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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

Effect of mfAgNPs on the expression of QS-controlled genes of PAO1.(A) The expression of genes namely lasA, lasB, phzA1, and rhlA, lasI, lasR, rhlI, rhlR, fabH2, and proC (housekeeping gene) was assessed in mfAgNPs treated or untreated control cDNA by RT-qPCR. The relative magnitude of gene expression level was defined as the copy number of cDNA of each gene in the planktonic cells normalized by the copy number of cDNA of the corresponding gene in planktonic cells without mfAgNPs. Error bars indicate the SD of 3 measurements. ***P < 0.001 Vs control. **P < 0.01 Vs the control. *P < 0.05 Vs control. The same volume of H2O was added to the control treatments.
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f4: Effect of mfAgNPs on the expression of QS-controlled genes of PAO1.(A) The expression of genes namely lasA, lasB, phzA1, and rhlA, lasI, lasR, rhlI, rhlR, fabH2, and proC (housekeeping gene) was assessed in mfAgNPs treated or untreated control cDNA by RT-qPCR. The relative magnitude of gene expression level was defined as the copy number of cDNA of each gene in the planktonic cells normalized by the copy number of cDNA of the corresponding gene in planktonic cells without mfAgNPs. Error bars indicate the SD of 3 measurements. ***P < 0.001 Vs control. **P < 0.01 Vs the control. *P < 0.05 Vs control. The same volume of H2O was added to the control treatments.

Mentions: To further explore anti-QS potential of mfAgNPs, expression of QS-regulated genes encoding virulence factors of P. aeruginosa PAO1 was studied. The expression of genes such as lasA, lasB, phzA1, and rhlA of PAO1 planktonic cells was analyzed to identify the genes targeted by mfAgNPs and to investigate the molecular mechanism that reduces virulence when mfAgNPs are supplemented. RT-qPCR analysis was to compare the gene expression between PAO1 cells treated and untreated with mfAgNPs. As shown in Fig. 4A, all four genes were significantly down-regulated in the planktonic cells, when treated with mfAgNPs. The expression of lasA and lasB were repressed about 79 and 84%, respectively by 25 μg/mL of mfAgNPs. Although the expression of phzA1 and rhlA were comparatively less reduced by 68 and 72%, respectively as compared to lasA and lasB.


Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems.

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

Effect of mfAgNPs on the expression of QS-controlled genes of PAO1.(A) The expression of genes namely lasA, lasB, phzA1, and rhlA, lasI, lasR, rhlI, rhlR, fabH2, and proC (housekeeping gene) was assessed in mfAgNPs treated or untreated control cDNA by RT-qPCR. The relative magnitude of gene expression level was defined as the copy number of cDNA of each gene in the planktonic cells normalized by the copy number of cDNA of the corresponding gene in planktonic cells without mfAgNPs. Error bars indicate the SD of 3 measurements. ***P < 0.001 Vs control. **P < 0.01 Vs the control. *P < 0.05 Vs control. The same volume of H2O was added to the control treatments.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f4: Effect of mfAgNPs on the expression of QS-controlled genes of PAO1.(A) The expression of genes namely lasA, lasB, phzA1, and rhlA, lasI, lasR, rhlI, rhlR, fabH2, and proC (housekeeping gene) was assessed in mfAgNPs treated or untreated control cDNA by RT-qPCR. The relative magnitude of gene expression level was defined as the copy number of cDNA of each gene in the planktonic cells normalized by the copy number of cDNA of the corresponding gene in planktonic cells without mfAgNPs. Error bars indicate the SD of 3 measurements. ***P < 0.001 Vs control. **P < 0.01 Vs the control. *P < 0.05 Vs control. The same volume of H2O was added to the control treatments.
Mentions: To further explore anti-QS potential of mfAgNPs, expression of QS-regulated genes encoding virulence factors of P. aeruginosa PAO1 was studied. The expression of genes such as lasA, lasB, phzA1, and rhlA of PAO1 planktonic cells was analyzed to identify the genes targeted by mfAgNPs and to investigate the molecular mechanism that reduces virulence when mfAgNPs are supplemented. RT-qPCR analysis was to compare the gene expression between PAO1 cells treated and untreated with mfAgNPs. As shown in Fig. 4A, all four genes were significantly down-regulated in the planktonic cells, when treated with mfAgNPs. The expression of lasA and lasB were repressed about 79 and 84%, respectively by 25 μg/mL of mfAgNPs. Although the expression of phzA1 and rhlA were comparatively less reduced by 68 and 72%, respectively as compared to lasA and lasB.

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