Immunohistochemical expression of E–cadherin in different tissues of the teleost fish Scophthalmus maximus

E–cadherin is an evolutionary conserved protein, whose main role as the principal component of adherens junctions is supporting epithelial cell–cell adhesion. It is an essential molecule for the maintenance of the epithelial barrier function and the analysis of its immunohistochemical expression is a valuable resource in morphopathological, ontogenetic and pathogenesis studies in mammals. As well, there is an increasing understanding of the importance of E-cadherin in the physiology of the immune system and the development of the immune response. Mucosal health is a primary issue in aquaculture research; nevertheless, there is a lack of immunohistochemical studies of cell junction proteins in fish species. In this work, an immunohistochemical technique was optimized in Bouin- and formalin-fixed paraffin-embedded tissues of turbot Scophthalmus maximus, employing a commercial antibody raised against human E-cadherin. The specificity of the antibody in recognizing the molecule in this teleost species was tested by western blot and mass spectrometry-based proteomic analyses. The assays showed a good specificity and indicated that the antibody recognizes the well conserved cytoplasmic domain of the protein. Immunohistochemistry showed the localisation of E-cadherin at cell-cell contact in the epithelia of the different organs, between the hepatocytes and the pancreatic acinar cells, as well as in the reticulo-epithelial stroma of the thymus. Also, the immunoreaction was observed in the cells constituting the melano-macrophage centres in the spleen and kidney. No immunostaining was detected, as expected, only in the heart and brain. No significant difference was noticed between the two fixative used for collecting the tissues samples. This is the first description of E-cadherin immunohistochemical expression in several tissues of a teleost. The immunohistochemical technique represents a useful tool to be used in the different areas of fish health researchThis work was supported by the Spanish Ministry of Economy, Industry and Competitiveness, and the European Regional Development Fund (ERDF) through the projects AGL2015–67039–C3–1–R and AGL2015–67039–C3–3–RS

Chromosomal differences in Sabaletas (Brycon henni) from the upper basins of the Cauca and Patia rivers

This research chromosomically compared Sabaletas (Brycon henni) from the upper basins of the Cauca and Patia rivers in the Cauca department. For the study 6 specimens were captured in each site and transported to the Genetic toxicology laboratory of the Universidad del Cauca. Once there, kidney cells were extracted and cultivated, spreads of cells in metaphase were done, pictures were taken with an optical microscope, and the modal chromosome number and types of chromosomes were determined according to the position of the centromere, manually and using an assisted segmentation system for image processing. The results showed that Brycon henni has a chromosomal number of 2n=52, and two karyological formulas specific to each of the basins studied: Brycon henni from the Cauca river had the kariotype formula 22m+16sm+14st, while from the Patia river basin the formula was 8m+10sm+26st+8t. These differences suggest that the specimens studied from both basins are probably in a speciation process due to geographical isolation. Moreover, no differences in the chromosome number were found between males and females on both basins. Additionally, the physico-chemical parameters of the water from the upper basins of the Cauca and Patia rivers have not shown significant changes that could affect the physiological conditions of these fishes.Esta pesquisa realizou a comparação cromossômica da sabaleta (Brycon henni) pertencentes as bacias altas dos rios Cauca e Patía no departamento de Cauca. Para realizar o estudo foram capturados 6 exemplares de cada lugar e se trasladaram ao Laboratório de Toxicologia e Genética da Universidad del Cauca (Popayán, Cauca), uma vez ali, se processaram os cultivos celulares in vitro extraídos do rim, se realizaram os estendidos da metáfase, se tiraram as fotografias com microscópio ótico e se determinou o número cromossômico modal e o tipo de cromossomos segundo a posição do centrômero. Isto se fez em forma manual e com a ajuda de um sistema assistido de segmentação para o processamento de imagens. Com a utilização desta técnica encontrou-se que: a espécie Brycon henni apresenta um número cromossômico de 2n=52 e dois formulas cariológicas especificas para cada uma das bacias estudadas, assim: a formula cariológica do Brycon henni do rio Cauca foi: (22m+16sm+14st) e do Brycon henni do rio Patía: (8m+10sm+26st+8t). Estas diferenças sugerem que os exemplares estudados nas duas bacias provavelmente se encontram em processo de especiação devido ao isolamento geográfico. De outro lado, não se apresentaram diferenças no número de cromossomos entre machos e fêmeas de Brycon henni nas duas bacias estudadas. Do mesmo jeito, os parâmetros físico-químicos da agua das bacias dos rios Cauca e Patía não mostraram mudanças significativas que afetem as condições fisiológicas desta espécie de peixe.Esta investigación realizó la comparación cromosómica de la sabaleta (Brycon henni) pertenecientes a las cuencas altas de los ríos Cauca y Patía en el departamento del Cauca. Para el estudio fueron capturados seis ejemplares de cada sitio y se trasladaron al Laboratorio de Toxicología Genética de la Universidad del Cauca, una vez allí se procesaron cultivos celulares in vitro extraídos del riñón 5, 9, 16, realizados los extendidos de las metafases, se tomaron las fotografías con microscopio óptico y se determinó el número cromosómico modal y el tipo de cromosomas según la posición del centrómero, en forma manual y con ayuda de un sistema asistido de segmentación para el procesamiento de imágenes 23 (López y Pinto, 2007), mediante este método se obtuvo: que la especie Brycon henni presenta un número cromosómico de 2n=52 y dos fórmulas cariológicas específicas para cada una de las cuencas estudiadas así: Brycon henni del rio Cauca su fórmula cariológica fue: (22m+16sm+14st) y para Brycon henni de la cuenca del rio Patía (8m+10sm+26st+8t). Estas diferencias sugieren que los ejemplares estudiados en las dos cuencas probablemente se encuentren en proceso de especiación debido al aislamiento geográfico. Por otra parte no se presentaron diferencias en el número de cromosomas entre machos y hembras de Brycon henni en las dos cuencas estudiadas. Asimismo los parámetros físico-químicos del agua de las cuencas altas de los ríos Cauca y Patía no han mostrado cambios significativos que afecten las condiciones fisiológicas de estos peces