Pub Date : 1998-07-01DOI: 10.1002/(SICI)1096-9063(199807)53:3<201::AID-PS760>3.0.CO;2-#
D. Hedley, B. Khambay, A. Hooper, R. Thomas, A. Devonshire
A range of potential proinsecticides was synthesised and tested against insecticide-susceptible and -resistant clones of Myzus persicae (Sulzer). They were all esters of compounds known to be toxic or pharmacologically active, and were designed to have increased lipophilicity and to be subject to more rapid activation by hydrolysis in resistant than in susceptible aphids due to the increased amount of esterase present in the resistant clones. The most potent toxins were esters of monofluoroacetic acid. When applied topically, the toxicity of these esters to M. persicae was directly proportional to the esterase content of the aphids. Such compounds would not be suitable as commercial insecticides, but the results serve to illustrate the potential benefits of exploiting a resistance mechanism against one class of compounds to render another class more toxic, i.e. to design compounds that show negative cross-resistance. (C) 1998 SCI.
{"title":"Proinsecticides effective against insecticide-resistant peach-potato aphid (Myzus persicae (Sulzer))","authors":"D. Hedley, B. Khambay, A. Hooper, R. Thomas, A. Devonshire","doi":"10.1002/(SICI)1096-9063(199807)53:3<201::AID-PS760>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199807)53:3<201::AID-PS760>3.0.CO;2-#","url":null,"abstract":"A range of potential proinsecticides was synthesised and tested against insecticide-susceptible and -resistant clones of Myzus persicae (Sulzer). They were all esters of compounds known to be toxic or pharmacologically active, and were designed to have increased lipophilicity and to be subject to more rapid activation by hydrolysis in resistant than in susceptible aphids due to the increased amount of esterase present in the resistant clones. The most potent toxins were esters of monofluoroacetic acid. When applied topically, the toxicity of these esters to M. persicae was directly proportional to the esterase content of the aphids. Such compounds would not be suitable as commercial insecticides, but the results serve to illustrate the potential benefits of exploiting a resistance mechanism against one class of compounds to render another class more toxic, i.e. to design compounds that show negative cross-resistance. (C) 1998 SCI.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"37 1","pages":"201-208"},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91320045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.1002/(SICI)1096-9063(199802)52:2<97::AID-PS687>3.0.CO;2-#
F. Westwood, K. Bean, A. Dewar, R. Bromilow, K. Chamberlain
[ 14 C]Imidacloprid was applied to pelleted seeds of sugar beet which were then grown in pots of field soil. Leaves, roots and soil were analysed at intervals up to 97 days after planting and the distributions of parent compound and of several metabolites were quantified. At the first sampling, 21 days after application, parent imidacloprid was the main compound found in the leaves and its concentration averaged 15.2 μg g -1 fresh weight. By the 25-leaf stage, 97 days after sowing, the concentration of parent compound in the leaves had fallen to an average of 0.5 μg g -1 ; the metabolites and parent compound in the leaves then represented respectively 44.5% and 4.5% of the total applied radioactivity. In the root at 97 days, parent imidacloprid and its metabolites together accounted for only 0.1% of the applied activity, whilst in the soil there was 23% of parent compound and 4% as metabolites. The persistence of both parent imidacloprid and the olefinic metabolite, which has recently been shown to have higher aphicidal activity than the parent imidacloprid, explains the prolonged control of aphids observed with imidacloprid in both glasshouse and field trials.
