Team:ETHZ Basel

From 2010.igem.org

Project abstract

E. lemming

ETHZ Basel project goal is to control E. coli movements (chemotaxis) by means of light. In fact, we will change the chemotaxis pathway either by substituting the receptor with a light-sensitive one or by interfering with the kinase-phosphatase process with proteins whose binding and unbinding can be stimulated by pulses of light. In both ways, E. coli tumbling is induced or removed just by pressing a light switch and, as a consequence, a bacterium can be "driven" to a precise, pre-fixed point. Tumbling / directed flagellar movement rates are supervised by digital controller combined with image processing algorithms. This system enables to control single E. coli cells to move like mindless "Lemmings" in the direction they are forced to go.

Figure 1. Setup to control E. coli movements. An automatized microscope images the E. lemming. A connected computer system detects and tracks the cells. The direction of movement of the E. lemming is compared to the desired direction defined by the user, e.g. with a joystick. If the direction of movement deviates too much from the desired direction, the digital controller induces tumbling by sending a red light pulse. Otherwise, tumbling is repressed by sending a far-red light pulse.