutic agents: acetaminophen (analgesic), chlorpromazine (antipsychotic), diclofenac (anti-inflammatory) and propranolol (antihypertensive), in the cladoceran species Daphnia magna. Considering the involvement of the mentioned compounds in the impairment of cholinesterasic activity and modifications in cellular redox systems, the purpose of this study was to analyze their effects on biomarkers of neuronal regulation, such as total cholinesterases (ChEs), and enzymatic oxidative stress defense, including as catalase (CAT), glutathione-S-transferases (GSTs), and total and selenium-dependent glutathione-peroxidase (total GPx; Se-GPx) activities. Exposure to acetaminophen caused a significant inhibition of AChE and Se-GPx activities in D. magna relative to the control. Among the biomarkers of oxidative stress, only the activity of CAT was significantly altered in concentration of 0.001mg L−1 of chlorpromazine, which was not always consistent with the literature. Diclofenac caused a significant inhibition of AChE and Se-dependent GPx, and also in total GPx activities. Propranolol was responsible for a significant decrease in the activity of the latter two enzymes, and also a slight increase of GSTs activity. The results indicated that the exposure to all the tested compounds induced alterations on the cellular redox status in the studied species. In addition, acetaminophen and diclofenac were shown to have the capability of interfering with D. magna neurotransmission, through the inhibition of ChEs. Our data enlighten the need for more research on the ecological consequences of pharmaceuticals in non-target organisms.

Decreased plasma thiol antioxidant barrier and selenoproteins as potential biomarkers for ongoing methylmercury intoxication and an individual protective capacity.

Manifestation of methylmercury (MeHg) toxicity depends on individual susceptibility to MeHg, as well as MeHg burden level. Therefore, biomarkers that reflect the protective capacity against MeHg are needed. The critical role of oxidative stress in the pathogenesis of MeHg cytotoxicity has been demonstrated. Because MeHg has high affinity for selenohydryl groups, sulfhydryl groups, and selenides, and causes posttranscriptional defects in selenoenzymes, proteins with selenohydryl and sulfhydryl groups should play a critical role in mediating MeHg-induced oxidative stress. Here, plasma oxidative stress markers and selenoproteins were investigated in MeHg-intoxicated rats showing neuropathological changes after 4 weeks of MeHg exposure. The thiol antioxidant barrier (-SHp) level significantly decreased 2 weeks after MeHg exposure, which is an early stage at which no systemic oxidative stress, histopathological changes, or clinical signs were detected. Diacron reactive oxidant metabolite (d-ROM) levels significantly increased 3 weeks after MeHg exposure, indicating the occurrence of systemic oxidative stress. Rats treated with lead acetate or cadmium chloride showed no changes in levels of -SHp and d-ROM. Selenoprotein P1 abundance significantly decreased in MeHg-treated rats, whereas it significantly increased in rats treated with Pb or Cd. Plasma selenium-dependent glutathione peroxidase (GPx3) activity also significantly decreased after MeHg exposure, whereas plasma non-selenoenzyme glutathione reductase activity significantly increased in MeHg-treated rats. The results suggest that decreased capacity of -SHp and selenoproteins (GPx3 and selenoprotein P) can be useful biomarkers of ongoing MeHg cytotoxicity and the individual protective capacity against the MeHg body burden.

Модуляция активности сопряженных систем no/глутатион в ишемизированном головном мозге экспериментальных животных препаратом «Селеназа» в различных дозах

The authors have identified priority units – target neuroprotective therapy aimed at restoring the ratio NO/glutathione restored. For this purpose, animals with acute cerebral blood flow (stroke) were injected modulator selenium-dependent glutathione peroxidase medicament &amp;#34;Selenaza&amp;#34; in various doses. In the experiment, the authors used the model of bilateral occlusion of the common carotid arteries – by type of ischemic stroke to Wistar rats. It has been shown that the administration of different dosages &amp;#34;Selenaza&amp;#34; significantly reduces stress marker nitrosating stress - nitrotyrosine, improves the reduced glutathione and glutathione peroxidase enzyme, modifies thiol-disulfide equilibrium in the direction of its reduced forms. According to effect – dose dependence, the concentrations of sodium selenite were calculated ED50 drug &amp;#34;Selenaza&amp;#34;, it was 50 ug/ml.&#x0D; Conclusions: These results suggest that selenium protects neurons against hypoxic/ischemic damage by reducing oxidative stress, restoring mitochondrial functional activities, as well as increase levels of reduced glutathione and glutathione peroxidase and reduce markers of nitrosating stress- nitrotyrosine.&#x0D;

