Skip to Content
Merck
  • Silver nanoparticle inhibition of polycyclic aromatic hydrocarbons degradation by Mycobacterium species RJGII-135.

Silver nanoparticle inhibition of polycyclic aromatic hydrocarbons degradation by Mycobacterium species RJGII-135.

Letters in applied microbiology (2013-11-30)
S R Mueller-Spitz, K D Crawford
ABSTRACT

Polycyclic aromatic hydrocarbons (PAH) are a common environmental contaminant originating from both anthropogenic and natural sources. Mycobacterium species are highly adapted to utilizing a variety of PAH. Silver nanoparticles (AgNP) are an emerging contaminant that possess bactericidal properties, interferes with the bacterial membrane and alters function. Mycobacterium sp. strain RJGII-135 provided a model bacterium to assess changes in carbon metabolism by focusing on PAH degradation, which is dependent upon passive uptake of hydrophobic molecules into the cell membrane. A mixture of 18 PAH served as a complex mixture of carbon sources for assessing carbon metabolism. At environmentally relevant PAH concentrations, RJGII-135 degraded two-, three-, and four-ring PAH within 72 h, but preferentially attacked phenanthrene and fluorene. Total cell growth and PAH degradation were successively reduced when exposed to 0·05-0·5 mg 1(-1) AgNP. However, 0·05 mg l(-1) AgNP inhibited degradation of naphthalene, acenaphthylene and acenaphthalene. RJGII-135 retained the ability to degrade the methylated naphthalenes regardless of AgNP concentration suggesting that proteins involved in dihydrodiol formation were inhibited. The reduced PAH metabolism of RJGII-135 when exposed to sublethal concentrations of AgNP provides evidence that nanoparticle pollution could alter carbon cycling in soils, sediment and aquatic environments. Silver nanoparticle (AgNP) pollution threatens bacterial-mediated processes due to their antibacterial properties. With the widespread commercial use of AgNP, continued environmental release is inevitable and we are just beginning to understand the potential environmental ramifications of nanoparticle pollution. This study examined AgNP inhibition of carbon metabolism through the polycyclic aromatic hydrocarbon degradation by Mycobacterium species RJGII-135. Sublethal doses altered PAH metabolism, which is dependent upon cell membrane properties and intracellular proteins. The changed carbon metabolism when exposed to sublethal doses of AgNP suggests broad impacts of this pollution on bacterial carbon cycling in diverse environments.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Silver, colloidal, 65-75% Ag basis
Sigma-Aldrich
Silver, wire, diam. 0.1 mm, 99.9% trace metals basis
Sigma-Aldrich
Silver, foil, thickness 1.0 mm, 99.99% trace metals basis
Sigma-Aldrich
Silver, nanopowder, <150 nm particle size, 99% trace metals basis
Sigma-Aldrich
Silver nanowires, diam. × L 200  nm × 10 μm, 0.5% (isopropyl alcohol suspension)
Silver, foil, 1m coil, thickness 0.035mm, as rolled, 99.95+%
Sigma-Aldrich
Silver, conductive paste
Sigma-Aldrich
Silver, shot, 1-3 mm, ≥99.99% trace metals basis
Silver, foil, not light tested, 50x50mm, thickness 0.005mm, 99.97%
Silver, foil, not light tested, 100x100mm, thickness 0.008mm, 99.95+%
Silver, foil, not light tested, 150x150mm, thickness 0.006mm, 99.97%
Silver, foil, not light tested, 50x50mm, thickness 0.01mm, 99.95+%
Silver, insulated wire, 1m, conductor diameter 0.075mm, insulation thickness 0.010mm, nylon insulation, 99.99%
Silver, foil, not light tested, 50x50mm, thickness 0.008mm, 99.95+%
Silver, insulated wire, 2m, conductor diameter 0.125mm, insulation thickness 0.0125mm, polyester insulation, 99.99%
Silver, foil, not light tested, 50x50mm, thickness 0.015mm, 99.97%
Silver, insulated wire, 5m, conductor diameter 0.125mm, insulation thickness 0.0125mm, polyester insulation, 99.99%
Silver, insulated wire, 10m, conductor diameter 0.075mm, insulation thickness 0.010mm, nylon insulation, 99.99%
Silver, insulated wire, 2m, conductor diameter 0.25mm, insulation thickness 0.005mm, polyurethane insulation, 99.99%
Silver, foil, not light tested, 50x50mm, thickness 0.025mm, annealed, 99.95+%
Silver, insulated wire, 50m, conductor diameter 0.25mm, insulation thickness 0.015mm, epoxy insulation, 99.99%
Silver, insulated wire, 5m, conductor diameter 0.125mm, insulation thickness 0.015mm, PTFE (polytetrafluoroethylene) insulation, 99.99%
Silver, wire reel, 50m, diameter 0.05mm, annealed, 99.99%
Silver, wire reel, 1m, diameter 0.050mm, gold plated, 99.99%
Silver, wire reel, 0.5m, diameter 0.25mm, as drawn, 99.997%
Silver, wire reel, 5m, diameter 0.015mm, annealed, 99.99%
Silver, wire reel, 2m, diameter 2.0mm, annealed, 99.99%
Silver, foil, 50x50mm, thickness 0.1mm, annealed, 99.95+%
Silver, wire reel, 50m, diameter 0.35mm, annealed, 99.99%
Silver, wire reel, 0.5m, diameter 0.8mm, as drawn, 99.99%