[Bacterial flagellar motor].
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Adenosine Triphosphate↗
Biomedical subjects
N Kami-ike
Publications and source records attributed to N Kami-ike.
Rapid changes in flagellar rotation induced by external electric pulses.
The bacterial flagellar motor is the only molecular rotary machine found in living organisms, converting the protonmotive force, i.e., the membrane voltage and proton gradients across the cell membrane, into the mechanical force of rotation (torque). We have developed a method for holding a bacterial cell at the tip of a glass micropipette and applying electric pulses through the micropipette. This method has enabled us to observe the dynamical responses of flagellar rotation to electric pulses that change the membrane voltage transiently and repeatedly. We have observed that acceleration and deceleration of motor rotation are induced by application of these electric pulses. The change in the rotation rate occurred within 5 ms after pulse application.
Cell Membrane↗
The role of electrogenic pump in Chara corallina.
The conductance, G, and the electromotive force, E, of the Chara membrane were determined accurately by using the current-clamp technique. The measurements at the final steady state of inhibitor poisoning give the conductance, g1, and the electromotive force, E1, of the passive ion conducting pathways. By knowing these values the conductance, g2, and the electromotive force, E2, of the electrogenic pump can be calculated from the measured G and E at each time during the progress of inhibitor poisoning. The local closed circuit current, i, which usually causes a hyperpolarization across the passive conducting pathways, can be calculated by using g1, g2, E1 and E2 thus determined. The values of g2 and i decrease monotonically to zero with the progress of poisoning, while E2 approaches E1 asymptotically after a transient hyperpolarization. During excitation i increases markedly. Such an increased inward current through the passive conducting pathways may help in accelerating the inactivation of the excitatory mechanism.
Action Potentials↗