Navegando por Assunto "Hypophthalmus marginatus"

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Acesso aberto (Open Access)
Caracterização estrutural e ultraestrutural das células do epitélio gonadal de Hypophthalmus Marginatus (Valenciennes 1840) durante a espermatogênese
(Universidade Federal do Pará, 2014-09-05) GONÇALVES, Liziane Amaral Barbosa; ROCHA, Rossineide Martins da; http://lattes.cnpq.br/4371300451793081
Hypophthalmus marginatus is a siluriforme, belonging to the family Pimelodidae. This species is highly consumed in eastern Amazonia and has a wide socio-economic importance to the region. Studies on the histological characterization of the reproductive system are still unknown in this species. Therefore, this study serves as a tool for biotechnology techniques, necessary for the production in captivity, since this species is one of the fishing resource most intensively exploited by artisanal fisheries. The aim of this study was to characterize the structural and ultrastructural features of germinal epithelium cells of Hypophthalmus marginatus during spermatogenesis. 168 specimens were collected from December 2011 to December 2012. Macroscopically were identified 69 adult males. In field, ventral incision was held in fishes and fragments of testicles from the median region and semen were removed. Then the material was subjected to processing and analysis of light microscopy, transmission electron microscopy and scanning. The data revealed that the germ cells proliferate inside the spermatic cyst synchronously. Spermatids enter at the spermiogenesis process through three distinct stages of cell differentiation. The nucleus does not move relative to the axis flagellar and the centrioles don't migrate to the nucleus. The spermatozoids showed a spherical head with the highly condensed nucleus and no acrosome. The intermediary piece was short containing a single long flagellum. The axoneme presents the structure of microtubules within the pattern (9 + 2). The nuclear fossa housed the proximal centriole partially. The presence of spermatogenic cells in the same subphase of meiosis inside the cyst is characterized as cystic spermatogenesis, with synchronous growth of the cells. This suggests that spermiogenesis of H. marginatus is of type III and the presence of nuclear fossa is considered a distinctive feature for the species, which differs from other pimelodids.
Acesso aberto (Open Access)
Infection by Henneguya sp. (Myxozoa) in the bone tissue of the gill filaments of the Amazonian catfish Hypophthalmus marginatus (Siluriformes)
(Universidade Federal do Pará, 2015-09) SILVA, Michele Velasco Oliveira da; VIDEIRA, Marcela Nunes; SINDEAUX NETO, José Ledamir; SANTOS, Patricia dos; SANCHES, Osimar de Carvalho; MATOS, Patrícia Santos
This study describes aspects of the infection caused by the myxosporean genus Henneguya, which forms cysts in the bony portion of the gill filaments of Hypophthalmusmarginatus. Specimens of this catfish were acquired dead from artisanal fishermen near the town of Cametá, state of Pará, northern Brazil, between July 2011 and May 2012. They were transported in refrigerated containers to the Carlos Azevedo Research Laboratory at the Federal Rural University of Amazonia, in Belém, where analyses were performed. After confirmation of parasitism by the genus Henneguya, observation were made using optical and differential interference contrast (DIC) microscopy. The histological technique of embedment in paraffin was used. Ziehl-Neelsen staining was applied to the histological sections. Necropsy analyses on specimens of H. marginatus showed that 80% of them (40/50) had cysts of whitish coloration inside the bony portion of the gill filaments, filled with Henneguya spores. The present study found inflammatory infiltrate in the vicinity of the cysts. Furthermore, the special Ziehl-Neelsen staining technique made it possible to mark the Henneguya sp. cysts in the bone tissue and in spore isolates in the gill tissue structure. The descriptions of these histopathological findings show that this parasite is very invasive and causes damage to its host tissues.