Campus / News / Student Research / November 3, 2010

Honors profile: Sara DeMaria

ne of many seniors working on Honors projects this year. The title of her project is “Assessing dictyostelid diversity through culture-dependent and culture-independent assays.”

The Knox Student: That’s an impressive title. What does it mean?

Sara DeMaria: Dictyostelids are a group of species of slime mold, or what are known as social amoebas. They’re single-celled and they live their lives in one place until the bacteria they eat runs out. Then, they come together and form what’s called a slug, which is a stalk and a fruiting body. Under the right conditions, it bursts and releases the spores, and hopefully they can go somewhere where there’s bacteria so they can resume their lives.

Dictyostelids are interesting because they’re one of the few species of anything that demonstrate sacrifice, because the amoebas that become the stalk die. What I’m doing is trying to find out what kinds of dictyostelids are present at Green Oaks.

TKS: How did you come up with your project?

SD: This summer I had a Ford Fellowship and I was working with Assistant Professor of Biology Matthew Jones-Rhoades with two species of dictyostelids. While I enjoyed it, I realized that I wanted to do research with more environmental implications or implications on a larger scale.

My mentor told me about a field called metagenomics, which is essentially taking an environmental sample—soil, water, plant material—and extracting all the DNA from that sample and then sequencing it and figuring out what species are there based on what sequence you get.

TKS: What makes your research important?

SD: Dictyostelids are one of the lesser-known model organisms. If they’re going to continue to be used as an organism for research I feel it’s important that we a) see if this approach works on them and b) make some attempts at cataloging their diversity.

TKS: Model organisms? Does that mean you can generalize from dictyostelids to higher animals, the way you can with lab rats?

SD: Yes. The interesting thing about these amoebas is that they’re kind of at this intermediate place between fungi and animals. By looking at their genes, behaviors, adaptations, etc., we can make a lot of conclusions about how things evolved.

TKS: What do you hope to find?

SD: I hope to find out that my technique does work. Also, in my specific research I am taking samples along a gradient from prairie to forest and I want to find out if along that gradient the composition of species changes.

TKS: What is a gradient, in this context?

SD: When two environments are right next to each other there is a phenomenon called an edge and that edge is where things mingle. If you have a prairie next to a forest, you have pure prairie with prairie species and pure forest with forest species, but where they meet you have a mix of species.

TKS: How are you balancing research and the rest of your life?

SD: It’s been really hard. I’ve had to forgo a lot of my social life, but it’s really just a matter of finding any scrap of time and applying it to the work. I’m lucky that my samples are frozen, so if I need to take two or three days and not work on it, I can do that. But it’s definitely always in the back of your mind.

Maya Sharma

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