Synergistic actions for mixtures of abamectin with other insecticides in some insect pests were evaluated, and the possible synergistic mechanism was studied by the comparison in toxicity and cuticular penetration of ...Synergistic actions for mixtures of abamectin with other insecticides in some insect pests were evaluated, and the possible synergistic mechanism was studied by the comparison in toxicity and cuticular penetration of abamectin between with and without other insecticides or synergists in Helicoverpa armigera larvae. The results of bioassay showed that horticultural mineral oil (HMO), hexaflumuron, chlorpyrifos, and some other insecticides were synergistic to abamectin with 152.0-420.0 of co-toxicity coefficient(CTC) in some agricultural insect pests. In topical application tests, HMO or piperonyl butoxide (PBO) increased the toxicity of abamectin in larvae of H. armigera, but the mortality was not affected by s,s,s-tributylphorotrithioate (DEF) and triphenylphosphate (TPP). The synergistic action of HMO was obviously higher than PBO, and when treated simultaneously with abamectin, HMO gave a more significant synergism than if treated 2 hours ahead. The highest synergistic effect (SE) was found in the mixture of ‘abamectin+HMO (1:206)'. The mortality did not increase or the toxicity drop, when a synergist or HMO was added into the mixture of ‘abamectin+HMO' or ‘abamectin+synergist', respectively. Results from the isotope tracing experiments showed that HMO significantly enhanced the penetration of ^3H-abamectin through the cuticle of H.armigera larvae, which resulted in the synergism of the mixture. The cuticular penetration of ^3H-abamectin was not accumulatively affected by chlorpyrifos, nor by hexaflumuron,though there was an inhibition within 30 seconds or 1 hour after treated by these two chemicals respectively. Results suggested that the synergism of abamectin mixed with hexaflumuron or chlorpyrifos might be related to inhibition of metabolic enzymes or target sites in the larvae.展开更多
bstract A chemometric study using pattern recognition technology was carried out to characterize the geographic origins of the brown planthopper, Nilaparvata lugens. The concentrations of 23 trace elements （Mn, Mo, C...bstract A chemometric study using pattern recognition technology was carried out to characterize the geographic origins of the brown planthopper, Nilaparvata lugens. The concentrations of 23 trace elements （Mn, Mo, Cd, Ce, V, Th, Cs, Be, T1, Fe, Nd, Pr, Se, Tm, Lu, Eu, Ho, Br, Dy, Gd, U, Sm and Er） in 53 samples from seven regions in southern China were determined using inductively coupled plasma mass spectrometry. The data obtained were successively evaluated using a multivariate statistical approach, namely, linear discriminant analysis, which allowed classification and discrimination of the N. lugens samples from Fuqing, Shaoguan, Hepu, Yongfu, Hengnan, Wan-an and Yongkang with high accuracy and a clear separation among the seven regions. The results show that pattern identification on the basis of trace elements in the bodies ofN. lugens is feasible for determining the geographic origins of individuals.展开更多
The piggyBac transposon has been long used to integrate foreign DNA into insect genomes.However,undesirable transgene expression can result from random insertions into the genome.In this study,the efficiency of chimer...The piggyBac transposon has been long used to integrate foreign DNA into insect genomes.However,undesirable transgene expression can result from random insertions into the genome.In this study,the efficiency of chimeric Gal4-piggyBac transposase in directing integration onto a DNA target plasmid was evaluated in cultured silkworm Bombyx mori Bm-12 and fruit fly Drosophila Schneider 2(S2) cells.The Gal4-piggyBac transposase has a Gal4 DNA-binding domain(DBD),and the target plasmid has upstream activating sequences(UAS) to which the Gal4 DBD can bind with high affinity.The results indicate that,in the Bm-12 and S2 cells,transpositional activity of Gal4-piggyBac transposase was increased by 4.0 and 7.5 times,respectively,compared to controls,where Gal4-UAS interaction was absent.Moreover,the Gal4-piggyBac transposase had the ability of directing piggyBac element integration to certain sites of the target plasmid,although the target-directing specificity was not as high as expected.The chimeric piggyBac transposase has the potential for use in site-directed transgenesis and gene function research in B.mori.展开更多
