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The aim of this study was to evaluate the acute lethality and chronic sublethal effects of lithium (Li) on Rhinella arenarum tadpoles as model organisms. First a 96 h toxicity assay was performed by exposing tadpoles to Li concentrations from 44.08 to 412.5 mg L-1 to estimate the mortality, and lethal and sublethal effects. Another bioassay was carried out by exposing tadpoles to two environmentally relevant Li concentrations (2.5 and 20 mg L-1) for one and two weeks. The sublethal effects of Li on tadpoles were evaluated by analyzing biochemical, genotoxic, and physiological biomarkers. The mortality in Li-exposed tadpoles increased over time. The median lethal concentration (LC50) ranged from 319.52 (281.21-363.05) mg L-1 at 48 h to 66.92 (52.76-84.89) mg L-1 at 96 h. Exposure to Li at 2.5 and 20 mg L-1 induced alterations in enzymes related to detoxification, antioxidant, and hepatic mechanisms, endocrine disruption of thyroid hormones, genotoxicity, and effects on the physiology of the heart and gastrointestinal systems. Tadpoles exposed to the highest concentration in the chronic bioassay (20 mg L-1 Li), which is the concentration commonly recorded in Li mining sites, showed significant mortality after one week of exposure. These results warn about the high ecotoxicological risk of Li as a contaminant of emerging concern for amphibians.
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The aim of this study was to characterize an aquatic system of Santa Fe province (Argentina) receiving wastewater from agro-industrial activities (mainly dairy) by in situ assessment (fauna mortality, physicochemical, microbiological, and pesticide residues measurement), and ecotoxicity bioassays on amphibian tadpoles. Water and sediment samples were obtained from the Los Troncos Stream (LTS), previous to the confluence with the "San Carlos" drainage channel (SCC), and from the SCC. Biological parameters (mortality and sublethal biomarkers) were used to evaluate ecotoxicity during 10-day exposure of Rhinella arenarum tadpoles to LTS and SCC samples. Nine pesticides were detected in both LTS and SCC. Chemical and biochemical oxygen demand, ammonia, and coliform count recorded in SCC greatly exceeded limits for aquatic life protection. At SCC and LTS after the confluence with SCC, numerous dying and dead aquatic turtles (Phrynops hilarii) were recorded. In the ecotoxicity assessment, no mortality of tadpoles was observed in LTS treatment, whereas total mortality (100%) was observed in SCC treatments in dilution higher than 50% of water and sediment. For SCC, median lethal concentration and the 95% confidence limits was 18.30% (14.71-22.77) at 24 h; lowest-observed and no-observed effect concentrations were 12.5% and 6.25%, respectively. Oxidative stress and neurotoxicity were observed in tadpoles exposed to 25% SCC dilution treatment. In addition, there was a large genotoxic effect (micronuclei test) in all sublethal SCC dilution treatments (6.25%, 12.5%, and 25%). These results alert about the high environmental quality deterioration and high ecotoxicity for aquatic fauna of aquatic ecosystems affected by agro-industrial wastewater. PRACTITIONER POINTS: Great mortality of turtles was observed in a basin with a high load of agro-industrial wastewater. San Carlos Channel (SCC), where effluents are spilled, is environmentally deteriorated. The water-sediment matrix of SCC caused 100% lethality in tadpoles. SCC dilutions caused neurotoxicity, oxidative stress, and genotoxicity on tadpoles.
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Tartarugas , Animais , Biomarcadores Ambientais , Águas Residuárias , Ecossistema , Rios , Anfíbios , Saúde Ambiental , Água , América do SulRESUMO
The biochemical effects of sublethal exposure to polyethylene microplastics (PEM) of 40-48 µm particle size and the flame retardant tetrabromobisphenol A (TBBPA), a plastic additive, on the freshwater shrimp Palaemonetes argentinus were assessed. Here, we postulate that the use of enzyme and thyroid hormones as biomarkers contributes to the knowledge of the effects of microplastics and plastic additives on freshwater crustaceans. To address this, we evaluated the activities of acetylcholinesterase (AChE), glutathione S-transferase (GST), and carboxilesterase (CbE, using 1-naphthyl acetate (NA) as substrate) and levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) after shrimp were exposed (for 96 h) to these xenobiotics at environmentally realistic concentrations. The results showed that the mixture of both xenobiotics led to a decrease in AChE and GST activities and increased T4 levels. We suggest that physiological processes could be compromised in freshwater organisms when exposed to microplastics and TBBPA together, and this could ultimately affect upper levels of the food web.
