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1.
Ecotoxicol Environ Saf ; 203: 111046, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888614

RESUMO

Agricultural pesticides serve as effective controls of unwanted weeds and pests. However, these same chemicals can exert toxic effects in non-target organisms. To determine chemical modes of action, the toxicity ratio (TR) and critical body residues (CBRs) of 57 pesticides were calculated for Daphnia magna. Results showed that the CBR values of inert compounds were close to a constant while the CBR values of pesticides varied over a wider range. Although herbicides are categorized as specifically-acting compounds to plants, herbicides did not exhibit excess toxicity to Daphnia magna and were categorized as inert compounds with an average logTR = 0.41, which was less than a threshold of one. Conversely, fungicides and insecticides exhibited strong potential for toxic effects to Daphnia magna with an average logTR >2. Many of these chemicals act via disruption of the nervous, respiratory, or reproductive system, with high ligand-receptor binding activity which leads to higher toxicity for Daphnia magna. Molecular docking using acetylcholinesterase revealed that fungicides and insecticides bind more easily with the biological macromolecule when compared with inert compounds. Quantitative structure-activity relationship (QSAR) analysis revealed that the toxicity of fungicides was mainly dependent upon the heat of formation and polar surface area, while the toxicity of insecticides was more related to hydrogen-bond properties. This comprehensive analysis reveals that there are specific differences in toxic mechanisms between fungicides and insecticides. These results are useful for determining relative risk associated with pesticide exposure to aquatic crustaceans, such as Daphnia magna.


Assuntos
Daphnia/efeitos dos fármacos , Modelos Biológicos , Praguicidas/química , Praguicidas/toxicidade , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade , Acetilcolinesterase/metabolismo , Animais , Daphnia/metabolismo , Relação Dose-Resposta a Droga , Fungicidas Industriais/química , Fungicidas Industriais/toxicidade , Herbicidas/química , Herbicidas/toxicidade , Ligação de Hidrogênio , Inseticidas/química , Inseticidas/toxicidade , Simulação de Acoplamento Molecular , Resíduos de Praguicidas/metabolismo , Relação Quantitativa Estrutura-Atividade
2.
Bull Environ Contam Toxicol ; 105(4): 595-601, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32862252

RESUMO

The residual characteristics and risk assessment with respect to cyazofamid and its metabolite 4-chloro-5-p-tolylimidazole-2-carbonitrile were monitored in case of Korean cabbage at different preharvest intervals during a greenhouse trial. The 0.02 kg a.i/ha of cyazofamid was sprayed twice on seven-day intervals (i.e., on day 0, 7, 14, and 21 before harvest). The liquid chromatography-tandem mass spectrometry analysis was used to monitor the residual amount of fungicide. The matrix-matched calibration curves with respect to the cyazofamid in Korean cabbage exhibited good linearity (R2 ≥ 0.999) and acceptable recoveries of 84.1%-114.9%. The biological half-life of cyazofamid in Korean cabbage was 3.18 days. During the treatment, the preharvest residue of cyazofamid in Korean cabbage 14 days before harvest (0.80 mg/kg) was lower than that specified by the MFDS-MRL (Ministry of Food and Drug Safety-Maximum Residue Limit, 2.0 mg/kg) and should be recommended as the safe preharvest-interval application limit. The hazard quotient showed low toxicity (70.58%) during the risk assessment study of cyazofamid.


Assuntos
Fungicidas Industriais/toxicidade , Imidazóis/toxicidade , Resíduos de Praguicidas/toxicidade , Sulfonamidas/toxicidade , Brassica/química , Cromatografia Líquida/métodos , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Meia-Vida , Imidazóis/metabolismo , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/metabolismo , República da Coreia , Medição de Risco , Sulfonamidas/metabolismo
3.
Chemosphere ; 258: 127217, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32535437

