bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some effects of abamectin on neural activity in larval instars of Spodoptera littoralis boisduval and Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)
Authors: Christie Paul T. , Broderick Mark P. , Wright Denis J. 
Published: November 2006

AbstractThe spontaneous action potential (AP) frequencies recorded from an in‐vivo ventral nerve cord (VNC) preparation of abamectin‐treated insects not showing signs of paralysis (asymptomatic) were significantly (P < 0.05) less than those from untreated insects for fifth‐ and sixth‐instars of Helicoverpa armigera (24 h) and Spodoptera littoralis (24 and 48 h) after topical application of abamectin. There were also significantly (P < 0.05) less APs from abamectin‐treated insects showing signs of paralysis than from asymptomatic abamectin‐treated insects. Significantly (P < 0.05) more radioactivity (and abamectin) was recovered from VNCs of larvae showing signs of poisoning (paralysis) than from asymptomatic‐treated insects. There were also significant (P < 0.001) correlations between the levels of radioactivity (as log dpm) recovered from VNCs and the AP frequency (Hz) after 24 h for both instars and species and after 48 h for S. littoralis. AP frequencies did not decline significantly (P < 0.05) in abamectin‐treated sixth‐ and fifth‐instar S. littoralis larvae until respectively 4 and 8 h after treatment. In conclusion, significant correlations were found in the present study between electrophysiological events in the VNC, visible symptoms of poisoning, and accumulation of abamectin within the VNC. An inverse relationship was found between the levels of abamectin in the VNC and the level of spontaneous nervous activity. These observations are compatible with the VNC being a target site for abamectin. However, the relative importance of the VNC versus peripheral nerves, neuromuscular junctions and muscles as target sites is not known and requires further clarification. No differences in the sensitivity of the VNC to abamectin were found between fifth‐ and sixth‐instar S. littoralis larvae, though there is limited evidence for the H. armigera VNC being less sensitive than the S. littoralis VNC to abamectin.
The HPLC determination of residues of maleic hydrazide in cloves of garlic bulbs following foliar application
Authors: Cessna Allan J. 
Published: November 2006

AbstractA method was developed for the extraction and HPLC analysis of the plant growth regulator maleic hydrazide (MH) from garlic bulbs. Recovery of MH from fortified garlic tissue was 75.8(±6.1)% at the 1 and 2 mg kg−1 fortification levels. MH residues were determined by HPLC in cloves of garlic bulbs following treatment at three sites in southern Ontario with foliar applications at 3.75 kg ha−1. MH residues in the cloves were in the order of 3 mg kg−1 at two sites, and 11 mg kg−1 at the third side.
Actions of imidacloprid and a related nitromethylene on cholinergic receptors of an identified insect motor neurone
Authors: Bai Donglin , Lummis Sarah C. R. , Leicht Wolfgang , Breer Heinz , Sattelle David B. 
Published: November 2006

AbstractNitromethylenes and their analogues are a novel class of insecticidally active molecules of commercial importance. Here we describe the actions of a novel nitroguanidine analogue, l‐(6‐chloro‐3‐pyridylmethyl)‐N‐nitroimidazolidin‐2‐ylideneamine (imidacloprid; NTN 33893) and a nitromethylene, l‐(3‐pyridylmethyl)‐2‐nitromethylene‐imidazolidine (PMNI) on the cockroach fast coxal depressor motor neurone Df and their effectiveness in displacing [125I]α‐bungarotoxin binding to cockroach nerve cord preparations. When tested on the cell body of this identified neurone both imidacloprid and PMNI induce slow depolarizations, which are sensitive to nicotinic receptor antagonists, such as dihydro‐β‐erythroidine (1.0 × 10−5 M) and mecamylamine (1.0 × 10−4 M). Lower concentrations of imidacloprid (1.0 × 10−8 −1.0 × 10−6 M) and PMNI (1.0 × 10−8 M) show no antagonist action on nicotine‐induced depolarization. At concentrations in the range 1.0 × 10−7 −5.0 × 10−7 M, PMNI partially and reversibly blocks nicotine‐induced depolarization. Both compounds are more effective displacers of specific [125I]α‐bungarotoxin binding than nicotine, with imidacloprid (IC50 = 2.0 × 10−7 M) about tenfold more potent than PMNI (IC50 = 1.3 × 10−6 M).
Phenylpyrazoles, a new class of pesticide: Effects on neuromuscular transmission and acetylcholine responses
Authors: Klis Sjaak F. L. , Nijman Nic J. , Vijverberg Henk P. M. , van den Bercken Joep 
Published: November 2006

