Quantitative Changes in Periplasmic Proteins of the Macronucleus‐Specific Bacterium Holospora obtusa in the Infection Process of the Ciliate Paramecium caudatum
Quantitative Changes in Periplasmic Proteins of the Macronucleus‐Specific Bacterium Holospora obtusa in the Infection Process of the Ciliate Paramecium caudatum
复制标题
尾部纤毛虫感染过程中大核特异性细菌 Holospora obtusa 周质蛋白的定量变化
DOI：
10.1111/j.1550-7408.1997.tb05971.x
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发表时间：
1997
影响因子：
2.2
通讯作者：
M. Kawai
中科院分区：
文献类型：
--
作者：
M. Fujishima;H. Dohra;M. Kawai
摘要。革兰氏阴性细菌Holospora obrusa是纤毛虫草履虫的大核特异性共生体。这种细菌的感染形式通过消化泡感染宿主大核，并在细胞核中感染后两天分化为生殖形式。单克隆抗体IF-3-1和IF-3-2分别与39和15 kDa的周质蛋白反应，这些蛋白对H的感染形式具有特异性。奥布鲁萨因为在细菌的繁殖形式中没有检测到抗原，所以似乎蛋白质的表达在感染期间或感染后不久减少。使用这些抗体，定量变化的抗原在早期感染过程中进行了研究，免疫印迹和免疫金电子显微镜。免疫印迹显示，两种抗原的量在细菌被吞噬到副睾吸虫的消化空泡后1小时内减少，但IF-3-2抗原的量比IF-3-1抗原更早下降。免疫金标记显示，在宿主消化空泡中的细菌中，IF-3-2抗原的水平变得非常低，而IF-3-1抗原的量没有类似的减少。对抗原的可能功能进行了讨论。IF-3-1抗原的浓度降低与周质区的降低平行。
ABSTRACT. The Gram‐negative bacterium Holospora obrusa is a macronucleus‐specific symbiont of the ciliate Paramecium caudatum. The infectious form of this bacterium infects the host macronucleus through digestive vacuoles and differentiates into the reproductive form two days after the infection in the nucleus. The monoclonal antibodies IF‐3–1 and IF‐3–2 reacted with 39 and 1S kDa periplasmic proteins, respectively, that were specific for the infectious form of H. obrusa. Because the antigens were not detected in the reproductive form of the bacterium, it appears that expression of the proteins decreases during or soon after the infection. Using these antibodies, quantitative changes in the antigens in the early infection process were examined by immunoblotting and immunogold electron microscopy. Immunoblotting showed that the amounts of both antigens were reduced within 1 h after the bacteria were engulfed into the digestive vacuoles of the paramecia, but that the amounts of IF‐3–2 antigens declined earlier than the IF‐3–1 antigen. Immunogold labeling showed that the level of IF‐3–2 antigens became very low in the bacteria in the host digestive vacuoles, whereas there was no similar decrease in amount of IF‐3–1 antigens. Possible functions of the antigens are discussed. The IF‐3–1 antigens decrease in concentration in parallel with the decrease in the periplasmic region.