bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of acephate and its principal metabolite in leaves by gas‐liquid chromatography
Authors: Allender William J. , Major E. John , Cresswell Geoffrey C. 
Published: November 2006

AbstractA semi‐micro method is described for monitoring levels of acephate (O, S‐dimethyl acetylphosphoramidothioate) and its principal metabolite, methamidophos (O, S‐dimethyl phosphoramidothioate) in leaf material derived from treated, hydroponically grown gerberas (Gerbera jamesonii H. Bollus, ex Hook. f.) To minimise injury to the living leaf, analyses were performed on 13‐mm diameter discs punched from the interveinal regions of the lamina. The leaf disc samples were then extracted with ethyl acetate. Clean‐up of extracts was accomplished by passing the filtered leaf extracts through glass mini‐columns containing carbon + filter aid (2 + 5 by mass). Acephate and methamidophos were eluted from the column with methanol and measured simultaneously by programmed temperature gas chromatography using a thermionic specific detector.
Studies on the mode of action of diflufenican in selected crop and weed species: Basis of selectivity of pre‐ and early post‐emergence applications
Authors: Haynes Carla , Kirkwood Ralph C. 
Published: November 2006

AbstractDiflufenican, a pre‐ and early post‐emergence herbicide, was found to be highly active against a wide range of weeds at application rates of 50–250 g ha‐1. Studies on the mode of selectivity with [14C]diflufenican have demonstrated that selectivity between cereal crops and selected weed species is primarily due to differential uptake and indirectly to translocation; ‘depth protection’ appears to be the major reason for selectivity of soil‐applied diflufenican.
Interaction of tetraconazole and its enantiomers with cytochrome P450 from Ustilago maydis
Authors: Carelli Angelina , Farina Gandolfina , Gozzo Franco , Merlini Lucio , Kelly Steven L. 
Published: November 2006

AbstractAzole antifungal agents are known to inhibit 14α‐demethylation during ergosterol biosynthesis which is mediated by a cytochrome P450. Tetraconazole and its enantiomers have been evaluated for their activity in Ustilago maydis sporidial growth inhibition and for their interaction with microsomal P450 isolated from this pathogenic fungus. The methodology developed for isolation of microsomes exhibiting a P450 peak in reduced carbon monoxide difference spectra required the preparation and gentle lysis of protoplasts. Using this fraction, tetraconazole was observed to bind to U. maydis P450 producing a Type II spectrum indicative of coordination between the triazole N‐4 and the haem Fe3+. Carbon monoxide displacement of azole bound to P450 was monitored and was found to reflect the relative activity of the enantiomers when treating cells. The results imply that the activity of the enantiomers is due to their affinity with the target enzyme and that the orientation of the substituents on the chiral carbon is important in binding to the sterol 14α‐demethylase of this phytopathogen.
Comparative studies on acylurea insect growth regulators and neuroactive insecticides for the control of the armyworm Spodoptera exempta walk
Authors: Fisk Tanya , Wright Denis J. 
Published: November 2006

AbstractLeaf‐dip bioassays with commercial pesticide formulations were used throughout this study. Third‐instar larvae of Spodoptera littoralis were bioassayed for comparative purposes. The end‐point mortality against the third‐instar larvae (L3) of two Spodoptera exempta populations (Bangor and Gent) and a S. littoralis population (NRI) was found to occur at 72 h and 120 h for neuroactive compounds (carbamate, organophosphate and pyrethroid insecticides) and acylureas respectively. Overall, the acylureas were found to be more toxic (up to 240‐fold at the LC50 level) than the most active of the neuroactive compounds tested, the pyrethroids. This difference was greatest against S. littoralis, which was markedly less sensitive to the latter compounds. The Gent population of S. exempta was also found to be significantly less sensitive (7‐folt at LC50) to the pyrethroid, lambda‐cyhalothrin, than the Bangor strain. Two of the most toxic neuroactive and non‐neuroactive compounds, the pyrethroid, cypermethrin and the acylurea, teflubenzuron were chosen for further studies with S. exempta (Gent) and S. littoralis. Relatively little difference in the toxicity of teflubenzuron was observed against different larval instars (L2, L3 and L4) of S. exempta when compared with cypermethrin. Choice‐chamber‐experiments on feeding behaviour showed that when L3 larvae of either species were exposed to both treated and untreated leaves. teflubenzuron had no significant effect on larval distribution, the percentage of each leaf disc consumed or larval weight gain when compared with untreated controls. In contrast, a marked dose‐dependent repellent response to cypermethrin‐treated leaves was shown by S. littralis after 6 h. together with corresponding reductions in the percentage of the treated leaf consumed and in larval weight gain. Similarly, when L3 S. exempta were exposed only to pesticidetreated leaves, cypermethrin significantly reduced premoult larval weight gain, whereas tefiubenzuron had no premoult effect. However, following exposure of L3 S. exempta and S. littoralis to teflubenzuron for 48 h prior to moulting, L4 which survived the moult showed reduced weight gain compared with controls, the reduction being more pronounced on maize than on artificial diet. This antifeedant effect increased in proportion to the concentration of teflubenzuron originally administered. The effect of exposure time to teflubenzuron was examined by placing L3 S. exempta and S. littoralis on leaves treated with the approximate LC50 or LC95 dose for 6–48 h. The exposure time required to produce appreciable mortality (relative to LC values) within the treated population was found to be 24 h.
Quantitative structure‐activity relationships of light‐dependent herbicidal 4‐pyridone‐3‐carboxanilides III. 3‐D (comparative molecular field) analysis including light‐dependent diphenyl ether herbicides
Authors: Osabe Hirokazu , Morishima Yasuo , Goto Yukihisa , Fujita Toshio 
Published: November 2006

