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Rui B.,Anhui Agricultural University | Yi Y.,Guizhou Normal University | Shen T.,Guizhou Normal University | Zheng M.,Guizhou Academy of Testing and Analysis | And 9 more authors.
PLoS ONE | Year: 2015

NADPH regeneration capacity is attracting growing research attention due to its important role in resisting oxidative stress. Besides, NADPH availability has been regarded as a limiting factor in production of industrially valuable compounds. The central carbon metabolism carries the carbon skeleton flux supporting the operation of NADPH-regenerating enzyme and offers flexibility in coping with NADPH demand for varied intracellular environment. To acquire an insightful understanding of its NADPH regeneration capacity, the elementary mode method was employed to compute all elementary flux modes (EFMs) of a network representative of central carbon metabolism. Based on the metabolic flux distributions of these modes, a cluster analysis of EFMs with high NADPH regeneration rate was conducted using the self-organizing map clustering algorithm. The clustering results were used to study the relationship between the flux of total NADPH regeneration and the flux in each NADPH producing enzyme. The results identified several reaction combinations supporting high NADPH regeneration, which are proven to be feasible in cells via thermodynamic analysis and coincident with a great deal of previous experimental report. Meanwhile, the reaction combinations showed some common characteristics: There were one or two decarboxylation oxidation reactions in the combinations that produced NADPH and the combination constitution included certain gluconeogenesis pathways. These findings suggested cyclization pathways as a powerful way for NADPH regeneration capacity of bacterial central carbon metabolism. Copyright © 2015 Rui et al.


Li R.-H.,Guizhou Academy of Testing and Analysis | Li R.-H.,Guizhou Huake Aluminum Engineering Research Co. | Zeng P.,Guizhou Academy of Testing and Analysis | Zhang J.-D.,Guizhou Academy of Testing and Analysis
Zhuzao/Foundry | Year: 2013

GB/T 29434-2012 has been issued on December 31, 2012, and will be implemented on September 1, 2013. This standard has been published by the China Standard Publishing House. It is a voluntary National Standard of the People's Republic of China for the first time drafting. Aluminum alloy for high strength and toughness castings with heat resisting is a new material that has excellent casting performance and mechanical properties but is unfamiliar to the users. In this paper, the GB/T 29434-2012 was interpreted in detail so that users and readers could further understand the main product features.


Zhang Q.,Beijing Institute of Technology | Zhang Q.,Guizhou Academy of Testing and Analysis | Lin C.,Guizhou Academy of science | Duan W.,Shandong Academy of Sciences | And 2 more authors.
Molecules | Year: 2013

pH-Zone refining counter-current chromatography was successfully applied to the preparative isolation and purification of six alkaloids from the ethanol extracts of Uncaria macrophylla Wall. Because of the low content of alkaloids (about 0.2%, w/w) in U. macrophylla Wall, the target compounds were enriched by pH-zone refining counter-current chromatography using a two-phase solvent system composed of petroleum ether-ethyl acetate-isopropanol-water (2:6:3:9, v/v), adding 10 mM triethylamine in organic stationary phase and 5 mM hydrochloric acid in aqueous mobile phase. Then pH-zone refining counter-current chromatography using the other two-phase solvent system was used for final purification. Six target compounds were finally isolated and purified by following two-phase solvent system composed of methyl tert-butyl ether (MTBE)-acetonitrile-water (4:0.5:5, v/v), adding triethylamine (TEA) (10 mM) to the organic phase and HCl (5 mM) to aqueous mobile phase. The separation of 2.8 g enriched total alkaloids yielded 36 mg hirsutine, 48 mg hirsuteine, 82 mg uncarine C, 73 mg uncarine E, 163 mg rhynchophylline, and 149 mg corynoxeine, all with purities above 96% as verified by HPLC Their structures were identified by electrospray ionization-mass spectrometry (ESI-MS) and 1H-NMR spectroscopy. © 2013 by the authors; licensee MDPI, Basel, Switzerland.


Zhang Q.,Beijing Institute of Technology | Zhang Q.,Guizhou Academy of Testing and Analysis | Shu X.,Shandong Academy of Sciences | Jing F.,Shandong Academy of Sciences | And 3 more authors.
Molecules | Year: 2014

Two high-speed countercurrent chromatography (HSCCC) modes were compared by separation of major alkaloids from crude extract of Picrasma quassioides. The conventional HSCCC separation was performed with a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water (5:5:4.5:5.5, v/v/v/v) with 200 mg loading. pH-Zone-refining CCC was performed with two-phase solvent system composed of petroleum ether-ethyl acetate-n-butanol-water (3:2:7:9, v/v/v/v) where triethylamine (10 mM) was added to the upper organic stationary phase and hydrochloric acid (5 mM) was added to the lower aqueous phase with 2 g loading. From 2 g of crude extract, 87 mg of 5-methoxycanthin-6-one (a), 38 mg of 1-methoxy-β-carboline (b), 134 mg of 1-ethyl-4,8-dimethoxy-β- carboline (c), 74 mg of 1-ethoxycarbonyl-β-carboline (d), 56 mg of 1-vinyl-4,8-dimethoxy-β-carboline (e) and 26 mg of 1-vinyl-4-dimethoxy- β- carboline (f) were obtained with purities of over 97.0%. The results indicated that pH-zone-refining CCC is an excellent separations tool at the multigram level.


Chen K.,Beijing University of Chemical Technology | Chen K.,Guizhou Academy of Testing and Analysis | Tan H.,Guizhou Academy of Testing and Analysis | Tan H.,Beijing University of Chemical Technology | And 2 more authors.
Applied Mechanics and Materials | Year: 2014

Food safety has been in the spotlight of the global attention. In 2013, China's food safety supervision policy was undertaken a major reform. China Food and Drug Administration (CFDA) takes over the responsibility of food safety management, which in the past was conducted by different government sectors. Under this new management system, how to carry out the practical work has become a new issue. This paper introduces an innovative food safety management mode adopted by Guizhou province. On the basis of latest information technology, food production enterprises, government, testing organizations and consumers are integrated into a unified food safety information service cloud platform. The core technology of cloud platform is composed of food safety knowledge system, testing management system, food safety information publicity system as well as mobile application. The food factory inspection data, government inspection data, testing organization's testing data and consumer's purchasing information are integrated into food safety and nutrient test big data. Utilizing the data to explore the information that is needed by all the parties, this paper tries to provide a solution to the risk exchange problem faced by China's food safety issue. At the same time, food safety problem can be solved through the contribution of different stakeholders. © (2014) Trans Tech Publications, Switzerland.

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