| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2004: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
We observed that Campylobacter jejuni strain 81-176, a strong slime producer, showed spreading and highly mucoid colonies on blood agar plates, and formed biofilm on the bottom of a glass flask after stationary cultivation in Brucella broth. The present study was performed to determine the genes associated with biofilm formation, eight mutants were constructed from strain 81-176 by natural transformation-madiated allelic exchange. As aflagellate (flaA^-B^- and flbA^-) and flagellate but nonmotile (pflA^- and motA^-) mutants did not form a biofilm exhibited by the wild type strain even though capsular-like polysaccharide was expressed on the cell surface. In contrast, kpsM and peb1 mutants which lack capsular-like polysaccharide and an outer membrane protein, respectively, retained the ability of biofilm formation. Furthermore, luxS and cheY mutants which were associated with cell to cell signaling and chemotaxis, respectively, did not affect the ability of biofilm formation. These findings suggest that flagella-mediated motility is required for biofilm formation in vitro.
Survival of C.jejuni in the environment under non-growth conditions was examined using a biofilm-forming strain and its lacked mutant (motA^-) or planktonic cells. The organisms were spiked on pulp disks or treated with heat, sanitizers, or antibiotics. Survival was determined by the number of culturable cells on non-selective blood agar plates. In all the experiments, biofilm forming cells of C.jejuni can survive longer than biofilm non-forming mutant or planktonik cells, suggesting that biofilm formation is important to survive under environment conditions without hosts.
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