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Detection of quorum-sensing-related molecules in Vibrio scophthalmi.

García-Aljaro C, Eberl L, Riedel K, Blanch AR - BMC Microbiol. (2008)

Bottom Line: This observation was further supported by the decrease in the presence of these signal molecules after cloning and expression of lactonase AiiA from Bacillus cereus in the V. scophthalmi strains.One of the signal molecules was identified as N-(3-hydroxy dodecanoyl)-L-homoserine lactone.Analysis of the translated sequence revealed that the sequenced luxS gene carried the conserved domain, which is common to luxS sequences found in other species, and which is essential for LuxS enzymatic activity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology, University of Barcelona, Barcelona, Spain. cristina.garcia@cnm.es

ABSTRACT

Background: Cell-to-cell communication (also referred to as quorum sensing) based on N-acyl-homoserine lactones (AHLs) is a widespread response to environmental change in Gram-negative bacteria. AHLs seem to be highly variable, both in terms of the acyl chain length and in the chemical structure of the radicals. Another quorum sensing pathway, the autoinducer-2-based system, is present both in Gram-positive and Gram-negative bacteria. In this study the presence of signal molecules belonging to both quorum sensing signalling pathways was analysed in the marine symbiotic species Vibrio scophthalmi.

Results: Three AHL-like signal molecules were detected in V. scophthalmi supernatants with the Agrobacterium tumefaciens sensor assay. This observation was further supported by the decrease in the presence of these signal molecules after cloning and expression of lactonase AiiA from Bacillus cereus in the V. scophthalmi strains. One of the signal molecules was identified as N-(3-hydroxy dodecanoyl)-L-homoserine lactone. V. scophthalmi was also shown to carry a functional LuxS synthase. The coding sequence for a luxS-like gene was obtained showing a maximum similarity of 78% with Vibrio vulnificus. Analysis of the translated sequence revealed that the sequenced luxS gene carried the conserved domain, which is common to luxS sequences found in other species, and which is essential for LuxS enzymatic activity.

Conclusion: The data are consistent with the presence of quorum-sensing signal molecules from both AHL- and autoinducer 2-based quorum sensing systems in V. scophthalmi, which are homologous to others previously described in various Vibrio species. How this bacterium interacts with other bacteria and eukaryotic cells to compete ecologically with other intestinal bacteria present in the fish Scophthalmus maximus warrants further investigation.

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Detection of AHLs by thin layer chromatography (TLC) with the A. tumefaciens NTL4 (pZLR4) strain used as a biosensor (A) and AHL detection along the growth curve in mTSB medium (B). A) lane 1: C8-HSL standard (Fluka); lane 2: Vibrio scophthalmi A089 strain; lane 3: V. scophthalmi A102 strain; lane 4: Negative control, mTSB alone; lane 5: Negative control, no sample added; 6: C6-HSL standard (Fluka). B) Arrow indicates the beginning of the detection of the three signalling spots, which were detected at the same time from the mid-log phase.
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Figure 1: Detection of AHLs by thin layer chromatography (TLC) with the A. tumefaciens NTL4 (pZLR4) strain used as a biosensor (A) and AHL detection along the growth curve in mTSB medium (B). A) lane 1: C8-HSL standard (Fluka); lane 2: Vibrio scophthalmi A089 strain; lane 3: V. scophthalmi A102 strain; lane 4: Negative control, mTSB alone; lane 5: Negative control, no sample added; 6: C6-HSL standard (Fluka). B) Arrow indicates the beginning of the detection of the three signalling spots, which were detected at the same time from the mid-log phase.

Mentions: The V. scophthalmi strains A089 and A102 were grown overnight in different growth media (mLB, mTSB, mPW, and AB) and the supernatant was analysed for the presence of AHL-like molecules. Three different signal spots were detected in the TLC assay performed with the A. tumefaciens strain NTL4 (pZLR4) (Fig. 1a), which were not present in the medium alone used as negative control, suggesting the presence of three AHL-like molecules in the supernatant of V. scophthami. The retention factor (Rf) of the three AHL-like molecules was 0.62 (± 0.055), 0.46 (± 0.038) and 0.25 (± 0.018), from higher to lower Rf, respectively, as a result of three independent experiments. These three AHL-like molecules detected by the A. tumefaciens sensor strain were produced with any of the employed growth medium: mLB, mTSB, mPW, and AB (data not shown). Moreover, as shown on Fig. 1b, all three molecules were detected by TLC in the mid-exponential growth phase and maintained over the stationary phase.


