Effect of gold nanoparticles and ciprofloxacin on microbial catabolism: a community‐based approach

Abstract

The effect of gold nanoparticles (AuNPs) and ciprofloxacin on the catabolism of microbial communities was assessed. This was accomplished through an ex situ methodology designed to give a priori knowledge on the potential for nanoparticles, or other emerging contaminants, to affect the catabolic capabilities of microbial communities in the environment. Microbial communities from a variety of sources were incubated with 31 prespecified carbon sources and either National Institute of Standards and Technology reference material 10-nm AuNPs or ciprofloxacin on 96-well microtiter plates. From the ciprofloxacin study, dose-response curves were generated and exemplified how this method can be used to assess the effect of a toxicant on overall catabolic capabilities of microbial communities. With 10-nm AuNPs at concentrations ranging from 0.01 µg/mL to 0.5 µg/mL, rhizosphere communities from Typha roots were only slightly catabolically inhibited at a single concentration (0.05 µg/mL); no effects were seen on wetland water communities, and a minor positive (i.e., enhanced catabolic capabilities) effect was observed for loamy soil communities. This positive effect might have been because of a thin layer of citrate found on these AuNPs that initiated cometabolism with some of the carbon sources studied. Under the conditions considered, the possible adverse effects of AuNPs on the catabolic capabilities of microbial communities appears to be minimal.

Gold Nanomaterial Uptake from Soil Is Not Increased by Arbuscular Mycorrhizal Colonization of Solanum Lycopersicum (Tomato)

“…However, the data collected here demonstrate robust AMF colonization of the 76R plants compared to typical values in unexposed plants [ 6 , 11 ], despite rhizoplane accumulation. This finding, which is similar to other recent work examining the effects of Au ENMs on rhizosphere biota [ 30 ], suggests that AMF colonization may be relatively resistant to potential effects induced by at least Au ENM accumulation at the rhizoplane over the time periods tested here.…”

Amendment of Agricultural Soil with Metal Nanoparticles: Effects on Soil Enzyme Activity and Microbial Community Composition

“…There are also studies reporting no or minimal effect of ENPs such as nZnO and nanosized zerovalent Cu, nTiO 2 , and nanosized Al 2 O 3 and SiO 2 on the soil microbial community . Weber et al showed that 10 nm citrate-coated nAu enhanced the catabolic activity of microbial communities from loamy soil . The observed impacts of applied ENPs vary depending on the composition, dose, and properties of ENPs such as coating, size, and age or physicochemical properties of the receiving soils …”

“…23 Weber et al showed that 10 nm citrate-coated nAu enhanced the catabolic activity of microbial communities from loamy soil. 37 The observed impacts of applied ENPs vary depending on the composition, dose, and properties of ENPs such as coating, size, 24 and age 38 or physicochemical properties of the receiving soils. 25 In this study, we systematically investigated the impact of metal ENPs and their dissolved ions on soil enzyme activity and microbial community composition of a biosolid-amended agricultural soil.…”

Separation, Sizing, and Quantitation of Engineered Nanoparticles in an Organism Model Using Inductively Coupled Plasma Mass Spectrometry and Image Analysis

“…These concentrations were determined by a recent study which determined the annual predicated environmental concentrations of AuNPs in surface waters for the UK and US as 4.68 and 4.7 × 10 –6 ng/mL, respectively . The concentrations used in this study were several orders of magnitude higher than those predicted but still substantially lower than those often used in other nano-ecotoxicology studies which typically utilize concentrations near or above 1 mg/L Scheme illustrates the traditional protocol for C.…”

“…48 The concentrations used in this study were several orders of magnitude higher than those predicted but still substantially lower than those often used in other nanoecotoxicology studies which typically utilize concentrations near or above 1 mg/L. 49 Scheme 1 illustrates the traditional protocol for C. elegans AuNP exposure and postexposure sample processing. This approach utilizes water rinsing between centrifugation steps in an effort to remove cuticle-adsorbed AuNPs and AuNPs freely suspended in dispersion media.…”