Differential content of glyphosate and its metabolites in Digitaria insularis biotypes

Abstract

Experiments were carried out in controlled conditions to analyze the role of metabolism of glyphosate in Digitaria insularis (sourgrass) biotypes with differential response to the herbicide. Contents of glyphosate, aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine was detected in leaf tissues by using reversed-polarity capillarity electrophoresis. Glyphosate content in the A biotype increased from 19.7 up to 65.5 µg g fresh weight-1 , whereas decreasing from 19.9 down to 5.0 µg g fresh weight-1 in the B biotype, from 48 up to 168 hours after treatment. At 168 hours after treatment, percentage of the sum of AMPA, glyoxylate, and sarcosine was > 56% in the B biotype, whereas a small percentage of metabolites (< 10%) was found in the A biotype. Thus, the faster herbicide degradation in the B biotype is evidence that a differential metabolism of glyphosate can be conferring its lesser susceptibility to the herbicide.

Isolation of Skeletal Muscle-derived Cells Modeling Neural Crest-Derived Stem Cells for Therapeutic Use in Regenerative Periodontology

“…Varying mechanical methods have been proposed over recent years, each aiming to produce comparable cell suspensions to those gained from tried and tested enzymatic protocols 37,33 . Development of these mechanical methods has been driven by the desire to eliminate enzymatic requirement for both health and economic reasons 32 . The possibility for eliminating the necessity of overnight incubation with expensive enzymes acts as a considerable financial and time saving incentive.…”

“…In the reports mentioned previously, samples of periodontal ligament and palatal rugae were dissociated using enzymatic methods, involving treatments with enzymes such as trypsin, dispase, and collagenase I and II 14,31,27,25 . The limitations of enzymatic digestion surround the facts that these enzymes are both expensive, and often not "xeno-free" 32 . Enzymes sourced from different species of animals, or bacteria could result in serious adverse reactions for the patient, including infection or anaphylaxis 32 .…”

Non-Target-Site Resistance to Herbicides: Recent Developments

“…The reduced uptake of glyphosate has also been shown to impart low-level resistance to glyphosate in several weeds, such as Palmer amaranth [81,83], sourgrass [89], and Johnsongrass [87]. An enhanced metabolism of glyphosate is another mechanism responsible for high tolerance to glyphosate and was observed in some biotypes of sourgrass [95], horseweed [96], and Echinochloa colona [97]. In sourgrass biotypes with a greater tolerance to glyphosate, more than 56% of glyphosate was metabolized into aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine at 168 HAT compared to 10% in susceptible biotypes [95].…”

“…An enhanced metabolism of glyphosate is another mechanism responsible for high tolerance to glyphosate and was observed in some biotypes of sourgrass [95], horseweed [96], and Echinochloa colona [97]. In sourgrass biotypes with a greater tolerance to glyphosate, more than 56% of glyphosate was metabolized into aminomethylphosphonic acid (AMPA), glyoxylate, and sarcosine at 168 HAT compared to 10% in susceptible biotypes [95]. Similar, rapid metabolism of glyphosate was observed in resistant horseweed populations where almost 100% of glyphosate metabolized into glyoxylate, sarcosine, and AMPA within 96 HAT [96].…”

Herbicide resistance and biodiversity: agronomic and environmental aspects of genetically modified herbicide-resistant plants

“…Mutations in the EPSPS target site [81], increased EPSPS mRNA levels [82], EPSPS gene amplification [83], delayed glyphosate translocation [84], sequestration of glyphosate in vacuoles [85], and degradation in the plant [86] have been described. The increased glyphosate use has also promoted species shift among the weed flora, and several grass and broadleaf weeds are becoming problematic weeds [87].…”