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Muscle and viscera (gills-liver) of the fish Prochilodus lineatus were obtained from four sites of lower course of Salado river and one site at Santa Fe river near to its confluence with Salado river from Santa Fe (Argentina) between December 2021 and February 2022. Sediment samples were also obtained from the same sites. All samples were analyzed for pesticide residues following the QuEChERS method to quantify 136 compounds by UHPLC-ESI-MS/MS and GC-EI-MS/MS. Overall, muscle fish tissue showed very high concentrations (maximum concentrations detected) of the insecticide cypermethrin (204 µg/kg), polar herbicides (glyphosate; 187 µg/kg and its degradation product (aminomethylphosphonic acid) AMPA; 3116 µg/kg, and glufosinate-ammonium; 677 µg/kg), and the fungicide pyraclostrobin (50 µg/kg). In viscera samples, high values of cypermethrin (506 µg/kg), chlorpyrifos (78 µg/kg), and lambdacyhalothrin (73 µg/kg) were the main pesticides found. Mean residues concentrations detected among sites were not significantly different neither in muscle nor viscera of P. lineatus in most of the cases. Exceptionally, the southernmost studied site of the Lower Salado river showed significant differences in concentration of residues found in muscle, due to high concentrations of glyphosate and glufosinate-amonium (KW = 11.879 and KW = 13.013, respectively, P < 0.05). Other norther Lower Salado river site showed significant higher AMPA concentration in fish viscera than in the rest of the studied sites (KW = 12.86 P < 0.05). Some sediment samples showed low levels of herbicides such as glyphosate (24 µg/kg) and fungicides. However, the world highest levels of polar herbicides were recorded in fish muscle. The results of this study highlight the need for periodic monitoring due to the high concentration of pesticides and its potential risk in a very important commercial freshwater fish from Argentina, which is consumed locally and exported to other countries for human consumption.
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Caraciformes , Herbicidas , Resíduos de Praguicidas , Praguicidas , Poluentes Químicos da Água , Animais , Humanos , Resíduos de Praguicidas/análise , Herbicidas/análise , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/análise , Espectrometria de Massas em Tandem , Monitoramento Ambiental/métodos , Poluentes Químicos da Água/análise , América do SulRESUMO
Microplastics (MPs) are critical emerging pollutants around the world. There is a growing interest in the effects of MP ingestion, non-digestion, and toxicity on aquatic organisms. Amphibian tadpoles are the vertebrate group that has received the least attention regarding this issue. The aim of the present study was to determine the ingestion of polyethylene MPs by Scinax squalirostris tadpoles by atomic force microscopy (AFM) and to evaluate the activities of carboxylesterase (CbE, using 4-naphthyl butyrate-NB-, and 1-naphthyl acetate -NA- as substrates) and alkaline phosphatase (ALP) under MP exposure. Enzyme activities were analyzed spectrophotometrically at 2 and 10 days of exposure. Tadpoles were exposed to two different treatments during 10 days: a negative control (CO, dechlorinated water) and MP (60 mg L-1). AFM images of the digestive contents of tadpoles revealed the presence of MPs. After 10 days of MP exposure, CbE (NB) activity was significantly higher and CbE (NA) activity was significantly lower in MP treatments than in controls. ALP activity decreased in MP treatments after 2 and 10 days of exposure. The detection of MP particles in the intestinal contents and the effects on metabolic enzymes in a common frog species evidenced the potential health risk of MP to aquatic vertebrates. Thus, the differential response in enzymes and substrates demonstrate the need for considering the complex effects of contaminants and nutrients on ecosystems for ecotoxicological risk characterization.
