饲料中添加谷胱甘肽对吉富罗非鱼抗氧化和抗亚硝基氮应激能力的影响

选择初始体重(3.27±0.04)g的吉富罗非鱼(GIFT Oreochromis niloticus),分别投喂基础饲料和添加80、160、240、320和400 mg/kg谷胱甘肽(GSH)的试验饲料,记作G0、G80、G160、G240、G320和G400。49 d后,G320血清和G160、G240肝脏谷胱甘肽S-转移酶,G160、G240血清和G320肝脏谷胱甘肽还原酶,G240肝脏超氧化物歧化酶,G320血清和G240肝脏过氧化氢酶活性,G240～G400血清和G240肝脏总抗氧化能力,G320血清抗超氧阴离子活性,与对照组相比分别显著升高。G80～G320肝脏丙二醛含量显著低于对照组。在亚硝基氮应激96 h内,G320累积死亡率显著降低。结果表明,饲料中添加一定量的GSH能显著提高罗非鱼的抗氧化性能和抗亚硝基氮应激能力。     

Lowered Antioxidant Status of Red Blood Cells in Post-Parturient Haemoglobinuria of Buffaloes

The antioxidant status of the red blood cells of buffaloes (n = 20) suffering from post-parturient haemoglobinuria (PPH) was assessed by comparing their tocopherol (vitamin E) and reduced glutathione contents with those of red blood cells from apparently healthy buffaloes (n = 20). The red cell tocopherol content of the diseased buffaloes (1.76±0.11 g/ml) was significantly (p<0.01) lower than that of healthy buffaloes (2.45±0.14 g/ml). This may be the first report comparing the concentration of tocopherol in the red blood cells of buffaloes suffering from PPH and apparently healthy buffaloes.There was a drastic reduction in the reduced glutathione content in the red cells of haemoglobinuric buffaloes (23.74±2.86 mg%) compared to the healthy control buffaloes (73.71±3.87 mg%). The diseased buffaloes also exhibited severe hypophosphataemia. These findings suggest that an impaired or insufficient antioxidant potential of the red blood cells in this disease in buffaloes is associated with the phosphorus deficiency.     

The effects of dietary oxidized fat and selenium source on performance,glutathione peroxidase,and glutathione reductase activity in broiler chickens

Normal or elevated selenium status of broilers, which is influenced by dietary selenium sources, improves the bird’s ability to overcome the adverse effects of reactive oxygen metabolites. The objective of this study was to evaluate the effects of feeding graded levels of peroxidized poultry fat on blood and hepatic glutathione peroxidase (GSH-Px), and hepatic glutathione reductase activity in broiler chickens fed either inorganic sodium selenite (SEL) or organic selenium enriched in the organic selenium yeast product Sel-Plex (SP). Nine starter diets, varying in levels of oxidized fat (0, 3, and 6 mEq/kg) and dietary selenium sources, were fed to 360 male chicks from hatch to 21 d of age. Sel-Plex or SEL was added to the basal diet to provide either 0 or 0.2 ppm of supplemental selenium in the diets. Blood and hepatic samples were obtained for each treatment group at 21 d of age. Neither peroxidized fat nor selenium source significantly altered the activity of hepatic glutathione reductase (P ≤ 0.05). Blood GSH-Px was influenced significantly by both fat and selenium source (P ≤ 0.05), but the fat × selenium source interaction was not significant (P ≥ 0.3). A selenium source effect on the hepatic GSH-Px activity (P ≤ 0.05) was evidenced by higher GSH-Px activity, even in the basal diet with no added peroxidized fat. An increase in GSH-Px activity was seen in the erythrocyte and hepatic samples in both the SEL and SP treatments when peroxidized fat was given at 3 mEq/kg, but in the erythrocytes and in the hepatic tissues from SEL-supplemented birds, there was an apparent inhibition of GSH-Px activity. This inhibition was not seen in the hepatic tissue samples from SP-fed birds. Because elevated GSH-Px activity is indicative of oxidative stress, it was concluded that dietary SP supplementation resulted in better selenium and redox status in broilers than did SEL. These results indicate that the dietary selenium supplied in an organic form (selenium yeast as SP) improved the selenium and redox status in broilers, leading to greater resistance to oxidative stress than when the inorganic form of selenium (SEL) was fed.     

