With strange intelligences, moving skin and flexible bodies powered by three hearts, octopuses can go to any mischief. Their camouflage skills can allow them to remain hidden as they stealthily explore their surroundings with noodle limbs, each with its own mind. With them, these sea aliens can reach out to taste you.
We can now have some idea of how this ability to touch and taste works.
As their hands stretch across the seabed, groping with their thousands of independently moving, finger-like shoots, it turns out that octopuses use independent taste sensors as well as unique sensory cells to capture a sensory map of their surroundings.
Molecular biologist Lena van Giessen and colleagues at Harvard University have identified these chemosensory cells ̵
These chemotactic cells, with thin branched ends, can signal continuously (toning firing), but they depend on whether they are close enough to touch, more like our tongues. Chemosensory cells can respond to a variety of tastes, including chemicals found in cephalopod ink and “warning” chemicals emitted by potentially toxic prey.
“It is extremely useful for the octopus to find prey hidden in cracks in the seabed or areas inaccessible to traditional sense organs,” molecular biologist Nicolas Belono told ScienceAlert.
Within the skin of the shoots, the team also found expected and more familiar mechanosensory cells with steeper branched edges. These cells are activated only at the beginning of the contact before the signal is depleted (phase firing).
This type of signaling allows octopuses to know whether they are touching inanimate objects (where the signal would stop in a stationary contact) or a twisting prey where the signal would fire again in response to the loss and recovery of contact.
“We find that octopuses explore their environment using stereotypical touch movements that are clearly modified by contact with different [molecules that trigger the chemotactile receptors], “the researchers explain in their report.
They learned these skills by observing animals, conducting tests, and looking at what proteins are expressed by genes in certain sucking cells. This method is called transcriptomics and allows researchers to see what the cell is doing by analyzing what proteins are actively used in it.
The team found that some of the chemotactic cells were strongly activated in response to fish and crab extract. But they suggest that in addition to detecting prey, this ability to touch can also cause a quick retreat in repulsive flavors that hint at danger. They also observe how octopus ink eliminates the taste of the limb.
“Our findings were surprising because water chemosensation has long been linked to remote water signaling by chemicals that dissolve in water,” Belono said. “Our study shows that the octopus and potentially other aquatic animals can also detect poorly soluble molecules depending on contact.”
Chemotactic receptor genes have been found in the three different types of octopuses the team studied, but University of California biologist Rebecca Tarvin, who was not involved in the study, explains that other cephalopods like squid do not seem to use their suckers to taste their environment. way.
“We are really interested in how this unique sensorimotor system has evolved in other cephalopods,” said Belono, explaining that there are many questions about its evolution, physiology and use that are now being explored.
While they carefully examined only a few genes associated with specialized taste cells, there are hints of a large number of cells in the rest of the genome, with nearly 100 sensation-related genes yet to be characterized.
Belono said the mini-brains in the octopus’ hands must have an exceptional ability to filter information from so many highly specialized receptors. This may help explain why two-thirds of the octopus’s neurons are in its hands.
So the octopus essentially has eight, brainy and dexterous tongues that allow them to taste food, semi-independent of their main body, in the dark depths of their oceanic homes. How much more delightfully strange can life become?
This study was published in Cage.