摘要:

AbstractAmmonium thiocyanate (I) was shown to inhibit the oxidation of aminotriazole (3‐amino‐1,2,4‐triazole) in two free‐radical generating systems: (a) riboflavin photo‐sensitised oxidation; and (b) oxidation by hydroxyl radicals. Evidence from in‐vitro studies is presented to show thatIcould enhance aminotriazole performance by being preferentially oxidised within the leaf, thereby preventing aminotriazole free‐radical formation and subsequent conjugation with amino acids and other compounds. This opens up the possibility of a whole new range of additives which could enhance translocation by inhibiting free‐radical reactions. A comparison of possible inhibitors revealed that cyanides, iodides and perhaps bromides may be of use in this respect. In addition to inhibiting free‐radical reactions,Iand potassium iodide (II) were shown to have a considerable effect on the uptake of aminotriazole by bean leaves (Phaseolus vulgarisvar. Canadian Wonder). In the absence of additives, uptake of aminotriazole was negligible (1.8%); in the presence of a 1:1 molar ratio ofIorII, uptake of aminotriazole was increased to 36.6% and 54.2% respectively. At a 3:1 molar ratio of additive:aminotriazole, the respective figures were 63.5% and 81.0%.IIappeared to be the more efficient of the two additives at higher humidity. However, the results and observations indicated that the situation may be reversed under low‐

ISSN:0031-613X    

DOI:10.1002/ps.2780100402

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThirteen pyrethroid‐type esters of substituted 1(or 3)‐hydroxymethylimidazolidine‐2, 4‐dione were synthesised and their knockdown activities against houseflies, mosquitoes and cockroaches were examined. Knockdown activities of 2,4‐dioxo‐1‐prop‐2‐ynylimidazolidin‐3‐ylmethyl esters in oil solutions were higher than those of known knockdown pyrethroids; three of the compounds also possessed strong knockdown and flushing‐out activit

ISSN:0031-613X    

DOI:10.1002/ps.2780100403

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractPermethrin was metabolised by attack at the ester bond,in vivoby adult cockroaches,Periplaneta americanaandin vitroby esterase preparations. Metabolites retaining the ester linkage could not be detected. In all cases, the (1RS)‐trans‐isomer (transpermethrin) was more labile than the (1RS)‐cis‐isomer. Cypermethrin was metabolised at one‐fifth the rate for permethrin. In‐vitro and in‐vivo studies with synergists indicated that cleavage of the ester bond in permethrin can be both oxidative for the (1RS)‐cis‐isomer and hydrolytic for the (1RS)‐trans‐isomer. The penetration of permethrin through the cuticle of the cockroach was significantly greater than that of cypermethrin. The penetration and metabolism of permethrin and cypermethrin in sixth‐instar larvae of susceptible and resistant strains of the Egyptian cotton‐leafworm,Spodoptera littoralis, were studied as possible factors in resistance. No significant differences were found. It is suggested that the major resistance factor to permethrin inS. littoralis

ISSN:0031-613X    

DOI:10.1002/ps.2780100404

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractEllman's method of cholinesterase assay which is often used for residue analysis of organophosphorus insecticides has been modified by adding the protein denaturant, sodium dodecyl sulphate, to control the duration of the reaction. In doing so, the reaction time can be standardised to facilitate the measurement in a field laboratory of residues of water‐soluble organophosphates, particularly on plant surfaces that have been subjected to sprays. Thirty samples can be analysed in 1 h by timing each step of the procedure for a series of 30 reaction tubes at 1‐min intervals from the incubation of the enzyme with the insecticide to the final addition of the sodium dodecyl sulphate. Results from a series of aerial spray trials are presented and discussed briefly as an example of a field application of the met

