Influência da temperatura nas respostas aos biocidas diazinon e carbaril em Dilocarcinus pagei Stimpson, 1861
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Data
2016-03-01
Autores
Lima, Alexandre Vidotto Barboza [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
As mudanças climáticas globais têm recebido destaque na área da toxicologia aquática em função dos efeitos que as alterações na temperatura da água podem exercer nas respostas dos organismos aquáticos aos contaminantes ambientais. A temperatura corpórea dos organismos ectotérmicos, como os crustáceos, é totalmente dependente da temperatura do ambiente, de modo que aumentos na temperatura afetam diretamente o metabolismo desses animais, acelerando as reações bioquímicas e a absorção de muitos contaminantes aquáticos no organismo. Neste trabalho foi investigado a influência de três faixas de temperatura (18, 23 e 28 °C) na toxicidade dos biocidas diazinon (organofosforado) e carbaril (carbamato) nas brânquias e no hepatopâncreas de machos e fêmeas do caranguejo de água doce Dilocarcinus pagei, utilizando como parâmetros analíticos as enzimas antioxidantes glutationa S-tranferase (GST), glutationa peroxidase (GPx), glutationa redutase (GR), glicose 6-fosfato-desidrogenase (G6PDH), níveis de peroxidação lipídica por meio da formação do malondialdeído (MDA) e os efeitos clássicos de inibição das esterases acetilcolinesterase (AChE) e carboxilesterase (CbE). As atividades enzimáticas foram analisadas por espectrofotometria e os níveis de peroxidação lipídica por cromatografia líquida de alta performance (HPLC). A exposição de fêmeas de D. pagei ao diazinon por sete dias, levou á diminuição na atividade da GPx na concentração de 10 e 100 μg L-1 a 23°C, enquanto que nas brânquias foi observado diminuição da GST apenas na concentração de 10 μg L-1 em 23 °C. Quanto aos machos, os resultados apresentaram diminuição da GST na concentração de 100 μg L-1 tanto em 18 °C quanto em 28 °C. Também foi observado diminuição na atividade da GR na maior concentração (100 μg L-1) em 18 °C no hepatopâncreas deste mesmo sexo. Nas brânquias, este grupo apresentou diminuição da GPx em 18 °C na concentração de 100μg L-1 e aumento da GR na concentração de 10μg L-1 em 28 °C. Ao analisar a resposta apresentada pela G6PDH observou-se diminuição na atividade desta enzima na concentração de 100 μg L-1 em 18 e 23 °C no hepatopâncreas de machos expostos ao diazinon. Por outro lado, as fêmeas apresentaram aumento na maior concentração em 23 °C. No que diz respeito às brânquias de indivíduos expostos ao diazinon, pode-se observar diminuição na atividade da G6PDH em fêmeas na concentração de 100 μg L-1 a 28 °C. Por outro lado, observa-se aumento em sua atividade na maior concentração (100 μg L-1) a 23 °C. Machos não apresentaram alterações significantes da G6PDH nas brânquias. Quanto aos níveis de peroxidação lipídica, foi observado aumento apenas no hepatopâncreas de indivíduos expostos a este biocida a 23 °C, tanto nos machos quanto fêmeas apresentaram aumento nos níveis de MDA em 10 μg L-1 e apenas machos apresentaram aumento em 100 μg L-1. Em brânquias não foram observadas alterações significantes. Após exposição por sete dias ao diazinon pôde-se observar inibição da atividade da AChE em brânquias de machos expostos a 10 e 100 µg L-1 deste composto a 18 e 28 °C. No hepatopâncreas não foram observadas inibições significantes quanto a ação do composto. A CbE apresentou inibição em sua atividade no hepatopâncreas de machos nas concentração de 10µg L-1 em 18 °C e em ambas as concentrações em 23 e 28 °C. No que diz respeito às brânquias, houve inibição da CbE apenas em fêmeas expostas a 100µg L-1 do diazinon a 18 °C. Quanto ás respostas antioxidantes ao carbaril, em fêmeas foi observado aumento na atividade da GST na concentração de 100 μg L-1 a 18 °C no hepatopâncreas. Nessa mesma temperatura, foi observado aumento na atividade da GR na concentração de 10 μg L-1 e da GPx em 100 μg L-1. Por outro lado, nas brânquias foi observado aumento apenas na atividade da GR na concentração de 10 μg L-1 a 18 °C. Os machos expostos ao carbaril