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The placenta plays a major role in embryo-fetal defects and intrauterine growth retardation after maternal alcohol consumption. Our aims were to determine the oxidative status and cellular and molecular oxidative stress effects on uterine myometrium and trophoblast-decidual tissue following perigestational alcohol intake at early organogenesis. CF-1 female mice were administered with 10% alcohol in drinking water for 17 days prior to and up to day 10 of gestation. Control females received ethanol-free water. Treated mice had smaller implantation sites compared to controls (p < 0.05), diminished maternal vascular lumen, and irregular/discontinuous endothelium of decidual vessels. The trophoblast giant cell layer was disorganized and presented increased abnormal nuclear frequency. The myometrium of treated females had reduced nitrite content, increased superoxide dismutase activity, and reduced glutathione (GSH) content (p < 0.05). However, the trophoblast-decidual tissue of treated females had increased nitrite content (p < 0.05), increased GSH level (p < 0.001), increased thiobarbituric acid-reactive substance concentration (p < 0.001), higher 3-nitrotyrosine immunoreaction, and increased apoptotic index (p < 0.05) compared to controls. In summary, perigestational alcohol ingestion at organogenesis induced oxidative stress in the myometrium and trophoblast-decidual tissue, mainly affecting cells and macromolecules of trophoblast and decidual tissues around early organogenesis, in CF-1 mouse, and suggests that oxidative-induced abnormal early placental formation probably leads to risk of prematurity and fetal growth impairment at term.

Perigestational alcohol consumption by CF-1 mouse, from before mating up to the period of embryo organogenesis, leads to retarded early embryo development and neural tube defects. Here, we addressed if perigestational alcohol ingestion up to Day 10 of pregnancy induces oxidative stress and changes in macromolecules and organ tissues of early organogenic embryos. Adult CF-1 female mice were administered 10% ethanol in their drinking water for 17 days prior to mating and until Day 10 of gestation, whereas control females were administered ethanol-free water. Our results demonstrated significantly reduced Catalase abundance and activity and increased glutathione content in the embryos of ethanol-treated females. The nitrite level was significantly reduced, but TBARS (thiobarbituric acid reactive substances) content, an index of lipid peroxidation, did not change. Embryos derived from ethanol-treated females also showed higher abundance of 3-nitrotyrosine (3-NT)-containing proteins in all tissues, compared to the control group. Apoptosis was significantly increased in the ectoderm and mesoderm, but not in the heart-although this organ did contain more cleaved Caspase-3-positive cardiomyocytes per area of ventricular myocardium than controls. In sum, moderate perigestational alcohol ingestion up to Day 10 of gestation in mice induces oxidative stress by altering radical nitrogen species and antioxidant enzymatic and non-enzymatic mechanisms in embryos. Further, generalized protein nitration, due to unbalanced nitric oxide levels associated with tissue-specific apoptosis, was detected in embryos, suggesting that oxidative mechanisms may play an important role in the perigestational alcohol-induced malformation of organogenic embryos exposed to ethanol., (© 2017 Wiley Periodicals, Inc.)

We studied the accumulation and depuration of microcystin-LR (MCLR) in the hepatopancreas of the crab Neohelice granulata fed twice weekly with either non toxic or MCLR-producing Microcystis aeruginosa (strain NPDC1 or NPJB, respectively) during seven weeks. We also analyzed MCLR effects on the oxidative stress- and detoxification-related variables, superoxide dismutase and glutathione-S-transferase activities, and the levels of reduced glutathione and lipid peroxidation (as thiobarbituric acid reactive substances, TBARS). Hepatopancreas MCLR content slightly increased during the first three weeks, up to 8.81±1.84ngg(-1) wet tissue mass (WTM) and then started to decrease to a minimum of 1.57±0.74ngg(-1) WTM at the seventh week (p<0.05 with respect to that in the first week). TBARS levels were about 55% higher in treated than in control N. granulata (p<0.001 and p<0.05) during the first three weeks of the experimental period. GSH content became 50% lower than in control individuals (p<0.01) during weeks 6 and 7. SOD activity was increased by about 2-fold (p<0.05 or p<0.001) from week 3 to 7 in treated crabs with respect to control ones, while GST activity was about 70% higher in treated than in control crabs from week 4 to week 7 (p<0.05). Our data suggest that in the hepatopancreas of N. granulata MCLR accumulation and oxidative damage are limited and reversed by detoxification-excretion and antioxidant mechanisms. The activation of these defensive mechanisms becomes evident at 3-4 weeks after the start of the intoxication., (Copyright © 2015 Elsevier Inc. All rights reserved.)

