After giving us lifetimes of plagues, colds, and athlete’s foot, microbes are being recruited and transformed to fight disease—and help us in other ways, too. The technology emerging from the Human Genome Project has made sequencing DNA one-fiftieth the cost of a decade ago and given geneticists a wealth of information, so that a standard laboratory organism can be altered with relative ease. With some tweaks to their genetic code, microbes can be turned into tiny workhorses:

Yeast

Image courtesy of CDC

Microbes vs. Disease, Round I
Bacteria and yeast, which cause so many diseases, may soon help cure illness: scientists can use microbes as mini-factories to produce cheap and effective drugs.

For example, the drug artemisinin is almost 100 percent effective at treating malaria, but it is also pricey, leaving the African and South American countries that need it most unable to afford it. All that could change if using bacteria and yeast lets scientists bypass expensive laboratory processes to synthesize the drug. Berkeley researchers have already genetically engineered yeast to produce the chemicals that are basic ingredients of the drug.


Microbes vs. Disease, Round II
Lactobacillus, a natural resident of the vaginal and gastrointestinal tracts, defends against urinary infections and diarrhea. Now, thanks to Osel, a bacterial therapeutics company, the microbe may be genetically enhanced to manufacture proteins that target and attack HIV.

Adenovirus

Image courtesy of National Cancer Institute

Microbes vs. Disease, Round III
By modifying a few genes in adenoviruses (which bring us the common cold), scientists at Introgen Therapeutics are engineering weapons against cancer. Special strains of the adenovirus, the researchers say, have been altered to deploy anticancer genes within tumors, killing cancer cells while leaving healthy ones unscathed.

Microbes vs. Disease, Round IV
Your typical vaccine is engineered to prevent trouble before it starts. Yet NIH scientists have developed a vaccine that targets tumors that are already formed. In recent tests, genetically engineered yeast in the vaccine delivered a common tumor protein that stimulated the immune systems of mice, thereby destroying tumors. The results of these animal trials may eventually help patients with colon, rectum, stomach, breast, or lung cancer.