apresentaram aumento apenas da GST na concentração de 100 μg L-1 a 28 °C no hepatopâncreas. As brânquias de organismos expostos ao carbaril não apresentaram respostas significantes para as enzimas antioxidantes testadas. Quanto a G6PDH, houve aumento significante dessa enzima apenas na concentração de 10 μg L-1 a 18 °C em brânquias de fêmeas. No hepatopâncreas, houve diminuição nos níveis de MDA em machos expostos ao carbaril na concentração de 10 μg L-1 em 18 °C e nas duas concentrações (10 e 100 μg L-1) a 23 °C, ao passo que em fêmeas, neste órgão, foi observado aumento nos níveis de MDA apenas em 100 μg L-1 a 23 °C. No que diz respeito às brânquias, apenas fêmeas apresentaram aumento nos níveis de MDA na concentração de 100 μg L-1 em 18 e 28 °C. Após exposição de machos e fêmeas de D. pagei por sete dias ao carbaril pôde-se observar inibição da atividade da AChE e da CbE no hepatopâncreas apenas de fêmeas na maior concentração a 18 °C. De acordo com os resultados obtidos, pôde-se concluir que: Entre os biocidas testados, o carbaril se mostrou mais tóxico para fêmeas de D. pagei, uma vez que aumentos nos níveis de peroxidação lipídica foram observados com maior frequência nesse gênero. Além disso, as brânquias deste sexo demonstraram maior sensibilidade à ação do carbaril em relação ao hepatopâncreas e a combinação deste biocida a extremos de temperatura (18 e 28 °C) são mais prejudiciais a este sexo, pois aumentos nos níveis de peroxidação lipídica foram observadas com maior frequência nas brânquias nessas duas temperaturas. Nos machos a combinação entre o diazinon e a temperatura intermediária (23 °C) foi mais prejudicial no hepatopâncreas, uma vez que aumentos nos níveis de peroxidação lipídica foram observadas com maior frequência nesse órgão. Além disso, o aumento da temperatura aumentou a toxicidade do diazinon a CbE no hepatopâncreas de machos. Além do mais, a sensibilidade das brânquias de machos ao diazinon é maior em extremos de temperatura (18 e 28 °C). A temperatura influenciou tanto a atividade enzimática quanto a toxicidade dos biocidas diazinon e carbaril em D. pagei, uma vez que todas as enzimas testadas e os níveis de peroxidação lipídica apresentaram alterações relacionadas ao aumento da temperatura e a ação dos biocidas foi diferente nas três temperaturas testadas. Por fim, a espécie D. pagei demonstrou grande eficiência como organismo teste para a avaliação da presença de biocidas OP e CM em ambientes sob estresse térmico.
Global climate change has been highlighted in the field of aquatic toxicology due to the effects that changes in water temperature can perform on the responses of aquatic organisms to environmental contaminants. The body temperature of ectothermic organisms, such as crustaceans, is totally dependent on the environment temperature, so that increases in temperature directly affect the metabolism of these animals, accelerating the biochemical reactions and the intake of many water contaminants. In this study, we investigated the influence of three temperature ranges (18, 23 and 28°C) on toxicity of biocides diazinon (organophosphate) and carbaryl (carbamate) in the gills and hepatopancreas of males and females of the freshwater crab Dilocarcinus pagei. Through the analytical parameters of the antioxidant enzymes glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH), levels of lipid peroxidation through the formation of malondialdehyde (MDA) and the classical inhibition of the esterases acetylcholinesterase (AChE) and carboxylesterase (CbE). We measured the enzyme activities by spectrophotometry and the levels of lipid peroxidation by high performance liquid chromatography (HPLC). The exposure of D. pagei females to diazinon for seven days resulted in decrease in GPx activity in 10 and 100 µg/L of concentration at 23°C. In the gills, we observed reduction of GST only in the concentration of 10 µg/L at 23°C. In males, the results showed decrease in GST activity in the concentration of 100 µg/L at both temperatures (18 and 28°C). We also observed decrease in GR activity at the highest concentration (100 µg/L) at 18°C