scholarly journals Two Homologous Agr-Like Quorum-Sensing Systems Cooperatively Control Adherence, Cell Morphology, and Cell Viability Properties in Lactobacillus plantarum WCFS1

2008 ◽  
Vol 190 (23) ◽  
pp. 7655-7665 ◽  
Author(s):  
Toshio Fujii ◽  
Colin Ingham ◽  
Jiro Nakayama ◽  
Marke Beerthuyzen ◽  
Ryoko Kunuki ◽  
...  
Keyword(s):  
Cell Wall ◽  
Quorum Sensing ◽  
Lactobacillus Plantarum ◽  
Cell Morphology ◽  
Response Regulator ◽  
Regulatory System ◽  
Mass Spectrometry Analysis ◽  
Cell Wall Polysaccharide ◽  
Transcription Analysis ◽  
Spectrometry Analysis

ABSTRACT A two-component regulatory system of Lactobacillus plantarum, encoded by genes designated lamK and lamR (hpk10 and rrp10), was studied. The lamK and lamR genes encode proteins which are highly homologous to the quorum-sensing histidine kinase LamC and the response regulator LamA, respectively. Transcription analysis of the lamKR operon and the lamBDCA operon and liquid chromatography-mass spectrometry analysis of production of the LamD558 autoinducing peptide were performed for ΔlamA, ΔlamR, ΔlamA ΔlamR deletion mutants and a wild-type strain. The results suggested that lamA and lamR are cooperating genes. In addition, typical phenotypes of the ΔlamA mutant, such as reduced adherence to glass surfaces and filamentous cell morphology, were enhanced in the ΔlamA ΔlamR mutant. Microarray analysis suggested that the same cell wall polysaccharide synthesis genes, stress response-related genes, and cell wall protein-encoding genes were affected in the ΔlamA and ΔlamA ΔlamR mutants. However, the regulation ratio was more significant for the ΔlamA ΔlamR mutant, indicating the cooperative effect of LamA and LamR.

scholarly journals Quorum-Sensing Regulation of Constitutive Plantaricin by Lactobacillus plantarum Strains under a Model System for Vegetables and Fruits

2013 ◽  
Vol 80 (2) ◽  
pp. 777-787 ◽  
Author(s):  
Carlo G. Rizzello ◽  
Pasquale Filannino ◽  
Raffaella Di Cagno ◽  
Maria Calasso ◽  
Marco Gobbetti
Keyword(s):  
Quorum Sensing ◽  
Lactobacillus Plantarum ◽  
Antimicrobial Activities ◽  
Model System ◽  
Mass Spectrometry Analysis ◽  
Carrot Juice ◽  
Content Type ◽  
Spectrometry Analysis ◽  
Vegetables And Fruits

ABSTRACTThis study aimed at investigating the regulatory system of bacteriocin synthesis byLactobacillus plantarumstrains in vegetables and fruits in a model system. Sterile and neutralized cell-free supernatant (CFS) fromL. plantarumstrains grown in MRS broth showedin vitroantimicrobial activities toward various indicator strains. The highest activity was that ofL. plantarumC2. The antimicrobial activity was further assayed on vegetable and fruit agar plates (solid conditions) and in juices (liquid conditions). A regulatory mechanism of bacteriocin synthesis via quorum sensing was hypothesized. The synthesis of antimicrobial compounds seemed to be constitutive under solid conditions of growth on vegetable and fruit agar plates. In contrast, it depended on the size of the inoculum whenL. plantarumC2 was grown in carrot juice. Only the inoculum of ca. 9.0 log CFU ml−1produced detectable activity. The genesplnA,plnEF,plnG, andplnHwere found in allL. plantarumstrains. The genesplnJKandplnNwere detected in only three or four strains. Reverse-phase high-performance liquid chromatography purification and mass spectrometry analysis revealed the presence of a mixture of eight peptides in the most active fraction of the CFS fromL. plantarumC2. Active peptides were encrypted into bacteriocin precursors, such as plantaricins PlnJ/K and PlnH and PlnG, which are involved in the ABC transport system. A real-time PCR assay showed an increase in the expression ofplnJKandplnGduring growth ofL. plantarumC2 in carrot juice.

