14 DAY TRIAL // A group of researchers from Germany recently managed to accomplish a feat worthy of the record book, when they designed and bred insects capable of reacting to light as if to smell. In their experiments, the investigators managed to genetically-modify a number of Drosophila (fruit fly) larvae, in a manner that allowed them to, in essence, smell blue light. What the team did was manipulate genes that are sensible to this type of photons, so that they responded by generating a feeling of smell in the larvae. When exposed to the blue light, larvae can either smell bananas, glue, or marzipan, depending on how the scientists tinkered with their genes. All of these odors are irresistible to the fruit fly larva.
The group worked on only one of the 28 olfactory neurons that Drosophila has. When this single one was activated, this particular perception became possible, they reports. In nature, fruit flies are not very willing to go into the light, and actually steer clear from it by as much as possible. The specialists, based in Bochum and Gottingen, managed to make the creatures immune to their fear of blue light. The investigation was conducted under the direction of professor Klemens Stortkuhl. Additional details of the experiments are published in the latest issue of the international scientific journal Frontiers in Neuroscience Behavior. The science team hopes that this line of investigation could provide them with more clues into how neural networks and pathways form, PhysOrg reports.
The larvae are only one millimeter in size, and yet the German team managed to manipulate their traits in such a way that its olfactory neurons became capable of producing a protein that reacts to blue light. Using a number of custom-made genetic markers, investigators are capable to determining and controlling which of the 28 olfactory neurons will become light-sensitive, and which will remain immune to the effects of blue light. The research group says that when light at a wavelength of 480 nanometers is shone on the larvae, the small creatures believe they are smelling odors, and act accordingly. If the smell they are conditioned to feel is repulsive, then they will have an aversion response, the scientists say.
The effects of blue light were not inferred from the actions of the larvae, but by measuring the transformation of the light-activated neurons via very thin electrodes. The full pathway of the electrical signals can be determined in this non-intrusive manner, which means that researchers can conduct their research on living organisms. Similar investigations will in the future be conducted on mature Drosophila flies, and then on mice, the team says.