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Microplásticos , Poluentes Químicos da Água , Animais , Anuros , Carboxilesterase/farmacologia , Ecossistema , Monitoramento Ambiental , Larva , Monoéster Fosfórico Hidrolases/farmacologia , Plásticos , Poluentes Químicos da Água/toxicidadeRESUMO
The aim of the present study was to evaluate the response in larvae of the anuran species Rhinella arenarum, Rhinella dorbignyi and Odontophrynus americanus exposed to glyphosate (GLY, 2.5 mg L-1), cypermethrin (CYP, 0.013 mg L-1), chlorpyrifos (CP, 0.1 mg L-1) and glufosinate-ammonium (GLU, 15 mg L-1) using two behavioral endpoints: mean speed (MS) and total distance moved (TD); and two enzymatic biomarkers: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). In order to assess a global response and to determine the most sensitive species, an integrated biomarker response (IBR) index was calculated. Behavioral biomarkers were tested at 1 and 60 min, and the enzymes at 60 min after exposure. The results showed that: (1) there were statistical differences between species in a series of responses in swimming behavior, and cholinesterase activities within the first-hour of exposure to CYP, GLY, and CP at environmentally relevant concentrations (ERC); (2) IBR determined that Rhinella species were the most sensitive of the species tested and (3) IBR provided a comprehensive assessment of the health status of species exposed to ERC of a wide variety of agrochemicals globally and frequently used.
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Clorpirifos , Poluentes Químicos da Água , Acetilcolinesterase , Agroquímicos , Aminobutiratos , Animais , Anuros , Biomarcadores , Bufonidae , Butirilcolinesterase , Clorpirifos/toxicidade , Glicina/análogos & derivados , Larva , Piretrinas , GlifosatoRESUMO
This study increases our understanding of how diet-driven phenotypic plasticity can help non-target aquatic invertebrates deal with chlorpyrifos (CPO) exposure. A bioassay was performed over 6 days with the freshwater shrimp Macrobrachium borellii. Experimental treatments included CPO-treated shrimps (10 µg L-1) were fed with (i) a lipid-rich diet, (ii) a lipid-medium diet, or (iii) a lipid-poor diet. Control shrimps (no CPO exposure) received the same diets as detailed above. Cholinesterases and carboxylesterases were determined as an indicator of CPO exposure. Results showed that diets with a medium-to-high lipid content were important inducers of esterase activity, while shrimps exposed to CPO under a lipid-poor diet showed a significant enzymatic inhibition. This diet-dependent esterase induction suggests that the intake of fatty dietary items mitigates the esterase enzyme inhibition caused by CPO exposure.
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Clorpirifos , Palaemonidae , Animais , Dieta , Gorduras na Dieta , Água DoceRESUMO
Dexamethasone (DEX) is a glucocorticoid highly effective as an anti-inflammatory, immunosuppressant and decongestant drug. In the present study, a preliminary acute toxicity test was assayed in order to determinate DEX median-lethal, lowest-observed-effect and the no-observed-effect concentrations (LC50, LOEC and NOEC, respectively) on the common toad embryos (Rhinella arenarum). Also, morphological and histological abnormalities from five body larval regions, liver melanomacrophages (MM) and glutathione S-transferase (GST) activity were evaluated in the toad larvae to characterize the chronic sublethal effects of DEX (1-1,000 µg L-L). Results of the acute test showed that the LC50 of DEX at 96 h of exposure for the toad embryos (GS 18-20) was 10.720 mg L-g, and the LOEC was 1 µg L-g. In the chronic assay, the larval development and body length were significantly affected. DEX exposition also induced teratogenic effects. Most frequent external abnormalities observed in DEX-treated larvae included abdominal edema and swollen body, abnormal gut coiling and visceral congestion. Intestinal dysplasia was recurrent in cross-section of all DEX-treated larvae. Neural, conjunctive and renal epithelial cells were also affected. Significant increase in liver MM number and size, and GST activity levels were also registered in DEX treatments with respect to controls. The evaluation of a variety of biomarkers provided clear evidence of toad larvae sensitivity to DEX, and the ecotoxicological risk of these pharmaceuticals, commonly found in different water bodies worldwide on aquatic animals.
