小麦叶片硝酸还原酶抑制蛋白的制备及其作用研究

通过40%～70%饱和硫酸铵分级分离和SephadexG-75柱层析,得到纯化101 6倍的小麦叶片硝酸还原酶抑制蛋白,在室温及中性环境下对硝酸还原酶活力有明显的抑制作用。小麦叶片硝酸还原酶抑制蛋白是与硝酸还原酶可逆结合发挥作用的,是硝酸还原酶的竞争性抑制剂。     

水稻高产优质高效栽培的基础生理研究

本文对双季稻高产优质高效栽培途径与传统栽培法的生理基础进行了比较研究。结果表明,采用“双高一优”法栽培,水稻根系特别发达,对氮、磷、钾的吸收能力及根系过氧化物酶活力均明显优于对照;功能叶的碳氮同化协调,呼吸消耗少,谷粒灌浆启动快,速率大;尤以以下三方面的结果更具有意义。(1) 水稻每克鲜根的氧化力低于对照17.5%—36.1%。(2) 叶片的叶绿素b含量及叶绿素溶液在430nm附近的O.D值分别比对照高49%—68%,67%—106%,剑叶透光率较对照低22.2%。(3) 功能叶及根系的硝酸还原酶活力比对照低,表现出与高产耐肥品种一样的生理特性。此外,本文还对根系活力及其与土壤环境的关系,作物根系及田间杂草对改良土壤、提高地力的作用,提出了新的看法。     

猕猴桃果实L-半乳糖内酯脱氢酶和脱氢抗坏血酸还原酶cDNA片段的克隆与序列分析

克隆猕猴桃果实L-半乳糖内酯脱氢酶(GalLDH)和脱氢抗坏血酸还原酶(DHAR)基因,可为揭示猕猴桃高抗坏血酸(AsA)含量的分子机制奠定基础。研究以猕猴桃果实为材料提取总RNA,采用RT-PCR法,克隆出L-GalLDH基因的cDNA片段857 bp和DHAR基因的cDNA片段594 bp并测序,根据测序结果推测其氨基酸序列,并与刺梨、拟南芥、花椰菜、甘薯和草莓等植物的GalLDH基因和DHAR基因氨基酸序列进行亲缘分析。结果表明,猕猴桃GalLDH基因氨基酸序列和核苷酸序列与刺梨的相似性高达88%,其在同源基因进化关系树中单独聚为一类;DHAR基因氨基酸序列和核苷酸序列与苹果的相似性高达98%和99%,两者在进化关系上聚为一类。可知克隆到的2个核苷酸片段确为猕猴桃L-GalLDH和DHAR基因cDNA片段,同源基因植物亲缘关系聚类与传统的形态分类有一定的差异。     

茶树花色素还原酶基因的克隆与原核表达

采用RACE技术,从茶树新品系"1005"的嫩芽中克隆出ANR基因的全长cDNA(1260 bp),其推导的氨基酸序列与茶树、葡萄花色素还原酶的一致性分别为99%和84%;并成功构建了ANR基因的原核表达载体pET-ANR,在大肠杆菌BL21中表达出预期大小(约45 ku)的融合蛋白.     

杂交水稻氮素代谢特性的研究(英文)

研究结果表明,在分蘖、孕穗和抽穗期,供试杂交稻组合的功能叶片中的氮浓度、可溶性蛋白质和叶绿素含量明显高于常规稻.在其氮素代谢过程中,NR,GS,Fd-GOGAT,GPT和GOT酶活力,在供试品种间的差异是:汕优64>汕优6号>浙丽1号>秀水48,氮素营养条件的变化对此差异无影响,在杂变稻与常规稻之间,Fd-GOGAT酶活力和NR酶活力差异最大(分别达到50～70％和40～70％),而GPT酶活的差异较小.结果还表明,在不同水稻品种的功能叶中,上述5种酶的活力,与叶中可溶性蛋白质含量及全氮量均呈积显著正相关,这说明在杂交稻叶片中,氮素同化和蛋白质合成的酶系统,其活力优于常规稻的该酶系统,它们是杂交稻吸收利用氮素能力强的重要生理基础之一.     

