Determination of deoxyribonucleic acids by a resonance light scattering technique and its application

For the first time, acetamiprid has been used to determine nucleic acid (DNA) using the resonance light scattering (RLS). The RLS of acetamiprid was greatly enhanced by DNA in the range of pH 1.6-1.8. A RLS peak at 313 nm was found, and the enhanced intensity of RLS at this wavelength was proportional to the concentration of DNA. The linear range of the calibration curve was 0-11.0 microg ml(-1) with the detection limit of 20 ng ml(-1). The nucleic acids in synthetic sample and in rice seedling extraction were determined satisfactorily. The interaction mechanism of acetamiprid and DNA is discussed. Mechanism studies show that the enhanced RLS is due to the aggregation of acetamiprid in the presence of DNA.     

Insight into Seasonal Change of Phytochemicals,Antioxidant, and Anti-Aging Activities of Root Bark of Paeonia suffruticosa (Cortex Moutan) Combined with Multivariate Statistical Analysis

Chemical compositions, antioxidants, and anti-aging activities of Cortex Moutan (CM), from different collection periods and different producing areas, were measured and compared in order to obtain excellent CM extracts. The bioactivities of CM extracts were examined by an in vitro antioxidant method and a UVB irradiated human dermal fibroblast (HDF) model. Phytochemical properties were obtained from ultra-fast liquid chromatography quadrupole time-of-flight mass spectrometry (UFLC-Q-TOF-MS) prior to the multivariate statistical analysis. As for the results, the extracts of Heze CM (HZCM) and Luoyang CM (LYCM) collected in June had better in vitro antioxidant activities, significantly increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and reduced the content of malondialdehyde (MDA), compared to other CM extracts. HZCM and LYCM extracts could upregulate the relative expression of SOD and GSH-Px mRNA. The extract of HZCM collected in June could significantly repress the production of matrix metalloproteinase 1 (MMP-1) and improve the production of procollagen type I (PCOL)-I in UVB irradiated HDF. In total, 50 compounds, including 17 monoterpenoids, 19 flavonoids, 13 phenols, and 1 amino acid were identified or tentatively identified in the CM extracts. Gallic acid, p-hydroxybenzoic acid, oxypaeoniflorin, paeoniflorin, 1,2,3,4,6-O-pentagalloyl glucose, and paeonol were predominant compounds in the CM extracts. Taken together, CM collected from April to September had better antioxidant and anti-aging effects for external usage.     

新型苯并噻唑类探针的合成及其对S2-的荧光和比色检测

本文设计合成了一种基于激发态分子内质子转移(ESIPT)机理的苯并噻唑类荧光探针TZ-1,并对其结构进行了表征。实验结果表明,在体积比1∶1的DMSO/PBS(10mmol/L,pH=7.4)溶液中,探针TZ-1具有高选择性并可在3s内实现荧光"off-on"(在365nm紫外灯照射下,由无荧光变成橙色荧光)识别S~(2-),检测限为81μmol/L,pH适用范围为6～12;此外,加入S~(2-)后探针TZ-1的DMSO/PBS溶液由无色变为浅黄色,通过裸眼即可识别S~(2-)。     

Enantioselective synthesis of quaternary stereogenic centers through catalytic asymmetric addition of dimethylzinc to α-ketoesters with chiral cis-cyclopropane-based amide alcohol as ligand

A new amino alcohol with a chiral cyclopropane backbone has been developed and used in the catalytic asymmetric diethylzinc addition to various types of α-ketoesters. This cyclopropane-based chiral amino alcohol shows moderate enantioselectivity in the addition of organozinc to α-ketoesters. For dimethylzinc addition to α-ketoesters, up to 81% ee are obtained, respectively.     

末端炔与亚胺及衍生物的不对称加成反应研究进展

总结了近年来关于末端炔与亚胺及衍生物的不对称加成反应的研究进展,包括小分子均相催化体系与固载化的手性催化剂.其中小分子均相催化体系主要有:Pybox-铜、手性二胺-铜、Quinap-铜、Pinap-铜、磺酰胺亚胺-铜、二肽类-镐、氨基醇-锌等.另外,还讨论了末端炔、醛与胺的多组分反应的研究.     

Determination of carbofuran by the quenching effect on resonance light scattering and its application to water and vegetable samples

A new method for the determination of carbofuran (CF) with DNA by a resonance light scattering (RLS) technique was developed. The intensity of RLS (I _RLS) of DNA–HCl system was significantly quenched in presence of CF. A RLS peak at 315.6 nm was found, and the quenched intensity of RLS was proportional to the concentration of CF. The linear range of the calibration curve was ≈0.02–2.0 µg mL^?1 and the detection limit (S/N = 3) 7 ng mL^?1. The CF in river water, cucumbers and rice samples was determined. The recovery rates were in the range of 90.0–111.1, 95.0–106, 93.0–111.0%, respectively. The mechanism of the reaction between CF and DNA is also discussed.