bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interception and persistence of parathion and fenvalerate on cotton plants as a function of application method
Authors: McDowell Leslie L. , Willis Guye H. , Southwick Lloyd M. , Smith Sammie 
Published: November 2006

AbstractParathion (O,O‐diethyl O‐4‐nitrophenyl phosphorothioate) and fenvalerate [(RS)‐α‐cyano‐3‐phenoxybenzyl (RS)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate] were applied by controlled droplet applicators (CDAs) and conventional hydraulic nozzles in refined soybean oil, soybean oil + water, or water, to mature cotton plants (Gossypium hirsutum L.) as ULV (ultra‐low volume, < 5 litre ha−1), VLV(very low volume, 5‐50 litre ha−1), or LV(low volume, 50–200 litre ha−1) carrier rates. The use of CDA or soybean oil applied as ULV and VLV sprays did not produce greater deposition or persistence for either insecticide during the 49‐h test period following application. In general, insecticide persistence was greatest when applied with water or soybean oil + water as LV sprays using the conventional TX8 hydraulic nozzle.
Sorption of lonisable organic compounds by field soils. Part 2: Cations, bases and zwitterions
Authors: Nicholls Peter H. , Evans Avis A. 
Published: November 2006

AbstractSorption of a range of permanent cations, bases and zwitterionic compounds was measured as a function of pH in two soil types. Pyridinium cations were more strongly sorbed (Kd 10– > 1000) than aliphatic cations (Kd < 5). At very low pH, sorption of the aliphatic cations sharply decreased, probably because they are displaced by protons. Most weak bases, including carbendazim andpyridines, were strongly sorbed (Kd 9–35) at low pH, where they would be appreciably protonated, sorption becoming much weaker at soil pH values > 6. However, an additional mechanism of sorption was observed for those zwitterions capable of chelation (e.g. picolinic acid and alanine) which gave rise to high Kd values at pH values near neutral. Inorganic phosphate was strongly sorbed (Kd > 140) save at very low pff. Glyphosate and inorganic phosphate were sorbed very strongly at pH values near to 4 (Kd > 200). The very strong sorption was attributed to ligand exchange interaction. Sorption of picolinic acid was similar when measured in water or calcium chloride solution (0.01 M). However, sorption decreased with increasing concentration of calcium chloride up to 1 M, probably because the protonated form of picolinic acid was displaced by calcium ions.
DDT‐membrane interactions studied with two fluorescent probes
Authors: Antunes‐Madeira Maria Do Carmo , Almeida Leonor M. , Madeira Vitor M. C. 
Published: November 2006

AbstractThe effects of DDT (0‐100 μM) in pure phospholipid and phospholipid/cholesterol bilayers were investigated by fluorescence polarization of 1,6‐diphenyl‐1,3,5‐hexatriene (DPH), a probe located in the bilayer interior, and by excimer to monomer fluorescence intensity ratio (I′/I) of 1,3‐di(l‐pyrenyl)propane (Py(3)Py), a probe sitting closer to the polar region. In the gel phase of dimyristoylphosphatidylcholine (DMPC) bilayers, DDT induces concentration‐dependent fluidizing effects into the hydrophobic membrane regions, but no effects are observed in the outer regions of the membrane, as evaluated by DPH and Py(3)Py, respectively. Furthermore, in the fluid phase of DMPC and for DDT concentrations higher than 10 μM, I′/I of Py(3)Py decreases, reflecting an order increase of the probe environment and DPH fails to detect any apparent effect. Similar effects were observed in other pure lipid bilayers, namely dipalmitoylphosphatidylcholine (DPPC) and distearoylphosphatidylcholine (DSPC). Unlike DPH, Py(3)Py is very sensitive to DPPC and DSPC pre‐transitions which are not abolished by 50 μM DDT. This DDT concentration inhibits to some extent the cholesterol‐induced ordering in DMPC bilayers and high cholesterol concentrations (⩾ 30 mol%) do not prevent insecticide interaction, as evaluated by DPH. On the other hand, the effects of DDT reported by Py(3)Py depend on temperature and cholesterol content of DMPC bilayers. Thus, for cholesterol levels ranging from 10 to 50 mol% and for temperatures below the phase transition temperature of DMPC, Py(3)Py fails to detect any significant effect. Nevertheless, above the phase transition temperature of DMPC, Py(3)Py detects either ordering effects of DDT at low cholesterol contents (< 20 mol%) or fluidizing DDT effects at high cholesterol levels (> 20 mol%).
Mechanisms controlling leaf retention of agricultural spray solutions
Authors: Wirth Wolfgang , Storp Siegfried , Jacobsen Wolfgang 
Published: November 2006

