Figure 3. Measurement of the interaction of the bacterium with the surrounding LB agar in terms of the interaction force constant (K_bio).

The K_bio values, representing the interacting forces between bacterium and 0.2% LB-agar, were measured by oscillatory optical tweezers. In each group, about 20 measurements were performed and every single spot represents a measured K_bio value; the horizontal line marks the average of the group. Asterisk indicates that a statistically significant difference is observed between the paired strains (p<0.001 by t-test).