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Strain identification and quorum sensing inhibition characterization of marine-derived Rhizobium sp. NAO1

View Article: PubMed Central - PubMed

ABSTRACT

A novel strategy for combating pathogens is through the ongoing development and use of anti-quorum sensing (QS) treatments such as therapeutic bacteria or their anti-QS substances. Relatively little is known about the bacteria that inhabit the open ocean and of their potential anti-pathogenic attributes; thus, in an initiative to identify these types of therapeutic bacteria, planktonic microbes from the North Atlantic Ocean were collected, isolated, cultured and screened for anti-QS activity. Screening analysis identified one such strain, Rhizobium sp. NAO1. Extracts of Rhizobium sp. NAO1 were identified via ultra-performance liquid chromatography (UPLC) analysis. They were shown to contain N-acyl homoserine lactone (AHL)-based QS analogues (in particular, the N-butyryl homoserine lactone (C4-AHL) analogue) and could disrupt biofilm formation by Pseudomonas aeruginosa PAO1. QS inhibition was confirmed using confocal scanning laser microscopy and growth curves, and it was shown to occur in a dose-dependent manner without affecting bacterial growth. Secondary metabolites of Rhizobium sp. NAO1 inhibited PAO1 pathogenicity by downregulating AHL-mediated virulence factors such as elastase activity and siderophore production. Furthermore, as a result of biofilm structure damage, the secondary metabolite products of Rhizobium sp. NAO1 significantly increased the sensitivity of PAO1 to aminoglycoside antibiotics. Our results demonstrated that Rhizobium sp. strain NAO1 has the ability to disrupt P. aeruginosa PAO1 biofilm architecture, in addition to attenuating P. aeruginosa PAO1 virulence factor production and pathogenicity. Therefore, the newly identified ocean-derived Rhizobium sp. NAO1 has the potential to serve as a QS inhibitor and may be a new microbial resource for drug development.

No MeSH data available.


Effect of QSI on P. aeruginosa growth. Bacteria were grown in LB media with (red line) and without (blue line) QSI supernatant (5%). The flow cytometry results show the count of the bacterial cells (inset picture).
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RSOS170025F6: Effect of QSI on P. aeruginosa growth. Bacteria were grown in LB media with (red line) and without (blue line) QSI supernatant (5%). The flow cytometry results show the count of the bacterial cells (inset picture).

Mentions: The effect of the QSI supernatant on P. aeruginosa growth is shown in figureĀ 6. The growth curves for untreated and treated P. aeruginosa PAO1 were almost identical, indicating that the addition of QSI supernatant did not affect growth of P. aeruginosa PAO1.Figure 6.


Strain identification and quorum sensing inhibition characterization of marine-derived Rhizobium sp. NAO1
Effect of QSI on P. aeruginosa growth. Bacteria were grown in LB media with (red line) and without (blue line) QSI supernatant (5%). The flow cytometry results show the count of the bacterial cells (inset picture).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383856&req=5

RSOS170025F6: Effect of QSI on P. aeruginosa growth. Bacteria were grown in LB media with (red line) and without (blue line) QSI supernatant (5%). The flow cytometry results show the count of the bacterial cells (inset picture).
Mentions: The effect of the QSI supernatant on P. aeruginosa growth is shown in figureĀ 6. The growth curves for untreated and treated P. aeruginosa PAO1 were almost identical, indicating that the addition of QSI supernatant did not affect growth of P. aeruginosa PAO1.Figure 6.

View Article: PubMed Central - PubMed

ABSTRACT

A novel strategy for combating pathogens is through the ongoing development and use of anti-quorum sensing (QS) treatments such as therapeutic bacteria or their anti-QS substances. Relatively little is known about the bacteria that inhabit the open ocean and of their potential anti-pathogenic attributes; thus, in an initiative to identify these types of therapeutic bacteria, planktonic microbes from the North Atlantic Ocean were collected, isolated, cultured and screened for anti-QS activity. Screening analysis identified one such strain, Rhizobium sp. NAO1. Extracts of Rhizobium sp. NAO1 were identified via ultra-performance liquid chromatography (UPLC) analysis. They were shown to contain N-acyl homoserine lactone (AHL)-based QS analogues (in particular, the N-butyryl homoserine lactone (C4-AHL) analogue) and could disrupt biofilm formation by Pseudomonas aeruginosa PAO1. QS inhibition was confirmed using confocal scanning laser microscopy and growth curves, and it was shown to occur in a dose-dependent manner without affecting bacterial growth. Secondary metabolites of Rhizobium sp. NAO1 inhibited PAO1 pathogenicity by downregulating AHL-mediated virulence factors such as elastase activity and siderophore production. Furthermore, as a result of biofilm structure damage, the secondary metabolite products of Rhizobium sp. NAO1 significantly increased the sensitivity of PAO1 to aminoglycoside antibiotics. Our results demonstrated that Rhizobium sp. strain NAO1 has the ability to disrupt P. aeruginosa PAO1 biofilm architecture, in addition to attenuating P. aeruginosa PAO1 virulence factor production and pathogenicity. Therefore, the newly identified ocean-derived Rhizobium sp. NAO1 has the potential to serve as a QS inhibitor and may be a new microbial resource for drug development.

No MeSH data available.