Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan; Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa, 237-0061, Japan.
Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa, 237-0061, Japan.
Protist. 2020 Jul;171(3):125731. doi: 10.1016/j.protis.2020.125731. Epub 2020 Apr 25.
Ventrifissura is a group of poorly studied heterotrophic biflagellates in the phylum Cercozoa. Despite a phylogenetic placement with only weak support and a lack of ultrastructural data, Ventrifissura was assigned to Thecofilosea. In the presented study, we established cultures of two novel species of Ventrifissura (V. oblonga n. sp. and V. velata n. sp.) isolated from coastal marine environments in Japan, and performed light and electron microscopy observations and molecular phylogenetic analysis. Transmission electron microscopy revealed that V. oblonga shares several ultrastructural characteristics with thecofilosean flagellates, including permanently condensed chromosomes, a extracellular theca, and slender extrusomes. Molecular phylogenetic analysis could not resolve the phylogenetic position, but the possibility that Ventrifissura clusters into Ventrifilosa was supported by approximately unbiased tests. Based on both morphological and phylogenetic findings, we concluded that Ventrifissura is a basal lineage of Thecofilosea.
旋口虫是肉足鞭毛门涡鞭毛纲中研究较少的异养双鞭毛虫群。尽管旋口虫在系统发育上的位置仅得到微弱支持，并且缺乏超微结构数据，但仍被归为有孔虫目。在本研究中，我们建立了从日本沿海海洋环境中分离出的两种新型旋口虫（V. oblonga n. sp. 和 V. velata n. sp.）的培养物，并进行了光镜和电镜观察以及分子系统发育分析。透射电子显微镜显示，V. oblonga 与有孔虫目鞭毛虫具有一些共同的超微结构特征，包括永久浓缩的染色体、细胞外被和细长的外体。分子系统发育分析无法确定其系统发育位置，但无偏一致检验支持旋口虫可能聚类为旋口虫属。基于形态学和系统发育学的发现，我们得出结论，旋口虫是有孔虫目的一个基础谱系。
