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1.
PLoS One ; 17(12): e0278717, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36454974

RESUMO

A high yield of isolated protoplast and reliable regeneration system are prerequisite for successful somatic hybridization and genome editing research. However, reproducible plant regeneration from protoplasts remains a bottleneck for many crops, including cassava. We evaluated several factors that influence isolation of viable protoplasts form leaf mesophyll, induction of embryogenic calli, and regeneration of plants in three cassava cultivars; Muchericheri, TMS60444 and Karibuni. A relatively higher protoplast yield was obtained with enzyme mixture containing 5 g/L Macerozyme and 10 g/L cellulase. Muchericheri recorded relatively higher protoplast yield of 20.50±0.50×106 whereas TMS60444 (10.25±0.25×106) had the least protoplast yield in 10 g/L cellulase and 4 g/L cellulase. Freshly isolated protoplast cells were plated on callus induction medium (CIM) solid medium containing MS basal salt, 60 g/L D-glucose, 30 g/L sucrose, B5 vitamins, 100 mg/L myo-inositol, 0.5 mg/L copper sulphate, 100 mg/L casein hydrolysate, 4.55 g/L mannitol, 0.1 g/L MES, 10 mg/L picloram and 3 g/L gelrite to induce protoplast growth and development. The three cultivars reached colony formation but no further development was observed in this culture method. Protoplast growth and development was further evaluated in suspension culture using varying cell densities (1, 2 and 3× 105 p/mL). Development with highest number of minicalli was observed in cell density of 3× 105 p/mL. Minicalli obtained were cultured on CIM supplemented with 10mg/L picloram. Callus induction was observed in all cell densities with the cultivars. Highest somatic embryogenesis was observed in 2× 105 p/ml while no somatic embryogenesis was observed in cell density of 1×105 p/mL. Somatic embryos were matured in EMM medium supplemented with 1 mg/L BAP, 0.02 mg/L NAA and 1.5 mg/L GA3 then germinated in hormone free medium for plant regeneration. This protocol which used simple mixture of commercial enzymes is highly reproducible and can be applied in biotechnology research on cassava.


Assuntos
Calosidades , Celulase , Manihot , Protoplastos , Picloram , Verduras , Folhas de Planta , Regeneração
2.
Mol Biol Rep ; 49(12): 11273-11280, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35804213

RESUMO

BACKGROUND: Many genotoxicity tests allow us to understand the mechanism of damages on genetic material occurring in living organisms against various physical and chemical agents. One of them is the Comet test. The current study aimed to evaluate genotoxic caused by picloram and dicamba to root meristems of Allium cepa utilizing comet assay. METHODS: Two different protocols were used for rooting and auxin/pesticide application. (i) A. cepa bulbs were rooted in MS medium and then treated with Murashige and Skoog (MS) medium (control) and 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of picloram and dicamba using aseptic tissue culture techniques. (ii) A. cepa bulbs were then rooted in bidistilled water and treated with 0 (control), 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of picloram and dicamba in distilled water. The A. cepa root tip cells in both treatment groups were examined using comet test to find the possible DNA damaging effects of picloram and dicamba. RESULTS: The results obtained at all the concentrations were statistically compared with their control groups. Almost at all the concentrations of Picloram and dicamba increased comet tail intensity (%) and tail moment in roots treated in MS medium. Two highest concentrations revealed toxic effect. On the other hand, DNA damaging effect of both auxins was only noted on the highest (> 4.02 mg/L) in roots treated in distilled water. CONCLUSIONS: This study approve and confirm genotoxic effects of how growth regulators on plants. These findings give an evidence of DNA damage in A. cepa. Therefore, both picloram and dicamba should only be used in appropriate and recommended concentrations in agriculture to conserve ecosystem and to pose minimum threat to life.


