Microbes have long been an invaluable source of new drugs. And to find more, we may have to look no further than the ground beneath our feet.
Researchers at The Rockefeller University have shown that the dirt beneath New York City teems with our tiny allies in the fight against disease. In soil collected from city parks, the team dug up genetic evidence of bacteria capable of producing a wide range of compounds whose potent effects might be harnessed as medicines. Their work is described in the Proceedings of the National Academy of Sciences.
"By sequencing and analyzing genes within soil samples, we found the genetic instructions for making a wide range of natural products that have the potential to become treatments for various conditions, from cancer to bacterial or fungal infections, or that are already being used as drugs," says senior author.
"The sheer diversity we saw suggests there are many more potentially valuable compounds out there awaiting discovery--even in a place as mundane as urban soil," senior author adds.
Because soil is crammed with competing microbes, it is a rich source of such microbe-derived medicines. However, only a fraction of soil bacteria can be grown in the lab, severely limiting scientists' ability to exploit them. Researchers avoid this problem by looking directly at the bacterial DNA in soil. Within these sequences, the researchers can identify the instructions for making molecules that interest them.
The researchers compared their samples to those from known nonribosomal peptides and polyketides, two families of compounds to which many therapeutic molecules previously isolated from bacteria belong.
As it turns out, the city's diversity extends down into its soil. For instance, a single sample from Prospect Park in Brooklyn harbored genes that likely encode 25 molecules that have been studied for potential use as antibiotics and other types of medicines. Meanwhile, a set of 11 representative compounds discovered elsewhere around the world--such as the antibiotic erythromycin from the Philippines and the antifungal agent natamycin from South Africa--are encoded by gene clusters that were observed within the city parks' soil.
The most important finding, say the scientists, is the abundance of unfamiliar genes.
Medicine-making microbes in New York City soil!
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