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1.
Chemosphere ; 241: 125091, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683442

RESUMO

Soil columns were collected from a blueberry field, and insecticide solutions were allowed to leach through these columns. Insecticides from four different chemical classes were applied at two different rates: the concentration at which the insecticides wash off blueberries under rainfall conditions and the labeled field rate at which they are sprayed. The soil columns were divided into thirds; top, middle and bottom. Soil bioassays using Eisenia foetida Savigny, as an indicator species, were set up to determine the toxicity of the insecticides at a top, middle and bottom layer of the soil column. The mass of E. foetida was also measured after the bioassay experiment was completed. The concentrations at which insecticides wash-off of blueberries from rainfall were not lethal to E. foetida. In order to support mortality data, insecticide residues were quantified in the soil layers for each insecticide. Under field rate leaching conditions, carbaryl showed the high levels of toxicity in the top and middle layers of soil suggesting that it has the highest risk to organisms from leaching. This study will help blueberry growers make informed decisions about insecticide use, which can help minimize contamination of the environment.


Assuntos
Mirtilos Azuis (Planta)/crescimento & desenvolvimento , Inseticidas/análise , Inseticidas/toxicidade , Oligoquetos/efeitos dos fármacos , Poluentes do Solo/toxicidade , Animais , Carbaril/análise , Carbaril/toxicidade , Produtos Agrícolas/crescimento & desenvolvimento , Ecotoxicologia , Michigan , Resíduos de Praguicidas/análise , Chuva , Solo/química , Poluentes do Solo/análise
2.
Chemosphere ; 235: 1022-1029, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31561291

RESUMO

Chemical exposure during the early life stages of development may have long lasting effects on organisms that are rarely studied. The present work intended to evaluate the effect of embryonic exposure to the pesticide carbaryl on adult fish behavior. Zebrafish (Danio rerio) embryos were exposed, for 4 days, to sublethal concentrations of carbaryl (0.01, 0.1 and 1.0 mg/L) plus a control and then kept in standard cultivation conditions until adulthood. A battery of behavioral tests was then performed to assess anxiety-like behavior (locomotor activity, thigmotaxis and novel tank diving test), social behavior, and feeding. Developmental exposure of zebrafish to sublethal concentrations of carbaryl produced important behavioral alterations in the adulthood. Main effects included decreased locomotion/hypoactivity (increase in slow movements and decrease of medium and rapid movements), especially in the light periods. Moreover, spatial pattern also changed: while during dark periods control fish increased activity in the outer zone of the tank, this was not observed in exposed fish. Overall, this demonstrated the importance of life stage exposure, clearly demonstrating long lasting effects of a (chemical) stress event at embryonic stages. This data supports the need of considering this scenario in environmental risk evaluations. Further work should focus on the mechanistic effects of developmental disruption responsible for the effects observed.


Assuntos
Comportamento Animal/efeitos dos fármacos , Carbaril/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Inseticidas/toxicidade , Peixe-Zebra/embriologia , Animais , Locomoção/efeitos dos fármacos
3.
Biomarkers ; 24(7): 666-676, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31368361

RESUMO

Synergy occurs when chemicals give pronounced effect on combination in contrast to their individual effect. The objective of this study was to investigate the synergistic effect of pesticides carbaryl (C) and methyl parathion (MP) on oxidative stress biomarkers viz catalase (CAT), glutathione reductase (GSSG-R) including different enzymes like lactate dehydrogenase (LDH), succinate dehydrogenase (SDH) and acetyl cholinesterase (AChE) in different tissues of carps Catla catla. Fishes were exposed to 6.25 mg/L of MP and 2.3 mg/L of C in mixture (one-third of LC50 value). CAT and GSSG-R were studied in gills, brain, liver and muscle of carp were found to be elevated significantly (p < 0.005). LDH activity increased significantly (p < 0.005) in synergistic group, there was a seven-fold (748%) increase in LDH activity in muscle compared to individual studies with same pesticides. Contrary to LDH, sudden decrease in SDH activity was accounted. Significant (p < 0.005) decrease in AChE activity after initial 24 h was remarkable addressing to the shift in neurotransmission pathway in organism. Significant increase was observed in activity of CAT and GSSG-R in all tissues compared to control fishes in individual as well as synergistic (MP + C) group suggesting that CAT and GSSG-R can be a potential biomarker of oxidative stress when studied in combination.