AbstractPhenylpyrazoles constitute a newly developed class of chemicals with insecticidal and herbicidal properties. In acute toxicity experiments in rats, near‐lethal doses of phenylpyrazoles produce neurotoxic symptoms with an unknown mode of action. We have investigated the effects of two phenylpyrazoles, SLA4722 and SLA4685, in the frog neuromuscular junction and in the clonal muscle cell line BC3H‐1. In the frog neuromuscular junction SLA4722 at concentrations ⩾ 10−5 M caused a pronounced increase in the frequency of miniature endplate potentials (MEPPs). SLA4685 caused a similar increase but was less potent. In the clonal muscle cell line BC3H‐1, SLA4685 produced a concentration‐dependent block of the acetylcholine (ACh) response (IC50 = 2.4(±0.3) × 10−5 M). At 10−6 M a slight potentiating effect of SLA4685 on the ACh response was observed. SLA4722 was less potent in this preparation. The increased transmitter release might, at least partly, be responsible for the excitatory effects of the phenylpyrazoles in intact animals.
Cuticular penetration of foliar‐applied diflufenican in Galium aparine L.
Authors: Knight Heather , Kirkwood Ralph C. 
Published: November 2006

AbstractThe herbicide diflufenican is an effective pre‐emergence compound used for the control of ‘difficult’ dicotyledonous weeds in winter cereals. It is less efficient when applied post‐emergence, activity being found to depend on the dose reaching the apical meristems. Contact with diflufenican had no significant effect on other parts of the plant and translocation was negligible. In the absence of surfactants, the uptake of diflufenican was minimal and complete approximately 2h after treatment. Surfactant incorporation increased the time over which uptake occurred, efficiency depending on surfactant type and lipophilicity. ‘Silwet L‐77’ (1.0 g litre−1) was the only surfactant tested which caused sufficient damage to the apex to prevent subsequent recovery of the plant. The effect of nonylphenol ethoxylate surfactants at concentrations above the critical micelle concentration (<1.0 g litre−1) appeared to be partly attributable to leaf damage caused by the surfactant, possibly facilitating uptake. Increasing leaf coverage by surfactants did not necessarily improve uptake and activity.
Sorption of ionisable organic compounds by field soils. Part 1: Acids
Authors: Nicholls Peter H. , Evans Avis A. 
Published: November 2006

AbstractSorption of different classes of weak organic acids was measured using soils with a range of pH values, taken from long‐term field experiments that had received different amounts of lime. Non‐ionisable compounds were used to demonstrate that the soils of different pH used in the experiments have similar sorptive properties. Values of the sorption coefficients for chloride ion were negative at all pHs except one. Sorption of moderately polar, monobasic, weak acids was weak in acidic soils and very weak in neutral and alkaline soils where they were predominantly dissociated. A lipophilic weak acid was strongly sorbed even at high pH. A model is presented which estimates soil/water distribution coefficients, at any soil pH, from lipophilicity and pKa of the acid and organic matter content of the soil. The model was derived using sorption measured for substituted phenoxyacetic acids. Sorption values calculated using the model were compared with values measured for chlorsulfur on and showed useful agreement. Dibasic acids were strongly sorbed, probably by the mechanism of ligand exchange, if they were chelating agents with potential to form 5‐ or 6‐membered rings with an acceptor atom. Phenylphosphonic acid was strongly sorbed, being a strong monodentate ligand.
Contributions of stomatal infiltration and cuticular penetration to enhancements of foliar uptake by surfactants
Authors: Stevens Peter J. G. , Gaskin Robyn E. , Hong Sung‐Ok , Zabkiewicz Jerzy A. 
Published: November 2006

AbstractRadiolabelled deoxyglucose (DOG) and glyphosate were used to investigate the effects of certain non‐ionic surfactants on the kinetics of foliar uptake in three species. ‘Silwet L‐77’ (5 g litre−1), an organosilicone surfactant, enabled spray solutions to infiltrate stomata, providing uptake of DOG into Vicia bean (50%), oat (35%) and wheat (20%) within 10 min of application. ‘Silwet Y‐12301’, another organosilicone, also induced stomatal infiltration but to a lesser extent; unlike L‐77, this was attenuated by partial stomatal closure. A third organosilicone, ‘Silwet L‐7607’, and two conventional surfactants, ‘Triton X‐45’ (OP5) and ‘Agral 90’ (NP9), did not induce stomatal infiltration. The effective minimum concentration of L‐77 required to enable infiltration of stomata was 2 g litre−1. The uptake of glyphosate into bean did not differ from that of DOG but the ‘Roundup’ formulation of glyphosate partially antagonised the infiltration provided by L‐77. Addition of surfactants did not increase the rate of cuticular penetration of DOG into bean but total uptake was increased, except by NP9, either via infiltration (L‐77 and Y‐12301) or by extending the period during which penetration occurred (L‐7607 and OP5). The surfactants had a variable effect on rates of penetration of DOG into wheat and oat. In general, foliar uptake followed an exponential timecourse which was largely complete within 6 h and only rarely approached 100% of the applied chemical. The stomatal infiltration provided by L‐77 caused an increase in translocation of DOG in bean.
Effects of thuringiensin on European red mite (Acarina: Tetranychidae) mortality, oviposition rate and feeding
Authors: Royalty Reed N. , Hall Franklin R. , Lucius Beth A. 
Published: November 2006

