Production of acylated homoserine lactones byAeromonasandPseudomonasstrains isolated from municipal activated sludge

2005 ◽  
Vol 51 (11) ◽  
pp. 924-933 ◽  
Author(s):  
Fernando Morgan-Sagastume ◽  
Nico Boon ◽  
Sofie Dobbelaere ◽  
Tom Defoirdt ◽  
Willy Verstraete
Keyword(s):  
Activated Sludge ◽  
Homoserine Lactone ◽  
Homoserine Lactones ◽  
Pseudomonas Spp ◽  
Signal Production ◽  
Reporter Strains ◽  
Overlay Technique ◽  
Different Strains ◽  
Acylated Homoserine Lactones ◽  
Layer Chromatography

Up to now, the production and role of N-acyl homoserine lactones (AHLs) in activated sludge have been poorly understood. In this study, cross-feeding assays with the reporter strains Agrobacterium tumefaciens NTL4 and Chromobacterium violaceum CV026 were used to investigate AHL signal production by municipal activated sludge samples. AHL signal production was consistently detected from municipal activated sludge when different samples were incubated on nutrient media. From one municipal activated sludge sample, 10 strains producing AHL-like auto inducers were isolated by an overlay technique. 16S rDNA-based phylogenetic analysis showed that eight of the isolates belonged to Aeromonas spp. and two to Pseudomonas spp. Box-PCR indicated that six of these Aeromonas isolates were different strains and the two Pseudomonas strains were identical. The production of AHL or AHL-like compounds by these strains was confirmed by thin layer chromatography and biosensor overlays. The six different Aeromonas strains were found to produce the same set of AHLs, including N-hexanoyl-L-homoserine lactone. These results may indicate the possible presence of AHLs in municipal activated sludge. The potential roles of AHL in this eco system are briefly discussed.Key words: municipal activated sludge, acylated homoserine lactones, Aeromonas spp., bioaggregates, Pseudomonas spp., AHL biosensors.

scholarly journals Production of Acylated Homoserine Lactones by Psychrotrophic Members of the Enterobacteriaceae Isolated from Foods

1999 ◽  
Vol 65 (8) ◽  
pp. 3458-3463 ◽  
Author(s):  
Lone Gram ◽  
Allan Beck Christensen ◽  
Lars Ravn ◽  
Søren Molin ◽  
Michael Givskov
Keyword(s):  
Gene Regulation ◽  
Homoserine Lactone ◽  
Food Preservation ◽  
Signal Molecules ◽  
Homoserine Lactones ◽  
Smoked Salmon ◽  
Cell Densities ◽  
Acylated Homoserine Lactones ◽  
And Storage ◽  
Layer Chromatography

ABSTRACT Bacteria are able to communicate and gene regulation can be mediated through the production of acylated homoserine lactone (AHL) signal molecules. These signals play important roles in several pathogenic and symbiotic bacteria. The following study was undertaken to investigate whether AHLs are produced by bacteria found in food at temperatures and NaCl conditions commercially used for food preservation and storage. A minimum of 116 of 154 psychrotrophicEnterobacteriaceae strains isolated from cold-smoked salmon or vacuum-packed chilled meat produced AHLs. Analysis by thin-layer chromatography indicated that N-3-oxo-hexanoyl homoserine lactone was the major AHL of several of the strains isolated from cold-smoked salmon and meat. AHL-positive strains cultured at 5°C in medium supplemented with 4% NaCl produced detectable amounts of AHL(s) at cell densities of 106 CFU/ml. AHLs were detected in cold-smoked salmon inoculated with strains ofEnterobacteriaceae stored at 5°C under an N2atmosphere when mean cell densities increased to 106 CFU/g and above. Similarly, AHLs were detected in uninoculated samples of commercially produced cold-smoked salmon when the level of indigenousEnterobacteriaceae reached 106 CFU/g. This level of Enterobacteriaceae is often found in lightly preserved foods, and AHL-mediated gene regulation may play a role in bacteria associated with food spoilage or food toxicity.

scholarly journals Reaction of Acylated Homoserine Lactone Bacterial Signaling Molecules with Oxidized Halogen Antimicrobials

2001 ◽  
Vol 67 (7) ◽  
pp. 3174-3179 ◽  
Author(s):  
S. A. Borchardt ◽  
E. J. Allain ◽  
J. J. Michels ◽  
G. W. Stearns ◽  
R. F. Kelly ◽  
...  
Keyword(s):  
Cell Signaling ◽  
Marine Alga ◽  
Defense Mechanism ◽  
Microbial Control ◽  
Homoserine Lactone ◽  
Signaling Molecules ◽  
Chromobacterium Violaceum ◽  
Homoserine Lactones ◽  
Acylated Homoserine Lactone ◽  
Acylated Homoserine Lactones

