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Activation of the Ca2+/Mg2+ ATPase associated with highly purified Torpedo synaptic vesicles results in 45Ca2+ uptake. The accumulated 45Ca2+ is released by hypoosmotic buffer and by the Ca2+ ionophore A23187. Density-gradient centrifugation and permeation chromatography reveal that vesicular acetylcholine and the membrane-bound 45Ca2+ co-migrate, thus(More)
In the human colon adenocarcinoma cell line HT29, tight junctions can be induced by treatment with appropriate proteases or salt solutions. The temperature dependence of induced tight junction formation is characterized by a marked sigmoidal behavior. The different methods of induction used in this study were characterized by threshold temperatures ranging(More)
In primary monolayer cultures of dispersed neural retina cells from 13-day chick embryo, gliocytes (Müller glia cells) multiply and rapidly change into a lentoidal (lens-like) phenotype. They express lens proteins, including MP26 (a lens plasma-membrane antigen) and ultra-structurally appear to resemble lens cells. A significant aspect of this modification(More)
The retina cognin (a retina-specific cell-surface glycosylated protein that mediates self-recognition and morphogenetic contact associations of embryonic retina cells) was visualized by immunolabeling and scanning electron microscopy on the surface of cells within retina tissue of 9- and 16-day chick embryos. The photoreceptor processes which are free of(More)
1. Addition of ATP to isolated highly purified Torpedo synaptic vesicles results in 45Ca2+ uptake. 2. Ca2+ dependent ACh release from Torpedo synaptosomes is accompanied by the phosphorylation of a specific protein with an apparent subunit molecular weight of about 100,000 (band alpha). 3. Activation of the presynaptic muscarinic receptors by an agonist(More)
Highly purified synaptic vesicles have been isolated from the electric organ of Torpedo ocellata by a rapid procedure which enables the concurrent isolation of synaptic vesicles and of intact presynaptic nerve endings (synaptosomes). The purification procedure consists of homogenization of fresh electric tissue in iso-osmotic glycine in the presence of(More)
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