Quorum‐sensing autoinducer molecules produced by members of a multispecies biofilm promote horizontal gene transfer to Vibrio cholerae
TL;DR: It is demonstrated that comEA transcription and the horizontal acquisition of DNA by V. cholerae are induced in response to purified CAI-1 and AI-2, and also by autoinducers derived from other Vibrios co-cultured with V. Cholerae within a mixed-species biofilm, suggesting that autoinducer communication within a consortium may promote DNA exchange among VibRIos.
Abstract: Vibrio cholerae, the causative agent of cholera and a natural inhabitant of aquatic environments, regulates numerous behaviors using a quorum-sensing (QS) system conserved among many members of the marine genus Vibrio. The Vibrio QS response is mediated by two extracellular autoinducer (AI) molecules: CAI-I, which is produced only by Vibrios, and AI-2, which is produced by many bacteria. In marine biofilms on chitinous surfaces, QS-proficient V. cholerae become naturally competent to take up extracellular DNA. Because the direct role of AIs in this environmental behavior had not been determined, we sought to define the contribution of CAI-1 and AI-2 in controlling transcription of the competence gene, comEA, and in DNA uptake. In this study we demonstrated that comEA transcription and the horizontal acquisition of DNA by V. cholerae are induced in response to purified CAI-1 and AI-2, and also by autoinducers derived from other Vibrios co-cultured with V. cholerae within a mixed-species biofilm. These results suggest that autoinducer communication within a consortium may promote DNA exchange among Vibrios, perhaps contributing to the evolution of these bacterial pathogens.
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TL;DR: Production of AHLs in both bacterial strains were found to be density-dependent, and the AHLs activity reached a maximum level in their middle logarithmic phase and decreased in the stationary phase, while the addition of exogenous AHLs and QS inhibitor decreased the specific protease activity both of the Serratia A2 and Aeromonas B1.
Abstract: Quorum sensing (QS) is a cell-to-cell communication mechanism through which microbial cells communicate and regulate their wide variety of biological activities. N-acyl homoserine lactones (AHLs) are considered to be the most important QS signaling molecules produced by several Gram-negative bacteria. The present study aimed to screen the AHLs-producing bacteria from spoiled vacuum-packaged refrigerated turbot (Scophthalmus maximus) by biosensor assays, and the profiles of AHLs produced by these bacteria were determined using reversed-phase thin-layer chromatography (RP-TLC) and gas chromatography-mass spectrometry (GC-MS). Effects of exogenous AHLs and QS inhibitor (QSI) on the phenotypes (i.e., extracellular proteolytic activity and biofilm formation) of the AHLs-producing bacteria were also evaluated. Our results demonstrated that eight out of twenty-two isolates were found to produce AHLs. Three of the AHLs-producing isolates were identified as Serratia sp., and the other five were found to belong to the family of Aeromonas. Two isolates (i.e., S. liquefaciens A2 and A. sobria B1) with higher AHLs-producing activities were selected for further studies. Mainly, RP-TLC and GC-MS analysis revealed three AHLs, i.e., 3-oxo-C6-HSL, C8-HSL and C10-HSL were produced by S. liquefaciens A2, while five AHLs, i.e., C4-HSL, C6-HSL, C8-HSL, C10-HSL, and C12-HSL, were produced by A. sobria B1. Moreover, production of AHLs in both bacterial strains were found to be density-dependent, and the AHLs activity reached a maximum level in their middle logarithmic phase and decreased in the stationary phase. The addition of exogenous AHLs and QSI decreased the specific protease activity both of the Serratia A2 and Aeromonas B1. Exogenous AHLs inhibited the biofilm formation of Serratia A2 while it enhanced the biofilm formation in Aeromonas B1. QSI inhibited the specific protease activity and biofilm formation in both bacterial strains.
16 citations
Cites background from "Quorum‐sensing autoinducer molecule..."
...…(Liu et al., 2007); the application of furanones (QS inhibitor) prolonged the shelf-life of fermented milk by reducing the motility and exoenzyme activity of Pseudomonas fluorescens (Shobharani and Agrawal, 2010); and QS regulated biofilm formation in Vibrio cholerae (Antonova and Hammer, 2011)....
