Effect of cell size on bacterial motion in micropillars arrays*

Although there has been tremendous focus on the fundamental principles of bacterial cell body morphology, little is known about how this morphology couples bacterial dynamics to their local environment. We have focused on investigating bacterial dynamics with regard to changes in bacterial size in a fixed background environment of micro-pillar arrays. Utilizing our high throughput tracking and image analysis tools, we are able to better quantify changes in bacterial motion while they interact with the micro-pillar environment. Our findings highlight that non-tumble E. coli mutants display bimodal transportation behavior that is bacterial size dependent. For small bacteria (4 $\mu$m), behavior becomes more tortuous that correlates with circular motion around pillars, while larger (7 $\mu$m) bacteria display high diffusivity, rarely interacting with pillars. To further investigate the role of bacterial size with micro-pillar environments we have studied bacterial motion through multiple pillar size arrays in order to elucidate mechanisms that control bacterial locomotion and its coupling to cell body size.