Assuntos
Dicamba , Cebolas , Ensaio Cometa , Cebolas/genética , Dicamba/farmacologia , Picloram/farmacologia , Ecossistema , Aberrações Cromossômicas/induzido quimicamente , Dano ao DNA , Água
3.
Environ Monit Assess ; 194(7): 474, 2022 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-35657507

RESUMO

The pesticides used have contributed to increasing food production; it has also caused them to be found in most ecosystems and have negative effects on biota. The neotropical otter (Lontra longicaudis) is vulnerable to pesticide accumulation and is characterized by being elusive, so it is necessary to address the use of indirect techniques that evaluate its populations' state in an efficient, logistically simple, and non-invasive way. This study aimed to determine the concentration of 20 pesticides in neotropical otter feces in the Ayuquila-Armería basin and to describe the spatiotemporal variation of these pesticides. The presence of 11 pesticides was determined. Imazalil, picloram, and malathion the pesticides with the highest concentrations; emamectin, λ-cyhalothrin, methomyl, and picloram were present in all samples. Emamectin was the only pesticide that presented significant differences concerning the temporality of the samplings, presenting higher concentrations in the wet season. Molinate concentrations showed significant differences concerning the location of the sampling sections in the basin; the lower part of the basin presented higher concentrations. The distribution of the populations of L. longicaudis in the Ayuquila-Armería basin does not respond to the degree of contamination by pesticides in surface waters or to the proximity to agricultural activities, and this in places with evident chemical and organic contamination and human presence. The use of otter feces for pesticide monitoring is an accepted non-invasive method to assess the degree of exposure and can be used to determine sites with pollution problems.


Assuntos
Lontras , Praguicidas , Poluentes Químicos da Água , Animais , Ecossistema , Monitoramento Ambiental , Fezes/química , Humanos , México , Praguicidas/análise , Picloram/análise , Poluentes Químicos da Água/análise
4.
Int J Phytoremediation ; 24(9): 987-994, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34665679

RESUMO

Hormone-like herbicides, used for large crops, can contaminate non-target areas with their waste. The objective of this study was to evaluate the tolerance of Mabea fistulifera and Zeyheria tuberculosa to 2,4-D + picloram herbicides by means of morphological and anatomical evaluations. The experiment was performed in a greenhouse in a 4 × 2 factorial scheme. The first factor was the control (without herbicide) and three doses (0.166; 0.333, and 0.666 L ha-1) of the herbicide Tordon® (402 g L-1 2,4-D + 103.6 g L-1 picloram) and the second factor, the species Mabea fistulifera and Zeyheria tuberculosa. The number of M. fistulifera leaves was lower after treatment with the highest dose of the 2,4-D + picloram mixture. The herbicide rates did not influence the number of Z. tuberculosa leaves. The higher dose of 2,4-D + picloram caused a more than 50% reduction in leaf area. Toxicity increased linearly as a function of the doses of the 2,4-D + picloram mixture. Changes in the leaf anatomy of the two species treated with herbicides were observed; however, the roots did not show any changes. Mabea fistulifera and Zeyheria tuberculosa can be recommended for phytoremediation programs in areas contaminated by the herbicides 2,4-D + picloram.


Phytoremediation of soils contaminated with herbicides is a recent and viable tool for environmental decontamination and for the protection of water resources. Mabea fistulifera and Zeyheria tuberculosa can be used to compose riparian forests and retain the arrival of herbicides in the water. Plant anatomy and morphological characteristics are viable tools to assess the tolerance and phytoremediation potential of plant species. Mabea fistulifera and Zeyheria tuberculosa are tolerant to the presence of hormonal herbicides. In this way, they can be used to recover natural areas close to the cultivation areas where the herbicides 2,4-D and picloram are used.


Assuntos
Herbicidas , Picloram , Ácido 2,4-Diclorofenoxiacético , Biodegradação Ambiental , Solo
5.
Biomolecules ; 11(8)2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34439819

RESUMO

With the introduction of the new auxinic herbicide halauxifen-methyl into the oilseed rape (Brassica napus) market, there is a need to understand how this new molecule interacts with indigenous plant hormones (e.g., IAA) in terms of crop response. The aim of this study was to investigate the molecular background by using different growth conditions under which three different auxinic herbicides were administered. These were halauxifen-methyl (Hal), alone and together with aminopyralid (AP) as well as picloram (Pic). Three different hormone classes were determined, free and conjugated indole-3-acetic acid (IAA), aminocyclopropane carboxylic acid (ACC) as a precursor for ethylene, and abscisic acid (ABA) at two different temperatures and growth stages as well as over time (2-168 h after treatment). At 15 °C growth temperature, the effect was more pronounced than at 9 °C, and generally, the younger leaves independent of the developmental stage showed a larger effect on the alterations of hormones. IAA and ACC showed reproducible alterations after auxinic herbicide treatments over time, while ABA did not. Finally, a transcriptome analysis after treatment with two auxinic herbicides, Hal and Pic, showed different expression patterns. Hal treatment leads to the upregulation of auxin and hormone responses at 48 h and 96 h. Pic treatment induced the hormone/auxin response already after 2 h, and this continued for the other time points. The more detailed analysis of the auxin response in the datasets indicate a role for GH3 genes and genes encoding auxin efflux proteins. The upregulation of the GH3 genes correlates with the increase in conjugated IAA at the same time points and treatments. Also, genes for were found that confirm the upregulation of the ethylene pathway.