AbstractEffects of two formulations of thuringiensin (ABG‐6162A and ABG‐6266) on mortality, oviposition rate, and feeding of European red mite, Panonychus ulmi (Koch) were evaluated. Mite toxicities of the formulations were not significantly different. Immature instars were significantly more susceptible than adults. Low mortality of all instars was recorded after 3 d, indicating slow activity.The relationship between log (concentration + 1) of ABG‐6162A and ABG‐6266 and P. ulmi oviposition rate was best described by fourth‐order polynomial equations, suggesting that thuringiensin both inhibits and stimulates P. ulmi oviposition. ABG‐6162A affected oviposition at lower concentrations than ABG‐6266.A quadratic relationship was observed between log (concentration + 1) of thuringiensin and P. ulmi adult female feeding. ABG‐6162A reduced feeding more than ABG‐6266 at concentrations ⩾ 1 mg liter−1. Toxicity to immatures and the sublethal effects described suggest that thuringiensin may control field populations of P. ulmi despite low initial mortality.
Molecular mode of action of annonins
Authors: Londershausen Michael , Leicht Wolfgang , Lieb Folker , Moeschler Heinrich , Weiss Hanns 
Published: November 2006

AbstractExtracts of ground seeds from Annona squamosa revealed interesting insecticidal properties. By an activity‐monitored fractionation, different acetogenins, called annonins and annonacin, were determined to be the active components. The investigation of ATP‐levels (at the LT50 value) in Plutella xylostella under treatment with annonin I and antimycin A revealed values of 1.45 and 1.35 μmole g−1 fresh weight respectively, whereas insecticides primarily afecting neurotoxic targets, e.g. cyfluthrin (sodium channels; 2.25 μmole g−1 fresh weight) or parathion (acetylcholinesterase; 2.0 μmole g−1 fresh weight) did not influence the ATP‐levels significantly (control; 1.98 μmole g−1 fresh weight). Further studies on the target site of annonins revealed an inhibitory effect on the NADH‐cytochrome c‐reductase and complex I of insect mitochondria with IC50 values of 4–8 nmole mg−1 protein and 0.8 μM respectively for annonin I. Similar results were observed for the inhibition of complex I from bovine heart muscle (IC50: <0.1 μM) or Neurospora crassa cells (IC50: 0.3 μM), whereas coupling sites II or III were not afected. Furthermore, annonins did not reveal any direct inhibition of oxidative phosphorylation or uncoupling efects.
Prospects for the development of a genetically engineered baculovirus insecticide
Authors: Hawtin Rachael E. , King Linda A. , Possee Robert D. 
Published: November 2006

AbstractBaculoviruses are insect‐specific pathogens which have been employed for the natural control of insect pests for many years. They present an alternative to the use of chemical agents for crop protection. Their restricted host range enables particular pest species to be targeted, and this prevents any loss of beneficial insects from a treated area. However, their large‐scale development as insect control agents has been limited because they take longer to kill the host following infection than rapidly‐acting chemical insecticides. The aim of genetic modification of baculoviruses is to increase their speed of action, while preserving their beneficial characteristics, so creating a fast‐acting, environmentally friendly insecticide. The prospects for achieving this are discussed in this paper, with consideration of scientific progress and the influence of economic and legislative factors.
Quantitative structure—activity relationships of light‐dependent herbicidal 4‐pyridone‐3‐carboxanilide derivatives II. Substituent effects of anilide and pyridone moieties
Authors: Osabe Hirokazu , Morishima Yasuo , Goto Yukihisa , Masamoto Kazuhisa , Nakagawa Yoshiaki , Fujita Toshio 
Published: November 2006

