单核细胞增多性李斯特菌的脉冲场凝胶电泳分型研究

用限制性内切酶Sma Ⅰ和Apa Ⅰ分别对21株单核细胞增多性李斯特菌菌株基因组DNA进行酶切,用脉冲场凝胶电泳（PFGE）方法进行遗传多样性分析。结果表明：3株临床分离株（00181、00174和0194）分别存在于亚型A、B、D中;16个单核细胞增多性李斯特菌奶相关和环境分离株主要存在于4个亚型中,其中2个亚型（C、D）均为奶相关分离株（包括原料奶、均质奶（储奶罐）和成品奶分离株）,而加工厂地面污水分离株为独立的一个亚型（A）。     

重组人生长激素在毕赤酵母中的表达研究

通过单因素分析和正交实验法优化高密度发酵培养基和诱导条件,根据优化结果指导发酵罐发酵.得到改良BSM培养基的最佳配比为甘油30g/L、酵母粉14g/L、K2SO4 13g/L、MgSO4·7H2O 11g/L、CaSO4 0.3g/L、PTM1 4.4mL、0.1mol/L磷酸盐缓冲液(pH＝6.5);得到摇瓶培养最佳诱导条件为种龄24h,诱导时间30h,甲醇浓度2%,pH6.3～6.9.瑞士Bioengineering公司L1523型发酵罐发酵结果显示,细胞光密度(OD600)达到294,rHGH表达量最高达到0.54g/L.     

凝胶过滤法分离纯化大豆蛋白肽

本文采用中性蛋白酶AS1.398水解大豆蛋白,通过正交实验确定最佳水解条件:水解温度、pH值分别为48℃和7.5,底物浓度为5%(W/V),酶用量为6%,酶解时间为4h,此时水解度(DH)达到24.57%。并对水解产物进行脱苦脱色,然后采用超滤以及凝胶过滤色谱法分离分子量1200以下的小肽并收集。     

Mapping of the class II region of the human major histocompatibility complex by pulsed-field gel electrophoresis

The class II region of the human major histocompatibility complex (MHC) encodes a polymorphic set of cell surface glycoproteins involved in the regulation of the immune response. Each glycoprotein is a heterodimer composed of a alpha-chain of relative molecular mass (Mr) 34,000 (34 K) and a beta-chain of Mr = 28K. The products of the class II region have been characterized by the mixed lymphocyte reaction, serology, primed lymphocyte typing and DNA cloning. DR, DQ and DP, three subregions containing both alpha- and beta-chains, and two additional loci, DZ alpha and DO beta, locate this gene cluster on the short arm of chromosome 6. The precise genomic organization of these loci have been difficult to determine. Here we describe the use of pulsed-field gel electrophoresis together with restriction endonucleases having few genomic restriction sites and Southern blotting, to determine the order of the subregions and to derive a map for the human class II region. The order of these loci is similar to that of the homologous loci in the murine class II region. Our study establishes the use of pulsed-field gel electrophoresis in mapping large regions of the genome in higher eukaryotes.     

人骨骼肌双向电泳条件优化及部分蛋白质鉴定

目的建立和优化人骨骼肌组织双向电泳模型,为深入探讨骨骼肌萎缩的分子机制提供方法上的保障。方法使用两性离子去垢剂CHAPS和SB3-10,并配合不同浓度的离液剂抽提骨骼肌蛋白质,并通过双向电泳对蛋白质进行分离,用基质辅助激光解析电离飞行时间质谱(MALDI-TOF)对选取的蛋白质进行鉴定。结果优化过的双向电泳模型可在一张凝胶上分离800多个蛋白质点,通过MALDI-TOF鉴定出HUMANserine/threonine protein kinase KKIALRE等4种低丰度蛋白质。结论多种去垢剂和离液剂的组合使用才能获得对组织中蛋白质较好的抽提效果。获得的人骨骼肌双向电泳图谱是对人类骨骼肌蛋白质组学数据库的有益补充,为使用比较蛋白质组学方法筛选人肌病关键蛋白质提供了实践和理论基础。     

Re-routing of a secretory protein by fusion with human growth hormone sequences

Cells with electron-dense secretory vesicles use them to store only specialized secretory products such as peptide hormones; other types of secreted proteins are externalized by an alternative, constitutive route. One possible mechanism for such segregation is that proteins destined for dense secretory vesicles contain unique 'sorting domains' that allow for selective targeting. Here, we set out to determine whether a constitutively secreted protein could be diverted to the dense secretory vesicles by attachment to a peptide hormone sequence. We made use of the ability of the mouse pituitary tumour cell, AtT-20, to correctly sort exogenous secretory proteins introduced into them by DNA transfection. We constructed a plasmid encoding a hybrid protein in which a constitutively secreted viral protein was fused to the carboxy terminus of human growth hormone (hGH). Cells expressing the hybrid protein were found to target it to dense secretory vesicles with an efficiency close to that observed for the parental hGH. These results support the hypothesis that sorting domains on peptide hormones direct their packaging into dense secretory vesicles. The results also suggest that proteins secreted by the constitutive pathway either do not contain any sorting domain, or their sorting signals can be overridden by those which direct peptide hormones.     

Abnormal pattern detected in fragile-X patients by pulsed-field gel electrophoresis.

The fragile-X syndrome is the most frequent inherited form of mental retardation, with an incidence of 1 in 1,500 males. It is characterized by the presence of a fragile site at Xq27.3 induced in vitro by folate deprivation or by inhibitors of deoxynucleotide synthesis. Its mode of inheritance is unusual for an X-linked trait, with incomplete penetrance in both males and females. Some phenotypically normal males transmit the mutation to all their daughters who rarely express any symptoms, but penetrance is high in sons and daughters of these carrier women. Genetic and physical mapping of the Xq27-q28 region has confirmed that the disease locus is located at or very near the fragile site. Hypotheses proposed to account for the abnormalities in the inheritance of the disease include sequence rearrangements by meiotic recombination or a mutation that affects reactivation of an inactive X chromosome during differentiation of female germ cells. To detect such rearrangements, or methylation changes that may reflect a locally inactive X chromosome, we used pulsed-field gel analysis of DNA from fragile-X patients with probes close to the fragile-X locus. The probe Do33 (DXS465) detected abnormal patterns in fragile-X patients, but not in normal controls or in non-expressing male transmitters.     

木霉菌的形态学和可溶性蛋白质电泳鉴定与分类

对61株来自不同植物根际的木霉菌（Trichoderma spp.)进行了形态学鉴定，其中哈茨木霉菌（Trichoderma harzianum)有47株，绿色木霉菌（Tricoderma viride)10株，康宁木菌（Trichoderma koningii)和绿色木霉菌（Trichoderma virens)分别为两株，对这些菌株进行了可溶性蛋白质电泳分析，并采用UPGMA选取和类分析，结果表明，将距离系数D＝13.8作为聚类分析阈值，61个菌株可分为A，B，C三个组，距离系数D＝9．1时，A组可分为A1，A2，A3，A4，A5五个亚组，A组包括47株哈茨木霉菌，是主要成员。此外A组还有8株绿色木霉菌，两株绿木霉菌和一株康宁木霉菌，B组只有一株绿色木霉菌，C组由一株绿色木霉菌和一株康宁木霉组成，表明木霉菌具有明显的形态学多样性，而哈茨木霉是存在种下分类群，还发现蛋白质电泳分类结果与菌株的地缘有关。