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Synchronous exocytosis in Paramecium cells was analyzed on a subsecond time scale. For this purpose we developed a quenched flow device for rapid mixing and rapid freezing of cells without impairment (time resolution in the millisecond range, dead time approximately 30 ms). Cells frozen at defined times after stimulation with the noncytotoxic secretagogue(More)
In Paramecium tetraurelia, polyamine-triggered exocytosis is accompanied by the activation of Ca2+-activated currents across the cell membrane (Erxleben. C., and H. Plattner. 1994. J. Cell Biol. 127:935-945). We now show by voltage clamp and extracellular recordings that the product of current x time (As) closely parallels the number of exocytotic events.(More)
Exocytosis of trichocysts in Paramecium cells was generally believed to depend on extracellular Ca, since it is accompanied by a Ca influx and not seen in the absence of Ca. However, by short term removal of Ca we showed recently that only extrusion of secretory contents, but not membrane fusion after stimulation with aminoethyldextran (AED), depends on(More)
We had previously shown that an influx of extracellular Ca2+ (Ca2+ e ), though it occurs, is not strictly required for aminoethyldextran (AED)-triggered exocytotic membrane fusion in Paramecium. We now analyze, by quenched-flow/freeze-fracture, to what extent Ca2+ e contributes to exocytotic and exocytosis-coupled endocytotic membrane fusion, as well as to(More)
Rhodaminylated (R)-phalloidin microinjected into Paramecium tetraurelia cells at a final concentration of greater than or equal to 20 micrograms/ml produces considerable functional and structural changes. F-actin bundles (with 20 micrograms/ml phalloidin within 15 min) are formed, which subsequently (greater than 30 min) are sequestered into autophagic(More)
In Paramecium tetraurelia , polyamine-triggered exocytosis is accompanied by the activation of Ca 2 ϩ-activated currents across the cell membrane (Erx-leben, C., and H. Plattner. 1994. J. Cell Biol. 127:935– 945). We now show by voltage clamp and extracellular recordings that the product of current ϫ time (As) closely parallels the number of exocytotic(More)
Glutamate is an attractant stimulus to Paramecium tetraurelia. It causes a hyperpolarization of the cell and smooth, relatively fast swimming that is characteristic of hyperpolarizing stimuli. We show here that by 1-30 seconds of stimulation, glutamate increases intracellular cAMP. Interestingly, other attractant stimuli, such as acetate and NH4Cl, that(More)
BACKGROUND Epidermal growth factor receptor inhibitors are widely prescribed anticancer drugs. Patients treated commonly develop dermatologic adverse drugs reactions, but rarely they are involved in systematic evaluation of their quality of life. This monocentric cross sectional study is carried out to assess quality of life in colon cancer patients(More)
Paramecium tetraurelia wild-type (7S) cells respond to 2.5 mm veratridine by immediate trichocyst exocytosis, provided [Ca2+] o (extracellular Ca2+ concentration) is between about 10−4 to 10−3 m as in the culture medium. Exocytosis was analyzed by light scattering, light and electron microscopy following quenched-flow/ freeze-fracture analysis. Defined(More)
Post kala-azar dermal leishmaniasis (PKDL) is the dermal sequel of visceral leishmaniasis (VL) and occurs after apparent cure or alongside with VL. It is confined to South Asia (India, Nepal and Bangladesh) and East Africa (mainly Sudan), the incidence being 5-10% and 50-60% respectively. In South Asia, as the transmission of VL is anthroponotic, PKDL(More)
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