Oxidative stress in digestive gland and gill of the brown mussel (Perna perna) exposed to air and re-submersed

Mussels Perna perna were exposed to air for 24 h showing a clear increase in the levels of lipid peroxidation and oxidative DNA damage, measured as 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo). The levels of lipid peroxidation increased both in the digestive gland and gills, while oxidative DNA damage increased only in the gills. After the 24 h of air exposure, mussels were re-submersed for a period of 3 h, leading values to return to a pre-aerial exposure levels. Control animals were kept immersed during the whole period. Several antioxidant and complementary enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), glutathione S-transferase (GST) and the levels of total glutathione (Total GSH) were assayed in a second set of experiments where one group of mussels were exposed to air for 18 h and other to 1 h re-submersion after 18 h aerial exposure. Only a 52% increase in the glutathione S-transferase activity was observed in the digestive gland, which remained elevated to about 40% after 1 h re-submersion, showing that defense systems can be modulated even during oxygen deprivation in P. perna. The DNA and lipid oxidative damage observed after aerial exposure indicates that mussels face an oxidative challenge, and are able to counteract such an “insult” as values of lipid peroxidation and DNA damage returned to control values after 3 h re-submersion.     

A serine protease inhibitor from hemolymph of green mussel, Perna viridis

Bioactivity guided fractions of cell-free hemolymph of bacterially challenged marine mussel, Perna viridis led to the isolation of a novel quaternary alkaloid 1, which was identified by its spectral data. The isolated molecule 1 has been found to be a potent serine protease inhibitor (SPI) showing IC₅₀ and K_i values of 102.5 and 97.1–104.68 μM, respectively. The E_t/K_i value of SPI is 6.3, whereas E_t/K_m value is 1.04. The Van’t Hoff analysis showed that the value of K_i decreases with increase in temperature, and the binding of the inhibitor is entropically driven.     

Nasturtium officinale reduces oxidative stress and enhances antioxidant capacity in hypercholesterolaemic rats

Nasturtium officinale R. Br. (Brassicaceae) has been used as a home remedy by the people of south eastern (SE) region of Iran as a medicinal plant. This therapeutical application has been attributed to Nasturtium officinale (N. officinale) antioxidant capacity which is mostly tested by means of cell-free assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). In addition, the antioxidant effect of N. officinale extract has been investigated in hypercholesterolaemic rats in vivo. The results revealed that the extract has notable scavenging activity against DPPH radicals as well as potent reducing power in FRAP assay. Intragastric administration of N. officinale (500 mg/kg body weight per day) to groups of hypercholesterolaemic rats for 30 days lowered their blood total cholesterol (TC), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) levels by 37, 44 and 48%, respectively. However, the blood high density lipoprotein cholesterol (HDL-C) levels in the same treated rats increased by 16%. To evaluate the mechanism(s) of action, we studied the antioxidative potential of N. officinale extract in terms of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) activities and also the level of reduced glutathione (GSH) in the liver tissues. In addition, hepatic tissue malondialdehyde level (MDA, an index of lipid peroxidation) was also determined. Under hypercholesterolaemic condition, hepatic MDA was increased. Moreover, our data indicated GSH depletion along with significant reduction in the activities of CAT and SOD in rats fed high-fat diet rats. On the other hand, significant elevation in the activities of GPx and GR were seen in the same group of rats. Treatment of hypercholesterolaemic rats with N. officinale extract significantly increased the GSH level along with enhanced CAT and SOD activities in liver tissues. Furthermore, N. officinale extract significantly decreased hepatic MDA as well as GPx and GR activities in plant-treated rats. Based on our data, it can be concluded that N. officinale has a high hypolipidaemic activity and this may be attributed to its antioxidative potential.     

Effects of vanadate on male rat reproductive tract histology, oxidative stress markers and androgenic enzyme activities

Vanadium has been recognized as industrial hazards that adversely affect male reproductive systems of humans and animals. However, less information is available concerning the underlying mechanism in the pathogenesis of male reproductive dysfunction. The present study investigated the possible involvement of oxidative stress to induce oxidative deterioration of testicular functions in adult rats. The results of in vitro and in vivo studies demonstrate that vanadium treatment resulted in a significant dose- and time-dependent increase in the testicular lipid peroxidation, marked inhibition in the level of superoxide dismutase and catalase activities, decreased sperm counts, and substantially inhibited the activities of Delta(5)3beta- and 17beta-hydroxysteroid dehydrogenase as well as serum testosterone level. Histopathological examination revealed inhibition of spermatogenesis and the preferential loss of maturing and elongated spermatids along with increased percent of abnormal sperm. Taken together, the results suggest that an increase in free radical formation relative to loss of antioxidant defense system during vanadium exposure may render testis more susceptible to oxidative damage leading to their functional inactivation. Thus the toxic effects of vanadium are cumulative and that vanadium produced damages in testes are dose- and time-dependent.     