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..., 2007); the application of furanones (QS inhibitor) prolonged the shelf-life of fermented milk by reducing the motility and exoenzyme activity of Pseudomonas fluorescens (Shobharani and Agrawal, 2010); and QS regulated biofilm formation in Vibrio cholerae (Antonova and Hammer, 2011)....
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TL;DR: This study compares prominent seventh pandemic V. cholerae isolates for their natural transformability and decipher underlying defects that mask the high degree of competence conservation, identifying several strain‐specific defects, mostly in genes that encode key players in quorum sensing.
Abstract: The human pathogen Vibrio cholerae serves as a model organism for many important processes ranging from pathogenesis to natural transformation, which has been extensively studied in this bacterium. Previous work has deciphered important regulatory circuits involved in natural competence induction as well as mechanistic details related to its DNA acquisition and uptake potential. However, since competence was first reported for V. cholerae in 2005, many researchers have struggled with reproducibility in certain strains. In this study, we therefore compare prominent seventh pandemic V. cholerae isolates, namely strains A1552, N16961, C6706, C6709, E7946, P27459, and the close relative MO10, for their natural transformability and decipher underlying defects that mask the high degree of competence conservation. Through a combination of experimental approaches and comparative genomics based on new whole-genome sequences and de novo assemblies, we identify several strain-specific defects, mostly in genes that encode key players in quorum sensing. Moreover, we provide evidence that most of these deficiencies might have recently occurred through laboratory domestication events or through the acquisition of mobile genetic elements. Lastly, we highlight that differing experimental approaches between research groups might explain more of the variations than strain-specific alterations.
15 citations
Cites background or methods from "Quorum‐sensing autoinducer molecule..."
...C6706ΔluxSΔcqsA C6706strΔluxSΔcqsA; StrR MB#4244 (Antonova and Hammer, 2011); Hammer laboratory strain BH1575...
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...…C6706strΔluxSΔcqsA; StrR MB#4244 (Antonova and Hammer, 2011); Hammer laboratory strain BH1575 - 3 - C6706ΔhapR C6706str ΔhapR; StrR MB#4252 (Antonova and Hammer, 2011); Hammer laboratory strain BH1543 ΔvqmA A1552 with vqmA deleted using TransFlp method (A1552ΔvqmA::FRT);…...
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...(Meibom et al., 2005) C6706 (C6706str) C6706str; El Tor biotype, O1; Str R MB#4242 (Antonova and Hammer, 2011); Hammer laboratory strain C6706str C6706ΔcqsA C6706strΔcqsA; StrR MB#4246 (Antonova and Hammer, 2011); Hammer laboratory strain BH1523 C6706ΔluxS C6706strΔluxS; StrR MB#4248 (Antonova and…...
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...C6706 (C6706str) C6706str; El Tor biotype, O1; Str R MB#4242 (Antonova and Hammer, 2011); Hammer laboratory strain C6706str...
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...…C6706strΔluxS; StrR MB#4248 (Antonova and Hammer, 2011); Hammer laboratory strain BH1515 C6706ΔluxSΔcqsA C6706strΔluxSΔcqsA; StrR MB#4244 (Antonova and Hammer, 2011); Hammer laboratory strain BH1575 - 3 - C6706ΔhapR C6706str ΔhapR; StrR MB#4252 (Antonova and Hammer, 2011); Hammer…...
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TL;DR: The structure–function analyses presented here improve the understanding of the complex mechanisms in the transcriptional regulation of VqmA in Vibrio spp.
15 citations
TL;DR: The role of Chitin and its hydrolysis products generated by Vibrio cholerae chitinases in mechanisms of its adaptation in water environments, metabolism, preservation, acquisition of pathogenic potential, and its epidemiological value are reviewed.