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Anormalidades Induzidas por Medicamentos/veterinária , Bufo arenarum/crescimento & desenvolvimento , Dexametasona/toxicidade , Glucocorticoides/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Ecotoxicologia , Embrião não Mamífero/anormalidades , Embrião não Mamífero/efeitos dos fármacos , Larva/efeitos dos fármacos , Dose Letal MedianaRESUMO
Introduction: Recognition of the variety of ecosystem services that biodiversity performs in agroecosystems is one of the basic principles of agroecology. Because indices of functional diversity may be directly related with ecosystem services, an assessment of functional diversity can be useful for evaluating ecosystem services provided under agroecological management. Objective: We compared functional diversity of birds found in rice fields under conventional and agroecological management in the rice zone of Santa Fe Province, Argentina. Our objective was to determine whether agroecological management of rice is associated with a higher functional diversity and a different functional composition of birds than conventional management. Methods: We surveyed birds eight times, roughly every 15 days between November 2017 and March 2018, from beginning of sowing to before harvest, in both types of rice fields. Birds were sampled by a combined technique of line transects and point counts at four sites in each type of management. We calculated indices of functional diversity and composition based on morphologic and trophic attributes of birds detected in each type of field. Results: Functional richness, divergence and dispersion were higher under agroecological management. Only differences in functional richness between managements reflected differences in species richness. Community-level weighted means of trait values by sample varied between management types. An insectivorous diet, pursuit as a foraging method, and air and shrubs as foraging substrates were traits best represented under agroecological management. Conclusions: Our results suggest that agroecological management of rice crops is related with a higher functional diversity of birds than conventional practices, suggesting that agroecological management may enhance the provision of ecosystem services by birds in rice agroecosystems.
Introducción: El reconocimiento de la variedad de servicios ecosistémicos de la biodiversidad en los agroecosistemas es uno de los principios básicos de la agroecología. Debido a que los índices de diversidad funcional pueden estar directamente relacionados con los servicios ecosistémicos, la evaluación de la diversidad funcional representa una estrategia adecuada para evaluar estos servicios en agroecosistemas bajo manejo agroecológico. Objetivo: Se comparó la diversidad funcional de aves entre arroceras bajo manejo convencional y agroecológico en la zona arrocera de la provincia de Santa Fe, Argentina. El objetivo fue determinar si el manejo agroecológico del arroz se asocia con una mayor diversidad funcional y con una diferente composición funcional de aves en relación con el manejo convencional. Métodos: Se muestrearon las aves mediante 8 conteos repetidos aproximadamente cada 15 días entre noviembre 2017 y marzo 2018, desde el comienzo de la siembra hasta antes de la cosecha, en ambos tipos de arroceras. Los muestreos fueron realizados mediante una técnica mixta combinando transectas de línea y puntos de conteo en cuatro sitios por tipo de manejo. Se calcularon índices de diversidad y composición funcional con base en atributos morfológicos y tróficos de las aves registradas. Resultados: La riqueza, la divergencia y la dispersión funcional fueron más altos bajo manejo agroecológico. Solamente en el caso de la riqueza funcional las diferencias reflejaron únicamente la variación de la riqueza de especies. La media ponderada a nivel de ensamble de los valores de los rasgos por muestra varió entre los tipos de manejo, estando la dieta insectívora, la persecución como método de forrajeo, y el aire y los arbustos como sustrato de forrajeo mejor representados bajo manejo agroecológico. Conclusión: Los resultados sugirieron que el manejo agroecológico del arroz se relaciona con una mayor diversidad funcional de aves que las prácticas de manejo convencional, sugiriendo que el manejo agroecológico puede mejorar la provisión de servicios ecosistémicos por aves en cultivos de arroz.
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Oryza/crescimento & desenvolvimento , Ecossistema , Argentina , Aves , Agricultura SustentávelRESUMO
Dimethoate (D) are among the most commonly used organophosphates insecticides in the world. To evaluate the toxicity of two D formulations were selected as test organisms tadpoles of Rhinella arenarum. This toad species has an extensive neotropical distribution and is easy to handle and acclimate to laboratory conditions. The tadpoles were exposed in an acute assay for 48 h to D soluble concentrates (DSC) and emulsifiable concentrates (DEC). The 48 h-LC50 (95% confidence limits) value of DSC was 57.46 mg L-1 (40.52-81.43) and to DEC was 12.76 mg L-1 (10.39-15.68). These differences in toxicity were statistically significant (p < 0.05). In both formulations, acetylcholinesterase), carboxylesterase, and glutathione-S-transferases enzyme activities varied significantly respect to those of control group (p < 0.05). The DEC formulation was the most toxic. These results would allow the assessment and characterization of potential ecological risks following the application of those formulations.
