Mutation Breeding of Lycopene-Producing Strain Blakeslea Trispora by a Novel Atmospheric and Room Temperature Plasma (ARTP)

To improve the fermentation efficiency of lycopene, a plasma jet, driven by an active helium atom supplied with atmospheric and room temperature plasma (ARTP) biological breeding system, was used as a new method to generate mutations in Blakeslea trispora (?). After several rounds of screening, a mutant A5 with high concentration of lycopene and dry biomass was isolated, which showed a maximum lycopene concentration (26.4?±?0.2 mg/g dry biomass) which was 55 % higher than the parent strain (16.9?±?0.3 mg/g dry biomass) in the production of lycopene. Compared with parent strain, B. trispora A5 required less dissolved oxygen (10 % less than that of parent strain) to reach maximum concentration in a 5-L stirred tank reactor batch fermentation.     

Essential Role of the N- and C-terminals of Laccase from Pleurotus florida on the Laccase Activity and Stability

POXA1b is the most thermostable laccase isoenzyme from Pleurotus ostreatus. POXA1b is remarkably stable at alkaline pH (the t_1/2 at pH 10 was 30 days), and its C-terminal affects its catalytic and stability properties. We cloned POXA1c from P. florida, which showed 99 % identity with POXA1b. POXA1c was functionally expressed in Pichia pastoris. The functions of the N and C termini of POXA1c were investigated using site-directed mutagenesis. Compared with POXA1c, the N-terminal R5V site effectively increased the specific activities for 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and guaiacol by 2- and 3.5-fold, respectively. A C-terminal truncated mutant, POXA1c△13, also increased the specific activities for ABTS and guaiacol by 2.3- and 3.4-fold, respectively. A double mutant, POXA1cΔ13-R5V, combined the R5V and △13 effects. The specific activity of this double mutant for ABTS was 1,321 U/mg, which indicated a 4-fold increase compared with the wild type. The role of residue V5 on laccase catalytic properties was also observed for laccases from Trametes versicolor and Rigidoporus lignosus. The specific activities of the V5R of the laccases from T. versicolor and R. lignosus were half of that of the wild type. The pH and thermal stability analysis of POXA1c and its mutants showed that the enzymes were remarkably stable because they showed 63 % residual activity after incubation for 108 h at 30 °C over a pH range of 4.5 to 9.0. Similar results were observed for POXA1cΔ13-R5V. POXA1cΔ13-R5V can be widely used in industrial biotechnology because of its excellent catalytic properties.     

Enhanced Enzymatic Hydrolysis of Palm Pressed Fiber Based on the Three Main Components: Cellulose,Hemicellulose, and Lignin

The enzymatic hydrolysis of the native and the pretreated palm pressed fiber (PPF) was deeply investigated by using the enzyme cocktail ACCELLERASE 1500. Together with the spent PPF from the first hydrolysis and the further doubly-treated PPF, the proportions of three main components were determined and analyzed based on a triangle figure. The proportion (cellulose/hemicelluloses/lignin) in the spent PPF was equal to 44:23:33 and the surface morphology of the spent PPF looks very similar to the native PPF surface showing poor hydrolysis efficiency. After further double treatment, the proportion was changed evidently from the original 44:23:33 to 54:21:25 and the surface structure was significantly disrupted showing a potential to be hydrolyzed completely. Additionally, all samples were characterized by Fourier transform infrared spectroscopy and X-ray diffractogram through considerations of alkaline solution treatment, so as to understand better the nature of biomass hydrolysis, from the aspect of three biomass components.     

Apoptosis in BEL-7402 cells induced by ruthenium(II) complexes through a ROS-mediated mitochondrial pathway

Three Ru(II) polypyridyl complexes [Ru(dmb)₂(HMSPIP)](ClO₄)₂ (1), [Ru(phen)₂(HMSPIP)](ClO₄)₂ (2) and [Ru(dmp)₂(HMSPIP)](ClO₄)₂ (3) were synthesized and characterized. The cytotoxicity in vitro, apoptosis, cell cycle arrest, reactive oxygen species and mitochondrial membrane potential were assayed. The IC₅₀ values of complexes 1, 2 and 3 toward BEL-7402, A549, MG-63 and SK-BR-3 cell lines ranged from 10.9 ± 1.6 to 42.0 ± 3.4 μM. Complexes 1, 2 and 3 can effectively induce apoptosis and inhibit the growth of BEL-7402 cells at the G2/M phase. These complexes can enhance the level of reactive oxygen species and induce decrease in the mitochondrial membrane potential. Additionally, complex 2 can down-regulate the expression of antiapoptotic protein of Bcl-2 protein and up-regulate the levels of proapoptotic protein Bim in BEL-7402 cells.     

