| Project/Area Number |
60860020
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
General fisheries
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| Research Institution | Faculty of Agriculture, Kochi Univercity |
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Principal Investigator |
KUSUDA Riichi Faculty of Agriculture, Kochi Univercity, Professor, 農学部, 教授 (90036715)
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| Co-Investigator(Kenkyū-buntansha) |
松原 明政 アース製薬株式会社, 技術部, 研究員
橋本 伸一 アース製薬株式会社, 技術部, 研究員
MIHARA Shigeru Technical reserch development, Earth chemical company Ltd., Chief investigator, 技術部, 主任研究員
NISHIMURA Akira Technical reserch development, Earth chemical company Ltd., The head of technica, 技術部, 技術部長
KAWAI Kenji Faculty of Agriculture, Kochi Univercity, Assistant Professor, 農学部, 助教授 (60127925)
HASHIMOTO Shinichi Technical reserch development, Earth chemical company Ltd., Investigator
MATSUBARA Akimasa Technical reserch development, Earth chemical company Ltd., Investigator
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1986: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1985: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | Pseudotuberculosis in yellowtail / Immersion vaccine / Immunity / Vaccine / Immunization of fish / Preservation of bacterial strain / Preservation of Pasteurella piscicida / 海産魚のワクチン / ブリ / 感染防御因子 / ハマチの類結節症 |
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| Research Abstract |
To develop a Pastuerella piscicida vaccine for yellowtail, the following subjects have been studied: optimal conditions to produce bacterial cells, mechanisms of infection and immune response in yellowtail and effecacy of vaccination methods.
Pathogenicity of a selected highly virulent strain could be preserved best by lyophilization in Mist. desiccans. Optimal range of culture conditions to obtain high yield of P. piscicida were 22.5 - 30゜C, pH 6.47 - 7.24 and 1.0 - 2.0 % of sodium chloride with shaking for 24 hours.
The site of invasion of the pathogen was investigated by immersing fish in a bacterial suspension, covering different areas of the body surface with plastic film. The infection on both the head and the trunk resulted in high mortality. However, incorporation of <^(14)C> was highest in the gill after immersing fish in a suspension of <^(14)C> -labelled live bacteria. This result indicates that the pathogen invades the organism mainly through the gill. Survival rate of a highly virulent strain in fish serum was higher than that of a weakly virulent strain which suggests that serum resistance is one of the virulence factors of the bacteria. Antibody titers of the sera of the fish immunized by immersion, which could not be measured with accuracy using agglutination reaction, was determined by ELISA. Antibody in the skin mucus showed similar antigenicity to that in the serum.
A single immersion vaccination with formalin-killed bacterin did not result in a satisfactory protection as detected in the challenge test. Multiple immersion or a combination of immersion and oral vaccination evoked a higher protection rate. Immersion immunization with extracted lipopolysaccharide and disrupted cells of P. piscicida, respectively resulted in higher protection rate than that observed after using formalin-killed whole cells as an immunogen.
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