文摘Synergistic actions for mixtures of abamectin with other insecticides in some insect pests were evaluated, and the possible synergistic mechanism was studied by the comparison in toxicity and cuticular penetration of abamectin between with and without other insecticides or synergists in Helicoverpa armigera larvae. The results of bioassay showed that horticultural mineral oil (HMO), hexaflumuron, chlorpyrifos, and some other insecticides were synergistic to abamectin with 152.0-420.0 of co-toxicity coefficient(CTC) in some agricultural insect pests. In topical application tests, HMO or piperonyl butoxide (PBO) increased the toxicity of abamectin in larvae of H. armigera, but the mortality was not affected by s,s,s-tributylphorotrithioate (DEF) and triphenylphosphate (TPP). The synergistic action of HMO was obviously higher than PBO, and when treated simultaneously with abamectin, HMO gave a more significant synergism than if treated 2 hours ahead. The highest synergistic effect (SE) was found in the mixture of ‘abamectin+HMO (1:206)'. The mortality did not increase or the toxicity drop, when a synergist or HMO was added into the mixture of ‘abamectin+HMO' or ‘abamectin+synergist', respectively. Results from the isotope tracing experiments showed that HMO significantly enhanced the penetration of ^3H-abamectin through the cuticle of H.armigera larvae, which resulted in the synergism of the mixture. The cuticular penetration of ^3H-abamectin was not accumulatively affected by chlorpyrifos, nor by hexaflumuron,though there was an inhibition within 30 seconds or 1 hour after treated by these two chemicals respectively. Results suggested that the synergism of abamectin mixed with hexaflumuron or chlorpyrifos might be related to inhibition of metabolic enzymes or target sites in the larvae.
文摘bstract A chemometric study using pattern recognition technology was carried out to characterize the geographic origins of the brown planthopper, Nilaparvata lugens. The concentrations of 23 trace elements （Mn, Mo, Cd, Ce, V, Th, Cs, Be, T1, Fe, Nd, Pr, Se, Tm, Lu, Eu, Ho, Br, Dy, Gd, U, Sm and Er） in 53 samples from seven regions in southern China were determined using inductively coupled plasma mass spectrometry. The data obtained were successively evaluated using a multivariate statistical approach, namely, linear discriminant analysis, which allowed classification and discrimination of the N. lugens samples from Fuqing, Shaoguan, Hepu, Yongfu, Hengnan, Wan-an and Yongkang with high accuracy and a clear separation among the seven regions. The results show that pattern identification on the basis of trace elements in the bodies ofN. lugens is feasible for determining the geographic origins of individuals.
基金supported by the National Basic Research Program (973) of China (No. 2009CB119200)the Natural Science Foundation of Zhejiang Province (No. Y304122),China
文摘The piggyBac transposon has been long used to integrate foreign DNA into insect genomes.However,undesirable transgene expression can result from random insertions into the genome.In this study,the efficiency of chimeric Gal4-piggyBac transposase in directing integration onto a DNA target plasmid was evaluated in cultured silkworm Bombyx mori Bm-12 and fruit fly Drosophila Schneider 2(S2) cells.The Gal4-piggyBac transposase has a Gal4 DNA-binding domain(DBD),and the target plasmid has upstream activating sequences(UAS) to which the Gal4 DBD can bind with high affinity.The results indicate that,in the Bm-12 and S2 cells,transpositional activity of Gal4-piggyBac transposase was increased by 4.0 and 7.5 times,respectively,compared to controls,where Gal4-UAS interaction was absent.Moreover,the Gal4-piggyBac transposase had the ability of directing piggyBac element integration to certain sites of the target plasmid,although the target-directing specificity was not as high as expected.The chimeric piggyBac transposase has the potential for use in site-directed transgenesis and gene function research in B.mori.
