Elam J S, Cancalon P
Neurochem Res. 1987 Mar;12(3):271-7. doi: 10.1007/BF00972137.
A floating fraction that layers on top of 0.25 sucrose has been obtained during the preparation of myelin from intact and 9 day degenerating goldfish optic tracts. The proportion of total tract protein isolated in floating fraction rises from 6.6% to 11.0% during degeneration. This increase is paralleled by a morphologically observed splitting of myelin lamellae. Floating fraction contains all of the major myelin proteins but shows a 40% increase in the proportion of basic protein and a 2-3 fold decrease in the proportion of IP proteins (intermediate molecular weight glycoproteins) and a 36 Kd (X) protein. The lipid to protein ratio is slightly higher in floating fraction than myelin. Lipid composition is characterized by 1/2-1/3 the myelin levels of galactolipids and twofold increased levels of triglycerides and cholesterol esters. Electron microscopy of floating fraction shows a mixture of myelin fragments with few lamellae and single membrane fragments. Taken together the results indicate that floating fraction in the degenerating goldfish optic tract is at least partially derived from the breakdown of myelin.
在从完整的和退化9天的金鱼视神经束制备髓磷脂的过程中，获得了一种漂浮在0.25蔗糖之上的组分。在退化过程中，分离于漂浮组分中的总束蛋白比例从6.6%上升至11.0%。这种增加与在形态学上观察到的髓鞘板层分裂同时出现。漂浮组分包含所有主要的髓磷脂蛋白，但碱性蛋白比例增加40%，IP蛋白（中等分子量糖蛋白）和一种36 Kd（X）蛋白的比例下降2至3倍。漂浮组分中的脂蛋白比略高于髓磷脂。脂质组成的特征是半乳糖脂水平为髓磷脂的1/2至1/3，甘油三酯和胆固醇酯水平增加两倍。漂浮组分的电子显微镜检查显示，有少量板层的髓磷脂碎片和单膜碎片的混合物。综合这些结果表明，退化的金鱼视神经束中的漂浮组分至少部分源自髓磷脂的分解。
