FIG. 5.

Quantitative measurement of the chemotactic response of Silicibacter sp. strain TM1040 to pure compounds. Chemotaxis of TM1040 was assessed using the capillary assay with a subset of potential attractants discovered using the qualitative assay. Capillaries were filled with either buffer (as a control) or 2 μM (white bars) or 200 μM (black bars) attractant. The response factor was calculated by dividing the mean number of bacteria in attractant-filled capillaries by the mean number of bacteria in buffer-filled capillaries. DMSP and amino acids produced the strongest chemotactic response from TM1040. NAG, N-acetylglucosamine; Pro, propionate; AKG, α-ketoglutarate. The values shown are the means and standard deviations (n = 12).