Assuntos
Catalase/metabolismo , Glutationa Redutase/metabolismo , Praguicidas/toxicidade , Animais , Biomarcadores/metabolismo , Carbaril/toxicidade , Carpas , Sinergismo Farmacológico , Peixes , Metil Paration/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Distribuição Tecidual
4.
J Environ Sci Health B ; 54(11): 883-891, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31311415

RESUMO

The characterization of soluble cholinesterases (ChEs) together with carboxylesterases (CEs) in Ficopomatus enigmaticus as suitable biomarkers of neurotoxicity was the main aim of this study. ChEs of F. enigmaticus were characterized considering enzymatic activity, substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (Km and Vmax) and in vitro response to model inhibitors (eserine hemisulfate, iso-OMPA, BW284C51), and carbamates (carbofuran, methomyl, aldicarb, and carbaryl). CEs were characterized based on enzymatic activity, kinetic parameters and in vitro response to carbamates (carbofuran, methomyl, aldicarb, and carbaryl). Results showed that cholinesterases from F. enigmaticus showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was not hydrolyzed differently from other Annelida species. CE activity was in the same range of cholinesterase activity with acetylthiocholine as substrate; the enzyme activity showed high affinity for the substrate p-nytrophenyl butyrate. Carbamates inhibited ChE activity with propionylthiocholine as substrate to a higher extent than with acetylthiocoline. Also CE activity was inhibited by all tested carbamates except carbaryl. In vitro data highlighted the presence of active forms of ChEs and CEs in F. enigmaticus that could potentially be inhibited by pesticides at environmentally relevant concentration.


Assuntos
Anelídeos/enzimologia , Inibidores da Colinesterase/toxicidade , Colinesterases/química , Neurotoxinas/toxicidade , Animais , Anelídeos/efeitos dos fármacos , Biomarcadores/química , Carbamatos/química , Carbaril/química , Carbaril/toxicidade , Carbofurano/química , Carbofurano/toxicidade , Hidrolases de Éster Carboxílico/antagonistas & inibidores , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Inibidores da Colinesterase/química , Colinesterases/metabolismo , Cinética , Metomil/química , Metomil/toxicidade , Neurotoxinas/química
5.
Environ Toxicol Pharmacol ; 71: 103217, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31284173

RESUMO

Ultrastructural and histopathological reponses in the organs of living organisms are important and useful tools to determine the health condition and the effects of pollutants, such as pesticides, on the organisms. The aim of this study is to determine possible histopathological, cytopathological and ultrastructural alterations in gills of Oreochromis niloticus individuals exposed to 850 µg/L carbaryl standart at 7th, 14th and 21st days with light and electron microscopes. The fish were exposed to carbaryl for 21 days and the histopatological, ultrastructural and cytopathological alterations occuring in the gill tissues of organisms were determined by light, Scanning and Transmission Electron Microscopes (SEM and TEM). At the end of the study, it was observed that carbaryl caused both histopathological and cytopathological changes in the gills of O. niloticus. It has been determined that the most of the pathological changes in the exposed organisms are the metabolic defence reactions.


Assuntos
Carbaril/toxicidade , Ciclídeos , Células Epiteliais/efeitos dos fármacos , Brânquias/efeitos dos fármacos , Inseticidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Células Epiteliais/ultraestrutura , Brânquias/ultraestrutura , Hiperplasia , Microscopia Eletroquímica de Varredura , Microscopia Eletrônica de Transmissão , Membrana Mucosa/efeitos dos fármacos , Membrana Mucosa/ultraestrutura
6.
Ecotoxicol Environ Saf ; 173: 482-493, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30802737

RESUMO

Cholinesterases are frequent targets for toxic effects, namely by insecticides derived from phosphoric and carbamic acids. This effects allows the use of cholinesterase inhibition as a biomarker for contamination of aquatic environments by these specific chemical agents. However, cholinesterases are differently responsive to environmental contaminants, according to their different forms and locations. In addition, cholinesterases seem also to be inhibited by metals, so their use as an environmental criterion requires the prior characterization of their specific forms in each species and tissues, and the study of their sensitivity. The objective of this study was to characterize the cholinesterase isoenzymes present in the brain and dorsal muscle of three tropical fish species, namely Phalloceros harpagos (Lucinda, 2008), Pterygoplichthys pardalis (Castelnau, 1855) and Astyanax altiparanae (Garutti and Britski, 2000). In vitro assays were conducted to quantify the effect of pesticides (dimethoate and carbaryl) and metals (lead and copper) on cholinesterases activity. Although acetylcholinesterase seems to be the most prevalent and abundant form, as commonly described in vertebrates, the here-obtained results showed that three cholinesterase isoenzymes occur in tissues of the three fish species. In addition, the pesticide carbaryl caused a stronger inhibition than dimethoate. Copper caused a significantly higher cholinesterasic inhibition than lead, which is also in line with most results concerning the anticholinesterasic effects by these metals. The here obtained results allowed to conclude that acetylcholinesterase is the predominant form in all tissues from the three analyzed species. In addition, cholinesterases of these three fish were responsive to common environmental contaminants, namely metals and pesticides, similarly to what was already described for fish of temperate areas. This allows using the here proposed fish species in environmental studies for the assessment of the presence of neurotoxicants under neotropical conditions.