Abstract: The role of chitin and its hydrolysis products generated by Vibrio cholerae chitinases in mechanisms of its adaptation in water environments, metabolism, preservation, acquisition of pathogenic potential, and its epidemiological value are reviewed. Chitin utilization by V. cholerae as a source of energy, carbon, and nitrogen is described. Chitin association promotes biofilm formation on natural chitinous surfaces, increasing V. cholerae resistance to adverse factors in ecological niches: the human body and water environments with its inhabitants. Hydrolytic enzymes regulated by the corresponding genes result in complete chitin biodegradation by a chitinolytic catabolic cascade. Consequences of V. cholerae cell and chitin interaction at different hierarchical levels include metabolic and physiological cell reactions such as chemotaxis, cell division, biofilm formation, induction of genetic competence, and commensalic and symbiotic mutual relations with higher organisms, nutrient cycle, pathogenicity for humans, and water organisms that is an example of successful interrelation of bacteria and substratum in the ecology of the microorganism.
15 citations
Cites background from "Quorum‐sensing autoinducer molecule..."
...cholerae competence and trans formation processes [43, 45, 52, 53, 57, 58]....
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...These events are critical for emergence of natural competence [40, 52, 53]....
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TL;DR: In this paper , the authors show that S. aureus-derived heme, likely in the form of released hemoproteins, promotes E. faecalis biofilm formation.
Abstract: The contribution of biofilms to virulence and as a barrier to treatment is well-established for Staphylococcus aureus and Enterococcus faecalis, both nosocomial pathogens frequently isolated from biofilm-associated infections. Despite frequent co-isolation, their interactions in biofilms have not been well-characterized. We report that in combination, these two species can give rise to augmented biofilms biomass that is dependent on the activation of E. faecalis aerobic respiration. In E. faecalis, respiration requires both exogenous heme to activate the cydAB-encoded heme-dependent cytochrome bd, and the availability of O2. We determined that the ABC transporter encoded by cydDC contributes to heme import. In dual species biofilms, S. aureus provides the heme to activate E. faecalis respiration. S. aureus mutants deficient in heme biosynthesis were unable to augment biofilms whereas heme alone is sufficient to augment E. faecalis mono-species biofilms. Our results demonstrate that S. aureus-derived heme, likely in the form of released hemoproteins, promotes E. faecalis biofilm formation, and that E. faecalis gelatinase activity facilitates heme extraction from hemoproteins. This interspecies interaction and metabolic cross-feeding may explain the frequent co-occurrence of these microbes in biofilm-associated infections.
14 citations
References
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Book•
15 Jan 2001
TL;DR: Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years as mentioned in this paper and has been so popular, or so influential, that no other manual has been more widely used and influential.
Abstract: Molecular Cloning has served as the foundation of technical expertise in labs worldwide for 30 years. No other manual has been so popular, or so influential. Molecular Cloning, Fourth Edition, by the celebrated founding author Joe Sambrook and new co-author, the distinguished HHMI investigator Michael Green, preserves the highly praised detail and clarity of previous editions and includes specific chapters and protocols commissioned for the book from expert practitioners at Yale, U Mass, Rockefeller University, Texas Tech, Cold Spring Harbor Laboratory, Washington University, and other leading institutions. The theoretical and historical underpinnings of techniques are prominent features of the presentation throughout, information that does much to help trouble-shoot experimental problems. For the fourth edition of this classic work, the content has been entirely recast to include nucleic-acid based methods selected as the most widely used and valuable in molecular and cellular biology laboratories. Core chapters from the third edition have been revised to feature current strategies and approaches to the preparation and cloning of nucleic acids, gene transfer, and expression analysis. They are augmented by 12 new chapters which show how DNA, RNA, and proteins should be prepared, evaluated, and manipulated, and how data generation and analysis can be handled. The new content includes methods for studying interactions between cellular components, such as microarrays, next-generation sequencing technologies, RNA interference, and epigenetic analysis using DNA methylation techniques and chromatin immunoprecipitation. To make sense of the wealth of data produced by these techniques, a bioinformatics chapter describes the use of analytical tools for comparing sequences of genes and proteins and identifying common expression patterns among sets of genes. Building on thirty years of trust, reliability, and authority, the fourth edition of Mol
215,169 citations
TL;DR: It is evident that biofilm formation is an ancient and integral component of the prokaryotic life cycle, and is a key factor for survival in diverse environments.
