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Roundup - Glyphosate Abstracts

Kinetics of 5-enolpyruvylshikimate-3-phosphate synthase inhibition by glyphosate.
FEBS Lett 1983 Apr 5;154(1):127-33
Boocock MR, Coggins JR.

Department of Biochemistry, University of Glasgow, Scotland.

The herbicide glyphosate (N-phosphonomethyl glycine) is a potent reversible inhibitor of the 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase activity of the purified arom multienzyme complex from Neurospora crassa. Inhibition of the EPSP synthase reaction by glyphosate is competitive with respect to phosphoenolpyruvate, with K(i) 1.1 microM, and uncompetitive with respect to shikimate-3-phosphate. The kinetic patterns are consistent with a compulsory order sequential mechanism in which either PEP or glyphosate can bind to an enzyme: shikimate-3-phosphate complex.

Pesticide Roundup Provokes Cell Division Dysfunction at the Level of CDK1/Cyclin B Activation.
Chem Res Toxicol 2002 Mar;15(3):326-31
Marc J, Mulner-Lorillon O, Boulben S, Hureau D, Durand G, Belle R.

Station Biologique de Roscoff, Universite Pierre et Marie Curie (UFR 937), Centre National de la Recherche Scientifique (CNRS, UMR 7127), BP 74, 29682 Roscoff Cedex, France.

To assess human health risk from environmental chemicals, we have studied the effect on cell cycle regulation of the widely used glyphosate-containing pesticide Roundup. As a model system we have used sea urchin embryonic first divisions following fertilization, which are appropriate for the study of universal cell cycle regulation without interference with transcription. We show that 0.8% Roundup (containing 8 mM glyphosate) induces a delay in the kinetic of the first cell cleavage of sea urchin embryos. The delay is dependent on the concentration of Roundup. The delay in the cell cycle could be induced using increasing glyphosate concentrations (1-10 mM) in the presence of a subthreshold concentration of Roundup 0.2%, while glyphosate alone was ineffective, thus indicating synergy between glyphosate and Roundup formulation products. The effect of Roundup was not lethal and involved a delay in entry into M-phase of the cell cycle, as judged cytologically. Since CDK1/cyclin B regulates universally the M-phase of the cell cycle, we analyzed CDK1/cyclin B activation during the first division of early development. Roundup delayed the activation of CDK1/cyclin B in vivo. Roundup inhibited also the global protein synthetic rate without preventing the accumulation of cyclin B. In summary, Roundup affects cell cycle regulation by delaying activation of the CDK1/cyclin B complex, by synergic effect of glyphosate and formulation products. Considering the universality among species of the CDK1/cyclin B regulator, our results question the safety of glyphosate and Roundup on human health.

Roundup inhibits steroidogenesis by disrupting steroidogenic acute regulatory (StAR) protein expression.
Environ Health Perspect 2000 Aug;108(8):769-76
Walsh LP, McCormick C, Martin C, Stocco DM.
Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, Texas, USA.

Recent reports demonstrate that many currently used pesticides have the capacity to disrupt reproductive function in animals. Although this reproductive dysfunction is typically characterized by alterations in serum steroid hormone levels, disruptions in spermatogenesis, and loss of fertility, the mechanisms involved in pesticide-induced infertility remain unclear. Because testicular Leydig cells play a crucial role in male reproductive function by producing testosterone, we used the mouse MA-10 Leydig tumor cell line to study the molecular events involved in pesticide-induced alterations in steroid hormone biosynthesis. We previously showed that the organochlorine insecticide lindane and the organophosphate insecticide Dimethoate directly inhibit steroidogenesis in Leydig cells by disrupting expression of the steroidogenic acute regulatory (StAR) protein. StAR protein mediates the rate-limiting and acutely regulated step in steroidogenesis, the transfer of cholesterol from the outer to the inner mitochondrial membrane where the cytochrome P450 side chain cleavage (P450scc) enzyme initiates the synthesis of all steroid hormones. In the present study, we screened eight currently used pesticide formulations for their ability to inhibit steroidogenesis, concentrating on their effects on StAR expression in MA-10 cells. In addition, we determined the effects of these compounds on the levels and activities of the P450scc enzyme (which converts cholesterol to pregnenolone) and the 3beta-hydroxysteroid dehydrogenase (3beta-HSD) enzyme (which converts pregnenolone to progesterone). Of the pesticides screened, only the pesticide Roundup inhibited dibutyryl [(Bu)(2)]cAMP-stimulated progesterone production in MA-10 cells without causing cellular toxicity. Roundup inhibited steroidogenesis by disrupting StAR protein expression, further demonstrating the susceptibility of StAR to environmental pollutants.

