Export of Rgg Quorum Sensing Peptides is Mediated by the PptAB ABC Transporter in Streptococcus Thermophilus Strain LMD-9

In streptococci, intracellular quorum sensing pathways are based on quorum-sensing systems that are responsible for peptide secretion, maturation, and reimport. These peptides then interact with Rgg or ComR transcriptional regulators in the Rap, Rgg, NprR, PlcR, and PrgX (RRNPP) family, whose members are found in Gram-positive bacteria. Short hydrophobic peptides (SHP) interact with Rgg whereas ComS peptides interact with ComR regulators. To date, in Streptococcus thermophilus, peptide secretion, maturation, and extracellular fate have received little attention, even though this species has several (at least five) genes encoding Rgg regulators and one encoding a ComR regulator. We studied pheromone export in this species, focusing our attention on PptAB, which is an exporter of signaling peptides previously identified in Enterococcus faecalis, pathogenic streptococci and Staphylococcus aureus. In the S. thermophilus strain LMD-9, we showed that PptAB controlled three regulation systems, two SHP/Rgg systems (SHP/Rgg1358 and SHP/Rgg1299), and the ComS/ComR system, while using transcriptional fusions and that PptAB helped to produce and export at least three different mature SHPs (SHP1358, SHP1299, and SHP279) peptides while using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Using a deep sequencing approach (RNAseq), we showed that the exporter PptAB, the membrane protease Eep, and the oligopeptide importer Ami controlled the transcription of the genes that were located downstream from the five non-truncated rgg genes as well as few distal genes. This led us to propose that the five non-truncated shp/rgg loci were functional. Only three shp genes were expressed in our experimental condition. Thus, this transcriptome analysis also highlighted the complex interconnected network that exists between SHP/Rgg systems, where a few homologous signaling peptides likely interact with different regulators.

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Identification and Characterization of Quorum-Quenching Activity of N-Acylhomoserine Lactonase from Coagulase-Negative Staphylococci

Antibiotics ◽

10.3390/antibiotics9080483 ◽

2020 ◽

Vol 9 (8) ◽

pp. 483

Author(s):

Tomohiro Morohoshi ◽

Yaoki Kamimura ◽

Nobutaka Someya

Keyword(s):

Quorum Sensing ◽

Opportunistic Pathogen ◽

Quorum Quenching ◽

Coagulase Negative Staphylococci ◽

Sensing Systems ◽

Genes Encoding ◽

Acyl Chains ◽

Gene Homologue ◽

Identification And Characterization

N-Acylhomoserine lactones (AHLs) are used as quorum-sensing signals in Gram-negative bacteria. Many genes encoding AHL-degrading enzymes have been cloned and characterized in various microorganisms. Coagulase-negative staphylococci (CNS) are present on the skin of animals and are considered low-virulent species. The AHL-lactonase gene homologue, ahlS, was present in the genomes of the CNS strains Staphylococcus carnosus, Staphylococcus haemolyticus, Staphylococcus saprophyticus, and Staphylococcus sciuri. We cloned the candidate ahlS homologue from six CNS strains into the pBBR1MCS5 vector. AhlS from the CNS strains showed a higher degrading activity against AHLs with short acyl chains compared to those with long acyl chains. AhlS from S. sciuri was expressed and purified as a maltose-binding protein (MBP) fusion. Pseudomonas aeruginosa is an opportunistic pathogen that regulates several virulence factors such as elastase and pyocyanin by quorum-sensing systems. When MBP-AhlS was added to the culture of P. aeruginosa PAO1, pyocyanin production and elastase activity were substantially reduced compared to those in untreated PAO1. These results demonstrate that the AHL-degrading activity of AhlS from the CNS strains can inhibit quorum sensing in P. aeruginosa PAO1.

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The Oligopeptide Transport System Is Essential for the Development of Natural Competence in Streptococcus thermophilus Strain LMD-9

Journal of Bacteriology ◽

10.1128/jb.00257-09 ◽

2009 ◽

Vol 191 (14) ◽

pp. 4647-4655 ◽

Cited By ~ 97

Author(s):

Rozenn Gardan ◽

Colette Besset ◽

Alain Guillot ◽

Christophe Gitton ◽

Véronique Monnet

Keyword(s):

