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Cimetidine, used as an anti-ulcer and adjuvant treatment in cancer therapy, causes disorders in the male reproductive tract, including steroidogenesis. However, its effect on sperm quality and male fertility has been poorly addressed. Since vitamin B12 has demonstrated to recover spermatogonia number and sperm concentration in cimetidine-treated rats, we evaluated the impact of cimetidine on sperm quality and fertility potential and whether vitamin B12 is able to prevent the harmful effect of this drug on steroidogenesis and sperm parameters. Adult male rats were treated for 52 consecutive days as follows: cimetidine group (100 mg/kg of cimetidine), cimetidine/vitamin B12 group (100 mg/kg of cimetidine + 3 µg vitamin B12), vitamin B12 group (3 µg vitamin B12) and control group (saline). Serum testosterone levels and immunofluorescence associated to western blot for detection of 17ß-HSD6 were performed. Sperm morphology and motility, mitochondrial activity, acrosome integrity, DNA integrity by Comet assay, lipid peroxidation as well as fertility potential were analyzed in all groups. Apoptotic spermatids were also evaluated by caspase-3 immunohistochemistry. In the cimetidine-treated animals, reduced serum testosterone levels, weak 17ß-HSD6 levels and impaired spermiogenesis were observed. Low sperm motility and mitochondrial activity were associated with high percentage of sperm tail abnormalities, and the percentage of spermatozoa with damaged acrosome and DNA fragmentation increased. MDA levels were normal in all groups, indicating that the cimetidine-induced changes are associated to androgenic failure. In conclusion, despite the fertility potential of rats was unaffected by the treatment, the sperm quality was significantly impaired. Therefore, considering a possible sperm-mediated transgenerational inheritance, the long term offspring health needs to be investigated. The administration of vitamin B12 to male rats prevents the androgenic failure and counteracts the damage inflicted by cimetidine upon sperm quality, indicating that this vitamin may be used as a therapeutic agent to maintain the androgenic status and the sperm quality in patients exposed to androgen disrupters.

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Ultrastructural studies of spermiogenesis and sperm morphology have found many characters that are likely to provide clues to the phylogeny of the Platyhelminthes. However, the lack of information on many free-living groups has been a limiting factor. There is a single description of the spermatogenesis and spermatozoa in a Phaenocora species, namely P. anomalocoela, therefore a similar analysis was made in Phaenocora unipunctata to compare the intrageneric variation of sperm ultrastructure and spermatogenesis in the Neotyphloplanida. The comparison of the two Phaenocora species shows that several characters have the potential to be relevant to hypothesize phylogenetic relationships at different taxonomic levels. The presence of superficially incorporated axonemes outside the ring of cortical microtubules in the mature sperm cell, resulting from the fusion of the axonemes with the median cytoplasmic process during spermiogenesis, as well as the presence of a constant number of microtubules in the different regions of the spermatozoon, seem to constitute apomorphies of the genus Phaenocora. Furthermore, the presence of an axonemal spur, the compression of cortical microtubules by the rotation of the basal bodies during spermiogenesis, and the presence of a connection between the nucleus and the plasma membrane in the mature spermatozoon, support previous proposals that these characters are apomorphies of Dalytyphloplanida. The comparison of spermatogenesis and spermatozoa of P. unipunctata and P. anomalocoela demonstrates that studying intrageneric variation can give valuable insights into the significance of many characters proposed for phylogenetic studies of the Rhabdocoela.

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Identification Orphulellini grasshoppers (Acrididae: Gomphocerinae) species has been difficult due to high polymorphism rate. Orphulella Giglio-Tos, 1894 is a genus with widespread geographical distribution and poor descriptions. Orphulella punctata (De Geer, 1773) has an extensive record of occurrence and available information about the phallic complex, however, there is poor data describing other parts of the male reproductive tract. The objective of this study was characterizes the internal organs of the male reproductive system and spermatozoa of O. punctata. Orphulella punctata testes are of Fountain type, each having only four follicles. Spermatozoa into the seminal vesicle are arranged in bundles with c.a. 2320 µm length, with a nucleus 110 µm long. The spermatozoa are covered by a glycocalyx, the nucleus is cylindrical with condensed chromatin and connected to the flagellum by a dense and lamellar centriole adjunct. The axoneme have 9 + 9 + 2 pattern and present two symmetrical mitochondrial derivatives. A fibrous net and two flat membranous cisternae fill the space between the axoneme and mitochondrial derivatives. This is the first description of the reproductive system of a Gomphocerinae representative.

