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1.
Ecotoxicol Environ Saf ; 213: 112061, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33636466

RESUMO

Maize seed treatment with chemicals to control underground pests is a common agricultural practice, but inappropriate use of insecticides poses a considerable threat to plant development and soil nontarget organisms. In this study, the availability of tetraniliprole seed dressing to control the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae) in the maize seeding stage and its safety to earthworms (Eisenia fetida) were investigated. The selective toxicity (ST) of tetraniliprole between E. fetida and A. ipsilon was greater than 4000. No significant adverse effect of tetraniliprole seed treatment on the germination of maize seeds was observed at concentrations of 2.4-9.6 g a.i. /kg seed. Compared with the untreated control, seed treatment with tetraniliprole at 9.6 g a.i. /kg seed greatly reduced the percentage of damaged plants from 88.73% to 26.67%, and achieved the highest control effect of 69.91%. Tetraniliprole of 2.4 g a.i. /kg seed can effectively inhibit A. ipsilon until 14 days after seed germination, with the lowest mortality rate of 44.44%. During the entire exposure period, the maximum residual concentration of tetraniliprole detected in the soil (5.86 mg/kg) was considerably lower than the LC50 value of tetraniliprole to E. fetida (>4000 mg/kg). According to the low-tier risk assessment, the highest risk quotient (RQ) of tetraniliprole seed treatment to earthworms at test concentrations was 2.8 × 10-3, which was evaluated as acceptable. This study provided data support for tetraniliprole seed treatment to control underground pests in maize fields.


Assuntos
Inseticidas/toxicidade , Pirazóis/toxicidade , Piridinas/toxicidade , Poluentes do Solo/toxicidade , Tetrazóis/toxicidade , Animais , Inseticidas/análise , Mariposas , Oligoquetos , Pirazóis/análise , Piridinas/análise , Medição de Risco , Sementes/química , Solo/química , Poluentes do Solo/análise , Tetrazóis/análise , Zea mays
2.
Ecotoxicol Environ Saf ; 210: 111875, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33454577

RESUMO

Coccinella septempunctata (ladybird) is one of the foremost natural predators that feed on aphids. Thus, C. septempunctata serves as an effective biological control agent in integrated pest management (IPM) programs. To supplement the activity of biological control agents, IPM programs often incorporate chemical pesticides to bolster crop protection. To evaluate the effects of a potent insecticide, tolfenpyrad, on C. septempunctata, we tested the sublethal effects of tolfenpyrad on all developmental stages of the life cycle of C. septempunctata and its effects on the next generation. For sublethal testing of the parent generation, the LR50 of tolfenpyrad for C. septempunctata was determined to range from 1.04 to 8.43 g a.i. /hm2 within a set exposure period, while the hazard quotient (HQ) values were above our threshold value of 2 during the entire observation period. These data indicated a potential toxicity risk from tolfenpyrad exposure. The no observed effect application rates (NOERs) of tolfenpyrad on parents (F0) were determined for survival (0.485 g a.i. /hm2), developmental time of pupation (0.242 g a.i. /hm2), and fecundity (0.485 g a.i. /hm2). Application of sublethal doses to unexposed progeny (F1) of exposed parents, prolonged the L1 (1st instar of larvae) and L2 (2nd instar of larvae) stage, while the total longevity, intrinsic rate of increase (r), finite rate of increase (γ), net reproductive rate (R0), and mean generation time (T) were significantly reduced. These results demonstrated the negative influence of sublethal concentrations of tolfenpyrad on C. septempunctata and its persistent effects on subsequent generations.


Assuntos
Besouros/efeitos dos fármacos , Inseticidas/toxicidade , Pirazóis/toxicidade , Animais , Besouros/fisiologia , Feminino , Fertilidade/efeitos dos fármacos , Larva/efeitos dos fármacos , Larva/fisiologia , Estágios do Ciclo de Vida/efeitos dos fármacos , Masculino , Controle de Pragas , Reprodução/efeitos dos fármacos
3.
Ecotoxicol Environ Saf ; 208: 111622, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396142

