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	1. Identification, characterization and gene cloning of a phytase with potential industrial interest
	Ming-Lv Sun,Bo Zhou,Jian Sun,Dong-Min Zhao,Xiao-Yun Wang
	Biology 12 April 2007
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	Abstract:A high phytase-producing strain of Aspergillus niger N-3 was identified by screening 94 microbial strains. The phytase displayed physicochemical characteristics of potential industrial interest with independent intellectual property. The enzyme activity in fermented broth achieved a maximum of 495 U/mL. The enzyme was purified by a combination of ammonium sulfate fractionation and gel filtration chromatography. The molecular weight of the enzyme as determined by SDS-PAGE was 60-80 kDa, with maximum activity at about 55 C (after incubation at 10 min). Dual optima pH (pH 2.0 and pH 5.5) was gained. Activity at pH 2.0, which is more suitable to the circumstance of monogastric animals’ stomach was about 30% higher than that at pH 5.5. The phytase retained about 45% of its enzymatic activity under heat treatment at 90 C for 5 min. It showed a greater affinity for sodium phytate (Km = 132.3 μM) than for pNPP (Km = 2.23 mM). The phyA gene was isolated and sequenced. The coding region without the introns and putative signal sequence was comprised of 1347 nucleotides. It encoded a polypeptide of 448 amino acids， exhibiting high amino acid sequence homologies (94.87%) with the typical phytase Aspergillus niger NRRL 3135.
	TO cite this article:Ming-Lv Sun,Bo Zhou,Jian Sun, et al. Identification, characterization and gene cloning of a phytase with potential industrial interest[OL].[12 April 2007] http://en.paper.edu.cn/en_releasepaper/content/12158


	2. Screening, Cloning and Overexpression of Aspergillus niger phytase (phyA) in Pichia pastoris with favorable characteristics
	Dong-Min Zhao,Min Wang,Xi-Jun Mu,Ming-Lv Sun,Xiao-Yun Wang
	Biology 09 April 2007
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	Abstract:An Aspergillus niger spp. which produces extracellular phytase was isolated. The phyA gene was cloned and sequenced. The results show that the coding region comprises 1347 bp and the homology of nucleotide sequence and amino acid sequence with A. niger NRRL 3135 were about 96% and 93.8%, respectively. The coding sequence phyA fragment was cloned into Pichia secretive expression vector pPICZA and then transformed into chromosome of Pichia pastoris GS115 strain by electroporation. After stepwise screenings by antibiotics zeocin, yeast PCR and induction by methanol, one transformant showed high expression. The activity of fermented broth was 30000-fold of original Aspergillus niger spp. phytase (0.008 U•ml-1) and the specific activity was 503 U•mg-1 of protein. The Km value was 0.196 mmoll-1 for sodium phytate and 18.16 mmoll-1 for pNPP. It showed activity at pH range values of 2-6 with the optimum at 5.5. Studies on thermostability showed that the recombinant phytase remained 70% activity after exposure to 90℃ for 5 min and 65% for 30 min. Fluorescence analyses show that when the enzyme was treated at increasing temperatures, a little fluorescence red-shift was observed (4 nm) with an increase in emission intensity, which indicates that the conformation of the enzyme was very stable during the heating process.
	TO cite this article:Dong-Min Zhao,Min Wang,Xi-Jun Mu, et al. Screening, Cloning and Overexpression of Aspergillus niger phytase (phyA) in Pichia pastoris with favorable characteristics[OL].[ 9 April 2007] http://en.paper.edu.cn/en_releasepaper/content/12053


	3. Optimization of an enzyme production medium and bioconversion conditions for L (+)-tartaric acid production by Corynebaterium sp. in fed-batch culture
	Wenpeng Li,Jinlun Xie
	Biology 24 February 2007
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	Abstract:The medium for production of cis-epoxysuccinate hydrolase from Corynebaterium sp. YNUCC0211 and bioconversion conditions for L (+)-tartrate production were optimized by means of statistical methods respectively. Results revealed that the yields of L (+)-tartrate were improved by feeding fresh synthesized cis-expoxysuccinate solution with 12.0 of pH or with 3% of hydrogen peroxide to the optimum medium after being inoculated for 32-48 hours. The optimum medium contains (g/litre): glucose 15, cornsteep liquor 3.0, yeast extraction 0.3, K2HPO4.3H2O 3.5, dipotassium cis-epoxysuccinate 7.0, NH4NO3 4.0, (NH4)2 SO4 1.0, MgSO4.7H2O 1.0, FeSO4.7H2O 0.02, pH 7.0 - 7.2.
	TO cite this article:Wenpeng Li,Jinlun Xie. Optimization of an enzyme production medium and bioconversion conditions for L (+)-tartaric acid production by Corynebaterium sp. in fed-batch culture[OL].[24 February 2007] http://en.paper.edu.cn/en_releasepaper/content/11195


