scispace - formally typeset
Search or ask a question
Journal ArticleDOI

AI‐2‐mediated signalling in bacteria

TL;DR: A comprehensive review of the discovery and early characterization of AI-2, current developments in signal detection, transduction and regulation, and the major studies investigating the phenotypes regulated by this molecule is presented.
Abstract: Success in nature depends upon an ability to perceive and adapt to the surrounding environment. Bacteria are not an exception; they recognize and constantly adjust to changing situations by sensing environmental and self-produced signals, altering gene expression accordingly. Autoinducer-2 (AI-2) is a signal molecule produced by LuxS, an enzyme found in many bacterial species and thus proposed to enable interspecies communication. Two classes of AI-2 receptors and many layers and interactions involved in downstream signalling have been identified so far. Although AI-2 has been implicated in the regulation of numerous niche-specific behaviours across the bacterial kingdom, interpretation of these results is complicated by the dual role of LuxS in signalling and the activated methyl cycle, a crucial central metabolic pathway. In this article, we present a comprehensive review of the discovery and early characterization of AI-2, current developments in signal detection, transduction and regulation, and the major studies investigating the phenotypes regulated by this molecule. The development of novel tools should help to resolve many of the remaining questions in the field; we highlight how these advances might be exploited in AI-2 quorum quenching, treatment of diseases, and the manipulation of beneficial behaviours caused by polyspecies communities.
Citations
More filters
Journal ArticleDOI
TL;DR: This Review examines how features of quorum sensing signal–response systems combine to control collective behaviours in Gram-negative bacteria and the implications for host–microbial associations and antibacterial therapy.
Abstract: Bacteria use quorum sensing to orchestrate gene expression programmes that underlie collective behaviours. Quorum sensing relies on the production, release, detection and group-level response to extracellular signalling molecules, which are called autoinducers. Recent work has discovered new autoinducers in Gram-negative bacteria, shown how these molecules are recognized by cognate receptors, revealed new regulatory components that are embedded in canonical signalling circuits and identified novel regulatory network designs. In this Review we examine how, together, these features of quorum sensing signal-response systems combine to control collective behaviours in Gram-negative bacteria and we discuss the implications for host-microbial associations and antibacterial therapy.

1,401 citations

Journal ArticleDOI
TL;DR: Quorum sensing, a cell density-based intercellular communication system, which plays a key role in regulation of the bacterial virulence and biofilm formation, could be a promising target for developing new strategies against P. aeruginosa infection.
Abstract: Pseudomonas aeruginosa causes severe and persistent infections in immune compromised individuals and cystic fibrosis sufferers. The infection is hard to eradicate as P. aeruginosa has developed strong resistance to most conventional antibiotics. The problem is further compounded by the ability of the pathogen to form biofilm matrix, which provides bacterial cells a protected environment withstanding various stresses including antibiotics. Quorum sensing (QS), a cell density-based intercellular communication system, which plays a key role in regulation of the bacterial virulence and biofilm formation, could be a promising target for developing new strategies against P. aeruginosa infection. The QS network of P. aeruginosa is organized in a multi-layered hierarchy consisting of at least four interconnected signaling mechanisms. Evidence is accumulating that the QS regulatory network not only responds to bacterial population changes but also could react to environmental stress cues. This plasticity should be taken into consideration during exploration and development of anti-QS therapeutics.

847 citations


Cites background from "AI‐2‐mediated signalling in bacteri..."

  • ...This article is published with open access at Springerlink.com and journal.hep.com.cn P ro te in gene expression and biofilm formation (Deng et al., 2011; Ng and Bassler, 2009; Pereira et al., 2013; Whitehead et al., 2001)....

    [...]

  • ...gene expression and biofilm formation (Deng et al., 2011; Ng and Bassler, 2009; Pereira et al., 2013; Whitehead et al., 2001)....

    [...]

Journal ArticleDOI
TL;DR: Recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed and questions are posed for targeted investigation of surface-specific community-level microbial features to advance understanding ofsurface-associated microbial community ecology and the biogeochemical functions of these communities.
Abstract: SUMMARY Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific community-level microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration.

696 citations

Journal ArticleDOI
TL;DR: The mechanisms, targets and molecular actors associated with QS interference are presented, with a special emphasis on the description of natural QQ enzymes and chemicals acting as QS inhibition in microbe- microbe and host-microbe interactions.
Abstract: Quorum sensing (QS) refers to the capacity of bacteria to monitor their population density and regulate gene expression accordingly: the QS-regulated processes deal with multicellular behaviors (e.g. growth and development of biofilm), horizontal gene transfer and host-microbe (symbiosis and pathogenesis) and microbe-microbe interactions. QS signaling requires the synthesis, exchange and perception of bacterial compounds, called autoinducers or QS signals (e.g. N-acylhomoserine lactones). The disruption of QS signaling, also termed quorum quenching (QQ), encompasses very diverse phenomena and mechanisms which are presented and discussed in this review. First, we surveyed the QS-signal diversity and QS-associated responses for a better understanding of the targets of the QQ phenomena that organisms have naturally evolved and are currently actively investigated in applied perspectives. Next the mechanisms, targets and molecular actors associated with QS interference are presented, with a special emphasis on the description of natural QQ enzymes and chemicals acting as QS inhibitors. Selected QQ paradigms are detailed to exemplify the mechanisms and biological roles of QS inhibition in microbe-microbe and host-microbe interactions. Finally, some QQ strategies are presented as promising tools in different fields such as medicine, aquaculture, crop production and anti-biofouling area.

