title: Serine transport and membrane depolarization in the liverwort Riccia fluitans.
abstract: The plasmalemma of thallus cells of the aquatic liverwort, Riccia fluitans, is reversibly depolarized by L- and D-serine. At 0.1 mM K+ in the medium, the depolarization saturates at 50 mV; half-maximal depolarization occurs at 13 microM L-serine and 30 microM D-serine, respectively. Uptake of 14C-labelled L-serine depends upon the K+ concentration and is sensitive to the membrane potential as indicated by its reduction through 1 mM sodium cyanide. We propose that serine binds to and is transported by an electrogenic carrier. However, an interaction of serine with K+ channels of the membrane seems also possible.
mesh_terms: D001692:Biological Transport; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008564:Membrane Potentials; D010944:Plants / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D012694:Serine / Q000378:metabolism*
chemical_list: D012694:Serine; D011188:Potassium