Annual reproductive cycle of males of the flat-faced fruit-eating bat, Artibeus planirostris (Chiroptera: Phyllostomidae)

Artibeus planirostris is an endemic species of Phyllostomid bat from the Neotropical region. Some studies have indicated that it exhibits seasonal bimodal polyestry; however, others postulate that it may be able to produce young at any time during the year. Thus, the aim of this study was to evaluate the annual variations in testicular and epididymal parameters of this species in southeast Brazil and try to understand how the reproduction of this species is regulated in this environment. Sixty mature male specimens, collected between June 2009 and May 2010, were submitted to morphometric and immunohistochemical analysis. Our study showed that A. planirostris presented a continuously active pattern of spermatogenesis throughout the year, presenting spermatozoa inside its cauda epididymis in all months, but with two pronounced peaks of spermatogenic production, one in September and other in February. We propose that the males developed these two peaks in order to produce sufficient sperm for the reproduction in a harem system and to synchronize with the female reproductive cycle, which had a bimodal polyestric pattern. Control of this variation is directly linked to the expression of the androgen receptor (AR) in Sertoli cells and to serum testosterone levels, which appear to synchronize to establish these two peaks. In the months preceding the two peaks, the testis have a higher expression of the AR, which possibly stimulates the increase in PCNA, and drives a gradual increase in the testicular parameters. Taken together the results suggest that if sperm storage happens in this species, it is of short duration. © 2013 Elsevier Inc.

Seasonal effects on semen and testosterone in zebu and taurine bulls

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Potencial reprodutivo de Chrysoperla externa (Neuroptera: Chrysopidae): Efeito da proporção sexual e período de acasalamento

In this study the effects of the time of male permanence with females and different sex ratios on the reproductive capacity of Chrysoperla externa F 3 adults was evaluated. The insects were kept at 25 ± 2 °C, 70 ± 10% RH, under a 12 h photoperiod. The first experiment consisted of mating females with males that were subsequently removed after 5, 10, 15, 20, 25, 30, 35 and 40 days; the control group consisted of males remaining with the females during the entire experimental period. The second experiment consisted of mating: one male with one female (1:1); one male with two females (1:2); one male with three females (1:3); one male with four females (1:4); and one male with five females (1:5), and then evaluating their pre-ovipositioning periods, daily and total ovipositioning, egg viability percentages, and efficiency indices (which considered total ovipositioning, mean egg viability, and the ovipositioning period). It was found that alternating the sexual proportions from one male with one female to one male with three females did not alter the reproductive performance of these insects, and that there was no need to replace the males after five days as they were able to provide sufficient numbers of spermatozoa during this period to maintain consistent reproductive rates.

Light microscope observations on the epididymis of paca (Agouti paca)

The features of paca epididymis, based on its appearance in light microscope, is described in this paper. The cellular population of the epithelial lining comprises principal cells, basal cells, apical cells, narrows cells, and hallo cells. The epididymis is divided in five distinct and continuous regions, Zone I, or initial segment, and zone II, are both localized into the head. Zone III comprises the distal head and all the body. Zones IV and V are restricted to the tail, in the proximal and distal cauda epididymis respectively. Each zone can be readily distinguished on the basis of morphological characteristics. The height of epididymal epithelium is greater in zone I. There is a progressive increase in the diameter of the tubular lumen through the different areas, with the maximum in the zone V. The presence of a high epithelium, and the virtual absence of sperm in zone I suggest fast transit of spermatozoa in this region. Zone V comprises the distal tail, has smaller epithelial lining, greater luminal diameter, shorter stereocilia than the other zones, and contains spermatozoa packed inside the lumen, that characterizes this zone as a place of sperm storage. The findings are compared with other reports in rodents and other domestic animals, to contribute to the understanding of epididymal morphophysiology. © 2013 Firenze University Press.

Effects of Pentoxifylline on Equine Epididymal Sperm

This study evaluated whether pentoxifylline (PTX) present in the flushing extender influenced the function of equine epididymal spermatozoa after recovery and after thawing. For this experiment, 58 testicles from 29 Brazilian Jumping Horses were used. Cauda epididymides of each stallion were separated and flushed with a skim milk extender, with or without 7.18 mM PTX and then subjected to the freezing process. Samples flushed with the extender containing PTX showed a significant increase in total motility, progressive motility, straight line velocity, curvilinear velocity, and percentage of rapid sperm immediately after the recovery of epididymal sperm and after 15 minutes of incubation at 37°C (P < .05). However, the presence of PTX in the flushing extender did not affect the post-thaw motility parameters or plasma membrane integrity (P > .05). The results of this study showed that the PTX present in the flushing extender improved motility parameters of recently recovered epididymal sperm and had no deleterious effects on plasma membrane integrity and freezability of equine epididymal sperm. © 2013 Elsevier Inc. All rights reserved.

An assessment approach for application of spermatic data in phylogenetic analyses: Within the genus Moenkhausia Eigenmann, 1903 (Characiformes: Characidae)

Spermiogenesis and sperm ultrastructure from 21 species of Moenkhausia and others related genera are described. To evaluate the phylogenetic signals, 18 unordered characters were utilized in implied weighting analysis through the program TNT 1.1. Four variations of spermiogenesis were found. In the earliest spermatids, the nucleus can be positioned lateral, eccentric, strongly eccentric or nearly medial in relation to the distal centriole. The nuclear rotation can be present or absent. These spermiogenesis processes are related or intermediate to Type I and Type III. Taking into account the degrees of nuclear rotation during the spermiogenesis and other characteristics, distinct forms of spermatozoa are observed among the species analyzed. The phylogenetic analysis yielded a single most parsimonious tree with fit value 2.70000 and the topology obtained founds Moenkhausia as non-monophyletic. However, some hypothesis of relationships previously proposed viz the clade 20, which contains the type species Moenkhausia xinguensis, is recovered herein. This clade is supported by five synapomorphies, and it allows the supposition that these species constitute a monophyletic group. The whole topology is presented and discussed. © 2012 The Authors. Acta Zoologica © 2012 The Royal Swedish Academy of Sciences.