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

2009 ◽  
Vol 191 (14) ◽  
pp. 4647-4655 ◽  
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.

scholarly journals Roles of Minor Pilin Subunits Spy0125 and Spy0130 in the Serotype M1 Streptococcus pyogenes Strain SF370

2010 ◽  
Vol 192 (18) ◽  
pp. 4651-4659 ◽  
Author(s):  
Wendy D. Smith ◽  
Jonathan A. Pointon ◽  
Emily Abbot ◽  
Hae Joo Kang ◽  
Edward N. Baker ◽  
...  
Keyword(s):  
Cell Wall ◽  
Streptococcus Pyogenes ◽  
Human Keratinocytes ◽  
Mass Spectrometry Analysis ◽  
Deletion Mutants ◽  
Wild Type ◽  
Spectrometry Analysis ◽  
Liquid Chromatography Tandem Mass ◽  
Protein Adhesion ◽  
Culture Supernatants

ABSTRACT Adhesive pili on the surface of the serotype M1 Streptococcus pyogenes strain SF370 are composed of a major backbone subunit (Spy0128) and two minor subunits (Spy0125 and Spy0130), joined covalently by a pilin polymerase (Spy0129). Previous studies using recombinant proteins showed that both minor subunits bind to human pharyngeal (Detroit) cells (A. G. Manetti et al., Mol. Microbiol. 64:968-983, 2007), suggesting both may act as pilus-presented adhesins. While confirming these binding properties, studies described here indicate that Spy0125 is the pilus-presented adhesin and that Spy0130 has a distinct role as a wall linker. Pili were localized predominantly to cell wall fractions of the wild-type S. pyogenes parent strain and a spy0125 deletion mutant. In contrast, they were found almost exclusively in culture supernatants in both spy0130 and srtA deletion mutants, indicating that the housekeeping sortase (SrtA) attaches pili to the cell wall by using Spy0130 as a linker protein. Adhesion assays with antisera specific for individual subunits showed that only anti-rSpy0125 serum inhibited adhesion of wild-type S. pyogenes to human keratinocytes and tonsil epithelium to a significant extent. Spy0125 was localized to the tip of pili, based on a combination of mutant analysis and liquid chromatography-tandem mass spectrometry analysis of purified pili. Assays comparing parent and mutant strains confirmed its role as the adhesin. Unexpectedly, apparent spontaneous cleavage of a labile, proline-rich (8 of 14 residues) sequence separating the N-terminal ∼1/3 and C-terminal ∼2/3 of Spy0125 leads to loss of the N-terminal region, but analysis of internal spy0125 deletion mutants confirmed that this has no significant effect on adhesion.

scholarly journals Bacteriophage φEf11 ORF28 Endolysin, a Multifunctional Lytic Enzyme with Properties Distinct from All Other IdentifiedEnterococcus faecalisPhage Endolysins

2019 ◽  
Vol 85 (13) ◽  
Author(s):  
Hongming Zhang ◽  
Bettina A. Buttaro ◽  
Derrick E. Fouts ◽  
Salar Sanjari ◽  
Bradley S. Evans ◽  
...  
Keyword(s):  
Cell Wall ◽  
Enterococcus Faecalis ◽  
Amino Acid Identity ◽  
Lytic Infection ◽  
Mass Spectrometry Analysis ◽  
Lytic Enzyme ◽  
Lytic Enzymes ◽  
Content Type ◽  
Spectrometry Analysis ◽  
Wide Range

