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Lookup NU author(s): Professor Nicholas JakubovicsORCiD,
Dr Matthew BashtonORCiD
This is the authors' accepted manuscript of an article that has been published in its final definitive form by Wiley-Blackwell, 2015.
For re-use rights please refer to the publisher's terms and conditions.
Streptococcus gordonii is an oral commensal and an early coloniser of dental plaque. In vitro, S. gordonii is conditionally auxotrophic for arginine in monoculture, but biosynthesises arginine when coaggregated with Actinomyces oris. Here, we investigated the arginine-responsive regulatory network of S. gordonii and the basis for conditional arginine auxotrophy. ArcB, the catabolic ornithine carbamoyltransferase involved in arginine degradation, was also essential for arginine biosynthesis. However, arcB was poorly expressed following arginine depletion, indicating that arcB levels may limit S. gordonii arginine biosynthesis. Arginine metabolism gene expression was tightly co-ordinated by three ArgR/AhrC family regulators, encoded by argR, ahrC and arcR genes. Microarray analysis revealed that >450 genes were regulated in response to rapid shifts in arginine concentration, including many genes involved in adhesion and biofilm formation. In a microfluidic salivary biofilm model, low concentrations of arginine promoted S. gordonii growth, whereas high concentrations (>5 mM arginine) resulted in dramatic reductions in biofilm biomass and changes to biofilm architecture. Collectively, these data indicate that arginine metabolism is tightly regulated in S. gordonii and that arginine is critical for gene regulation, cellular growth, and biofilm formation. Manipulating exogenous arginine concentrations may be an attractive approach for oral biofilm control.
Author(s): Jakubovics NS, Robinson JC, Samarian DS, Kolderman E, Yassin SA, Bettampadi D, Bashton M, Rickard AH
Publication type: Article
Publication status: Published
Journal: Molecular Microbiology
Print publication date: 07/07/2015
Online publication date: 20/05/2015
Acceptance date: 03/04/2015
Date deposited: 01/05/2015
ISSN (print): 0950-382X
ISSN (electronic): 1365-2958
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