Opsin protein was discovered in the late 1800s. Scientists have discovered the light-sensing role of rhodopsia in the form of an opsin and a vitamin A. Rodopsin has become the most studied sensory receptor after discovery. Until recently, scientists thought that the rhodopsin protein family was involved only in light intake. In 2011, the work of Craig Montell and his team revealed that opsin was also used to detect small temperature changes in fruit flies. Animals have many types of sensory proteins that respond to stimuli from the environment. High temperatures are required to activate some of these sensory proteins. However, rhodopines can react to very subtle changes or very low stimuli, as well as in very low light conditions. Montell and his team, who have been working on ops for a long time, decided to study the taste receptors of fruit flies. Researchers used aristolohic acid, a toxic and bitter compound found in some plants to study taste receptors. High concentrations of aristolohic acid enable the protein to be activated by opening a channel called TRPA1, which allows the flies to enter calcium and sodium directly into the cells of taste neurons. Activating this protein results in a bitter taste that animals avoid. The study of fruit flies on taste receptors shows that flies avoid even low-concentration aristolohic acid, rather than opening channels directly. Montell and Nicole Leung at the University of California think that opsin molecules can also be used to detect weak chemical signals through a signal amplification process. Scientists conducted another study on fruit flies to test these theories. Opsins can detect chemical compounds regardless of their quantity The researchers gave fruit flies normal sugar and diluted aristolohic acid added sugar. Flies surprisingly did not opt for sugar mixed with dilute aristolohic acid. Instead, all the flies turned to pure sugar. Scientists grew mutated flies that were prevented from synthesizing opsin proteins into the experiment to understand the connection of this selection to opsin protein. Flies that were grown mutated were unable to detect dilute acid concentrations. Flies also ate the same amount of diluted aristolohic acid mixed sugar with pure sugar. Flies that were prevented from developing different opsin proteins were susceptible to high concentrations of aristolohic acid, although they could not recognize the sugar, which was dilute aristolohic acid. In this way, the researchers found that the aristolohic acid binds to the region of light-activated rhodopsin. Rhodopsin, which opened in very dim light, then initiated a molecular process that amplified weak signals. This process enabled detection of compound concentrations that would not be sufficient to trigger a response in the sensory neurons of flies. Montell believes that chemical communication may have the original role of opsin proteins. Montell said that the intake of chemicals for life is a more basic requirement than light intake. The scientist, who is an expert in opsins, stated that knowing what to eat and what chemicals to avoid is an older survival function than light sensing. This work is not the only one Craig Montell did in the field of opsin. Finding that opsin reacted to low temperature changes in 2011, Montell found that opsin protein also played a role in the hearing ability of flies. Stating that opsins, which play a role in seeing, tasting and hearing, may also have an effect on other senses, Montell added that it is still exciting to discover new things about opsin discovered in 1870.
