Biology

Table of Contents

Personal Misconceptions of Science Perpetuated by a Rabbit, April 5, 1997
Wisp Intern Key Player in Interdisciplinary Effort to Model Mitotic Spindle Formation, April 19, 1997
Sophomore Hanke Assisted in Mountain Gorilla Field Study and Gained Perspective on More Than Primates, May 3, 1997
Biogeo-What? Biogeochemistry! July 13, 1997
Looking at Biology Through a Chemist's Eye, October 29, 2001
Did You Know...? Lights, Camera, Action!, April 1, 2002

Back to 'WISE Stories' Table of Contents

Personal Misconceptions of Science Perpetuated by a Rabbit

By Michelle Nichols '98 April 5, 1997

Michelle Nichols '98 is a BGEN and CHEM double major working in Dr. Joyce DeLeo's lab studying chronic cancer pain. This essay, along with essays written by Christie Jackson '97 and Georgina Garcia '97, were winning entries in a contest sponsored by the American Association for the Advancement of Science (AAAS). Their essays will be featured in the AAAS publication, Collaboration for Equity, Science for Girls.

The Myth

Do you think that "science" is a bald man donning a starched white lab coat and goggles in a lab of gurgling test tubes and spiraling glassware?

Though both of my parents were scientists, this media portrayal of science in the Bugs Bunny cartoons and Disney movies of my youth still affected my perception of the discipline until I came to college. When I found that my college was offering science internships to their freshmen women, I was overcome with excitement. Sadly to say, I was more impressed with the idea of having a lab coat of my very own and entering an atmosphere of mysterious, brilliantly-colored chemicals than capturing the enthusiasm that brought my parents to studying science.

I received an internship position that fall working in the anesthesiology lab of the College's medical center. Two years later, I am still working in the same lab, characterizing the role cytokines play in chronic pain. [Cytokines are growth regulatory proteins of the immune system that have been suggested as possible biochemical factors for pain stimulation after nerve injury.] Fortunately, the mad scientist stereotype has proven short of reality, and I've "contracted" from my professors and colleagues in the lab their contagious excitement about science.

Fortunately, the mad scientist stereotype has proven short of reality, and I've "contracted" from my professors and colleagues in the lab their contagious excitement about science.

The Exciting Reality

First to dispel my naive image of science is that the professor whom I work for is neither bald nor a man, but a vibrant young woman and mother, successful and happy with each facet of her life. As for the physical environment, there are no foul vapors spewing from frothy green mixtures. Lab equipment is practical, and though externally "non-flashy," they aid in revealing extraordinary cellular and molecular landscapes that rival any fantasyland.

With all the abstraction of emotion, my enthusiasm for science is a bit harder to describe. To me, the wonder of science is in its lack of answers. Paradoxical statement perhaps, but the adventure and satisfaction of embarking on a problem to which no one knows the answer is exhilarating. In my work, I picture myself as another Lewis & Clark charting the uncharted. Instead of the topography and cultural geography of an American West, I am mapping the distribution of cytokines in a segment of nervous tissue or the cell types associated with a given hormonal response.

The Motivation

Beyond the intellectual excitement, the medical research I am a part of has a social context, the potential to help millions! Having seen my grandfather suffer through chronic cancer pain, the work I do takes on a personal mission as well. Thus, the people whom I will help with the long-term ramifications of my research are not faceless; I can replace each with the face of my grandfather, and my passion for seeking scientific solutions only intensifies.

A Valuable Lesson

I have realized that real science is not a convoluted maze of glass but that the true wonder of the discipline is revealed in solving its queries. Neither is science a field dominated by eccentric old men. The most amazing women I know are scientists.

Through my research experiences, I have realized that real science is not a convoluted maze of glass but that the true wonder of the discipline is revealed in solving its queries. Neither is science a field dominated by eccentric old men. The most amazing women I know are scientists. Several years ago, the title of a library book caught my eye. It was entitled, Pink is for Girls, Blue is for Scientists. Well, pink is a way cool color for science too.

Wisp Intern Key Player in Interdisciplinary Effort to Model Mitotic Spindle Formation

By Liz Maier '97 April 19, 1997

When Dr. Duane Compton of the Dartmouth Medical School decided to incorporate a computer modeling approach into his laboratory-based research, which investigates the formation of the mitotic spindle during cell division, he turned to the Thayer School of Engineering for assistance. Professor Laura Ray, a mechanical engineer, took up the challenge and presented it as a Women in Science Project internship opportunity for first-year women. The proposal attracted Susan Ashlock, a freshman whose knowledge of computer programming suited the project, and with her addition, the team was complete.

