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。     

一氧化氮合酶在猕猴中枢神经系统中的表达

研究神经元型一氧化氮合酶(NOS1)在灵长类动物中枢神经系统中的表达．方法：采用免疫组织化学技术，观察了一氧化氮合酶在正常猕猴脑和脊髓中的表达．结果表明NOS1阳性神经元分布于中枢神经系统的广泛区域，包括大脑皮质、海马、齿状回、尾壳核、纹状体、小脑皮质、脊髓前角、后角和中央灰质与中枢神经系统的诸多功能有关．     

吡啶羧酸铬对肥育猪皮下脂肪组织脂肪酸合成酶mRNA表达的影响

选用体重58 kg左右的斯格×斯格×杜洛克三元杂交肥育猪48头,按试验要求分成2组,每组3个重复,分别饲喂添加0、200 μg/kg吡啶羧酸铬的玉米-豆粕型饲粮.结果表明,吡啶羧酸铬能明显改善肥育猪的胴体组成,胴体瘦肉率提高了6.1%(P＜0.05),眼肌面积增大了13.4%(P＜0.05),胴体脂肪率和平均背膘厚分别降低了13.5%(P＜0.05)、11.1%(P＜0.05);皮下脂肪组织FAS mRNA丰度减少了23.9%(P＜0.05),FAS活性降低了19.4%(P＜0.05).提示吡啶羧酸铬可通过降低肥育猪皮下脂肪组织FAS的mRNA表达及其活性,从而减少脂肪沉积,改善胴体组成.     

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。     

代谢工程方法改造谷氨酸棒状杆菌生产乙偶姻

应用代谢工程方法对Corynebacterium glutamicum ATCC 13032生物合成乙偶姻进行了研究.在C.glutamicum ATCC 13032中导入了Bacillus subtilis 168的乙偶姻合成途径的相关基因als SD操纵子,工程菌株的乙偶姻产量为2.14,g/L.为了增加合成乙偶姻的直接前体物丙酮酸的供给,进一步敲除了丙酮酸脱氢酶复合体E1亚基的编码基因(ace E)和乳酸脱氢酶基因(ldh A),工程菌株的乙偶姻产量提高到5.09,g/L.最后,敲除了工程菌株的2,3-丁二醇脱氢酶基因(but A)以阻断副产物2,3-丁二醇的合成,在优化的溶氧条件下,菌株CGL3在基本培养基中乙偶姻产量提高到8.33,g/L,达到理论得率的51.5%.实验结果表明经过代谢工程改造的C.glutamicum ATCC 13032具有良好的乙偶姻合成能力和应用潜力.     

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     

Glutamate synthase: a complex iron-sulfur flavoprotein

Glutamate synthase is a complex iron-sulfur flavoprotein that forms l-glutamate from l-glutamine and 2-oxoglutarate. It participates with glutamine synthetase in ammonia assimilation processes. The known structural and biochemical properties of glutamate synthase from Azospirillum brasilense, a nitrogen-fixing bacterium, will be discussed in comparison to those of the ferredoxin-dependent enzyme from photosynthetic tissues and of the eukaryotic reduced pyridine nucleotide-dependent form of glutamate synthase in order to gain insight into the mechanism of the glutamate synthase reaction. Sequence analyses also revealed that the small subunit of bacterial glutamate synthase may be the prototype of a novel class of flavin adenine dinucleotide- and iron-sulfur-containing oxidoreductase widely used as an enzyme subunit or domain to transfer reducing equivalents from NAD(P)H to an acceptor protein or protein domain. Received 10 November 1998, received after revision 10 December 1998; accepted 10 December 1998     

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。     

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     

Genetic functional inactivation of neuronal nitric oxide synthase affects stress-related Fos expression in specific brain regions

To identify neuronal substrates involved in NO/stress interactions we used Fos expression as a marker and examined the pattern of neuronal activation in response to swim stress in nNOS knock-out (nNOS–/–) and wild-type (WT) mice. Forced swimming enhanced Fos expression in WT and nNOS–/– mice in several brain regions, including cortical, limbic and hypothalamic regions. Differences in the Fos response between the two groups were observed in a limited set (6 out of 42) of these brain areas only: nNOS–/– mice displayed increased stressor-induced Fos expression in the medial amygdala, periventricular hypothalamic nucleus, supraoptic nucleus, CA1 field of the hippocampus, dentate gyrus and infralimbic cortex. No differences were observed in regions including the septum, central amygdala, periaqueductal grey and locus coeruleus. During forced swimming, nNOS–/– mice displayed reduced immobility duration, while no differences in general locomotor activity were observed between the groups in the home cage and during the open field test. The findings indicate that deletion of nNOS alters stress-coping ability during forced swimming and leads to an altered pattern of neuronal activation in response to this stressor in specific parts of the limbic system, hypothalamus and the medial prefrontal cortex.Received 29 March 2004; accepted 21 April 2004