鱼腥藻细胞外膜完整性与防氧的关系  

RELATION OF INTEGRITY OF OUTER MEMBRANE WITH ITS PROTECTION FROM OXYGEN IN ANABAENA CELL

作　　者：王业勤[1] 冯渤[1] 黎尚豪[1] 

机构地区：[1]中国科学院水生生物研究所

出　　处：《Acta Botanica Sinica》1989年第4期265-272,共8页Acta Botanica Sinica（植物学报：英文版）

基　　金：中国科学院科学基金~~

摘　　要：暴露鱼腥藻7120(Anabaena 7120)细胞于膜扰乱剂EDTA或Tris(pH 8.0,37℃,5—10分钟),导致细胞释放外膜脂多糖和蛋白成分。Tris处理后,细胞对结晶紫和洗涤剂(SDS,Triton X-100)的敏感性增加,整细胞碱性磷酸酶活性增强,暗示外膜结构被修饰,透过性增大;与此同时,被处理细胞固氮酶活性在空气氧中大大降低,而在厌氧条件下活性不受影响。将细胞释放物质与处理后的细胞重组时,可明显恢复固氮活性,表明外膜结构与固氮防氧保护有密切关系。EDTA处理的细胞,虽然释放的脂多糖和蛋白量较多,但对外膜透过性和固氮活性的影响较小。电泳分析表明,Tris处理,细胞释放3—4种特异性多肽,可能是特定部位或结构被修饰。Exposure of Anabaena 7120 cells to membrane perturbant such as EDTA or Tris (pH 8.0, 37℃, for 5--10 min) resulted in the release of outer membrane lipopolysaccharide and proteins from cells. After Tris treatment, the sensitivity of cells to crystal violet and detergents such as SDS and Triton x--100 increased and whole-cell alkaline phosphatase activity enhanced obviously, suggesting that the structure of outer membrane was modified and its permeability increased. At the same time. Tris was found to reduce nitrogen fixation activity of cells considerably in air, but not in anaerobic condition. Reconstitution of Tris-treated cells with released material might recover nitrogen-fixing activity of cells clearly, indicating that the struc- ture of outer membrane is closely related to the protection of nitrogen fixation from oxygen. Although EDTA-treated cells released more lipopolysacharide and proteins than those of Tris-treated cells, the permeability of outer membrane and nitrogen-fixing activity were not influenced significantly. SDS-gel electrophoresis showed that Tris-treated cells released 3-4 specific polypeptides which were not present in the released material from EDTA-treated or water-treated cells. These experiments suggest that membrane perturbants-induced loss of outer membrane function is mediated through the modification of specific position in outer membrane.

关 键 词：鱼腥藻 外膜 固氮氧保护 

分 类 号：Q945.13[生物学—植物学]