Cousin C, Ofori K, Acholonu S, Miller A, Richards C, Lewis F, Knight M
Biological and Environmental Science Department, University of the District of Columbia, Washington, D.C. 20008, USA.
J Parasitol. 1995 Dec;81(6):905-11.
The LAC-line strain of the snail Biomphalaria glabrata has very low susceptibility to the parasite Schistosoma mansoni and a very low reproductive potential. Upon examination of the reproductive tract of these snails, light and electron microscopy revealed obvious abnormalities in the albumen gland. Secretory cells that are normally cuboidal in susceptible NMRI (F0) snails were squamous in LAC-line snails. These LAC-line cells contained small secretory granules and negligible rough endoplasmic reticulum and Golgi, compared to large granules and an extensive array of both organelles in F0 albumen gland cells. Comparative analyses of soluble protein extracts of F0 and LAC-line albumen glands showed several qualitative differences. Among the most prominent was an 18-kDa protein in F0 snails that was remarkably reduced in the soluble protein extracts of LAC-line snails. Also, metabolic incorporation of [35S]-methionine was impaired in LAC-line albumen glands. Whether these albumen gland changes are caused by decreased susceptibility to parasitism is yet to determined.
光滑双脐螺的LAC系品系对曼氏血吸虫的易感性非常低，且繁殖潜力也很低。在检查这些蜗牛的生殖道时，光学显微镜和电子显微镜检查显示蛋白腺存在明显异常。在易感染的NMRI（F0）蜗牛中通常呈立方形的分泌细胞，在LAC系蜗牛中则为扁平状。与F0蛋白腺细胞中含有大颗粒以及大量这两种细胞器相比，这些LAC系细胞含有小的分泌颗粒，且粗面内质网和高尔基体极少。对F0和LAC系蛋白腺的可溶性蛋白提取物进行的比较分析显示出一些质量上的差异。其中最显著的是F0蜗牛中的一种18 kDa蛋白，在LAC系蜗牛的可溶性蛋白提取物中显著减少。此外，LAC系蛋白腺中[35S] - 蛋氨酸的代谢掺入也受到损害。这些蛋白腺的变化是否由对寄生虫感染易感性降低引起尚待确定。