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Bufo arenarum , Dimetoato/toxicidade , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Animais , Dimetoato/química , Inseticidas/química , Larva/enzimologia , Dose Letal Mediana , Testes de Toxicidade , Poluentes Químicos da Água/químicaRESUMO
The toxicity of glyphosate-based herbicide (GBH) and arsenite (As(III)) as individual toxicants and in mixture (50:50 v/v, GBH-As(III)) was determined in Rhinella arenarum tadpoles during acute (48 h) and chronic assays (22 days). In both types of assays, the levels of enzymatic activity [Acetylcholinesterase (AChE), Carboxylesterase (CbE), and Glutathione S-transferase (GST)] and the levels of thyroid hormones (triiodothyronine; T3 and thyroxine; T4) were examined. Additionally, the mitotic index (MI) of red blood cells (RBCs) and DNA damage index were calculated for the chronic assay. The results showed that the LC50 values at 48 h were 45.95 mg/L for GBH, 37.32 mg/L for As(III), and 30.31 mg/L for GBH-As(III) (with similar NOEC = 10 mg/L and LOEC = 20 mg/L between the three treatments). In the acute assay, Marking's additive index (S = 2.72) indicated synergistic toxicity for GBH-As(III). In larvae treated with GBH and As(III) at the NOEC-48h (10 mg/L), AChE activity increased by 36.25% and 33.05% respectively, CbE activity increased by 22.25% and 39.05 % respectively, and GST activity increased by 46.75% with the individual treatment with GBH and by 131.65 % with the GBH-As(III) mixture. Larvae exposed to the GBH-As(III) mixture also showed increased levels of T4 (25.67 %). In the chronic assay at NOEC-48h/8 (1.25 mg/L), As(III) and GBH-As(III) inhibited AChE activity (by 39.46 % and 35.65%, respectively), but did not alter CbE activity. In addition, As(III) highly increased (93.7 %) GST activity. GBH-As(III) increased T3 (97.34%) and T4 (540.93%) levels. Finally, GBH-As(III) increased the MI of RBCs and DNA damage. This study demonstrated strong synergistic toxicity of the GBH-As(III) mixture, negatively altering antioxidant systems and thyroid hormone levels, with consequences on RBC proliferation and DNA damage in treated R. arenarum tadpoles.
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Alzheimer's disease (AD) is the most common cause of dementia, characterized by loss of selective neuronal and normal brain functions. Every year, ten million new cases are diagnosed worldwide. AD is a complex disease associated with all kind of different pathways, making their simultaneous modulation necessary. Nowadays anti-AD treatments are focused on enzymatic inhibitors. The study of the amphibians' skin had acquired great importance in the fields of biology and human health and represents an attractive and novel source for natural compounds with high potential in the development of new drugs. The present work exhibits the power of amphibian skins as a source of bioactive compounds. Herein we report the activity of extracts of two species from Hylidae family (H. cordobae and P. minuta) as reversible inhibitors of acetylcholinesterase and butyrylcholinesterase enzymes. Furthermore, the extracts inhibit MAO-B enzyme and showed antioxidant activities, acting on four important pathways of AD.