{"title":"Movement and persistence of [14C]imidacloprid in sugar-beet plants following application to pelleted sugar-beet seed","authors":"F. Westwood, K. Bean, A. Dewar, R. Bromilow, K. Chamberlain","doi":"10.1002/(SICI)1096-9063(199802)52:2<97::AID-PS687>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199802)52:2<97::AID-PS687>3.0.CO;2-#","url":null,"abstract":"[ 14 C]Imidacloprid was applied to pelleted seeds of sugar beet which were then grown in pots of field soil. Leaves, roots and soil were analysed at intervals up to 97 days after planting and the distributions of parent compound and of several metabolites were quantified. At the first sampling, 21 days after application, parent imidacloprid was the main compound found in the leaves and its concentration averaged 15.2 μg g -1 fresh weight. By the 25-leaf stage, 97 days after sowing, the concentration of parent compound in the leaves had fallen to an average of 0.5 μg g -1 ; the metabolites and parent compound in the leaves then represented respectively 44.5% and 4.5% of the total applied radioactivity. In the root at 97 days, parent imidacloprid and its metabolites together accounted for only 0.1% of the applied activity, whilst in the soil there was 23% of parent compound and 4% as metabolites. The persistence of both parent imidacloprid and the olefinic metabolite, which has recently been shown to have higher aphicidal activity than the parent imidacloprid, explains the prolonged control of aphids observed with imidacloprid in both glasshouse and field trials.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"8 1","pages":"97-103"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85261698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-02-01DOI: 10.1002/(SICI)1096-9063(199802)52:2<111::AID-PS695>3.0.CO;2-#
K. Grossmann, Florene Scheltrup
Investigations were conducted to elucidate the mechanism of selectivity of the auxin herbicide, quinmerac, in cleavers (Galium aparine) and the tolerant crops sugarbeet (Beta vulgaris), oilseed rape (Brassica napus) and wheat (Triticum aestivum). After root treatment with the herbicide, the selectivity has been quantified as approximately 400-fold between oilseed rape and Galium and 1000-fold between sugarbeet or wheat and the weed species. When 1 and 10 μM [ 14 C]quinmerac were applied for 4 h, no significant differences between root absorption and translocation of 14 C by Galium and the crop species were found. After 16 h, metabolism of [ 14 C]quinmerac to the biologically inactive hydroxymethyl and dicarboxylic acid derivatives was more rapid in wheat and sugarbeet than in Galium. In oilseed rape, a lower rate of herbicide metabolism was observed. In Galium, accumulations of abscisic acid (ABA), triggered by quinmerac-stimulated ethylene biosynthesis, were found to cause the herbicidal growth inhibition which develops during 24 h of application. Within 1 h of treatment, quinmerac stimulated 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity and ACC concentration specifically in Galium shoot tissue. During the next 4 h, ACC synthase activity was increased up to 50-fold, relative to the control. Within 3 h of exposure to quinmerac, increased ethylene formation followed by higher ABA levels was detected. In sugarbeet, oilseed rape and wheat, quinmerac did not stimulate ACC synthase activity and ACC and ABA levels. It is suggested that (i) the selectivity of quinmerac is primarily based upon the lower sensitivity to the herbicide of the tissue/target in the crop species, (ii) the induction process of the ACC synthase activity in the shoot tissue is the primary target of herbicidal interference. In wheat and sugarbeet, tolerance to quinmerac is additionally increased by a more rapid metabolism.
{"title":"Studies on the mechanism of selectivity of the auxin herbicide quinmerac","authors":"K. Grossmann, Florene Scheltrup","doi":"10.1002/(SICI)1096-9063(199802)52:2<111::AID-PS695>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199802)52:2<111::AID-PS695>3.0.CO;2-#","url":null,"abstract":"Investigations were conducted to elucidate the mechanism of selectivity of the auxin herbicide, quinmerac, in cleavers (Galium aparine) and the tolerant crops sugarbeet (Beta vulgaris), oilseed rape (Brassica napus) and wheat (Triticum aestivum). After root treatment with the herbicide, the selectivity has been quantified as approximately 400-fold between oilseed rape and Galium and 1000-fold between sugarbeet or wheat and the weed species. When 1 and 10 μM [ 14 C]quinmerac were applied for 4 h, no significant differences between root absorption and translocation of 14 C by Galium and the crop species were found. After 16 h, metabolism of [ 14 C]quinmerac to the biologically inactive hydroxymethyl and dicarboxylic acid derivatives was more rapid in wheat and sugarbeet than in Galium. In oilseed rape, a