Systematic Studies on Host and Endosymbiont of a Green Dinoflagellate

进一步描述了具有含有叶绿素a和b的内生共生体的绿色甲藻Y-100菌株，并特别强调了宿主细胞的形态。寄主甲藻细胞无甲壳，整体外观呈裸节状。囊膜或角膜囊基本上由外膜和扁平的囊泡组成，膜泡中不发育膜板层。不同寻常的手篮状鳞片覆盖了整个细胞表面，并覆盖了一层粘性物质。这些发现表明该菌为裸甲科的一个新成员，我们将其命名为绿色鳞毛藻。ET sp.11月寄主细胞的超微结构基本上是典型的甲藻。然而，该生物体有1)通常的细胞质突起，可能是花梗的同系物，2)单一的膜结合体，包含紧靠内共生体的膜片，以及3)横向鞭毛周围的电子不透明网络形成附属物。这些特征在其他甲藻中均未发现。利用高效液相色谱法对绿色双鞭毛藻中一种内生菌的主要类胡萝卜素进行了分析。内生共生体含有常见的叶绿素类胡萝卜素，即新黄质、紫黄质、黄质和β-胡萝卜素。除了这些类胡萝卜素外，还检测到了两个未知的峰。其中一个峰与叶黄素的保留时间相同，但吸收光谱与菠菜叶黄素的吸收光谱不同。另一个峰由于吸光度很低而无法鉴定，但似乎与玉米黄质的吸收峰相同。根据这些结果，推测原生植物似乎最有可能成为内生共生菌的监控者。

A further description of the green dinoflagellate, strain Y-100, with a chlorophyll a- and b- containing endosymbiont is given with special emphasis on the morphology of the host cell. The host dinoflagellate cell is unarmored and has a gymnodinioid overall appearance. The theca or amphiesma basically consists of the outer membrane and flattened thecal vesicles in which no thecal plates are developed. Unusual hand basket-shaped scales cover the entire cell surface together with a layer of mucillaginous material. These findings suggest that the organism is a new member of the Gymnodiniaceae (Gymnodiniales) ; We propoes the name Lepidodinium viride gen. et sp. nov. The ultrastructure of the host cell is basically typical of the dinoflagellates. However, the organism has 1) an usual cytoplasmic projection that may be a homologue of the peduncle, 2) a single membrane-bounded body containing membranous sheets, closely situated next to the endosymbiont, and 3) an electron opaque network-forming appendage surrounding the transverse flagellum. None of these features have been found in other dinoflagellates.Major carotenoids of a endosymbiont in a green dionflagellate, Lepidodinium viride have been analyzed using high-performance liquid chromatography (HPLC). The endosymbiont contains the usual chlorophytes carotenoids, that are neoxanthin, violaxanthin, antheraxanthin and beta-carotene. In addition to thses carotenoids, the two unknown peaks were detected. One peak of the tow is situated at the identical retention time to that of lutein, however, the absorption spectra is diffrent from that of lutein obtained from spinach leaves. Another peak cannot be identified becaues it has quite low absorbance, but seems to be identical to that of zeaxanthin. Based on these results, it is speculated that a prasinophyte would seem to be likeliest candidate for a proqenitor of the endosymbiont.