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: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: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. Adults of C. elegans strain GE-31 exposed as biological replicate groups (approx 10,000) to a control and 4 concentrations of cadmium from L1 stage. Replicate populations were sampled 12 hours after the on-set of egg laying and hybridised against a common oligonucleotide 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: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. Adults of C. elegans strain GE-31 were exposed as biological replicate groups (approx 10,000) to a control and 4 concentrations of fluoranthene from L1 stage. Replicate populations were sampled 12 hours after the on-set of egg laying and hybridised against a common oligonucleotide 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: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.
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: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.