bluuebunny/crossref_metadata_2025_split huggingface dataset:
The herbicide binding niche of photosystem II‐a model
Authors: Tietjen Klaus G. , Kluth Joachim F. , Andree Roland , Haug Michael , Lindig Markus , Müller Klaus H. , Wroblowsky Heinz J. , Trebst Achim 
Published: November 2006

AbstractThe QB binding niche of photosystem II is also the binding site for many different herbicides. In order to understand the mode of binding of the herbicides, a 3‐dimensional model of the binding niche was constructed. The model was based upon a comparison of the known structure of the QB binding niche in purple bacteria with sequence and mutant data of the D‐1 protein of photosystem II.Plastoquinone builds up hydrogen bonds to phenylalanine 265 backbone amide nitrogen, to serine 264 hydroxyl, and to histidine 215 delta‐1 nitrogen. In addition to these hydrogen bond donors and acceptors, herbicides can build up hydrogen bonds to backbone carbonyl of alamine 263 and to serine 268 hydroxyl. This is supported by binding data of inhibitors in Chlamydomonas reinhardtii chloroplasts of wild type and of five D‐1 protein mutants (Ser264 Ala, Ala251 Val, Phe255Tyr, Val2191le, Leu275Phe).
Determination of petroleum oil deposits on Citrus sinensis (L.) Osbeck leaves
Authors: Allender William J. , Beattie G. Andrew C. 
Published: November 2006

AbstractOil deposited on citrus leaves when sprayed with oil‐in‐water emulsions was measured by gas‐liquid chromatography of a hexane/acetone/water/ethyl acetate extract of the leaves. To overcome the problem of decreased recoveries with increased time between spraying and extraction, a refluxing step was included in the procedure followed by Florisil clean‐up prior to analysis. Mean oil recoveries of 81% were obtained and, unlike recoveries using published methods, they were independent of time between application and extraction. The method is intended to be used in trials to determine the relationship between spray volume, Chinese wax scale mortality and petroleum oil deposition on citrus leaves sprayed by low‐, medium‐ and high‐volume sprayers.
The metabolism in the rat of the herbicidally active isomer (R)‐ flamprop‐methyl in comparison with the racemic form
Authors: Hutson D. H. , Logan C. J. , Taylor B. 
Published: November 2006

AbstractA single dose (4 mg kg−1) of 14 C‐labelled (R)‐flamprop‐methyl to rat was rapidly metabolised and 90% of the dose was eliminated in urine and faeces within 48 h. Four days after dosing, tissue residues were 0–1 μg equivalents g−1 tissue or much less, with the exception of kidney (0–22 μg g−1). There was a statistically significant sex difference in the routes of elimination; this may be attributed to differences in the biliary elimination of the major metabolite, flamprop acid, or its glucuronide conjugate. The fate of racemic flamprop‐methyl was very similar to that of the (R)‐isomer. The major metabolic routes were hydrolysis of the esters to the corresponding acids, hydroxylation of the benzoyl aromatic rings and conjugation. The flamprop acid derived from the (R)‐flamprop‐methyl was found to be partially converted to the (S)‐form (R:S ratio, 87:13). This reaction is discussed in the context of other such biological racemisations recently reported.
Separation of pesticides, related compounds, polychlorobiphenyls and other pollutants into four groups by silica‐gel microcolumn chromatography (application to surface water analysis)
Authors: Leoni Valerio , Cremisini Carlo , Casuccio Alessandra , Gullotti Antonio 
Published: November 2006

AbstractMulti‐residue analyses of pesticides and related compounds generally require clean‐up procedures for the elimination of interfering substances.An analytical procedure for use in the recovery and determination of pesticides and other pollutants in water samples is described, in which the purification of the extracts is improved by the separation of pesticides into four groups.The separation of pesticides by silica‐gel microcolumn chromatography is explained in detail.
Synthesis and biological activity of 4‐aikoxy‐ and 4‐ω‐aminoalkoxy‐2‐trichloromethylquinolines
Authors: Szabó Zoltán , Enisz János 
Published: November 2006

AbstractA number of new 4‐alkoxy‐ and 4‐ω‐aminoalkoxy‐2‐trichloromethyl‐quinolines were synthesised and tested on insects, weeds and plant pathogens. Many of these compounds showed antifungal activity against different fungal species. Some compounds, IVa, IVb, IVc, Vb, Vc and VI, had interesting effects on Phycomycete fungi.
Fate and short‐term persistence of permethrin insecticide injected in a northern Ontario (Canada) headwater stream
Authors: Sundaram Kanth M. S. 
Published: November 2006