Detection of quorum-sensing-related molecules in Vibrio scophthalmi.

García-Aljaro C, Eberl L, Riedel K, Blanch AR - BMC Microbiol. (2008)

Detection of AHLs by thin layer chromatography (TLC) with the A. tumefaciens NTL4 (pZLR4) strain used as a biosensor (A) and AHL detection along the growth curve in mTSB medium (B). A) lane 1: C8-HSL standard (Fluka); lane 2: Vibrio scophthalmi A089 strain; lane 3: V. scophthalmi A102 strain; lane 4: Negative control, mTSB alone; lane 5: Negative control, no sample added; 6: C6-HSL standard (Fluka). B) Arrow indicates the beginning of the detection of the three signalling spots, which were detected at the same time from the mid-log phase.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2527009&req=5

Figure 1: Detection of AHLs by thin layer chromatography (TLC) with the A. tumefaciens NTL4 (pZLR4) strain used as a biosensor (A) and AHL detection along the growth curve in mTSB medium (B). A) lane 1: C8-HSL standard (Fluka); lane 2: Vibrio scophthalmi A089 strain; lane 3: V. scophthalmi A102 strain; lane 4: Negative control, mTSB alone; lane 5: Negative control, no sample added; 6: C6-HSL standard (Fluka). B) Arrow indicates the beginning of the detection of the three signalling spots, which were detected at the same time from the mid-log phase.
Mentions: The V. scophthalmi strains A089 and A102 were grown overnight in different growth media (mLB, mTSB, mPW, and AB) and the supernatant was analysed for the presence of AHL-like molecules. Three different signal spots were detected in the TLC assay performed with the A. tumefaciens strain NTL4 (pZLR4) (Fig. 1a), which were not present in the medium alone used as negative control, suggesting the presence of three AHL-like molecules in the supernatant of V. scophthami. The retention factor (Rf) of the three AHL-like molecules was 0.62 (± 0.055), 0.46 (± 0.038) and 0.25 (± 0.018), from higher to lower Rf, respectively, as a result of three independent experiments. These three AHL-like molecules detected by the A. tumefaciens sensor strain were produced with any of the employed growth medium: mLB, mTSB, mPW, and AB (data not shown). Moreover, as shown on Fig. 1b, all three molecules were detected by TLC in the mid-exponential growth phase and maintained over the stationary phase.

Bottom Line: This observation was further supported by the decrease in the presence of these signal molecules after cloning and expression of lactonase AiiA from Bacillus cereus in the V. scophthalmi strains.One of the signal molecules was identified as N-(3-hydroxy dodecanoyl)-L-homoserine lactone.Analysis of the translated sequence revealed that the sequenced luxS gene carried the conserved domain, which is common to luxS sequences found in other species, and which is essential for LuxS enzymatic activity.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology, University of Barcelona, Barcelona, Spain. cristina.garcia@cnm.es

ABSTRACT

Background: Cell-to-cell communication (also referred to as quorum sensing) based on N-acyl-homoserine lactones (AHLs) is a widespread response to environmental change in Gram-negative bacteria. AHLs seem to be highly variable, both in terms of the acyl chain length and in the chemical structure of the radicals. Another quorum sensing pathway, the autoinducer-2-based system, is present both in Gram-positive and Gram-negative bacteria. In this study the presence of signal molecules belonging to both quorum sensing signalling pathways was analysed in the marine symbiotic species Vibrio scophthalmi.

Results: Three AHL-like signal molecules were detected in V. scophthalmi supernatants with the Agrobacterium tumefaciens sensor assay. This observation was further supported by the decrease in the presence of these signal molecules after cloning and expression of lactonase AiiA from Bacillus cereus in the V. scophthalmi strains. One of the signal molecules was identified as N-(3-hydroxy dodecanoyl)-L-homoserine lactone. V. scophthalmi was also shown to carry a functional LuxS synthase. The coding sequence for a luxS-like gene was obtained showing a maximum similarity of 78% with Vibrio vulnificus. Analysis of the translated sequence revealed that the sequenced luxS gene carried the conserved domain, which is common to luxS sequences found in other species, and which is essential for LuxS enzymatic activity.

Conclusion: The data are consistent with the presence of quorum-sensing signal molecules from both AHL- and autoinducer 2-based quorum sensing systems in V. scophthalmi, which are homologous to others previously described in various Vibrio species. How this bacterium interacts with other bacteria and eukaryotic cells to compete ecologically with other intestinal bacteria present in the fish Scophthalmus maximus warrants further investigation.

Show MeSH
Related in: MedlinePlus