Young B W, Podesta R B
Mol Biochem Parasitol. 1985 May;15(2):105-14. doi: 10.1016/0166-6851(85)90112-4.
Choline uptake and incorporation into Schistosoma mansoni is used as a model for investigating transport across and formation of a double bilayer surface of a syncytial transporting epithelium. Choline uptake reached a maximal rate during the first 2 min (Vmax = 0.27 mumol mg-1 protein min-1; Km = 36 microM). Choline uptake during a 30 min incubation was similar to that of single bilayer transport systems described in the literature. Choline incorporation into phosphatidylcholine was saturated above 40 microM external choline concentration (Vmax = 3.7 pmol mg-1 protein min-1; Km = 7 microM). The low rate of choline efflux and the half life of the tissue choline pool (T 1/2 = 3 h), suggests that free choline pools available for efflux in S. mansoni are small. This model allows the determination of whether a proposed effector of membrane phosphatidylcholine synthesis and turnover alters surface bilayer formation through changes in transport of the precursor across the apical surface.
胆碱摄取及掺入曼氏血吸虫的过程被用作一个模型，用于研究跨合胞体转运上皮细胞双层表面的转运及该双层表面的形成。胆碱摄取在前2分钟达到最大速率（Vmax = 0.27 μmol mg-1蛋白质 分钟-1；Km = 36 μM）。30分钟孵育期间的胆碱摄取与文献中描述的单双层转运系统相似。在胞外胆碱浓度高于40 μM时，胆碱掺入磷脂酰胆碱达到饱和（Vmax = 3.7 pmol mg-1蛋白质 分钟-1；Km = 7 μM）。胆碱外流速率较低以及组织胆碱池的半衰期（T 1/2 = 3小时）表明，曼氏血吸虫中可用于外流的游离胆碱池较小。该模型能够确定一种拟议的膜磷脂酰胆碱合成及周转效应物是否通过改变前体跨顶端表面的转运来改变表面双层的形成。
