Molecular mechanism of infection and growth of endonuclear symbiotic bacterium.

(1).携带Holospora obtusa生殖短型的尾草履虫细胞在4偶联温度下的存活率高于非共生细胞。这是第一个证明钝齿刀齿和尾齿刀齿之间存在相互作用的证据。这一现象可能是携带全息孢子虫的草履虫只在寒冷地区发现的原因。Horospora的groEL同源物是一种热休克蛋白。制备了3种特异性的钝螺旋体感染长链单克隆抗体。免疫电镜观察发现其中两种与外周质发生反应。宿主消化液泡的酸化是细菌从液泡中逃逸和宿主细胞核感染所必需的早期事件。在康那霉素A或B的存在下，v - atp酶的抑制剂，液泡的酸化和细胞核的感染都被抑制。此外，当感染长型悬浮在pH3缓冲液中时，细菌表达了活化型特异性抗原，并表现出活化型特异性形态。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。纯化的H.obtusa 67 K蛋白单克隆抗体与可收缩的液泡-径向管道的质子泵和各种生物体的线粒体发生交叉反应。当生殖短型分化为感染性长型时，产生的过量细胞壁物质排泄到菌体外，在大核包膜周围积聚，引起包膜的低通透性。这可能是感染形式的草履虫裂变率低的原因。成功地将分离的直肠芽胞杆菌在85℃下低温保存127天，没有丧失其传染性和再生性。

(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.