RESUMO

The widespread use of pesticides has received increasing attention in regulatory agencies because their extensive overuse and various adverse effects on all living organisms. Organizations such as EPA and ECHA have published laws that pesticides should be fully evaluated before bring them to market. In the present study, we evaluated the pesticides toxicity using the Quantitative Structural-Activity Relationship (QSAR) method. The models for the single class pesticides (herbicides, insecticides and fungicides) as well as the general class pesticides (the combined dataset plus some microbicides, molluscicides, etc.) were developed using the Genetic Algorithm and Multiple Linear Regression method. The internal and external validation results suggested that all the obtained models were stable and predictive. According to the modeling descriptors, the lipophilic descriptors contributed positively while all the electrotopological state descriptors showed a negative contribution, their presences in every model verified the conspicuous influence of molecular lipophilicity and hydrophilicity on the pesticides toxicity. However, the influence of topological structure descriptors was different and varies with the physiochemical information they encode. Finally, the models presented in this paper would help assess the pesticides toxicity against Americamysis bahia, shorten test time, and reduce the cost of pesticides risk assessment.


Assuntos
Crustáceos/efeitos dos fármacos , Modelos Teóricos , Praguicidas/química , Praguicidas/toxicidade , Animais , Bases de Dados Factuais , Fungicidas Industriais/química , Fungicidas Industriais/toxicidade , Herbicidas/química , Herbicidas/toxicidade , Interações Hidrofóbicas e Hidrofílicas , Inseticidas/química , Inseticidas/toxicidade , Modelos Lineares , Relação Quantitativa Estrutura-Atividade
4.
J Chromatogr A ; 1622: 461104, 2020 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-32376023

RESUMO

The coexistence of the anilinopyrimidine fungicides pyrimethanil (PYR) and cyprodinil (CYP), and suspected metabolites in wine samples was investigated by liquid chromatography (LC) with tandem mass spectrometry (MS/MS), based on triple quadrupole (QqQ) and quadrupole time-of-flight (QTOF) MS instruments. For the first time, quantitative data obtained after solid-phase extraction (SPE) of wine samples have demonstrated the systematic presence of 4-hydroxyanilino derivatives of PYR and CYP in wines containing residues of parent fungicides, at concentrations from 0.2 to 58 ng mL-1. Higher concentration ratios (hydroxylated derivative/active fungicide) were measured in red than in white wines, particularly in case of PYR. On average, the concentrations of PYR-4OH were twice those measured for PYR in red wines. A targeted search of hydroxyl derivatives in wine extracts by LC-QTOF-MS showed the existence of additional hydroxylation positions in the pyrimidine ring and/or in the alkyl substituents bond to this cycle in the structure of both anti-botrytis fungicides. Moreover, free and glycosylated forms of the hydroxylated metabolites for both fungicides coexist in wine samples. In case of CYP, it is proved that hydroxylated and glycosylated metabolites are already present in grapes before vinification.


Assuntos
Fungicidas Industriais/análise , Resíduos de Praguicidas/análise , Pirimidinas/análise , Vinho/análise , Cromatografia Líquida , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Resíduos de Praguicidas/química , Resíduos de Praguicidas/isolamento & purificação , Resíduos de Praguicidas/metabolismo , Pirimidinas/química , Pirimidinas/metabolismo , Extração em Fase Sólida , Espectrometria de Massas em Tandem
5.
Chemosphere ; 254: 126807, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32334257

RESUMO

Photolysis of pesticides has been widely investigated for evaluating their environmental behavior and agricultural effectiveness after crop spraying. However, little information about the effects of the water-soluble substances in atmosphere on photodegradation of pesticides is available. In current study, we found that photolysis of applied dithianon fungicides on real plant leaves was much faster than that in sealed stock aqueous suspensions under simulated sunlight. To simulate the natural conditions, for the first time, photodegradation of dithianon in air-saturated solutions containing typical dissolved atmospheric substances (DAS) including CO2 (HCO3-/CO32-), NO2 (NO3-), Fe3+ (Fe3+-complexes), and humic-like substances (HULIS) exposed to simulated solar irradiations were carried out in lab-scale. Fulvic acid (FA) was used as a surrogate for atmospheric HULIS in this study. The dithianon photodegradation was significantly enhanced in the presence of DAS and the photo-generated reactive species such as ·OH, 1O2, CO3·- and 3FA∗ play important roles according to the results of reactive species quenching, electron spin resonance spectroscopy, and laser flash photolysis experiments. Moreover, the photodegraded intermediates and final products of dithianon on plant leaves have been identified by HPLC-MS analysis, and its possible photodegradation pathways were proposed. This work indicated that, except for direct photolysis, indirect photosensitive degradation induced by the dissolved photo-active substances in atmosphere should be considered for evaluating the degradation of the applied pesticides on crops.


