1994 Fiscal Year Final Research Report Summary
PHYSIOLOGICAL ROLE OF HUMORAL DEFENSE FACTORS IN MARINE BIVALVE
| Project/Area Number |
04454091
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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 |
General fisheries
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
MORI Katsuyoshi FACULTY OF AGRICULTURE,TOHOKU UNIVERSITY PROFESSOR, 農学部, 教授 (50005617)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Keisuke FACULTY OF AGRICULTURE,ASSISTANT PROFESSOR, 農学部, 助手 (80240662)
OSADA Makoto FACULTY OF AGRICULTURE,ASSISTANT PROFESSOR, 農学部, 助手 (30177208)
MATSUTANI Takeshige FACULTY OF AGRICULTURE,ASSOCIATE PROFESSOR, 農学部, 助教授 (90134030)
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| Project Period (FY) |
1992 – 1994
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| Keywords | Oyster / Fibronectin / Lectin / Lysozyme / Myeloperoxidase / Bactericidal factor |
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| Research Abstract |
(1) Identification of humoral defense factors in the oyster
Several humoral factors which seem to involve in the host-defense of the pacific oyster, Crassostrea gigas, were biochemically identified. Purified oyster fibronectin in the hemolymph had a molecular mass of 420 kDa with a single subunit of 210 kDa. The existence of at least three kinds of lectin has been suggested in the hemolymph and two of them were purified. One is E-lectin which showed a specific binding with equine red blood cell and had a molecular mass of 630 kDa consisting of two subunits with molecular masses of 22 kDa and 23 kDa and the other is H-lectin with a molecular mass of 660 kDa consisting of two subunits of 21.5 and 22.5 kDa, which specifically bound with human red blood cell. Lysozyme molecule as a bactericidal factor having a molecular mass of 17 kDa was purified from the digestive diverticula. The occurence of myeloperoxidase which is generally believed to be related to kill bacteria in the phagocyte was
… More
first demonstrated in the hemocyte.
(2) Characteristics of humoral defense factors
Although oyster fibronectin had no cross-reactivity with human or rainbow trout fibronectin serologically, it appeared to have a common cellular recognition domain. Therefore, involvement of oyster fibronectin in the induction of cellular migration and adhesion at the site of wound healing was suggested. Both of fractions of E-lectin and H-lectin have strongly aggregated several kinds of bacteria and bound with a number of the other bacteria, suggesting non-self recognition of various species of microorganisms by these lectin. However, they showed no opsonic effect on phagocytosis. Purified lysozyme from the digestive diverticula was confirmed to be identical to the component which showed lysozyme activity in the digestive diverticula and mantle. On the other hand, other component with bactericidal activity was identified in the same tissue, which had different characteristics from lysozyme. Although the lysate of hemocyte had no lysozyme activity, the occurence of myeloperoxidase whith synthesizes poisonous hypochlorous acid was demonstrated in the hemocyte. It obviously showed a bacteria killing power, suggesting the presence of cellular microbicidal system. Less
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Research Products
(2 results)