Oxidative stress and antioxidant defense responses by goldfish tissues to acute change of temperature from 3 to 23 °C

The effects of a rapid transfer from a low (3 °C) to a warm (23 °C) temperature on oxidative stress markers and antioxidant defenses were studied in the brain, liver and kidney of the goldfish, Carassius auratus. Cold-acclimated fish were acutely moved to 23 °C and sampled after 1, 6, 12, 24, 48 or 120 h of warm temperature exposure. Lipid peroxide levels increased quickly during the first few hours at 23 °C, but thiobarbituric acid-reactive substances changed little. Protein carbonyl content was reduced by 20–40% in the liver over the entire experimental course, but increased transiently in the kidney. The content of high-molecular mass thiols decreased by two-thirds in the brain and was affected slightly in other organs. By contrast, total low-molecular mass thiols (e.g. glutathione and others) increased transiently. Activities of the primary antioxidant enzymes—superoxide dismutase and catalase—were generally unaffected in goldfish organs, whereas glutathione-dependent enzymes were elevated in the brain and kidney after 24–48 h at 23 °C. Glutathione peroxidase increased by 1.5–2.3-fold and glutathione-S-transferase by 1.7-fold. Hence, a short-term exposure to warm temperature disturbed several oxidative stress markers, but only slightly affected the activities of antioxidant enzymes. However, comparison of the current data for cold-acclimated winter fish with the same parameters in summer fish suggests that longer exposure to high ambient temperature requires the enhancement of activities of glutathione-dependent enzymes for maintaining the steady-state levels lipid peroxidation and protein oxidation in goldfish tissues.     

Cold-stress-induced modulation of antioxidant defence: role of stressed conditions in tissue injury followed by protein oxidation and lipid peroxidation

The aim of this study was to determine the effects of cold stress on antioxidant enzyme activities and examine protein oxidation and lipid peroxidation in various tissues (brain, liver, kidney, heart and stomach). Twenty male Wistar rats (3 months old) weighing 220 ± 20 g were used. The rats were randomly divided into two groups of ten: the control group and the cold stress group. Cold stress was applied to the animals by maintaining them in a cold room (5 °C) for 15 min/day for 15 days. Blood samples were taken for measuring plasma corticosterone levels. Tissues were obtained from each rat for measuring the antioxidant enzyme activities, protein oxidation and lipid peroxidation. Corticosterone levels were increased in the cold stress group. Copper, zinc superoxide dismutase activities were increased in the brains, livers and kidneys, whereas they decreased in the hearts and stomachs of rats in the cold stress group. Catalase activities were increased in the brains, livers, kidneys and hearts, whereas they decreased in the stomachs of rats in the cold stress group. Selenium-dependent glutathione peroxidase activities were increased in the brain, liver, heart and stomach. Reduced glutathione levels were decreased, while levels of protein carbonyl, conjugated diene and thiobarbituric-acid-reactive substances were increased in all tissues of the cold stress group. These results lead us to conclude that cold stress can disrupt the balance in an oxidant/antioxidant system and cause oxidative damage to several tissues by altering the enzymatic and non-enzymatic antioxidant status, protein oxidation and lipid peroxidation.     

No evidence for oxidative stress as a mechanism of action of hyperhomocysteinemia in humans

Oxidative stress has been suggested as one of the physiopathologic conditions underlying the association of total plasma homocysteine (p-tHcy) with cardiovascular disease (CVD), but this hypothesis has not been validated in human epidemiological studies. We measured plasma and erythrocyte antioxidant enzymes glutathione peroxidase (GPx) and superoxide dismutase (SOD), along with serum lipid-soluble antioxidants alpha-tocopherol, beta-carotene, lycopene and retinol, in a sample of 123 healthy elderly subjects (54 men, 69 women). Plasma malondialdehyde (p-MDA) was determined as a marker of lipid peroxidation, and p-tHcy was quantified by HPLC. No significant differences were found for p-MDA, GPx or SOD activities or serum antioxidant concentrations, in subjects with elevated p-tHcy (≥15 μmol/l) as compared to those with lower plasma homocysteine. Hyperhomocysteinemia did not lead to increased risk of having the highest p-MDA values, in either sex. We found no evidence that p-tHcy was associated with lipid peroxidation in this elderly human sample. Our results do not support the view that hyperhomocysteinemia would induce an adaptive response of antioxidant systems, either. More epidemiologic and clinical research is needed to clarify whether homocysteine promotes atherosclerosis by means of an oxidative stress mechanism.     