AbstractUsing a set of representative members selected from 4‐pyridone‐3‐carboxanilides and ortho‐chlorinated diphenyl ethers exhibiting light‐dependent herbicidal activity, we examined the three‐dimensional structure‐activity relationships quantitatively. The most stable conformation of each compound, regarded as the ‘active conformation’, was determined by either semi‐empirical or ab initio molecular orbital calculations. With a hypothesis defining a common substructural skeleton between the two different compound series. each molecule was superimposed. We first analysed the structure‐activity relationship using an index for the substructure shape similarity according to the superimposed conformations. After finding the relevance of the hypothesis, we examined the three‐dimensional structure‐activity relationship using the comparative molecular field analysis procedure. The results suggested that the two different series of compounds have a common region of the receptor site. The variations in the light‐dependent herbicidal potency were governed by hydrophobicty and three‐dimensional steric and electronic field parameters of molecules participating in the transport process and the interaction with the receptor site. The result was consistent with that derived from our previous quantitative analysis with the use of free‐energy‐related substituent parameters and the traditional regression procedure for a large number of pyridone‐carboxanilides.
Acaricidal properties of some synthetic unconjugated allenic anilides
Authors: Bolessa Evon A. , Williams Lawrence A. D. 
Published: November 2006

AbstractSeven unconjugated allenic anilides with the allenic moiety situated at the 3, 4 position were synthesized and evaluated for acaricidal activity against Boophilus microplus (Canestrinii). The order of toxicity (% adult mortality) of the anilides against adult B. microplus at 0.5 μg tick−1 was: N‐(3‐chloro‐4‐methyl‐phenyl)‐5‐methylhexa‐3, 4‐dienamide, (I) = N‐(4‐bromophenyl)‐5‐methylhexa‐3, 4‐dienamide(III)(100%) > N‐(4‐bromophenyl)‐deca‐3, 4‐dienamide (VI)(68%) > N‐(3, 4‐dichlorophenyl)‐5‐methylhexa‐3, 4‐dienamide (II) (32.3%) > N‐(3, 4‐dichlorophenyl)‐5‐methylhepta‐3, 4‐dienamide (IV) (28%) > N‐(3‐chloro‐4‐methylphenyl)‐5‐ethylhepta‐3, 4‐dienamide (VII) (24%) > N‐(4‐bromophenyl)‐5‐methylhepta‐3, 4‐dienamide (V) (20%).Comparison of the relative potencies (in parenthesis) at 1.5 μg tick−1 of the anilides with three commercial acaricides: pyrenone, lindane and carbaryl, revealed the following orders of activities: in comparison with pyrenone: pyrenone = I = II (1) > VI(0.93) > II (0.67) > IV (0.55) > VII (0.46) > VI (0.37); in comparison with lindane: I = HI (6.06) > VI (5.65) > II (4.04) > IV (3.36) > VII (2.76) > V (2.39) > lindane (1.0). All anilides were more toxic than carbaryl which gave no mortality at 1.5 μg tick−1.The need for developing more effective control agents for B. microplus is highlighted by the high levels of resistance found in some Jamaican populations of the pest. Resistance of the orders of 31‐ to 227‐fold had been reported against lindane and between 15‐ and 67‐fold to carbaryl.
Quantitative structure‐activity study of insecticidal 2‐methoxy‐5‐(substituted‐phenyl)‐1, 3, 2‐oxazaphospholidine 2‐sulfides against Musca domestica L. by topical application
Authors: Hirashima Akinori , Yoshii Yutaka , Takeya Ryuko , Eto Morifusa 
Published: November 2006