ABSTRACT Oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. Recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in Pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. This study was conducted to investigate the potential for oxidized halogens to react with acylated homoserine lactone-based signaling molecules. Acylated homoserine lactones containing a 3-oxo group were found to rapidly react with oxidized halogens, while acylated homoserine lactones lacking the 3-oxo functionality did not react. The Chromobacterium violaceum CV026 bioassay was used to determine the effects of such reactions on acylated homoserine lactone activity. The results demonstrated that 3-oxo acyl homoserine lactone activity was rapidly lost upon exposure to oxidized halogens; however, acylated homoserine lactones lacking the 3-oxo group retained activity. Experiments with the marine alga Laminaria digitata demonstrated that natural haloperoxidase systems are capable of mediating the deactivation of acylated homoserine lactones. This may illustrate a natural defense mechanism to prevent biofouling on the surface of this marine alga. The Chromobacterium violaceum activity assay illustrates that reactions between 3-oxo acylated homoserine lactone molecules and oxidized halogens do occur despite the presence of biofilm components at much greater concentrations. This work suggests that oxidized halogens may control biofilm not only via a cidal mechanism, but also by possibly interfering with 3-oxo acylated homoserine lactone-based cell signaling.

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 ◽  
...  
Keyword(s):  
Bacterial Communities ◽  
Bacterial Colonization ◽  
Homoserine Lactone ◽  
Marine Sponges ◽  
Acyl Homoserine Lactone ◽  
Homoserine Lactones ◽  
Acyl Homoserine Lactones ◽  
Signal Production ◽  
First Time ◽  
Quorum Sensing Signals

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.

scholarly journals Nonbioluminescent Strains of Photobacterium phosphoreum Produce the Cell-to-Cell Communication Signal N-(3-Hydroxyoctanoyl)homoserine Lactone

2005 ◽  
Vol 71 (4) ◽  
pp. 2113-2120 ◽  
Author(s):  
L. R. Flodgaard ◽  
P. Dalgaard ◽  
J. B. Andersen ◽  
K. F. Nielsen ◽  
M. Givskov ◽  
...  
Keyword(s):  
High Performance ◽  
High Resolution Mass Spectrometry ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Photobacterium Phosphoreum ◽  
Relative Mobility ◽  
Homoserine Lactones ◽  
Communication Signal ◽  
Culture Supernatants ◽  
Acylated Homoserine Lactones

ABSTRACT Bioluminescence is a common phenotype in marine bacteria, such as Vibrio and Photobacterium species, and can be quorum regulated by N-acylated homoserine lactones (AHLs). We extracted a molecule that induced a bacterial AHL monitor (Agrobacterium tumefaciens NT1 [pZLR4]) from packed cod fillets, which spoil due to growth of Photobacterium phosphoreum. Interestingly, AHLs were produced by 13 nonbioluminescent strains of P. phosphoreum isolated from the product. Of 177 strains of P. phosphoreum (including 18 isolates from this study), none of 74 bioluminescent strains elicited a reaction in the AHL monitor, whereas 48 of 103 nonbioluminescent strains did produce AHLs. AHLs were also detected in Aeromonas spp., but not in Shewanella strains. Thin-layer chromatographic profiles of cod extracts and P. phosphoreum culture supernatants identified a molecule similar in relative mobility (Rf value) and shape to N-(3-hydroxyoctanoyl)homoserine lactone, and the presence of this molecule in culture supernatants from a nonbioluminescent strain of P. phosphoreum was confirmed by high-performance liquid chromatography-positive electrospray high-resolution mass spectrometry. Bioluminescence (in a non-AHL-producing strain of P. phosphoreum) was strongly up-regulated during growth, whereas AHL production in a nonbioluminescent strain of P. phosphoreum appeared constitutive. AHLs apparently did not influence bioluminescence, as the addition of neither synthetic AHLs nor supernatants delayed or reduced this phenotype in luminescent strains of P. phosphoreum. The phenotypes of nonbioluminescent P. phosphoreum strains regulated by AHLs remains to be elucidated.

scholarly journals Long- and Short-Chain Plant-Produced Bacterial N-Acyl-Homoserine Lactones Become Components of Phyllosphere, Rhizosphere, and Soil