Genotoxicity and oxidative stress in fish after a short-term exposure to silver nanoparticles

This study examined the effects of waterborne silver nanoparticles (AgNPs) on juvenile fish Piaractus mesopotamicus (“pacú”), and analyzed toxicological endpoints such as metal burdens, oxidative stress and genotoxicity in a short-term assay. Fish were individually exposed to 0 (control), 2.5, 10, and 25 μg AgNPs/L. After 24 h, silver accumulation was greater in the brain than the liver and gills at all silver concentrations. Fish exposed to higher AgNPs concentrations showed major alterations in oxidative stress markers. An increase in lipid peroxidation (LPO) levels was observed in the liver of fish exposed to 10 μg AgNPs/L with no changes in the antioxidant enzymes activities. In the case of the 25 μg AgNPs/L treatment, a hepatic activation of the enzymatic antioxidant defense occurred, and LPO levels resulted unaltered. On the other hand, the brain presented the highest LPO levels at both 10 and 25 μg AgNPs/L exposures. The AgNPs toxicity was also evidenced by the DNA damage in fish erythrocytes at higher concentrations. Summarizing, a short exposure to sublethal concentrations of AgNPs is enough to generate deleterious effects on fish, including DNA damage.     

Aortic coarctation induces oxidative stress in rat tissues

The purpose of this study was to evaluate the induction of oxidative stress in heart and erythrocytes from rats with abdominal aorta coarctation (Coa) compared with sham-operated normotensive controls (Sham). The group of Coa animals developed myocardial hypertrophy, showing heart homogenates markedly increased levels of reduced glutathione (48%), lipid peroxidation (148%) and activation of superoxide dismutase and glutathione peroxidase (189% and 37%, respectively), compared with controls. Other oxidative stress indicators were also altered in erythrocytes from Coa rats: increased protein carbonyl content (141%) and total glutathione level (349%) were determined. Inactivation of the antioxidant enzymes catalase (27%), superoxide dismutase (58%) and glutathione peroxidase (25%) was observed in erythrocytes from the Coa group. Taken jointly our results provide strong evidence for the production of oxidative stress in heart and erythrocytes from aortic coarcted rats.     

Accumulation, depuration and distribution of cadmium and zinc in the green-lipped mussel Perna viridis (Linnaeus) under laboratory conditions

Ecotoxicological tests were conducted in the green-lipped mussel Perna viridis under laboratory conditions. Different rates of accumulation and depuration in soft tissues are found and this might be due to different mechanisms of metal binding and regulation. At the end of depuration, Cd levels in soft tissues of P. viridis were 10–30 times higher than before exposure, while Zn levels in soft tissues were almost similar to levels before exposure. These results indicate that P. viridis is a good biomonitoring organism for Cd but Zn levels might be actively regulated. It remains uncertain whether P. viridis is a good biomonitoring organism of environmental Zn contamination. However, the positive patterns, although different rates, of accumulation and depuration for Cd and Zn support the use of P. viridis as a biomonitoring agent for such metals.     

微囊藻细胞抽提物亚慢性暴露导致小鼠肝脏氧化应激

研究了微囊藻细胞抽提物亚慢性暴露对小鼠肝脏抗氧化系统的影响.采用腹腔注射进行连续染毒28d,染毒组剂量为3.3μg micmcystins/kg体重.结果显示,超氧化物歧化酶、过氧化氧酶、谷胱甘肽过氧化物酶在第4周时发生显著性升高,提示微囊藻细胞抽提物激活了小鼠肝脏抗氧化系统.谷胱甘肽-S-转移酶和对照组相比也显著提高,表明谷胱甘肽-S-转移酶作为解毒Ⅰ相酶加快了对肝脏微囊藻毒素的清除.脂质过氧化产物丙二醛也显著升高,说明抗氧化系统未能清除微囊藻细胞抽提物对小鼠肝脏的氧化损伤,导致了氧化应激的产生.结果表明低剂量微囊藻细胞抽提物长时间暴露能够导致小鼠肝脏氧化损伤.     

