scholarly journals Evidence for Acyl Homoserine Lactone Signal Production in Bacteria Associated with Marine Sponges

2004 ◽  
Vol 70 (7) ◽  
pp. 4387-4389 ◽  
Author(s):  
Michael W. Taylor ◽  
Peter J. Schupp ◽  
Harriet J. Baillie ◽  
Timothy S. Charlton ◽  
Rocky de Nys ◽  
...  

ABSTRACT We report for the first time the production of acyl homoserine lactones (AHLs) by bacteria associated with marine sponges. Given the involvement of AHLs in bacterial colonization of many higher organisms, we speculate that such quorum sensing signals could play a part in interactions between sponges and the dense bacterial communities living within them.

2000 ◽  
Vol 182 (24) ◽  
pp. 6921-6926 ◽  
Author(s):  
Jared R. Leadbetter ◽  
E. P. Greenberg

ABSTRACT Acyl-homoserine lactones (acyl-HSLs) serve as dedicated cell-to-cell signaling molecules in many species of the classProteobacteria. We have addressed the question of whether these compounds can be degraded biologically. A motile, rod-shaped bacterium was isolated from soil based upon its ability to utilizeN-(3-oxohexanoyl)-l-homoserine lactone as the sole source of energy and nitrogen. The bacterium was classified as a strain of Variovorax paradoxus. TheV. paradoxus isolate was capable of growth on all of the acyl-HSLs tested. The molar growth yields correlated with the length of the acyl group. HSL, a product of acyl-HSL metabolism, was used as a nitrogen source, but not as an energy source. Cleavage and partial mineralization of the HSL ring were demonstrated by using radiolabeled substrate. This study indicates that some strains of V. paradoxus degrade and grow on acyl-HSL signals as the sole energy and nitrogen sources. This study provides clues about the metabolic pathway of acyl-HSL degradation by V. paradoxus.


2020 ◽  
Vol 8 (19) ◽  
pp. 4228-4236
Author(s):  
Sahana Vasudevan ◽  
Parthasarathy Srinivasan ◽  
John Bosco Balaguru Rayappan ◽  
Adline Princy Solomon

We report a PL biosensor using cysteamine functionalized ZnO nanoparticles for the detection of quorum sensing signals (N-acyl homoserine lactones).


2008 ◽  
Vol 75 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Ryan W. Shepherd ◽  
Steven E. Lindow

ABSTRACT Plant aerial surfaces comprise a complex habitat for microorganisms, and many plant-associated bacteria, such as the pathogen Pseudomonas syringae, exhibit density-dependent survival on leaves by utilizing quorum sensing (QS). QS is often mediated by diffusible signals called N-acyl-homoserine lactones (AHLs), and P. syringae utilizes N-3-oxo-hexanoyl-dl-homoserine lactone (3OC6HSL) to control traits influencing epiphytic fitness and virulence. The P. syringae pathovar syringae B728a genome sequence revealed two putative AHL acylases, termed HacA (Psyr_1971) and HacB (Psyr_4858), which are N-terminal nucleophile hydrolases that inactivate AHLs by cleaving their amide bonds. HacA is a secreted AHL acylase that degrades only long-chain (C ≥ 8) AHLs, while HacB is not secreted and degrades all tested AHLs. Targeted disruptions of hacA, hacB, and hacA and hacB together do not alter endogenous 3OC6HSL levels under the tested conditions. Surprisingly, targeted disruptions of hacA alone and hacA and hacB together confer complementable phenotypes that are very similar to autoaggregative phenotypes seen in other species. While AHL acylases might enable P. syringae B728a to degrade signals of competing species and block expression of their QS-dependent traits, these enzymes also play fundamental roles in biofilm formation.


2002 ◽  
Vol 184 (23) ◽  
pp. 6515-6521 ◽  
Author(s):  
Amy L. Schaefer ◽  
Terumi A. Taylor ◽  
J. Thomas Beatty ◽  
E. P. Greenberg

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.


2012 ◽  
Vol 25 (5) ◽  
pp. 677-683 ◽  
Author(s):  
Fang Liu ◽  
Ziriu Bian ◽  
Zhenhua Jia ◽  
Qian Zhao ◽  
Shuishan Song

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.


2007 ◽  
Vol 73 (11) ◽  
pp. 3724-3727 ◽  
Author(s):  
Kristen M. DeAngelis ◽  
Mary K. Firestone ◽  
Steven E. Lindow

ABSTRACT To investigate quorum sensing in rhizosphere soil, a whole-cell biosensor, Agrobacterium tumefaciens(pAHL-Ice), was constructed. The biosensor responded to all N-acyl homoserine lactones (AHLs) tested, except C4 homoserine lactone, with a minimum detection limit of 10−12 M, as well as to both exogenously added AHLs and AHL-producing bacterial strains in soil. This highly sensitive biosensor reveals for the first time the increased AHL availability in intact rhizosphere microbial communities compared to that in bulk soil.


RSC Advances ◽  
2018 ◽  
Vol 8 (54) ◽  
pp. 30783-30793 ◽  
Author(s):  
Xiujie Wang ◽  
Weiqi Wang ◽  
Yun Li ◽  
Jing Zhang ◽  
Yang Zhang ◽  
...  

In the present study, the heterotrophic nitrification–aerobic denitrification strain,Acinetobactersp. JQ1004, was treated with three typicalN-acyl-homoserine lactone (AHL) molecules (C6-HSL, C8-HSL, and 3-oxo-C10-HSL) during the nitrogen removal process.


2007 ◽  
Vol 189 (14) ◽  
pp. 5034-5040 ◽  
Author(s):  
Breck A. Duerkop ◽  
Ricky L. Ulrich ◽  
E. Peter Greenberg

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.


2013 ◽  
Vol 81 (5) ◽  
pp. 1471-1478 ◽  
Author(s):  
Charlotte Majerczyk ◽  
Loren Kinman ◽  
Tony Han ◽  
Richard Bunt ◽  
E. Peter Greenberg

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.


2021 ◽  
Author(s):  
Jing Lu ◽  
Ziqin Li ◽  
Hui Yang ◽  
Qiang Zhang ◽  
wenting Jia

Abstract The effect of N-acyl-homoserine lactone (AHL)-based quorum sensing (QS) on biogenic amine (BA) formation by Pantoea agglomerans was studied. Agrobacterium tumefaciens A136 and KYC55-based bioassays confirmed AHLs production by Pantoea agglomerans. The production ability of AHLs was quantified on the basis of β-galactosidase activity. The influence of temperature (10°C and 20°C) and pH (5.5 and 6.5) on β-galactosidase activity and BAs production by Pantoea agglomerans was determined. Acidification of the environment adversely affected the growth and β-galactosidase activity of Pantoea agglomerans, and AHLs production and BAs accumulation by Pantoea agglomerans was inhibited at low temperature. A significant correlation between β-galactosidase activity and BAs (putrescine, histamine, putrescine and tryptamine) was identified (P < 0.01). Based on the results of this study, the AHL-based QS system influences the concentrations and types of BAs produced by Pantoea agglomerans.


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