IMMUNOCYTOCHEMICAL STUDY OF TUBULIN IN THE 9-SPERM-AXONEME OF A MONOGENEAN (PLATYHELMINTHES), PSEUDODACTYLOGYRUS SP(1)

The spermatozoon of the monopisthocotylean monogenean Pseudodactylogyr us sp, (a gill parasite of eels) has a single axoneme showing a 9+'1' pattern, a nucleus and a mitochondrion, but has no cortical microtubul es, This species thus provides a very simple model for the study of tu bulin in the 9+'1' axonemes of the Platyhelminthes, in contrast with d igenean sperm which have a more complex spermatozoon with two such axo nemes and cortical microtubules, Indirect immunofluorescence labelling of tubulin shows that the elongating spermatids, initially lying in a ll directions in the early stages, are arranged as parallel elements i n further stages. The number of spermatids in an isogenic group could also be precisely counted and equals 32, Nuclear labelling with fluore scent dyes shows that the nuclei, first located in the common mass of the spermatids, later elongate and migrate into the growing spermatids , and that the nucleus is located in the central part of the mature sp ermatozoon, with the two extremities devoid of nucleus, Labelling with antibodies directed against acetylated, tyrosinated, and polyglutamyl ated tubulin gave positive results, thus indicating that these post-tr anslational modifications of tubulin are present in the axoneme of spe rmatids and spermatozoa of monopisthocotylean monogeneans.