scholarly journals Quorum Sensing and Spoilage Potential of Psychrotrophic Enterobacteriaceae Isolated from Milk

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Maurilio Lopes Martins ◽  
Uelinton Manoel Pinto ◽  
Katharina Riedel ◽  
Maria Cristina Dantas Vanetti
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
16S Rdna ◽  
Aeromonas Hydrophila ◽  
Vibrio Harveyi ◽  
Raw Milk ◽  
Homoserine Lactone ◽  
Positive Control ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones

The 16S rDNA of six psychrotrophic Enterobacteriaceae isolated from cold raw milk were sequenced and the isolate 039 was identified asPantoeasp., isolates 059, 068, and 071 were identified asHafnia alvei, 067 was identified asEnterobactersp., and 099 was identified asAeromonas hydrophila. They presented different spoilage potentials in milk withA. hydrophila099 being the most deteriorative. OnlyPantoeasp. 039 was not able to induce the quorum sensing monitor strains of acyl homoserine lactones (AHLs). ThehalIgene, which encodes the AHL synthase inH. alvei, was identified in the isolates 059, 067, 068, and 071. After initial sequencing characterization and cloning, this gene showed its function by the heterologous synthesis of N-hexanoyl-DL-homoserine lactone and N-3-oxohexanoyl-L-homoserine lactone inEscherichia coli. In addition to producing AHLs,A. hydrophila099 produced AI-2 in higher level than the assay’s positive controlVibrio harveyiBB120. Therefore, Enterobacteriaceae strains isolated from cooled raw milk produce a rich array of signaling molecules that may influence bacterial traits in the milk environment.

Structure of the Escherichia coli Quorum Sensing Protein SdiA: Activation of the Folding Switch by Acyl Homoserine Lactones

2006 ◽  
Vol 355 (2) ◽  
pp. 262-273 ◽  
Author(s):  
Yong Yao ◽  
Maria A. Martinez-Yamout ◽  
Tobin J. Dickerson ◽  
Andrew P. Brogan ◽  
Peter E. Wright ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Quorum Sensing ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones

scholarly journals Long-Chain Acyl-Homoserine Lactone Quorum-Sensing Regulation of Rhodobacter capsulatus Gene Transfer Agent Production

2002 ◽  
Vol 184 (23) ◽  
pp. 6515-6521 ◽  
Author(s):  
Amy L. Schaefer ◽  
Terumi A. Taylor ◽  
J. Thomas Beatty ◽  
E. P. Greenberg
Keyword(s):  
Gene Transfer ◽  
Quorum Sensing ◽  
Rhodobacter Capsulatus ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Chain Acyl ◽  
Gene Transfer Agent ◽  
Long Chain

ABSTRACT Many proteobacteria use acyl-homoserine lactones as quorum-sensing signals. Traditionally, biological detection systems have been used to identify bacteria that produce acyl-homoserine lactones, although the specificities of these detection systems can limit discovery. We used a sensitive approach that did not require a bioassay to detect production of long-acyl-chain homoserine lactone production by Rhodobacter capsulatus and Paracoccus denitrificans. These long-chain acyl-homoserine lactones are not readily detected by standard bioassays. The most abundant acyl-homoserine lactone was N-hexadecanoyl-homoserine lactone. The long-chain acyl-homoserine lactones were concentrated in cells but were also found in the culture fluid. An R. capsulatus gene responsible for long-chain acyl-homoserine lactone synthesis was identified. A mutation in this gene, which we named gtaI, resulted in decreased production of the R. capsulatus gene transfer agent, and gene transfer agent production was restored by exogenous addition of N-hexadecanoyl-homoserine lactone. Thus, long-chain acyl-homoserine lactones serve as quorum-sensing signals to enhance genetic exchange in R. capsulatus.

scholarly journals The GCR1 and GPA1 Participate in Promotion of Arabidopsis Primary Root Elongation Induced by N-Acyl-Homoserine Lactones, the Bacterial Quorum-Sensing Signals

2012 ◽  
Vol 25 (5) ◽  
pp. 677-683 ◽  
Author(s):  
Fang Liu ◽  
Ziriu Bian ◽  
Zhenhua Jia ◽  
Qian Zhao ◽  
Shuishan Song
Keyword(s):  
Quorum Sensing ◽  
Root Elongation ◽  
Primary Root ◽  
Homoserine Lactone ◽  
Collective Behaviors ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum ◽  
Quorum Sensing Signals