AbstractActive ingredient deposition as a whole during foliar spray application was studied by means of microscopic and macroscopic methods. High‐speed photography of the impact of spray droplets showed that rebound from reflective plant surfaces was reduced only with surfactant concentrations well above the critical micelle concentration. These results correlate with laboratory spraying experiments to determine quantitatively the retention of spray solutions. The dynamic interaction between droplet and foliage seemed to be specifically dependent on surfactant structure, concentration and the distribution of isomers or by‐products in the technical product. Rough surfaces with epicuticular wax crystals were difficult to wet; the orientation of the leaf, however, had little influence on retention. Apolar artificial surfaces retained water rather well and are therefore unsuitable as model surfaces for reflective leaves. Measurement of dynamic surface tension at 100 msec gave a satisfactory correlation with retention values in the case of liquids containing surfactant but failed to predict the good adhesion of polyvinyl alcohol solutions.
Mode of action studies with mefenacet
Authors: Fedtke Carl 
Published: November 2006

AbstractThe unicellular green alga Chlamydomonas reinhardtii was used as a model organism in studies of the mode of action of the oxyacetamide herbicide mefenacet. An algal strain with a decreased sensitivity towards mefenacet was obtained by successively increasing the herbicide concentration in the culture medium from 10 to 50 μM over 9 weeks. Similarly, a second strain was adapted to 10 μM metazachlor and a third one to 20 μM metolachlor. The resistance patterns of these three strains were studied with a selection of herbicides representing different modes of action. In the mefenacet‐ and metolachlor‐adapted strains, clear cross‐resistance was only obtained between the oxyacetamide mefenacet and the chloroacetanilides alachlor, butachlor, metazachlor and metolachlor. The resistance factors (I50 in resistant/I50 in sensitive algae) were between 4 and 50. Little or no resistance was obtained when herbicides with other modes of action were studied (resistance factors between 0.5 and 4). The situation was less clear in the metazachlor‐adapted strain, but here also strong cross‐resistance was seen with other chloroacetanilides and mefenacet (resistance factors between 25 and 40). This strain was, however, significantly cross‐resistant to some herbicides with other modes of action.Investigations of the possible resistance mechanism in the mefenacet‐adapted strain have shown that neither uptake nor metabolism can explain the observed resistance behaviour. The lipid composition and the pattern of soluble amino acids were unchanged. It is concluded that oxyacetamides and chloroacetanilides have the same site of herbicidal action.
Inhibition of acetyl‐coenzyme a carboxylase by the novel grass‐selective herbicide 3‐(2,4‐dichlorophenyl)‐perhydroindolizine‐2,4‐dione
Authors: Babczinski Peter , Fischer Reiner 
Published: November 2006

AbstractThe novel herbicidal compound 3‐(2,4‐dichlorophenyl)‐perhydroindolizine‐2,4‐dione which is active as a pre‐ and post‐emergence grass‐selective herbicide is a new type of inhibitor of plant acetyl‐coenzyme A carboxylase (ACCase; E.C. 6.4.1.2). This has been demonstrated by in‐vitro experiments using isolated corn enzyme. Besides an I50 value of 4.7 μM under the assay conditions used, a mixed‐type inhibitory activity on the enzyme is established. The compound is inactive on rat liver A CCase enzyme and shows decreased activity (pI50 less than 3.0) on the spinach enzyme.
Quantitative structure—activity relationships of light‐dependent herbicidal 4‐pyridone‐3‐carboxanilides I. Effect of benzene ring substituents at the anilide moiety
Authors: Osabe Hirokazu , Morishima Yasuo , Goto Yukihisa , Masamoto Kazuhisa , Nakagawa Yoshiaki , Fujita Toshio 
Published: November 2006

