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1.
Chemosphere ; 240: 124973, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726602

RESUMO

Pesticides are the chemicals of increased concern regarding their adverse environmental effects. In particular, the reports on their joint toxicity effects are scarce in the literature. Therefore, this paper describes the experiments on toxicities of four pesticides: alachlor, chlorfenvinphos, diuron, and isoproturon, toward Vibrio fischeri. In particular, the joint toxicity effects for all possible binary combinations of the pesticides were analyzed. The analysis included the application of concentration addition and independent action models at two toxicity levels: EC10 and EC50. The analysis revealed additive behavior between all pesticide pairs. The only exception was isoproturon and chlorfenvinphos whose combination resulted in synergistic toxic activity. The original form of the logistic function was given preference over the linearized form in describing the response-dose relationships of investigated pesticides.


Assuntos
Misturas Complexas/toxicidade , Praguicidas/toxicidade , Acetamidas/toxicidade , Aliivibrio fischeri/efeitos dos fármacos , Clorfenvinfos/toxicidade , Diurona/toxicidade , Interações de Medicamentos , Compostos de Fenilureia/toxicidade
2.
Sci Total Environ ; 688: 960-969, 2019 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-31726578

RESUMO

Fatty acids (FA) are crucial for the maintenance of membrane fluidity and play a central role in metabolic energy storage. Polyunsaturated fatty acids play an essential ecological role since they are key parameters in the nutritional value of algae. Pesticide impacts on fatty acid profiles have been documented in marine microalgae, but remain understudied in freshwater diatoms. The aims of this study were to: 1) investigate the impact of diuron and S-metolachlor on "classical descriptors" (photosynthesis, growth rate, pigment contents, and on the expression levels of target genes in freshwater diatoms), 2) examine the impact of these pesticides on diatom fatty acid profiles and finally, 3) compare fatty acid profiles and "classical descriptor" responses in order to evaluate their complementarity and ecological role. To address this issue, the model freshwater diatom Gomphonema gracile was exposed during seven days to diuron and S-metolachlor at 10 µg.L-1. G. gracile was mostly composed of the following fatty acids: 20:5n3; 16:1; 16:0; 16:3n4; 14:0 and 20:4n6 and highly unsaturated fatty acids were overall the best represented fatty acid class. S-metolachlor decreased the growth rate and chlorophyll a content of G. gracile and induced the expression of cox1, nad5, d1 and cat genes, while no significant impacts were observed on photosynthesis and carotenoid content. In a more global way, S-metolachlor did not impact the fatty acid profiles of G. gracile. Diuron inhibited photosynthesis, growth rate, chlorophyll a content and induced cat and d1 gene expressions but no significant effect was observed on carotenoid content. Diuron decreased the percentage of highly unsaturated fatty acids but increased the percentage of monounsaturated fatty acids. These results demonstrated that fatty acids responded to diuron conversely to pigment content, suggesting that fatty acids can inform on energy content variation in diatoms subjected to herbicide stress.


Assuntos
Acetamidas/toxicidade , Diatomáceas/fisiologia , Diurona/toxicidade , Herbicidas/toxicidade , Ácidos Graxos , Testes de Toxicidade , Poluentes Químicos da Água/toxicidade
3.
J Water Health ; 17(5): 683-690, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31638020

RESUMO

The presence of disinfection by-products (DBPs) increases the mutagenicity of water and may pose adverse health effects. Gut microbiota exerts a fundamental role on host physiology, and how extrinsic perturbations influence its composition has been increasingly examined. However, the effect of DBPs on gut microbiota is still poorly understood. In the present study, adult zebrafish were exposed to different concentrations of dichloroacetamide (DCAcAm, an emerging nitrogenous DBP) for 30 days. Sequencing of 16S rRNA amplicons revealed a significant change in the richness and diversity of microbiota in the gut of DCAcAm-exposed zebrafish. At the phylum level, the abundance of Proteobacteria decreased and the abundance of Fusobacteria and Firmicutes increased significantly in the gut after exposure to 100 and 500 µg/L DCAcAm. At the genus level, the abundances of several bacteria which are considered pathogens or opportunistic pathogens in fish and closely related to fish metabolism, disease and inflammation (Aeromonas, Stenotrophomonas, Bacteroides and Ralstonia) increased in the DCAcAm-treated groups. Our results reveal that DBPs in drinking water potentially affect gut microbiota composition, which may contribute to the toxicity assessment of DBPs in future and provide new insight into the complex interactions between the DBPs in drinking water and host health.