Assuntos
Ácido Abscísico/farmacologia , Aminoácidos Cíclicos/farmacologia , Brassica napus/efeitos dos fármacos , Herbicidas/farmacologia , Ácidos Indolacéticos/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Ácido Abscísico/metabolismo , Aminoácidos Cíclicos/metabolismo , Brassica napus/genética , Brassica napus/metabolismo , Ácidos Carboxílicos/farmacologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Ácidos Indolacéticos/metabolismo , Anotação de Sequência Molecular , Picloram/farmacologia , Reguladores de Crescimento de Plantas/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Piridinas/farmacologia , Temperatura , Transcriptoma
6.
Molecules ; 26(11)2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34072168

RESUMO

This study aims to investigate whether the in vitro-cultured L. pumila var. alata has higher antioxidant activity than its wild plant. An 8-week-old L. pumila var. alata nodal segment and leaf explants were cultured onto Murashige and Skoog (MS) medium supplemented with various cytokinins (zeatin, kinetin, and 6-benzylaminopurine (BAP)) for shoot multiplication and auxins (2,4-dichlorophenoxyacetic acid (2,4-D) and picloram) for callus induction, respectively. The results showed that 2 mg/L zeatin produced the optimal results for shoot and leaf development, and 0.5 mg/L 2,4-D produced the highest callus induction results (60%). After this, 0.5 mg/L 2,4-D was combined with 0.25 mg/L cytokinins and supplemented to the MS medium. The optimal results for callus induction (100%) with yellowish to greenish and compact texture were obtained using 0.5 mg/L 2,4-D combined with 0.25 mg/L zeatin. Leaves obtained from in vitro plantlets and wild plants as well as callus were extracted and analyzed for their antioxidant activities (DPPH and FRAP methods) and polyphenolic properties (total flavonoid and total phenolic content). When compared with leaf extracts of in vitro plantlets and wild plants of L. pumila var. alata, the callus extract displayed significantly higher antioxidant activities and total phenolic and flavonoid content. Hence, callus culture potentially can be adapted for antioxidant and polyphenolic production to satisfy pharmaceutical and nutraceutical needs while conserving wild L. pumila var. alata.


Assuntos
Calo Ósseo/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Brotos de Planta/efeitos dos fármacos , Polifenóis/química , Primulaceae/efeitos dos fármacos , Ácido 2,4-Diclorofenoxiacético/química , Antioxidantes/química , Compostos de Benzil/química , Compostos de Bifenilo/química , Meios de Cultura , Suplementos Nutricionais , Flavonoides/química , Técnicas In Vitro , Cinetina/química , Fenol/química , Picloram/química , Picratos/química , Folhas de Planta , Proteínas de Plantas , Raízes de Plantas/efeitos dos fármacos , Plantas/efeitos dos fármacos , Purinas/química , Zeatina/química
7.
Chemosphere ; 278: 130401, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33839382

RESUMO

Pesticides are chemical compounds widely used to combat pests in crops, and they thus play a key role in agricultural production. However, due to their persistence in aquatic environments, even at low concentrations, their use has been considered an environmental problem and caused concern regarding the adverse effects on human health. This paper reports, for the first time, the mechanisms, kinetics, and an evaluation of the toxicity of picloram degradation initiated by OH radicals in the aqueous environment using quantum chemistry and computational toxicology calculations. The rate constants are calculated using a combination of formulations derived from the Transition State Theory in a realistic temperature range (250-310 K). The results indicate that the two favorable pathways (R1 and R5) of OH -based reactions occur by addition to the pyridine ring. The calculated rate constant at 298 K is compared with the overall second-order reaction rate constant, quantified herein experimentally via the competition kinetics method and data available in the literature showing an excellent agreement. The toxicity assessment and a photolysis study provide important information: i) picloram and the majority of degradation products are estimated as harmful; however, ii) these compounds can suffer photolysis in sunlight. The results of the present study can help understand the mechanism of picloram, also providing important clues regarding risk assessment in aquatic environments as well as novel experimental information.


