Scientists in Japan have demonstrated a technique that essentially allows them to remotely control the movements of worms. By implanting light-sensitive proteins into the organisms, the team was able to make them move under green light and stop under UV.
Organisms need to be able to respond to different stimuli in their environment, such as light or chemicals, which helps them find food and avoid dangers. Hacking into this sensory system can allow us to create remote-controlled “cyborgs” – cockroaches, for instance, can be steered by electrically stimulating their antennae so they instinctively turn away from a perceived obstacle.
For the new study, scientists from Osaka Metropolitan University used proteins called opsins as the trigger. These proteins are sensitive to different wavelengths of light, and respond by sending out signals that can set off other neurological circuits that they’re connected to, a field known as optogenetics. Previous work with opsins has shown that they can be used to restore vision to blind mice, or modulate pain in response to light.
In this case, the team used them to directly control the movements of C. elegans, a tiny worm commonly used in lab studies. Two opsins were implanted into these worms – one, which originated in mosquitoes, was placed into sensory cells that cause the creatures to wriggle away from a stimulus, which here would be light. The second opsin, sourced from lampreys, is sensitive to UV light and was implanted into the worms’ motor neurons.
Together, this meant that the worms would begin moving when exposed to green light, and would stop completely under UV. The team tested the technique and found that it could work over and over again, indicating the proteins weren’t being destroyed with repeated exposure. That indicates the technique could be used to create optogenetic signaling systems that perform different functions under different colors of light.
“Both the mosquito and lamprey opsins we used are members of the G protein-coupled receptor (GPCR) family of receptors – which are used to sense various stimuli including smell, taste, hormones, and neurotransmitters – demonstrating that this system using light can be used to manipulate various GPCRs and their subsequent intracellular signaling and physiological responses,” said Professor Mitsumasa Koyanagi, lead author of the study.
It’s a little unclear exactly what applications this research could lead to, but the team says it’s a breakthrough in understanding the biology of these sensory systems, and could eventually lead to new drug discoveries.
The research was published in the journal PNAS.
Source: Osaka Metropolitan University