Speaker
Dr. Chris Dupont
Speaker's Institution
J. Craig Venter Institute
Date
3/6/12
Time
4:00 PM
Location
Anatomy/Zoology Building W118
Mixer Time
3:30 PM
Mixer Location
Anatomy/Zoology Building E112
Additional Information

The Global Ocean Sampling project was initiated in the fall of 2003.  Since then, samples have been collected from over 500 locations in most of Earth’s major oceans and seas.  In parallel, the number of completed microbial genomes numbers in the 1000’s, thus it was sobering to find that only approximately a quarter of the GOS dataset could be associated with a reference genome.   Essentially, many of the most abundant and theoretically important microbes are not cultivated.  To address this shortfall, genomes were assembled directly from the metagenomic datasets, while abundant and uncultivated OTUs were targeted for single cell genomics.    In one study, complete genomes of previously unrecognized clades of the cyanobacterium Prochlorococcus were assembled from stations in the south Pacific.  Both the biogeography and genomic contents of these Prochlorococcus lineages suggest adaptations to regions of the ocean where Fe limits the growth of most other phytoplankton.  In another study, several genomes of the uncultivated SAR86 class of gamma-proteobacteria were attained.  Phylogenomic analyses establish SAR86 as a basal and divergent lineage of gamma-proteobacteria, and the individual genomes display a temperature-dependent distribution. The genomes contain an expanded capacity for the degradation of lipids and carbohydrates acquired using a wealth of tonB-dependent outer membrane receptors. Like the abundant planktonic marine bacterial clade SAR11, SAR86 exhibits metabolic streamlining, but also a distinct carbon compound specialization, possibly avoiding competition.   Both studies provided information potentially valuable to cultivation efforts, and a substantial amount of unclassified metagenomic data was placed in ecological and evolutionary context.

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