Involvement of oxidative stress and role of antioxidative defense system in growing rice seedlings exposed to toxic concentrations of aluminum

When seedlings of rice (Oryza sativa L.) cultivar Pant-12 were raised in sand cultures containing 80 and 160 μM Al³⁺ in the medium for 5–20 days, a regular increase in Al³⁺ uptake with a concomitant decrease in the length of roots as well as shoots was observed. Al³⁺ treatment of 160 μM resulted in increased generation of superoxide anion (O₂ ⁻) and hydrogen peroxide (H₂O₂), elevated amount of malondialdehyde, soluble protein and oxidized glutathione and decline in the concentrations of thiols (-SH) and ascorbic acid. Among antioxidative enzymes, activities of superoxide dismutase (SOD EC 1.15.1.1), guaiacol peroxidase (Guaiacol POX EC 1.11.1.7), ascorbate peroxidase (APX EC 1.11.1.11), monodehydroascorbate reductase (MDHAR EC 1.6.5.4), dehydroascorbate reductase (EC 1.8.5.1) and glutathione reductase (EC 1.6.4.2) increased significantly, whereas the activities of catalase (EC EC 1.11.1.6) and chloroplastic APX declined in 160 μM Al³⁺ stressed seedlings as compared to control seedlings. The results suggest that Al³⁺ toxicity is associated with induction of oxidative stress in rice plants and among antioxidative enzymes SOD, Guaiacol POX and cytosolic APX appear to serve as important components of an antioxidative defense mechanism under Al³⁺ toxicity. PAGE analysis confirmed the increased activity as well as appearance of new isoenzymes of APX in Al³⁺ stressed seedlings. Immunoblot analysis revealed that changes in the activities of APX are due to changes in the amounts of enzyme protein. Similar findings were obtained when the experiments were repeated using another popular rice cv. Malviya-36.     

Greening of the coasts: a review of the Perna viridis success story

The green mussel Perna viridis has been receiving a lot of attention from workers working in the research areas of intertidal ecology, aquaculture, pollution monitoring, biofouling, zoogeography and invasion biology. P. viridis is a remarkable species in terms of its ability to reach very high biomass levels, to withstand environmental fluctuations, to concentrate a variety of organic and inorganic environmental pollutants, to colonise artificial marine habitats and to invade new geographic territories. This review collates data available on salient aspects of the distribution, biology and ecology of P. viridis. It is argued that the remarkable success of P. viridis as an invasive species basically stems from its long larval duration, fast growth rate, high fecundity, early maturity, high productivity and ability to withstand fluctuating environmental conditions (temperature, salinity, water turbidity and pollutants). Relevant aspects of the data are compared with the data available for a similar species Perna perna, which too is an invasive species, but to a more limited extent.     

Tissue-specific oxidative stress responses in fish exposed to 2,4-D and azinphosmethyl

Species- and tissue-specific defenses against the possibility of oxidative stress and lipid peroxidation were compared in adult fish, Oreochromis niloticus and Cyprinus carpio, exposed to 2,4-dichlorophenoxyacetic acid (2,4-D), azinphosmethyl and their combination for 96 h. Superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase activities were monitored in kidney, brain and gill. In all exposure groups there was a marked increase in SOD activity in gill tissues in both fish species, while it was at the control level in other tissues. The highest elevation of SOD activity by combined treatment was observed in C. carpio. Individual and combined treatments caused an elevation in catalase and GPx activities in kidney of C. carpio. Catalase activity was unaffected in brain of O. niloticus, while GPx activity was decreased after all treatments. Glutathione S-transferase (GST) activity was higher than the control levels in kidney of both fish exposed to pesticides. No significant changes were observed in malondialdehyde level in kidney and brain of C. carpio. Our results indicate that the toxicities of azinphosmethyl and 2,4-D may be related to oxidative stress. Also, the results show that SOD activity in gill and GST activity in kidney may be used as biomarkers for pollution monitoring and indicate that the activities of certain biomarkers in C. carpio are more sensitive to pesticides than those in O. niloticus.     

Chilling,oxidative stress and antioxidant responses inArabidopsis thaliana callus

Chilling ofArabidopsis thaliana (L.) Heynh. callus tissue to 4 °C led to conditions of oxidative stress, as indicated by increased levels of the products of peroxidative damage to cell membranes. Cellular H₂O₂ was also observed to increase initially upon chilling but by day 8 cellular levels had declined to below control levels. Although levels of catalase activity remained similar to those in unchilled tissue, activity of ascorbate peroxidase increased between days 4 and 8 of chilling to 4 °C. In callus held at 23 °C, levels of reduced glutathione remained static whereas they rose in callus held at 4 °C. Levels of oxidised glutathione were initially low but increased significantly by day 4 in the chilled callus. At 23 °C, however, levels of oxidised glutathione remained low. Between days 1 and 3 at 4 °C, levels of glutathione reductase activity increased but by day 8 glutathione reductase activity was similar to that in cells held at 23 °C. Exposure of callus to abscisic acid at 23 °C also led to increased activities of ascorbate peroxidase and glutathione reductase.Abbreviations ABA abscisic acid - GSH reduced glutathione - GSSG oxidised glutathione - TTC 2,35-triphenyltetrazolium chloride This work is supported by a grant from the Biotechnology and Biological Sciences Research Council.     

