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The experimental opening and resealing of occluding junctions in monolayers of cultured MDCK cells (epithelioid of renal origin) was explored by measuring changes in the electrical resistance across the monolayer and by freeze-fracture electron microscopy. As in natural epithelia, the function of occluding junctions as permeability barriers specifically(More)
Madin-Darby canine kidney (MDCK) cells plated at confluence and incubated for 20 h in low (5 microM) Ca2+ have no tight junctions (TJs), and their Na+-K+-ATPase is randomly distributed over the surface. On transfer to normal Ca2+ levels (1.8 mM) ("Ca2+ switch"), TJs and transepithelial resistance develop quickly, trapping a considerable fraction (35%) of(More)
MDCK cells (epithelioid line derived from the kidney of a normal dog) form monolayers which retain the properties of transporting epithelia. In these cells viruses bud asymmetrically: influenza from the apical, and vesicular stomatitis (VSV) from the basolateral membrane (E. Rodríguez-Boulán and D. D. Sabatini,Proc. Natl. Acad. Sci. USA 75: 5071–5075, 1978;(More)
We have studied whether ammonia crosses the cristae membrane of rat liver mitochondria as a charged (NH4+) or an uncharged (NH3) species. Passive swelling of mitochondria suspended in ammonium and/or sodium acetates showed that: swelling depends upon ammonium concentration in the same way it depends on sodium (at constant acetate concentration). The curves(More)
This paper reports the suitability of culturing a line of dog kidney epithelial cells, MDCK, in the presence of a serum substitute, Ultroser G. Serial subcultivation with this product was possible for at least 10 passages without any change in cell shape and size, saturation density, dome-forming ability, transepithelial resistance, and growth curve.(More)
We have studied the inhibitory effects of several cations (OG+, Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, La3+) on the uniport and exchange pathways for Na+ and K+ of rat liver mitochondria. Swelling of mitochondria suspended in sodium or potassium acetates indicates that: 1. Sodium passive influx to inhibited mitochondria is not affected by OG+ (in the microM range),(More)