450 citations

Journal ArticleDOI
TL;DR: The state of the art for LAB stress behavior is presented, and the stress defense mechanisms that have been reported to date are concentrated on, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope.
Abstract: Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.

398 citations

References
More filters
Book
01 Jan 1996
TL;DR: The Enteric Bacterial Cell and the Age of Bacteria Variations on a Theme by Escherichia is described.
Abstract: Preface The Enteric Bacterial Cell and the Age of Bacteria Variations on a Theme by Escherichia Part I: Molecular Architecture and Assembly of Cell Parts (11 chapters) Part II: Metabolism and General Physiology (58 chapters) Part III: Utilization of Energy for Cell Activities (7 chapters) Part IV: Regulation of Gene Expression (19 chapters) Part V: Growth of Cells and Cultures (12 chapters) Part VI: Genome, Genetics and Evolution (40 chapters) Part VII: Molecular Pathogenesis (7 chapters)

5,749 citations

Journal ArticleDOI
TL;DR: How the marine luminescent bacterium V. fischeri uses the LuxR and LuxI proteins for intercellular communication is reviewed and a newly discovered family of LuxRand LuxI homologs in diverse bacterial species is described.
Abstract: It has long been appreciated that certain groups of bacteria exhibit cooperative behavioral patterns. For example, feeding and sporulation of both myxobacteria and actinomycetes seem optimized for large populations of cells behaving almost as a single multicellular organism. The swarming motility of microorganisms such as Vibrio parahaemolyticus and Proteus mirabilis provides another excellent example of multicellular behavior among bacteria (2). Intercellular communication likewise has been appreciated for several years in Vibrio fischeri, Myxococcus xanthus, Bacillus subtilis, Streptomyces spp., the eukaryotic slime mold Dictyostelium discoideum, and other species (44). Here we first review how the marine luminescent bacterium V. fischeri uses the LuxR and LuxI proteins for intercellular communication and then describe a newly discovered family of LuxR and LuxI homologs in diverse bacterial species.

2,693 citations

Journal ArticleDOI
TL;DR: The IIAGlc protein, part of the glucose-specific PTS, is a central regulatory protein which in its nonphosphorylated form can bind to and inhibit several non-PTS uptake systems and thus prevent entry of inducers.

1,744 citations


Additional excerpts

  • ...phosphorylation (Postma et al., 1993)....

    [...]

Journal ArticleDOI
31 Jan 2002-Nature
TL;DR: It is suggested that addition of naturally occurring borate to anAI-2 precursor generates active AI-2, and a potential biological role for boron is indicated, an element required by a number of organisms but for unknown reasons.
Abstract: Cell-cell communication in bacteria is accomplished through the exchange of extracellular signalling molecules called autoinducers. This process, termed quorum sensing, allows bacterial populations to coordinate gene expression. Community cooperation probably enhances the effectiveness of processes such as bioluminescence, virulence factor expression, antibiotic production and biofilm development. Unlike other autoinducers, which are specific to a particular species of bacteria, a recently discovered autoinducer (AI-2) is produced by a large number of bacterial species. AI-2 has been proposed to serve as a 'universal' signal for inter-species communication. The chemical identity of AI-2 has, however, proved elusive. Here we present the crystal structure of an AI-2 sensor protein, LuxP, in a complex with autoinducer. The bound ligand is a furanosyl borate diester that bears no resemblance to previously characterized autoinducers. Our findings suggest that addition of naturally occurring borate to an AI-2 precursor generates active AI-2. Furthermore, they indicate a potential biological role for boron, an element required by a number of organisms but for unknown reasons.

1,451 citations


"AI‐2‐mediated signalling in bacteri..." refers background in this paper

  • ...2) (Chen et al., 2002)....

    [...]

  • ...Typhimurium (Chen et al., 2002; Miller et al., 2004)....

    [...]

  • ...Crystallization of the LuxP-ligand complex yielded the first structure of a molecule with AI-2 activity, a cyclic, borated form of AI-2 called S-2-methyl-2,3,3,4-tetrahydroxytetrahydrofuranborate (S-THMF-borate) (Chen et al., 2002)....

    [...]

  • ...2b) (Chen et al., 2002; Miller et al., 2004)....

    [...]

  • ...To date, two classes of AI-2-specific receptors have been well characterized (Chen et al., 2002; Miller et al., 2004)....

    [...]

Journal ArticleDOI
TL;DR: It is argued that the Vibrio quorum-sensing systems are optimally designed to precisely translate extracellular autoinducer information into internal changes in gene expression.
Abstract: Quorum sensing is a cell-cell communication process in which bacteria use the production and detection of extracellular chemicals called autoinducers to monitor cell population density. Quorum sensing allows bacteria to synchronize the gene expression of the group, and thus act in unison. Here, we review the mechanisms involved in quorum sensing with a focus on the Vibrio harveyi and Vibrio cholerae quorum-sensing systems. We discuss the differences between these two quorum-sensing systems and the differences between them and other paradigmatic bacterial signal transduction systems. We argue that the Vibrio quorum-sensing systems are optimally designed to precisely translate extracellular autoinducer information into internal changes in gene expression. We describe how studies of the V. harveyi and V. cholerae quorum-sensing systems have revealed some of the fundamental mechanisms underpinning the evolution of collective behaviors.

1,448 citations