Tissue-specific enhancement of xenobiotic detoxification enzymes in mice by dietary rosemary extract

Plant foods contain nutritive and minor, nonnutritive components capable of inhibiting experimental carcinogenesis. Many of these cancer-protective extracts act by enhancing the activities of enzymes that can detoxify reactive substances. In the present study an extract of the spice plant rosemary was fed at concentrations of 0.3% and 0.6% (by weight) for 4 weeks to female A/J mice prior to determination of the activities of the detoxification enzymes glutathione-S-transferase (GST) and NAD(P)H: quinone reductase (QR) in lung, liver and stomach. Liver activities of GST and QR, and stomach GST activity were significantly increased in animals fed diets containing rosemary extract. However, diets supplemented with rosemary extract did not affect lung GST and QR activities. These results indicate that components of rosemary extract have the potential to protect mouse liver and stomach from carcinogenic or toxic agents.     

几种海洋微藻硝酸还原酶特性的初步研究

确定了离体法提取时间,并采用离体法对5种海洋微藻硝酸还原酶的特性进行了初步研究。结果表明,离体法的最佳提取时间为5min;在pH7.9及20℃条件下,各藻硝酸还原酶的酶促反应恒速时间及以KNO3为底物的米氏常数存在差异,但以NADH为底物的米氏常数基本相同。酶促反应恒速时间顺序为锥状斯氏藻<尖刺拟菱形藻<东海原甲藻<中肋骨条藻<旋链角毛藻,以KNO3为底物的米氏常数大小顺序为旋链角毛藻<东海原甲藻~中肋骨条藻<锥状斯氏藻~尖刺拟菱形藻。此外,FAD对各藻硝酸还原酶活性的影响存在种属差异。     

Disease resistance and hypocholesterolemia in yellowtail Seriola quinqueradiata fed a non-fishmeal diet

ABSTRACT:   The physiology of yellowtail fed a non-fishmeal diet was examined, with a specific interest in the role of taurine in disease resistance and cholesterol metabolism. Decrease of disease resistance in fish fed a non-fishmeal diet was confirmed by mortality due to natural infection with pseudotuberculosis and artificial infection with Lactococcus garvieae . It is suggested that the most important symptoms related to decrease of disease resistance in fish fed a non-fishmeal diet is anemia. Anemia was improved by supplementation with taurine. Significant elevation of relative expression of HMG-CoA reductase mRNA in fish fed a non-fishmeal diet suggests that cholesterol synthesis would be activated and not dysfunctional. Plasma cholesterol of these fish was elevated to the levels of control fish by supplementation of both cholesterol and taurine. These results suggest that hypocholesterolemia observed in fish fed a non-fishmeal diet compared with a fishmeal diet would be caused by insufficient dietary cholesterol and decrease of endogenous cholesterol due to the lack of dietary taurine.     

光照和不同形态氮营养盐供应对坛紫菜硝酸还原酶活性的影响

光照和不同形态氮营养盐供应对坛紫菜硝酸还原酶活性的影响=Effect of light and different forms of nitrogen on the activity of nitrate reductase of Porphyra haitanensis (Rhodophyta)［刊,中］/徐智广（汕头大学海洋生物研究所,汕头515063),邹定辉,张鑫,刘树霞,高坤山//水产学报,—2007,31(1).-90～96 为了探讨光照、NO3-N和NH4+N对坛紫菜（Porphyra haitanensis）硝酸还原酶活性（NRA）的影响,在光照和黑暗条件下分别对坛紫菜叶状体进行氮（N）饥饿→氮（N）加富和N加富→N饥饿处理,并测定NRA的变化。结果表明：在N饥饿→N加富过程中,光照下NRA比黑暗中要高;NO3-N的加富能提高NRA,且在光照下比黑暗中NRA达到最大值的时间要短;而NH4+N与NO3-N共同对N饥饿藻体加富时NRA没有明显变化,并与NH4+N单独加富无显著差异。另外,对于N加富→N饥饿的处理,在光照下NO3-N加富和NH4+N与NO3-N共同加富的NR都能在N饥饿处理后的一段时间内维持较高的活性。这些结果说明：光照和硝酸盐对NRA起正调节作用,而铵盐对NRA起负调节作用,但NRA与体外硝酸盐浓度并不成直接的正相关关系。图4参24 关键词：坛紫菜;硝酸还原酶活性; 氮饥饿; 氮加富; 光照; 营养盐 E-mail：dhzou@stu.edu.cn