Cooling of ejaculated and epididymal stallion sperm

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ultrastructural characteristics of the spermatogenesis during the four phases of the annual reproductive cycle of the black myotis bat, Myotis nigricans (Chiroptera: Vespertilionidae)

Myotis nigricans is an endemic species of vespertilionid bat, from the Neotropical region, that resembles temperate zone bats in their reproductive cycle; presenting an annual reproductive cycle with two periods of testicular regression, which are not linked to the apoptotic process and seems to be not directly linked to any seasonal abiotic variation. Thus, this study aimed to ultrastructurally evaluate their reproductive cycle. The process of testicular regression could be divided into four periods: active; regressing; regressed and recrudescence; with all presenting distinct characteristics. The active period was similar to that of other bats, presenting the complete occurrence of spermatogenesis, with three main types of spermatogonia (Ad, Ap, and B) and 12 steps in spermatid differentiation; however, it differed in having the outer dense fibers 1, 5, 6, and 9 larger than the others. These three types of spermatogonia undergo considerable morphologic changes from regressing to the regressed period, and in the recrudescence, they return to the basic morphology, which reactivates spermatogenesis. In conclusion, our study described the process of spermatogenesis, the ultrastructure of the spermatozoa and the distinct morphologic variations in the ultrastructure of the testicular cells of M. nigricans during the four different periods of its annual reproductive cycle. Microsc. Res. Tech., 76:1035-1049, 2013. © 2013 Wiley Periodicals, Inc.

Involvement of pituitary gonadotropins, gonadal steroids and breeding season in sex change of protogynous dusky grouper, Epinephelus marginatus (Teleostei: Serranidae), induced by a non-steroidal aromatase inhibitor

Two experiments were performed using the aromatase inhibitor (AI) letrozole (100mg/kg) to promote sex change, from female-to-male, in protogynous dusky grouper. One experiment was performed during the breeding season (spring) and the other at the end of the breeding season (summer). During the spring, AI promoted sex change after 9weeks and the sperm produced was able to fertilize grouper oocytes. During the summer, the sex change was incomplete; intersex individuals were present and sperm was not released by any of the animals. Sex changed gonads had a lamellar architecture; cysts of spermatocytes and spermatozoa in the lumen of the germinal compartment. In the spring, after 4weeks, 11ketotestosterone (11KT) levels were higher in the AI than in control fish, and after 9weeks, coincident with semen release, testosterone levels increased in the AI group, while 11KT returned to the initial levels. Estradiol (E2) levels remained unchanged during the experimental period. Instead of decreasing throughout the period, as in control group, 17 α-OH progesterone levels did not change in the AI-treated fish, resulting in higher values after 9weeks when compared with control fish. fshβ and lhβ gene expression in the AI animals were lower compared with control fish after 9weeks. The use of AI was effective to obtain functional males during the breeding season. The increase in androgens, modulated by gonadotropins, triggered the sex change, enabling the development of male germ cells, whereas a decrease in E2 levels was not required to change sex in dusky grouper. © 2013 Elsevier Inc.

Sperm motility parameters for Steindachneridion parahybae based on open-source software

Summary: The objective of this work was to evaluate the sperm motility of 13 Steindachneridion parahybae males using open-source software (ImageJ/CASA plugin). The sperm activation procedure and image capture were initiated after semen collection. Four experimental phases were defined from the videos captured of each male as follows: (i) standardization of a dialogue box generated by the CASA plugin within ImageJ; (ii) frame numbers used to perform the analysis; (iii) post-activation motility between 10 and 20 s with analysis at each 1 s; and (iv) post-activation motility between 10 and 50 s with analysis at each 10 s. The settings used in the CASA dialogue box were satisfactory, and the results were consistent. These analyses should be performed using 50 frames immediately after sperm activation because spermatozoa quickly lose their vigor. At 10 s post-activation, 89.1% motile sperm was observed with 107.2 μm s-1 curvilinear velocity, 83.6 μm s-1 average path velocity, 77.1 μm s-1 straight line velocity; 91.6% were of straightness and 77.1% of wobble. The CASA plugin within ImageJ can be applied in sperm analysis of the study species by using the established settings. © 2013 Blackwell Verlag GmbH.

Evolução do processo de espermiação em machos de Piau, Leporinus macrocephalus, hormonalmente induzidos à reprodução

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ciclo reprodutivo da tabarana, Salminus hilarii (Valenciennes, 1849) (Characidae, Salmininae) na região do baixo rio Sorocaba, SP

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biologia reprodutiva de três espécies de serpentes da Família Viperiade da região neotropical

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito do hormônio 17β-estradiol na gametogênese dos órgãos de Bidder e testículos e no tecido hepático em machos de Rhinella schneideri (Anura: Bufonidae)

Pós-graduação em Biologia Animal - IBILCE

Ação dos ésteres do ácido ricinoléico do óleo de mamona nas glândulas salivares e nos ovários de carrapatos Rhipicephalus sanguineus (Latreille, 1806) (Acari : Ixodidae). Análise histológica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)