Effects of Intracellular Vanadate on Electrogenesis, Excitability and Cytoplasmic Streaming in Nitellopsis obtusa

元データ 日本植物生理学会


Vanadate, which is known to inhibit the plasma membrane H+-ATPase of Neurospora, was applied intracellularly to internodal cells of Nitellopsis by use of the intracellular perfusion technique. It inhibited electrogenesis and H+-extrusion, evidence that the electrogenic pump of the Characeae plasmalemma is the H+-extruding one. The concentration of Vanadate for the half-maximal inhibition of the activity of the pump was 5μM. The membrane potential and H+-extrusion occasionally recovered from vanadate inhibitions for reasons that are unknown. Membrane excitability, which is dependent on Mg・ATP, was not inhibited by vanadate, which suggests that the ATPase involved with membrane excitability differs from that of the H+ pump. Cytoplasmic streaming took place even when the cell was perfused with the medium containing 1 mM Vanadate, which indicates that the vanadate-insensitive actomyosin system is concerned with the motive force generation of the streaming.


Tazawa Masashi Department Of Botany Faculty Of Science University Of Tokyo
Shimmen Teruo Department Of Biology Faculty Of Science Osaka University:(present)department Of Botany Faculty Of S
Tazawa Masashi Departlnent Of Biology Faculty Of Science Osaka University