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1.
Huan Jing Ke Xue ; 42(5): 2550-2557, 2021 May 08.
Artigo em Chinês | MEDLINE | ID: mdl-33884826

RESUMO

The spread of antibiotic resistance has become a serious threat to global public health. Recently, several studies have found that non-antibiotic chemicals can promote the generation and spread of bacterial antibiotic resistance. However, the effects of herbicides on the antibiotic resistance of bacteria remain unclear. In this study, Escherichia coli DH5α was used as the model strain to explore the effects of three commonly used herbicides (glyphosate, glufosinate, and dicamba) on the antibiotic resistance under soil environmental concentrations. The results showed that herbicide exposure affected the sensitivity of E. coli DH5α to antibiotics and significantly improved the resistance of E. coli DH5α to gentamicin (glyphosate > dicamba > glufosinate). After 30 d of herbicide exposure, the E. coli mutant strains enhanced the resistance to tetracycline, chloramphenicol, and aminoglycoside antibiotics, and the minimum inhibitory concentration of streptomycin was increased by 19.8 times. The whole-genome sequencing results illustrated that herbicides induced several previously well-characterized mutations associated with membrane proteins (ompF and papC), fimbriae proteins (yraH), and ribosomes (rpsL) related to antibiotic resistance. Together, the results showed that herbicides can enhance the antibiotic resistance of bacteria via inducing genetic mutations, thereby promoting the potential risk of the spread of antibiotic resistance genes in the environment.


Assuntos
Herbicidas , Antibacterianos/toxicidade , Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Herbicidas/toxicidade , Testes de Sensibilidade Microbiana
2.
J Environ Manage ; 288: 112450, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33823448

RESUMO

The fragility and high cost of enzymes represent critical challenges limiting their practical application in the removal of pesticides. Herein, an aryloxyphenoxypropionate herbicide-hydrolyzing enzyme, QpeH, was purified via one-step affinity chromatography and embedded into two types of zeolitic imidazolate frameworks (ZIFs) through biomimetic mineralization. The catalytic activity towards the herbicide quizalofop-P-ethyl, the loading capacity and efficiency of the resulting two composites, QpeH@ZIF-10 with cruciate flower-like morphology and QpeH@ZIF-8 with rhombic dodecahedral morphology, were compared. Both composites had excellent stability and reusability after 10 reuse cycles, with QpeH@ZIF-10 having a better performance. More importantly, when applied for the removal of quizalofop-P-ethyl pollution in the watermelon field, QpeH@ZIF-10 (88%) showed a remarkably improved degradation efficiency compared to QpeH@ZIF-8 (84%) despite the latter having a greater loading capacity. Finally, the use of QpeH@ZIF composites was shown to recover the bacterial community in soil. This work provides a new insight into the low-cost synthesis of nanobiocatalysts combining simple purified enzymes and metal-organic frameworks (MOFs) for the remediation of pesticide-contaminated soils.


Assuntos
Herbicidas , Estruturas Metalorgânicas , Zeolitas , Esterases , Solo
3.
J Environ Manage ; 288: 112444, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33823450

