感染白粉病后不同葡萄品种的一些酶活性变化

植物受到病原菌侵染或被诱导处理后能产生一些诱导型抗病物质的合成或直接作用于病原菌的酶类和抗病酚类物质,利用这特性研究葡萄对白粉病的抗性.16个不同的葡萄品种接种白粉病后,测定POD、PPO、PAL等三种酶的酶活性差异,结果发现,接种白粉病后葡萄叶片三种酶活性水平均有提高,其中POD酶活性变化较PPO和PAL明显,PPO...     

间歇性低氧训练对大鼠心肌、骨骼肌有氧代谢酶与运动能力的影响研究

本实验借助于动物模型,探讨间歇性低氧训练后心肌和骨骼肌有氧代谢酶的变化与运动能力的关系。实验结果显示:经低氧训练后,大鼠心肌和骨骼肌的线粒体氧化酶SDH和CCO活性明显高于平原对照组和平原训练组,低氧训练后的大鼠运动时间延长。提示心肌和骨骼肌有氧代谢酶活性增高是提高有氧运动能力的重要物质基础。     

Piper sarmentosum as an antioxidant on oxidative stress in human umbilical vein endothelial cells induced by hydrogen peroxide

Endothelial cell death due to increased reactive oxygen species(ROS) may contribute to the initial endothelial injury,which promotes atherosclerotic lesion formation.Piper sarmentosum(PS),a natural product,has been shown to have an antioxidant property,which is hypothesized to inhibit production of ROS and prevent cell injury.Thus,the present study was designed to determine the effects of PS on the hydrogen peroxide(H2O2)-induced oxidative cell damage in cultured human umbilical vein endothelial cells(HUVECs).In this experiment,HUVECs were obtained by collagenase perfusion of the large vein in the umbilical cord and cultured in medium M200 supplemented with low serum growth supplementation(LSGS).HUVECs were treated with various concentrations of H2O2(0-1000 μmol/L) and it was observed that 180 μmol/L H2O2 reduced cell viability by 50% as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay.Using the above concentration as the positive control,the H2O2-induced HUVECs were concomitantly treated with various concentrations(100,150,250 and 300 μg/ml) of three different extracts(aqueous,methanol and hexane) of PS.Malondialdehyde(MDA),superoxide dismutase(SOD),catalase(CAT) and glutathione peroxidase(GPX) levels showed a significant increase(P0.05) in HUVECs compared to the negative control.However,PS extracts showed a protective effect on HUVECs from H2O2-induced cell apoptosis with a significant reduction in MDA,SOD,CAT and GPX levels(P0.05).Furthermore,PS had exhibited ferric reducing antioxidant power with its high phenolic content.Hence,it was concluded that PS plays a beneficial role in reducing oxidative stress in H2O2-induced HUVECs.     

仙人掌中黄酮类化合物的光谱分析及抗氧化性能测定

采用超声波法从仙人掌中提取黄酮类化合物,并用流动注射化学发光法测定了仙人掌的抗氧化性能.结果：方法的回收率为94.0%~109.0%,变异系数小于0.30%.测得仙人掌中黄酮化合物的含量为1.53 mg/g,仙人掌的IC50为1.38 mg/mL.结果表明,仙人掌的黄酮含量较高且具有较强的抗氧化性能.     

二氧化硫对玉米细胞保护酶同工酶的影响

采用同工酶电泳技术,研究SO2对玉米细胞保护酶同工酶的影响,结果表明,SO2对不同的玉米细胞保护酶有不同程度的影响,其中对CAT的影响最为明显.玉米细胞保护酶特别是CAT在SO2对玉米的伤害和玉米对SO2的抗性中可能具有重要的作用.     

亚硒酸钠对高温胁迫下梨苗部分酶活性的影响

用1．0mg．L~(-1)亚硒酸钠预先处理梨叶片,4d后用高温胁迫,5h后开始测定各种指标．结果表明,经亚硒酸钠处理的梨叶片愈创木酚过氧化物酶(GPX)、谷胱甘肽还原酶(GR)和过氧化物酶(POD)活性提高,脂氧合酶(LOX)活性下降．     

等离子体技术在固定化酶载体材料中的应用

等离子体技术作为材料表面改性的一种手段，可以赋予材料表面各种性能。以等离子体处理的载体材料固定化酶，开拓了固定化酶技术的新领域。本综述了用等离子体技术处理载体材料进行固定化酶的最新进展，并展望了其发展前景。     

A non-invasive approach to differential diagnosis of urinary tract infections using lactate dehydrogenase isoenzyme profile,N-acetyl-β-D-glucosaminidase and alanine aminopeptidase

Lactate dehydrogenase (LDH) and its isoenzyme profile, Nacety-β-d-glucosaminidase (NAG) and alanine aminopeptidase (AAP) enzyme activities were measured in 21 cases with well documented acute untreated urinary tract infections (UTI) and compared with a group of 68 normal healthy subjects matched for age and sex. Urinary NAG, AAP and LDH total activities were highly elevated (3–30 fold for NAG, 2–10 fold for AAP and 2–50 fold for LDH over upper limit of normal) in upper tract infections. In lower tract infections there was a marginal elevation in NAG and LDH while AAP activity was very high; though there was no overlap. Further, the isoenzyme profile of LDH showed predominance of LD-5 isoenzyme in all cases of pyelonephritis, while it was completely absent in all the cases of lower tract infections. We conclude that urinary NAG and LDH-5 isoenzyme would serve as specific non-invasive parameters for differential localization of urinary tract infections.     

Effect ofCrataeva nurvala bark decoction on enzymatic changes in liver of normal and stone forming rats

The influence of Crataeva nurvala bark decoction was studied in calcium oxalate stone forming rats, in relation to oxalate metabolism in liver. The activities of the major oxalate synthesizing enzymes in liver namely, glycollate oxidase (GAO) and lactate dehydrogenase (LDH) were significantly increased in the calculogenic group. Bark decoction treatment lowered the liver GAO activity considerably. Transport ATPases (Na⁺, K⁺ and Ca²⁺-ATPases) and alkaline phosphatase were enhanced in rats fed calculi producing diet, while the activities of acid phosphatase, inorganic pyrophosphatase and aminotransferases were slightly reduced. Bark decoction administration produced a marginal decrease in Na⁺, K⁺-ATPase and increase in aspartate aminotransferase activities, without significantly altering other enzyme activities. The decrease in liver GAO activity seen during bark decoction treatment, with concomitant decrease in kidney oxalate level, may prove beneficial as a prophylactic measure in preventing stone recurrence.     

Picrotoxin-induced convulsions and lysosomal function in the rat brain

The effect of picrotoxin-induced convulsions on lysosomal function in rat brain were evaluated by measuring the free as well as total acid phosphatase, cathepsin D, acid ribonuclease (RNAse II) and acid deoxyribonuclease (DNAse II) activities. Following picrotoxin treatment the free RNAse II activity increased whereas the total activities of practically all the other enzymes decreased. Paradoxically, the cathepsin D activity, free as well the total was completely abolished. In case of all the enzymes the ratio of Total activity/Free activity decreased indicating increased lysosomal membrane fragility which could lead to process of neurodegeneration in the epileptic animals.