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Atrazine is an extensively used herbicide, and has become a common environmental contaminant. Effects on dopaminergic neurotransmission in mammals following exposure to atrazine have been previously demonstrated. Here, the effects of atrazine regarding behavioural and dopaminergic neurotransmission parameters were assessed in the fruit fly D. melanogaster, exposed during embryonic and larval development. Embryos (newly fertilized eggs) were exposed to two atrazine concentrations (10μM and 100μM) in the diet until the adult fly emerged. Negative geotaxis assay, as well as exploratory behaviour, immobility time and number of grooming episodes in an open field system were assessed. Tyrosine hydroxylase (TH) activity and gene expression of the dopaminergic system were also evaluated in newly emerged male and female flies. All analyzed parameters in male flies were not significantly affected by atrazine exposure. However female flies exposed to atrazine at 10μM presented an increase in immobility time and a reduction in exploratory activity in the open field test, which was offset by an increase in the number of grooming episodes. Also, female flies exposed to 100μM of atrazine presented an increase in immobility time. Gene expression of DOPA decarboxylase and dopamine (DA) receptors were also increased only in females. The behavioural effects of atrazine exposure observed in female flies were due to a disturbance in the dopaminergic system., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The herbicide atrazine has been used worldwide with subsequent residual contamination of water and food, which may cause adverse effects on non-target organisms. Animal exposure to this herbicide may affect development, reproduction and energy metabolism. Here, the effects of atrazine regarding survival and redox metabolism were assessed in the fruit fly D. melanogaster exposed during embryonic and larval development. The embryos (newly fertilized eggs) were exposed to different atrazine concentrations (10μM and 100μM) in the diet until the adult fly emerged. Pupation and emergence rates, developmental time and sex ratio were determined as well as oxidative stress parameters and gene expression of the antioxidant defence system were evaluated in newly emerged male and female flies. Atrazine exposure reduced pupation and emergence rates in fruit flies without alterations to developmental time and sex ratio. Different redox imbalance patterns were observed between males and females exposed to atrazine. Atrazine caused an increase in oxidative damage, reactive oxygen species generation and antioxidant capacity and decreased thiol-containing molecules. Further, atrazine exposure altered the mRNA expression of antioxidant genes (keap1, sod, sod2, cat, irc, gss, gclm, gclc, trxt, trxr-1 and trxr-2). Reductions in fruit fly larval and pupal viability observed here are likely consequences of the oxidative stress induced by atrazine exposure., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Glyphosate is a non-selective and post-emergent herbicide that affects plant growth. Animal exposure to this herbicide can lead to adverse effects, such as endocrine disruption, oxidative stress and behavioural disorders. Drosophilids have been utilized previously as an effective tool in toxicological tests. In the present study, the effects of a glyphosate-based herbicide (Roundup [Original]) were investigated regarding oxidative stress, the antioxidant defence system and acetylcholinesterase (AChE) activity in Drosophila melanogaster. Flies (of both genders) that were 1 to 3days old were exposed to different glyphosate concentrations (0.0g/L=control, 1.0g/L, 2.0g/L, 5.0g/L and 10.0g/L) [corrected] in the diet for 24h and 96h. After the exposure periods, reactive oxygen species (ROS) levels, antioxidant capacity against peroxyl radicals (ACAP) and lipid peroxidation (LPO) levels were quantified. In addition, the mRNA expression of antioxidant genes (i.e., keap1, sod, sod2, cat, irc, gclc, gclm, gss, trxt, trxr-1 and trxr-2) was evaluated via RT-PCR. Additionally, AChE activity was evaluated only after the 96h exposure period. The results indicated that Roundup exposure leads to a reduction in ROS levels in flies exposed for 96h. ACAP levels and gene expression of the antioxidant defence system exhibited an increase from 24h, while LPO did not show any significant alterations in both exposure periods. AChE activity was not affected following Roundup exposure. Our