Itoh Naoki, Komiyama Hideki, Ueki Noriyuki, Ogawa Kazuo
Laboratory of Fish Diseases, Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1, Yayoi, Bunkyo Tokyo 113-8657, Japan.
Int J Parasitol. 2004 Sep;34(10):1129-35. doi: 10.1016/j.ijpara.2004.06.001.
A paramyxea, Marteilioides chungmuensis, causes the irregular enlargement of the ovary in the Pacific oyster, Crassostrea gigas in Korea and Japan. The knowledge about the life cycle of the parasite has been limited to the sporulation stages within the oocyte of oysters. In this study, we used the parasite-specific DNA probes and electron microscopy to experimentally infected oysters in a field and successfully clarified early developmental stages of the parasite. The parasite invaded the oysters through the epithelial tissues of the gills, mantle and labial palps. Extrasporogony repeatedly occurred in the connective tissues by binary fusion. The inner cell of the extrasporogonic stage migrated into the gonadal epithelium, invaded the oocyte to start sporulation.
一种帕拉黏体虫，即忠武帕拉黏体虫（Marteilioides chungmuensis），会导致韩国和日本的太平洋牡蛎（Crassostrea gigas）卵巢出现不规则肿大。关于这种寄生虫生命周期的了解一直局限于牡蛎卵母细胞内的孢子形成阶段。在本研究中，我们使用寄生虫特异性DNA探针和电子显微镜对野外的牡蛎进行实验性感染，并成功阐明了该寄生虫的早期发育阶段。该寄生虫通过鳃、外套膜和唇瓣的上皮组织侵入牡蛎。在结缔组织中，通过二元融合反复发生胞外孢子生殖。胞外孢子生殖阶段的内部细胞迁移到性腺上皮，侵入卵母细胞开始孢子形成。
