A joint study of exotic microbiota community by a team of Russian and US scientists, including researchers from Skoltech Life Sciences Center, has been published in the Proceedings of National Academy of Sciences (USA). The authors performed ultrahigh-throughput functional profiling of oral microbiota of a Siberian brown bear. The team used a new ultrahigh-throughput microfluidic droplet method to screen for microbes from bear microbiota restricting the growth of pathogenic bacterium Staphylococcus aureus. This method allowed to package bacterial cells from a sample under study in individual emulsion droplets together with S. aureus cells. Following the cocultivation, droplets were sorted to pick those with little or no S. aureus cells.
This method allowed the authors to isolates a Bacillus pumilus strain producing amicoumacin, an antibiotic restricting S. aureus growth.
The authors also report that B. pumilus utilizes a new mechanism to protect itself from amicoumacin based on a sophisticated system of switching between deactivation and activation of amicoumacin activity. It is controlled by phosphorylation and dephosphorylation performed by kinase AmiN and phosphatase AmiO, respectively. Analyzing the resistance of different bacteria species to amicoumacin revealed that many representatives of human gut microbiota are susceptible to this compound. Hence, amicoumacin-producing B. pumilus may hold promise as a probiotic for controlled remodeling of human gut microbiota.