|Budget Amount *help
¥7,200,000 (Direct Cost : ¥7,200,000)
Fiscal Year 1997 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1996 : ¥1,500,000 (Direct Cost : ¥1,500,000)
Fiscal Year 1995 : ¥4,400,000 (Direct Cost : ¥4,400,000)
The main objective of this research project was to elucidate the relation ship of the endocytosymbiosis and species diversity of photosynthetic organism with compound chloroplasts, based on their comparative ultrastructure and molecular phylogeny. At the first of this project, establishing the compound chloroplasts and evolutionary significance of eucaryotic photosynthetic organisms with them were invesitigated following the published information and the results obtained from this project, concernig with their subcellular characteristics. Secondaly, focusing on the chlorarachiophytes which are referred to the evolutionary chimaera with nucleomorphs of the receidure of nuleus of the symbiont, the origins of host and endosymbiont composing of the chlorarachiophyte cell were supposed by molecular phylogentic anayses of 18SrRNA,rbcL and EF-Tu gene homology.
As the result obtained from the comparative cytology of the organisms with compound clororplasts, it can be pointed out that their spec
ies divercity were closely related to the different combination of hosts and symbionts, variable degree controlling genetically new organelles originated from symbiont and host organelles, and different chaces encountered the endocytosymbionses during their evolutionary process.
From the comparison with the photosynthetic pigment compositions, chlorarachiophyte plastids would be derived from prasionophycean algae. However, no phylogenetic evidenses heve never been given. Standing on this viewpoint, three genes mentioned above were established among chlorophyll a+b plants, including chorarachniophytes, ulvophytes, prasinophytes and their related organisms. As a results, chloroplasts of chlorarachniophytes would be originated from organisms related with Bryopsis but not from prasinophytes, which was rather related to plasts of euglenophytes. On the other hand, the origin of the host of chlorarachniophytes as ifferred from 18SrRNA was the related protozoa like to euglyphinids or cercomonads. Less