野生大豆(Glycine soja Sieb et ZUCC)球蛋白A_5 A_4 B_3 cDNA的研究(简报)

大豆球蛋白是大豆种子中主要的贮藏蛋白。它们在某些作物中占种子干重20%以上。已经知道大豆球蛋白由6个亚基组成。每个亚基由一或两个酸性多肽(A)和一个碱性多肽(B)组成,多肽之间由二硫键联结。这些亚基是从编码A-B亚基前体的mRNA合成,然后经过转录后加工剪切形成A肽和B肽。至今所有关于球蛋白的基因结构与表达的报道都集中于栽培大豆上。由于我国有丰富的大豆     

光镊探索DNA凝聚过程

自从20年前光镊技术被Ashkin、Chu及其同事发明[1],该技术已被应用于各种生物学研究并由此获得丰富信息.例如应力下生物高分子的行为[2],DNA连接酶如何译码或如何消化DNA[3～6],动力蛋白如何沿分子轨道移动[7～8],以及RNA和蛋白质分子如何折叠/展开[9～11].通过对单个分子的操纵,光镊技术可用于探索这些生物系统在分子层面的工作模式.在本期222页,Case等描述了该技术的另一精巧应用.揭示了凝聚子蛋白质如何产生紧凑形式的DNA[12].     

Comparative Fluxome and Metabolome Analysis of Formate as an Auxiliary Substrate for Penicillin Production in Glucose‐Limited Cultivation of Penicillium chrysogenum

During glucose‐limited growth, a substantial input of adenosine triphosphate (ATP) is required for the production of β‐lactams by the filamentous fungus Penicillium chrysogenum. Formate dehydrogenase has been confirmed in P. chrysogenum for formate oxidation allowing an extra supply of ATP, and coassimilation of glucose and formate has the potential to increase penicillin production and biomass yield. In this study, the steady‐state metabolite levels and fluxes in response to cofeeding of formate as an auxiliary substrate in glucose‐limited chemostat cultures at the dilution rates (D) of both 0.03 h^?1 and 0.05 h^?1 are determined to evaluate the quantitative impact on the physiology of a high‐yielding P. chrysogenum strain. It is observed that an equimolar addition of formate is conducive to an increase in both biomass yield and penicillin production at D = 0.03 h^?1, while this is not the case at D = 0.05 h^?1. In addition, a higher cytosolic redox status (NADH/NAD⁺), a higher intracellular glucose level, and lower penicillin productivity are only observed upon formate addition at D = 0.05 h^?1, which are virtually absent at D = 0.03 h^?1. In conclusion, the results demonstrate that the effect of formate as an auxiliary substrate on penicillin productivity in the glucose‐limited chemostat cultivations of P. chrysogenum is not only dependent on the formate/glucose ratio as published before but also on the specific growth rate. The results also imply that the overall process productivity and quality regarding the use of formate should be further explored in an actual industrial‐scale scenario.     

Syn-1A在抑制弱酸性pH诱导的KATP通道活化过程中的作用

目的：观察Syn-1A在抑制弱酸性pH诱导的KATP通道活化过程中的作用及机制。方法：用稳定表达Kir6.2/SUR2A KATP通道的HEK-293细胞构建细胞膜内面向外的记录方式,并给细胞膜片连续灌流含或不含Syn-1A的pH7.4,7.0,6.8,6.5和6.0的溶液,观察弱酸性pH对通道的活化作用及Syn-1A对上述作用的抑制,并采用体外结合实验分析不同pH对Syn-1A与SUR2A亚单位结合的影响。结果：Syn-1A可抑制pH 6.5,6.8和7.0时诱发的通道活化作用,Syn-1A与SUR2A的结合在pH7.4至6.0范围内,随pH下降逐渐增加。结论：Syn-1A对KATP通道的抑制作用可缓冲pH波动引起的KATP通道开放,从而抑制折返性心律失常的发生。     

苏州地区不同营养类型湖泊经济鱼体中金属元素含量水平的探讨

1984—1985年,对苏州地区不同营养类型湖泊9种经济鱼类中26种金属元素含量进行了测定和分析。①在湖泊中污染区的鱼体金属元素含量要比非污染区高。②鱼对金属元素的吸收、富集规律是:底层鱼>中层鱼>上层鱼;食物链长的鱼>食物链短的鱼(即肉食性鱼>杂食性鱼>草食性鱼);鱼鳃>鱼肉。③在相同的环境条件和生长状况下,鱼体中金属元素含量具有相对的稳定性;鱼在污染性湖泊中具有区域性分布的特点,因而鱼也是污染物的指示者之一。④苏州地区湖泊鱼体中金属元素的自然含量不太高,与苏联里海地区的鱼类相近似;它们在鱼体内的排列次序为:铁>锌>锶>铜>铅>钡>锂>铌>镓>镍>铈>钛>锰>钍>钴>铬>砷>汞>镉>钒>锆>钇>镧>铍≥镱>钼。     

催乳素对大鼠前列腺细胞合成酸性磷酸酶的作用及其机制的研究

本文利用无血清培养的末成年大鼠前列腺上皮细胞模型研究了催乳素(PRL)和性激素对前列腺细胞分泌前列腺特异的酸性磷酸酶(PAP)功能的作用,并对其作用途径进行了探讨。结果表明:PRL 显著促进前列腺细胞PAP的合成和分泌,但与双氢睾酮(DHT)或雌二醇(E_2)无协同作用,单独的DHT 或E_2对PAP 的合成和分泌也无显著作用。在PRL 的作用过程中,腺苷酸环化酶未活化;PRL 和前列腺素E_2或F_(2α)有协同作用,消炎痛能阻断PRL 的作用。综合实验结果,本实验证明了PRL 对前列腺细胞的分泌功能有直接的刺激作用,在PRL 的作用过程中,可能有前列腺素的参与。     