Clinical presentations and prognostic factors of a glyphosate-surfactant herbicide intoxication: a review of 131 cases.
Acad Emerg Med 2000 Aug;7(8):906-10
Lee HL, Chen KW, Chi CH, Huang JJ, Tsai LM.
Department of Emergency Medicine, National Cheng Kung University Hospital, Tainan, Taiwan. hllee@mail.ncku.edu.tw

OBJECTIVE: Suicide attempts with agricultural chemicals are common in southern Taiwan. Among them, glyphosate-surfactant herbicide (GlySH) intoxication has been encountered with increasing frequency. Although a number of reports have described the clinical course and outcomes following ingestion, predictors of serious complications and mortality have not been elucidated. The purpose of this study was to define predictors of serious complications and probable mortality. METHODS: This was a retrospective study of 131 GlySH-intoxicated patients treated at the National Cheng Kung University Hospital from 1988 to 1995. Medical charts were reviewed and clinical and laboratory variables were abstracted, looking for predictors of mortality. RESULTS: The most common symptoms included sore throat (79.5%), and nausea with or without vomiting (73.8%). The most common laboratory findings were leukocytosis (68.0%), low serum bicarbonate (48.1%), and acidosis (35.8%). Overall, 11 of 131 patients (8.4%) died; the mean +/- SEM time to death was 2.8 +/- 0.8 days after presentation. When comparing the clinical and laboratory characteristics among the survivor and fatality groups, significant differences were identified. Respiratory distress, pulmonary edema, respiratory distress necessitating intubation, shock (systolic blood pressure less than 90 mm Hg), altered consciousness, abnormal chest x-ray, renal failure necessitating hemodialysis, larger amount of ingestion (>200 mL), and hyperkalemia were predictors highly associated with poor outcomes and mortality. Using multiple logistic regression, three predictors were identified, which may predict mortality in severely intoxicated patients. CONCLUSIONS: In managing patients who have larger amount of GlySH ingestion, airway protection, early detection of pulmonary edema, and prevention of further pulmonary damage and renal damage appear to be of critical importance.

Hypersensitivity vasculitis caused by the herbicide containing the isopropylamine salt of glyphosate
[Article in Japanese]
Nippon Naika Gakkai Zasshi 2000 Jul 10;89(7):1424-6
Asahi T, Ohta M, Okuda K, Hattori K, Okada E.
Department of Internal Medicine, Takaoka City Hospital.

In vitro studies of cellular and molecular developmental toxicity of adjuvants, herbicides, and fungicides commonly used in Red River Valley, Minnesota.
J Toxicol Environ Health A 2000 Jul 28;60(6):423-39
Lin N, Garry VF.
Environmental Medicine and Pathology, University of Minnesota, Minneapolis 55414, USA.

Recent epidemiologic studies showed increased frequency of birth defects in pesticide applicators and general population of the Red River Valley, Minnesota. These studies further indicated that this crop growing area used more chlorophenoxy herbicides and fungicides than elsewhere in Minnesota. Based on frequency of use and known biology, certain herbicides, pesticide additives, fungicides, and mycotoxins are suspect agents. To define whether these agents affect developmental endpoints in vitro, 16 selected agrochemicals were examined using the MCF-7 breast cancer cell line. In the flow cytometric assay, cell proliferation in this estrogen-responsive cell line indicates xenobiotic-mediated estrogenic effects. Cell viability, morphology, ploidy, and apoptosis were incorporated in this assay. Data showed that the adjuvants X-77 and Activate Plus induced significant cell proliferation at 0.1 and 1 microg/ml. The commercial-grade herbicides 2,4-D LV4 and 2,4-D amine induced cell proliferation at 1 and 10 microg/ml. The reagent-grade 2,4-D products failed to induce proliferation over the same concentration range, suggesting that other ingredients in the commercial products, presumably adjuvants, could be a factor in these results. The fungicides triphenyltin and mancozeb induced apoptosis at concentrations of 4.1 microg/ml (10(-5) M) and 50 microg/ml, respectively. Triphenyltin also induced aneuploidy (C2/M arrest) at 0.41 microg/ml (10(-6) M). Data provide a mechanistic step to understanding human reproductive and developmental effects in populations exposed to these agrochemicals, and initiative to focusing limited resources for future in vivo animal developmental toxicity studies.

Use of the Drosophila wing spot test in the genotoxicity testing of different herbicides.
Environ Mol Mutagen 2000;36(1):40-6
Kaya B, Creus A, Yanikoglu A, Cabre O, Marcos R.
Department of Biology, Faculty of Arts and Sciences, Akdeniz University, Antalya, Turkey.

Four herbicides, namely propanil, maleic hydrazide, glyphosate, and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), were investigated for genotoxicity in the wing spot test of Drosophila melanogaster. The herbicides were administered by chronic feeding to 3-day-old larvae. Two different crosses, a standard (ST) and a high-bioactivation (HB) cross, involving the flare-3 (flr(3)) and the multiple wing hairs (mwh) markers, were used. The HB cross uses flies characterized by an increased cytochrome P-450-dependent bioactivation capacity, which permits a more efficient biotransformation of promutagens and procarcinogens. In both crosses, the wings of the two types of progeny, which are inversion-free marker heterozygotes and balancer heterozygotes, were analyzed. Maleic hydrazide and glyphosate proved to be more genotoxic in the ST cross, whereas propanil appeared to be slightly more genotoxic in the HB cross. On the other hand, the herbicide 2,4,5-T increased the mutation frequency for only the small single spots in the ST cross.