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The genus Zaprionus consists of approximately 60 species of drosophilids that are native to the Afrotropical region. The phylogenetic position of Zaprionus within the Drosophilidae family is still unresolved. In the present study, ultrastructural features of spermatozoa of 6 species of Zaprionus as well as the species Drosophila willistoni and Scaptodrosophila latifasciaeformis were analyzed. The ultrastructure revealed that the species have the same flagellar ultrastructure. Two mitochondrial derivatives, one larger than the other, close to the axoneme were present, primarily in D. willistoni (subgenus Sophophora). Except for Z. davidi and Z. tuberculatus, the analyzed species had paracrystalline material in both mitochondrial derivatives. Moreover, the testes showed 64 spermatozoa per bundle in all of the species. In the cluster analysis, 6 Zaprionus species were grouped closely, but there were some incongruent positions in the cladogram. The results indicated that sperm ultrastructure is an important tool for elucidating the phylogeny and taxonomy of insects.

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This study aimed to detailed description of the characteristics of the different germ cell types found in Astyanax altiparanae during spermatogenesis. In this purpose, testes from 25 adult males specimens of A. altiparanae were sampled and submitted to the usual techniques for light microscopy. Based on nuclear shape, chromatin condensation, nucleoli quantity and cell size were identified four spermatogonial types: type A undifferentiated (Aund.*); type A undifferentiated (Aund.); type A differentiated (Adif.); and type B spermatogonia. Spermatocytes were observed in different phases of meiosis (leptotene/zygotene/pachytene and diplotene), metaphase I and II and secondary spermatocytes, being distinguish mainly by their chromosomal organization inside the nucleus. Were also identified three different types of spermatids, which were named as initial, intermediate and final, which can be differentiated by increase in nuclear condensation and spacing among cells inside the cysts, possibly by flagella arise and reduction in nuclear diameter. Thus, this study contribute to a better understand of spermatogenesis in this and other fish species.

O presente estudo teve como objetivo a descrição detalhada dos diferentes tipos de células germinativas encontradas em Astyanax altiparanae durante a espermatogênese. Deste modo, os testículos de 25 espécimes machos e adultos de A. altiparanae foram coletados e submetidos às técnicas usuais para microscopia de luz. Baseado no formato nuclear, condensação da cromatina, quantidade de nucléolos e tamanho celular foram identificados quatro tipos de espermatogônias: indiferenciadas do tipo A (Aund.*); indiferenciadas do tipo A (Aund.); diferenciadas do tipo A (Adif.); e espermatogônia do tipo B. Os espermatócitos foram observados em diferentes fases da meiose (leptóteno/zigóteno, paquíteno e diplóteno), metáfase I e II e espermatócitos secundários, sendo distinguidos principalmente pela organização dos cromossomos nos núcleos. Também foram identificados três diferentes tipos de espermátides, que foram nomeadas como iniciais, intermediárias e finais, que se diferenciaram pelo aumento da compactação nuclear e espaçamento entre as células no cisto, pelo possível surgimento do flagelo, e pelo diâmetro nuclear. Assim, este estudo contribui para um melhor entendimento da espermatogênese nesta e nas demais espécies de peixes.

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This study aimed to detailed description of the characteristics of the different germ cell types found in Astyanax altiparanae during spermatogenesis. In this purpose, testes from 25 adult males specimens of A. altiparanae were sampled and submitted to the usual techniques for light microscopy. Based on nuclear shape, chromatin condensation, nucleoli quantity and cell size were identified four spermatogonial types: type A undifferentiated (Aund.*); type A undifferentiated (Aund.); type A differentiated (Adif.); and type B spermatogonia. Spermatocytes were observed in different phases of meiosis (leptotene/zygotene/pachytene and diplotene), metaphase I and II and secondary spermatocytes, being distinguish mainly by their chromosomal organization inside the nucleus. Were also identified three different types of spermatids, which were named as initial, intermediate and final, which can be differentiated by increase in nuclear condensation and spacing among cells inside the cysts, possibly by flagella arise and reduction in nuclear diameter. Thus, this study contribute to a better understand of spermatogenesis in this and other fish species.(AU)

O presente estudo teve como objetivo a descrição detalhada dos diferentes tipos de células germinativas encontradas em Astyanax altiparanae durante a espermatogênese. Deste modo, os testículos de 25 espécimes machos e adultos de A. altiparanae foram coletados e submetidos às técnicas usuais para microscopia de luz. Baseado no formato nuclear, condensação da cromatina, quantidade de nucléolos e tamanho celular foram identificados quatro tipos de espermatogônias: indiferenciadas do tipo A (Aund.*); indiferenciadas do tipo A (Aund.); diferenciadas do tipo A (Adif.); e espermatogônia do tipo B. Os espermatócitos foram observados em diferentes fases da meiose (leptóteno/zigóteno, paquíteno e diplóteno), metáfase I e II e espermatócitos secundários, sendo distinguidos principalmente pela organização dos cromossomos nos núcleos. Também foram identificados três diferentes tipos de espermátides, que foram nomeadas como iniciais, intermediárias e finais, que se diferenciaram pelo aumento da compactação nuclear e espaçamento entre as células no cisto, pelo possível surgimento do flagelo, e pelo diâmetro nuclear. Assim, este estudo contribui para um melhor entendimento da espermatogênese nesta e nas demais espécies de peixes.(AU)

