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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

Mycofabrication and characterization of mfAgNPs.(A) Biomass aqueous extract of BRS-07 was challenged with 1 mM AgNO3 solution upto 24 h and development of color due to the excitation of surface plasmon resonance (SPR) at different time TEM intervals. (B) UV-visible absorption spectrum of mfAgNPs at various time intervals. (C) SEM micrograph showing the structure of synthesized mfAgNPs. (D) TEM analysis showing morphology of mfAgNPs that are polydispersed with a roughly spherical shape, crystalline nature, and agglomeration. The micrograph presenting mfAgNPs of various sizes ranges 5–30 nm. (E) FTIR spectrum showing possible interaction between AgNPs and biomolecules of BAE of BRS-07.
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f1: Mycofabrication and characterization of mfAgNPs.(A) Biomass aqueous extract of BRS-07 was challenged with 1 mM AgNO3 solution upto 24 h and development of color due to the excitation of surface plasmon resonance (SPR) at different time TEM intervals. (B) UV-visible absorption spectrum of mfAgNPs at various time intervals. (C) SEM micrograph showing the structure of synthesized mfAgNPs. (D) TEM analysis showing morphology of mfAgNPs that are polydispersed with a roughly spherical shape, crystalline nature, and agglomeration. The micrograph presenting mfAgNPs of various sizes ranges 5–30 nm. (E) FTIR spectrum showing possible interaction between AgNPs and biomolecules of BAE of BRS-07.

Mentions: It is reported that the active substances of BAE of fungi include oxidoreductases and quinone extracellular process2627. These metabolites play a role in the reduction of metal ions and efficient stabilization of nanoparticles. R. arrhizus BRS-07 was isolated from the roots of Ashawgandha (Withania somnifera L.) and characterized at morphological as well as molecular levels (Supplementary figures 1A, B, C, and D). AgNO3, upon incubation with BAE of the fungus for 24 h, turned dark brown color (Supplementary figure 2A). The development of color is due to the excitation of surface plasmon resonance (SPR) exhibited by the NPs28. Interestingly, no color development was observed, when culture media was incubated with AgNO3 for 24 h (Supplementary figure 2B). The intensity of colour was increased with the increase in time of incubation (Fig. 1A). The UV-vis spectrum showed a signature peak of AgNPs at 410 nm due to SPR in AgNPs (Fig. 1B)1729. It can be hypothesized that the synthesis of mfAgNPs might have happened due to the reduction of metal ions by metabolites present in BAE of BRS-07.


Mycofabricated biosilver nanoparticles interrupt Pseudomonas aeruginosa quorum sensing systems.

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

Mycofabrication and characterization of mfAgNPs.(A) Biomass aqueous extract of BRS-07 was challenged with 1 mM AgNO3 solution upto 24 h and development of color due to the excitation of surface plasmon resonance (SPR) at different time TEM intervals. (B) UV-visible absorption spectrum of mfAgNPs at various time intervals. (C) SEM micrograph showing the structure of synthesized mfAgNPs. (D) TEM analysis showing morphology of mfAgNPs that are polydispersed with a roughly spherical shape, crystalline nature, and agglomeration. The micrograph presenting mfAgNPs of various sizes ranges 5–30 nm. (E) FTIR spectrum showing possible interaction between AgNPs and biomolecules of BAE of BRS-07.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Mycofabrication and characterization of mfAgNPs.(A) Biomass aqueous extract of BRS-07 was challenged with 1 mM AgNO3 solution upto 24 h and development of color due to the excitation of surface plasmon resonance (SPR) at different time TEM intervals. (B) UV-visible absorption spectrum of mfAgNPs at various time intervals. (C) SEM micrograph showing the structure of synthesized mfAgNPs. (D) TEM analysis showing morphology of mfAgNPs that are polydispersed with a roughly spherical shape, crystalline nature, and agglomeration. The micrograph presenting mfAgNPs of various sizes ranges 5–30 nm. (E) FTIR spectrum showing possible interaction between AgNPs and biomolecules of BAE of BRS-07.
Mentions: It is reported that the active substances of BAE of fungi include oxidoreductases and quinone extracellular process2627. These metabolites play a role in the reduction of metal ions and efficient stabilization of nanoparticles. R. arrhizus BRS-07 was isolated from the roots of Ashawgandha (Withania somnifera L.) and characterized at morphological as well as molecular levels (Supplementary figures 1A, B, C, and D). AgNO3, upon incubation with BAE of the fungus for 24 h, turned dark brown color (Supplementary figure 2A). The development of color is due to the excitation of surface plasmon resonance (SPR) exhibited by the NPs28. Interestingly, no color development was observed, when culture media was incubated with AgNO3 for 24 h (Supplementary figure 2B). The intensity of colour was increased with the increase in time of incubation (Fig. 1A). The UV-vis spectrum showed a signature peak of AgNPs at 410 nm due to SPR in AgNPs (Fig. 1B)1729. It can be hypothesized that the synthesis of mfAgNPs might have happened due to the reduction of metal ions by metabolites present in BAE of BRS-07.

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