RESUMO

Effective treatment options are needed for the management of aquatic invasive species. An herbicide treatment was used to control an invasive aquatic plant, yellow floating heart (Nymphoides peltata) in a 3350-acre drinking water reservoir. The purpose of this research was to document the success of the treatment in an individual cove of the reservoir using in-situ sampling and reservoir-wide using remotely sensed Sentinel-2 satellite imagery. We also determined if the dying vegetation negatively impacted biological oxygen demand and dissolved oxygen concentrations in the cove. The aquatic herbicide ProcellaCOR™ (active ingredient = florpyrauxifen-benzyl) was used to treat a 55-acre infestation of YFH at a rate of 3 Prescription Dose Units (PDU)/ac-ft by a certified applicator in July 2019. Total surface coverage of yellow floating heart in the reservoir was reduced by more than 90% within 15 days after the treatment, and to less than 3.0 acres within 50 days after the treatment. No blooming flowers were observed after treatment and the surface coverage was close to 0% within 17 days after treatment in the cove. The effect of the herbicide treatment also appeared to carry over into the following growing season as the total surface coverage of yellow floating heart in the reservoir was less than 8 acres one year after the treatment in July 2020. The herbicide treatment resulted in short term increases in biological oxygen demand and decreases in dissolved oxygen at some sites in the cove within 3-10 days after the treatment. Dissolved oxygen then increased and concentrations were greater 42 days after treatment than they were before the treatment. Our results show that ProcellaCOR™ has the potential to control yellow floating heart infestations with relatively short-term negative impacts on dissolved oxygen concentrations. We also show that Sentinel-2 satellite imagery can be used to monitor the success of herbicide applications over large spatial and temporal scales that would not be possible from ground based monitoring alone.


Assuntos
Água Potável , Herbicidas , Análise da Demanda Biológica de Oxigênio , Monitoramento Ambiental , Qualidade da Água
4.
Int J Mol Sci ; 22(6)2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33803994

RESUMO

We have determined the effect of glyphosate and aminomethylphosphonic acid (AMPA) on expression of genes involved in chromatin architecture in human peripheral blood mononuclear cells (PBMCs). The cells were incubated with glyphosate and AMPA in the concentrations ranging from 0.5 to 100 µM and from 0.5, to 250 µM, respectively. The expression profile of the following genes by quantitative Real-Time PCR was evaluated: Genes involved in the DNA methylation (DNMT1, DNMT3A) and DNA demethylation process (TET3) and those involved in chromatin remodeling: genes involved in the modification of histone methylation (EHMT1, EHMT2) and genes involved in the modification of histone deacetylation (HDAC3, HDAC5). Gene profiling showed that glyphosate changed the expression of DNMT1, DMNT3A, and HDAC3, while AMPA changed the expression of DNMT1 and HDAC3. The results also revealed that glyphosate at lower concentrations than AMPA upregulated the expression of the tested genes. Both compounds studied altered expression of genes, which are characteristic for the regulation of transcriptionally inactive chromatin. However, the unknown activity of many other proteins involved in chromatin structure regulation prevents to carry out an unambiguous evaluation of the effect of tested xenobiotics on the studied process. Undoubtedly, we have observed that glyphosate and AMPA affect epigenetic processes that regulate chromatin architecture.


Assuntos
Cromatina/efeitos dos fármacos , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferases/genética , Dioxigenases/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Cromatina/genética , Metilação de DNA/efeitos dos fármacos , Epigênese Genética/genética , Glicina/análogos & derivados , Glicina/farmacologia , Herbicidas , Antígenos de Histocompatibilidade/genética , Histona Desacetilases/genética , Histona-Lisina N-Metiltransferase/genética , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia
5.
Environ Sci Technol ; 55(9): 6485-6494, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33851826

RESUMO

Synthetic aromatic arsenicals such as roxarsone (Rox(V)) and nitarsone (Nit(V)) have been used as animal growth enhancers and herbicides. Microbes contribute to redox cycling between the relatively less toxic pentavalent and highly toxic trivalent arsenicals. In this study, we report the identification of nemRA operon from Enterobacter sp. Z1 and show that it is involved in trivalent organoarsenical oxidation. Expression of nemA is induced by chromate (Cr(VI)), Rox(III), and Nit(III). Heterologous expression of NemA in Escherichia coli confers resistance to Cr(VI), methylarsenite (MAs(III)), Rox(III), and Nit(III). Purified NemA catalyzes simultaneous Cr(VI) reduction and MAs(III)/Rox(III)/Nit(III) oxidation, and oxidation was enhanced in the presence of Cr(VI). The results of electrophoretic mobility shift assays and fluorescence assays demonstrate that the transcriptional repressor, NemR, binds to either Rox(III) or Nit(III). NemR has three conserved cysteine residues, Cys21, Cys106, and Cys116. Mutation of any of the three resulted in loss of response to Rox(III)/Nit(III), indicating that they form an Rox(III)/Nit(III) binding site. These results show that NemA is a novel trivalent organoarsenical oxidase that is regulated by the trivalent organoarsenical-selective repressor NemR. This discovery expands our knowledge of the molecular mechanisms of organoarsenical oxidation and provides a basis for studying the redox coupling of environmental toxic compounds.