Activity of antioxidant enzymes in the liver of wild boars (Sus scrofa) from aselenium-deficient area depending on sex, age, and season of the year

The aim of this study was to compare the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and total and selenium-dependent glutathione peroxidase (total GSH-Px and Se-GSH-Px) in the liver of wild boars (Sus scrofa) selected from a selenium-deficient area with respect to season of the year, sex, and age. Only season had a significant effect on liver Se content. Liver selenium concentration in the wild boars was highest in spring (0.292 µg/g wet weight) and lowest in winter (0.185 µg/g wet weight) (P < 0.05). The highest mean activity of total GSH-Px, Se-GSH-Px, and CAT (404.0, 309.9, and 1170.0 U/mg protein, respectively) was found in the spring season, and the respective highest mean activity of SOD was found during autumn (31.5 U/mg protein). Females showed markedly higher mean activities of total GSH-Px (388.2 and 314.7 U/mg protein) and CAT (1151.0 and 765.8 U/mg protein) compared to males. In comparison to other groups of animals, those aged between 1 and 1.5 years were characterized by higher mean activity of total GSH-Px and Se-GSH-Px, and those over 2 years of age showed higher activity of CAT and SOD. The analysis showed that the strongest oxidative stress and the greatest risk of peroxidative damage to the liver occurred during the winter.

Ecotoxicological effects of salicylic acid in the freshwater fish Salmo trutta fario: antioxidant mechanisms and histological alterations.

The presence of pharmaceutical drugs in aquatic ecosystems has been widely reported during the past years. Salicylic acid (SA) is mainly used in human medicine as an analgesic and antipyretic drug, being also active in preventing platelet aggregation. To study the ecotoxicological effects potentially elicited by SA in freshwater fish, brown trout individuals (Salmo trutta fario) were chronically exposed (28days) to this drug, in order to evaluate the enzymatic and histological effects, in both gills and liver. A qualitative and semi-qualitative evaluation of the gills and liver was performed, and also a quantitative evaluation of various lamellar structures. Oxidative stress was quantified trough the determination of glutathione S-transferases (GSTs), glutathione reductase (GRed), total and selenium-dependent glutathione peroxidase (GPx) and Catalase (Cat) activities. Lipid peroxidative damage was also assessed by the quantification of thiobarbituric acid reactive substances (TBARS) in the liver. The here-obtained data showed the occurrence of oxidative stress, reflected by an increased activity of GPx and GRed in the liver; additionally, it was possible to observe non-specific histological changes in gills. The global significance of the entire set of results is discussed, giving emphasis to the ecological relevance of the responses.

The influence of vitamin-rich diet on the extent of lipoperoxidation in brain of mice during an acute post-insulin hypoglycaemia

Antioxidatives are widely used and recommended in common clinical praxis, even though they may have negative impact on our health under some circumstances (i.e. N-acetylcysteine, vitamin E, risk of lung cancer etc.). Our aim was to evaluate the role of exogenous scavengers in prevention of induced oxidative stress in rodents. Male ICR mice were used and acute hypoglycaemia was induced with insulin. The mice were randomized into eight experimental groups, either pretreated by vitamin C or vitamin E or combinations with respective vehicles. Total malondialdehyde (MDA), superoxide dismutase (SOD), and selenium-dependent glutathione peroxidase (GSHPx) activity were measured in brain tissue samples. ANOVA with a post-hoc Duncan or Turkey׳s tests were used for statistical evaluation. A statistically significant increase in brain MDA was observed after insulin-induced severe hypoglycaemia relative to normoglycaemia. Animals pretreated with vitamins, both in monotherapy and in combination (both P<0.05), had significantly lower MDA values compared with animals without pretreatment. Importantly, significant differences were also observed after combination of vitamin C and E in GSHPx and SOD (both P<0.05).

Expression of biotransformation and oxidative stress genes in the giant freshwater prawn Macrobrachium rosenbergii exposed to chlordecone.

