Stentiford G D, Feist S W, Bateman K S, Hine P M
Centre for Environment, Fisheries and Aquaculture Science (CEFAS), The Nothe, Weymouth, Dorset DT4 8UB, UK.
Dis Aquat Organ. 2004 Apr 21;59(1):57-68. doi: 10.3354/dao059057.
A protozoan parasite with some features of haplosporidians is described from the European shore crab Carcinus maenas. The parasite establishes a systemic infection through the haemal sinuses and connective tissues. Intracellular stages of the parasite were found within reserve inclusion, connective tissue, and muscle cells, while free forms were present in all haemal spaces. A uninucleate stage appeared to develop to a multinucleate plasmodial stage following multiple mitotic divisions of the nucleus. Histopathology also indicated that nuclear division may occur to form multinucleate plasmodia, in connective tissue, reserve inclusion and muscle cells, the multinucleate plasmodium being enclosed in the host-cell plasma membrane. It appears that the multinucleate plasmodium may then undergo internal cleavages which result in plasmodial fragmentation to form many uninucleate stages. Both stages, but particularly the uninucleate stage, contained cytoplasmic, large, ovoid, dense vesicles (DVs), some of which contained an internal membrane separating the medulla from the cortex, as in haplosporosomes. Golgi-like cisternae, closely associated with the nuclear membrane, formed DVs and haplosporosome-like bodies (HLBs), superficially resembling viruses. Infrequently, HLBs may condense to form haplosporosomes. The DVs, as in spores of some Haplosporidium spp. and paramyxeans, may give rise to, and are homologous with, haplosporosomes. Other features, such as the presence of an intranuclear mitotic spindle, lipid droplets, and attachment of DVs and haplosporosomes to the nuclear membrane, indicate that the C. maenas parasite is a haplosporidian. A similar organism reported from the haemolymph of spot prawns Pandalus spp., and haplosporidians reported from prawns Penaeus vannamei and crabs Callinectes sapidus may belong to this group. It is concluded that the well-characterised haplosporidians of molluscs and some other invertebrates may not be characteristic of the whole phylum, and that morphologically and developmentally similar organisms may also be haplosporidians, whether they have haplosporosomes or not.
从欧洲岸蟹（Carcinus maenas）中发现了一种具有单孢子虫某些特征的原生动物寄生虫。该寄生虫通过血窦和结缔组织建立全身感染。在储备内含物、结缔组织和肌肉细胞内发现了寄生虫的细胞内阶段，而在所有血腔中都存在游离形式。单核阶段似乎在细胞核多次有丝分裂后发展为多核的疟原虫阶段。组织病理学还表明，在结缔组织、储备内含物和肌肉细胞中，核分裂可能会发生以形成多核疟原虫，多核疟原虫被包裹在宿主细胞质膜内。似乎多核疟原虫随后可能会进行内部裂解，导致疟原虫破碎形成许多单核阶段。两个阶段，尤其是单核阶段，都含有细胞质的、大的、卵形的、致密的囊泡（DVs），其中一些囊泡含有将髓质与皮质分开的内膜，就像在单孢子体中一样。与核膜紧密相关的高尔基体样扁平囊形成了DVs和单孢子体样体（HLBs），表面上类似于病毒。HLBs偶尔可能会浓缩形成单孢子体。与某些单孢子虫属和副粘菌的孢子一样，DVs可能会产生单孢子体并与之同源。其他特征，如核内有丝分裂纺锤体的存在、脂滴以及DVs和单孢子体与核膜的附着，表明C. maenas寄生虫是一种单孢子虫。从斑节对虾（Pandalus spp.）血淋巴中报道的一种类似生物，以及从凡纳滨对虾（Penaeus vannamei）和青蟹（Callinectes sapidus）中报道的单孢子虫可能属于这一类群。得出的结论是，软体动物和其他一些无脊椎动物中特征明显的单孢子虫可能并非整个门的特征，并且形态和发育相似的生物也可能是单孢子虫，无论它们是否有单孢子体。