Assuntos
Fungicidas Industriais/metabolismo , Folhas de Planta/metabolismo , Poluentes Químicos da Água/metabolismo , Benzopiranos , Cromatografia Líquida de Alta Pressão , Fungicidas Industriais/química , Substâncias Húmicas/análise , Cinética , Luz , Fotólise , Folhas de Planta/química , Plantas , Luz Solar , Água/química , Poluentes Químicos da Água/química
6.
Nat Commun ; 11(1): 1608, 2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-32231209

RESUMO

The emerging resistance of crop pathogens to fungicides poses a challenge to food security and compels discovery of new antifungal compounds. Here, we show that mono-alkyl lipophilic cations (MALCs) inhibit oxidative phosphorylation by affecting NADH oxidation in the plant pathogens Zymoseptoria tritici, Ustilago maydis and Magnaporthe oryzae. One of these MALCs, consisting of a dimethylsulfonium moiety and a long alkyl chain (C18-SMe2+), also induces production of reactive oxygen species at the level of respiratory complex I, thus triggering fungal apoptosis. In addition, C18-SMe2+ activates innate plant defense. This multiple activity effectively protects cereals against Septoria tritici blotch and rice blast disease. C18-SMe2+ has low toxicity in Daphnia magna, and is not mutagenic or phytotoxic. Thus, MALCs hold potential as effective and non-toxic crop fungicides.


Assuntos
Cátions/farmacologia , Produtos Agrícolas/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Doenças das Plantas/prevenção & controle , Substâncias Protetoras/farmacologia , Animais , Ascomicetos/efeitos dos fármacos , Cátions/química , Daphnia/efeitos dos fármacos , Descoberta de Drogas , Grão Comestível/microbiologia , Fibroblastos/efeitos dos fármacos , Fungicidas Industriais/química , Humanos , Mitocôndrias/efeitos dos fármacos , Oryza/microbiologia , Doenças das Plantas/microbiologia , Substâncias Protetoras/química , Triticum/microbiologia , Ustilago/efeitos dos fármacos
7.
PLoS One ; 15(4): e0231315, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32315346

RESUMO

Although fungicides could be the best solution in combating fungal infections in crops, however, the phytotoxic level of fungicides to the crops should be tested first to ensure that it is safe for the crops. Moreover, nanocarrier systems of fungicides could play a significant role in the advancement of crop protection. For this reason, chitosan was chosen in the present study as a nanocarrier for fungicides of hexaconazole and/or dazomet in the development of a new generation of agronanofungicides with a high antifungal potent agent and no phytotoxic effect. Hence, the encapsulation of fungicides into the non-toxic biopolymer, chitosan was aims to reduce the phytotoxic level of fungicides. In the present study, the in vivo phytotoxicity of chitosan-fungicides nanoparticles on the physiological and vegetative growth of oil palm seedlings was evaluated in comparison to its pure fungicides as well as the conventional fungicides. The results revealed the formation of chitosan-fungicides nanoparticles could reduce the phytotoxic effect on oil palm seedlings compared to their counterparts, pure fungicides. The chitosan-fungicides nanoparticles were seen to greatly reduce the phytotoxic effect compared to the conventional fungicides with the same active ingredient.


Assuntos
Arecaceae/efeitos dos fármacos , Quitosana/química , Proteção de Cultivos , Fungicidas Industriais/toxicidade , Doenças das Plantas/prevenção & controle , Plântula/efeitos dos fármacos , Arecaceae/crescimento & desenvolvimento , Fungicidas Industriais/química , Nanopartículas/química , Nanopartículas/toxicidade , Plântula/crescimento & desenvolvimento , Tiadiazinas/química , Tiadiazinas/toxicidade , Triazóis/química , Triazóis/toxicidade
8.
PLoS Pathog ; 16(3): e1008323, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32163521