RESUMO

The continuous growth in global population since the beginning of the 20th century result in the necessity of food and energy provision favoring the intensive use of agricultural products such as pesticides. Although pesticides are important to prevent losses in the conventional chemically based agriculture, they frequently present side effects, which goes against agricultural production. The use of pesticides cause direct and indirect effects to soil organisms unbalancing essential soil processes (e.g. primary production, organic matter decomposition, nutrient cycling). Under tropical conditions, very little is known regarding the effects of pesticides to terrestrial organisms. Hence, the aim of the present study was to assess the ecotoxicological effects of the herbicide DMA® 806 BR (active ingredient: 2,4-D) and the insecticide Regent® 800 WG (active ingredient: fipronil), on terrestrial plant species (the dicot Raphanus sativus var. acanthioformis and the monocot Allium cepa), and soil invertebrates (the collembolan Folsomia candida and the enchytraeid Enchytraeus crypticus), using natural (NS) and artificial soils (TAS). For both pesticides, negative effects on non-target species were observed at concentrations lower than the doses recommended to prevent pests in sugarcane fields. For both soils, the dicot species was the most affected by the herbicide (R. sativus > A. cepa > F. candida > E. crypticus) and the collembolan species was the most affected by the insecticide (F. candida > E. crypticus = R. sativus = A. cepa). Although the order of the organisms' sensitivity for both pesticides was the same in both soils, results showed that the extent of the effects was soil dependent. Considering the ecologically relevant concentrations tested, and their severe effects to non-target organisms, it may be concluded that the use of fipronil and 2,4-D under recommended conditions may pose a risk to the terrestrial environment.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Praguicidas/toxicidade , Pirazóis/toxicidade , Saccharum/fisiologia , Poluentes do Solo/análise , Agricultura , Animais , Artrópodes/efeitos dos fármacos , Artrópodes/fisiologia , Ecotoxicologia , Inseticidas/toxicidade , Oligoquetos/efeitos dos fármacos , Oligoquetos/fisiologia , Solo/química
4.
Ecotoxicol Environ Saf ; 209: 111778, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33338803

RESUMO

Increased use of pesticides in conventional agriculture implies potential risks to the environment. In aquatic ecosystems, benthic organisms may be exposed to pesticides via contaminated water and sediment, leading to several potential cascading effects on the food web. The aim of this study was to assess the functional implications of environmental realistic concentrations of the herbicide 2,4-D and the insecticide fipronil (alone and in combination) to the native tropical chironomid Chironomus sancticaroli. These two pesticides are widely applied to different crops and have frequently been detected (together) in surface water bodies in Brazil and elsewhere. Commercial products containing fipronil (Regent® 800WG) and 2,4-D (DMA® 806BR) were evaluated in 8-day toxicity tests for their effects on larval survival, growth (body length and biomass), head capsule width, development, and mentum deformities. Fipronil decreased the larval survival at the highest test concentration and the effective concentrations (EC) after eight days of exposure were: EC10 = 0.48 µg L-1 (0.395-0.565), EC20 = 1.06 µg L-1 (0.607-1.513), and EC50 = 3.70 µg L-1 (1.664-5.736). All sublethal test concentrations of fipronil decreased the larval growth, causing reductions in biomass up to 72%. The two highest test concentrations of fipronil decreased the head capsule width and after exposure to 3.7 µg fipronil L-1, only half of the larvae reached the fourth instar. The incidence of deformities was increased by fipronil in a concentration dependent manner with an increase ranging from 23% to 75%. The highest test concentration of 2.4-D (426 µg L-1) decreased the head capsule width, but larval development was unaffected at all concentrations evaluated. In the mixture tests, antagonism was observed at lower fipronil concentrations and synergism at higher fipronil concentrations for growth. The incidence of deformities rose with increasing fipronil concentrations. The results showed that environmental realistic concentrations of fipronil may have serious ecological implications for C. sancticaroli populations and that a mixture with the herbicide 2,4-D can have synergistic effects, potentiating the risks to the aquatic ecosystem.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Chironomidae/efeitos dos fármacos , Praguicidas/toxicidade , Pirazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Brasil , Chironomidae/crescimento & desenvolvimento , Ecossistema , Inseticidas , Larva , Testes de Toxicidade , Poluição da Água
5.
Ecotoxicol Environ Saf ; 209: 111824, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360783

RESUMO

Cyantraniliprole is a novel diamide insecticide that acts upon the ryanodine receptor (RyR) and has broad application prospects. Accordingly, it is very important to evaluate the toxicity of cyantraniliprole to earthworms (Eisenia fetida) because of their vital role in maintaining a healthy soil ecosystem. In this study, an experiment was set up, using four concentrations (0.1, 1, 5, and 10 mg/kg) and solvent control group (0 mg/kg), to investigate the ecotoxicity of cyantraniliprole to earthworms. Our results showed that, after 28 days of exposure to cyantraniliprole, both cocoon production and the number of juvenile earthworms had decreased significantly at concentrations of either 5 or 10 mg/kg. On day 14, we measured the activities of digestive enzymes and ion pumps in the intestinal tissues of earthworms. These results revealed that cyantraniliprole exposure caused intestinal damage in earthworm, specifically changes to its intestinal enzyme activity and calcium ion content. Cyantraniliprole could lead to proteins' carbonylation under the high-dose treatments (i.e., 5 mg/kg, 10 mg/kg). At the same time, we also found that cyantraniliprole can cause the abnormal expression of key functional genes (including HSP70, CAT, RYR, ANN, and CAM genes). Moreover, the transcriptomics data showed that exposure to cyantraniliprole would affect the synthesis of carbohydrates, proteins and lipids, as well as their absorption and transformation, while cyantraniliprole would also affect signal transduction. In general, high-dose exposure to cyantraniliprole causes reproductive toxicity, genotoxicity, and intestinal damage to earthworms.


