ISSN : 1225-3480
The ultrastructural characteristics of germ cells during spermatogenesis and mature sperm morphology in male Pinctada martensii were investigated by transmission electron microscope observation. The morphologies of the sperm nucleus and the acrosome of this species are the oval shape and cone shape, respectively. Spermatozoa are approximately 47-50 μm in length including a sperm nucleus (about 1.24 μm in length), an acrosome (about 0.60 μm in length), and tail flagellum (about 45-47μm). The axoneme of the sperm tail shows a 9+2 structure. In P. martensii in Pteriidae, a special substructure showing a thick and wide triangular shape which is composed of electron-dense opaque material (occupied about 50% of all, the upper part of the acrosomal vesicle), appeared in the upper region (part) of the acrosomal vesicle, while the lower region (part) of the acrosomal vesicle is composed of electron-lucent material. Thus, this special structure, which exist in the upper part of the acrosomal vesicle in P. martensii, is somewhat different from those of other subacrosomal vesicle in other families in subacrosomal vesicles. Therefore, we assume that the existence of a special substructure showing a thick and wide triangular shape in the acrosomal vesicle of the spermatozoon can be used as a key characteristic for identification of P. martensii or other species in Pteriidae in subclass Pteriomorphia. The number of mitochondria in the midpiece of the sperm of this species are five (exceptionally sometimes four), as one of common characteristics appear the same number of mitochondria in the same families of superfamilyies. This species in Pteriidae does not contain the axial rod and satellite fibres which appear in the species in Ostreidae in subclass Pteriomorphia. These characteristics can be used for the taxonomic analysis of the family or superfamily levels as a systematic key or tools.
Baccetti, B, and Afzelius, B. A. (1976) Biology of sperm cell. S. Krager, New York p. 1-254 (Monogr Devel Biol No. 10).
Baccetti, B. (1979) The evolution of the acrosomal complex. In: Fawcett DW., Bedford JM (eds.) The spermatozoon. Urban Schwarzenberg, Baltimore p. 305-328.
Bernard, R. T. F, and Hodgson. AN (1985) The fine structure of the sperm and spermatid differentiation in the brown mussel Pernaperna. South Africa Journal of Zoology, 20:5-9.
Chung, E. Y. and Ryou, D. K. (2000) Gametogenesis and sexual maturation of the surf clam, Mactra veneriformis on the west coast of Korea. Malacologia, 42: 149-163.
Chung, E. Y., Chung, C. H., Kim, J. H., Park, S. W. and Park, K. H. (2010) Ultrastructuresof germ cells and the accessory cells during spermatogenesis in male Gomphina veneriformis (Bivalvia: Veneridae) on the east coast of Korea. Korean Journal of Malacology, 26: 51-62.
Chung, E. Y.,, Kim, E. J. and Park, G.M. (2007) Spermatogenesis and sexual maturation in male Mactra chinensis (Bivalvia: Mactridae) of Korea. Integrative Bioscience, 11: 227-234.
Dorange G. and Le Pennec M. (1989) Ultrastructural characteristics of spermatogenesis in Pecten maximus (Mollusca, Bivalvia). Invertebrate Reproduction & Development, 15: 109-117.
Eckelbarger K. J, Bieler R. and Mikkelsen P. M. (1990) ltrastructure of sperm development and mature sperm morphology in three species of commensal bivalves (Mollusca: Galeommatoidea). Journal of Morphology, 205: 63-75.
Eckelbarger K. J. and Davis C. V. (1996) Ultrastructure of the gonad and gametogenesis in the eastern oyster, Crassostrea virginica. II. Testis and spermatogenesis. Marine Biology, 127: 89-96.
Franzén Å. (1970) Phylogenetic aspects of the mophology spermatozoa and spermiogenesis in Baccetti B (ed): "Comparative spermatology". Accademia Nationale Dei Lincei, Rome 573pp.
Franzén, Å. (1983) Ultrastructural studies of spermatozoa in three bivalve species with notes on evolution of elongated sperm nucleus in primitive spermatozoa. Gamete Research 7: 199-214.
