bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of 1, 3‐dichloropropene in dilute aqueous solution
Authors: McCall Philip J. 
Published: November 2006

AbstractHydrolysis of [14C]‐radiolabeled 1, 3‐dichloropropene (1, 3‐D) was studied at pH 5, 7 and 9 at 10, 20 and 30°C in sterile buffered water. The rate of hydrolysis was independent of pH at each temperature, with measured half‐lives of 3‐1 (±0.l), 11.3 (±0.5) and 51 (±2.3) days at 30, 20 and 10°C, respectively. The activation energy for the hydrolysis reaction was determined to be 23.9 kcal mol−1 deg−1. One hydrolysis product was formed during the course of the study and was identified by co‐chrornatography with analytical standards, using h.p.l.c., to be 3‐chloroallyl alcohol. The alcohol appeared to be stable to further hydrolytic conversion and was formed in the same cis: trans ratio as in the initial 1, 3‐D starting material, indicating essentially identical rates of hydrolysis for the cis and trans isomers of 1, 3‐D.
Factors affecting the foliar absorption and redistribution of pesticides. 1. Properties of leaf surfaces and their interactions with spray droplets
Authors: Stevens Peter J. G. , Baker Edward A. 
Published: November 2006

AbstractFoliar uptake into eleven plant species, grown under controlled environment, has been determined for spray deposits of glyphosate, 2, 4‐D and prochloraz applied as solutions in aqueous solvents in the presence and absence of an ethoxylated nonylphenol surfactant. Over 24 h, uptake of glyphosate did not exceed 6% of applied chemical into any species whereas uptake of 2, 4‐D and prochloraz differed between species and was modified significantly by the addition of surfactant. Uptake of prochloraz was increased consistently by adding surfactant, but the response of 2, 4‐D was variable. Increased uptake was attributed mainly to surfactant‐enhanced wetting of the leaf surfaces. Uptake of prochloraz per unit wetted area increased in the presence of surfactant but that of 2, 4‐D decreased. Uptake of either chemical did not correlate with the presence of specialised leaf surface structures, cuticular morphology or distribution of the chemicals within the dried deposits. The dried chemicals were distributed either uniformly or as annuli as a result of complex interactions between the active ingredient, surfactant and the leaf surfaces. Regression analysis indicated that the epicuticular wax and cuticular membrane were the major sinks for both 2, 4‐D and prochloraz during the 24‐h period.
Fumigant residues in wheat and other cereal grains resulting from the use of 1,1,1‐trichloroethane and bromomethane as a liquid fumigant mixture
Authors: Scudamore Keith A. 
Published: November 2006

AbstractThe sorption of 1,1,1‐trichloroethane on wheat, barley and oats during fumigation and its subsequent loss during airing has been studied after treatment with 1,1,1‐trichloroethane alone or in a mixture with bromomethane. The extent of sorption of bromomethane and the amount of inorganic bromide formed from reaction of bromomethane with constituents of the grain samples were not affected by the presence of 1,1,1‐trichloroethane. The sorption of 1,1,1‐trichloroethane on cereal grains and the amount of inorganic bromide formed increased with commodity moisture content. Bromide formation also increased with temperature and varied both with the cereal and with different varieties of wheat tested. At low dosage levels, residues of 1,1,1‐trichloroethane were proportional to concentration times; time (CT product) but at the highest dosage used residues were disproportionately higher than expected, owing to vapour concentration approaching saturation pressure. The rate of loss of 1,1,1‐trichloroethane from wheat, barley and oats under controlled conditions was found to be more dependent on the storage time than on the residue remaining or the original level of treatment. For wheat, initial sorption of 1,1,1‐trichloroethane varied with variety and to a lesser extent also varied between different samples of a single variety tested. However, the rate of airing appeared to be similar for all samples of wheat tested. Results are also described showing the effects on airing rates induced in wheat in which the moisture content was also changing. These results suggest that, in wheat in which moisture content increases during storage, the residue at a specific time after treatment would not be particularly dependent on the interim conditions while in wheat of falling moisture content, residues would very much depend on the conditions prevailing. A knowledge of these effects should help to refine attempts to extrapolate results of laboratory studies to commercial scale treatments.
Excretion, distribution and depletion of [14C]cypermethrin and cis and trans isomers of 3‐(2,2‐dichlorovinyl)‐2,2‐dimethylcyclopropanecarboxylic acid administered orally to laying hens
Authors: Akhtar M. Humayoun , Hamilton Robert M. G. , Trenholm H. Locksley 
Published: November 2006

