"We now see there can be benefits to bacterial shapes that are only seen in a growth environment that is close to the bacteria's natural environment," Gitai said.
"For C. crescentus, the ecology was telling us there is an advantage to being curved, but nothing we previously did in the lab could detect what that was," he said. "We need to not only think of the chemical environment of the bacteria we also need to think of the physical environment. I think of this research as opening a whole new axis of studying bacteria."
While most bacteria grow and divide as two identical "daughter" cells, C. crescentus divides asymmetrically. A "stalked" mother cell anchors to a bacterium's home surface while the upper unattached portion forms a new, juvenile version of the stalked cell known as a "swarmer" cell. The swarmer cells later morph into stalked cells then eventually detach before laying down roots nearby. They repeat the life cycle with their own swarmer cell and the bacterial colony grows.
The Princeton researchers found that in moving water, curvature points the swarmer cell toward the surface to which it needs to attach. This ensures that the bacteria's next generation does not stray too far from its progenitors, as well as from the nutrients that prompted cell division in the first place, Gitai said. On the other hand, the upper cells of straight bacteria which are comparatively higher from the ground are more likely to be carried far away as they are to stay near home.
But the advantage of curvature only goes so far. The researchers found that when the water current was too strong, both curved and straight bacteria were pressed flat against the surface, eliminating t
|Contact: Morgan Kelly|