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Doença de Alzheimer/metabolismo , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Inibidores da Colinesterase/isolamento & purificação , Inibidores da Colinesterase/farmacologia , Inibidores da Monoaminoxidase/isolamento & purificação , Inibidores da Monoaminoxidase/farmacologia , Pele/química , Acetilcolinesterase/efeitos dos fármacos , Acetilcolinesterase/metabolismo , Doença de Alzheimer/enzimologia , Animais , Antioxidantes/administração & dosagem , Anuros/classificação , Butirilcolinesterase/efeitos dos fármacos , Butirilcolinesterase/metabolismo , Células CHO , Inibidores da Colinesterase/administração & dosagem , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Cromatografia em Camada Fina , Cricetulus , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Eritrócitos/efeitos dos fármacos , Eritrócitos/enzimologia , Humanos , Monoaminoxidase/efeitos dos fármacos , Monoaminoxidase/metabolismo , Inibidores da Monoaminoxidase/administração & dosagem , Especificidade da Espécie , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Espectrofotometria UltravioletaRESUMO
Chlorpyrifos (CPF) is a broad spectrum pesticide commonly used for insect control, has great affinity for lipids and is thus a potential for bioaccumulation in aquatic organisms. The aim of this study was to evaluate the toxicity of CPF using the common toad Rhinella arenarum via dermal uptake in plastic bucket to simulate their natural exposition in ponds. R. arenarum toads were exposed individually to solutions containing a nominal concentration of a commercial formulation of CPF insecticide (5 and 10 mg/L). Different enzyme biomarkers (BChE: butyrylcholinesterase, CbE: carboxylesterase, and CAT: catalase) were measured in blood tissue after exposition. The capacity of pyridine-2-aldoxime methochloride (2-PAM) to reverse OP-inhibited plasma BChE and the ratio of heterophils and lymphocytes (H/L) as hematological indicators of stress were also determined. The normal values of plasma B-sterases (BChE and CbE) were highly inhibited (until ≈ 70%) in toads 48 h after exposure to CPF. The results indicate that 2-PAM produced BChE reactivation as well. The activity of CAT was also inducted for dermal exposure at more than double of that in the control toads (CPF; 5 mg/L). H/L ratios did not reveal a significantly increased stress. The study suggests that CPF via dermal uptake induced neurotoxicity and oxidative stress in the common toad R. areanum. Thus, some blood biomarkers employed in our study (i.e. BChE, CbE, 2-PAM, and CAT) might be used as predictors in health and ecological risk assessment of amphibian populations exposed to CPF.
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The ecological risks posed by two ß-diketone antibiotics (DKAs, enrofloxacin, ENR and ciprofloxacin, CPX), characterized by their long persistence in aqueous environments and known deleterious effect on model organisms such as zebrafish were analysed using Rhinella arenarum larvae. Sublethal tests were conducted using environmentally relevant concentrations of both ENR and CPX (1-1000µgL-1) under standard laboratory conditions for 96h. Biological endpoints and biomarkers evaluated were body size, shape, development and growth rates, and antioxidant enzymes (glutathione-S-transferase, GST; Catalase, CAT). Risk assessment was analysed based on ration quotients (RQ). The size and shape measurements of the larvae exposed to concentrations greater than 10µgL-1 of CPX were lower compared to controls (Dunnett post hoc p<0.05) and presented signs of emaciation. Concentrations of 1000µgL-1of CPX induced GST activity, in contrast with inhibited GST and CAT of larvae exposed to ENR. Risk assessments indicated that concentrations greater than or equal to10µgL-1 of CPX and ENR are ecotoxic for development, growth, detoxifying, and oxidative stress enzymes. It is suggested that additional risk assessments may provide evidence of bioaccumulation of CPX and ENR in tissues or organs of amphibian larvae by mesocosm sediment test conditions. Finally, intestinal microbiome studies should be considered to establish the mechanisms of action of both antibiotics.
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Antibacterianos/toxicidade , Ciprofloxacina/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Fluoroquinolonas/toxicidade , Drogas Veterinárias/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Argentina , Bufonidae , Ecotoxicologia , Embrião não Mamífero/metabolismo , Enrofloxacina , Monitoramento Ambiental , Larva , Estresse Oxidativo/efeitos dos fármacos , Testes de Toxicidade AgudaRESUMO
Retinoids are known to regulate important processes such as differentiation, development, and embryogenesis of vertebrates: Alteration in endogenous retinoids concentration is linked with teratogenic effects. Retinol (ROH), retinoid acid (RA), and isoform 13-Cis-retinoic acid (13-Cis-RA), in plasma of a native adults frog, Leptodactylus chaquensis from a rice field (RF) and a forest (reference site; RS) were measured. ROH did not vary between treatment sites. RA and 13-Cis-RA activities were higher (93.7±8.6 µg mL(-1) and 131.7±11.4 µg mL(-1), respectively) in individuals collected from RF than in those from RS (65.5±8.6 µg mL(-1) and 92.2±10.2 µg mL(-1), respectively). The ratios retinoic acid-retinol (RA/ROH) and 13-Cis-RA/ROH revealed significantly higher values in RF than in RS. RA and 13-Cis-RA concentrations in plasma on wild amphibian's species such as L. chaquensis would be suitable biomarkers of pesticide exposure in field monitoring. Finally, the mechanism of alteration in retinoid metabolites alteration should be further explored both in larvae and adult, considering that the potential exposition and uptake contaminants vary between the double lives of these vertebrates.
