兔脊髓α受体对血量扩张引起肾交感神经活动抑制和促钠排泄的作用

在窦主动脉去神经麻醉兔观察阻断脊髓α受体对血量扩张引起肾交感神经活动（RSNA）抑制和促钠排泄反应的影响。兔脊髓蛛网膜下腔注射a肾上腺素能受体阻断剂酚妥拉明与人工脑脊液后,血量扩张引起RSNA抑制分别为（－25．4±5．4）％与（－42．5±5.2）％（P＜0.05）;兔脊髓蛛网膜下腔注射α1受体阻断剂哌唑嗪与人工脑脊液后血量扩张引起RSNA抑制分别为（－29．3±6.1）％与（－42．5±5.2）％（P＜005）。结果表明,阻断脊髓α受体或α1受体均可减弱血量扩张引起RSNA抑制。脊髓注射哌唑嗪后血量扩张引起促钠排泄与利尿反应也显著减弱（P＜005）。     

粪产碱菌nif H,nif D和部分nif K的克隆、定位及序列分析

提取粪产碱菌(Alcaligenes faecalis)总DNA,经限制性内切酶酶切和琼脂糖凝胶电泳,以含肺炎克氏杆菌(Klebsiella pneumoniae)nif H和nif H-D基因的DNA片段为探针进行Southern杂交,筛选出与nif HDK同源的4.6kb片段,克隆到pBluesript SK~+载体上,构建了重组质粒pBZl.经亚克隆、酶切、DNA序列分析后发现,粪产碱菌具有与其它固氮菌相似的结构特征,其nif HDK共用1个启动子,具有上游激活序列UAS,RNA聚合酶σ⁵⁴因子识别序列、1个A-T富集区和SD序列.nifH和nif D的阅读框架分别为888和1476bp,GC含量各为61.6%和60.2%.nifH-nif D和nif D-nif K的基因间隔区长度分别为101和105bp,各存在1个7bp的反向重复和1个SD序列.由阅读框架(ORF)推导的铁蛋白和钼铁蛋白α亚基的氨基酸序列与其它固氮菌相比有较高的同源性,高度保守的氨基酸残基所处的位置也很相似.同源性比较说明,粪产碱菌与棕色固氮菌(Azotobacter vinelandii)同源性最高.     

江浙蝮蛇毒碱性磷脂酶A2正交晶体分子置换法结构测定

江浙蝮蛇(Agkistrodon halys pallas)毒碱性磷脂酶A2具有很强的溶血作用.P2₁2₁2₁晶型的晶体学不对称单位中含有2个分子.用自身旋转函数研究了此2分子的相对空间关系,用交叉旋转函数和平移函数测定了2分子在晶胞中的取向与位置.在此基础上进行了初步的三维结构模型构建与结构修正.碱性磷脂酶A2正交晶体不对称单位中2个分子的排布呈现非晶体学二重对称关系.     

巨噬细胞免疫调变信号——Raf-1,MAPK,cPLA2的激活和IL-12分泌的研究

LPS介导的小鼠腹腔巨噬细胞免疫调变的信号和机理是不清楚的.应用LPS和PMA处理抑制性巨噬细胞后,发现Ras下游信号分子Raf-1,MAPK和cPLA₂均被活化,包括Raf-1的磷酸化,MAPK p44和p42磷酸化以及cPLA_2的活化,使花生四烯酸的释放显著增加,结合新近发现的LPS、PMA能诱导抑制性巨噬细胞PKC-α和PKC-ε同工酶的激活与转位,认为在LPS介导的免疫调变中,PKC信号通路的活化及其与Raf-1/MAPK通路的“连接”是主要信号传导通路.同时调变巨噬细胞也能分泌IL-12.     

巨噬细胞免疫调变信号:Raf-1,MAPK p44,MAPK p42和p38 MAPK的研究

为了了解巨噬细胞免疫调变机理,我们应用LPS和PMA处理小鼠抑制性巨噬细胞,观察到Ras下游信号分子Raf-1,分裂原激活蛋白激酶MAPK p44,MAPK p42和p38 MAPK均被活化,发现forskolin能增强p38 MAPK的活性,进一步提示PKC和PKA途径增强了p38 MAPK的磷酸化效应,为我们了解LPS如何激活p38 MAPK信号通路提供了一个新的机会。     