Quorum Sensing ◽

Streptococcus Thermophilus ◽

Defined Medium ◽

Mass Spectrometry Analysis ◽

Transport Systems ◽

Label Free ◽

Spectrometry Analysis ◽

Proteomic Approach ◽

Liquid Chromatography Tandem Mass ◽

Oligopeptide Transport

ABSTRACT In gram-positive bacteria, oligopeptide transport systems, called Opp or Ami, play a role in nutrition but are also involved in the internalization of signaling peptides that take part in the functioning of quorum-sensing pathways. Our objective was to reveal functions that are controlled by Ami via quorum-sensing mechanisms in Streptococcus thermophilus, a nonpathogenic bacterium widely used in dairy technology in association with other bacteria. Using a label-free proteomic approach combining one-dimensional electrophoresis with liquid chromatography-tandem mass spectrometry analysis, we compared the proteome of the S. thermophilus LMD-9 to that of a mutant deleted for the subunits C, D, and E of the ami operon. Both strains were grown in a chemically defined medium (CDM) without peptides. We focused our attention on proteins that were no more detected in the ami deletion mutant. In addition to the three subunits of the Ami transporter, 17 proteins fulfilled this criterion and, among them, 7 were similar to proteins that have been identified as essential for transformation in S. pneumoniae. These results led us to find a condition of growth, the early exponential state in CDM, that allows natural transformation in S. thermophilus LMD-9 to turn on spontaneously. Cells were not competent in M17 rich medium. Furthermore, we demonstrated that the Ami transporter controls the triggering of the competence state through the control of the transcription of comX, itself controlling the transcription of late competence genes. We also showed that one of the two oligopeptide-binding proteins of strain LMD-9 plays the predominant role in the control of competence.

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Identification of Quorum-Sensing Molecules of N-Acyl-Homoserine Lactone in Gluconacetobacter Strains by Liquid Chromatography-Tandem Mass Spectrometry

Molecules ◽

10.3390/molecules24152694 ◽

2019 ◽

Vol 24 (15) ◽

pp. 2694

Author(s):

Ling-Pu Liu ◽

Long-Hui Huang ◽

Xiao-Tong Ding ◽

Lin Yan ◽

Shi-Ru Jia ◽

...

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

Quorum Sensing ◽

Tandem Mass Spectrometry ◽

Homoserine Lactone ◽

Tandem Mass ◽

Gram Negative ◽

Sensing Systems ◽

Chromatography Tandem Mass Spectrometry ◽

Liquid Chromatography Tandem Mass

Many Gram-negative bacteria can regulate gene expression in a cell density-dependent manner via quorum-sensing systems using N-acyl-homoserine lactones (AHLs), which are typical quorum-sensing signaling molecules, and thus modulate physiological characteristics. N-acyl-homoserine lactones are small chemical molecules produced at low concentrations by bacteria and are, therefore, difficult to detect. Here, a biosensor system method and liquid chromatography-tandem mass spectrometry were combined to detect and assay AHL production. As demonstrated by liquid chromatography-tandem mass spectrometry, Gluconacetobacter xylinus CGMCC No. 2955, a Gram-negative acetic acid-producing bacterium and a typical bacterial cellulose (BC) biosynthesis strain, produces six different AHLs, including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. Gluconacetobacter sp. strain SX-1, another Gram-negative acetic acid-producing bacterium, which can synthesize BC, produces seven different AHLs including N-acetyl-homoserine lactone, N-butanoyl-homoserine lactone, N-hexanoyl-homoserine lactone, N-3-oxo-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-dodecanoyl-homoserine lactone, and N-tetradecanoyl-homoserine lactone. These results lay the foundation for investigating the relationship between BC biosynthesis and quorum-sensing systems.

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Bacterial Communications in Implant Infections: A Target for an Intelligence War

The International Journal of Artificial Organs ◽

10.1177/039139880703000903 ◽

2007 ◽

Vol 30 (9) ◽

pp. 757-763 ◽

Cited By ~ 79

Author(s):

J.W. Costerton ◽

L. Montanaro ◽

C.r. Arciola

Keyword(s):

Quorum Sensing ◽

Bacterial Infections ◽

Bacterial Resistance ◽

Homoserine Lactone ◽

Bacterial Virulence ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Sensing Systems

