Squids have long been a source of interest to people, giving way to myth, superstition and myth. And no wonder – their strange appearance and strange experience, their mastery of the open ocean can surprise those who see them.
Myths of the second side, squids continue to haunt people today – people like UC Santa Barbara professor Daniel Morse – for the same reasons, albeit more scientific. Having evolved for hundreds of millions of years of hunting, communicating, escaping predators and breeding in the vast expanses, often without the character of open water, squids have developed some of the most solemn skins in the animal kingdom.
“For centuries, people have been amazed at the ability of squids to change the color and patterns of their skin – which they do beautifully – for camoflage and underwater communication, marking each other and your species. other abstention, or as an attraction for courtship and other types of symptoms, “said Morse, Distinguished Professor of Biochemistry and Molecular Genetics.
Like their cephalopod cousins the octopus and cuttlefish, squids have pigment-filled cells called chromatophores that expand until they are exposed to light, resulting in different shapes of pigmentary color. Particularly interesting to Morse, however, is the ability of the squids to move and blink, revealing different colors and breaking light over their skin. It is an effect that is thought to resemble the bright light of the high ocean – the only feature in a bare seascape. By understanding how squids are going to run themselves into even the simplest of situations – or stand out – it may be possible to make products with the same light weight training properties. for a number of applications.
Morse has been working to solve the mystery of squid skin for the past decade, and with the support of the Army Investigation Office and research published in the journal Applied Physics Letters, he and co – author Esther Taxon come even closer to unraveling the complex mechanisms that underlie squid skin.
Fine equipment
“What we have found is that the squid is not only able to illuminate the color of the visible light, but also its brightness,” said Morse. Research to date has confirmed that some proteins called reflectins were responsible for instability, but the ability of the reflector to adjust the brightness of the reflected light remained a mystery, he said.
Previous research by Morse had found structures and ways in which iridocytes – light-reflecting cells – in the skin of the opalescent shore (Doryteuthis opalescens) can accept almost all colors of the rainbow. It occurs with the cell membrane, where it folds into nanoscale box-like structures called lamellae, forming small grooves outside a subwoofer.
“These tiny structures are similar to the ones we see on the side of a compact disc carving,” Morse said. The color displayed depends on the width of the groove, which is in line with specific light waves (colors). In squid iridocytes, these lamellae have the added feature of being able to shape, expand and narrow down these grooves through well-manipulated “osmotic motor” actions guided by condensing or dispersing reflectin proteins. apart within the lamellae.
While material systems containing reflectin proteins were able to estimate the iridecent color changes that squid was capable of, there were constant attempts to reproduce the brightness-enhancing ability of these reflections, which according to the researchers, who reasoned that something had to be linked to the appearance in scabies skin, increasing their effect.
That was the real member orbiting the reflections – the lamellae, the same structures that were responsible for the grooves that shone light into the proportional colors.
“Evolution has optimized not only the color tuning, but the brightness brightness using the same material, the same protein and the same equipment,” Morse said.
Light at the speed of thought
It all starts with a signal, a neuronal blow from the squid’s brain.
“Reflectins are usually strongly cut,” Morse said of the iridescent proteins, which, when not applied, look like a string of beads. The same cost means they overlap.
But that can change when a neural signal causes the reflectins to bind phosphate groups with a negative charge that neutralizes the positive charge. Without the reaction keeping the proteins in their disorganized state they fold and attract each other, accumulating in fewer to larger aggregates in the lamellae.
These clusters exert an osmotic pressure on the lamellae, a semipermeable ball built to withstand just as much pressure as the clustered clusters before releasing water outside the cell.
“Water gets out of the box-like structure, and that lowers the box so that the thickness in the width between the beats is reduced, which is like bringing tight disc grooves closer together, “Morse explained.” So the reflected light can gradually shift from red to green to blue. “
At the same time, the collapse of the organs straightens the reflections, causing an increase in their remodeling schedule, increasing brightness. Osmotic pressure, the motor that drives these devices of optical properties, binds the lamellae tightly to the reflectins in a high calibrated relationship that gives the best output (color and brightness) to the output. -in (neural signal). Sweep away the neural signal and the physics will go back, Morse said.
“It is a very subtle, indirect way of changing color and brightness by controlling the physical behavior of what is known as colligative properties – the osmotic pressure, which is not immediately apparent, but reveals -the complexity of the evolutionary process, thousands of years of mutation. and natural selections that have strengthened and optimized these processes together. “
Filmean tana Tunable-Brightness
The presence of a membrane may be the crucial link for the development of bioinspired thin films with the optical tuning capability of the opalescent shoreline.
“This discovery has an interesting impact on the key role of the membrane in tuning reflective brightness for future product design and buihybrid coating with tunable optical properties that soldiers and their equipment may have. defense, “said Stephanie McElhinny, program manager at the Office of Army Investigation, an element of the U.S. Army Capability Development Command ‘s Weapons Research Laboratory.
According to the researchers, “This reflective, efficient link of reflectin of its osmotic amplifier is very similar to the connection that matches activator-transducer-amplifier networks in electronic, magnetic, mechanical and mechanical systems. sound with a good engine. ” In this case the actuator would be the neuronal signal, while the reflectins act as transducers and the osmotically controlled organs serve as the amplifiers.
“Without that membrane around the reflexes, there is no change in the brightness of these artificial thin films,” said Morse, who is collaborating with engineering colleagues to study it. the potential for a thin film that is more skin-like. “If we want to capture biological power, we need to introduce some sort of organ-like circulation to allow back-up clearance to be clear.”
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