人肿瘤坏死因子α基因穿梭表达载体的构建和在鱼腥藻7120中的表达

报道了人肿瘤坏死因子α(hTNFα)基因穿梭表达载体的构建及其在丝状体蓝藻鱼腥藻 712 0中的表达和鉴定结果 .将质粒pRL rhTNF上hTNFα的cDNA连于pRL 43 9质粒上的PpsbA启动子下游 ,得到中间载体pRL TC .进一步与穿梭质粒pDC 8重组 ,得到可在大肠杆菌和蓝藻中均可表达的穿梭表达载体pDC TNF .pRL rhTNF ,pRL TC和pDC TNF三者在大肠杆菌中的表达量分别为 11.8% ,16 9%和 15 .0 % .通过三亲接合转移将pDC TNF引入鱼腥藻 712 0中并获稳定遗传的转基因株 .从转基因的鱼腥藻 712 0中检测到pDC TNF质粒的存在 ,且在和TNFα的cDNA探针进行的Southern杂交中呈阳性反应 .抽提转基因藻的蛋白样品进行检测 ,在Western印迹中和TNFα单克隆抗体呈阳性反应 .采用TNF对L92 9细胞的细胞毒性方法 ,证明转基因藻粗提液中 ,TNF确有细胞毒活性 .     

Expression of cytochrome P4502E1 in human liver: Relationship between genotype and phenotype in Chinese

Polymorphic cytochrome P4502E1 (CYP2E1) plays an important role in the metabolic activation of many carcinogens. We have previously shown that the c1/c1 genotype recognized byRsa I in the 5′-regulatory region of theCYP2E1 may be a susceptibility factor for developing esophageal cancer and lung cancer in Chinese. The present study was to investigate the relationship between theRsa I genotype and the expression of CYP2E1 in human livers. A total of 50 liver specimens were genotyped forCYP2E1 and assayed for CYP2E1 protein contents and functional activity by using specific antibody in immunoblot and a probe substrate,p-nitrophenol. A considerable interindividual variation in CYP2E1 protein (20-fold) and functional activity (56-fold) was observed among these liver samples. However, when they were categorized according to genotype, the mean content of CYP2E1 protein was significantly higher among individuals with the c1/c1 genotype than that among those having c1/c2 or c2/c2 genotype [124.0±83.9 pmol/mg (n = 28) versus 65.5 ±38.9 pmol/mg (n = 22),P<0.01]. The mean activity of CYP2E1 towardsp-nitrophenol for the c1/c1 genotype was also higher than that for the variant genotypes (198.4±27.8 pmol/min/mg versus 101.2 ±18.1 pmol^-1 · min^-1 · mg^-1,P<0.01). Also, the protein levels and functional activity showed a significant correlation (r = 0.68,P<0.01). These results demonstrate an association between theRsa I genotype and the phenotype of CYP2E1 in our samples, and the data are compatible with the assumption thatCYP2E1 c1/c1 genotype is a susceptibility factor for certain cancers in Chinese.     

新疆维吾尔族妇女宫颈癌组织中乳头瘤病毒16型E6基因的克隆和序列分析

为了分析新疆南部地区维吾尔族妇女宫颈癌组织中HPV16型E6基因结构特点，从中国新疆南部地区维吾尔族妇女宫颈癌活检组织标本中提取DNA，以宫颈癌活检组织标本DNA为模板进行PCR扩增，获得HPV16 E6基因，将其克隆到pUCm-T载体上，并对其进行基因全序列分析.PCR检测结果显示宫颈癌组织中HPV16 E6阳性率为82.35%（14/17）；测序结果显示，新疆株HPV16 E6基因全长456 bp，大小与德国标准株一致.E6基因的第247位碱基发生T→G突变，并由此引起所编码的氨基酸亦发生改变.上述结果表明，中国新疆南部地区维吾尔族妇女宫颈癌患者组织中HPV16 E6的基因结构与德国标准株HPV16 E6基因之间存在差异.     

Survival and DNA Repair of Somatic Cell Hybrids after Ultraviolet Irradiation

THE technique of somatic cell hybridization has opened up studies on genetic regulation¹ and human genetic analysis^2–5. Hybrid cells are isolated in conditions that select against parental cells while allowing hybrids to survive by genomic complementation. In xeroderma pigmentosum (XP), a human disease with an autosomal recessive defect in an early stage of DNA repair⁶, the skin is extremely sensitive to sunlight in vivo⁷ and skin fibroblasts show sharply reduced survival following ultraviolet irradiation in vitro^8,9. This communication concerns the use of ultraviolet irradiation in combination with a chemical method to produce hybrids between fibroblasts from XP and a hamster line, followed by analysis of these cells for their capacity to survive and repair DNA after exposure to ultraviolet. Methods for initiation and propagation of skin fibroblasts from two subjects, male and female siblings with XP, have been described⁸. Details on the origin of the TG2 line of golden hamster fibroblasts, which has a non-reverting mutation in the gene for hypoxanthine-guanine phosphoribosyltransferase (HGPRT), the general hybridization procedure¹⁰ and methods for cell survival and DNA repair by unscheduled synthesis⁸ were also described previously. Hybrids were produced by fusion with Sendai virus and selected by ultraviolet irradiation followed by culture on HAT medium (Fig. 1).