Welcome to one of the world's most prestigious microbiology labs. It's one part theater, one part brilliance - all overseen by an aerobics-teaching diva who loves bacteria.

Photographs by Sean McCormick. Photo illustration by Ann E. Cutting.

Bonnie Bassler carries a flask into a small, windowless room and closes the door behind her. She turns off the light. A fluorescent  blue-green glow emanates from the flask,
highligting her hands, tinging her skin. Industrial chemical? Radioactive isotope? The warm, musty odor in the room says no -- only something living could smell like decomposing guppy food. And in a way, that's what this is: It's an oceangoing bacteria called Vibrio harveyi, which lights up when it's present in numbers.

V. harveyi is the bacterium that launched Bassler into a field of microbiology known as quorum sensing - named for bacteria's ability to alert one another when a critical mass of their brethren is nearby - with her own eponymous lab at Princeton University. It's the bacterium that ushered her into the select group of MacArthur Fellows and into the National Academy of Sciences. It's the bacterium that taught Bassler its language.

You could say that Bassler loves V. harveyi. She even loves its funky scent, which works its way into the throat and sinuses, where it lingers. Standing in the dark lab, holding up the luminescent flask, her face lit by her glowing offspring, she might be a parody of a Fra Angelico Madonna and Child.

"Ahhh," she says, inhaling deeply. "Smells like fish poop."