Mode of action of N-phosphonomethylglycine. Inhibition of aromatic amino acid biosynthsis

Jaworski, Ernest G.

doi:10.1021/jf60184a057

Cited by 306 publications

(210 citation statements)

References 8 publications

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“…Other compounds which reverse glyphosate inhibition of cell growth gave a range of effects on glyphosate uptake: succinate, a-ketoglutarate, glutamate, pyruvate, and malate at 10 millimolar and phenylalanine at 2 millimolar reduced uptake by 0,8,11,16, 27, and 34%, respectively. These results suggest that more than one mechanism of reversal may operate in these cels.…”

mentioning

confidence: 99%

“…Early work (11) showed that glyphosateinduced growth inhibition of duckweed (Lemna gibba) and Rhizobium japonicum could be overcome by supplying aromatic amino acids. Similar results have been reported with Escherichia coli, Chlamydomonas reinhardii, Arabidopsis thaliana, and cultured cells of carrot (Daucus carota), soybean (Glycine max), and tobacco (Nicotiana tabacum) (6,8).…”

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confidence: 99%

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Effects of Aspartate and Other Compounds on Glyphosate Uptake and Growth Inhibition in Cultured Carrot Cells

Nafziger

Widholm²,

Slife³

1983

Plant Physiol.

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The strong correlation between glyphosate uptake and growth inhibition of cultured carrot (Daucus carota L. cv Danvers) cells incubated in the presence ofaspartate suggests that aspartate reverses glyphosate inhibition of growth primarily by reducing intracellular glyphosate concentration. Other compounds which reverse glyphosate inhibition of cell growth gave a range of effects on glyphosate uptake: succinate, a-ketoglutarate, glutamate, pyruvate, and malate at 10 millimolar and phenylalanine at 2 millimolar reduced uptake by 0,8,11,16, 27, and 34%, respectively. These results suggest that more than one mechanism of reversal may operate in these cels.Glyphosate and aspartate produced only minor effects on intracellular ammonia, media pH, and cell viability. This suggests that ammonia toxicity may not be an inportant mechanism of action of glyphosate in this system.The activity of the nonselective herbicide glyphosate [N-(phos-phonomethyl)glycinel in plants has been under investigation for more than 10 years. Early work (11) showed that glyphosateinduced growth inhibition of duckweed (Lemna gibba) and Rhizobium japonicum could be overcome by supplying aromatic amino acids. Similar results have been reported with Escherichia coli, Chlamydomonas reinhardii, Arabidopsis thaliana, and cultured cells of carrot (Daucus carota), soybean (Glycine max), and tobacco (Nicotiana tabacum) (6,8).Based on the reversal of glyphosate inhibition by aromatic amino acids, it was proposed that the herbicide may act by reducing the synthesis of these amino acids (11). Glyphosateinduced reductions in the levels of aromatic amino acids have been found in maize roots (9), soybean hypocotyls (4), wheat (16), and buckwheat hypocotyls (10). Recent work (1) has shown that the reduction in aromatic amino acid levels may result from the inhibition of an enzyme in the pathway from shikimate to the aromatic amino acids. Using a cell-free extract from Aerobacter aerogenes, the enzyme 5-enolpyruvylshikimic-3-P synthetase was identified as the specific site of glyphosate inhibition (17). Similar activity in higher plants was inferred from the accumulation of shikimate and reductions in levels of its metabolites (e.g. chorismate and anthocyanin) in cultured Galium mollugo cells and in buckwheat hypocotyls (1).In addition to the previously observed reversal of glyphosate inhibition by aromatic amino acids, it has been reported recently (12) that a variety of organic and amino acids-pyruvic, a-ketoglutaric succinic, malic, glutamic, and aspartic-reverse glyphos-'This work was carried out with funds from the Illinois Agricultural Experiment Station and National Science Foundation Grant PCM 80-10927.ate inhibition of the growth of cultured carrot cells. From work showing that organic acids can reduce ammonia toxicity in cultured cells (2), it was concluded that glyphosate may inhibit growth by causing ammonia to increase to toxic levels. Also, the tricarboxylic acid cycle indirectly feeds the shikimic acid pathway, and this cycle could be dep...

