scholarly journals Messing with Bacterial Quorum Sensing

2006 ◽  
Vol 70 (4) ◽  
pp. 859-875 ◽  
Author(s):  
Juan E. González ◽  
Neela D. Keshavan
Keyword(s):  
Quorum Sensing ◽  
Pathogenic Bacteria ◽  
Toxin Production ◽  
Negative Influence ◽  
Fine Tuning ◽  
Signal Molecules ◽  
Bacterial Signaling ◽  
Bacterial Quorum Sensing ◽  
Successful Establishment ◽  
Bacterial Quorum

SUMMARY Quorum sensing is widely recognized as an efficient mechanism to regulate expression of specific genes responsible for communal behavior in bacteria. Several bacterial phenotypes essential for the successful establishment of symbiotic, pathogenic, or commensal relationships with eukaryotic hosts, including motility, exopolysaccharide production, biofilm formation, and toxin production, are often regulated by quorum sensing. Interestingly, eukaryotes produce quorum-sensing-interfering (QSI) compounds that have a positive or negative influence on the bacterial signaling network. This eukaryotic interference could result in further fine-tuning of bacterial quorum sensing. Furthermore, recent work involving the synthesis of structural homologs to the various quorum-sensing signal molecules has resulted in the development of additional QSI compounds that could be used to control pathogenic bacteria. The creation of transgenic plants that express bacterial quorum-sensing genes is yet another strategy to interfere with bacterial behavior. Further investigation on the manipulation of quorum-sensing systems could provide us with powerful tools against harmful bacteria.

scholarly journals Phage-Encoded LuxR-Type Receptors Responsive to Host-Produced Bacterial Quorum-Sensing Autoinducers

2019 ◽  
Author(s):  
Justin E. Silpe ◽  
Bonnie L. Bassler
Keyword(s):  
Quorum Sensing ◽  
Pathogenic Bacteria ◽  
Cell Communication ◽  
Signal Molecules ◽  
Host Bacterium ◽  
Gram Negative ◽  
Collective Behaviors ◽  
Bacterial Quorum Sensing ◽  
Genes Encoding ◽  
Bacterial Quorum

AbstractQuorum sensing (QS) is a process of cell-to-cell communication that bacteria use to orchestrate collective behaviors. QS relies on the cell-density-dependent production, accumulation, and receptor-mediated detection of extracellular signaling molecules called autoinducers (AIs). Gram-negative bacteria commonly use N-acyl homoserine lactones (AHLs) as their AIs and they are detected by LuxR-type receptors. Often, LuxR-type receptors are insoluble when not bound to a cognate AI. In this report, we show that LuxR-type receptors are encoded on phage genomes and, in the cases we tested, the phage LuxR-type receptors bind to and are solubilized specifically by the AHL AI produced by the host bacterium. We do not yet know the viral activities that are controlled by these phage QS receptors, however, our observations, coupled with recent reports, suggest that their occurrence is more widespread than previously appreciated. Using receptor-mediated detection of QS AIs could enable phages to garner information concerning the population density status of their bacterial hosts. We speculate that such information can be exploited by phages to optimize the timing of execution of particular steps in viral infection.ImportanceBacteria communicate with chemical signal molecules to regulate group behaviors in a process called quorum sensing (QS). In this report, we find that genes encoding receptors for Gram-negative bacterial QS communication molecules are present on genomes of viruses that infect these bacteria. These viruses are called phages. We show that two phage-encoded receptors, like their bacterial counterparts, bind to the communication molecule produced by the host bacterium, suggesting that phages can “listen in” on their bacterial hosts. Interfering with bacterial QS and using phages to kill pathogenic bacteria represent attractive possibilities for development of new antimicrobials to combat pathogens that are resistant to traditional antibiotics. Our findings of interactions between phages and QS bacteria need consideration as new antimicrobial therapies are developed.

Influence of Polyphenols on Bacterial Biofilm Formation and Quorum-sensing

2003 ◽  
Vol 58 (11-12) ◽  
pp. 879-884 ◽  
Author(s):  
Birgit Huber ◽  
Leo Eberl ◽  
Walter Feucht ◽  
Jürgen Polster
Keyword(s):  
Gene Regulation ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Bacterial Biofilm ◽  
Signal Molecules ◽  
Bacterial Cells ◽  
Regulatory Systems ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum

Abstract Many bacteria utilize sophisticated regulatory systems to ensure that some functions are only expressed when a particular population density has been reached. The term ‘quorumsensing’ has been coined to describe this form of density-dependent gene regulation which relies on the production and perception of small signal molecules by bacterial cells. As in many pathogenic bacteria the production of virulence factors is quorum-sensing regulated, it has been suggested that this form of gene regulation allows the bacteria to remain invisible to the defence systems of the host until the population is sufficiently large to successfully establish the infection. Here we present first evidence that polyphenolic compounds can interfere with bacterial quorum-sensing. Since polyphenols are widely distributed in the plant kingdom, they may be important for promoting plant fitness.

