Histidine starvation and adenosine 5'-triphosphate depletion in chemotaxis of Salmonella typhimurium.

摘要

Starvation for histidine prevented tumbling in Salmonella typhimurium hisF auxotrophs, including constantly tumbling strains with an additional mutation in cheB or cheZ. However, histidine-starved cheZs hisF strains were not defective in flagellar function or the tumbling mechanism since freshly starved auxotrophs tumbled in response to a variety of repellents. Tumbling in histidine-starved S. typhimurium could be restored in 13 s by addition of adenine or in 4 min by addition of histidine. Chloramphenicol did not prevent restoration of tumbling by these substances. Assays of adenosine 5'-triphosphate were performed based upon previous demonstration of adenine depletion in hisF auxotrophs starved for histidine. The adenosine 5'-triphosphate concentration dropped rapidly during the course of starvation, falling to less than 5% of the initial level as the cells ceased tumbling entirely. The change to smooth motility was prevented by 2-thiazolealanine, which inhibits phosphoribosyltransferase, thereby preventing adenine depletion during histidine starvation. These results suggest that an adenosine 5'-triphosphate deficiency was responsible for the change in tumbling frequency.