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Euglena: The Photoreceptor System for Phototaxis *
Author(s) -
WOLKEN JEROME J.
Publication year - 1977
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1977.tb01004.x
Subject(s) - phototaxis , action spectrum , euglena , flavin group , biology , flavoprotein , biophysics , flagellum , euglena gracilis , photochemistry , botany , chloroplast , chemistry , biochemistry , bacteria , genetics , gene , enzyme
SYNOPSIS. The photoreceptor structures (eyespot‐paraflagellar body‐flagellum) for Euglena phototaxis were investigated by electron microscopy. The paraflagellar body—the photoreceptor—is a highly ordered crystalline lamellar structure. Optical diffraction of the electron micrographs and resulting filtered images of the paraflagellar body suggest that it is formed of rods in a helical arrangement. The action spectra for phototaxis, the in situ spectrum by microspectrophotometry of the paraflagellar body, and flavin analysis of the organism indicate that the photoreceptor molecule is a flavoprotein. The phototaxis action spectrum is similar to the spectrum for O 2 evolution and implies that similar molecules participate in the photo‐processes. As a result, a photochemical scheme is suggested in which a photo‐excited flavin and a cytochrome participate in the photoprocess. The photochemistry and photoreceptor structures for Euglena phototaxis are likened to a photoneuro sensory cell.