The Science of Microtubule Assembly

The resulting venture into the integrated worlds of biochemistry, mechanical engineering and computer science has produced some promising models of microtubule movement and coordination and has developed into a rewarding research experience for sponsors and intern alike. The success of the internship can be attributed in large part to mutual enthusiasm. "I have had a great time working with Susan," said Compton. "She is really bright and always seems to ask the right questions." Ray agreed. "She did more in the first two weeks than I thought she'd get done all term!"

This is not a surprising comment, considering the complicated nature of the project, which seeks to isolate the mechanisms by which microtubules, or protein filaments, organize into the mitotic spindle during the metaphase stage of cell division. The tubules radiate from two cylindrical centrioles at opposite ends of the cell nucleus, forming two asters, or star-shaped configurations, which comprise the spindle. Near the center of the nucleus, chromosomes attach to the free ends of the microtubules by their centromeres, and the spindle segregates them into two groups of DNA.

The molecules responsible for the organization of microtubules are called "motor proteinsthat is, they can grab onto a microtubule and push it or pull it around," said Compton. These free-floating peptides have a strong affinity for microtubules and will bind to them anywhere. Once attached, a motor protein will "cruise along the length of the microtubule" and right off the edge, unless it bumps into another tubule first. If the second tubule's mass is small, the motor protein may slide it along out in front (like a snowplow), until the tubules are no longer crossed.

"What we found in our biochemical experiments is that there is a complex balance between pushing and pulling forces," Compton explained. This complexity makes it "difficult to figure out how each motor is working in the process." By creating a model of mitotic spindle formation, Susan is helping Compton to define the roles of each type of motor protein and how they coordinate to move microtubules into the aster formation found in his cell extract experiments. "Here we're bringing mechanical modeling aspects into biology," said Ray.

Enter Susan

Susan is used to seeing complexity reduced to its simpler parts. Her father, an electrical engineer, "always had little projects that he was working on," such as building an extension to the garage, or repairing the family vehicles. "I don't think we've ever actually brought anything to a mechanic," Susan mused. "That would be too easy!"

Susan took a formal course in computer programming one summer, and now she is writing her own.

Her family never bought a computer from a store in the traditional sense; instead, her basement is full of keyboards and mother boards. "Computers have always been around...all around our house, in various states of assembly," she said. Encouraged in her youth (and sometimes bribed"I'll pay you a dollar if...") by her father to read books about computers, Susan took a formal course in computer programming one summer, and now she is writing her own.

Susan and Professor Ray meet regularly, and the whole team convenes now and then to share ideas and to choose which direction to move in next. "It works best if we brainstorm on our own and then meet together and discuss the ideas we've had," Susan said.

However, when it comes time to translate ideas into computer code, Susan does the work by herself. From a skeleton Matlab program that generates a random arrangement of tubules, which appear on the screen as a jumble of arrows colored green and yellow to distinguish positive and negative ends, Susan has written several programs calling a multitude of functions that move tubules forward and backward, in the hope of generating that perfect aster shape. In an early program, Susan defined three variables: "the probability of [a tubule] moving forward or backward", how far along the tubule moves when it does move forward, or the "strength of the forward movement," and "the strength of the backward movement." She chose five values for each variable, generating 125 (53) combinations to try. "That was fun," she laughed, rolling her eyes. "Some of them were all over the place, and some of them were a little closer," she said, referring to the final positions of the tubules, but no combination resulted in an aster.

She tried other ideas, other programs, in which she would "plug [conditions] in, run it through a bunch of times, kind of look at it, scratch [her] head and say, 'That doesn't look so great.'" Finally, though, she and her sponsors came up with an idea"kind of a light bulb"suggesting that when a tubule overlapping another tubule moves forward until it is just touching at its end, and the second tubule also moves forward, so that the two meet end to end, the ends stick. Compton's lab calls this sticking phenomenon "end specific activity". Once stuck, the two microtubules move as one, adhering to the ends of other tubules, until an aster forms.

Persistence

Susan put the idea into code, and...It worked! I was ecstatic!" she remembered...

Susan put the idea into code, and..."It worked! I was ecstatic!" she remembered, for it worked consistently, under all sorts of initial conditions. "We're done," she had thought. "We got the answer. But no, it's not that simple.

It turns out that you can't just have one mechanism like that, because that doesn't match what [Compton] observed. It can't be that simple! So that was kind of disappointing." The laboratory experiments had isolated four activities, two forward-moving ones, one for backward movement, and the end specific activity; Susan's model only used two. "Basically...we're accumulating all these different processes that probably work together, and eventually we'll make one big program that incorporates all these ideas," Susan predicted. Despite the frustrations of "sitting there in the computer lab feeling lost," because "things aren't working" or the next step is cloudy, Susan said that she "genuinely looks forward" to her internship, "because it's different from class assignments, where everyone is doing the same thing, and you have to do this, because people tell you to. It's something different and neat. And other people are really excited about it too."

