lasR/rhIR expression linked to Quorum Sensing Mediated Biofilm formation in Pseudomonas aeruginosa using gold nano particles conjugated with ethnobotanical extracts
Date
2019
Authors
Alexander T. Velasco, Jr
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Abstract
The rapid emergence of multidrug resistant bacteria endangers the efficacy of antibiotics, which leads to the search of novel anti-infective measures that do not rely in antibiotics. Qurom sensing inhibition (QSI) presents potentials in making straightforward approach of disrupting cell to cell communication in bacteria, thereby decreasing virulence factors such as biofilm formation. To assess QSI of gold nanoparticles conjugated with ethnobotanical extracts (AuNPs + CEs) against P. aeruginosa, as a preliminary test, antibacterial activity was assessed and AuNPs +CEs that inhibited antibacterial activity were not used in the biofilm formation assay in order to rule out antimicrobial decrease in biofilm formation. RNA of bacterial sample treated with AuNPs + CEs with biofilm formation inhibitory activity was subjected to gene expression analysis. The results revealed that all AuNPs + CEs used in the microtier biofilm formation assay showed a significant decrease in biofilm formation in P. aeruginosa. Gene expression analysis of lasR and rhlR revealed that AuNPs + CEs that exhibited decrease in biofilm formation also have downregulated expression of lasR and rhlR an indication of quorum sensing mediated decrease in virulence. Furthermore, the results showed lower expression of lasR in samples treated with AuNPs + CEs, as compared to the previous study and results of gene expression analysis of lasR in P. aeruginosa treated with crude extracts of the ethnobotanicals. This result presents the rule of gold nanoparticle in enhancing the delivery of bioactive compounds present in the ethnobotanicals, with QSI activity against P. aeruginosa. hence, the result offers the potential of AuNPs + CEs in QSI of disease causing human pathogen.