Cytological studies of the relationship between endocytosymbiosis and arrangement and configuration of organelles in algal cells with special emphasis on the evolutionary significance.

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On the process of evolutionary endosymbiosis, configuration and structure of organelles in the host cell have been turburated by the invation of symbionts. After that, these organelles together with symbiont's ones were rearranged for a novel cell under the genetical and physiological regulation of the host cell. In particular, subcellular diversity found in higher taxa can be considered to be caused by these tuburance and rearrangement of organelles in each cell which was established by endocytosymbiosis. It is not so difficult to assume that these phenomina commonly give rise among phylogenetically different taxa.Using unicellular red algae belonging to the Porphyridiales, Rhodophyta, their subcellular diversity were examined on the focus of their organelles such as chloroplast-pyrenoid and nucleus stained by fluoresent dye under conforcal laser microscope and fluorescent microscopes.As a result, we can distinguished a seies of configurational clain or stepwise morphologies on their … More organellar sturucutres as followings ; 1) photosynthetic organelles increasing their volum and expanding thier surface and a nucleus located not in the center of a cell, 2) embedded pyrenoids changing into naked ones, and chloroplast body showing tendency from central part of cell to the periphery, 3) pyrenoid and nucleus showing the tendency frm cell periphery to the central part of cell, 4) they sometimes compete to occupy the central part of cell with each other, however, nucleus finally occupy the central part of cell, 5) the pyrenoid pushed away from the central part of cell disappearing and chloroplast located cell periphery changing its number in a cell from single to multiple. These results supprted the systematics based on their ultrastructure, habitat, types of the asexual reproduction and composition of phytosynthetic pigments published by Hara and Chihara (1992). In contrast, they could not support the molecular phylogenetic relationship examined by Hara, Yokoyama and Kim (2000) based on their 18SrDNA and psbA Less