Assuntos
Inseticidas/toxicidade , Oligoquetos/fisiologia , Pirazóis/toxicidade , Poluentes do Solo/toxicidade , ortoaminobenzoatos/toxicidade , Animais , Dano ao DNA , Ecossistema , Solo , Poluentes do Solo/análise , Transcriptoma
6.
Toxicol Appl Pharmacol ; 411: 115367, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33340518

RESUMO

Pexacerfont is a corticotrophin-releasing factor subtype 1 receptor (CRF-1) antagonist developed for potential treatment of anxiety and stress-related disorders. In male rats, pexacerfont caused hepatic enzyme induction leading to increased thyroxine (T4) clearance. When administered to pregnant rats on gestation day 6 to 15, pexacerfont at 300 mg/kg/day (30× mean AUC in humans at 100 mg/day) produced similar effects on thyroid homeostasis with serum T4 and thyroid-stimulating hormone levels that were 0.3-0.5× and 3.3-3.7× of controls, respectively. At this dose, fetuses of pexacerfont-treated dams presented findings associated with maternal hypothyroidism including growth retardation and increased skeletal alterations. Additionally, there were unexpected great vessel malformations that were mostly derived from the 4th pharyngeal arch artery in 5 (4.3%) fetuses from 3 (15.8%) litters. The etiology was unclear whether the vascular malformations were related to insufficient thyroid hormones or another mechanism. To better understand this relationship, pregnant rats were implanted with a subcutaneous L-thyroxine pellet designed to provide a sustained release of T4 throughout organogenesis in rat embryos (GD 6 to 15; the dosing period of pexacerfont). T4 supplementation produced a near euthyroid state in pexacerfont-treated dams and completely prevented the fetal vascular malformations. These results suggest maternal T4 levels during organogenesis may have a role in great vessel morphogenesis associated with patterning and/or regression of pharyngeal arch arteries. Although previous clinical reports have speculated a potential relationship between thyroid hormone homeostasis and early cardiovascular development, this is the first report to experimentally demonstrate this relationship in great vessel morphogenesis.


Assuntos
Aorta/efeitos dos fármacos , Antagonistas de Hormônios/toxicidade , Pirazóis/toxicidade , Tiroxina/farmacologia , Triazinas/toxicidade , Malformações Vasculares/prevenção & controle , Animais , Aorta/anormalidades , Implantes de Medicamento , Feminino , Idade Gestacional , Hipotireoidismo/sangue , Hipotireoidismo/induzido quimicamente , Hipotireoidismo/prevenção & controle , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino , Exposição Materna , Morfogênese , Organogênese , Gravidez , Complicações na Gravidez/sangue , Complicações na Gravidez/induzido quimicamente , Complicações na Gravidez/prevenção & controle , Ratos , Tireotropina/sangue , Tiroxina/administração & dosagem , Tiroxina/sangue , Toxicocinética , Malformações Vasculares/sangue , Malformações Vasculares/induzido quimicamente
7.
Toxicol Mech Methods ; 31(1): 73-80, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33050807

RESUMO

In this study, changes in the blood tissue of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) caused by Fipronil (FP) insecticide were investigated using different biomarkers (Hematology parameters, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), malondialdehyde (MDA), paraoxonase (PON), arylesterase (ARE), myeleperoxidase (MPO), micronucleus (MN), 8-hydroxy-2-deoxyguanosine (8-OHdG)) level and caspase-3 activity. Statistically significant alterations in hematology parameters occurred with FP effect. In blood tissue, dose-dependent inhibition was determined in SOD-CAT-GPX-PON and ARE enzyme activities, but MDA and MPO were induced statistically significant. The results of MN assay were compared with the control group and it was obtained that genotoxicity of different dose groups was similar. The level of 8-OHdG and the activity and caspase-3 examined in blood tissue was increased depending on the dose. It was determined with different biomarkers that this insecticide caused physiological stress changes in the tissues examined.