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Mammalian semen chromatin comprises DNA, protamine, and, at lower levels, other proteins. This constitution confers intense compaction to the chromatin, helping to protect the DNA and causing the head of the sperm to be very small, facilitating the safe transport of its genetic contents. It is known that changes in the sperm chromatin compaction lead to fertility problems in bulls, justifying studies of this structure. Although there are theoretical models of sperm chromatin because of its high compaction, there is no morphological evidence of such models. The aim of this study was to demonstrate the ultrastructure of bovine sperm chromatin in an attempt to corroborate the theoretical chromatin models existing today. The isolated bull sperm heads had their chromatin partially unpacked by chemical treatment using sodium dodecyl sulfate (SDS) and dithiothreitol (DTT) and were then embedded in Epon resin. Using an ultramicrotome, ultrathin sections were obtained, which were contrasted with uranyl acetate and lead citrate, and then viewed under transmission electron microscopy. The methodology used allowed the visualization of toroidal structures interconnected by a filamentous nuclear matrix, which is entirely consistent with the most current theoretical models.

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The Heteroptera have holocentric chromosomes with kinetic activity restricted to the end of chromosomes. The first meiotic division is reductional for the autosomes and equational for the sexual. Only a few species of this suborder have been analyzed. In this study, we observed the morphologies of the testes of the Heteroptera species Belostoma anurum (Herrich-Schäffer, 1948), Belostoma micantulum (Stal, 1858), Gelastocoris angulatus (Melin, 1929), Gelastocoris flavus flavus (Guérin-Méneville, 1844), Rheumatobates crassifemur crassifemur (Esaki, 1926), Buenoa amnigenus (White, 1879), Buenoa unguis (Truxal, 1953), Martarega brasiliensis (Truxal, 1949), Martarega membranácea (White, 1879), Martarega uruguayensis (Berg, 1883), Rhagovelia tenuipes (Champion, 1898) and Rhagovelia zela (Drake, 1959). We found that the testes of these species can be round, round/spiral, or elongated/spiral. The size of the prophase I cells was found to vary, with the smallest ones being detected in B. micantulum and Rha. zela, the largest in G. f. flavus, and ones of intermediate size in R. c. crassifemur and M. brasiliensis. With respect to the chromosome complement, we verified the presence of 2n = 16: (14A+XY, B. micantulum and G. angulatus), 21: (20A+X0, R. c. crassifemur), 23: (22A+X0, Rha. zela and Rha. tenuipes), 25: (24A+X0, Bu. amnigenus and Bu. unguis; 22A+2m+X0, M. membranacea), 27: (24A+2m+X0, M. brasiliensis and M. uruguayensis), 29: (26A+X1X2Y, B. anurum), and 35: (30A+X1X2X3X4Y, G. f. flavus). We found that the features of spermatogenesis in these species are similar to those of other previously described Heteroptera species, differing only in testicular morphology, chromosome number, and sex chromosome system.

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The spiny lobster Panulirus homarus, distributed along the Southeast and Southwest coasts of India, is an important commercial species having mariculture potential. Despite its importance, the structural and ultrastructure features of male gonads from this species have received scarce attention. Hence this study was aimed to describe the male reproductive tract of the species, using standard histological and electron microscopy techniques. Gonads from 94 specimens of P. homarus ranging in carapace length 37mm-92mm from vizhinjam (Southwest coast of India.) were obtained and processed for the study (Histology-70 numbers & ultrastructure-24 numbers). The male reproductive system consists of paired testis and vas deferens located in the cephalothoracic region. Macroscopically, the reproductive tract was observed in lobsters >35mm carapace length. In immature testis, spermatogonia were seen which measured 6.9-13.8µm in diameter and in the mature testis primary (5.4-5.9µm) and secondary spermatocytes (2.8-3µm) and spermatids (2.2-2.4µm) were present. Each vas deferens consists of proximal and distal portions. The spermatophoric mass begins formation in the proximal vas deferens. In the distal vas deferens the spermatophoric mass containing the spermatozoa are arranged in packets towards the periphery by the gelatinous matrix produced by the typhlosole. Ultrastructurally, the spermatogonia have lamina, nucleus and mitochondria like bodies, the primary spermatocytes have nucleus, dense chromatin and vacuolated cytoplasm and the spermatids have mitochondria, endoplasmic reticulum and centrioles. The endoplasmic reticulum and the nuclear envelope in the spermatids form the acrosome. The radial arms with microtubules are formed in association with the dense endoplasmic reticulum, near the nucleus. The sperm has a spherical structure with the nucleus, lamellar region, spikes and acrosome. This is the first comprehensive report of the structure of the male gametes and spermatogenesis in P. homarus from Indian waters.Rev. Biol. Trop. 62 (2): 533-541. Epub 2014 June 01.