AbstractRadiolabelled racemic cypermethrin, and the cis and trans isomers of 3‐(2,2‐dichlorovinyl)‐2,2‐dimethylcyclopropanecarboxylic acid (labelled at C‐1 of the cyclopropane ring) were each separately administered orally in feed for three consecutive days to White Leghorn laying hens. The amount of individual compound dosed was approximately 7.5 mg per hen per day. Radiocarbon was eliminated very rapidly in excreta. Tissue residues were generally very low with the exception of fat depots, but trace amounts of radiocarbon residues were still detectable in fat, liver and kidney 11 days post‐treatment. Residues were detected in the egg albumen of hens treated with cypermethrin and cis isomer of the acid, but none was detected from trans acid. Metabolites identified included products arising from the hydrolysis of the ester bond of cypermethrin, followed by oxidative attack on one or both methyl groups. The rate of oxidative attack on methyl groups was influenced by the geometry of the dichlorovinyl group. On the basis of the metabolites identified a metabolic pathway for cypermethrin in laying hens was proposed which included hydrolysis of the ester bond followed by oxidation of methyl group(s). The data indicate that use of cypermethrin as recommended should not produce residues in eggs and meat of laying hens at levels that are of toxic concern.
Studies on pesticides based on coumarin. I. Antifungal activity of 6‐alkyl‐3‐n‐butyl‐7‐hydroxy‐4‐methylcoumarins
Authors: Singh Rajvir , Gupta Bharat B. , Malik Om P. , Kataria Hans R. 
Published: November 2006

AbstractSeven 6‐alkyl‐3‐n‐butyl‐7‐hydroxy‐4‐methylcoumarins and three other related substituted coumarins were synthesised, characterised and tested for their toxicity towards mycelial growth of seven phytopathogenic fungi in culture. Rhizoctonia solani, Alternaria alternate, and Drechslera oryzae exhibited maximum sensitivity to these compounds whereas Pythium aphanidermatum, Colletotrichum falcatum, Fusarium solani and Macro‐phomina phaseolina were less sensitive. The 6‐n‐butyl and 6‐n‐pentyl derivatives possessed strongest toxicity towards all fungi except C. falcatum but the corresponding 6‐n‐propyl derivative was inhibitory to only D. oryzae and A. alternata.
A study of the trans‐esterification products of malathion by capillary gas chromatography‐mass spectrometry
Authors: Wilkins John P. G. , Mason David J. 
Published: November 2006

AbstractThe organophosphorus insecticide malathion undergoes trans‐esterification reactions with many simple alcohols under mild conditions. The products of a series of such reactions were prepared and characterised by capillary gas chromatography‐mass spectrometry. For the trans‐esterification reaction of malathion with a given alcohol, the mass spectra of the two initial products indicated that they were formed by exchange of one or other of the two non‐equivalent ethoxy groups of the succinate moiety of the malathion molecule. The mass spectra were not sufficiently diagnostic to allow the site of trans‐esterification for each product to be assigned. Synthesis and13 C‐nuclear magnetic resonance spectroscopy were used to show that the major initial product is formed by trans‐esterification of the β‐carboxylate group of the succinate moiety. The two methoxy groups of the phosphorodithioate ester moiety exchange much less readily and, in the alcohols examined, such exchange was only apparent with ethanol. Gas chromatographic retention times and mass spectral data for the series of trans‐esterification products examined are presented and discussed. The data and techniques presented provide a means of determining trace amounts of malathion α‐ and β‐monoacids, which are important metabolites of malathion, after their conversion to a suitable ester (the monoacids themselves were not amenable to gas chromatographic analysis under the conditions described).
Factors influencing the selective toxicity of cis‐ and trans‐cypermethrin in rainbow trout, frog, mouse and quail: Biotransformation in liver, plasma, brain and intestine
Authors: Edwards Robert , Millburn Peter , Hutson David H. 
Published: November 2006

