Differences in Variation of Human Immunodeficiency Virus Type 1 Sequences from Henan and Shanghai Regions of China

Illegally paid blood donation was a risk factor for HIV acquisition exclusively in Henan and Hubei Provinces of China,and not in Shanghai.Nucleotide sequences in the gag and env genes of HIV-1 were compared between isolates from Henan and Shanghai regions of China to test whether an expected higher degree of a common source of infections from this unique blood donation transmission risk would be evident as decreased variation among Henan isolates in an exploratory cross-sectional analysis.Among 38 isolates studied,23 of 23(100%)from Henan and 8 of 15(54%)from Shanghai were subtype B.In addition,fewer sequence differences were found in gp41 of subtype B isolates from Henan than from Shanghai isolates.Further studies with additional controls are therefore warranted to confirm the role of the degree of a common source of infections in differences in HIV variation across populations.     

Antiviral Effect of Interferon-Induced Guanylate Binding Protein-1 against Coxsackie Virus and Hepatitis B Virus B3 in Vitro

Guanylate binding protein-1(GBP-1)is an interferon-induced protein.To observe its antiviral effect against Hepatitis B virus(HBV)and Coxsackie virus B3(CVB3),we constructed an eukaryotic expression vector of human GBP-1(hGBP-1).Full-length encoding sequence of hGBP-1 was amplified by long chain RT-PCR and inserted into a pCR2.1 vector,then subcloned into a pCDNA3.1(-)vector.Recombinant hGBP-1 plasmids and pHBV1.3 carrying 1.3-fold genome of HBV were contransfected into HepG2 cells,and inhibition effect of hGBP-1 against HBV replication was observed.Hela cells transfected with recombinant hGBP-1 plasmids were challenged with CVB3,and viral yield in cultures were detected.The results indicated that recombinant eukaryotic expression plasmid of hGBP-1 was constructed successfully and the hGBP-1 gene carried in this plasmid could be efficiently expressed in HepG2 cells and Hela cells.hGBP-1 inhibit CVB3 but not HBV replication in vitro.These results demonstrate that hGBP-1 mediates an antiviral effect against CVB3 but not HBV and perhaps plays an important role in the interferon-mediated antiviral response against CVB3.     

GABA-C受体/通道的最新研究进展

目前已有很多关于GABA-C受体/通道在视网膜中功能的研究报道,但近年来发现它在哺乳动物的视网膜外的组织,如丘脑、海马、垂体、脊髓、小脑和胃肠道等也有表达并参与了相关激素的调控.本文将主要叙述GABA-C受体/通道在分子结构、分布和药理学特性方面较新的研究进展及参与相关激素包括褪黑激素、催乳素、生长激素和促甲状腺激素调控的研究.     

脱氮菌株P6的分离鉴定及其处理氨氮废水的试验研究

目的：从污水处理池的污泥中分离得到去除氨氮效果较好的菌株,对其进行分类鉴定和去除氨氮的最佳条件的研究。方法：根据维诺格拉斯基柱法分离出几种纯菌株,选取其中脱氮效果较好的一株,经形态观察和生理生化实验,鉴定其分类地位。研究不同培养条件对该菌生长的影响,用滴定法测定不同条件下其对氨氮的去除率。结果：获得一脱氮菌株P6,初步推测该菌为产碱杆菌。其最适生长条件为：温度29℃,初始pH值7.5以及摇床（100r/min）培养,且在温度29℃、废水的初始pH值11、接种量与废水体积的比例为1.2g/150mL、添加乙酸钠浓度为0.1%、废水的氨氮浓度为600mg/L和摇床（100r/min）的条件下,3d后该菌对氨氮的去除率达到45%。结论：P6菌有一定的去除氨氮能力,具有应用价值。     

Crystal structure of AGR_C_4470p from Agrobacterium tumefaciens

We report here the crystal structure at 2.0 A resolution of the AGR_C_4470p protein from the Gram-negative bacterium Agrobacterium tumefaciens. The protein is a tightly associated dimer, each subunit of which bears strong structural homology with the two domains of the heme utilization protein ChuS from Escherichia coli and HemS from Yersinia enterocolitica. Remarkably, the organization of the AGR_C_4470p dimer is the same as that of the two domains in ChuS and HemS, providing structural evidence that these two proteins evolved by gene duplication. However, the binding site for heme, while conserved in HemS and ChuS, is not conserved in AGR_C_4470p, suggesting that it probably has a different function. This is supported by the presence of two homologs of AGR_C_4470p in E. coli, in addition to the ChuS protein.     