Assuntos
Arsenicais , Herbicidas , Roxarsona , Animais , Escherichia coli/genética , Oxirredução , Oxirredutases
6.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 33(3): 377-380, 2021 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-33834986

RESUMO

Paraquat is a quaternary ammonium herbicide, which can be distributed in lung, liver, kidney, heart, brain and other organs through blood circulation, leading to multiple organ failure, especially lung injury. Due to the lack of effective treatment methods and specific antidotes, the prognosis of most patients with paraquat poisoning is very poor. The treatment of paraquat poisoning was a big problem for emergency doctors. Previous studies have found that pulmonary fibrosis caused by paraquat poisoning is closely related to a variety of pathological processes, such as oxidative stress, inflammatory reaction, mitochondrial damage, imbalance of extracellular matrixproduction (ECM) and degradation, which involve the activation or inhibition of various signaling pathways. In recent years, many researchers focused on clarifying the mechanism of paraquat induced pulmonary fibrosis, and some signaling pathways related to paraquat poisoning leading to pulmonary fibrosis have been found. A large number of studies have found that adenosine monophosphate activated protein kinase (AMPK) related signaling pathway, transforming growth factor-ß/Smad (TGF-ß/Smad) signaling pathway, mitogen-activated protein kinase (MAPK) related signaling pathway, Ras homolog gene/Rho associated kinases (Ras/ROCK) and Wnt/ß-catenin signal pathways are closely related to paraquat induced pulmonary fibrosis. In this paper, we reviewed signaling pathways related to paraquat induced pulmonary fibrosis, in order to provide more ideas for the clinical treatment of paraquat induced pulmonary fibrosis.


Assuntos
Herbicidas , Fibrose Pulmonar , Humanos , Pulmão , Paraquat , Fibrose Pulmonar/induzido quimicamente , Via de Sinalização Wnt
7.
Pestic Biochem Physiol ; 174: 104811, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33838713

RESUMO

Isoxazole, nicotinic acid and benzoic acid are important components in many natural products and useful synthons to build macrostructures having valuable biological activities. In continuation of our effort to discover 4-hydroxyphenylpyruvate dioxygenase (HPPD, EC 1.13.11.27) inhibitors and search for active fragments from natural products, a series of substituted aryl-formyl piperidinone derivatives with natural product fragments was rationally designed, synthesized and tested for their herbicidal activity. Compound I-9 was considered the most effective candidate with an IC50 value of 0.260 µM. The molecular docking results showed that the triketone group of compound I-9 forms a bidentate complex with a metal ion, and the benzene ring interacted with Phe424 and Phe381 via π-π stacking, which was similar to the mechanisms of mesotrione. The present work indicates that compound I-9 may serve as a potential lead compound for further development of green HPPD inhibitors.


