Nature’s Mysteries Revealed with New DNA Libraries
Hundreds of drugs available today were derived from compounds scientists originally found in microbes. The development of these drugs relied on isolating microbial species in pure cultures — that is, cultures containing only a particular species of microbe. But less than 1 percent of the millions of microbial species on Earth have been cultured in a laboratory.
“Many of the antibiotics in our clinical arsenal were discovered from microorganisms isolated from natural environments”, says Auburn microbiologist Mark Liles, “but we have to be smarter about how we discover new antibiotics”.
That’s where microbial community genomics (also known as “metagenomics”) comes in. In metagenomics, the power of genomic analysis is applied to entire communities of microbes, bypassing the need to isolate and culture individual microbial species. Metagenomics gives scientists access to millions of microbes that have not been previously studied.
Liles and his team have made the best of that access. The Liles lab is working on two NIH funded projects. One focuses on characterizing and developing a collection of recently discovered antibiotics; and the second — in collaboration with the Lucigen Corporation — is the creation of new metagenomic libraries.
A recently constructed library contains very large fragments of DNA, larger than have ever before been captured from soil microorganisms. The biosynthetic pathways that encode antibiotics or other drugs – the instructions for a cell to manufacture the drugs – are on very large fragments, so the ability to capture entire pathways on a large fragment of genome is a key to the success of this technology. These metagenomic libraries can be screened to identify antibiotics, as well as other natural products such as enzymes and anticancer drugs, that address important problems in medicine, agriculture, and biotechnology that challenge us today.
Research and Teaching Interests
Environmental microbiology. Community genomics of microbial assemblages, with an emphasis on antibiotic biosynthetic pathways and mobile genetic elements that can confer antibiotic resistance. Also studying biological control agents for disease prevention and probiotic effects in animals and plants. See Liles’ Web site for more detailed information.