La langosta espinosa Panulirus homarus, distribuida a lo largo de las costas sudeste y sudoeste de la India, es una especie de importancia comercial con gran potencial para la mari-cultura. A pesar de su importancia, las características estructurales y ultraestructurales de las gónadas masculinas de esta especie han sido poco estudiadas. Debido a esto, el objetivo de este estudio fue describir el aparato reproductor masculino de dicha especie, utilizando técnicas convencionales de microscopía histológica y electrónica. Se procesaron 94 ejemplares de P. homarus de vizhinjam (costa suroeste de la India) (70 individuos para histología y 24 para ultraestructura), cuyos caparazones variaron de 37 mm a 92 mm de longitud. El sistema reproductor masculino de esta especie consistió en un par de testículos y un conducto deferente situados en la región céfalo-torácica. Macroscópicamente, el aparato reproductor se observó en langostas con una longitud de caparazón >35mm. En testículos inmaduros, la espermatogonia midió 6.9-13.8μm de diámetro y se encontró presente en los testículos maduros primarios (5.4-5.9μm), espermatocitos secundarios (2.8 a 3 μm) y espermátidas (2.2-2.4μm). Cada conducto deferente consistió de porciones proximales y distales. La formación de la masa espermatofórica comienza en los conductos deferentes proximales. En el conducto deferente distal espermatofórico, la masa que contiene los espermatozoides está dispuesta en paquetes hacia la periferia, en una matriz gelatinosa producida por el tiflosol. Ultraestructuralmente, las espermatogonias presentan una lámina, núcleo y mitocondrias, los espermatocitos primarios tienen núcleo, cromatina densa y citoplasma vacuolado, mientras que las espermátidas tienen mitocondrias, retículo endoplasmático y centríolos. En las espermátidas, el retículo endoplásmico y la envoltura nuclear forman el acrosoma. Los brazos radiales con microtúbulos se forman en asociación con el retículo endoplásmico denso, cerca del núcleo. El esperma presenta una estructura esférica con el núcleo, la región laminar, las espinas y el acrosoma. Este documento constituye el primer informe exhaustivo de la estructura de los gametos masculinos y espermatogénesis en P. homarus de la India.

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Studies have shown that the annual reproductive cycle of Eptesicus furinalis includes at least one period of total testicular regression. Thus, this study aimed to evaluate their reproductive cycle ultrastructurally. The annual reproductive cycle was divided into four periods: active, regressing, regressed and recrudescence. The active period was similar to that of other bats, including the completion of spermatogenesis with three main types of spermatogonia (Ad, Ap and B) and 12 steps in the process of spermatid differentiation. However, its spermatozoa differed in that outer dense fibers 1, 5, 6 and 9 are larger than the others and due to the presence of what is likely a probably genera-specific bulging in the anterior portion. In the regressing period, Sertoli cell nuclei migrate to the basal compartment with the nuclei close to the basal lamina. The basal compartment had a more compact appearance than the adluminal compartment, with relaxed cellular connections. In the regressed period, spermatogenesis ceased; the seminiferous epithelium was composed only of Sertoli cells and three types of spermatogonia: types Ad, 1 and 2. In the recrudescence period, spermatogenesis restarted, with the process of reactivation divided into three phases: early, medial and late recrudescence. In conclusion, our study described the process of spermatogenesis and the ultrastructure of the spermatozoa and confirmed the presence of a process of total testicular regression in the annual cycle of E. furinalis. We characterize distinct morphologic variations in the ultrastructure of the testicular cells during the four different periods of the annual reproductive cycle.

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Current knowledge on avian spermiogenesis, including strengths and weaknesses, has been reviewed. Information on avian spermiogenesis considerably lags behind that in mammals because of the paucity of reports in birds. Spermiogenesis in passerine birds has received even much less attention than in non-passerine birds. Mechanisms underlying morphogenesis of the acrosome and nucleus, and roles of microtubular assemblies are poorly understood. The proximal centriole found in non-passerine birds, but hitherto considered to be absent in passerine birds, has recently been described in spermatids and mature spermatozoa of 2 passeridan species, including the Masked weaver for which new and detailed spermiogenetic information is provided in this review. A great deal more studies on spermiogenesis, and spermatogenesis generally, in various avian species are required to considerably enhance knowledge of this phenomenon, contribute to comparative spermatology, provide a basis for appropriate applied studies, and contribute to understanding of phylogeny in this vast order of vertebrates.

