Simakova Anastasia V, Vossbrinck Charles R, Andreadis Theodore G
Tomsk State University, Lenina Street, 32, Tomsk 634050, Russia.
J Invertebr Pathol. 2008 Nov;99(3):302-11. doi: 10.1016/j.jip.2008.07.004. Epub 2008 Jul 25.
A new genus and species of microsporidia, Andreanna caspii n. gen., n. sp. is described from the mosquito, Ochlerotatus caspius (Pallas) based on ultrastructural morphology, developmental characteristics, and comparative sequence analyses of the small subunit (SSU) ribosomal DNA (rDNA). Parasite development is confined to fat body tissue and infected larvae appear swollen with dull white masses within the thorax and abdomen. Meronts have diplokaryotic nuclei and are delineated by a simple plasmalemma contiguous with the host cell cytoplasm. Merogony occurs by synchronous binary division followed by cytokinesis. Diplokaryotic sporonts undergo meiosis and synchronous nuclear division forming sporogonial plasmodia with two, four and eight nuclei enclosed within a persistent sporophorous vesicle. Cytokinesis of sporogonial plasmodia results in the formation of eight uninucleate spores. The episporontal space of early sporonts is filled with a homogeneous accumulation of electron dense granular inclusions and ovoid vesicles of various dimensions, transforming into an interwoven matrix during the initial phase of sporogenesis. Spores are oval, uninucleate and measure 4.8+/-0.3 x 3.1+/-0.4 microm (fixed). The spore wall is 260 microm thick with an irregular exospore consisting of two layers (150-170 microm) and a thinner endospore (90-100 microm). The anchoring disk is well developed and is contiguous with a lamellar polaroplast that occupies the anterior third of the spore and possess more narrow lamellae on the posterior end. The polar filament is gradually tapered and arranged in a single row consisting of six coils ranging from 180 to 150 microm in diameter. The posterior vacuole (posterosome) is moderately sized and filled with a matrix of moderate electron density. Phylogenetic analysis of SSU rDNA from A. caspii and 30 other species of microsporidia including 11 genera parasitic in mosquitoes using maximum parsimony, neighbor joining and maximum likelihood methods showed A. caspii to be a sister group to the clade containing all of the Amblyospora species, including Culicospora, Edhazardia and Intrapredatorus, as well as Culicosporella and Hyalinocysta thus providing strong support for establishment of Andreanna as a separate genus.
基于超微结构形态、发育特征以及小亚基（SSU）核糖体DNA（rDNA）的比较序列分析，从库蚊（Ochlerotatus caspius (Pallas)）中描述了一种微孢子虫的新属新种——卡氏安德雷微孢子虫（Andreanna caspii n. gen., n. sp.）。寄生虫的发育局限于脂肪体组织，受感染的幼虫胸部和腹部出现肿胀，有灰白色团块。裂殖体有双核，由与宿主细胞细胞质相连的简单质膜界定。裂体生殖通过同步二分裂继以胞质分裂进行。双核孢子母细胞进行减数分裂和同步核分裂，形成孢子母质体，其内含两个、四个和八个细胞核，被一个持久的孢子囊包裹。孢子母质体的胞质分裂导致形成八个单核孢子。早期孢子母细胞的孢子周质空间充满电子致密颗粒状内含物和各种尺寸的卵圆形囊泡的均匀积累，在孢子形成的初始阶段转变为交织的基质。孢子呈椭圆形，单核，大小为4.8±0.3×3.1±0.4微米（固定后）。孢子壁厚260微米，外孢子不规则，由两层（150 - 170微米）组成，内孢子较薄（90 - 100微米）。锚定盘发育良好，与占据孢子前三分之一的层状极质体相连，极质体后端的片层较窄。极丝逐渐变细，排成单排，由六个直径从180到150微米的螺旋组成。后液泡（后体）大小适中，充满中等电子密度的基质。使用最大简约法、邻接法和最大似然法对卡氏安德雷微孢子虫以及包括寄生于蚊子的11个属在内的其他30种微孢子虫的SSU rDNA进行系统发育分析，结果显示卡氏安德雷微孢子虫是包含所有安布罗孢属物种（包括库利孢属、埃氏孢属和内捕食孢属）以及库利孢菌属和透明孢囊属的进化枝的姐妹群，从而为将安德雷微孢子虫确立为一个独立属提供了有力支持。
