Inhibitio of flagellar coordination in Spirillum volutans.

The motility of Spirillum volutans is caused by the rotation of each polar flagellar fascicle in a direction opposite to that of the more slowly rotating cell. Both flagella form cones of revolution oriented in the same direction. When the cell reverses its motion, both fascicles simultaneously reverse their rotation and also the orientation of their cones of revolution, with the tail fascicle becoming the head and vice versa. Chloral hydrate and phenol were found to cause uncoordination, with both fascicles becoming the head type; MgSO(4), Mg(NO(3))(2), NiSO(4), NiCl(2), CuSO(4), and CuCl(2) also caused uncoordination, with both fascicles becoming the tail type. In all cases, the flagellar fascicles remained highly active but the cells were motionless because of the opposing propulsion; the rotation of the fascicles was in a constant direction without reversal. Uncoordinated states could be maintained for 30 to 60 min. Neutralization of the dual-tail flagellation caused by NiSO(4) could be accomplished with chloral hydrate. At the null point, the flagellar orientation was intermediate between head and tail; the fascicles continually reversed direction of rotation, and, now coordinated, caused the cells to move back and forth. Higher concentrations of chloral hydrate completely overcame the effect of NiSO(4) and caused dual-head flagellation. Optimal concentrations of test compounds were determined with the use of pure cultures and a reproducible growth medium.