Ultrastructural Aspects of Spermatogenesis in Phalloceros caudimaculatus (Teleostei, Poeciliidae)

The aim of the present study was to analyze the ultrastructural aspects of spermatogenesis in Phalloceros caudimaculatus, during cell proliferation. The parenchyma is organized morphologically as lobular restricted spermatogonial testis. Spermiogenesis in this species is characterized by four morphological stages of development (spermatids S1 through S4). The mature spermatids and spermatozoa heads are situated at the periphery of the cyst surrounded by the cytoplasm of the Sertoli cells. The germ cell's ultrastructure and spermatogenesis in P. caudimaculatus are very similar to that of other poeciliids.El objetivo del presente estudio fue analizar los aspectos ultraestructurales de la espermatogénesis en Phalloceros caudimaculatus, durante el periodo de proliferación celular. El parénquima testicular está morfológicamente organizado como lobular espermatogonial restricto. La espermiogénesis en esta especie se caracteriza por cuatro etapas morfológicas de desarrollo (espermátidas S1 hasta S4). Las cabezas de las espermátidas maduras y espermatozoides están situadas en la periferia de los cistos, rodeados por el citoplasma de las células de Sertoli. La ultraestructura de las células germinativas y la espermatogénesis en P. caudimaculatus son muy similares a las de otros poecílideos.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Light microscopy and ultrastructure ight of the liver of Astyanax altiparanae Garutti and Britski, 2000 (Teleostei, Characidae) = Histologia e ultraestrutura do fígado de Astyanax altiparanae Garutti e Britski, 2000 (Teleostei, Characidae)

Livers of thirty specimens of Astyanax altiparanae obtained from a commercial fish farm were subjected to light and transmission electron microscopy, in order to describe the hepatic parenchyma and the intrahepatic exocrine pancreatic tissue. Anatomically, theliver showed only three hepatic lobes. Histological analysis demonstrated that the hepatocytes were spread out as anastomotic cords, arranged in two cellular layers and surrounded by sinusoids. The intrahepatic exocrine pancreatic tissue exhibited an acinararrangement and was diffused in the hepatic parenchyma. Ultrastructural analysis showed that the hepatocytes had a rounded nucleus and a rough endoplasmatic reticulum, with a parallel disposition to the nuclear membrane. The exocrine pancreatic cells showed secretion granules at the apical portion, and the rough endosplasmatic reticulum was concentrically distributed.<br><br>Fígados de 30 exemplares de Astyanax altiparanae, obtidos de pesqueiros, foram submetidos à microscopia de luz e à microscopia eletrônica de transmissão para descrição do parênquima hepático e do tecido pancreático exócrino intrahepático. Anatomicamente, o fígado apresenta somente três lobos hepáticos. A análise histológica demonstra que os hepatócitos se encontram arranjados na forma de cordões anastomosados, dispostos em duas camadas celulares, sendo que estes estão cercados por sinusóides. O tecido pancreático exócrino intra-hepático apresenta arranjo acinar difuso pelo parênquima hepático. A análise ultraestrutural demonstra que os hepatócitos possuem um núcleo arredondado e retículo endoplasmático rugoso, com disposição paralela à membrana nuclear. As células pancreáticas exócrinas apresentam grânulos de secreção na porção apical e retículo endoplasmático rugoso com distribuição concêntrica

altiparanae Garutti and Britski, 2000 (Teleostei, Characidae)

Light ight microscopy and ultrastructure of the liver of Astyanax styana

<b>Estudo morfológico do tecido hepático de <em>Leporinus macrocephalus</em></b> - DOI: 10.4025/actascibiolsci.v29i1.157 Morphological study of the hepatic tissue of <em>Leporinus macrocephalus</em>

O presente trabalho objetivou análise macroscópica e histológica do fígado de <em>Leporinus macrocephalus</em> para avaliar a estrutura do tecido hepático. Os peixes provenientes de um pesqueiro da região de Bauru, Estado de São Paulo, foram anestesiados, mortos, e os fígados foram retirados e encaminhados à rotina histológica, com inclusão em paraplast. A macroscopia mostrou um figado de estrutura homogênea, de coloração marron-avermelhada, localizado na região medial do corpo, caudalmente ao coração e posterior às brânquias, apresentando três lóbos de forma piramidal, sendo um central e dois laterais direito e esquerdo. A análise histológica revelou o tecido hepático constituído por cordões duplos de hepatócitos circundados por sinusóides, denominado de “muralha dupla”. Revelou, ainda, um sistema biliar disperso pelo parênquima hepático mostrando ductos com epitélio cúbico simples, circundado por fibras musculares e tecido conjuntivo. Células do tecido pancreático exócrino foram observadas, margeando vasos sangüíneos, organizando-se em ácinos apresentando grânulos de zimogênio. Além disso, existem centros melanomacrófagos distribuídos ao longo de todo parênquima, preferencialmente próximos aos vasos sanguíneos, formados por células que acumulam materiais como melanina e lipofucsina, podendo sua presença estar relacionada com o estado nutricional do peixe<br>The objective of this work was to analyze the liver of <em>Leporinus macrocephalus</em> at the macroscopic and histologic level by evaluating the characteristics of the hepatic tissue. The fishes from a fishery in Bauru, S.P., were collected and sacrificed by destroying the spinal cord; afterwards the collected hepatic tissue was fixed and followed by histological routine. Macroscopic analysis of <em>L. macrocephalus</em> liver showed an organ of homogeneous structure, with red-brown color, located in the medial region of the body, caudal to heart and after the gills. It showed 3 pyramidal lobes, one central and two lateral right and left. The histological analysis showed the hepatic tissue constituted by hepatocytes cords surrounded by sinusoids, named “muralium duplex”. It yet revealed the diffused, distribution bile system by hepatic parenchyma, showing ducts with simple cubic epithelium, surrounded by muscular fibres and connective tissue. Cells of the exocrine pancreatic tissue were observed surrounding blood vessels in acinar arrangement as zymogen granules. Furthermore, there are melanomacrophages centers distributed along the hepatic parenchyma, preferably next to the blood vessels, constituted by cells accumulating material, such as melanin and lipofucsin, whose presence may be related to the nutritional status of the fis