AbstractThe quantitative relationship between the structure of 2‐methoxy‐5‐(substituted‐phenyl)‐1, 3, 2‐oxazaphospholidine 2‐sulfides (5‐PMOS) and their insecticidal activity against the house fly. Musca domestica L., was analyzed using reported physicochemical parameters and regression analysis. The electronic nature of the substituent on the phenyl group of 5‐PMOS has the most significant effect on the activity, followed by hydrophobic and steric effects; the optimum value of Σρ is zero and the more hydrophobic the substituents on the phenyl group, the higher the insecticidal activity. The plots of observed pLD50, values against calculated pLD50 values for compounds having substituents in the ortho‐position deviated downwards from those of compounds having substituents at the meta and/or para positions. This ortho‐effect, which reduces the insecticidal activity of compounds having substituents at the ortho‐position, was expressed by a dummy parameter D, which has the value 2 for di‐ortho‐substituted derivatives, 1 for mono‐ortho‐substituted derivatives and zero for others. Thus, the highest activity was obtained for 2‐methoxy‐5‐phenyl‐1, 3, 2‐oxazaphospholidine 2‐sulfide, and the activity was decreased by the introduction of any substituents on the phenyl group.
Correlation of protoporphyrinogen oxidase inhibition by O‐phenyl pyrrolidino‐ and piperidino‐carbamates with their herbicidal effects
Authors: Nandihalli Ujjana B. , Sherman Timothy D. , Duke Mary V. , Fisher James D. , Musco Vincent A. , Becerril José M. , Duke Stephen O. 
Published: November 2006

AbstractPhenopylatePhenopylate is not a BSI/ISO‐approved common name.
(2, 4‐dichlorophenyl 1‐pyrrolidinecarboxylate) and 13 of its O‐phenyl pyrrolidino‐ and piperidino‐carbamate analogues were tested for their capacity to inhibit protoporphyrinogen oxidase (Protox), to cause accumulation of protoporphyrin IX (Proto IX), and to cause herbicidal injury. All 14 compounds inhibited Protox of barley etioplast preparations. The I50 values ranged from 21 nM to 4 mM. Highly significant correlations were found between Protox I50 values and herbicidal activity of the more active of the compounds on greenhouse‐grown weeds (pitted morningglory, barnyardgrass, prickly sida, and velvetleaf), pre‐ and/or post‐emergence, and on cucumber cotyledon discs or barley leaf sections in cellular leakage bioassays. Proto IX accumulation in barley leaf sections treated with any of the 14 compounds correlated well with both the I50 values for Protox inhibition and with herbicidal damage to the tissue sections. These data indicate most or all of the herbicidal damage caused by these compounds is due to inhibition of Protox.
Time, concentration and temperature relationships for phosphine activity in tests on diapausing larvae of Ephestia elutella (Hübner) (Lepidoptera: Pyralidae)
Authors: Bell Christopher H. 
Published: November 2006

AbstractThe activity of phosphine against diapausing larvae of Ephestia elutella was shown to depend on several different interactions of duration of exposure, temperature and gas concentration. Using the model proposed by Knight, (CC0) × (tt0) = k, a constant for mortality, the minimum effective concentration C0 was raised and the minimum effective exposure t0 extended as temperatures were increased. The effect of temperature on these thresholds was reduced at higher mortality levels. A range of concentration levels, influenced by temperature, elicited an increase in tolerance at the LD99 level over that evident at higher or lower concentrations. These concentration ranges were 0.9–2‐1 mg litre‐1at 25°C,0.7–2.3 mg litre‐1 at 20°C and 0.1–1.5 mg litre‐1 at 15°C.A mathematical model was fitted to relate concentration and time thresholds, mortality and temperature. At the LD50 level, values for t0 ranged from 2.5 h at 15°C to 5.0 h at 25°C. C0 values increased from about 0.6 to 7.0 μg litre‐1 over this temperature range. At the LD99 level, t0 values ranged from 21 to 28 h and C0 values from 11 to 19 μg litre‐1. Phosphine appeared most effective at each temperature at concentrations from about 40 to 60–100 μg litre‐1.
Determination of chlormequat residues in cotton seed by gas chromatography
Authors: Allender William J. 
Published: November 2006

