Phenotypic characterization of paranoiac and related mutants in Paramecium tetraurelia.

Paranoiac and related mutants of Paramecium tetraurelia display altered membrane excitability. We describe an extension of behavioral characterizations of the paranoiac, fast-2, and tetraethylammonium-insensitive mutants, comparing in detail their reactions to sodium stimulation under standard culture conditions, when grown at various temperatures and when starved. We also use freeze-fracture electron microscopic techniques to analyze in these stocks the morphology of organized arrays of membrane particles, the ciliary plaques.