The disulfide loop of gp41 is critical to the furin recognition site of HIV gp160

The importance of the HIV gp41 conserved disulfide loop to envelope function has been examined by mutational and functional analyses. Based on a luciferase-reporter entry assay, mutants gp41-CC/AA (C598A/C604A) and gp41-Delta (deletion of residues 596-606) result in a nonfunctional envelope protein. Western blot analysis shows both mutants to be properly expressed but not processed to form gp120 and gp41, which explains their nonfunctionality. The presence of mutant gp160 on the cell surface, as well as their ability to bind to sCD4, suggests that the mutations have disrupted processing at the furin recognition site encoded within the gp120 conserved domain 5, without resulting in an overall misfolding of the protein. With respect to the furin recognition site, the mutations are sequentially distant, which implies that the gp41 disulfide loop is interacting with gp120 C5 in gp160. In addition, we have modeled the gp120-gp41 interaction in unprocessed precursor gp160 using structural data available for gp120 and gp41 domains in isolation, supplemented by mutagenesis data. We suggest that the mutations have altered the interaction between gp120 C5 and the gp41 disulfide loop, resulting in decreased accessibility of the furin recognition site and implying that the interaction between the gp120 C5 and gp41 loop is a conformational requirement for gp160 processing. The sensitivity of this interaction could be exploited in future antivirals designed to disrupt HIV pathogenesis by disrupting gp160 processing.     

Synthesis and in vitro evaluation of tetrahydroisoquinolinyl benzamides as ligands for sigma receptors

5-Bromo-N-[4-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-butyl)]-2,3-dimethoxy-benzamide (1) is one of the most potent and selective sigma(2) receptor ligands reported to date. Previous structure-activity relationship studies of such tetrahydroisoquinolinyl benzamides have focused on the linker that connects the ring systems and the effects of benzamide ring substituents. The present study explores the effects of fusing methylene-, ethylene-, and propylenedioxy rings onto the tetrahydroisoquinoline in place of the two methoxy groups. These modifications decreased sigma(2) affinity by 8- to 12-fold, with no major differences noted with ring size. By contrast, the methylenedioxy analog showed a 10-fold greater sigma(1) affinity than 1, and progressively lower sigma(1) affinities were then noted with increasing ring size. We also opened the tetrahydroisoquinoline ring of 1 to study the effects of greater conformational fluidity on sigma receptor binding. The sigma(2) affinity of the open-ring compound decreased by 1700-fold, while sigma(1) affinity was not changed. Thus, a constrained tetrahydroisoquinoline ring system is key to the exceptional sigma(2) receptor binding affinity and selectivity of this active series.     

Altered expression of plant lysyl tRNA synthetase promotes tRNA misacylation and translational recoding of lysine

The Arabidopsis thaliana lysyl tRNA synthetase (AtKRS) structurally and functionally resembles the well-characterized prokaryotic class IIb KRS, including the propensity to aminoacylate tRNA(Lys) with suboptimal identity elements, as well as non-cognate tRNAs. Transient expression of AtKRS in carrot cells promotes aminoacylation of such tRNAs in vivo and translational recoding of lysine at nonsense codons. Stable expression of AtKRS in Zea mays causes translational recoding of lysine into zeins, significantly enriching the lysine content of grain.     

中国蛙类一新种(无尾目,蛙科)

描述了1种采自广西猫儿山国家级自然保护区的蛙类1新种,模式标本保存于沈阳师范大学自然博物馆.猫儿山林蛙,新种Rana maoershanensis sp.nov.(图1～17)正模:SYNU 06020120,雄性成体,李丕鹏和王绍能于2006年2月采集自广西壮族自治区猫儿山国家级自然保护区,海拔1 980 m.配模:SYNU 06020091,SYNU 06020122和SYNU06020124,雄性成体;SYNU06020121,SYNU06040153,SYN 0604154和SYNU 06040155,雌性成体.李丕鹏和王绍能于2006年2月和4月采集,采集地点与正模相同.蝌蚪:SYNU0602001和SYNU 0604001系列,采集信息与配模标本相同.新种具有如下主要鉴别特征:1)体略大;2)头宽略大于头长;3)背侧褶明显且略弯曲;4)胫跗关节前达眼角;5)雄性婚垫2团,无内声囊,腹部无雄性线;6)蝌蚪唇齿式多为Ⅰ:3-3/Ⅲ:1-1,少数为Ⅰ:3-3/Ⅳ.新种在头型上与中国林蛙相似,在体形上与昭觉林蛙相似.但与已知林蛙均有明显不同.新种的背侧褶略显弯曲,这一特点明显不同于主要分布于中国北方的黑龙江林蛙种组Rana amurensis group和中国林蛙种组R.chensinensis group的成员.新种与长肢林蛙种组R.longicrus group的镇海林蛙R.zhenhaiensis在背侧褶的弯曲特点上相似,但前者有别于后者的主要特点有:头型较宽扁,雌蛙后腿相对较长,蝌蚪唇齿式多为Ⅰ:3-3/Ⅲ:1-1.新种与长肢林蛙种组的其他林蛙不仅在背侧褶和头型等方面明显有别,而且蝌蚪唇齿式也显著不同.通过对四川、贵州和云南的昭觉林蛙R.chaochiaoensis成体和蝌蚪标本(包括地模标本)的核查和比较,新种的胫跗关节前达眼角,皮肤光滑,缺乏疣粒,雄性腹侧无雄性线,蝌蚪下唇乳突排列规则,中央无缺刻;而昭觉林蛙胫跗关节前达鼻孔或超过吻端,体侧和背部有圆疣或长疣,雄性背腹侧均有雄性线,蝌蚪下唇中央乳头排列稀疏或有缺刻.