She likes the fact that she is contributing to a larger project, and one with implications for cancer research, as many cancer drugs are able to stop the growth of furiously dividing cells by disrupting the formation of their mitotic spindles. And, of course, when her programs work, she feels especially rewarded. "Sometimes I run [a program] over and over again, not necessarily looking at it really that closely, but just saying, 'Wow! Look at them move! It came out perfectly!'"

"One thing that kind of surprised me was how much I'm doing on my own," Susan said. "It's not like I'm helping anyone with the programs. I started everything from scratch...I don't think too many people get a chance to do that."

Sophomore Hanke Assisted in Mountain Gorilla Field Study and Gained Perspective on More Than Primates

By Liz Maier '97 May 3, 1997

Alexa Hanke was featured in the Thursday, April 24, 1997 edition of the "D." This is a follow-up profile of Alexa that focuses on the scientific aspects of her experience. Alexa's trip is a great example of how one can use an off term to explore scientific interests outside of the Dartmouth classroom.

A Unique Opportunity

Alexa Hanke heard the news that she had been selected to join Anthropology Professor Michele Goldsmith in Uganda last winter, to assist in a pilot study of mountain gorilla ecology, in a round-about way. "It was just kind of interesting," Hanke remembered. Professor Goldsmith simply "told me she'd made a plane reservation in my name," Hanke said. "OK, I guess I'm going!" For a biology major (modified with anthropology) and environmental studies minor, who has "always been interested in working with animals" and has seven years experience doing just that, the decision to take the job was an obvious one.

"I'd never been [to Africa] before," she said, "and because of the field work...something I'd never done before, either, I didn't know what to expect."

A Colorado native who was "surrounded by nature" as a child and for whom "camping is not that big of a deal," Hanke still "had no expectations" when it came to studying mountain gorillas in the wild. "I'd never been [to Africa] before," she said, "and because of the field work . . . something I'd never done before, either, I didn't know what to expect."

What she discovered in Uganda were "random sicknesses where you feel gross, but you don't diagnose it, because you just don't want to know what it is," but also "the thrilling part of being in the rain forest and being woken up by the call of the chimpanzees in the morning, or black and white colobus monkeys, and seeing amazing birds flying everywhere, and being surrounded by parrots . . . it was so incredible," she said slowly, as if searching for the right words. "Being charged by an African forest elephant-definitely a frightening experience, but very cool at the same time, too!"

There were "little things, like walking home by the light of a full moon, where it was like daylight outside," she said, gazing off into a scene no one else in the busy dining hall could see, or likely would see, but which came vividly to her, still. "Or walking down a trail and seeing all these monkeys zoom about, or the experience of being in a foreign country-something so different-where the people are so friendly, and they love it when you try to speak their local language. Honestly, I couldn't pick a best part!"

The Research

The Dartmouth '99 assisted Goldsmith with a two and a half month study of the comparative ecology of mountain gorillas and chimpanzees in Bwindi Impenetrable National Park, a collaborative project with chimpanzee expert Professor Craig Stanford of the University of Southern California. Goldsmith and Hanke focused on mountain gorillas rather than chimpanzees, examining their feeding and nesting habits by indirect methods such as collecting dung samples, which provide insight into what the gorillas were eating (primarily herbaceous vegetation like leaves and bark, they found), and observing their behavior for several hours each day. Hanke also directed her own research project on the nesting behavior of the gorillas.

"The basic data we were collecting was dietary information and path length-how far they travel each day from nest site to nest site," Hanke said. "And then I was doing my main work on the actual nest site and nest site behavior. Each night, all weaned gorillas will build a new nest for sleeping, and what I'm basically looking at is if there is any kind of relationship between the position of lactating females with regard to the silverback, who is the male."

Goldsmith and Hanke tracked harems of gorillas at two sites, one at low elevation, a tourist camp called Buhoma, and the other at high elevation near Rhuija, where the Institute for Tropical Forest Conservation (ITFC) is based.

Mountain gorilla social groups known as harems consist of the silverback and adult females with their infants, Hanke explained. Male gorillas may travel alone or in all-male bands and look for opportunities to oust silverbacks, taking charge of the now leaderless harem. Goldsmith and Hanke tracked harems of gorillas at two sites, one at low elevation, a tourist camp called Buhoma, and the other at high elevation near Rhuija, where the Institute for Tropical Forest Conservation (ITFC) is based.