	4. Functional characterization of a Root-knot nematode resistance gene Mi from tomato (Lycopersicon esculentum L.)
	Chen Rugang,Zhang Liying,Zhang Junhong,Zhang Wei,Wang Xue,Ouyang Bo,Li Hanxia,Ye Zhibiao
	Biology 29 March 2006
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	Abstract:Root-knot nematodes (Meloidogyne spp.) cause major economic damage of numerous crop species around the world. Plant resistance is the most important attribute that is able to suppress invasion by the root-knot nematodes. In present study, a candidate root-knot nematode resistance gene Mi was isolated from the resistant tomato line RN-1. Expression profiling analysis revealed that this gene expressed specifically in roots, stems and leaves, but not in flowers or fruits. To verify the real function of this candidate gene, both the sense and RNAi vectors were constructed. We obtained thirty-one transgenic plants with 1 to 7 copies of T-DNA inserts of sense Mi from two nematode susceptible tomato cultivars as assayed by PCR and Southern blot analysis. RT-PCR analysis revealed that expression levels of Mi gene were varied in different transgenic plants. Nematode assays showed that the resistance to root-knot nematodes was significantly improved in some transgenic lines compared to untransformed susceptible control, and the resistance was inheritable in their selfed progenies. Loss of function via RNAi further confirmed the role of the Mi gene, and the original resistant lines became susceptible to root-knot nematodes.
	TO cite this article:Chen Rugang,Zhang Liying,Zhang Junhong, et al. Functional characterization of a Root-knot nematode resistance gene Mi from tomato (Lycopersicon esculentum L.)[OL].[29 March 2006] http://en.paper.edu.cn/en_releasepaper/content/5980


	5. Complex antimicrobial agent Ag-carboxymethyl chitosan-thiabendazole: Structure, properties and application in water-soluble coatings
	Xia Jinlan,Wang Chun,Nie Zhenyuan,Peng An’an,Guan Xin
	Biology 29 April 2005
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	Abstract:he structure, properties, and application in water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole (Ag-CMCTS-TBZ) prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free –NH2 groups and the –OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in content of silver ions in the complex agent improved in some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MIC of the complex agent to Esherichia coli, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 20~80, 15~60, 20~55, 40~250, and 400~1700 mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion pain
	TO cite this article:Xia Jinlan,Wang Chun,Nie Zhenyuan, et al. Complex antimicrobial agent Ag-carboxymethyl chitosan-thiabendazole: Structure, properties and application in water-soluble coatings[OL].[29 April 2005] http://en.paper.edu.cn/en_releasepaper/content/1964


	6. Preparation, optical properties and cell staining of water soluble amine-terminated PAMAM G2.0-Au nanocomposites
	Xia Jinlan,Fu Jindian,Nie Zhenyuan,Shen Li
	Biology 27 April 2005
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	Abstract:he solution chemical and optical characteristics of formation of NH2-PAMAM G2.0-Au nanocomposites in the aqueous solution of amine-terminated polyamidoamine dendrimer G2.0 (NH2-PAMAM G2.0) under various mole ratios of Au(III)/PAMAM were studied by both UV-Vis spectrometry and fluorospectrometry. The NH2-PAMAM G2.0-Au nanocomposites, with a type of structure in which one Au nanoparticle was surrounded by several NH2-PAMAM dendrimers, emitted strong bluish violet fluorescence, and were uniform, water soluble and biocompatible as well as very stable in frozen conditions. The sizes of gold nanoparticles in the nanocomposites were about 2.5nm and decreased with increase of NH2-PAMAM G2.0 concentration. The NH2-PAMAM G2.0 played an important role in being as host or micro-reactor for Au(Ⅲ) before Au(Ⅲ) reduction and being as dispersant and stabilizer for gold nanoparticles after Au(Ⅲ) reduction. Preliminary experiments of cells staining to human embryonic lung fibroblast (HELF) cell lines s
	TO cite this article:Xia Jinlan,Fu Jindian,Nie Zhenyuan, et al. Preparation, optical properties and cell staining of water soluble amine-terminated PAMAM G2.0-Au nanocomposites[OL].[27 April 2005] http://en.paper.edu.cn/en_releasepaper/content/1949

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