Assuntos
Herbicidas , Inibidores Enzimáticos/farmacologia , Herbicidas/farmacologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade
8.
Pestic Biochem Physiol ; 174: 104827, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33838720

RESUMO

Despite the increase in pressure for reducing the use of chemical pesticides in agriculture, herbicides remain one of the efficient tools for augmenting food production. Various herbicide-resistant weeds against most herbicidal modes of action (MoA) are emerging worldwide, and therefore, the necessity of developing herbicides with novel MoA is increasing. Toward this, rigid methods of determining MOA that can be applied for various weeds species are required. Despite the existence of weed species with resistance to acetolactate synthase (ALS) inhibitors, inhibition of ALS remains one of the most widely used herbicidal MoAs containing more than 50 commercial active ingredients. Here, we aimed to identify marker metabolites that are indicative of ALS inhibition. We performed non-targeted and targeted metabolomics using ALS inhibitor-treated Schoenoplectus juncoides. We identified internal metabolite markers for ALS inhibition, with excellent selectivity for ALS inhibitors and herbicides with different MOAs in various weed species. These markers will enable us to evaluate ALS inhibitory activity of chemicals in vivo in a wide variety of weed species.


Assuntos
Acetolactato Sintase , Herbicidas , Resistência a Herbicidas , Herbicidas/farmacologia , Metabolômica , Plantas Daninhas
9.
Artigo em Inglês | MEDLINE | ID: mdl-33801256

RESUMO

The study of the interaction of persistent organic pollutants with biosubstrates helps to unravel the pathways for toxicity, however, few mechanistic data are present in the literature for these systems. We analyzed the binding of paraquat (PQ) and diquat (DQ) herbicides to natural calf thymus DNA and a DNA G-quadruplex by spectrophotometric titrations, ethidium bromide exchange tests, viscometry, and melting experiments. The interaction with bovine serum albumin (BSA) protein was studied spectrofluorimetrically at different temperatures. The retention of the targets on positive, negative, and neutral micellar aggregates and liposomes was analyzed by ultrafiltration experiments. Despite some favorable features, PQ and DQ only externally bind natural DNA and do not interact with DNA oligonucleotides. Both herbicides bind bovine serum albumin (BSA). PQ binds BSA mainly according to an electrostatics-driven process. However, ultrafiltration data also show that some hydrophobic contribution participates in the features of these systems. The practical problems related to unfavorable spectroscopic signals and inner filter effects are also discussed. Overall, both herbicides show a low affinity for nucleic acids and weak penetration into liposomes; in addition, the equilibrium constants values found for BSA system suggest optimal conditions for transport in the body.


Assuntos
Diquat , Herbicidas , Animais , Bovinos , Herbicidas/análise , Paraquat , Ligação Proteica , Soroalbumina Bovina , Análise Espectral
10.
Artigo em Inglês | MEDLINE | ID: mdl-33809586

RESUMO

The herbicides glyphosate, paraquat, and 2,4-D play a significant role in Thailand. This paper is among the first study to describe the intensity of herbicide application and illustrate how the herbicides are extensively distributed over a large area through both agricultural and nonagricultural practices. Using a quick, economical, and simplified method of Material Flow Analysis together with spatial analysis, better data for the analysis of possible environmental herbicide contamination, human exposure, and related health risks for the general public and applicators can be developed. The findings from this study showed that in the study province, about 2.2 million kg of the active ingredients from the three targeted herbicides is applied annually. Pathway flow modeling with spatial analysis identified several local hotspots of concern based on the type of herbicide and crop/activity where it was used. Cassava planting was found to have the highest herbicide application activity, whereas rice cultivation was the major contributor of total herbicide mass, due to the wide area of cultivation in the province. The herbicide most likely to be applied at rates higher than recommended was 2,4-D, particularly on cassava and sugarcane farms.


Assuntos
Herbicidas , Agricultura , Fazendas , Humanos , Paraquat , Tailândia
11.
Ecotoxicology ; 30(4): 733-750, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33821358