RESUMO

Fusarium is a genus of filamentous fungi that includes species that cause devastating diseases in major staple crops, such as wheat, maize, rice, and barley, resulting in severe yield losses and mycotoxin contamination of infected grains. Phenamacril is a novel fungicide that is considered environmentally benign due to its exceptional specificity; it inhibits the ATPase activity of the sole class I myosin of only a subset of Fusarium species including the major plant pathogens F. graminearum, F. asiaticum and F. fujikuroi. To understand the underlying mechanisms of inhibition, species specificity, and resistance mutations, we have determined the crystal structure of phenamacril-bound F. graminearum myosin I. Phenamacril binds in the actin-binding cleft in a new allosteric pocket that contains the central residue of the regulatory Switch 2 loop and that is collapsed in the structure of a myosin with closed actin-binding cleft, suggesting that pocket occupancy blocks cleft closure. We have further identified a single, transferable phenamacril-binding residue found exclusively in phenamacril-sensitive myosins to confer phenamacril selectivity.


Assuntos
Cianoacrilatos/química , Proteínas Fúngicas/química , Fungicidas Industriais/química , Fusarium/enzimologia , Miosina Tipo I/química , Cianoacrilatos/farmacologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fungicidas Industriais/farmacologia , Fusarium/química , Fusarium/efeitos dos fármacos , Fusarium/genética , Miosina Tipo I/genética , Miosina Tipo I/metabolismo , Doenças das Plantas/microbiologia , Triticum/microbiologia , Zea mays/microbiologia
9.
J Chromatogr A ; 1620: 461004, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32143875

RESUMO

In the present study, a fast multiresidue method determining three novel fungicides fenpicoxamid, isofetamid, and mandestrobin in cereals was developed and validated for the first time using ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Samples were extracted by QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) methodology, and cleaned up using the disposable pipette extraction (DPX) tips containing primary secondary amine (PSA) and silica gel modified with zirconium oxide (Z-Sep) in less than 1 min. Linearity (r > 0.99) of three fungicides in the calibration range of 0.001-0.1 µg mL-1 was satisfactory. Mean recoveries (n = 15) from all matrices were between 84.8% and 100.3% as the corresponding intra-day and inter-day relative standard deviations (RSDs) were less than 10.6%. Limits of quantitation (LOQs) of all analytes in different matrices were defined at 0.01 mg kg-1. The results indicate this method can serve as a sensitive and rapid approach to monitoring contents of fenpicoxamid, isofetamid, and mandestrobin in cereals.


Assuntos
Acetamidas/análise , Cromatografia Líquida de Alta Pressão/métodos , Grão Comestível/química , Fungicidas Industriais/análise , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Tiofenos/análise , Fracionamento Químico/instrumentação , Fungicidas Industriais/química , Fungicidas Industriais/isolamento & purificação , Lactonas/análise , Lactonas/química , Lactonas/isolamento & purificação , Resíduos de Praguicidas/química , Resíduos de Praguicidas/isolamento & purificação , Piridinas/análise , Piridinas/química , Piridinas/isolamento & purificação , Zircônio/química
10.
Food Chem ; 317: 126424, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32088405

RESUMO

In this study, a simple, efficient, and green effervescence tablet-assisted microextraction method based on the solidification of deep eutectic solvent (ETA-ME-SDES) was developed to determine picoxystrobin, pyraclostrobin, and trifloxystrobin in water, juice, wine, and vinegar samples by HPLC. An eco-friendly, hydrophobic, deep eutectic solvent (DES, acting as the extraction solvent) was synthesized by thymol and octanoic acid in the molar ratio of 1:5. The extraction solvent dispersed in sample solutions with the assistance of pH adjustment and effervescence reaction, and was collected after solidification in an ice bath. Several essential conditions, including the type and the volume of DESs, the amount of ammonia hydroxide, and the components of effervescence tablets were optimized. The limits of detection ranged from 0.15 to 0.38 µg L-1. Extraction recovery ranged from 77.4 to 106.9%. The proposed method was successful in determining the amount of strobilurin fungicides in water, juice, wine, and vinegar samples.