Assuntos
Peixes-Gato/metabolismo , Inibidores da Colinesterase/toxicidade , Cobre/toxicidade , Ciprinodontiformes/metabolismo , Chumbo/toxicidade , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Carbaril/toxicidade , Colinesterases/metabolismo , Dimetoato/toxicidade , Feminino , Proteínas de Peixes/metabolismo , Masculino , Músculos/efeitos dos fármacos , Músculos/enzimologia
7.
Environ Toxicol Chem ; 37(10): 2699-2704, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30035389

RESUMO

In areas with heavy pesticide use, it is easy to attribute population declines to environmental contamination. The Blanchard's cricket frogs (Acris blanchardi) is an amphibian experiencing declines and range contractions across its distribution in the Midwest Corn Belt (USA). Experimental studies suggest that cricket frogs are sensitive to pesticides, but there are few studies examining this species' susceptibility to contaminants in realistic environments or comparing relative impacts with other anuran species. I reared 3 summer breeding anurans in outdoor mesocosms posthatching through metamorphosis to examine the effects of 2 insecticides (imidacloprid and carbaryl) and 1 herbicide (glyphosate with polyoxyethylene tallow amine) on larval development and metamorphosis. Cricket frogs were positively affected by insecticide exposure, likely a result of changes in the food web that increased food abundance. However, metamorphosis of green frogs (Lithobates clamitans) and gray tree frogs (Hyla chrysoscelis) appeared unaffected by pesticide exposure. The results of the present study suggest that the impacts of pesticides alone are unlikely to have population-level impacts for the anurans examined. Environ Toxicol Chem 2018;37:2699-2704. © 2018 SETAC.


Assuntos
Anuros/crescimento & desenvolvimento , Ecossistema , Praguicidas/toxicidade , Rana clamitans/crescimento & desenvolvimento , Análise de Variância , Animais , Carbaril/toxicidade , Exposição Ambiental/análise , Glicina/análogos & derivados , Glicina/toxicidade , Herbicidas/toxicidade , Inseticidas/toxicidade , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Polietilenoglicóis/toxicidade , Especificidade da Espécie , Fatores de Tempo
8.
Environ Sci Pollut Res Int ; 25(25): 24917-24922, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29931639

RESUMO

This study describes the histopathological effects of carbaryl in the spleen of Levantine frog, Pelophylax bedriage. Due to its primary role in immune system, it is important to research the toxic effects of pesticides, which play an important role in environmental pollution, on spleen. To that end, adult frogs were exposed to carbaryl for 96 h. Experimental groups contained low dose, (0.05 mg/g), medium dose (0.1 mg/g) and high dose (0.2 mg/g). After following exposure to carbaryl, the frogs were euthanised and dissected. In low-dose group, there were no important changes in spleen tissue. In medium-dose group, prominence in haemorrhage just below the capsule and an increase in the melanomacrophage number were determined. In high-dose group, in addition to increases in the melanomacrophages, separations in capsule, haemorrhage below capsule and within splenic tissue, sinusoidal enlargement, congestion in dilated sinusoid, hypertrophic plasma cells and fibrosis were determined as important histological lesions in exposed frogs. This study clearly showed that carbaryl caused important histopathological damages in splenic tissue of Pelophylax bedriagae. In view of these findings, it can be said that this insecticide has the capacity to disrupt spleen' functions.


Assuntos
Carbaril/toxicidade , Poluentes Ambientais/toxicidade , Inseticidas/toxicidade , Baço/efeitos dos fármacos , Animais , Anuros , Relação Dose-Resposta a Droga , Baço/patologia
9.
Environ Toxicol Chem ; 37(8): 2188-2197, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29786147

RESUMO

Although the paradigm for increased tolerance to pesticides has been by selection on constitutive (naïve) traits, recent research has shown it can also occur through phenotypic plasticity. However, the time period in which induction can occur, the duration of induced tolerance, and the influence of multiple induction events remain unknown. We hypothesized that the induction of increased pesticide tolerance is limited to early sensitive periods, the magnitude of induced tolerance depends on the number of exposures, and the retention of induced tolerance depends on the time elapsed after an exposure and the number of exposures. To test these hypotheses, we exposed wood frog tadpoles to either a no-carbaryl control (water) or 0.5 mg/L carbaryl at 4 time periods, and later tested their tolerance to carbaryl using time-to-death assays. We discovered that tadpoles induced increased tolerance early and midway but not late in our experiment and their constitutive tolerance increased with age. We found no difference in the magnitude of induced tolerance after a single or 2 exposures. Finally, induced pesticide tolerance was reversed within 6 d but was retained only when tadpoles experienced all 4 consecutive exposures. Phenotypic plasticity provides an immediate response for sensitive amphibian larvae to early pesticide exposures and reduces phenotypic mismatches in aquatic environments contaminated by agrochemicals. Environ Toxicol Chem 2018;37:2188-2197. © 2018 SETAC.


