EFFECTS OF IONOPHORES AND RUTHENIUM RED ON THE PHOTOTAXIS OF STENTOR COERULEUS AS MEASURED BY SIMPLE DEVICES

Abstract
Abstract— Two simple methods of phototaxis measurements have been applied to study the effects of ionophores on the negative phototactic response in Stentor coeruleus. The inhibitory effects of Ca2+‐ionophore (A23187), Ca2+‐blocking agent (Ruthenium Red), and K+ ‐ionophore (valinomycin) on photo‐taxis have been determined. Results suggest that the influx of Ca2+ plays a transducing role in the phototaxis of Stentor.