Toward a biomechanical understanding of whole bacterial cells.

Following decades of research in genetics and biochemistry, the basic metabolism of bacteria is now well understood. In addition to core metabolism, however, bacterial cells also perform a number of mechanical tasks such as maintaining a characteristic shape, moving within their environment, segregating their genome, and dividing. Major advances in imaging technologies including fluorescence light microscopy (fLM) and electron cryotomography (ECT) have provided new insight into the bacterial ultrastructures that accomplish these tasks. It is now clear, for instance, that bacteria are highly organized, possessing cytoskeletons, specifically arranged genomes, internal compartments, and carefully positioned macromolecular machines. These structures and their functions are reviewed here in the form of a progress report toward a complete biomechanical understanding of a generalized bacterial cell. The goal of eventually integrating genetic, biochemical, imaging, and biophysical data into spatially explicit, mechanically predictive models of whole cells is highlighted.