Assuntos
Exposição Ambiental/análise , Inseticidas/toxicidade , Ranidae/fisiologia , Animais , Carbaril/toxicidade , Larva/efeitos dos fármacos , Praguicidas/toxicidade , Fatores de Tempo
10.
Aquat Toxicol ; 199: 276-284, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29689476

RESUMO

Carbamate insecticides such as carbaryl and organophosphates such as azinphos-methyl share the ability to inhibit the activity of B-esterases. This study aimed to (1) assess the inhibitory effects of carbaryl on B-esterase activity in soft tissues and hemolymph of Planorbarius corneus; (2) establish whether binary mixtures of carbaryl and azinphos-methyl depart or not from a model of concentration addition on the inhibition of cholinesterase activity; (3) determine the bioconcentration and elimination of the pesticides. The results showed that exposure of gastropods to increasing concentrations of carbaryl (0.1-5 mg L-1) for 48 h inhibited cholinesterase activity in a concentration-dependent manner, with an EC50 of 1.4 ±â€¯0.3 mg L-1 and 1.2 ±â€¯0.1 mg L-1 for soft tissue and hemolymph, respectively. Carboxylesterase activity, measured with the substrates p-nitrophenyl butyrate and p-nitrophenyl acetate, was between 2.3 and 25 times more sensitive to carbaryl inhibition than cholinesterase activity. Binary mixtures corresponding to 0.5 EC50 carbaryl + 0.5 EC50 azinphos-methyl and 0.75 EC50 carbaryl + 0.75 EC50 azinphos-methyl produced inhibitions of cholinesterase activity similar to those of individual pesticides, following a model of concentration addition. Bioconcentration was analyzed using a one-compartment model. The absorption kinetics (k1) for both pesticides alone (1.4 mg L-1 of carbaryl or 1.8 mg L-1 of azinphos-methyl) or mixed (1.4 mg L-1 of carbaryl + 1.8 mg L-1 of azinphos-methyl) were similar. The elimination kinetics ratio (k2) estimated for the pesticides alone or in the mixtures showed that carbaryl was eliminated 3.5 times faster than azinphos-methyl. These results suggest that exposure of Planorbarius corneus to binary mixtures of carbaryl and azinphos-methyl for 48 h follow a concentration addition model on inhibition of cholinesterase activity and that the pesticide mixtures do not change the toxicokinetic parameters of the parent compounds.


Assuntos
Azinfos-Metil/toxicidade , Carbaril/farmacocinética , Carbaril/toxicidade , Água Doce , Gastrópodes/efeitos dos fármacos , Animais , Carboxilesterase/metabolismo , Colinesterases/metabolismo , Gastrópodes/enzimologia , Hemolinfa/metabolismo , Cinética , Toxicocinética , Poluentes Químicos da Água/toxicidade
11.
Aquat Toxicol ; 196: 79-89, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29358113

RESUMO

The brine shrimp Artemia was used as a model organism to test toxicity of several neuroactive pesticides (chlorpyrifos (CLP), chlorpyrifos oxon (CLP ox), diazinon (DZN), carbaryl (CBR)) following exposure to far below than lethal doses. Cysts were exposed to the pesticides in order to test a scenario similar to actual coastal environment contamination, by analyzing different responses. Cysts were rehydrated in water containing the pesticides at concentrations ranging from 10-11 to 10-5 M, for 72, 96 and 192 h, respectively. For these exposure times, morpho-functional and biochemical parameters, such as hatching speed and viability were investigated in the larvae together with cholinesterase (ChE) activity quantification and histochemical localization. Finally, ChE inhibition was also compared with conventional selective ChE inhibitors. Results showed that CLP ox and CBR caused a significant dose-dependent decrease in hatching speed, followed by high percentages of larval death, while CLP and DZN were responsible for irregular hatching patterns. In addition, the pesticides mostly caused larval death some days post-hatching, whereas this effect was negligible for the specific ChE inhibitors, suggesting that part of pesticide toxicity may be due to molecules other than the primary target. ChE activity was observed in the protocerebrum lobes, linked to the development of pair eyes. Such activity was inhibited in larvae exposed to all pesticides. When compared to conventional selective inhibitors of ChE activities, this inhibition demonstrated that the selected pesticides mainly affect acetylcholinesterase and, to a lesser extent, pseudocholinesterases. In conclusion, the brine shrimp is a good model to test the environmental toxicity of long term exposure to cholinergic pesticides, since changes in hatching speed, viability and ChE activity were observed.


