On the RISE: Joshua and Caleb Marceau Use NIGMS Grant to Jump-Start Their Research Careers

A college degree was far from the minds of Joshua and Caleb Marceau growing up on a small farm on the Flathead Indian Reservation in rural northwestern Montana. Their world centered on powwows, tending cattle and chicken, fishing in streams, and working the 20-acre ranch their parents own. Despite their innate love of learning and science, the idea of applying to and paying for college seemed out of reach. Then, opportunities provided through NIGMS, mentors, and scholarships led them from a local tribal college to advanced degrees in biomedical science. Today, both Joshua and Caleb are Ph.D.-level scientists working to improve public health through the study of viruses.

Joshua Discovers Unexpected Opportunities

Joshua Marceau examining a specimen in front of a large centrifuge.Joshua Marceau at Salish Kootenai College, where he gained research experience as an undergraduate. Credit: Joshua Marceau.

As the oldest of four brothers, Joshua was the trailblazer in the family. But like most trailblazers, his path to a scientific career wasn’t always smooth. He attended a reservation school until sixth grade, then was homeschooled. He earned his GED through the local tribal community college, Salish Kootenai College (SKC) in Pablo, so he could begin to take college-level chemistry.

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A Scientist’s Exploration of Regeneration

Viravuth (“Voot”) Yin, standing with arms crossed and smiling in front of a shelves holding tanks of zebrafish in his lab. Viravuth (“Voot”) Yin, associate professor of regenerative biology and medicine at MDI Biological Laboratory and chief scientific officer at Novo Biosciences, Inc., in Bar Harbor, Maine. Credit: MDI Biological Laboratory.

In 1980, a week after his 6th birthday, Viravuth (“Voot”) Yin immigrated with his mother, grandfather, and three siblings from Cambodia to the United States. Everything they owned fit into a single, 18-inch carry-on bag. They had to build new lives from almost nothing. So, it’s perhaps fitting that Yin studies regeneration, the fascinating ability of some animals, such as salamanders, sea stars, and zebrafish, to regrow damaged body parts, essentially from scratch.

Yin’s path wasn’t always smooth. His family settled in Hartford, Connecticut, near an uncle who had been granted asylum during the Vietnam War. Yin got into a lot of trouble in school, trying to learn a new culture and fit in. Things improved when his mother moved him and his siblings to West Hartford, well known for its strong schools.

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Surgeon Chris McCulloh Stands Up to Disability

Profile picture of Chris McCulloh with short, light brown hair and wearing a suit, smiling.
Credit: Chris McCulloh.
Chris McCulloh

Job: 4th-year general surgical resident, Morristown Medical Center in New Jersey
Grew up in: Manhattan
When not at work, he’s: Programming, coding, thinking about artificial intelligence, and machine learning
Hobbies: Writing/producing electronic music, weightlifting

Ten years ago, Chris McCulloh planned to enter medical school and fulfill his dream of becoming a surgeon. Instead, just months before he was to start med school, he ended up a patient. A freak accident—slipping on a hardwood floor, flying backwards, and landing neck-first on the edge of a glass coffee table—left him with both legs paralyzed at age 28. Undaunted, he deferred entering medical school for a year, undergoing surgery and spending months in rehab.

Chris McCulloh on a specialized wheelchair that holds him upright, wearing surgical scrubs and cap, in a hospital hallway alongside Elizabeth Vargas, also in scrubs and cap..
McCulloh prepares for surgery while “20/20” host Elizabeth Vargas stands alongside him as part of a 2017 interview.
Credit: Morristown Medical Center.

McCulloh has since finished medical school and recently completed a 2-year pediatric surgery research fellowship at Nationwide Children’s Hospital in Columbus, Ohio. He is now two-thirds of the way through his surgical residency at the Morristown (New Jersey) Medical Center, thanks to the assistance of a specialized wheelchair that allows him to stand nearly to his 6-foot-3 height and helps him perform five to six surgeries a day.

