It turns out that it is `` taste can be sensed '' with protein necessary to see things with eyes
A research team at the University of California, Santa Barbara has discovered that opsin, a protein that functions as a visual receptor, also functions as a taste receptor. The team's findings suggest that humans may have new taste receptors.
Functions of Opsins in Drosophila Taste
(PDF file)
Subtle flavors | EurekAlert! Science News
https://www.eurekalert.org/pub_releases/2020-04/uoc--sf040220.php
Below is a cross section of the human eyeball. Light focused by the iris passes through the lens and hits the retina . The visual cells present in the retina ' rhodopsin are present visual receptors called' that the rhodopsin alter the structure through stimulation of light, are processed in the brain transmitted to nerve becomes the change information So people can see things.
Rhodopsin is made up of a protein called ' opsin ' and a type of vitamin A called ' retinal '. Although opsin was said to react only with respect to the light of the stimulus until recently, to Craig Montell professor of the University of California, Santa Barbara Department of Biology is 2011, and the 'Drosophila is to feel the temperature change by the opsin' announcement want did.
Professor Montel and Nicole Leng, who has just completed his doctoral course, conducted an experiment to check the taste of the fly, thinking that the opsin molecule may also detect subtle chemical changes through the signal amplification process. .
Montel and his colleagues provided Drosophila melanogaster with two diets: 'sugar only' and 'sugar mixed with a small amount of aristolochic acid , which causes bitterness in humans.' Then, Drosophila melanogaster ignored bitter food and ate preferentially sugar-only food.
Next, when the Drosophila melanogaster was rearranged so that it did not normally express opsin, flies lacking one of the three types of opsin could not detect a small amount of aristolochic acid, and the sugar-only feed It turned out that both of them and the food containing aristolochic acid were eating the same amount.
However, when mixing a large amount of aristolochic acid with sugar, he said that he also avoided flies with defects in opsin, Professor Montell said, `` Originally opsin activates a receptor called TRPA1 channel , which causes a slight bitter taste. A large amount of aristolochic acid may directly activate the TRPA1 channel even in a fly with opsin abnormalities, '' he argued that opsin could detect levels of aristolochic acid that could not be sensed otherwise. I think it works as a protein.
According to Professor Montell, aristolochic acid also binds to opsin, just like retinal binds to opsin to form rhodopsin. In addition, it was confirmed that opsin chemically activated by aristolochic acid performs a molecular chain reaction that amplifies a small signal, as rhodopsin responds to even a slight light stimulus.
From the results of this experiment, Prof. Montell speculates that the role of opsin may be its original role as a chemical sensor. Taste refers to 'how to avoid chemicals that could be dangerous to you', and is one of the living functions of living organisms that are older than the ability to detect light. 'These results suggest that opsin is not limited to Drosophila, but may be an unknown taste receptor in mammals, including humans,' argued Professor Montell.
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