Background: Malassezia pachydermatis is the main causative agent of canine otitis and also of a myriad of dermatological problems in companion animals; its interaction mechanisms with host cells are still unclear. Objectives: To establish an in vitro infection model of M. pachydermatis-exposed RK13 cells in order to evaluate cell morphological changes as well as changes in the structure of actin filaments. Methods: Cultures of RK13 cells were infected with M. pachydermatis, alterations caused by the yeast were evaluated by optical and fluorescence microscopy. Results: M. pachydermatis adheres itself to the cell and produces the formation of multiple agglomerates that cause changes in cell morphology, formation of cell aggregates in overlays, presence of syncytia and destruction of cell culture structure. The damaged cells presented changes in the actin filaments consisting of thickening of the cell cortex and loss of stress fibers. On the other hand, the formation of perinuclear actin rings in the yeasts was observed. Conclusions: An in vitro infection model was established with M. pachydermatis and alterations in cell morphology were observed consisting of changes in the structure of the actin filaments, overgrowth of the cells and the presence of syncytia.
Tight junctions are mainly formed by two types of proteins; claudins and occludin, both of which are fundamental to maintain the integrity and barrier function of the intestinal epithelium. This barrier function allows for the absorption of nutrients, mainly by transcytosis; however, in birds, 90% of the substances are absorbed by paracellular mechanisms. Despite this, claudins present in the different parts of the intestinal tract of adult chickens are not known, much less their functional role. This study aimed to determine the presence of mRNA of claudins 1, 2, 3, 5, 10, 12, 16 and occludin, in the different regions of the intestine (duodenum, jejunum, ileum, cecum, and rectum) in chickens (Gallus gallus domesticus
Las plumas se han utilizado para estudiar procesos de diferenciación celular y morfogénesis. Existen pocos estudios histológicos en animales adultos que describan de manera secuencial la maduración de los componentes celulares durante el crecimiento; así que el objetivo de este trabajo fue describir las características histológicas de este proceso, abarcando los elementos celulares y sus relaciones anatómicas. Se obtuvieron plumas remeras de palomas, en las que se había inducido un proceso de regeneración, a los 8, 13, 18, 23 y 28 días de crecimiento. Se realizaron cortes histológicos teñidos con diferentes técnicas. Se demostró la presencia de la zona ramogénica, que tiende a disminuir de tamaño del día 8 al 28. En las crestas de la barba se observaron células de la barba, barbulares y de la placa axial, quedando cada cresta delimitada por la placa marginal. Las características celulares variaron de acuerdo con la región de las crestas, mostrando en la placa marginal transiciones de células escamosas a cuboides y nuevamente a escamosas, y, por otro lado, en la placa barbular de células cuboides a columnares y después a fusiformes. Se identificaron las células obscuras de la zona ramogénica, las cuales, por sus características tintoriales, parecen derivar de la papila dérmica. En conclusión, se realizó la caracterización histológica del cálamo y se describió, por primera vez, de manera secuencial en las diferentes etapas del crecimiento.
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