1988 Fiscal Year Final Research Report Summary
Pathogenic factors of cell adherent Escherichia coli
| Project/Area Number |
62480156
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | Kagawa Medical School |
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Principal Investigator |
HAYASHI Hideo Professor, Kagawa Medical School, 医学部, 教授 (40033203)
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| Co-Investigator(Kenkyū-buntansha) |
KATAYAMA Sei-ichi Research Associate, 医学部, 助手 (70169473)
MINAMI Junzaburo Research associate, 医学部, 助手 (40157566)
OKABE Akinobu Associate Professor, 医学部, 助教授 (20093677)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Diarrheagenic E / coli / Cell adherence factor / Cytotoxin / K / oxytoca / gene cloning / C / perfringens / Perfringolysin |
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| Research Abstract |
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.
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