Ovary Differentiation and Activity in Teleostei Fish

Teleostei fishes constitute a very large group among the vertebrates. They present several reproductive strategies, and many species are gonochoristics. During the gonadal differentiation, the gonadal primordium undergoes morphological changes giving rise to male or female gonads. Considering the lack of information about gonadal morphogenesis in Teleostei, especially in tangent aspects concerning the establishment of the germinal epithelium and its relation with the formation of the ovarian cavity, Tanichthys albonubes, Corydoras schwartzi, and Amatitlania nigrofasciata were taken as biological models to establish a comparative analysis of the female gonadal differentiation. In undifferentiated gonad, the epithelial cells associate with primordial germ cells and form germline cysts. These are distributed throughout the gonadal tissue; after the entrance of the oogonia into meiosis, the folliculogenesis occurs forming the first follicles, in a quite conserved process. However, the formation of the ovarian cavity is distinct. In T. albonubes and A. nigrofasciata, the lumen is formed by pleating and in C. schwartzi, it is formed by cavitation. The central lumen formed characterizes the cystovarian of Teleostei. Although there are differences in the chronology of the differentiation, the processes involved are quite similar and culminate in the formation of analogous structures

Action of the Metalloproteinases in Gonadal Remodeling during Sex Reversal in the Sequential Hermaphroditism of the Teleostei Fish Synbranchus marmoratus (Synbranchiformes: Synbranchidae)

Teleostei present great plasticity regarding sex change. During sex reversal, the whole gonadincluding the germinal epithelium undergoes significant changes, remodeling, and neoformation.However, there is no information on the changes that occur within the interstitial compartment.Considering the lack of information, especially on the role played by metalloproteinases (MMPs)in fish gonadal remodeling, the aim of this study was to evaluate the action of MMPs on gonadsof sex reversed females of Synbranchus marmoratus, a fresh water protogynic diandric fish. Gonadswere processed for light microscopy and blood samples were used for the determination of plasmasex steroid levels. During sex reversal, degeneration of the ovaries occurred and were graduallyreplaced by the germinal tissue of the male. The action of the MMPs induces significant changesin the interstitial compartment, allowing the reorganization of germinal epithelium. Leydig cellsalso showed an important role in female to male reversion. The gonadal transition coincides withchanges in circulating sex steroid levels throughout sex reversion. The action of the MMPs, in thegonadal remodeling, especially on the basement membrane, is essential for the establishment of anew functional germinal epithelium.Fil: Mazzoni, Talita Sarah. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Lo Nostro, Fabiana Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Ecotoxicología Acuática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Antoneli, Fernanda. Universidade Estadual de Campinas; BrasilFil: Quagio-Grassiotto, Irani. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Comparative analysis of spermiogenesis and sperm ultrastructure in Callichthyidae (Teleostei: Ostariophysi: Siluriformes)

In Corydoradinae, the presence of spermatids in the lumen of the testicular tubules together with spermatozoa suggests that spermatogenesis is of the semicystic type, whereas in Callichthyinae, sperm production occurs entirely within spermatocysts in the germinal epithelium, characterizing cystic spermatogenesis. Spermiogenesis in Callichthyinae is characterized by an initial lateral development of the flagellum, the presence of nuclear rotation to different degrees, an eccentric or medial formation of a nuclear fossa, formation of a cytoplasmic channel, and presence of centriolar migration, being more similar to type I spermiogenesis. In Corydoradinae, spermiogenesis is characterized by eccentric development of the flagellum, the absence of nuclear rotation, an eccentric nuclear fossa formation, formation of a cytoplasmic channel, and absence of centriolar migration, differing from the types previously described. The process of spermatogenesis and spermiogenesis in Corydoradinae and Callichthyinae revealed unique characters for each of these subfamilies, corroborating the hypotheses that they constitute monophyletic groups. In relation to sperm ultrastructure, the comparative analysis of the callichthyid species shows that the general characteristics found in the spermatozoa were similar, thus, reinforcing the hypothesis that the family is monophyletic.Em Corydoradinae, a presença de espermátides junto com espermatozóides no lúmen dos túbulos testiculares sugere uma espermatogênese do tipo semicística, enquanto que em Callichthyinae a produção do esperma ocorre inteiramente dentro dos espermatocistos no epitélio germinativo, caracterizando a espermatogênese cística. A espermiogênese em Callichthyinae é caracterizada por um desenvolvimento inicial lateral do flagelo, pela presença de rotação nuclear em diferentes graus, formação de uma fossa nuclear excêntrica ou medial, formação de um canal citoplasmático, e presença de migração centriolar, sendo mais similar à espermiogênese do tipo I. Em Corydoradinae, a espermiogênese é caracterizada pelo desenvolvimento excêntrico do flagelo, ausência de rotação nuclear, fossa nuclear excêntrica, formação de um canal citoplasmático, e ausência de migração centriolar, diferindo dos tipos descritos previamente. O processo de espermatogênese e espermiogênese em Corydoradinae e Callichthyinae revelaram caracteres únicos para cada subfamília, corroborando a hipótese de que as mesmas constituem grupos monofiléticos. Em relação à ultraestrutura do esperma, a análise comparativa das espécies de Callichthyidae mostra que as características gerais encontradas nos espermatozóides foram similares, reforçando a hipótese de monofilia da família.33735

Spermiogenesis and spermatozoa ultrastructure in the Serrasalminae (Ostariophysi: Characiformes) with further evidence on the relationships of the piranhas and pacus

