Koehler's movie clearly shows hyphae boring through the walls of macrophages. Antifungal drugs against Candida have only limited effectiveness. The most effective one comes with such toxic side-effects that many patients quit taking it. We need to understand how the fungus switches forms so we can develop new ways to fight it. One approach involves gene knockouts.
Researchers knock out, or mutate, genes they believe to be responsible for a microbe's virulence.
If offspring of the bug lack the ability to produce disease, this means that the mutated gene lies at the core of making the microbe infectious. Such experiments are particularly difficult with Candida , however. Fortunately, Gerald Fink of the Whitehead Institute spent many years studying the genetics of a related fungus, Saccharomyces cerevisiae , the yeast that makes bread rise. The genes of these two fungi are so alike that finding how to turn off the shape switch in one should work in the other. Once the switch is off, the researchers reasoned, Jekyll could not turn into Hyde.