A new research says that a tiny roundworm has a better light-detecting cell that is 50 times more efficient than human eyes.
This follows the discovery of a new type of photoreceptor in nematodes called as LITE-1. In fact, the new one is a taste receptor of the nematodes, the eyeless millimeter-long roundworms.
The discovery has raised curiosity levels on LITE-1 as a taste receptor that also proved capable of receiving light implying that molecules can absorb light, which was unimaginable before.
Unique Animal Study
What makes the research unique is that it announced the third photoreceptor in animals. The other two being — opsins and cryptochromes.
The genetic code of LITE-1 also revealed that it was extremely different from the photoreceptors found in plants, animals and microbes. The new findings have been published in the journal Cell.
"LITE-1 actually comes from a family of taste receptor proteins first discovered in insects," said lead researcher Shawn Xu from the University of Michigan.
Calling the new research an entry point, Xu exuded the optimism that LITE-1 would prove useful for scientists in a number of ways.
LITE-1 was traced in a family of taste receptors that send taste signals to the brain. One pertinent point about LITE-1, according to Xu, is that it is not the same taste receptor as in mammals.
LITE-1 makes a new stride as only two types of photoreceptors have been acknowledged so far — cryptochromes and opsins. The opsin in the human eye is Rhodopsin and the light-absorbing chromophore of vitamin A or retina is an additional support.
High-Efficiency Photoreceptors
Studies at Xu's lab in 2008 showed that nematodes would move away from light. In fact, the new research has unveiled the real secret behind it. The study shows that LITE-1 can directly absorb light and is no intermediary.
Xu noted that LITE-1 is unusual with its ability to absorb both UV-A and UV-B light better than opsins and cryptochromes. LITE-1's processes are also different as it absorbs light directly.
Also, in the human eye, if photoreceptors are broken the chromophore will still retain some functionality. But in LITE-1, denaturing completely stops the ability to absorb light. The research also found LITE-1 protein carries amino acid tryptophan as a critical aid boosting the visibility function.
Ancillary Uses For LITE-1
Now researchers are looking to use LITE-1 for applications like sunscreen to capture harmful rays better than the creams in the market.
Triggering light sensitivity in new types of cells is another use. The researchers have already modified a nonlight-sensitive protein in the same family GUR-3 and made it react to ultraviolet light.
