江西全南小慕泥盆-石炭系孢子组合及其地层意义

据30属57种(包含9新种)小孢子的垂直分布特征,将江西全南小慕泥盆一石炭系的小孢子划分为3个组合(自下而上):1)Acanthotriletes denticulatus-Apiculireiusispora raris(DR)组合,2) Leiotriletes macrothlis-Grandispora xiamuensis(MX)组合,uispinosa(TT)组合,3)Apiculiretusisporatera-Lycospora cf. thuispinosa(TT)组合.这3个组合分别产于三门滩组、翻下组与荒塘组-刘家塘组.据孢子资料的分析与植物、腕足类、鱼类等化石的佐证,三门滩组与翻下组的时代均属晚泥盆世晚期(Famennian),荒塘组与刘家塘组属早石炭世早期(Tournaisian).本区泥盆系与石炭系的界线置于翻下组与荒塘组之间较适合.     

Rapid screening of monoamine oxidase B inhibitors in natural extracts by capillary electrophoresis after enzymatic reaction at capillary inlet

A facile capillary electrophoresis (CE) method was developed for the screening of monoamine oxidase B (MAO-B) inhibitors in natural extracts. In this method, the enzymatic reaction occurred at the capillary inlet during a predetermined waiting period, followed by the electrophoretic separation of the reaction compounds, and detected by their UV absorbance at 280 nm. Conditions for the separation of substrates, products and enzyme were optimized. The optimal buffer composition was 50 mM N-2-hydroxyethyl-piperazine-N′-2-ethane sulphonic acid (HEPES) solution containing 10 mM SDS (pH = 7.4). Under the optimal condition, the baseline separation of substrates, products and enzyme was achieved within 2 min. The present method was used to determine MAO-B kinetic constants, K_i, K_m and IC₅₀ based on quantitative of the substrate peak area compared with the reference electropherogram obtained from without the inhibitor. A validation study shows good reproducibility for both migration time (RSD = 1.8%) and peak area (RSD = 3.9%). Finally, the screening of 16 natural extracts was performed, and 2 natural extracts from Fructus crataegi and Radix polygoni multiflori were identified to be positive for MAO-B inhibition.