Summary
An electron microscopical study was made of spermatozoa from the epididymal tail of horses, cattle, pigs, sheep, dogs, cats, rabbits, guinea-pigs, and hares. The fine structure of the sperm head, especially the acrosome and the subacrosomal substance, was analyzed.
The very thin sperm heads of bulls, rams, boars, rabbits, hares, and guinea-pigs were generally slightly paddle-shaped as the anterior and anterio-lateral margins were flexed to one side and the intermediate part of the nucleus showed a plane-convex or curved cross section. The nucleus often showed a “waist” under the posterior part of the acrosome, in sagittal sections. The base of the head was generally asymmetrical on a horizontal plane because the implantation fossa was irregular and often displaced sideways. The cap-shaped acrosome was bounded by a typical “unit membrane” with about the same thickness as the plasma membrane. An acrosomal thickening along the curved edge of the nucleus was present in the thin sperm heads but was not distinct in the thicker sperm heads of dogs, stallions and cats. It was most pronounced on the convex (ventral) side of the bent nuclear margin and often contained areas with increased or decreased opacity. In an often roughly semilunar area of the posterior acrosome region, corresponding to the equatorial segment of light microscopy, the acrosome was distinctly thinner and sligthly denser. This arrangement was also found in those species-horses, cats, and very pronounced in guinea-pigs — where no equatorial segment is visible in the light microscope. The subacrosomal space was widened along the edge of the nucleus, especially apically, and generally also along the anterior border of the equatorial segment. An opaque, amorphous subacrosomal substance filled these marginal and equatorial spaces in most species. In hares large blisters in the subacrosomal space were present along the anterior border of the equatorial segment on both sides of the sperm head. A similar but less conspicuous phenomenon was often seen in rabbit spermatozoa, but not in other species. The “postnuclear cap” of light microscopy is probably formed by two components: the basal plate in the implantation fossa and a dense subsurface lamina in the thin layer of cytoplasm covering the remaining nuclear surface behind the acrosome.
The possible relations of the subacrosomal substance to the “perforatorium” of rat spermatozoa and to sub- and periacrosomal structures in some evertebrate spermatozoa was discussed, as well as the role such structures may play in fertilization.
Similar content being viewed by others
References
Afzelius, B. A., and A. Murray: The acrosomal reaction of spermatozoa during fertilization or treatment with egg water. Exp. Cell Res. 12, 325–337 (1957).
Austin, C. R.: Acrosome loss from the rabbit spermatozoon in relation to entry into the egg. J. Reprod. Fertil. 6, 313–314 (1963).
, and M. W. H. Bishop: Some features of the acrosome and perforatorium in mammalian spermatozoa. Proc. roy. Soc. B 149, 234–240 (1958a).
: Role of the rodent acrosome and perforatorium in fertilization. Proc. roy. Soc. B 149, 241–248 (1958b).
Ballowitz, E.: Die innere Zusammensetzung des Spermatozoenkopfes der Säugetiere. Zbl. Physiol. 5, 65–68 (1891).
Bane, A., and L. Nicander: The structure and formation of the perforatorium in mammalian sperm. Int. J. Fertil. 8, 865–866 (1963).
Bedford, J. M.: Fine structure of the sperm head in ejaculate and uterine spermatozoa of the rabbit. J. Reprod. Fertil. 7, 221–228 (1964).
Bishop, M. W. H., and C. R. Austin: Mammalian spermatozoa. Endeavour 16, 137–150 (1957).
, and A. Walton: Spermatogenesis and the structure of mammalian spermatozoa. In: Marshall's Physiology of reproduction, ed. by Parkes, vol. I:2, p. 1–129. Longmans, London 1960.
Blom, E., and A. Birch-Andersen: An “apical body” in the galea capitis of the normal bull sperm. Nature (Lond.) 190, 1127–1128 (1961).
: The ultrastructure of the bull sperm. II. The sperm head. Nord. Vet.-Med. 17, 193–212 (1965).
Burgos, M. H., and D. W. Fawcett: An electron microscope study of spermatid differentiation in the toad, Bufo arenarum Hensel. J. biophys. biochem. Cytol. 2, 223–240 (1956).
Caulfield, J. B.: Effects of varying the vehicle for OsO4 in tissue fixation. J. biophys. biochem. Cytol. 3, 827–830 (1957).
Clermont, Y., and C. P. Leblond: Spermiogenesis of man, monkey, ram and other mammals as shown by the “periodic-acid-Schiff” technique. Amer. J. Anat. 96, 229–253 (1955).
Colwin, L. H., and A. L. Colwin: Role of the gamete membranes in fertilization in Saccoglossus kowalevskii (Enteropneusta). II. Zygote formation by gamete membrane fusion. J. Cell Biol. 19, 501–518 (1963).
, and A. L. Colwin: Changes in the spermatozoon during fertilization in Hydroides hexagonus (Annelida). J. biophys. biochem. Cytol. 10, 231–254 (1961).
Dalton, A. J., and R. F. Zeigel: A simplified method of staining thin sections of biological material with lead hydroxide for electron microscopy. J. biophys. biochem. Cytol. 7, 409–410 (1960).
Dan, J., Y. Ohori, and H. Kushida: Studies on the acrosome. VII. Formation of the acrosomal process in sea urchin spermatozoa. J. Ultrastruct. Res. 11, 508–524 (1964).
Dickman, Z.: The passage of spermatozoa through and into the zona pellucida of the rabbit egg. J. exp. Biol 41, 177–182 (1964).
, and P. J. Dziuk: Sperm penetration of the zona pellucida of the pig egg. J. exp. Biol. 41, 603–608 (1964).
