Listening to Bacteria

By studying microbial communications, Bonnie Bassler has come up with new ways to treat disease

"Bacteria can talk to each other," says Bonnie Bassler. "Not only can they talk, but they are multilingual." And she knows how to speak their languages. (Richard Schulman)
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Thomas Silhavy, a microbiologist at Princeton who headed the faculty committee that hired Bassler 16 years ago (“I hit a home run,” he says of hiring her. “I hit it out of the park”), is among those with high hopes for eventual spinoffs from quorum-sensing studies. “Of course, it’s always a big, multimillion-dollar challenge to turn basic research into an FDA-approved drug,” he says. “But I think there’s a very real chance this approach will work and give us new tools for intervening in particular diseases.” He cites the case of cystic fibrosis, a congenital disorder in which mucus builds up in the lungs and hosts colonies of bacteria called pseudomonas. Infections that normal adults would readily brush away can fulminate for years in cystic fibrosis patients, until one day the chronic turns virulent and overwhelms the body: uncontrollable pseudomonas infection is a major cause of death among people with the disease. Scientists have traced the onset of virulence to the release of quorum-sensing molecules, the chemical messengers that incite the bacteria to begin operating as a group. In theory, Silhavy says, a drug that blocked the pseudomonal calls to mayhem could prove invaluable in the treatment of the devastating disorder.

Bassler and other researchers have identified a number of molecules that disrupt quorum sensing in test-tube experiments with pseudomonas and cholera bacteria; the test molecules seem to protect worms exposed to the virulent microbes. Bassler even tried her hand at drug development with a start-up company a few years ago. The effort foundered, and she is the first to concede that a medication based on the approach is probably a decade or more away. Nevertheless, the possibility of her work someday being translated from the lab bench to the bedside is part of her ongoing inspiration.

“We’re scientists, we’re curious about how nature works, but we’re also do-gooders,” she says. “It’s fantastic to think that the same experiments we’d do to understand how information gets into cells could have a practical side to them, too.”

It’s a sunny Saturday in Philadelphia, and outdoors, in a park, is where most people might choose to be. Yet the lecture hall at the Wagner Free Institute of Science, with its dim amber lighting, wooden chairs, dried blowfish, human skulls and other Victorian bric-a-brac, is full of people mesmerized by the woman up front, who seems to be carrying her own piece of sun. Bassler’s communication skills are not confined to divining petri dish dishings. She is a dynamo of a public speaker, who regularly dazzles both professional and lay audiences like this one with her vivid descriptions of microbial politics. “She can be very charismatic, but with just enough geekiness to let you know she’s a serious scientist,” says Stephen Winans of Cornell University. People love her dry humor and her blend of merry diva grandeur and aw-shucks insistence that she is just an “imposter” who does “genetics for dopes.”

“Bacteria are the oldest organisms on earth,” Bassler booms from the stage. “They’ve been here for four billion years. They make up 50 percent of the biomass of the earth and nearly 100 percent of its biodiversity.”

If you think bacteria, you probably think disease, putrefaction and germs, and reach for your hand sanitizer. Bassler wants to set you straight. “You live in intimate association with bacteria, and you couldn’t survive without them,” she says. Trillions of human cells make up the human body, but there are at least ten times that number of bacterial cells in you or on you. You are, at best, only 10 percent human. Bacteria coat your skin in an ultrathin protective armor, which helps keep harmful microbes at bay. The bacteria in your gut make vitamins K and B12. You like lettuce? Your intestinal flora gamely generate enzymes so you can digest it. It’s a happy trans-taxa tit-for-tat affair. For bacteria, “it’s the good life, it’s fat city” to dwell in the rich environs of a human being, Bassler says. It’s much better, she goes on, than striking out on their own “in a puddle or free-living in the ocean. Those are nutrient deserts compared to us.” Bacteria may be microscopic—three million can fit onto a pinhead—but they are not invisible. The next time you visit the Grand Canyon and your heart soars at the splendid strawberry-rhubarb striations of rock, take a moment to thank the makers. “Bacteria mineralized the rocks, they deposited the iron,” Bassler says. “They made the geology we see.”

Bassler lives not far from the Princeton campus with her husband, Todd Reichart, and their cat, Spark. Reichart, 48, is an actor and Web page designer. Their 1915 house is compact and elegant and the rooms are all painted different bright colors. “We’re not afraid of color,” Bassler says, “and color is something we agree on.” The two have what a friend describes as a “playfully sparring” relationship. She complains he’s a slob. He complains she doesn’t listen. “Are you still here?” she says, glaring at him. “Don’t you have somewhere to be?” Sorry, Bonnie, he says. “I’m a festering fact of your life.” But when he does finally leave for the evening, she says, “We really do enjoy being together and doing things together. Todd is my biggest fan.” They tried to have children, but it didn’t happen. “It’s not like there’s a void,” she says. “I’m a happy person. He’s a happy man. We have an amazingly rich life, and I have all these kids in my lab.”

Bassler grew up in Miami and later in Danville, California, with her businessman father, stay-at-home mother, older sister, Elissa, and younger brother, Rod. She had Barbie dolls; she was also a jock. “I was a huge athlete as a kid,” she said. “I was on every sports team.” She was a good student as well, and when she slacked off, her mother nudged her back in line. “She would tell me that when she was in college, a woman could only be one of two things, a teacher or a nurse,” says Bassler. “But you, she’d say, you can be anything you want.” Seeing that Bonnie loved animals, her mother found her a volunteer position at a zoo in Miami. “I got to be in there with the camels, operate on a lion,” said Bassler. “It was the coolest job in the world.” Later her mother helped her secure a position at a Kaiser Aluminum facility near Danville, testing bauxite samples from mines. “That’s how I put myself through college,” says Bassler. “I found that I loved working in a lab.” She attended the University of California at Davis and decided to major in biochemistry.

Bassler was just 21 years old when her mother was diagnosed with meta­static colon cancer. Three months later, at the age of 46, she died. The loss is a void that Bassler can’t seem to seal. “I’m older now than she was,” says Bassler, her eyes rimmed with tears. “God, what a rip-off.”

“I wish I could tell her that all the yelling at me to study and setting the timer when I was practicing piano was worth it,” she says. “I wish I could tell her how great this life is.”


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