Many gram-negative bacteria use N-acyl-homoserine lactones (AHL) as quorum-sensing signals to coordinate their collective behaviors. Accumulating evidence indicates that plants can respond to AHL. However, little is known about the molecular mechanism of plants reacting to these bacterial signals. In this study, we show that the treatment of Arabidopsis roots with N-3-oxo-hexanoyl-homoserine lactone (3OC6-HSL) and N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL) resulted in significant root elongation. The genetic analysis revealed that the T-DNA insertional mutants of gcr1, encoding a G-protein-coupled receptor GCR1, were insensitive to 3OC6-HSL or 3OC8-HSL in assays of root growth. The loss-of-function mutants of the sole canonical Gα subunit GPA1 showed no response to AHL promotion of root elongation whereas Gα gain-of-function plants overexpressing either the wild type or a constitutively active version of Arabidopsis Gα exhibited the exaggerated effect on root elongation caused by AHL. Furthermore, the expression of GCR1 and GPA1 were significantly upregulated after plants were contacted with both AHL. Taken together, our results suggest that GCR1 and GPA1 are involved in AHL-mediated elongation of Arabidopsis roots. This provides insight into the mechanism of plant responses to bacterial quorum-sensing signals.

scholarly journals Octanoyl-Homoserine Lactone Is the Cognate Signal for Burkholderia mallei BmaR1-BmaI1 Quorum Sensing

2007 ◽  
Vol 189 (14) ◽  
pp. 5034-5040 ◽  
Author(s):  
Breck A. Duerkop ◽  
Ricky L. Ulrich ◽  
E. Peter Greenberg
Keyword(s):  
Quorum Sensing ◽  
Promoter Region ◽  
Homoserine Lactone ◽  
Burkholderia Mallei ◽  
Homoserine Lactones ◽  
E Coli ◽  
Cognate Receptor ◽  
System A ◽  
Acyl Homoserine Lactones ◽  
Quorum Sensing Signals

ABSTRACT Acyl-homoserine lactones (HSLs) serve as quorum-sensing signals for many Proteobacteria. Members of the LuxI family of signal generators catalyze the production of acyl-HSLs, which bind to a cognate receptor in the LuxR family of transcription factors. The obligate animal pathogen Burkholderia mallei produces several acyl-HSLs, and the B. mallei genome has four luxR and two luxI homologs, each of which has been established as a virulence factor. To begin to delineate the relevant acyl-HSL signals for B. mallei LuxR homologs, we analyzed the BmaR1-BmaI1 system. A comparison of acyl-HSL profiles from B. mallei ATCC 23344 and a B. mallei bmaI1 mutant indicates that octanoyl-HSL synthesis is BmaI1 dependent. Furthermore, octanoyl-HSL is the predominant acyl-HSL produced by BmaI1 in recombinant Escherichia coli. The synthesis of soluble BmaR1 in recombinant E. coli requires octanoyl-HSL or decanoyl-HSL. Insoluble aggregates of BmaR1 are produced in the presence of other acyl-HSLs and in the absence of acyl-HSLs. The bmaI1 promoter is activated by BmaR1 and octanoyl-HSL, and a 20-bp inverted repeat in the bmaI1 promoter is required for bmaI1 activation. Purified BmaR1 binds to this promoter region. These findings implicate octanoyl-HSL as the signal for BmaR1-BmaI1 quorum sensing and show that octanoyl-HSL and BmaR1 activate bmaI1 transcription.

scholarly journals Control of Quorum Sensing by a Burkholderia pseudomallei Multidrug Efflux Pump

2007 ◽  
Vol 189 (11) ◽  
pp. 4320-4324 ◽  
Author(s):  
Ying Ying Chan ◽  
Hao Sheng Bian ◽  
Theresa May Chin Tan ◽  
Margrith E. Mattmann ◽  
Grant D. Geske ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Burkholderia Pseudomallei ◽  
Efflux Pump ◽  
Homoserine Lactone ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Homoserine Lactones ◽  
Extracellular Secretion ◽  
Sensing Systems ◽  
Acyl Homoserine Lactones

ABSTRACT The Burkholderia pseudomallei KHW quorum-sensing systems produced N-octanoyl-homoserine lactone, N-decanoyl-homoserine lactone, N-(3-hydroxy)-octanoyl-homoserine lactone, N-(3-hydroxy)-decanoyl-homoserine lactone, N-(3-oxo)-decanoyl-homoserine lactone, and N-(3-oxo)-tetradecanoyl-homoserine lactone. The extracellular secretion of these acyl-homoserine lactones is dependent absolutely on the function of the B. pseudomallei BpeAB-OprB efflux pump.

scholarly journals Virulence of Burkholderia mallei Quorum-Sensing Mutants

2013 ◽  
Vol 81 (5) ◽  
pp. 1471-1478 ◽  
Author(s):  
Charlotte Majerczyk ◽  
Loren Kinman ◽  
Tony Han ◽  
Richard Bunt ◽  
E. Peter Greenberg
Keyword(s):  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Mouse Lung ◽  
Depth Information ◽  
Acyl Homoserine Lactone ◽  
Burkholderia Mallei ◽  
Content Type ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones