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Anuros/sangue , Monitoramento Ambiental , Oryza , Ranidae/sangue , Retinoides/sangue , Adulto , Agricultura , Animais , Argentina , Ecossistema , Humanos , Larva , TretinoínaRESUMO
We examined the diet of the Rosy-billed Pochard, Netta peposaca (Vieillot, 1816), (n = 59) during the autumn of 2010 in Santa Fe province, Argentina. Were analyzed a total of 59 ducks (n = 37 females and n = 22 males) to assess their gastrointestinal contents. The trophic spectrum was composed of 16 taxa (plant fraction: animal fraction 9 and 7). The contribution of each food category estimated using the IRI was: Echynochloa sp. (Poaceae) = 4301, Polygonum sp. (Polygonaceae) = 956, and unidentified graminoid species = 53 (females: Echynochloa sp. = 4313, Polygonum sp. = 1095 and males: Echynochloa sp. = 5522, Polygonum sp. = 814). No significant differences were found between females and males in diet composition (Fisher's test, p < 0.05). Moreover, the diversity index (H') was significantly (Mann-Whitney, p < 0.05) different between sexes. The Rosy-billed Pochard showed a predominantly phytophagous feeding habit in autumn. Likewise, this is the first contribution on the sexual differences in the feeding biology of the Rosy-billed Pochard.(AU)
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Animais , Anseriformes/fisiologia , Dieta/veterinária , Comportamento Alimentar , ArgentinaRESUMO
We examined the diet of the Rosy-billed Pochard, Netta peposaca (Vieillot, 1816), (n = 59) during the autumn of 2010 in Santa Fe province, Argentina. Were analyzed a total of 59 ducks (n = 37 females and n = 22 males) to assess their gastrointestinal contents. The trophic spectrum was composed of 16 taxa (plant fraction: animal fraction 9 and 7). The contribution of each food category estimated using the IRI was: Echynochloa sp. (Poaceae) = 4301, Polygonum sp. (Polygonaceae) = 956, and unidentified graminoid species = 53 (females: Echynochloa sp. = 4313, Polygonum sp. = 1095 and males: Echynochloa sp. = 5522, Polygonum sp. = 814). No significant differences were found between females and males in diet composition (Fisher's test, p < 0.05). Moreover, the diversity index (H') was significantly (Mann-Whitney, p < 0.05) different between sexes. The Rosy-billed Pochard showed a predominantly phytophagous feeding habit in autumn. Likewise, this is the first contribution on the sexual differences in the feeding biology of the Rosy-billed Pochard.
Assuntos
Animais , Anseriformes/fisiologia , Comportamento Alimentar , Dieta/veterinária , ArgentinaRESUMO
Sediments are important elements of aquatic ecosystems and in general sediments accumulate diverse toxic substances. Amphibians potentially have a greater risk of exposure to contaminants in sediments, and the test of sediments provides first lines of evidences. Sediment outdoor microcosm experiments were conducted to analyze biological endpoints (survival, development, growth, and morphological and organ malformation), enzyme activity (butyrylcholinesterase, BChE; glutathione-S-transferase, GST; and catalase, CAT) and blood biomarkers in veined treefrog Trachycephalus typhonius tadpoles, a widespread neotropical species. Hatching (stage 23) of T. thyphonius was exposed until they reached metamorphosis (stage 46). Sediment tests were performed and four different treatments were used: three ponds (LTPA, ISP, and SSP) influenced by industrial and agricultural activities and a reference treatment from a forest (RFS). Physical and chemical variables and concentration of nutrients, pesticide residues, and metals were determined. One treatment was metal-rich (LPTA) and two were nutrient-rich (ISP and SSP). Sediment treatments had no significant effect on survival; in contrast they had significant sublethal effects on T. typhonius larval development and growth rates, and affected overall size and shape at stage 38. Principally, in LPTA animals were significantly larger than in RFS, exhibiting swollen bodies, tail muscles and tail fin. In addition, metamorphs from LPTA, ISP, and SSP were smaller and showed signs of emaciation by the end of the experiment. Statistical comparisons showed that the proportions of each type of morphological abnormalities (swollen bodies and diamond shape, gut uncoiling, diverted gut, stiff tails, polydactyly, and visceral and hindlimb hemorrhaging) were significantly greater in metal- and nutrient-rich sediment treatments. Moreover, activities of BChE, GST and CAT, as well as and presence of micronuclei, immature, mitotic, anucleated erythrocytes varied significantly among treatments. Our biological effects-based sediment study highlights the use of different biological endpoints and biomarkers on anuran larvae at sites where pond sediment is risky and sediment management should be considered. Finally, the information of those biological endpoints and biomarkers would be useful as a management tool to decide if there are sufficient exposures of tadpoles to suspected pollutants on sediment.
