Research overview

Microbial communities are shaped by interactions within and among species.

Microbes often cooperate with neighbors to exert collective control over their environments. Biofilms shield bacteria from harsh environments, algal toxins collectively eliminate competitors, and multi-celled aggregates defend against predators.

However, Darwinian competition among cells may select against cooperation--even when entire populations or communities depend on it. Selection for selfish mutants that exploit the ‘public good’ (i.e. common resources) without reciprocating may threaten secreted products involved in polysaccharide hydrolysis (yeast invertase and bacterial chitinases), iron acquisition (bacterial siderophores), and the elimination of competitors (bacterial toxins).

Fast growth and large populations allow microbes to quickly adapt to changing environments. Bacteria and yeast can double in < 1 hour and exceed densities of 100 million cells per milliliter under favorable laboratory conditions.

Rapid evolution is a crucial aspect of microbial community responses to environmental change with far-ranging practical implications for medicine, agriculture, industry and environmental protection.