The impaired quorum sensing response of MexAB-OprM efflux pump overexpressing mutants is not due to non-physiological efflux of 3-oxo-C12-HSL
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PROVIDER: PRJNA644728 | ENA |
REPOSITORIES: ENA
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Project description:Multidrug (MDR) efflux pumps are ancient and conserved molecular machineries with relevant roles in different aspects of the bacterial physiology, besides antibiotic resistance. In the case of the environmental opportunistic pathogen Pseudomonas aeruginosa, it has been shown that overexpression of different efflux pumps is linked to the impairment of the quorum sensing (QS) response. Nevertheless, the causes of such impairment are different for each analyzed efflux pump. Herein, we performed an in-depth analysis of the QS-mediated response of a P. aeruginosa antibiotic resistant mutant that overexpresses MexAB-OprM. Although previous work claimed that this efflux pump extrudes the QS signal 3-oxo-C12-HSL, we show otherwise. Our results evidence that the observed attenuation in the QS response when overexpressing this pump is related to an impaired production of alkyl quinolone QS signals, likely prompted by the reduced availability of one of their precursors, the octanoate. Together with previous studies, this indicates that, although the consequences of overexpressing efflux pumps are similar (impaired QS response), the underlying mechanisms are different. This ‘apparent redundancy' of MDR efflux systems can be understood as a P. aeruginosa strategy to keep the robustness of the QS regulatory network and modulate its output in response to different signals.
2021-10-25 | GSE153996 | GEO
Project description:We worked with microarrys analysis in presence of 3-oxo-C12-HSL molecule to analyze the profile of the genes implicated in the Quorum Quenching network in A.baumannii clinical strains. Interestingly, only 13 genes were overexpressed under 3-oxo-C12-HSL molecule being the most level a gene which encodes an Alpha/beta hydrolase enzyme (5.01). The 46.15% of the genes overexpressed were implicated in the synthesis of the acyl-homoserine lactones (AHLs).
2017-06-12 | GSE87009 | GEO
Project description:Quorum-sensing (QS) is a cell-cell communication system that controls gene expression in many bacterial species, mediated by diffusible signal molecules. While the intracellular regulatory mechanisms of QS are often well-understood, the functional roles of QS remain controversial. In particular, the use of multiple signals by many bacterial species poses a serious challenge to current functional theories. Here we address this challenge by showing that bacteria can use multiple QS signals to infer both their social (density) and physical (mass-transfer) environment. Analytical and evolutionary simulation models show that the detection of and response to complex social/physical contrasts requires multiple signals with distinct half-lives and combinatorial (non-additive) responses to signal concentrations. We test these predictions using the opportunistic pathogen Pseudomonas aeruginosa, and demonstrate significant differences in signal decay between its two primary signal molecules as well as diverse combinatorial responses to dual signal inputs. QS is associated with the control of secreted factors, and we show that secretome genes are preferentially controlled by synergistic M-bM-^@M-^XAND-gateM-bM-^@M-^Y responses to multiple signal inputs, ensuring the effective expression of secreted factors in high density and low mass-transfer environments. Our results support a novel functional hypothesis for the use of multiple signals and, more generally, show that bacteria are capable of combinatorial communication. The two primary signal molecules of P. aeruginosa are the homoserine lactones N-(3-oxododecanoyl)-L-homoserine lactone (3-oxo-C12-HSL) and N-butyryl-homoserine lactone (C4-HSL). Effects of the different signal molecules was assessed using a double QS synthase mutant of Pseudomonas aeruginosa PAO1 lasI/rhlI grown at 37M-BM-0C in 25 ml LB broth and 250 ml flasks with shaking at 200 r.p.m. in four treatments, each with a replicate: (a) no addition; (b) 3-oxo- C12-HSL; (c) C4-HSL; and (d) both 3-oxo-C12-HSL and C4-HSL.
2014-03-04 | E-GEOD-55110 | biostudies-arrayexpress
Project description:The human opportunistic pathogen Pseudomonas aeruginosa orchestrates the expression of many genes in a cell density-dependent manner by using a molecular communication system referred to as quorum sensing (QS). This bacterium uses an intricate network of regulators and QS molecules known as autoinducers. Among these autoinducers are two acyl-homoserine lactones (AHL) involved in QS circuits which modulate virulence factors production, biofilm formation, and antimicrobial sensitivity. Disrupting QS, a strategy referred to as quorum quenching (QQ), is a promising approach to modulate virulence while not directly challenging bacterial survival. For P. aeruginosa, QQ can be achieved using exogenous AHL-degrading lactonases. However, the importance of enzyme specificity on quenching efficacy has never been investigated. Here, we used two lactonases both targeting the signal molecules N-(3-oxododecanoyl)-L-Homoserine lactone (3-oxo-C12 HSL) and butyryl-homoserine lactone (C4 HSL) albeit with different efficacy on C4 HSL. Interestingly, both lactonases similarly decreased the concentrations of AHL and comparably impacted the expression of AHL-based circuits. Conversely, strong variations were observed in Pseudomonas Quinolone Signal (PQS) regulation. Both lactonases were then found to decrease virulence factors production and biofilm formation in vitro, albeit with different efficiencies. Unexpectedly, only the lactonase with substrate preference for 3-oxo-C12 HSL was able to inhibit P. aeruginosa pathogenicity in vivo in an amoeba infection model. Similarly, large variations between lactonases were observed in proteins involved in antibiotic resistance, biofilm formation, virulence and diverse cellular mechanisms. This global analysis provides the first evidence that QQ enzyme specificity is crucial to modulate QS-associated behavior in P. aeruginosa PA14.
2020-05-27 | PXD017421 | Pride
Project description:Repurposing bioactive aporphine alkaloids as efflux pump inhibitors
| PRJNA416141 | ENA
Project description:We examined whether the budding yeast Saccharomyces cerevisiae can sense chemical signals from prokaryotes, specifically a variety of quorum sensing molecules from different bacteria species and from Candida albicans. We found that only N-acyl-3-oxo-dodecanoyl homoserine lactone (C12) from the opportunistic human pathogen Pseudomonas aeruginosa induces a stress response in yeast. Microarray experiments were performed in order to continue investigating the stress response. We treated S. cerevesiae (WT strain W303) with N-(3-oxo-dodecanoyl) homoserine lactone (C12), a quorum sensing molecule of Pseudomonas aeruginosa, which we found causes a stress response using a GFP reporter for HSP-12. Treatment conditions: 100 uM C12, 100 uM C12-lactam (control: synthetic analogue of C12 that is inactive in P. aeruginosa), DMSO (control: solvent), and 0.3 mM H2O2 (for comparison to oxidative stress).
2020-03-02 | E-MTAB-4802 | biostudies-arrayexpress
Project description:In this report, we investigated oxo-C14-HSL-interacting proteins in plants. We propose the AHL-Interacting Protein 1 (ALI1) (previously known as AtGalk2) as interacting protein for oxo-C14-HSL in Arabidopsis. We present here several levels of confirmation and suggest that ALI1 is required for the perception of oxo-C14-HSL in Arabidopsis. This is the first direct evidence of a plant protein interacting with a bacterial quorum sensing molecule.
2020-12-20 | GSE156726 | GEO
Project description:The common opportunistic human pathogen Pseudomonas aeruginosa employs quorum sensing QS to regulate a large set of genes involved in virulence and host-pathogen interactions. The Las circuit positioned on the top of the QS hierarchy in P. aeruginosa, makes use of N-acyl-L-homoserine lactones (AHL) as signal molecules, like N-3-oxo-dodecanoyl-L-homoserine lactone (3O-C12-HSL). Here, a quantitative proteomic approach was used to study the effect of natural 3O-C12-HSL and four AHL analogues on the expression and excretion of QS-regulated extracellular proteins. Treatment with AHL compounds resulted in significant difference in appearance of the 3O-C12-HSL-responsive reference proteins related to QS communication and virulence, i.e., a distinct activity as QS modulators. In summary, 3O-C12-HSL has a profound effect on extracellular proteome involved in the pathogenicity of P. aeruginosa, and the four AHL analogues have achieved a distinct inhibitory effect on the extracellular proteome.
2023-10-06 | PXD045881 | Pride
Project description:The study is about the role of Bacteroides thetaiotaomicron in the human gut microbiota, specifically its ability to form biofilms in response to bile salts. The study found that bile induces the expression of certain efflux pumps, and inhibiting these pumps impairs biofilm formation. Among the induced pumps, the BipABC pump is crucial for biofilm formation as it is involved in the efflux of magnesium, which affects the biofilm's extracellular matrix and structure. This discovery sheds light on how intestinal chemical cues, like bile salts, regulate biofilm formation in B. thetaiotaomicron, a significant gut symbiont.
2024-03-19 | E-MTAB-13460 | biostudies-arrayexpress
Project description:We used DNA microarrays to define the physiological roles of the Tap efflux pump in M. bovis BCG during the exponential and the stationary phase of in vitro growth. For this purpose we constructed a M. bovis BCG strain in which the tap gene was inactivated by the insertion of a hygromycin resistance cassette (Ω-hyg). When the gene expression patterns of the tap mutant were compared to the wild-type strain, almost no differences were observed during exponential growth; only seven genes slightly increased their expression. In contrast, more that 100 genes showed a variation in their level of expression during stationary growth. More than ten representative genes were chosen from the microarray experiments and their expression was measured by quantitative RT-PCR using sigA as invariant internal control. In support to the gene expression profiling data, the mRNA levels of all selected genes was significantly different in the tap mutant strain relative to control. A functional category analysis (http://tuberculist.epfl.ch/index.html) of the genes differentially expressed revealed a high proportion belonging to the Virulence, Detoxification, Adaptation (VDA), Intermediary Metabolism and Respiration (IMR), Conserved Hypotheticals (CH), and Cell Wall and Cell Processing (CWCP) categories suggesting a major adaptation to a stress generated by inactivation of the tap efflux pump gene.
2011-12-30 | GSE32249 | GEO