Organic solvents enhanced spectrofluorimetric method for determination of laccase activity

A novel fluorimetric method for determination of laccase activity in organic solvents is proposed, based on the oxidation ofo-phenylenediamine (1,2-diaminobenzene, OPDA) catalyzed by laccase yielding 2,3-diaminophenazine. The optimal conditions for laccase in organic media areT=55°C, pH=6.5, 1.0×10⁻²mol/L OPDA, 1.25 mL ethanol, 1.25 mL 1,4-dioxane and 1.25 mL acetone. The linear range of the method proposed in ethanol, 1,4-dioxane and acetone media were 0.44–19.33, 0.11–20.85, 0.38–21.05 U with the detection limit of 0.088, 0.022, 0.076 U, respectively. The proposed method has been applied to the analysis of laccase activity of real samples with more accurate and sensitive than that of the previous method reported. Supported by the National Natural Science Foundation of China and the Special Founds of State Education Committee for Doctorate Research Huang Zuyun: born in 1963, Ph.D     

大蒜超氧化物歧化酶活性测定及某些性质研究

采用肾上腺素自氧化法对蒜头ＳＯＤ进行活力测定及某些性质研究。结果表明：蒜头粗提取液富含ＳＯＤ，其比活力为４．６０２×１０４ｕ／ｇ蛋白质；它在３０～６５℃及ｐＨ５～ｐＨ９时活力较强；用ＰＡＧＥ分离出两条酶带；能被高浓度的ＫＣＮ、Ｈ２Ｏ２完全抑制，但对氯仿－乙醇液不敏感，说明此酶为Ｃｕ、Ｚｎ－ＳＯＤ。     

无限稀活度系数与选择性分子间引力

本文采用气相色谱法测定了十余种不同溶质在聚乙二醇-400和邻苯二甲酸二壬酯上的无限稀活度系数。应用“选择性分子间引力”的理论,对实验结果进行了理论探讨。     

炸干茸与冻干茸中超氧化物歧化酶活力测定

采用改进的邻苯三酚法测得的炸干茸和冻干茸中超氧化物歧化酶的活力,分别为2400μmol/(min·g)和4880μmol/(min·g),探讨了用超氧化物歧化酶活力作为判定鹿茸的质量指标,以及鹿茸加工工艺是否合理的参考依据之一的可能性。     

Na~+-K~+-Cl~--Br~-水溶液体系中活度系数的测定与计算

用离子选择性电极测定了 ＮａＣ１、 ＫＣ１、 ＫＢｒ、 ＮａＣ１－ＫＣ１、 ＫＣ１－ＫＢｒ和ＮａＣ１－ＫＢｒ水溶液中的电动势，温度为 １０、 ２５、 ３５和 ４５℃，从而求出在上述３个混合电解质溶液中 ＫＣ１、 ＮａＣ１和 ＫＢｒ的活度系数，并将自行改进的 Ｐｉｔｚｅｒ－Ｌｉ方程用于此混合电解质溶液，取得了良好的结果。     

几种离子通道阻断剂对豚鼠离体小肠电活动与收缩活动的影响

本文报告离子通道阻断剂河豚毒素、四乙胺、异博定、硝普钠对豚鼠离体小肠电活动与收缩活动的影响。结果显示:河豚毒素、四乙胺、异博定、硝普钠均不同程度地抑制动作电位与肠肌张力,其中对动作电位的抑制作用是四乙胺>异博定>河豚毒素>硝普钠;对肠肌张力的抑制,在环行肌其抑制作用是河豚毒素>四乙胺>异博定>硝普钠,在纵行肌则是异博定>河豚毒素>硝普钠>四乙胺,这一结果提示:动作电位的形成与Na~+、K~+、Ca~(2+)的跨膜运动均有一定关系,而环肌与纵肌收缩反应的差异可能与肌细胞膜上离子通道的分布和敏感性不同有关。     

Interdependence between locomotor activity and duration of wakefulness in humans during isolation

Summary Locomotor activity was recorded in 14 subjects who lived singly in an isolation unit for 16 to 88 days. Their free-running circadian rhythms had a mean period of 25.9 h, with individual means in the duration of wakefulness () ranging from 12.1 to 22.9 h. Intraindividually, the hourly means of activity were negatively correlated with to such a degree that the total amount of activity per day remained constant irrespective of large variations in .     

Biological activity of enantiomerically pure forms of insect juvenile hormone I and III inBombyx mori

Summary Biological activity of enantiomerically pure juvenile hormones was assayed by topical application on allatectomizedBombyx fourth instar larvae. JHs tested were (10R)-JH I [methyl (2E,6E,10R,11S)-10,11-epoxy-3,11-dimethyl-7-ethyl-2,6-tridecadienoate], (10S)-JH I [methyl (2E, 6E, 10S, 11R)-10,11-epoxy-3,11-dimethyl-7-ethyl-2,6-tridecadienoate], (10R)-JH III [methyl (2E,6E,10R)-10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate] and (10S)-JH III [methyl (2E,6E,10S)-10,11-epoxy-3,7,11-trimethyl-2,6-dodecadienoate]. Among these compounds, natural (10R)-JH I was most active and the dose needed to induce 50% larval molting was 0.04 g/larva; it was approximately 12,000 times more active than unnatural (10S)-JH I. Though natural (10R)-JH III showed slight biological activity, it was only one three-thousandth of that of (10R)-JH I. Unnatural (10S)-JH III exhibited no biological activity at the levels assayed.