University of Cologne, Institute of Zoology, General Ecology, Zuelpicher Str. 47 b, 50674 Cologne, Germany.
Rebikoff-Niggeler Foundation, Rocha Vermelha, Apt. 249, Praia do Almoxarife, 9900-909 Horta, Portugal.
Eur J Protistol. 2019 Jun;69:102-116. doi: 10.1016/j.ejop.2019.02.007. Epub 2019 Mar 6.
New phagotrophic euglenoid species from marine surface waters and the deep sea were isolated and described by light and scanning electron microscopy and 18S rDNA sequencing: Keelungia nitschei, Petalomonas acorensis and Ploeotia costaversata. The morphological characteristics of Keelungia nitschei agree with Keelungia pulex besides the slightly truncated anterior front of the cell of our strain. Phylogenetic analysis indicated low sequence similarity between K. nitschei and K. pulex (87.3%). Ploeotia costaversata clustered within the Ploeotia costata clade with a sequence similarity of 96.1% to P. costata strain Tam. Ultrastructural characteristics of our strain revealed helically twisted strips towards both poles of the protoplast. 18S rDNA phylogenies showed that Petalomonas acorensis is related to the clade of Petalomonas cantuscygni/Scytomonas saepesedens with the highest sequence similarity of 81.2% to P. cantuscygni. Six pellicle strips are visible, while two of them reach only the middle of the cell and four (two longitudinal, two helically twisted) join at the posterior front of the cell. Pressure experiments showed that the deep-sea strain K. nitschei was better adapted to high hydrostatic pressures (up to 500 bar) at 4 °C than the two surface water strains. All three strains increased the database (18S rDNA) of the underrepresented group of phagotrophic euglenids.
从海洋表面和深海中分离并通过光镜和扫描电镜以及 18S rDNA 测序描述了新的吞噬性腰鞭毛虫物种：基隆鞭毛虫、海毛藻和 costaversata 普洛蒂亚。基隆鞭毛虫的形态特征除了我们的菌株细胞的前前端稍截断外，与 pulex 基隆鞭毛虫一致。系统发育分析表明，K. nitschei 和 K. pulex 之间的序列相似性较低（87.3%）。Ploeotia costaversata 与 Ploeotia costata 分支聚类，与 P. costata Tam 菌株的序列相似性为 96.1%。我们的菌株的超微结构特征显示原生质体向两个极螺旋扭曲条带。18S rDNA 系统发育表明，Petalomonas acorensis 与 Petalomonas cantuscygni/Scytomonas saepesedens 分支相关，与 P. cantuscygni 的序列相似性最高，为 81.2%。可见 6 条纤毛带，其中 2 条仅到达细胞中部，4 条（2 条纵向，2 条螺旋扭曲）在细胞后前端连接。压力实验表明，深海菌株 K. nitschei 在 4°C 时比两种表面水菌株更能适应高达 500 巴的高静压。这三种菌株都增加了数据库（18S rDNA）中吞噬性腰鞭毛虫代表性不足的群体。