Assuntos
Apoptose/efeitos dos fármacos , Dano ao DNA , Inseticidas/toxicidade , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Oncorhynchus mykiss , Estresse Oxidativo/efeitos dos fármacos , Pirazóis/toxicidade , Poluentes Químicos da Água/toxicidade , 8-Hidroxi-2'-Desoxiguanosina/sangue , Animais , Biomarcadores/sangue , Caspase 3/sangue , Relação Dose-Resposta a Droga , Proteínas de Peixes/sangue , Oncorhynchus mykiss/sangue , Oncorhynchus mykiss/genética , Oncorhynchus mykiss/metabolismo
8.
Aquat Toxicol ; 231: 105712, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33340833

RESUMO

Sugarcane crops management in Brazil includes the use of pesticides, as well as alternative organic fertilizers such as vinasse obtained from waste of the ethanol industry. In order to assess the effects of the environmental contamination generated by such sugarcane practices, this study was aimed to investigate the effects of the pesticides 2,4-Dichlorophenoxyacetic acid (2,4-D) and fipronil, as well as vinasse, on the survival, behavior, and reproduction of the native epibenthic macroinvertebrate Hyalella meinerti through in situ and laboratory experiments. In situ assays were conducted in mesocosms with six treatments, i.e. untreated control, 2,4-D, fipronil, and vinasse, the mixture of the two pesticides, and both pesticides mixed with vinasse. Survival, swimming behavior, and reproduction were evaluated over time post contamination, from 0-96 h (T1) and 7-14 days (T2) through in situ experiments and 30-44 days (T3) and 75-89 days (T4) post contamination by laboratory bioassays with mesocosm water. In the T1 period, survival of H. meinerti was registered only in controls and mesocosms treated with 2,4-D. In the T2 period, treatments containing fipronil and vinasse (isolated or in both mixture treatments) still caused 100 % of mortality. Survival was recorded only in 2,4-D and control treatments, whereas reproduction only occurred in the control. In the T3 period, no survival occurred to fipronil and both mixture treatments. Vinasse and 2,4-D decreased total reproduction in comparison to control. In the T4 period, amphipods survival was detected when exposed to fipronil and its mixture with 2,4-D. However, these same treatments decreased the amplexus rates and total reproduction, with synergism denoted for the pesticide mixture. The swimming activity of males, females, and couples was decreased in surviving organisms exposed to 2,4-D, fipronil, vinasse, and the mixture of pesticides along all experimental periods. Our study showed that the application of fipronil, 2,4-D, and vinasse isolated or mixed at realistic concentrations of actual sugarcane management practices may negatively impact functional responses of indigenous amphipods in natural aquatic systems.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Anfípodes/fisiologia , Exposição Ambiental , Pirazóis/toxicidade , Resíduos , Anfípodes/efeitos dos fármacos , Animais , Comportamento Animal/efeitos dos fármacos , Brasil , Feminino , Masculino , Praguicidas/análise , Reprodução/efeitos dos fármacos , Análise de Sobrevida , Natação , Poluentes Químicos da Água/toxicidade , Qualidade da Água
9.
Aquat Toxicol ; 228: 105617, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32942115

RESUMO

In fish, the study of cholinesterases (ChEs) and carboxylesterases (CEs), apart from their involvement in neural activity and xenobiotic metabolism, respectively, requires to be further explored. The European sea bass (Dicentrarchus labrax) was the fish model used to characterise B-esterases in several matrices and organs, as well as to assess the impacts of the insecticide fipronil at two temperatures: the natural temperature at the time of sampling (13 °C) and at 16 °C (based on climate change-related predictions for the Mediterranean region). Fipronil exerts harmful effects in non-target species; however, some countries are reluctant to implement regulations without additional evidence on their toxicity. A comprehensive study was performed in fish pre-acclimated to the two targeted temperatures for 15 days. B-esterases were evaluated in multiple samples after 7 and 14 day exposures to fipronil in feed (dose of 10 mg/kg) and after a 7-day depurative period. Based on hydrolysis rates, results showed that CEs were measurable in all matrices while ChEs were more abundant in muscle and, particularly, acetylcholinesterase (AChE) in the brain. A + 3 °C increase in temperature had little influence on B-esterase activity; however, fipronil caused a significant increase in brain AChE (1.5-fold) and CE (3-fold) activities. Other matrices and organs also experienced alterations in their B-esterase activities that could compromise their physiological functions.


