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Molecular and Biochemical Characterization of a Novel Intracellular Low-Temperature-Active Xylanase
( Jun Pei Zhou,),( Yan Yan Dong ),( Xiang Hua Tang ),( Jun Jun Li ),( Bo Xu ),( Qian Wu ),( Ya Jie Gao ),( Lu Pan ),( Zun Xi Huang ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.4
A 990 bp full-length gene (xynAHJ2) encoding a 329- residue polypeptide (XynAHJ2) with a calculated mass of 38.4 kDa was cloned from Bacillus sp. HJ2 harbored in a saline soil. XynAHJ2 showed no signal peptide, distinct amino acid stretches of glycoside hydrolase (GH) family 10 intracellular endoxylanases, and the highest amino acid sequence identity of 65.3% with the identified GH 10 intracellular mesophilic endoxylanase iM-KRICT PX1-Ps from Paenibacillus sp. HPL-001 (ACJ06666). The recombinant enzyme (rXynAHJ2) was expressed in Escherichia coli and displayed the typical characteristics of low-temperatureactive enzyme (exhibiting optimum activity at 35 o C, 62% at 20 o C, and 38% at 10 o C; thermolability at ≥45 o C). Compared with the reported GH 10 low-temperature-active endoxylanases, which are all extracellular, rXynAHJ2 showed low amino acid sequence identities (<45%), low homology (different phylogenetic cluster), and difference of structure (decreased amount of total accessible surface area and exposed nonpolar accessible surface area). Compared with the reported GH 10 intracellular endoxylanases, which are all mesophilic and thermophilic, rXynAHJ2 has decreased numbers of arginine residues and salt bridges, and showed resistance to Ni 2+ , Ca 2+ , or EDTA at 10 mM final concentration. The above mechanism of structural adaptation for low-temperature activity of intracellular endoxylanase rXynAHJ2 is different from that of GH 10 extracellular low-temperature-active endoxylanases. This is the first report of the molecular and biochemical characterizations of a novel intracellular low-temperatureactive xylanase.
( Jun Pei Zhou ),( Qian Wu ),( Rui Zhang ),( Yu Ying Yang ),( Xiang Hua Tang ),( Jun Jun Li ),( Jun Mei Ding ),( Yan Yan Dong ),( Zun Xi Huang ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.6
This paper reports the production and characterization of crude xylanase from the newly isolated Humicola sp. Ly01. The highest (41.8 U/ml) production of the crude xylanase was obtained under the optimized conditions (w/v): 0.5% wheat bran, 0.2% KH2PO4, and 0.5% peptone; initial pH 7.0; incubation time 72 h; 30℃; and 150 rpm. A considerable amount of the crude xylanase was induced using hulless barley bran or soybean meal as the carbon source, but a small amount of the enzyme was produced when supplementary urea was used as the nitrogen source to wheat bran. The crude xylanase showed apparent optimal cellulase-free xylanase activity at 60℃ and pH 6.0, more than 71.8% of the maximum xylanase activity in 3.0-30.0% (v/v) ethanol and more than 82.3% of the initial xylanase activity after incubation in 3.0-30.0% (v/v) ethanol at 30℃ for 2 h. The crude xylanase was moderately resistant to both acid and neutral protease digestion, and released 7.9 and 10.9 μmol/ml reducing sugar from xylan in the simulated gastric and intestinal fluids, respectively. The xylooligosaccharides were the main products of the hydrolysis of xylan by the crude xylanase. These properties suggested the potential of the crude enzyme for being applied in the animal feed industry, xylooligosaccharides production, and high-alcohol conditions such as ethanol production and brewing.