Assuntos
Acetamidas/toxicidade , Desinfetantes/toxicidade , Microbioma Gastrointestinal , Purificação da Água , Peixe-Zebra/microbiologia , Animais , Desinfecção , Água Potável/química , RNA Ribossômico 16S
4.
Ecotoxicol Environ Saf ; 185: 109702, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31585394

RESUMO

The purpose of our work was to determine the acute and chronic toxicity of three of the EU's most common herbicides - mesotrione, S-metolachlor, terbuthylazine - and their mixtures by Aliivibrio fischeri ecotoxicological assays. While comparing the sensitivity of the acute (30 min) Microtox® standard assay with the chronic (25 h) test adapted to microtiter plate, joint effects (antagonism, additive effect and synergism) to the bioluminescence inhibition (consequently the metabolic damage) in A. fischeri were also determined by Combination Index (CI) method. 30 min of exposure to mesotrione and S-metolachlor resulted in a relatively low acute toxicity (EC50 values were 118 and 265 mg/L), while terbuthylazine did not cause bioluminescence inhibition at all. Results showed that the chronic toxicity of S-metolachlor and terbuthylazine to A. fischeri (EC5010h = 59.2 and 4.9 mg/L and EC5015h = 54.0 and 9.6 mg/L, respectively) is larger by at least one order of magnitude than that after 30 min of contact time. Considering mesotrione no significant difference was experienced in toxicity. Regarding the EC50 values, all of the mixtures had synergistic joint effects in the acute assay. However, in the chronic test all the mixtures showed antagonistic responses with the exception of mesotrione and S-metolachlor (ratio 1:1) combination, which also had additive and synergistic effects after 10 and 15 h of exposure, similarly to the short-term test. This is also the first report of the joint effects of these herbicides. The chronic test is a more sensitive indicator to the active ingredients; both acute and chronic assays supply valuable data of the toxic properties of the pesticides. Moreover, the short- and long-term joint effects of their mixtures supporting a more accurate and reliable risk assessment.


Assuntos
Acetamidas/toxicidade , Aliivibrio fischeri/efeitos dos fármacos , Cicloexanonas/toxicidade , Herbicidas/toxicidade , Triazinas/toxicidade , Poluentes Químicos da Água/toxicidade , Acetamidas/química , Bioensaio , Cicloexanonas/química , Relação Dose-Resposta a Droga , Ecotoxicologia , Herbicidas/química , Testes de Toxicidade Aguda , Testes de Toxicidade Crônica , Triazinas/química , Poluentes Químicos da Água/química
5.
Ecotoxicol Environ Saf ; 184: 109629, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31509783

RESUMO

To investigate the induction of oxidative stress and antioxidant response in the chloroacetanilides-degrading Trichoderma spp. under alachlor and metolachlor exposure, a comparative analysis using popular biomarkers was employed. An increased intracellular level of reactive oxygen species (ROS; especially superoxide anion [O2-]) as well as products of lipid and protein oxidation after 24 h incubation with the herbicides confirmed chloroacetanilide-induced oxidative stress in tested Trichoderma strains. However, the considerable decline in the ROS levels and the carbonyl group content (biomarkers of protein peroxidation) in a time-dependent manner and changes in the antioxidant enzyme activities indicated an active response against chloroacetanilide-induced oxidative stress and the mechanism of tolerance in tested fungi. Moreover, the tested herbicides clearly modified the phospholipids (PLs) content in Trichoderma spp. in the stationary phase of growth, which was manifested through the difference in phosphatidic acid (PA), phosphatidylethanolamine (PE) and phosphatidylcholines (PC) levels. Despite enhanced lipid peroxidation and changes in PLs in most tested fungi, only a slight modification in membrane integrity of Trichoderma spp. under chloroacetanilides exposure was noted. The obtained results suggest that the alterations in the antioxidant system and the PLs profile of Trichoderma spp. might be useful biomarkers of chloroacetanilide-induced oxidative stress.


