5-Aminolevulinic acid （ALA）, a major photosensitivity insecticide, has attracted increasing attention as a new type of highly efficient, environmental friendly pesticide to be used to control the pest. To examine wh...5-Aminolevulinic acid （ALA）, a major photosensitivity insecticide, has attracted increasing attention as a new type of highly efficient, environmental friendly pesticide to be used to control the pest. To examine whether or not ALA acts effectively to grasshopper, Oxya chinensis and elucidate the detoxification mechanism of ALA, the susceptibility to ALA was assessed in O. chinensis and two major metabolic detoxification enzymes including glutathione S-transferases （GSTs） and general esterases （ESTs）-specific activities were compared in different development stages and different body sections of O. chinensis treated by ALA and the control. The results showed that the ALA exhibited obvious toxicity to the grasshopper in different development stages. In the low-dose treatment （0.0597 mmol L-1）, the mortalities of O. chinensis reached a significant level （55.5% in the 1st instar nymphs, 61.4% in the 2nd instar nymphs, 71.4% in the 3rd instar nymphs, and 64.4% in the 4th instar nymphs. But, there was no dose-dependent toxic effect. Thereby, we proposed that ALA has the potential for acting as photosensitivity insecticide for controlling O. chinensis. GSTs activity assays using CDNB and DCNB as substrates indicated that the thorax and abdomen of the different instar nymphs treated by ALA showed 1.52-5.56 fold significantly increased GSTs activities compared with the control. However, for the ESTs-specific activity assay, there was no significant difference between O. chinensis treated by ALA and the control within different instar nymphs, when a-NA, a-NB and b-NA were used as substrates. Therefore, GSTs-mediated metabolic detoxification as evidenced by significantly increased GSTs activities might contribute to protect against oxidative damage and oxidative stress by ALA in O. chinensis.展开更多
We evaluate comparative toxicity of malathion in the two populations of the grasshopper Oxya chinensis, collected from Daixian and Fanshi of Shanxi province, China. General esterases and acetylcholinesterase （ACHE） ...We evaluate comparative toxicity of malathion in the two populations of the grasshopper Oxya chinensis, collected from Daixian and Fanshi of Shanxi province, China. General esterases and acetylcholinesterase （ACHE） from the two populations were characterized and compared. LD50 of the Daixian population （7.58 μg/g body weight） was 2.02-fold higher than that of the Fanshi population （3.75μg/g body weight）. General esterase-specific activities in the Daixian population were 1.91,130 and 1.85-fold higher than those in the Fanshi population, when α-NA, α-NB and β-NA were used as a substrate, respectively. Kinetic studies of general esterase showed that Vmax values of general esterases hydrolyzing α-NA,α-NB and β-NA in the Daixian population were 2.15-, 1.12-, and 1.47-fold, respectively, higher than those in the Fanshi population. The AChE activity of the Fanshi population was 1.54-fold higher than that of the Daixian population. Kinetic analysis of AChE showed that significant differences were presented between the two populations in the Km values; and the Vmax value in the Fanshi population was higher than that in the Daixian population. Inhibition studies of AChE indicated that AChE from the Daixian population was 2.56-, 2.80-, and 2.29-fold less sensitive to inhibition by paraoxon, chlorpyrifos-oxon, and demeton-S-methyl, respectively, than that from the Fanshi population. These biochemical characterizations of general esterases and AChE were consistent with malathion bioassay in the two populations. It is inferred that the reduced sensitivity of altered AChE and increased general esterase activities play an important role in the differences of insusceptibility of Oxya chinensis to malathion between the two populations.展开更多
基金supported by the National Natural Science Foundation of China (30870302 and 30970410)the Youth Foundation of Shanxi Province, China (2007021030)the Research Fund for the Doctoral Program of Higher Education of China (20101401120008)
文摘5-Aminolevulinic acid （ALA）, a major photosensitivity insecticide, has attracted increasing attention as a new type of highly efficient, environmental friendly pesticide to be used to control the pest. To examine whether or not ALA acts effectively to grasshopper, Oxya chinensis and elucidate the detoxification mechanism of ALA, the susceptibility to ALA was assessed in O. chinensis and two major metabolic detoxification enzymes including glutathione S-transferases （GSTs） and general esterases （ESTs）-specific activities were compared in different development stages and different body sections of O. chinensis treated by ALA and the control. The results showed that the ALA exhibited obvious toxicity to the grasshopper in different development stages. In the low-dose treatment （0.0597 mmol L-1）, the mortalities of O. chinensis reached a significant level （55.5% in the 1st instar nymphs, 61.4% in the 2nd instar nymphs, 71.4% in the 3rd instar nymphs, and 64.4% in the 4th instar nymphs. But, there was no dose-dependent toxic effect. Thereby, we proposed that ALA has the potential for acting as photosensitivity insecticide for controlling O. chinensis. GSTs activity assays using CDNB and DCNB as substrates indicated that the thorax and abdomen of the different instar nymphs treated by ALA showed 1.52-5.56 fold significantly increased GSTs activities compared with the control. However, for the ESTs-specific activity assay, there was no significant difference between O. chinensis treated by ALA and the control within different instar nymphs, when a-NA, a-NB and b-NA were used as substrates. Therefore, GSTs-mediated metabolic detoxification as evidenced by significantly increased GSTs activities might contribute to protect against oxidative damage and oxidative stress by ALA in O. chinensis.
文摘We evaluate comparative toxicity of malathion in the two populations of the grasshopper Oxya chinensis, collected from Daixian and Fanshi of Shanxi province, China. General esterases and acetylcholinesterase （ACHE） from the two populations were characterized and compared. LD50 of the Daixian population （7.58 μg/g body weight） was 2.02-fold higher than that of the Fanshi population （3.75μg/g body weight）. General esterase-specific activities in the Daixian population were 1.91,130 and 1.85-fold higher than those in the Fanshi population, when α-NA, α-NB and β-NA were used as a substrate, respectively. Kinetic studies of general esterase showed that Vmax values of general esterases hydrolyzing α-NA,α-NB and β-NA in the Daixian population were 2.15-, 1.12-, and 1.47-fold, respectively, higher than those in the Fanshi population. The AChE activity of the Fanshi population was 1.54-fold higher than that of the Daixian population. Kinetic analysis of AChE showed that significant differences were presented between the two populations in the Km values; and the Vmax value in the Fanshi population was higher than that in the Daixian population. Inhibition studies of AChE indicated that AChE from the Daixian population was 2.56-, 2.80-, and 2.29-fold less sensitive to inhibition by paraoxon, chlorpyrifos-oxon, and demeton-S-methyl, respectively, than that from the Fanshi population. These biochemical characterizations of general esterases and AChE were consistent with malathion bioassay in the two populations. It is inferred that the reduced sensitivity of altered AChE and increased general esterase activities play an important role in the differences of insusceptibility of Oxya chinensis to malathion between the two populations.
