Hunan Engineering Research Center for Utilization of Characteristics of Aquatic Resources, Hunan Agricultural University, Changsha 410128, China.
International Centre of Excellence for Aquatic Animal Health, Cefas Weymouth Laboratory, Dorset, Weymouth DT4 8UB, UK; Centre for Sustainable Aquaculture Futures, College of Life and Environmental Sciences, Geoffrey Pope, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
J Invertebr Pathol. 2022 Jun;191:107768. doi: 10.1016/j.jip.2022.107768. Epub 2022 May 13.
A new microsporidian parasite, Naidispora caidianensis n. gen. n. sp. was found in coelomocytes of oligochaete Branchiura sowerbyi Beddard, 1892 from Wuhan city, Hubei Province, China. Opaque, hypertrophied coelomocytes (0.17-0.24 mm in diameter) depicted clinical signs of infection. Electron microscopy revealed a microsporidian with monokaryotic life stages. Rounded uninucleate meronts subsequently transformed into multinucleate merogonial plasmodia with masses of electron-dense projections on their plasma membrane. Electron-dense sporogonial plasmodia separated into uninucleate sporonts through rosette-like budding, and further developed into sporoblasts, enclosed by a sporophorous vesicle. Uninucleate mature spores were pyriform, measured 4.1 ± 0.1 (3.9-4.3) μm × 2.1 ± 0.07 (1.9-2.2) μm (average ± SE, range, n = 50), and contained a mushroom-like anchoring disk, bipartite polaroplast, electron-lucent posterior vacuole, trilaminar spore wall and 12-14 turns of an isofilar polar filament arranged in 2-3 ranks. The 1542 bp sequence from B. soweryi showed the highest similarity (below 80 %) with Nematocenator marisprofundi (accession number: JX463178). SSU rRNA gene-based phylogenetic analysis demonstrated that the novel taxon formed an independent clade from known microsporidian parasites. Based on the ultrastructural features and SSU rRNA gene sequence, we propose the establishment of a novel genus (Naidispora n. gen.) and species (Naidispora caidianensis n. sp.) to contain this parasite.
一种新的微孢子虫寄生虫，Naidispora caidianensis n. gen. n. sp. 在中国湖北省武汉市的寡毛纲 Branchiura sowerbyi Beddard 中发现于体腔细胞中。不透明、肥大的体腔细胞（直径 0.17-0.24 毫米）表现出感染的临床症状。电子显微镜显示出具有单核生命阶段的微孢子虫。圆形单核的 meronts 随后转化为具有大量电子致密突起的多核 merogonial plasmodia，其质膜上有大量电子致密突起。电子致密的孢子母细胞通过玫瑰花结样出芽分裂成单核孢子原细胞，然后进一步发育成孢子母细胞，被孢子囊泡包围。单核成熟孢子呈梨形，测量值为 4.1 ± 0.1（3.9-4.3）μm×2.1 ± 0.07（1.9-2.2）μm（平均值 ± SE，范围，n=50），并包含一个蘑菇状的锚固盘、二分叉极体、电子透明后液泡、三层孢子壁和 12-14 圈等距排列的丝状极丝。B. soweryi 的 1542 bp 序列与 Nematocenator marisprofundi（登录号：JX463178）具有最高的相似性（低于 80%）。基于 SSU rRNA 基因的系统发育分析表明，新分类群与已知的微孢子虫寄生虫形成一个独立的分支。根据超微结构特征和 SSU rRNA 基因序列，我们建议建立一个新的属（Naidispora n. gen.）和种（Naidispora caidianensis n. sp.）来包含这个寄生虫。
