Effects of porphyrins on encystment and excystment in ciliated protozoan Colpoda sp.

Abstract

SUMMARY Excystment of Colpoda sp. was found to be triggered by a brownish fraction obtained by high performance liquid chromatography (HPLC) of cereal infusion that was expected to contain porphyrins. A commercial porphyrin, chlorophyllin (coppered, sodium salt) induced excystment and prevented encystment, while protoporphyrin IX without metal, protoporphyrin IX bound to zinc, and riboflavin did not have any excystmentinducing effect. These results suggest that the porphyrins contained in cereal leaves might trigger excystment and prevent encystment. Greencolored chlorophyllin is expected to be useful as a molecular probe to visualize and isolate receptors for triggering the encystment and excystment proc