The present study was undertaken to elucidate some aspects about the nature of the spermatozoon ultrastructure of Crotallus durissus using cytochemical methods. We also provide for the first time the ultrastructural description of this species spermatozoon. Cytochemical studies of spermatozoa have not been performed so far in the Serpentes, and species spermatozoon may prove helpful to better understand the reproductive biology of this group. Besides the synapomorphies of the Squamata and Serpentes, the C. durissus spermatozoon possess the following: circular acrosome tip; rounded perforatorium tip with a stopper-like basal modification; bilateral stratified laminar structures; central electron-dense structure within the proximal centriole; fibrous sheath extending until the level of the second mitochondrial ring; rounded mitochondria in cross-section, but with variable shape and organization in longitudinal and oblique sections, respectively; linear annulus; developed multilaminar membranes in the nuclear region and the midpiece. The formation of membrane filipin-sterol complexes occur sparsely along the head region, specially around the nucleus; the complexes were also present in the midpiece membrane and scarcely lining the flagellum. The complexes were present in the different layers of the multilaminar membranes. The ethanolphosphotungstic acid (E-PTA) treatment releaved the presence of basic proteins in acrosome vesicle, pericentriolar material, peripheral fibers of the axoneme and fibrous sheath. The tannic acid technique revealed the microtubules of the centrioles and the axoneme; the extracellular tubules encircling the spermatozoa and those spread in the epididymal lumen were also observed. However, the immunocytochemistry assay using antibodies against alphatubulin and beta-tubulin, the primary microtubule monomers, does not support the existence of composition similarity between these tubular structures, since the extracellular tubules were not labeled by the antibodies. The results obtained in this work demonstrate that the utilization of electron microscopic techniques may provide relevant information to the study of ophidian reproductive biology, particularly in analyses concerning spermatozoal ultrastructure.

Tavares-Bastos, L., Cunha, L.D., Colli, G.R. and Báo, S.N. 2007. Ultrastructure of spermatozoa of scolecophidian snakes (Lepidosauria, Squamata). -Acta Zoologica (Stockholm) 88 : [189][190][191][192][193][194][195][196][197] We provide a detailed description of the sperm ultrastructure of three species of scolecophidian snakes, Leptotyphlops koppesi (Leptotyphlopidae), Typhlops reticulatus (Typhlopidae) and Liotyphlops beui (Anomalepididae), and make comparisons with the spermatozoa of Ramphotyphlops waitii (Typhlopidae) (Harding et al. 1995). All the species studied bear synapomorphies of Squamata and Serpentes. Among scolecophidian snakes, we identified eight polymorphic characters. Previous analyses of molecular and somatic morphological data provide equivocal solutions to the relationships among Anomalepididae, Leptotyphlopidae and Typhlopidae. A close relationship between Anomalepididae and Typhlopidae is corroborated by two characters of sperm ultrastructure, presence of an electron-dense structure inside the proximal centriole and rounded mitochondria in transverse sections of T. reticulatus , Li. beui and R. waitii , whereas the absence of the ridge on the acrosome surface of Le. koppesi and T. reticulatus support a closer relationship between Typhlopidae and Leptotyphlopidae. The differences observed in sperm ultrastructure within Typhlopidae suggest the existence of snake intrafamilial polymorphism. The sperm characters of blindsnakes contain significant phylogenetic information and may provide important data for snake phylogenetic reconstructions.

We describe the morphology of the spermatozoa of members of the iguanian lizard families Hoplocercidae and Opluridae for the first time. Their spermatozoa are quite similar and resemble the sperm of other iguanian lizards. Through a re-evaluation of sperm descriptions supplied in the literature we coded continuous and discrete characters through a combination of four methods: gap-weighting, step-matrix gap-weighting, reductive coding and composite coding. Parsimony analyses revealed that different methods produced highly incongruent outcomes. In view of the pros and cons of each method, we defend that the combination between composite coding and step-matrix gap-weighting are the most appropriate for our data. The cladogram derived from this analysis is totally resolved and comparatively well supported. We conclude that although the preferred cladogram was not strongly supported in some instances, sperm characters could be a good predictor of relationships among iguanian groups. We compare our hypothesis with preceding studies and we show that some previous groupings are in accordance with our results. Finally, we discuss the validity of those groupings in the light of methodological reasoning.

The aim of this study was to investigate the effects of estradiol and follicle-stimulating hormone (FSH) on survival and growth of caprine preantral follicles. Pieces of ovarian tissue were cultured for 1 or 7 days in minimum essential medium (MEM) containing estradiol (1, 5, 10, 20 or 40 pg/ml), FSH (50 ng/ml), or a combination of the two hormones. Cultured and noncultured control ovarian tissues were processed for histological and ultrastructural studies. The results showed that after 7 days of culture, the treatments that yielded the highest percentage of normal follicles relative to MEM alone were those that combined FSH with estradiol at 1, 5 or 20 pg/ml. The addition of FSH to 1-day cultures containing 1 pg/ml estradiol or to 7-day cultures with 1 or 5 pg/ml estradiol increased the percentage of normal follicles compared to estradiol alone at the same concentrations. After 7 days of culture, all treatments generated higher percentages of developing follicles as compared to control and MEM alone. The addition of either FSH or 10 pg/ml of estradiol to the culture media or estradiol (1, 5, 10 or 20 pg/ml) and FSH in combination significantly increased follicular diameter as compared with MEM alone following 7 days of culture. Ultrastructural studies confirmed follicular integrity after 7 days of culture in the presence of 1 pg/ml estradiol plus FSH. In conclusion, this study demonstrated that the interaction between estradiol and FSH maintains ultrastructural integrity and stimulates activation and further growth of cultured caprine preantral follicles.

de Sá Mandel, S.M., Cunha, L.D., Brandão, J.C., Colli, G.R. and Báo, S.N. 2009. Ultrastructure of spermatozoa of lizards in the genus Mabuya from Central Brazil. -Acta Zoologica (Stockholm) 90 : 68-74This is the first description of spermatozoal ultrastructure of Mabuya skinks. The spermatozoa of the species studied are filiform, consisting of a head region, a midpiece and a tail. The head is characterized by the following features: a depressed acrosome anteriorly, an acrosome vesicle divided into cortex and medulla, paracrystalline subacrosomal material, a pointed tip perforatorium, a circular perforatorium base plate inside the subacrosomal cone, an epinuclear lucent zone separated from the subacrosomal cone by a membrane, a large nuclear rostrum, and round nuclear shoulders. The midpiece presents a bilateral stratified laminar structure, a distal centriole, peripheral fibres 3 and 8 grossly enlarged, columnar mitochondria with linear cristae, dense body rings and a triangular annulus. Finally, the tail is composed of a principal piece and an end piece. An axoneme and a fibrous sheath characterize the principal piece, and the end piece is formed only by an axoneme, which loses its pattern in the last portion. Comparisons with members of Teiidae revealed differences in the numbers of dense rings. A well-developed epinuclear lucent zone in Mabuya is less prominent among teiids. In the spermatozoa of Mabuya , the first ring of dense bodies is very large, uniquely resembling the condition present in snakes.