Benolken R M, Anderson R E, Maude M B
Biochim Biophys Acta. 1975 Dec 1;413(2):234-42. doi: 10.1016/0005-2736(75)90107-8.
The lipid composition has been determined for rhabdomeric photoreceptor membranes of Limulus, and these data are compared with those from photoreceptor membranes of albino rats. The comparison is of interest because the membranes of these two photoreceptor cells regulate ionic transport differently during the response to illumination. 1. Phospholipid class composition of Limulus is similar, but not identical, to that of rats. The major differences are a greater percentage of sphingomyelin in Limulus and a greater percentage of phosphatidylethanolamine in the rat. 2. Ethanolamine plasmalogens, not observed in rat photoreceptor membranes, are present in Limulus photoreceptor fractions. 3. The level of cholesterol in Limulus is higher than that usually reported for vertebrate rod outer segments. 4. The predominant polyunsaturated fatty acids of Limulus photoreceptor membrane phospholipids are 20: 4(n-6) and 20: 5(n-3) with only traces of 22: 6(n-3). This is in sharp contrast with the large percentages of 22: 6(n-3) found in rat photoreceptors. 5. The fatty acid distributions of both membrane systems are highly unsaturated, but the ratio of (n-3) to (n-6) polyunsaturates is only 1.7 for Limulus as compared to 4.6 for rat.
已测定了鲎复眼小网膜感光细胞膜的脂质组成，并将这些数据与白化大鼠感光细胞膜的数据进行了比较。这种比较很有意义，因为这两种感光细胞的膜在光照响应过程中对离子运输的调节方式不同。1. 鲎的磷脂类组成与大鼠的相似，但不完全相同。主要差异在于鲎中鞘磷脂的百分比更高，而大鼠中磷脂酰乙醇胺的百分比更高。2. 大鼠感光细胞膜中未观察到的乙醇胺缩醛磷脂存在于鲎感光细胞组分中。3. 鲎中的胆固醇水平高于通常报道的脊椎动物视杆外段的水平。4. 鲎感光细胞膜磷脂的主要多不饱和脂肪酸是20:4(n - 6)和20:5(n - 3)，只有微量的22:6(n - 3)。这与在大鼠感光细胞中发现的大量22:6(n - 3)形成鲜明对比。5. 两个膜系统的脂肪酸分布都高度不饱和，但鲎的(n - 3)与(n - 6)多不饱和脂肪酸的比例仅为1.7，而大鼠为4.6。