ISSN:0031-613X    

DOI:10.1002/ps.2780100405

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractPhotolysis on soil surfaces of the organophosphorus insecticides diazinon, methidathion and profenofos was studied under artificial sunlight conditions. All three compounds were readily degraded under the conditions used. The rate of degradation decreased in the order diazinon, profenofos, methidathion and was always greater in moist than in dry soil. The same order of stability was also observed from photolysis studies in aqueous solution. The major photolysis products identified were 2‐isopropyl‐6‐methylpyrimidin‐4‐ol from diazinon, 5‐methoxy‐3H‐1,3,4‐thiadiazol‐2‐one from methidathion and 4‐bromo‐2‐chlorophenol and 4‐bromo‐2‐chlorophenyl ethyl hydrogen phosphate from profenofos. The same compounds were formed in hydrolysis studies and also upon photodecomposition in aqueous solutions of diazinon and methidathion. Profenofos, however, showed a different photolytic reaction in aqueous systems, formingO‐(2‐chlorophenyl)O‐ethylS‐propyl phosphorothioate. Soil photolysis studies together with hydrolysis experiments could be a useful quick method for obtaining early information on the chemical breakdown products which a

ISSN:0031-613X    

DOI:10.1002/ps.2780100406

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractTopical application of gamma‐HCH induced considerable ultrastructural changes and damage in the cellular components of the neurohaemal organs on the median nerves ofCarausius morosus. The cytoplasm and nucleoplasm of the glial cells became much more opaque to electrons and shrinkage occurred in the cellular wrappings surrounding the nerve axons. The cytoplasm of the tracheal wall cells and end cells also increased in electron density. Damage to the nervous elements was less evident than to the glial cells but some clumping and increase in electron opacity of the axoplasm took place. Neurosecretory granules could fragment and/or become less opaque to electrons. Some axons that lacked a glial‐cell sheath and contained neurosecretory granules appeared to be disrupted or degenerating. At very high doses there was an apparent reduction in the number of storage granules and an increase in exocytotic profiles in some neurosecretory axons. These results are discussed in relation to the possible modes of action of gamma‐HCH upon the nervous system of in

ISSN:0031-613X    

DOI:10.1002/ps.2780100407

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe main features of electron microscopy (EM) are outlined; transmission EM, high‐voltage transmission EM, scanning EM, scanning transmission EM and their uses in biological research are discussed. The use of these techniques with X‐ray analysis is mentioned and reference is made to the problems of specimen preparat

ISSN:0031-613X    

DOI:10.1002/ps.2780100408

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractAn introduction is provided to the basic ideas and theory of electron‐microprobe analysis as applied to biological tissue. The nature of characteristic and continuous X‐rays is outlined. X‐ray detectors, specimen preparation and the relative advantages and disadvantages of thick and thin section techniques are disc

ISSN:0031-613X    

DOI:10.1002/ps.2780100409

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe efficacy of a pesticidal formulation is in part affected by the surface to which it is applied. During the drying process, spray drops can interact with the complex microenvironment of trichomes, secretory glands, stomata, epicuticular wax and cuticle of the leaf epidermis. The subsequent uptake and persistence of the deposit can be further influenced by the action of the microclimate, including humidity, temperature, rain and dew. The scanning electron microscope (SEM), which is an instrument ideally suited for the study of the surface of bulk specimens, has been used to show the spreading and distribution of pesticides applied as sprays and individual drops to leaf surfaces. Particle size, crystal growth and co‐precipitation of the active ingredient with surfactants and other adjuvants have also been investigated. The SEM can also show how some pesticides and their adjuvants continue to be taken up by the leaf long after the drops have visibly dried. Phytotoxicity, sometimes associated with the penetration of active ingredient or formulation adjuvant, can also be demonstrated using the microscope, especially if either specifically emits cathodoluminescence. These images can also supply complementary information concerning the persistence of deposits, provided that interpretation of the results is carried out with care and, if possible, in conjunction with residue and biological assay

ISSN:0031-613X    

DOI:10.1002/ps.2780100410

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY

摘要:

AbstractThe sources and magnitudes of typical molecular, macromolecular and cytoplasmic motions in cells are reviewed and compared with the ability of the conventional light microscope to detect and quantify them. The principles of laser Doppler spectroscopy are introduced; the type and range of motions detectable are reviewed and found to be superior to conventional light microscopy in certain respects. A laser Doppler microscope system has been developed that allows accurate placement of the beam within the cell and combines visual monitoring of the cellular behaviour with the superior resolution of motions from spectroscopy. The system operates with a non‐destructive, low intensity, laser beam that permits continuous monitoring of diffusive and translational motions in living cell

ISSN:0031-613X    

DOI:10.1002/ps.2780100411

出版商:John Wiley&Sons, Ltd    

年代:1979

数据来源: WILEY