in the hepatopancreas of this gender. In the gills, this group showed decrease in GPx at 18°C in a concentration of 100 μg/L and GR increased in 10 µg/L of concentration at 28°C. According to G6PDH response, we observed decrease at a concentration of 100 µg/L on 18 and 23°C in the hepatopancreas of males exposed to diazinon. On the other hand, females showed increase in the highest concentration at 23°C. With regard to the gills of individuals exposed to diazinon, we observed decrease of G6PDH activity in females at the concentration of 100 µg/L at 28°C. On the other hand, we observed increase in this enzyme activity at the highest concentration (100 µg/L) at 23°C. Males showed no significant changes of G6PDH in the gills. The levels of lipid peroxidation increased only in hepatopancreas of individuals exposed to this biocide to 23°C, where both males and females showed increase in MDA levels in 10 µg/L and only males showed increase in 100 µg/L. In the gills no significant changes were observed. After exposure of seven days to diazinon we observed AChE inhibition in gills of males exposed to 10 and 100 µg/L of this chemical at 18 and 28˚C. In hepatopancreas no significant inhibition were observed. CbE showed inhibition in the hepatopancreas of males in the concentration of 10 µg/L at 18˚C and in both concentrations at 23 and 28˚C. With regard to the gills, there was inhibition of CbE only in females exposed to 100 μg/L of diazinon at 18°C. Concerning to the antioxidant response to carbaryl in females we observed increase in GST activity in a concentration of 100 µg/L at 18°C in the hepatopancreas. In this same temperature, there was increase in GR activity at a concentration of 10 µg/L and GPx in 100 µg/L. On the other hand, we observed increase in GR activity only in the gills in the concentration of 10 µg/L at 18°C. The males exposed to carbaryl showed increase of GST in 100 µg/L at 28°C in the hepatopancreas. The gills of organisms exposed to carbaryl showed no significant responses to the tested antioxidant enzymes. With regard to the G6PDH, we observed a significant increase in the concentration of 10 µg/L at 18°C only in females gills. The levels of MDA decreased in the hepatopancreas of males exposed to carbaryl in a concentration of 10 µg/L at 18°C and in both concentrations (10 µg/L and 100 µg/L) at 23°C. In females, we observed increase in MDA levels only in 100 µg/L at 23°C. In the gills, only females showed increase in MDA levels at the concentration of 100 µg/L at 18 and 28°C. After exposure of D. pagei males and females for seven days to carbaryl we observed inhibition of AChE and CbE only in hepatopâncreas of females in the highest concentration to 18°C. According to the results, we can conclude that: Among the tested biocides, carbaryl was more toxic to females as increases in lipid peroxidation levels were observed more frequently in this gender. Moreover, females gills showed greater sensitivity to carbaryl compared to the hepatopancreas and the combination of this biocide to extremes of temperature (18 and 28°C) are more detrimental to this gender as increases in lipid peroxidation levels were observed more often in the gills at these two temperatures. In males, the combination of diazinon and the intermediate temperature (23°C) was more damaging in the hepatopancreas, as increases in lipid peroxidation levels were observed more frequently in this organ. Furthermore, the increase in temperature increased the toxicity of diazinon to CbE in the hepatopancreas of males. Moreover, the sensitivity of the male gills to diazinon is higher in extreme temperatures (18 and 28°C). The temperature influences both the enzymatic activity and the toxicity of biocides diazinon and carbaryl in D. pagei, since all the tested enzymes and lipid peroxidation levels showed changes related to increase in the temperature and the action of biocides was different at the three temperatures tested. Finally, the species D. pagei demonstrated great effectiveness as a test organism for evaluating the presence of OP and CM biocides in environments under heat stress.