ABSTRACTϕEf11 is a temperateSiphoviridaebacteriophage that infects strains ofEnterococcus faecalis. The ϕEf11 genome, encompassing 65 open reading frames (ORFs), is contained within 42,822 bp of DNA. Within this genome, a module of six lysis-related genes was identified. Based upon sequence homology, one of these six genes, ORF28, was predicted to code for anN-acetylmuramoyl-l-alanine amidase endolysin of 46.133 kDa, composed of 421 amino acids. The PCR-amplified ORF28 was cloned and expressed, and the resulting gene product was affinity purified to homogeneity. The purified protein was obtained from a fusion protein that exhibited a molecular mass of 72.5 kDa, consistent with a 46.1-kDa protein combined with a fused 26.5-kDa glutathioneS-transferase tag. It produced rapid, profound lysis inE. faecalispopulations and was active against 73 of 103 (71%)E. faecalisstrains tested. In addition, it caused substantial destruction ofE. faecalisbiofilms. The lysin was quite stable, retaining its activity for three years in refrigerated storage, was stable over a wide range of pHs, and was unaffected by the presence of a reducing agent; however, it was inhibited by increasing concentrations of Ca2+. Liquid chromatography-mass spectrometry analysis ofE. faecaliscell wall digestion products produced by the ORF28 endolysin indicated that the lysin acted as anN-acetylmuramidase, an endo-β-N-acetylglucosaminidase, and an endopeptidase, rather than anN-acetylmuramoyl-l-alanine amidase. The ϕEf11 ORF28 lysin shared 10% to 37% amino acid identity with the lytic enzymes of all other characterizedE. faecalisbacteriophages.IMPORTANCEThe emergence of multidrug-resistant pathogenic microorganisms has brought increasing attention to the urgent need for the development of alternative antimicrobial strategies. One such alternative to conventional antibiotics employs lytic enzymes (endolysins) that are produced by bacteriophages in the course of lytic infection. During lytic infection by a bacteriophage, these enzymes hydrolyze the cell wall peptidoglycan, resulting in the lysis of the host cell. However, external endolysin application can result in lysis from without. In this study, we have cloned, expressed, purified, and characterized an endolysin produced by a bacteriophage infecting strains ofEnterococcus faecalis. The lysin is broadly active against most of the testedE. faecalisstrains and exhibits multifunctional enzymatic specificities that differ from all other characterized endolysins produced byE. faecalisbacteriophages.

scholarly journals Function of the bacteriophytochrome BphP in the RpoS/Las quorum-sensing network of Pseudomonas aeruginosa

Microbiology ◽  
2011 ◽  
Vol 157 (6) ◽  
pp. 1651-1664 ◽  
Author(s):  
Katalin Barkovits ◽  
Britta Schubert ◽  
Sabrina Heine ◽  
Maurice Scheer ◽  
Nicole Frankenberg-Dinkel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Response Regulator ◽  
Red Light ◽  
Regulatory System ◽  
Global Gene Expression ◽  
Opportunistic Pathogen ◽  
Pleiotropic Effect ◽  
Genes Encoding

The bacterial phytochrome of Pseudomonas aeruginosa (PaBphP) is an in vitro-active red/far-red light sensor histidine kinase of a two-component regulatory system. Despite solid biochemical data, its function in this heterotrophic, opportunistic pathogen is still unknown. Previous studies established that the genes encoding the two necessary phytochrome components BphO, a chromophore-producing haem oxygenase, and BphP, the apo-phytochrome, are co-transcribed in a bicistronic operon. Transcription has been shown to be induced in the stationary phase and to be dependent on the alternative sigma factor RpoS. Here we show an additional regulation of bphP expression through the quorum-sensing (QS) regulator LasR. This regulation is also reflected in a combination of expression profile experiments and proteome analyses of wild-type and phytochrome-deficient strains. While PaBphP has a pleiotropic effect on global gene expression, 66 % of the downregulated genes in the phytochrome mutant display a link to the Las QS system. Most of these genes seem to be indirectly regulated by LasR through BphP and the unknown response regulator BphR. A model of phytochrome function within the Las QS network is presented.

scholarly journals Enterobacter cancerogenus produces short chain N-3-oxo-acylhomoserine lactones quorum sensing molecules

2015 ◽  
Author(s):  
Kok-Gan Chan ◽  
Wen-Si Tan
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Resolution ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Mass Spectrometry Analysis ◽  
Liquid Chromatography Mass Spectrometry ◽  
Spectrometry Analysis ◽  
Synthesis Activity

Enterobacter cancerogenus strain M004 genome size is 5.67 Mb. Here, its luxI homologue, designated as ecnI which is ecnI gene (633 bp) was cloned and overexpressed. Its AHL synthesis activity was verified using the high-resolution liquid chromatography-mass spectrometry analysis revealed the production of N-(3-oxo-hexanoyl)-L-homoserine lactone (3-oxo-C6-HSL) and N-(3-oxo-hexanoyl)-L-homoserine lactone (3-oxo-C8-HSL). The cloning and characterization of luxI homologue of E. cancerogenus strain M004 was firstly reported here.

