SPERMATOZOON AND SPERMIOGENESIS IN MESOCOELIUM-MONAS (PLATYHELMINTHES, DIGENEA) - ULTRASTRUCTURE AND EPIFLUORESCENCE MICROSCOPY OF LABELINGOF TUBULIN AND NUCLEUS

Spermiogenesis and the spermatozoon were studied in the digenean Mesoc oelium monas Rudolphi, 1819 (from the toad Bufo sp. in Gabon). An ultr astructural study revealed that spermiogenesis follows the usual patte rn found in digeneans, i.e. proximo-distal fusion of axonemes with a m edian cytoplasmic process followed by elongation. The spermatozoon has two fully incorporated axonemes with the 9 + ''1'' trepaxonematan pat tern. Indirect immunofluorescence localization of tubulin and fluoresc ent labelling of the nucleus were used to obtain additional informatio n on the structure of the spermatozoon. It was thus shown that one of the axonemes is slightly shorter than the other (190 versus 220 mu m) and that the filiform nucleus (65 mu m in length) is located at the di stal extremity of the spermatozoon (220 mu m in length). Various monoc lonal and polyclonal antibodies, specific to alpha, beta, acetylated-a lpha, or general tubulin, were used and produced similar labelling.