Chlordecone is a persistent organochlorine pesticide widely used between 1972 and 1993 in the French West Indies to control the root borer in banana fields. Chlordecone use resulted in long-term pollution of soils, contamination of waters, of aquatic organisms, and of fields. Chlordecone is known to be neurotoxic, to increase prostate cancer, and to have negative effects on cognitive and motor development during infancy. In Guadeloupe, most of the freshwater species living in contaminated rivers exceed the French legal limit of 20μg·kg(-1) wet weight. In the present study, we chose a transcriptomic approach to study the cellular effects of chlordecone in the giant freshwater prawn Macrobrachium rosenbergii, an important economical species in Guadeloupe. Quantitative PCR revealed an induction of genes involved in defense mechanism against oxidative stress (catalase and selenium-dependent glutathione peroxidase) in prawns exposed to low environmental concentrations of chlordecone after 12 and 24h of exposure. In prawns reared in a contaminated farm, transcription of genes involved in the biotransformation process (cytochrome P450 and glutathione-S-transferase (GST)) were induced after 8days of exposure. Our results provide information on the mechanims of defense induced by chlordecone in aquatic crustacean species. This gene expression study of selected genes should be further strengthened by proteomic analyses and enzymatic activity assays to confirm the response of these biomarkers of stress in crustaceans and to give new insights into the mechanism of toxicity by chlordecone.

Effect of acetaminophen exposure in Oncorhynchus mykiss gills and liver: Detoxification mechanisms, oxidative defence system and peroxidative damage

The increasing presence of pharmaceutical drugs in nature is cause of concern due to the occurrence of oxidative stress in non-target species. Acetaminophen is widely used in human medicine as an analgesic and antipyretic drug, and it is one of the most sold non-prescription drugs. The present study aimed to assess the toxic effects of acetaminophen (APAP) in Oncorhynchus mykiss following acute and chronic exposures in realistic levels. In order to evaluate the APAP effects in the rainbow trout, gills and liver were analyzed with biochemical biomarkers, such as catalase (CAT), total and selenium-dependent glutathione peroxidase (GPx), glutathione reductase (GRed) and glutathione-S-transferases (GSTs) activity and also lipid peroxidation levels (TBARS). The results obtained in all tests indicate that a significant response of oxidative stress was established, along with the increase of APAP concentrations. The establishment of an oxidative stress scenario occurred with the involvement of all tested biomarkers, sustaining a generalized set of pro-oxidative effects elicited by APAP. Additionally, the occurrence of oxidative damage strongly suggests the impairment of the antioxidant defense mechanism of O. mykiss. It is important to note that the occurrence of oxidative deleterious effects and peroxidative damages occurred for concentrations similar to those already reported for several freshwater ecosystems. The importance of these assumptions is further discussed under the scope of ecological relevance of the assessment of effects caused by pharmaceuticals in non-target organisms.

Characterization and structural analysis of human selenium-dependent glutathione peroxidase 4 mutant expressed in Escherichia coli

Glutathione peroxidase 4 (GPx4) is a monomeric selenium-dependent glutathione peroxidase highly expressed in mammalian cells, which can reduce phospholipid hydroperoxides. However, it has been difficult to express recombinant mammalian GPx4 in Escherichia coli because of the differences in the selenocysteine (Sec) incorporation machinery between eukaryotes and prokaryotes. In this study, an E. coli BL21(DE3)cys auxotrophic strain was used to express GPx4 mutants. We found that untargeted substitution of Cys-2, Cys-37, Cys-75, Cys-107, and Cys-148 with Sec led to loss of activity, suggesting that mutation of any of these Cys residues in GPx4 could result in a structural change. Additionally, we found that the catalytic activity of GPx4 mutants increased as the number of noncatalytic Sec residues decreased, indicating that the negative effects could be mitigated by replacing these Cys residues with Ser residues. A GPx4 mutant with all Cys residues converted to Ser exhibited a “Ping–Pong” mechanism and structure similar to that of native GPx4, indicating that it could act as a substitute for GPx4, when heterologously expressing the protein in E. coli. This research provides an important foundation for biosynthesis of selenium-dependent GPx4 mutants in E. coli.

Effects of Selol 5% supplementation on the activity or concentration of antioxidants and malondialdehyde level in the blood of healthy mice

