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Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems.

Singh BR, Singh BN, Singh A, Khan W, Naqvi AH, Singh HB - Sci Rep (2015)

Bottom Line: Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR.Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors.The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling.

View Article: PubMed Central - PubMed

Affiliation: Centre of Excellence in Materials Science (Nanomaterials), Z.H. College of Engineering &Technology, Aligarh Muslim University, Aligarh-202002, India.

ABSTRACT
Quorum sensing (QS) is a chemical communication process that Pseudomonas aeruginosa uses to regulate virulence and biofilm formation. Disabling of QS is an emerging approach for combating its pathogenicity. Silver nanoparticles (AgNPs) have been widely applied as antimicrobial agents against human pathogenic bacteria and fungi, but not for the attenuation of bacterial QS. Here we mycofabricated AgNPs (mfAgNPs) using metabolites of soil fungus Rhizopus arrhizus BRS-07 and tested their effect on QS-regulated virulence and biofilm formation of P. aeruginosa. Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR. Treatment of mfAgNPs inhibited biofilm formation, production of several virulence factors (e.g. LasA protease, LasB elastrase, pyocyanin, pyoverdin, pyochelin, rhamnolipid, and alginate) and reduced AHLs production. Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors. The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling.

No MeSH data available.


Related in: MedlinePlus

Impact of mfAgNPs on the production of AHLs in PAO1.Quantification of C12-AHL and C4-AHL in mfAgNPs treated or untreated for 48 h by (A) HPLTC on silica gel 60 F254 TLC plates using a mobile phase of methanol-water-acetic acid (8:1.5:0.5) and by (B) ES-MS analysis. R, reference compound. C, untreated control. T, 25 μg/mL of mfAgNPs. Error bars indicate the SD of 3 measurements. **P < 0.01. *P < 0.05.
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f5: Impact of mfAgNPs on the production of AHLs in PAO1.Quantification of C12-AHL and C4-AHL in mfAgNPs treated or untreated for 48 h by (A) HPLTC on silica gel 60 F254 TLC plates using a mobile phase of methanol-water-acetic acid (8:1.5:0.5) and by (B) ES-MS analysis. R, reference compound. C, untreated control. T, 25 μg/mL of mfAgNPs. Error bars indicate the SD of 3 measurements. **P < 0.01. *P < 0.05.

Mentions: The lasI and rhlI genes are required for the synthesis of AHLs and the activation of LasR-RhlR regulon in P. aeruginosa. We were quite interested to probe if AHLs production would be inhibited in the PAO1 culture fluid after the treatment of mfAgNPs. Thus, PAO1 exposed to mfAgNPs was analyzed for the content of AHLs by HPTLC. Inhibition of C12-AHL and C4-AHL productions were observed, when PAO1 was exposed to 25 μg/mL of mfAgNPs (Fig. 5A). Fig. 5B shows the quantification of AHLs by electrospray mass spectroscopy (ES-MS). Production of AHLs was inhibited by mfAgNPs in a dose dependent manner (0–25 μg/mL): 5–76% reduction for C12-AHL and 2–69% inhibition for C4-AHL when compared to their untreated controls.


Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems.

Singh BR, Singh BN, Singh A, Khan W, Naqvi AH, Singh HB - Sci Rep (2015)

Impact of mfAgNPs on the production of AHLs in PAO1.Quantification of C12-AHL and C4-AHL in mfAgNPs treated or untreated for 48 h by (A) HPLTC on silica gel 60 F254 TLC plates using a mobile phase of methanol-water-acetic acid (8:1.5:0.5) and by (B) ES-MS analysis. R, reference compound. C, untreated control. T, 25 μg/mL of mfAgNPs. Error bars indicate the SD of 3 measurements. **P < 0.01. *P < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562228&req=5

f5: Impact of mfAgNPs on the production of AHLs in PAO1.Quantification of C12-AHL and C4-AHL in mfAgNPs treated or untreated for 48 h by (A) HPLTC on silica gel 60 F254 TLC plates using a mobile phase of methanol-water-acetic acid (8:1.5:0.5) and by (B) ES-MS analysis. R, reference compound. C, untreated control. T, 25 μg/mL of mfAgNPs. Error bars indicate the SD of 3 measurements. **P < 0.01. *P < 0.05.
Mentions: The lasI and rhlI genes are required for the synthesis of AHLs and the activation of LasR-RhlR regulon in P. aeruginosa. We were quite interested to probe if AHLs production would be inhibited in the PAO1 culture fluid after the treatment of mfAgNPs. Thus, PAO1 exposed to mfAgNPs was analyzed for the content of AHLs by HPTLC. Inhibition of C12-AHL and C4-AHL productions were observed, when PAO1 was exposed to 25 μg/mL of mfAgNPs (Fig. 5A). Fig. 5B shows the quantification of AHLs by electrospray mass spectroscopy (ES-MS). Production of AHLs was inhibited by mfAgNPs in a dose dependent manner (0–25 μg/mL): 5–76% reduction for C12-AHL and 2–69% inhibition for C4-AHL when compared to their untreated controls.

Bottom Line: Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR.Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors.The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling.

View Article: PubMed Central - PubMed

Affiliation: Centre of Excellence in Materials Science (Nanomaterials), Z.H. College of Engineering &Technology, Aligarh Muslim University, Aligarh-202002, India.

ABSTRACT
Quorum sensing (QS) is a chemical communication process that Pseudomonas aeruginosa uses to regulate virulence and biofilm formation. Disabling of QS is an emerging approach for combating its pathogenicity. Silver nanoparticles (AgNPs) have been widely applied as antimicrobial agents against human pathogenic bacteria and fungi, but not for the attenuation of bacterial QS. Here we mycofabricated AgNPs (mfAgNPs) using metabolites of soil fungus Rhizopus arrhizus BRS-07 and tested their effect on QS-regulated virulence and biofilm formation of P. aeruginosa. Transcriptional studies demonstrated that mfAgNPs reduced the levels of LasIR-RhlIR. Treatment of mfAgNPs inhibited biofilm formation, production of several virulence factors (e.g. LasA protease, LasB elastrase, pyocyanin, pyoverdin, pyochelin, rhamnolipid, and alginate) and reduced AHLs production. Further genes quantification analyses revealed that mfAgNPs significantly down-regulated QS-regulated genes, specifically those encoded to the secretion of virulence factors. The results clearly indicated the anti-virulence property of mfAgNPs by inhibiting P. aeruginosa QS signaling.

No MeSH data available.


Related in: MedlinePlus