Assuntos
Herbicidas/metabolismo , Estresse Oxidativo , Fosfolipídeos/metabolismo , Trichoderma/metabolismo , Acetamidas/metabolismo , Acetamidas/toxicidade , Antioxidantes/metabolismo , Biodegradação Ambiental , Herbicidas/toxicidade , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Trichoderma/efeitos dos fármacos
6.
Sci Total Environ ; 692: 1267-1275, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539958

RESUMO

Humans are exposed to disinfection by-products (DBPs) mainly through drinking water ingestion and dermal contact. As an emerging class of nitrogenous DBPs (N-DBPs), haloacetamides (HAcAms) have been found to have significantly higher cytotoxicity than regulated DBPs. In this study, we investigated the cytotoxicity of HAcAms on two exposure pathway-related cell lines: human gastric epithelial GES-1 cells and immortalized keratinocytes HaCaT. Our results showed that the ranking order of cytotoxicity of 13 HAcAms was different between HaCaT and GES-1 cells. In addition, the 50% inhibitive concentration in HaCaT was 1.01-3.29 times that in GES-1. Further comparison among GES-1, HaCaT and CHO cell lines confirmed that different cell lines exhibited different sensitivity to the same compound. Importantly, HAcAms showed 5.83-7.13 × 104 times higher toxicity than the well-clarified DBP chloroform, clearly demonstrating the increased toxicity of HAcAms. Finally, using a novel high-content screening (HCS) analysis, we found that 39.29% of chlorinated HAcAms, 42.86% of brominated HAcAms and 16.07% of iodinated HAcAms significantly affected at least one of the cell-health parameters, such as nuclear size, membrane permeability, mitochondrial membrane potential, or cytochrome c release, in GES-1 or HaCaT cells. Thus, brominated HAcAms appear to have stronger effects under the sublethal exposure dose, possibly causing cytotoxicity via apoptosis. Together, our study provides new insights to the toxicity of HAcAms and a comprehensive toxicology dataset for health risk assessment.


Assuntos
Acetamidas/toxicidade , Desinfetantes/toxicidade , Poluentes Químicos da Água/toxicidade , Linhagem Celular , Desinfecção , Humanos , Testes de Toxicidade
7.
Bull Environ Contam Toxicol ; 103(5): 663-669, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31473775

RESUMO

Climate change is expected to alter hydrological cycles on global and regional scales, impacting groundwater and surface water inputs to stream habitats. In the midwestern United States, the volume and frequency of inputs are expected to become increasingly variable. This region has a high incidence of agriculture, creating enormous potential for transport of pesticides and herbicides into aquatic ecosystems. Metolachlor, an herbicide for corn and soybean crops, has been demonstrated to contaminate surface water and groundwater in the region. This study examines the impact of variable flow conditions on the toxicity of environmentally relevant concentrations of metolachlor in a macroinvertebrate found in midwestern streams, the rusty crayfish (Faxonius rusticus). Changes in crayfish foraging behavior were analyzed using a Mixed Model ANCOVA. Under toxicant exposure, crayfish significantly increased their consumption of macrophytes, but only under the variable flow regime. Thus, the increased variability in toxicant exposure impacted crayfish foraging behavior more than other flow regimes. This significant interaction between flow regime and metolachlor exposure suggests that the greater variability in toxicant inputs to streams may lead to more severe changes in behavior for exposed organisms.


Assuntos
Acetamidas/toxicidade , Astacoidea/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Herbicidas/toxicidade , Ciclo Hidrológico , Poluentes Químicos da Água/toxicidade , Animais , Astacoidea/fisiologia , Ecossistema , Água Subterrânea/química , Meio-Oeste dos Estados Unidos , Rios/química
8.
J Environ Sci Health B ; 54(10): 832-842, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31280652

RESUMO

This study was aimed to evaluate the effect of a mixture of flufenacet + isoxaflutole on counts of microorganisms, ecophysiological diversity index (EP), colony development index (CD) and on the enzymatic activity of soil and maize growth. The experiment was conducted with sandy clay, to which the tested herbicide was administered in doses of: 0.25, 5.0, 10, 20, 40, 80 and 160 mg/kg. Soil without the addition of the mixture served as the control. Results demonstrated that the tested mixture contributed to a decrease in numbers of Azotobacter, organotrophic bacteria, actinobacteria and fungi. The negative effect of the herbicide could also be noticed in the case of the enzymatic activity of soil. Soil contamination contributed to suppressed activities of dehydrogenases, catalase, urease, alkaline phosphatase and arylsulfatase. In turn, the initial increase in the activity of ß-glucosidase was followed by its decline observed with time. The flufenacet + isoxaflutole mixture affected also maize plant growth, reducing maize dry matter yield when used at doses from 5.0 to 160 mg/kg. In summary, it may be concluded that mixture evokes a negative effect on the microbiological and biochemical activity of soil and that their excess in the soil leads to plant decay as at the seeding stage.


