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Web-slinging professor seeks spider silk secret

by Tomoko Otake

Staff Writer

Shigeyoshi Osaki can read the minds of spiders. Or so you would think, if you see the way he handles the eight-legged arthropods.

Osaki, professor at the department of biomacromolecules at Nara Medical University in the city of Kashihara, Nara Prefecture, is also one of Japan’s foremost researchers on spiders, especially spider silk.

When The Japan Times recently visited his office, where he keeps hundreds of spiders for research, he achieved the astonishing feat of harvesting silk from a spider with several-centimeter-long legs — right on cue.

First, he brought in a few paper cups, each of which had a spider and a twig inside. He then explained that he has to keep each of these harmless spiders separately because, if they are kept together, they would eat each other.

The two kinds of spider species he keeps are Nephila pilipes, distinguished by long, thin legs and coming from Okinawa, and Argiope amoena, which are caught in Kochi and Wakayama prefectures and bear a black and yellow striped pattern on the abdomen.

As soon as Osaki removed a rubber band holding a plastic net over a paper cup, a big spider crawled out of the cup and moved about across the professor’s body. With great skill and care, Osaki managed to let the leggy creature stay on his right wrist, then nudged it onto a black cloth, using a twig.

And then, with the wizardry of a dolphin trainer or snake charmer, he gently tapped the creature’s rounded belly with the twig several times. “It will come out soon,” he whispered — and whoa! — a fine, silver fiber spun out of the spider’s belly as Osaki pulled the twig away from the cloth, just like the sticky strings you get when you remove chopsticks from a bowl of natto fermented beans.

“The key is to approach them with a mix of tough and gentle,” he said. “If you are too strict, you will upset them and they won’t produce the silk. They can also pretend that they are dead.”

The author of numerous scientific papers, books and essays on spiders, Osaki says he first got interested in the arachnid while researching the adhesiveness of stickers for a paper manufacturing company some 30 years ago. He found spiders, which spin sticky orb webs to catch prey, much more exciting than stickers, he recalls. But back then, no one had really done in-depth research on spider silk, he said.

“Most researchers were studying spiders from a biological perspective,” he said. “Their biggest motivation was to find a new species, because if they did, the species would be named after them.”

Osaki, on the other hand, became fascinated with the unique characteristics of spider silk. In particular, the so-called drag line, from which spiders dangle, is strong, expandable and not so sticky compared to other silk threads. He says the drag line’s exceptional strength is due to its two-filament structure, noting that it manifests the species’ great survival skills, which are born out of its 400-million-year evolutionary history.

Osaki has honed his spider-silk harvesting skills over the years — through trial and error. He said he once released a bunch of spiders on a big tree in his front yard, only to find that most died because they ate each other or fell prey to birds. Also because spider research was for a long time only a side project — his main specialty being the analysis of bio-polymers such as collagen — Osaki could only find time to go spider-watching on weekends and at night. He would always take his two sons along at night, because, if he had gone alone, he said, he “could have been mistaken for a pervert.”

The native of Hyogo Prefecture has also created and fine-tuned his own silk reeling device. While he declined to reveal how he harvests silk now, saying it’s “top secret,” he conceded that he still does it manually. His earlier versions were made out of manually-bent steel coat-hangers, which were then attached to motorized Chupa Chup toys — designed to spin lolly-pops in one’s mouth — bought at ¥100 shops.

After collecting spider silk through such labor-intensive efforts, he went on to test its strength, by tying the woven silk to a hammock and dangling from it himself. The experiment, boldly carried out on the university campus in 2006, was witnessed by journalists and reported nationwide, along with a photo of the suited, 65-kg Osaki clutching the ropes.

Osaki said that several projects have attempted, both in Japan and overseas, to mass-produce genetically engineered spider silk, either by breeding goats that produce spider silk through milk, or by injecting spiders’ DNA into the genomes of silkworms. But for now, these projects are in their research phases, and none of the players involved, who have invested vast amounts of money, have yet to start manufacturing bullet-proof jackets or run-free stockings out of spider silk. Osaki, meanwhile, said he would rather stick to exploring the untapped potential of natural spiders.

Last year, he created violin strings with silk he had harvested, with the conviction that his violin would sound different from others. During the visit, he kindly played the special violin. Unfortunately though, his musical skills were no match to his silk-harvesting expertise, so it was hard to tell whether his slightly off-key rendering of the melancholic Japanese classic song “Kojo no Tsuki” (“The Moon over the Ruined Castle”) proved the violin’s excellence over a conventionally-strung Stradivarius. But Osaki says a spectrum analysis of the spider silk-strung violin has shown it has “milder” sounds than regular violins with synthetic fibers. In fact, a professional violinist in Germany recently contacted him, begging to let her play the special instrument, Osaki says. While he has turned down the offer, saying more research and improvement is necessary, he is certain that this would cast a new light on spider silk.

“The violinist was very eager, saying she wants to come to Japan to sign a contract any minute,” he said. “But I need to refine it to a level at which I can let others play with confidence. So I must keep on playing myself … until I find out how to improve it.”