Kawasaki S, Moriguchi R, Sekiya K, Nakai T, Ono E, Kume K, Kawahara K
Department of Bacteriology, Kitasato Institute, Tokyo, Japan.
J Bacteriol. 1994 Jan;176(2):284-90. doi: 10.1128/jb.176.2.284-290.1994.
From the cell envelope preparation of Sphingomonas paucimobilis two membrane fractions with different densities were separated by sucrose density gradient ultracentrifugation. The high-density fraction contained several major proteins, phospholipids, and glycosphingolipids, which are the only glycolipids of this lipopolysaccharide-lacking gram-negative bacterium. The low-density fraction showed many minor bands of proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and NADH oxidase activity was localized in this fraction. Combined with morphological data of vesicles formed by these membrane fractions, the high-density and low-density fractions were proposed to be an outer membrane and a cytoplasmic membrane, respectively. The localization of the glycosphingolipid was investigated also by means of immunoelectron microscopic analysis using a glycosphingolipid-specific antibody. The glycosphingolipid was shown to localize at the cell envelope, and the antigenic sugar portion was exposed to the bacterial cell surface. From these results the glycosphingolipid was assumed to have a function similar to that of the lipopolysaccharide of other gram-negative bacteria.
从少动鞘氨醇单胞菌的细胞包膜提取物中，通过蔗糖密度梯度超速离心分离出两种不同密度的膜组分。高密度组分包含几种主要蛋白质、磷脂和糖鞘脂，这些是这种缺乏脂多糖的革兰氏阴性细菌仅有的糖脂。低密度组分通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳显示出许多次要的蛋白条带，并且NADH氧化酶活性定位于该组分中。结合这些膜组分形成的囊泡的形态学数据，高密度和低密度组分分别被认为是外膜和细胞质膜。还通过使用糖鞘脂特异性抗体的免疫电子显微镜分析研究了糖鞘脂的定位。结果表明糖鞘脂定位于细胞包膜，并且抗原性糖部分暴露于细菌细胞表面。根据这些结果，推测糖鞘脂具有与其他革兰氏阴性细菌的脂多糖相似的功能。
