Physicochemical, Molecular-Orbital and Electronic Properties of Acephate and Methamidophos

Singh, Ashok K.; White, Tom; Spassova, Dina; Jiang, Yin

doi:10.1016/s0742-8413(98)00002-4

Cited by 28 publications

(40 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Methamidophos was hydrolyzed, and it released the CH 3 S group at pH 11.0. 28) The results indicate that the recovery of methamidophos was above 95%, with pH values from 7.4 to 10.2. Hence the subsequent analyzes were all performed at pH 8.0, at which the analyte still remained stable and recovery was above 95%.…”

Section: Optimization the Mispe Conditionsmentioning

confidence: 89%

“…28) Hence the effects of the sample pH on the loading and extraction process were investigated using phosphate buffer (0.05 M) between pH 6.0 and 11.0, and by processing in the MISPE system 1.0 mL of 1.0 mg/mL the methamidophos. The lower recovery at lower pH 6.8, indicating methamidophos breakthrough during the loading stage, can be explained by protonation of the methamidophos molecules.…”

Section: Optimization the Mispe Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

Selective Solid-Phase Extraction Using Molecularly Imprinted Polymer for Analysis of Methamidophos in Water and Soil Samples

Shen

Yuan

et al. 2011

Bioscience, Biotechnology, and Biochemistry

View full text Add to dashboard Cite

Section: Optimization the Mispe Conditionsmentioning

confidence: 89%

Section: Optimization the Mispe Conditionsmentioning

confidence: 99%

Selective Solid-Phase Extraction Using Molecularly Imprinted Polymer for Analysis of Methamidophos in Water and Soil Samples

Shen

Yuan

et al. 2011

Bioscience, Biotechnology, and Biochemistry

View full text Add to dashboard Cite

“…This phenomenon is mainly noticeable at pH 9. According to several authors , Simões et al 2006, Singh et al 1998, Walsh et al 1999a, OPA promotes protein cross-linking by reacting with thiols, primary amines and nucleophilic centers of amino acids. In fact, it is known that BSA contains glycine, which can react with OPA, neutralizing it (Rutala et al 2001).…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial mechanisms of ortho ‐phthalaldehyde action

Simões

Cleto

et al. 2007

J. Basic Microbiol.

View full text Add to dashboard Cite

Biocides generally have multiple biochemical targets. Such a feature easily entangles the analysis of the mechanisms of antimicrobial action. In this study, the action of the dialdehyde biocide ortho-phtalaldehyde (OPA), on bacteria, was investigated using the Gram-negative Pseudomonas fluorescens. The targets of the biocide action were studied using different bacterial physiological indices. The respiratory activity, membrane permeabilization, physico-chemical characterization of the bacterial surfaces, outer membrane proteins (OMP) expression, concomitant influence of pH, contact time and presence of bovine serum albumin (BSA) on respiratory activity, morphological changes and OPA-DNA interactions were assessed for different OPA concentrations. With the process conditions used, the minimum inhibitory concentration was 1500 mg/l, the concentration to promote total loss of bacterial culturability was 65 mg/l and the concentration needed to inactivate respiratory activity was 80 mg/l. These data are evidence that culturability and respiratory activity were markedly affected by the biocide. OPA lead, moreover, to a significant change in cell surface hydrophobicity and induced propidium iodide uptake. Such results suggest cytoplasmic membrane damage, although no release of ATP was detected. At pH 5, the bactericidal action of OPA was stronger, though not influenced by BSA presence. Nevertheless, at pH 9, BSA noticeably (p < 0.05) impaired biocide action. A time-dependent effect in OPA action was evident when contemplating respiratory activity variation, mainly for the lower exposure times. Scanning electron microscopy allowed to detect bacterial morphological changes, translated on cellular elongation, for OPA concentrations higher than 100 mg/l. Interferences at DNA level were, however, restricted to extreme biocide concentrations. The overall bactericidal events occurred without detectable OMP expression changes. In conclusion, the results indicated a sequence of events responsible for the antimicrobial action of OPA: it binds to membrane receptors due to cross-linkage; impairs the membrane functions allowing the biocide to enter through the permeabilized membrane; it interacts with intracellular reactive molecules, such as RNA, compromising the growth cycle of the cells and, at last, with DNA.

show abstract

“…Then the enzyme activity was determined using ATCh as the substrate [14], (final ATCh conc. during enzyme assay ¼ 0.5 mM).…”

Section: In Vitro Evaluation Of Acetylcholinesterase Inhibitionmentioning

confidence: 99%

Synthesis, lipophilicity study and in vitro evaluation of some rodenticides as acetylcholinesterase reversible inhibitors

Ghadimi

Mousavi

Javani

2008

Journal of Enzyme Inhibition and Medicinal Chemistry

View full text Add to dashboard Cite

The anti-AChE activity of phosphoramidates has been noticed for many years. Because of the wide application of phosphoramidates in recent years, there has been a continuing research for synthesis, purification and identification of effective and safe derivatives. In this study some rodenticides with the general formula Me 2 NP(O)( p-OC 6 H 4 -X) 2 , where X ¼ H, CH 3 , Cl, have been synthesized in water (without organic solvent) and characterized by 31 P, 31 P { 1 H}, 13 C and 1 H NMR spectroscopy. Since lipophilicity has been recognized for its importance in QSAR studies, efforts have been made to determine the logP values. The ability of these rodenticides to inhibit human acetylcholinesterase (hAChE) has been predicted with PASS (Prediction of Activity Spectra for Substances) software (version 1.917) and then has been evaluated by a modified Ellman's assay and spectrophotometric measurements.

show abstract

Physicochemical, Molecular-Orbital and Electronic Properties of Acephate and Methamidophos

Cited by 28 publications

References 28 publications

Selective Solid-Phase Extraction Using Molecularly Imprinted Polymer for Analysis of Methamidophos in Water and Soil Samples

Selective Solid-Phase Extraction Using Molecularly Imprinted Polymer for Analysis of Methamidophos in Water and Soil Samples

Antimicrobial mechanisms of ortho ‐phthalaldehyde action

Synthesis, lipophilicity study and in vitro evaluation of some rodenticides as acetylcholinesterase reversible inhibitors

Contact Info

Product

Resources

About