Quantitative structure-activity relationship of synthetic pyrethroids and antibody activity / 中国免疫学杂志

Objective:To research on the immune recognition mechanism of synthetic pyrethroids and generic specific antibody.Methods:We studied on quantitative structure-activity relationship ( QSAR ) of synthetic pyrethroids and their analogs as well as antibody activity ( IC50:fifty percent inhibition concentration ) using stepwise multiple linear regression method.Based on calculating structure descriptors of synthetic pyrethroids and their analogs , two-demensional QSAR ( 2D-QSAR ) model was established.The main factors affecting antibody activity were screened using 2D-QSAR,and predictive ability of QSAR models were evaluated by the method of leave-one-out( LOO) cross-validation.Meanwhile, the structure parameters of synthetic pyrethroid fragments were calculated and then analyzed using partial least squares ( PLS) assay.And then hologram QSAR ( H-QSAR) model was constructed on molecular substructure and antibody activity.The fragments contribution to antibody activity were illustrated by encoding different colors.Results:Decision coefficent (R2) of 2D-QSAR model and HQSAR model were 0.920 and 0.917 individually,cross-validation coefficient ( Q2 ) of two QSAR models were 0.875 and 0.660 respectively ,which showed two models had good predictive abil-ity.The result from 2D-QSAR model was also obtained that smaller was hydrophobicity of pyrethroids , easier was recognized by antibody.In addition,the optimum HQSAR model was constructed after we tried many combinations of these parameters .The fragment size in optimum HQSAR model was between 4 to 10,a hologram length was 61,optimum principle component was 4,and the fragment type of B/C/Ch was selected.However ,the fingerprint encoded results of synthetic pyrethroids weren′t consistent completely with exper-imental IC50 values.Conclusion:Hydrophobicity of synthetic pyrethroids is the largest correlation factors in antibody recognization .

Study on the free radical scavenging activities and structurefunction relationships of glycoprotein from jellyfish (R.e) oralarms / 中国海洋药物

Objective To study the free radical scavenging activities and structure-function rela- tionship of glycoprotein(JF-Ⅲ)from jellyfish(R.e)oral-arms.Methods The scavenging ac- tivities on superoxide and hydroxyl radicals were estimated by chemiluminescence method, and the structure-function relationships were initial studied by chemical and enzymatic hy- drolysis methods.Results The free radical scavenging activities of the glycoprotein had sig- nificant dose-dependent relationship.The carbohydrate moiety and the protein moiety were both involved in scavenging activities on free radicals.N-linked sugar of JF-Ⅲplayed major roles in free radical scavenging activities,but O-linked sugar played minor roles.Conclusion JF-Ⅲhad strong free radical scavenging activities,which had close relations with its struc-ture.