title: A single gene mutation that affects a potassium conductance and resting membrane potential in Paramecium.
abstract: A new mutant of Paramecium tetraurelia has been isolated with a profound defect in the regulation of membrane potential. This mutant, restless, hyperpolarizes as a potassium electrode below 8 mM external K+ whereas wild-type cells can maintain a constant resting cell potential independent of low external K+ concentration. restless dies in solutions of low K+ concentration in which wild-type can survive indefinitely. restless is not allelic to mutations that affect the depolarization-dependent Ca2+ current, the Ca2+-activated K+ current, and the Ca2+-activated Na+ current. The results suggest that restless is a new class of mutant affecting a K+ conductance hitherto not characterized genetically in Paramecium.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D004553:Electric Conductivity; D005827:Genetics, Microbial; D008564:Membrane Potentials / Q000187:drug effects*; D009154:Mutation; D010247:Paramecium / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D011188:Potassium / Q000378:metabolism*; D013997:Time Factors
chemical_list: D011188:Potassium; D002118:Calcium