Vossbrinck Charles R, Debrunner-Vossbrinck Bettina A
Department of Soil and Water, The Connecticut Agricultural Experiment Station, 123 Huntington Street, New Haven, Connecticut 06511, USA.
Folia Parasitol (Praha). 2005 May;52(1-2):131-42; discussion 130. doi: 10.14411/fp.2005.017.
The Microsporidia are a group of obligate intracellular parasites, now thought to be derived fungi. Presented here is a comparative small subunit rDNA (ssrDNA) analysis of 125 species of Microsporidia (sequences obtained from GenBank). This analysis shows that groups or clades are formed based largely on habitat and host. This result is supported by comparative molecular analyses of the past decade, and indicates that structural and ultrastructural characters are unreliable for distinguishing among higher-level microsporidian taxa. Our findings indicate the presence of five major clades of Microsporidia which group according to habitat. We present three new classes of Microsporidia based on natural phylogenetic groupings as illustrated by the ssrDNA analysis: Aquasporidia, Marinosporidia and Terresporidia. The names of the proposed classes reflect the habitat of each group. The class Aquasporidia, found primarily in freshwater habitats, is a paraphyletic group consisting of three clades. The Marinosporidia are found in hosts of marine origin and the Terresporidia are primarily from terrestrial environments.
微孢子虫是一类专性细胞内寄生虫，现在被认为是真菌的衍生物。本文展示了对125种微孢子虫（从基因库获得的序列）的小亚基核糖体DNA（ssrDNA）的比较分析。该分析表明，类群或进化枝的形成主要基于栖息地和宿主。这一结果得到了过去十年比较分子分析的支持，并表明结构和超微结构特征对于区分高级微孢子虫分类群并不可靠。我们的研究结果表明，微孢子虫存在五个主要进化枝，它们根据栖息地进行分组。根据ssrDNA分析所显示的自然系统发育分组，我们提出了微孢子虫的三个新纲：水生微孢子虫纲、海洋微孢子虫纲和陆生微孢子虫纲。所提议纲的名称反映了每个类群的栖息地。主要发现于淡水栖息地的水生微孢子虫纲是一个并系类群，由三个进化枝组成。海洋微孢子虫纲存在于海洋来源的宿主中，而陆生微孢子虫纲主要来自陆地环境。