RESUMO

Among species of the Chiroptera, spermatogenesis and the fully differentiated spermatozoa differ in morphological and ultrastructural detail. This study therefore aimed to ultrastructurally characterize the spermatogenesis and the spermatozoa of Carollia perspicillata (Phyllostomidae) and compare the process with other species of bats and mammals. The differentiation of spermatogonia is similar to other bats and to Primates, with three main spermatogonia types: Ad, Ap, and B. Meiotic divisions proceed similarly to those of most mammals and spermiogenesis is clearly divided into 12 steps, in the middle of the range of developmental steps for bats (9-16 steps). The process of acrosome formation is similar to that found in Platyrrhinus lineatus, with the acrosome formed by two different types of proacrosomal vesicles. The ultrastructure of the spermatozoon is similar to other bats already described and resembles the typical mammalian sperm model; however, its morphology differs from other mammals such as marsupials and rodents, on account of a simpler spermatozoon head morphology, which indicates a pattern that is more closely related to the sperm cells of humans and other primates. Our data demonstrated that spermatogenesis in C. perspicillata presents great ultrastructural similarities to P. lineatus. This pattern is not surprising, because both species belong to the same family (Phyllostomidae); however, it is observed that C. perspicillata presents some characteristics that are more closely related to phylogenetically distant species, such as Myotis nigricans (Vespertilionidae), which is a fact that deserves attention.

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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 (A(d), A(p), 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.

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The monophyly and phylogenetic relationships among the members of Clade A characids (sensu Malabarba & Weitzman), later redefined and named as the Stevardiinae (sensu Mirande), have been primarily supported by traditional morphological and molecular data. Herein were examined, described and compared spermiogenesis and sperm ultrastructure of 12 species of the genera Boehlkea, Bryconacidnus, Bryconamericus, Creagrutus, Cyanocharax, Hemibrycon, Knodus, Odontostoechus, Piabina, and Rhinobrycon in order to evaluate possible phylogenetic signals and their potential use in recovering relationships of the Stevardiinae. All examined species demonstrated a nuclear rotation equal or less than 95º resulting in a lateral position of the double nuclear fossa and flagellum. In all species, sperm nuclei are slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and lies anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. All species analyzed herein and other species previously examined for these systems in the Stevardiinae share homologous sperm characteristics as evidenced by spermiogenesis, further supporting the monophyly of this clade. Spermatozoa of the Stevardiinae further show three morphotypes (M1, M2, M3) of arrangement of centrioles, flagellum, nucleus and midpiece, hypothesized as successively derived in a series of transformation from the most basal morphotype (M1).(AU)

A monofilia e filogenia dos membros do Clado A (sensu Malabarba & Weitzman), mais tarde redefinido e nomeado Stevardiinae (sensu Mirande), é suportada por dados morfológicos e moleculares. Aqui são examinadas, descritas e comparadas a espermiogênese e ultraestrutura do espermatozoide de 12 espécies dos gêneros Boehlkea, Bryconacidnus, Bryconamericus, Creagrutus, Cyanocharax, Hemibrycon, Knodus, Odontostoechus, Piabina e Rhinobrycon, a fim de avaliar possíveis sinais filogenéticos e seu uso potencial no estudo de relações filogenéticas em Stevardiinae. Em todas as espécies examinadas observa-se uma rotação nuclear igual ou menor que 95º, resultando em uma posição lateral da fossa nuclear dupla e do flagelo. Em todas as espécies o núcleo do espermatozoide é alongado em direção ao flagelo, o centríolo proximal é anterior e oblíquo ao centríolo distal e localiza-se parcialmente inserido na fossa nuclear, e a peça intermediária é pequena e fortemente assimétrica. Todas as espécies de Stevardiinae analisadas aqui e outras analisadas previamente compartilham características homólogas dos espermatozoides evidenciadas por sua espermiogênese, corroborando a monofilia deste clado. Os espermatozoides de Stevardiinae apresentam ainda três morfotipos (M1, M2, M3) de acordo com o arranjo dos centríolos, flagelo e peça intermediária, considerados como sucessivamente derivados em uma série de transformações a partir do morfotipo mais basal (M1).(AU)