scholarly journals Quorum-Sensing Regulation of the Production of Blp Bacteriocins in Streptococcus thermophilus

2007 ◽  
Vol 189 (20) ◽  
pp. 7195-7205 ◽  
Author(s):  
Laetitia Fontaine ◽  
Céline Boutry ◽  
Eric Guédon ◽  
Alain Guillot ◽  
Mariam Ibrahim ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Response Regulator ◽  
Regulatory System ◽  
Streptococcus Thermophilus ◽  
Peptide Transporter ◽  
Transcriptional Level ◽  
Direct Repeats ◽  
Promoter Regions ◽  
Pheromone Concentration ◽  
Immunity Genes

ABSTRACT The blp gene cluster identified in the genome sequences of Streptococcus thermophilus (blp St) LMG18311, CNRZ1066, and LMD-9 displays all the characteristics of a class II bacteriocin locus. In the present study, we showed that the blp St locus is only fully functional in strain LMD-9 and regulates the production of antimicrobial peptides that inhibit strains LMG18311 and CNRZ1066. The blp St cluster of LMD-9 contains 23 genes that are transcriptionally organized in six operons: blpABC St (peptide transporter genes and pheromone gene); blpRH St (two-component regulatory system genes); blpD St-orf1, blpU St-orf3, and blpE-F St (bacteriocin precursors and immunity genes); and blpG-X St (unknown function). All the operons, except the regulatory unit blpRH St, were shown to be coregulated at the transcriptional level by a quorum-sensing mechanism involving the mature S. thermophilus pheromone BlpC* (BlpC*St), which was extracellularly detected as two active forms (30 and 19 amino acids). These operons are differentially transcribed depending on growth phase and pheromone concentration. They all contain a motif with two imperfect direct repeats in their mapped promoter regions that could serve as binding sites of the response regulator BlpRSt. Through the construction of deletion mutants, the blp St locus of strain LMD-9 was shown to encode all the essential functions associated with bacteriocin production, quorum-sensing regulation, and immunity.

scholarly journals Regulation of the PcoI/PcoR quorum-sensing system in Pseudomonas fluorescens 2P24 by the PhoP/PhoQ two-component system

Microbiology ◽  
2009 ◽  
Vol 155 (1) ◽  
pp. 124-133 ◽  
Author(s):  
Qing Yan ◽  
Wei Gao ◽  
Xiao-Gang Wu ◽  
Li-Qun Zhang
Keyword(s):  
Quorum Sensing ◽  
Pseudomonas Fluorescens ◽  
Promoter Activity ◽  
Response Regulator ◽  
Random Mutagenesis ◽  
Gene Promoter ◽  
Regulatory System ◽  
Amino Acid Sequences ◽  
Signal Molecules ◽  
Two Component

A quorum-sensing locus, pcoI/pcoR, which is involved in the regulation of root colonization and plant disease-suppressive ability, was previously identified in Pseudomonas fluorescens 2P24. In this study, we performed random mutagenesis using mini-Tn5 in order to screen the upstream transcriptional regulators of pcoI, a biosynthase gene responsible for the synthesis of N-acylhomoserine lactone signal molecules. Two mutants, PM400 and PM410, with elevated pcoI gene promoter activity, were identified from ∼10 000 insertion clones. The amino acid sequences of the interrupted genes in these two mutants were highly similar to PhoQ, a sensor protein of the two-component regulatory system PhoP/PhoQ, which responds to environmental Mg2+ starvation and regulates virulence in Salmonella typhimurium and antimicrobial peptide resistance in Pseudomonas aeruginosa. The promoter activity of pcoI was also induced under low-Mg2+ conditions in the 2P24 strain of P. fluorescens. Deletion mutagenesis and complementation experiments demonstrated that the transcription of pcoI was negatively regulated by the sensor PhoQ but positively regulated by the response regulator PhoP. Genetic evidence also indicated that transcription of the outer-membrane protein gene oprH was induced by Mg2+ starvation through regulation of the wild-type PhoP/PhoQ system. Additionally, PhoQ was involved in biofilm formation by 2P24 under low-Mg2+ conditions through a PhoP-independent pathway.

