Delays in
            <i>Pseudomonas aeruginosa</i>
            quorum-controlled gene expression are conditional

Yarwood, Jeremy M.; Volper, Esther M.; Greenberg, E. Peter

doi:10.1073/pnas.0503728102

Cited by 27 publications

(25 citation statements)

References 43 publications

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“…This indicates that an inhibitor of quorum sensing is present in LB broth and depleted during cell growth. A similar situation was previously reported for Pseudomonas aeruginosa (45). The role of the LuxR homolog AbaR in the activation of abaI in the presence of 3-hydroxy-C 12 -HSL is unknown at present, as repeated attempts to create an abaR null allele have failed for unknown reasons.…”

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confidence: 52%

Isolation and Characterization of an Autoinducer Synthase from Acinetobacter baumannii

et al. 2008

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The opportunistic human pathogen Acinetobacter baumannii strain M2 was found to produce distinct acyl-homoserine lactone (AHL) signals based on the use of an Agrobacterium tumefaciens traG-lacZ biosensor. An A. baumannii gene, designated abaI, was cloned and directed AHL production in recombinant Escherichia coli. The AbaI protein was similar to members of the LuxI family of autoinducer synthases and was predicted to be the only autoinducer synthase encoded by A. baumannii. The primary AHL signal directed by AbaI was identified by mass spectrometry as being N-(3-hydroxydodecanoyl)-L-HSL (3-hydroxy-C 12 -HSL). Minor amounts of at least five additional AHLs were also identified. The expression of abaI at the transcriptional level was activated by ethyl acetate extracts of culture supernatants or by synthetic 3-hydroxy-C 12 -HSL. An abaI::Km mutant failed to produce any detectable AHL signals and was impaired in biofilm development.

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confidence: 52%

Isolation and Characterization of an Autoinducer Synthase from Acinetobacter baumannii

et al. 2008

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“…DNA contamination of RNA samples was assessed by PCR amplification of the P. aeruginosa rplU gene with the primers rplU-for (5Ј-CGCAGTGATTGTTACCGGTG-3Ј) and rplU-rev (5Ј-A GGCCTGAATGCCGGTGATC-3Ј). The rplU gene is commonly used to monitor DNA contamination in P. aeruginosa RNA samples (27,29,68). Agarose gel electrophoresis was used to assess RNA integrity.…”

Section: Methodsmentioning

confidence: 99%

Nutritional Cues ControlPseudomonas aeruginosaMulticellular Behavior in Cystic Fibrosis Sputum

2007

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The sputum (mucus) layer of the cystic fibrosis (CF) lung is a complex substrate that provides Pseudomonas aeruginosa with carbon and energy to support high-density growth during chronic colonization. Unfortunately, the CF lung sputum layer has been difficult to mimic in animal models of CF disease, and mechanistic studies of P. aeruginosa physiology during growth in CF sputum are hampered by its complexity. In this study, we performed chromatographic and enzymatic analyses of CF sputum to develop a defined, synthetic CF sputum medium (SCFM) that mimics the nutritional composition of CF sputum. Importantly, P. aeruginosa displays similar phenotypes during growth in CF sputum and in SCFM, including similar growth rates, gene expression profiles, carbon substrate preferences, and cell-cell signaling profiles. Using SCFM, we provide evidence that aromatic amino acids serve as nutritional cues that influence cell-cell signaling and antimicrobial activity of P. aeruginosa during growth in CF sputum.A key concept in bacterial pathogenesis is the ability of invading pathogens to obtain sufficient carbon and energy from the host for in vivo growth. Although Garber originally proposed the host as a growth medium over 40 years ago (12), the nutritional environment of most infection sites is poorly defined and often inadequately modeled by laboratory growth media. This lack of knowledge, combined with the limited utility of many animal models, provides significant challenges for mechanistic studies aimed at examining host nutrients as mediators of colonization and disease. To overcome these challenges, it is critical both to define the nutritional composition of key infection sites and to study bacterial physiology in the context of in vivo-relevant growth substrates.The heritable disease cystic fibrosis (CF) is an archetype for the development of nutritional models with which to study bacterial pathogenesis. A hallmark of CF disease is the accumulation of large volumes of sputum (mucus) within the lungs, which diminishes the host's ability to clear bacterial infections (17,31). The viscous CF lung sputum provides bacteria with a nutritionally rich growth environment composed of host-and bacterial-derived factors (17, 38). The opportunistic pathogen Pseudomonas aeruginosa chronically colonizes the CF lung, where it often grows to high cell densities in CF sputum (Ͼ10 9 cells/ml sputum). Although many other bacterial species persist and grow in the CF lung, chronic P. aeruginosa infection is likely the most clinically relevant, as it is correlated with declining lung function (17). Mechanistically, P. aeruginosa colonization and progression to chronic infection is poorly understood, although potential contributing factors are high-density growth and enhanced fitness of P. aeruginosa in CF sputum. P. aeruginosa fitness has been linked to nutritional components in CF sputum (39), thus necessitating the development of a versatile model that allows examination of CF sputum nutritional cues.The growth environment impacts several...

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“…Second, mass transfer also can produce nutrient gradients, and the nutritional environment has been shown to influence QS (1,6). For example, iron availability can modulate QS in Pseudomonas aeruginosa (1,6), while other components of the nutritional environment can delay the onset of QS (28). Third, the hydrodynamic environment can affect biofilm density and thickness (2,18,25), which in turn can affect signal gradients.…”

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confidence: 99%

Influence of the Hydrodynamic Environment on Quorum Sensing in Pseudomonas aeruginosa Biofilms

et al. 2007

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Delays in Pseudomonas aeruginosa quorum-controlled gene expression are conditional

Cited by 27 publications

References 43 publications

Isolation and Characterization of an Autoinducer Synthase from Acinetobacter baumannii

Isolation and Characterization of an Autoinducer Synthase from Acinetobacter baumannii

Nutritional Cues ControlPseudomonas aeruginosaMulticellular Behavior in Cystic Fibrosis Sputum

Influence of the Hydrodynamic Environment on Quorum Sensing in Pseudomonas aeruginosa Biofilms

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