Becnel J J, Jeyaprakash A, Hoy M A, Shapiro A
Center for Medical, Agricultural and Veterinary Entomology, USDA/ARS, P.O. Box 14565, Gainesville, FL 32604, USA.
J Invertebr Pathol. 2002 Mar;79(3):163-72. doi: 10.1016/s0022-2011(02)00032-0.
A new microsporidian species is described from the predatory mite Metaseiulus (formerly Typhlodromus or Galendromus) occidentalis (Nesbitt) (Acari, Phytoseiidae). The ultrastructure of this new species is presented together with the first molecular characterization for a microsporidium of mites. All stages of this new microsporidium are haplokaryotic and develop in direct contact with the host-cell cytoplasm. Sporogony is disporoblastic and spores are formed in eggs, immature stages, and adults of M. occidentalis. There are two morphological classes of spores, one with a short polar filament (3-5 coils) that measured 2.53 x 1.68 microm and one with a longer polar filament (8-9 coils) that measured 3.14 x 1.77 microm. Horizontal transmission of this new species occurs by cannibalism of eggs and other stages and perhaps involves the spores with the long polar filament. Spores with the short polar filament may play a role in autoinfection and vertical (transovarial) transmission that is highly efficient in transferring the microsporidium from adults to progeny. Analysis of the small subunit ribosomal DNA indicated that this species from M. occidentalis is most closely related to the Nosema/Vairimorpha clade of microsporidia. A conflict between the morphological and molecular data is discussed. The species is compared to previously described microsporidia of arachnids resulting in creation of Oligosporidium occidentalis n. sp. in the family Unikaryonidae.
从捕食性螨西方盲走螨（Metaseiulus，以前称为盲走螨属或加氏盲走螨属（Typhlodromus或Galendromus） occidentalis（Nesbitt）（蜱螨亚纲，植绥螨科）中描述了一种新的微孢子虫物种。本文展示了该新物种的超微结构，并首次对螨类微孢子虫进行了分子特征分析。这种新微孢子虫的所有阶段均为单倍体核型，在发育过程中与宿主细胞的细胞质直接接触。孢子形成是双孢子型的，孢子在西方盲走螨的卵、未成熟阶段和成体中形成。有两种形态类型的孢子，一种具有短极丝（3 - 5圈），大小为2.53×1.68微米，另一种具有较长极丝（8 - 9圈），大小为3.14×1.77微米。该新物种通过卵和其他阶段的同类相食进行水平传播，可能涉及具有长极丝的孢子。具有短极丝的孢子可能在自身感染和垂直（经卵）传播中起作用，垂直传播在将微孢子虫从成体传递到后代方面效率极高。对小亚基核糖体DNA的分析表明，来自西方盲走螨的该物种与微孢子虫的 Nosema/Vairimorpha 进化枝关系最为密切。文中讨论了形态学和分子数据之间的冲突。将该物种与先前描述的蛛形纲微孢子虫进行了比较，从而在单核科中创建了西方寡孢子虫（Oligosporidium occidentalis）新种。
