Studies on the Mechanism of Arginine-Activated Motility in a Pseudomonas Strain

Abstract

A strain of Pseudomonas whose motility could be activated under anaerobic conditions by arginine was shown to decompose arginine to ornithine by enzymic reactions involving citrulline and adenosine phosphates. The enzymes were readily separable from the particulate cell fractions and were not associated with the external flagellar apparatus. Citrulline also activated anaerobic motility but only after a period of pre-aeration or subsequent to its aerobic intracellular synthesis from ornithine. Permeability experiments suggested strongly that the cells of the pseudomonad were more permeable to arginine and citrulline under aerobic than anaerobic conditions. The promotion of motility by citrulline and the dependence of arginine-activated motility on the activity of the arginine dihydrolase system indicate that arginine acts as a direct source of energy for motility.