中国人群eNOS基因内含子13微卫星多态性的初步研究

目的：为研究ｅＮＯＳ基因内含子１３上的微卫星序列与妊高症的相关性。方法：采用ＰＣＲ－ＰＡＧＥ与银染相结合的方法，研究其多态性。结果：得到含有该微卫星序列的ＤＮＡ片段。结论：证实在中国人群中ｅＮＯＳ基因内含子１３上的确存在一个ＣＡ重复的多态性微卫星序列，从而为研究该位点与妊高病的相关性提供了技术支持和理论依据。     

一氧化氮吸入对缺氧性肺动脉高压患者一氧化氮合酶和内皮素的影响

探讨吸入一氧化氮（ＮＯ）对缺氧性肺动脉高压患者一氧化氮合酶（ＮＯＳ）和内皮素（ＥＴ）的影响。方法：１３例肺动脉高压患者行ＮＯ吸入，分别于吸入ＮＯ前、吸入３０ｍｉｎ时、停止吸入２ｈ和１２ｈ时采肺动脉血，测白细胞中的ＮＯＳ及血浆中的ＥＴ。结果：吸入ＮＯ前、吸入３０ｍｉｎ时、停止吸入２ｈ和１２ｈ，所测ＮＯＳ值分别为（０７０±０．２１）ｍｏｌ／ｍｉｎ·ｍｇ－１、（０７４±０１４）ｍｏｌ／ｍｉｎ·ｍｇ－１、（０６４±０２２）ｍｏｌ／ｍｉｎ·ｍｇ－１和（０６３±０１７）ｍｏｌ／ｍｉｎ·ｍｇ－１；所测ＥＴ为（７８８９±４６５９）ｐｍｏｌ／Ｌ、（８８２７±４５４１）ｐｍｏｌ／Ｌ、（８０７６±４２６６）ｐｍｏｌ／Ｌ和（６１０７±２９．４４）ｐｍｏｌ·Ｌ－１；后三者同吸入前比，均Ｐ＞００５。结论：缺氧性肺高压患者吸入ＮＯ对机体ＮＯＳ和ＥＴ未见明显影响     

暗纹东方鲀线粒体ATPase8和ATPase6基因的克隆与序列分析

克隆并测定了暗纹东方鲍（Takifugu fasciatus）线粒体ATP合酶Fo亚基8（ATPase8）和亚基6（ATPase6）的序列,并对其进行了初步分析。结果表明：PCR扩增产物的总长度为923bp,其中842bp为ATP8和ATP6基因的编码区。ATP8基因长168bp,编码55个氨基酸残基的蛋白质,其蛋白分子质量为6．8KD,等电点为7．85;ATP6基因长684bp,编码227个氨基酸残基的蛋白质,其蛋白分子质量为24．9KD,等电点为9．16。暗纹东方纯ATP合酶Fo亚基8和亚基6与其他已报道的部分东方纯属鱼类具有很高的同源性。通过探讨ATP合酶F0亚基所含的信息量,发现相对于其他线粒体基因,ATPase8和ATPase6基因所含鉴别信息较少。     

大白鼠海马神经元NOS与AChE活性的研究

目的:观察大白鼠海马不同亚区一氧化氮合酶(NOS)与乙酰胆碱酯酶(AChE)阳性神经元的活性。方法:分别采用还原型尼克酰胺嘌呤二核苷酸脱氢酶(NADPH-d)和乙酰胆碱酯酶(AChE)组织化学方法对大白鼠海马不同亚区NOS和AChE阳性神经元的分布以及活性进行研究。结果:海马不同亚区均含有NOS和AChE阳性神经元,其中CA2区NOS呈强阳性反应,CA3区AChE呈强阳性反应。结论:实验表明,NOS和AChE阳性神经元广泛分布于大白鼠海马不同亚区,为进一步探讨海马的学习记忆功能机制提供了形态学佐证。     

太极拳锻炼对中老年人血清NO含量和NOS活性的影响

对长期坚持太极拳锻炼的中老年人血清NO含量及NOS活性进行测定.结果显示:(1)长期规律的太极拳锻炼可以纠正和延缓中老年人因增龄引起的血清NO含量下降,从而预防心血管疾病的发生;(2)长期规律的太极拳运动明显增强老年人血清NOS的活性,进而增加NO的合成.     

