bluuebunny/crossref_metadata_2025_split huggingface dataset:
Porphyric insecticides. IV: Structure‐activity study of substituted phenanthrolines
Authors: Gut Larry J. , Lee Keywan , Juvik John A. , Rebeiz Carole C. , Bouton Carl E. , Rebeiz Constantin A. 
Published: November 2006

AbstractThe porphyric‐insecticide‐modulating activities of 1,10‐phenanthroline and eight of its analogs were investigated. The insecticidal efficacy of these compounds was closely associated with their ability to enhance the conversion of exogenous δ‐aminolevulinic acid (ALA) to protoporphyrin IX (Proto). As observed for photodynamic herbicidal effects in plants, the presence of nitrogen atoms at positions 1 and 10 of the macrocycle was essential for porphyric insecticidal activity. This was evidenced by the very limited activity of phenanthrene, in which positions 1 and 10 are occupied by carbon instead of nitrogen atoms. On the other hand, enhancement of Proto formation and porphyric insecticidal activity were maintained following methyl, chloro and nitro group substitution at the periphery of 1,10‐phenanthroline. In contrast, Proto levels and photodynamic toxicity were reduced by hydroxy and phenyl substitution at the same positions. Benzyl substitution at the 2–3 and 8–9 positions was also inhibitory. Quantitative structure‐activity calculations suggested a relationship between peripheral group substitution and physicochemical properties of the substituted compounds. Electron density changes in 1,10‐phenanthroline and its analogs that appeared to be related to reduced efficacy included (a) appearance of positive charge‐binding volumes at positions 4 and 7 of the 1,10‐phenanthroline macrocycle, which flanks positive charge‐repelling volumes, (b) a dramatic increase in superdelocalisability (i.e. electron density) over some unoccupied molecular orbitals, and (c) electronic charge at positions 1 and 10 of the macrocycle. Large increases in van der Waals volumes also exerted negative effects on insecticidal efficacy.
Spirosultam LY219048: A new chemical class of insecticide acting upon the GABA receptor/chloride ionophore complex
Authors: Bloomquist Jeffrey R. , Jackson Johnny L. , Karr Laura L. , Ferguson Holly J. , Gajewski Robert P. 
Published: November 2006

AbstractThis study assessed the toxicity and mode of action of a new experimental insecticide, LY219048 in insects and mammals. LY219048 produced rapid convulsions in mice and had LD50 values of 0.7 mg kg−1 and 4 mg kg−1 after intracerebral and intraperitoneal injection, respectively. In initial screens against insects, LY219048 showed low activity against the German cockroach (Blatella germanica L.). Lethality from dietary exposure required one to two weeks, even at concentrations as high as 10000 mg kg−1 (LC50 = 485 mg kg−1). In contrast, it had an LC50 value of 8.3 mg kg−1 against insecticide‐susceptible Drosophila melanogaster (Meig.) when synergized with piperonyl butoxide. Significant resistance to LY219048 (> 12‐fold) was detected in a cyclodiene‐resistant strain of D. melanogaster possessing an altered target site resistance mechanism. This finding suggested that LY219048 blocked the 4‐aminobutyric acid (GABA)‐gated chloride channel in a manner similar to that of the cyclodienes. In physiological studies in larval D. melanogaster central neurons, LY219048 antagonized the reduction of firing caused by 1 mM GABA. Dose‐response experiments showed that the ED50 for blocking inhibition under these conditions was c. 1 μ. Studies of 36CI uptake into bovine brain synaptosomes found that LY219048 was a potent antagonist. At 10 μ it completely blocked chloride flux stimulated by 50 μM GABA. LY219048 competitively displaced [3H]TBOB binding from bovine brain membranes, with an IC50 of 42 nM, which was comparable to values determined for TBPS (35 nM) and picrotoxinin (267 nM). There was little or no displacement (<25%) of [3H]flunitrazepam or [3H]muscimol binding by 10 μM LY219048. Taken together, these results provide strong evidence that this new chemical class of insecticide manifests its acute toxicity by blocking the GABA‐gated chloride channel.
Measurement of evaporation from adjuvant solutions using a volumetric method
Authors: Hall Franklin R. , Kirchner Loren M. , Downer Roger A. 
Published: November 2006