Assuntos
Ácido Acético/análise , Cromatografia Líquida de Alta Pressão , Sucos de Frutas e Vegetais/análise , Fungicidas Industriais/análise , Estrobilurinas/análise , Poluentes Químicos da Água/análise , Vinho/análise , Acetatos/análise , Fungicidas Industriais/química , Concentração de Íons de Hidrogênio , Iminas/análise , Limite de Detecção , Microextração em Fase Líquida/métodos , Sais/química , Estrobilurinas/química , Poluentes Químicos da Água/química
11.
Biochemistry (Mosc) ; 85(Suppl 1): S154-S176, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32087058

RESUMO

In this review, we present the data on the natural occurrence of chitin and its partially or fully deacetylated derivative chitosan, as well as their properties, methods of modification, and potential applications of derivatives with bactericidal, fungicidal, and antioxidant activities. The structure and physicochemical characteristics of the polymers, their functions, and features of chitin microbial synthesis and degradation, including the processes occurring in nature, are described. New data on the hydrolytic microorganisms capable of chitin degradation under extreme conditions are presented. Special attention is focused on the effect of physicochemical characteristics of chitosan, including molecular weight, degree of deacetylation, polydispersity index, and number of amino group derivatives (quaternized, succinyl, etc.) on the antimicrobial and antioxidant properties of modified polymers that can be of particular interest for biotechnology, medicine, and agriculture. Analysis of the available literature data confirms the importance of fundamental research to broaden our knowledge on the occurrence of chitin and chitosan in nature, their role in global biosphere cycles, and prospects of applied research aimed at using chitin, chitosan, and their derivatives in various aspects of human activity.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antioxidantes/farmacologia , Quitosana/análogos & derivados , Quitosana/farmacologia , Fungicidas Industriais/farmacologia , Antibacterianos/química , Antibacterianos/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Antioxidantes/química , Antioxidantes/metabolismo , Bactérias/metabolismo , Biotecnologia , Quitosana/química , Quitosana/metabolismo , Proteção de Cultivos , Descoberta de Drogas , Fungicidas Industriais/química , Fungicidas Industriais/economia , Fungicidas Industriais/metabolismo , Humanos , Hidrólise , Peso Molecular , Polímeros
12.
J Agric Food Chem ; 68(8): 2418-2425, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32011876

RESUMO

Two biosynthetically related new metabolites, eucalyptacid A (1) and eucalactam B (2), along with six known compounds (3-8), eugenitol (3), cytosporone C (4), 4-hydroxyphenethyl alcohol (5), 1-(4-hydroxyphenyl)ethane-1,2-diol (6), N-(2-hydroxy-2-phenylethyl)acetamide (7), and phomopene (8), were isolated from the solid rice cultures of the endophytic fungus Diaporthe eucalyptorum KY-9 that had been isolated from Melia azedarach. Also, two further new derivatives (2a, 2b) were prepared from 2. The structures were elucidated by exhaustive analysis of NMR and ESIMS data and chemical methods such as Marfey's protocol. Compound 1 was identified as a rare polyketide fatty acid, (8E)-3,5,11-trihydroxy-2,10,12-trimethyltetradecenoic acid, and 2 was determined to be the first cyclic depsipeptide containing the same fatty acid unit as 1 and a Gly-Gly-Thr tripeptide chain. Its N-terminal end is N-acylated by an 11-hydroxy fatty acid with a branch alkyl chain of 14:1. The 11-hydroxyl group connects to the carboxylic group of the C-terminal amino acid to form a 22-membered lactone ring. A hypothetical biosynthetic pathway for the new polyketides is proposed. The isolated compounds were assayed for their inhibition against four plant pathogenic fungi, Alternaria solani, Botrytis cinerea, Fusarium solani, and Gibberella saubinettii. Compounds 1, 4, 6, and 7 exhibited antifungal activities against Alternaria solani, with minimal inhibitory concentration (MIC) values from 6.25 to 50 µM. Thus, strain KY-9 represents an untapped source for the development of biological control agents to prevent the infection of pathogenic fungus A. solani.