The actual high altitude base camp was a two hour hike from Rhuija and was located in a swamp. "We were boiling swamp water in the mornings," Hanke recalled. "You'd pour the water into your water bottle, and there would be a layer of dirt this thick," she laughed, spreading her thumb and forefinger several inches apart.

Because few previous studies have been done on the Bwindi population of mountain gorillas, the objective of the Dartmouth study was to gather basic information about the population that could be compared to Stanford's chimpanzee data to determine whether the relationship between the species was competitive or peaceful. Do they nest in the same area and travel the same routes, or do they avoid each other? Do they eat the same foods? "If it is the fruiting season and all of a sudden all of these chimpanzees start screaming," proposed Hanke, "would the reaction of the gorillas be, 'OK, let's go there, because there's probably fruiting trees over there?'" No one had looked at the interaction between these two species before Goldsmith's research, she said.

Studying animal behavior and ecology was nothing new to Hanke, however. "My high school-Millbrook School in Millbrook, New York-had its own fully accredited zoo," she said. "I worked with animals there for four years, and I still work there when I go home." During her senior year in high school, she undertook a year-long honors project studying Japanese macaques, short-tailed monkeys native to Japan, Southeast Asia, and North Africa. She did a literature review of their "basic natural ecology in the wild" in the fall, spent the winter looking at "competition of the group of Japanese macaques" at the zoo and "drawing the layout of the enclosure," and then in the spring did an "environmental enrichment, behavioral project," she said. She observed macaque behavior before and after adding bamboo to the cage and other stimulation.

Her familiarity with primate habitats was helpful to her in Uganda, where she characterized nest sites where gorillas had slept the night before; the sites were always unoccupied by the time she arrived. By measuring dung size, she could infer which gorillas (silverback, females or juveniles) had slept in each nest, which she recorded in her book of nest sites, along with a number representing the quality of each nest, or how well it was constructed, and a description of the nesting material used. She mapped the nest site by standing at one nest, taking compass readings of the surrounding nests, and pacing out the distances to them from the central nest.

Hanke hopes to publish her results in the American Journal of Primatology, and she will be presenting her work a year from now at a Physical Anthropology meeting in Salt Lake City, Utah.

Now she is transferring the data from her maps to Microsoft Excel spreadsheets, and once she finishes the data entry, she will perform a statistical analysis to see if there is a significant relationship between the distance of a given nest from the nest of the silverback, and who slept in that nest. Hanke hopes to publish her results in the American Journal of Primatology, and she will be presenting her work a year from now at a Physical Anthropology meeting in Salt Lake City, Utah.

Opportunities For Others

"If anybody is interested in this kind of [work] . . . help volunteer at a zoo," she advised. "I feel that a zoo is the easiest place where you can get the one on one interaction with an animal. It also gives you a new aspect, kind of a behind-the-scenes look at zoos and what they mean to you."

Hanke thought that Professor Goldsmith may return to Uganda next winter to continue her mountain gorilla research and would be looking for another student to take with her. "It's definitely an amazing opportunity [for] any student who is interested in pursuing a career in wildlife biology . . . and can really take camping for two and a half months, and boiling the water, and getting sick with giardia and worms and all random kind of illnesses. If you can deal with that, and if you want to be in another country, then I'd say definitely take advantage of the opportunity and go talk to Michele."

Overcoming Obstacles

While the discomforts of camping may make some think twice about doing field research, what Hanke "was really scared about was being in a situation where you're living with a person for twenty-four hours, for two and a half months straight, and you barely know this person at all. Sure you get along after class and when you talk to them and things like that, but you never know what it's going to be like, especially under field conditions."

"I can honestly say that Michele and I got along so well, and it was such a blessing, because it could have been an absolute disaster, even if I was doing the thing that I loved," she said.

"Everything just seemed to work out perfectly on that trip," Hanke added. "So much could have gone wrong, yet nothing really did . . . maybe luck was just on my side or something!"

"So much could have gone wrong, yet nothing really did...maybe luck was just on my side or something!"

She felt the toughest part of being in Uganda was when she spent a week alone in the forest, with no pots and pans or silverware, and no cooked food. "Michele and I got into Bwindi on the first of January, and on the second of January we had our first day of work, where she taught me how to deal with the nest site, how to collect data, how to do a path length. On the third of January, she left to go to a chimpanzee conference," Hanke said. "I would do my work, but there would be some times during the afternoons where I would just all of a sudden think of my parents, and I'd really miss them, and I'd feel very, very far away."