氯化钴对人eNOS基因启动子转录活性的影响

目的:建立氯化钴诱导的人脐静脉血管内皮细胞-12(HUVEC-12)缺氧模型,研究人血管内皮细胞一氧化氮合酶(eNOS)基因的启动子活性变化.方法:用含不同浓度氯化钴的培养基培养细胞,检测细胞培养上清中的乳酸脱氢酶(LDH)含量;将已构建的pGL2-eNOS-p质粒转染HUVEC-12细胞,利用双荧光素酶报告基因技术检测在不同浓度氯化钴和不同作用时间下的eNOS启动子转录活性.结果:氯化钴刺激下HUVEC-12细胞培养上清的LDH含量随氯化钴作用浓度增加而提高;氯化钴刺激后转染细胞的eNOS启动子活性呈现随氯化钴剂量增加而升高的趋势,随作用时间的延长而上升的趋势.结论:成功建立氯化钴诱导HUVEC-12细胞缺氧的体外模型.     

大别山区葛根黄酮对四氧嘧啶糖尿病模型小鼠糖脂代谢的影响

为研究葛根黄酮(RPF)对糖尿病模型小鼠糖脂代谢的影响及其可能的作用机制,采用四氧嘧啶(ALX,220mg/kg)腹腔注射建立糖尿病小鼠模型。RPF连续灌胃15d后摘眼球取血,分离血清,测定血糖、血清甘油三酯(TG)、总胆固醇(TC)、一氧化氮(NO)和一氧化氮合酶(NOS)水平;取肝、肾脏制成10%匀浆测定其NO和NOS水平;观察胰腺病理学形态变化。结果显示RPF能降低ALX诱导的糖尿病模型小鼠血糖、血清和肝脏中NO和NOS。其降糖机制可能与降低血清、肝脏的NO和NOS水平有关。     

Insights into the subunit interactions of the chloroplast ATP synthase

Subunit interactions of the chloroplast F0F1- ATP synthase were studied using the yeast two-hybrid system. The coding sequences of all the nine subunits of spinach chloroplast ATP synthase were cloned in two-hybrid vectors. The vectors were transformed into the yeast strains HF7c and SFY526 by various pairwise combinations, and the protein interactions were analyzed by measuring the yeast growth on minimal SD medium without serine, lucine and histidine. Interactions of γ Subunit with wild type or two truncated mutants of γ sununit, △εN21 and △εC45, which lose their abilities to inhibit the ATP hydrolysis, were also detected by in vitro and in vivo binding assay. The present results are largely accordant to the common structure model of F0F1-ATP synthase. Different from that in the E. Coli F0F1-ATP synthase, the δ subunit of chloroplast ATP syn- thase could interact with β,γ,ε and all the CF0 subunits in the two-hybrid system. These results suggested that though the chloroplast ATP synthase shares the similar structure and composition of subunits with the enzyme from E. Coli, it may be different in the subunit interactions and con- formational change during catalysis between these two sources of ATP synthase. Based on the present results and our knowledge of structure model of E. Coli ATP synthase, a deduced structure model of chloroplast ATP synthase was proposed.     

Glutamate synthase: a fascinating pathway from L-glutamine to L-glutamate

Glutamate synthase is a multicomponent iron-sulfur flavoprotein belonging to the class of N-terminal nucleophile amidotransferases. It catalyzes the conversion of L-glutamine and 2-oxoglutarate into two molecules of L-glutamate. In recent years the X-ray structures of the ferredoxin-dependent glutamate synthase and of the a subunit of the NADPH-dependent glutamate synthase have become available. Thanks to X-ray crystallography, it is now known that the ammonia reaction intermediate is transferred via an intramolecular tunnel from the amidotransferase domain to the synthase domain over a distance of about 32Å. Although ammonia channeling is a recurrent theme for N-terminal nucleophile and triad-type amidotransferases, the molecular mechanisms of ammonia transfer and its control are different for each known amidotransferase. This review focuses on the intriguing mechanism of action and self-regulation of glutamate synthase with a special focus on the structural data.Received 8 August 2003; received after revision 15 September 2003; accepted 17 September 2003