AbstractThe biotransformation rates of cis‐ and trans‐cypermethrin, and their routes of metabolism have been studied in subcellular tissue fractions from rainbow trout, frog, mouse and quail to assess the role of detoxification in the selective toxicity of pyrethroid insecticides in these species. The liver was the principal site of biotransformation in mouse and quail, though intestine and plasma (not quail) were also active in hydrolysing cypermethrin isomers. In trout, plasma and intestine were more important sites than liver for the detoxification of tram‐cypermethrin. On the basis of total metabolism of cypermethrin isomers by liver per kilogram of body weight, mouse, quail and frog were respectively 27, 17 and 2 times more active than trout towards the cis‐isomers, and 87, 55 and 6 times more active in metabolising the trans‐isomers. Some of these differences were accounted for by variations in liver/body weight ratios. Extra‐hepatic tissues metabolised cypermethrin principally by ester hydrolysis with maximal activity towards the trans‐isomers, brain and gut contents possessing very low activities. In the presence of NADPH and UDPGA, cis‐ and trans‐cypermethrin were metabolised at very similar rates in frog, mouse and quail liver. Trout liver was more active towards the cis‐isomer forming 4′‐hydroxycypermethrin (aryl hydroxylation) and its glucuronide almost exclusively. Frog and mouse showed either aryl hydroxylation or aliphatic hydroxylation of one of the methyl groups at C‐2 of the cyclopropane ring of cis‐cypermethrin, while quail was unique amongst the four species in metabolising the cis‐isomers largely by oxidative de‐esterification. In all species, except trout, trans‐cypermethrin was rapidly hydrolysed by micro‐somal esterases. The presence of the phase II cofactor UDPGA increased the rate of biotransformation mainly through the glucuronidation of the products of oxidation. This investigation shows that, in addition to differences in target organ sensitivity, biotransformation accounts for some of the observed differences in the susceptibility of these four species to pyrethroids.
Studies on pesticides based on coumarin. II. Synthesis and antifungal activity of ten 2‐alkyl‐7, 8‐dihydro‐3‐hydroxynaphtho[1,2‐c]chromen‐6‐ones
Authors: Gupta Bharat B. , Singh Raj V. , Malik Om P. , Kataria Hans R. 
Published: November 2006

AbstractA series of 2‐alkyl‐7, 8‐dihydro‐3‐hydroxynaphtho[1,2‐c]chromen‐6‐ones was synthesised by the condensation of ethyl 3, 4‐dihydro‐1‐oxonaphthalene‐2‐carboxylate with substituted phenols in the presence of POCl3. The compounds were characterised and tested for their toxicity towards the mycelial growth of seven phytopathogenic fungi in culture. Drechslera oryzae, Rhizoctonia solani and Colletotrichum falcatum exhibited maximum sensitivity to these compounds whereas Macro‐phomina phaseolina, Fusarium solani, Alternaria alternata and Pythium aphanidermatum were less sensitive. 2‐Ethyl‐7, 8‐dihydro‐3‐hydroxy‐naphtho[1,2‐c]chromen‐6‐ones possessed greatest toxicity with EC50 values ranging from 0.2 to 2.5 μg ml−1 against all fungi except A. alternata and P. aphanidermatum.
Photochemical isomerization of fluazifop‐butyl
Authors: Frigerio Alberto , Pusino Alba , Gessa Carlo 
Published: November 2006

AbstractFluazifop‐butyl, butyl (RS)‐2‐[4‐(5‐trifluoromethyl‐2‐pyridyloxy)‐phenoxy]propionate, as a thin film on glass, was photo‐rearranged by ultraviolet irradiation at 254 nm to the isomer, butyl (RS)‐2‐[4‐hydroxy‐3‐(5‐trifluoromethyl‐2‐pyridyl)phenoxy]propionate. The reaction followed first‐order kinetics. A mechanism that accounts for the formation of this product is proposed.
Mechanism of inhibition of sterol biosynthesis enzymes by N‐substituted morpholines
Authors: Taton Maryse , Benveniste Pierre , Rahier Alain 
Published: November 2006

AbstractTridemorph, fenpropimorph and derivatives have been tested in vitro on Δ8→Δ7‐sterol isomerase (SI) from maize seedlings. The results show that these N‐substituted morpholines strongly inhibit this enzyme (I50: 0.4 μM for fenpropimorph, 0.6 μM for tridemorph). In fenpropimorph, where a chiral centre is present at C‐2 of the alkyl chain, good enantioselectivity was observed for enzyme inhibition. Inhibition of SI and of the cycloeucalenol‐obtusifoliol isomerase (COI), another enzyme of plant sterol biosynthesis, is probably due to protonation of the N‐substituted morpholines, giving a positively charged nitrogen atom, at the pH (7.4) of the enzyme assays. In order to test this hypothesis, the pH dependence of the inhibition constants has been measured. Fenpropimorph, (pKa 7.5) which can be protonated to give a morpholinium cation and N‐methylfenpropimorph, the corresponding quaternary ammonium derivative, have been tested as inhibitors in a pH range from 6 to 8.5. The I50 value of fenpropimorph toward the SI increased 20 times as the pH increased from 6 to 8.5. In contrast the I50 value of fenpropimorph for COI did not change significantly in this pH range. While the I50 value of N‐methyl fenpropimorph towards COI decreased more than 50 times as the pH increased from 6 to 8.5, its I50 value for SI only varied slightly in this pH range. Taken together, these results suggest the existence of an interaction of the morpholinium cations with one or several enzyme amino acid residues of a much higher pKa in the case of COI than SI. Moreover for maize COI, the pKa of the amino acid residue(s) interacting with these morpholines derivatives is probably close to that of these molecules.
Interaction of azole derivatives with cytochrome P‐450 isozymes in yeast, fungi, plants and mammalian cells
Authors: Vanden Bossche Hugo , Marichal Patrick , Gorrens Jos , Bellens Danny , Verhoeven Hugo , Coene Marie‐Claire , Lauwers William , Janssen Paul A. J. 
Published: November 2006

