[Structure and ultrastructure of the ovary of Cichlasoma urophthalmus (Osteichthyes: Cichlidae)]. / Estructura y la ultraestructura del ovario de Cichlasoma urophthalmus (Perciformes: Cichlidae).

The study of the normal development, differentiation, structure and function of various components of developing follicles in the ovaries of numerous fish species have been a consistent focus of comparative reproduction. The structural and ultrastructural features of gonads from Cichlasoma urophthalmus have received scarce attention. In this work, we realized a descriptive study of female gonads of Cichlasoma urophthalmus. A total of 40 samples were collected in the Veracruz Alvarado Lagoon, Mexico in 2007-2008 period including the windy, dry and rainy seasons. Female gonads were extracted and a portion was fixed in 4% formaldehyde for treatment for routine histology hematoxylin and eosin (HE) and another part was processed for transmission electron microscopy (TEM). The gonads were fixed in 3% glutaraldehyde and 2% osmium tetroxide, followed by dehydrated in ethanol 50%, 70%, 80%, 95% and 100% for inclusion in Epon, thin sections were then prepared and were contrasted with lead citrate and uranyl acetate. The process of oocyte development can be divided into five distinct stages (formation of oocytes from oogonia, primary growth, lipid stage, vitellogenesis and maturation). In this work, we found that the primary growth stage is characterized by intense RNA synthesis and the differentiation of the vitelline envelope. Secondary growth starts with the accumulation of lipid droplets in the oocyte cytoplasm (lipid stage), which is then followed by massive uptake and processing of proteins into yolk platelets (vitellogenic stage). During the maturation stage, the lipid inclusions coalesce into a single oil droplet, and hydrolysis of the yolk platelets leads to the formation of a homogeneous mass of fluid yolk in mature eggs. In conclusion, further studies should elucidate structure and ultrastructural changes in the ovarian follicular components, in C. urophthalmus during different stages of oocyte growth.

Estructura y la ultraestructura del ovario de Cichlasoma urophthalmus (Perciformes: Cichlidae)

Structure and ultrastructure of the ovary of Cichlasoma urophthalmus (Osteichthyes: Cichlidae). The study of the normal development, differentiation, structure and function of various components of developing follicles in the ovaries of numerous fish species have been a consistent focus of comparative reproduction. The structural and ultrastructural features of gonads from Cichlasoma urophthalmus have received scarce attention. In this work, we realized a descriptive study of female gonads of Cichlasoma urophthalmus. A total of 40 samples were collected in the Veracruz Alvarado Lagoon, Mexico in 2007-2008 period including the windy, dry and rainy seasons. Female gonads were extracted and a portion was fixed in 4% formaldehyde for treatment for routine histology hematoxylin and eosin (HE) and another part was processed for transmission electron microscopy (TEM). The gonads were fixed in 3% glutaraldehyde and 2% osmium tetroxide, followed by dehydrated in ethanol 50%, 70%, 80%, 95% and 100% for inclusion in Epon, thin sections were then prepared and were contrasted with lead citrate and uranyl acetate. The process of oocyte development can be divided into five distinct stages (formation of oocytes from oogonia, primary growth, lipid stage, vitellogenesis and maturation). In this work, we found that the primary growth stage is characterized by intense RNA synthesis and the differentiation of the vitelline envelope. Secondary growth starts with the accumulation of lipid droplets in the oocyte cytoplasm (lipid stage), which is then followed by massive uptake and processing of proteins into yolk platelets (vitellogenic stage). During the maturation stage, the lipid inclusions coalesce into a single oil droplet, and hydrolysis of the yolk platelets leads to the formation of a homogeneous mass of fluid yolk in mature eggs. In conclusion, further studies should elucidate structure and ultrastructural changes in the ovarian follicular components, in C. urophthalmus during different stages of oocyte growth. Rev. Biol. Trop. 59 (2): 743-750. Epub 2011 June 01.

Se realizó un estudio descriptivo de las gónadas femeninas de Cichlasoma urophthalmus. Las muestras fueron recolectadas en la Laguna de Alvarado Veracruz, México en el período 2007-2008 que incluyó las temporadas de Nortes, Secas y Lluvias. Se extrajeron las gónadas femeninas y una parte se fijó en formol al 4% para su tratamiento por técnica histológica de rutina hematoxilina y Eosina (H-E) y otra parte se procesó para microscopia electrónica de transmisión. Las gónadas se fijaron en glutaraldehído al 3% y OsO4 al 2%, se deshidrataron en etanol de 50 al 100% para ser incluidas en Epón. Se realizaron cortes finos y semifinos contrastados con citrato de plomo y acetato de uranilo. Los ovarios de C. urophthalmus son pareados presentan un desarrollo asincrónico con ovocitos previtelogénicos en estadio perinuclear tardío, asociados a las lamelas ovígeras y ovocitos vitelogénicos del VII estadio, éstos últimos presentan una zona radiada bien definida, con gránulos de vítelo lipídico y vesículas de vítelo proteico que se distribuyen en capas concéntricas, que rodean al núcleo. El presente estudio, permitió conocer más a fondo los cambios de la estructura y ultraestructura de los componentes de los folículos ováricos, en C. urophthalmus durante las diferentes etapas de crecimiento de los oocitos.

Macrophage migration inhibitory factor (MIF) is critical for the host resistance against Toxoplasma gondii.

Macrophage migration inhibitory factor (MIF) exerts either a protective or a deleterious role in the immune response to different pathogens. We analyzed herein the role of MIF in the host control of toxoplasmosis using MIF(-/-) mice backcrossed to either the BALB/c or the C57BL/6 genetic backgrounds. Both, wild-type (WT) BALB/c and MIF(-/-) BALB/c mice were susceptible to infection with highly virulent RH as well as moderately virulent ME49 strains of T. gondii. MIF(-/-) mice, however, showed greater liver damage and more brain cysts, produced less proinflammatory cytokines, and succumbed significantly faster than WT mice. Bone marrow-derived dendritic cells (BMDCs) from MIF(-/-) mice produced less interleukin-1beta, interleukin-12, and tumor necrosis factor-alpha than WT BMDCs after stimulation with soluble Toxoplasma antigen (STAg). Similar observations were made in CD11c(+) low-density cells isolated from the spleens of MIF(-/-) mice challenged with STAg. MIF(-/-) C57BL/6 mice succumbed to ME49 infection faster than their WT counterparts. C57BL/6 mice that succumbed to infection with the ME49 strain produced less MIF than resistant BALB/c mice similarly infected. Interestingly, an analysis of brains from patients with cerebral toxoplasmosis showed low levels of MIF expression. Together, these findings demonstrate that MIF plays a critical role in mediating host resistance against T. gondii.