Environmental exposure assessment of co-formulants in plant protection products under REACH.

It is a regulatory requirement to assess co-formulants in plant protection products (PPP) under the European Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation. The standard environmental exposure assessment framework for chemicals under REACH is a multicompartmental mass-balanced model and, at the local scale, is designed for use with urban (wide dispersive) or industrial (point source) emissions. However, the environmental release of co-formulants used in PPP is to agricultural soil and indirectly to waterbodies adjacent to a field and, for sprayed products, to the air.

REACH Worker Exposure Model for Co-formulants Used in Plant Protection Products.

Background: Substances used as co-formulants in plant protection products (PPP) may require registration under Regulation (EC) No. 1907/2006 (REACH), and additionally where an exposure assessment is required, this must take into consideration the specifics of the PPP use.

Objectives: This work reports a customized screening level model developed to support human health risk assessment of operators, workers, and bystanders (OWB) for co-formulants used in PPP.

Development of REACH Generic Exposure Scenarios for Substances Used as Coformulants in Plant Protection Products.

This article reviews the interactions between the REACH (Registration, Evaluation, Authorization and restriction of Chemicals) regulation and the plant protection product regulation for substances used as coformulants in the European Union, and describes generic exposure scenarios developed for their exposure and risk assessment. The REACH exposure scenarios describe the operational conditions and risk management measures used in the risk assessment of a coformulant, and as such these translate as the boundaries of safe use. The generic exposure scenarios are designed to be simple, and closely integrate with REACH use descriptors and customized exposure models.

The mycotoxin patulin reacts with DNA bases with and without previous conjugation to GSH: implication for related α,β-unsaturated carbonyl compounds?

The α,β-unsaturated carbonyl group is recognized as alert for mutagenicity, attributed to (1) its direct reaction with DNA, counteractable by glutathione (GSH), and (2) oxidative stress caused indirectly by GSH depletion. Accordingly, the α,β,γ,δ-unsaturated lactone patulin (PAT), a mycotoxin detected in fruits and products derived thereof, is known to induce gene, chromosome, and genome mutations in vitro, its mutagenicity correlating inversely with intracellular GSH levels. Thus, the reactivity of PAT against DNA bases and nucleosides in the absence and presence of GSH and glutathione S-transferases (GSTs) was investigated under cell-free conditions using HPLC mass spectrometry techniques for identification of reaction products.

Electrophilic properties of patulin. N-acetylcysteine and glutathione adducts.

In our studies on the electrophilic properties of the mycotoxin patulin (PAT), we have now investigated the nonenzymatic reaction of PAT with the thiol-containing tripeptide glutathione and its metabolic degradation product N-acetyl-L-cysteine (NAC). Adduct formation in aqueous phosphate buffer (pH 7.4) was studied by analytical HPLC/DAD, and most of the products were isolated by preparative HPLC.

Electrophilic properties of patulin. Adduct structures and reaction pathways with 4-bromothiophenol and other model nucleophiles.

The mycotoxin patulin (PAT) is believed to exert its cytotoxic and chromosome-damaging effects by forming covalent adducts with essential cellular thiols. Since the chemical structures of such adducts are unknown to date, we have studied the reaction of PAT and its O-acetylated derivative with the monofunctional thiol model compound 4-bromothiophenol (BTP), which was chosen due to analytical advantages. By means of analytical and preparative high-performance liquid chromatography, 16 adducts of PAT and 3 adducts of acetyl-PAT were isolated and their chemical structures elucidated by (1)H and (13)C NMR, IR, and UV spectroscopy.

The mycotoxin patulin induces intra- and intermolecular protein crosslinks in vitro involving cysteine, lysine, and histidine side chains, and alpha-amino groups.

As previous studies have indicated a multiple electrophilic reactivity of patulin (PAT) towards simple thiol nucleophiles, we have methodically investigated the ability of PAT to covalently crosslink proteins in vitro. By means of sodium dodecylsulphate polyacrylamide gel electrophoresis, the formation of PAT-induced intermolecular protein-protein crosslinks was clearly demonstrated for bovine serum albumin containing one thiol group per molecule, but also for the thiol-free hen egg lysozyme. Characterization of the crosslink sites was carried out by (1) modulation of the thiol groups with N-ethylimaleimide and 2-iminothiolane; (2) comparison with various known crosslinking agents, i.

Reconstruction of glucose uptake and phosphorylation in a glucose-negative mutant of Escherichia coli by using Zymomonas mobilis genes encoding the glucose facilitator protein and glucokinase.

Expression of the Zymomonas mobilis glf (glucose facilitator protein) and glk (glucokinase) genes in Escherichia coli ZSC113 (glucose negative) provided a new functional pathway for glucose uptake and phosphorylation. Both genes were essential for the restoration of growth in glucose minimal medium and for acid production on glucose-MacConkey agar plates.

The Entner-Doudoroff pathway in Escherichia coli is induced for oxidative glucose metabolism via pyrroloquinoline quinone-dependent glucose dehydrogenase.

The Entner-Doudoroff pathway was shown to be induced for oxidative glucose metabolism when Escherichia coli was provided with the periplasmic glucose dehydrogenase cofactor pyrroloquinoline quinone (PQQ). Induction of the Entner-Doudoroff pathway by glucose plus PQQ was established both genetically and biochemically and was shown to occur in glucose transport mutants, as well as in wild-type E. coli.

Molecular characterization of the Entner-Doudoroff pathway in Escherichia coli: sequence analysis and localization of promoters for the edd-eda operon.

The nucleotide sequence of the entire Escherichia coli edd-eda region that encodes the enzymes of the Entner-Doudoroff pathway was determined. The edd structural gene begins 236 bases downstream of zwf. The eda structural gene begins 34 bases downstream of edd.

Cloning, characterization and expression of the Zymononas mobilis eda gene that encodes 2-keto-3-deoxy-6-phosphogluconate aldolase of the Entner-Doudoroff pathway.

The eda gene that encodes 2-keto-3-deoxy-6-phosphogluconate aldolase of the Entner-Doudoroff pathway was cloned from Zymomonas mobilis by genetic complementation of an Escherichia coli mutant. The gene is present in a single copy on the Z. mobilis genome and is not tightly linked to the edd gene.

Predictive value of serum procollagen-III-peptide for the survival of patients with cirrhosis.

The value of the aminoterminal procollagen-III-peptide (P-III-P) in predicting death or survival was evaluated in a group of 43 patients with proven postnecrotic or alcoholic cirrhosis. Patients were followed-up prospectively for 2 years. The prognostic value of P-III-P was compared with the Child classification, fasting and postprandial serum bile acids, and standard laboratory tests such as bilirubin, prothrombin index, pseudocholinesterase, albumin, GOT, GPT, gamma-GT, and clinical findings such as ascites, encephalopathy (assessed with the number connection test = NCT), and nutritional status.

Specific transport of inorganic phosphate, 3-phosphoglycerate and triosephosphates across the inner membrane of the envelope in spinach chloroplasts.

The uptake of phosphate and phosphorylated compounds into the chloroplast stroma has been studied by silicone layer filtering centrifugation. 1. Inorganic phosphate, 3-phosphoglycerate, dihydroxyacetone phosphate and glyceraldehyde phosphate are transported across the envelope leading to an accumulation in the chloroplast stroma.