Project description:Imatinib mesylate (IM) a protein kinase inhibitor drug that selectively inhibits certain oncogenic mutant protein tyrosine kinases. After application, IM is via hospital and municipal waste water effluents released into the aquatic environment, where it can harm non-target organisms. The aim of this study was to evaluate changes in gene transcription in liver of adult F1 zebrafish (Danio rerio) continuously exposed to IM at environmentaly relevant concentrations of 0.01 µg/L and 1 µg/L.
Project description:This study sought to evaluate the effects of dietary MeHg exposure on adult female yellow perch (Perca flavescens) and zebrafish (Danio rerio) reproduction by relating controlled exposures with subsequent reproductive effects. Yellow perch were used in the study for their socioeconomic and ecological importance within the Great Lakes basin, and the use of zebrafish allowed for a detailed analysis of the molecular effects of MeHg. MeHg exposures at environmentally relevant levels were done in zebrafish for a full life cycle, mimicking a realistic exposure scenario, and in adult yellow perch for twenty weeks, capturing early seasonal ovarian development. In zebrafish, several genes involved in reproductive processes were shown to be dysregulated by RNA-seq and QPCR, but no significant phenotypic or physiological changes were observed with ovarian staging, fecundity, or embryo mortality. Yellow perch did not appear to be affected by MeHg, either at a molecular level, as assessed by QPCR of eight genes in the pituitary, liver, and ovary tissue, or a physiological level, as seen with ovarian somatic index, circulating estradiol, and ovarian staging. Lack of impact in yellow perch limits the usefulness of zebrafish as a model and suggests that the reproductive sensitivity to environmentally relevant levels of MeHg differs between yellow perch and zebrafish.
Project description:Methylmercury (MeHg) is an environmental neurotoxicant known to cause adverse effects in fish, such as locomotor abnormalities, visual deficits or teratogenesis. However, very few studies have investigated the effects of environmentally realistic MeHg exposures on the gene expression of fish embryos. Since the primary source of MeHg exposure in wild fish is through the diet, this study analyzed differential gene expression in zebrafish embryos from parents that had been subjected to environmentally relevant dietary MeHg exposures (0, 1, 3, and 10ppm) throughout their whole life cycle.
Project description:Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is a broad spectrum fungicide used extensively in agricultural crops . The aim of this study is to analyse the effects of Chorothalonil on the gene expression profiles in zebrafish (Danio rerio), exposed to two concentrations of the fungicide in the water. Nominal concentrations were 1) Low 0.007mg/l (environmentally relevent) and 2) High 0.035mg/ml . A commercial third generation microarray for Danio rerio (Agielnt V3, 4x44k) was used to identify patterns of gene expression in male livers during a 96h toxicological assay.
Project description:Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) is a broad spectrum fungicide used extensively in agricultural crops . The aim of this study is to analyse the effects of Chorothalonil on the gene expression profiles in zebrafish (Danio rerio), exposed to two concentrations of the fungicide in the water. Nominal concentrations were 1) Low 0.007mg/l (environmentally relevent) and 2) High 0.035mg/ml . A commercial third generation microarray for Danio rerio (Agielnt V3, 4x44k) was used to identify patterns of gene expression in male livers during a 96h toxicological assay. Replicates: Six control, five low and four high concentrations ; 15 samples examined. Expression profiles of male livers compared. Two concentrations of the fungicide chlorothalonil were compared.
Project description:The phenylpyrazole fipronil is a widely used insecticide designed to inhibit γ -amino-butyric acid (GABA) receptors, the major inhibitory neurotransmitter in the central nervous system. Fipronil has been detected in some water systems in the ng/L range, and is reported to be neurotoxic. To address the risks associated with fipronil exposure, we measured morphological, physiological, and molecular responses in zebrafish (Danio rerio) embryos following a 48 hour exposure (20 ng/L – 2 mg/L). Survival was not different than controls following treatments below 200 µg fipronil/L but was ~20% higher with concentrations above 200 µg fipronil/L. Once the embryos hatched, they underwent a 7 day depuration phase. At 9 days post-fertilization (9 dpf), body length and notochord length were not different than controls for any dose. To assess sub-lethal effects, transcriptome profiling was conducted in 9 dpf larvae following 48 hour exposure + 7 dpf depuration to environmentally relevant concentrations of fipronil (200 ng fipronil/L), as well as two higher concentrations of the pesticide (200 µg fipronil/L and 2 mg fipronil/L). Transcriptome profiling revealed that all three concentrations affected pathways related to chromosome condensation and the metabolism of estrogens and androgens as well as genes related to methylation. In addition, 200 ng fipronil/L down-regulated genes related to the circadian clock, histone and DNA methylation, and histone acetylation, while the highest dose increased networks related to immune function (e.g. lectin-induced complement pathway and the alternative complement pathway). The two highest concentrations of fipronil increased the expression of transcriptional networks associated with mitochondrial respiratory chain dysfunction and mitochondrial protein transport. As such, we exposed 24 hpf embryos to fipronil for 24 hours and measured oxygen consumption rate to assess mitochondrial function. There were no differences in basal and maximal respiration in the embryos nor ATP production, and fipronil did not affect mitochondrial bioenergetics. This study suggests that fipronil at environmentally relevant concentrations does not adversely affect the survival or morphology of fish embryos, however sub-lethal endpoints should be examined to more fully characterize the long term effects of fipronil exposure in larval fish.