Assuntos
Artemia/efeitos dos fármacos , Colinesterases/metabolismo , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Artemia/crescimento & desenvolvimento , Artemia/metabolismo , Carbaril/toxicidade , Clorpirifos/toxicidade , Inibidores da Colinesterase/toxicidade , Diazinon/toxicidade , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Dose Letal Mediana
12.
Pestic Biochem Physiol ; 143: 81-89, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29183615

RESUMO

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Lividae) transmits the Candidatus Liberibacter asiaticus, which causes citrus greening disease or Huanglongbing, (HLB). To date, there is no efficient cure for HLB disease and the control of D. citri using insecticides became the most important tools for the management of HLB. However, the extensive use of insecticides could increase D. citri resistance to these insecticides. The objective of this study was to investigate the effect of RNA interference of acetylcholinesterase (AChE) on the mortality and susceptibility of D. citri to the four major insecticides used in Florida. In this study, we used a consensus sequence derived from the two AChE genes and cholinesterase 2-like (ChE-2-like) gene to target all of the three genes. Treatment with dsRNA-AChE increased the mortality percentages of both nymphs and adults of D. citri. The mortality percentage increased with the increase in the concentration of applied dsRNA-AChE, and the highest mortality (> 60%) was observed at the highest applied concentration (125ng/µl). Treatments of nymphs or adults with dsRNA-AChE down-regulated the expression of the three targeted genes of D. citri. Silencing of AChE and ChE in D. citri nymphs increased the susceptibility of emerged adults to chlorpyrifos and carbaryl, which act as AChE inhibitors. However, treatment with dsRNA-AChE did not increase the susceptibility of emerged adults to imidacloprid, which acts as an agonist of nicotinic acetylcholine receptors. In the same manner, treatment of adults with dsRNA-AChE increased their susceptibility to chlorpyrifos and carbaryl, but did not affect their susceptibility to imidacloprid. The ANOVA did not show any significant increase in susceptibility of D. citri adults to fenpropathrin after treatment with dsRNA-AChE, either as nymphs or as adults. However, simple linear regression showed that treatment with dsRNA-AChE increased D. citri susceptibility to fenpropathrin, which indicated that AChE could be involved in the metabolism of fenpropathrin. Our results indicated that silencing of AChE and ChE genes in D. citri to increase its susceptibility to insecticides could be a promising tool for the control of this important vector.


Assuntos
Colinesterases/genética , Hemípteros/efeitos dos fármacos , Proteínas de Insetos/genética , Resistência a Inseticidas/genética , Inseticidas/toxicidade , Interferência de RNA , Animais , Carbaril/toxicidade , Clorpirifos/toxicidade , Expressão Gênica/efeitos dos fármacos , Hemípteros/genética , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Piretrinas/toxicidade
13.
Pestic Biochem Physiol ; 138: 43-50, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28456303

RESUMO

Pesticide exposure can induce oxidative stress and cause changes to antioxidant enzymes in living organisms. In the present study, the effects of phoxim (an organophosphorus insecticide) and carbaryl (a carbamate insecticide) on antioxidant enzyme activity and gene expression were investigated in the model organism Caenorhabditis elegans. The results show that phoxim exposure can induce superoxide dismutase (SOD) and catalase (CAT) activities and decrease glutathione peroxidase (GPx) activity at lower concentrations. The expression levels of sod-3, sod-5, ctl-1, gpx-6, and gpx-8 were up-regulated after treatment with phoxim. The mRNA expression levels of sod-5, ctl-1 and gpx-6 were increased approximately 70-, 170- and 130-fold, respectively, in the 0.25mM treatment group compared to the control group. Carbaryl exposure decreased SOD activity and induced CAT and GPx activities. The addition of carbaryl up-regulated the expression of sod-5, ctl-1, ctl-3 and gpx-8. Specifically, ctl-1 expression increased approximately 10-fold, and gpx-8 expression increased <30-fold in the 0.5mM treatment group relative to the control group. The transcript level of sod-5 increased >20-fold, and ctl-3 increased approximately 10-fold in the 1mM treatment group. The functions of the antioxidant enzymes during oxidative stress caused by the two insecticides were investigated using deletion mutants. The LC50 values phoxim for the of sod-3 (tm760), sod-5 (tm1146), ctl-1 (ok1242), ctl-3 (ok2042) and gpx-8 (tm2108) mutant strains were lower than those observed for the N2 strain. The LC50 values of carbaryl for the ctl-1 (ok1242), ctl-3 (ok2042) and gpx-6 (tm2535) deletion mutant strains decreased in comparison to the N2 strain. The results suggest that these two insecticides caused oxidative stress and changed altered the antioxidant enzyme activities and their gene expressions in C. elegans. The sod-3, sod-5, ctl-1, ctl-3, gpx-6, and gpx-8 encoding enzymes may play roles in defending cells from oxidative stress caused by these two insecticides.


