Efrati H, Wax Y, Rottem S
Arch Biochem Biophys. 1986 Jul;248(1):282-8. doi: 10.1016/0003-9861(86)90425-x.
The composition of the cell membrane of 20 Acholeplasma laidlawii strains grown under identical conditions was studied and correlated with the capacity of these strains to incorporate cholesterol. Membranes of these strains had similar sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns and contained the same lipid species, but the relative amounts of the major polar lipids varied. Statistical analyses revealed that the glycolipids, monoglucosyldiglyceride, and an unidentified glycolipid (glycolipid-X) succeeded in explaining 90% (R2 = 0.90) of the cholesterol uptake variations. The regression coefficients for both glycolipids were negative (P less than 0.001), indicating that the capacity of A. laidlawii strains for cholesterol incorporation is inversely proportional to the relative amounts of these glycolipids. Accordingly, an increased capacity for cholesterol incorporation was detected upon aging of A. laidlawii cells. The aged cells contained significantly smaller amounts of both monoglucosyldiglyceride and glycolipid-X, and a higher amount of diglucosyldiglyceride. The change in cholesterol incorporation as a response to glycolipid composition and content can be explained by the low solubility of cholesterol in glycolipids as well as by the induction by the sterol molecule of a nonlamellar phase state that will destabilize a membrane structure containing monoglucosyldiglyceride and glycolipid-X.
对在相同条件下培养的20株莱氏无胆甾原体菌株的细胞膜组成进行了研究，并将其与这些菌株摄取胆固醇的能力相关联。这些菌株的细胞膜具有相似的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳图谱，且含有相同的脂质种类，但主要极性脂质的相对含量有所不同。统计分析表明，糖脂、单葡萄糖二甘油酯和一种未鉴定的糖脂（糖脂-X）成功地解释了90%（R2 = 0.90）的胆固醇摄取变化。两种糖脂的回归系数均为负数（P小于0.001），表明莱氏无胆甾原体菌株摄取胆固醇的能力与这些糖脂的相对含量成反比。因此，在莱氏无胆甾原体细胞老化时检测到其摄取胆固醇的能力增强。老化细胞中，单葡萄糖二甘油酯和糖脂-X的含量均显著减少，而二葡萄糖二甘油酯的含量增加。胆固醇摄取随糖脂组成和含量的变化可通过胆固醇在糖脂中的低溶解度以及甾醇分子诱导的非层状相态来解释，这种非层状相态会破坏含有单葡萄糖二甘油酯和糖脂-X的膜结构。
