No abstract
The distribution of actin filaments in pyloric gland cells of cattle was studied with respect to their functional significance in the process of exocrine secretion by use of rhodamine-phalloidin labelling and immunogold-electron microscopy based on the biotin-streptavidin bridge technique. Actin concentrates on the filamentous network of the luminal-cell cortex. Membranes of secretory vesicles accumulating in the cell cortex are also labelled for actin. The present results support the concept of a barrier function of cortical microfilaments entrapping vesicles and linking them to the cytoskeleton. In addition, intracellular localization of calcium-ATPase activity was determined. Enzyme activity associated with the microfilamentous cortical matrix is supposed to be of cytoskeletal nature indicating participation of myosin (-like) structures in the dynamic secretion event. Deposition on the interior aspect of secretory vesicle membranes points to an ATPase transporting calcium into these organelles and enabling them to participate via storage of the cation in intracellular calcium homeostasis, thereby influencing the functional architecture of the cortical cytoskeleton.
Zusammenfassung Mit Hilfe elektronenoptischer und zytochemischer Methoden wird der Nachweis partikel‐gebundener und nicht‐partikelgebundener saurer Phosphatase geführt. Die Befunde zeigen, daβ im Pansenepithel Lysosomen sowohl der autophagen als auch der heterophagen Richtung (de Duve) vorkommen. Daraus wird die Vorstellung abgeleitet, daβ die Autolysosomen sowie diffus ins Cytoplasma freigesetzte Enzyme eine sehr spezifische Hornzelle differenzieren und die Heterolysosomen sowie die auf die Zelloberfläche sezernierten Enzyme den Stoffaustausch auch durch die Barrierenschicht des Epithels vermitteln und kontrollieren dürften. Summary Electron‐microscopical studies on lysosomes in the ruminal epithelium in the goat With the help of electron‐optical and cytochemical methods, the presence of particle‐bound and non‐particle‐bound acid phosphatases was demonstrated. The findings show that lysosomes in the ruminal epithelium are both autophage and heterophage (De Duve). This suggests the hypothesis that auto‐lysosomes, as well as enzymes lying free in the cytoplasm, have a very specific relationship to cornified cells and that hetero‐lysosomes, as well as enzymes, secreted on the cell surface, participate in the exchange of substances across the epithelial barrier and assist in their control. Résumé Examens des lysosomes de l'épithélium du rumen de la chèvre au microscope électronique On démontre la présence de phosphatases acides libres ou liées aux particules, au moyen de méthodes optiques électroniques et cytochimiques. Ces observations montrent que l'on trouve dans l'épithélium du rumen des lysosomes à tendance soit autophage, soit hétérophage (De Duve). Ceci suggère l'hypothèse que les autolysosomes, de même que les enzymes libérés dans le cytoplasme de façon diffuse, différencieraient spécifiquement la cellule cornée, alors que les hétérolysosomes, de même que les enzymes sécrétés à la surface de la cellule, participeraient aux échanges de substances même au travers de la barrière formée par l'épithélium et les contrôleraient. Resumen Estudios electrónicomicroscópicos con lisosomas en el epitelio del rumen de cabra Con ayuda de técnicas electrónicoópticas y citoquímicas se identifica la fosfatasa ácida ligada a la partícula y la no fijada a la partícula. Los hallazgos muestran que en el epitelio de la panza se hallan lisosomas tanto de dirección autófaga como de la heterófaga (De Duve). De aquí se deriva el concepto de que los autolisosomas, así como las enzimas puestas en libertad de forma difusa en el citoplasma diferencian una célula cónea muy específica y los heterolisosomas, así como las enzimas secretadas sobre la superficie celular también deberín intervenir y controlar el intercambio de materias mediante la capa de barreras del epitelio.
The morphology of the marginal lingual papillae in eight newborn pigs aged 1-5 days was examined at the light-microscopical level, as well as, for the first time, using electron transmission and scanning methods. The papillae marginales are arranged tuft-like or rosetted with chief and accessory papillae, the individual papillae varying considerably in shape. Leaf-, tongue- or fingerlike and conical shapes predominate. The stratified squamous epithelium is either keratinized, resembling the epidermal differentiation pathway, or non-keratinized, according to the mucosal pathway. The characteristic morphology of keratinocyte differentiation is shown with special reference to the establishment of the permeability barrier. The connective tissue papillae are intensively surface-enlarged by means of multiple fingerlike protrusions.
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