Transcriptomic analysis of RDX and TNT interactive sublethal effects in the earthworm Eisenia fetida

Abstract

Background: Explosive compounds such as TNT and RDX are recalcitrant contaminants often found co-existing in the environment. In order to understand the joint effects of TNT and RDX on earthworms, an important ecological and bioindicator species at the molecular level, we sampled worms (Eisenia fetida) exposed singly or jointly to TNT (50 mg/ kg soil) and RDX (30 mg/kg soil) for 28 days and profiled gene expression in an interwoven loop designed microarray experiment using a 4k-cDNA array. Lethality, growth and reproductive endpoints were measured.

Conserved toxic responses across divergent phylogenetic lineages: a meta-analysis of the neurotoxic effects of RDX among multiple species using toxicogenomics

“…Acute exposures in Northern bobwhite quail also produced seizures and anemic effects, as well as altered blood chemistry. Liver edema was observed in both quail and rat exposures (Meyer et al 2005;Johnson et al 2007;Quinn et al 2009) while swelling/edema and constriction/autotomy was observed in high dose exposures of earthworms (Gong et al 2008). Neurotoxicity symptoms observed in earthworms exposed to RDX include rigidity/shrinking (chlonic seizure) and significantly reduced impulse conduction in medial (MGF) and lateral (LGF) giant nerve fiber pathways (Gong et al 2008).…”

“…Once it enters the environment, RDX has the potential to affect many species. Impacts on the nervous system have been observed in a variety of species exposed to RDX including humans, dogs, rats, birds and earthworms (Goldberg et al 1992;Talmage et al 1999;Gong et al 2008;Gust et al 2009). Williams et al (2011) recently demonstrated that the molecular initiating event for neurotoxicity is binding of RDX to the GABA A (c-aminobutyric acid) receptor (GABA A R) where it blocks membrane repolarization.…”

Toxicogenomics Applied to Ecological Risk Assessment

“…To date, fish, particularly zebrafish and fathead minnow, and Daphnia magna, appear to be the most common model organisms for ecotoxicogenomics studies employing DNA microarrays. Nonetheless, there are a few rare examples of studies conducted with birds (e.g., Yeung et al, 2007), amphibians (Helbing et al, 2007a,b;Page et al, 2007), mussels (Dondero et al, 2006), and terrestrial invertebrates (Gong et al, 2007(Gong et al, , 2008Bundy et al, 2008). Additionally transcriptomic methods have been used to study the effects of contaminants and other environmental stressors on phytoplankton (Chlamydomonas reinhardtii ;Jamers et al, 2006) and corals Morgan et al, 2005).…”

“…A variety of "emerging-contaminants" of concern have been studied, including perfluorinated chemicals (Yeung et al, 2007;Wei et al, 2008), brominated diphenyl ethers (Hook et al, 2006), pharmaceuticals (van der Ven et al, 2006, and even nanoparticles (Griffitt et al, 2007). Ordnance-related chemicals and a number of pesticides have also been the subject of transcriptomic investigations (Hook et al, 2006;Wintz et al, 2006;Finne et al, 2007;Soetaert et al, 2007;Gong et al, 2008). Finally, microarrays have been employed to investigate responses of aquatic organisms to nonchemical stressors, including temperature, salinity, hypoxia, dissolved organic carbon, hardness, UV radiation, and sedimentation Kassahn et al, 2007;Larsen et al, 2007;Mager et al, 2008;Martinovic et al, 2009).…”

“…Transcriptomic results for Daphnia magna were anchored to embryo abnormalities and carapax length in one study (Soetaert et al, 2007) and population growth rates in another (Connon et al, 2008). Gene expression changes in earthworms exposed to ordnance chemicals were related to survival, growth, and reproduction (Gong et al, 2008). Santos et al (2007) linked transcriptional responses of zebrafish to EE2 with histological, morphological, and reproductive endpoints, including measures of egg production, fertilization success, and sperm quality.…”