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mentioning

confidence: 99%

Effects of Aspartate and Other Compounds on Glyphosate Uptake and Growth Inhibition in Cultured Carrot Cells

Nafziger

Widholm²,

Slife³

1983

Plant Physiol.

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“…y se expusieron a los tratamientos por 72 horas a 37°C, 5% CO 2 . Al finalizar el período de incubación, se agregaron 40 µl del reactivo reconstituido XTT a cada pozo y los platos se incubaron a 37°C, en atmósfera húmeda con 5% CO 2 …”

Section: Método De Citotoxicidad In Vitro Basado En Xtt (Tox-2 Sigma)unclassified

Citotoxicidad del glifosato en células mononucleares de sangre periférica humana

Martínez

Reyes

2007

biomedica

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Introducción. El glifosato es un herbicida de amplio espectro, no selectivo, utilizado comúnmente en agricultura para eliminar malezas. Los estudios que han evaluado la toxicidad del glifosato en animales y en ambiente muestran que las formulaciones comerciales son más tóxicas que el componente activo. Objetivos. Evaluar la toxicidad del glifosato grado técnico y de la formulación comercial Roundup® en células mononucleares de sangre periférica humana. Materiales y métodos. Células mononucleares de sangre periférica humana fueron expuestas a diferentes concentraciones de glifosato en grado técnico y en la forma de Roundup® por 24, 48, 72 y 96 horas. La citotoxicidad se evaluó mediante el método de exclusión con azul de tripano y reducción del reactivo sal sódica de (2,3-bis[2-metoxi-4-nitro-5-sulfofenil]-2Htetrazolio-5-carboxianilida) (XTT). Resultados. Ambas presentaciones del glifosato (grado técnico y Roundup®) fueron tóxicas para las células mononucleares de sangre periférica humana. Roundup® fue más citotóxico que el glifosato grado técnico, ya que se encontró que la concentración letal 50 (LC 50 ) analizada con el método de exclusión con azul de tripano a las 24 horas fue de 56,4 µg/ml de glifosato en la forma de Roundup® y de 1.640 mg/ml (1,64 µg/ml) para glifosato grado técnico. Conclusiones. Los resultados de este estudio in vitro confirman el efecto tóxico para las células humanas observado para el glifosato y sus preparaciones comerciales, y que estas últimas son más citotóxicas que el compuesto activo, lo que apoya la idea de que los aditivos presentes en las formulaciones comerciales juegan un papel crucial en la toxicidad atribuida a los herbicidas que contienen glifosato.Palabras clave: pruebas inmunológicas de citotoxicidad, herbicidas, células sanguíneas, supervivencia celular, azul de tripano, sales de tetrazolio. Cytotoxicity of the herbicide glyphosate in human peripheral blood mononuclear cellsIntroduction. Glyphosate is a broad-spectrum, non-selective herbicide and commonly used to eliminate weeds in agricultural and forest settings. Studies evaluating glyphosate toxicity in animals and environment show that commercial formulations of glyphosate are more toxic than the active component itself. Objectives. Technical grade glyphosate was compared with the commercial formulation Roundup® in their respective toxicities on human peripheral blood mononuclear cells. Materials and methods. Human peripheral blood mononuclear cells were exposed to different concentrations of glyphosate, either technical grade or in the form of Roundup for 24 h, 48 h, 72 h, and 96 h. Cytotoxicity was assayed by trypan blue dye exclusion method and reduction of (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2Htetrazolium-5-carboxyanilide inner salt) XTT reagent. Results. Both technical grade glyphosate and Roundup® formulation were toxic to human peripheral blood mononuclear cells. Cytotoxicity of Roundup® was higher than cytotoxicity of glyphosate, since the LC 50 (50% lethal concentration) determined by the trypan blue ex...

