Isolation of high-purity peptide Val-Val-Tyr-Pro from Globin Peptide using MCI gel column combined with high-speed counter-current chromatography.

Peptides have gained increased interest over the past several decades because of their therapeutics. In this research, a strategy combining MCI gel column chromatography and high-speed countercurrent chromatography was developed for the separation of high-purity peptide Val-Val-Tyr-Pro from Globin Peptide. First, the fraction of Val-Val-Tyr-Pro mixtures with a purity of 15.8% was obtained by using MCI gel column with a mixture of ethanol/water (20:80, v/v/v). Then, the high-purity Val-Val-Tyr-Pro was separated by high-speed countercurrent chromatography with a aqueous two phase systems of ethanol/acetonitrile/iso-propyl alcohol/(NH4 )2 SO4 Saturated solution /H2 O (0.5:0.5:0.25:1.5:0.7,v/v). The ammonium sulfate from high-speed countercurrent chromatography fractions was removed from target compound by MCI gel column chromatography using ethanol/water in stepwise elution mode. A 78 mg of Val-Val-Tyr-Pro was successfully purified with the purities of 98.80% from 30 g crude Globin Peptide. The amino acid sequence of the Val-Val-Tyr-Pro was determined by electrospray ionization high resolution tandem mass spectrometry. The method presents a practical strategy for the large-scale separation of pure peptide Val-Val-Tyr-Pro from Globin Peptide, and provides a reference method for obtaining high-purity peptide from other polypeptide mixtures.

A simple gradient equilibrium method for better separation in countercurrent chromatography.

The stationary phase retention is one of the most important parameters in countercurrent chromatography. In this work, a simple gradient equilibrium method was developed to further improve the stationary phase retention based on the optimized condition in the traditional equilibrium model. Meanwhile, this novel gradient equilibrium method was used to separate three flavone model compounds and compared with the conventional isocratic equilibrium method to evaluate the separation efficiency. The results show that better resolution or shorter separation time could be achieved with gradient equilibrium compared to isocratic equilibrium. So this novel equilibrium method has enormous potential for obtaining a better separation or saving the separating time in the preparative separation of target compounds.

[Comparative analysis on industrial standardization degree of Chinese and Korean ginseng].

Panax ginseng is a well-known medicinal plant all over the world. It has high nutritional value and medicinal value. China and South Korea are the major countries in the world for ginseng cultivation, production and exportation. China's ginseng production accounts for more than half of the world, but the output value is less than that of Korea. The standardization process of ginseng industry plays an important role. This paper makes a detailed analysis of the Chinese and Korean ginseng national standards and the standardization process, and makes a detailed comparative analysis of the categories, standard contents, index selection, age, implementation and promotion status of the Chinese and Korean ginseng standards. The development disadvantages of ginseng industry standardization were displayed. And we give our advises on the standard revision, implementation of China's ginseng industry standardization, hoping to enhance the competitiveness of China's ginseng industry.

A Rhodamine-based Dual Chemosensor for the Simultaneous Detection of Fe3+ and Cu2.

A Rhodamine-based dual chemosensor L1 for simultaneously detecting Fe3+ and Cu2+ was designed and synthesized. The spectroscopic properties of L1 were analyzed, and its recognition mechanism was speculated. We found that the addition of Fe3+ induced a great fluorescence enhancement, while Cu2+ induced a strong UV-Vis absorption enhancement. The results revealed that L1 was highly selective for recognizing Fe3+ and Cu2+ in UV-Vis spectroscopy in CH3OH-H2O (1/1, v/v, pH 7.2) with the interference of other metal ions. A good linear relationship between the fluorescence intensities of L1 and the concentration of Fe3+, as well as the UV-Vis absorption intensities of L1 and the concentration of Cu2+ was observed, respectively. The detection limit was 9.2 × 10-8 M (5.5 µg/L) for Fe3+ and 3.8 × 10-8 M (2.4 µg/L) for Cu2+, respectively. The detection capacity for targeted metal ions of Fe3+ and Cu2+ were studied, which are less than 5 min. Job's plot method for L1 with Fe3+ and ESI-MS for L1 with Cu2+ indicated a 1:1 stoichiometry in the complex. The results may provide an effective strategy for the design of new dual chemosensors for the rapid detection of targeted metal ions.

[Physical and chemical properties of throughfall in main forest types of secondary forest ecosystem in montane regions of eastern Liaoning Province, China].

From July to September 2008, a measurement was made on the physical and chemical properties of bulk precipitation and throughfall in five main forest types, i.e., larch plantation (LP), Fraxinus rhynchophylla stand (FR), mixed forest stand (MF), Korean pine plantation (KP), and Mongolian oak stand (MO), of secondary forest ecosystem in montane regions of eastern Liaoning Province, China. Comparing with bulk precipitation, the throughfall in the five forest types was significantly acidified (P < 0.05), and the acidification degree was in the order of KP > LP > MF > MO > FR. The conductivity and total dissolved solids of the throughfall increased significantly (P < 0.05), and were in the sequence of MO > FR > LP > MF > KP. The dissolved oxygen concentration of the throughfall lowered significantly (P < 0.05), with the rank of KP > MF > FR > MO > LP, while the Cl- concentration increased significantly, ranked as LP > MO > MF > FR > KP. The NO3-concentrations of the throughfall in FR, MO and MF were higher, while those in LP and KP were lower than that of the bulk precipitation.