Project description:The goal of the study was to investigate gene expression differences in Hyalella azteca exposed to pyrethroid insecticides and compare a laboratory strain to a wild population believed to be resistant to the pesticides. H. azteca reared in the laboratory at the University of CA, Berkeley (UCB) were exposed to cyfluthrin, a commerical pyrethroid insecticide for 96-h. A wild population collected from Grayson Creek (GC), CA was reared in the laboratory for several days and also exposed to cyfluthrin. Toxicity testing revealed that GC animals were two orders of magnitude less sensitive to cyfluthrin compared to the laboratory animals with the no observed effect concentration (NOEC) for UCB = 0.4 ng/L and GC= 170 ng/L. Unexposed, control animals and animals exposed to 0.4 ng/L (GC and UCB) or 170 ng/L cyfluthrin were collected following 96-h treatments. Differences in gene expression were measured using a custom Hyalella azteca microarray. Gene expression profiles revealed that laboratory H. azteca responded to cyfluthrin through differential expression of genes involved in neurological system processes. In contract, H. azteca from Grayson Creek showed a pattern of oxidative stress through the differential expression of glutathione-S-transferases, heat shock proteins, and other genes involved in oxidation-reduction processes.
Project description:The goal of the study was to investigate gene expression differences in Hyalella azteca exposed to pyrethroid insecticides and compare a laboratory strain to a wild population believed to be resistant to the pesticides. H. azteca reared in the laboratory at the University of CA, Berkeley (UCB) were exposed to cyfluthrin, a commerical pyrethroid insecticide for 96-h. A wild population collected from Grayson Creek (GC), CA was reared in the laboratory for several days and also exposed to cyfluthrin. Toxicity testing revealed that GC animals were two orders of magnitude less sensitive to cyfluthrin compared to the laboratory animals with the no observed effect concentration (NOEC) for UCB = 0.4 ng/L and GC= 170 ng/L. Unexposed, control animals and animals exposed to 0.4 ng/L (GC and UCB) or 170 ng/L cyfluthrin were collected following 96-h treatments. Differences in gene expression were measured using a custom Hyalella azteca microarray. Gene expression profiles revealed that laboratory H. azteca responded to cyfluthrin through differential expression of genes involved in neurological system processes. In contract, H. azteca from Grayson Creek showed a pattern of oxidative stress through the differential expression of glutathione-S-transferases, heat shock proteins, and other genes involved in oxidation-reduction processes. Four replicate exposures consisting of ten animals were collected for each treatment or control. A one-color hybridization protocol was used so that each sample was labeled with cy3 and only one sample was hybridized to each array.
Project description:Abstract: Nanoparticles (NPs) are expected to make their way into the aquatic environment where sedimentation of particles will likely occur, putting benthic organisms at particular risk. Therefore, organisms such as Hyalella azteca, an epibenthic crustacean which forages at the sediment surface, is likely to have a high potential exposure. Here we show that Zinc Oxide (ZnO) NPs are more toxic to H. azteca compared with the corresponding metal ion, Zn2+. Dissolution of ZnO NPs contributes about 50% of the Zn measured in the ZnO NP suspensions, and cannot account for the toxicity of these particles to H. azteca. However, gene expression analysis is unable to distinguish between the ZnO NP exposures and Zinc Sulfate (ZnSO4) exposures at equitoxic concentrations. These results lead us to hypothesize that ZnO NPs provide and an enhanced exposure route for Zn2+ uptake into H. azteca, and possibly other sediment dwelling organisms. Our study supports the prediction that sediment dwelling organisms are highly susceptible to the effects of ZnO NPs and should be considered in the risk assessment of these nanomaterials. This experiment included four different treatments and an untreated control. Each treatment or control, consisted of ten independent replicates of twenty Hyalella azteca. Of these, six were randomly chosen to be used for the microarray analysis.
Project description:Abstract: Nanoparticles (NPs) are expected to make their way into the aquatic environment where sedimentation of particles will likely occur, putting benthic organisms at particular risk. Therefore, organisms such as Hyalella azteca, an epibenthic crustacean which forages at the sediment surface, is likely to have a high potential exposure. Here we show that Zinc Oxide (ZnO) NPs are more toxic to H. azteca compared with the corresponding metal ion, Zn2+. Dissolution of ZnO NPs contributes about 50% of the Zn measured in the ZnO NP suspensions, and cannot account for the toxicity of these particles to H. azteca. However, gene expression analysis is unable to distinguish between the ZnO NP exposures and Zinc Sulfate (ZnSO4) exposures at equitoxic concentrations. These results lead us to hypothesize that ZnO NPs provide and an enhanced exposure route for Zn2+ uptake into H. azteca, and possibly other sediment dwelling organisms. Our study supports the prediction that sediment dwelling organisms are highly susceptible to the effects of ZnO NPs and should be considered in the risk assessment of these nanomaterials.
Project description:Toxicity and transcriptomic analysis in Hyalella azteca suggests increased exposure and susceptibility of epibenthic organisms to Zinc Oxide Nanoparticles