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“…Pesquisas com herbicidas que agem no metabolismo de aminoácidos demonstram que o suprimento exógeno de aminoácidos pode reduzir a inibição do crescimento em plantas por eles atingidas (Jaworski, 1972;Gresshoff, 1979). Durante as décadas de 1980 e 1990, estudos visando descobrir os mecanismos de ação dos herbicidas eram feitos a partir da aplicação de determinadas moléculas em plantas e, posteriormente, incubando-as com diversas combinações de aminoácidos.…”

Section: Introductionunclassified

“…No caso dos herbicidas inibidores da enzima 5-enol-piruvil-3-shikimato-fosfato sintetase -EPSPs, um dos primeiros trabalhos conduzidos visando suprimir os efeitos do herbicida glyphosate pela adição da mistura de fenilalanina, tirosina e triptofano foi descrito por Jaworski (1972), o qual utilizou Prevenção de injúrias causadas por glyphosate em soja RR ... esses três aminoácidos para prevenir a inibição do crescimento de Lemma gibba e da bactéria Rhizobium japonicum pela aplicação do glyphosate. Esses mesmos resultados estão de acordo com os de Santos et al (2005), para os quais a adição desses aminoácidos aromáticos ao meio de cultura preveniu a inibição do crescimento de B. japonicum, uma vez que este microrganismo possui a enzima sensível ao glyphosate (Moorman et al, 1992).…”

Section: Introductionunclassified

Prevenção de injúrias causadas por glyphosate em soja RR por meio do uso de aminoácido

Zobiole

Oliveira²,

Constantin³

et al. 2011

Planta daninha

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RESUMO -A área de soja resistente ao glyphosate (RR) tem aumentado a cada ano. No entanto, essa expansão com a tecnologia da soja RR aumentou o uso de glyphosate significativamente, e muitos agricultores têm notado que alguns cultivares RR apresentam injúrias visuais logo após a aplicação do glyphosate em pós-emergência. Dessa forma, dois experimentos foram instalados em anos distintos, com diferentes objetivos: o primeiro, visando avaliar a influência do glyphosate na soja RR nas variáveis fotossintéticas e de biomassa, e o segundo, a fim de reavaliar os mesmos parâmetros afetados na soja RR pelo glyphosate, bem como o uso de diversas modalidades de aplicação de aminoácidos como forma de uma provável recuperação das plantas de soja com sua utilização exógena. A taxa fotossintética e o índice SPAD apresentaram decréscimos proporcionais às doses de glyphosate aplicadas, sendo o efeito pronunciado com a aplicação única desse herbicida. Devido ao decréscimo da taxa fotossintética, à produção de clorofila e à provável imobilização de nutrientes nos tecidos foliares causada pelo glyphosate, foi observada menor produção de biomassa. Entretanto, o uso de aminoácidos exógenos amenizou os efeitos indesejáveis desse herbicida na cultura da soja RR.Palavras-chave: fotossíntese, herbicida, clorose, Rhizobium.ABSTRACT -Glyphosate-resistant (RR) soybean crop areas have expanded every year. However, as a result of this expansion, the use of glyphosate has significantly increased, with the appearance of visual injuries in RR soybeans immediately after post-emergence application of the herbicide. Thus, two experiments were conducted in different years with different objectives. The first experiment aimed to evaluate the influence of glyphosate on photosynthetic variables and biomass production. The second experiment aimed to re-evaluate the same parameters affected in RR soybeans by glyphosate, as well as the use of various methods of amino acid application, as a form of a likely recovery of the soybean plants following these exogenous applications. The photosynthetic rate and SPAD index decreased as the glyphosate rate increased, with a pronounced decrease after a single herbicide application. Overall, due to a decrease in the photosynthetic rate and chlorophyll production, as well as to a likely immobilization of shoot nutrient concentration by glyphosate, a significant biomass decrease was verified in the treatments with glyphosate application. However, the use of exogenous amino acids may be a strategy to safeguard the undesirable effects of this herbicide on RR soybean.

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Mode of action of N-phosphonomethylglycine. Inhibition of aromatic amino acid biosynthsis

Cited by 306 publications

References 8 publications

Effects of Aspartate and Other Compounds on Glyphosate Uptake and Growth Inhibition in Cultured Carrot Cells

Effects of Aspartate and Other Compounds on Glyphosate Uptake and Growth Inhibition in Cultured Carrot Cells

Citotoxicidad del glifosato en células mononucleares de sangre periférica humana

Prevenção de injúrias causadas por glyphosate em soja RR por meio do uso de aminoácido

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