Search results for "herbicide"
showing 10 items of 273 documents
Indirect analysis of urea herbicides from environmental water using solid-phase microextraction.
2000
We described here a solid-phase microextraction procedure used to extract six urea pesticides-- chlorsulfuron, fluometuron, isoproturon, linuron, metobromuron and monuron--from environmental samples. Two polydimethylsiloxanes and a polyacrylate fiber (PA) are compared. The extraction time, pH control, addition of NaCl to the water and the influence of organic matter such as humic acid on extraction efficiency were examined to achieve a sensitive method. Determination was carried out by gas chromatography with nitrogen-phosphorus detection. The proposed method requires the extraction of 2 ml of sample (pH 4, 14.3%, w/v, NaCl) for 60 min with the PA fiber. The limits of detection range from 0…
Mode of action of herbicidal derivatives of aminomethylenebisphosphonic acid. Part II. Reversal of herbicidal action by aromatic amino acids
1997
The herbicidal action of N-pyridylaminomethylenebisphosphonic acids is accompanied by an impairment of anthocyanin biosynthesis. This suggests that they might act as inhibitors of some steps in aromatic amino acid biosynthesis. Herbicidal effects were reversed by aromatic amino acids using both bacterial and plant models, a finding that strongly supports this hypothesis. Structural features of these compounds suggest the sixth enzyme in the shikimate pathway 5-enol-pyruvoylshikimate-3-phosphate (EPSP) synthase as a possible target, since a strong structural similarity exists between aminomethylenebisphosphonic acid and an inhibitor of EPSP synthase, the herbicide glyphosate. This is, howeve…
Organophosphonate utilization by the wild‐type strain of cladosporium resinae
1997
We studied the biodegradation of compounds containing phosphorus‐to‐carbon bond by using wild‐type strain of Cladosporium resinae. The substrate specificity of the strain was studied and we found that it is able to utilize a range of structurally diverse organophosphonates as a sole source of phosphorus. This ability is inducible as indicated by the presence of a lag phase of the growth. A popular herbicide glyphosate is also degraded by the fungi. This indicates that Cladosporium resinae may play an important role in biodegradation of this herbicide. The strain which we used, however, did not metabolise any phosphonates when they served as the sole carbon or nitrogen sources.
DIAGSOL : Développement d’un outil microbien pour évaluer l’exposition des sols agricoles aux herbicides β-tricétones
2018
International audience; En 2011, en France, plus de 2 millions d’hectares de champs de maïs ont été traités avec desherbicides β-tricétones. Qualifiés de « respectueux de l’environnement » en raison d’une efficacité àfaible dose, de récentes études ont démontré un effet transitoire des β-tricétones sur la diversitébactérienne des sols (Romdhane et al., 2016). L’utilisation récurrente des β-tricétones pourrait, àterme, perturber la diversité bactérienne et les fonctions écosystémiques des sols qu’elle soutient.Il est essentiel d’évaluer l’exposition des microorganismes des sols aux β-tricétones.L’enzyme 4-hydroxyphénylpyruvate dioxygénase (4-HPPD), cible de ces herbicides chez les plantesadv…
Étude de l’évolution du potentiel génétique de populations bactériennes dégradant l’atrazine
2011
17 pages de références bibliographiques et 20 pages d'annexes; L’atrazine, un des herbicides les plus utilisés pour contrôler le développement des plantes adventices dans les cultures, a conduit à la contamination de l’environnement. L’exposition chronique à cet herbicide a conduit à l’émergence de populations microbiennes du sol capables de dégrader l’atrazine et de l’utiliser comme une source d’azote pour leur croissance. Ces populations microbiennes sont responsables de la biodégradation accélérée (BDA) de l’atrazine, un service écosystémique contribuant à diminuer la persistance de cet herbicide dans l’environnement. L’objectif de ce travail était d’étudier les mécanismes génétiques et …
Role of glutathione in Thiobencarb resistance in the European eel Anguilla anguilla.
2000
Glutathione-dependent defense against xenobiotic toxicity is a multifaceted phenomenon that has been well characterized in mammals. In the present study, eels of species Anguilla anguilla were exposed to 15 ppm of the herbicide thiobencarb (S-4-chlorobenzyl diethylthiocarbamate) for 96 h. Eels exposed to the pesticide were grouped in 24-h intervals according to their time of death, while surviving intoxicated eels constituted another group (live animals). Glutathione content (GSx, GSH, GSSG) was determined in liver and muscle tissues of the dead and live (intoxicated) animals and compared to control values (nonexposed eels). The fish that died before 96 h of exposure were considered suscept…
Glyphosate-based herbicide use affects individual microbial taxa in strawberry endosphere but not the microbial community composition
2023
AbstractAimsIn a field study, the effects of treatments of glyphosate-based herbicides (GBHs) in soil, alone and in combination with phosphate fertilizer, were examined on the performance and endophytic microbiota of garden strawberry.Methods and resultsThe root and leaf endophytic microbiota of garden strawberries grown in GBH-treated and untreated soil, with and without phosphate fertilizer, were analyzed. Next, bioinformatics analysis on the type of 5-enolpyruvylshikimate-3-phosphate synthase enzyme was conducted to assess the potential sensitivity of strawberry-associated bacteria and fungi to glyphosate, and to compare the results with field observations. GBH treatments altered the abu…
In vitro evolution of an atrazine-degrading population under cyanuric acid selection pressure: Evidence for the selective loss of a 47kb region on th…
2011
International audience; The adaptation of microorganisms to pesticide biodegradation relies on the recruitment of catabolic genes by horizontal gene transfer and homologous recombination mediated by insertion sequences (IS). This environment-friendly function is maintained in the degrading population but it has a cost which could diminish its fitness. The loss of genes in the course of evolution being a major mechanism of ecological specialization, we mimicked evolution in vitro by sub-culturing the atrazine-degrading Pseudomonas sp. ADP in a liquid medium containing cyanuric acid as the sole source of nitrogen. After 120 generations, a new population evolved, which replaced the original on…
Scientific opinion on an application by Dow AgroSciences LLC (EFSA-GMO-NL-2012-106) for the placing on the market of genetically modified herbicide-t…
2017
Abstract Soybean DAS‐44406‐6 expresses 5‐enolpyruvyl‐shikimate‐3‐phosphate synthase (2mEPSPS), conferring tolerance to glyphosate‐based herbicides, aryloxyalkanoate dioxygenase (AAD‐12), conferring tolerance to 2,4‐dichlorophenoxyacetic acid (2,4‐D) and other related phenoxy herbicides, and phosphinothricin acetyl transferase (PAT), conferring tolerance to glufosinate ammonium‐based herbicides. The molecular characterisation data and bioinformatics analyses did not identify issues requiring assessment for food/feed safety. The agronomic and phenotypic characteristics revealed no relevant differences between soybean DAS‐44406‐6 and its conventional counterpart, except for pod count, seed cou…
Scientific Opinion on an application by Syngenta (EFSA-GMO-DE-2009-66) for placing on the market of herbicide tolerant and insect resistant maize Bt1…
2015
Question number: EFSA-Q-2009-00444 on request from Competent Authority of Germany; The EFSA GMO Panel previously assessed the four single events combined to produce a four-event stack maize Bt11 × MIR162 × MIR604 × GA21 and did not identify safety concerns. In this opinion, the EFSA GMO Panel assesses the four-event stack maize and all its subcombinations independently of their origin. No new data on the single events, leading to modification of the original conclusions on their safety, were identified. The molecular, agronomic, phenotypic and compositional data on the four-event stack maize did not give rise to safety concerns and there is no reason to expect interactions between the singl…