Anna Edlund
J Craig Venter Institute, USA
Title: Bacterial community responses at the gene and molecule level during sugar catabolism in highly diverse oral in vitro biofilms
Biography
Biography: Anna Edlund
Abstract
The oral micro-biome representing dental plaque is highly impacted by frequent and drastic pH drops due to the rapid response
of microbial fermentation of dietary carbohydrates. In caries-associated plaque samples, pH remains below the ‘critical level for
demineralization’ for extended periods of time after a carbohydrate pulse, while in health-associated plaque pH recovers. A major
hurdle to understanding the dynamic interactions of oral biofilms and low pH-virulence development associated with caries disease
is the high taxonomic variability of the oral microbiome between individuals. Also, it is extremely difficult to track species and strains
temporally and spatially. To circumvent these major hurdles, we developed an oral in vitro biofilm model system, derived from
human saliva. This biofilm model proved to be reproducible and stable at both taxonomic and functional levels and contained ~130
operational taxonomic units (OTUs), covering 60-80% of the original saliva diversity. In this study we applied this model as a solid
platform to answer fundamental questions of the processes within naturally diverse dental plaque, associated with both health and
disease. We applied a parallel approach of sampling for community mRNA (metatranscriptomics) and secreted small molecules during
sugar fermentation and biofilm formation, to acquire new information on gene transcription activities and metabolite production
in low pH. The biological information captured here reveals highly regulated gene transcription activities and temporal secretion of
both primary and secondary metabolites, of which a few belong to bioactive groups of compounds (e.g. alkaloids, lactones and cyclicdipeptides).