Integration of metabolic and quorum sensing signals governing the decision to cooperate in a bacterial social trait Journal Article


Authors: Boyle, K. E.; Monaco, H.; Van Ditmarsch, D.; Deforet, M.; Xavier, J. B.
Article Title: Integration of metabolic and quorum sensing signals governing the decision to cooperate in a bacterial social trait
Abstract: Many unicellular organisms live in multicellular communities that rely on cooperation between cells. However, cooperative traits are vulnerable to exploitation by non-cooperators (cheaters). We expand our understanding of the molecular mechanisms that allow multicellular systems to remain robust in the face of cheating by dissecting the dynamic regulation of cooperative rhamnolipids required for swarming in Pseudomonas aeruginosa. We combine mathematical modeling and experiments to quantitatively characterize the integration of metabolic and population density signals (quorum sensing) governing expression of the rhamnolipid synthesis operon rhlAB. The combined computational/experimental analysis reveals that when nutrients are abundant, rhlAB promoter activity increases gradually in a density dependent way. When growth slows down due to nutrient limitation, rhlAB promoter activity can stop abruptly, decrease gradually or even increase depending on whether the growth-limiting nutrient is the carbon source, nitrogen source or iron. Starvation by specific nutrients drives growth on intracellular nutrient pools as well as the qualitative rhlAB promoter response, which itself is modulated by quorum sensing. Our quantitative analysis suggests a supply-driven activation that integrates metabolic prudence with quorum sensing in a non-digital manner and allows P. aeruginosa cells to invest in cooperation only when the population size is large enough (quorum sensing) and individual cells have enough metabolic resources to do so (metabolic prudence). Thus, the quantitative description of rhlAB regulatory dynamics brings a greater understating to the regulation required to make swarming cooperation stable. © 2015 Boyle et al.
Journal Title: PLoS Computational Biology
Volume: 11
Issue: 6
ISSN: 1553-7358
Publisher: Public Library of Science  
Date Published: 2015-06-23
Start Page: e1004279
Language: English
DOI: 10.1371/journal.pcbi.1004279
PROVIDER: scopus
PMCID: PMC4477906
PUBMED: 26102206
DOI/URL:
Notes: Article -- Export Date: 3 February 2016 -- Source: Scopus
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  1. Joao Debivar Xavier
    97 Xavier
  2. Maxime Jean-Marie Deforet
    10 Deforet
  3. Kerry Eileen Boyle
    7 Boyle
  4. Hilary Taylor Monaco
    4 Monaco