Ultrastructure and ontogeny of eyespots in dinoflagellates : an approach from the perspective of their endosymbiotic origins.

从太平洋沿岸的不同地方采集了许多甲藻，包括柱头和散光物种，随后建立了克隆培养。其中一种为蜜腺类甲藻的一新属和一种，定名为Amphidiniella sedentaria HOriguchi gen.et sp.nov.此外，还描述了一种新的具有新型眼斑的甲藻--裸甲藻，并对其超微结构和个体发育进行了详细的研究。本研究发现4种甲藻中含有一种色生内生藻类，这些发现使这类甲藻的总数达到6种。这六种甲藻具有相似的内共生菌类型和相同类型的眼点(B型眼点)，这是在整个甲藻中仅在这六种物种中发现的。对这些种的纹枯病的超微结构进行了研究。虽然这6个物种在形态上有很大的差异，但基于上述共同特征，这6个物种被认为是单性的。由于对甲藻中眼斑的个体发育知之甚少，因此对B型眼斑的个体发育进行了较高的显微镜研究。结果表明，该复制过程是眼斑划分和从头形成的混合过程。B型眼点中是否存在细胞器DNA尚未得到证实。

Many dinoflagellates, both stigmatic and astigmatic species, were collected from various localities along the Pacific coast and subsequently clonal cultures were established. One of them was found to be a new genus and a species of honyaulacoid dinoflagellates and was described as Amphidiniella sedentaria Horiguchi gen.et sp.nov. Furthermore, a new dinoflagellate, Gymnodinium natalense Horiguchi et Pienaar sp.nov.which possesses a novel type of eyespot was slso described and its ultrastructure and ontogeny of the eyespot was studied in detail.Four species of dinoflagellates were found to contain a chromophyte endosymbiotic alga in this study and these findings made the total number of such dinoflagellates six. These six species share the characteristics, such as similar type of endosymbiont and same type of eyespot (Type B eyespot) which has been found only in these six species among entire dinoflagellates. The ultrastructure of the eyespot of these species was studied. Although these six species are morphologically quite defferent, based on above mentioned shared characteristics, the monophily of these six species was proposed.Since little has been known regarding the ontogeny of eyespot in dinoflagellates, the ontogeny of Type B eyespot was investigated hight microscopically. It was found that the duplication process was mixture of eyespot devision and de novo formation. The presence of organella-DNA in the Type B eyespot was not confirmed.