Straightening up for life in a biofilm.

Since our eyes were opened to the microscopic world centuries ago, microbiologists have been dazzled by the incredible diversity of shapes and sizes adopted by bacteria (1). Given this dizzying morphological potential, it is remarkable that most species gravitate to a particular shape. It is tempting to speculate that the “one species, one form” paradigm reflects the selective benefits of the chosen shape in the natural environment of each species. But how is cell shape determined? And does a given shape truly confer a fitness advantage? Although these questions are often asked, definitive answers have remained elusive. Vibrio cholerae , the pathogen responsible for the diarrheal disease cholera, typically adopts a characteristic comma (curved) shape. In PNAS, Fernandez et al. (2) report that cellular curvature in V. cholerae is regulated by the second messenger cyclic dimeric guanosine monophosphate (c-di-GMP), whose levels are known to regulate cell motility (3) and biofilm formation (4). Fernandez et al. further suggest that c-di-GMP regulation of cell shape may provide an advantage during environmental transitions in which motility and formation of a sessile biofilm are alternately beneficial (4).\n\nUnlike most model bacteria that are not typically considered shape shifters, the typical shape of V. cholerae cells changes over the course of a batch culture. In 1928, Arthur Henrici (5) published a tour-de-force quantification of the shapes of thousands of V. cholerae cells sampled from a culture as it grew from lag phase to exponential phase and then to … \n\n[↵][1]1To whom correspondence may be addressed. Email: kchuang{at}stanford.edu.\n\n [1]: #xref-corresp-1-1