Global climate change has been highlighted in the field of aquatic toxicology due to the effects that changes in water temperature can perform on the responses of aquatic organisms to environmental contaminants. The body temperature of ectothermic organisms, such as crustaceans, is totally dependent on the environment temperature, so that increases in temperature directly affect the metabolism of these animals, accelerating the biochemical reactions and the intake of many water contaminants. In this study, we investigated the influence of three temperature ranges (18, 23 and 28°C) on toxicity of biocides diazinon (organophosphate) and carbaryl (carbamate) in the gills and hepatopancreas of males and females of the freshwater crab Dilocarcinus pagei. Through the analytical parameters of the antioxidant enzymes glutathione S-transferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH), levels of lipid peroxidation through the formation of malondialdehyde (MDA) and the classical inhibition of the esterases acetylcholinesterase (AChE) and carboxylesterase (CbE). We measured the enzyme activities by spectrophotometry and the levels of lipid peroxidation by high performance liquid chromatography (HPLC). The exposure of D. pagei females to diazinon for seven days resulted in decrease in GPx activity in 10 and 100 µg/L of concentration at 23°C. In the gills, we observed reduction of GST only in the concentration of 10 µg/L at 23°C. In males, the results showed decrease in GST activity in the concentration of 100 µg/L at both temperatures (18 and 28°C). We also observed decrease in GR activity at the highest concentration (100 µg/L) at 18°C in the hepatopancreas of this gender. In the gills, this group showed decrease in GPx at 18°C in a concentration of 100 μg/L and GR increased in 10 µg/L of concentration at 28°C. According to G6PDH response, we observed decrease at a concentration of 100 µg/L on 18 and 23°C in the hepatopancreas of males exposed to diazinon. On the other hand, females showed increase in the highest concentration at 23°C. With regard to the gills of individuals exposed to diazinon, we observed decrease of G6PDH activity in females at the concentration of 100 µg/L at 28°C. On the other hand, we observed increase in this enzyme activity at the highest concentration (100 µg/L) at 23°C. Males showed no significant changes of G6PDH in the gills. The levels of lipid peroxidation increased only in hepatopancreas of individuals exposed to this biocide to 23°C, where both males and females showed increase in MDA levels in 10 µg/L and only males showed increase in 100 µg/L. In the gills no significant changes were observed. After exposure of seven days to diazinon we observed AChE inhibition in gills of males exposed to 10 and 100 µg/L of this chemical at 18 and 28˚C. In hepatopancreas no significant inhibition were observed. CbE showed inhibition in the hepatopancreas of males in the concentration of 10 µg/L at 18˚C and in both concentrations at 23 and 28˚C. With regard to the gills, there was inhibition of CbE only in females exposed to 100 μg/L of diazinon at 18°C. Concerning to the antioxidant response to carbaryl in females we observed increase in GST activity in a concentration of 100 µg/L at 18°C in the hepatopancreas. In this same temperature, there was increase in GR activity at a concentration of 10 µg/L and GPx in 100 µg/L. On the other hand, we observed increase in GR activity only in the gills in the concentration of 10 µg/L at 18°C. The males exposed to carbaryl showed increase of GST in 100 µg/L at 28°C in the hepatopancreas. The gills of organisms exposed to carbaryl showed no significant responses to the tested antioxidant enzymes. With regard to the G6PDH, we observed a significant increase in the concentration of 10 µg/L at 18°C only in females gills. The levels of MDA decreased in the hepatopancreas of males exposed to carbaryl in a concentration of 10 µg/L at 18°C and in both concentrations (10 µg/L and 100 µg/L) at 23°C. In females, we observed increase in MDA levels only in 100 µg/L at 23°C. In the gills, only females showed increase in MDA levels at the concentration of 100 µg/L at 18 and 28°C. After exposure of D. pagei males and females for seven days to carbaryl we observed inhibition of AChE and CbE only in hepatopâncreas of females in the highest concentration to 18°C. According to the results, we can conclude that: Among the tested biocides, carbaryl was more toxic to females as increases in lipid peroxidation levels were observed more frequently in this gender. Moreover, females gills showed greater sensitivity to carbaryl compared to the hepatopancreas and the combination of this biocide to extremes of temperature (18 and 28°C) are more detrimental to this gender as increases in lipid peroxidation levels were observed more often in the gills at these two temperatures. In males, the combination of diazinon and the intermediate temperature (23°C) was more damaging in the hepatopancreas, as increases in lipid peroxidation levels were observed more frequently in this organ. Furthermore, the increase in temperature increased the toxicity of diazinon to CbE in the hepatopancreas of males. Moreover, the sensitivity of the male gills to diazinon is higher in extreme temperatures (18 and 28°C). The temperature influences both the enzymatic activity and the toxicity of biocides diazinon and carbaryl in D. pagei, since all the tested enzymes and lipid peroxidation levels showed changes related to increase in the temperature and the action of biocides was different at the three temperatures tested. Finally, the species D. pagei demonstrated great effectiveness as a test organism for evaluating the presence of OP and CM biocides in environments under heat stress.
Descrição
Palavras-chave
Caranguejo dulcícola, Organofosforado, Carbamato, Estresse oxidativo, Inibição esterásica, Aquecimento global, Freshwater crab, Organophosphate, Carbamate, Oxidative stress, Esterase inhibition, Global warming