Laboratory of Hydrobiology, Hunan Agricultural University, Changsha 410128, China; Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Invertebr Pathol. 2020 Jun;173:107368. doi: 10.1016/j.jip.2020.107368. Epub 2020 Apr 2.
We report a new microsporidium Jirovecia sinensis sp. n. from a freshwater oligochaete, Branchiura sowerbyi collected in Hongze city, Jiangsu province, East China. Numerous whitish hypertrophied coelomocytes of 0.33-0.59 mm in diameter indicated infection. Transmission electron microscopy observations revealed that all developmental stages were diplokaryotic. The earliest life stages observed were meronts that were in direct contact with host cytoplasm, accumulated peripherally in the hypertrophied coelomocytes and connected with host cytoplasm through many pinocytotic canals. Mature spores are rod-shaped with a blunt end, measuring 17.0 ± 0.1 (14.9-18.5) μm long and 2.0 ± 0.2 (1.7-2.2) μm wide. The most conspicuous character of the novel microsporidian parasite is the tail-like posterior prolongations, with a length of 29.6-40.8 μm. Mature spores have a manubrium with a diameter of 447-485 nm which consist of six density-discontinuous concentric circles. Spores possess a collar-shaped anchoring disk and a bipartite polarplast with an anterior lamellar region and a posterior tubular section. SSU rDNA-based phylogenetic analysis indicated with high support values that the new species clustered with two Bacillidium species (B. vesiculoformis and Bacillidium sp.) infecting the freshwater oligochaetes and Janacekia debaisieuxi infecting the insect Simulium maculatum. Based on the ultrastructural features and molecular characteristics, a new species in the genus Jirovecia, Jirovecia sinensis sp. n., is designated.
我们报道了一种来自中国华东江苏省洪泽市淡水寡毛类环节动物Branchiura sowerbyi 的新的微孢子虫 Jirovecia sinensis sp. n.。大量直径为 0.33-0.59 毫米的白色肥大体腔细胞表明受到了感染。透射电子显微镜观察显示，所有发育阶段都是二倍体。观察到的最早生命阶段是与宿主细胞质直接接触的 meronts，它们在肥大的体腔细胞中聚集在周围，并通过许多胞饮通道与宿主细胞质相连。成熟孢子呈杆状，钝端，长 17.0±0.1（14.9-18.5）μm，宽 2.0±0.2（1.7-2.2）μm。新型微孢子虫寄生虫最显著的特征是尾部样后延伸，长度为 29.6-40.8μm。成熟孢子具有一个长 447-485nm 的杆状柄，由六个密度不连续的同心环组成。孢子具有一个环颈状的锚固盘和一个二分体极质体，前部分为片状，后部分为管状。基于 SSU rDNA 的系统发育分析表明，新物种与感染淡水寡毛类的两种 Bacillidium 物种（B. vesiculoformis 和 Bacillidium sp.）以及感染昆虫 Simulium maculatum 的 Janacekia debaisieuxi 聚类具有高度支持值。根据超微结构特征和分子特征，指定了一个新的 Jirovecia 属物种，即中华 Jirovecia sinensis sp. n.。