The status of population density is communicated among bacteria by specific secreted molecules, called pheromones or autoinducers, and the control mechanism is called “quorum-sensing”. Quorum-sensing systems regulate the expression of a panel of genes, allowing bacteria to adapt to modified environmental conditions at a high density of population. The two known different quorum systems are described as the LuxR-LuxI system in gram-negative bacteria, which uses an N-acyl-homoserine lactone (AHL) as signal, and the agr system in gram-positive bacteria, which uses a peptide-tiolactone as signal and the RNAIII as effector molecules. Both in gram-negative and in gram-positive bacteria, quorum-sensing systems regulate the expression of adhesion mechanisms (biofilm and adhesins) and virulence factors (toxins and exoenzymes) depending on population cell density. In gram-negative Pseudomonas aeruginosa, analogs of signaling molecules such as furanone analogs, are effective in attenuating bacterial virulence and controlling bacterial infections. In gram-positive Staphylococcus aureus, the quorum-sensing RNAIII-inhibiting peptide (RIP), tested in vitro and in animal infection models, has been proved to inhibit virulence and prevent infections. Attenuation of bacterial virulence by quorum-sensing inhibitors, rather than by bactericidal or bacteriostatic drugs, is a highly attractive concept because these antibacterial agents are less likely to induce the development of bacterial resistance.

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Quorum-Sensing Control of Antibiotic Synthesis in Burkholderia thailandensis

Journal of Bacteriology ◽

10.1128/jb.00200-09 ◽

2009 ◽

Vol 191 (12) ◽

pp. 3909-3918 ◽

Cited By ~ 88

Author(s):

Breck A. Duerkop ◽

John Varga ◽

Josephine R. Chandler ◽

Snow Brook Peterson ◽

Jake P. Herman ◽

...

Keyword(s):

Quorum Sensing ◽

Gene Clusters ◽

Homoserine Lactone ◽

Evolutionary Divergence ◽

Peptide Antibiotics ◽

Burkholderia Thailandensis ◽

Antibiotic Synthesis ◽

Gram Positive Bacteria ◽

Sensing Systems ◽

Close Relatives

ABSTRACT The genome of Burkholderia thailandensis codes for several LuxR-LuxI quorum-sensing systems. We used B. thailandensis quorum-sensing deletion mutants and recombinant Escherichia coli to determine the nature of the signals produced by one of the systems, BtaR2-BtaI2, and to show that this system controls genes required for the synthesis of an antibiotic. BtaI2 is an acyl-homoserine lactone (acyl-HSL) synthase that produces two hydroxylated acyl-HSLs, N-3-hydroxy-decanoyl-HSL (3OHC10-HSL) and N-3-hydroxy-octanoyl-HSL (3OHC8-HSL). The btaI2 gene is positively regulated by BtaR2 in response to either 3OHC10-HSL or 3OHC8-HSL. The btaR2-btaI2 genes are located within clusters of genes with annotations that suggest they are involved in the synthesis of polyketide or peptide antibiotics. Stationary-phase cultures of wild-type B. thailandensis, but not a btaR2 mutant or a strain deficient in acyl-HSL synthesis, produced an antibiotic effective against gram-positive bacteria. Two of the putative antibiotic synthesis gene clusters require BtaR2 and either 3OHC10-HSL or 3OHC8-HSL for activation. This represents another example where antibiotic synthesis is controlled by quorum sensing, and it has implications for the evolutionary divergence of B. thailandensis and its close relatives Burkholderia pseudomallei and Burkholderia mallei.

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Multiple and Overlapping Functions of Quorum Sensing Proteins for Cell Specialization in Bacillus Species

Journal of Bacteriology ◽

10.1128/jb.00721-19 ◽

2020 ◽

Vol 202 (10) ◽

Cited By ~ 1

Author(s):

Abel Verdugo-Fuentes ◽

Gabriela Gastélum ◽

Jorge Rocha ◽

Mayra de la Torre

Keyword(s):

