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Pathogenic factors of cell adherent Escherichia coli

细胞贴壁大肠杆菌的致病因素

基本信息

批准号：
62480156
负责人：
HAYASHI Hideo
金额：
$ 4.29万
依托单位：
Kagawa Medical School
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

The adherence properties and cytotoxicity of enteropathogenic Escherichia coli have been studied with isolated strains from bacterial diarrhea diseases. Some of the strains adhered to tissue cultre cells of humans origin when checked by a new method of the assay that we invented. The surface properties of those bacterial cells were examined by electronmicroscopy as well as biological activities. The ultrastructure of fragella was varied in each H type and the correlation between the structure and the types were re-examined and reviewed. A new aspect on the mode of self assembly of fragellines was proposed. The ultrastructure of fimbriae of those strains were not distinguishable with previous reports but some of them lacked for both MS and MR hemoagglutination. The fimbriae seemed to be coded for 60Kb plasmid and the molecular cloning is being undertaken. The strains had weak cytotoxic activities on Vero, HEp-2 and HeLa cells, but the activity was easy to be modified by uncertain factors. The similar activity was detected in K. oxytoca isolated from hemorrhagic colitis and we analyzed the properties of the toxin. The toxin seemed to be coded for 30Kb plasmid and the characterization of the gene is on the way. By establishing techniques and facilities for genetic analysis of pathogenic factors of bacteria, we succeeded in molecular cloning of -toxin ( perfringolysin ) and -toxin ( phospholipase C ) of clostridium perfringens of which gene cloning have been unsuccessful because of the hazards of clostridial strong D Nase activities. We established the gene library and the other pathoqenic extracellular enzymes of clostridium are extensively examined.The regulation of gene expression of heat labile enterotoxin was studied with the isolated etec strains which were varied in the productivity of the enterotoxin. It was suspected that the amount of the toxin production should be regulated at the level of transcription.

用细菌性腹泻病分离株研究了肠致病性大肠杆菌的粘附特性和细胞毒性。用我们发明的一种新的检测方法检测时，有些菌株粘附在人源组织培养细胞上。用电镜观察了菌体的表面性质，并测定了菌体的生物活性。各H型的脆裂体超微结构各不相同，并对各类型间的关系进行了重新研究和综述。对碎片链的自组装模式提出了新的见解。菌毛的超微结构与以往报道无明显区别，但部分菌株同时缺乏MS和MR血凝反应。菌毛可能编码60 Kb质粒，分子克隆正在进行中。该菌株对Vero、HEp-2和HeLa细胞具有较弱的细胞毒活性，但其活性易受不确定因素的影响而改变。在K.从出血性结肠炎中分离出催产素，我们分析了毒素的性质。该毒素可能由30 Kb质粒编码，基因的鉴定正在进行中。通过建立细菌致病因子遗传分析技术和设施，成功地克隆了因梭菌强DNA酶活性的危害而未能成功克隆的产气荚膜梭菌-毒素（产气荚膜梭菌溶素）和-毒素（磷脂酶C）的分子。我们建立了梭菌基因文库，并对梭菌的其他致病性胞外酶进行了广泛的研究，利用产肠毒素能力不同的菌株研究了不耐热肠毒素基因的表达调控。推测毒素的产生量应在转录水平上进行调控。