Bonnie Bassler of Princeton University and the Howard Hughes Medical Institute has revolutionized the way that we think about microbiology. She elucidated the chemical language that bacteria use to communicate through a process called quorum sensing that allows bacteria to count their numbers, determine when they’ve reached a critical mass, and then change their behavior in unison to result in virulence or even bioluminescence. Called everything from a [MacArthur] genius to the bacteria whisperer, Bassler also excels at the art of scientific communication, has dabbled in theater, and many mornings a week leads an aerobics class in Princeton.