Assuntos
Aclimatação/efeitos dos fármacos , Bass/metabolismo , Carboxilesterase/metabolismo , Inseticidas/toxicidade , Pirazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Animais , Bass/fisiologia , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Temperatura
10.
Arch Environ Contam Toxicol ; 79(3): 298-309, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32860087

RESUMO

Aquatic environments are constantly exposed to a cocktail of contaminants mainly due to human activities. As polluted ecosystems may simultaneously present other multiple natural stressors, the objective of the present study was to evaluate joint effect of stressors (natural and anthropogenic) on life history traits of the Neotropical cladoceran, Ceriodaphnia silvestrii. For this purpose, the effects of water conditioned with predator kairomones (fish) and environmental concentrations (sublethal) of two pesticides widely used in sugarcane monoculture in Brazil, the insecticide Regent® 800 WG (active ingredient-a.i. fipronil) and the herbicide DMA® 806 BR (a.i. 2,4-D) were evaluated using chronic toxicity testing, isolated and in mixture, for this cladoceran species. The environmental risks of pesticides for tropical freshwater biota were also estimated from the risk quotient MEC/PNEC. Among the characteristics of the life history of C. silvestrii evaluated after 8 days of exposure, compared with the mean value of control, the age of primiparous females was not affected by any evaluated treatment. However, species average survival decreased in the treatment of kairomones mixed with fipronil (FK) and in the treatment with a mixture of fipronil, 2,4-D, and kairomones (MFKD). The body length of maternal females was shorter than in the control after exposure in treatments with only kairomones (K) and FK. Fecundity of this cladoceran was reduced when exposed to FK and MFKD treatments, and the intrinsic rate of population increase significantly decreased for organisms exposed to treatment with fipronil (F) and to mixtures of fipronil and 2,4-D (MFD), MFDK, and FK. The results indicated that the combination of anthropogenic and natural stressors causes changes in C. silvestrii life history traits, which can contribute to the decline in populations, and our preliminary risk assessment results are a matter of concern regarding biota conservation.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Cladóceros/efeitos dos fármacos , Traços de História de Vida , Feromônios/toxicidade , Pirazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Brasil , Ecossistema , Feminino , Fertilidade/efeitos dos fármacos , Peixes/metabolismo , Água Doce/química , Testes de Toxicidade Crônica
11.
Ecotoxicology ; 29(9): 1462-1475, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32860623

RESUMO

Brazil is the largest producer of sugarcane and the world's top pesticide market. Therefore, environmental consequences are of concern. The aim of the present study was to evaluate the acute and chronic toxicity of pesticide formulations largely used in sugarcane crops: the herbicide DMA® 806 BR (a.i. 2,4-D) and the insecticide Regent® 800 WG (a.i. fipronil), isolated and in mixture, to the Neotropical cladoceran Ceriodaphnia silvestrii. Toxicity tests with the individual formulated products indicated 48h-EC50 values of 169 ± 18 mg a.i./L for 2,4-D and 3.9 ± 0.50 µg a.i./L for fipronil. In the chronic tests, the 8d-EC50 values for reproduction were 55 mg a.i./L (NOEC/LOEC: 50/60 mg a.i./L) and 1.6 µg a.i./L (NOEC/LOEC: 0.40/0.80 µg a.i./L) for 2,4-D and fipronil, respectively. A significant decrease in reproduction of C. silvestrii in all concentrations tested of fipronil, except at the lowest, was observed. Regarding 2,4-D, the organisms had total inhibition of reproduction in the two highest concentrations. Probably your energy reallocation was focused (trade-off) only on its survival. The acute pesticide mixture toxicity (immobility) revealed a dose level dependent deviation with antagonism at low and synergism at high concentrations. For chronic mixture (reproduction) toxicity, antagonism occurred as a result of the interaction of the pesticides. Based on our results and concentrations measured in Brazilian water bodies, fipronil represents ecological risks for causing direct toxic effects on C. silvestrii. These results are worrisome given that agricultural production is likely to increase in the coming years.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Cladóceros/fisiologia , Praguicidas/toxicidade , Pirazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Brasil , Ecossistema , Inseticidas , Reprodução , Testes de Toxicidade , Testes de Toxicidade Crônica
12.
Ecotoxicol Environ Saf ; 206: 111180, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32861006

