Bharti Daizy, Kumar Santosh, La Terza Antonietta
School of Biosciences and Veterinary Medicine, Laboratory of Animal and Molecular Ecology, University of Camerino, Via Gentile III da Varano, Camerino 62032, MC, Italy.
Department of Biological Sciences, College of Natural Sciences, University of Ulsan, Ulsan 44610, South Korea.
J Eukaryot Microbiol. 2017 Sep;64(5):678-690. doi: 10.1111/jeu.12404. Epub 2017 Mar 19.
The morphology and morphogenesis during cell division of a new stylonychine hypotrich, Rigidocortex quadrinucleatus n. sp., were investigated using live observation and protargol staining. The new species was isolated from soil samples collected from an organic farm in the Marche Region, Italy, in framework of the MOSYSS project. Rigidocortex quadrinucleatus is characterized as follows: cell size about 180 × 80 μm in vivo; four ellipsoidal macronuclear nodules; 44 adoral membranelles: 18 fronto-ventral-transverse cirri consisting of three frontal, four frontoventral, one buccal, three ventral, two pretransverse, and five transverse cirri; dorsal kinety 3 with multiple fragmentation; resting cyst with hyaline ridges. Rigidocortex quadrinucleatus mainly differs from the type species R. octonucleatus in having four (vs. eight) macronuclear nodules. Rigidocortex quadrinucleatus can be easily confused with Sterkiella cavicola since both have a rather similar ventral ciliature; however, they can be separated by the slightly higher number of cirri in the left marginal row that runs along the posterior cell's margin in R. quadrinucleatus. Morphogenesis on the ventral surface is highly similar to that of Sterkiella species, but differs significantly on the dorsal surface (multiple vs. simple fragmentation of dorsal kinety 3). Phylogenetic analyses based on SSU rRNA gene sequences consistently place the new species within the stylonychine oxytrichids, clustering closer to Gastrostyla steinii than to S. cavicola.
利用活体观察和原银染色法，对一种新的硬皮目裸腹亚目纤毛虫——四核硬皮虫（Rigidocortex quadrinucleatus n. sp.）细胞分裂过程中的形态学和形态发生进行了研究。在MOSYSS项目框架下，从意大利马尔凯地区一个有机农场采集的土壤样本中分离出了该新物种。四核硬皮虫的特征如下：活体状态下细胞大小约为180×80μm；有四个椭圆形大核结节；44片口围小膜；18根额腹横纤毛，由三根额纤毛、四根额腹纤毛、一根颊纤毛、三根腹纤毛、两根前横纤毛和五根横纤毛组成；第3列背纤毛有多次断裂；休眠包囊有透明嵴。四核硬皮虫与模式种八核硬皮虫（R. octonucleatus）的主要区别在于有四个（而非八个）大核结节。四核硬皮虫可能容易与卡维可斯特基虫（Sterkiella cavicola）混淆，因为二者腹面纤毛结构颇为相似；然而，它们可通过四核硬皮虫中沿着细胞后部边缘排列的左缘列纤毛数量略多来区分。腹面的形态发生与斯特基虫属物种高度相似，但在背面有显著差异（第3列背纤毛多次断裂与单次断裂）。基于小亚基核糖体RNA基因序列的系统发育分析始终将该新物种置于硬皮目裸腹亚目纤毛虫类群中，与施泰因氏腹柱虫（Gastrostyla steinii）的聚类关系比与卡维可斯特基虫更近。
