Ultrastructure of the Testis and Germ Cell Development During Spermatogenesis in Male Crassostrea gigas (Bivalvia: Ostreidae) in Western Korea

  • Kim, Jin-Hee (Korea Ocean & Fisheries Institute) ;
  • Chung, Ee-Yung (Korea Marine Environment & Ecosystem Institute, Dive Korea) ;
  • Choi, Ki-Ho (West Sea Fisheries Research Institute, National Fisheries Research and Development Institute) ;
  • Lee, Ki-Young (Department of Marine Biotechnology, Kunsan National University) ;
  • Choi, Moon-Sul (Department of Marine Biotechnology, Kunsan National University)
  • Received : 2010.08.10
  • Accepted : 2010.09.10
  • Published : 2010.09.30

Abstract

Ultrastructural characteristics of the testis and spermatogenesis of Crassostrea gigas were investigated by Transmission and Scanning Electron microscope observations. The testis is a diffuse organ consisting of branching acini containing differentiating germ cells in a variety of stages. The acinus is surrounded by an intermitent layer of myoepithelial cells andis divided into subcompartments that are partially separated by pleomorphic accessory cells which remain in close contact with germ cells until late stages of development. these accessory cells contain a large quantity of glycogen particles and lipid droplets in the cytoplasm. Therefore, it is assumed that they are involved in the supplying of the nutrients for germ cell development, while any phenomena associated with phagocytosis of undischarged, residual sperms by lysosomes could be find in the cytoplasm of the accessory cells. The morphology of the spermatozoon has a primitive type and is similar to those of other bivalves. Mature spermatozoa consist of broad, cap-shaped acrosomal vesicle, subacrosomal material (containing axial rod embedded in a granular matrix), a oval nucleus showing deeply invaginated anteriorly, two triplet substructure centrioles surrounded by four spherical mitochondria, and satelite fibres appear to the distal centriole and plasma membrane. Spermatozoa of C. gigas resemble to those of other investigated ostreids. In particular, the anterior region of the acrosomal vesicle is transversely banded. It is assumed that differences in this acrosomal substructure are associated with the inability of fertilization between the genus Crassostrea and other genus species in Ostreidae. Therefore, we can use sperm morphology in the resolution of taxonomic relationships within the Ostreidea. The spermatozoon is approximately $42-47{\mu}m$ in length including an oval sperm nucleus (about $0.91{\mu}m$ in length), an acrosome (about $0.42{\mu}m$ in length) and tail flagellum ($40-45{\mu}m$). The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9 + 2 structure. These morphological charateristics of acrosomal vesicle belong to the family Ostreidae in the subclass Pteriomorphia.

Keywords

References

  1. Chung, E.Y., Lee, T.Y. and An, C.M. (1991) Sexual maturation of the venus clam, Cyclina sinensis, on the west coast of Korea. Journal of Medical and Applied Malacology, 3: 125-136.
  2. Chung, E.Y., Kim, Y.M. and Lee, S.G. (1999) Ultrastructural study of germ cell development and reproductive cycle of the purplish Washington clam, Saxidomus purpuratus (Sowerby). Yellow Sea, 5: 51-58.
  3. Chung, E.Y., Park, K.Y. and Son, P.W. (2005) Ultrastructural study on spermatogenesis and sexual maturation of the mail jicon scallop, Chlamys farreri on the west coast of Korea. Korean Journal of Malacology, 21: 95-105.
  4. Daniels, E.W., Longwell, A.C., McNiff, J.M. and Wolfgang, R.W. (1971) A re-investigation of the ultrastructure of the spermatozoa from the american oyster Crassostrea virginica. Transection American Microscope Society, 90: 275-282. https://doi.org/10.2307/3225187
  5. Dorange, G. and M. Le Pennec. (1989) Ultrastructural characteristics of spermatogenesis in Pecten maximus (Mollusca, Bivalvia). Invertebrate Reproduction & Development, 15: 109-117. https://doi.org/10.1080/07924259.1989.9672031
  6. Drozdov, T.A. and Reunov, A.A. (1986) Spermatogenesis and the sperm ultrastructure in the mussel Modiolus difficillis. Tsitologiia, 28: 1069-1074.
  7. 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. https://doi.org/10.1002/jmor.1052050107
  8. 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. https://doi.org/10.1007/BF00993648
  9. Galtsoff, F.S. and Phillpott, D.E. (1960) ultrastructure of the spermatozoon of the oyster, Crassostrea virginica. Journal of Ultrastructural Research, 3: 241-253. https://doi.org/10.1016/S0022-5320(60)80012-3
  10. 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. https://doi.org/10.1093/mollus/61.3.393
  11. Healy, J.M. (1983) Ultrastructure of euspermatozoa of cerithiacean gastropods (Prosobranchia: Mesogastropoda). Journal of Morphology, 178: 57-75. https://doi.org/10.1002/jmor.1051780105
  12. Healy, J.M. (1988) Sperm morphology and its systematic importanc in the Gastropoda. In: Ponder W.F. (ed) Prosobranch phylogeny. Malacological Review, 4: 251-266.
  13. Healy, J.M. (1989) Spermiogenesis and spermatozoa in the relict bivalve genus Neotrigonia: relevance to trigonioid relationships, particularly Unionoidea. Marine Biology, 103: 75-85. https://doi.org/10.1007/BF00391066
  14. Healy, J.M. and Lester, R.J.G. (1991) Sperm ultrastructure in the Australian oyster Saccostrea commercialis (Iredale & Roughey) (Bivalvia: Ostreoidea). Journal of Molluscan Studies, 57: 219-224. https://doi.org/10.1093/mollus/57.2.219
  15. Healy, J.M. (1995) Sperm ultrastructure in the marine bivalve families Carditidae and Crassatellidae and and its bearing on unification of the Crasssatelloidea with the Carditoidea. Zoological Science, 24: 21-28. https://doi.org/10.1111/j.1463-6409.1995.tb00472.x
  16. Healy, J.M. (1996) Molluscan sperm ultrastructure: correlation with taxonomic units within the Gastropoda, Cephalopoda and Bivalvia. In: Taylor J (ed) Origin and evolutionary radiation of the Mollusca. Oxford University Press, London p. 99-113.
  17. 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. https://doi.org/10.1002/mrd.1120150204
  18. Jamieson B.G.M. (1987) The ultrastructure and phylogeny of insect spermatozoa. Cambridge University Press, Cambridge.
  19. Jamieson B.G.M. (1991) Fish evolution and systematics: evidence from spermatozoa. Cambridge University Press, Cambridge. pp. 181-194.
  20. 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 161 pp.
  21. Lee, J.Y. and Park, J.J. and Chang, Y.J. (1999) Gonadal development and reproductive cycle of Gomphina melanaegis (Bivalvia: Veneridae). Journal of Fisheries Society, 32: 198-203.
  22. 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.
  23. Popham, J.D. (1979) Comparative spermatozoon morphology and bivalve phylogeny. Malacological Review, 12: 1-20.
  24. Sousa, M. and Oliveria, E (1994) An ultrastructural study of Crassostrea angulata (Mollusca, Bivalvia) spermatogenesis. Marine Biology, 120: 41-47.