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Updated: Aug 5, 2026

Preparation of Living Isolated Vertebrate Photoreceptor Cells for Fluorescence Imaging
Published on: June 22, 2011
In vivo photocycle of the Euglena gracilis photoreceptor
L Barsanti1, V Passarelli, P L Walne
1Istituto di Biofisica, CNR, Pisa, Italy.
Abstract:
We present the light-induced photocycle of the paraflagellar swelling of Euglena gracilis. The kinetics of this process was reconstructed by sampling its fluorescence emission and switching the excitation light from 365 nm to 436 nm. Stable intermediates in the photocycle were manifested. The measured millisecond resolution kinetics best fits a Michaelis-Menten equation. The data provide strong evidence that the paraflagellar swelling, a three-dimensional natural crystal of a light-detecting protein, is the true Euglena photoreceptor.
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