RESUMO
The effect of the organophosphate fenitrothion (FS) on the non-target freshwater prawn Palaemonetes argentinus was studied. Initially, the 96-h lethal concentration (LC50) of FS was determined in adult prawns. Inhibition of cholinesterase (ChE) in the muscle and hemolymph was assessed. Then, in the hepatopancreas, the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) were analyzed. Lipid peroxidation (LPO) was also determined in the hepatopancreas. The 96-h LC50 value was 1.12 µg/L. Hemolymph ChE activity showed a significant decrease in exposed prawns to FS compared to the control group, while no significant differences in the muscle were observed between groups (p < 0.05). FS caused a significant increase in the activity of antioxidant enzymes SOD, CAT, and GST compared to the control group (p < 0.02). By contrast, LPO levels were not affected by the pesticide (p < 0.05). These results indicate that P. argentinus is very sensitive to organophosphorus which alter biochemical parameters that are related to antioxidant status. Thus, these parameters could be used as biomarkers for assessing water pollution.
Assuntos
Fenitrotion/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Catalase/metabolismo , Colinesterases/metabolismo , Monitoramento Ambiental , Água Doce , Glutationa Transferase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Palaemonidae/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Testes de Toxicidade AgudaRESUMO
Several agrochemicals like organophosphates are extensively used to control pests in agricultural practices but they also adversely affect non-target fauna. The effect of organophosphorous fenitrothion on the prawn Macrobrachium borellii was evaluated. The 96-h LC50 was determined. Activity of superoxide dismutase, catalase, glutathione-S-transferase and lipid oxidation levels, were evaluated in the hepatopancreas from adults exposed to sublethal fenitrothion concentrations for 1, 2, 4 and 7 days. In addition, superoxide dismutase mRNA expression, acetylcholinesterase inhibition and haemocyte DNA damage were determined. The 96-h LC50 was 4.24µg/l of fenitrothion. Prawn exposed to sublethal FS concentrations showed an increase of both catalase and superoxide dismutase activities, mainly after 2 and 4 days exposure and an increase of glutathione-S-transferase activity from day 2 to day 7 while lipid oxidation levels increased mainly on day 1. Superoxide dismutase transcripts were significantly higher in fenitrothion -treated prawns, indicating an induction mechanism. Hemolymph analysis showed that while acetylcholinesterase activity decreased after 2 days, haemocytes displayed most DNA damage after 7-day exposure to fenitrothion. These results indicate that prawn enzymes are highly sensitive to fenitrothion exposure, and these biological responses in M. borellii could be valuable biomarkers to monitor organophosphorous contamination in estuarine environments.
Assuntos
Fenitrotion/toxicidade , Palaemonidae/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , DNA/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Hemócitos/efeitos dos fármacos , Hepatopâncreas/efeitos dos fármacos , Hepatopâncreas/enzimologia , Dose Letal Mediana , Oxirredução , Palaemonidae/metabolismoRESUMO
OBJECTIVE: Fenitrothion residue is found primarily in soil, water and food products and can lead to a variety of toxic effects on the immune, hepatobiliary and hematological systems. However, the effects of fenitrothion on the male reproductive system remain unclear. This study aimed to evaluate the effects of fenitrothion on the sperm and testes of male Sprague-Dawley rats. METHODS: A 20 mg/kg dose of fenitrothion was administered orally by gavages for 28 consecutive days. Blood sample was obtained by cardiac puncture and dissection of the testes and cauda epididymis was performed to obtain sperm. The effects of fenitrothion on the body and organ weight, biochemical and oxidative stress, sperm characteristics, histology and ultrastructural changes in the testes were evaluated. RESULTS: Fenitrothion significantly decreased the body weight gain and weight of the epididymis compared with the control group. Fenitrothion also decreased plasma cholinesterase activity compared with the control group. Fenitrothion altered the sperm characteristics, such as sperm concentration, sperm viability and normal sperm morphology, compared with the control group. Oxidative stress markers, such as malondialdehyde, protein carbonyl, total glutathione and glutathione S-transferase, were significantly increased and superoxide dismutase activity was significantly decreased in the fenitrothion-treated group compared with the control group. The histopathological and ultrastructural examination of the testes of the fenitrothion-treated group revealed alterations corresponding with the biochemical changes compared with the control group. CONCLUSION: A 20 mg/kg dose of fenitrothion caused deleterious effects on the sperm and testes of Sprague-Dawley rats.