RESUMO

Atrazine was banned by the European Union in 2004, but is still used in many countries. Agricultural research employing nanotechnology has been developed in order to reduce the impacts to the environment and nontarget organisms. Nanoatrazine was developed as a carrier system and have been considered efficient in weed control. However, its toxicity must be verified with nontarget organisms. In this context, the aim of the present study was to investigate ecotoxicological effects of solid lipid nanoparticles (empty and loaded with atrazine) and atrazine on Chironomus sancticaroli larvae, evaluating the endpoints: mortality, mentum deformity, development rate and biochemical biomarkers. The contaminant concentrations used were 2, 470, 950, and 1900 µg L-1 in acute (96 h) and 2 µg L-1 in subchronic (10 days) bioassays. An environmentally relevant concentration of atrazine (2 µg L-1) presented toxic and lethal effects towards the larvae. The nanoparticles loaded with atrazine showed toxic effects similar to free atrazine, causing mortality and biochemical alterations on the larvae. The nanoparticle without atrazine caused biochemical alterations and mortality, indicating a possible toxic effect of the formulation on the larvae. In the acute bioassay, most concentrations of nanoparticles loaded with atrazine were not dose dependent for the endpoint mortality. Only the atrazine concentration of 470 µg L-1 was statistically significant to endpoint mentum deformity. The atrazine and nanoparticles (with and without atrazine) did not affect larval development. The results indicate that Chironomus sancticaroli was sensitive to monitor nanoatrazine, presenting potential to be used in studies of toxicity of nanopesticides.


Assuntos
Atrazina , Chironomidae , Herbicidas , Poluentes Químicos da Água , Animais , Atrazina/toxicidade , Ecotoxicologia , Larva , Poluentes Químicos da Água/toxicidade , Controle de Plantas Daninhas
12.
Science ; 372(6537): 81-84, 2021 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-33795455

RESUMO

Pesticide impacts are usually discussed in the context of applied amounts while disregarding the large but environmentally relevant variations in substance-specific toxicity. Here, we systemically interpret changes in the use of 381 pesticides over 25 years by considering 1591 substance-specific acute toxicity threshold values for eight nontarget species groups. We find that the toxicity of applied insecticides to aquatic invertebrates and pollinators has increased considerably-in sharp contrast to the applied amount-and that this increase has been driven by highly toxic pyrethroids and neonicotinoids, respectively. We also report increasing applied toxicity to aquatic invertebrates and pollinators in genetically modified (GM) corn and to terrestrial plants in herbicide-tolerant soybeans since approximately 2010. Our results challenge the claims of a decrease in the environmental impacts of pesticide use.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Produtos Agrícolas , Invertebrados/efeitos dos fármacos , Praguicidas/toxicidade , Plantas Geneticamente Modificadas , Plantas/efeitos dos fármacos , Animais , Herbicidas/toxicidade , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Piretrinas/toxicidade , Soja , Zea mays
13.
An Acad Bras Cienc ; 93(1): e20190425, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33825789

RESUMO

Conyza species are important weeds in global agriculture, especially due to their capacity to evolve resistance to multiple herbicide mechanisms of action. We aimed to evaluate the frequency and distribution of resistance to glyphosate and chlorimuron-ethyl in Conyza spp. populations from Brazil. Seed samples were collected from grain production areas across nine Brazilian states over five consecutive years (2014 to 2018). Prior to resistance monitoring trials, dose-response assays were conducted to determine a single dose of glyphosate or chlorimuron-ethyl to discriminate resistant and susceptible populations. Resistance monitoring based on plant responses to the application of discriminatory doses of glyphosate (960 g ha-1) or chlorimuron-ethyl (20 g ha-1). Populations were classified as resistant, moderately resistant, or susceptible to either herbicide. While glyphosate resistance was highly frequent (71.2%) in all the five years, chlorimuron-ethyl resistant populations occurred at 39.8% of the total. The frequency of multiple resistance to both herbicides (35.3%) was proportional to the occurrence of chlorimuron-ethyl resistance (39.6%). Resistance to glyphosate and to chlorimuron-ethyl were found across all states evaluated.


