Taxonomy And Phylogeny Of Eleven Species Of Myxosporeans (Myxozoa: Myxosporea) Based On RDNA, With Descriptions Of The Ultrastructure For Sphaerospora Chinensis

This work covered two mainly sections of researchment: one was focused on the taxonomic and phylogenic relation of ten myxosporean from freshwater and marine based on 28S and the analysis of diversity for Myxobolus ampullicapsulatus from the perspective of comparison of 18S and 28S;the second section refer to the ultrastructure of Sphaerospora chinensis to investigate the feature of structure and development. Both the two aspects of study were in order to make deeply study on different myxosporean by advanced measure.In section I, there were totally eleven species included: Ceratomyxa sp.1, Ceratomyxa sp.2, Ceratomyxa sprenti, Ceratomyxa reniforma, Zschokkella sp., Unicauda pelteobagrus, Myxobolus ampullicapsulatus (5 populations), Henneguya doneci(2 population), Myxidium cuneiforme, Thelohanellus nikolskii, Chloromyxum sp. The results were revealed as follow: total 21 DNA fragments of these species were sequenced. The phylogeny, diversity and taxonomic relationship were deduced; the comparison study between 18S and 28S were done. Through the results, the conclusion could be safely arrived that 28S sequence was a considerable mark with a proper variance range.While in section II, we investigated the fine structural of Sphaerospora chinensis with the help of electron microscope and the result of our study indicates that: Sphaerospora chinensis appeared gill-parasitized and monosporous pansporoblasts. Valve cell originated from valve-forming body—a special tiny structure at the edge of pansporoblast. Two valves of spore had several lines of stripes on the outer surface, but they were different in shape and colour in some extent. When the two valves were mature, they jointed by tight junction. With the development of Sphaerospora chinensis, inner structure were likely to degenerate even disappeared. It was a common phenomenon that the extrusion of polar filament from polar capsule which maybe suggested that the tendency of extrusion were likely due to the way of parasitism─the sticky polar filament contributed to making the spore adhere to the gill filament.