Altruism plasticity and byproduct-service exchange in the evolution of
reciprocal cooperation in Escherichia coli
Explaining how cooperative individuals positively assort into a cohesive
community is one of the greatest challenges for evolutionary biology.
Here, we show that in antibiotic culture, many and even all of
Escherichia coli bacteria cells will plastically mutate to be antibiotic
resistant with the increase of antibiotic concentration and then
altruistically protect antibiotic-sensitive individuals from the attack
of antibiotics. A further experiment showed that antibiotic-sensitive E.
coli strain could in turn help reduce the indole produced by the
resistant strain;whistthis metabolic product is harmful to the growth of
the antibiotic-resistant strain but benefits the antibiotic-sensitive
strain by helping turn on the multi-drug exporter to discharge the
antibiotic. A reciprocal cooperation can therefore evolve via a
non-positive exchange between the metabolism byproduct indole of
antibiotic-resistant cells and the indole-aborting service of antibiotic
sensitive cells as unconscious help in nullifying indole side effect of
antibiotic resistant strain.