Determination of glyphosate residues in plants by precolumn derivatization and coupled-column liquid chromatography with fluorescence detection.
J AOAC Int 2000 May-Jun;83(3):728-34
Hernandez F, Hidalgo C, Sancho JV.
University Jaume I, Experimental Sciences Department, Analytical Chemistry, Castello, Spain.

A rapid method was developed for the trace-level determination of glyphosate in olives. After extraction of the glyphosate with water-dichloromethane and simultaneous removal of the olive oil, an aliquot of the aqueous extract is derivatized with 9-fluoroenylmethyl chloroformate (9-fluorenylmethoxycarbonyl chloride; FMOC-CI) to produce a highly fluorescent derivative. A 2 mL aliquot of this extract is injected directly into a coupled-column liquid chromatography system with fluorimetric detection (LC/LC-FD). The procedure was validated by recovery experiments at 3 spiking levels; recoveries ranged from 80 to 97% with relative standard deviations of 3-6%. The limits of detection and quantitation were estimated to be 0.01 and 0.05 mg/kg, respectively. The method was also applied to other plant materials, i.e., tomato plants, strawberry plants, and pear trees (branches, leaves, and fruits) suspected to be contaminated by glyphosate. In all these cases, the extraction was performed in aqueous media. The derivatization reaction was modified by increasing the FMOC-CI concentration, to ensure a quantitative reaction between analyte and reagent in the presence of high levels of coextractives, which also react with FMOC-CI. The final determination was by LC/LC-FD, yielding a rapid, selective, and sensitive method for the determination of glyphosate residues in these samples. The method was tested with real-world samples after application of glyphosate to the surrounding area of crops.

!!!! This study is quite precious. It is the antithesis of other findings. !!!!

Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans.
Regul Toxicol Pharmacol 2000 Apr;31(2 Pt 1):117-65
Williams GM, Kroes R, Munro IC.
Department of Pathology, New York Medical College, Valhalla 10595, USA.

Reviews on the safety of glyphosate and Roundup herbicide that have been conducted by several regulatory agencies and scientific institutions worldwide have concluded that there is no indication of any human health concern. Nevertheless, questions regarding their safety are periodically raised. This review was undertaken to produce a current and comprehensive safety evaluation and risk assessment for humans. It includes assessments of glyphosate, its major breakdown product [aminomethylphosphonic acid (AMPA)], its Roundup formulations, and the predominant surfactant [polyethoxylated tallow amine (POEA)] used in Roundup formulations worldwide. The studies evaluated in this review included those performed for regulatory purposes as well as published research reports. The oral absorption of glyphosate and AMPA is low, and both materials are eliminated essentially unmetabolized. Dermal penetration studies with Roundup showed very low absorption. Experimental evidence has shown that neither glyphosate nor AMPA bioaccumulates in any animal tissue. No significant toxicity occurred in acute, subchronic, and chronic studies. Direct ocular exposure to the concentrated Roundup formulation can result in transient irritation, while normal spray dilutions cause, at most, only minimal effects. The genotoxicity data for glyphosate and Roundup were assessed using a weight-of-evidence approach and standard evaluation criteria. There was no convincing evidence for direct DNA damage in vitro or in vivo, and it was concluded that Roundup and its components do not pose a risk for the production of heritable/somatic mutations in humans. Multiple lifetime feeding studies have failed to demonstrate any tumorigenic potential for glyphosate. Accordingly, it was concluded that glyphosate is noncarcinogenic. Glyphosate, AMPA, and POEA were not teratogenic or developmentally toxic. There were no effects on fertility or reproductive parameters in two multigeneration reproduction studies with glyphosate. Likewise there were no adverse effects in reproductive tissues from animals treated with glyphosate, AMPA, or POEA in chronic and/or subchronic studies. Results from standard studies with these materials also failed to show any effects indicative of endocrine modulation. Therefore, it is concluded that the use of Roundup herbicide does not result in adverse effects on development, reproduction, or endocrine systems in humans and other mammals. For purposes of risk assessment, no-observed-adverse-effect levels (NOAELs) were identified for all subchronic, chronic, developmental, and reproduction studies with glyphosate, AMPA, and POEA. Margins-of-exposure for chronic risk were calculated for each compound by dividing the lowest applicable NOAEL by worst-case estimates of chronic exposure. Acute risks were assessed by comparison of oral LD50 values to estimated maximum acute human exposure. It was concluded that, under present and expected conditions of use, Roundup herbicide does not pose a health risk to humans.

Effects of acute exposure to a commercial formulation of glyphosate on the tadpoles of two species of anurans.
Bull Environ Contam Toxicol 2001 Oct;67(4):483-8
Smith GR.
Department of Biology, Denison University, Granville, OH 43023, USA.

Analysis of glyphosate and its metabolite, aminomethylphosphonic acid, in agricultural products by HPLC

Shokuhin Eiseigaku Zasshi 2001 Oct;42(5):304-8

[Article in Japanese]

Takahashi K, Horie M, Aoba N.

Saitama Institute of Public Health: 639-1, Kamiokubo, Saitama-shi, Saitama 338-0824, Japan.

