The Genomic Revolution has always held promise in two areas: to provide insights into biological change over time, and to provide insights about population migrations and mixtures. But while ancient DNA studies over the last 8 years have been a runaway success with regard to revealing human demographic history, they have so far revealed little in terms of clear insights...
To paraphrase Louis Pasteur, sometimes luck favors the prepared mind, as when Alexander Fleming discovered penicillin by noticing that mold growing accidentally in his lab seemed to kill bacteria. At other times, new instruments offer unanticipated revelations: Galileo trained his telescope on Jupiter and...
The shape of bacteria is determined by their cell wall, a crosslinked macromolecule that holds them in shape. To grow in defined shapes, or divide half, bacteria must add material into this structure in a spatially controlled manner. The activity of the enzymes that build the cell wall is regulated by small dynamic filaments, homologs of eukaryotic cytoskeletal proteins. We study the emergent actions of these polymer/enzyme systems by observing their in vivodynamics while conducting chemical and genetic manipulations. We have found that the polymers controlling cell elongation... Read more about MCB Seminar -- "A contrasting tale of dynamics: how two different polymers define the shape of bacteria and cut them in half" by Ethan Garner (Harvard)
Most bacteria live in surface-attached communities called biofilms, in which nutrient gradients and physical forces determine where individual cells grow and move. These physical aspects of the growth process affect the evolutionary dynamics, i.e., the fates of spontaneous and pre-existing mutations, in biofilms, yet most experimental evolution in the lab is concerned with bacteria grown in shaken culture flasks. Thus, to be able to predict, e.g., the evolution of antibiotic resistance, we need quantitative models of the stochastic dynamics of...
The dynamics of two coupled resonators have stimulated investigations for well over a century. We take a fresh look at this problem using equivalent circuits, which give a complete understanding largely by inspection.
We show one property, whereby the induced voltage on a load attached to one resonator remains constant with changing coupling coefficient when the other resonator is driven by an independent sinewave source, provided its frequency tracks the changing mode. This is developed into an inductively coupled system that supplies about 10 mW to power...