AbstractA simple and sensitive method to determine chlormequat (chlorocholine chloride) residues in plant tissue has been devised. The technique is based on an in‐vitro multi‐step reaction where chlormequat is initially N‐demethylated with potassium pentafluorothiophenolate followed by a further reaction with excess reagent to produce a pentafluorothiophenyl derivative. Electron capture detection and mass spectrometry were used for quantitative determination and identification. The method was applied to the analysis of cotton seed harvested from cotton plants treated with various concentrations of chlormequat.
Response of Spodoptera exempta (Walk.) larvae to simulated field spray applications of acylurea insect growth regulators with observations on cuticular uptake of acylureas
Authors: Fisk Tanya , Wright Denis J. 
Published: November 2006

AbstractThe acylurea insect growth regulators flufenoxuron (‘Cascade®’) and teflubenzuron (‘Nomolt®’) were applied to maize plants and/or larvae of the armyworm, Spodoptera exempta (Walk.) at volumes equivalent to medium volume (MV; 250 litre ha−1) and ultra‐low volume (ULV; < 1.0 litre ha−1, VMD = 50 μm) sprays at rates ( ≪ 10 g a.i. ha−1) at or below currently recommended field rates. The Egyptian cotton leafworm, S. littoralis was examined for comparative purposes on Chinese cabbage. One‐day‐old third‐instar larvae (L3) of S. exempta sprayed (MV) with either compound (1 and 10 g ha−1), and confined on similarly treated maize leaves for 48 h, showed a high level of response after 48 h (87–100% effective mortality), with 100% mortality after 120 h. Exposure of sprayed L3 to treated plants for 6 h was only slightly less effective. When only larvae were sprayed, the higher rate for both compounds gave 97% mortality after 120 h. The response rate of one‐day‐old L3 S. littoralis was generally slower but was similar to that of S. exempta after 120 h. When plants and larvae were sprayed at relatively low densities (22–45 drops cm−2) with undiluted ULV formulations, L3 S. exempta showed a greater response to flufenoxuron (50 g litre−1) than to teflubenzuron (25 g litre−1) at 48 h but all larvae were effectively dead (93–100% actual mortality) after 120 h. Similar results were obtained with L5 S. exempta. When only larvae were sprayed (23–25 drops cm−2), equivalent concentrations (25 g a.i. litre−1) of diluted flufenoxuron and cypermethrin ULV formulations gave 87 and 90% mortality respectively with L3 S. exempta after 120 h, although the latter compound acted more rapidly. The diluted flufenoxuron was more toxic than its undiluted formulation at similar spray densities. L3 and L5 S. exempta and L3 S. littoralis showed a similar level of response to undiluted flufenoxuron and teflubenzuron. Little or no difference in toxicity was found for topically applied flufenoxuron and teflubenzuron against L3 S. exempta and S. littoralis. Accumulation of [14C]flufenoxuron appeared to increase progressively over 6 h in both species, while that of [14C]teflubenzuron reached a peak after 1 h. After 6 h, there were relatively greater amounts ( > 2‐fold) of radioactivity in flufenoxuron‐treated than in teflubenzuron‐treated larvae. Such differences may account for the greater speed of action observed with the former compound in some experiments. The potential of flufenoxuron and teflubenzuron for the control of S. exempta is discussed with particular regard to the significant contact activity and reasonably rapid response time (effective mortality at 48 h) shown by these compounds at field rates.
Speed of action and toxicity of acylurea insect growth regulators against Spodoptera exempta (Walk.) and Spodoptera littoralis (Boisd.) larvae: Effect of inter‐moult age
Authors: Fisk Tanya , Wright Denis J. 
Published: November 2006

AbstractUltra‐low volume (ULV) spray bioassays at droplet densities (20–80 drops cm−2) corresponding to field deposits were used to determine the efficacy of two acylurea insect growth regulators, teflubenzuron (‘Nomolt®’) and flufenoxuron (‘Cascade®’) against three different age groups of third‐instar Spodoptera exempta and Spodoptera littoralis larvae. While no response (mortality and/or abnormal moulting with impaired ability to feed) was observed with one‐day‐old larvae until 48 h after treatment, two‐day‐old larvae showed some response (27–93% abnormal moulting and 3–10% mortality when larvae were sprayed; 80–100% abnormal moulting and up to 83% mortality when larvae and plants were sprayed) after 24 h and up to 100% mortality at 120 h. Studies with non‐feeding, pre‐moult larvae showed that cuticular uptake of acylureas was sufficient to affect an appreciable proportion of larvae after 24 h, with up to 100% mortality at 120 h. More detailed studies with pre‐moult S. littoralis larvae showed that, while a few larvae which moulted between 1 and 5 h after treatment showed abnormal moulting to the L4 stage, a much larger proportion of larvae which moulted 6–20 h after treatment were affected. Previous studies with S. exempta have shown that different larval instars show similar levels of sensitivity to acylureas. The present work suggests that, while the age distribution within instars has little influence on the end‐point mortality of acylureas, it can profoundly modify the speed of response, the majority of larvae within an instar being effectively controlled at the moult following treatment. The significance of these observations in relation to the crop protection activity of acylureas against field populations of Spodoptera larvae is discussed.
Novel inhibitors of sterol C‐14 demethylase and Δ14 Reductase/Δ8 → Δ7 isomerase for cereal disease control
Authors: Masner Petr , Steel Christopher C. , Furter Rolf , Isenring Hans Peter , Oesterhelt Gottfried , Ziegler Hugo , Zobrist Peter 
Published: November 2006

