Dynamic responses of Bacteroides thetaiotaomicron during growth on glycan mixtures. Issue 5 (5th May 2013)

• Record Type: Journal Article
• Authors: Rogers, Theresa E.; Pudlo, Nicholas A.; Koropatkin, Nicole M.; Bell, Joshua S. K.; Moya Balasch, Monica; Jasker, Kevin; Martens, Eric C.
• Is Part Of: Molecular microbiology. Volume 88:Issue 5(2013)
• Page Start: 876
• Page End: 890
• Publication Date: 2013-05-05
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12228
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p> <italic>B</italic> <italic>acteroides thetaiotaomicron</italic> (<italic>Bt</italic>) is a human colonic symbiont that degrades many different complex carbohydrates (glycans), the identities and amounts of which are likely to change frequently and abruptly from meal‐to‐meal. To understand how this organism reacts to dynamic growth conditions, we challenged it with a series of different glycan mixtures and measured responses involved in glycan catabolism. Our results demonstrate that individual <italic>Bt</italic> cells can simultaneously respond to multiple glycans and that responses to new glycans are extremely rapid. The presence of alternative carbohydrates does not alter response kinetics, but reduces expression of some glycan utilization genes as well as the cell's sensitivity to glycans that are present in lower concentration. Growth in a mixture containing 12 different glycans revealed that <italic>Bt</italic> preferentially uses some before others. This metabolic hierarchy is not changed by prior exposure to lower priority glycans because re‐introducing high priority substrates late in culture re‐initiates repression of genes involved in degrading those with lower priority. At least some carbohydrate prioritization effects occur at the level of monosaccharide recognition. Our results provide insight into how a bacterial glycan generalist modifies its responses in dynamic glycan environments and provide essential knowledge to interpret related metabolic behaviour <italic>in vivo</italic>.</p> </abstract>