Assuntos
Acetamidas/toxicidade , Herbicidas/toxicidade , Isoxazóis/toxicidade , Microbiologia do Solo , Poluentes do Solo/toxicidade , Tiadiazóis/toxicidade , Zea mays/crescimento & desenvolvimento , Actinobacteria/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Enzimas/metabolismo , Fungos/efeitos dos fármacos , Oxirredutases/metabolismo , Solo/química , Urease/metabolismo
9.
Sci Total Environ ; 690: 181-188, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31288109

RESUMO

Agricultural chemicals are normally used as mixtures of several isomers, e.g., enantiomers. In theory, in order to minimize the pesticides dose, it is desirable to use the most target-active isomer. Metolachlor is a typical multichiral herbicide belonging to amide herbicides. An asymmetric carbon atom and a chiral axis yield four stereoisomers. In this study, a novel laboratory method was developed to prepare the S-metolachlor and the four stereoisomers using high performance liquid chromatography. The separated isomers had a purity of >99%, with their absolute configurations assigned by electronic circular dichroism. The enantioseparation by ultra performance convergence chromatography tandem mass spectrometry was also performed for the rapid and sensitive detection of metolachlor stereoisomers. The enantioselective herbicidal activity toward the target weed (Echinochloa crusgalli) was systematically assessed for the first time by measuring the morphology of the weed after treatment with rac-, S-metolachlor and the four stereoisomers, respectively. Among the commercial pesticides, S-metolachlor was more effective in weed inhibition than rac-metolachlor, and to the four stereoisomers, the herbicidal activities were ranked as: SS > SR ≫ RS > RR, and the RR-isomer even had some stimulative effect to the weed growth at lower concentration (1 ppm). Thus, we concluded that in these cases, the chiral carbon feature played a major role in herbicidal activity rather than the chiral axis feature, and the higher bioactivity of the S-isomers was confirmed by more effective uptake and stronger interaction with target enzymes that were involved in the gibberellic acid biosynthesis. Although the SS-isomer shows the highest herbicidal activity, controlling the major chiral feature is still much easier and more economical than controlling two chiral features.


Assuntos
Acetamidas/toxicidade , Agroquímicos/toxicidade , Echinochloa/efeitos dos fármacos , Herbicidas/toxicidade , Acetamidas/química , Agroquímicos/química , Relação Dose-Resposta a Droga , Herbicidas/química , Estereoisomerismo
10.
Environ Toxicol ; 34(7): 781-787, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30884105

RESUMO

To evaluate the impact of DCAcAm on zebrafish gill, we measure the responses of antioxidant enzyme (superoxide dismutase, SOD), lipid peroxidation (malondialdehyde, MDA), ATPase (Na+ /K+ -ATPase and Ca2+ /Mg2+ -ATP) and histopathological changes of gill in adult zebrafish, after exposed to different concentrations of DCAcAm (0, 1, 10, 100, and 1000 µg L-1 ) for 30 days. Results indicated that DCAcAm first increased and then decreased SOD activity, and DCAcAm also lowered the activities of Na+ /K+ -ATPase and Ca2+ /Mg2+ -ATPase. These results indicated that high affinity of DCAcAm probably be a main factor, which can damage the structures of enzymes, thereby inhibiting the SOD and ATPase activities. Besides, histopathological investigation results also manifested that chronic exposure to DCAcAm can damage the gill tissues, disrupting the normal function of gills. We conclude that chronic exposure to DCAcAm was harmful to organisms, not only influence gill function, but also further cause damage on the gill tissues.


Assuntos
Acetamidas/toxicidade , Brânquias/efeitos dos fármacos , Brânquias/patologia , Poluentes Químicos da Água/toxicidade , Peixe-Zebra , Animais , Antioxidantes/metabolismo , Exposição Ambiental , Brânquias/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Superóxido Dismutase/metabolismo , Fatores de Tempo , Peixe-Zebra/anatomia & histologia , Peixe-Zebra/metabolismo
11.
Pestic Biochem Physiol ; 153: 87-94, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30744900

RESUMO

The effects of s-metolachlor chronic exposure at concentrations of 1.1 µg/L (maximal real environmental concentration in the Czech Republic), 11 µg/L (environmental relevant concentration) and 110 µg/L on early life stages of marbled crayfish (Procambarus virginalis) was evaluated under laboratory conditions. All s-metolachlor exposures resulted in higher mortality, delay ontogenetic development with accompanied slower growth and excited behaviour (increase of total distance moved and walking speed). Significantly lower superoxide dismutase, catalase, glutathione S-transferase activity and reduced glutathione level was observed at two higher tested concentrations (11 and 110 µg/L) of s-metolachlor compared with the control. S-metolachlor in concentrations 110 µg/L showed alteration of the tubular system of hepatopancreas including focal disintegration of tubular epithelium and notable reduction in epithelial cells number, especially B-cells. In conclusion, potential risk associated with using of s-metolachlor in agriculture, due to effects on non-target aquatic organisms as documented on early life stages of marbled crayfish in this study, should be taken into account.