Abstract1·275 dm3 of a l·3g dm−3 aqueous emulsion of permethrin (i.e. 1·658 g permethrin) was applied to the surface of a fast‐flowing stream by manual injection. Water samples were collected from the top 1‐cm layer at different intervals of time at various distances downstream from the site of application. Caged samples of stream detritus, crayfish, brook trout and stonefly nymphs, bottled sediment and potted aquatic plants were placed 280 m from the treatment site, and collected afterwards for residue analysis. The downstream movement of the chemical was not uniform with peak concentrations of about 12 ng ml−1 at 30 m and 0·1 ng ml−1 at 730 m from the treatment site. The peak concentrations (ng g−1) in potted aquatic plants, caged detritus, crayfish and brook trout were about 18, 39, 14 and 11 respectively. The residues were higher than the ambient water concentration (1·67 ng ml−1) and dissipated slowly. The peak concentration in the bottled sediment was 2·75 ng g−1, and the residues were lost rapidly. In contrast, the naturally occurring sediment in a beaver pond showed high residues that persisted for a longer period of time. Permethrin concentrations in invertebrate drift ranged from 9 to 357 ng g−1, depending on the distance from the application site. The study demonstrated that aquatic invertebrates, plants and stream detritus acted as the major sink for the chemical.
Influence of fungicidal control of cucumber and tomato grey mould (Botrytis cinerea) on fruit yield
Authors: Yunis Hisham , Elad Yigal , Mahrer Yitzhak 
Published: November 2006

AbstractThe fungicides tebuconazole, tebuconazole + dichlofluanid, fenethanil, diethofencarb + carbendazim, and vinclozolin combined with chlorothalonil were tested for their ability to control grey mould (Botrytis cinerea Pers. ex Fr.) of cucumber and tomato grey mould in greenhouses under commercial conditions. In winter 1987/88 the number of diseased female fruits of cucumber (Cucumis sativus L.) was reduced by diethofencarb + carbendazim (2·5 mg dm−3 each) by 93% and by tebuconazole (2·5 mg dm−3)(phytotoxic when alone) or tebuconazole (1 mg dm−3) + dichlofluanid (4 mg dm−3) by 54–57%. Vinclozolin (5 mg dm−3) + chlorothalonil (25 mg dm−3) significantly reduced disease incidence on fruits by 40%. Infection foci on cucumber stems were significantly decreased by vinclozolin + chlorothalonil. A more pronounced decrease was obtained with diethofencarb + carbendazim, tebuconazole, or tebuconazole + dichlofluanid. During the season of winter 1988/89, tebuconazole + dichlofluanid (1·5 + 6 and 3 + 12 mg dm−3) and RH7592 (1 mg dm−3) significantly reduced diseased fruits by 30–71%. Grey mould of tomato (Lycopersicon esculentum Mill.) leaves was reduced by more than 90% and on fruits by 78–87% when tebuconazole + dichlofluanid (1·5 + 6 and 3 + 12 mg dm−3) or diethofencarb + carbendazim (2·5 mg dm−3 each) were applied. Yields of cucumber fruits of the common parthenocarpic cv. Kasem 292 were weighed. There was no correlation between disease level and yield in any experiment, plot or date except for two measurements. Compesation in fruit production by the plant may be regarded as the reason for no positive yield response to efficient control. The possibility of reducing fungicide application is discussed. Control of grey mould on tomato resulted in yield increase.
2‐Benzyloxy‐6,8‐Dioxabicyclo[3.2.1]Octanes: New carbohydrate‐derived herbicides
Authors: Blattner Regine , Furneaux Richard H. , Mason Jennifer M. , Tyler Peter C. 
Published: November 2006

AbstractStructure—activity relationships in a new group of ‘cyclic ether’ herbicides have been probed by synthesis and evaluation of a range of isomers and analogues of 1,f‐anhydro‐4‐O‐benzyl‐3‐deoxy‐2‐O‐methyl‐β‐D‐gluco‐pyranose. The absolute and relative stereochemical arrangement of the benzyloxy‐ and methoxy‐groups and the pyran‐ring oxygen atom possessed by this compound were essential for herbicidal activity, but the directionality of the —CH2O— bridge unit was not. The benzyl substituent could be modified, especially by ortho‐substitution on the benzene ring, without significant loss of herbicidal activity, but the azido‐, ethoxy‐ and allyloxy‐groups were the only replacements for the methoxy‐group that did not result in a significant loss of potency. Selectivity for weeds in broad‐leaf crops was enhanced by the introduction of an alkyl or substituted alkyl group at the anomeric carbon.
Allylamine antimycotics: Recent trends in structure—activity relationships and syntheses
Authors: Nussbaumer Peter , Ryder Neil S. , Stütz Anton 
Published: November 2006

