Biologically diverse molecular variants within a single HIV-1 isolate

AIDS is a disorder characterized by a slow progressive impairment of immune function and by infection of human immunodeficiency viruses (HIV-1, HIV-2). Our knowledge of how these viruses cause disease in man, or how the related lentiviruses (visna and equine infectious anaemia virus) cause disease in animals, is still fragmentary. In particular, the significance of genetic variation in HIV-1, occurring within populations, within individuals and over periods of time, and the mechanisms of viral persistence remain unclear. To address these issues we prepared a series of proviral clones of HIV-1 originating from a single patient and compared their biological properties. Here we show that hybrid genomes (in which the envelope region of six viral clones were separately substituted into a prototype HIV-1 genome) generated viruses with widely differing capacity to grow in human T cells, cell lines and monocytoid cultures. These data suggest that extensive biological variation exists in vivo within an infected individual and is in part determined at the level of the viral envelope.     

A naturally immunogenic virion-associated protein specific for HIV-2 and SIV

The genomic organization of HIV-1 and the family of HIV-2 and SIV viruses is similar. However, there is an open reading frame, orf-x, that is present in HIV-2 and SIV, but not in HIV-1. The extent of protein sequence conservation in orf-x between HIV-2ROD and SIVMAC suggests that this open reading frame encodes a gene that may be important for infectivity or replication. Here, we show that the orf-x products of SIVMAC and HIV-2SBL-6669 are virion-associated and that the introduction of a premature stop codon into orf-x, did not abrogate virus infectivity and replication in vitro. Antibody reactivity to the orf-x product was detected in 35 of 42 HIV-2 positive serum samples and 11 of 52 SIV seropositive monkeys. No such antibodies were detected in HIV-1 positive donors, blood donors seronegative for both HIV-2 and HIV-1, or SIV seronegative monkeys. This suggests that orf-x is dispensable for in vitro replication of SIVMAC and that the orf-x gene product of HIV-2 or its antibody can be used to distinguish HIV-2 from HIV-1 infection.     

波莱尔发散级数的积分可和思想研究

目的探讨波莱尔(E.Borel,1871—1956)的积分可和方法的思想来源、思想演变过程及重要影响。方法历史分析和文献考证。结果波莱尔的积分可和法是他在受到萨塞罗(E.Cesaro,1859—1906)工作的影响下,在指数可和法的基础上自然提出的。结论积分可和思想对当时的一些数学家有重要影响。该法在函数解析开拓、微分方程中有重要意义。     

关于电子质量的发散疑难

从电子结构的特点、经典电动力学的局限性以及电磁质量的特性等三个方面对电子质量发散疑难进行了分析和讨论,结果表明,导致电子质量发散是因为：把电子简单地视为无限度的几何点;经典电动力学的局限性;混淆了电子总质量与电磁质量的概念。     

改性大豆分离蛋白冰淇淋的研究

采用热改性和酶改性两种改性方法,提高大豆分离蛋白的乳化性,使其适于添加到冰淇淋中。最终确定了转谷氨酰胺酶改性大豆分离蛋白添加到冰淇淋中效果最好,其配方为：TG改性SPI5％,白砂糖12％,奶粉8％,奶油3％,CMC0．1％,单甘酯0．1％,明胶0．2％,成型后冰淇淋膨胀率为63．4％,融化率为52．75％,各项指标都令人满意。     

基于Schiff碱结构的高效识别Cu~(2+)的比色化学传感分子

使用一个含Schiff碱结构的萘胺类衍生物作为比色传感分子L,通过紫外可见分光光度计进行金属离子的识别性研究.研究表明:L在乙醇与水(体积比1∶1)的溶液中能对Cu2+实现专一的选择性识别,溶液的颜色由黄色变为无色,可进行裸眼识别,L对Cu2+的最低检测限达到0.224μmol/L.通过Job’s曲线测试表明:L与Cu2+形成摩尔比1∶1的稳定配合物,且络合常数为1.483×105L·mol-1.     

模拟人类发散思维的测度值马尔可夫理论模型

本文提出测度值马尔可夫决策过程新模型.在此模型下,agent对环境的把握用测度概念来表示,于是agent则根据测度来决定自己的最优行动以得到最优策略,因此本文也提供了测度值马尔可夫决策过程的最优策略算法.该模型是部分可观察马尔可夫决策过程的推广,它反映人类思维的一个重要特征,人们在把握全部状态可能性(即对状态空间进行权衡度量)的态势下,思考问题并选择自己的最优行动.部分可观察马尔可夫决策过程只是它的一种特例.     

