Toward this goal, Suns teams sought to measure how much mechanical force the Z-ring applies to rod-shaped bacteria during cell division. The researchers knew that each rod-shaped bacterium possesses, around the inside of its midsection, a belt made of a filamentous protein called FtsZ. Most of the time, this ring is inactive. But when a bacterium cell is healthy and has sufficient food, it seeks to reproduce by dividing in two. When it is time for this to occur, the Z-ring receives a signal and begins to contract. This pinching continues until the rod breaks apart to form two daughter cells.
Suns team gathered data from microbiology labs that are studying cell division and then translated these observations into mathematical equations. The researchers used the equations to create computer simulations of the cell division process, models that yielded a prediction of the Z-ring force: 8 piconewtons. A piconewton is one-trillionth of a newton. One newton is approximately the amount of force needed to lift a baseball in Earths gravity.
The surprise was that the amount of force generated by the Z-ring was so small, Sun said. Most researchers believed a lot more force would be required during the cell division process.
This information could be used, Sun said, by drug developers seeking a way to disable the Z-ring so that harmful bacteria can no longer reproduce. The research has wider implications as well. Our mathematical equations could also be used to help understand how plant and animal cells divide, including human cells, Sun said. Human cells have an actin ring that behaves the same way as a Z-ring. It contracts during division. The mathematical formulas develop
|Contact: Phil Sneiderman|
Johns Hopkins University