lower rate of herbicide metabolism was observed. In Galium, accumulations of abscisic acid (ABA), triggered by quinmerac-stimulated ethylene biosynthesis, were found to cause the herbicidal growth inhibition which develops during 24 h of application. Within 1 h of treatment, quinmerac stimulated 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity and ACC concentration specifically in Galium shoot tissue. During the next 4 h, ACC synthase activity was increased up to 50-fold, relative to the control. Within 3 h of exposure to quinmerac, increased ethylene formation followed by higher ABA levels was detected. In sugarbeet, oilseed rape and wheat, quinmerac did not stimulate ACC synthase activity and ACC and ABA levels. It is suggested that (i) the selectivity of quinmerac is primarily based upon the lower sensitivity to the herbicide of the tissue/target in the crop species, (ii) the induction process of the ACC synthase activity in the shoot tissue is the primary target of herbicidal interference. In wheat and sugarbeet, tolerance to quinmerac is additionally increased by a more rapid metabolism.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"36 1","pages":"111-118"},"PeriodicalIF":0.0,"publicationDate":"1998-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78943441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-01DOI: 10.1002/(SICI)1096-9063(199711)51:3<315::AID-PS627>3.0.CO;2-#
A. McCaffery, D. Head, T. Jianguo, A. Dubbeldam, V. R. Subramaniam, A. Callaghan
A neurophysiological assay developed previously was used to assess the incidence of nerve insensitivity resistance to synthetic pyrethroids in field strains of Helicoverpa armigera. Almost 70% of individuals from a sample of a highly pyrethroid-resistant population from Jiangsu Province, China were nerve-insensitive. Subsequent selection resulted in a strain homogeneous for expression of this mechanism. Likewise, over 95% of a sample from a strain of the insects from Andhra Pradesh, India were nerve-insensitive and a homogeneous strain was developed. Development of a nerve-insensitive laboratory strain of Heliothis virescens was undertaken but homozygosity could not be obtained. It is suggested that high fitness costs may be associated with this mechanism. The incidence of nerve insensitivity in Heliothine pests is reviewed and the role of phenotypic expression assays in molecular studies highlighted.
{"title":"Nerve insensitivity resistance to pyrethroids in heliothine Lepidoptera","authors":"A. McCaffery, D. Head, T. Jianguo, A. Dubbeldam, V. R. Subramaniam, A. Callaghan","doi":"10.1002/(SICI)1096-9063(199711)51:3<315::AID-PS627>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199711)51:3<315::AID-PS627>3.0.CO;2-#","url":null,"abstract":"A neurophysiological assay developed previously was used to assess the incidence of nerve insensitivity resistance to synthetic pyrethroids in field strains of Helicoverpa armigera. Almost 70% of individuals from a sample of a highly pyrethroid-resistant population from Jiangsu Province, China were nerve-insensitive. Subsequent selection resulted in a strain homogeneous for expression of this mechanism. Likewise, over 95% of a sample from a strain of the insects from Andhra Pradesh, India were nerve-insensitive and a homogeneous strain was developed. Development of a nerve-insensitive laboratory strain of Heliothis virescens was undertaken but homozygosity could not be obtained. It is suggested that high fitness costs may be associated with this mechanism. The incidence of nerve insensitivity in Heliothine pests is reviewed and the role of phenotypic expression assays in molecular studies highlighted.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"191 1","pages":"315-320"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77478819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-11-01DOI: 10.1002/(SICI)1096-9063(199711)51:3<271::AID-PS642>3.0.CO;2-#
M. D. Waard
ATP-binding cassette (ABC) transporters are members of a protein superfamily which can be responsible for efflux of drugs from cells of target organisms. In this way, the transporters may provide a mechanism of protection against cytotoxic drugs. In laboratory-generated mutants of fungi, overproduction of ABC transporters can cause multi-drug resistance to azoles and other non-related toxicants. The impact of this mechanism of resistance in field populations with decreased sensitivity to azoles remains to be established. Inhibitors of ABC transporter activity may synergize activity of azoles to populations of both sensitive and azole-resistant pathogens. The natural function of ABC transporters in plant pathogenic fungi may relate to transport of plant-defence compounds or fungal pathogenicity factors. Therefore, inhibitors of ABC transporter activity may act as disease control agents with an indirect mode of action.