Assuntos
Fenitrotion/toxicidade , Inseticidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Animais , Masculino , Tamanho do Órgão/efeitos dos fármacos , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Espermatozoides/química , Testículo/química , Testículo/patologia , Fatores de TempoRESUMO
OBJECTIVE: Fenitrothion residue is found primarily in soil, water and food products and can lead to a variety of toxic effects on the immune, hepatobiliary and hematological systems. However, the effects of fenitrothion on the male reproductive system remain unclear. This study aimed to evaluate the effects of fenitrothion on the sperm and testes of male Sprague-Dawley rats. METHODS: A 20 mg/kg dose of fenitrothion was administered orally by gavages for 28 consecutive days. Blood sample was obtained by cardiac puncture and dissection of the testes and cauda epididymis was performed to obtain sperm. The effects of fenitrothion on the body and organ weight, biochemical and oxidative stress, sperm characteristics, histology and ultrastructural changes in the testes were evaluated. RESULTS: Fenitrothion significantly decreased the body weight gain and weight of the epididymis compared with the control group. Fenitrothion also decreased plasma cholinesterase activity compared with the control group. Fenitrothion altered the sperm characteristics, such as sperm concentration, sperm viability and normal sperm morphology, compared with the control group. Oxidative stress markers, such as malondialdehyde, protein carbonyl, total glutathione and glutathione S-transferase, were significantly increased and superoxide dismutase activity was significantly decreased in the fenitrothion-treated group compared with the control group. The histopathological and ultrastructural examination of the testes of the fenitrothion-treated group revealed alterations corresponding with the biochemical changes compared with the control group. CONCLUSION: A 20 mg/kg dose of fenitrothion caused deleterious effects on the sperm and testes of Sprague-Dawley rats.
Assuntos
Animais , Masculino , Ratos , Fenitrotion/toxicidade , Inseticidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Tamanho do Órgão/efeitos dos fármacos , Distribuição Aleatória , Ratos Sprague-Dawley , Espermatozoides/química , Fatores de Tempo , Testículo/química , Testículo/patologiaRESUMO
Environmental contaminants can disrupt interactions between aquatic species by altering community structure. We explored predator-prey interactions between marbled swamp juvenile eels (Synbranchus marmoratus; predator) and anuran tadpoles (Hypsiboas pulchellus; prey) in relation to two aspects: the importance of lateral line in the predator and whether the absence of light modifies predation rates; and the effect of a sub-lethal concentration of fenitrothion on both predator and prey. Eels were tested under two sensory conditions (lateral line intact and lateral line blocked by cobalt chloride) in dark conditions. Predation rates were evaluated using different treatments that combined predator and prey exposed or not to insecticide. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities were also measured in muscle samples of eels and tadpoles to explore whether fenitrothion affects predator and prey differentially. Marbled swamp eels were more efficient in feeding on tadpoles during the night than during the day, showing that lateral line makes an important contribution to prey detection and capture. Regarding pesticide effects, short-term (6 h) exposure to an ecologically relevant fenitrothion dose of 2.5 mg L(-1) altered the predator-prey relationship by changing prey behaviour, reducing prey detection and therefore increasing tadpole survival. At this concentration, the outcome of the predator-prey relationship appears biased in favor of the exposed tadpoles, which were released from predation risk, despite their altered behaviour and the higher inhibition percentages of tail BChE (70%) and AChE (51%) than in control individuals. Our study involving these model species and agrochemicals demonstrates that fenitrothion affected the outcome of a predator-prey relationship. Further studies are needed, in these species and other native amphibians, to investigate the nature of the mechanisms responsible for the adverse effects of pesticides on antipredator behaviour and predation efficiency.
Assuntos
Anuros/fisiologia , Inibidores da Colinesterase/toxicidade , Fenitrotion/toxicidade , Cadeia Alimentar , Sistema da Linha Lateral/efeitos dos fármacos , Smegmamorpha/fisiologia , Acetilcolinesterase/metabolismo , Animais , Butirilcolinesterase/metabolismo , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Larva/enzimologia , Mecanorreceptores/efeitos dos fármacos , Fotoperíodo , Comportamento Predatório/efeitos dos fármacos , Poluentes Químicos da Água/toxicidadeRESUMO
We determined the levels of brain acetylcholinesterase (AChE) and tail butyrylcholinesterase (BChE) activities in tadpoles of Odontophrynus americanus exposed to a commercial formulation of fenitrothion. The mean brain AChE activities in the controls tadpoles varied from 6.91 to 6.39 micromol min(-1) mg(-1) protein, whereas tail BChE activities ranged among 0.26 to 0.17 micromol min(-1) mg(-1) protein; the two sublethal concentrations of fenitrothion assayed produced AChE and BChE inhibition (p < 0.01). Brain AChE recovered a substantial level of activity with a maximum of 93.2%; after the transference of tadpoles to a free-pesticide solution, whereas tail BChE recovery showed a smaller increase (39%) in the activity at 168 hr after to transference to clear water. According with our results, we suggest that tadpole's tail BChE presents higher sensibility than brain AChE.