2006 ◽  
Vol 19 (3) ◽  
pp. 227-239 ◽  
Author(s):  
Russell A. Scott ◽  
Jason Weil ◽  
Phuong T. Le ◽  
Paul Williams ◽  
Rupert G. Fray ◽  
...  
Keyword(s):  
Leaf Tissue ◽  
Homoserine Lactone ◽  
Wild Type ◽  
Fresh Weight ◽  
Liquid Chromatograph ◽  
Homoserine Lactones ◽  
Transgenic Lines ◽  
Axenic Conditions ◽  
Root Tissues ◽  
Layer Chromatography

Two N-acyl-homoserine lactone (acyl-HSL) synthase genes, lasI from Pseudomonas aeruginosa and yenI from Yersinia enterocolitica, were introduced into tobacco, individually and in combination. Liquid chromatograph-tandem mass spectrometry and thin-layer chromatography confirmed products of lasI and yenI activity in single and cotransformants. Cotransformants expressing plastid-localized LasI and YenI synthases produced the major acyl-HSLs for each synthase in all tissues tested. Total acyl-HSL signals accumulated in leaf tissue up to 3 pmol/mg of fresh weight, half as much in stem tissue, and approximately 10-fold less in root tissues. Acyl-HSLs were present in aqueous leaf washes from greenhouse-grown transgenic plants. Transgenic lines grown for 14 days under axenic conditions produced detectable levels of acyl-HSLs in root exudates. Ethyl acetate extractions of rhizosphere and nonrhizosphere soil from transgenically grown plants contained active acyl-HSLs, whereas plant-free soil or rhizosphere and nonrhizosphere soil from wild-type plants lacked detectable amounts of acyl-HSLs. This work shows that bioactive acyl-HSLs are exuded from leaves and roots and accumulate in the phytosphere of plants engineered to produce acyl-HSLs. These data further suggest that plants that are bioengineered to synthesize acyl-HSLs can foster beneficial plant-bacteria communications or deter deleterious interactions. Therefore, it is feasible to use bioengineered plants to supplement soils with specific acyl-HSLs to modulate bacterial phenotypes and plant-associated bacterial community structures.

scholarly journals Streptomycin Inhibits Quorum Sensing in Acinetobacter baumannii

2013 ◽  
Vol 57 (4) ◽  
pp. 1926-1929 ◽  
Author(s):  
Sunil D. Saroj ◽  
Philip N. Rather
Keyword(s):  
Quorum Sensing ◽  
Thin Layer ◽  
Acinetobacter Baumannii ◽  
Direct Analysis ◽  
Homoserine Lactone ◽  
Acyl Homoserine Lactone ◽  
Content Type ◽  
Signal Production ◽  
Subinhibitory Concentrations ◽  
Layer Chromatography

ABSTRACTStreptomycin at subinhibitory concentrations was found to inhibit quorum sensing inAcinetobacter baumannii. Conditioned medium prepared by growth ofA. baumanniiin the presence of subinhibitory concentrations of streptomycin exhibited reduced activation of two quorum-sensing-regulated genes,abaI, encoding an autoinducer synthase, and A1S_0112. The reduced expression of AbaI resulted in greatly decreased levels of 3-OH-C12-HSL as confirmed by direct analysis using thin-layer chromatography. The effect on acyl-homoserine lactone (AHL) signal production was specific to streptomycin, as gentamicin and myomycin had no significant effect at subinhibitory levels.

scholarly journals Presence of Acylated Homoserine Lactones (AHLs) and AHL-Producing Bacteria in Meat and Potential Role of AHL in Spoilage of Meat

2004 ◽  
Vol 70 (7) ◽  
pp. 4293-4302 ◽  
Author(s):  
Jesper Bartholin Bruhn ◽  
Allan Beck Christensen ◽  
Lars Ravn Flodgaard ◽  
Kristian Fog Nielsen ◽  
Thomas Ostenfeld Larsen ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Homoserine Lactone ◽  
Wild Type ◽  
Homoserine Lactones ◽  
Serratia Proteamaculans ◽  
Pure Cultures ◽  
Meat Samples ◽  
Protease Secretion ◽  
Acylated Homoserine Lactones