Assuntos
Acetamidas/toxicidade , Astacoidea/efeitos dos fármacos , Herbicidas/toxicidade , Animais , Astacoidea/fisiologia , Comportamento Animal/efeitos dos fármacos , Feminino , Hepatopâncreas/efeitos dos fármacos , Hepatopâncreas/patologia
12.
Bull Environ Contam Toxicol ; 102(3): 439-445, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30734056

RESUMO

The unfounded use of chiral pesticides has caused widespread concern. In this study, the enantioselective effects of S- and racemic (Rac)-metolachlor on the oxidative stress of wheat seedlings was determined based on physiological and gene transcription differences. Growth inhibition increased with increasing concentrations of tested metolachlor, and S-metolachlor had a stronger inhibitory effect than did Rac-metolachlor. Root growth was also significantly inhibited, but no enantioselective effects from the tested concentrations of the metolachlor enantiomers were observed. At a concentration of 5 mg L-1, the maximal fresh weight inhibition reached 63.7% and 53.8% for S-metolachlor and Rac-metolachlor, respectively. In response to the S-metolachlor treatment, the maximum level of superoxide anions and malondialdehyde (MDA) increased to 1.73 and 2.55 times that in response to the control treatment, both of which were greater than those in response to the Rac-metolachlor treatment. The activity of superoxide dismutase (SOD) also increased in response to the S-metolachlor treatment, but the activity of peroxidase (POD) decreased. Real-time polymerase chain reaction (PCR) revealed that, compared with the Rac-metolachlor treatment, the S-metolachlor treatment attenuated the expression of several antioxidant genes. Together, these results demonstrate that S-metolachlor has a greater effect than does Rac-metolachlor on wheat seedlings.


Assuntos
Acetamidas/toxicidade , Herbicidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Poluentes do Solo/toxicidade , Triticum/efeitos dos fármacos , Acetamidas/química , Antioxidantes/metabolismo , Herbicidas/química , Plântula/metabolismo , Poluentes do Solo/química , Estereoisomerismo , Triticum/metabolismo
13.
J Agric Food Chem ; 67(6): 1631-1637, 2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30673265

RESUMO

The enantioselective effects of chiral herbicides on aquatic organisms have received increasing attention. As one kind of freshwater algae responsible for most algal blooms, Microcystis aeruginosa can produce hepatotoxic microcystin and cause serious health concerns for drinking water. Thus, the effects of chiral herbicides on M. aeruginosa are of vital significance but poorly understood, especially as the structures of chiral herbicides become more complex. In this study, the enantioselective effects of four metolachlor enantiomers based on carbon center and axis chirality on M. aeruginosa were investigated for the first time at an enantiomeric level. The results of the investigation into algal growth inhibition, chlorophyll a content, and cell integrity indicated that ( S)-metolachlor [( S)-Met] was significantly more toxic than any other isomer. The toxicity ranking of different enantiomers at the highest concentration (15 mg/L) against M. aeruginosa was ( S)-Met > (α R,1' S)-Met > (α S,1' S)-Met > (α S,1' R)-Met > (α R,1' R)-Met, with (α S,1' S)-Met and (α R,1' S)-Met displaying a synergistic effect. Additionally, the Fe distribution in M. aeruginosa presented distinct enantioselectivity, which may contribute to the enantioselective toxicity of metolachlor. Furthermore, metolachlor upregulated the expression of genes mcyD and mcyH in an enantioselective manner, indicating that this herbicide can potentially promote the synthesis and efflux of microcystin, thus aggravating agricultural water contamination to different extents. Overall, this study will help to understand the ecotoxicity of metolachlor at a deeper level and provide theoretical insights into the enantioselective behaviors of metolachlor.


