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Cui H.,Yanshan University | Cui H.,Hebei Province Key Laboratory of Applied Chemistry | Wang L.,University of South Australia | Yu Y.,Flinders University
Journal of Chemistry | Year: 2015

A marine bacterium SD11, which was isolated from sea muds (Geziwo Qinhuangdao Sea area, China), was used to produce thermostable alkaline serine nonmetal protease in the skim milk agar plate medium with 10% NaCl. The optimal temperature about the manufacture of the extracellular protease was 60°C. The crude enzyme was stable at 20-50°C. The activity was retained to 60% and 45% after heating for 1 h at 60 and 70°C, respectively. The protease was highly active in a wide pH scope (8.0-10.0) and maximum protease activity exhibited at pH 10.0. The activity was restrained by phenylmethylsulfonyl fluoride (PMSF) but mildly increased (107%) in the presence of ethylenediaminetetraacetic acid (EDTA), indicating that the production contains serine-protease(s) and nonmetal protease(s). Moreover, the crude alkaline protease was active with the 5 mM Ca2+, Mn2+, Zn2+, Cu2+, Na+, and K+ that existed separately. In addition, the protease showed superduper stability when exposed to an anionic surfactant (5 mM SDS), an oxidizing agent (1% H2O2), and several organic solvents (methanol, isopropanol, and acetone). These results suggest that the marine bacterium SD11 is significant in the industry from the prospects of its ability to produce thermally stable alkaline protease. © 2015 Hongxia Cui et al. Source


Cui H.X.,Yanshan University | Cui H.X.,Hebei Province Key Laboratory of Applied Chemistry
Advanced Materials Research | Year: 2014

To explore the effect of crude polysaccharides of Dioscorea bulbifera L. (DBLP) on liver organs in mice bearing cervical cancer, the effects of DBLP on the liver weight in vivo, sections of liver were examined. Glutamate pyruvate transaminase(GPT) and Glutamic oxalo acetic Transaminase(GOT) activites of blood serum in tumor-bearing mice were detected by the colorimetric method. Superoxide dismutase(SOD) and Glutathione reductase(GR) of hepatic tissues were also determined by means of colorimetric method. Our results showed that the liver index, GPT and GOT activities of blood serum, SOD and GR activities of hepatic tissues of DBLP groups were almost the same as that of negative groups. however, the liver index, GPT and GOT activities of blood serum were decreased in DBLP groups compared to CTX groups. And the SOD and GR activities of hepatic tissues of DBLP groups were higher than that of CTX groups. These results demonstrated that DBLP had no effect on liver organs in mice bearing cervical cancer. These data would be a foundation for the appication of DBLP in antitumor, which indicated that DBLP would be a potential antitumor drug. And the further studies, such as antioxidant, should be developed. © (2014) Trans Tech Publications, Switzerland. Source


Cui H.,Yanshan University | Cui H.,Hebei Province Key Laboratory of Applied Chemistry | Yang M.,Yanshan University | Wang L.,University of South Australia | Xian C.J.,University of South Australia
PLoS ONE | Year: 2015

While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth) was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production. © 2015 Cui et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source


Ma Z.,Yanshan University | Ma Z.,State Key Laboratory of Metastable Materials Science and Technology | Ma Z.,Hebei Province Key Laboratory of Applied Chemistry | Shao G.,Yanshan University | And 11 more authors.
Ionics | Year: 2013

To improve the performance of LiFePO4, LiFe1-xMoxPO4/C (x = 0, 0.005, 0.010, 0.015, 0.020, 0.025) cathode materials were synthesized via two-step ball milling solid-state reaction. The prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectra, and galvanostatic charge-discharge test. It is apparent from XRD analysis that Mo doping enlarges the interplanar distance of crystal plane parallel to [010] direction in LiFePO4. In other words, it widens one-dimensional diffusion channels of Li+ along the [010] direction. The results of electrochemical test indicate that the LiFe0.99Mo0.01PO4/C composite exhibits a discharge capacity of 144.8 mAh g-1 at 1 C rate, a decreased charge transfer resistance of 162.4 Ω and better reversibility of electrode reactions. The present synthesis route is promising and practical for the preparation of LiFePO4 materials. © 2012 Springer-Verlag. Source


Du J.,State Key Laboratory of Metastable Materials Science and Technology | Du J.,Hebei Province Key Laboratory of Applied Chemistry | Du J.,Yanshan University | Shao G.,State Key Laboratory of Metastable Materials Science and Technology | And 14 more authors.
Materials Letters | Year: 2012

MnO 2 electrode material is successfully synthesized by electrodeposition under supergravity field from manganese acetate solution. The structure of the samples is characterized by X-ray diffraction. The results show that the product is γ-MnO 2. Galvanostatic charge/discharge measurements are applied to investigate electrochemical performances of the MnO 2 electrodes material prepared under different supergravity fields. MnO 2 synthesized under rotational speed 3000 rpm exhibits the highest specific surface area and discharge capacitance, the values of which are 68.6% and 19.3% higher than that under normal gravity fields, respectively. It is found that supergravity field can improve the electrochemical performance of MnO 2 material. © 2012 Elsevier B.V. All rights reserved. Source

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