The cell is the fundamental unit of life. However, cells in nature rarely lead a solitary existence, but rather reside in large communities, much like most of the human population on our planet resides in cities. Even bacteria, which are single cell organisms are predominantly found within communities known as biofilms. This provokes a fundamental question: How much independence does the individual cell retain when it is part of a community? Specifically, does the individual cell, or the community, determine the response to a local perturbation? There is an urgent need to address this question, since a bacterial cell within the biofilm community can be thousand times more drug resistant than the same bacterium living in solitude. Antibiotics typically target biochemical processes within individual cells. Therefore, knowledge on how biological systems balance the need for cellular individuality versus collective coordination would improve strategies to curtail deleterious effects or enhance the beneficial ones. In line with the goals of the NSF, this research exemplifies interdisciplinary research and applies concepts from the field of mathematics and physics to solve a fundamental problem in biology. As such, it will provide an excellent training opportunity not only for the graduate student and postdoc, but also for the many undergraduate and high school students with diverse backgrounds that receive training in the investigator?s laboratory.
The investigator has recently uncovered that bacterial biofilms exhibit global oscillations in protein aggregation and growth. Motivated by this breakthrough, he proposes to develop a prototype microfluidic device in which the response of an individual bacterium can be tracked within large biofilms. The PI will integrate the data collected with a mathematical theory based on the Phase Response Curves that revolutionized the study of circadian rhythms. He will develop a novel microfluidic system that will allow the precise determination. how cells within a biofilm community respond to a local perturbation. The question of individuality versus collective behavior remains unresolved not only in biology, but also across all the physical sciences. The investigator also pursues the unprecedente prediction that the observed relatively long-range (milimeter distances) coordinaton of population behavior is unlikely due to the diffusion of chemical signals, but rather, derives from by radical gases associated with aging bacterial populations.
