Temporal change of photophobic response of Euglena gracilis observed in a micro-aquarium chip

Abstract

The photophobic responses of motile micro-algae, Euglena gracilis, were investigated in a time course of several hours for a cell population confined in a microchip. Two types of experiments, i.e., whole area blue-light pulse illumination (A) and spatially patterned blue-light illumination (B), were alternatively repeated as ABAB... for the same cell population. We found that the cells changed their response motions in a time course of a couple of hours, and the cells acquired more effective responses for escaping from the blue-light illuminated area. Such single-cell-level motion analysis has not been investigated for a long-term temporal changes.