The hazelnut weevil(Curculio dieckmanni Faust.)is a major pest of Asian hazel(Corylus heterophylla Fisch.)in China.Dead hazelnut weevil larvae were examined and the associated pathogenic bacterium was identifi ed as S...The hazelnut weevil(Curculio dieckmanni Faust.)is a major pest of Asian hazel(Corylus heterophylla Fisch.)in China.Dead hazelnut weevil larvae were examined and the associated pathogenic bacterium was identifi ed as Serratia marcescens Bizio.This signifi cantly shortened the lifespan of hazelnut weevil.Larval weight was reduced as a function of S.marcescens concentration and exposure time.The structure of infected midgut cells was altered,with necrosis of the wall tissues and many cells becoming dislodged,creating cavities.The S.marcencens strain inhibited digestive enzyme activity and protective enzymes in the midgut of adult hazelnut weevil.Inhibition on S.marcencens strain increased with treatment time.S.marcescens directly destroyed the midgut cells and interfered with digestive and protective enzymes.This decreased the food intake and increased mortality of hazelnut weevil.S.marcescens appears to be an eff ective bacterium for the control of hazelnut weevil but requires further study,including biological formulation development and fi eld application.展开更多
To increase the adsorption capacity of the Corylus heterophylla Fisch（HS） for Pb2＋, HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified us...To increase the adsorption capacity of the Corylus heterophylla Fisch（HS） for Pb2＋, HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified using mercaptoacetic acid. The SHS modified with mercaptoacetic acid（MHS） was characterized using FTIR, SEM, and XPS. The results indicated that the --SH group was present on MHS, and after Pb2＋ adsorption, the absorption value of the characteristic peak of the --SH group decreased. The adsorption and desorption properties of this func- tionalized material were investigated as well as the influences of parameters, such as pH value, type of desorption reagent, dosage, flow rate and maximum sample volume. The Pb2~ adsorption of MI-IS reached a maximum with pH〉5. The experimental data of Pb2＋ adsorption using MHS were fitted using the Langmuir isothermal adsorption model, and a maximum adsorption capacity of 61.54 mg/g was obtained. This was much higher than the adsorption capacity of SHS before modification with the thiol group. After adsorption, MHS was desorbed using a 0.2 mol/L HC1 solution, and the percent of desorption was higher than 99%. MHS was used as a solid-phase extractant in the analysis and determination of Pb2＋ content in food and water samples, and the enrichment times achieved 150-fold.展开更多
基金the National Key Research and Development project of China(2016YFC0500308)Special Project for Double First-Class-Cultivation of Innovative Talents(000/41113102)+1 种基金the Natural Science Foundation of Heilongjiang Scientifi c Committee(C2018055)the Application Research Project of Heilongjiang Provincial Forest Industry Administration(sgzjY2014004).
文摘The hazelnut weevil(Curculio dieckmanni Faust.)is a major pest of Asian hazel(Corylus heterophylla Fisch.)in China.Dead hazelnut weevil larvae were examined and the associated pathogenic bacterium was identifi ed as Serratia marcescens Bizio.This signifi cantly shortened the lifespan of hazelnut weevil.Larval weight was reduced as a function of S.marcescens concentration and exposure time.The structure of infected midgut cells was altered,with necrosis of the wall tissues and many cells becoming dislodged,creating cavities.The S.marcencens strain inhibited digestive enzyme activity and protective enzymes in the midgut of adult hazelnut weevil.Inhibition on S.marcencens strain increased with treatment time.S.marcescens directly destroyed the midgut cells and interfered with digestive and protective enzymes.This decreased the food intake and increased mortality of hazelnut weevil.S.marcescens appears to be an eff ective bacterium for the control of hazelnut weevil but requires further study,including biological formulation development and fi eld application.
文摘To increase the adsorption capacity of the Corylus heterophylla Fisch（HS） for Pb2＋, HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified using mercaptoacetic acid. The SHS modified with mercaptoacetic acid（MHS） was characterized using FTIR, SEM, and XPS. The results indicated that the --SH group was present on MHS, and after Pb2＋ adsorption, the absorption value of the characteristic peak of the --SH group decreased. The adsorption and desorption properties of this func- tionalized material were investigated as well as the influences of parameters, such as pH value, type of desorption reagent, dosage, flow rate and maximum sample volume. The Pb2~ adsorption of MI-IS reached a maximum with pH〉5. The experimental data of Pb2＋ adsorption using MHS were fitted using the Langmuir isothermal adsorption model, and a maximum adsorption capacity of 61.54 mg/g was obtained. This was much higher than the adsorption capacity of SHS before modification with the thiol group. After adsorption, MHS was desorbed using a 0.2 mol/L HC1 solution, and the percent of desorption was higher than 99%. MHS was used as a solid-phase extractant in the analysis and determination of Pb2＋ content in food and water samples, and the enrichment times achieved 150-fold.
