Project description:Diquat (DQ), a contact herbicide extensively utilized in both agricultural and non-agricultural domains, exhibits a high correlation with neuronal disorders. Nevertheless, the toxicity and underlying mechanisms associated with exposure to environmental concentrations of DQ remain ambiguous. Here, we report a dose-dependent cellular neurotoxicity of DQ in C. elegans. Firstly, DQ significantly compromised the development and brood size of worms, shortened the lifespan, and caused epidermal abnormalities. An unbiased transcriptomic analysis disclosed several pathways related to cell death and peroxisome homeostasis underlying this organismal-level toxicity. Moreover, the exposure of DQ to C. elegans led to a notable increase of embryonic cell death. Concurrently, DQ exposure specifically caused the loss of dopamine neurons but not two types of neurons in adulthood, which is in accordance with DQ-induced muscle-related defects such as pharyngeal pumping, body bends, and head thrashes.
Project description:This SuperSeries is composed of the following subset Series: GSE21008: Linking toxicant physiological mode of action with induced gene expression changes in Caenorhabditis elegans: atrazine GSE21010: Linking toxicant physiological mode of action with induced gene expression changes in Caenorhabditis elegans: cadmium GSE21011: Linking toxicant physiological mode of action with induced gene expression changes in Caenorhabditis elegans: fluoranthene Refer to individual Series
Project description:Although non-coplanar PCBs are ubiquitous organic chemicals known to induce numerous biological responses and thus are toxic to man and wildlife, little is known about the toxic mode of action. Using PCB52, an ortho-substituted, 2,2’,5,5’-tetrachlorobiphenyl, it was possible to pinpoint the relationship between induced gene expression and observed toxicity in the model nematode Caenorhabditis elegans. Keywords: stress response
Project description:Global challenges with anthelmintic failure and resistance development lends impetus to the development of new nematocides (anthelmintics) with novel mechanism(s) of action. The free-living nematode Caenorhabditis elegans is as an important model organism used for drug discovery and a powerful tool for anthelmintic screening, evaluation and target deconvolution. Previously, we conducted a whole-organism phenotypic screen of the ‘Pandemic Response Box’ (from Medicines for Malaria Venture, MMV) and identified a hit compound, called ABX464, with activity against C. elegans. Here, we explored this nematocidal pharmacophore on C. elegans, and then tested a series of 46 analogues for human hepatoma (HepG2) toxicity, revealing five compounds whose potency was similar or greater than that of ABX464. Subsequently, we employed thermal proteome profiling (TPP), protein structure prediction and an in silico docking algorithm to identify prime ABX464-target candidates. Taken together, the findings from this study contribute significantly to the early-stage drug discovery of a new nematocide based on ABX464. Future work is aimed at validating the ABX464-protein interactions identified here, and at assessing of ABX464 and associated analogues against a panel of parasitic nematodes, towards the development of a new anthelmintic with a novel mechanism of action.
Project description:Physiologically based modelling using DEBtox (dynamic energy budget in toxicology) and transcriptional profiling were used in Caenorhabditis elegans to identify how physiological modes of action, as indicated by effects on system level resource allocation were associated with changes in gene expression following exposure to atrazine (AZ). For AZ, the physiological mode of action predicted by DEBtox was increased cost for maintenance. The transcriptional analysis demonstrated that this increase resulted from effects on DNA integrity as indicated by changes in the expression of genes chromosomal repair. Our results have established that outputs from process based models and transcriptomics analyses can help to link mechanisms of action of toxic chemicals with resulting demographic effects. Such complimentary analyses can assist in the categorisation of chemicals for risk assessment purposes.
Project description:we used Caenorhabditis elegans as a model organism, to investigate the effect of mannose on the lifespan. Using nematode RNAi methods, RT-PCR, RNA-seq and other experimental method, we explored the possible mechanism for how mannose change the lifespan of Caenorhabditis elegans.
Project description:Physiologically based modelling using DEBtox (dynamic energy budget in toxicology) and transcriptional profiling were used in Caenorhabditis elegans to identify how physiological modes of action, as indicated by effects on system level resource allocation were associated with changes in gene expression following exposure to atrazine (AZ). For AZ, the physiological mode of action predicted by DEBtox was increased cost for maintenance. The transcriptional analysis demonstrated that this increase resulted from effects on DNA integrity as indicated by changes in the expression of genes chromosomal repair. Our results have established that outputs from process based models and transcriptomics analyses can help to link mechanisms of action of toxic chemicals with resulting demographic effects. Such complimentary analyses can assist in the categorisation of chemicals for risk assessment purposes. Adults of C. elegans strain GE-31 exposed as biological replicate groups (approx 10,000) to a control and 4 concentrations of atrazine from L1 stage. Replicate populations were sampled 12 hours after the on-set of egg laying and hybridised against a common reference for purposes of normalisation. All experiments were conducted following a reference design with the reference sample compiled from a mixture of RNA extracted from control and cadmium-, fluoranthene-, atrazine- and copper-exposed worms from L1, L4 and adult life-stages. Use of this reference was intended to provide optimal coverage of the spotted genes.
Project description:Effective toxicological testing of the vast number of new and existing chemicals currently in use will require efficient and cost effective methods. We evaluated the utility of a simple, low cost toxicity testing system employing the nematode Caenorhabditis elegans to identify toxicologically relevant changes in gene expression. Dichlorvos and fenamiphos, which are organophosphorous pesticides that inhibit acetylcholinesterase were chosen as model toxicants to test the usefulness of the C. elegans toxicity testing system, and mefloquine, which appears to perturb neuronal Ca++ homeostasis, provided an out-group for analysis. Keywords: gene expression array-based (RNA / in situ oligonucleotide)
Project description:Physiologically based modelling using DEBtox (dynamic energy budget in toxicology) and transcriptional profiling were used in Caenorhabditis elegans to identify how physiological modes of action, as indicated by effects on system level resource allocation were associated with changes in gene expression following exposure to cadmium. For Cd, the physiological mode of action as indicated by DEBtox model fitting was an effect on energy assimilation from food, suggesting that the transcriptional response to exposure should be dominated by changes in the expression of transcripts associated with energy metabolism and the mitochondria. While evidence for effect on genes associated with energy production were seen, an ontological analysis also indicated an effect of Cd exposure on DNA integrity and transcriptional activity. Our results have established that outputs from process based models and transcriptomics analyses can help to link mechanisms of action of toxic chemicals with resulting demographic effects. Such complimentary analyses can assist in the categorisation of chemicals for risk assessment purposes.
Project description:Physiologically based modelling using DEBtox (dynamic energy budget in toxicology) and transcriptional profiling were used in Caenorhabditis elegans to identify how physiological modes of action, as indicated by effects on system level resource allocation were associated with changes in gene expression following exposure to fluoranthene (FA). DEBtox modelling showed an effect of FA on costs for growth and reproduction (i.e. for production of new and differentiated biomass). The microarray analysis supported this effect, showing an effect of FA on protein integrity and turnover that would be expected to have consequences for rates of somatic growth. Our results have established that outputs from process based models and transcriptomics analyses can help to link mechanisms of action of toxic chemicals with resulting demographic effects. Such complimentary analyses can assist in the categorisation of chemicals for risk assessment purposes.