AbstractMethods developed for the synthesis of terbinafine‐related allylamine antimycotics are reviewed. The synthesis of the en‐yne side chains were generally accomplished by means of organometallic reactions. The use of Pd0‐catalysed coupling reactions allowed easy access to derivatives bearing sensitive side‐chain substituents. As examples, four metabolites of terbinafine were prepared via this procedure.Investigations with the carbon analogue of terbinafine revealed that, within the allylamine antimycotics, the nitrogen appears to be necessary for penetration by the drug into the fungal cell.Replacement of the naphthalene moiety of terbinafine by optionally substituted benzo[b]thiophenes led to a number of derivatives with high antifungal activity. A series of benzo[b]thienyl compounds with the side chain at position 7 and different substituents at position 3 showed significantly increased activity against Candida albicans in vitro. In particular, the 3‐chloro derivative with the allylamine side chain at position 7(SDZ 87–469) proved to be the most potent allylamine antimycotic reported to this date.Two novel types of lead structures, the homopropargylamines and the benzylamines show very high activity in vitro.
Systemic transport of tritiated phosphonate in tomato plantlets (lycopersicon esculentum mill)
Authors: d'Arcy‐Lameta Agnès , Bompeix Gilbert 
Published: November 2006

AbstractPhosphonate uptake and distribution were evaluated in tomato plantlets by direct determination and by autoradiography. The rate of root uptake was linear during the 2 h of assay, suggesting active transport of the molecule. Phosphonate was readily taken up through the roots and translocated to the leaves, which contained the molecule within 2 min of root application. Autoradiography showed that phosphonate was transferred apoplastically by veins and progressively entered the lamina by symplastic transport. After a root loading of 2 h, plants were transferred to water and phosphonate levels were evaluated over the following 3 days: the concentrations in roots increased with a corresponding decrease in phosphonate levels in the leaves. These experiments demonstrated the ambimobility of phosphonate.
Study of pesticides in waters from a chalk catchment, cambridgeshire
Authors: Clark Lewis , Gomme Joe , Hennings Susan 
Published: November 2006

AbstractWRc are undertaking a long term study of pesticides in the aquatic environment. A study of the pesticides in the rain, river water and groundwater of the Granta catchment in Cambridgeshire is now in its fourth year. Preliminary results are presented and the concentrations of agricultural pesticides in environmental waters are related to the land‐use within the catchment.The Granta study is incomplete but certain anomalies in pesticide occurrence can be identified. In particular, the triazines are much more prevalent in the groundwaters than their agricultural usage would lead one to expect.The limited data base gives problems with modelling the contaminant transport in groundwater. The present situation is reviewed and areas of future work necessary to fulfil the modelling needs identified. These areas of study.The historical land‐use and pesticide usage; the groundwater quality data base; the pesticide transport in the unsaturated zone.
Simultaneous recording of neurophysiological effects and toxicological symptoms of cypermethrin poisoning in intact larvae of Spodoptera littoralis boisd
Authors: Broderick Mark P. , Leake Lucy D. , Ford Martyn G. , Greenwood Richard , Crichton Raymond 
Published: November 2006

AbstractA method is described for simultaneous recording of in‐vivo nerve activity and toxicological symptoms from 6th‐instar larvae of Spodoptera littoralis poisoned with insecticide. Topically applied doses (9 ng‐180 μg insect−1) of cypermethrin induced hyperactivity, repetitive activity and bursting in the ventral nerve cord; these activities were associated with different stages of poisoning in the whole animal and are consistent with pharmacokinetic studies. Nerve activity continued long after the larvae appeared to be dead (i.e. up to 5‐6 days), although microscopic examination of these larvae revealed that they were still capable of small movements. At the lower doses (up to the LD95) time to death was inversely proportional to dose. Death of the organism may be related to the number of neurones which are affected by the insecticide.
Determination of bifenthrin in pumpkins by gas chromatography and mass spectrometry
Authors: Wei Lester Y. 
Published: November 2006

AbstractThe pyrethroid insecticide bifenthrin was used for control of the squash bug Anasa tristis Deg. on pumpkins. An analytical method has been developed for analysis of bifenthrin residues in pumpkins. The maximum bifenthrin residue found was 0·007 mg kg−1. The bifenthrin residue was also examined by combined gas chromatography/mass spectrometry in the electron impact mode with selected ion‐monitoring for detection.
The dissipation of 1,3‐dichloropropene in ditch bottom sediment and associated aerobic ditch water
Authors: Yon Denis A. , Morrison Grant A. , McGibbon Alec S. 
Published: November 2006

