Are you going to eat that?

July 14, 2014 — Campus Highlights



eggplantFlickrCCMaybe it’s the way she pushes dietary fiber on them. For whatever reason, students assume that Theresa Rogers, an assistant professor of biology, is a vegetarian. But if they ask about it, her reply cheers the meat eaters: “I respect plants as much as I do animals.”

Rogers is full of surprises like that. At first you think she’s going to keep after you about the fiber. Getting plenty of it, she says, regularly and from a variety of sources, will promote equilibrium in your gut and, given time, will mean less uncomfortable gas. Can you beat that? Yes, in fact, you can. Fiber reduces the risks of ills small and large, like obesity and diabetes and constipation and heart disease.

So now you’d like some fiber, right?

Well, it’s hardly that simple, says Rogers, eyebrows high. How do you intend to digest it? You’re a human with a few alimentary enzymes that generally work on simple sugars and starches. Seriously, what are you going to do if you ingest a lot of highly branched plant cell wall polysaccharides? Forget it. Order the steak.

Right about then, the school bell rings and we’re ready to learn. It so happens that Rogers, who came to Cal Lutheran this year after a postdoc at the University of Michigan and a visiting professorship elsewhere, has already established herself as an authority on how we process fiber in the gut. She was one of three principal authors to publish on the subject this spring in the leading scientific journal Nature.

The key, if you haven’t guessed, is gut bacteria. It’s true that people don’t have the ability to break down many complex carbohydrates, but the trillions of bacteria that live in every healthy individual do, and Rogers et al. show at the molecular level how one friendly gut dweller known as Bacteroides ovatus goes about it.

For her part of the study, Rogers busily produced bacterial mutants with deleted genes, like a computer programmer intentionally writing glitches into code. This allowed her to determine the roles of eight individual genes as well as the larger genetic locus in the degradation of xyloglucan, a common complex sugar.

Understanding how gut bacteria reduce complex sugars to mush will have practical applications beyond your choice of fruits and vegetables. As a master’s student, Rogers looked at how the same process might be used to convert sugar beet pulp into ethanol for fuel. Then growers wouldn’t pay for such agricultural waste products to be hauled off to landfills, and we could all have our corn for the table.


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