AbstractYeast and plant membranes contain rather small amounts of cytochrome P–450 as compared with membrane fractions prepared from bovine adrenal cortex, piglet testis and rabbit liver.The agricultural fungicides azaconazole, penconazole, propiconazole and imazalil showed a much greater affinity for microsomal cytochrome P–450 isozymes of Saccharomyces cerevisiae and Candida albicans (ATCC 28516) than for cytochrome P–450 in microsomal fractions prepared from Jerusalem artichoke tubers, maize shoots, pea seedlings or tulip bulbs and for cytochrome P–450 isozymes in mitochondrial or microsomal fractions from rabbit liver, piglet testis and bovine adrenals. The medicinal azole antifungals miconazole, clotrimazole, ketoconazole, fluconazole and itraconazole also interacted at much lower concentrations with the microsomal cytochrome P–450 isozymes from S. cerevisiae and C. albicans (ATCC‐28516, ATCC 44859, B 34226/1) than with those in mammalian membranes. Itraconazole showed the highest selectivity; bifonazole was much less selective.The microsomal fraction prepared from C. albicans (isolate B 41628) contained cytochrome P–450 isozymes with a lower affinity than the microsomal fractions from other isolates for miconazole, ketoconazole, fluconazole and itraconazole. However, itraconazole showed still high affinity for these cytochrome P–450 isozymes. In animal models this C. albicans isolate was less pathogenic and was shown to be less sensitive to azole antifungals both in vitro and in vivo.Azole antifungals inhibited ergosterol synthesis at nanomolar concentrations whereas almost micromolor concentrations were needed to obtain a similar inhibition of cholesterol or phytosterol synthesis. This inhibition coincided with the accumulation of 14α‐methylsterols such as 14‐methyl‐fecosterol, 14‐methyl‐24‐methylene‐ergosterol, 14‐methyl‐ergosta‐8, 24 (28)‐dien‐3β, 6α‐diol, obtusifoliol, lanosterol and 24‐methylenedihydro‐lanosterol. In 24‐h‐old cultures of C. albicans the 3β, 6α‐diol was the major sterol. It is speculated that by making the 14α‐methylsterols less lipophilic the cells are trying to eliminate these membrane‐disturbing compounds. This suggests that the azole‐induced ergosterol depletion might represent a greater contribution to their fungicidal activity than the accumulation of 14α‐methylsterols.
Inactivation of fenitrothion on stored maize at different moisture contents
Authors: Samson Peter R. , Parker Russell J. , Keating Julie A. 
Published: November 2006

AbstractBiological activity of fenitrothion on stored maize at various moisture contents and at different times after application was measured by biological assay using adults of Tribolium castaneum (Herbst). Inactivation of actual residues over time was then determined after making the necessary allowance for chemical breakdown. At a given moisture content, the inactivation process was substantially completed during the first 6 weeks after application and loss of effectiveness from 6 weeks onwards resulted mainly from chemical breakdown. At a given time after application, residues were less active at higher moisture content (m.c). Differences in activity between moisture contents were apparent within a few hours of application and continued to increase for up to 3 days, with relatively little change thereafter during storage of 24 weeks. Thus after 24 weeks, residues on maize of 18% m.c. had an activity about 20% that of similarly‐aged residues at 10% m.c. and 4% that of freshly‐applied residues at 10% m.c. These results were in general accord with changes in the proportion of the residue which was collected from the kernels by a surface wash with methanol, this readily‐extractable residue presumably representing the insecticide that may be picked up by insects.
Predicted and observed droplet deposition on tsetse flies (Glossina morsitans) following aerosol application from aircraft
Authors: Johnstone Donald R. , Allsopp Reginald , Cooper Jeremy F. , Dobson Hans M. 
Published: November 2006