Xiang-Feng Wu,Yi-Jin Wang,Zuo-Lin Cao,Yan-Mei Feng,Hui Li,Chen-Xu Zhang,Jun-Zhang Su,Jia-Rui Zhang,Yi-Wei Wang,Kai-Yuan Wang,Guo-Wen Sun 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.7
The novel AgCl/Ag2SO3 hybrids as an efficient photocatalyst had been fabricated by an in situ synthetic method. The correlations between the structure and the photocatalytic properties of the as-fabricated hybrids were analyzed. Experimental results exhibited that with increasing the amount of Ag2SO3, the degradation rate of the as-obtained samples was firstly increased and then decreased under the visible light irradiation. When the mass ratio of AgCl to Ag2SO3 was 1:2, in 30?min, it displayed the highest degradation rate of 99.2% for rhodamine-B, which was obviously higher than 46.1, 60.5, and 14.6% of pure AgCl, Ag2SO3, and TiO2 (P25), respectively. Similar results could be found in degradation of methyl orange. It had the maximum of 97.4% in 90?min, which was higher than 55.2, 48.7, and 12.7% of pure AgCl, Ag2SO3, and P25, respectively. Moreover, the as-prepared hybrids possessed the enhanced separation and transfer of photo-generated electron?hole pairs compared to the pure samples. In addition, the holes and superoxide radicals played the dominant role and the hydroxyl radicals played the secondary role during the process of photocatalytic degradation.
Yan, Jun-Hong,Pan, Lei,Zhang, Xiao-Min,Sun, Cui-Xiang,Cui, Guang-He Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8
Background: It is controversial whether Tai Chi (TC) benefits breast cancer survivors (BCS) on quality of life (QoL). We therefore undertook a meta-analysis to assess this question. Materials and Methods: A computerized search through electronic databases was performed to identify relevant randomized controlled trials (RCTs). The primary outcome was QoL, while secondary outcomes included body mass index (BMI), bone mineral density (BMD), and muscle strength. Results: Five RCTs involving 407 patients were included in the meta-analysis. The pooled standardized mean differences were 0.10 (95% confidence interval (CI): -0.35-0.54) for physical well-being, 0.03 (95%CI: -0.18-0.25) for social/family well-being, 0.24 (95%CI: 0.02-0.45) for emotional well-being, 0.23 (95%CI: -0.03-0.49) for functional well-being, and 0.09 (95%CI: -0.19-0.36) for additional concerns. TC failed to improve BMI, BMD, and muscle strength. Conclusions: There is currently lack of sufficient evidence to support TC improving QoL and other important clinical endpoints.
( Xiang Cheng ),( Jun Hua Li ),( Jie Deng ),( Zhen Zhen Li ),( Shu Yan Meng ),( Hua Yan Wang ) 생화학분자생물학회 (구 한국생화학분자생물학회) 2012 BMB Reports Vol.45 No.1
The present study aimed to investigate the function of translationally controlled tumor protein (TCTP) in the regulation of Oct4 in mouse embryonic carcinoma P19 cells and mouse J1 embryonic stem (ES) cells. The mRNA level of endogenous TCTP in somatic cells was 2-4 folds higher than that in pluripotent P19 and J1 ES cells. Overexpression of TCTP in mouse pluripotent cells not only reduced the level of Oct4 transcription, but also decreased the pluripotency of stem cells. The N-terminal end of TCTP (amino acids 1-60) played an important role in suppressing the Oct4 promoter. Moreover, overexpression of TCTP in P19 cells suppressed the Oct4 promoter activity in a dose- and a time-dependent manner. In addition, knockdown of TCTP by small interfering RNA increased the expression of Oct4. Our study indicates that TCTP downregulates the Oct4 expression by binding the Sf1 site of Oct4 promoter in mouse pluripotent cells. [BMB reports 2012; 45(1): 20-25]
Differential Spatial Modulation With Gray Coded Antenna Activation Order
Jun Li,Miaowen Wen,Xiang Cheng,Yier Yan,Sangseob Song,Moon Ho Lee IEEE 2016 IEEE communications letters Vol.20 No.6
<P>In this letter, we propose a gray code order of antenna index permutations for differential spatial modulation (DSM). To facilitate the implementation, the well-known Trotter-Johnson ranking and unranking algorithms are adopted, which result in similar computational complexity to the existing DSM that uses the lexicographic order. The signal-to-noise ratio gain achieved by the proposed gray code order over the lexicographic order is also analyzed and verified via simulations. Based on the gray coding framework, we further propose a diversity-enhancing scheme named intersected gray (I-gray) code order, where the permutations of active antenna indices are selected directly from the odd (or even) positions of the full permutations in the gray code order. From analysis and simulations, it is shown that the I-gray code order can harvest an additional transmit diversity order with respect to the gray code order.</P>
High Temperature Deformation Behavior and Processing Map for a Nickel-Titanium Shape Memory Alloy
Xiang-Qian Yin,이상원,Yan-Feng Li,박찬희,Xu-Jun Mi,염종택 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.5
The hot deformation behavior of 49.2Ti-50.8Ni shape memory alloy was studied using hot compressive deformationtesting in the temperature range of 1023-1323 K and at strain rates of 0.01-10 s-1. The work-hardening rate wasinduced to analyze the stress-strain curves, and the critical stress σc and the dynamic recovery saturation stress σsatwere measured which can be specified approximately by the expressions: σsat-1.12σp and σc-0.86σp. An Arrheniusmodel was calculated to describe the relationship between peak stress and the Z parameter. The relationshipbetween deformation activation energy, the deformation conditions and the effect of Ni component in a binaryTiNi alloy on the activation energy were discussed in this work. With the help of electron backscattering diffraction,a connected mode dynamic recrystallization microstructure was confirmed in peak efficiency regimes(850 °C & 0.01 s-1 and 1050 °C & 10 s-1) of the processing map.