ABSTRACT Quorum-sensing (QS) signals (N-acyl homoserine lactones [AHLs]) were extracted and detected from five commercially produced vacuum-packed meat samples. Ninety-six AHL-producing bacteria were isolated, and 92 were identified as Enterobacteriaceae. Hafnia alvei was the most commonly identified AHL-producing bacterium. Thin-layer chromatographic profiles of supernatants from six H. alvei isolates and of extracts from spoiling meat revealed that the major AHL species had an Rf value and shape similar to N-3-oxo-hexanoyl homoserine lactone (OHHL). Liquid chromatography-mass spectrometry (MS) (high-resolution MS) analysis confirmed the presence of OHHL in pure cultures of H. alvei. Vacuum-packed meat spoiled at the same rate when inoculated with the H. alvei wild type compared to a corresponding AHL-lacking mutant. Addition of specific QS inhibitors to the AHL-producing H. alvei inoculated in meat or to naturally contaminated meat did not influence the spoilage of vacuum-packed meat. An extracellular protein of approximately 20 kDa produced by the H. alvei wild-type was not produced by the AHL-negative mutant but was restored in the mutant when complemented by OHHL, thus indicating that AHLs do have a regulatory role in H. alvei. Coinoculation of H. alvei wild-type with an AHL-deficient Serratia proteamaculans B5a, in which protease secretion is QS regulated, caused spoilage of liquid milk. By contrast, coinoculation of AHL-negative strains of H. alvei and S. proteamaculans B5a did not cause spoilage. In conclusion, AHL and AHL-producing bacteria are present in vacuum-packed meat during storage and spoilage, but AHL does not appear to influence the spoilage of this particular type of conserved meat. Our data indicate that AHL-producing H. alvei may induce food quality-relevant phenotypes in other bacterial species in the same environment. H. alvei may thus influence spoilage of food products in which Enterobacteriaceae participate in the spoilage process.

scholarly journals A Marine Mesorhizobium sp. Produces Structurally Novel Long-Chain N-Acyl-l-Homoserine Lactones

2007 ◽  
Vol 73 (11) ◽  
pp. 3587-3594 ◽  
Author(s):  
Anja Krick ◽  
Stefan Kehraus ◽  
Leo Eberl ◽  
Kathrin Riedel ◽  
Heidrun Anke ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Solid Phase ◽  
Homoserine Lactone ◽  
Signal Molecules ◽  
Cytotoxic Activities ◽  
Rrna Gene ◽  
Liquid Chromatography Mass Spectrometry ◽  
Homoserine Lactones ◽  
Chain Lengths ◽  
Acylated Homoserine Lactones

ABSTRACT Our study focused on a Mesorhizobium sp. that is phylogenetically affiliated by 16S rRNA gene sequence to other marine and saline bacteria of this genus. Liquid chromatography-mass spectrometry investigations of the extract obtained from solid-phase extraction of cultures of this bacterium indicated the presence of several N-acyl homoserine lactones (AHLs), with chain lengths of C10 to C16. Chromatographic separation of the active bacterial extract yielded extraordinarily large amounts of two unprecedented acylated homoserine lactones, 5-cis-3-oxo-C12-homoserine lactone (5-cis-3-oxo-C12-HSL) (compound 1) and 5-cis-C12-HSL (compound 2). Quorum-sensing activity of compounds 1 and 2 was shown in two different biosensor systems [Escherichia coli MT102(pSB403) and Pseudomonas putida F117(pKR-C12)]. Furthermore, it was shown that both compounds can restore protease and pyoverdin production of an AHL-deficient Pseudomonas aeruginosa PAO1 lasI rhlI double mutant, suggesting that these signal molecules maybe used for intergenus signaling. In conclusion, these data indicate that the quorum-sensing activity of compounds 1 and 2 is modulated by the chain length and functional groups of the acyl moiety. Additionally, compound 1 showed antibacterial and cytotoxic activities.

Hybrids of acylated homoserine lactone and nitric oxide donors as inhibitors of quorum sensing and virulence factors in Pseudomonas aeruginosa

2015 ◽  
Vol 13 (38) ◽  
pp. 9850-9861 ◽  
Author(s):  
Samuel K. Kutty ◽  
Nicolas Barraud ◽  
Kitty K. K. Ho ◽  
George M. Iskander ◽  
Renate Griffith ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Homoserine Lactone ◽  
Nitric Oxide Donors ◽  
Quorum Sensing Inhibition ◽  
Homoserine Lactones ◽  
Nitric Oxide Release ◽  
Acylated Homoserine Lactones

This paper discusses conversion of agonist acylated homoserine lactones (AHL) to antagonist AHLs with dual properties of quorum sensing inhibition and nitric oxide release.

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