试验结果表明,随着三疣梭子蟹幼体的发育,其半致死质量浓度以及安全质量浓度呈上升趋势。三疣梭子蟹Ⅰ期溞状幼体24 h LC50和48 h LC50分别为0.0095 mg/L和0.0082 mg/L,安全质量浓度为0.0018 mg/L;三疣梭子蟹Ⅱ期溞状幼体24 h LC50和48 ...试验结果表明,随着三疣梭子蟹幼体的发育,其半致死质量浓度以及安全质量浓度呈上升趋势。三疣梭子蟹Ⅰ期溞状幼体24 h LC50和48 h LC50分别为0.0095 mg/L和0.0082 mg/L,安全质量浓度为0.0018 mg/L;三疣梭子蟹Ⅱ期溞状幼体24 h LC50和48 h LC50分别为0.019 mg/L和0.010 mg/L,安全质量浓度为0.0038 mg/L;三疣梭子蟹Ⅳ期溞状幼体24 h LC50和48 h LC50分别为0.085 mg/L和0.047 mg/L,安全质量浓度为0.0043 mg/L;三疣梭子蟹大眼幼体24 h LC50和48 h LC50分别为0.085mg/L和0.050 mg/L,安全质量浓度为0.0052 mg/L。展开更多
Insecticidal effects of 4-hexylresorcinol, a phenoloxidase （PO） inhibitor, were determined on Hyphantria cunea （Drury） under laboratory conditions. The LC50 for the 15- d-old larvae was estimated to be 2.95 g/L af...Insecticidal effects of 4-hexylresorcinol, a phenoloxidase （PO） inhibitor, were determined on Hyphantria cunea （Drury） under laboratory conditions. The LC50 for the 15- d-old larvae was estimated to be 2.95 g/L after 96 h exposure. The activities of glutathione S-transferase （GST） and PO showed a decrease in larvae treated with 4-hexylresorcinol, and the IC50 of GST and PO were estimated to be 0.8 and 0.43 g/L, respectively, 24 h after treatment. The PO from the hemolymph of fall webworm was purified by ammonium sulfate precipitation, gel-filtration, and ion-exchange chromatography, and then enzymatic characteristics and the mechanism of inhibition were determined using L-dihydroxyphenylalanine （L-DOPA） as the substrate. The purified PO showed a single band on SDS-PAGE with a molecular weight of about 70 kDa. The optimum pH for PO activity was observed at pH 7.0, optimum temperature was found to be 45 ℃, and PO activity was strongly inhibited by Zn2＋. IC50 values were estimated to be 8.2, 19.14, and 24.04/zmol/L for 4-hexylresorsinol, kojic acid, and quercetin, respectively. The inhibitory potencies （i.e., 150 of each compound/Is0 of 4-hexylresorcinol） ofkojic acid and quercetin on H. cunea PO were estimated to be 1.87 and 2.89, respectively. 4-hexylresorcinol was determined to be a competitive inhibitor, and kojic acid and quercetin were determined to be mixed inhibitors. PO is one of the most important enzymes in an insect＇s immune system, and the use ofPO inhibitors seems to be a promising approach for pest control due to their potential safety for humans.展开更多
文摘试验结果表明,随着三疣梭子蟹幼体的发育,其半致死质量浓度以及安全质量浓度呈上升趋势。三疣梭子蟹Ⅰ期溞状幼体24 h LC50和48 h LC50分别为0.0095 mg/L和0.0082 mg/L,安全质量浓度为0.0018 mg/L;三疣梭子蟹Ⅱ期溞状幼体24 h LC50和48 h LC50分别为0.019 mg/L和0.010 mg/L,安全质量浓度为0.0038 mg/L;三疣梭子蟹Ⅳ期溞状幼体24 h LC50和48 h LC50分别为0.085 mg/L和0.047 mg/L,安全质量浓度为0.0043 mg/L;三疣梭子蟹大眼幼体24 h LC50和48 h LC50分别为0.085mg/L和0.050 mg/L,安全质量浓度为0.0052 mg/L。
文摘Insecticidal effects of 4-hexylresorcinol, a phenoloxidase （PO） inhibitor, were determined on Hyphantria cunea （Drury） under laboratory conditions. The LC50 for the 15- d-old larvae was estimated to be 2.95 g/L after 96 h exposure. The activities of glutathione S-transferase （GST） and PO showed a decrease in larvae treated with 4-hexylresorcinol, and the IC50 of GST and PO were estimated to be 0.8 and 0.43 g/L, respectively, 24 h after treatment. The PO from the hemolymph of fall webworm was purified by ammonium sulfate precipitation, gel-filtration, and ion-exchange chromatography, and then enzymatic characteristics and the mechanism of inhibition were determined using L-dihydroxyphenylalanine （L-DOPA） as the substrate. The purified PO showed a single band on SDS-PAGE with a molecular weight of about 70 kDa. The optimum pH for PO activity was observed at pH 7.0, optimum temperature was found to be 45 ℃, and PO activity was strongly inhibited by Zn2＋. IC50 values were estimated to be 8.2, 19.14, and 24.04/zmol/L for 4-hexylresorsinol, kojic acid, and quercetin, respectively. The inhibitory potencies （i.e., 150 of each compound/Is0 of 4-hexylresorcinol） ofkojic acid and quercetin on H. cunea PO were estimated to be 1.87 and 2.89, respectively. 4-hexylresorcinol was determined to be a competitive inhibitor, and kojic acid and quercetin were determined to be mixed inhibitors. PO is one of the most important enzymes in an insect＇s immune system, and the use ofPO inhibitors seems to be a promising approach for pest control due to their potential safety for humans.