Assuntos
Fungicidas Industriais/metabolismo , Fungicidas Industriais/farmacologia , Melia azedarach/microbiologia , Saccharomycetales/química , Alternaria/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Fungicidas Industriais/química , Fungicidas Industriais/isolamento & purificação , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Saccharomycetales/isolamento & purificação , Saccharomycetales/metabolismo
13.
J Environ Sci Health B ; 55(5): 501-507, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32036766

RESUMO

Controlled release (CR) nanoformulations of Mancozeb (Manganese-zinc double salt of N, N-bisdithiocarbamic acid), a protective fungicide, have been developed using poly (ethylene glycols) (PEGs) based functionalized amphiphilic copolymers and evaluated for the management of early blight in tomato. During the field experiment, it was observed that number of infected leaflets/plants were less in developed formulation treated plants as compared to commercial products. Number of infected leaflets per plant was 2.40-4.60 and the number of fruits per plant were 6.40-9.00 at 50 mg L-1, whereas at 100 mg L-1, the corresponding numbers were 2.10-4.10 and 6.30-9.10 respectively. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, sufficient amount of active ingredient remains available for a reasonable period of time after application leading to reduced number of applications of pesticide.


Assuntos
Fungicidas Industriais/farmacologia , Lycopersicon esculentum/microbiologia , Maneb/química , Maneb/farmacologia , Nanoestruturas/química , Zineb/química , Zineb/farmacologia , Alternaria/efeitos dos fármacos , Alternaria/patogenicidade , Fungicidas Industriais/química , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Polietilenoglicóis/química , Polímeros/química
14.
J Colloid Interface Sci ; 566: 383-393, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32018178

RESUMO

Metal-organic frameworks (MOFs) are an emerging class of hybrid inorganic-organic porous materials used in various fields. Considering their excellent performance, MOFs have a considerable application potential in sustainable agriculture. Research projects of MOFs-based platforms for plant protection and nutrition have just started. Environmental stimuli-responsive pesticide release is highly desirable for improved efficacy and decreased side effects. Iron-based MOFs (Fe-MOFs) have a considerable prospect in agriculture as multifunctional materials both for pesticide delivery and plant nutrient replenishment because iron is an essential micronutrient for crop growth. In this work, a simple octahedral Fe-MOFs built from trimers of iron octahedra linked by 1, 3, 5-benzenetricarboxylate (Fe-MIL-100) have been prepared as carriers for fungicide azoxystrobin. Due to the high surface area of 2251 m2/g, the loading content of azoxystrobin into Fe-MIL-100 is satisfactory up to 16.2%. Azoxystrobin-loaded Fe-MOFs (AZOX@Fe-MIL-100) exhibit a pH-responsive initial burst and a subsequent sustained release pattern. Moreover, AZOX@Fe-MIL-100 exhibits good fungicidal activities against two pathogenic fungi-wheat head scab (Fusarium graminearum) and tomato late blight (Phytophthora infestans). The nutritional function of Fe-MIL-100 as iron micronutrient for the enhanced wheat growth was also observed. This research explores the feasibility of MOFs as a platform for potential application in sustainable plant protection.


Assuntos
Antifúngicos/farmacologia , Fungicidas Industriais/farmacologia , Fusarium/efeitos dos fármacos , Estruturas Metalorgânicas/química , Phytophthora infestans/efeitos dos fármacos , Pirimidinas/farmacologia , Estrobilurinas/farmacologia , Antifúngicos/química , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Fungicidas Industriais/química , Concentração de Íons de Hidrogênio , Ferro/química , Ferro/farmacologia , Estruturas Metalorgânicas/farmacologia , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Porosidade , Pirimidinas/química , Estrobilurinas/química , Propriedades de Superfície
15.
J Agric Food Chem ; 68(7): 2116-2123, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986045

RESUMO

Fungal pathogens cause serious crop diseases and decrease crop yields and quality. Polyacetylene alcohols are plant secondary metabolites and bioactive against various pathogenic fungi. They are, however, difficult to synthesize. In the present study, an efficient and highly enantioselective method (>98% ee) was established and employed to achieve the synthesis of the natural C18 polyacetylenes (S,E)-octadeca-1,9-dien-4,6-diyn-3-ol 1, (3R,10R,E)-octadeca-1,8-dien-4,6-diyne-3,10-diol 2, and their analogs. The title compounds were structurally characterized and biologically evaluated for fungicidal activities. The compounds exhibited high potencies against eight pathogenic fungal species tested, such as Colletotrichum gloeosporioiles, Bipolaris sorokiniana, Fusarium graminearum, and Fusarium pseudograminearum, with half-maximum effective concentrations ranging from 8 to 425 µg/mL, being similar to those of the fungicide thiophanate-methyl (3-408 µg/mL). These compounds are potential natural fungicides and fungicide lead candidates for further structural and property improvements.