Abstract: Biofilms--matrix-enclosed microbial accretions that adhere to biological or non-biological surfaces--represent a significant and incompletely understood mode of growth for bacteria. Biofilm formation appears early in the fossil record (approximately 3.25 billion years ago) and is common throughout a diverse range of organisms in both the Archaea and Bacteria lineages, including the 'living fossils' in the most deeply dividing branches of the phylogenetic tree. It is evident that biofilm formation is an ancient and integral component of the prokaryotic life cycle, and is a key factor for survival in diverse environments. Recent advances show that biofilms are structurally complex, dynamic systems with attributes of both primordial multicellular organisms and multifaceted ecosystems. Biofilm formation represents a protected mode of growth that allows cells to survive in hostile environments and also disperse to colonize new niches. The implications of these survival and propagative mechanisms in the context of both the natural environment and infectious diseases are discussed in this review.
6,170 citations
"Quorum‐sensing autoinducer molecule..." refers background in this paper
...We reasoned that a mixed-species consortium may more closely reflect conditions in environmental biofilms that are unlikely to be mono-species in composition (Hall-Stoodley et al., 2004; Wintermute & Silver, 2010)....
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TL;DR: The evolution of quorum sensing systems in bacteria could, therefore, have been one of the early steps in the development of multicellularity.
Abstract: ▪ Abstract Quorum sensing is the regulation of gene expression in response to fluctuations in cell-population density. Quorum sensing bacteria produce and release chemical signal molecules called autoinducers that increase in concentration as a function of cell density. The detection of a minimal threshold stimulatory concentration of an autoinducer leads to an alteration in gene expression. Gram-positive and Gram-negative bacteria use quorum sensing communication circuits to regulate a diverse array of physiological activities. These processes include symbiosis, virulence, competence, conjugation, antibiotic production, motility, sporulation, and biofilm formation. In general, Gram-negative bacteria use acylated homoserine lactones as autoinducers, and Gram-positive bacteria use processed oligo-peptides to communicate. Recent advances in the field indicate that cell-cell communication via autoinducers occurs both within and between bacterial species. Furthermore, there is mounting data suggesting that ba...
4,449 citations
"Quorum‐sensing autoinducer molecule..." refers background in this paper
...…molecules has been studied in many laboratory systems that relied exclusively on cell-free culture fluids or monocultures (Bassler et al., 1997; Miller & Bassler, 2001; Henke & Bassler, 2004a), single-species co-cultures (Hammer & Bassler, 2007), or cocultures of Vibrios with other bacteria…...
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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
"Quorum‐sensing autoinducer molecule..." refers background in this paper
...…bacterium and the causative agent of the disease cholera, produces and then responds to extracellular small molecules called autoinducers (AIs) to collectively control gene expression and coordinate group behaviors, a process called quorum sensing (QS) (Fuqua et al., 1994; Ng & Bassler, 2009)....
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TL;DR: The emergence of toxigenic V. cholerae involves horizontal gene transfer that may depend on in vivo gene expression, and is shown here to be encoded by a filamentous bacteriophage (designated CTXΦ), which is related to coliphage M13.
Abstract: Vibrio cholerae, the causative agent of cholera, requires two coordinately regulated factors for full virulence: cholera toxin (CT), a potent enterotoxin, and toxin-coregulated pili (TCP), surface organelles required for intestinal colonization. The structural genes for CT are shown here to be encoded by a filamentous bacteriophage (designated CTXphi), which is related to coliphage M13. The CTXphi genome chromosomally integrated or replicated as a plasmid. CTXphi used TCP as its receptor and infected V. cholerae cells within the gastrointestinal tracts of mice more efficiently than under laboratory conditions. Thus, the emergence of toxigenic V. cholerae involves horizontal gene transfer that may depend on in vivo gene expression.
1,744 citations
"Quorum‐sensing autoinducer molecule..." refers background in this paper
...Transduction of the cholera toxin genes encoded within a filamentous phage (CTXF) permits exchange of virulence factors among V. cholerae (Waldor & Mekalanos, 1996)....
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