Análise ultraestrutural e imunocitoquímica da espermatogênese e nucleologênese de morcegos
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Data
2012-02-24
Autores
Beguelini, Mateus Rodrigues [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Embora o processo de reprodução tenha sido objeto de estudo em muitos mamíferos, relativamente pouca atenção tem sido dada a esse estudo em morcegos, apesar dessa ser uma grande e diversa classe de organismos, que apresenta diferentes estratégias reprodutivas para ajustar esses animais às várias condições ecológicas e comportamentais as quais estão submetidos. Da mesma forma, em geral todas as observações sobre o ciclo nucleolar foram feitas a partir da análise de células mitóticas. Assim, o intuito do presente estudo foi analisar características reprodutivas e do ciclo nucleolar meiótico de espécies de morcegos Neotropicais. No epitélio seminífero, três tipos de espermatogônias foram reconhecidos: Ad, Ap e B. Essas após entrarem em meiose, passam por duas divisões celulares e formam espermátides haplóides, que sofrem diferenciação, compactando seu DNA, alongando seu núcleo e formando o flagelo e acrossomo, num processo que, em microscopia eletrônica de transmissão, pode ser dividido em doze fases. Observamos que o processo de espermiogênese ocorre de forma semelhante em Platyrrhinus lineatus, Molossus molossus e Myotis nigricans e que os espermatozóides de P. lineatus e M. molossus apresentam semelhanças, como o formato mais alongado da cabeça, a presença do perforatorium e espessamentos nas fibras densas externas 1, 5 e 6. Por outro lado, M. nigricans apresenta a ausência de perforatorium e espessamentos nas fibras axilares 1, 5, 6 e 9. Comparando os padrões reprodutivos de Artibeus planirostris e M. nigricans, observamos que, apesar de ambos serem espécies Neotropicais, eles diferem acentuadamente em sua reprodução. Artibeus planirostris apresenta um perfil de espermatogênese ativo durante todo o ano, possivelmente apresentando um padrão poliéstrico...
Although the process of reproduction has been studied in many mammals, relatively little attention has been given to this study in bats, this large and diverse order of organisms, which presents different reproductive strategies to adjust the animals to various environmental conditions and behaviors that they are inserted. Likewise, in general all studies on the nucleolar cycle were made based on the analysis of mitotic cells. Thus, the purpose of this study was to analyze the reproductive characteristics and the nucleolar meiotic cycle of Neotropical bat species. In the seminiferous epithelium, three types of spermatogonia were recognized: Ad, Ap and B. These, after enter in meiosis, undergo two cell divisions to form haploid spermatids, which undergo differentiation, compressing their DNA, stretching its nucleus and forming the acrosome and flagellum, a process that, in transmission electron microscopy, can be divided into twelve stages. We note that the process of spermiogenesis occured similarly in Platyrrhinus lineatus, Molossus molossus and Myotis nigricans and that the spermatozoon of P. lineatus and M. molossus have similarities, as the more elongated shape of the head, the presence of perforatorium and thickening in the outer dense fibers 1, 5 and 6. On the other hand, M. nigricans did not present the perforatorium and the thickening was presented in the fibers 1, 5, 6 and 9. Comparing the reproductive patterns of Artibeus planirostris and M. nigricans, we observed that, although both are Neotropical species, they differ markedly in their reproduction. Artibeus planirostris presents an active pattern of spermatogenesis throughout the year, possibly exhibiting a polyestral bimodal pattern, with two pronounced peaks of spermatogenic production, one in September and another in February. On the other... (Complete abstract click electronic access below)
Although the process of reproduction has been studied in many mammals, relatively little attention has been given to this study in bats, this large and diverse order of organisms, which presents different reproductive strategies to adjust the animals to various environmental conditions and behaviors that they are inserted. Likewise, in general all studies on the nucleolar cycle were made based on the analysis of mitotic cells. Thus, the purpose of this study was to analyze the reproductive characteristics and the nucleolar meiotic cycle of Neotropical bat species. In the seminiferous epithelium, three types of spermatogonia were recognized: Ad, Ap and B. These, after enter in meiosis, undergo two cell divisions to form haploid spermatids, which undergo differentiation, compressing their DNA, stretching its nucleus and forming the acrosome and flagellum, a process that, in transmission electron microscopy, can be divided into twelve stages. We note that the process of spermiogenesis occured similarly in Platyrrhinus lineatus, Molossus molossus and Myotis nigricans and that the spermatozoon of P. lineatus and M. molossus have similarities, as the more elongated shape of the head, the presence of perforatorium and thickening in the outer dense fibers 1, 5 and 6. On the other hand, M. nigricans did not present the perforatorium and the thickening was presented in the fibers 1, 5, 6 and 9. Comparing the reproductive patterns of Artibeus planirostris and M. nigricans, we observed that, although both are Neotropical species, they differ markedly in their reproduction. Artibeus planirostris presents an active pattern of spermatogenesis throughout the year, possibly exhibiting a polyestral bimodal pattern, with two pronounced peaks of spermatogenic production, one in September and another in February. On the other... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Morcego - Reprodução, Espermatogenese em animais, Nucleosintese, Ciclo celular, Meiose, Spermatogenesis, Nucleologenesis
Como citar
BEGUELINI, Mateus Rodrigues. Análise ultraestrutural e imunocitoquímica da espermatogênese e nucleologênese de morcegos. 2012. 222 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Biociências, Letras e Ciências Exatas, 2012.