An analytical method for residues of the herbicide glyphosate [GLY: N-(phosphonomethyl)-glycine] and its metabolite (AMPA: aminomethylphosphonic acid) in agricultural products is described. GLY and AMPA were extracted with water (soybeans extract was moreover treated with acetone), and purified by application to a dual mini-cartridge column (octadecyl-bonded silica gel and cation-exchange silica gel) system. GLY was derivatized with 9-fluorenylmethylchloroformate, and determined by HPLC with fluorescence detection. AMPA determination was performed by HPLC employing postcolumn fluorogenic labeling with o-phthalaldehyde-mercaptoethanol. The detection limits for GLY and AMPA were 0.04 microgram/g (soybean: 0.08 microgram/g), and both recoveries from samples to which the compounds were added at the 0.2 microgram/g level (soybean: 1.0 microgram/g) were more than 65%.

Validation of PCR methods for quantitation of genetically modified plants in food.
J AOAC Int 2001 Nov-Dec;84(6):1855-64
Hubner P, Waiblinger HU, Pietsch K, Brodmann P.
Kantonales Labor Zurich, Switzerland.

For enforcement of the recently introduced labeling threshold for genetically modified organisms (GMOs) in food ingredients, quantitative detection methods such as quantitative competitive (QC-PCR) and real-time PCR are applied by official food control laboratories. The experiences of 3 European food control laboratories in validating such methods were compared to describe realistic performance characteristics of quantitative PCR detection methods. The limit of quantitation (LOQ) of GMO-specific, real-time PCR was experimentally determined to reach 30-50 target molecules, which is close to theoretical prediction. Starting PCR with 200 ng genomic plant DNA, the LOQ depends primarily on the genome size of the target plant and ranges from 0.02% for rice to 0.7% for wheat. The precision of quantitative PCR detection methods, expressed as relative standard deviation (RSD), varied from 10 to 30%. Using Bt176 corn containing test samples and applying Bt176 specific QC-PCR, mean values deviated from true values by -7to 18%, with an average of 2+/-10%. Ruggedness of real-time PCR detection methods was assessed in an interlaboratory study analyzing commercial, homogeneous food samples. Roundup Ready soybean DNA contents were determined in the range of 0.3 to 36%, relative to soybean DNA, with RSDs of about 25%. Taking the precision of quantitative PCR detection methods into account, suitable sample plans and sample sizes for GMO analysis are suggested. Because quantitative GMO detection methods measure GMO contents of samples in relation to reference material (calibrants), high priority must be given to international agreements and standardization on certified reference materials.

A new type of class I bacterial 5-enopyruvylshikimate-3-phosphate synthase mutants with enhanced tolerance to glyphosate.
Biochim Biophys Acta 2001 Nov 7;1568(1):1-6
He M, Yang ZY, Nie YF, Wang J, Xu P.
The Key Laboratory of Gene Engineering of Education Ministry, Zongshan University, Guangzhou, PR China.

Glyphosate or Roundup is the most extensively used herbicide for broad-spectrum control of weeds. Glyphosate inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), a key enzyme in the aromatic amino acid biosynthetic pathway in microorganisms and plants. Applying the staggered extension process, we randomly mutated and recombined the aroA genes of Salmonella typhimurium and Escherichia coli to obtain four variants that exhibit significantly enhanced tolerance to glyphosate. All four mutants are chimeras of the two parental genes and, in addition, three of them carry one or more de novo point mutations. None of the amino acid substitutions in the mutants was in a position previously known to be important for catalysis or substrate binding. Kinetic analysis of EPSPS activity from these mutants indicated that the tolerance was attributed to a 2-10-fold increased specific activity, 0.4-8-fold reduced affinity to glyphosate, and 2.5-19-fold decreased K(m) for phosphoenolpyruvate. Such mutants will be instrumental for the structural and function study of the enzyme and for the generation of transgenic crops resistant to the herbicide.

Automated trace level determination of glyphosate and aminomethyl phosphonic acid in water by on-line anion-exchange solid-phase extraction followed by cation-exchange liquid chromatography and post-column derivatization.
J Chromatogr A 2001 Oct 12;932(1-2):83-90
Patsias J, Papadopoulou A, Papadopoulou-Mourkidou E.
Pesticides Science Laboratory, Aristotle University of Thessaloniki, Greece.

An automated method based on the on-line coupling of anion-exchange solid-phase extraction (SPE) and cation-exchange liquid chromatography followed by post-column derivatization and fluorescence detection has been developed for the trace level determination of glyphosate and its primary conversion product aminomethyl phosphonic acid (AMPA) in water. PRP-X100 poly(styrene-divinylbenzene)-trimethylammonium anion-exchange cartridges (20 x 2 mm, 10 microm) were selected for the SPE of glyphosate and AMPA. The ionic compounds present in the samples strongly influenced the extraction of both analytes; however, when an on-line ion-exchange clean-up step was introduced before sample SPE, the problem was largely solved. By processing 100-ml samples detection limits better than 0.02 microg/l for glyphosate and 0.1 microg/l for AMPA were achieved in river water. Both analytes were unstable in solution and the approach of storing samples on the PRP-X100 SPE cartridges was evaluated for a period of 1 month under three different storage conditions (deep freeze, refrigeration and 20 degrees C).