Assuntos
Acetamidas/toxicidade , Herbicidas/química , Herbicidas/toxicidade , Microcystis/efeitos dos fármacos , Acetamidas/química , Clorofila A/metabolismo , Microcistinas/metabolismo , Microcystis/crescimento & desenvolvimento , Microcystis/metabolismo , Estereoisomerismo
14.
Bioorg Med Chem ; 27(5): 777-784, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30692023

RESUMO

A simple and one-pot approach for the synthesis of highly functionalized novel (E)-2-benzylideno-(Z)-carbazolylideno cyanoacetamide derivatives from different 2-(2',3',4',9'-tetrahydro-carbazol-1'-ylidene)-propanedinitriles and aryl/heteroaryl carbaldehydes via vinylogous aldol reaction. The structures of the molecules were designated by FT-IR, 1H NMR, 13C NMR studies, elemental and X-ray crystallographic analysis. The synthesized pure products have been screened for in vitro antibiofilm inhibitory activity towards antibiotic-resistant pathogenic organisms. All the synthesized compounds showed biofilm inhibition. Promisingly, the moieties 3a, 3d and 3h showed higher antibiofilm activity at biofilm inhibitory concentration (BIC) (200 µg/mL) against bacterial pathogens. Among the three moieties, 3a showed high prospective against E. coli biofilm with minimal and maximal BIC percentage of 32% (10 µg/mL) and 89% (100 µg/mL) and chosen lowest BIC for further evaluation. Also, the 3a generate ROS two fold at 1 h treatment in E. coli biofilm. The 3a exhibited no toxic effect on cell viability upto 75 µg/mL in HEK293 cell lines. The results of the present study reveal that among (E)-2-benzylideno-(Z)-carbazolylideno cyanoacetamides, (E)-2-benzylideno-6-methyl-2,3,4,9-tetrahydro-1H-carbazol-(Z)-α-carbamino-α-cyano-1-ylidene (3a) could be exploited as an excellent antibiofilm agent against carbapenem-resistant E. coli bacteria strains.


Assuntos
Acetamidas/farmacologia , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Carbazóis/farmacologia , Acetamidas/síntese química , Acetamidas/toxicidade , Antibacterianos/síntese química , Antibacterianos/toxicidade , Bacillus megaterium/efeitos dos fármacos , Bacillus subtilis/efeitos dos fármacos , Carbazóis/síntese química , Carbazóis/toxicidade , Bactérias Gram-Negativas/efeitos dos fármacos , Células HEK293 , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-Atividade
15.
Environ Sci Pollut Res Int ; 26(4): 3465-3472, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30515692

RESUMO

A simple and fast method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for cymoxanil residue analysis in grape. Sample preparation based on solid-liquid extraction was optimized without using adsorbent for purification. Recoveries were 79.8-109.5% with relative standard deviations (RSDs) of 2.5-9.4% at fortified levels from 0.001 to 0.50 mg/kg. The limit of detection (LOD) was 0.3 µg/kg. Field trials were conducted to explore the dissipation and terminal residue behavior of cymoxanil in grape. Results showed that the half-lives of cymoxanil were from 0.5 to 0.7 days. Terminal residues were from below the limit of quantification (LOQ) to 0.363 mg/kg. Dietary exposure risk assessment revealed that the risk quotients (RQs) were much less than 1. It was concluded that cymoxanil in grape raised negligible concerns to human health under field conditions. Sixty grape samples from Guangzhou market were found to be free of cymoxanil. The proposed study would provide reference for appropriate use of cymoxanil in grape planting in China.


Assuntos
Acetamidas/análise , Resíduos de Praguicidas/análise , Vitis/química , Acetamidas/toxicidade , China , Cromatografia Líquida/métodos , Exposição Dietética , Humanos , Limite de Detecção , Resíduos de Praguicidas/toxicidade , Medição de Risco , Inquéritos e Questionários , Espectrometria de Massas em Tandem/métodos
16.
Sci Total Environ ; 643: 1456-1463, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30189562