2—（2—噻吩偶氮）—5—二乙氨基酚高灵敏分光光度法测定痕量镍

在ｐＨ５４～７５范围内，镍与２（２噻吩偶氮）５二乙氨基酚（ＴＡＤＡＰ）形成最大吸收波长位于５６３ｎｍ的红色配合物，显色反应具有很高的灵敏度，摩尔吸光系数为１５６×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，并且色泽稳定，在０～１５μｇ／２５ｍＬ范围内符合比耳定律．该方法可用于铝合金中镍的测定．     

Nucleotide sequence of RNA2 and polyprotein processing sites of a Chinese isolate of broad bean wilt virus 2

RNA2 of broad bean wilt virus 2 (BBWV2) isolate B935 is composed of 3601 nucleotide (nt) residues, exclusive of the polyadenylate at the 3' end. Only one of the six possible reading frames has a long open reading frame, which extends from nt 231 to nt 3428 in the polarity of encapsidated RNA, and encodes a polyprotein of 119 kD. The N-terminus of the large coat protein (LCP) is located at 599 nt and the small coat protein (SCP) at 197 nl from the C-terminus of the 119 kD protein, which suggests that the coat proteins are released from the polyprotein by cleavages of a glulamine-glycine (Q-G) and a glutamine-alanine (Q-A) bond respectively. The sequence comparison of B935 with fabaviruses shows that B935 has very high sequence homology with other BBWV2 isolates and with patchoul' mild mosaic virus, but has lower homology with BBWV1 isolates. B935 has a similar genomic organization, but a low sequence homology to RNA2 molecules of comoviruses and nepoviruses.     

新型苊并吡嗪类高灵敏度极性探针

以苊醌为原料,经溴化、环构化和芳香亲核取代反应合成了一种新型的以苊并吡嗪为母体的极性荧光探针3-正丁胺基-苊并吡嗪-8,9二腈(A)。探针A的荧光强度随着溶剂极性的增加显著降低,从四氯化碳(Φf=0.364 2)到乙腈(Φf=0.000 6)荧光量子产率减弱超过600倍,从四氯化碳(533nm)到N,N-二甲基甲酰胺(651nm)最大发射波长红移了118nm。利用探针A对极性敏感来检测有机溶剂中的水含量,建立了一种新的四氢呋喃和1,4-二氧六环中水含量荧光分析方法,最低检测限分别为0.019%和0.0076%。     

SnO2纳米线阵列的制备及纳米器件的制作

采用简单的溶胶-凝胶方法在多孔阳极氧化铝模板(AAM)的微孔中制备了高度有序的SnO2纳米线阵列。XRD,SEM和TEM对样品进行了结构和形貌的表征,结果表明,高度有序的SnO2纳米线具有四方相的多晶结构,纳米线连续均匀;并对SnO2纳米线阵列的生长机理进行了探讨;最后用聚焦离子束沉积设备制作了单根SnO2纳米线器件。     

高分散TiO2-SiO2复合氧化物的制备及其光催化性能

利用溶胶-凝胶技术,控制钛酸四丁酯（TBOT）与硅酸乙酯（TEOS）的水解速度,使其共同水解为溶胶、凝胶,以乙醇为溶剂进行干燥,经过热处理后,得到高分散的纳米TiO2-SiO2复合氧化物。应用TEM,FTIR,XRD,DRS对其进行了表征,表明TiO2均匀地分散于无定形SiO2基质中,以Ti—O—Si键结合。此催化荆在对环己烷光催化氧化反应中显示了对环己醇良好的选择性。     

Human infection by genetically diverse SIVSM-related HIV-2 in west Africa.

Our understanding of the biology and origins of human immunodeficiency virus type 2 (HIV-2) derives from studies of cultured isolates from urban populations experiencing epidemic infection and disease. To test the hypothesis that such isolates might represent only a subset of a larger, genetically more diverse group of viruses, we used nested polymerase chain reactions to characterize HIV-2 sequences in uncultured mononuclear blood cells of two healthy Liberian agricultural workers, from whom virus isolation was repeatedly unsuccessful, and from a culture-positive symptomatic urban dweller. Analysis of pol, env and long terminal repeat regions revealed the presence of three highly divergent HIV-2 strains, one of which (from one of the healthy subjects) was significantly more closely related to simian immunodeficiency viruses infecting sooty mangabeys and rhesus macaques (SIVSM/SIVMAC) than to any virus of human derivation. This subject also harboured multiply defective viral genotypes that resulted from hypermutation of G to A bases. Our results indicate that HIV-2, SIVSM and SIVMAC comprise a single, highly diverse group of lentiviruses which cannot be separated into distinct phylogenetic lineages according to species of origin.