Fusco A C, Salafsky B, Kevin M B
Exp Parasitol. 1985 Feb;59(1):44-50. doi: 10.1016/0014-4894(85)90055-4.
Cercariae of Schistosoma mansoni are stimulated to penetrate skin by certain free fatty acids. The cercariae have an active arachidonate cascade, presumably using host skin essential fatty acids as cascade precursors. Exposing cercariae to 3.3 mM linoleate for 1, 10, and 60 min resulted in production of a wide variety of eicosanoids. Using high-performance liquid chromatography, eicosanoids coeluting with prostaglandin E2, D2, and A2, leukotriene B4, and 5-hydroxyeicosatetraenoic acid standards were identified, as well as unidentified peak positions. Radioimmunoassay confirmed the presence of immunoreactive prostaglandin E1, and E2, and 5- and 15-hydroxyeicosatetraenoic acids in cercarial extracts. No eicosanoid production occurred when cercariae were exposed to 3.3 mM oleate and 1 or 330 microM linoleate. Both high-performance liquid chromatography and radioimmunoassay data indicated that cercariae regulate the production of eicosanoids through time. It is postulated that arachidonate metabolism and subsequent eicosanoid production are required for successful cercarial penetration.
曼氏血吸虫尾蚴会被某些游离脂肪酸刺激从而穿透皮肤。尾蚴具有活跃的花生四烯酸级联反应，推测其利用宿主皮肤中的必需脂肪酸作为级联反应的前体物质。将尾蚴暴露于3.3 mM的亚油酸中1分钟、10分钟和60分钟，会导致产生多种类二十烷酸。使用高效液相色谱法，鉴定出了与前列腺素E2、D2和A2、白三烯B4以及5-羟基二十碳四烯酸标准品共洗脱的类二十烷酸，以及未鉴定出的峰位置。放射免疫测定法证实了尾蚴提取物中存在免疫反应性前列腺素E1、E2以及5-和15-羟基二十碳四烯酸。当尾蚴暴露于3.3 mM的油酸以及1或330 μM的亚油酸中时，未发生类二十烷酸的产生。高效液相色谱法和放射免疫测定法的数据均表明，尾蚴会随时间调节类二十烷酸的产生。据推测，花生四烯酸代谢及随后的类二十烷酸产生是尾蚴成功穿透所必需的。
