翘嘴鳜铜锌超氧化物歧化酶基因的分子克隆与原核表达

运用RT-PCR和RACE-PCR技术克隆了翘嘴鳜(Siniperca chuatsi)铜锌超氧化物歧化酶(命名为ScCu/Zn-SOD)基因,该基因的cDNA序列全长为804bp,开放阅读框为465bp,编码154个氨基酸。氨基酸序列中含2个Cu/Zn-SOD标签序列、7个铜锌金属结合位点、2个半胱氨酸位点和1个N-糖基化位点;其与胞内Cu/Zn-SOD(icCu/Zn-SOD)和胞外Cu/Zn-SOD(ecCu/Zn-SOD)氨基酸序列的同源性分别为60.13%~92.21%和33.77%~42.21%。在系统进化树中,ScCu/Zn-SOD与其它物种的icCu/Zn-SOD聚成一支。ScCu/Zn-SOD的蛋白晶体结构主要由2个α螺旋和8个β折叠组成,呈β折叠构象,通过结合1个Cu2+和1个Zn2+构成其酶活性中心。ScCu/Zn-SOD的mRNA在翘嘴鳜肌肉、鳃、肝脏和肾脏等组织中均有表达,且鳃中的相对表达量最高。将该基因编码蛋白序列与pET-30a表达载体重组,热激转入大肠杆菌BL21(DE3)感受态细胞中诱导表达,SDS-PAGE检测发现诱导后菌液的超声上清中有可溶性重组蛋白表达。     

Surface-enhanced Raman scattering of 4-mercaptobenzoic acid and hemoglobin adsorbed on self-assembled Ag monolayer films with different shapes

Polyvinylpyrrolidone (PVP)-protected silver nanostructures of various shapes, including nanocubes, nanospheres, and hybrid shapes with nanospheres and nanorods, on the surface of glass or Si substrates (PVP-Ag films) are prepared by using electrostatic self-assembly. With 4-mercaptobenzoic acid (4-MBA) as a probe molecule, it is demonstrated that the PVP-protected silver nanocubes films (PVP-Ag NCs) have better surface-enhanced Raman scattering (SERS) activity with an order of magnitude larger enhancement factors (EF) than the PVP-protected silver nanospheres films and the PVP-protected silver hybrid shapes films, which is confirmed by our numerical simulations. The EF of 4-MBA on the PVP-Ag NCs film are up to ~5.38 × 10⁶, and the detection limit is at least down to ~10^?8 M. The uniformity and reproducibility of the SERS signals on PVP-Ag NCs film are tested by point-to-point and batch-to-batch measurements. Meanwhile, the PVP-Ag films are also shown to be an excellent SERS substrate with good biocompatibility for hemoglobin detection. It is shown that the PVP-Ag NCs films can be used as excellent SERS substrate with good activity, uniformity, reproducibility, and biocompatibility and are promising for a myriad of chemical and biochemical sensing applications.     

Parameter determination from current–voltage characteristics of HgCdTe photodiodes in forward bias region

Current–voltage characteristics of HgCdTe photodiodes in the forward bias region have been modeled considering mechanisms including drift-diffusion current, recombination current, metal-semiconductor contact and constant series resistance. Moreover, a fitting method based on the genetic algorithm has been developed to obtain values of related physical parameters from the measured dynamic resistance–voltage curves. Fitting results of $n^+$ -on- $p$ planar devices with different cutoff wavelengths are presented to illustrate the model and method, which are available and promising in acquiring device parameter values and evaluating the electrode contact quality.     

Photoinduced charge injection in the metal/organic interface studied by transient photovoltage measurements with bias

Transient photovoltage of ITO/organic/Al cells is studied under different bias polarities and voltages.It is found that for an ITO/NPB/Al cell,light incidence on the Al side induces more bias-dependent transient photovoltage variation when the photovoltage is positive than when it is negative.However,for an ITO/C60 /Al cell,the variation characteristics of transient photovoltage is reversed.These results support the previously proposed mechanism that Al could inject charges into the organic layer upon photon excitation,indicating that the absorption of electrode can also contribute to photovoltaic effect.     