Assuntos
Conyza , Herbicidas , Brasil , Glicina/análogos & derivados , Glicina/farmacologia , Resistência a Herbicidas , Herbicidas/farmacologia
14.
FEMS Microbiol Ecol ; 97(5)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33784375

RESUMO

The frequent exposure of agricultural soils to pesticides can lead to microbial adaptation, including the development of dedicated microbial populations that utilize the pesticide compound as a carbon and energy source. Soil from an agricultural field in Halen (Belgium) with a history of linuron exposure has been studied for its linuron-degrading bacterial populations at two time points over the past decade and Variovorax was appointed as a key linuron degrader. Like most studies on pesticide degradation, these studies relied on isolates that were retrieved through bias-prone enrichment procedures and therefore might not represent the in situ active pesticide-degrading populations. In this study, we revisited the Halen field and applied, in addition to enrichment-based isolation, DNA stable isotope probing (DNA-SIP), to identify in situ linuron-degrading bacteria in linuron-exposed soil microcosms. Linuron dissipation was unambiguously linked to Variovorax and its linuron catabolic genes and might involve the synergistic cooperation between two species. Additionally, two novel linuron-mineralizing Variovorax isolates were obtained with high 16S rRNA gene sequence similarity to strains isolated from the same field a decade earlier. The results confirm Variovorax as a prime in situ degrader of linuron in the studied agricultural field soil and corroborate the genus as key for maintaining the genetic memory of linuron degradation functionality in that field.


Assuntos
Herbicidas , Linurona , Bélgica , Biodegradação Ambiental , DNA Bacteriano/genética , Isótopos , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo
15.
Environ Int ; 152: 106493, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33740675

RESUMO

Florida manatees depend on freshwater environments as a source of drinking water and as warm-water refuges. These freshwater environments are in direct contact with human activities where glyphosate-based herbicides are being used. Glyphosate is the most used herbicide worldwide and it is intensively used in Florida as a sugarcane ripener and to control invasive aquatic plants. The objective of the present study was to determine the concentration of glyphosate and its breakdown product, aminomethylphosphonic acid (AMPA), in Florida manatee plasma and assess their exposure to manatees seeking a warm-water refuge in Crystal River (west central Florida), and in South Florida. We analyzed glyphosate's and AMPA's concentrations in Florida manatee plasma (n = 105) collected during 2009-2019 using HPLC-MS/MS. We sampled eight Florida water bodies between 2019 and 2020, three times a year: before, during and after the sugarcane harvest using grab samples and molecular imprinted passive Polar Organic Chemical Integrative Samplers (MIP-POCIS). Glyphosate was present in 55.8% of the sampled Florida manatees' plasma. The concentration of glyphosate has significantly increased in Florida manatee samples from 2009 until 2019. Glyphosate and AMPA were ubiquitous in water bodies. The concentration of glyphosate and AMPA was higher in South Florida than in Crystal River, particularly before and during the sugarcane harvest when Florida manatees depend on warm water refuges. Based on our results, Florida manatees were chronically exposed to glyphosate and AMPA, during and beyond the glyphosate applications to sugarcane, possibly associated with multiple uses of glyphosate-based herbicides for other crops or to control aquatic weeds. This chronic exposure in Florida water bodies may have consequences for Florida manatees' immune and renal systems which may further be compounded by other environmental exposures such as red tide or cold stress.


Assuntos
Herbicidas , Trichechus manatus , Animais , Glicina/análogos & derivados , Herbicidas/análise , Organofosfonatos , Espectrometria de Massas em Tandem
16.
Environ Monit Assess ; 193(4): 194, 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33728504