Franzen, A. 1956. On spermiogenesis. Morphology of the spermatozoon and biology of fertilization among invertebrates. Zool. Bidr. Upps,. 31: 255-482.
Galangau, M. V. 1969. Etude en microscopie eletronique de la gametodenese de Milax gagates (Draparnaud, 1801) (Gasteropodes, Pulmones, Limacidae). Evolution des ultrastructures au cours de la spermatodenese chez dirrerents types de mollusques, These Doct. Etat. Montepellier, P. 151.
Gaulejac, de J., Jenry, M. and Vicente N (1995) An ultrastructural study of gametogenesis of the marine bivalve Pinna nobilis (Linnaeus, 1758). II. Spermatogenesis. Journal of Molluscan Study, 61: 393-403.
Healy, J. M. (1989) Spermiogenesis and spermatozoa in the relict bivalve genus Neotrigonia: relevance to trigonioid relationships, particularly Unionoidea. Marine Biology, 103: 75-85.
Healy, J. M. (1995) Sperm ultrastructure in in the marine bivalve families Carditidae and Crassatellidae and its bearing on unification of the Crasssatelloidea with the Carditoidea. Zoological Science, 24: 21-28.
Hodgson, A. N. and Bernard, R. T. F. (1986) Ultrastructure of the sperm and spermatogenesis of three species of Mytilidae (Mollusca, Bivalvia). Gamete Research, 15: 123-135.
Jamieson, B. G. M. (1991) Fish evolution and systematics: evidence from spermatozoa. Cambridge University Press, Cambridge. pp.181-194.
Kim, J. .H., Chung, E. Y., Choi, K. H, Lee, K. Y, and Choi, M. S. (2010a) Ultrastructure of the testis and germ cell development during spermatogenesis in male Crassostrea gigas (Bivalvia: Ostreidae) in western Korea. Korean Journal Malacology, 26: 235-244.
Kim, J. H. (2001) Spermatogenesis and comparative ultrastructure of spermatozoa in several species of Korean economic bivalves (13 families, 34 species). Ph.D. thesis, Pukyung National University 161pp.
Kim, J. H. and Kim, S. H. 2011. Spermiogenesis and Taxonomic Value of Sperm Morphologies of Two Species in Veneridae (Bivalvia: Heterodonta). Korean J. Marlacol. 27(2): 149-157.
Kim, J. H., Chung E. Y, Choi K. H, Park K. H, Park S. W. (2010b Ultrastructure of germ cells during spermatogenesis and some characteristics of sperm morphology in male Mytilus coruscus (Bivalvia: Mitilidae) on the west coast of Korea. Korean Journal of Malacology, 26: 33-43.
Kwon, O. K., Park G. M. and Lee, J. S. (2003) Coloured shells of Korea. Academy Pubshing Co. Seoul, 288pp.
Longo, F. J. and Anderson, E. (1969) Spermatogenesis in the surf clam Spisular solidissima with special reference to the formation of the acrosomal vesicle. Journal of Ultrastructure Research, 27: 435-443.
Longo, F. J. and Dornfeld, E. J. (1967) The fine structure of spermatid differentiation in the mussel Mytilus edulis. J. Ultrastruct. Res., 20: 462-480.
Min, D. K. Lee, J. S., Ko, D. B. and Je, J. G. (2004) Mollusks in Korea. Hanguel Graphics, Busan, Korea 566pp.
Popham J. D. (1979) Comparative spermatozoon morphology and bivalve phylogeny. Malacological Review, 12: 1-20.
Popham, J. D. (1974) Comparative morphometrics of the acrosomes of the sperms of externally and internally fertilizing sperms of the sperms of the shipworms (Teredinidae, Bivalvia, Mollusca). Cell Tissue Research, 150: 291-297.
Sousa, M., Corral, L. and Azevedo, C. (1989) Ultrastructural and cytochemical study of spermatogenesis in Scrobicula riaplana (Mollusca, Bivalvia). Gamete Research, 24: 393-401.