In the present study, the effects on oxidative balance and cellular end points of glyphosate, aminomethylphosphonic acid (AMPA), and a glyphosate formulation (G formulation) were examined in HepG2 cell line, at dilution levels far below agricultural recommendations. Our results show that G formulation had toxic effects while no effects were found with acid glyphosate and AMPA treatments. Glyphosate formulation exposure produced an increase in reactive oxygen species, nitrotyrosine formation, superoxide dismutase activity, and glutathione (GSH) levels, while no effects were observed for catalase and GSH-S-transferase activities. Also, G formulation triggered caspase 3/7 activation and hence induced apoptosis pathway in this cell line. Aminomethylphosphonic acid exposure produced an increase in GSH levels while no differences were observed in other antioxidant parameters. No effects were observed when the cells were exposed to acid glyphosate. These results confirm that G formulations have adjuvants working together with the active ingredient and causing toxic effects that are not seen with acid glyphosate.

This study investigated the effects of pollution and its interaction with temperature on the oxidative status of the ribbed mussel Aulacomya atra in the southern Atlantic Patagonian coast. Animals were collected from four sites with different degree and type of human activity impact, during the summer and winter of 2011. Seawater chromium, copper, manganese, nickel and zinc concentrations were measured, as well as metal accumulation, lipid peroxidation, protein oxidation, reduced glutathione levels, and enzymatic activities of superoxide dismutase and glutathione-S-transferase in gills and digestive glands. Metal bioaccumulation and oxidative stress responses in both tissues were generally higher in mussels from harbor areas. Water temperature had a remarkable effect on gill SOD activity and protein oxidation during winter in mussels from all locations. Methodologically, we conclude that measuring both metal bioaccumulation and oxidative stress responses allowed for a more accurate assessment of the biological effects of metal present in seawater., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Oxidative stress parameter and antioxidant defense compound as well as enzyme activity were studied in relation to different Cr(VI) concentrations (0, 10, 20, 40 μM) in two strains of Euglena gracilis, one isolated from a polluted river (MAT) and the other acquired from a culture collection (UTEX). Chromium toxicity was measured in the auxotrophic and obligated heterotrophic variants of the two strains. Chromium uptake was higher in auxotrophic cultures, reflected by their higher cell proliferation inhibition and lower IC50 levels compared to heterotrophic ones. In the Cr(VI) treatments a reduction of chlorophyll a and b ratio (Chl a/Chl b) was observed, the ratio of protein to paramylon content was augmented, and total lipid content increased, having the auxotrophic strains the highest values. TBARS content increased significantly only at 40 μM Cr(VI) treatment. Unsaturated fatty acids also increased in the Cr(VI) treatments, with the higher storage lipid (saturated acids) content in the heterotrophic cells. The antioxidant response, such as SOD activity and GSH content, increased with chromium concentration, showing the highest GSH values in the heterotrophic cultures and the SOD enzyme participation in chromium toxicity. The MAT strain had higher IC50 values, higher carbohydrate and saturated acid content, and better response of the antioxidant system than the UTEX one. This strain isolated from the polluted place also showed higher GSH content and SOD activity in control cells and in almost all treated cultures. SOD activity reached a 9-fold increase in both MAT strains. These results suggest that tolerance of MAT strain against Cr(VI) stress is not only related to GSH level and/or biosynthesis capacity but is also related to the participation of the SOD antioxidant enzyme., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The toxicity of metronidazole (MTZ) in meristematic and elongation zones of Allium cepa roots was analyzed for 30 h of exposition. Toxic effects were evaluated by lipid peroxidation (content of thiobarbituric-reactive substances [TBARS]), reduced glutathione (GSH) levels, ascorbate acid and dehydroascorbate acid content, and enzymatic activities of superoxide dismutase and catalase. The root zones showed differentiated susceptibility to MTZ. In the elongation zone, MTZ induced an increase of TBARS content and a significant rise in GSH levels, whereas in the meristematic zone, lipid peroxidation was not observed and all antioxidant defense parameters analyzed were significantly increased. These results indicate that MTZ exposure induced oxidative stress in A. cepa roots, and that the antioxidant defenses in the meristematic zone are more efficient compared with the elongation zone, which is probably related to higher oxidative metabolism of meristematic tissue., (Copyright © 2012 SETAC.)

