New class of antimicrobials discovered in soil bacteria

Researchers have discovered toxic protein particles, shaped like umbrellas, that soil bacteria known as Streptomyces secrete to squelch competitors, especially others of their own species.

The umbrella toxin proteins are the latest example of these bacteria's varied, combative strikes on their microscopic rivals. The crowded, diverse bacteria communities in which they live are a melee of antimicrobial attacks, counterattacks, and defenses.

Ironically, many clinically used antibiotics are derived directly from, or are inspired by, molecules that bacteria use against each other in their natural habitat. Streptomyces' chemical weaponry against their competitors is one of the richest sources of such molecules. Among them is the common, broad-spectrum drug streptomycin.

What makes these newly detected antibacterial toxins different is that, unlike the Streptomyces' small-molecule antibiotics, umbrella toxins are large complexes composed of multiple proteins. They are also far more specific in the bacteria they target.

The authors of the paper speculate that these properties of umbrella toxins explain why they escaped discovery for more than 100 years of research on toxins produced by Streptomyces.

Zdroj obrázku: Angela Gao.