Crystal structures, magnetic, dielectric and ferroelectric properties of two copper(II) complexes with m-nitrobenzoic acid

Reactions of CuCl₂, m-nitrobenzoic acid (HNBA) and NaOH with 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) in aqueous ethanol afforded two Cu(II) complexes Cu(bpy)(NBA)₂, 1, and [Cu(phen)(H₂O)₂(NBA)](NBA), 2. The monomolecular Cu(bpy)(NBA)₂ moieties are both bridged by hydrogen bonding interactions and interlayer π ^*–π ^*stacking interactions to form a 3D (3,4,6)-connected supramolecular architecture with the Schäfli symbol of (4⁴·6²)(4⁴·6⁶·8⁵)(6³)₂. Complex 2 crystallizes in a noncentrosymmetric space group P2₁ where all molecules show the same orientation along the polar b axis. Preliminary investigations suggest that 2 exhibits ferroelectric hysteresis loops at room temperature with remanent polarization (P _r) of ca. 0.09 μC cm^?2 and coercive electric fields of 2.53 kV cm^?1, respectively. It may be a potential ferroelectric with a relatively large spontaneous polarization (P _s) of 0.22 μC cm^?2. Furthermore, permittivity property measurements reveal a dielectric constant (ε _r) of 6.36. Variable-temperature (2–300 K) magnetic susceptibility measurements showed the presence of weak ferromagnetic interactions between the Cu(II) ions for both 1 and 2.     

Preparation of raspberry-like silica microcapsules via sulfonated polystyrene template and aniline medium assembly method

Raspberry-like composite particles and microcapsules were prepared with anionic sulfonated polystyrene (PSS) particles as templates and cationic aniline monomer as assembly medium. With the help of the sulfonated microgel shells, aniline and silica particles could not only adsorbed onto template surfaces but also go inward shells and finally form microcapsules with varied silica shell thickness. The sulfonation extent of PSS particles first climbed up and then decreased with sulfonation time due to the competition of sulfonation reaction and PSS chain detachment. The silica content in composite particles and shell thickness of microcapsules followed similar trend with sulfonation extent. The choice of aniline as assembly medium was checked by comparing with methyl methacrylate and [2-(methacryloyloxy) ethyl] trimethylammonium chloride, and it was found that the cationic and water-insoluble properties of aniline are both important for the composite efficiency.     

石墨烯表界面化学修饰及其功能调控

石墨烯属于碳纳米材料家族中的一员,是一种单层的二维原子晶体,具有高硬度、高导热性、高载流子迁移率等诸多优良特性,被认为是新一代电子学器件的重要基础材料.近年来我们课题组利用石墨烯的这些优良特性在其表界面化学修饰及其功能调控方面开展了一系列研究工作.我们对石墨烯表界面进行了共价或非共价化学修饰,在一定程度上打开了石墨烯的带隙,并发展了具有传感功能的石墨烯器件.我们还制备了基于石墨烯的纳米电极,发展了新一代分子电子器件的普适性制备方法,实现了单分子器件的功能化.展望未来,以石墨烯为代表的碳基纳米材料将继续在纳电子器件研究领域发挥重要作用.     

气相色谱-质谱法测定人血液中的有机磷农药

建立了农药中毒人员血液中常见8种有机磷农药的气相色谱-质谱(GC-MS)分析方法。样品经二氯甲烷萃取后,经冷冻、高速离心除脂,采用GCMS结合选择离子监测模式(SIM)定性,外标法定量。结果表明,各种目标物质在0.05~1 mg/L(除甲胺磷0.1~2 mg/L和敌百虫1~20 mg/L外)范围内的线性关系良好,相关系数r≥0.9980;平均回收率为60.6%~113.3%,相对标准偏差小于19%;检出限为3.0~60μg/L。方法可以满足血液中多种有机磷农药的同时分析要求,可为有机磷农药中毒患者提供诊断依据。     

微流控芯片非接触电导法测定注射液中的门冬氨酸鸟氨酸

建立了微流控芯片非接触电导检测法快速分离检测门冬氨酸鸟氨酸注射液中门冬氨酸鸟氨酸的分析方法。考察了缓冲溶液的种类和浓度、添加剂、进样时间、分离电压等因素对分离检测的影响。在优化条件下,即以4 mmol/L M ES-6 mmol/L(L)-His(p H 4.5)为缓冲溶液,分离电压2.00 k V、进样时间10 s,1 min内可实现较好的分离和检测,门冬氨酸鸟氨酸的线性范围为20~200μg/m L,相关系数为0.9990,检出限(S/N=3)为10.0μg/m L,RSD为1.9%,加标回收率为97.6%~101.3%。方法可用于门冬氨酸鸟氨酸的质量控制。     

基于磷钼酸和2-(2-羟基苯)苯并咪唑复合物的晶体结构和质子导电性(英文)

以磷钼酸和2-(2-羟基苯)苯并咪唑(L)为原料制备了具有质子导电性的有机-无机化合物[H3L2(PMo12O40)·7H2O·4CH3OH]n(1).单晶X射线衍射分析结果表明化合物1具有基于磷钼酸、2-(2-羟基苯)苯并咪唑及溶剂甲醇分子的二维氢键网络结构;质子导电性能测试结果表明该化合物在100℃、相对湿度为98%时的电导率达到10-4 S·cm-1.