RESUMO

The occurrence of pesticides and their mixtures in the environment can alter the ecological relationships between aquatic food chains. Since fipronil and 2,4-dichlorophenoxyacetic acid (2,4-D) are commonly found together in Brazilian water bodies, the present study aimed to investigate through an integrative approach the toxicity mechanisms of environmentally relevant concentrations of pesticides Regent® 800 WG (active ingredient - a.i. fipronil), DMA® 806 BR (a.i. 2,4-D) isolated and in mixtures on the green alga Raphidocelis subcapitata using multiple parameters: physiological (growth rate and chlorophyll a fluorescence), morphological (cell complexity and size), biochemical (composition of lipid classes) and related to the photosynthetic activity (variable fluorescence, the maximum quantum yield of the photosystem II - PSII - and the efficiency of the oxygen evolving complex - OEC - of PSII). The results indicated that fipronil significantly inhibited algal population growth, increased the chlorophyll a content (observed by fluorescence), cell size and lipid class content of triacylglycerol (TAG), free fatty acid (FFA) and acetone mobile polar lipid (AMPL) and, on the other hand, decreased variable fluorescence of algae. The tested concentrations of 2,4-D increased the chlorophyll a fluorescence, the cell size and the lipid classes TAG and FFA. The pesticide mixtures have had more effects on algae than isolated compounds, causing alterations in all parameters analyzed, including photosynthetic activity (maximum quantum yield and efficiency of the oxygen evolving complex of the PSII), in which no alterations were observed for the toxicity of the single pesticides. The results suggest that these analyses are important to evaluate pesticide toxicity mechanisms in ecological risk assessments of tropical regions. Thus, here we demonstrate the importance of using multiple parameters in ecotoxicological studies to obtain a better understanding of the toxicity of these compounds for phytoplankton.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Clorofíceas/fisiologia , Pirazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Brasil , Clorofila/metabolismo , Clorofila A , Ecotoxicologia , Herbicidas/análise , Praguicidas/toxicidade , Fotossíntese/efeitos dos fármacos , Complexo de Proteína do Fotossistema II , Fitoplâncton/metabolismo
13.
J Environ Sci Health B ; 55(8): 687-693, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32432968

RESUMO

The objective of this research was to investigate the potential damage caused by the residual concentrations of the insecticides Regent® WS 800 and Curbix® SC 200, containing fipronil and ethiprole, respectively as active ingredients, on the liver of Oreochromis niloticus. The analyses of HSP70 shock protein labelling and cell death process by TUNEL method were performed in order to measure the effects of the exposure of cell repair system of fish to both insecticides. Statistical analyses showed no significant molecular damage to the hepatic tissue of animals. Nevertheless, variations in HSP70 and DNA fragmentation levels, endpoint of cell repair system response and cellular death, respectively, were observed in several groups. These results indicate that the cell repair machinery was efficient when in contact with residual concentrations of insecticides. However, the DNA fragmentation detected by the TUNEL method suggests that even in face of the cytoprotective action of the HSP70 protein, there are damages that become irreparable. To finish, it is worth mentioning that given the results obtained from residual concentrations, use in the field should be with caution.


Assuntos
Ciclídeos/fisiologia , Proteínas de Choque Térmico HSP70/metabolismo , Inseticidas/toxicidade , Pirazóis/toxicidade , Animais , Morte Celular/efeitos dos fármacos , Biomarcadores Ambientais/efeitos dos fármacos , Proteínas de Peixes/metabolismo , Fígado/efeitos dos fármacos , Resíduos de Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade
14.
J Environ Sci Health B ; 55(5): 477-483, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32449480

RESUMO

Pyraoxystrobin is a novel strobilurin fungicide that is widely used on many crops. The high log Kow of pyraoxystrobin implies that it tends to accumulate in aquatic organisms. This study optimized the sorbents of QuEChERS (quick, easy, cheap, effective, rugged, and safe) using 13C-labelled pyraoxystrobin as the internal standard (IS). It has been established a QuEChERS-LC-MS/MS IS method to study the bioconcentration and elimination of pyraoxystrobin in zebrafish (Danio rerio). The results indicated that the method had satisfactory linearity between 0.234 and 15 µg L-1 (R2 = 0.9996). The limits of detection (LOD) and quantification (LOQ) for pyraoxystrobin were 0.01 and 0.03 µg L-1, respectively. The LOQs of the method for water and zebrafish were 0.05 µg L-1 and 0.01 mg/kg, respectively. The mean recovery of pyraoxystrobin in zebrafish and water at fortification levels of 0.01-0.3 mg kg-1 and 0.05-1.5 µg L-1 ranged from 98.31 to 105.61% and 101.87 to 108.48%, respectively, with a % RSD (relative standard deviation) of 0.94-3.57%. The bioconcentration has been evaluated. The bioconcentration factors for pyraoxystrobin in zebrafish were 1,792 and 3,505 after exposure to 0.5 µg L-1 for 168 h and 0.05 µg L-1 for 216 h, respectively. The half-life of pyraoxystrobin in zebrafish was 9.0-9.5 d.


