Functional Characteristics of a Novel Chemosensory Protein in the Cotton Bollworm Helicoverpa armigera (Hübner)

A chemosensory protein named HarmCSP5 in cotton bollworm Helicoverpa armigera （Hvbner） was obtained from antennal eDNA libraries and expressed in Escherichia coll. The real time quantitative PCR （RT-qPCR） results indicated that HarmCSP5 gene was mainly expressed in male and female antennae but also expressed in female legs and wings. Competitive binding assays were performed to test the binding affinity of recombinant HarmCSP5 to 60 odor molecules including some cotton volatiles. The resules showed that HarmCSP5 showed strong binding abilities to 4-ehtylbenzaldehyde and 3,4-dimethlbenz aldehyde, whereas methyl phenylacetate, 2-decanone, 1-pentanol, carvenol, isobomeol, nerolidol, 2- nonanone and ethyl heptanoate have relatively weak binding affinity. Moreover, the predicted 3D model of HarmCSP5 consists of six α-helices located among residues 33-38 （αl）, 40-48 （α2）, 62-72 （α3）, 80-96 （α4）, 98-108 （α5）, and 116-119 （α6）, two pairs of disulfide bridges Cys49-Cys55, Cys75-Cys78. The two amino acid residues, Ile94 and Trpl01, may play crucial roles in HarmCSP5 binding with ligands and need further study for confirmation.

Molecular and in vitro biochemical assessment of chemosensory protein 10 from brown planthopper Nilaparvata lugens at acidic pH

Chemosensory proteins(CSPs)are important molecular components of the insect olfactory system,which are involved in capturing,binding,and transporting hydrophobic odour molecules across the sensillum in sensillar lymph in regulating insect behavior.This protein family(CSPs)is also involved in many other systems that are not linked to olfactory receptors in olfactory sensilla.The brown planthopper(BPH)is a monophagous pest of rice that causes damage by sucking phloem sap and transmitting a number of diseases caused by viruses.In this study,fluorescence competitive binding assay and fluorescence quenching assay at acidic p H were performed as well as homology modelling to describe the binding affinity of Nlug CSP10.Fluorescence competitive binding assay(FCBA)demonstrated that Nlug CSP10 bound strongly to nonadecane,farnesene,and 2-tridecanone at acidic p H.The results of FCBA indicated that Nlug CSP10 bound different ligands at the physiological p H(5.0)of the bulk sensillum lymph.Fluorescence quenching assay demonstrated that Nlug CSP10 generated a stable complex with 2-tridecanone,while two ligands nonadecane and farnesene collided due to molecular collisions.The interaction of selected ligands with the modelled structure of Nlug CSP10 was also analyzed,which found the key amino acids(Gln23,Gln24,Gln25,Asn27,Met33,Ser34,Ile35,Tyr36,Asn42,Met43,Val45,Asn46,Asn93,Arg96,Ala97,Lys99,and Ala100)in Nlug CSP10 that were involved in binding of volatile compounds.The present study contributes to the binding profile of Nlug CSP10 that promotes the development of behaviorally active ligands based on BPH olfactory system.

三种检测24小时尿游离皮质醇方法的比较

应用化学发光免疫测定法 (CLIA)和竞争性蛋白结合分析法 (CPBA)检测 2 4h尿游离皮质醇 (UFC)水平 ,比较方法的相关性、精密度及特异性。拟用CLIA替代CPBA检测UFC。采用CLIA提取法与CLIA未提取法和CPBA法检测 5 3名正常人 ,13例未经治疗的库欣综合征患者和 92例肥胖患者及 37例口服类固醇激素药患者的 2 4hUFC水平。对其结果进行相关性比较 ,并做重复性试验 ,同时进行了七种类固醇激素的交叉试验 ,以比较三种方法的精密度和特异性。CLIA提取法与CPBA法相比较 ,r =0 .814 ,P <0 .0 0 0 1;CLIA未提取法与CPBA法相比较 ,r =0 .70 6 ,P <0 .0 0 0 1;CLIA提取法和CLIA未提取法相比较 ,r =0 .90 1,P <0 .0 0 0 1。交叉试验显示 :除皮质醇外 ,强的松龙在CPBA法、CLIA提取法和CLIA未提取法中 ,均干扰UFC测定 ,其交叉百分率分别为 19.0 %、15 .4 %及 2 4 .9% ,高于其它五种类固醇激素 ,而后五种激素对UFC的测定干扰不大。两种CLIA法的批内和批间变异系数均小于CPBA法 ,而且均与CPBA法有很好的相关性。由于CLIA提取法的精密度和特异性均优于CPBA法和CLIA未提取法 ,本文建议用CLIA提取法代替CPBA法。