[ad_1]
Fortunately for spiders, millennia of evolution have made spidroins versatile. Proteins, Dr. Rising explained, are structured like rockers: a long messy rope covered at each end by a bolt-like blob. In the silk glands, these rockers are thought to naturally mate at one end, creating V-shaped duets that move into the drug.
To form the more stable architecture required for solid silk, the spidroins must join in chains, using the other ends of the rockers. This appears to be happening under the influence of a couple of chemical signals, said Jessica Garb, a researcher on spider silk at the University of Massachusetts, Lowell, who was not involved in the study. As the spidroin slurry is extruded through a labyrinth of ever-narrowing conduits, the spider cells pump acid into the mixture, causing the free ends of the rockers to stick together. The journey through these tapered tubes also pulls and tightens the silk into its final shape.
Dr Malay and his colleagues found that this sculpture and self-assembly couldn’t happen if the liquid spidroins hadn’t been dehydrated as they moved through the spider’s anatomy.
Further experiments showed that the salts caused the proteins to quickly move away from the liquid around them, such as oil and vinegar in a salad dressing. This allows the sprouts to interact more easily, said Cheryl Hayashi, a researcher on spider silk at the American Museum of Natural History who was not involved in the study. As soon as it thickens, the sprout stew then forms into an increasingly fibrous structure.
The silk extrusion pipeline might seem a bit cumbersome. From an engineer perspective, though, it’s extraordinarily elegant, said Keiji Numata, a Riken scientist who led the study. Scientists can build super tough polymers in the lab through brute force, forcing materials to bond in ways they otherwise wouldn’t. But given the right ingredients, under the right conditions, the recipe which is spider silk essentially cooks itself.
Researchers still don’t know enough about this process to fully recreate it. There are also many ways to spin spider silk, which varies between species and even within the spider itself, Dr. Garb said. While silks may be best known for their role in building webs, they can also be used to attract mates, protect eggs, or even help wandering spiders attack a passage on a passing breeze.
This study focused on the proteins found in dragline silk, which acts as a bungee cord for spiders that dangle from their webs or ceilings. “But there is still a lot more that nature has discovered that we don’t know about,” said Dr. Hayashi.
Source link
