RESUMEN
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.
Asunto(s)
Bivalvos , Contaminantes Químicos del Agua , Animales , Glifosato , Exposición Dietética , Ecosistema , Estrés Oxidativo , Catalasa/metabolismo , Superóxido Dismutasa/metabolismo , Peroxidación de Lípido , Branquias/metabolismo , Glutatión Transferasa/metabolismo , Contaminantes Químicos del Agua/metabolismo , Biomarcadores/metabolismoRESUMEN
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 96â¯h of exposure to increasing herbicide concentrations (0, 4, 6, 8â¯mgâ¯L-1 active ingredient) with the addition of alkyl aryl polyglycol ether surfactant, the growth of the cultures decreased (96 h-IC50- 4.90â¯mgâ¯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.
Asunto(s)
Glicina/análogos & derivados , Herbicidas/toxicidad , Scenedesmus/efectos de los fármacos , Scenedesmus/metabolismo , Scenedesmus/ultraestructura , Animales , Catalasa/metabolismo , Glutatión/metabolismo , Glutatión Transferasa/metabolismo , Glicina/toxicidad , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Superóxido Dismutasa/metabolismo , Vacuolas/efectos de los fármacos , Vacuolas/metabolismo , GlifosatoRESUMEN
The aim of this study was to analyze the biochemical alterations in the golden mussel Limnoperna fortunei under dietary glyphosate exposure. Mussels were fed during 4 weeks with the green algae Scenedesmus vacuolatus previously exposed to a commercial formulation of glyphosate (6â¯mgâ¯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.
Asunto(s)
Glicina/análogos & derivados , Herbicidas/toxicidad , Mytilidae/efectos de los fármacos , Acetilcolinesterasa/metabolismo , Fosfatasa Alcalina/metabolismo , Animales , Hidrolasas de Éster Carboxílico/metabolismo , Catalasa/metabolismo , Dieta/veterinaria , Glutatión/metabolismo , Glutatión Transferasa/metabolismo , Glicina/toxicidad , Mytilidae/metabolismo , Estrés Oxidativo , Scenedesmus , Alimentos Marinos , Superóxido Dismutasa/metabolismo , Sustancias Reactivas al Ácido Tiobarbitúrico/metabolismo , GlifosatoRESUMEN
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.
Asunto(s)
Biomarcadores/metabolismo , Bivalvos/efectos de los fármacos , Glicina/análogos & derivados , Herbicidas/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Bivalvos/metabolismo , Carotenoides/metabolismo , Catalasa/metabolismo , Clorofila/metabolismo , Clorofila A , Ecosistema , Glicina/análisis , Glicina/metabolismo , Glicina/toxicidad , Semivida , Herbicidas/análisis , Herbicidas/metabolismo , Peroxidación de Lípido , Pigmentos Biológicos/análisis , Espectrofotometría Ultravioleta , Superóxido Dismutasa/metabolismo , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/metabolismo , GlifosatoRESUMEN
In this study, the impact of technical grade glyphosate acid on Limnoperna fortunei was assessed employing outdoor microcosms treated with nominal glyphosate concentrations of 1, 3 and 6 mg L(-1). At the end of the experiment (26 days), catalase (CAT), superoxide dismutase (SOD), glutathione-S-transferase (GST), acetylcholinesterase (AChE), carboxylesterases (CES) and alkaline phosphatase (ALP) activities, and lipid peroxidation levels were analyzed. GST and ALP activities and lipid peroxidation levels showed a significant increase with respect to controls in the mussels exposed to glyphosate (up to 90, 500 and 69 percent, respectively). CES and SOD activities showed a significant decrease in glyphosate exposed bivalves with respect to controls (up to 48 and 37 percent, respectively). CAT and AChE did not show differences between exposed and no exposed bivalves. The increase in lipid peroxidation levels and the decrease in SOD and CES activities observed in L. fortunei indicate that glyphosate had adverse effects on the metabolism of this bivalve. The results of the present study also indicate that a "multibiomarker approach" provides a more precise knowledge of the impact of glyphosate on L. fortunei.
Asunto(s)
Glicina/análogos & derivados , Herbicidas/toxicidad , Mytilidae/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Acetilcolinesterasa/metabolismo , Animales , Biomarcadores/metabolismo , Catalasa/metabolismo , Glutatión Transferasa/metabolismo , Glicina/toxicidad , Peroxidación de Lípido/efectos de los fármacos , Mytilidae/metabolismo , Superóxido Dismutasa/metabolismo , GlifosatoRESUMEN
Glyphosate-based formulations are among the most widely used herbicides in the world. The effect of the formulation Glifosato Atanor(®) on freshwater microbial communities (phytoplankton, bacterioplankton, periphyton and zooplankton) was assessed through a manipulative experiment using six small outdoor microcosms of small volume. Three of the microcosms were added with 3.5 mg l(-1) of glyphosate whereas the other three were left as controls without the herbicide. The treated microcosms showed a significant increase in total phosphorus, not fully explained by the glyphosate present in the Glifosato Atanor(®). Therefore, part of the phosphorus should have come from the surfactants of the formulation. The results showed significant direct and indirect effects of Glifosato Atanor(®) on the microbial communities. A single application of the herbicide caused a fast increase both in the abundance of bacterioplankton and planktonic picocyanobacteria and in chlorophyll a concentration in the water column. Although metabolic alterations related to oxidative stress were induced in the periphyton community, the herbicide favored its development, with a large contribution of filamentous algae typical of nutrient-rich systems, with shallow and calm waters. An indirect effect of the herbicide on the zooplankton was observed due to the increase in the abundance of the rotifer Lecane spp. as a consequence of the improved food availability given by picocyanobacteria and bacteria. The formulation affected directly a fraction of copepods as a target. It was concluded that the Glifosato Atanor(®) accelerates the deterioration of the water quality, especially when considering small-volume water systems.