Assuntos
Acrilatos/análise , Acrilatos/farmacocinética , Fracionamento Químico/métodos , Pirazóis/análise , Pirazóis/farmacocinética , Peixe-Zebra , Acrilatos/toxicidade , Animais , Bioacumulação , Cromatografia Líquida , Ecotoxicologia/métodos , Fungicidas Industriais/análise , Fungicidas Industriais/farmacocinética , Fungicidas Industriais/toxicidade , Meia-Vida , Limite de Detecção , Pirazóis/toxicidade , Sensibilidade e Especificidade , Espectrometria de Massas em Tandem/métodos , Testes de Toxicidade Aguda , Poluentes Químicos da Água/análise
15.
J Med Chem ; 63(9): 4957-4977, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32330040

RESUMO

In humans, bitter taste is mediated by 25 TAS2Rs. Many compounds, including certain active pharmaceutical ingredients, excipients, and nutraceuticals, impart their bitter taste (or in part) through TAS2R8 activation. However, effective TAS2R8 blockers that can either suppress or reduce the bitterness of these compounds have not been described. We are hereby reporting a series of novel 3-(pyrazol-4-yl) imidazolidine-2,4-diones as potent and selective TAS2R8 antagonists. In human sensory tests, S6821 and S7958, two of the most potent analogues from the series, demonstrated efficacy in blocking TAS2R8-mediated bitterness and were selected for development. Following data evaluation by expert panels of a number of national and multinational regulatory bodies, including the US, the EU, and Japan, S6821 and S7958 were approved as safe under conditions of intended use as bitter taste blockers.


Assuntos
Hidantoínas/farmacologia , Pirazóis/farmacologia , Receptores de Superfície Celular/antagonistas & inibidores , Receptores Acoplados a Proteínas-G/antagonistas & inibidores , Paladar/efeitos dos fármacos , Animais , Café/química , Descoberta de Drogas , Estabilidade de Medicamentos , Humanos , Hidantoínas/síntese química , Hidantoínas/toxicidade , Estrutura Molecular , Pirazóis/síntese química , Pirazóis/toxicidade , Ratos , Relação Estrutura-Atividade
16.
Chemosphere ; 252: 126572, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32224362

RESUMO

The phenylpyrazole chiral insecticides, including the widely used fipronil, ethiprole, and flufiprole, have generated a worldwide interest due to their environmental toxicity. However, up to now,only few studies focused on their their potential endocrine-disrupting effects (EDEs). In this study, we investigated the endocrine hormonal disorder caused by the fipronil, ethiprole, and flufiprole enantiomers in vitro and in silico approach. Results of the luciferase reporter assay indicated that the enantiomers of fipronil, ethiprole, or flufiprole have shown stereoselective endocrine-disrupting effects. S-(-)-ethiprole and S-(-)-flufiprole have anti-thyroidal disorder effects whereas R-(-)-fipronil, R-(+)-ethiprole, and R-(+)-flufiprole showed anti-estrogenic disorder effects. The results of the molecular dynamics simulations revealed that the happened EDEs could be partially attributed to the enantioselective specific receptor binding affinities. It also suggested that Vander Waals interactions plays an important role in the binding procedure. This study could provide helpful information for the explanation of enantioselectivity in the EDEs of chiral phenylpyrazole pesticides at the molecular level.


Assuntos
Disruptores Endócrinos/toxicidade , Inseticidas/toxicidade , Animais , Simulação por Computador , Disruptores Endócrinos/química , Inseticidas/química , Praguicidas/química , Pirazóis/toxicidade , Estereoisomerismo
17.
PLoS One ; 15(4): e0229151, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236101

RESUMO

The translocation of chemical insecticides in corn plants could enhance the control of Spodoptera frugiperda, based on their application form. Chlorantraniliprole and cyantraniliprole were applied via seed treatment and foliar spray in corn (VE and V3) to characterize the systemic action of both molecules in leaves that appeared after application. Bioassays with S. frugiperda and chemical quantification in LC-MS/MS confirmed the absorption and upward translocation of chlorantraniliprole and cyantraniliprole by xylem to new leaves. Both insecticides caused the mortality of larvae up to stage V6 (57.5±9.5% for chlorantraniliprole and 40±8.1% for cyantraniliprole), indicating the translocation of insecticides into leaves of corn plants when applied via seed treatment. However, the translocation of chlorantraniliprole and cyantraniliprole from sprayed leaves to new leaves was not observed, regardless of the stage of application plus the next first, second and third stages. An increased dosage of cyantraniliprole did not influence on its translocation in plant tissues, however, it influenced on the present amount of active ingredient. The application of chlorantraniliprole and cyantraniliprole in seed treatment is an important alternative for integrated pest management. The absorption and redistribution capacity of chlorantraniliprole and cyantraniliprole throughout the plant confer a prolonged residual action with satisfactory control of S. frugiperda.