ABSTRACTManyProteobacteriause acyl-homoserine lactone-mediated quorum-sensing (QS) to activate specific sets of genes as a function of cell density. QS often controls the virulence of pathogenic species, and in fact a previous study indicated that QS was important forBurkholderia malleimouse lung infections. To gain in-depth information on the role of QS inB. malleivirulence, we constructed and characterized a mutant ofB. malleistrain GB8 that was unable to make acyl-homoserine lactones. The QS mutant showed virulence equal to that of its wild-type parent in an aerosol mouse infection model, and growth in macrophages was indistinguishable from that of the parent strain. Furthermore, we assessed the role of QS inB. malleiATCC 23344 by constructing and characterizing a mutant strain producing AiiA, a lactonase enzyme that degrades acyl-homoserine lactones. Although acyl-homoserine lactone levels in cultures of this strain are very low, it showed full virulence. Contrary to the previous report, we conclude that QS is not required for acuteB. malleiinfections of mice. QS may be involved in some stage of chronic infections in the natural host of horses, or the QS genes may be remnants of the QS network inB. pseudomalleifrom which this host-adapted pathogen evolved.

scholarly journals Immunomodulatory and Protective Roles of Quorum-Sensing Signaling MoleculesN-Acyl Homoserine Lactones during Infection of Mice with Aeromonas hydrophila

2011 ◽  
Vol 79 (7) ◽  
pp. 2646-2657 ◽  
Author(s):  
Bijay K. Khajanchi ◽  
Michelle L. Kirtley ◽  
Sheri M. Brackman ◽  
Ashok K. Chopra
Keyword(s):  
Immune Response ◽  
Quorum Sensing ◽  
Aeromonas Hydrophila ◽  
Bacterial Load ◽  
Content Type ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Underlying Mechanisms ◽  
Mouse Model Of Infection ◽  
Phosphate Buffered Saline

ABSTRACTAeromonas hydrophilaleads to both intestinal and extraintestinal infections in animals and humans, and the underlying mechanisms leading to mortality are largely unknown. By using a septicemic mouse model of infection, we showed that animals challenged withA. hydrophiladie because of kidney and liver damage, hypoglycemia, and thrombocytopenia. Pretreatment of animals with quorum-sensing-associated signaling moleculesN-acyl homoserine lactones (AHLs), such as butanoyl and hexanoyl homoserine lactones (C4- and C6-HSLs), as well asN-3-oxododecanoyl (3-oxo-C12)-HSL, prevented clinical sequelae, resulting in increased survivability of mice. Since little is known as to how different AHLs modulate the immune response during infection, we treated mice with the above AHLs prior to lethalA. hydrophilainfection. When we compared results in such animals to those in controls, the treated animals exhibited a significantly reduced bacterial load in the blood and other mouse organs, as well as various levels of cytokines/chemokines. Importantly, neutrophil numbers were significantly elevated in the blood of C6-HSL-treated mice compared to those in animals given phosphate-buffered saline and then infected with the bacteria. These findings coincided with the fact that neutropenic animals were more susceptible toA. hydrophilainfection than normal mice. Our data suggested that neutrophils quickly cleared bacteria by either phagocytosis or possibly another mechanism(s) during infection. In a parallel study, we indeed showed that other predominant immune cells inflicted duringA. hydrophilainfections, such as murine macrophages, when they were pretreated with AHLs, rapidly phagocytosed bacteria, whereas untreated cells phagocytosed fewer bacteria. This study is the first to report that AHL pretreatment modulates the innate immune response in mice and enhances their survivability duringA. hydrophilainfection.

Optimization of Vibrio harveyi Luminometry Assay for Detecting Quorum Sensing Inhibitors

2005 ◽  
Vol 277-279 ◽  
pp. 19-22
Author(s):  
Yeon Hee Kim ◽  
Y. Kim ◽  
Sung Hoon Park ◽  
Jung Sun Kim
Keyword(s):  
Quorum Sensing ◽  
Vibrio Harveyi ◽  
Homoserine Lactone ◽  
Dependent Manner ◽  
Wild Type ◽  
Signal Molecule ◽  
Homoserine Lactones ◽  
Quorum Sensing Inhibitors ◽  
Chain Lengths ◽  
Dose Dependent

The luminometry assay using the wild-type Vibrio harveyi BB120 was evaluated as a possible detection method for quorum sensing inhibitors. The effects of the concentration of the quorum sensing signal molecule (AHL) as well as the cell density of the reporter strain and the different AHL analogues on luminescence expressed as relative light units (RLU) were examined. Inhibition of V. harveyi luminescence was observed in a dose dependent manner for all five AHL analogues. The RLU values exhibited linearity within the range of 2.9 x 102 ~ 3.2 x 105. Detection up to 102nM was possible for dodecanoyl-homoserine lactone and AHLs with alkyl chain lengths of C-8~C-14 were more active than the shorter chain-lengthed hexanoyl-homoserine lactones. Lipophilicity of the AHL seems to affect the sensitivity of the assay.

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