Construction of human monoclonal single-chain Fv antibodies against small-cell lung cancer by phage display libraries derived from cell-immunized SCID mice engrafted with human peripheral blood lymphocytes

In this study, we describe a phage display strategy to obtain human monoclonal single-chain Fv (scFv) antibodies binding target cancer cell surface proteins. By developing a cancer cell immunization protocol for SCID mice engrafted with human peripheral blood lymphocytes in combination with an antibody phage display method, we have isolated phage antibodies binding small-cell lung cancer cell line H889 by subtractive selection. One of the isolated scFv antibodies, 12EAb, recognized the E2 component of pyruvate dehydrogenase complex (PDC-E2) by immunoprecipitation according to MALDI-TOF MS analysis. Furthermore, we have confirmed the plasma membrane localization of PDC-E2 in small-cell lung cancer cells by immunocytochemistry and cell surface protein biotinylation, although PDC-E2 is usually located in the mitochondrial matrix. These results, including unique localization of identified antigens, were obtained by proteomic approaches. The present methods can be applied to generate human monoclonal scFv antibodies against tumor cells and to identify new molecular targets for immunotherapy and markers for diagnosis.     

Responses of the reflectance indices PRI and NDVI to experimental warming and drought in European shrublands along a north-south climatic gradient

The aim of this study was to evaluate the use of ground-based canopy reflectance measurements to detect changes in physiology and structure of vegetation in response to experimental warming and drought treatment at six European shrublands located along a North-South climatic gradient. We measured canopy reflectance, effective green leaf area index (green LAIe) and chlorophyll fluorescence of dominant species. The treatment effects on green LAIe varied among sites. We calculated three reflectance indices: photochemical reflectance index PRI [531 nm; 570 nm], normalized difference vegetation index NDVI₆₈₀ [780 nm; 680 nm] using red spectral region, and NDVI₅₇₀ [780 nm; 570 nm] using the same green spectral region as PRI. All three reflectance indices were significantly related to green LAIe and were able to detect changes in shrubland vegetation among treatments. In general warming treatment increased PRI and drought treatment reduced NDVI values. The significant treatment effect on photochemical efficiency of plants detected with PRI could not be detected by fluorescence measurements. However, we found canopy level measured PRI to be very sensitive to soil reflectance properties especially in vegetation areas with low green LAIe. As both soil reflectance and LAI varied between northern and southern sites it is problematic to draw universal conclusions of climate-derived changes in all vegetation types based merely on PRI measurements. We propose that canopy level PRI measurements can be more useful in areas of dense vegetation and dark soils.     

抗克伦特罗单链抗体可溶性表达及特性鉴定

目的:表达抗克伦特罗(CBL)可溶性单链抗体(scFv)并进行抗原结合活性鉴定。方法:利用呈现scFv的重组噬菌体感染大肠杆菌HB2151,IPTG诱导可溶性scFv表达。渗透休克法提取菌体细胞周质腔中scFv。经SDS-PAGE、Western-Blotting以及间接ELISA法分析检测可溶性scFv的表达,并采用间接竞争ELISA法鉴定scFv的抗原结合活性。结果:细菌培养上清及周质腔中均有抗CBL可溶性scFv表达,其分子量约为29kD;上清液及周质腔中scFv效价分别为1:80,1:1600,能够被CBL竞争性抑制,IC50分别为0.78、0.95ng/ml。结论:可溶性抗CBLscFv在大肠杆菌HB2151中获得成功表达,表达的scFv与CBL具有很好的结合活性,可用于进一步建立CBL相应的免疫学检测方法。     

Photostimulated luminescence studies of γ-irradiated KBr1−xIx:TlI mixed crystals

Results on photoluminescence and photostimulated luminescence studies of KBr_1−xI_x:TlI (0.01 and 0.05 mol%) mixed crystals grown in vacuum and air are presented. Photoluminescence spectra of the mixed crystals excited in the A-absorption band of KBr:Tl⁺ exhibited the characteristic emission bands of Tl⁺ ions in KBr:Tl⁺. When excited in the low energy tail of A-band absorption, additional emission bands were observed. Compared with earlier reports, excitation bands observed around 4.8, 4.6 and 4.4 eV are attributed to complex thallium centres of the form TlBr_6−nI_n (n = 0, 1, 2, 3). Photostimulated luminescence of γ-irradiated KBr_1−xI_x:TlI mixed crystals showed the presence of emission bands similar to the characteristic photoluminescence of Tl⁺ ions. The photostimulated luminescence slightly shifted towards the low energy side with increasing iodide composition x. The mechanism of emission in these mixed crystals is discussed. Dose response and storage stability (fading characteristics) in these mixed crystals are reported.     