Assuntos
Antioxidantes/metabolismo , Caenorhabditis elegans/efeitos dos fármacos , Carbaril/toxicidade , Inseticidas/toxicidade , Compostos Organotiofosforados/toxicidade , Estresse Fisiológico/efeitos dos fármacos , Animais , Caenorhabditis elegans/enzimologia , Regulação Enzimológica da Expressão Gênica
14.
Aquat Toxicol ; 188: 72-79, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28460306

RESUMO

During the last years, a carbaryl insecticide was extensively applied in the valley of Río Negro and Neuquén, North Patagonia Argentina, to manage codling moths (Cydia pomonella), the main pest of pear and apple trees. In this study carbaryl susceptibility and B-esterase activity from both insecticide-exposed and non-exposed field populations of amphipods Hyalella curvispina were studied. Two subpopulations, one susceptible to carbaryl (LC50=213±7.5µg/L carbaryl) and one resistant to it (LC50=14,663±2379µg/L carbaryl), were found in the agricultural area selected in this study. Both populations were, in turn, more resistant to carbaryl than the population from a pristine area (LC50=11.31±2.27µg/L carbaryl). The in vivo 48h-IC50 values for cholinesterase (ChE) were close to the corresponding 48h-LC50 values as determined for the non-exposed population (IC50=7.16±0.86µg/L carbaryl) and for the susceptible subpopulation from the insecticide-exposed site (IC50=193±99µg/L carbaryl). Carbaryl exposure of the amphipods from the agricultural area mentioned above produced a significant decrease of carboxylesterase (CabE) activity, at a sublethal concentration (10µg/L) that was not able to significantly inhibit ChE, thereby showing a protective role of CabE and its usefulness as early biomarker. However, at lethal concentrations the inhibition of ChE activity was higher than that of CabE. On the other hand, CabE of amphipods from the pristine site was less sensitive to carbaryl than ChE, suggesting a different participation of CabE in ChE protection in the susceptible population of H. curvispina. Pulse exposure to carbaryl for 2h caused a significant inhibition of ChE in amphipods from both populations, with a fast recovery as expected for a carbamate insecticide. In conclusion, we proved that amphipods from the said agricultural area have developed resistance to carbaryl and showed the presence of two subpopulations with a different response to the insecticide. Moreover, these results reinforce the use of ChE together with CabE inhibition as indicators of carbamate exposure in H. curvispina.


Assuntos
Anfípodes/efeitos dos fármacos , Carbaril/toxicidade , Carboxilesterase/metabolismo , Colinesterases/metabolismo , Inseticidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Argentina , Biomarcadores/metabolismo , Carboxilesterase/antagonistas & inibidores
15.
Environ Pollut ; 224: 615-621, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28259584

RESUMO

Few studies in developmental toxicology have focused on whether early life contaminant exposure affects future susceptibility. Investigations in frogs suggested that early life exposure to a pesticide resulted in higher tolerance to a subsequent challenge. This led to the hypothesis that early-life stage exposures can alter phenotypically plastic traits during development, resulting in induced tolerance. Here, we used Gulf killifish (Fundulus grandis) to test the role of detoxification pathway priming in this inducible tolerance. In frogs, the induced tolerance is present five days after the end of the pre-exposure, but absent after a month. We show that a pre-exposure early in life with carbaryl, induces the activity of cytochrome P450 1A (CYP1A) and increases the ability of pre-exposed groups to metabolize carbaryl, likely because of activation of the aryl hydrocarbon receptor (AHR) pathway. Embryos pre-exposed to carbaryl had a 350-500% increase in CYP1A activity, threefold greater capacity to metabolize carbaryl and were more tolerant to a lethal challenge five days after the end of pre-exposure. However, ten days later the differences in CYP1A activity, metabolic capacity and tolerance between pre-exposed and control groups were no longer present. Thus, we conclude that the increase in tolerance observed in pre-exposed fish embryos was due to the activation of the AHR and other metabolic pathways, resulting in a prolonged increase in biotransformation capacity. This allowed individuals to more efficiently deal with subsequent chemical challenges for a short period after the initial pre-exposure. However, this induced tolerance was only short-lived due to the recycling of biotransformation enzymes in the cells as part of general cellular protein maintenance. These findings suggest that induced tolerance was likely due to induction of defense mechanisms during the duration of response to the original stressor, rather than a more permanent change in their ability to respond to future challenges.