Assuntos
Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Polímero Poliacetilênico/química , Polímero Poliacetilênico/farmacologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Polímero Poliacetilênico/síntese química , Estereoisomerismo
16.
J Agric Food Chem ; 68(5): 1198-1206, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31928001

RESUMO

In this study, three types of pyraclostrobin formulations (including emulsifiable concentrate (EC), suspension concentrate (SC), and microcapsules (MCs)) were used to control cucumber anthracnose. Pyraclostrobin EC had the highest inhibitory activity against Colletotrichum orbiculare in vitro. Much different from the bioactivity in vitro, pyraclostrobin MCs exhibited the highest control efficacy on cucumber anthracnose both in pot and field experiments. The physicochemical properties (particle size, surface tension) of the spray dilution, their interaction with target leaves (contact angle, adhesional tension, work of adhesion, retention, crystallization) and dissipation dynamic of the active ingredient were found to be highly potential factors that would significantly influence the control efficacy of pesticide formulations. Results showed that the control efficacies of different formulations of pyraclostrobin were determined mainly by the final behavior of the pesticides at the target interface, namely, the retention, crystallization, and dissipation dynamics of active ingredients. This study had revealed crucial factors that would influence the efficacy of different formulations of pyraclostrobin and thus could guide the rational and efficient use of different formulations of pesticides on target crops.


Assuntos
Colletotrichum/efeitos dos fármacos , Cucumis sativus/microbiologia , Composição de Medicamentos/métodos , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Estrobilurinas/química , Estrobilurinas/farmacologia , Colletotrichum/fisiologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/microbiologia
17.
Food Microbiol ; 87: 103395, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948636

RESUMO

Volatile compounds produced by L1 and L8 strains were assayed against mycelia and conidia growth of Monilinia laxa, M. fructicola, M. polystroma, and M. fructigena of stone fruits. Results showed that volatile metabolites inhibited significantly pathogens growth, in particular M. fructigena mycelium growth (70% by L1 and 50% by L8) and M. fructicola conidia germination (85% by L1 and 70% by L8) compared to the control. Moreover, the antagonistic activity was enhanced by the addition of asparagine (120 mg L-1) in the culture media composition. Synthetic pure compounds were tested in vitro on pathogens mycelial and conidia growth and their EC50 values were estimated, confirming 2-phenethyl as the most active compound. For this reason 2-phenethyl and VOCs of both yeast strains were assayed in vivo on cherry, peach, and apricot fruits. Regarding peach fruit, both treatments, yeasts and pure compounds, displayed the best inhibiting action against all the pathogens especially against M. laxa (100% by L1, 84% by L8 and 2-phenethyl). ATR/IR spectroscopy analysis showed how VOCs produced by both strains increase the fruit waxes complexity reducing the pathogens attack so playing an essential role in the antagonistic activity of both yeast strains and on fruit structural composition.


Assuntos
Ascomicetos/química , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Compostos Orgânicos Voláteis/farmacologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Frutas/microbiologia , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Prunus persica/microbiologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo
18.
J Agric Food Chem ; 68(8): 2306-2315, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31995378

