FIG. 2.

The effects of starvation on the chemotactic response of Silicibacter sp. strain TM1040. The chemotaxis of unstarved versus starved cells to 200 μM methionine was measured using the capillary assay (Materials and Methods). Chemotaxis of starved cells to either methionine (black bars) or buffer lacking nutrient (white bars) is compared to the response of unstarved cells either to methionine (dense cross-hatched bars) or to the buffer lacking nutrient (sparse cross-hatched bars). The response factor, calculated by dividing the mean number of bacteria in methionine-filled capillaries by the mean number of bacteria in buffer-filled capillaries, is significantly increased in the starved cells (▪) compared to that in the unstarved cells (○). The values shown are the mean and standard deviation (n = 12).