Genius and Species
IC biologists make big breakthroughs by studying small animals. By Doug McInnis
Slugs and slime are synonymous. While most people find the slime repulsive, Ithaca College biologist Andy Smith and his students think it is worthy of research.
Their focus is the slime produced by a slug local to the northeastern United States, a creature known scientifically as Arion subfuscus, or more commonly as the dusky slug. “If you touch their backs, they just start oozing slime,” says Smith, an associate professor of biology. “They’re really easy to study. You just irritate one of these slugs, and you get all the goo you want.”
While the slug’s productivity is helpful, what really interests Smith’s research team is the slime’s unusual properties. “As soon as you get it on your finger, it turns sticky and elastic,” explains Smith.
Smith thinks that products based on this slime could lead to much stronger, more flexible glues. He says that adhesives such as these that work on the wet, soft surfaces of the body could provide rapid and more thorough wound closure while minimizing scarring. The medical adhesives currently being used are limited in strength and compatibility with internal uses.
“Doctors are really interested in glues that can hold tissue together,” he says. “I’ve been focusing on the medical applications, but that doesn’t mean that’s the end of it. There’s no way to predict all the potential uses.”
The slug didn’t evolve its slime-producing properties to serve mankind. Smith thinks it functions as a defensive mechanism. “If you’re a small animal and you try to bite a slug and get a mouthful of this goo, there’s no way you are going to eat the whole thing,” he says. “Even a bird would have trouble with it. I’ve heard that licking the goo makes your tongue go numb. It’s probably secreting a neurotoxin.”
Smith and his students are isolating the chemical constituents of the goo to figure out which ones are important for commercial applications. They have found, for example, that the glue contains metal ions such as calcium, iron, and zinc. These metals are capable of binding strongly to different glue components, possibly linking them together into a solid network.
“When I took the metals out, I found that the glue wouldn’t set,” says Smith. That sent his team back to the drawing board to figure out which metals are necessary for the goo glue to work.
Smith’s research is an example of biomimetics, the science of looking for potentially useful substances in nature. Many researchers regard the natural world as fertile ground for the next generation of products, materials, and pharmaceuticals, because nature has had a long time to perfect itself.
“There are a lot of plants and organisms that produce materials that have useful properties,” Smith says. “So we look at them and try to figure out if we can copy them. Once that’s done, it’s up to the commercial scientists to turn basic research such as ours into products we can use.”
Understanding the Heart’s Machinery
Ithaca College pushes interdisciplinary research. One area in which that may pay off is the study of heart disease, where mysteries remain despite billions of dollars spent on research.
“What’s happened in science is that we know the easy stuff and now we’re working on the hard stuff,” says Jean Hardwick, associate professor of biology. She compares it to the job of an auto mechanic. “It used to be that if you knew how to rebuild the carburetor and fix the shocks, you were good. Now, cars are run by computers. You have to understand computers, electronics, and the complex integra-tion of the different systems of the car to repair the problem.” The same holds true for her research into how the nervous system regulates the heart.
“In science, everything interconnects,” she says. “ You have to be able to understand biology, chemistry, physics, and mathematics in order to approach the questions we’re trying to answer. If you’re going to understand the nervous system, you have to know something about all of these areas.”
Hardwick and her students use guinea pigs as test subjects to study how the nervous system adapts to chronic heart disease. Researchers know that in cases of chronic heart disease the sympathetic nervous system can go into overdrive, which can produce a potentially fatal erratic heartbeat.
“We’re studying the other side — the parasympathetic nervous system — which acts as a brake on the heart’s activity,” Hardwick says. “If you’re overdoing the body’s accelerator, and you can make the brake work better, then maybe you won’t crash. The hope is that what we find will be of use to clinical researchers so that they can take the next step. The more we understand about how the nervous system changes in response to chronic heart disease, the more easily they can develop therapies to specifically target the negative aspects of the disease while leaving the positive changes in place.”
On average, muskrats settle only about 200 meters from their birth spots and live their lives in a small area. But some muskrats travel up to 36 kilometers to find an adult home, says biologist Leann Kanda, who studies movement ecology — how animals move around the landscape.
“The question is why,” says Kanda, an assistant professor of biology, whose specialization is examining individual variation in movement within species. “What is it about that individual that makes it go 36 kilometers? Is that individual fundamentally different than the one that goes 200 meters?”
These questions are important when animal habitats are broken up by human development or natural disasters. The remaining area may be so small that some populations can’t survive. Knowing the space individuals of a species need helps land planners and ecologists create habitat corridors that can aid the movement of species between the disconnected areas of their natural habitat.
“Animals moving long versus short distances are probably moving through the landscape in different ways,” Kanda explains, “and they may have different ways in which they behave in the commun-ity and react to landscape changes and to people. For instance, it may be that only the most risk-taking individuals are willing to cross a road, but they are also the ones most likely to be observed at roads. We could be misled into thinking that this species is just fine with crossing roads because we only saw the risk-takers doing so. If you don’t know how animals actually move about in the wild, you don’t know what on the landscape needs to be preserved. If different individuals move in different ways, we need to know who moves which way and what other traits those individuals might have.”
In addition to her field work, Kanda is also trying to determine if there is a genetic component to behavior that can be passed on from generation to generation. She is running a parallel study with dwarf hamsters confined in a laboratory setting. Hamsters are a good model to study because they have short life cycles, and females can get pregnant two to three months after they are born. Although Kanda can’tobserve how the hamsters move around in the wild, she can see how they move around the lab and breed them to learn if the tendency to roam or stay at home is heritable.
“Particular personalities may be favored in a given population,” Kanda hypothesizes. “If suites of behavior are heritable, then they can be shaped by evolution.”