Assuntos
Radical Hidroxila , Poluentes Químicos da Água , Humanos , Cinética , Oxirredução , Picloram , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
8.
Plant J ; 106(6): 1523-1540, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33768644

RESUMO

Temperature passively affects biological processes involved in plant growth. Therefore, it is challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf-cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2-deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound 'Heatin', containing 1-iminomethyl-2-naphthol as a pharmacophore, was selected as an enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members, NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and the application of Heatin accordingly results in the accumulation of NIT1-subfamily substrate indole-3-acetonitrile in vivo. However, levels of the NIT1-subfamily product, bioactive auxin (indole-3-acetic acid), were also significantly increased. It is likely that the stimulation of hypocotyl elongation by Heatin might be independent of its observed interaction with NITRILASE1-subfamily members. However, nitrilases may contribute to the Heatin response by stimulating indole-3-acetic acid biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology.


Assuntos
Aminoidrolases/metabolismo , Arabidopsis/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Hipocótilo/efeitos dos fármacos , Aldeído Oxidase/genética , Aldeído Oxidase/metabolismo , Aminoidrolases/genética , Apomorfina/análogos & derivados , Apomorfina/farmacologia , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Herbicidas/farmacologia , Hipocótilo/crescimento & desenvolvimento , Ácidos Indolacéticos , Estrutura Molecular , Picloram/farmacologia , Relação Estrutura-Atividade , Transcriptoma/efeitos dos fármacos
9.
An Acad Bras Cienc ; 93(1): e20181262, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33787683

RESUMO

Due to rising concerns for environmental and human health, many toxic compounds, such as auxin-based herbicides, have been tested in relation their toxicity effect. Especially cyto- and phytotoxic assays have been performed on a number monocot and eudicot plant species. In these approaches the toxicity level of the auxin is compared to a positive control - usually a commercial compound with known effects and chemical similarity to the target compound. However, many target compounds still lack an indication of an adequate positive control. Here, we evaluate the phytotoxic and cytotoxic effect of the auxins 2,4-dichlorophenoxyacetic acid, dicamba, and picloram in order test their potential use as positive controls. All tested auxinic herbicides showed clastogenic and aneugenic effect mechanisms. The results indicate 2,4-dichlorophenoxyacetic acid as the most phyto- and cytotoxic in the discontinuous method in Lactuca sativa L. and Allium cepa L., and also in the continuous method in A. cepa. Thus, we suggest 2,4-dichlorophenoxyacetic acid as a positive control for future mutagenesis studies involving new auxins. For studies with L. sativa in continuous method, we recommend the auxin picloram as positive control as this one was the only one which allowed the development of roots.


Assuntos
Herbicidas , Dicamba/toxicidade , Herbicidas/toxicidade , Humanos , Ácidos Indolacéticos , Picloram , Raízes de Plantas
10.
An Acad Bras Cienc ; 92(3): e20180709, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33206795

RESUMO

A somatic embryogenesis protocol was developed from the immature leaves of adult plants of the macaw palm. Leaf explants from different regions of the palm heart were used for callus initiation in a modified Y3 medium, supplemented with 2,4-D or Picloram at 450 µM. Calli were separated from the leaf explants at 6-, 9- and 12-month periods and transferred to a fresh culture medium of the same composition. They were multiplied for up to 120 days. Reduced concentrations of 2,4-D and Picloram were used to differentiate somatic embryos. They were then germinated in a medium without plant growth regulators. Morphological and anatomical analyses were conducted at different stages of the embryogenic process. The best results for callus induction were achieved by Picloram, when explants were maintained for up to 9 months on culture medium (64.9%). The farthest portions of the apical meristem were those that provided the biggest calli formation. The formation of the somatic embryos was observed from the calli multiplication phase. Reduction in concentrations of growth regulators failed to promote the formation of complete plants. Picloram at 450 µM promotes high callogenesis in leaf tissues of macaw palm, with a potential for somatic embryo formation.


