The Art of Bench Science

Microscope Slides Are Like an Artist’s Canvas for Tim Marquis ’15


The sea lamprey, along with hagfish, is the most ancient living vertebrate species (animal with a backbone). Their ancestors go back 500 million years. By studying the sea lamprey, researchers in Professor Stacia Sower’s lab, including Tim Marquis, seek to understand how its sexual reproduction system evolved and how it compares to what higher vertebrates have now.

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Tim Marquis snags a sea lamprey with a dip net at the Cocheco fish ladder in Dover, N.H. Students in Professor Stacia Sower’s lab help with specimen collection. In late spring, sea lampreys, like salmon, migrate up coastal rivers to spawn in freshwater. A female lamprey will release 500,000 to 700,000 eggs. After spawning, the lampreys die.

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Marquis makes cryosections of the sea lamprey’s pituitary gland. There are several sections per slide. To make the sections, the sea lamprey’s pituitary gland is frozen in an aqueous compound and preserved at -80 ⁰C. The pituitary is removed from storage to be sliced into sections for slides, using a cryostat machine. The cryostat has a small compartment kept at -18 ⁰C and slices sections to 20 millionths of a meter.

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Faculty mentor Stacia Sower, director of the Center for Molecular and Comparative Endocrinology, looks on as Marquis works at the cryostat. Making the sections takes finesse, such as carefully placing the delicate tissue sections on to the slide and warming the back of the slide with a fingertip to relax tissues so they’ll adhere to the glass. With the aid of Professor Sower, Marquis has dissected more than 150 brains and pituitaries of larval, parasitic, and adult sea lampreys.

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After the slides are prepped—all carefully labeled with odd and even slides marked for adjacent tissues—they proceed through several immersions in various chemicals. Marquis calls this process, in-situ hybridization, the “assay” or the actual experiment, which takes three full days to perform.

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Each immersion has a different time requirement ranging from one minute to two hours. These immersions fix the cryosections to protect the integrity of the tissues and signal of interest.

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Marquis uses several timers to keep track of each process. After the immersions, a probe is applied during an overnight incubation at 55 ⁰C, which binds to the signal of interest. Through a series of chemical reactions, the cells expressing the signal are stained, which becomes clearly visible.

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When the slides are fully prepped, digital photographs are captured. Using a confocal microscope, Marquis can clearly see the distribution of hormones in different parts of the pituitary gland. A detailed assessment is made of each slide.

A Researcher’s Path

Scientific Knowledge Is About Opportunities, Collaborations, and Contributions

Tim Marquis ’15 chose UNH because he felt certain that he would have great research opportunities.

Now a senior, Marquis has made significant contributions to sea lamprey research. His critical contributions on the expression of a pituitary hormone subunit, “beta 5,” helped Professor Stacia Sower’s team at the Center for Molecular and Comparative Endocrinology to proceed with a cutting-edge manuscript.

At the 2014 Undergraduate Research Conference, Marquis will present a part of his honors thesis, Distribution and Expression of Glycoprotein Hormone Subunits, GpA2, GTHβ, and GpB5, in the Sea Lamprey, Petromyzon marinus.

This spring, Marquis was one of three UNH student researchers honored to receive a Goldwater Scholarship.

“It was a real honor for me to write the scholarship recommendation for Tim,” writes Sower. “Tim is a gifted, talented student in his academic accomplishments, his intellectual ability, communication skills, and volunteer service. He is a wonderful, contributing member of our laboratory.”

Marquis, from Nashua, N.H., notes that “from a young age I’ve always had always had a strong interest in mathematics and science.” However, it wasn’t until he became a certified Outdoor Emergency Care Technician with the National Ski Patrol that he realized he “wanted to go to medical school.”

When his high school guidance counselor suggested that he look into UNH, Marquis, followed up. He attended a College of Life Sciences and Agriculture Open House where he met the director of the Hamel Center for Undergraduate Research.

“Professor Tsang told me that I could begin researching as a freshman,” recalls Marquis. “That same day I met Professor Sower and she said to come see her in the fall.”

At UNH as a first-year student, Marquis declared a major in biomedical science with the medical/veterinary option because it fit his interest in research and met the requirements for admission into medical school. And he entered the Honors Program.

He also looked up Professor Sower, who directs the Center for Molecular and Comparative Endocrinology. Sower has researched the sea lamprey for three decades and has mentored countless undergraduate and graduate students. Her network of colleagues spans the globe with those renowned in the field. Sower’s laboratory has identified structures in the lamprey brain and pituitary gland, cloned hormones, and sequenced the fish’s genome as well as discovered the gonadotropin-releasing hormone. Some of these discoveries, the results of many contributions and collaborations, have taken 20 years.

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Tim Marquis does find time to relax. He is the principal bassoonist in the UNH Symphony Orchestra. “Music is a wonderful release and it’s a great way to relieve stress,” says Marquis. Their spring concert is Thursday, May 1, at Johnson Theatre. It’s free and open to the public.

At Sower’s lab as a first-year student, Marquis learned biochemical and molecular research techniques for the study of the sea lamprey. His training continued through the summer, thanks to a Research Experience and Apprenticeship Award (REAP).

The following year, as a sophomore, thanks to another Undergraduate Research Award, Marquis continued his work on the sea lamprey. By the fall of 2013, he was coauthor on two scientific papers.

In May 2013, Sower’s esteemed Japanese colleague, the comparative neuroendocrinologist, Masumi Nozaki visited UNH. Marquis was able to spend time with Nozaki, learning his elegant and beautiful slide preparation techniques that clearly delineate different hormones within the same cell.

“Last year I was encouraged to apply for the Goldwater Scholarship and so began my work with Jeanne Sokolowski in UNH Fellowships Office,” says Marquis, the day after receiving the news. “She reviewed my application every step of the way and I got a lot out of the process. Getting this award has been a real honor. And the monetary reward will reduce some of my financial burden.”

Marquis also notes that of the four Goldwater Scholarships awarded to the state, three went to UNH. Says Marquis, “I think that’s a real testament to the culture of research and the quality of education here.”

With medical school ahead of him, Marquis’s expenses will be considerable. His ambition is to become an oncologist with the dual aim of conducting research through applied clinical studies at a cancer institution. Additionally, he would like to teach medical interns.

Written by Carrie Sherman, photography by Lisa Nugent.