Chemical Stimulation and Inhibition of Bacterial Motility Studied with a New Method.

Abstract

The motility of Proteus vulgaris X 19 was studied in a special chamber which permits prolonged and undisturbed observation of a group of bacteria under the influence of different chemical agents. Strongest inhibition was observed with thiol inhibitors of the mercaptide-forming type, particularly with p-chloro-mercuribenzoate. The oxidizing agent iodosobenzoate and particularly the alkylating-SH drugs, iodoacetamide and iodo-acetate, had a less marked inhibitory action. The specificity of the action of thiol inhibitors was confirmed in all cases by reversal of the inhibition with the thiol-reducing agents, glutathione and cysteine. KCN, Na azide, NaF and malonate had no action on the motility of P. vulgaris. Narcotics, such as chloral hydrate, barbital, phenobarbital and chloroform, inhibited motility only at high concns. In these cases recovery of motility could be obtained by simply washing in buffer or saline. Adenosine triphosphate [ATP] had a definite stimulating effect on the motility of P. vulgaris. It was found that, in bacteria inhibited w ith chloral hydrate, vibration and translatory movements started within periods of time which were 110 and 74% shorter with ATP than with saline or other organic or inorganic phosphates. The possible role of-SH groups and of ATP in bacterial locomotion is discussed.