AbstractThe variations in the light‐dependent herbicidal activity against Echinochloa oryzicola of a number of 4‐pyridone‐3‐carboxanilides with various substituents on the anilide and pyridone rings have been examined by use of physicochemical substituent parameters and regression analysis. The effects of substituents of the anilide ring were such that the activity was related parabolically not only with the substituent hydrophobicity (π) but also with the steric bulk parameter (Es) of the bulkier ortho substituent. The effect of substituents at the 1‐position of the pyridone ring was analysed with steric(STERIMOL L and B5) and electronic(γ1) parameters. That of substituents at the 5‐position of the pyridone ring was explained by a parabolic function of a steric (MR) parameter. Analyses of the activity of 105 analogs confirmed that our previous selection of a candidate compound in this series for field trials was indeed appropriate in terms of physicochemical substituent effects.
Residues of the algicide endothal in water, soil and rice, after paddy field applications
Authors: Maini Paolo 
Published: November 2006

AbstractIn order to obtain residue data from the application of the algicide endothal in Italian rice paddy fields, two experiments were carried out using a 50 g kg−1 granular formulation in a small pond and the same granular and two liquid formulations in actual paddy fields of the Italian rice growing area.Endothal decay in the pond water was very rapid, reaching residue levels of 0·01‐1·02 mg litre−1 in two days and 0·004‐0·01 mg litre−1 at the third day. The muddy soil of the pond was free from measurable endothal residues( <0·02 mg kg−1). In the paddy‐field waters, the endothal decay was slower, with an average half‐life time of 3·3 days, independently of the type of formulation. The actual residues in water after 6 days ranged from 0·3 to 1·3 mg litre−1 according to the initial amount of product applied, and, consequently, to the initial concentration in water.Rice samples collected at the normal harvest time from the two paddy fields, treated with three different formulations, showed no endothal residue at the minimum detectable level of 0·01 mg kg−1.
Effects of α‐difluoromethylornithine on photosynthetic oxygen evolution, respiration and polyamine concentrations in detached barley leaves
Authors: Coghlan Steven E. , Walters Dale R. 
Published: November 2006

AbstractDetached barley leaves were treated with the polyamine biosynthesis inhibitor, α‐difluoromethylornithine (DFMO; 1 mM) for either 30 min or 12 h. Exposure to DFMO for 30 min led to a substantial reduction in photosynthesis, expressed either on a unit leaf‐area or unit chlorophyll basis. On the other hand, photosynthesis (expressed on a unit chlorophyll basis) was increased in leaves exposed to DFMO for 12 h, although when expressed on a unit leaf‐area basis, photosynthesis remained unchanged at lower photon flux densities (0‐300 μmol m−2) and was slightly reduced at higher photon flux densities (300‐800 μmol m−2 s−1) s−1). Respiration was unaltered in leaves exposed to DFMO for 30 min or 12 h. Exposure to DFMO for 30 min resulted in significant increases in chlorophyll concentrations, while carotenoid concentrations remained unaltered. However, chlorophyll concentrations were reduced in leaves treated with DFMO for 12 h, although no change in carotenoid concentration was observed. Polyamine concentrations were not significantly affected by exposure of detached barley leaves to DFMO for 24 h.
Isolation and characterisation of two glucosyltransferases from Glycine max associated with bentazone metabolism
Authors: Leah Jon M. , Worrall Timothy L. , Cobb Andrew H. 
Published: November 2006

AbstractTwo glucosyltransferases capable of glucosylating the primary major bentazone metabolite, 6‐hydroxybentazone, have been isolated from tolerant soybean (Glycine max (L.) Fiskerby V) tissue. A soluble flavonol glucosyltransferase, whose primary substrate was kaempferol, was isolated from 3‐week‐old light‐grown tissue. This enzyme had a relative molecular mass of 44 600, a pH optimum of 6·3 and Michaelis constants for kaempferol and 6‐hydroxybentazone of 0·09 and 2·45 mM respectively. A membrane‐bound glucosyltransferase whose primary substrate was the intermediate shikimic acid metabolite, p‐hydroxyphenylpyruvic acid, was also isolated from 7‐day‐old etiolated tissue. This enzyme had a relative molecular mass of 53000 (which could be dissociated to approximately 28000), a pH optimum of 7·5 and Michaelis constants for p‐hydroxyphenylpyruvic acid and 6‐hydroxybentazone of 0·11 and 1·96 mM respectively. These results suggest that 6‐hydroxybentazone, and possibly many other hydroxylated pesticides, may be further detoxified by several glucosyltransferases with overlapping specificity whose primary role involves the storage of endogenous metabolites.
A patch—clamp study of the action of a nitromethylene heterocycle insecticide on cockroach neurones growing in vitro
Authors: Cheung Helen , Clarke Barry S. , Beadle David J. 
Published: November 2006

