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Weighty Research: Mass Spectrometry Gives Students Advanced Lab Experience

Students sharing the MALDI/FTMS in Stemmler's chemistry lab.

Story posted August 24, 2006

At the heart of Chemistry Professor Beth Stemmler's lab is a large, cylindrical instrument reminiscent of a commercial lobster steamer. It has, in fact, been used to trap various lobster peptides, but there the similarities end.

This is the Matrix Assisted Laser Desorption/Ionization Fourier Transform Mass Spectrometer, or MALDI/FTMS, for short (sort of). It is among the most advanced instruments for measuring molecular mass, distinguishing differences down to the mass, or weight, of a single electron. It can be used to trap and break up complex molecules to determine how atoms are connected and to elucidate molecular structure.

Beth Stemmler
Beth Stemmler

It was a true coup for undergraduate research at the College when Stemmler acquired the MALDI in 2001, with a major grant from the National Science Foundation. Bowdoin became the only undergraduate institution in the nation to own one.

Today, the MALDI is at the vortex of a growing body of groundbreaking cross-disciplinary research among Bowdoin scientists - and their students - in fields including chemistry, neuroscience, and environmental science. During the summer months, when Bowdoin faculty members can concentrate more intensively on their research, the traffic pattern in Stemmler's lab gets downright zoo-y.

On this August day, six student researchers crisscross the lab, taking their turn on the MALDI as part of various research projects.

Chris Cashman '07, a biochemistry major, is using mass spectrometry to help identify neuropeptides called orcokinins, which are present in a variety of crustaceans. An earlier research collaboration between Stemmler and Neuroscience Chair Patsy Dickinson turned up entirely new members of the orcokinin peptide family.

Beckman Scholar Chris Cashman '07

Using the mass spectrometer, Cashman is seeking out the newly discovered neuropeptide in a variety of crabs, lobsters and shrimp. "So far," he says, "we have found 12 new peptides within that family.

"We think it's like a big tree," he says, hands gesticulating widely. "Whenever these animals start to diverge you see a difference in the orcokinins. I'm identifying which ones are in different animals and hope to use that info to further our understanding of the evolutionary relationship between the crustaceans. Orcokinins have even been found recently in insects, which is pretty cool."

Summer Student Research

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Lucas Amundson '06, left, and Emily Bruns '06, exchange research data.

"I just graduated as a chemistry major. I stayed because of the ambience of summer research. It's a different type of research than what you do during class, which is very meticulous and systematic. The whole thing about summer research is that it's actual research: You are doing graduate-level work as an undergraduate. So you have a lot of freedom because it's all new ground. You have a goal - sometimes it's a goal for the day, sometimes it's the goal of summer - and you just kind of work your way through it. Sometimes it works, sometimes it doesn't. If it doesn't, you learn more what not to do, and that can be very valuable."
- Lucas Amundson '06

Anna Conterato '07, a biochemistry major, is working with both Stemmler and Dickinson on research that complements Cashman's. Once he identifies the neuropeptides in the MALDI/FTMS, Conterato can analyze DNA from the same animals.

"I want to see if their sequence in DNA matches what we're finding in the mass spectrometer," she says. "I'm also looking for any translational modifications, so you can see evolutionary changes and what mutations look like. It is a way of using mass spectrometry to verify Patsy's work."

Conterato takes a moment to distill her summer research experience, landing, finally, on the richness of her interactions with her faculty mentors. "It's great to work under two women scientists so respected in their fields," she says. "It's just a really casual atmosphere and they're very supportive. It's a wonderful opportunity. Plus, getting trained on the MALDI opens up a lot of doors."

These patterns of collaboration - between professors, among students, across disciplines - are precisely what Bowdoin scientists had in mind in their proposal to fund the instrument. Increasingly, says Stemmler, these collaborations are becoming a part of the global scientific landscape.

"Right now is a time of intense collaboration between biologists and chemists doing mass spectrometry," Stemmler notes. "Analyzing materials at a molecular level is critical for understanding how cells are functioning and how other biological processes are taking place. Mass spectrometry provides details about the structure of biomolecules that are not available using other instruments.

"Working on these biological questions has been a challenge for people doing mass spec and has resulted in the development of so many different ways to analyze and ionize these much more complicated molecules."

Student researchers
Summer student researchers, l. to r., Lucas Amundson, Mathilde Sullivan, Kevin Hoagland-Hanson, and Emily Bruns (seated).

Other student researchers working in Stemmler's lab over the summer include Emily Bruns '06, Mathilde Sullivan '07, Lucas Amundson '06, and Kevin Hoagland-Hanson '09. Their research is supported through grants from the Howard Hughes Medical Institution, National Science Foundation, Beckman Scholars program, the Maine IDeA Network for Biomedical Research Excellence (INBRE), and Merck/AAAS Undergraduate Science Research Program.

Pictured above:
Students sharing the MALDI/FTMS in Stemmler's chemistry lab.

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It's great to work under two women scientists so respected in their fields.
— Anna Conterato '07