Effect Of Centrin During The Spermtid Motile Apparatuses Studies In The Fern Ceratopteris Thalictroides

Centrin, a component of the centrosome protein with calcium ions combining ability, belongs to the highly conservative EF- hand protein superfamily. Centrin is concerned to cell differentiation, growth orientation, cilia’s cutting off, the production of sperm tails, centrosome replication and maintaining its structure. Centrin or its homologous gene has been cloned from many eukaryotes(algae, yeast, higher plants and mammals). In the ferns, the spermatogenesis is a process of de novo formation of the motile apparatuses. In Marsilea, centrin expresses at the microspore in advance, and takes part in formation of the motile apparatuses of the spermatid. Howerver, the ways of spermatogenesis in the homosporous ferns is fully different from Marsilea. The ways that the centrin participate the formation of the motile apparatuses maybe different. Therefore, this study uses the model species of the ferns, Ceratopteris thalictroides as the experimental material to clarify the characeristics of space-time expression of centrin and analyse the function and effect of centrin during the spermtid motile apparatuses.The major contents and results of this study are as follows:1. The TEM observation shows that spermatogenesis of Ceratopteris thalictroides undergoes de novo formation of blepharoplast, multilayered sttuture, microtubular ribbon, flagella and the stage of nuclear shaping. The amorphous opaque flocculent material were observed in present study. The structure maybe the nascent blepharoplast. Based on the immunofluorescence observation and series sections, the study support that blepharoplast generates only once in the spermatocyte stage.2. The radial mictutubules are abundant around the blepharoplast at the early development stage, and at this time a notch appears on the nucleus at the site facing the blepharoplast. During the development of blepharoplast, it differentiate centrioles, multilayered structure, microtubular ribbon and basal bodies.They are all microtubular organization of different forms. It shows that blepharoplast have the function as the microtubular organizing center.3. The observation of immunofluorescence of centrin and tubulin shows that centrin only is located in the blepharoplast, multilayered sturture, microbutular ribbon and basal bodies. From the stage of blepharoplast to the stage of basal bodies express strong fluorescence, but at the following stages of nuclear shaping, flagellas and spermatozoids, the centrin fluorescence decrease gradually, and almost disappear at the stage of spermatozoid; The fluorescence labelling showed that the tubulin almost appears at the same time with the centrin. The tubulin were labelled on all the motile apparatuses and express obvious fluorescence. What’s more, there are some fluorescence signal of tubulin in the spermatid nuclear. Based on the space-time expression of the Centrin and Tubulin, it was indicated that the centrin maybe the organizer of spermatid motile apparatuses and have the function on the mircotubular polymerization.In this study, the process of de novo formation of the motile apparatuses of spermatids in Ceratopteris thalictroides was observed by TEM. The space-time immunofluorescence location of centrin and tubulin was studied to explore the function of centrin during the spermatid motile apparatuses. The study lays a foundation for elucidating the molecular mechanism of spermatogenesis in ferns.