AbstractVarious agricultural spray adjuvants are available which are classified as anti‐evaporants. This quality has the potential to aid in reducing drift and chemical evaporation and so improving coverage. Numerous other adjuvants not claiming these benefits may have these characteristics which are not being exploited. In order to assess these qualities, a simple, rapid assay was devised for measuring relative evaporation rates from individual drops. This method was then used to measure the evaporation rates of a variety of adjuvants under controlled temperature and humidity conditions.The droplet producing device uses a microliter syringe to dispense a droplet of known size. After a given period of time, the drop is taken back into the syringe and the volume lost to evaporation calculated. Modifications to the original device include suspending the drop inside a temperature‐ and humidity‐controlled chamber.The original device was used for determining the rate of evaporation from water drops later than 0.3 mm. We have extended the use of the device to measure the rates of evaporation from a range of adjuvant solutions under controlled temperature and humidity conditions. The data reported here suggest that this method (a) is suitable for measuring evaporation from drops of many (but not all) adjuvant formulations, (b) is capable of discerning differences in relative rates of evaporation and (c) may be used for an array of adjuvant, drop size, and meteorological conditions. Major limitations appear to be (1) equilibrium surface tension, solutions having values less than c.35 mN m −1 are difficult to analyze and (2) a lower limit on drop‐size of c.300 μm.
Removal of paraquat by adsorption on ‘waste’ Fe(III)/Cr(III) hydroxide: Adsorption rates and equilibrium studies
Authors: Namasivayam Chinnaiya , Thamaraiselvi Kaliannan , Yamuna Rangaiya T. 
Published: November 2006

AbstractThe ability of ‘waste’ Fe(III)/Cr(III) hydroxide to adsorb paraquat has been investigated. Effects of contact time, initial concentration and pH, adsorption capacity and desorption have been studied. Adsorption followed a first‐order expression. The adsorption rate constant decreased from 1–84 to 0–50 min−1 with the increase of paraquat concentration from 10 to 40 mg litre−1. Adsorption obeyed the Freundlich isotherm and the K1 value was found to be 0.1995. A maximum removal of 93% was attained at pH 1204. Desorption with water occurred to the extent of 39% indicating that physical sorption was partly responsible in the adsorption process.
Fungicidal activity of three putrescine analogues
Authors: Havis Neil D. , Walters Dale R. , Martin William P. , Cook Fiona M. , Robins David J. 
Published: November 2006

AbstractThe synthetic putrescine analogues (E)‐N,N,N′,N′‐tetraethyl‐l,4‐diaminobut‐2‐ene(E‐TED), the (Z)‐isomer (Z‐TED) and (E)‐N,N‐dimethyl‐1,4‐diaminobut‐2‐ene(E‐DMD) were prepared as their salts, and controlled five important crop pathogens (Erysiphe graminis DC f.sp. hordei Marchal, Uromyces viciae‐fabae (Pers.) Schroet, Botrytis fabae Sardina, Podosphaera leucotricha (Ell. & Ev.) Salm. and Phytophthora infestans (Mont.) De Bary). E‐TED was also effective in vitro, with growth of P. infestans and Pyrenophora avenae Ito & Kuribay completely inhibited at 1800 and 360 mg litre−1 respectively. When P. avence was grown in the presence of 180 mg E‐TED litre−1, there were significant reducuons in putrescine and spermidine concentrations (58% and 35% respectively). An apparent increase in ornithine decarboxylase activity and a decrease in S‐adenosylmethionine decarboxylase activity in P. avenae exposed to E‐TED at 36 mg litre−1 were not statistically significant. Diamine oxidase activity remained unchanged in fungal tissue exposed to E‐TED.
Exploration of glycoprotein structures: Sequences and consequences
Authors: Kent Paul W. 
Published: November 2006

AbstractThe vast expansion in our knowledge of the detailed molecular structure of many glycoproteins has been achieved by purpose‐designed methodologies. In this review, principal experimental methods for gaining fundamental evidence are assessed with respect to well‐known iV‐glycoproteins (e.g. ribonucleases), 0,N‐glycoproteins (e.g. glycophorin A) and O‐glycoproteins (e.g. submaxiilary gland mucins and some sulfated forms). Relevant properties of N‐carbohydrate‐peptide links (N‐acetylglucosaminyl‐asparagine) and O‐linkages (N‐acetylgalac‐tosaminyl‐Thr (or ‐Ser)) are reviewed and the classification and structure of more elaborate glycoproteins is outlined.Key reactions, both chemical and enzymic, effect the cleavage of N‐ and O‐oligosaccharide side‐chains from core protein, and subsequent calibrated chromatographic analysis can permit the identification of certain oligosaccharide groupings characteristic of glycoforms (families of glycoproteins different only in the oligosaccharide chain lengths and bond structures).Basic sequencing of individual oligosaccharides is generally achieved by chemical methods (e.g. methylation analysis, degradation with periodate) and by the action of well‐characterised specific exo‐ and endoglycosidases. Degradation of a glycoprotein chemically (e.g. by cyanogen bromide) or enzymically by endopeptidases to glycopeptides provides means for locating oligosaccharide position(s) on the core protein.The presence of O‐sulfate ester groups on oligosaccharide side‐chains presents further challenging problems for sequencing investigations.Some correlations between oligosaccharide sequences and biological function are considered. While, in the main, the best‐known glycoprotein structures are for those of mammalian origin (e.g. Igs), evidence points to other areas of interest in plants (especially yeasts), invertebrates and micro‐organisms. Allusion is made to current comparative and fundamental physico‐chemical techniques, especially gel permeation chromatography, membrane‐transfer, FAB‐MS and NMR (NOE, COSY, etc.).
The effect of three different pesticides on soil protozoan activity
Authors: Ekelund Flemming , Rønn Regin , Christensen Søren 
Published: November 2006

