Responses and residues in sugarbeets, soybeans, and corn irrigated with 2,4,-D or silvex-treated water /

"Agricultural Research Service...in cooperation with College of Agriculture, Washington State University and under contract with Pacific Northwest Laboratories, Battelle Memorial Institute."

Determination of antibiotic an pesticide residues in dairy products; [course manual]

Includes bibliographies.

The Biologic and economic assessment of toxaphene : a report of the toxaphene assessment team to the rebuttable presumption against registration of toxaphene /

"Submitted to the Environmental Protection Agency on September 12, 1977 and November 30, 1978."

Methods for sampling and assessing deposits of insecticidal sprays released over forests /

Issued Nov. 1978.

Pesticides monitoring journal

Mode of access: Internet.

Grasselli spraying and dusting schedule.

Mode of access: Internet.

Pesticide and herbicide residues in sediments and seagrasses from the Great Barrier Reef world heritage area and Queensland coast

Pesticides and herbicides including organochlorine compounds have had extensive current and past application by Queensland's intensive coastal agriculture industry as web as for a wide range of domestic, public health and agricultural purposes in urban areas, The persistent nature of these types of compounds together with possible continued illegal use of banned organochlorine compounds raises the potential for continued long-term chronic exposure to plants and animals of the Great Barrier Reef. Sediment and seagrass samples were collected from 16 intertidal and 25 subtidal sampling sites between Torres Strait and Townsville, near Mackay and Gladstone, and in Hervey and Moreton Bays in 1997 and 1998 and analysed for pesticide and herbicide residues. Low levels of atrazine (0.1-0.3 mug kg(-1)), diuron (0.2-10.1 mug kg(-1)), lindane (0.08-0.19 mug kg(-1)), dieldrin (0.05-0.37 mug kg(-1)), DDT (0.05-0.26 mug kg(-1)), and DDE (0.05-0.26 mug kg(-1)) were detected in sediments and/or seagrasses. Contaminants were mainly detected in samples collected along the high rainfall, tropical coast between Townsville and Port Douglas and in Moreton Bay. Of the contaminants detected, the herbicide diuron is of most concern as the concentrations detected have some potential to impact local seagrass communities, (C) 2000 Elsevier Science Ltd. All rights reserved.

The role of His-134, -147, and -150 residues in subunit assembly, cofactor binding, and catalysis of sheep liver cytosolic serine hydroxymethyltransferase

In an attempt to unravel the role of conserved histidine residues in the structure-function of sheep liver cytosolic serine hydroxymethyltransferase (SHMT), three site-specific mutants (H134N, H147N, and H150N) were constructed and expressed, H134N and H147N SHMTs had K-m values for L-serine, L-allo-threonine and beta-phenylserine similar to that of wild type enzyme, although the k(cat) values were markedly decreased, H134N SHMT was obtained in a dimeric form with only 6% of bound pyridoxal 5'-phosphate (PLP) compared with the wild type enzyme, Increasing concentrations of PLP (up to 500 mu M) enhanced the enzyme activity without changing its oligomeric structure, indicating that His-134 may be involved in dimer-dimer interactions, H147N SHMT was obtained in a tetrameric form but with very little PLP (3%) bound to it, suggesting that this residue was probably involved in cofactor binding, Unlike the wild type enzyme, the cofactor could be easily removed by dialysis from H147N SHMT, and the apoenzyme thus formed was present predominantly in the dimeric form, indicating that PLP binding is at the dimer-dimer interface, H150N SHMT was obtained in a tetrameric form with bound PLP, However, the mutant had very little enzyme activity (<2%). The k(cat)/K-m values for L-serine, L-allo-threonine and beta-phenylserine were 80-, 56-, and SS-fold less compared with wild type enzyme, Unlike the wild type enzyme, it failed to form the characteristic quinonoid intermediate and was unable to carry out the exchange of 2-S proton from glycine in the presence of H-4-folate. However, it could form an external aldimine with serine and glycine, The wild type and the mutant enzyme had similar K-d values for serine and glycine, These results suggest that His-150 may be the base that abstracts the alpha-proton of the substrate, leading to formation of the quinonoid intermediate in the reaction catalyzed by SHMT.