Self-assembled rings of EuBr2 nanostructures

The EuBr₂ nanostructures self-assembled (SA) in ring form are presented in this letter. The atomic force microscopy (AFM) images show rings of ~ 190 to 2500 nm diameter formed on [100] surface. The sample optical response with rings displays an emission band peak (EBP) at 435 nm. The europium absorption bands reveal structural changes and shift toward infrared wavelength. The emission bandwidth of EuBr₂ nanostructures in ring form is narrower than dispersed nanostructures of similar size. To our knowledge, is the first time that there is clear evidence of the arrangement in ring form in the KBr:Eu²⁺ crystal samples.     

温光处理对节瓜幼苗光合作用的影响

试验以江心4号节瓜为试材,研究了温光处理对节瓜苗期叶片光合作用的影响,结果表明:低温导致了叶片光合色素含量明显降低,且随处理时间的延长而下降;低温下强光促进光合色素含量降低。低温处理下叶绿素a/叶绿素b比值明显提高,且随处理时间的延长而上升。低温下叶绿体类囊体解体、排列无序、联结断开,基粒片层肿涨,淀粉粒、质体球增加,淀粉粒体积变大;持续低温强光导致了叶绿体膜的解体;常温弱光下类囊体排列混乱、质体球增加。低温下叶片Fv/Fm明显下降,低温下强光明显降低Fv/Fm。低温、强光都会造成Fv/Fo的下降,而且低温和强光存在互作。低温下乙醇酸氧化酶活性上升,低温下强光增强了乙醇酸氧化酶活性,低温下较强的光呼吸有利于防御低温光抑制造成的伤害。     

调整处理对Fv520(B)不锈钢组织与性能的影响

采用TEM、XRD、金相分析等手段研究了Fv520(B)不锈钢经1050℃固溶处理后,在750～850℃温度范围内中间调整处理对组织、性能的影响。结果表明:调整处理过程中有NbC、M7C3型碳化物析出。随调整处理温度升高、时效温度降低,强度提高,而残余奥氏体量的变化则呈相反趋势。调整处理温度对时效析出相种类影响不大。850℃+480℃可获得最佳的强化效果,750℃+620℃处理可获得最佳的抗H2S应力腐蚀性能。     

Ultra-thin zinc oxide film on Mo(100)

Zinc oxide films on a single crystal Mo(100) substrate were fabricated by annealing the pre-deposited metal Zn films in 10^− 5-10^− 4 Pa O₂ ambience at 300-525 K, and were characterized by in situ Auger electron spectroscopy, electron energy loss spectroscopy, low energy electron diffraction and high-resolution electron energy loss spectroscopy. The results show that the atomic ratio of oxygen to zinc in zinc oxide film is significantly dependent on sample annealing temperature and O₂ pressure. A stoichiometric zinc oxide film has been obtained under ∼10^− 4 Pa O₂ at about 400 K. A redshift of Fuchs-Kliewer phonon energy correlated with surface oxygen deficiency is observed.     

时效处理对Fv520（B）钢抗H2S应力腐蚀性能的影响

采用Ｘ射线衍射 ,ＴＥＭ、ＳＥＭ等研究了时效温度对Ｆｖ５２０（Ｂ）钢组织、力学性能及抗Ｈ２Ｓ应力腐蚀性能的影响。结果表明：在４７０－６２０℃时效温度范围内,随温度升高,该钢的强度下降,残余奥氏体含量增加,抗Ｈ２Ｓ应力腐蚀能力增强。该钢抗Ｈ２Ｓ应力腐蚀性能与时效相形态,马氏体基体回火程度及残余奥氏体数量有关。