For millennia, the baker’s yeast—a humble fungus—has helped humans to bake bread and brew alcoholic drinks. In recent decades, it has also become a darling of laboratory science—it is easy to grow, study, and genetically manipulate, and it provides scientists with important clues about how our own cells work. Now, thanks to Nili Ostrov and colleagues at Columbia University, baker’s yeast is about to begin yet another career—as a biosensor for detecting cholera and other diseases.
Cholera is caused by a bacterium called Vibrio cholerae, which lives in salty water and lashes itself to the shells of small crustaceans. If it finds its way into our drinking supplies, and into human bodies, it can cause severe diarrhea, which can be fatal if left untreated. If such infections aren’t controlled quickly, they can flare into massive epidemics. One, currently going on in Yemen, has already infected 200,000 people and is afflicting 5,000 more every day. Another, which began in Haiti in 2010 and continues to this day, has already affected 7 percent of the country’s population.
Currently, scientists detect V. cholerae by growing the bacterium in Petri dishes—a laborious process that takes a day or two. That’s too slow. To control cholera outbreaks, researchers need faster ways of detecting the bacterial culprits. Ideally, you’d have something that works like a home pregnancy kit—a simple dipstick that would give a clear answer after being dunked in water. The Columbia team has now created a prototype for such a device, using yeast.