AbstractThe mode of action of a nitromethylene heterocycle (NMH) insecticide was studied by patch–clamp techniques using cockroach embryonic cultures as an experimental model. Under whole‐cell recordings, this compound elicited inward currents resembling those induced by O‐acetylcholine (ACh). The reversal potentials for both ACh and the NMH were similar, suggesting that the inward currents induced by both were carried by the same species of ion. Pharmacological investigations of NMH‐induced responses revealed that the insecticidal action of this compound is exerted through agonistic action at the nicotinic acetylcholine receptor. Single‐channel studies were also performed to study the interaction of NMH with the nicotinic‐receptor‐coupled ion channel.
Comparison of symptomatic and neurophysiological activities of enantiomers of the insecticide 3‐phenoxybenzyl 1‐(4‐ethoxyphenyl)‐2,2‐dichlorocyclopropane‐1‐carboxylate
Authors: Nishimura Keiichiro , Masutani Hideki , Holan George , Fujita Toshio 
Published: November 2006

AbstractThe insecticidal activities of optical isomers of 3‐phenoxybenzyl 1‐(4‐ethoxyphenyl)‐2,2‐dichlorocyclopropanecarboxylate and related compounds were measured with American cockroaches and their knockdown activities were evaluated with house flies. The activities of the S(−)‐isomer of the dichlorocyclopropanecarboxylate were higher than those of the R(+)‐isomer. The effects of the compounds on the inward membrane currents induced by a stepdepolarizing pulse in crayfish axonal membranes were examined under voltage clamp conditions by the sucrose gap method. The compounds induced a tail current upon step repolarization of the membrane. The tail current decayed to zero in each record, but developed with time after the start of application of the compound until a steady level was reached. The rate of decay of the tail current observed in axonal membranes treated with the S(−)‐isomer was slower than with the R(+)‐isomer. The rates of development of the tail current induced by the two isomers were not very different.
Herbicidal activity of phosphonic and phosphinic acid analogues of glutamic and aspartic acids
Authors: Miliszkiewicz Dorota , Wieczorek Piotr , Lejczak Barbara , Kowalik Ewa , Kafarski Pawel 
Published: November 2006

AbstractPhosphonic and phosphinic acid analogues of glutamic and aspartic acids were synthesized and screened for herbicidal activity on Lepidium sativum L. Depending on the chemical structure, they exhibited significant or moderate herbicidal activity against L. sativum roots (with some representatives being equipotent with phosphinothricin), while their influence on shoot growth was negligible. Cucumis sativus L. appeared to be more tolerant to these analogues. The origin of this selectivity remains to be determined.
Resistance risk assessment of two insect development inhibitors, diflubenzuron and cyromazine, for control of the housefly Musca domestica L. Part II: Effect of selection pressure in laboratory and field populations
Authors: Keiding Johannes , El‐Khodary Ahmed S. , Jespersen Jürgen B. 
Published: November 2006

AbstractLaboratory selection with diflubenzuron (DFB) and cyromazine (CYR) was carried out with strains of houseflies collected on Danish farms. The adult flies were multiresistant to organophosphorus, carbamate and pyrethroid insecticides. Susceptibility to the larvicidal effect of DFB or CYR was monitored on Danish farms where fly control with DFB or CYR had been carried out for one to nine years. On these farms the fly population continued during the winter, but at a low level.Four strains were selected with DFB in seven out of 13–18 laboratory generations. The selections varied from 56% to 94% mortality. The strains showed 1–5 times increase of LC50 and LC95 to DFB. The larvicidal effect of DFB was monitored on five farms where treatment of fly breeding sources in manure (1 g DFB m−2) was carried out regularly for one to nine fly seasons. On none of the farms was any general increase of tolerance to DFB found. Resistance ratios (R/S) compared to the WHO Standard Reference Strain ranged from 0.8 to 2.0 at LC50 and from 1–0 to 2–9 at LC95.Two strains were selected with CYR in five or six out of 13 laboratory generations. The selections varied from 62 to 97% mortality. The strains showed no increase of LC50 or LC95. The larvicidal effect of CYR was monitored on three farms where housefly breeding places in the animal houses were treated with CYR (0.5 g m−2) for two fly seasons. No reduction of susceptibility to CYR was found and the R/S was 0.7 to 0.9.The effect of DFB or CYR selection pressure is compared with other investigations and discussed. Moderate to high resistance to DFB or CYR can develop in housefly populations if the selection pressure is strong, especially when used as feed‐through applications on poultry farms where all feed contains DFB or CYR. If the treatment of fly breeding sources is less complete, resistance problems may not develop.