The aim of this work was to study the oxidative stress effects and histological alterations caused by dietary copper on the filter-feeding freshwater mussel Diplodon chilensis. Bivalves were fed during 6 weeks with the green algae Scenedesmus vacuolatus previously exposed to copper. Metal concentration in algae cultures and bivalve digestive gland was measured by TXRF. A maximum accumulation of 0.49 μg Cu/mg protein was detected at week 6. Also at this week, the hepatosomatic index (HSI) showed the highest decrease (50%) in response to Cu exposure. SOD and GST activities were significantly increased at weeks 4, 5 and 6, reaching an activity on average 50% higher than in controls for GST. CAT activity and GSH increased significantly at weeks 5 and 6. Despite this response, oxidative damage measured as TBARS and carbonyl groups contents increased significantly at weeks 4, 5 and 6, respectively. Digestive tubule and duct atrophy and cell-type replacement in treated mussels were observed by histological studies. The presence of intracellular rhodanine-positive granules, suggests copper accumulation in intracellular vacuoles of digestive cells., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The aim of this work was to assess the effects of 1 week copper exposure (6.2, 108, 210 and 414microM) on Scenedesmus vacuolatus and Chlorella kessleri. The strains showed different susceptibility to copper. Copper content was determined in both strains by total X-ray reflection fluorescence analysis (TXRF). In S. vacuolatus, the increase of medium copper concentration induced an augmentation of protein and MDA content, and a significant decrease in the chlorophyll a/chlorophyll b ratio. S. vacuolatus showed a significant increase of catalase activity in 210 and 414microM of copper, and a significant increment of SOD activity and GSH content only in 414microM of copper. On the contrary, C. kessleri did not show significant differences in these parameters between 6.2 and 108microM of copper. Increased copper in the environment evokes oxidative stress and an increase in the antioxidant defenses of S. vacuolatus.

Viral-induced apoptosis might be mediated by oxidative stress. It has already been described that cell death in vesicular stomatitis virus (VSV)-infected cells occurs by apoptosis. In this study, oxidative stress parameters present in VSV-infected Vero cells were analyzed. Lipid peroxides (LP) were evaluated in cellular extracts and expressed as thiobarbituric acid-reactive substances. LP levels exhibited a rise at different times post infection, according to the multiplicity of infection (MOI), while the presence of cycloheximide determined a reduction on LP. Also, an increase in protein degradation products and a decrease in polyunsaturated fatty acids content was observed, indicating that cellular proteins and lipids began to be susceptible to degradation during VSV infection. In addition, we analyzed cell viability of VSV-infected Vero cells, which were incubated in the presence of butylated hydroxyanisole. This antioxidant was able to protect Vero cells, at least at MOIs assayed in this study, and to reduce viral yield only when VSV infection was done at MOI 0.05. Further, superoxide dismutases, which occupy the first step within the antioxidant enzyme cascade, also exhibit a rise in VSV-infected Vero cells, at different MOI. These results suggest that both an oxidative stress and an antioxidative cell response precede the induction of apoptosis by VSV.

This study evaluates whether quercetin (25, 50 and 75 mg/kg body weight) treatment has a protective effect on the pro-oxidant-antioxidant state following chronic ethanol treatment in mice. Pretreatment (quercetin 25, 50 and 75 mg/kg body weight for 15 d+co-treatment of ethanol 18%+quercetin for 15 d and ethanol 18% for the 15 d) increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH) in comparison to the ethanol group. No significant differences from the ethanol group were observed in the group after post-treatment (ethanol 18% for 30 d+quercetin 25, 50 and 75 mg/kg body weight for 15 d) with quercetin. A significant increase in lipid peroxidation (malondialdehyde, MDA) products was observed in liver tissue after administration of ethanol, which was attenuated by pre- and post-treatment with a high dose of quercetin. GSH levels increased and oxidized glutathione (GSSG) levels decreased in groups of ethanol-exposed mice that received quercetin for 15 d prior to ethanol exposure. In conclusion, pre-treatment of quercetin may protect against ethanol-induced oxidative stress by directly quenching lipid peroxides and indirectly by enhancing the production of the endogenous antioxidant GSH. There was no protective effect on post-treatment with quercetin.

The aim of this study was to evaluate and compare the effects on biochemical parameters and organosomatic indices in the freshwater bivalve Diplodon chilensis exposed to a glyphosate-based formulation under direct and dietary exposures (4 mg a.p./L). After 1, 7, and 14 days of exposure, reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) levels and the activities of glutathione-S- transferase (GST), superoxide dismutase (SOD), and catalase (CAT) were evaluated in the gills and digestive gland. The hepatosomatic (HSI) and branchiosomatic (BSI) indices were also analyzed. Direct and dietary glyphosate-based formulation exposure altered the redox homeostasis in the gills and digestive gland throughout the experimental time, inducing the detoxification response (GST), the antioxidant defenses (SOD, CAT, GSH), and causing lipid peroxidation. After 14 days of exposure, the HSI and BSI increased significantly (43% and 157%, respectively) only in the bivalves under direct exposure. Greater changes in the biochemical parameters were induced by the dietary exposure than by the direct exposure. Furthermore, the gills presented an earlier response compared to the digestive gland. These results suggested that direct and dietary exposure to a glyphosate-based formulation induced oxidative stress in the gills and digestive glands of D. chilensis. Thus, the presence of glyphosate-based formulations in aquatic ecosystems could represent a risk for filter-feeding organisms like bivalves. [ABSTRACT FROM AUTHOR]