BackgroundSelol is a novel organoselenium Se(IV) compound. It reveals lower potential of toxicity than sodium selenite and does not exhibit mutagenic activity. Its antioxidant and anticancer properties including overcoming cancer cell resistance to standard therapy of the drug were proven. This is the first publication describing the influence of Selol 5% on the activity of blood antioxidant status in vivo. Materials and methodsWe investigated the influence of Selol 5% short-term (24h) and long-term (28 days) administration on the activity of antioxidant enzymes, including the main selenoenzymes, in healthy mice plasma and erythrocytes. Plasma oxygen radical absorbance capacity value (ORAC) and the concentration of malonyldialdehyde (MDA) in plasma as a biomarker of oxidative stress as well as the value of selenium (Se) concentration in erythrocytes were shown. ResultsA significant increase of the selenium dependent glutathione peroxidase (Se-GSHPx) activity in plasma and erythrocytes, plasma selenoprotein P concentration, ORAC values, and Se concentration were observed during long-term supplementation as well as after Selol 5% single-dose administration, with two distinct increases of activity a few hours after the beginning of the experiment and before its end. We found a decreased thioredoxin reductase (THRR) activity and an increased MDA level during Selol 5% long-term supplementation. Glutathione S-transferase activity (GST) remained unchanged. ConclusionSelol 5% supplementation in vivo affects the selenoenzymes activities as well as the antioxidant status of plasma and erythrocytes. Selol 5% is an inhibitor of thioredoxin reductase activity, which can be important in anticancer therapy.

Trace elements, magnesium, and the efficacy of antioxidant systems in children with type 1 diabetes mellitus and in their siblings.

Magnesium (Mg), selinium (Se), zinc (Zn), manganese (Mn), and copper (Cu) are involved in the mechanisms of antioxidant defense. Mn and Cu, which participate in the generation of reactive oxygen species (ROS), also have pro-oxidative properties. To evaluate the levels of Mg, Se, Zn, Mn, and Cu, as well as the effectiveness of antioxidant defense mechanisms in children with Type 1Diabetes Mellitus (T1DM) and in their siblings. The preliminary findings were originally reported in 2009 at the 35th annual conference of the International Society for Pediatric and Adolescent Diabetes (ISPAD) in Ljubljana, Slovenia. The study involved 87 children with T1DM, 2-19 years old, treated for T1DM for an average of 3.5 years. The sibling and control groups comprised 27 and 41 children, aged 4.5-16.5 years and 10.5-18 years respectively. The parameters named above were assessed in relation to metabolic compensation levels (HbA1C) and disease duration. Compared with the control group, T1DM children had lower plasma levels of Mg and Zn and higher levels of Cu; the siblings had lower levels of Zn; T1DM children had lower copper/zinc superoxide dismutase (CuZnSOD) activity; and both T1DM children and their siblings had higher catalase (CAT) activity and lower total antioxidant status (TAS) levels. There may be a correlation between impaired antioxidant status and Mg and Zn deficiency and increased Cu levels in T1DM children. Oxidative stress in T1DM is accompanied by alterations in enzymatic activity and non-enzymatic mechanisms of antioxidant defense. The decreased TAS levels noted in T1DM patients may impair the effectiveness of non-enzymatic antioxidant systems. The increased CAT activity and unimpaired selenium-dependent glutathione peroxidase (Se-GSHPx) activity point indirectly to enhanced ROS generation in T1DM children. The impaired antioxidant defense found in the siblings of T1DM patients may indicate that genetic factors play a role.

Oxidative stress enzyme status and frequency of micronuclei in heroin addicts in Turkey

Heroin is among the most widely used and dangerous addictive opiate. The World Health Organization (WHO) estimated that more than 15 million people are under the influence of opiate addiction. The aim of this study was to investigate copper zinc-superoxide dismutase (Cu,Zn-SOD), catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GPx) antioxidant enzyme activities, malondialdehyde (MDA) levels and the frequency of micronuclei (MN) in addicts using heroin, the most commonly abused opiate in Turkey. Addicts were defined as individuals diagnosed according to “Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV)” criteria by the “Alcohol and Substance Abuse Treatment and Education Centre-Ankara (AMATEM)”. The control group had no addiction. In comparisons between the groups, a significant decrease in Cu,Zn-SOD activity and increases in MDA levels and MN frequency were observed in addicts. It can be concluded that opiates may cause oxidative stress and that antioxidant supplementation, in addition to pharmacological and psychiatric approaches, can reduce the toxicological effects of these opiates.