She recounted one lonely episode in particular, when she borrowed a pot to cook some rice in instead of spending money on food at the tourist canteen, and it took forty minutes for the water to boil and even longer for the rice to cook. "It cooked for an hour and a half, until all the water got absorbed," she said. "I tried tasting it, and it was the most disgusting rice I've ever had! And all the while I'm writing in my journal . . . 'twenty minutes later, checking the rice . . . I really miss my mom right now. I really miss home-cooked food!' And then I just tried this rice, and it was the most disgusting thing, so I went to bed and said, 'Forget it!'"

Plans for the Future

As the trip wore on, the bouts of homesickness came less frequently, and now Hanke may return to Africa next winter as part of the Environmental Studies Foreign Study Program (FSP) in Kenya. "I've definitely been bitten by the Africa bug," Hanke said. She would like to work with national parks in the future. She imagines herself doing field work to determine where land should be set aside for wildlife and then working with local communities to set up multiple-use parks, where villagers can collect medicinal plants, for instance, rather than paying for treatment they cannot afford.

"After going to Uganda, I see that there's . . . a poor relationship between the local communities and the parks people or the actual national park itself," Hanke said. "Local communities will see so much money going into these parks every day and yet get either nothing or a very small percentage out of it. I think that's a relationship . . . that has to be strengthened. I think eventually what I'd like to do is work on strengthening those relationships."

She sees not only the value of these parks to human beings, but also the critical role they play in providing refuge for endangered species like the mountain gorilla. "They are our link to our biological evolution," she said of gorillas. "I think all species . . . should be protected, [because] they know how to interact with their environment; they are in balance with that, and we are a species that definitely isn't. I think that we should really look at the world around us and see how all elements are interacting, and the knowledge we gain from that . . . we should use . . . to figure out how we should interact with our own environment."

The Personal Impact

"I mean, I've always loved my life and been very grateful for everything, but I never had the feeling of waking up every single morning and being grateful for every single thing that is around me."

From her off-term experience studying primates in Uganda, Hanke has gained a new appreciation not only for her life at Dartmouth, but for life in general, she said. "I had some realizations while I was out in the field . . . I couldn't really pinpoint when they happened, and I don't really know exactly what the realizations are, but it's one of those things where I've come back now, and I feel so much more happy than I did. I mean, I've always loved my life and been very grateful for everything, but I never had the feeling of waking up every single morning and being grateful for every single thing that is around me."

"It hasn't worn off yet, and I hope it never does," Hanke said, smiling. "I have been so happy, the happiest I've ever been in my life."

Biogeo-What? Biogeochemistry!

By Liz Maier '97 July 13, 1997

Biogeochemist Andy Friedland describes his field, how he got there, and where it might lead you!

I had a chance to ask Professor Friedland a few questions about what it means to study biogeochemistry, an interdisciplinary field that draws upon almost every basic science out there. Have you ever studied the nitrogen cycle? The increase in global atmospheric CO2? Acid rain? Then you have been exposed to biogeochemistry! Professor Friedland teaches a number of Environmental Studies classes, including: ENVS 1, Humans and Nature in America; ENVS 2, Earth as an Ecosystem; ENVS 79, Soil Science; and ENVS 89, Forest Biogeochemistry. If this interview piques your interest, be sure to investigate the new biogeochemistry web site at: http://www.dartmouth.edu/artsci/envs/courses/envs89.html, for more information about red spruce decline and other biogeochemical issues.

Q: How did you get interested in science?

A: I don't know exactly, but I know I became interested in the environment in fifth grade, and I know that it was environmental science that I became most interested in. And that's because my fifth grade class, as part of the first Earth Day in 1970, went to what was then called a swamp -- Red Maple Swamp, near my elementary school. We cleaned up the litter and trash, and made some trails.,..and learned some of the species and things like that. So when people say, " Oh, I'm going to be an elementary school teacher," and some people treat that with disrespect, I think you have a great opportunity to influence a lot of people that way, and I think that's what got me interested in science.
So when people say, "Oh, I'm going to be an elementary school teacher," and some people treat that with disrespect, I think you have a great opportunity to influence a lot of people that way, and I think that's what got me interested in science.

Q: What did you study in college?
A: I did a double major in ecology and environmental studies. I was pretty sure by the time I was in college that I wanted to focus on environment, but since my most exciting teacher in high school had been a history and constitutional law teacher, I came in thinking I wanted to do political science and international relations. And then I envisioned that I would use that to become some sort of environmental lawyer or environmental governmental official. But -- this was at the University of Pennsylvania -- in this course in international relations my freshman year, you'd have to wait in line for an hour to see the T.A....not the professor, the T.A.! And I very quickly moved away from international relations and found the environmental studies department, which was really the same thing as the geology department, which was my undergraduate home. And then I ended up staying at Penn and doing a Ph.D. in geology.

