School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul 151 747, Korea.
J Eukaryot Microbiol. 2011 Jul-Aug;58(4):284-309. doi: 10.1111/j.1550-7408.2011.00544.x. Epub 2011 Apr 29.
The heterotrophic dinoflagellate Gyrodiniellum shiwhaense n. gen., n. sp. is described from live cells and from cells prepared for light, scanning electron, and transmission electron microscopy. Also, sequences of the small subunit (SSU) and large subunit (LSU) of rDNA have been analyzed. The episome is conical, while the hyposome is ellipsoid. Cells are covered with polygonal amphiesmal vesicles arranged in 16 horizontal rows. Unlike other Gyrodinium-like dinoflagellates, the apical end of the cell shows a loop-shaped row of five elongate amphiesmal vesicles. The cingulum is displaced by 0.3-0.5 × cell length. Cells that were feeding on the dinoflagellate Amphidinium carterae Hulburt were 9.1-21.6 μm long and 6.6-15.7 μm wide. Cells of G. shiwhaense contain nematocysts, trichocysts, a peduncle, and pusule systems, but they lack chloroplasts. The SSU rDNA sequence is >3% different from that of the six most closely related species: Warnowia sp. (FJ947040), Lepidodinium viride Watanabe, Suda, Inouye, Sawaguchi & Chihara, Gymnodinium aureolum (Hulburt) Hansen, Gymnodinium catenatum Graham, Nematodinium sp. (FJ947039), and Gymnodinium sp. MUCC284 (AF022196), while the LSU rDNA is 11-12% different from that of Warnowia sp., G. aureolum, and Nematodinium sp. (FJ947041). The phylogenetic trees show that the species belongs in the Gymnodinium sensu stricto clade. However, in contrast to Gymnodinium spp., cells lack nuclear envelope chambers and a nuclear fibrous connective. Unlike Polykrikos spp., cells of which possess a taeniocyst-nematocyst complex, G. shiwhaense has nematocysts but lacks taeniocysts. It differs from Paragymnodinium shiwhaense Kang, Jeong, Moestrup & Shin by possessing nematocysts with stylets and filaments. Gyrodiniellum shiwhaense n. gen., n. sp. furthermore lacks ocelloids, in contrast to Warnowia spp., Nematodinium spp., and Proterythropsis spp. Based on morphological and molecular data, we suggest that the taxon represents a new species within a new genus.
本文描述了一种异养性的旋沟藻属浮游生物——史氏旋沟藻，该藻种的活细胞和经过光镜、扫描电镜和透射电镜处理的细胞都可以用于描述和分析。同时，还对小亚基（SSU）和大亚基（LSU）rDNA 序列进行了分析。内体呈锥形，而外体呈椭圆形。细胞被排列成 16 个水平行的多边形囊泡覆盖。与其他类似 Gyrodinium 的甲藻不同，细胞的顶端显示出五组长而窄的多边形囊泡的环型排列。冠环位移 0.3-0.5×细胞长度。以角藻属（Amphidinium carterae Hulburt）为食的史氏旋沟藻细胞长 9.1-21.6μm，宽 6.6-15.7μm。史氏旋沟藻细胞含有刺丝囊、粘丝囊、柄和毒囊系统，但缺乏叶绿体。SSU rDNA 序列与六个最密切相关的物种（FJ947040 种 Warnowia、Watanabe、Suda、Inouye、Sawaguchi 和 Chihara 的绿点甲藻、Hulburt 的金黄旋沟藻、Graham 的链状亚历山大藻、FJ947039 种 Nematodinium 和 AF022196 种 Gymnodinium sp. MUCC284）的差异超过 3%，而 LSU rDNA 序列与 Warnowia、金黄旋沟藻和 Nematodinium（FJ947041）的差异为 11-12%。系统发育树显示该物种属于 Gymnodinium 严格意义上的分支。然而，与 Gymnodinium 属不同，细胞缺乏核膜室和核纤维连接。与多甲藻属不同，后者的细胞具有盔刺丝囊-粘丝囊复合体，史氏旋沟藻只有刺丝囊而没有盔刺丝囊。与 Kang、Jeong、Moestrup 和 Shin 的拟旋沟藻不同，史氏旋沟藻具有具刺和丝的刺丝囊。此外，与 Warnowia 属、Nematodinium 属和 Proterythropsis 属不同，史氏旋沟藻属没有眼点。基于形态学和分子数据，我们认为该分类群代表了一个新属中的一个新种。
