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( Dong Ming Wang ),( Hong Shan Yu ),( Jian Guo Song ),( Yu Feng Xu ),( Chun Ying Liu ),( Feng Xie Jin ) 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.10
Herein, a novel ginsenosidase, named ginsenosidase type IV, hydrolyzing 6-O-multi-glycosides of protopanaxatrioltype ginsenosides (PPT), such as Re, R1, Rf, and Rg2, was isolated from the Aspergillus sp. 39g strain, purified, and characterized. Ginsenosidase type IV was able to hydrolyze the 6-O-α-L-(1→2)-rhamnoside of Re and the 6-O-β-D- (1→2)-xyloside of R1 into ginsenoside Rg1. Subsequently, it could hydrolyze the 6-O-β-D-glucoside of Rg1 into F1. Similarly, it was able to hydrolyze the 6-O-α-L-(1→2)- rhamnoside of Rg2 and the 6-O-β-D-(1→2)-glucoside of Rf into Rh1, and then further hydrolyze Rh1 into its aglycone. However, ginsenosidase type IV could not hydrolyze the 3-O- or 20-O-glycosides of protopanaxadioltype ginsenosides (PPD), such as Rb1, Rb2, Rb3, Rc, and Rd. These exhibited properties are significantly different from those of glycosidases described in Enzyme Nomenclature by the NC-IUBMB. The optimal temperature and pH for ginsenosidase type IV were 40℃ and 6.0, respectively. The activity of ginsenosidase type IV was slightly improved by the Mg2+ ion, and inhibited by Cu2+ and Fe2+ ions. The molecular mass of the enzyme, based on SDS-PAGE, was noted as being approximately 56 kDa.
( Xue Feng Jin ),( Hong Shan Yu ),( Dong Ming Wang ),( Ting Qiang Liu ),( Chun Ying Liu ),( Dong Shan An ),( Wan Taek Im ),( Song Gun Kim ),( Feng Xie Jin ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.3
In this paper, the kinetics of a cloned special glucosidase, named ginsenosidase type III hydrolyzing 3-O-glucoside of multi-protopanaxadiol (PPD)-type ginsenosides, were investigated. The gene (bgpA) encoding this enzyme was cloned from a Terrabacter ginsenosidimutans strain and then expressed in E. coli cells. Ginsenosidase type III was able to hydrolyze 3-O-glucoside of multi-PPD-type ginsenosides. For instance, it was able to hydrolyze the 3- O-β-D-(1→2)-glucopyranosyl of Rb1 to gypenoside XVII, and then to further hydrolyze the 3-O-β-D-glucopyranosyl of gypenoside XVII to gypenoside LXXV. Similarly, the enzyme could hydrolyze the glucopyranosyls linked to the 3-O- position of Rb2, Rc, Rd, Rb3, and Rg3. With a larger enzyme reaction Km value, there was a slower enzyme reaction speed; and the larger the enzyme reaction Vmax value, the faster the enzyme reaction speed was. The Km values from small to large were 3.85 mM for Rc, 4.08 mM for Rb1, 8.85 mM for Rb3, 9.09 mM for Rb2, 9.70 mM for Rg3(S), 11.4 mM for Rd and 12.9 mM for F2; and Vmax value from large to small was 23.2 mM/h for Rc, 16.6 mM/h for Rb1, 14.6 mM/h for Rb3, 14.3 mM/h for Rb2, 1.81mM/h for Rg3(S), 1.40 mM/h for Rd, and 0.41 mM/h for F2. According to the Vmax and Km values of the ginsenosidase type III, the hydrolysis speed of these substrates by the enzyme was Rc>Rb1>Rb3>Rb2>Rg3(S)>Rd>F2 in order.