Q: What convinced you to go to graduate school?
A: It's not something that I planned. Lots of times I talk to undergraduates who want to lay out their whole [career], and I always refer to that as trying to line your ducks up in a row. Sometimes that's doable, and I try to do that, but other times you just sort of see what

In no way was there a master plan. I just took good opportunities.
opportunities there are. I got the opportunity to work with a professor of geology and environmental studies, and we did some field work, and that just rolled into some other

work, and they said, "Why don't you consider doing a Ph.D. here?" In no way was there a master plan. I just took good opportunities.

>Q: When did you decide to become a professor?
A: The thought was to get a Ph.D., but I thought I might do environmental consulting or work for the government, work for the EPA....I guess by the time I was at the end of my Ph.D., I thought that it would be a great opportunity to be able to do research and teach.

Q: What did you do your graduate work in?
A: My graduate work was in trace metal biogeochemistry in forested ecosystems.

Q:What is biogeochemistry?
A: Biogeochemistry is the study of interactions between the atmosphere, the terrestrial biosphere, and the underlying soil and bedrock.

Q: What projects did you work on when you first came to Dartmouth?
A: I came to Dartmouth and had been involved with looking at red spruce decline, which we eventually showed was connected to air pollution, although not exclusively air pollution. I came in the fall of '87, and by the summer of '88 I had a couple of Dartmouth undergraduates and a bachelors student from the University of Pennsylvania (who couldn't get an advisor at Penn, so called me up and asked if I'd be his advisor for his bachelors thesis at Penn), and a couple other people, and we went running around the mountains of New England and New York making measurements relating to red spruce decline. And in that study, which was the only one that really looked at a west-east gradient, meaning that air pollution decreases as you go from west to east, we looked to see whether red spruce decline decreased as you go west to east, and in fact it did. It did not prove that air pollution caused the decline, or the lack of decline to the east, but nevertheless it was an interesting correlation. That was pretty prominently cited in a few locations in the National Atmospheric Precipitation Assessment Program reports about acid rain. So that was something I did just very quickly on coming.

Another thing I got started on [I] worked on very closely with an undergraduate...named Graham Herrick, who ended up doing a lot of good work with me. I was here now all of a

sudden really close to mountains, and working in the winter was an option, whereas when I was in Philadelphia, it was kind of a hassle. I would often try trips in the winter, but storms would either prevent me from getting up to Camel's Hump or from getting back after a trip.
I was here now all of a sudden really close to mountains, and working in the winter was an option...

Whereas here, I could, depending on the day, go or not go, depending on the weather. It was much easier, because it was all within an hour's drive. So Graham and I designed a couple of projects, one of which he did most of while I was in Kenya, where we looked at water relations in needles on Mount Moosilauke. So that was perhaps the second project I started after coming to Dartmouth.

And for Graham and eventually for me, too, and others who worked with us, one of the most exciting things was that we'd pack these red, plastic sleds that kids use on the golf course. We'd strap them to the pack -- they'd weigh almost nothing -- on the way up, and on the way down, you'd have this thirty minute bobsled run! Of course, we were doing it for the science, right? But it sure was fun. And that helped us get volunteers to come and help us with our work.

Q: What projects are you working on now?
A: One of the major projects I have going on right now is a long-term study of the biogeochemistry of major elements at Whiteface Mountain. This is a collaboration with Eric Miller, who is a research assistant professor in environmental studies. It's a study of the deposition of a variety of elements, particularly nitrogen, calcium, magnesium, and potassium.

If you had to describe my work, I am interested in how human beings have altered or perturbed elemental cycling patterns and rates, and elemental distribution in temperate forests. And I have two focuses: one is a particular system, a spruce-fir-birch system of high elevation mountains in New England and the high Adirondacks in New York; and with respect to elements that I study, there's a group of major elements -- calcium, magnesium, potassium, nitrogen, sulfur -- and trace metals -- lead, copper, zinc, nickel, and cadmium -- with probably the greatest focus on lead.

Nitrogen is presumably an element that did not cycle as much -- there wasn't as much deposited, there wasn't as much cycling -- prior to human activity. Lead was another element, and so for a long time my two contrasting elements were nitrogen and lead. Nitrogen was something plants need in large amounts and we are supplying in large amounts by the combustion of fossil fuels. On the other hand, lead is something we've provided lots of through the use of leaded gasoline, but it's something plants and ecosystems need none of. So that's an interesting comparison to make.

