Abstract: Sponges are important sources of natural bioactive products. In recent years, studies in this area mainly focused on separation, identification and bioactivity determination of sponge compounds. However, little progress has been made on the structure organization and cell biology of the organisms. In this research, histology method and transmission electronic microscopy were used to study the structure pattern of Axinella sp., and identify cells in their natural form. A purification protocol was used to enrich four types of sponge cells. The enriched cells then went through a series of analyses to determine their densities, microscopic features, cellular contents and culturability. The results showed that Axinella sp. held a leuconoid canal system, with a structure consisted of exopinacoderm, ectosome and choanosome. The major cell types were two kinds of spherulous cell (A and B), archaeocyte and choanocyte. The two types of spherulous cells both have high densities, peculiar fluorescent features as well as characteristic cell inclusions. In archaeocytes and choanocytes, carbonhydrate and lipid were detected. The extracts of these two cells had absorptions in visible light region, which shared similar absorption spectra with carotenoid. Besides the spherulous cell B, the other enriched cell fractions showed culturability. The result also suggested that the spherulous cells might be differentiated from the choanocytes. The research provided a foundation for future studies on cell differentiation, metabolism pathways and cell culture pattern of marine sponges.

Key words: Axinella sp., histology, transmission electronic microscopy, cell enrichment, ultrastructure, cell culture