Chemokinesis in Rhodobacter sphaeroides is the result of a long term increase in the rate of flagellar rotation
Brown S., Poole PS., Jeziorska W., Armitage JP.
Rhodobacter sphaeroides responded to the addition of 1 mM pyruvate by an increase in the mean population swimming speed from 18.7 ± 0.6 μm s -1 to 29.9 ± 0.8 μm s -1 . Examination of the behaviour of free swimming populations of bacteria and individual cells, and individual cells tethered by anti-flagella antibody showed that the increase in mean population swimming speed is at least partly the result of individual cells swimming faster. This was caused by an increased flagellar rotation rate, rather than any significant change in flagellar geometry which might change the propulsive efficiency of the flagellum. Previous measurements had showed that there was no increase in the steady state electrochemical proton gradient (Δμ H+ ). This implies that the conductance of the flagellar motor or the structure coupling proton flow to rotational energy changed following pyruvate addition.