Ultrastructure of spermatogenesis in the white-lined broad-nosed bat, Platyrrhinus lineatus (Chiroptera: Phyllostomidae)

Spermatogenesis, the remarkable process of morphological and biochemical transformation and cell division of diploid stem cells into haploid elongated spermatozoa, is one of the most complex cell differentiations found in animals. This differentiation process has attracted extensive studies, not only because the process involves many radical changes in the cell shape and biochemistry, but also because the phases and steps of differentiation have provided a better basis for analyzing the seminiferous epithelium cycle. Thus, this study aimed to characterize ultrastructurally the spermatogenesis process in the bat Platyrrhinus lineatus in order to provide a basis for determining the stages of spermatogenesis and to facilitate comparisons of the process between bat species and other vertebrates. Based on ultrastructural characteristics three main types of spermatogonia could be accurately identified: A(d), A(p) and B; the differentiation of spermatids was clearly divided into 12 steps (steps 1-3: Golgi phase, steps 4-5: cap phase, steps 6-9: acrosomal phase and steps 10-12: maturation phase). The ultrastructure of spermatozoa, Leydig cells and Sertoli cells was characterized; and some processes including nucleolar disorganization and the formation of synaptonemal complexes, acrosome and chromatoid body were discussed. Based on our results we may conclude that the spermatogenic process of P. lineatus follows the pattern of mammals with some specificity, as the process of formation of the acrosome and the presence of the perfuratorium. By other side, the simpler ultrastructure of its spermatozoon shows a pattern more closely related to the sperm cells of humans and other primates. (C) 2011 Elsevier Ltd. All rights reserved.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Comparative analysis of the male reproductive accessory glands of bat species from the five Brazilian subfamilies of the family Phyllostomidae (Chiroptera)

This study aimed to morphologically characterize and compare the male reproductive accessory glands (RAGs) of bats belonging to the five Brazilian subfamilies of the family Phyllostomidae (Carollia perspicillata—Carollinae; Desmodus rotundus—Desmodontinae; Glossophaga soricina—Glossophaginae; Phyllostomus discolor—Phyllostominae and Platyrrhinus lineatus—Stenodermatinae). The study demonstrated that the RAGs of phyllostomid bats were comprised of a pair of extra-abdominal bulbourethral glands and an intra-abdominal complex, composed of paraurethral glands and a prostate with two (Desmodontinae and Stenodermatinae) or three (Carollinae, Glossophaginae and Phyllostominae) different regions, with the absence of the seminal vesicles; this pattern possibly evolved from a process of compaction of the prostatic regions from an ancestor with three regions.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Structure, histochemistry and seasonal variations of the male reproductive accessory glands in the Pallas’s mastiff bat, Molossus molossus (Chiroptera: Molossidae)

Due to their wide geographical distribution, bats suffer considerable influence from abiotic factors on their reproductive strategies, detected through behavioural or functional assessment of the gonads and accessory glands. The present study aimed to characterise anatomically and morphologically the reproductive accessory glands (RAGs) of Molossus molossus (Molossidae) and evaluate their seasonal variations. The RAGs were removed, fixed, sectioned after histological processing and submitted to the following stains: haematoxylin-eosin, periodic acid-Schiff (PAS) and Gomori's reticulin. Our data demonstrated that the RAGs of M. molossus are composed of a semi-lobed prostatic complex associated with the urethra and a pair of inguinal bulbourethral glands. Histology and three-dimensional reconstruction of the prostatic complex demonstrated the existence of two regions: ventral and dorsal (named according to the position around the urethra). The two regions had distinctive morphological and histological differences, with the ventral region being the most prominent and the dorsal formed by four lobes. Considering the seasonal evaluation, we can infer that the prostatic complex of M. molossus is active throughout the seasons in Sao Paulo State (Brazil) and, although each of the prostatic regions has inherent characteristics, they synchronise to establish the main reproductive peak in spring (early rainy season).Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Structure, histochemistry, ultrastructure and seasonal variations of the male prostatic complex in the black Myotis bat, Myotis nigricans (Chiroptera: Vespertilionidae)

Chiroptera are one of the most diverse orders of mammals and a unique group within Mammalia that posses a wide geographic distribution and considerable variability in reproductive strategies. The aims of the present study were to characterise the male prostatic complex of the bat Myotis nigricans (Vespertilionidae) and evaluate seasonal variations in the prostatic complex of M. nigricans specifically. Twenty-three sexually mature specimens (four sample groups: winter, spring, summer and autumn) were subjected to macroscopic, microscopic, morphometric and ultrastructural analyses. The reproductive accessory glands of M. nigricans were found to be composed of a multilobed complex associated with the urethra and a pair of inguinal bulbourethral glands. The complex was composed of three bilobed prostatic regions (ventral, dorsolateral and dorsal) with no ampullary gland and seminal vesicles. This pattern of lobulation is very similar to that described for the prostate of rodents; however, it differs from that of other mammals and even other families of bats (e.g. Phyllostomidae and Molossidae). Each prostatic region in M. nigricans has unique and distinctive characteristics, which synchronise to establish the main reproductive peak of the species in summer. The data also indicated an asynchrony in the activity of primary and secondary reproductive organs in the annual reproductive cycle of M. nigricans in SAo Paulo State, Brazil.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Seasonal changes in the prostatic complex of Artibeus planirostris (Chiroptera: Phyllostomidae)

The male reproductive accessory glands are important organs that secrete products that ensure the survival, viability and motility of spermatozoa, not only in the male reproductive tract, but also in the female. Most studies relating to the reproduction of bats do not include these glands, and detailed studies of these glands describing annual variations in the morphology and physiology are scarce. The aim of this study was to evaluate the impact of these variations on morphophysiology of the prostatic complex (PC) of Artibeus planirostris (Chiroptera: Phyllostomidae). Adult males were collected from June 2009 to July 2010, and the PC was subjected to various analyses. We observed that the PC showed marked variations throughout the year. Both PC and testicular weight increased synchronously with an increasing rate of circulating testosterone, from the autumn until summer, demonstrating that both organs are regulated by this hormone. Each region of the PC (ventral and dorsal) was unique and distinct. The ventral region showed the glandular lumen as a predominant component, in contrast to the dorsal introduced epithelium; acid phosphatase activity was observed in the epithelium of all acini in the dorsal region, but only in the stroma of the ventral region, in addition each region responded differently to variations in the environment and circulating testosterone. We concluded that the PC of A. planirostris produces two secretory peaks, which were related to a gradual increase in the rate of circulating testosterone, which stimulates both of the prostate regions to prepare for the two reproductive periods. (C) 2013 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq