The N-Terminal Domain of
            <i>Aliivibrio fischeri</i>
            LuxR Is a Target of the GroEL Chaperonin

Манухов, И. В.; Melkina, O. E.; Goryanin, Ignatiy I.; Baranova, Ancha; Zavilgelsky, G. B.

doi:10.1128/jb.00754-10

Cited by 12 publications

(6 citation statements)

References 24 publications

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“…2,4-DAPG was added to P. carotovorum populations in the beginning of log-phase and growth monitoring continued by a spectrophotometer. Three hours later, the amount of AI produced in culture media of pectobacteria was analyzed by recombinant E. coli MG 1655 pVFR1-lux, which contains the plasmid pVFR1 carrying a 1-kb DNA fragment of A. fischeri including luxR and P l /P r promoters along with a luxCDABE cassette of Photorhabdus luminescens [ 19 ]. LuxR is a quorum-sensitive transcriptional regulator of the luxICDABEG operon.…”

Section: Resultsmentioning

confidence: 99%

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Bacterial-Derived Plant Protection Metabolite 2,4-Diacetylphloroglucinol: Effects on Bacterial Cells at Inhibitory and Subinhibitory Concentrations

et al. 2020

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2,4-Diacetylphloroglucinol (2,4-DAPG) is a well-known bacterial secondary metabolite, however, its mechanism of inhibitory and subinhibitory action on bacterial cells is still poorly understood. The mechanism of 2,4-DAPG action on model bacterial strains was investigated using fluorescent spectroscopy and the action of the antibiotic was found to involve a rapid increase in membrane permeability that was accompanied by a reduction in its viability in nutrient-poor medium. At the same time, antibacterial action in nutrient-rich medium developed for several hours. Atomic force microscopy demonstrated time-dependent disturbances in the outer membrane of Escherichia coli when exposed to 2,4-DAPG, while Staphylococcusaureus cells have been visualized with signs of intracellular leakage. In addition, 2,4-DAPG inhibited the metabolic activity of S. aureus and E. coli bacterial cells in mature biofilms. Observed differences in the antibiofilm activity were dependent upon antibiotic concentration. The intracellular targets of the action of 2,4-DAPG were assessed using bacterial biosensors with inducible bioluminescence corresponding to DNA and protein damage. It was unable to register any positive response from either sensor. As a result, the bactericidal action of 2,4-DAPG is believed to be associated with the destruction of the bacterial barrier structures. The subinhibitory effect of 2,4-diacetylphloroglucinol was tested on quorum-sensing mediated processes in Pectobacterium carotovorum. Subinhibitory concentrations of 2,4-DAPG were found to lower the biosynthesis of acyl-homoserine lactones in P. carotovorum in a dose-dependent manner. Further investigation elucidated that 2,4-DAPG inhibits the metabolic activity of bacteria without affecting their viability.

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Section: Resultsmentioning

confidence: 99%

“…E. coli MG 1655 pVFR1-lux is a bioluminescence-based QS-biosensor [ 19 , 20 ]. This strain carries the plasmid pVFR1, which possesses the luxRI’: luxCDABE (I ’meaning luxI mutated) bioluminescent reporter gene.…”

Section: Methodsmentioning

confidence: 99%

Bacterial-Derived Plant Protection Metabolite 2,4-Diacetylphloroglucinol: Effects on Bacterial Cells at Inhibitory and Subinhibitory Concentrations

et al. 2020

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“…The increase in the background luminosity ( Figure 2 and Figure 3 ) could be explained by a partial degradation of LuxR proteins by proteases with a subsequent AI-independent activation of transcription by their C-terminal fragments. The AI-independent activation of luxCDABE and luxI promoters by the C-terminal domain of LuxR was shown in [ 28 , 32 , 33 ]. The luxR1 protein is not subject to degradation by the Lon protease and does not require GroEL/ES for assembly [ 22 ].…”

Section: Discussionmentioning

confidence: 99%

Influence of the luxR Regulatory Gene Dosage and Expression Level on the Sensitivity of the Whole-Cell Biosensor to Acyl-Homoserine Lactone

et al. 2021

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Aliivibrio fischeri LuxR and Aliivibrio logei LuxR1 and LuxR2 regulatory proteins are quorum sensing transcriptional (QS) activators, inducing promoters of luxICDABEG genes in the presence of an autoinducer (3-oxo-hexanoyl-l-homoserine lactone). In the Aliivibrio cells, luxR genes are regulated by HNS, CRP, LitR, etc. Here we investigated the role of the luxR expression level in LuxI/R QS system functionality and improved the whole-cell biosensor for autoinducer detection. Escherichia coli-based bacterial lux-biosensors were used, in which Photorhabdus luminescensluxCDABE genes were controlled by LuxR-dependent promoters and luxR, luxR1, or luxR2 regulatory genes. We varied either the dosage of the regulatory gene in the cells using additional plasmids, or the level of the regulatory gene expression using the lactose operon promoter. It was shown that an increase in expression level, as well as dosage of the regulatory gene in biosensor cells, leads to an increase in sensitivity (the threshold concentration of AI is reduced by one order of magnitude) and to a two to threefold reduction in response time. The best parameters were obtained for a biosensor with an increased dosage of luxRA. fischeri (sensitivity to 3-oxo-hexanoyl-l-homoserine lactone reached 30–100 pM).

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“…The expression of LuxR family transcriptional regulator was up-regulated by diazinon exposure (Figure 2A). The folding of LuxR polypeptide requires GroEL chaperonin (Manukhov et al, 2010), which was also upregulated by diazinon exposure (Figure 2A). In Gram-positive bacteria, accessory gene regulator (Agr) is a conventional quorum sensing system with a four-gene operon carrying agrA, agrB, agrC, and agrD, which influences the expression of many virulence genes (Darkoh et al, 2015).…”

Section: Diazinon Exposure Altered the Expression Profile Of Gut Metatranscriptomementioning

confidence: 97%

Editor’s Highlight: Organophosphate Diazinon Altered Quorum Sensing, Cell Motility, Stress Response, and Carbohydrate Metabolism of Gut Microbiome

Gao

Bian

Chi

et al. 2017

Toxicological Sciences

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The gut microbiome plays a key role in energy production, immune system development, and host resistance against invading pathogens, etc. Disruption of gut bacterial homeostasis is associated with a number of human diseases. Several environmental chemicals have been reported to induce alterations of the gut microbiome. Diazinon, one of important organophosphate insecticides, has been widely used in agriculture. Diazinon and its metabolites are readily detected in different environmental settings and human urine. The toxicity of organophosphates has been a long-standing public health concern. We recently demonstrated that organophosphate insecticide diazinon perturbed the gut microbiome composition of mice. However, the functional impact of exposure on the gut microbiome has not been adequately assessed yet. In particular, the molecular mechanism responsible for exposure-induced microbial profile and community structure changes has not been identified. Therefore, in this study, we used metatranscriptomics to examine the effects of diazinon exposure on the gut metatranscriptome in C57BL/6 mice. Herein, we demonstrated for the first time that organophosphate diazinon modulated quorum sensing, which may serve as a key mechanism to regulate bacterial population, composition, and more importantly, their functional genes. In addition, we also found that diazinon exposure activated diverse stress response pathways and profoundly impaired energy metabolism of gut bacteria. These findings provide new understandings of the functional interplay between the gut microbiome and environmental chemicals, such as organophosphates.

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The N-Terminal Domain of Aliivibrio fischeri LuxR Is a Target of the GroEL Chaperonin

Cited by 12 publications

References 24 publications

Bacterial-Derived Plant Protection Metabolite 2,4-Diacetylphloroglucinol: Effects on Bacterial Cells at Inhibitory and Subinhibitory Concentrations

Bacterial-Derived Plant Protection Metabolite 2,4-Diacetylphloroglucinol: Effects on Bacterial Cells at Inhibitory and Subinhibitory Concentrations

Influence of the luxR Regulatory Gene Dosage and Expression Level on the Sensitivity of the Whole-Cell Biosensor to Acyl-Homoserine Lactone

Editor’s Highlight: Organophosphate Diazinon Altered Quorum Sensing, Cell Motility, Stress Response, and Carbohydrate Metabolism of Gut Microbiome

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