Related Experiment Video
Updated: Aug 5, 2026

A Microfluidic Device for Quantifying Bacterial Chemotaxis in Stable Concentration Gradients
Published on: April 20, 2010
Effect of methionine on chemotaxis by Bacillus subtilis
Abstract:
Bacillus subtilis, like Escherichia coli and Salmonella typhimurium, carries out chemotaxis by modulating the relative frequency of smooth swimming and tumbling. Like these enteric bacteria, methionine auxotrophs starved for methionine show an abnormally long-period of smooth swimming after addition of attractant. This "hypersensitive" state requires an hour of starvation for its genesis, which can be hastened by including alanine, a strong attractant, in starvation medium. Susceptibility to repellent, which causes transient tumbling when added, if anything, increases slightly by starvation for methionine. The results are interpreted by postulating the existence of a methionine-derived structure that hastens recovery of attractant-stimulated bacteria back to normal.
Related Concept Videos
Chemotaxis and Direction of Cell Migration
Flagella and Motility in Bacteria
Chemotaxis in E. coli
Other Unique Bacteria

