Fortunately for spiders, millennia of evolution have made spiders so versatile. The proteins are structured like dumbbells, Dr. Rising explained: a long, unordered chain limited to each end by a lightning-like blob. In silk glands, these barbells are supposed to spontaneously pair at one end, creating V-shaped pairs that sway around in the dope.
To form the more stable structure required of solid silk, the spins need to be bonded together in a series, using the other ends of the bar. Jessica Garb, a spider silk researcher at the University of Massachusetts, Lowell, who was not involved in the study, said that seems to have happened under the influence of some chemical signals. As the spidroin sludge is extruded through an increasingly narrow labyrinth of ducts, the spider cells pump acid into the mixture, causing the free ends of the bar to stick together. The journey through these tapered tubes also pulls and presses the silk into its final form.
Dr. Malay and his colleagues found that this sculpture and self-assembly cannot happen if the liquid spiders are not dehydrated as they move through the spider’s anatomy.
Further experiments showed that salt causes proteins to quickly distance themselves from the fluids around them, like oil and vinegar in salad dressings. Cheryl Hayashi, a spider silk researcher at the American Museum of Natural History who was not involved in the study, said this allows the spins to interact more easily. Freshly thickened, the spidroins’ broth then self-formed into an increasingly tight structure.
The silk extrusion pipe sounds a bit cumbersome. It is extremely elegant from an engineer point of view, said Keiji Numata, a Riken scientist who led the study. Scientists can create super-hard polymers in the lab through force, forcing the materials together in ways they can’t. But with the right ingredients, under the right conditions, the spider silk recipe will essentially cook itself.
Researchers still don’t know enough about this process to fully reproduce it. There are also many ways to spin spider silk, different between species and even within the same spider, Dr. Garb said. Although silk may be best known for their role in web building, they can also be used to attract mates, protect eggs, or even help spiders roam in a bout. the breeze passed.
This research focuses on proteins found in scissor silk that act as a bungee cord for spiders dangling from their webs or ceilings. “But there are still a lot of things that nature has discovered that we don’t know yet,” said Dr. Hayashi.