Investigation of the herbicide glyphosate and the plant growth regulators chlormequat and mepiquat in cereals produced in Denmark.
Food Addit Contam 2001 Oct;18(10):898-905
Granby K, Vahl M.
Institute of Food Research and Nutrition, Danish Veterinary and Food Administration, Soborg. kgr@fdir.dk

An LC-MS/MS method for analysing glyphosate and aminomethylphosphonic acid (AMPA) in cereals was developed. The method is based on extraction with water and detection of the ions from the fragmentation m/z 170-->88 (glyphosate) and m/z 112-->30 (AMPA), using electrospray interface in the positive mode. Investigation from the harvests of 1998 and 1999 showed residues of glyphosate and/or its degradation product AMPA in more than half of the cereal samples produced in Denmark. The average concentration of glyphosate in 46 samples from the 1999 harvest was 0.11 mg/kg compared with 0.08 mg/kg for the 1998 harvest (n = 49). Thus, the figures were well below the maximum residue limit (MRL) and no violations were observed. The plant growth regulators chlormequat and/or mepiquat were investigated in cereals from the Danish harvest of 1999 where 83% of the samples contained chlormequat (n = 46) compared with 87% of the samples from the 1997 harvest (n = 52). The average concentration of chlormequat in 1999 was 0.32 mg/kg compared with 0.23 mg/kg in 1997. At 2.9 mg/kg, one sample of wheat bran was exceeding the MRL of 2 mg/kg for wheat. The intakes of the pesticides through the diet of cereals were estimated to comprise 0.04% of the acceptable daily intake (ADI) for glyphosate and 1% of the ADI for chlormequat for an adult Dane.

Metabolism of the phosphonate herbicide glyphosate by a non-nitrate-utilizing strain of Penicillium chrysogenum.
Pest Manag Sci 2001 Sep;57(9):815-21
Klimek M, Lejczak B, Kafarski P, Forlani G.
Department of Genetics and Microbiology, University of Pavia, I-27100 Pavia, Italy.

A Penicillium chrysogenum strain was isolated for its ability to grow in minimal medium containing the herbicide glyphosate as the only nitrogen source. The presence of concentrations up to 25 mM progressively stimulated the fungal growth rate, which was negligible in media lacking reduced nitrogen. However, glyphosate utilization never exceeded 1 mmol g-1 mycelial dry mass, and below a threshold concentration both herbicide uptake and fungal growth were subject to a lag phase, suggesting that the herbicide may enter the cell by either simple passive diffusion or inducible carriers. Amino acids, possible products of glyphosate breakdown, as well as ammonia, were found to replace the herbicide in restoring mycelial growth. Cells were devoid of detectable nitrate reductase activity, thus the isolate seems to be impaired in its ability to convert nitrate to ammonium. In vitro activity of 5-enol-pyruvyl-shikimate-3-phosphate synthase, the target site of glyphosate action, was highly sensitive to the herbicide. Fungal growth rate was considerably lower when the herbicide was also the only phosphorus source, whereas glyphosate utilization was substantially unaffected, suggesting an unusual route for its degradation. Herbicide metabolism was strongly reduced when other sources of organic nitrogen were made available.

PCR-based detection of genetically modified soybean and maize in raw and highly processed foodstuffs.
Biotechniques 2001 Aug;31(2):426-9
Tengel C, Schussler P, Setzke E, Balles J, Sprenger-Haussels M.
QIAGEN GmbH, Hilden, Germany.

The PCR method has proved to be an invaluable tool for the specific and sensitive detection of genetically modified material (e.g., Roundup Ready Soybean and Bt-176 "Maximizer" Maize) in foodstuffs. The first step in the procedure, namely the purification of nucleic acids from the sample, is often the deciding factor in the production of meaningful results. In this study, we present two procedures that enable an efficient isolation of trace amounts of genetic material from both raw and highly processed foodstuffs. We show that for optimal, PCR-ready DNA purification from highly processed foodstuffs and PCR inhibitor-rich substances--such as cocoa-containing products--adapted protocols for the QIAGEN QIAamp DNA Stool Mini Kit can be utilized. For complete DNA isolation from raw foodstuffs, a protocol using the DNeasy Plant Mini Kit is presented.

Effects of the herbicide Roundup on the ultrastructural pattern of hepatocytes in carp (Cyprinus carpio).
Mar Environ Res 2000 Jul-Dec;50(1-5):263-6
Szarek J, Siwicki A, Andrzejewska A, Terech-Majewska E, Banaszkiewicz T.
Department of Forensic and Administration Veterinary Medicine, Warmia and Masuria University in Olsztyn, Oczapowskiego St. 13, 10-717 Olsztyn, Poland. szarekjo@polbox.com

Experimental studies were performed on healthy, 80-100 g carp (Cyprinus carpio). Fish were exposed by emersion in Roundup (205 mg of glyphosate/l or 410 mg of glyphosate/l) in concentrations of 40- to 20-fold lower than those used in practice. Electron microscopy revealed that the herbicide caused appearance of myelin-like structures in carp hepatocytes, swelling of mitochondria and disappearance of internal membrane of mitochondria in carp at both exposure concentrations. It means that Roundup was harmful to carp when used in applied concentrations. Results of these studies enhance our knowledge of ultrastructural pathomorphology of fish organs following exposure to Roundup.