The effect of different concentrations of linseed oil or fish oil in the maternal diet on the fatty acid composition and oxidative status of sows and piglets

N‐3 polyunsaturated fatty acids (PUFA) are essential for foetal development. Hence, including n‐3 PUFA in the sow diet can be beneficial for reproduction. Both the amount and form (precursor fatty acids vs. long chain PUFA) of supplementation are important in this respect. Furthermore, including n‐3 PUFA in the diet can have negative effects, such as decreased arachidonic acid (ARA) concentration and increased oxidative stress. This study aimed to compare the efficacy to increase eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations in the piglet, when different concentrations of linseed oil (LO, source of precursor α‐linolenic acid) or fish oil (FO, source of EPA and DHA) were included in the maternal diet. Sows were fed a palm oil diet or a diet including 0.5% or 2% LO or FO from day 45 of gestation until weaning. Linoleic acid (LA) was kept constant in the diets to prevent a decrease in ARA, and all diets were supplemented with α‐tocopherol acetate (150 mg/kg) and organic selenium (0.4 mg/kg) to prevent oxidative stress. Feeding 0.5% LO or 0.5% FO to the sows resulted in comparable EPA concentrations in the 5‐day old piglet liver, but both diets resulted in lower EPA concentrations than when 2% LO was fed. The highest EPA concentration was obtained when 2% FO was fed. The DHA level in the piglet liver could only be increased when FO, but not LO, was fed to the sows. The 2% FO diet had no advantage over the 0.5% FO diet to increase DHA in the piglet. Despite the constant LA concentration in the sow diet, a decrease in ARA could not be avoided when LO or FO were included in the diet. Feeding 2% FO to the sows increased the malondialdehyde concentration (marker for lipid peroxidation) in sow plasma, but not in piglets.     

Glutathione and its Related Enzymes in the Nile Fish

Glutathione (GSH) and related enzymes, glutathione transferase (GST), glutathione peroxidase (GPx) and glutathione reductase (GR) form an important phase 2 biotransformation enzymes system. The objective of this study was to compare this enzymes system in three fish species from the river Nile, Oreochromis niloticus, Claris lazera and Cyprinus carpio in order to establish the main differences and to purify and characterize GST from the liver of O. niloticus.The level of GSH and the activity of GST, GPx and GR in the liver, kidney and gills of the three fish species were examined. A simple reproducible procedure for the purification of GST from the liver of O. niloticus to homogeneity, which includes chromatography on DEAE- cellulose followed by affinity chromatography on GSH-sepharose was established. The molecular mass was found to be 25,460 Da by SDS-PAGE. The Michaelis-Meneten constants (K_m) of the enzyme for GSH and CDNB were 0.35 mM and 0.42 mM, respectively. The affinity purified enzyme exhibited maximum pH at pH 8.0 and increasing pH above 8.0 did not affect the observed maximum. The purified enzyme acts readily on CDNB, less readily on some standard transferase substrates (1,2-dichloro-4-nitrobenzene and p-nitrophenethyl bromide) and not at all on others (bromosulphophthalein and p-nitrobenzyl chloride). Bromosulfophthalein, cibacron blue and hematin inhibited CDNB-conjugating activity of the purified enzyme with IC₅₀ 0.079, 3.98 and 0.126 μM, respectively.     