He’s received plenty of attention for being a surgeon with a disability. Along with several print media stories, he was interviewed in 2013 for CBS’ “The Doctors,” and in 2017, ABC’s “20/20” included McCulloh in an episode on physicians with disabilities. But it’s not the wheelchair that distinguishes McCulloh, says Gail Besner, a pediatric surgeon and researcher who hired McCulloh as a postdoctoral fellow. Rather, it’s his enthusiasm, natural research skills, and exceptional surgical prowess that make him special. Besner sees no reason why he won’t reach his goal of landing a highly competitive pediatric surgical residency. “I think he’s capable of doing anything he puts his mind to,” she says.

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Zebrafish Scrapbook

Name: Danio rerio Hometown: Freshwater ponds and rivers of India, Nepal, and neighboring countries Occupation: Research Long-term goal: Solving the basic mysteries of life Work site: More than 600 science labs worldwide
Danio rerio That’s me and some other zebrafish, swimming in a tank in one of the more than 600 labs around the world that use us to study embryo development, genetics, and all kinds of human diseases. Credit: Wikimedia Commons, Azul.

Apart from the tell-tale stripes that give me my nickname, zebrafish, I look a lot like your standard minnow swimming in the shallows of any pond, lake, or river. But I like to think I’m more important than that. In fact, researchers around the world have turned to me and my extended family to understand some of the most basic mysteries of life. From studying us, they’re learning about how embryos develop, how cancer works, and whether someday humans might be able to rebuild a heart, repair a spinal cord injury, or regrow a severed limb.

Why us? Because zebrafish are pretty special and researchers think we’re easy to work with. First, unlike your standard lab mouse or rat, we lay lots of eggs, producing baby fish that grow up fast. We develop outside our mothers and go from egg to embryo to free-swimming larva in just 3 days (check out this video Exit icon of how we grow, cell by cell, during the first 24 hours). Within 3 months, we’re fully mature.

Not only do zebrafish moms have many babies at the same time, and not only do these babies grow up quickly, but our eggs and embryos are see-through, so scientists can literally watch us grow one cell at a time. We stay mostly transparent for a few weeks after hatching. That makes it super easy for scientists to monitor us for both normal and abnormal development. In fact, scientists have learned how to turn off the genes that give our skin its color. These zebrafish, named casper, after the “friendly ghost” of cartoon fame, stay semi-transparent, or translucent, through adulthood.

And last, but certainly not least, did I mention that we can regenerate? If parts of my body are damaged, even to a significant degree, they can regrow. This holds true for my heart, fins, spinal cord, and even brain tissue. Our regenerative capacity is seemingly unlimited; my caudal fin, for example, can grow back dozens of times. Continue reading “Zebrafish Scrapbook”

Pigment Cells: Not Just Pretty Colors

If you’ve ever visited an aquarium or snorkeled along a coral reef, you’ve witnessed the dazzling colors and patterns on tropical fish. The iridescent stripes and dots come from pigment cells, which also tint skin, hair and eyes in all kinds of animals, including humans. Typically, bright colors help attract mates, while dull ones provide camouflage. In humans, pigment helps protect skin from DNA-damaging UV light.

Researchers study cellular hues not only to decipher how they color our world, but also to understand skin cancers that originate from pigment cells. Some of these researchers work their way back, developmentally speaking, to focus on the type of cell, known as a neural crest cell, that is the precursor of pigment cells.

Present at the earliest stages of development, neural crest cells migrate throughout an embryo and transform into many different types of cells and tissues, including nerve cells, cartilage, bone and skin. The images here, from research on neural crest cells in fish and salamanders, showcase the beauty and versatility of pigment cells in nature’s palette.

Xanthophores
Pigment cells called xanthophores, shown here in the skin of the popular laboratory animal zebrafish, glow brightly under light. Credit: David Parichy, University of Washington.
Melanocytes
Dark pigment cells, called melanocytes, like these in pearl danio, a tropical minnow and relative of zebrafish, assemble in skin patterns that allow the animals to blend into their surroundings or attract mates. Credit: David Parichy, University of Washington.
Fin of pearl danio
Pigment cells can form all sorts of patterns, like these stripes on the fin of pearl danio. Credit: David Parichy, University of Washington.
Salamander skin
Pigment cells arise from neural crest cells. Here, pigment cells can be seen migrating in the skin of a salamander where they will form distinct color patterns. Credit: David Parichy, University of Washington.