One of the most important factors regulating the distribution and abundance of seaweeds is desiccation, triggered mainly by tidal changes and climatic variation. Porphyra and Pyropia species have evolved multiple strategies to tolerate desiccation stress; however, how these tolerance strategies differ in these species inhabiting different latitudes is still unknown. In this context, we analyzed, in situ, the physiological responses of these species (collected from 18° S to 41° S along the Chilean coast) to desiccation stress using biochemical and molecular analyses. The hyper-arid terrestrial climate of northern Chile, with high evaporation and lack of constant rain determines a very steep increase in desiccation stress in the upper intertidal during low tide for these species. Accordingly, the results showed that, in comparison with the southernmost populations, the Porphyra/Pyropia species from the north zone of Chile (18°–30° S) exhibited higher contents of lipoperoxide and carbonyls (1.6–1.9 fold) together with higher enzymatic activities, including ascorbate peroxidase, catalase, peroxiredoxin, and thioredoxin (2–3-fold). In addition, a substantial expression of cat, prx, and trx transcripts during desiccation was demonstrated, mainly in the northernmost populations. These results provide evidence of (i) significant activation of antioxidant enzymes and transcripts (principally cat and prx); (ii) participation of phenolic antioxidant compounds as a highly plastic physiological strategy to cope with desiccation; and (iii) the activation of the tolerance responses was affected by species latitudinal distribution. Thus, for the first time, this study integrated the biochemical and genetic responses of diverse Porphyra/Pyropia species to better understand their physiological dynamics of tolerance over a wide latitudinal range. [ABSTRACT FROM AUTHOR]

Understanding which intracellular signaling pathways are activated by manganese stress is crucial to decipher how metal overload compromise cellular integrity. Here, we unveil a role for oxidative and cell wall stress signaling in the response to manganese stress in yeast. We find that the oxidative stress transcription factor Yap1 protects cells against manganese toxicity. Conversely, extracellular manganese addition causes a rapid decay in Yap1 protein levels. In addition, manganese stress activates the MAPKs Hog1 and Slt2 (Mpk1) and leads to an up-regulation of the Slt2 downstream transcription factor target Rlm1. Importantly, Yap1 and Slt2 are both required to protect cells from oxidative stress in mutants impaired in manganese detoxification. Under such circumstances, Slt2 activation is enhanced upon Yap1 depletion suggesting an interplay between different stress signaling nodes to optimize cellular stress responses and manganese tolerance. [ABSTRACT FROM AUTHOR]

Azoles are one of the most widely used drugs to treat fungal infections. To further understand the fungal response to azoles, we analyzed the MAPK circuitry of the model yeast Saccharomyces cerevisiae that operates under treatment with these antifungals. Imidazoles, and particularly clotrimazole, trigger deeper changes in MAPK phosphorylation than triazoles, involving a reduction in signaling through the mating pathway and the activation of the MAPKs Hog1 and Slt2 from the High-Osmolarity Glycerol (HOG) and the Cell Wall Integrity (CWI) pathways, respectively. Clotrimazole treatment leads to actin aggregation, mitochondrial alteration, and oxidative stress, which is essential not only for the activation of both MAPKs, but also for the appearance of a lowmobility form of Slt2 caused by additional phosphorylation to that occurring at the conserved TEY activation motif. Clotrimazole-induced ROS production and Slt2 phosphorylation are linked to Tpk3- mediated PKA activity. Resistance to clotrimazole depends on HOG and CWI-pathway-mediated stress responses. However, Pkc1 and other proteins acting upstream in the pathway are not critical for the activation of the Slt2 MAPK module, suggesting a novel rewiring of signaling through the CWI pathway. We further show that the strong impact of azole treatment on MAPK signaling is conserved in other yeast species. [ABSTRACT FROM AUTHOR]

