The group studies on the structural and functional roles of the bacterial surfaces in the infections.

本项目成员的工作可分为三个不同的实验组，定植因子组，细胞表面材料的生物活性组和入侵机制组。现将三年来各小组的实验结果总结如下：定植因子的分类：从几种细菌中分离、纯化了定植因子，并对其化学成分进行了分析。在大肠杆菌中分离到一种新的被称为CFA III的菌毛并对其进行了鉴定。在粘质葡萄球菌中克隆了一个MR菌膜基因，并在大肠杆菌中表达。其DNA序列分析表明，该菌毛亚基n端氨基酸序列与其他形态上难以区分的大肠杆菌毛的氨基酸序列几乎相同。血凝作为霍乱弧菌的定殖因子，对其在人肠粘膜上的粘附作用进行了研究。表面材料的生物活性：作为细胞壁成分的生物效应之一，膜基二肽MDP对内毒素的毒性作用表现出刺激作用。经MDP预处理的小鼠在静脉注射少量LPS后出现过敏反应。这一现象的机制还有待阐明。利用凝固酶和蛋白A细胞壁成分的缺陷突变体，研究了凝固酶和蛋白A在金黄色葡萄球菌感染中的作用。凝固酶与这种细菌的毒力关系更密切。侵袭性组：为分析志贺氏杆菌的侵袭性，制备了针对sonnei志贺氏杆菌细胞表面的单克隆抗体。一些克隆只与该细菌的I期菌株反应。这些抗体可能有助于分析该细菌的侵袭因素。在梭状芽胞杆菌（Clostridium spp.）上进行了细胞表面保护屏障规则表面阵列的形态学和生物学研究。少

The works of the member in this project can be categorized into three different experimental groups, the group on the colonization factor, on the biological activity of cell surface materiales and on the invasing mechanisms. The experimental results of these groups in these three years are summerized as follow.The group of the colonization factors: From several species of bacteria fimbrial colonization factors were isolated, purified and the chemical compositions were analysed. In E. coli a new fimbriae called CFA III was isolated and ch aracterized. In S.marcescens a gene for MR fimbria was cloned and expressed in E. coli. Its DNA sequence analysis showed that the sequence of amino acids at the N-terminal portion of the fimbrial subunit was almost the same as those of the other morphologically indistinguishable fimbria of E. coli. As a colonization factor for Vibrio cholerae the roles of hemagglution on the adherece on the intestinal mucosa of human was demonstrated.The group of biolo … More gical activity of suface materiales: As one of the biological effects of the cell wall components, MDP,a muramyl dipeptide, exserted a stimulating effect against the toxic effect of the endotoxin. Mice pretreated with MDP showed an anaphylactic reaction when a small amount of LPS was administered intravacularly. The mechanisms of this phenomenon is remained to be elucidated. The role of coagulase and protein A on the infection of Staphylococcus aureus are investigate using the deficient mutant of these cell wall components. Coagulase is more closely related to the virulence of this bacteria.The group of the invasiveness: For the analysis of the invasivenes of Shigella spp. the monoclonal antibodies for the cell surface of Sh. sonnei was produced. Some of the clones were reacted only with phase I strains of this bacteria. These antibodies might be usefull for the anlysis of invasive factors of this bacteria. The morphological and biological studies of the regular surface array ,an protective barrier on the cell surface, were carried out on Clostridium spp.. Less