by Anne Downey '95G
Illustrations by Harriet Russell
In this issue:Have a Drink
Have a Drink
Several years ago, Robert Kenefick, an associate professor of exercise science at UNH, made a curious observation after an arduous ice climbing trip in New Hampshire's Crawford Notch: Although he and his friends had gotten some serious exercise, no one was thirsty.
"We were out for about eight hours, and on the hike back, people were emptying their full water bottles because they didn't want to carry them," he remembers. "After a strenuous day, no one had had anything to drink."
Kenefick came down off the mountain with a hypothesis—that cold weather alters our perception of thirst—and put it to the test. In an "environmental chamber," a small room equipped with temperature and humidity controls, 12 male volunteers in their mid-30s performed a series of physical tests on a treadmill. Participants exercised at moderate intensity under different levels of hydration: dehydrated and normally hydrated in both cold and room temperatures.
Participants were tested afterwards for skin and body temperature, blood composition and cardiovascular function such as heart rate and output. He also asked the volunteers how thirsty they were.
The study confirmed what he suspected: in the cold, perception of thirst goes down. Kenefick began new tests to figure out why. By measuring hormones and blood flow to the skin, Kenefick discovered the cause was vasoconstriction, the narrowing of blood vessels to conserve body heat when exposed to cold. Reduced blood flow to the skin increases the amount of blood in the body's core, leading the brain to think that the body has plenty of fluid, even when someone is actually dehydrated. This in turn leads to a decrease in the perception of thirst. Kenefick published the results of these experiments in the journal Medicine & Science in Sports & Exercise.
Kenefick is planning a third study to see if it's possible to stimulate thirst in the cold. The military and other groups who work outside in the cold are interested in his results. "Humans are tropical animals," Kenefick says. "We have all kinds of adaptations to heat—we sweat more, our sodium levels go down, our heart rate goes down. But we don't appear to adapt as well to cold."
When it comes to designing research projects, plant biology professor Subhash Minocha encourages his students to envision a big, meaningful outcome and then set a series of milestones to reach it. Genetic engineering is the means of accomplishing their goals, which can be practical, pollution-preventing, or, in at least one case, just plain fun.
Consider the purple loosestrife project. Instead of looking at ways to eradicate this highly invasive plant as it marches across our wetlands, some of Minocha's students are trying to enlist the species in cleaning up pollution. They hope to engineer a form of purple loosestrife that can remove lead, cadmium and other heavy metals from the soil.
Another group of students is hard at work trying to clone barnacle glue. If you have ever tried to pull a barnacle off a rock or the bottom of a boat, you know how strong its glue is, even underwater. "There is interest in this kind of product from the medical industry because they need a glue that will work on bones after surgery," Minocha explains. "The Navy, too, spends a lot of time cleaning barnacles and mussels off their ships, and they're wondering if there's a way of preventing the attachment. If we know more about how the gene works, there might be a way of dissolving the glue."
Minocha has a larger goal of his own: to bring students into the lab to learn the basic techniques of genetic engineering. "And they have fun doing it," he notes.
Remember the glow-in-the-dark fish that came on the market a few years back? Some of Minocha's students are trying to transfer a fluorescent jellyfish gene into petunias and African violets in hopes of producing glow-in-the-dark flowers. "These plants are curiosities, certainly," says Minocha, "but the ornamental flower industry might be interested in them, and it may be a patentable technology. I read recently that a group of biologists are using similar techniques to try to create Christmas trees that will twinkle in the dark."
Most genetic engineering done on plants, of course, is for a much more practical purpose: to increase crop productivity and help agriculture become more sustainable. In America today, roughly two-thirds of major crops like soybeans, corn, canola and cotton are grown from genetically engineered plants.
Minocha's students may have fun working on their projects, but genetic engineering is serious science, he says. Any project that involves recombinant DNA must be approved by the Institutional Biosafety Committee, on which Minocha sits. "There are strict guidelines that students have to learn and follow," he notes. They also learn to consider and address possible unintended consequences. Take the chemical-collecting purple loosestrife, for example. "Of course, the biggest fear here is that if it works, it could spread all over the place, and then animals would eat it," becoming contaminated, Minocha says. "So a next step would be to create a sterilized plant that wouldn't produce seeds."
Like other scientific endeavors, genetic engineering projects take time. In the glue project, Gwendolyn Bennett '05 cloned the gene from the barnacle. After she graduated, another student, James Rankin '06, took up the project. For his honors thesis, he is figuring out how to transfer the gene to a plant cell. Other students are now trying to find a way to produce these cells in large numbers.
The 33 hoppers who were successfully tracked throughout the project were observed seven days a week from April through August and on weekends through November. The researchers hope to draw some conclusions about where wood frogs spend most of their lives after their first few months.
Ice is an amazing archive. For the past few decades, scientists have been drilling into polar ice sheets and analyzing ice core samples to reveal rather astounding data about climate and environmental changes.
Ice cores not only record the recent history of greenhouse gases, other atmospheric pollutants and global temperatures; as scientists drill deeper, they find information about climate variations, atmospheric chemistry and global changes that took place before humans started messing about.
One of the most important findings in recent years indicates that catastrophic climate change can happen quickly—in a matter of decades rather than over millions of years as previously believed.
As part of the ongoing ice core research, atmospheric chemists are asking some important questions about ice core data. This June, research associate professor Jack Dibb of UNH's Institute for the Study of Earth, Oceans and Space will lead—as he has for the last five Arctic summers —a UNH team to Summit, Greenland.
The team chooses to go in the arctic summer because sunlight plays an important part in their research—studying snow photochemistry to find out how sunlight-initiated reactions in the snow affect its composition and the atmosphere above it.
In 1998, the Summit team found an interesting anomaly. They were measuring levels of nitrogen oxide, and their models indicated that they would find small amounts. Nitrogen oxide has a complicated chemistry, but if there is a lot of it in the atmosphere, you get smog; in the Northern hemisphere, its primary manmade sources are tailpipes and smokestacks.
One would think that Greenland, with a population of about 56,000 and little industry, would not have a smog problem. But readings taken 26 feet above the snow were surprisingly high, and they got higher closer to the surface. "When we measured levels in the snow, the numbers were astronomical. This was extremely puzzling," says Dibb.
Dibb and his team surmised that a complicated process of chemical decomposition and cycling takes place between the air and the snow when sunlight hits the surface. "Prior to our findings in 1998, scientists thought that when it rained or snowed, reactive gases were taken out of the atmosphere and that was the end of the story," he says. "Now we understand that some reactive chemicals are produced in sunlit snow. Some are destroyed, too. And some then circulate in the atmosphere."
Sunlight-initiated reactions also change the makeup of the snow and ice. Better understanding of these reactions will help ice core researchers reconstruct what the atmosphere used to be like.
The team is studying the snow in a number of ways. They measure highly reactive chemicals that clean the atmosphere. They also measure chemicals that form radicals—hydrogen peroxide, formaldehyde, nitrous and nitric acid. Since many of the chemicals are affected by sunlight, they are working to understand the amount and wavelengths of light that get into the snow pack and how this varies as a function of depth. And finally, they are determining the physical structure of the snow pack.
The UNH team's ultimate goal is to create a model of photochemistry in the snow pack that would allow them to predict the impact of snow reactions. "If we're not including, for example, the nitrogen oxide produced by snow in climate models," says Dibb, "then there's a hole in the understanding of how the atmosphere is functioning. We need to understand whether this flux of reactive chemicals out of the snow really matters."
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