内毒素所致SIRS/MODS小鼠脾细胞损伤的形态学观察

目的 应用大肠杆菌内毒素脂多糖（LPS）腹腔注射制备小鼠全身炎症反应综合片/多器官功能失常综合征（SIRS/MODS）模型。方法 用免疫组化的方法检测了Bcl-2的表达。结果 随LPS作用时间的延长,脾损伤逐渐加重,HE染色中,生发中心和动脉周围淋巴鞘分别在LPS注射后9小时和18小时出现大量深浅不一的颗粒状细胞碎片。TUNEL阳性染色细胞随时间延长而增多,电镜下可见到凋亡的淋巴细胞,在18小时还见到细胞坏死现象,Bcl-2的表达随着LPS作用时间的延长而明显下降,与TUNEL染色的相关分析表明,Bcl-2的表达与细胞凋亡有显著的负相关。结论 在LPS所致的SIRS/MODS模型中,脾细胞损伤以凋亡为主,随LPS作用时间延长而加重,在晚期还会出现细胞坏死。Bcl-2参与了LPS引起的脾细胞凋亡效应。     

人端粒结合蛋白TRF1的克隆、表达和抗体制备

利用RT-PCR技术,从HeLa细胞的cDNA文库中扩增到人端粒结合蛋白1(hTRF1)基因编码区序列,克隆至pUCm-T载体,测序正确后,构建带His₆-tag原核表达载体pET-28c-TRF1,经IPTG诱导表达的His₆-TRF1融合蛋白分子量约为65kD,Western-blot证实表达产物可特异地与TRF1抗体sc-6165结合。用Ni^2＋NTA胶亲和层析纯化可得到电泳均一的融合蛋白,免疫新西兰纯种大白兔,获得特异性好的多克隆抗体,该抗体可用于免疫荧光染色和Western-blot方法检测哺乳动物细胞内源性的TRF1分子。     

海洋生物毒素的药物开发前景

本对海洋生物毒素的研究现状及其在神经系统、心血管系统等方面的作用做了简要的综述,并对海洋生物毒素在药物开发中的应用前景及展望予以探讨。     

小分子药靶——RNA药靶研究进展

对RNA药靶的特点、研究策略和针对RNA药靶的小分子药物筛选方法,进行了综述.RNA的三级结构作为分子相互作用的识别位点和结合位点对RNA的生物功能的实现具有重要决定作用,RNA分子同蛋白质一样将成为新型小分子药物的作用靶点.     

盐碱池塘围隔生态系统浮游原生动物种群增长和生产量

1998年 5～ 9月用原位测定法研究了盐碱池塘无鱼和单养鲢围隔生态系统浮游原生动物的种群增长和生产量。结果表明 ,原生动物主要优势种团焰毛虫、瓜形膜袋虫、旋回侠盗虫、绿色前管虫和拟急游虫的世代时间分别为 6 93～ 2 3 10、 6 30～ 18 73、 9 90、 9 90～ 14 75和 7 6 2hr,其种群增长率分别为 0 0 30～ 0 10 0、0 0 37～ 0 110、 0 0 70、 0 0 47～ 0 0 70和 0 0 91/hr。 5～ 8月份无鱼和有鱼围隔原位试验瓶中原生动物累积日均产量分别为 10 70 2 5和 944 2 5mg/m3 ·d ,而相同时间两围隔中原生动物按月计算的日均生产量分别为 1 79和9 72mg/m3 ·d ,日P/B系数分别为 2 5 0和 2 0 3。无鱼围隔原生动物生物量和生产量均比有鱼围隔的低。     

桂花品种资源的遗传多样性分析

根据桂花(Osmanthus fragrans)品种的形态特征, 结合AFLP分子标记, 对部分桂花栽培品种进行了遗传多样性分析。结果表明, 桂花品种之间存在着较为丰富的遗传多样性, AFLP分子标记检测到的多态性条带占总扩增条带的57.46%。 根据桂花品种的主要性状特征, 利用数值分类法对其进行分类, 并用UPGMA法对AFLP结果进行聚类分析, 结果均显示桂林地区的桂花品种存在明显的区域性, 花色可以作为重要的分类标准, 同时对桂花品种的分类系统进行了探讨。     

水稻穗长基因PAL3的克隆及自然变异分析

穗型是决定水稻(Oryza sativa)产量的关键因素之一。我们从粳稻品种圣稻808 (SD808)的EMS诱变突变体库中发现4份短穗突变体,这些突变体的穗长、一级枝梗数、二级枝梗数和穗粒数发生不同程度的降低。基因定位和图位克隆表明,这些突变体的表型受同一基因控制,将该基因命名为PAL3 (PANICLE LENGT...     

Toward tailoring the specificity of the S1 pocket of subtilisin B. lentus: chemical modification of mutant enzymes as a strategy for removing specificity limitations.

In both protein chemistry studies and organic synthesis applications, it is desirable to have available a toolbox of inexpensive proteases with high selectivity and diverse substrate preferences. Toward this goal, we have generated a series of chemically modified mutant enzymes (CMMs) of subtilisin B. lentus (SBL) possessing expanded S(1) pocket specificity. Wild-type SBL shows a marked preference for substrates with large hydrophobic P(1) residues, such as the large Phe P(1) residue of the standard suc-AAPF-pNA substrate. To confer more universal P(1) specificity on S(1), a strategy of chemical modification in combination with site-directed mutagenesis was applied. For example, WT-SBL does not readily accept small uncharged P(1) residues such as the -CH(3) side chain of alanine. Accordingly, with a view to creating a S(1) pocket that would be of reduced volume providing a better fit for small P(1) side chains, a large cyclohexyl group was introduced by the CMM approach at position S166C with the aim of partially filling up the S(1) pocket. The S166C-S-CH(2)-c-C(6)H(11) CMM thus created showed a 2-fold improvement in k(cat)/K(M) with the suc-AAPA-pNA substrate and a 51-fold improvement in suc-AAPA-pNA/suc-AAPF-pNA selectivity relative to WT-SBL. Furthermore, WT-SBL does not readily accept positively or negatively charged P(1) residues. Therefore, to improve SBL's specificity toward positively and negatively charged P(1) residues, we applied the CMM methodology to introduce complementary negatively and positively charged groups, respectively, at position S166C in S(1). A series of mono-, di-, and trinegatively charged CMMs were generated and all showed improved k(cat)/K(M)s with the positively charged P(1) residue containing substrate, suc-AAPR-pNA. Furthermore, virtually arithmetic improvements in k(cat)/K(M) were exhibited with increasing number of negative charges on the S166C-R side chain. These increases culminated in a 9-fold improvement in k(cat)/K(M) for the suc-AAPR-pNA substrate and a 61-fold improvement in suc-AAPR-pNA/suc-AAPF-pNA selectivity compared to WT-SBL for the trinegatively charged S166C-S-CH(2)CH(2)C(COO(-))(3) CMM. Conversely, the positively charged S166C-S-CH(2)CH(2)NH(3)(+) CMM generated showed a 19-fold improvement in k(cat)/K(M) for the suc-AAPE-pNA substrate and a 54-fold improvement in suc-AAPE-pNA/suc-AAPF-pNA selectivity relative to WT-SBL.