Parkinsonism after glycine-derivate exposure.
Mov Disord 2001 May;16(3):565-8
Barbosa ER, Leiros da Costa MD, Bacheschi LA, Scaff M, Leite CC.
Divisao de Clinica Neurologica, Hospital das Clinicas da Faculdade, Medicina da Universidade, Sao Paulo, Sao Paulo, Brazil. egbertob@8415.com.br

This 54-year-old man accidentally sprayed himself with the chemical agent glyphosate, a herbicide derived from the amino acid glycine. He developed disseminated skin lesions 6 hours after the accident. One month later, he developed a symmetrical parkinsonian syndrome. Two years after the initial exposure to glyphosate, magnetic resonance imaging revealed hyperintense signal in the globus pallidus and substantia nigra, bilaterally, on T2-weighted images. Levodopa/benserazide 500/125 mg daily provided satisfactory clinical outcome.

Dynamics of glyphosate and aminomethylphosphonic acid in a forest soil in Galicia, north-west Spain.
Sci Total Environ 2001 Apr 23;271(1-3):135-44
Veiga F, Zapata JM, Fernandez Marcos ML, Alvarez E.
Department of Soil Science, University of Santiago de Compostela, Escuela Politecnica Superior, Lugo, Spain.

Residues of the herbicide glyphosate (N-phosphonomethylglicine) and its main metabolite, aminomethylphosphonic acid (AMPA), were determined in a forest soil in north-west Spain, previously treated with 5 and 8 l ha(-1) of glyphosate. Both products were monitored in the solid and liquid soil phases for an 8-week period after the treatment. Soil samples were extracted by KH2PO4. Concentrated extracts and liquid phase samples were derivatized with 9-fluorenylmethyl chloroformate (FMOC) before determination by HPLC using an anion exchange column and spectrofluorometric detection. The treated soil peaked at 6.9 microg g(-1) of glyphosate, whereas soil water samples peaked at 0.74 microg ml(-1) of glyphosate. One month after the treatment, both glyphosate and AMPA concentrations in soil and water samples were almost negligible. AMPA peaked at 0.77 microg ml(-1) in soil water samples. Glyphosate and AMPA exhibited high vertical mobility in the treated soil, quickly reaching high concentrations in subsurface horizons where the degradation is slower.

Influence of glyphosate on amino acid composition of Egyptian broomrape.
J Agric Food Chem 2001 Mar;49(3):1524-8
Nandula VK, Westwood JH, Foster JG, Foy CL.
Department of Plant Pathology, Physiology and Weed Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0331, USA.

The parasitic plant broomrape is entirely dependent on its host for reduced carbon and nitrogen and is also susceptible to inhibition by glyphosate that is translocated to the parasite through a host. Studies were conducted to examine the effect of broomrape parasitism on amino acid concentrations of two hosts: common vetch that is tolerant of low levels of glyphosate and oilseed rape that has been genetically engineered for glyphosate resistance. The influence of glyphosate on the amino acid content of broomrape and the two hosts was also examined. Amino acid concentrations in leaves and roots of parasitized common vetch plants were generally similar to those of the corresponding tissues of nonparasitized plants. Amino acid concentrations in broomrape were lower than those of the parasitized common vetch root. For common vetch, glyphosate applied at rates that selectively inhibited broomrape growth did not alter individual amino acid concentrations in the leaves, but generally increased amino acid levels at 0.18 kg ha-1. Glyphosate application also increased the amino acid concentrations, with the exception of arginine, of broomrape growing on common vetch and did not generally influence concentrations in leaves or roots of common vetch. In oilseed rape, parasitization by broomrape generally led to higher amino acid concentrations in leaves but lower concentrations in roots of parasitized plants. Broomrape had higher amino acid concentrations than roots of the parasitized oilseed rape. Glyphosate applied at 0.25 and 0.5 kg ha-1 generally increased the amino acid concentrations in oilseed rape leaves, but the 0.75 kg ha-1 application caused the amino acid concentrations to decrease compared to those of untreated plants. In oilseed rape root the general trend was an increase in the concentration of amino acids at the two highest rates of glyphosate. Individual amino acid concentrations in broomrape attachments growing on oilseed rape were generally increased following glyphosate application of 0.25 kg ha-1. These results indicate that low rates of glyphosate alter amino acid profiles in both host and broomrape and raise questions about the regulation of amino acid metabolism in the parasite.

Influence of paraquat, glyphosate, and cadmium on the activity of some serum enzymes and protein electrophoretic behavior (in vitro).
J Environ Sci Health B 2001 Jan;36(1):29-42
El-Demerdash FM, Yousef MI, Elagamy EI.
Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, Egypt.

