Abstract
The differentiation of the spermatids of Bufo arenarum has been described from a study of electron micrographs of thin sections of testis. The development of the acrosome from the Golgi complex takes place in much the same manner as in mammalian spermatogenesis but no acrosome granule is formed. A perforatorium is described for the first time in this species. It is formed by a convergence of dense filaments that arise between the nuclear membrane and the head cap. During maturation of the spermatid the chromatin undergoes striking physicochemical alterations. Fine chromatin granules uniformly dispersed in the karyoplasm are replaced by larger and larger aggregates and these ultimately coalesce to form a very dense sperm head. Two centrioles of cylindrical form are situated very near the base of the sperm head. The longitudinal fibrils of the tail flagellum take origin from one, and the dense fibrous substance of the undulating membrane is closely related to the other. Phase contrast cinematographic observations on the swimming movements of living toad sperm, when considered in relation to the fine structural components of the tail, suggest that there is a contractile component in the undulating membrane as well as in the axial fibrils. The differences in the structure of mammalian and amphibian sperm tails are discussed in relation to differences in the character of their movements.
Full Text
The Full Text of this article is available as a PDF (2.4 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- AUSTIN C. R., SAPSFORD C. S. The development of the rat spermatid. J R Microsc Soc. 1951;71(4):397–406. doi: 10.1111/j.1365-2818.1951.tb00393.x. [DOI] [PubMed] [Google Scholar]
- BAYLEY S. T. An electron microscope study of nucleic acid. Nature. 1951 Sep 15;168(4272):470–471. doi: 10.1038/168470a0. [DOI] [PubMed] [Google Scholar]
- BURGOS M. H., MANCINI R. E. Ciclo espermatogénico anual del Bufo arenarum Hensel. Rev Soc Argent Biol. 1948 Oct-Dec;24(3):328–336. [PubMed] [Google Scholar]
- CAVAZOS L. F., MELAMPY R. M. A comparative study of periodic acid-reactive carbohydrates in vertebrate testes. Am J Anat. 1954 Nov;95(3):467–495. doi: 10.1002/aja.1000950305. [DOI] [PubMed] [Google Scholar]
- CLERMONT Y., EINBERG E., LEBLOND C. P., WAGNER S. The perforatorium; an extension of the nuclear membrane of the rat spermatozoon. Anat Rec. 1955 Jan;121(1):1–12. doi: 10.1002/ar.1091210102. [DOI] [PubMed] [Google Scholar]
- CLERMONT Y., LEBLOND C. P. Spermiogenesis of man, monkey, ram and other mammals as shown by the periodic acid-Schiff technique. Am J Anat. 1955 Mar;96(2):229–253. doi: 10.1002/aja.1000960203. [DOI] [PubMed] [Google Scholar]
- DALLAM R. D., THOMAS L. E. Chemical studies on mammalian sperm. Biochim Biophys Acta. 1953 May;11(1):79–89. doi: 10.1016/0006-3002(53)90010-9. [DOI] [PubMed] [Google Scholar]
- DAOUST R., CLERMONT Y. Distribution of nucleic acids in germ cells during the cycle of the seminiferous epithelium in the rat. Am J Anat. 1955 Mar;96(2):255–283. doi: 10.1002/aja.1000960204. [DOI] [PubMed] [Google Scholar]
- KAHLER H., LLOYD B. J., Jr The electron microscopy of sodium desoxyribonucleate. Biochim Biophys Acta. 1953 Mar;10(3):355–359. doi: 10.1016/0006-3002(53)90265-0. [DOI] [PubMed] [Google Scholar]
- LEBLOND C. P., CLERMONT Y. Spermiogenesis of rat, mouse, hamster and guinea pig as revealed by the periodic acid-fuchsin sulfurous acid technique. Am J Anat. 1952 Mar;90(2):167–215. doi: 10.1002/aja.1000900202. [DOI] [PubMed] [Google Scholar]
- LEUCHTENBERGER C., SCHRADER F. The chemical nature of the acrosome in the male germ cells. Proc Natl Acad Sci U S A. 1950 Nov;36(11):677–683. doi: 10.1073/pnas.36.11.677. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LIQUIER-MILWARD J. Electron microscopy of thymonucleic acid. Biochim Biophys Acta. 1953 Jan;10(1):5–10. doi: 10.1016/0006-3002(53)90203-0. [DOI] [PubMed] [Google Scholar]
- PALADE G. E. A study of fixation for electron microscopy. J Exp Med. 1952 Mar;95(3):285–298. doi: 10.1084/jem.95.3.285. [DOI] [PMC free article] [PubMed] [Google Scholar]
- PORTER K. R., BLUM J. A study in microtomy for electron microscopy. Anat Rec. 1953 Dec;117(4):685–710. doi: 10.1002/ar.1091170403. [DOI] [PubMed] [Google Scholar]
- WILKINS M. H. F., RANDALL J. T. Crystallinity in sperm heads: molecular structure of nucleoprotein in vivo. Biochim Biophys Acta. 1953 Jan;10(1):192–193. doi: 10.1016/0006-3002(53)90232-7. [DOI] [PubMed] [Google Scholar]