Abstract The effects of a commercial glyphosate formulation on the oxidative stress parameters and morphology (including the ultrastructure) of the phytoplanktonic green microalga Scenedesmus vacuolatus were evaluated. After 96 h of exposure to increasing herbicide concentrations (0, 4, 6, 8 mg L−1 active ingredient) with the addition of alkyl aryl polyglycol ether surfactant, the growth of the cultures decreased (96 h-IC50- 4.90 mg L−1) and metabolic and morphology alterations were observed. Significant increases in cellular volume (103–353%) and dry weight (105%) and a significant decrease in pigment content (41–48%) were detected. Oxidative stress parameters were significantly affected, showing an increase in the reactive oxygen species (ROS) and reduced glutathione (GSH) contents, oxidative damage to lipids and proteins and a decrease in the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and the detoxifying enzyme glutathione-S-transferase (GST). Cells exposed to glyphosate formulation were larger and showed an increase in vacuole size, bleaching, cell wall thickening and alteration of the stacking pattern of thylakoids. The results of this study showed the participation of oxidative stress in the mechanism of toxic action of the commercial glyphosate formulation on S. vacuolatus and the relation between the biochemical, morphological and ultrastructure alterations. Highlights • Glyphosate formulation was toxic to S. vacuolatus. • Glyphosate formulation produced metabolic, morphologic and ultrastructural alterations in S. vacuolatus. • Glyphosate formulation induced oxidative stress in S. vacuolatus. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the biochemical alterations in the golden mussel Limnoperna fortune i under dietary glyphosate exposure. Mussels were fed during 4 weeks with the green algae Scenedesmus vacuolatus previously exposed to a commercial formulation of glyphosate (6 mg L −1 active principle) with the addition of alkyl aryl polyglycol ether surfactant. After 1, 7, 14, 21 and 28 days of dietary exposure, glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), acetylcholinesterase (AChE), carboxylesterases (CES) and alkaline phosphatase (ALP) activities, glutathione (GSH) content and damage to lipids and proteins levels were analyzed. A significant increase (72%) in the GST activity and a significant decrease (26%) in the CES activity in the mussels fed on glyphosate exposed algae for 28 days were observed. The ALP activity was significantly increased at 21 and 28 days of dietary exposure (48% and 72%, respectively). GSH content and CAT, SOD and AchE activities did not show any differences between the exposed and non exposed bivalves. No oxidative damage to lipids and proteins, measured as TBARS and carbonyl content respectively, was observed in response to glyphosate dietary exposure. The decrease in the CES activity and the increases in GST and ALP activities observed in L . fortunei indicate that dietary exposure to glyphosate provokes metabolic alterations, related with detoxification mechanisms. [ABSTRACT FROM AUTHOR]

As in other semelparous cephalopods,Octopus tehuelchusfemales enter a senescent state after spawning. In several taxa, damage to macromolecules that result from an imbalance between antioxidant defences and the production of reactive oxygen species (i.e. oxidative stress) has been postulated as one of the physiological costs of reproduction and one factor that contributes to ageing. In this work, we evaluate whether enzymatic and non-enzymatic antioxidant defences are conditioned by reproductive status inO. tehuelchusobtained from a wild population. The main antioxidant defences, catalase (CAT), superoxide dismutase (SOD), reduced gluthation (GSH) and lipid peroxidation (TBARS), were assessed in somatic and reproductive tissues from octopus females, at immature, mature and spent stages. Oviducal glands showed an increase in TBARS that coincides with a decrease in GSH when females reach a spent stage. No significant changes were observed in the assayed parameters on the ovary wall, digestive gland, mantle and gills along maturity stages. CAT activity was undetectable in most analysed tissues, SOD activity and GSH were similar to or lower than in other cephalopods, while average TBARS levels in somatic tissues were at least one order of magnitude higher than levels found in other molluscs. Our results show that during sexual maturation and after natural oxidative stress conditions (spawning), only oviducal glands show changes that can be linked with the physiological processes of different reproductive status. The low antioxidant defences and the flat protective reactions after spawning could be associated with the semelparous life history of this species. [ABSTRACT FROM AUTHOR]

Glyphosate is currently the most widely used herbicide in agricultural production. It generally enters aquatic ecosystems through surface water runoff and aerial drift. We evaluated the effect of glyphosate acid on biochemical parameters of periphyton exposed to concentrations of 1, 3, and 6 mg/L in outdoor mesocosms in the presence and absence of the mussel Limnoperna fortunei. Periphyton ash-free dry weight, chlorophyll a content, carotene/chlorophyll a ratio, lipid peroxidation levels, and superoxide dismutase and catalase activities were determined at days 0, 1, 7, 14, and 26 of the experimental period. Ash-free dry weight was similar between control and glyphosate-treated periphyton in the absence of L. fortunei. The latter had significantly lower carotene to chlorophyll a ratios and enzyme activities, and higher lipid peroxidation levels and chlorophyll a content than the former. These results show an adverse effect of glyphosate on the metabolism of periphyton community organisms, possibly inducing oxidative stress. On the contrary, no differences were observed in any of these variables between control and glyphosate-treated periphyton in the presence of L. fortunei. Mussels probably attenuated the herbicide effects by contributing to glyphosate dissipation. The results also demonstrate that biochemical markers provide useful information that may warn of herbicide impact on periphyton communities. Environ Toxicol Chem 2017;36:1775-1784. © 2016 SETAC [ABSTRACT FROM AUTHOR]