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The genus Markiana was until recently recognized as incertae sedis in the family Characidae, even though alternative placements for this genus have been advanced since its original description. More recently, it was hypothesized that Markiana nigripinnis is part of a clade informally named the Astyanax clade, indicating the putative close relationship of Markiana with the genus Astyanax. Examination of sperm ultrastructure of representatives of Astyanax and M. nigripinnis shows no evidence for this hypothesized close relationship. Rather, the spermatozoa of M. nigripinnis share characters found in spermatozoa of the non-inseminating members of the subfamily Stevardiinae, such as an angle of nuclear rotation equal to 85º resulting in a lateral position of the double nuclear fossa and flagellum. As with the non-inseminating Stevardiinae, sperm nuclei are also slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. Additionally, M. nigripinnis shares with the other members of the Stevardiinae the presence of only four teeth in the inner row of the premaxillary and a short triangular ectopterygoid, which is never more than twice the length of the palatine.(AU)

O gênero Markiana até recentemente foi reconhecido como incertae sedis na família Characidae, apesar da localização alternativa para este gênero desde sua descrição original. Mais recentemente, surgiu a hipótese de que Markiana nigripinnis faz parte de um clado chamado informalmente de "Astyanax clade", indicando a suposta relação de Markiana com o gênero Astyanax. A análise da ultraestrutura dos espermatozoides de representantes do gênero Astyanax e M. nigripinnis não mostra nenhuma evidência de estreita relação. Pelo contrário, os espermatozóides de M. nigripinnis compartilham o padrão encontrado nos espermatozoides dos membros não-inseminadores da subfamília Stevardiinae, tais como, um ângulo de rotação nuclear igual a 85º resultando em uma posição de lateral da fossa dupla nuclear e do flagelo. Assim como nos Stevardiinae não inseminadores, os núcleos dos espermatozoides também são ligeiramente alongados em direção ao flagelo, o centríolo proximal é anterior e oblíquo em relação ao centríolo distal e parcialmente inserido na fossa nuclear, e a peça intermediária é curta e fortemente assimétrica. Além disso, M. nigripinnis compartilha com os outros membros da Stevardiinae a presença de apenas quatro dentes na série interna da pré-maxila e um osso ectopterigoide curto e triangular, que nunca ultrapassa o dobro do comprimento do osso palatino.(AU)

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The monophyly and phylogenetic relationships among the members of Clade A characids (sensu Malabarba & Weitzman), later redefined and named as the Stevardiinae (sensu Mirande), have been primarily supported by traditional morphological and molecular data. Herein were examined, described and compared spermiogenesis and sperm ultrastructure of 12 species of the genera Boehlkea, Bryconacidnus, Bryconamericus, Creagrutus, Cyanocharax, Hemibrycon, Knodus, Odontostoechus, Piabina, and Rhinobrycon in order to evaluate possible phylogenetic signals and their potential use in recovering relationships of the Stevardiinae. All examined species demonstrated a nuclear rotation equal or less than 95º resulting in a lateral position of the double nuclear fossa and flagellum. In all species, sperm nuclei are slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and lies anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. All species analyzed herein and other species previously examined for these systems in the Stevardiinae share homologous sperm characteristics as evidenced by spermiogenesis, further supporting the monophyly of this clade. Spermatozoa of the Stevardiinae further show three morphotypes (M1, M2, M3) of arrangement of centrioles, flagellum, nucleus and midpiece, hypothesized as successively derived in a series of transformation from the most basal morphotype (M1).

A monofilia e filogenia dos membros do Clado A (sensu Malabarba & Weitzman), mais tarde redefinido e nomeado Stevardiinae (sensu Mirande), é suportada por dados morfológicos e moleculares. Aqui são examinadas, descritas e comparadas a espermiogênese e ultraestrutura do espermatozoide de 12 espécies dos gêneros Boehlkea, Bryconacidnus, Bryconamericus, Creagrutus, Cyanocharax, Hemibrycon, Knodus, Odontostoechus, Piabina e Rhinobrycon, a fim de avaliar possíveis sinais filogenéticos e seu uso potencial no estudo de relações filogenéticas em Stevardiinae. Em todas as espécies examinadas observa-se uma rotação nuclear igual ou menor que 95º, resultando em uma posição lateral da fossa nuclear dupla e do flagelo. Em todas as espécies o núcleo do espermatozoide é alongado em direção ao flagelo, o centríolo proximal é anterior e oblíquo ao centríolo distal e localiza-se parcialmente inserido na fossa nuclear, e a peça intermediária é pequena e fortemente assimétrica. Todas as espécies de Stevardiinae analisadas aqui e outras analisadas previamente compartilham características homólogas dos espermatozoides evidenciadas por sua espermiogênese, corroborando a monofilia deste clado. Os espermatozoides de Stevardiinae apresentam ainda três morfotipos (M1, M2, M3) de acordo com o arranjo dos centríolos, flagelo e peça intermediária, considerados como sucessivamente derivados em uma série de transformações a partir do morfotipo mais basal (M1).

