St. Olaf News

 

Researchers look for clues in mutant bacteria

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St. Olaf students Heena Joo ’16 (seated) and Petra Hahn ’14 (right) are working with Assistant Professor of Biology Lisa Bowers (left) this summer to discover the purpose of a gene they deleted from a common type of bacteria. Using this simple bacteria as a stepping stone could be key in future application to other fields such as embryology and stem cell research.

When researchers at St. Olaf College deleted a single gene from a common type of bacteria, they dramatically altered the cell cycle of the organism. In the process, they created a mutant that had never been studied before.

They’re hoping this research will help scientists better understand what sort of genes control the cell cycle — and for what purpose.

Students in Assistant Professor of Biology Lisa Bowers’ research class first isolated this important gene back in January. The bacterial species they’re studying, Caulobacter crescentus, usually undergoes two phases of its cell cycle. During the first phase, the cells have a flagellum, a tail-like structure that helps them swim and look for food. When the cells enter the second phase, they shed the flagellum and grow a long sticky stalk, which allows them to stick to surfaces.

The students discovered that deleting the novel gene prevented Caulobacter from growing a stalk during the second phase of its life cycle. This provided the basis for spring researchers Jonathon Peterson ’14 and Margret Bradley ’13 and summer researchers Petra Hahn ‘14 and Heena Joo ’16 to examine the characteristics of the Caulobacter crescentus mutant.

The summer team, whose work is part of St. Olaf’s Collaborative Undergraduate Research and Inquiry program, is also working on re-inserting this “stalkless” gene back into the mutant cell through a process called gene complementation.

“To our knowledge, nobody has ever studied this gene before, so part of our summer research is to figure out what it encodes exactly,” says Bowers.

Caulobacter works well as a model organism since its short life cycle is characterized by easy-to-see changes. This gives researchers a simpler model to study than, say, a human cell line. Using this simple bacteria as a stepping stone could be key in future application to other fields such as embryology and stem cell research.

“We’ve isolated a mutant that’s never been discovered before, on a gene that’s never been researched before, and this is real research happening here, at St. Olaf, and that’s really cool,” says Hahn.