RESUMO

The metolachlor OA is a metabolite of herbicide metolachlor and s-metolachlor. The objective of the present study was to assess the effect metolachlor OA on early life stages of marbled crayfish (Procambarus virginalis). The early life stages of marbled crayfish were exposed for 45 days to three concentrations of metolachlor OA: 4.2 µg/L (environmentally relevant concentration, E1), 42 µg/L (E2) and 420 µg/L (E3) under laboratory conditions. The effects were assessed on the basis of mortality, growth, ontogenetic development, behaviour, oxidative stress, antioxidant biomarkers and histopathology. Metolachlor OA caused significantly lower growth, superoxide dismutase, catalase and glutathione s-transferase activity in all tested concentrations. Metolachlor OA in higher concentrations (42 and 420 µg/L) resulted in significantly delayed ontogenetic development, lower reduced glutathione level and lipid peroxidation. Metolachlor OA has not significant effect on behaviour (activity, total distance moved and walking speed). Histological examination revealed alteration of hepatopancreas and gills in crayfish exposed to two higher tested concentrations. Hepatopancreas reflected histomorphological structural changes of individual cell types. Changes of gills included focal hemocytic infiltration together with enlargement of intralamellar space packed with granular substance. In conclusion, chronic metolachlor OA exposure affected growth, ontogenetic development, and the antioxidant system and caused pathological changes in hepatopancreas and gills of early life stages of marbled crayfish.


Assuntos
Acetamidas/toxicidade , Astacoidea/fisiologia , Herbicidas/toxicidade , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Catalase/metabolismo , Brânquias , Estresse Oxidativo , Superóxido Dismutase/metabolismo
17.
Ann Work Expo Health ; 62(9): 1147-1158, 2018 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-30239593

RESUMO

Vegetable farmers applying the herbicide alachlor may be highly exposed through dermal contact when spraying. Dermal patches were attached to 10 locations on the farmers' skin when they mixed and applied alachlor in vegetable farming areas in Thailand. Measurements were made on farmers using either a backpack sprayer with a 2 stroke gasoline motor and fan or a battery operated pump. Forty-seven vegetable farmers in Bungphra subdistrict of Thailand participated in this study. Both motorized and battery pump backpack sprayers wearing long-sleeve shirts had significantly lower alachlor concentrations on the dermal patches under their long-sleeve shirts compared to those who wore only short-sleeve shirts, regardless of the sprayer type. Moreover, sprayers wearing long pants had significantly lower alachlor concentrations on dermal patches placed under the pants on the lower legs than those wearing short pants, regardless of the sprayer type. The highest estimated alachlor exposures were found on the upper legs (median = 9.29 µg/h) for those using a 2 stroke engine/fan backpack sprayer and on the lower legs (2.87 µg/h) for those using the battery operated pump backpack sprayer. The estimated total body alachlor exposures of applicators using the 2 stroke engine/fan backpack sprayer (219.48 µg/h) were significantly higher than those using the battery operated pump backpack sprayer (15.50 µg/h). Using long-sleeve shirts as personal protection reduced alachlor exposures for the arms 97-99% and wearing long pants reduced alachlor exposure to the legs for 81-99%. Thus, training about the protection provided by clothing choices would be one step in improving the health and safety of Thai farmers.


Assuntos
Acetamidas/análise , Agricultura , Herbicidas/análise , Exposição Ocupacional/análise , Acetamidas/toxicidade , Adulto , Doenças dos Trabalhadores Agrícolas/prevenção & controle , Feminino , Herbicidas/toxicidade , Humanos , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional/prevenção & controle , Roupa de Proteção/normas , Análise de Regressão , Testes Cutâneos/métodos , Tailândia , Verduras
18.
Toxicol Lett ; 299: 104-117, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30244016

RESUMO

DON, NX-3 and butenolide (BUT) are secondary metabolites formed by Fusarium graminearum. Evidence for formation of DON-glutathione adducts exists in plants, and also in human liver (HepG2) cells mass spectrometric evidence for GSH-adduct formation was reported. NX-3 is a DON derivative lacking structural features for Thiol-Michael addition, while BUT has the structural requirements (conjugated double bond and keto group). In the present study, we addressed whether these structural differences affect levels of intracellular reactive oxygen species in HepG2 cells, and if intracellular GSH levels influence toxic effects induced by DON, NX-3 and BUT. Pre-treatment with an inhibitor of GSH bio-synthesis, L-buthionine-[S,R]-sulfoximine, aggravated substantially BUT-induced cytotoxicity (≥50 µM, 24 h), but only marginally affected the cytotoxicity of DON and NX-3 indicating that GSH-mediated detoxification is of minor importance in HepG2 cells. We further investigated whether BUT, a compound inducing alone low oral toxicity, might affect the toxicity of DON. Under different experimental designs with respect to pre- and/or co-incubations, BUT was found to contribute to the combinatorial cytotoxicity, exceeding the toxic effect of DON alone. The observed combinatorial effects underline the potential contribution of secondary metabolites like BUT, considered to be alone of low toxicological relevance, to the toxicity of DON or structurally related trichothecenes, arguing for further studies on the toxicological relevance of naturally occurring mixtures.