Assuntos
Anuros/crescimento & desenvolvimento , Anuros/metabolismo , Sedimentos Geológicos/química , Poluentes da Água/efeitos adversos , Animais , Anuros/anormalidades , Argentina , Biomarcadores/análise , Butirilcolinesterase/análise , Catalase/análise , Glutationa Transferase/análise , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Metamorfose Biológica/efeitos dos fármacos , LagoasRESUMO
In this study, amphibian tadpoles of Hypsiboas pulchellus were exposed to herbicide Liberty®, which contains glufosinate ammonium (GLA), for 48 h to the following concentrations: 0 (control), 3.55, 4.74, 6.32, 8.43, 11.25, 15, 20, 26.6, and 35.5 mg GLA L(-1). Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities, as well as swimming capabilities (swimming speed and mean distance) were measured in tadpoles whose concentrations displayed survival rates > 85 %. Our results reveal that sublethal concentrations of GLA significantly inhibited both AChE and BChE activities in tadpoles with respect to the control, showing a concentration-dependent inhibitory effect. The highest inhibition percentages of AChE (50.86%) and BChE (53.02%) were registered in tadpoles exposed to 15 mg GLA L(-1). At this concentration, a significant increase of the swimming speed and mean distance were found in exposed tadpoles with respect to the control, as well as a negative and significant correlation between swimming speed and BChE activity, thus suggesting that this enzyme inhibition is related to an increase in swimming speed. Therefore, exposure of tadpoles to GLA in the wild at concentrations similar to those tested here may have adverse consequences at population level because neurotransmission and swimming performance are essential for tadpole performance and survival.
Assuntos
Acetilcolinesterase/metabolismo , Aminobutiratos/toxicidade , Anuros/metabolismo , Herbicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/toxicidade , Relação Dose-Resposta a Droga , Monitoramento Ambiental , Larva/efeitos dos fármacos , Natação/fisiologia , Transmissão Sináptica/efeitos dos fármacos , Testes de Toxicidade AgudaRESUMO
The H(2)O(2)/UVC process was applied to the photodegradation of a commercial formulation of glyphosate in water. Two organisms (Vibrio fischeri bacteria and Rhinella arenarum tadpoles) were used to investigate the toxicity of glyphosate in samples M(1,) M(2), and M(3) following different photodegradation reaction times (120, 240 and 360 min, respectively) that had differing amounts of residual H(2)O(2). Subsamples of M(1), M(2), and M(3) were then used to create samples M(1,E), M(2,E) and M(3,E) in which the H(2)O(2) had been removed. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were measured in tadpoles to determine possible sub-lethal effects. In V. fischeri, M(1,E), which was collected early in the photodegradation process, caused 52% inhibition, while M(3,E), which was collected at the end of the photodegradation process, caused only 17% inhibition. Survival of tadpoles was 100% in samples M(2), M(3), and in M(1,E), M(2,E) and M(3,E). The lowest percentages of enzymatic inhibition were observed in samples without removal of H(2)O(2): 13.96% (AChE) and 16% (BChE) for M(2), and 24.12% (AChE) and 13.83% (BChE) for M(3). These results show the efficiency of the H(2)O(2)/UVC process in reducing the toxicity of water or wastewater polluted by commercial formulations of glyphosate. According to the ecotoxicity assays, the conditions corresponding to M(2) (11 ± 1 mg a.e. L(-1) glyphosate and 11 ± 1 mg L(-1) H(2)O(2)) could be used as a final point for glyphosate treatment with the H(2)O(2)/UV process.