Paper
1 May 1991 Picosecond time-resolved fluorescence spectroscopy of phytochrome and stentorin
Pill-Soon Song
Author Affiliations +
Proceedings Volume 1403, Laser Applications in Life Sciences; (1991) https://doi.org/10.1117/12.57324
Event: Laser Applications in Life Sciences, 1990, Moscow, Russian Federation
Abstract
Phytochrome is a tetrapyrrole chromoprotein. It serves as a sensitive photosensor for red lightmediated gene expression and other developmental/morphological responses in plants. In this paper photochemical dynamics of the phytochrome molecule have been described in terms of photoisomerization of the tetrapyrrole chromophore in its singlet excited state and subsequent thermal processes in the Pr Pfr phototransformation of phytochrome. Stentorin acts as the photosensor molecule in the ciliate Stentor coeruleus. This unicellular protozoan is most sensitive to red light (610-620 urn). Stentor also senses the direction of light propagation as evidenced by their light-avoiding and negative phototactic swimming behaviors. This aneural photosensory phenomenon is triggered by the photoreceptor stentorin. The possible involvement of a light-induced transient proton release from the photoreceptor as the primary mechanism of light-signal processing has been discussed on the basis of picosecond fluorescence decays and time-resolved fluorescence spectra of stentorin in solution. An initial sensory signal generated by the primary photoprocess of stentorin then triggers subsequent transduction steps that include calcium ion influx from the extracellular medium. Calcium ion influx from the extracellular medium to the cytosol causes the Stentor cell to reverse its ciliary beating and subsequently steer away from the light trap. II.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Pill-Soon Song "Picosecond time-resolved fluorescence spectroscopy of phytochrome and stentorin", Proc. SPIE 1403, Laser Applications in Life Sciences, (1 May 1991); https://doi.org/10.1117/12.57324
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KEYWORDS
Chromophores

Luminescence

Picosecond phenomena

Laser applications

Calcium

Time resolved spectroscopy

Molecules

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