Assuntos
Arecaceae , Desenvolvimento Embrionário , Picloram , Reguladores de Crescimento de Plantas , Folhas de Planta , Técnicas de Embriogênese Somática de Plantas
11.
Int J Mol Sci ; 21(9)2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32403374

RESUMO

The effects of auxins 2,4-D (2,4-dichlorophenoxyacetic acid), NAA (1-naphthaleneacetic acid) or picloram (4-amino-3,5,6-trichloropicolinic acid; 9 µM) and cytokinin BA (benzyloadenine; 4.5 µM) applied in the early stages of somatic embryogenesis (SE) on specific stages of SE in Picea abies and P. omorika were investigated. The highest SE initiation frequency was obtained after 2,4-D application in P. omorika (22.00%) and picloram application in P. abies (10.48%). NAA treatment significantly promoted embryogenic tissue (ET) proliferation in P. abies, while 2,4-D treatment reduced it. This reduction was related to the oxidative stress level, which was lower with the presence of NAA in the proliferation medium and higher with the presence of 2,4-D. The reduced oxidative stress level after NAA treatment suggests that hydrogen peroxide (H2O2) acts as a signalling molecule and promotes ET proliferation. NAA and picloram in the proliferation medium decreased the further production and maturation of P. omorika somatic embryos compared with that under 2,4-D. The quality of the germinated P. abies embryos and their development into plantlets depended on the auxin type and were the highest in NAA-originated embryos. These results show that different auxin types can generate different physiological responses in plant materials during SE in both spruce species.


Assuntos
Ácidos Indolacéticos/farmacologia , Picea/efeitos dos fármacos , Técnicas de Embriogênese Somática de Plantas/métodos , Sementes/efeitos dos fármacos , Ácido 2,4-Diclorofenoxiacético/farmacologia , Células Cultivadas , Citocininas/farmacologia , Peróxido de Hidrogênio/metabolismo , Ácidos Indolacéticos/classificação , Morfogênese/efeitos dos fármacos , Ácidos Naftalenoacéticos/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Picea/classificação , Picea/embriologia , Picloram/farmacologia , Reguladores de Crescimento de Plantas/classificação , Reguladores de Crescimento de Plantas/farmacologia , Sementes/citologia , Sementes/embriologia , Especificidade da Espécie
12.
Plant Physiol ; 182(2): 892-907, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31767691

RESUMO

Auxin plays a central role in controlling plant cell growth and morphogenesis. Application of auxin to light-grown seedlings elicits both axial growth and transverse patterning of the cortical microtubule cytoskeleton in hypocotyl cells. Microtubules respond to exogenous auxin within 5 min, although repatterning of the array does not initiate until 30 min after application and is complete by 2 h. To examine the requirements for auxin-induced microtubule array patterning, we used an Arabidopsis (Arabidopsis thaliana) double auxin f-box (afb) receptor mutant, afb4-8 afb5-5, that responds to conventional auxin (indole-3-acetic acid) but has a strongly diminished response to the auxin analog, picloram. We show that 5 µm picloram induces immediate changes to microtubule density and later transverse microtubule patterning in wild-type plants, but does not cause microtubule array reorganization in the afb4-8 afb5-5 mutant. Additionally, a dominant mutant (axr2-1) for the auxin coreceptor AUXIN RESPONSIVE2 (AXR2) was strongly suppressed for auxin-induced microtubule array reorganization, providing additional evidence that auxin functions through a transcriptional pathway for transverse patterning. We observed that brassinosteroid application mimicked the auxin response, showing both early and late microtubule array effects, and induced transverse patterning in the axr2-1 mutant. Application of auxin to the brassinosteroid synthesis mutant, diminuto1, induced transverse array patterning but did not produce significant axial growth. Thus, exogenous auxin induces transverse microtubule patterning through the TRANSPORT INHIBITOR 1/AUXIN F-BOX (TIR1/AFB) transcriptional pathway and can act independently of brassinosteroids.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ácidos Indolacéticos/metabolismo , Microtúbulos/efeitos dos fármacos , Receptores de Superfície Celular/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Brassinosteroides/farmacologia , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas F-Box/genética , Proteínas F-Box/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Hipocótilo/efeitos dos fármacos , Hipocótilo/crescimento & desenvolvimento , Ácidos Indolacéticos/farmacologia , Microtúbulos/genética , Microtúbulos/metabolismo , Mutação , Picloram/farmacologia , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Plantas Geneticamente Modificadas , Receptores de Superfície Celular/genética , Plântula/efeitos dos fármacos , Plântula/metabolismo , Transdução de Sinais/efeitos dos fármacos
13.
Colloids Surf B Biointerfaces ; 181: 953-958, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31382345