AbstractA number of substituted 4‐pyridone‐3‐carboxanilide derivatives show various degrees of light‐dependent herbicidal activity. The effects of substituents at the anilide moiety on the activity against Echinochloa oryzicola were analysed quantitatively with physicochemical substituent parameters. The activity was shown to vary parabolically with total hydrophobicity (Σπ) of the anilide ring substituents as well as with the steric parameter (Es) of the ortho‐substituents. The Es parameter for only the bulkier ortho‐substituent, with the more negative value, but not for the two, was significant. The effect of substituents at the 1‐position was expressible by indicator variables assigned to each 1‐substituted series, the physicochemical rationalization being left for future analyses.
Effects of metaldehyde and acetaldehyde on specific membrane currents in neurones of the pond snail Lymnaea stagnalis
Authors: Mills Janette D. , McCrohan Catherine R. , Bailey Stuart E. R. 
Published: November 2006

AbstractBath application of metaldehyde or acetaldehyde led to tonic depolarization and bursting activity in identified neurones in the isolated central nervous system of Lymnaea stagnalis. This activity was sometimes accompanied by paroxysmal depolarizing shifts in membrane potential. Those neurones which possessed type 2 action potentials showed marked spike broadening in response to metaldehyde, but little increase in action potential duration in the presence of acetaldehyde. Under voltage clamp, metaldehyde caused a reduction in the delayed rectifier and A‐currents, both of which are outward potassium currents. Acetaldehyde also reduced the delayed rectifier but had no effect on the A‐current. In type 2 neurones, voltage‐dependent calcium current appeared to increase in the presence of metaldehyde, but was decreased by acetaldehyde. The action of metaldehyde and acetaldehyde on firing activity, as well as their differential effects on action potential duration, may be partly explained by alterations in these specific membrane currents.
Diflubenzuron and oogenesis in the codling moth, Cydia pomonella (L.)
Authors: Soltani Noureddine , Soltani‐Mazouni Nadia 
Published: November 2006

AbstractDiflubenzuron, topically applied (0·5 μg insect−‐1) to Cydia pomonella (L.) at pupal ecdysis disturbed growth and development of oocytes. It delayed the adult ecdysis and caused a decrease in both thickness of the follicular epithelium and the size of the basal oocyte during the pupal development. On the other hand, the size of basal oocytes, the protein content per ovary and the number of oocytes per ovary recorded in newly emerged adults were significantly reduced after diflubenzuron treatment.These results, together with observations in several other species, indicate that the reduction in fecundity and egg viability is probably due to interference of diflubenzuron with the vitellogenesis process.
Insect growth regulating activity of 1,5‐disubstituted imidazoles against Bombyx mori and Oncopeltus fasciatus
Authors: Kuwano Eiichi , Hisano Tomomi , Eto Morifusa , Suzuki Koichi , Unnithan Gopalan C. , Bowers William S. 
Published: November 2006

AbstractSeventeen 1,5‐disubstituted imidazoles possessing a variety of substituents were tested on Bombyx mori and Oncopeltus fasciatus. All compounds induced precocious metamorphosis from 4th‐instar larvae of B. mori. Of the compounds tested, 1‐benzyl‐5‐[(E)‐2,6‐dimethyl‐1,5‐heptadienyl]imidazole (KK‐42) was the most active against B. mori larvae. However, none of the compounds induced precocious metamorphosis in O. fasciatus nymphs, although several showed delayed toxicity. Treated nymphs died during or immediately after the moult. A series of 1‐isobutylimidazoles exhibited high activity against O. fasciatus, whereas KK‐42 was inactive even at high doses. There was no apparent correlation between the ability of imidazoles to cause precocious metamorphosis in B. mori and the delayed toxicity for O. fasciatus.
Time‐dependent changes in protein phosphorylation patterns in rat brain synaptosomes caused by deltamethrin
Authors: Kanemoto Yoshiro , Enan Essam E. , Matsumura Fumio , Miyazawa Mitsuo 
Published: November 2006

