Deadly Venoms, Tougher-than-Steel Webs

04/24/2019
By Geoffrey Douglas

Jessica Garb’s fascination with spiders took root in her undergraduate days at Cornell, in a course on spider biology. She was captivated by the unique characteristics of spiders, one of the most species-rich creatures on the planet (there are more than 48,000).

Some spiders are masters of disguise. Some can live for up to 30 years. Others weave threads stronger than materials in a bulletproof vest.

“I learned how truly amazing spiders are,” says Garb, now an associate professor of biological sciences at UMass Lowell. “They’re such a diverse group of species, with so many different behaviors. You have the crab spider, which camouflages itself as a flower, and the peacock spider, where the male flashes its colors and dances to lure a mate. And they do amazing things with their silks. It just really fascinated me.”

More than 20 years later, the fascination lives on. When she came to UMass Lowell 10 years ago, Garb established her spider lab, housed on the sixth floor of Olsen Hall. In the lab, Garb and her research team are focusing their efforts on two particular spider species: the Darwin’s bark spider, native to Madagascar, whose web is tougher than steel and can extend long distances without breaking, and the infamous black widow, common in the southern U.S., whose potent venom is composed of a unique set of toxins that pose an “evolutionary mystery.”

The black widow’s venom, Garb says, can “make people very sick” — typically by overwhelming the nervous system, causing severe pain — but generally isn’t lethal. The challenge, she says, is to determine the molecular composition of the venom, through a painstaking study of its genome, to better understand how it evolved. The project, funded in part by a grant from the National Institutes of Health, compares venom from the black widow with that of other closely related but less hazardous species, such as the common house spider, to isolate and identify the particular toxins that account for the pain and sickness that the widow’s bite can cause.

The results of the project will hopefully be applied to the development of improved anti-venoms, as well as beneficial drug compounds derived from the venom itself, Garb says. This practice is already proving effective with other species. For instance, venom from the Israeli yellow scorpion, commonly known as the death - stalker scorpion, has recently received limited approval for the treatment of brain cancer, while other venoms have been used in drugs to combat chronic pain, certain blood conditions and other ailments.

“It’s an area that’s only going to grow,” Garb says.

But for all the wonders of the black widow’s venom — and the almost mythic status of the widow itself — the Darwin’s bark spider may be even more remarkable, and at least as promising in what it offers the rest of us. One of the silks spun by the species, so-called dragline silk, is “among the toughest materials in nature,” Garb says. Double the toughness of any other known spider silk, it is 10 times tougher than Kevlar body armor, although it weighs far less, and can be stretched long distances without breaking.

The spider, a native of the Madagascar rain forests that was discovered just 10 years ago, also constructs the largest orb webs ever recorded, sometimes stretching the full width of rivers.

So what is it about the Darwin’s bark spider silks, molecularly speaking, that give them such extraordinary properties? That’s the puzzle that Garb’s lab, armed with a $335,168 grant from the National Science Foundation and working in collaboration with two other universities, is tasked with solving. “This particular gene is fairly new to researchers, so there’s been very little study of it,” says Winny Rojas-Velez, Garb’s undergraduate research assistant. “We kind of have to piece things together as we go.” One method used to do this, she explains, involves the creation of a polymerase chain reaction (PCR), activated by a single strand of DNA serving as a primer. This process allows copies of a DNA sequence to be amplified many times, thus generating more copies of the same segment to target for study.

“It’s a trial-and-error process,” says Rojas-Velez, who is a pre-med student. “It’s the same approach people take to researching [possible] medicines. It’s really fascinating, and it’s given me a strong foundation in research.”

Graduate student Molly Dawson, another member of the Garb team at work on researching the silk of the Darwin’s bark spider, approaches the work from a different angle. Her challenge, she says, is through bioinformatics: analyze the properties of the spider’s silk “on a genomic level through RNA sequencing,” then compare it to that of other known species to determine what makes it unique.

The work, she says, is “probably two or three years” from being complete. Once finished, the team’s findings will likely be published in a scientific journal.

“It’s so cool,” says Dawson, “that there’s this super-tough silk out there, the toughest biomaterial currently known, and I get to be one of the people studying it. There are not many other people who can claim that.”

The commercial payoff, the team members agree, could be enormous. Already, says Garb, several companies are looking into the potential of spidersilk-derived products: parkas, sneakers, sportswear, accessories. But the potential, she says, extends far beyond that to all manner of durable protective wear, including helmets and body armor, as well as bandages, sutures, prosthetics and other medical provisions.

In Michigan, Kraig Biocraft Laboratories, which describes itself as a developer of “what many consider the holy grail of materials science: a practical and cost-effective technology for producing recombinant spider-silk-based fibers on an industrial scale,” won a $1 million contract with the U.S. Army to develop a super-durable spider-silk fiber that can be woven into protective clothing. “We are moving rapidly to commercialize our spider silk technology, which we believe will have a significant impact on the global textiles industry,” the company states on its website.

Spider silk may open up new roads to collaboration with other UML researchers. Garb says she is in discussion with a plastics engineering faculty member who is interested in developing new materials from spider silk.

In the lab, Garb and her team tend to numerous other spider species: golden silk orb weaver spiders, a wolf spider, bark spiders and even a tarantula affectionately named “Rocky.” Some are used to test research protocols, some are for teaching, and others are used for community education, which is a requirement of the NSF grant. As part of the outreach efforts, Garb has done presentations at the Lowell National Historical Park and has worked with the Tsongas Industrial History Center’s summer camp programs.

So how much more can we learn from spiders? As researchers continue to unlock the remarkable properties of spiders, the arachnids’ web of influence will continue to grow, in the community, in the lab, in the commercial marketplace — and in our lives.