Using untargeted and targeted metabolomics methods, the Kujawinski laboratory has analyzed exudates by Ruegeria pomeroyi, a member of the Roseobacter clade within the α-proteobacteria (Johnson et al., 2016). They compare intracellular and extracellular profiles as a function of two growth substrates, propionate, a 3-carbon carboxylic acid and dimethylsulfoniopropionate (DMSP), a quantitatively significant algal osmolyte. The lefthand panel portrays the diffuse oligotrophic ocean with free-living organisms. In contrast, the righthand panel shows dying plankton cells coalescing to form a colloid or particle composed of, and exuding, organic matter. The phytoplankton cells leak DMSP which triggers production of a signaling molecule in R. pomeroyi (orange cells). Once the signaling molecule is present at a sufficient concentration, an array of metabolic shifts occur. (Illustration: Jack Cook, WHOI)



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Last updated May 4, 2017
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