Q: What is the best preparation for students who are excited by your field?
A: I think biogeochemistry has a foundation in ecosystem studies, which is a part of ecology. So I'd say if someone thinks that biogeochemistry is interesting, it's important to know your chemistry and your geochemistry, but the intellectual foundation is in ecology. So

So I'd say if someone thinks that biogeochemistry is interesting, it's important to know your chemistry and your geochemistry, but the intellectual foundation is in ecology.
I'd encourage people to consider taking ecology courses. And another thing would be to consider some of the courses that are available in Earth Sciences. There's Geochemistry and Environmental Geology -- those are two courses that are relevant. And within Environmental Studies, ENVS 30, Global Environmental Science, and then there's Forest Biogeochemistry, of course. So for example, taking a course in oceanography and marine ecology might be relevant, because in some ways the oceans are the

ultimate repository for most of terrestrial biogeochemical cycling. It's really a broad field, and depending on where you get interested, you could find something of interest in almost all of the science departments on campus.

Q: What are the job options for biogeochemists?
A: Among undergraduates who have had a focus on biogeochemistry -- I'm thinking of people who have taken, say, both Soil Science and Forest Biogeochemistry, and other courses in earth sciences and ecology -- I've observed people go on and work in consulting firms in Washington D.C. and Boston and elsewhere, where they are doing various aspects of scientific consulting, whether it's some aspect of the Superfund legislation, or other toxic or hazardous waste-related enforcement or analyses. I've seen people go and do things in the solid waste and recycling fields; I've seen people go and get jobs from other faculty members as technicians -- field technicians, laboratory technicians. People have worked in various environmental institutes of one sort or another, or have gone to work for the EPA or a state environmental protection organization.

Q: So there are plenty of opportunities available in this field without a higher degree?
A: It appears that there are opportunities, although my impression is, speaking to...some people I got to know best, like my Kenya students, people who have been out five and seven years, in the last year or two a great number of them have been going back to graduate school. So it seems like you can go out [into the job market], but that within five years or so, people seem to want to do something more. So they are applying and going to places like Yale School of Forestry and Environmental Studies, Duke School of the Environment, law school, and business school.

Looking at Biology Through a Chemist's Eye

By Chris Wilson October 29, 2001

What does a molecule look like? Why do we need to know? How do computers factor in?

Dr. Amy Anderson in the Chemistry Department in Burke is answering those questions and more (http://www.csbcc.dartmouth.edu/acalab.html). I met with one of her graduate students, Brian Stevens, in the lab one sunny morning. The lab is new, the equipment is new, and some of it is still being unpacked and assembled. Dr. Anderson has only been at Dartmouth for two years, but she already has four graduate students and three undergraduates working for her. Brian showed me around and helped decipher some of what's going on in the lab.

"The structure of a molecule can tell you many things," Brian said. By studying the structure of an enzyme that is essential to the life of a pathogen, antibiotics can be designed to inhibit that enzyme, thereby killing the pathogen. By studying the structure of a molecule of an organism that has become drug resistant, it is possible to visualize how it became resistant, and redesign antibiotics accordingly.

Dr. Anderson has only been at Dartmouth for two years, but she already has four graduate students and three undergraduates working for her.

The Steps Involved

The first step is to extract the enzyme. An enzyme is a protein inside living cells that has a particular function, like enabling DNA replication to occur. To get to the enzyme, grow bacteria that contains the enzyme, place the bacteria in a centrifuge to break the cells apart

Image Credit: Cody, V., Galitsky, N., Rak, D., Luft, J. R., Pangborn, W., Queener, S. F.: Ligand-Induced Conformational Changes in the Crystal Structures of Pneumocystis Carinii Dihydrofolate Reductase Complexes with Folate and Nadp+ Biochemistry 38 pp. 4303 (1999)
to free up the intracellular material, and freeze the samples immediately. The samples must be kept frozen to keep proteins from 'unfolding'. The frozen samples are brought into the cold room, which is kept at 4 degrees C, where the specific proteins are collected using column chromatography techniques. This process takes a few days.

Then the sample is crystallized. This is the step Brian is currently struggling with. Proteins do not form crystals easily, unlike salts and sugars. Brian explained the crystallization process as similar to placing a drop of salt water on a bench and waiting for the water to evaporate, leaving just the salt crystals. Depending on the protein involved, this process can take many trials, and perhaps even months to complete.

Once the protein is crystallized, the sample is placed in a machine that bombards it with an X-ray beam and collects the 'diffraction data', meaning the ways in which the beam reflects off the sample. The diffraction data looks like a bunch of dots.

"Think of diffraction data as an unfocused image in a microscope," said Brian. Using high-powered mathematics and high-powered computers, scientists are able to "focus the picture", adding color to create a visual work of art.