Identification and mRNA expression of antioxidant enzyme genes associated with the oxidative stress response in the Wuchang bream (Megalobrama amblycephala Yih) in response to acute nitrite exposure

Aquatic organisms possess cellular detoxification systems to deal with pollutants. To explore the influence of reactive oxygen species (ROS) generated in response to nitrite on oxidative stress defenses and the antioxidant system in Megalobrama amblycephala, the full length cDNA sequences were determined for three antioxidant-related genes, namely catalase (MaCAT), selenium-dependent glutathione peroxidase (MaGPx1) and Cu/Zn superoxide dismutase (MaCu/Zn-SOD). Encoded polypeptides that exhibited high identity and similarity with corresponding proteins in other fish species. Expression levels of these antioxidant genes were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) technique. MaCAT, MaGPx1 and MaCu/Zn-SOD expression was greatest in the liver and qRT-PCR was used to assess expression of these genes in juvenile fish during 72h of exposure to 15mg/L nitrite. Prolonged nitrite exposure resulted in the formation of excess ROS that caused oxidative damage to lipids and proteins and reduced the activities of antioxidant enzymes. Fish exposed to nitrite also showed liver damage. This study provides transcriptional data for MaCAT, MaGPx1 and MaCu/Zn-SOD that suggest expression is related positively with oxidative stress induced by nitrite exposure, indicating that imbalance between ROS and antioxidant defenses is one mechanism underlying nitrite toxicity in M. amblycephala.

Pollution-related changes in oxidative stress and antioxidant defense profile in the blood of white stork Ciconia ciconia chicks from different regions of Poland

Changes in the lipid peroxidation and oxidatively modified protein levels as well as the antioxidant defense system in the blood of white stork (Ciconia ciconia) chicks were analyzed during their development in nests in polluted and control environments. The control, relatively pure, environment was the village of Klopot, with no industrial plants within a radius of 150 km. Blood samples were also collected in two polluted areas, including (1) the suburban village of Czarnowo, located 20 km from the city of Zielona Gora (southwestern Poland) and (2) an area near the town of Glogow, where a large copper smelter is situated. The effects of various ecological threats from different environments tended to initiate oxidative stress and decrease total antioxidant capacity. The initiation of lipid peroxidation and increases in the levels of carbonyl derivatives of oxidative amino acids were observed in the plasma of chicks from polluted areas. Plasma catalase and the selenium-dependent glutathione peroxidase activities of erythrocytes were significantly higher in chicks from polluted areas than in those from control areas. Oxidative stress and components of the antioxidant defense system, especially glutathione peroxidase activity, can be used as indicators of oxidative stress, which was found to be greater in the polluted areas (near the Glogow copper smelter). Research into oxidative stress biomarkers can aid assessments of the conditions of birds, and points to a positive association with miscellaneous environmental loads.

Expression profiles of selenium dependent glutathione peroxidase and glutathione S-transferase from Exopalaemon carinicauda in response to Vibrio anguillarum and WSSV challenge

A selenium-dependent glutathione peroxidase cDNA was obtained from the ridgetail white prawn Exopalaemon carinicauda (EcGPx) by rapid amplification of cDNA ends (RACE) methods. The full-length cDNA of EcGPx was 946 bp, which contains a 5′-untranslated region (UTR) of 105 bp, 3′-UTR of 280 bp with a poly (A) tail, an open reading frame (ORF) of 561 bp, encoding a 186 amino-acid polypeptide with the predicted molecular weight of 21.35 kDa and estimated isoelectric point of 7.65. It involves a putative selenocysteine (U39) residue which is encoded by an opal codon, 220TGA222, and forms an active site with residues Q73 and W141. Sequence analysis revealed that a GPx signature motif 2 (63LAFPCNQF70), an extra active site motif (151WNFEKF156), two putative N-glycosylation site (75NNT77 and 107NGS109), and two arginine residues (R89 and R167) were observed in the EcGPx sequence. Comparison of amino acid sequences showed that white shrimp GPx is more closely related to GPx1 and GPx2 subgroups. Quantitative real-time RT-PCR analysis indicated that two glutathione antioxidant enzymes of E. carinicauda, glutathione peroxidase (designated EcGPx) and glutathione S-transferase (designated EcGST) were widely expressed in all the tested tissues, but showed different expression patterns. After Vibrio anguillarum and WSSV challenge, EcGPx and EcGST transcripts both in hemocytes and hepatopancreas increased in the first 6 h and 3 h, respectively. The results suggested that EcGPx and EcGST might be associated with the immune defenses to V. anguillarum and WSSV in E. carinicauda.