Assuntos
Acetamidas/toxicidade , Furanos/toxicidade , Fusarium , Glutationa/metabolismo , Tricotecenos/toxicidade , Elementos de Resposta Antioxidante/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Hep G2 , Humanos , Fator de Transcrição NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
19.
Bioorg Chem ; 81: 253-263, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30153590

RESUMO

Current study is based on the sequential conversion of indolyl butanoic acid (1) into ethyl indolyl butanoate (2), indolyl butanohydrazide (3), and 1,3,4-oxadiazole-2-thiol analogs (4) by adopting chemical transformations. In a parallel series of reactions, 2-bromo-N-phenyl/arylacetamides (7a-l) were synthesized by reacting different amines derivatives (5a-l) with 2-bromoacetyl bromide (6) to serve as electrophile. Then, the synthesized electrophiles (7a-l) were treated with nucleophilic 1,3,4-oxadiazole-2-thiol analog (4) to afford a range of N-substituted derivatives (8a-l). The structural confirmation of all the synthetic compounds was carried out by IR, 1H-, 13C NMR, EI-MS, and CHN analysis data. All synthesized molecules (8a-l) were tested for their antidiabetic potential via inhibition of the α-glucosidase enzyme followed by their in silico study. Their cytotoxicity profile was also ascertained via hemolytic activity and all of them possessed very low cytotoxicity. Compounds 8h and 8l were found most active having IC50 values 9.46 ±â€¯0.03 µM and 9.37 ±â€¯0.03 µM, respectively. However, all other molecules also exhibited good to moderate inhibition potential with IC50 values between 12.68 ±â€¯0.04-37.82 ±â€¯0.07, compared to standard acarbose (IC50 = 37.38 ±â€¯0.12 µM), hence can be used as lead molecules for further research in order to get better antidiabetic agents.


Assuntos
Acetamidas/química , Inibidores de Glicosídeo Hidrolases/química , Hipoglicemiantes/química , Indóis/química , Oxidiazóis/química , Acetamidas/síntese química , Acetamidas/toxicidade , Animais , Domínio Catalítico , Bovinos , Inibidores de Glicosídeo Hidrolases/síntese química , Inibidores de Glicosídeo Hidrolases/toxicidade , Hemólise/efeitos dos fármacos , Hipoglicemiantes/síntese química , Hipoglicemiantes/toxicidade , Indóis/síntese química , Indóis/toxicidade , Simulação de Acoplamento Molecular , Estrutura Molecular , Oxidiazóis/síntese química , Oxidiazóis/toxicidade , Relação Estrutura-Atividade , alfa-Glucosidases/química
20.
Sci Rep ; 8(1): 12380, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-30120374

RESUMO

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator of cellular defense against oxidative stress and correlated with classical toxicological endpoints. In vitro methods using fish cell lines for the assessment of aquatic toxicity are needed for mechanistic studies and as an alternative to in vivo. We describe an in vitro assay to study oxidative stress using zebrafish cell lines. Transfection efficiency of twelve commercially available transfection reagents were tested in the zebrafish cell lines ZFL, ZF4, and Pac2. The most efficient reagent for each cell line was selected for further experiments. Cells were transiently transfected with an Nrf2-responsive luciferase plasmid. The assay was tested using the oxidative stress inducing chemicals tertbutylhydroquinone, hydrogen peroxide, and sulforaphane. Of the transfected cell lines, ZF4 and ZFL showed higher sensitivity. The latter were used to study potential oxidative stress induced by pesticides (diazinon, deltamethrin, atrazine, metazachlor, terbutylazine, diuron). Besides known inducers, Nrf2 activity was also significantly induced by diazinon, deltametrin, diuron, and metazachlor. Activation of Nrf2 by metazachlor is a novel finding. The described assay could be a valuable tool for research in toxicology to study the stress response of both pure chemicals and environmental water samples.


Assuntos
Bioensaio/métodos , Estresse Oxidativo/efeitos dos fármacos , Peixe-Zebra/metabolismo , Acetamidas/toxicidade , Animais , Atrazina/toxicidade , Linhagem Celular , Diazinon/toxicidade , Diurona/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Peróxido de Hidrogênio/toxicidade , Isotiocianatos/toxicidade , Fator 2 Relacionado a NF-E2/metabolismo , Nitrilos/toxicidade , Praguicidas/toxicidade , Piretrinas/toxicidade , Triazinas/toxicidade
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