Browsing by Author "Soares, A.M.V.M."
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- Chironomus riparius proteome responses to spinosad exposurePublication . Monteiro, Hugo R.; Pestana, João L.T.; Soares, A.M.V.M.; Devreese, Bart; Lemos, Marco F.L.The potential of proteome responses as early-warning indicators of insecticide exposure was evaluated using the non-biting midge Chironomus riparius (Meigen) as the model organism. Chironomus riparius larvae were exposed to environmentally relevant concentrations of the neurotoxic pesticide spinosad to uncover molecular events that may provide insights on the long-term individual and population level consequences. The iTRAQ labeling method was performed to quantify protein abundance changes between exposed and non-exposed organisms. Data analysis revealed a general dose-dependent decrease in the abundance of globin proteins as a result of spinosad exposure. Additionally, the downregulation of actin and a larval cuticle protein was also observed after spinosad exposure, which may be related to previously determined C. riparius life-history traits impairment and biochemical responses. Present results suggest that protein profile changes can be used as early warning biomarkers of pesticide exposure and may provide a better mechanistic interpretation of the toxic response of organisms, aiding in the assessment of the ecological effects of environmental contamination. This work also contributes to the understanding of the sublethal effects of insecticides in invertebrates and their molecular targets.
- Endocrine and physiological effects of linuron and S-metolachlor in zebrafish developing embryosPublication . Quintaneiro, C.; Patrício, D.; Novais, Sara; Soares, A.M.V.M.; Monteiro, M.S.Evaluation of the effects of linuron and S-metolachlor on apical, biochemical and transcriptional endpoints in zebrafish (Danio rerio) early life stages was the main purpose of this work. Embryos were exposed for 96h to a range of concentrations of each herbicide to determine lethal and sub-lethal effects on apical (e.g. malformations, hatching) and biochemical parameters (cholinesterase, ChE; catalase, CAT; glutathione S-transferase, GST; lipid peroxidation, LPO and lactate dehydrogenase, LDH). To evaluate endocrine disruption effects, embryos were exposed during 96h to 0.88mg/L linuron and 9.66mg/L S-metolachlor, isolated or in binary mixture. Expression of a suite of genes involved in HPT, HPG and HPA-axis was then assessed. Highest concentration of linuron (5.0mg/L) decreased hatching rate to 5% and 70.0mg/L S-metolachlor completely inhibited hatching, about 100%. Both herbicides impaired development by inducing several malformations (100% in 5.0mg/L linuron and 70.0mg/L S-metolachlor). Linuron only affected GST and CAT at concentrations of 0.25 and 0.0025mg/L, respectively. S-metolachlor induced GST (to 256%), inhibited ChE (to 61%) and LDH (to 60%) and reduced LPO levels (to 63%). Linuron isolated treatment seems to have an estrogenic mode of action due to the observed induction of vtg1. Exposure to S-metolachlor seems to interfere with steroidogenesis and with HPT and HPA-axis, since it has inhibited cyp19a2, TSHβ and CRH gene expression. In addition to vtg1 induction and CRH inhibition, herbicide combination also induced sox9b that has a role in regulation of sexual development in zebrafish. This study pointed out adverse effects of linuron and S-metolachlor, namely impairment of neurotransmission and energy production, induction of steroidogenesis, and interference with HPT and HPA-axis. These results contributed to elucidate modes of action of linuron and S-metolachlor in zebrafish embryo model. Furthermore, gene expression patterns obtained are indicative of endocrine disruption action of these herbicides.