Abstract
Proteomes of acid mine drainage biofilms at different
stages of ecological succession were examined to
understand microbial responses to changing community
membership. We evaluated the degree of reproducibility
of the community proteomes between
samples of the same growth stage and found stable
and predictable protein abundance patterns across
time and sampling space, allowing for a set of 50
classifier proteins to be identified for use in predicting
growth stages of undefined communities.
Additionally, physiological changes in the dominant
species, Leptospirillum Group II, were analysed as
biofilms mature. During early growth stages, this
population responds to abiotic stresses related to
growth on the acid mine drainage solution. Enzymes
involved in protein synthesis, cell division and utilization
of 1- and 2-carbon compounds were more
abundant in early growth stages, suggesting rapid
growth and a reorganization of metabolism during
biofilm initiation. As biofilms thicken and diversify,
external stresses arise from competition for dwindling
resources, which may inhibit cell division of
Leptospirillum Group II through the SOS response.
This population also represses translation and synthesizes
more complex carbohydrates and amino
acids in mature biofilms. These findings provide
unprecedented insight into the physiological changes
that may result from competitive interactions within
communities in natural environments.