Assuntos
Controle de Insetos/métodos , Inseticidas/toxicidade , Pirazóis/toxicidade , Spodoptera/efeitos dos fármacos , Zea mays , ortoaminobenzoatos/toxicidade , Animais , Larva/efeitos dos fármacos , Folhas de Planta , Sementes
18.
Chemosphere ; 249: 126479, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32208218

RESUMO

As part of a new generation of diamide insecticides, cyantraniliprole has broad application prospects. In the present study, a QuEChERS-UPLC-MS/MS method was established to determine the residues of cyantraniliprole and its main metabolite J9Z38 in soil and earthworms. Moreover, the accumulation and toxicity of cyantraniliprole and J9Z38 in earthworms were evaluated. The present results show that the detection method of cyantraniliprole and J9Z38 has high sensitivity and accuracy, which could be used for the accurate quantification of cyantraniliprole and J9Z38 residues in soil and earthworms. Additionally, cyantraniliprole degraded faster than its main metabolite J9Z38 in the artificial soil. Moreover, the bioenrichment efficiency of cyantraniliprole was higher than J9Z38. The toxicity test result showed that cyantraniliprole and J9Z38 could induce oxidative stress effect in earthworms from 5.0 mg/kg, finally resulting in cellular damage. Moreover, the oxidative damage degree induced by cyantraniliprole was higher than J9Z38. Combining the results of residue test and toxicity test, although cyantraniliprole degraded faster than its main metabolite J9Z38 in the artificial soil, its risk to earthworms was higher than J9Z38.


Assuntos
Inseticidas/toxicidade , Resíduos de Praguicidas/toxicidade , Pirazóis/toxicidade , ortoaminobenzoatos/toxicidade , Animais , Cromatografia Líquida , Diamida , Inseticidas/análise , Oligoquetos/efeitos dos fármacos , Resíduos de Praguicidas/análise , Pirazóis/análise , Solo/química , Poluentes do Solo/análise , Espectrometria de Massas em Tandem/métodos , Testes de Toxicidade , ortoaminobenzoatos/análise
19.
Artigo em Inglês | MEDLINE | ID: mdl-32121376

RESUMO

Fipronil is an insecticide widely used for veterinary and agricultural purposes. While its insecticidal properties mostly rely on its high affinity antagonistic activity on insect γ aminobutyric acid (GABA) receptors, fipronil and its main metabolite fipronil sulfone nevertheless display non-negligible affinity for mammalian GABAA receptor. As several environmental toxicants have been shown to raise the risk of developing various neurodegenerative disorders, the aim of this study was to evaluate whether long-term low dose administration of fipronil could lead to cognitive deficiencies. Our results indicate that long-term fipronil treatment leads to behavioral perturbations in mice, indicating an accumulative effect of sustained exposure to low dose of fipronil. Although no memory impairment was observed during the course of our study, we noticed a significant hyperlocomotion behavior after 43 weeks of weekly fipronil administration, which is consistent with its direct effect on the GABAergic system.


Assuntos
Hipercinese , Inseticidas , Pirazóis , Animais , Feminino , Hipercinese/induzido quimicamente , Inseticidas/toxicidade , Camundongos , Pirazóis/toxicidade , Receptores de GABA/efeitos dos fármacos , Ácido gama-Aminobutírico
20.
Proc Biol Sci ; 287(1922): 20192665, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32156210

RESUMO

In addition to controlling pest organisms, the systemic neurotoxic pesticide fipronil can also have adverse effects on beneficial insects and other non-target organisms. Here, we report on the sublethal effects of fipronil on the farmland butterfly Pieris brassicae. Caterpillars were reared on plants that had been grown from seeds coated with fipronil or on leaf discs topically treated with a range of fipronil dosages (1-32 µg kg-1 on dry mass basis). Females that had developed on fipronil plants laid ca half the number of eggs than females that had developed on control plants. In the bioassay with leaf discs, longevity and lifetime egg production declined with increasing fipronil dosage. Remarkably, exposure to fipronil during larval development primarily affected the adult stage. Chemical analyses of leaf tissues collected from seed-treated plants revealed concentrations of fipronil and its degradation products close to the analytical limit of detection (less than or equal to 1 µg kg-1). The effective dosage was fivefold higher in the leaf-disc than in the whole-plant experiment. In the whole plant, degradation of fipronil to products that are more toxic than fipronil may explain this discrepancy. Neurotoxicity of insecticides at the level of detection decreases the probability of pinpointing insecticides as the causal agent of harmful effects on non-target organisms.


Assuntos
Borboletas/fisiologia , Inseticidas/toxicidade , Pirazóis/toxicidade , Animais , Reprodução/efeitos dos fármacos
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