Photomovement in Cyanophora paradoxa

Photomovement has been studied in the symbiontic association of the colorless flagellate, Cyanophora paradoxa Korschikoff with the cyanelles, Cyanocyta korschikoffiana. There is no phototactic orientation in this organism, but a photokinetic effect. In addition, the cells show a pronounced step-up photophobic response (however no or only a weak step-down response). The phobic response is mediated by a subset of the photosynthetic pigments located in the symbiontic cyanelles. It is linked to the noncyclic photosynthetic electron transport chain but it is independent of the photosynthetic generation of a proton gradient and the ATP synthesis linked to it.Abbreviations CCCP carbonyl cyanide m-chlorophenyl hydrazone - DBMIB 2,5-dibromo-3-methyl-6-isopropylbenzo quinone - DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea