Gamazo C, Moriyón I
Infect Immun. 1987 Mar;55(3):609-15. doi: 10.1128/iai.55.3.609-615.1987.
Rough and smooth strains of Brucella melitensis released a membranous material that was devoid of detectable NADH oxidase and succinic dehydrogenase activity (cytoplasmic membrane markers) but that contained lipopolysaccharide, proteins, and phospholipids. This material was composed of two fractions that had similar chemical compositions but that were of different sizes which were separated by differential ultracentrifugation. Electron microscopy showed that both fractions are made of unit membrane structures. The membrane fragments were released during the exponential phase of growth, and no leakage of malic dehydrogenase activity (cytosol marker) was detected. Thus, the fragments were unlikely a result of cell lysis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis showed that, although group 2 Brucella outer membrane proteins and lipoprotein were not detected, the proteins in the membranous material were outer membrane proteins. Gas-liquid chromatography analysis showed a similar fatty acid profile for the cell envelope and the outer membrane fragments of the smooth strain B. melitensis 16M. In contrast, the outer membrane fragments from the rough 115 strain were enriched in palmitic and stearic acids. With respect to the unfractionated cell envelope, outer membrane fragments were enriched in phosphatidylcholine, a phospholipid that is unusual in bacterial membranes.
羊种布鲁氏菌的粗糙型和平滑型菌株释放出一种膜状物质，该物质缺乏可检测到的NADH氧化酶和琥珀酸脱氢酶活性（细胞质膜标记物），但含有脂多糖、蛋白质和磷脂。这种物质由两个部分组成，它们具有相似的化学组成，但大小不同，通过差速超速离心法分离。电子显微镜显示这两个部分均由单位膜结构组成。膜片段在生长的指数期释放，未检测到苹果酸脱氢酶活性（胞质溶胶标记物）的泄漏。因此，这些片段不太可能是细胞裂解的结果。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白质印迹分析表明，虽然未检测到2组布鲁氏菌外膜蛋白和脂蛋白，但膜状物质中的蛋白质是外膜蛋白。气液色谱分析显示，羊种布鲁氏菌16M光滑型菌株的细胞包膜和外膜片段具有相似的脂肪酸谱。相比之下，粗糙型115菌株的外膜片段富含棕榈酸和硬脂酸。就未分级的细胞包膜而言，外膜片段富含磷脂酰胆碱，这是一种在细菌膜中不常见的磷脂。