AbstractThe aerobic aquatic metabolism of [14C]1,3‐dichloropropene has been studied in two ditch waters and their associated sediments using a modification of the requirements of Section G.2. of the Dutch Registration Guidelines.Preliminary experiments showed that (a) the evaporation of 1,3‐dichloropropene from water had a half‐life of less than 5 h, and (b) in a soil/water slurry, 1,3‐dichloropropene was rapidly converted to 3‐chloropropenoic acid.In the definitive experiment conducted in two sediments, the overall recovery of radioactivity was good (84·5%) given the volatile nature of the chemical. In both sediment types, 1,3‐dichloropropene evaporated rapidly from water. In the Letcombe samples (organic silty clay loam) more radioactivity was associated with the sediment (40%) than ditch water (5%) than in Marcham samples (medium clay, 12% in sediment and 10% in water) and this may reflect the organic matter content of the two sediments (10·5% and 2·9% respectively). The 1,3‐dichloropropene in the ditch water was rapidly converted to 3‐chloropropenoic acid and other minor polar products. The material in the soil was not investigated further.
Deposition, mobility and persistence of sprinkler‐irrigation‐applied chlorpyrifos on corn foliage and in soil
Authors: Don Wauchope R. , Young John R. , Chalfant Richard B. , Marti Luz R. , Sumner Harold R. 
Published: November 2006

AbstractThe insecticide chlorpyrifos (O,O‐diethyl O‐3,5,6‐trichloro‐2‐pyridyl phosphorothioate) was applied to sweet corn (Zea mays L.) by chemigation, injecting either an emulsifiable formulation or technical chlorpyrifos dissolved in soybean oil into 0·25 cm or 1·27 cm sprinkler‐applied irrigation water. Half of the plots treated with chlorpyrifos in 0·25 cm water were immediately irrigated further with 1·27 cm water without chlorpyrifos. Half the plots treated with chlorpyrifos in 1·27 cm water were irrigated with another 1·27 cm water without chlorpyrifos 10 days later. Neither the volume of water used to apply the insecticide nor subsequent irrigation affected chlorpyrifos residues on the corn foliage or in the soil. Chemigation of the soybean oil solution resulted in three times more chlorpyrifos on the foliage than chemigation of the emulsion formulation, apparently because of greater adhesion of the oil droplets to the foliar surface. Chlorpyrifos residues in foliage declined with an initial half‐life of one day. Chlorpyrifos on or near the soil surface declined with an initial half‐life of approximately four days.
The toxicity of mptp (1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine) to Periplaneta americana l. and its effects on dopamine in the cerebral ganglia
Authors: Owen Michael D. 
Published: November 2006

AbstractMPTP (1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine) and MPP+ (1‐methyl‐4‐phenylpyridinium ion) are potent dopaminergic neurotoxins in mammals. The mammalian toxicity of MPTP depends on its conversion, by monoamine oxidase, to MPP+. MPTP is toxic to cockroaches (LD50 720 μg gm−1) and the results suggest that MPTP toxicity depends on monoamine oxidase activity at a site outside the nervous system. MPTP depletes dopamine from cockroach cerebral ganglia and MPP+ inhibits cockroach mitochondrial respiration. While the biochemistry of MPTP toxicity appears to be the same as in mammals it seems that insects are unable to detoxify MPTP before its action has fatal consequences outside the nervous system.
Is sulfotep a proctolin receptor antagonist?
Authors: Wood Sarah J. , Osborne Richard H. 
Published: November 2006

AbstractProctolin‐induced, dose‐dependent (10−8‐2 × 10−6 M) contraction of the isolated foregut of Schistocerca gregaria was antagonised non‐competitively by sulfotep (2 × 10−6‐10−5 M). A higher dose of sulfotep (5 × 10−5 M) caused restoration of the proctolin dose‐response curve to its control value. Neostigmine (10−5 M) caused non‐competitive inhibition of proctolininduced tissue contraction. Increasing the dose of neostigmine to 10−4 M restored the proctolin response to control values. Sulfotep (10−5 M) and neostigmine (10−4 M) caused inhibition of acetylcholinesterase (AChE) activity in tissue homogenates obtained from guts pretreated with either drug for 20 min. The stimulatory effect of sulfotep (5 × 10−5 M) on proctolin‐induced gut contraction was abolished by pretreatment of tissues with atropine (10−6 M). Under these conditions, 5 × 10−5 M sulfotep caused further antagonism of the action of proctolin. The results suggest that sulfotep is a proctolin receptor antagonist in the locust foregut. However, higher concentrations inhibit tissue AChE activity, thereby allowing endogenous acetylcholine to activate muscarinic receptors. This leads to enhanced tissue contractility which masks the antagonistic effect of sulfotep on proctolin‐induced contraction.
Synthesis and mosquito repellent properties of some 2‐alkyl‐N‐acetyloxazolidines
Authors: Taylor Wesley G. , Schreck Carl E. 
Published: November 2006

