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A Method for Extracting Pigments from Squid Doryteuthis pealeii
Published on: November 9, 2016
PIGMENTS OF THE RETINA : II. SEA ROBIN, SEA BASS, AND SCUP
1Woods Hole Oceanographic Institution, Woods Hole, and the Biological Laboratories of Harvard University, Cambridge.
The Journal of General Physiology
|October 30, 2009
Summary
Fish visual purple is spectroscopically similar to frog visual purple, with shared interactions with vitamin A and retinene. Sea robin retinas contain a pH-sensitive visual yellow that forms an indicator, not vitamin A or visual purple, in extreme pH conditions.
Area of Science:
- Biochemistry
- Vision Science
- Comparative Physiology
Background:
- Visual purple (rhodopsin) is a key photopigment in vertebrate vision.
- Understanding the properties of visual purple and its related compounds is crucial for vision research.
- Previous studies have established the role of vitamin A and retinene in the visual cycle of frogs.
Purpose of the Study:
- To spectroscopically compare visual purple from marine fish (sea robin, sea bass, scup) with that of frogs.
- To investigate the behavior of visual yellow in sea robin retinas under varying pH conditions.
- To identify compounds present in the fish pigment epithelium and choroid.
Main Methods:
- Spectroscopic analysis of visual purple from sea robin, sea bass, and scup.
- pH-dependent chemical assays on sea robin retinal visual yellow.
- Biochemical analysis of the combined pigment epithelium and choroid layer.
Main Results:
- Visual purple from sea robin, sea bass, and scup exhibited spectroscopic similarity to frog visual purple.
- The interrelations of fish visual purple with vitamin A and retinene mirrored those found in frogs.
- Sea robin visual yellow irreversibly converted to a pH indicator in strong acids or alkaline solutions (pH > 11).
- This indicator form did not yield vitamin A or visual purple, unlike neutral visual yellow.
- Ammoniacal conditions accelerated the reversion of visual yellow to visual purple.
- Vitamin A, flavine, and an unidentified xanthophyll were detected in the fish pigment epithelium and choroid.
Conclusions:
- Fish visual purple shares fundamental spectroscopic and biochemical properties with its amphibian counterpart.
- The pH sensitivity of visual yellow in fish retinas suggests unique regulatory mechanisms in their visual cycle.
- The presence of vitamin A, flavine, and xanthophyll highlights the complex biochemical composition of the fish retinal pigment epithelium and choroid.
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