ACTION SPECTRA OF THE PHOTOPHOBIC RESPONSE OF BLUE AND RED FORMS OF Blepharisma japonicum

Abstract— When exposed, in the presence of molecular oxygen, to light intensities of the order of3–30 W m^-2, the ciliate Blepharisma japonicum changes its color from red to blue, because of the photooxidation of the photoreceptor pigment, blepharismin, to pxyblepharismin. Both red-and blue-pigmnentes cells show step-up photophobic responses. The action spectra f the light-dependent behaviour of the red and the blue form of Blepharisma have been determined; their structure is very similar to that the photosensing and phototransducing properties of blepharismin are maintained in its photooxidized form. oxyblepharismin.