AbstractA non‐toxic formulation containing fluorescent tracer was dispersed as an aerosol over savannah woodland in stable meteorological conditions, with only light wind, shortly after sunrise. Droplet deposition on wild caught tsetse flies (Glossina morsitans) was measured by means of a fluorescent tracer technique and compared with the deposit levels predicted from rotary sampler measurements using droplet collection efficiency data for samplers and flies derived from a laboratory wind tunnel study. Good correlation was found between the predicted and observed dose. An additional comparison, based only on rotary sampler data, between a typical spray (measured v.m.d. 27 μm) and a spray with smaller drop size (measured v.m.d. 21 μm) suggested that the latter might be significantly more effective as a means of control.
Residue levels of three organophosphorus insecticides in sweet pepper grown in commercial greenhouses
Authors: Al‐Samariee Adnan I. , Shaker Khloud A. M. , Al‐Bassomy Mabrouk A. 
Published: November 2006

AbstractThe degradation rates and residue levels of diazinon, pirimiphos‐methyl and chlorpyrifos in the leaves and fruits of pepper plants grown in commercial greenhouses were studied using g.l.c. Analysis of leaves at intervals following application showed that the initial residue of diazinon was higher than that of the other two insecticides, while its dissipation rate was faster.The dissipation of chlorpyrifos in fruits was faster than diazinon. The maximum residue levels (m.r.l.) of diazinon (0.5 mg kg−;1) and chlorpyrifos (0.1 mg kg−;1) were reached after 13 and 8 days of application respectively.With diazinon and pirimiphos‐methyl, sprayed 3 weeks before inflorescence, very low concentrations of both insecticides were found in fruits, although these compounds have no systemic behaviour.Chlorpyrifos residue level of 0‐2 mg kg −;1 in harvested fruits did not drop below m.r.l. after 11 days holding period.
Plant growth regulating properties of 1‐amino‐1‐methylethylphosphonic acid and its derivatives
Authors: Lejczak Barbara , Kafarski Pawel , Gancarz Roman 
Published: November 2006

AbstractSeventeen derivatives of 1‐amino‐1‐methylethylphosphonic acid were synthesised and evaluated for plant‐growth‐regulating activity using Cucumis sativus and Triticum aestivum. The tested compounds exerted either moderate herbicidal action or stimulated plant growth. The structure‐activity relationships were similar to those observed earlier for the derivatives of 9‐aminofluoren‐9‐ylphosphonic acids (phosphonic analogues of morphactins).
Multiphase photodegradation of quinalphos
Authors: Dureja Prem , Walia Suresh , Mukerjee Sunil K. 
Published: November 2006

AbstractPhotodegradation of the organophosphorous insecticide quinalphos (O, O‐diethyl O‐quinoxalin‐2‐yl phosphorothioate) has been studied. On exposure to natural sunlight, quinalphos was photodegraded with half‐lives of 30 days in distilled water, 20–23 days in tap and rain water and ≤5 days in 2% aqueous acetone. Quinalphos underwent photoisomerisation, oxidation from P=S to the P=O group and de‐esterification. Photoproducts were isolated and characterised by spectroscopic methods. When applied on soil thin‐layer plates quinalphos was promptly dissipated with a half‐life of ≤6 days.
Effects of microbial inhibitors on the degradation rates of metamitron, metazachlor and metribuzin in soil
Authors: Allen Richard , Walker Allan 
Published: November 2006

AbstractRates of carbon dioxide evolution and degradation rates of metamitron, metazachlor and metribuzin were measured in two soils in the presence of three microbial inhibitors. The nonselective microbial inhibitor sodium azide reduced both carbon dioxide evolution and the rate of loss of all three herbicides in both soils, although the reduction in degradation rate of metamitron was small. The antibacterial antibiotic novobiocin enhanced carbon dioxide evolution from both soils but had variable effects on the rates of herbicide degradation. It inhibited degradation of metazachlor and metribuzin, and in one of the soils its effects on metazachlor degradation were similar to those of sodium azide. Novobiocin inhibited degradation of metamitron to a small extent in one soil only. The antifungal antibiotic cycloheximide also enhanced carbon dioxide evolution from both soils. In general, its effects on herbicide degradation were similar to those of novobiocin, although the extent of inhibition was usually less pronounced. The results are discussed in terms of the relative involvement of microorganisms in degradation of the three herbicides.