data suggest that Roundup exposure causes an early activation of the antioxidant defence system in D. melanogaster, and this can prevent subsequent damage caused by ROS., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Growth hormone (GH) excess causes an increment in the metabolic rate and in reactive oxygen species generation, which accelerate the ageing process in mammals. Considering that there is no information on this subject in fish, the aim of the present study was to evaluate the excess GH effect on senescence in a zebrafish (Danio rerio) transgenic model. In order to reach this objective, we analyzed the phenotype of spinal curvature and expression of genes related to the anti-oxidant defense system and myogenesis in muscle of 8 and 30 months old GH-transgenic males. Gene expression analyses revealed that both superoxide dismutase isoforms were down-regulated only in 30 months old animals, while glutamate cysteine ligase was down-regulated in GH-transgenic zebrafish. Acceleration of the spinal curvature and a reduction in the expression of miogenin at both ages and MyoD in the old fish were also observed. Although neurolipofuscin accumulation was not significant in GH-transgenic zebrafish, the estimation of maximum longevity based on the von Bertalanffy growth function was significantly lower in this group. The results obtained here indicate that GH overexpression reduces the transcription of anti-oxidant defense system and myogenesis-related genes, which probably accelerates senescence in the zebrafish transgenic model used., (2010 Elsevier Inc. All rights reserved.)

Polychaeta species like Laeonereis acuta (Nereididae) usually secrete great amounts of mucus that wrap the animal inside. Taking into account that fungi action in the sediment and UV radiation acting on dissolved organic matter in the water produces reactive oxygen species (ROS) like hydrogen peroxide (H(2)O(2)), it was considered that the mucus secretion could represent an antioxidant defense against environmental ROS. Antioxidant enzymes (catalase-CAT; superoxide dismutase-SOD; glutathione peroxidase-GPx and glutathione-S-transferase-GST) and total antioxidant capacity (TOSC) were determined in worms and mucus secretion. Higher (p<0.05) CAT, GPx and TOSC values were registered in mucus samples respect worms, SOD activity was similar (p>0.05) in both kind of samples, and absence of GST activity was observed in mucus samples, suggesting absence of catalyzed phase II reactions. In assays conducted with hepatoma cell lines exposed to H(2)O(2), it was verified that: (1) mucus co-exposure significantly (p<0.05) lowered DNA damage induced by H(2)O(2); (2) ROS production was significantly (p<0.05) reduced when cells were exposed simultaneously with mucus samples and H(2)O(2) respect H(2)O(2) alone. It can be concluded that the mucus production contributes substantially to the antioxidant defense system of the worm against environmental ROS through the interception or degradation of H(2)O(2), peroxyl and hydroxyl radicals.

The circadian rhythm of black pigment migration of melanophores of the crab Chasmagnathus granulata and the variation in responsiveness of these cells to pigment-dispersing hormone (beta-PDH), crustacean cardioactive peptide (CCAP), and red pigment-concentrating hormone (RPCH) were investigated. Melanophores of C. granulata possess an endogenous circadian rhythm of pigment migration, with black pigments staying more dispersed during the day period and more aggregated during the night period. This rhythm seems to be largely dependent on an endogenous release of neurohormones from eyestalks, and to a lesser extent on a primary response to illumination. beta-PDH was the most potent PDH isoform to induce pigment dispersion in both in vivo (EC50 = 0.4 pmol/animal) and in vitro (EC50 = 0.18 microM) assays. CCAP also induced pigment dispersion in vivo and in vitro assays (EC50 = 12 microM), but it was less potent than beta-PDH. In vivo, RPCH induced a low and nondose-dependent pigment aggregation, while in vitro, it had no effect on pigment migration. The responsiveness of melanophores of C. granulata to beta-PDH was significantly higher during the day period when compared to the night period in both assays, in vitro and in vivo. These results suggest that the endogenous circadian rhythm of black pigment migration is dependent on both endogenous circadian rhythm of beta-PDH synthesis and/or release from eyestalks and on an endogenous rhythm of responsiveness of melanophores to beta-PDH.