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

Abstract

Conclusions

(1) The motility of Proteus vulgaris × 19 has been studied in a special chamber which permits prolonged and undisturbed observation of a group of bacteria under the influence of different chemical agents. (2) Strongest inhibition was observed with thiol inhibitors of the mercaptide-forming type, particularly with p-chloromer-curibenzoate. The oxidizing agent iodosoben-zoate and particularly the alkylating-SH drugs, iodoacetamide and iodoacetate, had aless 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. Potassium cyanide, sodium azide, sodium fluoride and malonate had no action on the motility of Proteus vulgaris. (3) Substances having a narcotic effect, such as chloral hydrate, barbital, phenobarbital and chloroform, inhibited motility only at high concentrations. In these cases recovery of motility could be obtained by simply washing in buffer or saline. (4) Adenosintriphosphate had a definite stimulating effect on the motility of Proteus vulgaris. It was found that in bacteria inhibited with 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.