title: Improved preparation and swimming behavior of Triton-extracted models of Didinium nasutum.
abstract: An improved method for the preparation of Triton X-100 extracted models of Didinium nasutum was established. Didinium models prepared by treatment with a Triton X-100 solution, containing specific proteolysis inhibitors and dimethyl sulfoxide, maintained an intact shape at 25 degrees C for a longer time than models prepared by treatment with a Triton X-100 solution not containing the proteolysis inhibitors and dimethyl sulfoxide. The improved Didinium models were reactivated so as to swim forward in the presence of Mg2+ and ATP or ADP. They did not swim backward in response to Ca2+, in contrast to well-known Paramecium models. However, the improved Didinium models showed circular swimming and spinning in response to 10(-6) M or higher concentrations of Ca2+. This observation suggests that the quick directional change as well as the spinning, which are characteristic of live Didinium, are due to an increase in the endoplasmic Ca2+ concentration around the ciliary system. The response of the Didinium ciliary system to Ca2+ may differ from the response of the Paramecium ciliary system to Ca2+.
authors.affiliation: Department of Physics, Waseda University, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Iwadate
authors.forename: H
authors.initials: H
authors.lastname: Asai
mesh_terms: D000255:Adenosine Triphosphate / Q000493:pharmacokinetics; D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics; D002465:Cell Movement; D002923:Cilia / Q000502:physiology; D004121:Dimethyl Sulfoxide; D016799:Kinetofragminophorea / Q000502:physiology* / Q000648:ultrastructure; D008274:Magnesium / Q000493:pharmacokinetics; D008961:Models, Structural; D009994:Osmolar Concentration; D011092:Polyethylene Glycols; D011480:Protease Inhibitors; D013550:Swimming / Q000502:physiology; D013997:Time Factors
chemical_list: D011480:Protease Inhibitors; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate; D008274:Magnesium; D002118:Calcium; D004121:Dimethyl Sulfoxide