Combined Electron Transfer Dissociation-Collision-Induced Dissociation Fragmentation in the Mass Spectrometric Distinction of Leucine, Isoleucine, and Hydroxyproline Residues in Peptide Natural Products

Distinctions between isobaric residues have been a major challenge in mass spectrometric peptide sequencing. Here, we propose a methodology for distinction among isobaric leucine, isoleucine, and hydroxyproline, a commonly found post-translationally modified amino acid with a nominal mass of 113 Da, through a combined electron transfer dissociation-collision-induced dissociation approach. While the absence of c and z(center dot) ions, corresponding to the Yyy-Xxx (Xxx = Leu, Ile, or Hyp) segment, is indicative of the presence of hydroxyproline, loss of isopropyl (Delta m = 43 Da) or ethyl radicals (Delta m = 29 Da), through collisional activation of z(center dot) radical ions, are characteristic of leucine or isoleucine, respectively. Radical migration processes permit distinctions even in cases where the specific e ions, corresponding to the Yyy-Leu or -Ile segments, are absent or of low intensity. This tandem mass spectrometric (MSn) method has been successfully implemented in a liquid chromatography MSn platform to determine the identity of 23 different isobaric residues from a mixture of five different peptides. The approach is convenient for distinction of isobaric residues from any crude peptide mixture, typically encountered in natural peptide libraries or proteomic analysis.

Polychlorinated Biphenyl DDT And Dieldrin Residues In Grey Seal (Halichoerus-Grypus) Males Females And Mother-Foetus Pairs Sampled At The Farne Islands England During The Breeding-Season

PCB, DDT, DDE, dieldrin and total non-polar organohalogen residues have been determined in the blubber-lipid of grey seals (Halichoerus grypus) sampled during the 1972 breeding season (November) at the Farne Islands off the north eastern coast of England. PCBs were analysed by gas-liquid chromatography linked to a chlorine- and carbon-selective microwave plasma detector and total organohalogen residues were determined by microcoulometry. Total organohalogen residues were negatively correlated with blubber thickness and positively correlated with age in males (aged 1 to 24 y) and females (aged 5 to 38 y). However, the correlation of blubber-lipid residue with age in males depended upon the inclusion of immature (aged < 6 y) animals, and in females reflected only a small residue increment. The mean blubber organohalogen concentration of the males was significantly greater than that of the females. PCB and DDT group residue concentrations were significantly correlated. PCB, DDT, DDE and dieldrin were detected in the liver of mother/foetus pairs demonstrating transplacental movement of these residues. The possibility of the condition of the seals at breeding time influencing residue levels and of these residues influencing the health of the population is discussed.

A surface plasmon resonance biosensor assay for the simultaneous determination of thiamphenicol, florefenicol, florefenicol amine and chloramphenicol residues in shrimps

A rapid and sensitive screening qualitative method using a surface plasmon resonance (SPR) biosensor was developed which can detect of all fenicol antibiotic residues in shrimps from a single sample extract. This method requires ethyl acetate extraction followed by a single wash with isooctane/chlorofonrm. Each sample extract is injected over the surfaces of two biosensor chip flow cells, one surface having the capability to detect florefenicol amine (FF amine), florefenicol (FF), and thiamphenicol (TAP) and the second surface for chloramphenicol (CAP) detection. The estimated detection capabilities (CC beta) were 0. 1, 0.2, 250, and 0.5 ppb for CAP, FF, FF amine, and TAP, respectively. This quick, simple test allowed the detection of CAP residues in shrimps at the minimum required performance limit (MRPL) of 0.1 mu g kg(-1) for this compound and of FF, FF amine, and TAP below their maximum residue limits (MRLs). (c) 2006 Elsevier B.V. All rights reserved.

A Critical Review of Screening Methods for the Detection of Chloramphenicol, Thiamphenicol, and Florfenicol Residues in Foodstuffs

This article gives an extensive overview of the wide range of analytical procedures developed for the detection of amphenicol antibiotic residues (chloramphenicol, thiamphenicol, and florfenicol) in many different types of foodstuffs (milk, meat, eggs, honey, seafood). Screening methods such as microbial inhibition methods, antibody-based immunoassays using conventional and biosensor-based detection systems, and some methods based on alternative recognition systems are described. The relative advantages and disadvantages of these methods are discussed and compared. The current status and future trends and developments in the need for accurate and rapid detection of this group of antimicrobials are also discussed.