RESUMO

Cell membrane models are useful to obtain molecular-level information on the interaction of biologically-relevant molecules such as pesticides whose activity is believed to depend on its effects on the membrane. In this study, we investigated the interaction between the widely used pesticide picloram with Langmuir monolayers of binary and ternary mixtures comprising 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), sphingomyelin (SM) and cholesterol (Chol), which could be taken as representative of ocular membranes in humans. Picloram expanded the molecular area of DOPC/SM and DOPC/SM/Chol monolayers as the pesticide penetrated the hydrophobic region of the mixtures. A clear correlation was also found between the compressibility modulus (Cs-1) and the presence of cholesterol in the ternary monolayer. Data from polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) confirmed that picloram interacts with both the acyl chains and headgroups. Spectral shifts and band broadening were induced by picloram, particularly for the phosphate and choline groups, probably owing to its H-bonding ability. The effects reported here on the lipid monolayers may be evidence of the possible activity of picloram on mammalian cell membranes, which highlights the importance of strict control of the level of exposure of humans dealing with pesticides.


Assuntos
1,2-Dipalmitoilfosfatidilcolina/química , Colesterol/química , Praguicidas/farmacologia , Picloram/farmacologia , Esfingomielinas/química , Membrana Celular/efeitos dos fármacos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Praguicidas/química , Picloram/química , Propriedades de Superfície
14.
Toxicol Lett ; 313: 137-149, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31254607

RESUMO

Tordon® is the commercial name of a mixture of two organo-chlorinated herbicides, 2,4-D and picloram. Both compounds affect energy transduction in isolated mitochondria and the present study aimed at characterizing the actions of these two compounds on liver metabolism and their cellular distribution in the isolated perfused rat liver. 2,4-D, but not picloram, increased glycolysis in the range from 10 to 400 µM. The redox potential of the cytosolic NAD+-NADH couple was also increased by 2,4-D. Both compounds inhibited lactate gluconeogenesis. Inhibitions by 2,4-D and picloram were incomplete, reaching maximally 46% and 23%, respectively. Both compounds diminished the cellular ATP levels. No synergism between the actions of 2,4-D and picloram was detected. Biotransformations of 2,4-D and picloram were slow, but their distributions occurred at high rates and were concentrative. Molecular dynamics simulations revealed that 2,4-D presented low affinity for the hydrophobic lipid bilayers, the opposite occurring with picloram. Inhibition of energy metabolism is possibly a relevant component of the toxicity of 2,4-D and of the commercial product Tordon®. Furthermore, the interactions of 2,4-D with the membrane lipid bilayer can be highly destructive and might equally be related to its cellular toxicity at high concentrations.


Assuntos
Ácido 2,4-Diclorofenoxiacético/toxicidade , Membrana Celular/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Herbicidas/toxicidade , Bicamadas Lipídicas/metabolismo , Fígado/efeitos dos fármacos , Picloram/toxicidade , Ácido 2,4-Diclorofenoxiacético/metabolismo , Animais , Membrana Celular/metabolismo , Membrana Celular/patologia , Gluconeogênese/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Herbicidas/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Cinética , Fígado/metabolismo , Fígado/patologia , Masculino , Simulação de Dinâmica Molecular , NAD/metabolismo , Oxirredução , Perfusão , Picloram/metabolismo , Ratos Wistar
15.
Biophys Chem ; 250: 106176, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31055199

RESUMO

Giant unilamellar vesicles (GUVs) have been one of the most extensively investigated membrane model to study cell membrane-ligand interactions. In this study, we investigated the interaction between glyphosate and picloram with GUVs made with sphingomyelin (SM), cholesterol (CHOL), and dioleoyl-sn-glycerol-3-phosphocholine (DOPC) (DOPC/SM (1:1), DOPC/CHOL/SM (1:1:1)) in a physiological environment using confocal and phase contrast microscopy. At high pesticide concentrations (70 to 90 µM), we generally found the GUVs undergoing a physical such as contouring, elongation, and eventually lose their characteristic spherical shape. In addition, to determine the comparative effect of the pesticides, control experiments were performed using GUVs made with only DOPC and DOPC/SM 1:1. The results show that, at low concentration (0.5 µM), a significant effect was observed during a 30 min incubation time. These findings also suggest that cholesterol may play a significant role in the permeability of the vesicle against the action of the pesticides, which have important biological implications on the lipid composition of the membrane.