{"title":"Significance of ABC transporters in fungicide sensitivity and resistance.","authors":"M. D. Waard","doi":"10.1002/(SICI)1096-9063(199711)51:3<271::AID-PS642>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199711)51:3<271::AID-PS642>3.0.CO;2-#","url":null,"abstract":"ATP-binding cassette (ABC) transporters are members of a protein superfamily which can be responsible for efflux of drugs from cells of target organisms. In this way, the transporters may provide a mechanism of protection against cytotoxic drugs. In laboratory-generated mutants of fungi, overproduction of ABC transporters can cause multi-drug resistance to azoles and other non-related toxicants. The impact of this mechanism of resistance in field populations with decreased sensitivity to azoles remains to be established. Inhibitors of ABC transporter activity may synergize activity of azoles to populations of both sensitive and azole-resistant pathogens. The natural function of ABC transporters in plant pathogenic fungi may relate to transport of plant-defence compounds or fungal pathogenicity factors. Therefore, inhibitors of ABC transporter activity may act as disease control agents with an indirect mode of action.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"138 1","pages":"271-275"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77481828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1997-05-01DOI: 10.1002/(SICI)1096-9063(199705)50:1<67::AID-PS552>3.0.CO;2-#
D. Herbert, K. A. Walker, L. Price, D. Cole, K. Pallett, S. M. Ridley, J. Harwood
Acetyl-CoA carboxylase catalyses the first committed step in fatty acid (and acyl lipid) formation. The enzyme has been shown to exert a high degree of flux control for lipid biosynthesis in leaves and, therefore, it is not surprising that chemicals which can inhibit it effectively are successful herbicides. These chemicals belong mainly to the cyclohexanedione and aryloxyphenoxypropionate classes and are graminicides. The reason for the selectivity of these herbicides towards grasses lies in the nature of the target site, acetyl-CoA carboxylase. Recent advances in our knowledge of acetyl-CoA carboxylases from sensitive and resistant plants has revealed some important facts. Dicotyledons, which are resistant, have a multi-enzyme complex type of carboxylase in their chloroplasts while grasses have a multifunctional protein. Both divisions of plants have two isoforms of the enzyme, the second being in the cytosol. Detailed study of multifunctional forms of acetyl-CoA carboxylases, which have different sensitivities to herbicides, suggests that herbicide resistance is correlated with cooperativity of herbicide binding to the native dimeric form of the carboxylase.
{"title":"Acetyl-CoA carboxylase : a graminicide target site","authors":"D. Herbert, K. A. Walker, L. Price, D. Cole, K. Pallett, S. M. Ridley, J. Harwood","doi":"10.1002/(SICI)1096-9063(199705)50:1<67::AID-PS552>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199705)50:1<67::AID-PS552>3.0.CO;2-#","url":null,"abstract":"Acetyl-CoA carboxylase catalyses the first committed step in fatty acid (and acyl lipid) formation. The enzyme has been shown to exert a high degree of flux control for lipid biosynthesis in leaves and, therefore, it is not surprising that chemicals which can inhibit it effectively are successful herbicides. These chemicals belong mainly to the cyclohexanedione and aryloxyphenoxypropionate classes and are graminicides. The reason for the selectivity of these herbicides towards grasses lies in the nature of the target site, acetyl-CoA carboxylase. Recent advances in our knowledge of acetyl-CoA carboxylases from sensitive and resistant plants has revealed some important facts. Dicotyledons, which are resistant, have a multi-enzyme complex type of carboxylase in their chloroplasts while grasses have a multifunctional protein. Both divisions of plants have two isoforms of the enzyme, the second being in the cytosol. Detailed study of multifunctional forms of acetyl-CoA carboxylases, which have different sensitivities to herbicides, suggests that herbicide resistance is correlated with cooperativity of herbicide binding to the native dimeric form of the carboxylase.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"165 1","pages":"67-71"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80415948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-12-01DOI: 10.1002/(SICI)1096-9063(199612)48:4<375::AID-PS501>3.0.CO;2-#
M. Schmitt, A. Turberg, M. Londershausen, A. Dorn
The calcium channel and the 'calcium release channel' of muscle membrane of the cockroach Periplaneta americana have been characterized. Biological assays with calcium channel blockers and ryanodine on different insects and acari revealed pronounced insecticidal effects with ryanodine, but not with calcium channel blockers, at concentrations between 0.1 and 300 μg ml -1 . Skeletal muscle membranes derived either from the tubular network or from the sarcoplasmatic reticulum of P. americana were characterized with respect to the binding of the dihydropyridine (DHP) [ 3 H]isradipine (PN 200-110), the phenylalkylamine [ 3 H]verapamil and the alkaloid [ 3 H]ryanodine. Preliminary binding studies with the benzothiazepine [ 3 H]diltiazem suggest a low-affinity binding site with a IC 50 value of 3.3 μM. All binding sites tested were sensitive to treatment with proteinase K. Optimal conditions for binding of the radioligand ryanodine revealed the highest specific binding at pH 8 and at calcium chloride concentrations between 100 and 500 μM. EGTA at 10 μM abolished 95% of the ryanodine binding. Binding studies with calcium channel binding sites revealed a pronounced effect of low Ca 2+ concentrations on specific isradipine binding, whereas verapamil and diltiazem binding were only reduced by the presence of 200 μM EGTA. With respect to high Ca 2+ concentrations, specific binding of diltiazem, isradipine and verapamil was reduced by 73, 40 and 20%, respectively, at 5 mM Ca 2+ . Radioligand binding experiments showed high-affinity binding sites for ryanodine and isradipine. K D values of 0.95 nM (B max = 550 fmol mg -1 protein) and 0.75 nM (B max = 213 fmol mg -1 protein) were determined respectively. A lower-affinity binding site was identified in binding studies with verapamil (K D = 7.4 nM and B max = 27 fmol mg -1 protein). [ 3 H]isradipine displacement studies with several dihydropyridines revealed the following ranking of affinity : nitrendipine > isradipine > Bay K8664 >> nicardipine. Displacement of [ 3 H]verapamil binding by effectors of the phenylalkylamine binding site showed that bepridil and S(-)verapamil had the highest affinities of the compounds tested followed by (±)verapamil, nor-methylverapamil and R(+)verapamil.