Assuntos
Carbaril/toxicidade , Fundulidae/metabolismo , Estágios do Ciclo de Vida/efeitos dos fármacos , Praguicidas/metabolismo , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Texas
16.
Sci Rep ; 7: 44565, 2017 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-28300212

RESUMO

Container aquatic habitats support a specialized community of macroinvertebrates (e.g. mosquitoes) that feed on microbial communities associated with decaying organic matter. These aquatic habitats are often embedded within and around agricultural lands and are frequently exposed to pesticides. We used a microcosm approach to examine the single and combined effects of two herbicides (atrazine, glyphosate), and three insecticides (malathion, carbaryl, permethrin) on microbial communities of container aquatic habitats. MiSeq sequencing of the V4 region of both bacterial and archaeal 16S rRNA gene was used to characterize the microbial communities of indoor microcosms that were either exposed to each pesticide alone, a mix of herbicides, a mix of insecticides, or a mix of all five insecticides. Individual insecticides but not herbicides reduced the microbial diversity and richness and two insecticides, carbaryl and permethrin, also altered the microbial community structure. A mixture of herbicides had no effect on microbial diversity or structure but a mixture of insecticides or all five pesticides reduced microbial diversity and altered the community structure. These findings suggest that exposure of aquatic ecosystems to individual pesticides or their mixtures can disrupt aquatic microbial communities and there is need to decipher how these changes affect resident macroinvertebrate communities.


Assuntos
Organismos Aquáticos/genética , Culicidae/efeitos dos fármacos , Variação Genética/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Agricultura , Animais , Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/microbiologia , Atrazina/toxicidade , Carbaril/toxicidade , Ecossistema , Variação Genética/genética , Glicina/análogos & derivados , Glicina/toxicidade , Herbicidas/toxicidade , Larva/efeitos dos fármacos , Malation/toxicidade , Permetrina/toxicidade , Praguicidas/toxicidade , RNA Ribossômico 16S/genética
17.
Parasitology ; 144(6): 817-822, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28073381

RESUMO

Across host-parasite systems, there is evidence that pesticide exposure increases parasite loads and mortality following infection. However, whether these effects are driven by reductions in host resistance to infection or slower rates of parasite clearance is often unclear. Using controlled laboratory experiments, we examined the ability of larval northern leopard frogs (Lithobates pipiens) and American toads (Anaxyrus americanus) to resist and clear trematode (Echinoparyphium sp.) infections following exposure to the insecticide carbaryl. Northern leopard frogs exposed to 1 mg L-1 of carbaryl had 61% higher parasite loads compared with unexposed individuals, while there was no immediate effect of carbaryl on parasite encystment in American toads. However, when tadpoles were exposed to carbaryl and moved to freshwater for 14 days before the parasite challenge, we recovered 37 and 63% more parasites from carbaryl-exposed northern leopard frogs and American toads, respectively, compared with the control. No effects on clearance were found for either species. Collectively, our results suggest that pesticide exposure can reduce the ability of amphibians to resist parasite infections and that these effects can persist weeks following exposure. It is critical for researchers to incorporate species interactions into toxicity studies to improve our understanding of how contaminants affect ecological communities.


Assuntos
Bufonidae/parasitologia , Carbaril/toxicidade , Echinostomatidae/fisiologia , Inseticidas/toxicidade , Rana pipiens/parasitologia , Infecções por Trematódeos/veterinária , Análise de Variância , Animais , Bufonidae/imunologia , Resistência à Doença/efeitos dos fármacos , Echinostomatidae/efeitos dos fármacos , Indiana , Larva/efeitos dos fármacos , Larva/imunologia , Larva/parasitologia , Tanques , Rana pipiens/imunologia , Caramujos/parasitologia , Infecções por Trematódeos/imunologia
18.
Environ Toxicol ; 32(3): 956-969, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27296064

RESUMO

Carbaryl, a widely used carbamate-based insecticide, is a potent anticholinesterase known to induce delayed neurotoxicity following chronic exposure. However, its potential toxic effects on the cochlea, the sensory organ for hearing that contains cholinergic efferent neurons and acetylcholine receptors on the hair cells (HC) and spiral ganglion neurons has heretofore not been evaluated. To assess ototoxic potential of carbaryl, cochlear organotypic cultures from postnatal day 3 rats were treated with doses of carbaryl ranging from 50 to 500 µM for 48 h up to 96 h. Carbaryl damaged both the sensory HC and spiral ganglion neurons in a dose- and duration-dependent manner. HC and neuronal damage was observed at carbaryl concentrations as low as 50 µM after 96-h treatment and 100 µM after 48-h treatment. Hair cell was greatest in the high frequency basal region of the cochlea and progressively decreased towards the apex consistent with the majority of ototoxic drugs. In contrast, damage to the spiral ganglion neurons was of similar magnitude in the basal and apical regions of the cochlea. Carbaryl damage was characterized by soma shrinkage, nuclear condensation and fragmentation, and blebbing, morphological features of programmed cell death. Carbaryl upregulated the expression of executioner caspase-3 in HC and spiral ganglion neurons indicating that cellular damage occurred primarily by caspase-mediated apoptosis. These results suggest that chronic exposure to carbaryl and other carbamate anticholinesterases may be ototoxic. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 956-969, 2017.