RESUMO

Neocryptolepine is an alkaloid isolated from traditional African herbal medicine Cryptolepis sanguinolenta, and its broad spectrum of biological activities has been illuminated in past decades. In this study, neocryptolepine and its derivatives (1-49) were designed and synthesized from economical and readily available starting materials. Their structures were confirmed by proton nuclear magnetic resonance, carbon nuclear magnetic resonance, and mass spectrometry. The synthesized compounds were screened for their antifungal profile against six agriculturally important fungi Rhizoctonia solani, Botrytis cinerea (B. cinerea), Fusarium graminearum, Mycosphaerella melonis, Sclerotinia sclerotiorum, and Magnaporthe oryzae. The results of in vitro assay revealed that compounds 5, 21, 24, 35, 40, 45, and 47 presented remarkable antifungal activity against the fungi tested with EC50 values lower than 1 µg/mL. Significantly, compound 24 displayed the most effective inhibitory potency against B. cinerea (EC50 = 0.07 µg/mL), and the data from in vivo experiments revealed that compound 24 demonstrated comparable protective activity with the positive control boscalid. Preliminary mechanism studies indicated that compound 24 showed impressive spore germination inhibitory effectiveness and lower cytotoxicity than azoxystrobin, imparted on normal function of the cell membrane and cell wall, and arrested the normal function of the nucleus. Besides the excellent inhibitory activity against agriculturally important phytopathogenic fungi tested, the designed assemblage possesses several benefits with a high profile of variation in synthesized molecules, the ease of synthesis, and good cost-effectiveness of commercially available synthetic reagents, all of these have highlighted the potential worth of compound 24 as a new and highly efficient agricultural fungicide.


Assuntos
Antifúngicos/farmacologia , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Antifúngicos/síntese química , Antifúngicos/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Estrutura Molecular , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/crescimento & desenvolvimento , Relação Estrutura-Atividade
19.
J Agric Food Chem ; 68(1): 77-87, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31794210

RESUMO

Soybeans (Glycine max) (V3 stage) were sprayed once with nanoparticles (NPs) of AgO, B, CeO, CuO, MnO, MoO3, SiO, TiO, or ZnO and exposed to Fusarium virguliforme, the cause of sudden death syndrome. Up to 80% root rot was observed in greenhouse experiments. However, NP CuO, B, MoO3, or ZnO reduced the root rot severity by 17-25%. Infected roots and shoots had significant changes in B, Mg, P, S, Si, and Zn, but NP treatment restored levels to that of the healthy control. For example, the increased root Mg and Mn contents induced by disease were reversed by NP B and Mn amendments. In vitro assays found that the NPs did not inhibit the pathogen. This, along with the restoration of altered nutrient levels in the plant tissue, suggests that modulated plant nutrition increased disease defense. Treatment of seedlings with nanoscale micronutrients may be a new tool in promoting soybean health.


Assuntos
Fungicidas Industriais/farmacologia , Nanopartículas Metálicas/análise , Metais/farmacologia , Óxidos/farmacologia , Doenças das Plantas/prevenção & controle , Soja/efeitos dos fármacos , Fungicidas Industriais/química , Fusarium/efeitos dos fármacos , Fusarium/fisiologia , Metais/química , Óxidos/química , Doenças das Plantas/microbiologia , Soja/fisiologia
20.
J Sci Food Agric ; 100(3): 936-944, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31487041

RESUMO

BACKGROUND: This study investigates the efficacy of short peptides secreted by Bacillus subtilis for fungal inhibition in fresh-cut pumpkin and for maintaining its shelf life. RESULTS: Low-molecular-weight filtrate (LC < 1000 Da) of B. subtilis culture (BC) significantly lowered the total number of molds on fresh-cut pumpkin compared with the untreated control and a BC group after storage. Low-molecular-weight filtrate prevented the deterioration of sensory quality in a pumpkin incision, and reduced pectinase activity. It also inhibited the growth of Phytophthora capsici and Penicillium chrysogenum, and the activity of ß-1,3-glucan synthase (GS) secreted by both molds. Fifty-seven GS-inhibiting peptides were screened from 95 LC peptides with two to five amino acid residues. The two most potent peptides, AWYW and HWWY, had strongly suppressive effects on the growth of P. capsici and P. chrysogenum. CONCLUSION: Our study demonstrated that short peptides present in B. subtilis culture can play an important role in the maintenance of fresh-cut pumpkin by suppressing fungal growth. © 2019 Society of Chemical Industry.


Assuntos
Bacillus subtilis/química , Cucurbita/microbiologia , Fungos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Peptídeos/farmacologia , Bacillus subtilis/metabolismo , Frutas/microbiologia , Fungos/crescimento & desenvolvimento , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Penicillium chrysogenum/efeitos dos fármacos , Penicillium chrysogenum/crescimento & desenvolvimento , Peptídeos/química , Peptídeos/metabolismo , Phytophthora/efeitos dos fármacos , Phytophthora/crescimento & desenvolvimento , Doenças das Plantas/microbiologia
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