Effects of Onosma armeniacum root extract on ethanol-induced oxidative stress in stomach tissue of rats

This study investigated the effects of Onosma armeniacum K. (Boraginaceae) root extract (AR-1) on ethanol-induced stomach ulcers, and on some oxidant and antioxidant parameters, in stomach tissue in rats. The results obtained showed that AR-1 significantly inhibited ethanol-induced ulcers at 25, 50, 100 and 200 mg/kg doses. We found that 50, 100 and 200 mg/kg doses of AR-1 inhibited ulcers more effectively than did ranitidine. AR-1 at doses of 25, 50, 100 and 200 mg/kg significantly prevented the decrease in total glutathione (tGSH) level which occurs in damaged stomach tissues of rats given ethanol (control group). Only a 100 mg/kg dose of AR-1 significantly increased the glutathione S-transferase (GST) level in stomach tissue compared to the control. All doses of AR-1 except the 25 mg/kg dose eliminated the decrease in the superoxide dismutase (SOD) level in the stomach tissue of rats given ethanol. While all doses of AR-1 decreased malondialdehyde (MDA) levels significantly; all doses AR-1 except 25 mg/kg decreased myeloperoxidase (MPO) levels significantly compared to the control. The effect of AR-1 on catalase (CAT) activity was insignificant at all doses. AR-1 significantly increased nitric oxide (NO) levels at 50, 100 and 200 mg/kg doses compared to the control. Our results indicate that the protection of some antioxidant mechanisms and the inhibition of some oxidant mechanisms have a role in AR-1's antiulcer effect mechanism.     

温度和紫外辐射胁迫对西藏飞蝗抗氧化系统的影响

为探讨西藏飞蝗(Locusta migratoria tibetensis Chen)对环境的适应机制,报道了温度和紫外辐射胁迫对西藏飞蝗抗氧化系统影响。以西藏飞蝗成虫为试材,研究5—20℃低温、30—45℃高温胁迫和紫外线辐射对其抗氧化酶活性和膜脂过氧化物丙二醛(MDA)含量的影响。在5—20℃低温胁迫下,成虫体壁和消化道超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及丙二醛(MDA)含量分别随温度降低而升高;在30—35℃高温胁迫下,成虫SOD、POD和CAT活性分别随温度升高而升高,当温度超过35℃时,3种氧化酶活性均下降。长波紫外辐射(UV-A)和中波紫外辐射(UV-B)对处理后24h和72h成虫的SOD活性的影响大于可见光,在UV-A、UV-B和可见光3种光波长处理下,成虫的POD和CAT活性随光照时间的延长而增加,其中UV-B对两种酶活性影响大于UV-A和可见光,表现为UV-B处理组>UV-A处理组>可见光处理组;UV-A和UV-B处理能导致虫体体壁MDA含量明显升高,且对脂质过氧化的诱导存在时间效应;雌虫体壁、雌虫消化道、雄虫体壁和雄虫消化道的MDA含量分别在UV-B72h、UV-A72h、UV-A72h和UV-B72h达最大值0.72、0.88、0.66和0.94 nmol/g鲜重。在20—5℃低温胁迫下,西藏飞蝗成虫抗氧化酶活性升高,能较好的保护自身免遭活性氧自由基的伤害;西藏飞蝗对高温忍耐力差,在高于35℃高温胁迫下,成虫SOD、POD、CAT活性均下降;在长波和中波紫外辐射下,西藏飞蝗抗氧化酶活性显著升高,是西藏飞蝗对紫外线辐射强度大的青藏高原的一种重要适应。     

The golden root, Rhodiola rosea, prolongs lifespan but decreases oxidative stress resistance in yeast Saccharomyces cerevisiae

The effect of aqueous extract from R. rosea root on lifespan and the activity of antioxidant enzymes in budding yeast Saccharomyces cerevisiae have been studied. The supplementation of the growth medium with R. rosea extract decreased survival of exponentially growing S. cerevisiae cells under H₂O₂-induced oxidative stress, but increased viability and reproduction success of yeast cells in stationary phase. The extract did not significantly affect catalase activity and decreased SOD activity in chronologically aged yeast population. These results suggest that R. rosea acts as a stressor for S. cerevisiae cells, what sensitizes yeast cells to oxidative stress at exponential phase, but induces adaptation in stationary phase cells demonstrating the positive effect on yeast survival without activation of major antioxidant enzymes.