AbstractThe activity of five experimental fungicides combining structural elements responsible for sterol C‐14 demethylase inhibition and sterol nuclear double‐bond transformations has been investigated by examining sterol accumulation in Ustilago maydis (DC.) Corda, inhibition of sterol‐biosynthesis enzymes in Saccharomyces cerevisiae Meyer using a cell‐free system and protective activity in cereals against Erysiphe graminis DC. and Puccinia coronata Corda. Combining the fenpropidin/fenpropimorph basic structure with a pyridine moiety offered no advantage in fungicidal activity. However, the combination of the pyrifenox structure with a morpholine moiety yielded a compound which was a good inhibitor of C‐14 demethylase and Δ8 → Δ7 isomerase in vitro and gave good cereal protection.
Comparative evaluation of some chitin synthesis inhibitors as insecticides against Colorado beetle Leptinotarsa decemlineata Say
Authors: Malinowski Henryk , Pawinsk Maria 
Published: November 2006

AbstractThe bioactivity of the chitin synthesis inhibitors, chlorfluazuron, hexa‐flumuron, teflubenzuron, triflumuron and GR 572(novaluron) used in commercial or experimental formulations against larvae of Colorado beetle, Leplinotarsa decemlineata Say in laboratory and field experiments was evaluated during 1985–90. All compounds showed high potential for control of the pest. The activity mainly depended on the period of time after treatment. Higher activity was found on younger larvae. A shailow dose‐response relationship was observed for a given larval stage, particularly at the last observation, 15 days after treatment. A single treatment is able to suppress the pest population density below a dangerous level during the whole season. Observations showed that long‐term activity resulted from stomach and contact larvicidal action, reduced egg viability and antifeedant effect.
Weed control and herbicide residues in onion following use of chlorpropham and cyanazine
Authors: Cessna Allan , Benoit Diane Lyse 
Published: November 2006

AbstractA gas chromatographic method, using nitrogen‐phosphorus alkali flame ionization detection, is presented for the determination of residues of chlor‐propham and cyanazine in onion (Allium cepa L.). Recoveries of chlorpropham and cyanazine were 94 (±16)% and 84 (±7)% at the 100μg kg‐1 fortification level, and 97 (±8)% and 88 (±10)%, respectively, at 50μg kg‐1. Analysis of immature (whole plants) and mature (bulbs only) onions grown at four sites following a pre‐emergence application of chlorpropham at 6.0–6.7 kg ha‐1 and a subsequent post‐emergence application of a tank mixture of chlorpropham plus cyanazine at 4.5 and 1.1 kg ha‐1, respectively, resulted in no detectable residues of either herbicide. Weed control efficacy was evaluated for two consecutive years. The treatment demonstrated 88 % and 70 % broad‐leaved weed control 13 and 27 days after application, respectively, at the one site in Quebec.
In‐vitro biological models
Authors: Cotterrell David 
Published: November 2006

AbstractRecent developments in the investigation of membrane flux and partition in in‐vitro membrane systems from human and animal tissues are reviewed with an emphasis on three models: multicellular layers, single isolated cells and sub‐cellular membrane fractions. Mechanisms of permeation through multicellular layers such as epithelia. endothelia and confluent layers of cultured cells by radio‐tracer and electrophysiological techniques are considered. For single cells, erythrocytes form one of the major models, and their use, along with reseated ghosts and membrane vesicles, is considered, particularly with regard to the restoration of physiological levels of membrane permeability in the latter. The use of fluorescent intracellular dyes to measure partition into single identified cells dissociated from tissues is discussed. Methods of measuring flux and partition into subcellular fractions from plasma and organelle membranes are reviewed, in addition to new methods of patch clamping small areas of membrane to investigate permeation through single ion channels.