[Sample pretreatment methods of pesticide residues in Panax notoginseng of Chinese traditional medicine].

Two sample pretreatment methods of pesticide residues in Panax notoginseng of Chinese traditional medicine were developed. For Method I, the residues were extracted from homogenized tissue with n-hexane-dichloromethane (6:4) by means of ultrasonication, the crude extract was purified by an Envi-carb/NH2 solid-phase extraction (SPE) column. For Method II, matrix solid-phase dispersion (MSPD) technique was used for extracting and cleaning up. The eluates were concentrated by rotary evaporation, and then were redissolved in dichloromethane prior to GC-MS determination. The determination was performed in selected ion monitoring (SIM) mode with the external calibration for quantitative analysis. Under the optimal conditions, the results indicated that the methods are easier and faster, the recoveries of method I for the spiked standards at concentration of 0.01, 0.5, and 2.0 mg x kg(-1) were 81.90%-102.10% with the relative standard deviations (RSDs) of 3.60%-7.10%. The recoveries of method II were 96.26%-104.20% with the RSDs of 3.52%-7.94%. The detection limits (S/N) for residues of pesticides were in the range of 0.48-1.34 ng x g(-1). The results indicated that these multiresidue analysis methods can meet the requirements for determination of residue pesticides and can be appropriate for trace analysis of residue pesticides in Panax notoginseng.

[Comparative study on trace elements in Elsholtzia bodineri Vaniot. from Honghe by FAAS].

In the present paper, the authors prepared all the samples by the same method, and optimized the work conditions for flame qtomic absorption spectrometry. FAAS was applied to determine the trace elements, such as Pb, Cr, Cd, Cu, Zn, Hg, Se etc, in Elsholtzia bodineri Vaniot. from Mengzi, Shiping, Mile and Jianshui located in Honghe state. The method is simple, rapid and accurate, and allows simultaneous determination of many elements. The recoveries were in the range of 98.7%-116.4%, and RSD was 0.07%-1.69%. The contents of Pb, Cd and Hg were 53.47, 6.03 and 7.68 microg x g(-1), respectively, in the sample from Jianshui, and were higher than those from other areas. The content of Mn was the highest, and was higher in Mengzi than in other areas, and the average content in the four samples was 913.48 microg x g(-1), which was higher than the content in the soil. Fe is the semi-microelement whose average content in Elsholtzia bodineri Vaniot. from Honghe was 688.46 microg x g(-1), the high-to-low content sequence of Fe in terms of location was Mengzi, Mile, Shiping and Jianshui. The average content of Zn was 116.64 microg x g(-1), and the highest one was from Shiping. But we did not obtain the data of Se in the Elsholtzia bodineri Vaniot. from Honghe state by AAS, and did not detect Hg in samples from Shiping and Mile. The content of the detected elements in Mengzi's sample had the sequence as follows; Mn > Fe > Zn > Pb > Cu > Cr > Cd > Hg>Se, while the sequence was Mn > Fe > Zn > Pb > Cu > Hg > Cd > Cr > Se in the sample of Jianshui, Mn > Fe > Z n >Pb > Cu > Cd > Cr > Hg > Se in Shiping, and Fe > Mn > Zn > Pb > Cu > Cd > Cr > Hg > Se in Mile. The results show that the content of the trace elements is high, especially, Mn, Fe and Zn, in Elsholtzia bodineri Vaniot. in Honghe. Therefore, Elsholtzia bodineri Vaniot., which can be used as drug or beverage, is worth exploitation.

Selection of active ScFv to G-protein-coupled receptor CCR5 using surface antigen-mimicking peptides.

This study describes the use of cyclic peptides for use in the selection of single-chain (ScFv) antibodies specific for the HIV-1 coreceptor CCR5, a representative G-protein-coupled receptor (GPCR). A tandem ligation strategy was developed for preparing biotinylated cyclic peptides, first through an orthogonal end-to-end ligation and then a chemoselective ligation with functionalized biotin. Cyclic peptides mimicking the extracellular loops of CCR5 and their unconstrained counterparts were then used for solution-phase selection of ScFv antibodies from a phage display antibody library. Antibodies reactive with CCR5 on cells were detected using a homogeneous high throughput assay. Of 19 isolated ScFv antibodies that bound to CCR5+ cells, three inhibited CCR5-mediated but not CXCR4-mediated HIV infection. Only ScFvs selected by binding to cyclic constrained peptides exhibited inhibitory activity. Our results demonstrate that surface-antigen mimetics of a GPCR are effective tools for selecting active, site-specific ScFv antibodies that hold promise as immunological reagents and therapeutics.