Assuntos
Membrana Celular/química , Colesterol/química , Glicina/análogos & derivados , Picloram/química , Lipossomas Unilamelares/química , Glicina/química , Ligantes , Tamanho da Partícula , Fosfatidilcolinas/química , Esfingomielinas/química , Propriedades de Superfície
16.
J Environ Sci Health B ; 54(4): 281-289, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30755089

RESUMO

The picloram (PCM) adsorption on nontronite, illite and kaolinite was studied at pH 3, 5 and 7. The adsorption isotherms had well-fitted to Langmuir and Freundlich models equations. The interactions of PCM with the clay mineral surfaces exhibited an anionic profile adsorption, with a decrease in adsorption when the pH increases. The PCM adsorption capacity increases in the following order: kaolinite < illite < nontronite. The X-ray diffraction (XRD) analysis of PCM-clay samples revealed that the picloram molecule does not enter into the clays basal space. The interaction of PCM with clays surface sites through nitrogen of the pyridine ring was confirmed by X-ray photoelectron spectroscopy (XPS). Due to the anionic form of PCM, the adsorption onto the external and edges surface sites of the clay minerals was proposed.


Assuntos
Argila/química , Caulim/química , Minerais/química , Picloram/isolamento & purificação , Adsorção , Herbicidas/química , Herbicidas/isolamento & purificação , Concentração de Íons de Hidrogênio , Espectroscopia Fotoeletrônica , Picloram/química , Difração de Raios X
17.
J Nanobiotechnology ; 16(1): 94, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30463582

RESUMO

BACKGROUND: Modern agricultural practises rely on surfactant-based spray applications to eliminate weeds in crops. The wide spread and indiscriminate use of surfactants may result in a number of deleterious effects that are not limited to impacts on the crop and surrounding farm eco-system but include effects on human health. To provide a safer alternative to the use of surfactant-based formulations, we have synthesised a novel, self-assembling herbicide conjugate for the delivery of a broad leaf herbicide, picloram. RESULTS: The synthesized self-assembling amphiphile-picloram (SAP) conjugate has three extending arms: a lipophilic lauryl chain, a hydrophilic polyethylene glycol chain and the amphiphobic agrochemical active picloram. We propose that the SAP conjugate maintains its colloidal stability by quickly transitioning between micellar and inverse micellar phases in hydrophilic and lipophilic environments respectively. The SAP conjugate provides the advantage of a phase structure that enables enhanced interaction with the hydrophobic epicuticular wax surface of the leaf. We have investigated the herbicidal efficiency of the SAP conjugate compared against that of commercial picloram formulations using the model plant Arabidopsis thaliana and found that when tested at agriculturally relevant doses between 0.58 and 11.70 mM a dose-dependent herbicidal effect with comparable kill rates was evident. CONCLUSION: Though self-assembling drug carriers are not new to the pharmaceutical industry their use for the delivery of agrochemicals shows great promise but is largely unexplored. We have shown that SAP may be used as an alternative to current surfactant-based agrochemical formulations and has the potential to shift present practises towards a more sustainable approach.


Assuntos
Agroquímicos/química , Portadores de Fármacos/química , Herbicidas/química , Picloram/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Micelas , Tamanho da Partícula , Folhas de Planta/metabolismo , Plantas Daninhas/metabolismo , Polietilenoglicóis/química , Tensoativos/química
18.
Environ Sci Pollut Res Int ; 25(24): 23986-23991, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29948674

