Stentiford G D, Ross S, Minardi D, Feist S W, Bateman K S, Gainey P A, Troman C, Bass D
Pathology and Microbial Systematics Theme,Cefas Weymouth Laboratory,Weymouth,Dorset DT4 8UB,UK.
Polwithen Road,Penryn TR10 8QT,Cornwall,UK.
Parasitology. 2018 Jul;145(8):1105-1117. doi: 10.1017/S0031182017002256. Epub 2017 Dec 18.
Within aquatic habitats, the hyper-abundant Order Crustacea appear to be the predominant host group for members of the Phylum Microsporidia. The musculature, a common site of infection, provides access to biochemical (carbohydrate-rich) and physiological (mitochondria-rich) conditions conducive to prolific parasite replication and maturation. The significant proportion of body plan devoted to skeletal musculature in Crustacea provides the location for a highly efficient intracellular parasite factory. In this study, we utilize histological, ultrastructural and phylogenetic evidence to describe a previously known (Inodosporus octospora) and novel (Ovipleistophora arlo n. sp.) microsporidian parasites infecting the musculature of the common prawn (Palaemon serratus) from the same site, at the same time of year. Despite similar clinical signs of infection, both parasites are otherwise distinct in terms of pathogenesis, morphology and phylogeny. Based upon partial subunit ribosomal RNA (SSU rDNA) sequence, we show that that I. octospora may be identical to a Kabatana sp. previously described infecting two-spot goby (Gobiusculus flavescens) in Europe, or at least that Inodosporus and Kabatana genera are synonyms. In addition, SSU rDNA sequence for O. arlo places it within a distinct clade containing Ovipleistophora mirandellae and Ovipleistophora ovariae, both infecting the oocytes of freshwater fish in Europe. Taken together, our data provide strong evidence for trophic-transfer between crustacean and fish hosts for two different microsporidians within clade 5 of the phylum. Furthermore, it demonstrates that morphologically and phylogenetically distinct microsporidians can infect the same tissues of the same host species to impart clinical signs which mimic infection with the other.
在水生栖息地中，数量超多的甲壳纲似乎是微孢子虫门成员的主要宿主群体。肌肉组织是常见的感染部位，为寄生虫大量繁殖和成熟提供了有利于生化反应（富含碳水化合物）和生理活动（富含线粒体）的条件。甲壳纲动物身体结构中很大一部分是骨骼肌，为高效的细胞内寄生虫工厂提供了场所。在本研究中，我们利用组织学、超微结构和系统发育学证据，描述了两种感染同一年同一地点普通对虾（Palaemon serratus）肌肉组织的微孢子虫寄生虫，一种是先前已知的（八孢内孢虫，Inodosporus octospora），另一种是新发现的（阿洛卵孢虫，Ovipleistophora arlo n. sp.）。尽管两种寄生虫感染的临床症状相似，但在发病机制、形态和系统发育方面存在明显差异。基于部分小亚基核糖体RNA（SSU rDNA）序列，我们发现八孢内孢虫可能与之前在欧洲描述的一种感染双斑虾虎鱼（Gobiusculus flavescens）的卡巴塔虫属（Kabatana sp.）相同，或者至少内孢虫属（Inodosporus）和卡巴塔虫属是同义词。此外，阿洛卵孢虫的SSU rDNA序列表明它属于一个独特的进化枝，该进化枝包含感染欧洲淡水鱼卵母细胞的米兰德卵孢虫（Ovipleistophora mirandellae）和卵巢卵孢虫（Ovipleistophora ovariae）。综合来看，我们的数据有力地证明了该门第5进化枝内两种不同微孢子虫在甲壳类宿主和鱼类宿主之间存在营养转移。此外，研究表明形态和系统发育上不同的微孢子虫可以感染同一宿主物种的相同组织，引发类似另一种微孢子虫感染的临床症状。
