Chemotaxis: the role of internal delays.
When exposed to certain chemoattractants, bacteria like Escherichia coli move up the concentration gradient[Delta inverted]c with a velocity kappa[delta inverted]c. Microscopically, E. coli moves at constant speed when it's flagellum is rotating counter-clockwise (ccw) and tumbles when the rotation is clockwise (cw). The lifetime of a ccw interval, tau+, is a function of the concentration c( t') experienced at earlier times. The corresponding response function was measured long ago by Berg and co-workers. We present here a detailed description of the motion taking place during one ccw interval. This gives an explicit formula relating the chemotactic coefficient kappa to the response function; the formula has some surprising features.
de Gennes
P-G
PG
Collège de France and Institut Curie, 11 rue P. et M. Curie, 75231 Cedex 05, Paris, France. pgg@curie.fr
D001683:Biological Clocks / Q000502:physiology*; D002633:Chemotaxis / Q000502:physiology*; D003198:Computer Simulation; D004926:Escherichia coli / Q000502:physiology*; D005407:Flagella / Q000502:physiology*; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000502:physiology*; D013997:Time Factors
D020409:Molecular Motor Proteins