scholarly journals Phage-Encoded LuxR-Type Receptors Responsive to Host-Produced Bacterial Quorum-Sensing Autoinducers

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Justin E. Silpe ◽  
Bonnie L. Bassler
Keyword(s):  
Quorum Sensing ◽  
Pathogenic Bacteria ◽  
Cell Communication ◽  
Signal Molecules ◽  
Host Bacterium ◽  
Gram Negative ◽  
Collective Behaviors ◽  
Bacterial Quorum Sensing ◽  
Genes Encoding ◽  
Bacterial Quorum

ABSTRACT Quorum sensing (QS) is a process of cell-to-cell communication that bacteria use to orchestrate collective behaviors. QS relies on the cell-density-dependent production, accumulation, and receptor-mediated detection of extracellular signaling molecules called autoinducers (AIs). Gram-negative bacteria commonly use N-acyl homoserine lactones (AHLs) as their AIs, and they are detected by LuxR-type receptors. Often, LuxR-type receptors are insoluble when not bound to a cognate AI. In this report, we show that LuxR-type receptors are encoded on phage genomes, and in the cases we tested, the phage LuxR-type receptors bind to and are solubilized specifically by the AHL AI produced by the host bacterium. We do not yet know the viral activities that are controlled by these phage QS receptors; however, our observations, coupled with recent reports, suggest that their occurrence is more widespread than previously appreciated. Using receptor-mediated detection of QS AIs could enable phages to garner information concerning the population density status of their bacterial hosts. We speculate that such information can be exploited by phages to optimize the timing of execution of particular steps in viral infection. IMPORTANCE Bacteria communicate with chemical signal molecules to regulate group behaviors in a process called quorum sensing (QS). In this report, we find that genes encoding receptors for Gram-negative bacterial QS communication molecules are present on genomes of viruses that infect these bacteria. These viruses are called phages. We show that two phage-encoded receptors, like their bacterial counterparts, bind to the communication molecule produced by the host bacterium, suggesting that phages can “listen in” on their bacterial hosts. Interfering with bacterial QS and using phages to kill pathogenic bacteria represent attractive possibilities for development of new antimicrobials to combat pathogens that are resistant to traditional antibiotics. Our findings of interactions between phages and QS bacteria need consideration as new antimicrobial therapies are developed.

Bacterial Quorum Sensing During Infection

2020 ◽  
Vol 74 (1) ◽  
pp. 201-219 ◽  
Author(s):  
Sheyda Azimi ◽  
Alexander D. Klementiev ◽  
Marvin Whiteley ◽  
Stephen P. Diggle
Keyword(s):  
Quorum Sensing ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Human Infection ◽  
Future Research ◽  
Virulence Determinants ◽  
Plant Laboratory ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum

Bacteria are highly interactive and possess an extraordinary repertoire of intercellular communication and social behaviors, including quorum sensing (QS). QS has been studied in detail at the molecular level, so mechanistic details are well understood in many species and are often involved in virulence. The use of different animal host models has demonstrated QS-dependent control of virulence determinants and virulence in several human pathogenic bacteria. QS also controls virulence in several plant pathogenic species. Despite the role QS plays in virulence during animal and plant laboratory-engineered infections, QS mutants are frequently isolated from natural infections, demonstrating that the function of QS during infection and its role in pathogenesis remain poorly understood and are fruitful areas for future research. We discuss the role of QS during infection in various organisms and highlight approaches to better understand QS during human infection. This is an important consideration in an era of growing antimicrobial resistance, when we are looking for new ways to target bacterial infections.

Quorum Sensing: A Primer for Food Microbiologists†

2004 ◽  
Vol 67 (5) ◽  
pp. 1053-1070 ◽  
Author(s):  
JAMES L. SMITH ◽  
PINA M. FRATAMICO ◽  
JOHN S. NOVAK
Keyword(s):  
Quorum Sensing ◽  
Cell Communication ◽  
Toxin Production ◽  
Clinical Aspects ◽  
Specific Cell ◽  
Cellular Functions ◽  
Signaling Mechanism ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum ◽  
Cell Densities