In vitro study for the determination of the toxicity of some pesticides (glyphospate and paraquat) and cadmium chloride (CdCl2) on the activities of serum acetylcholinesterase (AChE), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (AlP), and acid phosphatase (AcP) is described. Changes in electrophoretic patterns of serum proteins were also tested. Results revealed that glyphosate was effective on all enzymes except AcP. Its IC50 values (the concentration of compound that inhibits 50% of the enzyme activity in 1 h at 37 degrees C) were 714.3, 750, 54.2, 270.8, and 71.4 mM for AChE, LDH, AST, ALT, and AlP, respectively. The inhibitory effect of paraquat varied markedly among all enzymes. The IC50 values of paraquat were 321.4 and 750 mM for AST and ALT, respectively. It had mild effect on AChE and LDH; and no effect on the activities of AlP and AcP. The effect of CdCl2 was pronounced with AChE, ALT, AlP, and AcP, and no effect on LDH and AST was found. The corresponding IC50 values were 77.7, 22.2, 33.3, and 83.3 mM for AChE, ALT, AlP, and AcP, respectively. Polyacrylamide gel electrophoretic patterns of serum proteins showed marked differences with glyphosate and CdCl2 but not with paraquat. The results suggest that the in vitro enzyme-activity test seems to have a potential for the assessment of pesticide and heavy metal toxicity.

Interaction of the herbicide glyphosate with its target enzyme 5-enolpyruvylshikimate 3-phosphate synthase in atomic detail.
Proc Natl Acad Sci U S A 2001 Feb 13;98(4):1376-80
Schonbrunn E, Eschenburg S, Shuttleworth WA, Schloss JV, Amrhein N, Evans JN, Kabsch W.
Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA. eschoenb@eagle.cc.ukans.edu

Biosynthesis of aromatic amino acids in plants, many bacteria, and microbes relies on the enzyme 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, a prime target for drugs and herbicides. We have identified the interaction of EPSP synthase with one of its two substrates (shikimate 3-phosphate) and with the widely used herbicide glyphosate by x-ray crystallography. The two-domain enzyme closes on ligand binding, thereby forming the active site in the interdomain cleft. Glyphosate appears to occupy the binding site of the second substrate of EPSP synthase (phosphoenol pyruvate), mimicking an intermediate state of the ternary enzyme.substrates complex. The elucidation of the active site of EPSP synthase and especially of the binding pattern of glyphosate provides a valuable roadmap for engineering new herbicides and herbicide-resistant crops, as well as new antibiotic and antiparasitic drugs.

Long-term fate of glyphosate associated with repeated rodeo applications to control smooth cordgrass (Spartina alterniflora) in Willapa Bay, Washington.
Arch Environ Contam Toxicol 2001 Feb;40(2):179-83
Kilbride KM, Paveglio FL.
U.S. Fish and Wildlife Service, Refuges and Wildlife, Division of Refuge Biology, Vancouver, Washington 98665, USA. Kevin-kilbride@fws.gov

Cordgrasses (Spartina sp.) are exotic, invasive species that threaten to degrade the intertidal zones of estuaries along the West Coast of North America. Integrated pest management (IPM) strategies primarily focus on the use of aerial and ground applications of Rodeo in conjunction with mowing, but IPM treatments over multiple years usually are necessary to control Spartina. Although information exists regarding the short-term fate and effects to marine biota of a single Rodeo application to control Spartina, little information is available regarding the fate and biotic effects associated with repeated Rodeo applications necessary for control. Consequently, we conducted a 3-year study to assess the short- and long-term fate and potential effects to marine biota associated with repeated applications of Rodeo to control smooth cordgrass in a southwestern Washington estuary. At each of three intertidal locations in Willapa Bay, we established plots on exposed mudflats and along the edge of a Spartina meadow that were hand sprayed with Rodeo (5% solution) and LI-700 (2% solution) during July 1997 and 1998. Glyphosate concentrations in sediment from mudflat plots declined 88% to 96% from 1 day posttreatment in 1997 to 1 year after the second Rodeo applications in 1999. In contrast, glyphosate concentrations in Spartina plots increased 231% to 591% from 1997 to 1999 because Spartina rhizomes likely did not readily metabolize or exude it. Comparison of concentrations from mudflat and Spartina plots with toxicity test values for marine biota indicates that under worst-case conditions short- and long-term detrimental effects to aquatic biota from repeated application of Rodeo for Spartina control would be highly unlikely.

Glyphosate inhibits melanization of Cryptococcus neoformans and prolongs survival of mice after systemic infection.
J Infect Dis 2001 Apr 1;183(7):1093-9
Nosanchuk JD, Ovalle R, Casadevall A.
Department of Medicine, Division of Infectious Diseases, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

Cryptococcus neoformans is a major fungal pathogen and is a relatively common cause of life-threatening meningoencephalitis. Glyphosate is a widely used herbicide that inhibits the synthesis of aromatic amino acids via the shikimate acid pathway. This study investigated the effects of glyphosate on C. neoformans growth, melanization, and murine infection. C. neoformans was relatively resistant to glyphosate, requiring concentrations >250 microg/mL for inhibition. Melanization of C. neoformans in the presence of L-dopa was inhibited by subinhibitory concentrations of glyphosate. Glyphosate inhibited autopolymerization of L-dopa and oxidation of L-epinephrine by cryptococcal cells, which is mediated by a laccase. Administration of glyphosate to mice infected with C. neoformans delayed melanization of yeast cells in vivo and prolonged average mouse survival. The results suggest that inhibition of melanization in vivo may facilitate control of C. neoformans infection.

Effect of the herbicide glyphosate on enzymatic activity in pregnant rats and their fetuses.