AbstractThree pesticides, dimethoate, pirimicarb and fenpropimorph, had a negative impact on the colonization of a sterilized soil by a natural population of soil protozoa. Fenpropimorph has an effect at the lowest concentration applied; 25 mg litre−1. Dimethoate reduced the soil respiration significantly for about 10 days after application. In single species cultures of soil protozoa in liquid media, a flagellate Cercomonas sp., was a better test organism than a ciliate, Colpoda sp., or an amoeba, Acanthamoeba sp., with respect to interpretation of dose‐response curves and ease of observation.
Mercury(II) ion‐promoted hydrolysis of some organophosphorus pesticides
Authors: Wan Hai Bin , Wong Ming Keong , Mok Chup Yew 
Published: November 2006

AbstractThe promotion of hydrolysis of some organophosphorus pesticides by mercury(II) ion was studied. The presence of mercuric chloride at 20 mg litre−1 increased the initial hydrolysis rates of malathion, fenitrothion, fenthion and parathion‐methyl in pH 5.5 buffer by two to three orders of magnitude. The hydrolysis was found to be first order with respect to both mercury(II) ion and the pesticide. The main hydrolysis product was 3‐methyl‐4‐nitrophenol for fenitrothion, and 4‐nitrophenol for parathion‐methyl. It is postulated that the reaction involves the formation of a 1:1 complex and a very slow regeneration of the mercury(II) ion from the reacted complex. Mercury(II) ion had little effect on the organophosphorus pesticide dichlorvos.
Behaviour of an alginate‐kaolin based controlled‐release formulation of the herbicide thiobencarb in simulated ecosystems
Authors: Gan Jianying , Hussain Manzoor , Rathor Nasir M. 
Published: November 2006

AbstractAn alginate‐kaolin based controlled‐release formulation of the herbicide thiobencarb, TCR‐1, was prepared. The distribution, bioaccumulation and persistence of thiobencarb from this formulation were compared to those from a commercial granular formulation, 10 G, in flooded paddy soil under controlled conditions and in simulated aquatic systems and rice paddy/fish systems under greenhouse conditions. Persistence of the total residues and thiobencarb parent increased significantly in the soil treated with TCR‐1, and at the end of a 49‐day incubation 32.5% of the applied herbicide was recovered as the parent from the soil treated with TCR‐1, compared to only 15.2% from the soil treated with 10 G. Slower release into water and less accumulation in fish tissues were found in the simulated aquatic system treated with TCR‐1. A lower concentration was detected in the paddy water in the simulated rice paddy/fish system treated with TCR‐1 over the duration of a 66‐day greenhouse experiment. Fish and rice plants accumulated less residues from the system treated with TCR‐1 than from that with commercial formulation 10 G. The overall results indicated that the persistence of thiobencarb in the controlled‐release formulation was prolonged in water and soil, and the potential impact on non‐target components such as rice plants and fish was concurrently reduced.
Dissipation of tralkoxydim herbicide from wheat crop and soil under sub‐tropical conditions
Authors: Srivastava Anjana , Gupta K. C. , Singh Govindra 
Published: November 2006

AbstractThe persistence of tralkoxydim herbicide in wheat crop and in soil was evaluated under Indian sub‐tropical field conditions at two application rates (400 g a.i ha −1 and 800 g a.i ha −1). At 400 g a.i ha −1, tralkoxydim persisted up to 28 days in soil but became non‐detectable only after 45 days in the crop. However, at 800 g a.i ha −1, tralkoxydim residues persisted for 45 days in both soil and crop. The dissipation of the herbicide from both soil and crop appeared to occur in two phases at both rates of application. Each phase followed first‐order kinetics. The values of DT50 and DT90 for both soil and crop are reported.
Characterization of residues in soybeans grown in soil treated with 1,3‐dichloropropene soil fumigant
Authors: Barnekow David E. , Brown Stephen M. , Byrne Sandra L. , Hamburg Arlene W. , Huskin Mike A. , Leisure Andrea M. 
Published: November 2006

AbstractThe metabolism of cis‐ and trans‐1,3‐dichloropropene (1,3‐D) was studied in soybean plants grown in soil treated 24 days prior to planting with [U‐14C]E‐ and Z‐1,3‐dichloropropene at 380 liters ha−1. Isolation and identification of the 14C residue from soybean plants at 84 days (forage) and 176 days (mature) after application showed that no 1,3‐dichloropropene or its putative metabolites, 3‐chloroallyl alcohol and 3‐chloroacrylic acid, could be detected in any of the tissues. The components of the 14C residue included major plant constituents (i.e. fatty acids, protein, pigments, organic acids, sucrose and other carbohydrates, and lignin).
Detection of cyclodiene insecticide resistance‐associated mutations by single‐stranded conformational polymorphism analysis
Authors: Coustau Christine , ffrench‐Constant Richard 
Published: November 2006

AbstractCyclodiene insecticide resistance is associated with replacements of a single amino acid within the putative lining of a δ‐aminobutyric acid (GABA)‐gated chloride ion channel gene Resistance to dieldrin (Rdl). Only two resistance‐associated amino acid replacements have been identified; alanine to serine in Drosophila melanogaster, D. simulans, Aedes aegypti, and Tribolium castaneum and alanine to glycine as a second allele in D. simulans. Here we report that single stranded conformational polymorphism (SSCP) analysis of genomic DNA, amplified by the polymerase chain reaction (PCR) for exon 7 of the Rdl gene, can be used to genotype strains or individuals of all of these insects. This technique also appears simultaneously to distinguish between D. melanogaster and D. simulans, sibling species only reliably identifiable by examination of male genitalia. The relative advantages of this genotyping technique against other PCR‐mediated techniques in monitoring for insecticide resistance are discussed.
Steady‐state and transient analysis of integument penetration by insecticides
Authors: Salgado Vincent L. 
Published: November 2006

AbstractInsecticide penetration studies are usually done by applying a finite dose of material to a finite area of the integument in a solvent, such as acetone, that evaporates very quickly. The time‐course of penetration is then measured either as the buildup of material inside the insect or as the decline of material recoverable in a surface wash. Pharmacokinetic models are often used to describe such experiments, but identical models can be formulated from diffusion theory. Diffusion theory was applied to obtain equations that describe the steady‐state behavior of a single‐layer integument with partitioning between integument and solutions, and a double‐layer integument with partitioning between layers and between each layer and the adjacent solution. The steady‐state flux equations for both models were first‐order, and it was shown that this would be the case for steady‐state flux through any number of layers.The steady‐state analysis has two limitations. First, the assumption of a steady state implies that the concentration gradient across each layer of the integument is linear, and that this could not occur instantaneously. Second, the analysis assumes that material diffuses from a pool on the surface at some external concentration, whereas, ideally, it is applied as a plane source of infinite concentration. If the steady‐state assumption is rejected, the diffusion equation can be solved exactly, using Green's function, for diffusion of a topically applied dose across the integument modeled as a homogeneous plate, if the concentration at the internal face is assumed to remain zero. An analytical expression is obtained for concentration as a function of time and position in the integument, and from it are calculated flux into the insect and disappearance of material recoverable in a solvent wash, where material is assumed to be recoverable to an arbitrary depth. For small values of recovery depth, recovery falls precipitously following application, then progressively more slowly as the experiment proceeds. This phenomenon has been seen in much published data, and is explained adequately for the first time by the theory presented here. Predicted flux into the insect rises with a delay and then falls, but its fall is not exponential, as is often assumed. Peak flux is predicted to be directly related to the diffusion coeficient. The impact of these results on the design of penetration experiments is discussed.
Foliar absorption of some glyphosate formulations and their efficacy on plants
Authors: Lærke Poul E. , Streibig Jens C. 
Published: November 2006

AbstractUptake of various doses (0.27–4.06 g litre−1) of glyphosate acid formulated with various concentrations (0.27–5.42 g litre−1) of two polyethoxylated alcohol surfactants ‘Genapol’ T‐150, ‘Genapol’ T‐250) in wheat (Triticum aestivum L. cv. Ralle) 24 h after application was studied. Both surfactants greatly enhanced glyphosate uptake at concentrations up to 1.35 g litre−1. Uptake could be slightly further improved by ‘Genapol’ T‐150 up to 5.42 g litre−1 while ‘Genapol’ T‐250 at this high concentration antagonized uptake a little. Uptake of glyphosate‐monoammonium formulated with a quaternary ammonium surfactant (‘Trimao’ (8PO)) in wheat and white mustard (Sinapis alba L. cv. Alba) was also studied. Uptake of glyphosate‐monoammonium in wheat was enhanced at surfactant concentrations up to 1.35 g litre−1. Beyond this concentration uptake continued to increase slightly but not significantly. Generally, glyphosatemonoammonium formulated with ‘Trimao’ (8PO) was not taken up as extensively by mustard as by wheat, and the optimum surfactant concentration is probably higher on mustard. The optimal combinations of surfactant concentration and glyphosate dose based on uptake 24 h after application were used in a time‐course study.Results from uptake studies were compared with the efficacy of similar formulations on wheat. The surfactant concentration range which gave the most pronounced effect on glyphosate uptake was found to be similar (0–1 g litre−1) in both studies. However, the surfactant concentration providing maximum herbicide uptake was found to be higher in the uptake study compared to the surfactant concentration providing optimal efficacy in the dose‐response experiments. A dose rate of 0.5 g litre−1 of ‘Tween’ 20 (sorbitan monolaurate surfactant) improved efficacy of a formulation with an optimal mix of glyphosate‐monoammonium and ‘Trimao’ (8PO). Ammonium sulfate (5.0 g litre−1) did not improve this formulation further.
Investigation on the transformation of fluchloralin by soil fungi: Identification of some metabolites
Authors: Guha Prabir K. , Saha Jayanta , Chaudhuri Subhendu , Pal Srikumar , Bhattacharyya Anjan , Adityachaudhury Narayan 
Published: November 2006

AbstractFluchloralin [N‐(2‐chloroethyl)‐α,α,α,‐trifluoro‐2,6‐dinitro‐N‐propyl‐p‐toluidine] was transformed by two common soil fungi, Aspergillus flavus Link and Fusarium solani (Mart.) Sacc. in pure culture. The fungi were isolated from enrichment cultures of an analogous herbicidal compound, pendimethalin [N‐(1‐ethylpropyl)‐2,6‐dinitro‐3,4‐xylidine)]. Transformation of fluchloralin by these fungi resulted in the formation of several metabolites, 13 of which were identified. Besides the known mechanisms of microbial transformation of dinitroanilines, methylation of the anilino nitrogen and direct elimination of a nitro group at 2 position from the aromatic ring without any further substitution were also observed.
Nerve insensitivity resistance to cypermethrin in larvae of the tobacco budworm Heliothis virescens from USA cotton field populations
Authors: McCaffery Alan R. , Holloway Jonathan W. , Gladwell Richard T. 
Published: November 2006

AbstractSpontaneous neuronal activity was recorded from the peripheral nerves of third‐instar larvae of strains of Heliothis virescens (F.) obtained directly from cotton fields in the USA. Following a control period the preparations were exposed to increasing concentrations of cis‐cypermethrin in a cumulative dose‐response assay. A positive response was defined as an increase of at least five‐fold in the rate of neuronal activity over that seen during the control period. Up to 35 individuals of each strain were assayed and the responses used to construct a phenotypic profile categorising the individuals from nerve‐susceptible to highly nerve‐insensitive. An EC50 for the action of cis‐cypermethrin was also obtained. There was a positive, significant correlation between non‐synergisable resistance to cypermethrin and nerve insensitivity as defined in the neurophysiological assay. It was shown that nerve insensitivity to cypermethrin increased throughout the cotton‐growing season.
Evaluation of different formulations of deltamethrin in comparison with permethrin for impregnation of netting
Authors: Elissa Nohal , Curtis Christopher F. 
Published: November 2006

AbstractFive formulations of deltamethrin and one of permethrin were impregnated into cotton and nylon netting and tested for their efficacy and persistence in killing Anopheles gambiae Giles which were attempting to penetrate the netting in search of blood meals. Emulsifiable concentrates persisted better than wettable powders of deltamethrin, and all the deltamethrin formulations performed better than permethrin, even though the latter was applied at an eight times higher dose. The insecticidal effect of both compounds persisted better on nylon than on cotton; it was adversely affected by repeated washing.