{"title":"Binding Sites for Ca2+‐Channel Effectors and Ryanodine in Periplaneta americana—Possible Targets for New Insecticides","authors":"M. Schmitt, A. Turberg, M. Londershausen, A. Dorn","doi":"10.1002/(SICI)1096-9063(199612)48:4<375::AID-PS501>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199612)48:4<375::AID-PS501>3.0.CO;2-#","url":null,"abstract":"The calcium channel and the 'calcium release channel' of muscle membrane of the cockroach Periplaneta americana have been characterized. Biological assays with calcium channel blockers and ryanodine on different insects and acari revealed pronounced insecticidal effects with ryanodine, but not with calcium channel blockers, at concentrations between 0.1 and 300 μg ml -1 . Skeletal muscle membranes derived either from the tubular network or from the sarcoplasmatic reticulum of P. americana were characterized with respect to the binding of the dihydropyridine (DHP) [ 3 H]isradipine (PN 200-110), the phenylalkylamine [ 3 H]verapamil and the alkaloid [ 3 H]ryanodine. Preliminary binding studies with the benzothiazepine [ 3 H]diltiazem suggest a low-affinity binding site with a IC 50 value of 3.3 μM. All binding sites tested were sensitive to treatment with proteinase K. Optimal conditions for binding of the radioligand ryanodine revealed the highest specific binding at pH 8 and at calcium chloride concentrations between 100 and 500 μM. EGTA at 10 μM abolished 95% of the ryanodine binding. Binding studies with calcium channel binding sites revealed a pronounced effect of low Ca 2+ concentrations on specific isradipine binding, whereas verapamil and diltiazem binding were only reduced by the presence of 200 μM EGTA. With respect to high Ca 2+ concentrations, specific binding of diltiazem, isradipine and verapamil was reduced by 73, 40 and 20%, respectively, at 5 mM Ca 2+ . Radioligand binding experiments showed high-affinity binding sites for ryanodine and isradipine. K D values of 0.95 nM (B max = 550 fmol mg -1 protein) and 0.75 nM (B max = 213 fmol mg -1 protein) were determined respectively. A lower-affinity binding site was identified in binding studies with verapamil (K D = 7.4 nM and B max = 27 fmol mg -1 protein). [ 3 H]isradipine displacement studies with several dihydropyridines revealed the following ranking of affinity : nitrendipine > isradipine > Bay K8664 >> nicardipine. Displacement of [ 3 H]verapamil binding by effectors of the phenylalkylamine binding site showed that bepridil and S(-)verapamil had the highest affinities of the compounds tested followed by (±)verapamil, nor-methylverapamil and R(+)verapamil.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"1 1","pages":"375-388"},"PeriodicalIF":0.0,"publicationDate":"1996-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89594068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1996-11-01DOI: 10.1002/(SICI)1096-9063(199611)48:3<205::AID-PS459>3.0.CO;2-#
B. T. Grayson, P. Price, David Walter
The effects of volume rate of application on the glasshouse performance of three recently developed crop protection agent/adjuvant combinations are discussed. High volume rates of application on easy-to-wet foliage, such as potato (Solanum tuberosum, L.) caused reduction of the adjuvant-enhanced performance of dimethomorph seen at low volume rates. These reductions were largely attributable to relatively lower spray retention with spray drop coalescence and run-off being observed, particularly at the higher adjuvant rates. On difficult-to-wet foliage (wheat, Triticum aestivum, L. ; oat, Avena sativa, L.) two different effects were seen. With a metconazole formulation/'Dobanol' 91-6 combination on wheat, no systematic changes in performance were observed with change in volume rate. With a flamprop-M-isopropyl formulation/'Dobanol' 25-7 combination, statistically significant increases in performance were seen with increasing volume rate. In both cases the observations can be explained as the result of a combination of interacting factors involving spray pattern, spray deposition and, by inference, foliar uptake of the crop protection agent, the proportions of which differed between the two cases. It is suggested that the effect of volume rate of application on performance of adjuvant-containing formulations is investigated on easy-to-wet foliage to determine the upper limits and on difficult-to-wet foliage to determine any variation in performance that may occur. Such information will guide the design of field trials and may aid interpretation of field results.