Environ Res 2001 Mar;85(3):226-31

Daruich J, Zirulnik F, Gimenez MS.

Catedra de Bioquimica Molecular, Area Quimica Biologica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, Argentina.

To prevent health risk from environmental chemicals, particularly for progeny, we have studied the effects of the herbicide glyphosate on several enzymes of pregnant rats. Glyphosate is an organophosphorated nonselective agrochemical widely used in many countries including Argentina and acts after the sprout in a systemic way. We have studied three cytosolic enzymes: isocitrate dehydrogenase-NADP dependent, glucose-6-phosphate dehydrogenase, and malic dehydrogenase in liver, heart, and brain of pregnant Wistar rats. The treatment was administered during the 21 days of pregnancy, with 1 week as an acclimation period. The results suggest that maternal exposure to agrochemicals during pregnancy induces a variety of functional abnormalities in the specific activity of the enzymes in the studied organs of the pregnant rats and their fetuses.

Effects of 2,4-D, glyphosate and paraquat on growth, photosynthesis and chlorophyll-a synthesis of Scenedesmus quadricauda Berb 614.
Chemosphere 2000 Jul;41(1-2):177-82
Wong PK.
Department of Biology, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong SAR, People's Republic of China. pkwong@cuhk.edu.hk

The effects of 2,4-D, glyphosate and paraquat on growth, photosynthesis and chlorophyll-a synthesis by a freshwater green alga, Scenedesmus quadricauda Berb 614, were determined. These herbicides are the most often used in Hong Kong. Within the concentration range 0.02-200 mg/l, paraquat was more toxic than glyphosate and 2,4-D to the growth, photosynthesis and chlorophyll-a synthesis. The presence of 0.02, 0.2 or 2 mg/l of 2,4-D was not toxic to the alga. Algal growth, photosynthesis and chlorophyll-a synthesis were stimulated by the presence of low concentrations (0.02 or 0.2 and 0.02 mg/l, respectively) of 2,4-D and glyphosate. The presence of 0.02 or 0.2 mg/l of paraquat, 2 mg/l of glyphosate or 20 mg/l of 2,4-D was significantly inhibitory to the three test parameters, whereas the presence of 2 or more mg/l of paraquat, 20 or more mg/l of glyphosate or 200 mg/l of 2,4-D completely inhibited algal growth, photosynthesis and chlorophyll-a synthesis. The use of the alga as a bio-indicator of herbicide contamination in freshwater environment was discussed.

Influence of incubation temperature on the behavior of triethylamine-extractable glyphosate (N-phosphonomethylglycine) in four soils.
J Agric Food Chem 1999 Jun;47(6):2459-67
Eberbach PL.
School of Agriculture, Charles Sturt University-Riverina, Wagga, Australia. peberbach@csu.edu.au

The behavior of glyphosate, extracted from four soils using aqueous triethylamine, was investigated at two temperatures. For each soil, and at both temperatures, there was a marked loss in the amount of extractable glyphosate immediately after addition of the herbicide to soil. This rapid loss of glyphosate was ascribed to adsorption of the herbicide into a nonextractable form. For three of the four soils used when incubated at 25 degrees C, the rates of loss of extractable glyphosate were similar to previously measured rates of degradation of this herbicide in these soils. However, loss of extractable glyphosate from the Culgoa clay loam was due not only to substrate degradation but also to slow sorption of glyphosate into the nonextractable form in this soil over the experimental period. For the Rutherglen and Walpeup soils, when incubated at 10 degrees C, the rates of loss of extractable glyphosate were half of the previously measured rate of degradation of this herbicide in these soils. However, there was no measured loss of extractable glyphosate from the Wimmera clay. As previous work has shown glyphosate to decompose readily in these soils at this temperature, these findings suggest that desorption of glyphosate may occur at a rate greater than degradation at this temperature and, hence, that temperature may play a pivotal role in sorption processes. Investigations with these soils when sterilized by gamma-irradiation showed that for the Walpeup, Wimmera, and Rutherglen soils, sorption was complete soon after the addition of the herbicide; however, for the Culgoa soil, further adsorption occurred over the entire experimental period.

Glyphosate adsorption on soils of different characteristics. Influence of copper addition.
Chemosphere 2000 Jan;40(1):103-7
Morillo E, Undabeytia T, Maqueda C, Ramos A.
Instituto de Recursos Naturales y Agrobiologia (CSIC), Sevilla, Spain. morillo@irnase.csic.es

Results of glyphosate (GPS) adsorption on three soils of different characteristics show that the interaction of this pesticide with the soils was not related to their CEC and clay minerals content, but to the content of iron and aluminum amorphous oxides and organic matter. The presence of Cu in treatment solutions enhanced GPS adsorption, due to several reasons: GPS coordinates strongly to Cu, and Cu GPS complexes formed seem to have higher ability to be adsorbed on the soil than free GPS; GPS adsorption can take place on sites where Cu was previously adsorbed, acting as a bridge between the soil and GPS; when Cu was present the solution pH decreased, and GPS adsorption increased, since lower pHs lead to the formation of GPS species with lower negative charge, which are adsorbed more easily on the negatively charged soil surfaces.

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