Duijn, C. van: Mensuration of the heads of boar spermatozoa. Mikroskopie 15, 142–156 (1960).
Dzuik, P. J., and Z. Dickman: Sperm penetration through the zona pellucida of the sheep egg. J. exp. Zool. 158, 237–240 (1965).
Fawcett, D. W.: The structure of the mammalian spermatozoon. Int. Rev. Cytol. 7, 195–235 (1958).
: The anatomy of the mammalian spermatozoon with particular reference to the guinea pig. Z. Zellforsch. 67, 279–296 (1965).
, and R. D. Hollenberg: Changes in the acrosome of guinea-pig spermatozoa during passage through the epididymis. Z. Zellforsch. 60, 276–292 (1963).
, and S. Ito: The fine structure of bat spermatozoa. Amer. J. Anat. 116, 567–610 (1965).
Follenius, E.: Particularités de structure des spermatozoïdes de Lampetra planeri. J. Ultrastruct. Res. 13, 459–468 (1965).
Franklin, L. E.: Morphology of gamete membrane fusion and of sperm entry into oocytes of the sea urchin. J. Cell Biol. 25, 81–100 (1965).
Hadek, R.: Submicroscopic changes in the penetrating spermatozoon of the rabbit. J. Ultrastruct. Res. 8, 161–169 (1963a).
: Study on the fine structure of rabbit sperm head. J. Ultrastruct. Res. 9, 110–122 (1963b.)
Hancock, J. L., and D. J. Trevan: The acrosome and post-nuclear cap of bull spermatozoa. J. roy. micr. Soc. 76, 77–83 (1957).
Kojima, Y.: Electron microscopic study of the bull spermatozoon. Jap. J. vet. Res. 10, 72–74 (1962).
Luft, J. H.: Improvements in epoxy resin embedding methods. J. biophys. biochem. Cytol. 9, 409–417 (1961).
Mancini, R. E., A. Alonso, J. Barquet, B. Alvarez, and M. Nemirovsky: Histo-immunological localization of hyaluronidase in the bull testis. J. Reprod. Fertil. 8, 325–330 (1964).
Millonig, G.: Advantages of a phosphate buffer for OsO4 solutions in fixation. J. appl. Phys. 32, 1637 (1961).
Moricard, R.: Des structures de l'acrosome des spermatozoüdes contenus dans l'utérus chez la Lapine. C. R. Soc. Biol. (Paris) 155, 2243–2245 (1961).
Nagano, T.: Observations on the fine structure of the developing spermatid in the domestic chicken. J. Cell Biol. 14, 193–205 (1962).
Nicander, L.: Electron microscopical studies on the development of the sperm head in some mammals. (In press 1966).
, and A. Bane: Fine structure of boar spermatozoa. Z. Zellforsch. 57, 390–405 (1962a).
: New observations on the fine structure of spermatozoa. Internat. J. Fertil. 7, 339–344 (1962b).
Nijima, L., and J. Dan: The acrosome reaction in Mytilus edulis. I. Fine structure of the intact acrosome. J. Cell Biol. 25, 243–248 (1965a).
: The acrosome reaction in Mytilus edulis. II. Stages in the reaction, observed in supernumerary and calcium-treated spermatozoa. J. Cell Biol. 25, 249–259 (1965b).
Piko, L., and A. Tyler: Fine structural studies of sperm penetration in the rat. Vth Int. Congr. Animal Reprod. Trento. 2, 372–377 (1964).
Retzius, G.: Die Spermien der Nagetiere. Biol. Untersuch., N. F. 14, 133–162 (1909a).
: Die Spermien der Huftiere. Biol. Untersuch., N. F. 14, 163–178 (1909b).
: Die Spermien der Carnivoren. Biol. Untersuch., N. F. 14, 185–198 (1909c).
Saacke, R. G., and J. O. Almquist: Ultrastructure of bovine spermatozoa. I. The head of normal, ejaculated sperm. Amer. J. Anat. 115, 143–161 (1964).
Sabatini, D. B., K. Bensch, and R. J. Barrnett: Cytochemistry and electron microscopy. The preservation of cellular ultrastructure and enzymatic activity by aldehyde fixation. J. Cell Biol. 17, 19–58 (1963).
Srivastava, P. N., C. E. Adams, and E. F. Hartree: Enzymatic action of acrosomal preparations on the rabbit ovum in vitro. J. Reprod. Fertil. 10, 61–67 (1965).
Szollosi, D. G., and H. Ris: Observation on sperm penetration in the rat. J. biophys. biochem. Cytol. 10, 275–283 (1961).
Takashima, R., and Y. Takashima: Electron microscope studies on the fine structure of Nereis spermatozoa before and after the acrosomal reaction. Tokushima J. exp. Med. 10, 117–123 (1963).
Watson, M. L.: Staining of tissue sections for electron microscopy with heavy metals. J. biophys. biochem. Cytol. 4, 475–478 (1958).
Yamane, J.: Über das Vorkommen von zwei eigentümlichen Körperchen als konstante Gebilde im Kopfe der Säugetierspermien. Jap. J. Zool. 1, 109–118 (1925).
Author information
Authors and Affiliations
Additional information
Financial support for this study was received from the State Medical Research Council.
Rights and permissions
About this article
Cite this article
Nicander, L., Bane, A. Fine structure of the sperm head in some mammals, with particular reference to the acrosome and the subacrosomal substance. Zeitschrift für Zellforschung 72, 496–515 (1966). https://doi.org/10.1007/BF00319255
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00319255