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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 LuxS activity in the supernatant of the V. scophthalmi A089 strain by a bioluminescence assay using the V. harveyi reporter strain BB170. Bars, relative light units produced by stimulation of the V. harveyi BB170 reporter strain after addition of supernatant from V. scophthalmi A089, taken at different time points; squares, growth of V. scophthalmi as measured by OD at 600 nm.
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Figure 4: Detection of LuxS activity in the supernatant of the V. scophthalmi A089 strain by a bioluminescence assay using the V. harveyi reporter strain BB170. Bars, relative light units produced by stimulation of the V. harveyi BB170 reporter strain after addition of supernatant from V. scophthalmi A089, taken at different time points; squares, growth of V. scophthalmi as measured by OD at 600 nm.

Mentions: The presence of LuxS activity in the supernatants from the V. scophthalmi A089 strain was assessed by using the V. harveyi reporter strain BB170 in a bioluminescence assay. Two negative controls were included, consisting of the incubation medium alone, and the medium with the sensor strain. Although we tested two different culture media, mTSB and the mPW, the former was discarded due to the fact that some of the components of the mTSB induced the sensor strain producing a false positive reaction. As shown in Fig. 4, the maximum induction level for the reporter strain was obtained in those supernatants from V. scophthalmi A089 grown in mPW medium, which corresponded to the late logarithmic phase. Here, we recorded a maximum induction value of 35% with respect to the positive control used in this assay, V. harveyi BB120.


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

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

Detection of LuxS activity in the supernatant of the V. scophthalmi A089 strain by a bioluminescence assay using the V. harveyi reporter strain BB170. Bars, relative light units produced by stimulation of the V. harveyi BB170 reporter strain after addition of supernatant from V. scophthalmi A089, taken at different time points; squares, growth of V. scophthalmi as measured by OD at 600 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 4: Detection of LuxS activity in the supernatant of the V. scophthalmi A089 strain by a bioluminescence assay using the V. harveyi reporter strain BB170. Bars, relative light units produced by stimulation of the V. harveyi BB170 reporter strain after addition of supernatant from V. scophthalmi A089, taken at different time points; squares, growth of V. scophthalmi as measured by OD at 600 nm.
Mentions: The presence of LuxS activity in the supernatants from the V. scophthalmi A089 strain was assessed by using the V. harveyi reporter strain BB170 in a bioluminescence assay. Two negative controls were included, consisting of the incubation medium alone, and the medium with the sensor strain. Although we tested two different culture media, mTSB and the mPW, the former was discarded due to the fact that some of the components of the mTSB induced the sensor strain producing a false positive reaction. As shown in Fig. 4, the maximum induction level for the reporter strain was obtained in those supernatants from V. scophthalmi A089 grown in mPW medium, which corresponded to the late logarithmic phase. Here, we recorded a maximum induction value of 35% with respect to the positive control used in this assay, V. harveyi BB120.

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