Effects of low-level engineered nanoparticles on the quorum sensing of Pseudomonas aeruginosa PAO1

Abstract

The toxicity of engineered nanoparticles (ENPs) on bacteria has aroused much interest. However, few studies have focused on the effects of low-level ENPs on bacterial group behaviors that are regulated by quorum sensing (QS). Herein, we investigated the effects of nine ENPs (Ag, Fe, ZnO, TiO, SiO, FeO, single-wall carbon nanotubes (SWCNTs), graphene oxide (GO), and C) on QS in Pseudomonas aeruginosa PAOl. An ENP concentration of 100 μg L did not impair bacterial growth. However, concentrations of 100 μg L of Ag and GO ENPs induced significant increases in 3OC-HSL in the culture and significantly promoted protease production and biofilm formation of PAO1. C-HSL synthase and its transcription factors were less sensitive to 100 μg L Ag and GO ENPs compared with 3OC-HSL. Fe ENPs induced a significant increase in the 3OC-HSL concentration, similar to Ag and GO ENPs. However, Fe ENPs did not induce any significant increase in protease production or biofilm formation. Different size distributions, chemical compositions, and aggregation states of the ENPs had different effects on bacterial QS. These whole circuit indicators could clarify the effects of ENPs on bacterial QS. This study furthers our understanding of the effects of low-level ENPs on bacterial social behaviors.

Biofilm inhibition and anti-quorum sensing activity of phytosynthesized silver nanoparticles against the nosocomial pathogen Pseudomonas aeruginosa

“…There was no difference in the growth pattern of P. aeruginosa PAO1 treated with Pb-AgNPs compared to the control cells not treated with Pb-AgNPs (Supplemental Figure 2, Supplemental material available online). Pb-AgNPs at the above mentioned concentrations had no effect on the growth of the test strain, suggesting its possible application as a true anti-QS agent (Li et al 2018).…”

Chronic Exposure to Low Concentration of Graphene Oxide Increases Bacterial Pathogenicity via the Envelope Stress Response

“…Additionally, 100 μg/L GO significantly promoted biofilm and protease production by P. aeruginosa PAO1 after 24 h of incubation . Compensatory release of proteases and biofilm generation were suggested as adaptive responses of P.…”

Soil phyllosilicate and iron oxide inhibit the quorum sensing of Chromobacterium violaceum

“…Here, we propose that the adsorption of signal molecules onto mineral surfaces is a universal mechanism for their reduction in the environment. The difference in physicochemical properties including the surface area, charge and adsorption capacity is the main reason behind the differences in QS quenching among the three clay minerals (Masiello et al, 2013;Duran et al, 2016;Li et al, 2018). Several mechanisms including reactive oxygen species, surface adhesion and toxic ions have been proposed for the explanation of mineral toxicity (Londono et al, 2017;Wang et al, 2017).…”

“…As a consequence, it is speculated that the cellular density and QS-related enzyme activity may be hindered in the presence of these mineral particles. On the other hand, the minerals can reduce the extracellular concentration of signal molecules by surface adsorption (Masiello et al, 2013;Li et al, 2018). It was reported that the adsorption capacities of signal molecules, acyl-homoserine lactones (AHLs), onto minerals were in the order: montmorillonite > kaolinite > goethite (Liu et al, 2015).…”