"A flock can keep moving in the same direction for times much longer than the lifetime of any individual member," said Toner, a member of the UO Institute of Theoretical Science and a professor in the physics department. "Individuals are being born and dying but their direction and motion can persist much longer than the lifetime of any individual creature."
Secondly, he added, the density changes of such a "mortal flock" -- where some members are leaving by death and joining by birth -- create persistent but predictable fluctuations. "Birth and death are very important in microbiological flocks, such as swarms of bacteria or in collections of self-propelled molecules that flock in most living cells."
This fundamental new knowledge already is applicable to understanding the movement of molecules within cells -- in particular, mitotic spindles that launch the machinery of cell development and division, Toner said.
In mitotic spindles, individual molecules live for only about 20 minutes, but spindles live and continue their work for days, he said. "The motion continues as dead molecules are replaced by newly synthesized molecules, as well as by molecules which immigrate in to take their places."
Through the application of his new theory to the study of mitotic spindles, Toner said, it may be possible to design specifically targeted cancer therapies that, unlike current chemotherapies, would only kill aberrant, or diseased cells, and allow desirable, healthy ones to live. "In reality, such applications are a long wa
|Contact: Jim Barlow|
University of Oregon