Ecotoxicity of Silver Nanoparticles on the Soil Nematode Caenorhabditis elegans Using Functional Ecotoxicogenomics

Abstract

In the present study, the ecotoxicity of silver nanoparticles (AgNPs) was investigated in Caenorhabditis elegans using survival, growth, and reproduction, as the ecotoxicological endpoints, as well as stress response gene expression. Whole genome microarray was used to screen global changes in C. elegans transcription profiles after AgNPs exposure, followed by quantitative analysis of selected genes. The integration of gene expression with organism and population level endpoints was investigated using C. elegans functional genomics tools, to test the ecotoxicological relevance of AgNPs-induced gene expression. AgNPs exerted considerable toxicity in C. elegans, most clearly as dramatically decreased reproduction potential. Increased expression of the superoxide dismutases-3 (sod-3) and abnormal dauer formation protein (daf-12) genes with 0.1 and 0.5 mg/L of AgNPs exposures occurred concurrently with significant decreases in reproduction ability. Overall results of functional genomic studies using mutant analyses suggested that the sod-3 and daf-12 gene expressions may have been related to the AgNPs-induced reproductive failure in C. elegans and that oxidative stress may have been an important mechanism in AgNPs toxicity.

Metal‐based nanoparticles in soil: Fate, behavior, and effects on soil invertebrates

“…A recent study showed that the nematode C. elegans had increased ROS formation when exposed to 1 mg/L Ag NPs (20-30 nm in K-media), whereas no increase in ROS production was seen from the matching AgNO 3 exposure [80]. This confirms indications from previous studies in C. elegans by the same authors in which Ag NPs caused reproductive toxicity, which was related to oxidative stress, whereas no effects were seen on survival and growth (14-20 nm Ag NPs up to 0.5 mg/L in K-media) [81]. Although liquid K-media has obvious practical advantages, some aggregation will occur (because of high ionic strength) and prevent effective high-concentration exposures.…”

Metalloproteins and phytochelatin synthase may confer protection against zinc oxide nanoparticle induced toxicity in Caenorhabditis elegans

“…and silica nanoparticles (Wang et al, 2009;Roh et al, 2009;Kim et al, 2008;Pluskota et al, 2009). In general, NPs were shown to reduce nematode lifespan, possibly in response to the particle mediated generation of reactive oxygen species (ROS), and induce a premature degeneration of reproductive organs.…”

“…Others have reported that nanomaterials can cause a reduction in nematode reproduction (Wang et al, 2009;Roh et al, 2009;Kim et al, 2008;Pluskota et al, 2009 Table 2). …”

“…The harmful effects of ZnONPs are driven by their physicochemical properties (dissolution and formation rate, the morphology and chemical composition, surface reactivity, particle number) and the resulting physical damage caused by the aggregation and agglomeration of nanoparticles (Bai et al, 2010;Jiang et al, 2009;Zhang et al, 2010. The bio-kinetic behaviour and in vivo toxicity of ZnONP exposure has, to date, been investigated in several non-mammalian systems including in vitro cell-based assays (Sharma et al, 2012a,b;Ahamed et al, 2011;Wu et al, 2010), bacteria (Li et al, 2011;Reddy et al, 2007), algae (Franklin et al, 2007), plants (Lin and Xing, 2007), crustaceans (Poynton et al, 2011), fish (Bai et al, 2010), earthworms (Hooper et al, 2011) and nematodes (Khare et al, 2011;Ma et al, 2009;Ma et al, 2011;Roh et al, 2009;Wu et al, 2013). The nematode Caenorhabditis elegans, a powerful model organism due to the availability of a completely sequenced genome (Hillier et al, 2005) and many molecular genetics tools has been used in ecotoxicological research to study the molecular to organismal level responses to ROS and heavy metal challenges (Roh et al, 2006;Hughes and Sturzenbaum 2007;Swain et al, 2004Swain et al, , 2010Zeitoun-Ghandour et al, 2010; The roles of the metalloproteins metallothionein (MT) and phytochelatin (PC) are Furthermore, ZnONP mediated toxicity may result from the release of free ionic zinc (George et al 2010;Li et al, 2012;Poynton et al, 2011;Wang et al, 2009), which induces cellular damage via the generation of free reactive oxygen species (ROS), which in turn can promote pro-inflammatory effects Mocchegiani et al, 2011).…”

In vitro and in vivo toxicity assessment of nanoparticles

“…In D. melanogaster, they are known as oxidative stress, heat shock stress, upregulation of p53 proteins [39]. In Caenorhabditis elegans, they are known for oxidative stress and a decrease in reproduction potential [203].…”