SCHISTOSOMA-MANSONI - ANALYSIS OF CERCARIAL TRANSFORMATION-METHODS
SCHISTOSOMA-MANSONI - ANALYSIS OF CERCARIAL TRANSFORMATION-METHODS
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DOI：
10.1016/0014-4894(88)90014-8
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发表时间：
1988-10-01
影响因子：
2.1
通讯作者：
ELLENBERGER, B
中科院分区：
文献类型：
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作者：
SALAFSKY, B;FUSCO, AC;ELLENBERGER, B
比较了在 ELAC 缓冲液（pH 7.2、37℃、0-6 小时孵育）中体外将尾蚴转化为血吸虫的四种方法的生化和超微结构特征。使用的转化方法是化学（3 mM 亚油酸酯）、机械（离心/涡旋）、机械/化学和加热（37°C 孵育）。检查的超微结构特征基于糖萼、七胺膜、细胞颗粒和核状况的存在或不存在。使用两种 EM 固定方法。测定的生化参数包括耐水性丧失（台盼蓝染料的摄取）、类二十烷酸生物合成（PGE、LTB4和5-HETE）、蛋白质合成（亮氨酸摄取）、RNA合成（尿嘧啶和乳清酸摄取）和DNA合成（胸苷摄取）。除热孵育外，所有转化方法的 EM 特征都非常相似，转化的尾蚴证明了血吸虫的特征（细胞颗粒迁移、缺乏糖萼和七层膜）；然而，使用体内或体外转化方法无法证明常染色质核。尽管转化方法之间的超微结构相似，但生化数据表明所得生物体却截然不同。化学转化方法的耐水性和类二十烷酸产量损失率最高。 RNA和蛋白质合成与超微结构变化无关，并且在接受机械转化方法的生物体中最高，显着高于通过化学方法转化的尾蚴。尽管确实发生了胸苷摄取，但使用任何转化方法均未证明 DNA 合成。我们的数据表明形态相似的生物体之间存在显着的生化差异。因此，在对尾蚴转化进行额外的生化和生理学研究之前，必须谨慎解释使用任何类型的人工转化血吸虫的实验。
Four methods of transforming cercariae to schistosomulae in vitro in ELAC buffer (pH 7.2, 37 C, 0-6 hr incubation) were compared in relation to biochemical and ultrastructural characteristics. The transformation methods used were chemical (3 mM linoleate), mechanical (centrifuge/vortex), mechanical/chemical, and heat (incubation at 37 C). Ultrastructural characteristics examined were based on the presence or absence of glycocalyx, heptalaminate membrane, cyton granules, and nuclear condition. Two EM fixation methods were used. Biochemical parameters assayed were loss of water tolerance (uptake of trypan blue dye), eicosanoid biosynthesis (PGE, LTB4, and 5-HETE), protein synthesis (leucine uptake), RNA synthesis (uracil and orotic acid uptake), and DNA synthesis (thymidine uptake). EM characteristics were remarkably similar for all transformation methods except heat incubation, with transformed cercariae evidencing the characteristics of schistosomulae (cyton granule migration, absence of glycocalyx and heptalaminate membrane); however, euchromatic nuclei could not be demonstrated using in vivo or in vitro transformation methods. Despite the ultrastructural similarities between transformation methods, biochemical data demonstrated that the resultant organisms were quite different. The chemical transformation method gave the highest rate of loss of water tolerance and eicosanoid production. RNA and protein synthesis were not correlated to ultrastructural changes and were highest in those organisms undergoing mechanical transformation methods, significantly higher than in those ceracariae transformed by the chemical method. DNA synthesis was not demonstrated using any transformation method, although thymidine uptake did occur. Our data indicate substantial biochemical differences exist between morphologically similar organisms. Thus, experiments using any type of artificially transformed schistosomule must be interpreted with caution until additional biochemical and physiological studies on cercarial transformation are undertaken.