...Kazuyuki Sugino; Takashi Tominaga; Richard D. Allen; Yutaka Naitoh SUMMARY The contractile vacuole complex of Paramecium multimicronucleatum transforms into membrane-bound vesicles on excision from the cell. The I – V relationship was linear in a voltage range of–80 to +80 mV in all vesicles...

...Masaaki Iwamoto; Richard D. Allen; Yutaka Naitoh SUMMARY The freshwater ciliated protozoan, Paramecium multimicronucleatum ,usually possesses two contractile vacuole complexes (CVCs). The number of CVCs in a single cell, however, may vary from 1 to 7. We found that the number of cells that have...

...Heidi K. Grønlien; Christian Stock; Marilynn S. Aihara; Richard D. Allen; Yutaka Naitoh SUMMARY The electric potential of the contractile vacuole (CV) of Paramecium multimicronucleatum was measured in situ using microelectrodes,one placed in the CV and the other (reference electrode) in the cytosol...

...Christian Stock; Richard D. Allen; Yutaka Naitoh ABSTRACT The rate of fluid expulsion, R CVC , from the contractile vacuole complex (CVC) of Paramecium multimicronucleatum was estimated from the volume of the contractile vacuoles (CVs) immediately before the start of fluid discharge and from...

...Tomomi Tani; Richard D. Allen; Yutaka Naitoh ABSTRACT The contractile vacuole of the freshwater protozoan Paramecium multimicronucleatum is a membrane-bound exocytotic vesicle that expels excess cytosolic water. The in vitro contractile vacuole isolated from P. multimicronucleatum along...

...Takashi Tominaga; Richard D. Allen; Yutaka Naitoh ABSTRACT The freshwater protozoan Paramecium multimicronucleatum maintains a constant cytosolic osmolarity through the exocytotic activity of its contractile vacuole complex. The contractile vacuole (CV) expels the excess cytosolic water, acquired...

... aquaporin Paramecium multimicronucleatum The contractile vacuole complex is a membrane-bound osmoregulatory organelle observed in freshwater protozoa and sponges (Jeeps, 1947 ; Patterson, 1980). The organelle of Paramecium multimicronucleatum consists of a central contractile vacuole (CV...

...Yutaka Naitoh; Takashi Tominaga; Richard D. Allen ABSTRACT The precise relationship between the rate of contractile vacuole fluid discharge and the vacuole diameter at the start of systole was determined in cells of Paramecium multimicronucleatum subjected to various external conditions. The rate...

...Yasuo Nakaoka; Tohru Tanaka; Toshihiko Kuriu; Tomohisa Murata ABSTRACT The possible involvement of G-proteins in cold-sensory transduction was examined using voltage-clamped Paramecium multimicronucleatum into which non-hydrolyzable guanosine nucleotide analogues had been applied intracellularly...

...Yutaka Naitoh; Takashi Tominaga; Masaki Ishida; Agnes K. Fok; Marilynn S. Aihara; Richard D. Allen ABSTRACT To examine the forces needed for discharge of the fluid contents from the contractile vacuole of Paramecium multimicronucleatum , the time course of the decrease in vacuole diameter during...

...Ken-Ichi Okamoto; Yasuo Nakaoka ABSTRACT In conditions in which ciliated cortical sheets prepared from detergent-extracted Paramecium multimicronucleatum cells adhered to glass coverslips on a microscope stage, perfusion of a reactivation medium containing ATP plus cyclic AMP or cyclic GMP...

...Ken-Ichi Okamoto; Yasuo Nakaoka ABSTRACT We reconstituted metachronal waves on ciliated cortical sheets prepared from detergent-extracted Paramecium multimicronucleatum cells. Ciliary movements of the cortical sheet, whose intracellular side adhered to a glass coverslip, were reactivated...