Intracellular pH and chemoresponse to NH4+ in Paramecium.
Paramecium are attracted to ammonium chloride solutions relative to sodium chloride control solutions, but little is known about the mechanisms by which attraction is evoked. A known effect of ammonium solutions in other cell types is an alteration of intracellular pH. We show here that intracellular pH is elevated upon initial exposure to 5 mM NH4Cl, but appears to decline within 10 minutes, both in wild type cells and in two mutants which do not show sustained attraction to NH4Cl using the standard behavioral assay, the T-maze. We also present quantitative values of swimming parameters that underlie the response to NH4Cl.
Davis
D P
DP
Department of Biology, University of Vermont, Burlington 05405-0068, USA.
Fiekers
J F
JF
Van Houten
J L
JL
D000643:Ammonium Chloride / Q000494:pharmacology*; D000818:Animals; D002633:Chemotaxis; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D018782:Maze Learning / Q000187:drug effects; D009154:Mutation; D010247:Paramecium / Q000187:drug effects* / Q000235:genetics; D013550:Swimming / Q000502:physiology; D014741:Video Recording
D000643:Ammonium Chloride