New research conducted by Nathalie Hoang and a team of researchers has been published in the journal of the Public Library of Science. This study has shown that photoreceptors called cryptochromes in humans respond to blue light in much the same way that cryptochromes in plants do. While many of our cryptochromes are found in the retina of the eye, they can also be found in other tissues found near the surface of our bodies. The implication is that they must have a purpose in absorbing and responding to light, but exactly what their functions are is currently unknown. Preliminary findings suggest that these sensors may regulate our sleep cycle, also called our circadian rhythm.
The Author sums up the findings of her paper with these words:
Vision in animals is generally associated with light-sensitive rhodopsin pigments located in the eyes. However, animals ranging from flies to humans also possess ancient visual receptors known as cryptochromes in multiple cell types. In this work, we study the mechanism of light sensing in two representative animal cryptochromes: a light-sensitive Drosophila cryptochrome (Dmcry) and a presumed light-insensitive mammalian cryptochrome from humans (Hscry1). We expressed recombinant cryptochromes to high levels in living cells, irradiated the cells with blue light, and analyzed the proteins’ response to irradiation with electron paramagnetic resonance and fluorescence spectroscopic techniques. Photoreduction of protein-bound oxidized FAD cofactor to its radical form emerged as the primary cryptochrome photoreaction in living cells, and was correlated with a light-sensitive biological response in whole organisms. These results indicate that both Dmcry and Hscry1 are capable of undergoing similar light-driven reactions and suggest the possibility of an as-yet unknown photo-perception role for human cryptochromes in tissues exposed to light.
I don’t want to put words in the mouths of the researchers here, but basically it seems they are saying that our bodies react to light, or, as this particular study shows, blue light, though this particular research doesn’t show exactly how. Much of light and color therapy has long worked on this assumption, deriving its basis from a mixture of anecdotal observation and clinical testing and research. We are all very interested in seeing what this type of research will yet uncover about the way our bodies interact with light.
The report can be found on PLoS’s website here.
An article discussing the high points of the study can be found at ScienceDaily.com here.