2000 Fiscal Year Final Research Report Summary
"Study on symbiotic relationship between gut microbes and marine herbivores"
| Project/Area Number |
09460081
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General fisheries
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
EZURA Yoshio Hokkaido Univ., Grad.School of Fis., Prof., 水産科学研究科, 教授 (80001618)
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| Co-Investigator(Kenkyū-buntansha) |
SAWABE Tomoo Hokkaido Univ., Grad.School of Fis., Inst., 水産科学研究科, 助手 (30241376)
YOSHIMIZU Mamoru Hokkaido Univ., Grad.School of Fis., Prof., 水産科学研究科, 教授 (40122915)
TAJIMA Kenichi Hokkaido Univ., Grad.School of Fis., Asso.Prof., 水産科学研究科, 助教授 (80002252)
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| Project Period (FY) |
1997 – 2000
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| Keywords | abalone / gut microbes / Vibrio halioticoli / symbiosis / distribution / species-specific detection system / host-specific polymorphism / alginate fermentation |
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| Research Abstract |
Aim of the project has been orientated to clarify physiological and ecological functions of gut microbes living in gut of marine herbivores. The project has directed to obtain many excellent results for understanding an abalone-gut microbes interaction as follows ;
1. Changes of the gut microflora of abalone were corresponding to a time when a feeding behavior of abalone was changed.
2. One of the dominant microbes in the gut of abalone was Vibrio halioticoli, which was identified as a new species of Vibrio.
3. Three kinds of V.halioticoli specific identification methods were developed based on 1) 16S rDNA PCR/RFLP, 2) colony hybridization, and 3) in situ PCR.
4. Use of the V.halioticoli-specific identification method clarified the interesting distribution.
1) V.halioticoli was distributed in seawater in/around an abalone farm, and likely to attach on a surface of microalgae. The bacterium may be reached with the microalgae into the gut of abalone. A change of gut environments creating by a change of the feeding behavior caused the bacterium dominancy in the gut.
2) V.halioticoli was also distributed in abalones, H.discus discus, H.diversicolor supertexta, and H.diversicolor diversicolor ; and a turban shell, Turbo cornatus, living in Japan. The bacterium was not isolated from Australian, South African and French abalones.
5. Fingerprinting analysis suggested an occurrence of host specific polymorphism among V.halioticoli strains isolated from various abalones.
6. Four genes encoding alginate degrading enzymes of V.halioticoli IAM14596^T were cloned and sequenced.
7. Preliminary experiment for an artificial substitution of gut microflora of abalone Haliotis discuss hannai using antibiotics-containing diet resulted that an occupation rate of V.halioticoli in the gut of the abalone was decreased below 0.1%.
8. Main fermentation products from alginate by V.halioticoli IAM 1459^T were determined as acetic acid and formic acid.
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