Scientists worldwide are solving molecular structures and making their discoveries available to each other via the web. The structure pictured is from the protein database webpage (www.rcsb.org) where all solved structures eventually get posted and made accessible to the scientific community. The structure is DHFR (an enzyme involved with DNA replication) from the organism Pneumocystis carinii, with two molecules attached, folate and NADP+ (shown in ball and stick).

Scientific Worlds Collide--With Amazing Results

One of the most fascinating things about this research is how interdisciplinary it is, presumably out of necessity. The techniques come from chemistry, biochemistry, molecular biology, structural biology, and biophysics. Intense computing is used to collect data, analyze data, and derive three-dimensional structures. A working knowledge of

One of the most fascinating things about this research is how interdisciplinary it is, presumably out of necessity.

math and physics is necessary to understand and use the x-ray techniques. These scientists are operating in that realm just on the edge of chemistry and biology, where computers meet to give them a bird's eye view into the smallest of worlds. Brian, as an undergraduate, was a double major in biology and chemistry, and he feels like he constantly draws on his core knowledge from both of those sources. And now, as a graduate student, he is "looking at biological molecules as a chemist." With a little bit of computers thrown in.

Did You Know...? Lights, Camera, Action!

By Chris Wilson April 1, 2002

The following is another installment of "Did You Know...?" by WISP's Chris Wilson. Below, Chris discusses the amazing advances in cancer diagnosis being made in Professor Mary-Ann Mycek's physics lab. Chris notes the cooperation that has gone into this interdisciplinary project. Read on to find out more about this fascinating field.

What if a physician could scan the human body with a light wand similar to a laser pointer and the computer it was connected to could distinguish a healthy cell from a cancerous cell? Or maybe it could determine that the cell is exhibiting characteristics that suggest that it will turn cancerous, and therefore should receive a different treatment. Imagine a diagnostic tool that would be safer than x-rays; patients would be able to sit comfortably in their doctor's office during this procedure, and not be subject to long delays, trapped inside the small confined space of the magnetic resonance imaging (MRI) machine. There would be no invasive tissue removal for biopsy. The results would be almost instantaneous.
Dr. Mary-Ann Mycek has been envisioning just such an instrument in her Physics Department laboratory in Wilder, and is well on her way to bringing her vision into reality. Fluorescence spectroscopy is the technique involved. The
Fluorescence spectroscopy is the technique involved. The general premise is that when ultraviolet (UV) light is shone onto tissue, the tissue will "fluoresce" or basically glow (think Halloween light stick). The color, intensity and duration of the glow are signatures of different cells and their metabolisms. Normal cells reflect UV light in very different ways than cancerous cells.

general premise is that when ultraviolet (UV) light is shone onto tissue, the tissue will "fluoresce" or basically glow (think Halloween light stick). The color, intensity and duration of the glow are signatures of different cells and their metabolisms. Normal cells reflect UV light in very different ways than cancerous cells.

The UV light is directed at the patient from a laser source through fiber optic cables. LASER is really an acronym for Light Amplification by Stimulated Emission of Radiation.

This cutting-edge biomedical instrument is the epitome of collaborative effort, from the physics of laser beams and fluorescence, to the biology and chemistry of cells and their metabolisms, to the engineering of the hardware, and the computer programming that links all the pieces together. A laser beam is an extremely narrow beam of intense light of the same wavelength and phase, and therefore very uniform, controllable and predictable. Ordinary light is a mixture of different frequencies of light moving in various directions; it is therefore not uniform. A prototype of the clinical biomedical diagnostic tool is currently up and running in Dr. Mycek's lab. A laptop computer sits on the top of a rack on wheels, with lasers, lenses and fiber optic cables on the shelf below. The fiber optic cable carries the UV laser beam out to the patient and retrieves the incoming light fluoresced from the tissue, as the fluorescence happens very quickly. The lenses diffract or split the fluoresced light into its various parts, or wavelengths. By looking at the quantities of the different

parts of the fluoresced light, a spectrum (or graph of the amounts of each of the various wavelengths) can be created that can be analyzed to determine things like how much of a particular chemical is in the sample.

The data and subsequent spectrum is analyzed using computer programs written by Dr. Mycek and her staff. The spectrum and its implications are then displayed on the screen of the laptop for the physician to analyze. The computer program that acts as the interface between the physician and the hardware was written by people in the Computer Science department to make the equipment more "user-friendly" for physicians in the field. This cutting-edge biomedical instrument is the epitome of collaborative effort, from the physics of laser beams and fluorescence, to the biology and chemistry of cells and their metabolisms, to the engineering of the hardware, and the computer programming that links all the pieces together. Together, it seems all things truly are possible.

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