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Zhang M.,Beijing Technology and Business University | Zhang M.,Beijing Higher Institution Engineering | Fang B.,Academy of State Administration of Grain | Chen L.,COFCO
Chemical Engineering Transactions | Year: 2015

Bovine lactoferrin (LF) was used to prepare complexes with oleic acid (OA) and linoleic acid (LnA), the antitumor activity of the lactoferrin-oleic acid complex (LF-OA) and lactoferrin-linoleic acid complex (LF-LnA) was measured on liver cancer, colon cancer and breast cancer cells using the methylene blue method. The structure changes of LF induced by binding of OA and LnA, including hydrophobic amino acids, hydrophobic regions, tertiary structure, secondary structure, was studied by intrinsic fluorescence, ANS-binding intrinsic fluorescence and circular dichroism spectrum, respectively. Both of LF-OA and LF-LnA exhibited profound anti-tumor activity on the three types of tumor cells. A significant red-shift of LF occurred after binding of OA and LnA, respectively. Meanwhile, the ANS-binding spectra of LF exhibited a blue-shift with an increasing fluorescence intensity. It can be indicated from the fluorescence spectra results that binding of OA and LA lead to the exposure of hydrophobic amino acids and hydrophobic regions. Furthermore, circular dichroism spectra suggested a partial loss of the tertiary structure, a decrease in the content of a-helix and β-turn with the increase of β-sheet and random coil structure. Here in this study, we successfully prepared the two antitumor LF-OA and LF-LnA complexes, which exhibited a profound prospect of cancer therapy. Copyright © 2015, AIDIC Servizi S. r. l.,. Source


Zhang H.,China Agricultural University | Yu D.,China Agricultural University | Sun J.,China Agricultural University | Liu X.,China Agricultural University | And 4 more authors.
Nutrition Research Reviews | Year: 2014

Polyphenols are dietary constituents of plants associated with health-promoting effects. In the human diet, polyphenols are generally consumed in foods along with macronutrients. Because the health benefits of polyphenols are critically determined by their bioavailability, the effect of interactions between plant phenols and food macronutrients is a very important topic. In the present review, we summarise current knowledge, with a special focus on the in vitro and in vivo effects of food macronutrients on the bioavailability and bioactivity of polyphenols. The mechanisms of interactions between polyphenols and food macronutrients are also discussed. The evidence collected in the present review suggests that when plant phenols are consumed along with food macronutrients, the bioavailability and bioactivity of polyphenols can be significantly affected. The protein-polyphenol complexes can significantly change the plasma kinetics profile but do not affect the absorption of polyphenols. Carbohydrates can enhance the absorption and extend the time needed to reach a maximal plasma concentration of polyphenols, and fats can enhance the absorption and change the absorption kinetics of polyphenols. Moreover, as highlighted in the present review, not only a nutrient alone but also certain synergisms between food macronutrients have a significant effect on the bioavailability and biological activity of polyphenols. The review emphasises the need for formulations that optimise the bioavailability and in vivo activities of polyphenols. © 2014 The Authors. Source


Dong F.,Beijing University of Civil Engineering and Architecture | Dong J.,Beijing University of Civil Engineering and Architecture | Dong J.,Beijing Higher Institution Engineering | Sun W.Z.,Beijing University of Civil Engineering and Architecture
Applied Mechanics and Materials | Year: 2012

Based on the background of a subway construction project, deterioration characteristics of the existed subway tunnels under long-term train loads is studied by using the method of stiffness discount which could reflect fatigue damage of the structure. Firstly, dynamic response of the tunnel with initial defects caused by approaching construction under long-term train loads is analyzed according numerical simulation, and some results under different degrees of fatigue are obtained. Then, numerical results of acceleration responses at such different points as the upper vault, the side wall and the bottom of tunnels in two directions, are compared with each other while the train loads are applied at the left tunnel, especially under three different stiffness. Our investigation shows local structural damage in the position with initial cracks will be caused by a high cycle stress although there are fewer influences of stiffness changes on dynamic response of tunnels. © (2012) Trans Tech Publications, Switzerland. Source


Li X.,Beijing Technology and Business University | Li E.,Beijing Technology and Business University | Zhu Y.,Beijing Technology and Business University | Teng C.,Beijing Technology and Business University | And 4 more authors.
Carbohydrate Research | Year: 2012

The activity of the extracellular xylanase produced by Streptomyces rameus L2001 against different xylans and xylooligosaccharides (XOS) was investigated. The main products of hydrolysis of birchwood xylan and oat-spelt xylan by the S. rameus L2001 xylanase were xylobiose (X2) and xylotriose (X3), suggesting that this is an endo-acting xylanase. This was confirmed by analysis of XOS degradation products. The enzyme hardly hydrolyzed X2 and X3, but hydrolyzed xylotetraose (X4) and xylopentaose (X5) producing mainly X2 and X3 through transglycosylation. Depending on the substrate, different quantities of reducing sugars were produced by the xylanase: 150 mg/g from corncob, 105 mg/g from bean culms, and 133 mg/g from bagasse. With the bagasse substrate, the xylanase yielded 2.36, 2.76, 2.03, and 2.17 mg/mL of X2, X3, X4, and X5, respectively. The structure of xylobiose and xylotriose from the hydrolysis of corncob xylan was identified by MS and NMR. The production of XOS from various agricultural wastes has potential industrial applications. This is the first report of XOS production by S. rameus L2001. © 2012 Elsevier Ltd. All rights reserved. Source


Fang B.,China Agricultural University | Fang B.,Beijing Key Laboratory of Nutrition | Zhang M.,China Agricultural University | Zhang M.,Beijing Higher Institution Engineering | And 7 more authors.
Protein Journal | Year: 2012

The biological function of α-lactalbumin (α-LA) depends on its conformation. α-LA can adopt a stable intermediate state induced by heating or pH change. This intermediate state associates with oleic acid (OA) to form an anti-tumor complex. The effect of temperature on the formation the complex has been studied, whereas the effect of pH on complex formation remains unresolved. The effect of pH on tryptophan residues, hydrophobic clusters and secondary structure of Ca2+-depleted bovine α-LA (BLA) was studied by fluorescence spectroscopy and circular dichroism. BLA was found to adopt a more flexible conformation between pH 7.0 and 9.0 with buried hydrophobic clusters. The binding ability of α-LA towards OA and the anti-tumor activity of the corresponding complex were also studied. BLA was found to bind more OA over the pH range of 7.0-9.0 and the corresponding complexes showed a higher anti-tumor activity than those complexes formed under acidic conditions. Our study indicates that alkaline pH aided the formation of the complex as well as its anti-tumor activity. We also propose a possible characteristic structure that facilitates binding of OA. © 2012 Springer Science+Business Media, LLC. Source

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