To study this behavior in the lab, Igoshin and Rice co-authors postdoctoral fellow Chunyan Xie and graduate student Haiyang Zhang created a computer program that could analyze thousands of still frames from microcinematic movies of M. xanthus. The movies were created in the laboratory of University of Georgia collaborator and co-author Lawrence Shimkets. The movies showed how M. xanthus streamed together to form "aggregates." One hallmark of the M. xanthus streaming process is that less than half of the aggregates that initially form will survive through the end of the process. The factors that control this ripening are not understood.
In designing their image-analysis application, Igoshin's team had the computer scrutinize every aggregate -- frame-by-frame -- throughout the streaming process. The computer cataloged 33 properties for each aggregate, including things like area, perimeter size,.distance to and size of the nearest neighbor. After all the data were collected, the team ran a statistical analysis to find out if any feature or combination of features could be used to predict which aggregates would eventually win out over their neighbors.
"We found that size mattered most," Igoshin said. "Not size in relation to neighbors, which is something people had previously thought might matter, but size of the aggregate itself. We found that if we answered one question -- is the size of an aggregate beyond a certain threshold -- then we could accurately predict whether the aggregate would survive with 90 percent accuracy."
Igoshin said some of the image analysis methodologies that the team applied to study M. xanthus are similar to ones that Chunyan Xies used for facial recognition ana
|Contact: Jade Boyd|