Effects of in vitro exposure to ozone and/or hyperoxia on superoxide dismutase, catalase, glutathione and lipid peroxidation in red blood cells and plasma of rainbow trout, Oncorhynchus mykiss (Walbaum)

In aquaculture, ozone is used as a disinfectant. In its production, extensive amounts of oxygen are formed resulting in hyperoxic conditions in culture units. Both ozone and hyperoxia have the potential to be toxic via pro‐oxidant mechanisms and to activate antioxidant defence systems in cultured species. To eliminate systemic effects, blood of rainbow trout, Oncorhynchus mykiss (Walbaum), was exposed in vitro for 5 min to ozone/hyperoxia or hyperoxia, and changes in antioxidant defences and lipid peroxidation were measured after exposure. Ozone exposure caused severe damage in red blood cells (rbc) detected as increased lipid peroxidation and oxidized glutathione (GSSG) levels in both plasma and rbc. Oxygen exposure alone increased intracellular lipid peroxidation and GSSG levels 10 min after exposure and was not evident in the plasma at any time. Ozone, but not oxygen exposure, decreased reduced glutathione (GSH) levels in plasma, and the changes were negatively correlated with increased lipid peroxidation in rbc, indicating that extracellular GSH has a dynamic role in the protection of rbc from direct oxidation by ozone. Both ozone and hyperoxic conditions increased superoxide dismutase (SOD) activity in rbc 3 and 6 h after exposure. In contrast, catalase activity was only increased 10 min after oxygen exposure, suggesting other catalase activation mechanisms rather than enzyme induction. The recovery of lipid peroxidation and GSSG levels in rbc after hyperoxia, but not ozone exposure, indicated a capacity to defend against hyperoxia‐produced oxidative damage, but an overwhelming of antioxidant defences by ozone in rainbow trout rbc in vitro.     

Oxidation of glutathione during hydroperoxide metabolism in isolated hepatocytes of rainbow trout (Salmo gairdneri)

Freshly isolated rainbow trout hepatocytes were exposed to tert-butyl hydroperoxide (BuOOH), a substrate for glutathione peroxidase. BuOOH at a concentration approximately equimolar (1 mM) with intracellular reduced glutathione (GSH) caused a reversible increase in intracellular glutathione disulphide (GSSG) but did not compromise cell viability or damage membrane lipids. BuOOH at 10 mM caused a large irreversible increase in intracellular GSSG followed by efflux into the medium. Considerable leakage of lactate dehydrogenase and loss of highly unsaturated fatty acids, particularly docosahexaenoic acid also occurred. Dependence of hydroperoxide removal on flux through the hexose monophosphate pathway was suggested by the increased release of ¹⁴CO₂ from [1-¹⁴C] glucose from hepatocytes incubated with BuOOH.     

磷脂氢谷胱甘肽过氧化物酶在精子发育中的作用研究进展

磷脂氢谷胱甘肽过氧化物酶(PHGPx)是广泛存在于哺乳动物细胞内唯一能够物接还原生物膜上脂类过氧化物的一类含硒酶.该酶在保护细胞膜完整、维持细胞的正常功能中发挥着重要作用;同时PHGPx还作为精子的结构物质,在精子的发育和成熟过程中发挥着重要作用;精液中PHGPx活性是评价精液品质的重要参数之一.对PHGPx的基因结构、体内分布以及与精子发育与成熟相关的生物学特性和功能等研究进展进行了总结.     

Alteration of glutathione S-transferase properties during the development of <Emphasis Type="Italic">Micromelalopha troglodyta</Emphasis> larvae (Lepidoptera: Notodontidae)

Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.     

半边旗提取物6F对HL-60细胞还原型谷胱甘肽(GSH)水平的影响

目的：观察半边旗提取物6F对HL—60细胞内还原型谷胱甘肽(GSH)水平的影响，从氧化机测探讨其抗肿瘤作用的机哩。方法：用邻苯二醛(OPT)荧光分光度法测定细胞内还原型谷胱甘肽．结果：58至231nmol/L 6F作用细胞20h及231nmol/L 6F作用细胞6至24h，HL—60细胞内GSH含量均明显降低，呈明显的时间剂量效应关系。结论：化合物6F可降低HL—60细胞内还原型谷胱甘肽水平，推测通过细胞内氧化机制杀伤HL—60细胞并诱导其细胞凋亡是化合物6F抗肿瘤作用机测之一．