1995 Fiscal Year Final Research Report Summary
Molecular mechanism of infection and growth of endonuclear symbiotic bacterium.
| Project/Area Number |
05454028
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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 |
動物生理・代謝
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| Research Institution | YAMAGUCHI UNIVERSITY |
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Principal Investigator |
FUJISHIMA Masahiro Yamaguchi University, Faculty of Science, Professor, 理学部, 教授 (40127783)
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| Project Period (FY) |
1993 – 1995
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| Keywords | Endonuclear symbiotic bacterium / Holospora / Proton pomp / Digestive vacuole / Cell wall / Concanamycin / Paramecium / Macronucleus |
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| Research Abstract |
(1).Paramecium caudatum cells bearing the reproductive short forms of Holospora obtusa show high servival ratio compared with aposymbiotic cells at 4ﾟC.This is the first evidence showing a presence of mutual interaction between H.obtusa and P.caudatum. This phonomenon may be a cause why the Holospora-bearing paramecia is found only in cold area.
(2).Horospora's groEL homologue is a heat-shock protein.
(3).Three monoclonal antibodies specific for infectious long from of H.obtusa were developed. Two of them was found to react with periplasm by immunoelectron microscopy.
(4).Acidification of the host digestive vacuole is an early event required for the bacterial escape from the vacuole and for infection of the host nucleus. In the presence of concanamycin A or B,inhibitors of V-ATPase, both acidification of the vacuoles and infection of the nucleus were inhibited. In addition, when the infectious long forms were suspended in pH3 buffer, the bacteria expressed the activated form specifc antigen and showed activated forms specific morphology. Thus, it seems that acidification in the host digestive vacuole is a trigger for the escape of the bacteris from the vacuole and for differentiation of the activated form.
(5).Monoclonal antibody raised for purified 67 K protein of H.obtusa cross-reacted with a proton pump of the contractile vacuole-radial canals and mitochondoria of various organisms.
(6).When the reproductive short form differentiated into the infectious lonf form, cell-wall materials produced excess amount were excreted outside the bacteria and accumulated around the macronuclear envelope and induced low permeability of the envelope. This may be a cause of low fission ratio of the infectious form-bearing paramecia.
(7).Cryopreservation of the isolated H.recta was succeeded without loss of the infectivity and reproducebility at-85ﾟC at least 127 days.
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