Assuntos
Apoptose/efeitos dos fármacos , Carbaril/toxicidade , Cóclea/efeitos dos fármacos , Animais , Caspase 3/metabolismo , Células Cultivadas , Cóclea/metabolismo , Cóclea/patologia , Células Ciliadas Auditivas/citologia , Células Ciliadas Auditivas/efeitos dos fármacos , Células Ciliadas Auditivas/metabolismo , Microscopia Confocal , Ratos , Ratos Sprague-Dawley , Gânglio Espiral da Cóclea/efeitos dos fármacos , Gânglio Espiral da Cóclea/metabolismo , Gânglio Espiral da Cóclea/patologia
19.
Sci Total Environ ; 575: 146-151, 2017 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-27736697

RESUMO

There is a current tendency to develop and apply environmentally friendly techniques that meet the requirements of green analytical chemistry as an alternative to conventional analytical methods. For toxicity evaluation, these alternatives may be found in bioassays such as Tradescantia. This technique, developed in the 1980s, is highly sensitive to evaluate environmental mutagens, simple and cheap. In this paper, the sensibility of both the Tradescantia micronucleus bioassay (Trad-MCN) and the Tradescantia stamen hair bioassay (Trad-SH) were studied for carbaryl, dimethoate and iprodione, common agricultural and domestic pesticides that are currently used in Chile, which have never been tested with such bioassays. Biomonitor exposures were performed by capillary absorption for each individual pesticide over a wide range of concentrations, from maximum residue limits (trace levels) up to the application dose in agricultural fields. In addition, the organochloride 4,4'-DDE was included but only in the concentration range from 0.01mgL-1 to 1mgL-1, mimicking residue concentrations since it is not a commercial product but, rather, the main breakdown product of the persistent organochloride pesticide 4,4-DDT, whose use was discontinued in Chile in the 1980s. The Trad-MCN bioassay revealed a significant increase in micronucleus frequency at the early tetrads of meiotic pollen mother cells of the biomonitor Tradescantia pallida var. purpurea, induced by 4,4'-DDE (for 1mgL-1), dimethoate (for 40mgL-1, 200mgL-1, 400mg/L-1) and carbaryl (for 889mgL-1). Iprodione did not generate any significant change at the tested concentration. Meanwhile, the Trad-SH bioassay was carried out by analysis of the phenotype variations of the stamen hair cells of the Tradescantia clone KU-20 for the same pesticides and doses. This bioassay was not sufficiently sensitive for toxicity evaluation of most of the pesticides tested, with exception of dimethoate in low doses (2 and 5mg/L-1).


Assuntos
Monitoramento Ambiental , Praguicidas/toxicidade , Tradescantia/efeitos dos fármacos , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/toxicidade , Carbaril/toxicidade , Chile , Diclorodifenil Dicloroetileno , Dimetoato/toxicidade , Hidantoínas/toxicidade , Testes para Micronúcleos , Mutagênicos , Tradescantia/genética
20.
Environ Toxicol Chem ; 36(3): 771-779, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27775179

RESUMO

As the numbers of chemical contaminants in freshwater ecosystems increase, it is important to understand whether contaminants interact in ecologically important ways. The present study investigated the independent and interactive effects of 2 contaminants that frequently co-occur in freshwater environments among higher latitudes, including a commonly applied insecticide (carbaryl) and road salt (NaCl). The hypothesis was that the addition of either contaminant would result in a decline in zooplankton, an algal bloom, and the subsequent decline of both periphyton and periphyton consumers. Another hypothesis was that combining the contaminants would result in synergistic effects on community responses. Outdoor mesocosms were used with communities that included phytoplankton, periphyton, zooplankton, amphipods, clams, snails, and tadpoles. Communities were exposed to 4 environmentally relevant concentrations of salt (27 mg Cl- L-1 , 77 mg Cl- L-1 , 277 mg Cl- L-1 , and 727 mg Cl- L-1 ) fully crossed with 4 carbaryl treatments (ethanol, 0 µg L-1 , 5 µg L-1 , and 50 µg L-1 ) over 57 d. Contaminants induced declines in rotifer and cladoceran zooplankton, but only carbaryl induced an algal bloom. Consumers exhibited both positive and negative responses to contaminants, which were likely the result of both indirect community interactions and direct toxicity. In contrast to the hypothesis, no synergistic effects were found, although copepod densities declined when high concentrations of both chemicals were combined. The results suggest that low concentrations of salt and carbaryl are likely to have mostly independent effects on aquatic communities. Environ Toxicol Chem 2017;36:771-779. © 2016 SETAC.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Carbaril/toxicidade , Inseticidas/toxicidade , Cloreto de Sódio/toxicidade , Poluentes Químicos da Água/toxicidade , Áreas Alagadas , Animais , Relação Dose-Resposta a Droga , Ecologia , Ecossistema , Água Doce/química , Larva/efeitos dos fármacos , Modelos Teóricos , Fitoplâncton/efeitos dos fármacos , Estados Unidos , Zooplâncton/efeitos dos fármacos
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