Quorum sensing is a signaling mechanism through which bacteria modulate a number of cellular functions (genes), including sporulation, biofilm formation, bacteriocin production, virulence responses, as well as others. Quorum sensing is a mechanism of cell-to-cell communication and is mediated by extracellular chemical signals generated by the bacteria when specific cell densities are reached. When the concentration of the signal (and cell population) is sufficiently high, the target gene or genes are either activated or repressed. Quorum sensing increases the ability of the bacteria to have access to nutrients or to more favorable environmental niches and enhances bacterial defenses against eukaryotic hosts, competing bacteria, and environmental stresses. The physiological and clinical aspects of quorum sensing have received considerable attention and have been studied at the molecular level. Little is known, however, on the role of quorum sensing in food spoilage or in the growth and/or toxin production of pathogens present in food. A number of compounds have been isolated or synthesized that antagonize quorum sensors, and application of these antagonists may potentially be useful in inhibiting the growth or virulence mechanisms of bacteria in different environments, including food. It is important that food microbiologists have an awareness and an understanding of the mechanisms involved in bacterial quorum sensing, since strategies targeting quorum sensing may offer a means to control the growth of undesirable bacteria in foods.

scholarly journals Cover Picture: Fine-Tuning Covalent Inhibition of Bacterial Quorum Sensing (ChemBioChem 9/2016)

ChemBioChem ◽  
2016 ◽  
Vol 17 (9) ◽  
pp. 786-786 ◽  
Author(s):  
Neri Amara ◽  
Rachel Gregor ◽  
Josep Rayo ◽  
Rambabu Dandela ◽  
Erik Daniel ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Fine Tuning ◽  
Covalent Inhibition ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum

scholarly journals l-Canavanine Made by Medicago sativa Interferes with Quorum Sensing in Sinorhizobium meliloti

2005 ◽  
Vol 187 (24) ◽  
pp. 8427-8436 ◽  
Author(s):  
Neela D. Keshavan ◽  
Puneet K. Chowdhary ◽  
Donovan C. Haines ◽  
Juan E. González
Keyword(s):  
Quorum Sensing ◽  
Medicago Sativa ◽  
Sinorhizobium Meliloti ◽  
Signal Molecules ◽  
Bacterial Strains ◽  
Signal Molecule ◽  
Gram Negative ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum ◽  
Regulated Gene Expression

ABSTRACT Sinorhizobium meliloti is a gram-negative soil bacterium, capable of establishing a nitrogen-fixing symbiosis with its legume host, alfalfa (Medicago sativa). Quorum sensing plays a crucial role in this symbiosis, where it influences the nodulation process and the synthesis of the symbiotically important exopolysaccharide II (EPS II). S. meliloti has three quorum-sensing systems (Sin, Tra, and Mel) that use N-acyl homoserine lactones as their quorum-sensing signal molecule. Increasing evidence indicates that certain eukaryotic hosts involved in symbiotic or pathogenic relationships with gram-negative bacteria produce quorum-sensing-interfering (QSI) compounds that can cross-communicate with the bacterial quorum-sensing system. Our studies of alfalfa seed exudates suggested the presence of multiple signal molecules capable of interfering with quorum-sensing-regulated gene expression in different bacterial strains. In this work, we choose one of these QSI molecules (SWI) for further characterization. SWI inhibited violacein production, a phenotype that is regulated by quorum sensing in Chromobacterium violaceum. In addition, this signal molecule also inhibits the expression of the S. meliloti exp genes, responsible for the production of EPS II, a quorum-sensing-regulated phenotype. We identified this molecule as l-canavanine, an arginine analog, produced in large quantities by alfalfa and other legumes.

scholarly journals Cross-kingdom signalling: exploitation of bacterial quorum sensing molecules by the green seaweed Ulva

2007 ◽  
Vol 362 (1483) ◽  
pp. 1223-1233 ◽  
Author(s):  
Ian Joint ◽  
Karen Tait ◽  
Glen Wheeler
Keyword(s):  
Quorum Sensing ◽  
Calcium Influx ◽  
Calcium Signalling ◽  
Signal Molecules ◽  
Wild Type ◽  
Bacterial Quorum Sensing ◽  
Green Seaweed ◽  
Bacterial Quorum ◽  
Lines Of Evidence

The green seaweed Ulva has been shown to detect signal molecules produced by bacteria. Biofilms that release N -acylhomoserine lactones (AHLs) attract zoospores—the motile reproductive stages of Ulva . The evidence for AHL involvement is based on several independent lines of evidence, including the observation that zoospores are attracted to wild-type bacteria that produce AHLs but are not attracted to mutants that do not produce signal molecules. Synthetic AHL also attracts zoospores and the attraction is lost in the presence of autoinducer inactivation (AiiA) protein. The mechanism of attraction is not chemotactic but involves chemokinesis. When zoospores detect AHLs, the swimming rate is reduced and this results in accumulation of cells at the source of the AHL. It has been demonstrated that the detection of AHLs results in calcium influx into the zoospore. This is the first example of a calcium signalling event in a eukaryote in response to bacterial quorum sensing molecules. The role of AHLs in the ecology of Ulva is discussed. It is probable that AHLs act as cues for the settlement of zoospores, rather than being directly involved as a signalling mechanism.

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