Über den Einfluß des hydrostatischen Druckes auf die Ultrastrukturen von Zellen und Geweben. II. Untersuchungen an membransystemen von Kiemenepithelien mariner Muscheln und dem Kiemendarm von Branchiostoma lanceolatum

Employing the technique of pressure fixation, high hydrostatic pressure effects on ultrastructures of membrane systems and cell organelles have been investigated, using as material the gill epithelium of marine bivalves and the pharynx epithelium of Branchiostoma lanceolatum (Pallas). Pressure was increased stepwise between 1 and 800 atm. Pressure sensivity of the tissues varies as a function of their structure and function. The degree of disorganization of cell structures increases with increasing pressure. At 300 to 500 atm, the microvilli tend to form small vsicles, which are connected with each other by thin filaments. Especially the basic vesicles become enlarged to oedematous expansions. A variety of membrane disintegrations can be observed on cell organelles, which are connected by membrane-flow. This supports the thesis of the heterogeneity of membranes. Mitochondria reveal destruction of the cristae to an electron-dense material. Membrane lysis can be demonstrated in the endoplasmic reticulum and the plasmalemma of spezialized pharynx cells of B. lanceolatum. The Golgi-apparatus is the only organelle which remains almost unaffected by hystrostatic pressure. There are probably interactions between pressure sensivity of membrane structures and their enzymatic activities.