Testicular structure and description of the seminal pathway in Leporinus macrocephalus (Anostomidae, Teleostei)

The present study examined the testicular structure and the seminal pathway in freshwater fish Leporinus macrocephalus (Garavello and Britski, 1988). Twenty-five specimens of this species were studied. Testicular structure was analyzed using light and transmission electron microscopy. The testicular main ducts were examined by means of conventional histology, corrosion-cast technique and scanning electron microscopy. Additional techniques were applied for polysaccharides histochemistry and immunohistochemistry for androgen receptor. The testicular parenchyma was classified as the anastomosing tubular testis type with spermatogonia occurring along the lengths of the seminiferous tubules. The seminiferous tubules emptied directly into the testicular main ducts. The wall of the testicular main ducts in L macrocephalus consisted of three layers: epithelium, connective tissue and peritoneum. The epithelium changed from simple cuboidal to pseudostratified. The histochemical analysis revealed the presence of granules PAS positive in the epithelial cells. The immunoreactivity to androgen receptor was noted in the testicular main ducts through all cytoplasmic areas of epithelial cells. (C) 2011 Elsevier Ltd. All rights reserved.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Diferenciação morfotípica de machos do camarão de água doce Macrobrachium amazonicum a partir da análise do hepatopâncreas e do sistema reprodutor - DOI: 10.4025/actascianimsci.v26i4.1720

Adult males of the freshwater prawn Macrobrachium amazonicum from a same-age population can be categorized in four morphotypes, according to external morphologic characteristics. Each morphotype represents a different stage in the growth of adult males, starting with translucent claw (TC), followed by cinnamon claw (CC), then green claw 1 (GC1) and, finally, green claw2 (GC2). However, they can be categorized three morphotypes, according to testis internal morphology. To clarify in part these observations, 40 male prawns were selected from a single-age population bred at the Aquaculture Center of Unesp. The reproductive system and the hepatopancreas of each animal, from all morphotypes, were measured and compared. The reproductive system growth was a sexual activity indicator. Also, hepatopancreas growth was found to be related to somatic growth. The hepatopancreas growth was significantly higher in the CC morphotype when compared to the TC morphotype, and the reproductive system growth was significantly higher in GC1 morphotype than in CC morphotype. All the males of the morphotypes TC, CC, GC1 and GC2 showed significant difference in body weigh; however, the difference between GC1 and GC2 morphotypes was due to the significant growth in the claw length and not to reproductive system and hepatopancreasMachos adultos do Macrobrachium amazonicum de uma população com a mesma idade podem ser categorizados em quatro morfotipos, de acordo com as características morfológicas externas. Cada morfotipo representa um estágio diferente de crescimento e varia de acordo com a cor e o comprimento do quelípodo. São encontrados machos com quela translúcida (QT), quela canela (QC), quela esverdeada (QE) e, finalmente, machos com quela verde intenso (QVI). No entanto, a morfologia interna dos testículos categoriza os machos adultos dessa espécie em três morfotipos. Na tentativa de esclarecer essas observações, 40 machos de mesma idade foram selecionados de uma população, mantida no Setor de Carcinicultura do Caunesp. O sistema reprodutor e o hepatopâncreas de cada animal de cada morfotipo foram pesados e comparados. Utilizou-se o crescimento do sistema reprodutor como indicador da atividade sexual. Da mesma forma, o crescimento do hepatopâncreas foi relacionado ao crescimento somático. No presente trabalho, o crescimento do hepatopâncreas foi maior (p<0,05) no morfotipo QC em relação ao QT. Todavia, o crescimento do sistema reprodutor apresentou-se maior (p<0,05) nos morfotipos QE em relação ao QC. Todos os machos dos morfotipos QT, QC, QE e QVI apresentaram diferença (p<0,05) no peso do corpo. Mas, a diferença entre os morfotipos QE e QVI foi devida ao crescimento do comprimento da quela, e não ao crescimento do sistema reprodutor e do hepatopâncreas. O presente trabalho mostrou que de acordo com os índices Gonadossomático e Hepatossomático, a espécie M. amazonicum apresenta três morfotipos distintos: QT, QC e QVI

Structural analysis of fertilization in the fish Brycon orbignyanus

In the present work, we analyzed the structure of oocytes and fertilized eggs of the piracanjuba fish (Brycon orbignyanus) under light and scanning electron microscopy. After inducing spawning, samples were collected at the moment of oocyte extrusion, when oocytes and semen were mixed (time 0), as well as at 10, 20 and 30s after mixing, every minute up to 10 min, and then at 15 and 20 min. The oocytes are spherical, translucent and greenish with a mean diameter of 1.3 +/- 0.11 mm. During the extrusion, cytoplasmic movement was observed in eggs towards the micropyle, characterizing the animal pole. At the moment of fertilization, the cortical cytoplasm showed a higher concentration of cortical alveoli at the animal pole than at the vegetal pole. The cortical alveoli breakdown promoted the elevation of the chorion with a consequent increase in egg diameter (1.95 +/- 0.08mm). The penetration of the spermatozoon promotes the formation of a fertilization cone of spherical external structure, which obstructs the opening of the micropyle. This structure acts as a main mechanism to avoid polyspermy, intercepting the access of supernumerary spermatozoa. Such studies about the reproductive biology of fish are important to species survival and conservation programmes.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq