bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of herbicides on photosynthetic activity and transpiration rate of intact plants
Authors: van Oorschot J. L. P. 
Published: November 2006

AbstractThe effect of various herbicides on photosynthesis, respiration and transpiration of intact plants has been studied in a routine assembly. Simultaneous measurements were made under different experimental conditions in four small plant chambers, in which the shoots of various plant species can be accommodated.The herbicide is applied during measurement, so that the effect can be related to the photosynthetic activity of the same plants before treatment.The selectivity of various herbicides was studied by determining the capacity of a plant species to inactivate a herbicide absorbed by the roots. These and other differential effects of various herbicides on photosynthetic activity of different plant species coincide with the selective properties in the field. Such differences are also observed after leaf sprayings. The duration of the experiments is kept short.Bean plants were studied under various experimental conditions of air humidity, light intensity and temperature resulting in different transpiration rates. The decrease in photosynthetic activity owing to the presence of a herbicide in the nutrient solution at a standard concentration was more rapid at the higher transpiration rates. The total transpiration during treatment up to 50% inhibition of photosynthesis was constant under the various experimental conditions.Specific inhibitors of the photosynthetic process had a more pronounced effect on the photosynthetic activity than on transpiration rate. Some other herbicides affect transpiration as well as photosynthesis.
Chemical structure and physical properties of candidate insecticides in relation to residual toxicity to adult mosquitos
Authors: Barlow F. , Hadaway A. B. 
Published: November 2006

AbstractData are presented on changes in physical properties and insecticidal activity resulting from modifications in chemical structure in two groups of compounds. The first group consists of propoxur and three closely related N‐methylcarbamates and the corresponding N‐acetyl compounds The parent compounds are all highly toxic to adult mosquitos by topical application in solution and deposits from water‐dispersible powder formulations on plywood and plaster of Paris panels have long residual activity. N‐acetylation is not accompanied by excessive loss of toxicity to mosquitos, but increases volatility to the extent that none of the four N‐acetyl derivatives can be considered as potential residual insecticides. The second group consists of tetrachlorvinphos and related vinyl phosphates and vinyl phosphorothionates which show a wide range of toxicity both to adult mosquitos and to mammals.
Mechanisms of action and structure activity relations of herbicides that inhibit photosynthesis
Authors: Büchel K. H. 
Published: November 2006

AbstractA survey and chemical classification are given for the most important herbicidal inhibitors of photosynthesis. The photochemical reactions involved in photosynthesis are reviewed. The herbicides discussed here all interfere with photosynthetic electron transport in the light reactions. Comments are made on the redox catalysts and the electron transport chain. The mode of action of the herbicides due to inhibition of the light reactions I and II or of photophosphorylation are described. Structure activity correlations according to the regression analysis (Hansch‐approach) are discussed with examples in the classes of acetanilides, benzimidazoles and triazinones. The correlation studies in the series of the Hill‐reaction inhibitors have led to a model for the essential structural elements. Some work on the problem of selectivity and its importance is reviewed.
Inhibitors of shikimate dehydrogenase as potential herbicides
Authors: Baillie A. C. , Corbett J. R. , Dowsett J. R. , McCloskey P. 
Published: November 2006

AbstractShikimate dehydrogenase (E.C. 1.1.1.25) is found in plants but not in animals and is therefore an attractive target for a new herbicide. A series of 1,6‐dihydroxy‐2‐oxoisonicotinic acid derivatives was prepared and shown to inhibit the enzyme reversibly. Weak active‐site directed irreversible inhibitors based on these compounds were also synthesised but none was herbicidal.
The effects of small applications of an organophosphorus poison, fenthion on the weaver‐bird Quelea quelea
Authors: Pope G. G. , Ward P. 
Published: November 2006

AbstractExperiments were carried out in East Africa to determine the effects of single‐drop applications of the avicide Queletox (active ingredient fenthion) on the Red‐billed Quelea Q. quelea, an important agricultural pest.Birds treated with relatively large amounts of Queletox died within a few hours, as expected. Most of those receiving the smallest lethal doses died 12 to 48 h after treatment. From their terminal fat and muscle condition it was concluded that they died of starvation, despite their apparently healthy appearance following treatment and the easy availability of suitable food.LD50's of 80 and 220 mg/kg were obtained for Queletox applied to the feathers of the back in drops of varying sizes or concentrations, the amount of solvent having an important effect on the toxicity.The possibility is raised of reducing the amounts of Queletox used in control operations against the birds, making them safer and cheaper.
The application of granular pesticides
Authors: Nation H. J. 
Published: November 2006

AbstractThree basic processes are involved in the application of granular pesticides—metering, transporting and distributing. Metering may be simply dependent upon flow through an orifice under gravity but preferably force‐feed mechanisms, usually driven in relation to forward speed are used. Transport may be effected merely under gravity, but pneumatics is also an accepted method particularly for large swath widths. Kinetic energy is also an agency in transporting granules as in “throwing” type distributors and this also achieves the distribution element. With gravity and pneumatic transport the final distribution is usually by spreaders or by nozzles at each outlet.Assessment of performance is rendered difficult by the very small size of the particles to be detected and the very low rates of application usually employed. Data are required on the appropriate sampling areas which should be used in assessing uniformity of distribution and the significance of the variations measured.Cooperation between all the disciplines of workers in the field is necessary for further development of the technique and in particular in the field of formulation a valuable contribution would be in the reduction in the diversity of physical properties of all the granular materials in use or projected.
Spectroscopic studies on the mechanisms of adsorption of paraquat by humic acid and model compounds
Authors: Burns Ian G. , Hayes Michael H. B. , Stacey Maurice 
Published: November 2006

AbstractChanges in the relative sizes of the carboxylic absorption bands in the infrared spectra (near 1730 and 1610 cm−1) of adsorbents before and after treatment with paraquat (1,1′‐dimethyl‐4,4′‐bipyridylium dichloride) showed that ion exchange is the predominant mechanism for adsorption of the bipyridyl by H+‐ ion saturated preparations of a humic acid from an organic soil, by two hydroquinone polymers and by two carboxylic ion‐exchange resins. Attempts to relate the extents of saturation (with adsorbate) of the exchange sites with the optical densities of the infrared bands were unsuccessful because of deviations from Beer's Law. Ultraviolet spectroscopy failed to provide evidence for charge transfer mechanisms in paraquat‐humic acid complexes in aqueous systems.
Studies on the persistence of the organotin fungicide fentin acetate (triphenyltin acetate) in the soil and on surfaces exposed to light
Authors: Barnes Roger D. , Bull Alan T. , Poller Robert C. 
Published: November 2006

AbstractThe results of a study into the persistence of triphenyltin (=fentin) acetate in soil are presented. The fungicide is degraded biologically 50% being decomposed in 140 days. The photochemical degradation of fentin acetate into inorganic tin via diphenyltin and monophenyltin compounds also is demonstrated. The leaching of fentin acetate in soil and its effect on soil nitrification is discussed.
Charges on fungal spores
Authors: Fisher D. J. 
Published: November 2006

AbstractA survey is made of the use of microelectrophoresis to study surface charges on fungal spores in aqueous suspension. The method involves observation of individual spores under the microscope and measurement of rates of migration in a known potential gradient. Charge characteristics can be modified by specific chemical and enzymic treatments and provide a means of identifying surface ionogenic groups. The technique has also been used to demonstrate the presence of surface lipid. The surface components of a wide range of fungal spores are discussed. Studies of reactions of cationic fungicides at the surface of spores and stabilised protoplasts are also reviewed.
The degradation of quintozene, pentachlorobenzene, hexachlorobenzene and pentachloroaniline in soil
Authors: Beck JØrgen , Hansen Knud E. 
Published: November 2006

AbstractThe disappearance of quintozene (I) and its technical impurities and metabolites pentachlorobenzene (III), hexachlorobenzene (IV) and pentachloroaniline (V) from soil, was studied in laboratory experiments under controlled conditions during a period of about 600 days. The very high persistence found, was confirmed by the analysis of 22 samples collected from fields used for potato growing and treated regularly during the foregoing 11 years with commercial formulations of quintozene. In the laboratory experiments, III, V and methylthiopentachlorobenzene (VI) were found to be degradation products from the quintozene.
A note on the mode of action of the systemic fungicide tridemorph
Authors: Fisher David J. 
Published: November 2006

AbstractThe effects of the systemic fungicide tridemorph on fungal and plant protoplasts have been investigated. No evidence of reaction at the plasma‐membrane was revealed by microelectrophoresis. The fungicide did not affect oxygen uptake by fungal protoplasts but incorporation of labelled histidine was reduced. Fungi‐toxicity tests showed that tridemorph had little effect on spore germination but inhibited mycelial growth. It is suggested that the fungicide may act by interfering with the synthesis of proteins essential for hyphal extension.
The use of computers with chemical structural information: ICI CROSSBOW system
Authors: Eakin Diane R. , Hyde Ernest , Palmer Graham 
Published: November 2006

AbstractScientists ask several different types of question involving chemical structures with other property data. ICI has considered these question types in developing the CROSSBOW system for chemical structure recording and search. The system relies on the use of the Wiswesser Line‐Formula Notation to represent structures as compact, logical, unique and unambiguous codes suitable for computer processing.The notations can be converted into detailed explicit descriptions of molecular structure known as connection tables. These allow the most exact atom‐by‐atom search technique for a specified atomic network anywhere in the molecule. To facilitate more general searches, and to provide a screen to reduce input to the exhaustive atom‐by‐atom procedure, two other chemical search techniques are implemented. The first is a fast search for the occurrence of certain chemical fragments, using a fragment set generated from the notations: the second is a search of the notations themselves for symbol strings relating to the required substructure.Output from the search is in the form of structural diagrams generated from the connection tables. Data from associated property files can be displayed along with the structures, or searched as an additional parameter. The CROSSBOW system operates not only on ICI internal files, but also on commercially‐available data bases. These include the Aldrich chemical catalogue, the Index Chemicus Registry System current awareness tapes, and Hansch structure/activity files.
Determination of impurities in technical fenitrothion by liquid chromatography
Authors: Marshall W. D. , Greenhalgh R. , Bátora V. 
Published: November 2006

AbstractGas and liquid chromatographic methods were evaluated for determining the impurities in technical grade fenitrothion (≥95%). These impurities were S‐methyl fenitrothion. fenitrooxon, bis‐fenitrothion, S‐methyl‐bis‐fenitrothion and 3‐methyl‐4‐nitrophenol. The GC proved to be insensitive to the two bis compounds whereas these compounds could be analysed by liquid chromatography on a Corasil 11 column or on an OPN column.Nine technical samples were analysed and S‐methyl fenitrothion, a potent anticholinesterase agent, was by far the most common impurity.
Analysis of foods for methomyl using thin‐layer chromatography after low temperature clean‐up
Authors: McLeod Harry A. , Mendoza Celso E. , McCully Keith A. 
Published: November 2006

AbstractThe recovery of methomyl from fortified food samples was determined semi‐quantitatively by a multi‐pesticide residue screening procedure with thin‐layer chromatography enzyme inhibition as the detection system. The estimated recoveries from milk, eggs, beef, honey, butter, pork, peas and cabbage were variable: 70–90% for samples fortified at 0.5 mg/kg and 40–90% for 0.05 mg/kg. Emulsion formation during liquid‐liquid partition was not encountered.
Coating and impregnating with endrin protects field‐sown douglas fir seed
Authors: Crouch Glenn L. , Radwan Mohamed A. 
Published: November 2006

AbstractChemically treated and untreated Douglas fir seed was evaluated in the laboratory and at four locations on National Forests in Oregon and Washington. Seed was treated by coating with endrin or endrin‐thiram and by impregnation with endrin. In the laboratory, germination was adversely affected by impregnation and by field exposure. Also, bioassays of treated seed showed no differences in consumption by deer mice among endrin treatments, but more seed was eaten after exposure in the field than before. Deer mice were the most common seed eaters found on all field study areas, and their numbers exceeded the level prescribed as a minimum requiring protection prior to seeding. Observations during and at the end of two growing seasons indicated that seedling production and stocking were much greater from endrin‐treated than untreated seed, but there were no significant differences among the three endrin treatments. In addition, performance of treated and untreated seed differed by area, with best results at the two locations known for favourable climatic conditions.
Metabolic aspects of the toxicology of diazinon. I. Hepatic metabolism in the sheep, cow, pig, guinea‐pig, rat, turkey, chicken and duck
Authors: Machin Antony F. , Rogers Heather , Cross Alan J. , Quick Michael P. , Howell Laurence C. , Janes Norman F. 
Published: November 2006

AbstractThe phosphorothionate insecticide diazinon was incubated with liver microsomes from the sheep, cow, pig, guinea‐pig, rat, turkey, chicken and duck. Metabolism by liver slices of most of these species was also examined. Hydroxydiazinon, isohydroxydiazinon, dehydrodiazinon, their oxons and diazoxon were identified and determined quantitatively or semi‐quantitatively. An eighth metabolite was tentatively identified as the 6‐aldehyde analogue of diazinon. Yields and rates of production of these metabolites varied greatly between species. Production of oxons was not generally correlated with susceptibility to diazinon poisoning, although it was lowest in the least susceptible animal, the sheep. The degradation of oxons by liver slices was too slow to explain the low toxicity of diazinon to the mammals. The relative importance of hepatic and extrahepatic metabolism in determining toxicity to vertebrates is discussed.
Some laboratory investigations relevant to the possible use of new pyrethroids in control of mosquitoes and tsetse flies
Authors: Barlow Fred , Hadaway Alan B. , Flower Leonard S. , Grose James E. H. , Turner Christopher R. 
Published: November 2006

AbstractCypermethrin, fenvalerate, permethrin, (S)‐α‐cyano‐3‐phenoxybenzyl (1R,cis)‐3‐(2, 2‐dibromovinyl)‐2, 2‐dimethylcyclopropanecarboxylate (NRDC 161) and (R,S)‐α‐cyano‐3‐phenoxybenzyl 2, 2,3, 3‐tetramethylcyclopropanecarboxylate (S‐3206; WL 41706) have been tested against adult mosquitoes (Anopheles stephensi) and tsetse flies (Glossina austeni). They possess many of the necessary characteristics such as high intrinsic toxicity, low volatility, and high stability but vary considerably in the contact action of their spray residues.
A simple method of determining the aqueous solubility of organic substances
Authors: Fürer Richard , Geiger Max 
Published: November 2006

AbstractA new method is described in which a very fine suspension of the substance in water is diluted in a stepwise fashion; there is a sudden disappearance of the turbidity as soon as the aqueous solubility concentration range is reached. An instrument for micronising crystalline substances prior to the solubility determination has been designed. The method is simple and rapid and requires neither complicated apparatus nor analytical procedures. It is suitable for determining aqueous solubilities in the range from more than 1000 to less than 1 mg/litre. As a visual method, it would seem a priori to be less accurate than the “analytical” procedures recently described in the literature. When the solubility values given by different workers for the same substance are compared, however, discrepancies of a factor up to 10 are occasionally found. The accuracy obtainable with this new method readily suffices for the objective in view, namely to investigate to what extent the aqueous solubility of pesticide chemicals affects their behaviour during and after application. The aqueous solubilities of 34 commercial pesticide chemicals are tabulated; only in a few cases do the values obtained by the dilution method differ widely from those given in the 4th edition of the Pesticide Manual.
The effect of drop size and velocity on the performance of agricultural sprays
Authors: Lake John R. 
Published: November 2006

AbstractThe sizes and velocities of drops in sprays from farm sprayers are considered in relation to their impaction on plant surfaces. Examples from a study being carried out at the National Institute of Agricultural Engineering (NIAE) are given. The results showed that young leaves of barley (cv Mazurka) and wild oats (Avena fatua L.) were difficult to wet, only the smallest drops applied (about 100 um diameter) being readily retained. In the context of weed control in cereals the importance of detrmining the effect of the form of plant deposits on herbicidal activity is discussed, and examples of results of a joint study between the NIAE and the Agricultural Research Council Weed Research Organization are given.
Fenbendazole. I. Structure‐activity relationships
Authors: Loewe Heinz , Urbanietz Josef 
Published: November 2006

AbstractSubstitution of alkyl benzimidazol‐2‐ylcarbamates by phenoxy‐ or phenylthio‐groups in the 5‐position results in an increase in anthelmintic activity. The biological spectrum is altered by substitution of the phenyl ring. A sulphonic ester substituent in the 5‐position of the benzimidazole nucleus also increases anthelmintic activity.
The metabolism of the pyrethroid insecticide (±)‐α‐cyano‐3‐phenoxybenzyl 2,2,3,3‐tetramethyl‐cyclopropanecarboxylate, WL 41706, in the rat
Authors: Crawford Maureen J. , Hutson David H. 
Published: November 2006

AbstractThe metabolism of the pyrethroid insecticide α‐cyano‐3‐phenoxybenzyl 2,2,3,3‐tetramethylcyclopropanecarboxylate (WL 41706) has been studied in rats using two forms of 14C‐labelling (benzyl‐ and cyclopropyl‐). Excretion of benzyl−14C was rapid, 57% of the administered dose being eliminated in the urine 48 h after treatment and 40% in the faeces. No significant sex difference was observed. The amount of radioactivity excreted via expired gases was 0.005% of the administered dose and less than 1.5% of the dose remained in the animals 8 days after treatment. The mean percentage recovery of administered dose was 104% for male rats and 97% for female rats. Urinary and faecal metabolites from these rats, and from rats dosed similarly with [cyclopropyl−14C]‐WL 41706 were studied. The rapid metabolism of WL 41706 is due to efficient cleavage of the ester bond by rats in vivo to afford 2,2,3,3‐tetramethylcyclopropanecarboxylic acid (partly as glucuronide) and the 3‐phenoxybenzyl moiety. Before this cleavage occurs, however, about half of the intake suffers aryl hydroxylation giving the α‐cyano‐3‐(4‐hydroxyphenoxy)benzyl ester, part of which is excreted in the bile as a conjugate(s) and part of which is cleaved and eliminated as the O‐sulphate of 3‐(4‐hydroxyphenoxy)benzoic acid and the glucuronide of 2,2,3,3‐tetramethylcyclopropanecarboxylic acid. A minor amount of hydroxylation occurs at a trans‐methyl group on the cyclopropane acid moiety. The metabolism of WL 41706 by rat liver occurs mainly in the microsomes and mainly via oxidative processes.
Metamitron activity in tolerant and susceptible plants
Authors: Schmidt Robert R. , Fedtke Carl 
Published: November 2006

AbstractThe herbicidal activity of metamitron, its inhibition of photosynthesis and its metabolism were studied in a number of plant species. An enzymic, light‐independent deamination produces an inactive metabolite. Metabolism is rapid in plants tolerant to metamitron, e.g. Mercurialis annua and particularly sugar beet (Beta vulgaris L.), but slower in susceptible plants, e.g. Amaranthus retroflexus.
Kinetics of hydrolysis of atrazine in aqueous fulvic acid solution
Authors: Khan Shahamat U. 
Published: November 2006

AbstractThe hydrolysis of atrazine in aqueous fulvic acid solution followed first‐order kinetics with respect to the herbicide concentration. The half‐life of atrazine, calculated from first‐order plots, was lowest at low pH and increased as the pH of the reaction mixture increased. Increase in fulvic acid concentration resulted in a higher hydrolysis rate constant and a shortened half‐life but had no effect on the activation energy. However, the latter increased with increase in pH of the reaction mixture. The only product identified after hydrolysis in fulvic acid solution was 2‐ethylamino‐4‐hydroxy‐6‐isopropylamino‐1,3,5‐triazine.
Degradation of the herbicide [14C]‐diclofop‐methyl in soil under different conditions
Authors: Martens Rainer 
Published: November 2006

AbstractThe degradation of the herbicide diclofop‐methyl, ( ± )‐methyl 2‐[4‐(2,4‐dichloro‐phenoxy)phenoxy]propionate, was investigated in two agricultural soils under aerobic and anaerobic conditions. Using two differently labelled forms of [14C]‐diclofop‐methyl the qualitative as well as the quantitative formation of extractable metabolites was followed for 64 days. The mineralisation of the uniformly labelled aromatic rings was pursued by monitoring the 14CO2 generated for 25 weeks. As a first step of the degradation a very rapid hydrolysis of the ester bond was detected under all conditions. Diclofop, the corresponding substituted propionic acid formed, was extensively degraded under aerobic conditions, the final product being 14CO2. As an intermediate, a compound later identified by GLC/MS to be 4‐(2,4‐dichlorophenoxy)phenol, was found in the extracts. Furthermore, traces of six other unknown metabolites were detected. Under anaerobic conditions the degradation proceeded to a small extent. At most 3% of the applied radioactivity was accounted for by the degradation product 4‐(2,4‐dichlorophenoxy)phenol. No other metabolite, including 14CO2, was observed, implying lack of any further degradation.