[Nature and development of the basic proteins during the spermiogenesis in Pleurodeles waltlii Michah., Urodele amphibian]

Acrosome biosynthesis in spermatocytes and spermatids revealed by HPA lectin cytochemistry

The origin of the acrosome is controversial, because of both its lysosomal nature and at the moment of its appearance, which seems to be species-specific. Considering the amazing organization shown by the acrosome of some urodele amphibians, HPA-colloidal gold cytochemistry was used to analyze the biogenesis of the acrosome in the urodele Pleurodeles waltl at electron microscopy level. The results showed that HPA-labeling is useful to label the acrosome and its precursor vesicles and, consequently, HPA-histochemistry could be used as a marker of acrosomal content. Labeling of the Golgi apparatus and precursor vesicles was seen in primary spermatocytes and round (stage I) spermatids, thus contributing solid evidence for the beginning of acrosome biogenesis before meiosis. In both primary spermatocytes and round spermatids, an enigmatic vesicle, probably related to the biosynthesis of the neck piece or the tail, was also labeled. Labeling in elongating spermatids (stage II-IV), showed a homogeneous distribution of colloidal gold particles in the acrosomal cap, but the perforatorium was not positive to the lectin. However, in mature (stage V-VI) spermatids, a regional distribution of labeling in the acrosome was seen, with the apical knob showing a stronger labeling than the lateral barb, and the lateral barb showing a stronger labeling than the principal piece of the acrosomal cap. This regional distribution of the labeling suggests that the acrosome develops several domains with different glycoconjugate compositions.

On the diversity of sperm histones in the vertebrates. I. Changes in basic proteins during spermiogenesis in the newt Notophthalmus viridescens

Sperm histones display great variability in contrast to the conservation of most classes of somatic histones. To study this paradox, this series of papers examines the variation of histone patterns in the testis and sperm of vertebrates, particularly amphibians and reptiles, and attempts to relate such variation to genetically based sex determination as hypothesized by Bloch [Genetics Supplement 61, 93 (1969)]. In the present study we have investigated spermiogenesis in the newt Notophthalmus viridescens viridescens. Cytochemical experiments indicate that the basic nuclear proteins undergo progressive shifts from somatic type histone leads to very arginine-rich "stable protamine" in the later spermatids leads to protamine in the mature sperm. Electrophoresis of Notophthalmus histones extracted from chromatin reveals that the pattern of testes specific basic proteins in the urodele is distinct from the pattern of testicular proteins in the anurans Bufo americanus and Xenopus laevis. Species within the class Amphibia therefore exhibit considerable diversification in their type of basic sperm proteins.

On the diversity of sperm histones in the vertebrates: II. A cytochemical study of the basic protein transitions during spermiogenesis in the cartilaginous fish Hydrolagus colliei

Spermiogenesis in the ratfish (Hydrolagus colliei) is characterized by unusual changes in the basic proteins of the nucleus. Cytochemical analysis indicates that early spermatids in this cartilaginous fish contain the somatic type of histones. However, late spermatids contain the salmon type of sperm histone whereas spermatozoa display the mouse/grasshopper type designated by Bloch ('69). Such an unusual cytochemical shift from protamine in the spermatid to "stable protamine" in the sperm has not been documented heretofore.

The use of glycol methacrylate embedding for studies of chromatin distribution and fine structure in salmon spermatid nuclei

Glycol methacrylate has been used as an embedding medium for studies of spermiogenesis in the salmon. DNA and basic proteins are shown to stain with the same specificity in thick (0.5-1.0 mu) sections of GMA-embedded salmon testes as in sections of comparably fixed, paraffin-embedded testes. Stain can be localized far more precisely in GMA sections than in paraffin sections due to the thinness of the sections and to the excellent structural preservation of nuclei. In addition, ultra-thin sections of GMA-embedded salmon testes can be observed with the electron microscope, and this permits exact correlation between nuclear fine structure and chemical composition in consecutive sections of the same nuclei.

Autoradiographic study of mouse spermatozoan arginine-rich nuclear protein in fertilization

General labeling of ripe mouse spermatozoa was obtained two weeks after six injections of L-arginine-5-3H monohydrochloride, administered within two days. Besides tail labeling a very intensive nuclear labeling was obtained. It is presumed that this nuclear labeling represents almost exclusively tritiated arginine incorporation into basic nuclear protein. Mouse oocytes were fertilized in vitro with such labeled spermatozoa. It was found that the nuclear label is lost very early during male pronucleus formation, probably concomitantly with sperm chromatin decondensation. This might indicate total loss of the basic spermatozoal nuclear protein before male genome activation.