In the present study, the influence of the spray adjuvant on the toxicity effects of a glyphosate formulation was examined in HEp-2 cell line. We determined the median lethal concentration (LC50) of Atanor® (glyphosate formulation), Impacto® (spray adjuvant) and the mixture of both agrochemicals. We also compared the toxicities of the pesticides individually and in mixture and we analyzed the effects on oxidative balance from each treatment. Our results showed that all the agrochemicals assayed induce dose and time-dependent cytotoxicity and that the toxicity of Impacto® with Atanor® (mixture) was additive on HEp-2 cell line. All the agrochemicals assayed produced an increase in catalase activity and glutathione levels, while no effects were observed for superoxide dismutase and glutathione-S-transferase activities. We found an important increase in ROS production in cells treated with Atanor® and mixture. Besides, all the agrochemicals used triggered caspase 3/7 activation and hence induced apoptosis pathway in this cell line. In conclusion, our results demonstrated that the addition of adjuvant to glyphosate formulation increase the toxicity of the mixture in cell culture. Furthermore, cell culture exposed to agrochemical mixture showed an increased ROS production and antioxidant defenses. [ABSTRACT FROM AUTHOR]

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Highlights: [•] Anthropogenic input in D. chilensis food could be traced using specific FA. [•] FA markers showed higher terrestrial detritus and bacteria in SMA sediment and bivalves. [•] Increased lipid peroxidation and lipofuscin levels (20 fold) were observed in SMA. [•] Chronic exposure of Diplodon chilensis to sewage discharges affected its lipid and FA composition. [ABSTRACT FROM AUTHOR]

Abstract: The effect of chronic exposure to Escherichia coli on morphometrical parameters, different antioxidant defenses, lipid peroxidation and protein oxidation has been studied in digestive gland of the freshwater mussel Diplodon chilensis in the laboratory during 6 weeks. In, a parallel field study, we evaluated morphometrical and oxidative stress parameters in digestive glands of mussels collected from a sewage polluted area (SMA) and from a pristine area (control). Both sites were characterized by analyzing bacteriological and physic-chemical parameters. In the laboratory D. chilensis was able to filter bacteria at high concentrations with a clearing rate of 0.510±0.036L/h per gram of dry soft tissue mass. The digestive gland mass to shell length ratio (DGM/SL), reduced glutathione (GSH), lipid peroxidation, as concentration of thiobartituric acid reactive substances (TBARS), and glutathione-S-transferase (GST) activity of mussels fed with bacteria were significantly higher than those of control mussels after the fourth week. Fecal bacteria in lake water samples were undetectable in the control, and higher than 24,000MPN (most probable number)/100mL in SMA. DGM/SL was higher in SMA. No differences between sites were observed in total lipid and protein content, neither in superoxide dismutase activity. GSH content was higher in SMA, with no difference in the oxidized form. GST activity and MDA were significantly higher in SMA but protein oxidation was not affected. [Copyright &y& Elsevier]

We studied the toxicity of a glyphosate formulation and provide evidence of metabolic alterations due to oxidative stress caused in a Chlorella kessleri tolerant strain by exposure to the herbicide. After 96h of exposure to increasing concentrations of the herbicide (0–70mgL−1) with alkylaryl polyglycol ether surfactant, growth was inhibited (EC50-96h 55.62mgL−1). Glyphosate increased protein and malondialdehyde content which was significantly higher than in the control at 50–70mgL−1. Superoxide dismutase and catalase activities and reduced glutathione levels increased in a concentration-dependant manner. Morphological studies showed increases in vacuolisation and in cell and sporangia sizes. The glyphosate formulation studied has a cytotoxic effect on C. kessleri through a mechanism that would involve the induction of oxidative stress. Upon glyphosate exposure, oxidative stress parameters such as SOD and CAT activities and MDA level could be more sensitive biomarkers than usually tested growth parameters in C. kessleri. [Copyright &y& Elsevier]

We have already demonstrated that a combined treatment of methimazole and an antioxidant mixture improved the condition of hyperthyroid patients both biochemically and clinically. Elevated thyroid hormone levels might trigger signs and symptoms of hyperthyroidism through the increase of free radicals. To study the direct effect of thyroid hormone on cellular markers of oxidative stress, we carried out in vitro assays in which 0.1–20.0 nM T3 (6.5–1300.0 ng/dl) doses were added to culture media of the human hepatocyte cell line Hep G2 for 1–24 h. T3 increased malondialdehyde (MDA) and intracellular oxidized glutathione (GSSG) levels; SOD activity was also higher with hormone treatment, whereas catalase and glutathione peroxidase activities showed no variation at different T3 doses and during all experimental times. When ascorbic acid was added to the culture, the MDA level decreased and SOD activity was increased. With higher doses of T3 (e.g. 200 nM), cell death occurred (69% of apoptotic cells). The increase in SOD activity was not enough to overcome the effect of T3 since MDA and GSSG remained high during a 24-h experiment. We showed a beneficial effect of ascorbic acid when cells were exposed to a T3 dose of 20 nM, a higher level of hormone than that achieved in hyperthyroidism. [ABSTRACT FROM AUTHOR]