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RESUMO

The genus Markiana was until recently recognized as incertae sedis in the family Characidae, even though alternative placements for this genus have been advanced since its original description. More recently, it was hypothesized that Markiana nigripinnis is part of a clade informally named the Astyanax clade, indicating the putative close relationship of Markiana with the genus Astyanax. Examination of sperm ultrastructure of representatives of Astyanax and M. nigripinnis shows no evidence for this hypothesized close relationship. Rather, the spermatozoa of M. nigripinnis share characters found in spermatozoa of the non-inseminating members of the subfamily Stevardiinae, such as an angle of nuclear rotation equal to 85º resulting in a lateral position of the double nuclear fossa and flagellum. As with the non-inseminating Stevardiinae, sperm nuclei are also slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. Additionally, M. nigripinnis shares with the other members of the Stevardiinae the presence of only four teeth in the inner row of the premaxillary and a short triangular ectopterygoid, which is never more than twice the length of the palatine.

O gênero Markiana até recentemente foi reconhecido como incertae sedis na família Characidae, apesar da localização alternativa para este gênero desde sua descrição original. Mais recentemente, surgiu a hipótese de que Markiana nigripinnis faz parte de um clado chamado informalmente de "Astyanax clade", indicando a suposta relação de Markiana com o gênero Astyanax. A análise da ultraestrutura dos espermatozoides de representantes do gênero Astyanax e M. nigripinnis não mostra nenhuma evidência de estreita relação. Pelo contrário, os espermatozóides de M. nigripinnis compartilham o padrão encontrado nos espermatozoides dos membros não-inseminadores da subfamília Stevardiinae, tais como, um ângulo de rotação nuclear igual a 85º resultando em uma posição de lateral da fossa dupla nuclear e do flagelo. Assim como nos Stevardiinae não inseminadores, os núcleos dos espermatozoides também são ligeiramente alongados em direção ao flagelo, o centríolo proximal é anterior e oblíquo em relação ao centríolo distal e parcialmente inserido na fossa nuclear, e a peça intermediária é curta e fortemente assimétrica. Além disso, M. nigripinnis compartilha com os outros membros da Stevardiinae a presença de apenas quatro dentes na série interna da pré-maxila e um osso ectopterigoide curto e triangular, que nunca ultrapassa o dobro do comprimento do osso palatino.

Assuntos

RESUMO

Spermatozoon maturation involves an extense and complex process beginning with proliferation and differentiation of spermatogonia, passing through meiosis, and ending with spermiogenesis. The later event involves morphological and biochemical changes in order to transform spermatids into spermatozoa. Ultrastructural aspects of the spermiogenesis and testicular spermatozoa of the anuran Eupemphix nattereri (Steindachner, 1863) were analyzed by transmission electron microscopy. Spermiogenesis involves chromatin condensation and nuclear elongation, with visible cytoplasmic elimination. At this stage, a large amount of microtubules and glycogen can also be seen in Sertoli cell cytoplasm, surrounding each spermatid. The spermatozoon is fusiform and the acrossome forms a cap in the anterior region of the nucleus. A mitochondrial sleeve is found around the proximal portion of the tail. The tail presents an axonema with a 9+2 pattern, a justaxonemal fiber, an undulating membrane, and the absence of axial rod. This organization shows some similarities with species of the genus Physalaemus (Leiuperidae) such as P. biligonigerus (Cope, 1861), P. gracilis (Boulenger, 1883) and P. fuscomaculatus (Steindachner, 1864).

A maturação dos espermatozóides envolve um extenso e complexo processo que começa com a proliferação e diferenciação das espermatogônias, passa pela meiose e finaliza com a espermiogênese. Nessa fase, eventos envolvendo alterações morfológicas e bioquímicas transformam espermátides em espermatozóides. Aspectos ultra-estruturais da espermiogênese e do espermatozóide do anuro Eupemphix nattereri (Steindachner, 1863) foram analisados através de microscopia eletrônica de transmissão. A espermiogênese envolve condensação da cromatina e alongamento nuclear, com visível eliminação de citoplasma. Nesse estágio, grande quantidade de microtúbulos e glicogênio podem ser visualizados no citoplasma das células de Sertoli, rodeando cada espermátide. O espermatozóide é fusiforme e o acrossomo forma uma capa na região anterior do núcleo. A bainha mitocondrial é encontrada ao redor da porção proximal da cauda. A cauda apresenta o axonema com o modelo 9+2, uma fibra axonemal, a membrana ondulante e ausência de bastão axial. Esta organização apresenta algumas similaridades com espécies do gênero Physalaemus (Leiuperidae) como P. biligonigerus (Cope, 1861), P. gracilis (Boulenger, 1883) e P. fuscomaculatus (Steindachner, 1864).