讨论了施量率对新开发的三种作物保护剂/佐剂组合温室性能的影响。在易于湿润的叶子上，如马铃薯(Solanum tuberosum, L.)上大量施用，会导致佐剂的减少，而在低体积用量下，则会增强吡虫啉的性能。这些减少在很大程度上是由于相对较低的喷雾滞留与喷雾滴聚结和流失量被观察到，特别是在较高的佐剂率。在难湿的叶片上(小麦，Triticum aestivum, L.;燕麦(Avena sativa, L.)有两种不同的效果。以甲康唑制剂/‘多巴诺’91-6组合施用小麦，其生产性能不随体积率的变化而发生系统性变化。使用flamprop- m -异丙基配方/'Dobanol' 25-7组合，随着体积率的增加，性能有统计学上的显著提高。在这两种情况下，观察结果都可以解释为多种相互作用因素的综合结果，这些因素包括喷雾方式、喷雾沉积以及由此推断的作物保护剂的叶面吸收，而叶面吸收的比例在两种情况下是不同的。建议在易湿叶子上研究体积率对含佐剂配方性能的影响，以确定其上限，在难湿叶子上研究体积率对可能发生的性能变化的影响。这些信息将指导田间试验的设计，并可能有助于田间试验结果的解释。
{"title":"Effect of the Volume Rate of Application on the Glasshouse Performance of Crop Protection Agent/Adjuvant Combinations","authors":"B. T. Grayson, P. Price, David Walter","doi":"10.1002/(SICI)1096-9063(199611)48:3<205::AID-PS459>3.0.CO;2-#","DOIUrl":"https://doi.org/10.1002/(SICI)1096-9063(199611)48:3<205::AID-PS459>3.0.CO;2-#","url":null,"abstract":"The effects of volume rate of application on the glasshouse performance of three recently developed crop protection agent/adjuvant combinations are discussed. High volume rates of application on easy-to-wet foliage, such as potato (Solanum tuberosum, L.) caused reduction of the adjuvant-enhanced performance of dimethomorph seen at low volume rates. These reductions were largely attributable to relatively lower spray retention with spray drop coalescence and run-off being observed, particularly at the higher adjuvant rates. On difficult-to-wet foliage (wheat, Triticum aestivum, L. ; oat, Avena sativa, L.) two different effects were seen. With a metconazole formulation/'Dobanol' 91-6 combination on wheat, no systematic changes in performance were observed with change in volume rate. With a flamprop-M-isopropyl formulation/'Dobanol' 25-7 combination, statistically significant increases in performance were seen with increasing volume rate. In both cases the observations can be explained as the result of a combination of interacting factors involving spray pattern, spray deposition and, by inference, foliar uptake of the crop protection agent, the proportions of which differed between the two cases. It is suggested that the effect of volume rate of application on performance of adjuvant-containing formulations is investigated on easy-to-wet foliage to determine the upper limits and on difficult-to-wet foliage to determine any variation in performance that may occur. Such information will guide the design of field trials and may aid interpretation of field results.","PeriodicalId":19985,"journal":{"name":"Pesticide Science","volume":"36 1","pages":"205-217"},"PeriodicalIF":0.0,"publicationDate":"1996-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75515927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：