Glutaredoxins are thiol oxidoreductases that regulate protein redox state. In Saccharomyces cerevisiae, Grx1 and Grx2 are cytosolic dithiol glutaredoxins, whereas Grx3, Grx4, and Grx5 are monothiol glutaredoxins. Grx5 locates at the mitochondrial matrix and is needed for iron/sulfur cluster biogenesis. Its absence causes phenotypes such as inactivation of iron/sulfur enzymes and sensitivity to oxidative stress. Whereas Grx5 contains a single glutaredoxin domain, in Grx3 and Grx4 a thioredoxin-like domain is fused to the glutaredoxin domain. Here we have shown that Grx3 locates at the nucleus and that the thioredoxin-like domain is required for such location. We have addressed the functional divergence among glutaredoxins by targeting Grx2/3/4 molecules to the mitochondrial matrix using the Grx5 targeting sequence. The mitochondrial forms of Grx3 and Grx4 partially rescue the defects of a grx5 null mutant. On the contrary, mitochondrially targeted Grx2 does not suppress the mutant phenotype. Both the thioredoxin-like and glutaredoxin domains are needed for the mitochondrial activity of Grx3, although none of the cysteine residues at the thioredoxin-like domain is required for rescue of the grx5 phenotypes. We have concluded that dithiol glutaredoxins are functionally divergent from monothiol ones, but the latter can interchange their biological activities when compartment barriers are surpassed. [ABSTRACT FROM AUTHOR]

The Paraná River basin is one of the most important in South America and is affected by human activities that take place on its margins. In particular, the De la Cruz stream flows through an industrial pole and the Arrecifes River goes mainly through agricultural fields. The aim of this study was to evaluate the water quality of the De la Cruz stream (S1) and the Arrecifes River (S2) by means of physicochemical parameters, including metals and pesticides concentrations. Since amphibians are good indicators of environmental quality, bioassays with Rhinella arenarum were carried on. For lethal and sublethal parameters, embryos and larvae were exposed to a dilution gradient of water samples and AMPHITOX Solution (AS) as negative control for 504 h. For the determination of oxidative stress biomarkers (Catalase -CAT-, Glutathione S-Transferase -GST-, Reduced Glutathione -GSH-, and lipid peroxidation -TBARS-), embryos and larvae were exposed to undiluted water samples and AS. For the determination of micronuclei, larvae at hind limb bud stage (S.28) were exposed to undiluted water samples, simultaneously with negative and positive controls (AS and cyclophosphamide 40 mg/L, respectively). Dissolved oxygen was low in both sites and the copper levels exceeded the Argentine limit for the protection of aquatic life. In embryos exposure, water sample from S1 caused lethal effects (504h-LC50 = 49 (28–71.6)%), increased TBARS levels, and GST and CAT activities. In larvae exposure, water sample from this site decreased CAT activity, while the water sample from S2 caused important lethal effects (504h-LC50 = 98.72 (60.60–302.52)%), low GSH levels and increased GST activity. Water samples from both sites induced higher micronuclei frequency than the negative control. This study alerts about the degradation of water quality of the studied sites including lethal and sublethal effects in R. arenarum that can jeopardize the native populations of this species. Image 1 • Glyphosate, AMPA and permethrine were detected in the water samples. • Metals in high concentrations were found in both water samples. • Lethal effects on the exposed organisms to both water samples were observed. • Water samples from both sites altered the oxidative stress biomarkers measured. • Larvae exposed to both water samples presented a high micronuclei frequency. Water samples from the De la Cruz stream and the Arrecifes River caused lethal and sublethal effects on the embryos and larvae of Rhinella arenarum. [ABSTRACT FROM AUTHOR]

Mitogen-activated protein kinases (MAPKs) are key mediators of signaling in fungi, participating in the response to diverse stresses and in developmental processes. Since the precise regulation of MAPKs is fundamental for cell physiology, fungi bear dual specificity phosphatases (DUSPs) that act as MAP kinase phosphatases (MKPs). Whereas fungal MKPs share characteristic domains of this phosphatase subfamily, they also have specific interaction motifs and particular activation mechanisms, which, for example, allow some yeast MKPs, such as Saccharomyces cerevisiae Sdp1, to couple oxidative stress with substrate recognition. Model yeasts show that MKPs play a key role in the modulation of MAPK signaling flow. Mutants affected in S. cerevisiae Msg5 or in Schizosaccharomyces pombe Pmp1 display MAPK hyperactivation and specific phenotypes. MKPs from virulent fungi, such as Candida albicans Cpp1, Fusarium graminearum Msg5, and Pyricularia oryzae Pmp1, are relevant for pathogenicity. Apart from transcriptional regulation, MKPs can be post-transcriptionally regulated by RNA-binding proteins such as Rnc1, which stabilizes the S. pombePMP1 mRNA. P. oryzae Pmp1 activity and S. cerevisiae Msg5 stability are regulated by phosphorylation and ubiquitination, respectively. Therefore, fungi offer a platform to gain insight into the regulatory mechanisms that control MKPs. [ABSTRACT FROM AUTHOR]

