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Molecular mechanism of infection and growth of endonuclear symbiotic bacterium.

核内共生菌感染和生长的分子机制。

基本信息

批准号：
05454028
负责人：
FUJISHIMA Masahiro
金额：
$ 3.97万
依托单位：
YAMAGUCHI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

项目摘要

(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.

(1).具有生殖短型Holospora obtusa的生殖短型的尾草履虫细胞在4℃下与非共生细胞相比表现出较高的成活率。这是显示H.obtusa和P.caudatum之间存在相互作用的第一个证据。这种现象可能是导致Holospora草履虫只出现在寒冷地区的原因。(2).Horospora的groEL同源物是一种热休克蛋白。(3).开发了三种针对H.obtusa感染性长虫的特异性单克隆抗体。免疫电镜发现其中两种与周质发生反应。(4)宿主消化液泡的酸化是细菌逃离液泡和感染宿主细胞核所需的早期事件。在存在 V-ATP 酶抑制剂刀那霉素 A 或 B 的情况下，液泡的酸化和细胞核的感染均受到抑制。此外，当感染性长形式悬浮在pH3缓冲液中时，细菌表达活化形式特异性抗原并表现出活化形式特异性形态。因此，宿主消化液泡中的酸化似乎是细菌从液泡中逃逸并分化为活化形式的触发因素。(5).针对 H.obtusa 的纯化 67 K 蛋白产生的单克隆抗体与各种生物体的收缩液泡-径向管和线粒体的质子泵发生交叉反应。(6).当繁殖时短型分化为感染性长型，产生的过量细胞壁物质被排泄到细菌体外并积聚在大核包膜周围，导致包膜通透性降低。这可能是感染性草履虫裂变率低的原因。(7).分离的直肠草在-85℃下成功冷冻保存至少127天，且不丧失感染性和繁殖性。