( Xiang E Long ),( Zhao Hui Gong ),( Lin Pan ),( Zhi Wei Zhong ),( Yan Ping Le ),( Qiong Liu ),( Jun Ming Guo ),( Jiu Chang Zhong ) 한국생화학분자생물학회 (구 한국생화학회) 2010 BMB Reports Vol.43 No.4
Cyclin-dependent kinase 2 (CDK2) is a member of serine/threonine protein kinases, which initiates the principal transitions of the eukaryotic cell cycle and is a promising target for cancer therapy. The present study was designed to inhibit cdk2 gene expression to induce cell cycle arrest and cell proliferation suppression. Here, we constructed a series of RNA interference (RNAi) plasmids which can successfully express small interference RNA (siRNA) in the transfected human cells. The results showed that the RNAi plasmids containing the coding sequences for siRNAs down-regulated the cdk2 gene expression in human cancer cells at the mRNA and the protein levels. Furthermore, we found that the cell cycle was arrested at G0G1 phases and the cell proliferation was inhibited by different siRNAs. These results demonstrate that suppression of CDK2 activity by RNAi may be an effective strategy for gene therapy in human cancers. [BMB reports 2010; 43(4): 291-296]
Jun Woo Lee,Uy Dong Sohn,Chung-Hyo Kim,Yi-Yi Wang,Xiang Mei Yan 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.1
Lysophosphatidic acid (LPA) is a lipid mediator that is involved in many biological responses, such as, in the stimulation/inhibition of proliferation, in cell migration, antiapoptosis, tumor cell invasion, platelet aggregation, vascular remodeling, and neurotransmitter release. In addition, LPA indirectly enhances the contractility of smooth muscle. Furthermore, electric field stimulation (EFS) causes contractions of isolated cat esophageal smooth muscle and relaxations of isolated cat lower esophageal sphincter (LES). To test whether or not LPA enhances postsynaptically-mediated contraction in cat esophageal smooth muscle and LES, both types of muscle strips were stimulated with muscarinic agonists. However, no significant effects were observed, and therefore, to investigate whether LPA is involved in presynaptic signal transduction, cat esophageal smooth muscle and LES were pretreated with LPA and stimulated using EFS. LPA had no effect on EFS-induced contraction in esophageal smooth muscle but the EFSinduced LES relaxation was dose-dependently inhibited by LPA. To identify the LPA receptor subtype that inhibits EFS-induced LES relaxation, we used the specific LPA1/LPA3 antagonist Ki16425 and the LPA3 agonist OMPT. Ki16425 significantly blocked the inhibitory effect of LPA on EFS-induced relaxation, but OMPT did not enhance the effect of LPA. These results suggest that LPA inhibits EFS-induced relaxation in LES via LPA1 receptor-mediated signaling. It is well known that EFS-induced LES relaxation is related to the release of neurotransmitters, such as, nitric oxide, vasoactive intestinal polypeptide, and calcitonin gene-related peptide. We then investigated whether LPA selectively blocks NO-mediated signaling. Sodium nitroprussideinduced LES relaxation was found to be inhibited in the same manner as EFS-induced LES relaxation by LPA. This result suggests that LPA partially blocks NO uptake by presynaptic pathways, and thus, inhibits LES relaxation.