Motility and Flagellum Synthesis in Halobacillus halophilus Are Chloride Dependent

The motility of Halobacillus halophilus as observed on swarm agar plates was strictly dependent on the chloride concentration. Cl(−) was apparently not used as the coupling ion for flagellar rotation. Cells grown in the absence of chloride were devoid of flagella, but flagellation was restored upon the addition of chloride. These experiments indicate that chloride is involved in synthesis of flagella in H. halophilus.