Sublethal Effects of Ionic and Nanogold on the Nematode Caenorhabditis elegans

Abstract

The nematode Caenorhabditis elegans is used as an ecotoxicological model species in both aqueous medium and solid substrates. It is easy and of low cost to maintain in the laboratory and it produces hundreds of offspring within a short period of time. It also has a small body size (1 mm), making it possible for in vivo assays to be conducted in 12-well plates. Engineered nanomaterials (ENMs) are a class of emerging pollutants. Nanogold (nAu) is used in many consumer products and in vivo drug delivery. These materials can be released into the aquatic environment during production or discarding of consumer products. As nAu is insoluble in water, the sediment would become the final depository for the materials. It has become increasingly important to use sediment dwelling organisms to screen for possible toxicity of these ENMs. In this study C. elegans was exposed to a range of concentrations of nAu and ionic gold in M9-media, acting as a substitute for pore water. After 96-hour growth, fertility and reproduction were determined. Internal structure damage and internalisation of particles in C. elegans were determined by using SEM and CytoViva® Darkfield Imaging. From these images the nanomaterials are distributed around the oocytes in the reproductive organs, as well as the pharynx. Results obtained indicate that nAu affects reproduction more than growth due to internal gonad damage, albeit at very high exposure concentrations, indicating no toxicity at environmentally relevant concentrations. Ionic Au is more toxic than nAu and effects fertility and reproduction due to ion release. These results give more information regarding the toxicity and in vivo uptake of nAu and form part of an environmental risk assessment of ENMs.

Engineering the surface of graphene oxide with bovine serum albumin for improved biocompatibility inCaenorhabditis elegans

“…Mounting pre-clinical studies have shown that ENMs cause wild-type toxicity in C. elegans. [49][50][51][52][53][54][55][56] We rst investigated the effect of acute exposure to GO/GO-BSA on wild-type N2 nematodes. Acute exposure to GO/GO-BSA (0.5-100 mg LÀ1) did not affect the normal lifespan as shown in Fig.…”

Current situation and future prognosis of health, safety and environment risk assessment of nanomaterials in South Africa

“…Subsequently, South African and other international researchers have been evaluating the applicability of standardised toxicity tests for inter alia nematodes 38 , enchytraeid potworms 39 , aquatic invertebrates and fish 40,41 . Using these standardised OECD protocols, local studies conducted as part of the safety testing of AuNPs revealed that nanomaterials had lower toxicity than their chemical equivalents.…”

The Effect of Internalized Paramagnetic Nanoparticles on Caenorhabditis elegans Locomotion in the Presence of Magnetic Field

“…C. elegans nematodes are shown to be an excellent model for evaluating the impact of nanomaterials on animal physiology and behavior [60]. More specifically, metal nanoparticles of various types have been used to evaluate particle toxicity using C. elegans [42,[61][62][63][64][65]. Particle coating and size, worm developmental stage, and duration of exposure have been shown to the affect translocation of particles in various tissues of the worm's body [42,61,66].…”