RESUMO

The speed of the sorption reaction alters the bioavailability of herbicides in the soil and, consequently, the transport and transformation processes of the molecule in the environment. In this research, the sorption kinetics of sulfometuron-methyl was evaluated in different Brazilian soils in which sugarcane is grown. The sorption speed was carried out by the batch equilibrium method. The amount of sulfometuron-methyl adsorbed and remaining in the soil solution was used to build kinetic models in fifteen soils. Pearson's correlation coefficients were determined between maximum sorption capacity and soil properties. The pseudo-second-order model presented the best fit to report the sorption kinetics of sulfometuron-methyl in soils. The sorption equilibrium time varied between 69.1 and 524.7 min. The properties of cation exchange capacity (CEC), soil hydrogenionic potential (pH), and total organic carbon (TOC) affected the sorption kinetics of sulfometuron-methyl. The pH showed a negative correlation with the maximum adsorption capacity at equilibrium, while TOC and CEC positively correlated with the maximum adsorption. The results demonstrate that the sorption speed of sulfometuron-methyl varies between soils; this must be considered when defining the rate of use of the herbicide for weed control, minimizing the risk of environmental contamination.


Assuntos
Herbicidas , Poluentes do Solo , Adsorção , Brasil , Monitoramento Ambiental , Cinética , Solo , Poluentes do Solo/análise , Compostos de Sulfonilureia
17.
Pestic Biochem Physiol ; 173: 104794, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33771265

RESUMO

Climate change will be an additional issue to the challenge to manage herbicide resistant weeds. This work investigated the impact of three temperature regimes (10/5, 20/15 and 30/25 °C) on the efficacy, foliar retention, absorption and translocation of fomesafen, protoporphyrinogen oxidase (PPO) inhibitor, and imazamox, acetolactate synthase (ALS) inhibitor, between two Euphorbia heterophylla populations, one susceptible (S) and one multiple PPO and ALS resistant (R). The R population went from 5 (fomesafen) and 12 (imazamox) times more resistant than the S population at 10/5 °C to more than 100 times to both herbicides at 20/15 and 30/25 °C. Leaf retention of fomesafen was not affected by temperature; however, imazamox retention was less at 10/5 and 20/15 °C than at 30/25 °C, and the R population always retained less imazamox than the S population. 14C-fomesafen absorption was similar between populations, but lower amounts were absorbed at 10/5 °C regardless of the evaluation time. Recovered 14C-imazamox rates decreased in both populations as the evaluation time increased, ranging from 82 to 92% at 6 h after treatment (HAT), and from 47 to 76% at 48 HAT, depending on the temperature regime. The 14C-imazamox losses were greater from 24 HAT in R plants grown at 30/25 °C and in all temperature regimes at 48 HAT. Although both populations translocated large amounts of imazamox, the S population distributed it in the rest of the plant (33%) and roots (15%), while the R population kept it mainly on the treated leaf (24%) or lost ~20% more herbicide than S population at 48 HAT, indicating the need for further studies on root exudation between these populations. Low temperatures reduced resistance levels to fomesafen and imazamox in E. heterophylla, suggesting that temperature influences the expression of the mechanisms that govern this multiple resistance.


Assuntos
Acetolactato Sintase , Euphorbia , Herbicidas , Benzamidas , Resistência a Herbicidas , Herbicidas/farmacologia , Imidazóis , Temperatura
18.
Pestic Biochem Physiol ; 173: 104795, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33771266

RESUMO

Acetohydroxy acid synthase (AHAS)-inhibiting herbicides are one of the most commonly used herbicides for controlling the growth of Sagittaria trifolia L. in paddy fields in Northeastern China. In this study, we collected five suspected resistant populations of S. trifolia (R1-R5) from three different provinces of Northeastern China. The results of whole-plant bioassays revealed that those populations showed high level of resistance to bensulfuron-methyl with resistance index (GR50 R/S) ranging from 39.90 to 88.50. The results of AHAS-activity assays were consistent with the results of the whole-plant bioassays. The AHAS gene analysis showed that R2 and R3 populations contained Pro-197-Leu mutations that were highly resistant to penoxsulam; R1 and R4 populations contained Pro-197-Ser mutations that were highly resistant to bispyribac­sodium; R5 population contained Trp-574-Leu mutation that showed high resistance to IMI, PT, PTB and SU herbicides. The AHAS with resistance mutations showed less sensitivity to feedback inhibition by BCAAs and R genotypes had increased free BCAAs.


