CC Professors Kristine Lang and Phoebe Lostroh are studying Acinetobacter baylii, a non-pathogenic soil bacteria, to understand how it takes in DNA, leading to genetic changes.
Bacteria have only one parent so they don’t undergo genetic variation the way humans do, explained Lostroh, a microbiologist. She said various bacteria use one of three methods of “horizontal gene transfer” and one of those methods is “competence,” or the ability to uptake DNA from the environment, which is not well understood.
“Competence is the least common method but many bacteria that make us sick use this and it seems to be important in helping them prepare to attack the human body and resist antibiotics. It would be helpful if we knew more about this mechanism,” said Lostroh.
That’s where Lang, a physicist, comes in. Her expertise with the physics research tool Atomic Force Microscopy (AFM) [see definition at top] led the two scientists to team up to see if they could get detailed images of bacteria. When that proved successful in 2009, they moved on to see if they could visualize competence — get images of the tiny machine a bacteria cell makes to bring in DNA — as a way to better understand what is going on.
“We think the bacteria build an appendage to bring DNA in through a pore on its outer membrane. We’d like to get a picture of these pores or competence appendages in an intact bacterium — something that hasn’t been done before,” Lang said. They also hope to get the first-ever images of these cells while alive. The National Science Foundation grant will allow them to upgrade the college’s AFM to make such imaging possible.
“We are really excited to try to find out if these little cells make these appendages on purpose, and perhaps in response to the presence of DNA,” Lostroh said.
Another part of their work is trying to determine which genes in the bacteria are required for competence. To do this, they are studying cells without specific genes one by one. “Students in our FYE class took pictures of different mutants and we found out the different genes changed the shape of the bacteria in numerous ways,” Lang explained.