AbstractEffects of deltamethrin, a powerful pyrethroid insecticide, on the protein phosphorylation and dephosphorylation processes during depolarization in rat brain synaptosomes were studied by using [32P]phosphoric acid as a starting radiotracer and high external concentration of potassium ions or veratridine (10−‐5M) as depolarizing agents. At the onset of depolarization there was a quick rise in phosphorylation in various synaptic proteins for about 15–30 s followed by a gradual decline in levels of phosphorylation. The effect of deltamethrin (10−‐7M) on this system was found to be dependent on the length of preincubation of the synaptosome with the pesticide prior to depolarization. At an early stage (0–3 min preincubation period) it caused a modest suppression of protein phosphorylation activities. When the period of deltamethrin preincubation was extended to 5–20 min, however, it caused a significant increase in protein phosphorylation throughout the depolarization period. At the later stage of the action of deltamethrin (e.g. preincubation period of 30–40 min), deltamethrin‐treated synaptosomes no longer responded to the depolarization signal to raise the level of phosphorylation on many proteins. These results indicate that deltamethrin's actions on the synaptic process are complex. Depending on the length of exposure, its effects on protein phosphorylation responses in intact synaptosomes could be either stimulatory or inhibitory. To study the cause of deltamethrin‐induced synaptic block at the later stage, effects of deltamethrin on protein kinases were studied by using lysed synaptic membranes with [gamma‐32P]ATP. Deltamethrin was shown to inhibit calcium–calmodulin‐dependent protein phosphorylation activities at 10−‐7M when given directly to the enzyme source 10 min prior to the addition of [32P]ATP. Such an observation helps to explain the inhibitory action of deltamethrin on protein phosphorylation which occurs at the late stage of its action (i.e. preincubation time > 20 min).
Insecticide resistance in Helicoverpa armigera in South India
Authors: Armes Nigel J. , Jadhav Deepak R. , Bond Gerald S. , King Andrew B. S. 
Published: November 2006

AbstractCypermethrin, quinalphos, endosulfan and methomyl were bioassayed against strains of Helicoverpa armigera collected from field crops in Andhra Pradesh and Tamil Nadu, South India, during the 1989‐90 and 1990‐91 cropping seasons. In 1989, high levels of resistance to cypermethrin were recorded in strains from cotton in the cotton‐growing regions of Guntur, Andhra Pradesh and Coimbatore, Tamil Nadu, and from pigeon pea near Hyderabad. There was no evidence for resistance to quinalphos or methomyl at that time. In 1990‐91 sampling was more extensive and although tolerance to cypermethrin was lower than the previous season, the survey indicated that pyrethroid‐resistant populations were present throughout much of Andhra Pradesh. Tolerance to quinalphos had increased slightly in 1990‐91, while resistance to methomyl had increased substantially, particularly in the cotton‐growing area of Guntur. Endosulfan tolerance had increased slightly compared to strains tested in 1986‐88 in an earlier study. The geographic and temporal variations in severity of pyrethroid resistance in H. armigera in Andhra Pradesh are believed to arise because of dynamic interactions between local selection pressure and immigration of resistant and susceptible moths at certain times of the year.
Leaching of atrazine into ground water
Authors: Felding Gitte 
Published: November 2006

AbstractA study of the leaching of atrazine from soils in Denmark with high hydraulic conductivity demonstrated only small quantities of the herbicide in the upper ground‐water zone. The atrazine‐treated fields were situated in a region where the water table was high and free lying and where the cover layer consisted of sand. Samples were taken from the upper 1–5 m ground‐water zone at three well‐defined levels. The atrazine content was between 0.01 and 0.05 μg litre−1 the highest concentrations being found at the top of the ground‐water zone.
Negative cross‐resistance to bentazone and pyridate in atrazine‐resistant Amaranthus cruentus and Amaranthus hybridus biotypes
Authors: De Prado Rafael , Sanchez Manuel , Jorrin Jesus , Dominguez Carmen 
Published: November 2006

AbstractPlants of Amaranthus cruentus and Amaranthus hybridus resistant to atrazine and cyanazine were found in maize fields in north‐eastern Spain. Both resistant foiotypes survived doses of 5 kg ha−1 of atrazine and 2–4 kg ha−1 of cyanazine but were controlled by lower doses of bentazone and pyridate than were susceptible biotypes. Such a negative cross‐resistance was not found for chloroacetamides and MCPA. Chlorophyll fluorescence studies revealed that atrazine, bentazone, cyanazine and pyridate (10 mg litre−1) caused inhibition of photosynlhetic electron transport in susceptible leaves, while in resistant plants, atrazine and cyanazine had no effect. Conversely, bentazone and pyridate inhibited photosynthesis to a greater extent in resistant than in susceptible biotypes. Isolated chloroplast membranes from resistant biotypes showed resistance factors of 366 and 501 to atrazine and 39 and 60 to cyanazine for A. hybridus and A. cruentus, respectively. Bentazone and pyridate were found to be more effective in chloropiasts of the resistant biotypes than those of the susceptible plants. It is suggested that enhanced susceptibility to bentazone and pyridate in triazine‐resistant A. cruentus and A. hybridus biotypes may be associated with the alteration of the D‐I polypeptide subunit of photosystem II, as found in triazine‐resistant plants.
Heterotrophic plant cell suspension cultures for monitoring biological activity in agrochemical research. Comparison with screens using algae, germinating seeds and whole plants
Authors: Grossmann Klaus , Berghaus Rainer , Retzlaff Günter 
Published: November 2006