Label-free high-throughput and real-time detections of protein interactions by oblique-incidence reflectivity difference method

Selected Mouse IgG of 1 mg/mL as target was fabricated on microarray for 500 sample dots.Label-free and real-time reaction dynamic processes were detected between the microarrays with Goat Anti-mouse IgG of 0.02 mg/mL using the obliqueincidence reflectivity difference(OIRD)method.We obtained the reaction results and the reaction dynamic curves of 500 protein dots.In addition,we also used label-free detection of protein microarrays of 10080 sample dots,including BSA and different concentrations of Mouse IgG and Rabbit IgG,by OIRD.The obtained reaction results between the protein microarray with 1 mg/mL Goat Anti-mouse IgG and 1 mg/mL Goat Anti-rabbit IgG are reported herein.Experimental results show that OIRD can be not only label-free high-throughput detection method for biological microarrays but also label-free real-time detection in the interaction processes of biomolecules.     

The intruder orbitals in superdeformed bands and alignment additivity of odd–odd nuclei in the region

The particle-number conserving (PNC) method for treating the cranked shell model with monopole and quadrupole pairing correlations is used to study the superdeformed (SD) bands observed in odd–odd nuclei in the A190 mass region. Spins are assigned to the levels in these bands. The microscopic mechanism of the ω evolution of the dynamic moment of inertia J⁽²⁾ for these SD bands are analyzed. In particular, the major roles of the j_15/2 neutron and i_13/2 proton orbitals played in the SD bands are investigated in detail by contributions to J⁽²⁾ from each cranked orbital and interference terms between two cranked orbitals. Additivity in the A190 mass region is investigated. The experimental evidence for additivity of alignments in ¹⁹²Tl can be reproduced by our calculations.     

一种用于土壤非金属养分测试的光纤探头式分光光度计

针对测土配方施肥技术中要求快速、便捷、高效地进行土壤养分测试的需求,文章基于浸入式光纤探头、平场凹面全息光栅、二极管线阵检测器开发了一种光纤探头式分光光度计用于土壤养分中非金属元素的快速、准确测试。基于国家计量检定规程JJG 178—2007对紫外、可见、近红外分光光度计的性能检测方法测试的该仪器的波长最大允许误差与波长重复性、基线平直度、透射比最大允许误差与透射比重复性均达到了国标第Ⅲ级别标准,其最小光谱带宽、噪声与漂移、杂散光基本达到了国标第Ⅳ级别标准。基于该仪器测试的土壤硝态氮、铵态氮、有效磷、有效硫、有效硼、和有机质含量与基于商用的国产单光束和进口双光束分光光度计测试的结果呈极显著的线性相关关系,其回归方程的斜率接近于1,且对比数据之间无显著性差异。因此,该光纤探头式分光光度计可用于土壤非金属养分的快速、准确测试。     

RF and field measurements of the SSC-LINAC RFQ

The 53.667 MHz continuous-wave heavy ion RFQ has been designed and manufactured for the SSC-LINAC project.This four-rod RFQ accelerates ions with maximum mass to charge ratio of 7 from 3.728 keV/u to 143 keV/u.Measurements have been carried out to check the RF performance of the cavity and the quality of the electric field.The S11 of the power coupler is adjusted to better than-44 dB,and the Q0 of the cavity is 6440.The quality of the electric field is evaluated by the perturbation method.The measurement procedure and data analysis will be discussed in detail.The error due to gravity of the perturbation bead has been corrected by averaging the fields in different quadrants.As a result,the unflatness of the electric field is±2.5%,and the dipole field component distributes from 0%to 20%in different longitudinal positions,which indicates the asymmetry of the quadrupole field.The unflatness of the quadrupole field distribution represents a good agreement with the simulation results.High power RF test and beam commissioning of the RFQ are on schedule in early 2014.