Assuntos
Acetolactato Sintase , Herbicidas , Sagittaria , Acetolactato Sintase/genética , China , Resistência a Herbicidas/genética , Herbicidas/farmacologia , Mutação
19.
Environ Sci Technol ; 55(8): 4720-4728, 2021 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-33761249

RESUMO

Current approaches are often limited to evaluating the contribution of pesticide dissipation processes in water-sediment systems as both degradation and phase transfer, that is, sorption-desorption, contribute to the apparent decrease of pesticide concentration. Here, the dissipation of widely used herbicides acetochlor and S-metolachlor was examined in laboratory by water-sediment microcosm experiments under oxic and anoxic conditions. Compound-specific isotope analysis (CSIA) emphasized insignificant carbon isotope fractionation in the sediment, indicating prevailing pesticide degradation in the water phase. Conceptual modeling accounting for phase transfer and biodegradation indicated that biodegradation may be underestimated when phase transfer is not included. Phase transfer does not affect carbon isotope fractionation for a wide spectrum of molecules and environmental conditions, underscoring the potential of pesticide CSIA as a robust approach to evaluate degradation in water-sediment systems. CSIA coupled with the identification of transformation products by high-resolution tandem mass spectrometry suggests the degradation of acetochlor and S-metolachlor to occur via nucleophilic substitution and the predominance of oxalinic acids as transformation products under both anoxic and oxic conditions. Altogether, combining the pesticide CSIA, the identification of transformation products, and the use of conceptual phase-transfer models improves the interpretation of pesticide dissipation in water-sediment systems.


Assuntos
Herbicidas , Praguicidas , Poluentes Químicos da Água , Biodegradação Ambiental , Isótopos de Carbono , Herbicidas/análise , Água , Poluentes Químicos da Água/análise
20.
Life Sci ; 275: 119350, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33737081

RESUMO

AIM: Exposure to pesticides and consumption of high-fat diets are widespread in society. Reports have shown that exposure to glyphosate and a high-fat diet can cause gastrointestinal disorders and increase susceptibility to obesity. Thus, this study evaluated the impacts of perinatal exposure to glyphosate followed by consumption of a high-fat diet in adulthood on the histology and morphometry of jejunums and enteric nervous system of C57BL/6 mice. MATERIAL AND METHODS: After mating, 20 C57BL/6 female mice were separated into a control group (CG) and a glyphosate group (GLY) that received water with 0.5% glyphosate. After the lactation period, some male offspring were randomly separated into CG-SD and GLY-SD (standard diet) groups or CG-HD and GLY-HD (high-fat diet) groups. After 12 weeks, jejunum samples were collected and submitted to histological analysis. KEY FINDINGS: Indirect exposure to glyphosate changed the morphometry of the intestinal wall, increased the proportion of intraepithelial lymphocytes (IELs) and goblet cells, and altered the area occupied by collagen fibers. The hyperlipidemic diet hypertrophied the jejunal total wall, total muscular and submucosal layers, decreased IELs, and increased the proportion of goblet cells. GLY-HD mice had shallower crypts, shorter villi, and less goblet cells and IELs than mice from GLY-SD group. GLY-HD also showed an increased number of neurons in myenteric and submucosal plexuses. Groups exposed to glyphosate and/or fed a high-fat diet had atrophied submucosal neurons. SIGNIFICANCE: This study suggests that perinatal glyphosate exposure combined with a high-fat diet in adulthood increases the risk of jejunum inflammation and dysfunction.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Glicina/análogos & derivados , Herbicidas/efeitos adversos , Jejuno/efeitos dos fármacos , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Animais , Feminino , Glicina/efeitos adversos , Células Caliciformes/efeitos dos fármacos , Células Caliciformes/patologia , Jejuno/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Gravidez
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