Developmental On-Off Switch Identified in Antibiotic Producing Microbes

An on-off switch in a group of soil microbes called Streptomyces that produce more than two-thirds of the world's naturally derived antibiotic medicines has been identified by researchers who hope that the ability to manipulate the switch can lead to more efficient production of antibiotics. Their hope now would be to see whether it is possible to manipulate this switch to make nature's antibiotic factory more efficient.

The study, appearing August 28 in Cell, found that a unique interaction between a small molecule called cyclic-di-GMP and a larger protein called BldD ultimately controls whether a bacterium spends its time in a vegetative state or gets busy making antibiotics.

Researchers found that the small molecule assembles into a sort of molecular glue, connecting two copies of BldD as a cohesive unit that can regulate development in the Gram-positive bacteria Streptomyces.

"For decades, scientists have been wondering what flips the developmental switch in Streptomyces to turn off normal growth and to begin the unusual process of multicellular differentiation in which it generates antibiotics," said Maria A. Schumacher, Ph.D., an associate professor of biochemistry at the Duke University School of Medicine. "Now we not only know that cyclic-di-GMP is responsible, but we also know exactly how it interacts with the protein BldD to activate its function."

Streptomyces has a complex life cycle with two distinct phases: the dividing, vegetative phase and a distinct phase in which the bacteria form a network of thread-like filaments to chew up organic debris and churn out antibiotics and other metabolites. At the end of this second phase, the bacteria form filamentous branches that extend into the air to create spiraling towers of spores.

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Source-Eurekalert