A ultraestrutura dos espermatozoides e espermiogênese foram estudadas nas espécies Piaractus mesopotamicus, Mylossoma duriventre, Serrasalmus maculatus e Metynnis mola de Serrasalminae, sendo dois padrões distintos reconhecidos: um comum a Mylossoma, Serrasalmus e Metynnis, e o segundo característico de Piaractus. Este último é mais similar ao observado em Salminus e Brycon. Por outro lado, o espermatozoide dos serrasalmíneos compartilha algumas características com espécies da superfamília Anostomoidea. O significado filogenético destes caracteres é discutido.Spermatozoa and spermiogenesis ultrastructure were studied in the serrasalmine species Piaractus mesopotamicus, Mylossoma duriventre, Serrasalmus maculatus, and Metynnis mola and two distinct patterns may be recognized: the first common to Mylossoma, Serrasalmus and Metynnis, and the other, characteristic of Piaractus. The latter pattern is more similar to the conditions found in Salminus and Brycon. On the other hand, serrasalmine spermatozoa also share characteristics with the spermatozoa of species of the superfamily Anostomoidea. The phylogenetic significance of these characters is discussed

Citodiferenciação ultra-estrutural durante a espermiogenese normal de Ceratitis capitata Weidman (Diptera-Tephritidae)

Orientador: Mary Anne Heidi DolderDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Espermátides em diferentes fases de maturação e espermatozóide de Ceratitis capitata, provenientes dos testículos dos machos ou das espermatecas das fêmeas deste inseto, foram preparados segundo as técnicas usuais em microscopia eletrônica, contrastada positiva e negativamente e observados em microscópio eletrônico de transmissão. Algumas variações técnicas como a estocagem do mateiral sem prévia fixação, por 7 a 15 dias, a ¿10 GRAUS¿, em glutaraldeido a 0,25%; fixação em glutaraldeido a 3% adicionado de 2% de ácido tânico; pós-fixação em mistura de tetróxido de ósmio adicionado de 0,05M de ferricianeto de potássio ou de 0,5% de ácido- tânico; desidratação em etanol 95% contendo 2% de ácido fosfotúngstico (EPTA) sem e com contrastação por uranila e chumbo, também foram empregadas no preparo dos espécimes em estudo. As observações da espermiogênese em C. capitata mostraram que esta, como nos insetos em geral, caracteriza- se pela formação do "Nebenkern" ou complexo mitocondrial, formação do flagelo, alongamento celular, condensação do material nuclear e eliminação do citoplasma. As espermátides em fase inicial de diferenciação apresentam núcleo e cromatina com aspecto similar ao das células soma ticas e grande quantidade de mitocôndrias no citoplasma. ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digitalAbstract: Spermatids in various stages of maturation and spermatozoa of Ceratitis capitata) were obtained from the testis of males and the spermathecae of females. Routinely prepared for transmission electron microscopy) they were positively and negatively stained. A few variations of the basic techniques were also employed, namely: Maintaining spermatozoa w ithout previous fixation in a solution of 0,25% glutaraldehyde for 7 to 14 days, at ¿10 DEGREES¿; fixation in 3% glutaraldehyde to which 2% tannic acid was added; post-fixation in a mixture of 1% osmium tetroxide to which either 0,05M potassium ferricianide or 0,5% tannic acid was added; dehydration in 95%.ethanol) containing 2% phosphotungstic acid (EPTA), with or without staining of the sections. The observations on the spermatogenesis of C. capitata are quite similar to the description of this process for insects in general. It may be defined .by the following steps: .Formation of the "Nebenkern", development of the flagellum, celular elongation, nuclear condensation) and elimination of the excess cytoplasm. Spermatids iniciating their differention have a nucleus and chromatin very similar to somatic cells) as well as a large number of mitochondria dispersed in'the cytoplasm. In the next step) these mitochondria fuse to form the "Nebenkern". ...Note: The complete abstract is available with the full electronic digital thesis or dissertationsMestradoBiologia CelularMestre em Ciências Biológica

Centriole behaviour during meiosis of male germ cells of Dermatobia hominis (Diptera:Cuterebridae)

During the meiotic division of Dermatobia hominis spermatogenesis, the centrioles duplicate only in prophase I, giving rise to short cilia which are exposed on the cellular surface. In metaphase I they are internalized and distributed to the daughter cells. Consequently, the secondary spermatocytes have two centrioles which repeat the cycle of cilia externalization followed by internalization. The spermatids receive only one centriole, which changes into a basal body and originates a flagellum. This centriole behaviour seems to be a general feature in insect male germ cell meiosis

Occurrence of Nuages and Lamellae Anulata during spermatogenesis in Dermatobia hominis (Diptera: Cuterebridae)

Various types of nuages and lamellae anulata can be found during Dermatobia hominis spermatogenesis. In spermatogonia, the nuages occur as granules juxtaposed to the cytoplasmic face of the nuclear envelope or as cytoplasmic granules similar toglycogen granules. In spermatocytes, in addition to the nuages, dense spherical bodies of approximately 1.0 µm in diameter are also observed. In the spermatids the nuages can be of the following types: perinuclear granules, spherical granules with diameters varying in length from 0.5 to 1.0 µm, granules similar to glycogen granules, granules with variable diameters which accumulate at the flagellum base forming the centriole adjunct, or remain in the cytoplasm. Nuages can also be observed in these cellular types as dense masses, without a definite outline and are common to animal germinal cells in general. The lamellae anulata on the other hand, are observed only in spermatocytes I and in early spermatids, being always immersed in electron-dense material of indefinite outline. In spermatids, the lamellae anulata are close to the nuclear envelope suggesting, in spite of opposing opinions, that these cells are envolved in the synthesis and transport of material from the nucleus to the cytoplasm