Comparative studies of LFA-1/ICAM-1 interaction by micropipette and flow chamber techniques

Interaction of lymphocyte function-associated antigen-1 (LFA-1) with intercellular adhesive molecule-1 (ICAM-1) is important in a number of cellular events, including inflammation, adhesion, transendothelial migration. The aim of this work was to study comparatively the adhesive interaction between LFA-1 and ICAM-1 by a micropipette technique and a flow chamber method, and also to explore the effects of tumor necrosis factor (TNF-alpha), phytohemagglutinin (PHA), and tetramethylpyrazine (TMP) on this interaction. The adhesion probability (Pa) between a lymphocyte cell line SKW-3 expressing LFA-1 and a red blood cell (RBC) coated with soluble ICAM-1 was approached by the micropipette technique, while the flow chamber allowed to observe the firm adhesion of SKW-3 on human umbilical vein endothelial cells (HUVECs). Experimental results show that PHA stimulation of lymphocytes resulted in significant increases in the adhesion probability (Pa) and in number of firmly adhered lymphocytes to HUVECs, but TMP treatment could significantly inhibit such increases.     

水稻Os着-c op 1基因的原核表达及多克隆抗体制备

着-COP蛋白是真核生物分泌途径中COP玉有被小泡的一个亚基。本研究利用PCR技术扩增水稻着-c op基因(Os着-c op 1)的ORF(开放阅读框),并克隆到原核表达载体pET-23d上,将表达载体pET-Os着-cop1转入大肠杆菌BL21(DE3),以1.0 mmol/L的IPTG (isopropylβ-D-thiogalactoside)诱导表达重组蛋白,然后以重组蛋白作为抗原免疫家兔,制备多克隆抗体。SDS-PAGE电泳分析结果表明,成功诱导表达了分子量约为35 kD的重组蛋白,Western blot检测表明,免疫家兔的抗血清与水稻幼穗总蛋白杂交信号较好。Os着-COP1抗体的制备有助于研究该基因及COPI小泡在水稻中的功能。     

An Accessory Agonist Binding Site Promotes Activation of α4β2* Nicotinic Acetylcholine Receptors

Neuronal nicotinic acetylcholine receptors containing α4, β2, and sometimes other subunits (α4β2* nAChRs) regulate addictive and other behavioral effects of nicotine. These nAChRs exist in several stoichiometries, typically with two high affinity acetylcholine (ACh) binding sites at the interface of α4 and β2 subunits and a fifth accessory subunit. A third low affinity ACh binding site is formed when this accessory subunit is α4 but not if it is β2. Agonists selective for the accessory ACh site, such as 3-[3-(3-pyridyl)-1,2,4-oxadiazol-5-yl]benzonitrile (NS9283), cannot alone activate a nAChR but can facilitate more efficient activation in combination with agonists at the canonical α4β2 sites. We therefore suggest categorizing agonists according to their site selectivity. NS9283 binds to the accessory ACh binding site; thus it is termed an accessory site-selective agonist. We expressed (α4β2)₂ concatamers in Xenopus oocytes with free accessory subunits to obtain defined nAChR stoichiometries and α4/accessory subunit interfaces. We show that α2, α3, α4, and α6 accessory subunits can form binding sites for ACh and NS9283 at interfaces with α4 subunits, but β2 and β4 accessory subunits cannot. To permit selective blockage of the accessory site, α4 threonine 126 located on the minus side of α4 that contributes to the accessory site, but not the α4β2 sites, was mutated to cysteine. Alkylation of this cysteine with a thioreactive reagent blocked activity of ACh and NS9283 at the accessory site. Accessory agonist binding sites are promising drug targets.     

戊型肝炎病毒实验感染恒河猴的研究

报道了用戊型肝炎（ＨｅｐａｔｉｔｉｓＥ,ＨＥ）病人粪便悬液感染恒河猴后的组织病理学、血液生化与免疫学以及病毒学分子生物学检测的结果。三只实验猴在感染后第３～４周均出现ＡＬＴ异常;粪便以及肝脏与胆囊组织超薄切片中电镜观察到２７～３４ｎｍ大小的病毒样颗粒;病理组织切片观察表明,肝脏组织有典型的急性炎症病灶;粪便与血清经ＲＴｎＰＣＲ扩增到戊型肝炎病毒（ＨｅｐａｔｉｔｉｓＥＶｉｒｕｓ,ＨＥＶ）特异性片段,粪便排毒从感染后第７天持续至第５０天左右,病毒血症迟于粪便排毒,出现于感染后两周左右,维持１～２周;ＥＬＩＳＡ检测发现,实验猴血清中ＨＥＶＩｇＧ抗体水平在感染后３～４周阳转,４～５个月后转阴。这些实验结果提示,恒河猴作为ＨＥＶ感染实验动物模型是理想的,建立系统的恒河猴实验模型对探讨ＨＥＶ感染发病机理、机体免疫应答以及临床诊断与疫苗研制具有重要意义。