RESUMO

Herbicides with long residual period may increase the risk of environmental contamination. Adequate management of forage can reduce the half-life of the picloram, one of the most herbicides used in weed control. This study aims to determine the half-life of picloram, using high-performance liquid chromatography in a cultivated soil with Brachiaria brizantha trimmed or not. Brachiaria brizantha was cultivated in 60 pots filled with samples of oxisol, and 30 others were kept uncultivated with this forage. This plant was cut off close to the ground, after 60 days of emergency on 30 vessels. Picloram was applied in all of the plots. Soil samples were collected at 2, 16, 30, 44, 58, 72, 86, 120, 150, and 180 days after the application of this herbicide. These samples were air-dried and stored at - 20 °C. Picloram was extracted by HPLC/UV-Vis detector. Half-life of this herbicide was calculated using kinetics models. The mere presence of roots in treatment with signalgrass cutoff did not reduce the concentrations of this herbicide, except when the emergence of new leaves occurred. The absence of B. brizantha cultivation in areas with application of picloram increases the risk of environmental contamination and successive crops due to the half-life of this herbicide. Brachiaria brizantha reduced half-life picloram and environmental risk in pastures. The validation method is suitable for determining picloram in low concentrations in soil.


Assuntos
Biodegradação Ambiental , Brachiaria , Herbicidas/metabolismo , Picloram/metabolismo , Poluentes do Solo/química , Cromatografia Líquida de Alta Pressão , Meia-Vida , Herbicidas/química , Picloram/química , Raízes de Plantas , Solo/química , Poluentes do Solo/análise
19.
An Acad Bras Cienc ; 90(2): 1717-1732, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29694496

RESUMO

The aim of this work was to determine the persistence of auxinic herbicides applied on tropical pasture and toxicity for succeeding crops. The herbicides were applied in an area of dystrophic red‒yellow latosol with pasture infested of weeds. At 40, 80, and 280 days after application of herbicide, the soil samples were collected at depths of 0 to 20 cm. Soil with residues of 2,4-D, 2,4-D + picloram, triclopyr, and a soil without herbicide application were analyzed with six replicates. Seven crops were cultivated in these soils: cucumber (Cucumis sativus L.), velvet bean [Mucuna pruriens (L.) DC.], pigeon pea [Cajanus cajan (L.) Millsp.], alfalfa (Medicago sativa L.), lablab bean [Lablab purpureus (L.) Sweet], corn (Zea mays L.), and sorghum [Sorghum bicolor (L.) Moench]. The plants of cucumber, pigeon pea, and alfalfa were the most susceptible to the auxinic herbicide residues. However, the lablab bean was the only one among the dicot evaluated that showed tolerance to the 2,4-D + picloram residual when cultivated in soils at 280 days after application of herbicide. Corn and sorghum showed lower chlorophyll content in soils with 2,4-D + picloram residual up to 80 days after application of herbicide.


Assuntos
Produtos Agrícolas/efeitos dos fármacos , Herbicidas/toxicidade , Ácidos Indolacéticos/toxicidade , Resíduos de Praguicidas/toxicidade , Ácido 2,4-Diclorofenoxiacético/toxicidade , Cucumis sativus/efeitos dos fármacos , Fabaceae/efeitos dos fármacos , Glicolatos/toxicidade , Medicago sativa/efeitos dos fármacos , Picloram/toxicidade , Solo/química , Sorghum/efeitos dos fármacos , Zea mays/efeitos dos fármacos
20.
Sci Total Environ ; 616-617: 128-134, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29112836

RESUMO

As a widely used herbicide, picloram has been frequently detected in the aquatic environment due to its high leaching potential and low adsorption by soil. To reduce aquatic environmental risk of this herbicide caused by leaching and runoff, five herbicidal ionic liquids (HILs) based on picloram were prepared by pairing isopropylamine, octylamine, octadecylamine, 1-methylimidazole, 4-methylmorpholine respectively. Their physicochemical properties including water solubility, octanol-water partition coefficient, surface activity, leaching, as well as soil adsorption were compared. The results showed that these properties could be adjusted by appropriate selection of counter cations. The HILs with long alkyl chains in cations had low water solubility and leaching characteristics, good surface tension and lipophilicity, as well as high soil adsorption. Compared with currently used picloram in the forms of potassium salts, HIL3 had more excellent herbicidal activity against broadleaf weeds and may offer a lower use dosage. The HILs based on picloram can reduce its negative effects on the aquatic environment and can be used as a desirable alternative to commercial herbicidal formulations of picloram in future.


Assuntos
Herbicidas/química , Líquidos Iônicos/química , Picloram/química , Poluição Ambiental/prevenção & controle , Imidazóis , Morfolinas
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