Ming Xie,Jin-Long Liang,Han-Dong Huang,Mai-Jian Wang,Tao Zhang,Xue-Feng Yang 대한암학회 2019 Cancer Research and Treatment Vol.51 No.4
Purpose Nonylphenol (NP) is an endocrine disruptor found in products such as cleaners, plastics, and detergents. It exerts actions similar to endogenous 17-estradiol (E2) and is reported to influence various cancers. However, its role in colon cancer remains elusive. Materials and Methods Colon cancer cell lines COLO 205 and SW480 were employed in our study. The cells were treated with NP or E2 followed by measurement of apoptosis and proliferation using flow cytometry and MTT assays, respectively. G protein–coupled estrogen receptor 30 (GPR30) expression was visualized using immunofluorescence and Western blot. To investigate the underlying mechanism, the expression levels of GPR30, p-protein kinase A (PKA), c-myc, cyclin D1, and ERK1/2 were analyzed using Western blot. Meanwhile, the GPR30 antagonist G15 was utilized to validate the role of GPR30 in colon cancer progression. Finally, the effect of a GPR30 inhibitor on tumor growth was determined in vivo using tumor xenograft mouse models. Results NP facilitated the proliferation of colon cancer cells and induced apoptosis failure in vitro. Western blot revealed increased GPR30 expression levels in response to NP treatment. Cyclin D1, p-PKA, c-myc, and proliferating cell nuclear antigen, proteins that regulate the cell cycle, were all upregulated by NP, and NP-mediated ERK1/2 activation and subsequent cell proliferation were abrogated by the GPR30 inhibitor G15. Moreover, colon cancer mice that received G15 administration demonstrated impaired tumor growth in vivo. Conclusion Low dose NP promotes the growth of colon tumors through GPR30-mediated activation of ERK1/2 signaling.
Feng Ming,Yu Zhang,Dong-qing Li 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.5
The aim of this paper is to increase the understanding of ice lens initiation and growth in freezing soil. A model describing the growth process of ice lenses in soils has been established. The model presented here, which considers a series of processes, including heat transfer, water migration, phase change, ice lens formation, soil deformation, is solved by the use of a transient finite element. The simulated results agree with the experimental data. Results show that: (1) Negative pore water pressure occurs in unfrozen areas, this result in the water transfers from the unfrozen zone to the frozen zone and substantial water was stored in the frozen zone which results in oscillation with in water content distributions. (2) Few segregation ice lenses appeared in the fast freezing section, several thin and discontinuous segregation ice lenses appeared in the transitional section, and thick ice lenses appeared in the third phase when the freezing front tended to be stable. (3) Both the consolidation process and the expansion process are in progress during the freezing process, due to the migration of unfrozen water. (4) The frost heave model is composed of two aspects: the coupled heat-mass transport and the growth of ice lens. Numerical modeling is able to represent the development of both the thermal field and ice segregation observed in the physical models.
Xiao-Feng Zhang,Peng Dong,Ying-Jie Zhang,Xi-Kun Yang,Shu-Biao Xia,Zhen-Hua Jin,Ming-Li Xu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.3
Multi-walled carbon nanotubes (MWCNTs) were modified by hydrogen fluoride (HF) in a simple method. With the help of fluorine, Pd nanoparticles (3.9 nm) synthesized by a one-step photochemical reduction were uniformly self-assembled on the active sites of functionalized MWCNTs and a new catalyst (Pd/HF-MWCNT) was obtained. UV–Vis absorption spectra, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used. The results demonstrated that –F groups were introduced onto the surface of MWCNTs and C–F chemical bonds were formed. In addition, the electronic structure of Pd was changed. Pd–F coordination bond maybe formed between F atom and Pd atom. Cyclic voltammetry and chronoamperometry tests indicated that electrocatalytic activity of Pd/HF-MWCNTs catalyst for methanol in alkaline medium was about 1.6 times higher than that of the commercial Pd/C (JM) catalyst at the same condition. This new functionalized method has the advantages of simple step and safe operation. It is very significant to improve the wide application of MWCNTs and the commercial development of direct methanol fuel cells (DMFCs).