scholarly journals Regulation of the N-Acyl Homoserine Lactone-Dependent Quorum-Sensing System in Rhizosphere Pseudomonas putida WCS358 and Cross-Talk with the Stationary-Phase RpoS Sigma Factor and the Global Regulator GacA

2004 ◽  
Vol 70 (9) ◽  
pp. 5493-5502 ◽  
Author(s):  
Iris Bertani ◽  
Vittorio Venturi
Keyword(s):  
Quorum Sensing ◽  
Stationary Phase ◽  
Pseudomonas Putida ◽  
Family Member ◽  
Growth Phase ◽  
Sigma Factor ◽  
Response Regulator ◽  
Expression Profiles ◽  
Regulatory System ◽  
Homoserine Lactone

ABSTRACT Quorum sensing is a cell population-density dependent regulatory system which in gram-negative bacteria often involves the production and detection of N-acyl homoserine lactones (AHLs). Some Pseudomonas putida strains have been reported to produce AHLs, and one quorum-sensing locus has been identified. However, it appears that the majority of strains do not produce AHLs. In this study we report the identification and regulation of the AHL-dependent system of rhizosphere P. putida WCS358. This system is identical to the recently identified system of P. putida strain IsoF and very similar to the las system of Pseudomonas aeruginosa. It is composed of three genes, the luxI family member ppuI, the putative repressor rsaL, and the luxR family member ppuR. A genomic ppuR::Tn5 mutant of strain WCS358 was identified by its inability to produce AHLs when it was cross-streaked in close proximity to an AHL biosensor, whereas an rsaL::Tn5 genomic mutant was identified by its ability to overproduce AHL molecules. Using transcriptional promoter fusions, we studied expression profiles of the rsaL, ppuI, and ppuR promoters in various genetic backgrounds. At the onset of the stationary phase, the autoinducer synthase ppuI gene expression is under positive regulation by PpuR-AHL and under negative regulation by RsaL, indicating that the molecules could be in competition for binding at the ppuI promoter. In genomic rsaL::Tn5 mutants ppuI expression and production of AHL levels increased dramatically; however, both processes were still under growth phase regulation, indicating that RsaL is not involved in repressing AHL production at low cell densities. The roles of the global response regulator GacA and the stationary-phase sigma factor RpoS in the regulation of the AHL system at the onset of the stationary phase were also investigated. The P. putida WCS358 gacA gene was cloned and inactivated in the genome. It was determined that the three global regulatory systems are closely linked, with quorum sensing and RpoS regulating each other and GacA positively regulating ppuI expression. Studies of the regulation of AHL quorum-sensing systems have lagged behind other studies and are important for understanding how these systems are integrated into the overall growth phase and metabolic status of the cells.

Production of new extracellular glycolipids by a strain ofCellulomonas cellulans(Oerskovia xanthineolytica) and their structural characterization

1998 ◽  
Vol 44 (3) ◽  
pp. 238-243 ◽  
Author(s):  
S Arino ◽  
R Marchal ◽  
J -P Vandecasteele
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acids ◽  
Gas Chromatography ◽  
Cell Wall ◽  
Culture Medium ◽  
Soil Samples ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Spectrometry Analysis ◽  
Hydrolysis Of

Glycolipid-producing bacteria were isolated from soil samples. One of the strains, identified as Cellulomonas cellulans (Oerskovia xanthineolytica), was found to produce significant amounts of unusual extracellular glycolipids, which were shown to be composed of at least 11 individual compounds. Hydrolysis of the glycolipid mixture and gas chromatography - mass spectrometry analysis revealed the presence of fatty acids and hydroxy fatty acids ranging from C10to C18, 16 of which were identified. The glycidic moiety consisted of glucose, rhamnose, and ribose. The same sugars were found to be present in the cell wall of Cellulomonas cellulans, which also contained polar lipids including glycolipids. During strain cultivation, glycolipid excretion was stimulated when nitrogen was exhausted from the culture medium. In these conditions, the production in fermenters on glycerol, expressed in glucose equivalents, reached 8.9 g/L. Cell hydrophobicity, which rose to 95% during the growth phase, decreased to 50% during the production phase. The overall results show that the bacterial cell wall is involved in the synthesis of these new extracellular glycolipids.Key words: glycolipid, excretion, Cellulomonas cellulans, Oerskovia xanthineolytica, cell wall.

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