Researchers from the University of Würzburg and Bielefeld (Germany) have discovered a “family” of light-sensitive molecules (photoreceptors) never seen before in algae, in both unicellular algae like Chlamydomonas reinhardtii, and in multi-cellular algae like Volvox carteri. The name 2c-Cyclop (abbreviation of “Two Component Cyclase Opsin”) has been given to these photoreceptors, which can be considered as a kind of rudimentary eye.
As reported in the scientific journal BMC Biology, these photoreceptors have unexpected properties: they are light-inhibited, not light-activated, and follow several “mechanisms” that are also found in the human eye. According to the German researchers, the discovery of 2c-Clops will provide new “tools” in the field of optogenetics, an innovative branch of biology that studies the possibility of activating or deactivating specific DNA traits (in appropriately treated cells) using simple light impulses.
Professor Georg Nagel, head of the study published in BMC Biology, is considered one of the pioneers of optogenetics, together with the biophysicist Peter Hegemann, from the Humboldt University in Berlin, and other scientists. It all began around fifteen years ago with studies on algae, when researchers realised that certain proteins in these plant organisms, called opsins, were able to react to light and could be transferred inside nerve cells (even human ones), using a genetic engineering technique. Since opsins favour the spread of the electrical impulses typical of nerve cells, but are also light-sensitive, the researchers were able to “direct” their activity using different types of light impulses. This meant that the cell mechanisms of neurons that were previously difficult to decipher could be studied from the inside: especially those involved in the functioning and malfunctioning of the cells that play a part in diseases such as Parkinson’s, autism, anxiety and depression.
The 2c-Clops also belong to the opsin family, but use different biochemical mechanisms from those of other molecules that had been discovered up till now in algae. And, it is for this exact reason, that they can open new avenues in the field of optogenetics.