Project description:To understand molecular mechanisms of the joint effects of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), both widely used ordnance compounds, we constructed a microarray consisting of 4,032 cDNA isolated from the earthworm Eisenia fetida using the suppressive subtractive hybridization technique. Worms were exposed to TNT-, RDX-, or TNT+RDX-spiked soil for 28 days (TNT 50 mg/kg, RDX 30 mg/kg). Keywords: Combined toxicity of TNT and RDX to earthworm (Eisenia fetida)
Project description:To understand molecular mechanisms of the chronic, sublethal toxicity of 2,4,6-trinitrotoluene (TNT), a widely used ordnance compound of public concerns, we constructed a microarray consisting of 4,032 cDNA isolated from the earthworm Eisenia fetida using the suppressive subtractive hybridization technique. Worms were exposed to a gradient of TNT-spiked soil for 28 days. Based on the reproduction response to TNT, four treatments, i.e., control, 7, 35 and 139 ppm, were selected for gene expression studies. Keywords: Sublethal toxicity of TNT (dose-response) to earthworm (Eisenia fetida)
Project description:To understand molecular mechanisms of the joint effects of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), both widely used ordnance compounds, we constructed a microarray consisting of 4,032 cDNA isolated from the earthworm Eisenia fetida using the suppressive subtractive hybridization technique. Worms were exposed to TNT-, RDX-, or TNT+RDX-spiked soil for 28 days (TNT 50 mg/kg, RDX 30 mg/kg). Keywords: Combined toxicity of TNT and RDX to earthworm (Eisenia fetida) We analyzed 40 arrays for 4 treatments (control, TNT 50ppm, RDX 30ppm, TNT 50ppm + RDX 30ppm) with 5 biological replicates per treatment using an interwoven loop design.
Project description:Purpose: We studied the potential effects of lindane aging in soil on model earthworm Eisenia fetida at the transcriptomic level. Methods: transcriptomes of earthworms were generated by RNA sequencing using Illumina Hiseq Xten platform. Results: There were 1325 DE unigenes in G2 (1074 up and 251 down), 784 DE unigenes in G3 (457 up and 327 down), 3658 DE unigenes in G4 (2294 up and 1364 down), and 1511 DE unigenes in G5 (929 up and 582 down) compared with G1. Except in G2, lindane exposure caused significant impacts on cholinergic and GABAergic synaptic transmission in earthworms in other groups. The metabolic processes of ACh were also altered. It was of note that the term positive regulation of locomotion (GO:0040017) in G5 could be regarded as the phenotype of the interaction of two NTs. Conclusions: We found that aging of lindane prior to exposure promoted the disrupting effects of lindane on earthworm neurotransmission.
Project description:Earthworms show a wide spectrum of regenerative potential with certain species like Eisenia fetida, a terrestrial redworm, capable of regenerating more than two-thirds of their body while other closely related species, such as Paranais litoralis seem to have lost this ability. Earthworms belong to the phylum annelida, in which the genomes of the marine oligochaete Capitella telata, and the freshwater leech Helobdella robusta have been sequenced and studied. Herein, we report the de novo assembled transcriptome of Eisenia fetida (Indian isolate), along with an analysis of the transcriptomic changes during regeneration. We also used de novo assembled RNAseq data to identify genes that are differentially expressed during regeneration, both in the newly regenerating cells and in the adjacent tissue.
Project description:The earthworm Eisenia fetida is one of the most used species in standardized soil ecotoxicity tests. Endpoints such as survival, growth and reproduction are ecologically relevant but provide little mechanistic insight into the toxicity pathways, especially at the molecular level. To better understand toxicological modes of action and to facilitate the development of molecular biomarkers, we have obtained 30,245 unique EST sequences from E. fetida and have designed a novel microarray with 15,119 60-mer oligonucleotide probes. These probes target the unique non-redundant EST sequences identified in E. fetida. Using this array we have profiled gene expression of E. fetida after exposure to CL-20, a cage cyclic nitramine previously found exhibiting reversible neurotoxicity to worms. Worms were exposed for 6 days to CL-20. Half of the exposed worms were allowed to recover in a clean environment for 7 days. Electrophysiological analysis showed that the conduction velocity of worm medial giant nerve fiber was significantly decreased after 6-d exposure to CL-20, and that giant nerve fiber function was restored at the end of the 7-d recovery period. Total RNA samples isolated from four treatment groups (6 replicates per group), i.e., 6-d control, 6-d exposed, 13-d control and 6-d exposed with 7-d recovery, were analyzed using the new 15K oligo array. Bioinformatics and statistical analyses have identified specific neurological pathways affected by CL-20 and recovery of these pathways after CL-20 removal. These results provide significant insights on the CL-20 toxic mode of action and how earthworms can recover from chemical stressors.
Project description:Background: Earthworms are essential for a healthy soil ecosystem, performing key functions such as bioturbation. The soil ecosystem can be challenged by natural toxins such as isothiocyanates (ITC), secondary metabolites produced by many commercial crops. This study investigated the effects of the natural toxin, 2-phenylethyl isothiocyanate on the earthworm Eisenia andrei using an ecotoxicogenomics approach that combined standardised ecotoxicological testing with gene expression analyses. Results and discussion: Exposure to 2-Phenylethyl ITC reduced both survival and reproduction of E. andrei in a dose-dependent manner, with an EC50 (reproduction) value of 556 nmol/g soil. Cross-species comparative genomic hybridisation validated the applicability of an existing 4x44k E. fetida microarray to E. andrei. Gene expression profiles revealed the importance of metallothionein (mt) as an early warning signal when E. andrei is exposed to low concentrations of 2-phenylethyl ITC. Allignment of these mt genes with the mt-2 gene of Lumbricus rubellus showed that there must at least have 2 mt genes in the Eisenia sp. genome. At high exposure concentrations of 2-phenylethyl ITC gene expression was mainly affected by inhibiting chitinase activities, inducing an oxidative stress response, and stimulating energy metabolism. KEGG pathway analysis, furthermore, implied that the high concentration may cause impaired light sensitivity, angiogenesis (e.g. wound healing), olfactory perception (olfaction), learning and memory. Conclusions: Increased levels of isothiocyanates may be found in the field in the near future. Risks of such compounds should be carefully investigated before allowing them to enter the soil on a large scale. This is the first study to investigate the effects of an isothiocyanate on an earthworm both on the ecotoxicological and genomic level. Three-exposure experiment; Acetone control vs.EC10 vs.EC50 exposed animals. Biological replicates: 4 replicates for each exposure. Technical replicates: 2 replicates for each exposure