Effects of chronic carbosulfan exposure on liver antioxidant enzyme activities in rainbow trout

Catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and selenium-dependent glutathione peroxidase (Se-GPx) activities in liver of rainbow trout (Oncorhynchus mykiss; 116.88±21.69g) were evaluated after exposing fish to sublethal concentrations (25μg/L) of carbosulfan in flow-through tanks for 60 days. During the experiment activities of CAT, SOD, GST, and Se-GPx and histopathological effects were determined once a week and once at the end of the 21 days of recovery period. All enzymes were affected by carbosulfan when compared to control fish. Fish had intracellular oedema, cell necrosis, pycnotic nucleus, and increase of sinusoidal space in the liver. After 21 days of the recovery period, all enzyme activities had returned to control levels and fish had no histological lesions in liver. Therefore all the changes observed during exposure were reversible. Results indicate that the liver CAT, SOD and GST enzymes are highly sensitive to carbosulfan as their activities altered significantly, suggesting they could be useful in predicting sublethal pesticide toxicity and useful as an indicator for assessment of pesticides in contaminated water.

Effects of Smoking during Pregnancy on DNA Damage and ROS Level Consequences in Maternal and Newborns’ Blood

Some of the genotoxic/carcinogenic substances or metabolites in cigarette smoke are capable of passing through the placenta and harming a newborn’s health. Smoking is also known as a factor in the formation of oxidative damage and the main mechanism involved in the carcinogenic process. Predetermining this genotoxic risk can be successfully achieved by measuring certain parameters of oxidative stress. The comet assay is considered an important biomarker for the evaluation of genotoxic substances and is effective for detecting DNA damage caused by smoking. This study examined third trimester bloods and the cord blood of 28 actively smoking and 22 non-smoking mothers in terms of DNA damage and oxidative stress parameters. Cu/Zn superoxide dismutase (CuZn-SOD), malondialdehyde (MDA), catalase (CAT), plasma nitrite/nitrates (NO2-/NO3-), selenium-dependent glutathione peroxidase (Se-GPx), Cu, and Zn levels were measured as indicators of oxidative damage. There were no significant increases in DNA damage of the actively smoking pregnant group in comparison with the non-smoking pregnant group, either in the third trimester or cord blood. Oxidative stress parameters of smoker and non-smoker groups were statistically different for MDA (p<0.05), CuZn-SOD (p<0.01), Se-GPx (p<0.05) values while the difference was not significant for NO2-/NO3-, CAT, Zn, and Cu values. The same values were also investigated in cord blood,and only NO2/NO3-(p<0.01), Se-GPx (p<0.01 and CAT (p<0.001) values were found statistically different.Smoking mothers may have been exposed to more oxidative stress than non-smoking mothers

English

Intraperitoneal injection of rats with diethyldithiocarbamate (1.2 g/kg body weight) led to a maximum diminution of glutathione reductase at 12 hr by 40% and 56% in liver and red blood cells respectively, with a gradual return to the normal level at 48 hr after administration. Significant inhibition of reduced glutathione was also observed, which returned to normal at 48 hr after administration. However, maximum decline in its content was at 12 hr by 71% and 37% in liver and red blood cells respectively. A similar pattern was exhibited with respect to liver and serum ceruloplasmin in the diethyldithiocarbamate injected rats. It is possible that oxidant stress is developed in the rats by the administration of diethyldithiocarbamate with concomitant decrease in the activity of antioxidant enzymes and the other antioxidants such as reduced glutathione and ceruloplasmin. INTRODUCTION: Intraperitoneal injection of rats with diethyldithiocarbamate (DDC), a powerful copper chelator, causes decline in superoxide dismutase in various tissues of experimental animals. 1,2 DDC administration to rats significantly decreased the cellular activity of selenium-dependent glutathione peroxidase. 3 There are several metabolic processes which generate superoxide anion radical (O 2 -) in the respiring cells. 4 If these radicals are not effectively removed, they are toxic to the cells due to their ability to promote lipid peroxidation 4,5 and to provoke the denaturation of certain enzymes.6 Superoxide dismutase, which catalyses the dismutation of O 2 - is considered to be the essential enzyme in the defense against the toxic effects of O 2 - . Maintenance of intracellular level of this enzyme is necessary to prevent free radical toxicity. In view of these reports, it was felt necessary to study the effect of DDC administration on the levels of glutathione reductase and reduced glutathione in liver and erythrocytes and serum ceruloplasmin of rats. This study is aimed at establishing the mutually supportive role of the antioxidant enzymes such as superoxide dismutase, glutathione peroxidase, glutathione reductase, ceruloplasmin and antioxidant such as reduced glutathione. MATERIALS AND METHODS: CHEMICALS: Bovine serum albumin (fraction V) and 5, 5 - dithiobis 2- nitrobenzoic acid were purchased from Sigma Chemical Company (St. Louis MO,