Quorum Sensing ◽

Bacillus Species ◽

Bacterial Populations ◽

Content Type ◽

Collective Behaviors ◽

Gram Positive Bacteria ◽

Signaling Peptides ◽

Moonlighting Proteins ◽

Sporulation Initiation ◽

Cell Specialization

ABSTRACT In bacterial populations, quorum sensing (QS) systems participate in the regulation of specialization processes and regulate collective behaviors that mediate interactions and allow survival of the species. In Gram-positive bacteria, QS systems of the RRNPP family (Rgg, Rap, NprR, PlcR, and PrgX) consist of intracellular receptors and their cognate signaling peptides. Two of these receptors, Rap and NprR, have regained attention in Bacillus subtilis and the Bacillus cereus group. Some Rap proteins, such as RapH and Rap60, are multifunctional and/or redundant in function, linking the specialization processes of sporulation and competence, as well as global expression changes in the transition phase in B. subtilis. NprR, an evolutionary intermediate between Rap and RRNPP transcriptional activators, is a bifunctional regulator that modulates sporulation initiation and activates nutrient scavenging genes. In this review, we discuss how these receptors switch between functions and connect distinct signaling pathways. Based on structural evidence, we propose that RapH and Rap60 should be considered moonlighting proteins. Additionally, we analyze an evolutionary and ecological perspective to understand the multifunctionality and functional redundancy of these regulators in both Bacillus spp. and non-Bacillus Firmicutes. Understanding the mechanistic, structural, ecological, and evolutionary basis for the multifunctionality and redundancy of these QS systems is a key step for achieving the development of innovative technologies for health and agriculture.

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Quorum Sensing Regulation in Phytopathogenic Bacteria

Microorganisms ◽

10.3390/microorganisms9020239 ◽

2021 ◽

Vol 9 (2) ◽

pp. 239

Author(s):

Julie Baltenneck ◽

Sylvie Reverchon ◽

Florence Hommais

Keyword(s):

Quorum Sensing ◽

Homoserine Lactone ◽

Signal Molecules ◽

Signal Molecule ◽

Bacterial Populations ◽

Phytopathogenic Bacteria ◽

Sensing Systems ◽

Expression Of Genes ◽

Genes Encoding ◽

Diffusible Signal Factor

Quorum sensing is a type of chemical communication by which bacterial populations control expression of their genes in a coordinated manner. This regulatory mechanism is commonly used by pathogens to control the expression of genes encoding virulence factors and that of genes involved in the bacterial adaptation to variations in environmental conditions. In phytopathogenic bacteria, several mechanisms of quorum sensing have been characterized. In this review, we describe the different quorum sensing systems present in phytopathogenic bacteria, such as those using the signal molecules named N-acyl-homoserine lactone (AHL), diffusible signal factor (DSF), and the unknown signal molecule of the virulence factor modulating (VFM) system. We focus on studies performed on phytopathogenic bacteria of major importance, including Pseudomonas, Ralstonia, Agrobacterium, Xanthomonas, Erwinia, Xylella,Dickeya, and Pectobacterium spp. For each system, we present the mechanism of regulation, the functions targeted by the quorum sensing system, and the mechanisms by which quorum sensing is regulated.

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RRNPP_detector: a tool to detect RRNPP quorum sensing systems in chromosomes, plasmids and phages of gram-positive bacteria

10.1101/2021.08.18.456871 ◽

2021 ◽

Author(s):

Charles Bernard ◽

Yanyan Li ◽

Eric Bapteste ◽

Philippe Lopez

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Gene Clusters ◽

Dependent Manner ◽

Biosynthetic Gene Clusters ◽

Gram Positive ◽

Gram Positive Bacteria ◽

Sensing Systems ◽

Behavioral Transitions ◽

Intracellular Receptor

Gram-positive bacteria (e.g. Firmicutes) and their mobile genetic elements (plasmids, bacteriophages) encode peptide-based quorum sensing systems (QSSs) that regulate behavioral transitions in a density-dependent manner. In their simplest form, termed "RRNPP", these QSSs are composed of two adjacent genes: a communication propeptide and its cognate intracellular receptor. Despite the prime importance of RRNPP QSSs in the regulation of key biological pathways such as virulence, sporulation or biofilm formation in bacteria, conjugation in plasmids or lysogeny in temperate bacteriophages, no tools exist to predict their presence in target genomes/mobilomes. Here, we introduce RRNPP_detector, a software to predict RRNPP QSSs in chromosomes, plasmids and bacteriophages of gram-positive bacteria, available at https://github.com/TeamAIRE/RRNPP_detector. RRNPP_detector does not rely on homology searches but on a signature of multiple criteria, which are common between distinct families of experimentally-validated RRNPP QSSs. Because this signature is generic while specific to the canonical mechanism of RRNPP quorum sensing, it enables the discovery of novel RRNPP QSSs and thus of novel "languages" of biocommunication. Applying RRNPP_detector against complete genomes of viruses and Firmicutes available on the NCBI, we report a potential 7.5-fold expansion of RRNPP QSS diversity, alternative secretion-modes for certain candidate QSS propeptides, "bilingual" bacteriophages and plasmids, as well as predicted chromosomal and plasmidic Biosynthetic-Gene-Clusters regulated by QSSs.

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