Li Y.-C.,Hainan University
Process Biochemistry | Year: 2014
To study the combination effects of glycometabolic regulator NaF and elicitor methyl jasmonate (MJ) on cephalotaxine production in Cephalotaxus mannii suspension cultures, NaF of 10 mg/L, MJ of 100 μmol/L or both of them (NaF + MJ for short below) were added to the shake-flask cultures of C. mannii cell. It was found that NaF increased the activity of glucose 6-phosphate dehydrogenase (G6PDH), but had no significant effects on phenylalanine ammonium-lyase (PAL) activity and phenols formation. In contrast, MJ could activate PAL activity and led to phenols accumulation, but had no significant effects on G6PDH activity. To explore the effects of NaF and MJ on cephalotaxine biosynthesis, harringtonine and homoharringtonine, the two cephalotaxines, were analyzed in this work. The results obtained indicated that NaF + MJ treatment showed the strongest promotion of production in all tests. Harringtonine yield in NaF + MJ treated cells (7.245 mg/L) was 4.8-fold higher than that in control cells (1.506 mg/L), 1.7-fold that in NaF-treated cells (4.12 mg/L) and 1.6-fold that in MJ-treated cells (4.458 mg/L), respectively. No homoharringtonine was found besides in NaF + MJ treated cells (0.491 mg/L). With respect of the product release rates, they were 0%, 78%, 24% and 62% in control, NaF, MJ and NaF + MJ treatment, respectively. These results suggest that the combination of NaF and MJ had contributed to the synthesis and secretion of cephalotaxine in C. mannii cells. © 2014 Elsevier Ltd. All rights reserved.
Ou Y.-G.,Hainan University
International Journal of Computer Mathematics | Year: 2014
This paper presents a new hybrid algorithm for unconstrained optimization problems, which combines the idea of the IMPBOT algorithm with the nonmonotone line search technique. A feature of the proposed method is that at each iteration, a system of linear equations is solved only once to obtain a trial step, via a modified limited-memory BFGS two loop recursion that requires only matrix–vector products, thus reducing the computations and storage. Furthermore, when the trial step is not accepted, the proposed method performs a line search along it using a modified nonmonotone scheme, thus a larger stepsize can be yielded in each line search procedure. Under some reasonable assumptions, the convergence properties of the proposed algorithm are analysed. Numerical results are also reported to show the efficiency of this proposed method. © 2014, © 2014 Taylor & Francis.
Xu J.,Hainan University
RSC Advances | Year: 2015
This review summarizes new findings concerning the sources and characteristics of various natural products that can be extracted from mangrove-associated microbes over the past three years (January 2011-December 2013). The natural products are discussed with a focus on bioactivity, highlighting the unique chemical diversity of these metabolic products. © The Royal Society of Chemistry 2015.
Wen W.,Hainan University |
Wu J.-M.,Zhejiang University
RSC Advances | Year: 2014
Solution combustion synthesis (SCS) is a worldwide adopted technique to synthesize nanomaterials, especially for oxides, because of its simplicity, energy and time-effectiveness, and low cost. The general difficulty encountered in SCS is the controllability over phases and morphologies of the products, which arises from the inherent rapid and uncontrollable combustion procedure. In this regard, the present work is devoted to review the recent progress on phase- and morphology-controlled SCS in detail. Besides the various metal oxides, SCS is now applicable to fabricate nanomaterials of metal phosphates, metal silicates, metal borates, metal sulfides, metals, and even alloys, through careful selection of solution compositions. Oxides with regular morphologies of flowers, belts, triangles, tubes, wires, and rods can be synthesized by SCS, in the presence of certain templates, or through a self-assembly procedure. The recent progress made on the synthesis of porous materials via SCS is summarized. SCS is also capable of growing metal oxide thin films at low temperatures, enabling the fabrication of low-cost and high-performance electronics on flexible plastic substrates. This journal is © The Royal Society of Chemistry.
Bo Ning Z.J.,Hainan University
Journal of Networks | Year: 2013
Existing methods and technologies for Web services discovery mainly consist of two models: service matching based on grammar and based on semantics. With keywords service matching method, we introduce text information retrieval technology with vectors and concept lattice theory. Then a web service discovery algorithm using eigenvectors is put forward. It orders the Web services by correlation among the services in Web service subset. The services which have bigger correlation will get anterior places. According to this algorithm a Web service discovery system based on eigenvectors is designed. We give description to key modules of the system. At last the improved algorithm is compared to methods based on full-text retrieval and pure similarity retrieval. The results show it has better performance in accuracy and response. © 2013 ACADEMY PUBLISHER.