AbstractHeterotrophically cultured cell suspensions are used increasingly in agrochemical research for screening plant‐growth retardants and herbicides which influence plant meristems. For this purpose, a large‐scale microscreen has been devised, which permits the objective monitoring of cell division by measuring the conductivity in cell suspensions cultured in test tubes. Comparing the effects of a wide spectrum of growth retardants and herbicides with different primary modes of action, the test was most sensitive to nitrogen‐geterocyclic retardants in wheat‐cell suspensions and to sulfonylurea > imidazolinone > cyclohexanedione, oxy‐phenoxypropionic acid, nitrile > glufosinate, phenoxy acid, bipyridylium and diphenyl ether herbicides in maize and oilseed rape cell cultures. As had been expected, inhibitors of photosynthetic processes were only slightly active. The results of the tests were compared with the effects of the compounds on germinating seeds of cress (Lepidium sativum L.) and on photoautotrophic systems using algal cell suspensions (Scenedesmus acutus) and duckweeds (Lemna paucicostata). It is suggested that heterotrophic cell suspensions, in combination with the series of biotests mentioned above, are a valuable complement to the whole‐plant screens used routinely in industrial laboratories. They are particularly useful for identifying compounds whose biological activity is masked by limited penetration or translocation behaviour in whole plants.
Pharmacokinetics and in‐vivo Metabolism of Gamma‐Hexachlorocyclohexane in a Susceptible Strain of the Egyptian Cotton Leafworm, Spodoptera littoralis (Boisd.)
Authors: Lagadic Laurent , Dubroca Jacqueline , Echaubard Michel 
Published: November 2006

AbstractThe fate of gamma‐HCH (hexachlorocyclohexane) was studied in a susceptible strain of the Egyptian cotton leafworm, Spodoptera littoralis (Boisd.). A non‐lethal dose (0·2 μg larva−1) was topically applied to fourth‐instar larvae, and the pharmacokinetics of the insecticide were studied for a period of 48 h following treatment. Penetration showed biphasic kinetics, with a rapid increase of the internal gamma‐HCH concentration during the first 6 h after the application, followed by a plateau up to 48 h. The rate of metabolic degradation was highest between 6 and 24 h. During this period, the rapid decrease in the amount of gamma‐HCH in the larvae was associated with an accelerated excretion of metabolites. A compartmental model with curve‐fitting was used to quantify the rates of uptake through the cuticle (penetration) and of loss from the tissues (degradation and elimination). Chromatographic analysis of the aqueous and organic fractions extracted from the larvae and their faeces provided direct evidence that our susceptible strain of S. littoralis was able to metabolise a nonlethal dose of gamma‐HCH.
Substrate‐Dependent Bioavailability of Deltamethrin for the Epigeal Spider Oedothorax apicatus (Blackwall) (Aranaea, Erigonidae)
Authors: Op Akkerhuis Gerard A. J. M. Jagers , Hamers Timo H. M. 
Published: November 2006

AbstractTerrestrial arthropods are mainly exposed to pesticides by uptake from the substrate e.g. “residual” uptake, which depends on the bioavailability of the pesticide. The residual uptake of deltamethrin by female Oedothorax apicatus (Blackwall), a linyphiid spider, was studied in relation to dependence on soil cover, soil moisture, walking behaviour, time after spraying and deposition rate. C14‐labelled deltamethrin was used to quantify the uptake processes. Data were analysed using multiple regression analysis.Uptake was markedly higher from soil covered with fungi or moss than from uncovered soil. From uncovered soils with moisture contents varying from 7 to 49% dry weight, low uptake was measured, while at 63% moisture, the uptake was high. The bioavailability half‐life was 157 min. The rate of uptake decreased with distance walked. The possible consequences of these results for field experiments are discussed.