低温荧光摄影技术的进一步探索

低温荧光摄影技术在物证检验中的应用具有非常广阔的前景。本文进一步探索了物质的荧光特性及其研究方法，低温荧光摄影的类型及其吸收滤光技术。     

Real time observation of the photocleavage of single DNA molecules

A method for real time observation of photo-cleavage of stratched λDNA at single molecular level by a fluorescent microscope coupled with CCD is developed.DNA molecules stained with YOYO-1 are stretched by the mo-lecular combing technique and fixed on a modified slide.Then the Process of Photocleavage and relaxation of DNA under radiation of blue light is observed.We speculate that the conformation change of stretched DNA and the effect of water are likely to facilitate the effect of YOYO photocleav-age DNA molecules.The photocleavage effect of YOYO for stretched DNA may be useful to study DNA elasticity,cancer research as well as the interaction between DNA and dyes.     

pH Dependence of Chlorophyll States, Protein Structures and Function of the PSII Membranes

IntroductionPhotosystem II ( PSII) is a pigment- proteincomplex in the thylakoid membrane. Its reactioncenter( PSII- RC) ,which is composed of D1 andD2 proteins,generates the highly positive oxidantrequired for the oxidation of water by light- drivencharge separation. Water oxidation occurs at theMn4cluster positioned atthe center of the oxygen-evolving complex on the lumenal surface of PSII.In green plants,the highly reactive Mn4cluster isshielded by a number of extrinsic proteins( 33…     

氧氟沙星荧光光度法测定痕量铁

研究了在HAc-NaAc缓冲溶液中氧氟沙星与Fe(Ⅲ)的络合反应，结果表明：在pH=4．0的缓冲溶液中，氧氟沙星有稳定而较强的荧光；与Fe(Ⅲ)络合后，荧光强度减弱．最大激发及发射波长为324nm和498．6nm，Fe(Ⅲ)的质量浓度在0．56～3．08mg／L范围内，荧光强度与浓度呈良好的线性关系．检出限为0，076mg／L，常见的共存离子不干扰其测定．本方法用于水中痕量铁的测定，得到了满意的结果。     

苦杏仁酸-EDTA-CTMAB体系荧光法测定铽

研究了铽-苦杏仁酸-EDTA-CTMAB体系的荧光性质,探讨了荧光体系的组成及影响因素,建立了在该体系中测定铽的新方法.在pH值为12.6时,由于表面活性剂CTMAB的加入,使体系的相对荧光强度有较大的增强.在激发波长245 nm和荧光波长547 nm处测定铽,检测限达10 ng/ml.此法应用于合成样品中微量铽的测定,结果令人满意.     

N-terminal of L protein of vesicular stomatitis virus contains a new signal sequence

The L protein (241kD) of vesicular stomatitis virus (VSV) is the most important snbnnit of the replication complex. The existence of specific localization signal in the L protein was investigated by making recombinant constructs expressing truncated mutants of the L protein fused to green fluorescent protein (GFP) in transient transfection assays. The chimeric genes encoding varied N-terminal of L and GFP gene were put under the control of T7 promoter or CMV promoter. The fusion proteins were transiently expressed in BHK-21, COS-7, CHO or Hep G2 cells. When more than 120 residues were deleted or only 96 residues were kept on the N-terminal, the fusion proteins were shown to be distributed throughout the cells, cytoplasm and nucleus under the confocal microscope. However, other chimeric proteins with 120 or more amino acids were dotted and distributed in the perinuclear regions. And the fusion protein with 96—120 aa has the similar distribution. A thirteen-residue peptide QGYSFLHEVDKEA (108—120) was identified as localization signal, whose function would be absolutely distributed with the deficiency of D or V. Our results show that there is an independent localizing signal in N-terminal domain of L protein of VSV and this functional signal is conserved in different cell lines.     

Y^3＋,La^3＋对CaSO4：Eu^2＋发光性质的影响

用沉淀法合成了掺杂Y~(3 ),La~(3 )的CaSO_4:Eu~(2 )稀土发光材料,研究了材料的晶体结构和荧光光谱,根据实验结果,所制样品基本上属正交晶系、C_(2v)空间群,Eu离子在CaSO_4中的激发峰为基态到4f~65d(E_g),(T_(2g))激发态的跃迁;样品发射主峰位于383um,属于Eu~(2 )的~5P_(7/2)→~8S_(2/7)跃迁,说明样品中Eu离子主要以Eu~(2 )的形式存在。CaSO_4:RE(La,Y)本身没有荧光,Y~(3 ),La~(3 )掺入CaSO_4:Eu中未改变基质的晶型结构,但可增强CaSO_4:Eu中Eu~(2 )的荧光强度。     

氮素营养诊断方法的应用现状及展望

阐述了土壤、植物氮素营养诊断方法的原理、优缺点及其应用情况，提出应用高光谱遥感和叶绿素荧光进行氮素营养诊断的可能性，并对完善氮素营养诊断方法和拓宽诊断内容提出了见解。     

复配型微乳液介质苯基荧光酮光度法测定痕量铅的研究

研究了在微乳液介质中 ,在pH =9.5时 ,铅与苯基荧光酮 (PF)显色生成稳定的 1:3配合物 ,在 5 72nm处摩尔吸光系数为 6 .0 4× 10 4L·mol-1·cm-1,铅含量在 0～ 1.2 μg/mL范围内符合比尔定律 ,采用巯基葡聚糖凝胶分离富集 ,消除了共存离子的干扰 ,用所拟方法测定水样中的微量铅 ,结果满意     

金属离子与血清白蛋白结合反应研究进展

综述了金属离子与血清白蛋白结合反应的研究进展，简要介绍了研究中常用的紫外－可见光谱法、荧光光谱法以及平衡透析法。根据已发表的研究结果，对某些金属离子与血清白蛋白结合的位点、络合物的空间构型、结合数和稳定常数进行了总结，对金属离子与血清白蛋白之间的强结合位点进行了分类。最后讨论了此类研究中存在的问题和研究方向。