The final effect of pesticides and their mixtures on living organisms is determined by the particular toxicodynamics of the system. Oxidative stress is one of the most studied molecular mechanisms of toxicity due to increasing evidence supporting its association with the toxic effects of different agrochemicals. In the present study we evaluated the presence of redox balance alterations in the cell lines HEp-2 and A549 exposed to formulations of glyphosate (March®) and cypermethrin (Superfina®) used separately or in combination (in a proportion equivalent to that used in soybean fields). We determined the activity of catalase, superoxide dismutase, glutathione S-transferase, intracellular GSH content, content of oxidized proteins (as measure of damage) and intracellular ROS content in both cell lines at two different mixture concentrations. Additionally, we evaluated the presence of statistical interaction to determine if the effect of the mixture on the parameters evaluated was additive, synergistic, or antagonistic. For this purpose, we used the Combination Subthresholding, Cooperative Effect and Statistical Linear Interaction approaches. We found that the interaction between pesticides depended on their concentration and the cellular models studied. • Interactions between pesticides on living organisms depended on the concentration. • The interaction between glyphosate and cypermethrin induce oxidative stress. • Effect of pesticides and mixtures is determined by the toxicodynamics of each system. • Interactions between pesticides depends on cell type used in the analysis. [ABSTRACT FROM AUTHOR]

The Saccharomyces cerevisiae cell wall integrity (CWI) pathway took this name when its role in the cell response to cell wall aggressions was clearly established. The receptors involved in sensing the damage, the relevant components operating in signaling to the MAPK Slt2, the transcription factors activated by this MAPK, as well as some key regulatory mechanisms have been identified and characterized along almost 30 years. However, other stimuli that do not alter specifically the yeast cell wall, including protein unfolding, low or high pH, or plasma membrane, oxidative and genotoxic stresses, have been also found to trigger the activation of this pathway. In this review, we compile almost forty non-cell wall-specific compounds or conditions, such as tunicamycin, hypo-osmotic shock, diamide, hydroxyurea, arsenate, and rapamycin, which induce these stresses. Relevant aspects of the CWI-mediated signaling in the response to these non-conventional pathway activators are discussed. The data presented here highlight the central and key position of the CWI pathway in the safeguard of yeast cells to a wide variety of external aggressions. [ABSTRACT FROM AUTHOR]

Abstract: We analyzed the dietary copper effects in the estuarine crab Neohelice (Chasmagnathus) granulata and its interaction with water salinity. Crabs were maintained at 2‰ and 30‰ salinity for 5 weeks and they were fed with commercial food supplemented with the green alga Scenedesmus vacuolatus previously exposed to copper. No mortalities were observed, but crabs maintained at 2‰ salinity accumulated on average 40% more copper compared to animals maintained at 30‰ salinity. At 2‰ salinity, superoxide dismutase (SOD) activity and reduced glutathione (GSH) levels were increased at the first and second weeks, respectively, while lipid peroxidation and protein oxidation were evident after 4 weeks of copper exposure. At 30‰ salinity, all measured variables increased progressively but were significantly higher only at the end of the assay (5th week), except for protein oxidation that remained unchanged throughout the experiment. The hepatosomatic index (HSI) was significantly decreased in response to copper exposure, but only in crabs acclimated to 2‰. These findings have suggested that dietary copper exposure induces greater metal accumulation and larger oxidative stress responses in crabs maintained at 2‰ salinity. [Copyright &y& Elsevier]

Abstract: The aim of this work was to study the transference of hexachlorobenzene from a green alga (Chlorella kessleri) to an estuary crab (Chasmagnathus granulatus), and to analyze the toxic effects that the xenobiotic has on the latter. The effect of hexachlorobenzene uptake was evaluated measuring oxidative stress, Uroporphyrinogen decarboxylase activity and morphometric parameter alteration, and also performing a histological analysis of crab hepatopancreas. Results demonstrated that hexachlorobenzene enters the alga, is accumulated in it, and then transferred into the crab, causing a decrease in Uroporphyrinogen decarboxylase activity in both organisms. The high malondialdehyde levels detected in crab hepatopancreas after the toxic treatment suggested the existence of hexachlorobenzene-induced lipid peroxidation. Antioxidant defenses such as superoxide dismutase activity and reduced glutathione content fell below normal values on the fourth week of treatment. At the same time, the hepatosomatic index, used as a morphometric parameter, reduced 20% with respect to the control. The histological analysis revealed epithelium disorganization in hepatopancreas tubules, confirming the existence of structural damage caused by hexachlorobenzene. [Copyright &y& Elsevier]