Assuntos
Acetilcolinesterase/metabolismo , Anuros/metabolismo , Butirilcolinesterase/metabolismo , Inibidores da Colinesterase/toxicidade , Fenitrotion/toxicidade , Inseticidas/toxicidade , Animais , Anuros/crescimento & desenvolvimento , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Larva/efeitos dos fármacos , Larva/enzimologia , Cauda/efeitos dos fármacos , Cauda/enzimologiaRESUMO
The effects of organophosphorus pesticides on higher functions of the central nervous system are not well understood yet. As a first approach, the acute and repeated effects of three organophosphorus pesticides on learning and memory capabilities of behaving adult rats were studied here. Prior to training, animals received acute or repeated (5-day, 15-day, and 30-day) doses of diazinon, malathion, or fenitrothion. Animals were trained with an operant conditioning test, using a fixed-interval (FI 2 min) paradigm. Fifteen days later, animals were tested for retention of the learned task. Specific modifications in some selected behavioral displays were also quantified across the training process. Although their motor behaviors were not affected, treated animals required longer times for the acquisition of the fixed-interval test than did controls. As opposed to controls, not all (45.8% for diazinon, 66.6% for malathion, and 62.5% for fenitrothion) treated animals reached criterion during the retention test. Specific behaviors, such as grooming, rearing, exploratory whisking, and freezing, were modified at different levels by some (or all) of the three organophosphorus pesticides. According to these results, the three organophosphorus pesticides used here affected the acquisition and, mainly, the retention of instrumental conditioning, using a fixed-interval paradigm. The presentation of some specific behavioral displays was also modified in treated animals.
Assuntos
Condicionamento Operante/efeitos dos fármacos , Inseticidas/toxicidade , Retenção Psicológica/efeitos dos fármacos , Análise de Variância , Animais , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Diazinon/toxicidade , Esquema de Medicação , Fenitrotion/toxicidade , Malation/toxicidade , Masculino , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Esterases from a fenitrothion-resistant strain (VOSF) of the saw-toothed grain beetle, Oryzaephilus surinamensis (L.), are presumed to play a role in conferring resistance to malathion, fenitrothion, and chlorpyrifos-methyl. Colorimetric assays showed a significant positive correlation between increased resistance to fenitrothion in strains of O. surinamensis examined and elevated esterase hydrolytic activity to substrates of p-nitrophenyl acetate, alpha-naphthyl acetate, and beta-naphthyl acetate. Esterase zymograms showed different banding patterns between VOSF and an insecticide-susceptible strain, VOS48. A major esterase in the VOSF strain, not detected in VOS48, was purified and characterized by chromatographic and electrophoretic techniques. On the basis of SDS-polyacrylamide gel eletrophoresis, the molecular mass of the purified esterase from VOSF was 130 kDa and consisted of two 65 kDa subunits. Additional properties of this enzyme are discussed.
Assuntos
Besouros/enzimologia , Esterases/isolamento & purificação , Fenitrotion/toxicidade , Inseticidas/toxicidade , Animais , Eletroforese em Gel de Poliacrilamida , Esterases/química , Esterases/metabolismo , Resistência a Inseticidas , Isoenzimas/química , Isoenzimas/isolamento & purificação , Cinética , Peso MolecularRESUMO
Estudou-se os efeitos tóxicos dos inseticidas esfenvalerato, fenitrotion, fenpropatrin e monocrotofos sobre as ninfas de E. kraemeri em cultura de feijoeiro. A pesquisa doi conduzida no município de Nepomuceno - MG, utilizando uma lavoura comerical de cultivar "Carioca". Os compostos foram diluídos em água nas doses recomendadas pelos fabricantes para o controle de pragas, sendo a aplicaçäo realizada através de um pulverizador costal, propiciando volume de aplicaçäo de 400 L/ha. Os resultados mostraram que todos os compostos controlaram a praga em questäo, porém o fenitrotion na dose de 750 g i.a./ha apresentou o maior nível médio de controle.
Assuntos
Animais , Pragas da Agricultura , Fabaceae , Hemípteros , Controle de Insetos , Inseticidas/toxicidade , Insetos/efeitos dos fármacos , Fenitrotion/toxicidade , Inseticidas/administração & dosagem , Monocrotofós/toxicidade , Ninfa/efeitos dos fármacosRESUMO
l-BSO injected at a sublethal dose in nymph V of Triatoma infestans produces a transient GSH depletion in the abdomen. A depletion of the total content of GSH was observed in nymph II fed with a sublethal concentration of l-BSO. Either ingestion or injection pretreatments of T. infestans nymph V with sublethal concentrations of l-BSO produced a slight synergism on the toxicity of fenitrothion. Feeding administration of a sublethal concentration of l-BSO to nymphs II of T. infestans resulted in a weak potentiation of the acute toxicity of DDT.