AbstractTwenty 2,3‐disubstituted oxazolidines, mostly with an alkyl group at C‐2 and an acetyl group at N‐3 have been synthesized and evaluated in the laboratory as mosquito repellents. Repellent activity was assessed in two bioassays with three mosquito species, using a human arm as bait. In patch tests, oxazolidines with an n‐hexyl, n‐heptyl or n‐octyl group showed better activity than those with shorter or longer side chains. In stocking tests, prolonged repellency of selected oxazolidines was evident against Anopheles quadrimaculatus. Some of these experimental chemicals, for example N‐acetyl‐2‐octyl oxazolidine, warrant further investigations as potentially useful insect repellents.
A rapid method for the determination of liquid fumigant residues in food commodities using automated headspace analysis
Authors: Norman Kevin N. T. 
Published: November 2006

AbstractAn automated gas chromatographic headspace method capable of detecting halogenated compounds in cereals, nuts and seeds at levels down to μg kg−1 or less has been developed and evaluated. Commodities were analysed directly without extraction or clean‐up and a simple calibration technique offers a rapid screening quantitative analytical method. Comparison of results obtained using an established solvent extraction method with those obtained using the method described showed good quantitative agreement. Minimum detectable quantities were lower using the headspace method for every fumigant residue/commodity studied. The recommended analytical conditions are suitable for examination of further commodities for the fumigant residues examined and for other volatile halocarbons.
Influence of formulations and adjuvants on the rainfastness of maneb and mancozeb on pea and potato
Authors: Kudsk Per , Mathiassen Solvejg K. , Kirknel Erik 
Published: November 2006

AbstractThe rainfastness of the residual fungicides maneb and mancozeb was assessed on pot‐grown pea (Pisum sativum L) and potato (Solanum tuberosum) plants using a rain simulator. Suspension concentrate formulations were generally retained better than wettable powder formulations. The rainfastness of the fungicides was found to be inversely related to particle size and this partly explained the differences observed between the formulations. Three mm rain applied at a high intensity (27 mm h−1) washed‐off more fungicide than 3 mm applied at a low intensity (3 mm h−1). Addition of various adjuvants significantly improved the rainfastness of the fungicides on both plant species. Oil adjuvants, however, only increased the rainfastness on pea. Furthermore, addition of a latex‐based adjuvant was found to reduce the redistribution of mancozeb on potato leaves.
Mechanisms responsible for propoxur resistance in the german cockroach, Blattella germanica (L.)
Authors: Siegfried Blair D. , Scott Jeffrey G. 
Published: November 2006

AbstractThe mechanisms of propoxur resistance were studied in a strain (Baygon‐R) of the German cockroach (Blattella germanica (L.)) displaying high levels of resistance by topical application compared to a susceptible laboratory strain (CSMA). The penetration of [14C] propoxur was significantly slower in the resistant strain, and resistance was reduced 3.4‐fold when the insecticide was injected compared to topically applied, implicating decreased cuticular penetration as a resistance mechanism. In‐vivo metabolism studies employing [14C]propoxur indicated that propoxur was metabolized at a faster rate in the resistant strain. Resistance to propoxur was partially suppressed by both piperonyl butoxide and S,S,S‐tributyl phosphorotrithioate suggesting the involvement of both cytochrome P450‐dependent mono‐oxygenases and hydrolytic enzymes in the resistance mechanism. In vitro, the Baygon‐R strain displayed higher rates of NADPH‐dependent microsomal metabolism of [14C]propoxur associated with the formation of o‐hydroxy propoxur and N‐hydroxymethyl propoxur, further implicating the monooxygenase system in the resistance. In‐vitro metabolism of [14C]propoxur with cytosolic fractions indicates that the substrate is lost from the incubation mixture at a higher rate in the Baygon‐R strain, possibly due to hydrolytic enzymes that result in production of expired [14C]carbon dioxide. The bimolecular inhibition constants for propoxur against acetyl‐cholinesterase from resistant and susceptible strains were not different. These results indicate that increased levels of metabolism together with decreased rates of penetration are mainly responsible for resistance to propoxur in this strain.