RESUMO

Spermatozoon maturation involves an extense and complex process beginning with proliferation and differentiation of spermatogonia, passing through meiosis, and ending with spermiogenesis. The later event involves morphological and biochemical changes in order to transform spermatids into spermatozoa. Ultrastructural aspects of the spermiogenesis and testicular spermatozoa of the anuran Eupemphix nattereri (Steindachner, 1863) were analyzed by transmission electron microscopy. Spermiogenesis involves chromatin condensation and nuclear elongation, with visible cytoplasmic elimination. At this stage, a large amount of microtubules and glycogen can also be seen in Sertoli cell cytoplasm, surrounding each spermatid. The spermatozoon is fusiform and the acrossome forms a cap in the anterior region of the nucleus. A mitochondrial sleeve is found around the proximal portion of the tail. The tail presents an axonema with a 9+2 pattern, a justaxonemal fiber, an undulating membrane, and the absence of axial rod. This organization shows some similarities with species of the genus Physalaemus (Leiuperidae) such as P. biligonigerus (Cope, 1861), P. gracilis (Boulenger, 1883) and P. fuscomaculatus (Steindachner, 1864).

A maturação dos espermatozóides envolve um extenso e complexo processo que começa com a proliferação e diferenciação das espermatogônias, passa pela meiose e finaliza com a espermiogênese. Nessa fase, eventos envolvendo alterações morfológicas e bioquímicas transformam espermátides em espermatozóides. Aspectos ultra-estruturais da espermiogênese e do espermatozóide do anuro Eupemphix nattereri (Steindachner, 1863) foram analisados através de microscopia eletrônica de transmissão. A espermiogênese envolve condensação da cromatina e alongamento nuclear, com visível eliminação de citoplasma. Nesse estágio, grande quantidade de microtúbulos e glicogênio podem ser visualizados no citoplasma das células de Sertoli, rodeando cada espermátide. O espermatozóide é fusiforme e o acrossomo forma uma capa na região anterior do núcleo. A bainha mitocondrial é encontrada ao redor da porção proximal da cauda. A cauda apresenta o axonema com o modelo 9+2, uma fibra axonemal, a membrana ondulante e ausência de bastão axial. Esta organização apresenta algumas similaridades com espécies do gênero Physalaemus (Leiuperidae) como P. biligonigerus (Cope, 1861), P. gracilis (Boulenger, 1883) e P. fuscomaculatus (Steindachner, 1864).

RESUMO

The objective of this study was to describe some changes in spermatids differentiating events during spermiogenesis, leading to spermatozoa final formation. The animals were sacrificed with ethylic acid inhalation and, then, testis fragments were collected, fixed in Karnovsky and post-fixed in osmium tetroxide. After dehydration, the sections were stained with uranyl acetate 2%. It was observed in early spermatids at Golgi phase, formation of acrosomal granule contained in the acrosomal vesicle, spheroidal nucleus with rugous reticulum around it, and Golgi apparatus made up of lamellae and vesicular structures. At cephalic hood phase, the granule suffers flattening and the marginal fossa is formed. In both phases, it was possible to observe the presence of multivesicular body. At acrosomal phase, the acrosomal system is set up, and several enzymes of endoplasmatic reticulum as well chromatoid body are observed in the cytoplasm. At the last phase, that is, maturation, the nucleus becomes more elongated, the endoplasmatic reticulum regresses, the Golgi apparatus approaches to the flagellum and mitochondrias align next to it.

El objetivo del estudio, fue describir algunas alteraciones producidas en la espermiogénesis, en los eventos que diferencian a las espermátidas y que llevan a la formación final de los espermatozoides. Los ratones fueron sacrificados con inhalación de éter etílico y, enseguida, se recolectaron fragmentos de testículos, los que fueron fijados en Karnovsky y tetróxido de osmio. Después de la deshidratación, los cortes fueron teñidos con acetato de uranilo al 2 %. En espermátidas jóvenes en la fase de Golgi se observan: formación del gránulo acrosómico contenido en la vesícula acrosómica, núcleo esferoidal con retículo rugoso a su alrededor, y aparato de Golgi formado por lamelas y estructuras vesiculares. En la fase de capuz cefálico, el gránulo sufre achatamiento y se forma la fosa marginal. En estas dos fases fue posible observar la presencia del cuerpo multivesicular. En la fase acrosómica se establece el sistema acrosómico, distingiéndose en el citoplasma muchas vesículas de retículo endoplasmático y cuerpo cromatoide. En la última fase, la de maduración, el núcleo se torna más alargado, el retículo endoplasmático retrae, el aparato de Golgi se aproxima al flagelo y las mitocondrias se alinean a lo largo de él.

Assuntos