Skip to main content
PMC home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1968 Oct 1;39(1):119–134. doi: 10.1083/jcb.39.1.119

ZYGOTE FORMATION IN ASCARIS LUMBRICOIDES (NEMATODA)

W Eugene Foor 1
PMCID: PMC2107505  PMID: 5678444

Abstract

Ultrastructural observations of the in utero sperm of Ascaris lumbricoides reveal that it consists of a relatively clear, ameboid anterior region and a conical posterior region containing numerous surface membrane specializations, dense mitochondria, a lipid-like refringent body of variable size, and a dense nucleus which lacks an apparent nuclear envelope. No acrosomal complex was observed. Pseudopods emanating from the anterior cytoplasm make first contact with the primary oocytes and appear to be responsible for the localized removal of the extraneous coat covering the oolemma. Subsequently the gamete membranes interdigitate and finally fuse. Because this pseudopodial action appears similar to that reported for the acrosomal filaments in flagellated sperm, the anterior region of the Ascaris sperm is thought to serve an acrosomal function. Following gamete-membrane fusion, the sperm nucleus acquires a particulate appearance and becomes disorganized. Once inside the oocyte, the sperm cytoplasm consists of dense mitochondria, ribosomes, and vesicles derived from the surface membrane specializations. The refringent body, whose contents possibly contribute to the synthesis of ribosomes, is usually absent by the time the sperm cytoplasm attains a central position in the egg.

Full Text

The Full Text of this article is available as a PDF (1.8 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. BURGOS M. H., FAWCETT D. W. Studies on the fine structure of the mammalian testis. I. Differentiation of the spermatids in the cat (Felis domestica). J Biophys Biochem Cytol. 1955 Jul 25;1(4):287–300. doi: 10.1083/jcb.1.4.287. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Clark W. H., Jr, Moretti R. L., Thomson W. W. Electron microscopic evidence for the presence of an acrosomal reaction in Ascaris lumbricoides var. suum. Exp Cell Res. 1967 Sep;47(3):643–647. doi: 10.1016/0014-4827(67)90027-4. [DOI] [PubMed] [Google Scholar]
  3. Foor W. E. Ultrastructural aspects of oocyte development and shell formation in Ascaris lumbricoides. J Parasitol. 1967 Dec;53(6):1245–1261. [PubMed] [Google Scholar]
  4. Jamuar M. P. Studies of spermiogenesis in a nematode, Nippostrongylus brasiliensis. J Cell Biol. 1966 Dec;31(3):381–396. doi: 10.1083/jcb.31.3.381. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Koulish S. Ultrastructure of differentiating oocytes in the trematode Gorgoderina attenuata. I. The "nucleolus-like" cytoplasmic body and some lamellar membrane systems. Dev Biol. 1965 Oct;12(2):248–268. doi: 10.1016/0012-1606(65)90030-8. [DOI] [PubMed] [Google Scholar]
  6. LUFT J. H. Improvements in epoxy resin embedding methods. J Biophys Biochem Cytol. 1961 Feb;9:409–414. doi: 10.1083/jcb.9.2.409. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Lee D. L., Anya A. O. The structure and development of the spermatozoon of Aspiculuris tetraptera (Nematoda). J Cell Sci. 1967 Dec;2(4):537–544. doi: 10.1242/jcs.2.4.537. [DOI] [PubMed] [Google Scholar]
  8. MOSES M. J. Spermiogenesis in the crayfish (Procambarus clarkii) II. Description of stages. J Biophys Biochem Cytol. 1961 Jul;10:301–333. doi: 10.1083/jcb.10.3.301. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. PANIJEL J., PASTEELS J. Analyse cytochimique de certains phénomènes de recharge en ribonucléoproteines; le cas de l'oeuf de Parascaris equorum lors de la fecondation. Arch Biol (Liege) 1951;6(3):353–370. [PubMed] [Google Scholar]
  10. PASTEELS J. Recherches sur le cycle germinal chez l'Ascaris; étude cytochimique des acides nucléiques dans l'oögénèse, la spermatogénès et le développement chez Parascaris equorum Goerze. Arch Biol (Liege) 1948;59(4):405–446. [PubMed] [Google Scholar]
  11. PETHICA B. A. The physical chemistry of cell adhesion. Exp Cell Res. 1961;Suppl 8:123–140. doi: 10.1016/0014-4827(61)90344-5. [DOI] [PubMed] [Google Scholar]
  12. REYNOLDS E. S. The use of lead citrate at high pH as an electron-opaque stain in electron microscopy. J Cell Biol. 1963 Apr;17:208–212. doi: 10.1083/jcb.17.1.208. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. SABATINI D. D., BENSCH K., BARRNETT R. J. Cytochemistry and electron microscopy. The preservation of cellular ultrastructure and enzymatic activity by aldehyde fixation. J Cell Biol. 1963 Apr;17:19–58. doi: 10.1083/jcb.17.1.19. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. SMITH B. V., LACY D. Residual bodies of seminiferous tubules of the rat. Nature. 1959 Jul 25;184:249–251. doi: 10.1038/184249a0. [DOI] [PubMed] [Google Scholar]
  15. SWIFT H. The fine structure of annulate lamellae. J Biophys Biochem Cytol. 1956 Jul 25;2(4 Suppl):415–418. doi: 10.1083/jcb.2.4.415. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Tilney L. G., Porter K. R. Studies on microtubules in Heliozoa. I. The fine structure of Actinosphaerium nucleofilum (Barrett), with particular reference to the axial rod structure. Protoplasma. 1965;60(4):317–344. doi: 10.1007/BF01247886. [DOI] [PubMed] [Google Scholar]
  17. WATSON M. L. Staining of tissue sections for electron microscopy with heavy metals. J Biophys Biochem Cytol. 1958 Jul 25;4(4):475–478. doi: 10.1083/jcb.4.4.475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. YASUZUMI G., KAYE G. I., PAPPAS G. D., YAMAMOTO H., TSUBO I. Nuclear and cytoplasmic differentiation in developing sperm of the crayfish, Cambaroides japonicus. Z Zellforsch Mikrosk Anat. 1961;53:141–158. doi: 10.1007/BF00339438. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES