共查询到19条相似文献,搜索用时 109 毫秒
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近年全球受各种流感病毒威胁,包括H7N9及H5N1禽流感等。香港大学医学院与美国国家卫生研究院在天花疫苗中.加入流感病毒基因,成功研发新型甲型流感疫苗.可对抗禽流感病毒H7N9及H5N1、季节性流感H3N2及H1N1,及高致病性H7N7。一旦爆发大型流感,可于短时间内大规模生产疫苗。 相似文献
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A(H1N1)流感病毒是2009年3~4月在美国和墨西哥发现的一种流感病毒变异的新病毒株.这类流感疫情的蔓延引起了世界各国和世界卫生组织的严重关注.本文介绍了A(H1N1)流感新病毒株及感染这种病毒患者的症状,A(H1N1)流感病毒的致命力和传播,流感病毒变异对抗病毒药的抗药性,以及1918年流感大流行病毒聚合酶特性,人流感病毒和禽流感病毒聚合酶的结晶结构及其在感染中的作用.据此,提出了抗流感病毒药的筛选思路和研究方向,为抗流感病毒新药的设计和开发提供有益的参考. 相似文献
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A(H1N1)流感病毒及抗病毒新药的筛选 总被引:1,自引:0,他引:1
A(H1N1)流感病毒是2009年3~4月在美国和墨西哥发现的一种流感病毒变异的新病毒株.这类流感疫情的蔓延引起了世界各国和世界卫生组织的严重关注.本文介绍了A(H1N1)流感新病毒株及感染这种病毒患者的症状,A(H1N1)流感病毒的致命力和传播,流感病毒变异对抗病毒药的抗药性,以及1918年流感大流行病毒聚合酶特性,人流感病毒和禽流感病毒聚合酶的结晶结构及其在感染中的作用.据此,提出了抗流感病毒药的筛选思路和研究方向,为抗流感病毒新药的设计和开发提供有益的参考. 相似文献
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A(H1N1)流感病毒及抗病毒新药的筛选 总被引:1,自引:1,他引:1
A(H1N1)流感病毒是2009年3~4月在美国和墨西哥发现的一种流感病毒变异的新病毒株。这类流感疫情的蔓延引起了世界各国和世界卫生组织的严重关注。本文介绍了A(H1N1)流感新病毒株及感染这种病毒患者的症状,A(H1N1)流感病毒的致命力和传播,流感病毒变异对抗病毒药的抗药性,以及1918年流感大流行病毒聚合酶特性,人流感病毒和禽流感病毒聚合酶的结晶结构及其在感染中的作用。据此,提出了抗流感病毒药的筛选思路和研究方向,为抗流感病毒新药的设计和开发提供有益的参考。 相似文献
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为了从本质上揭示H1N1病毒分子的变异、流感流行等关系,提出一种构建H1N1型流感病毒进化树的新方法。在1902—2013年全球22 455条H1N1型流感病毒HA蛋白序列和16444条NA蛋白序列数据的基础上,利用其特征向量构建基于内积的蛋白序列相似度;采用基于相似度的完全聚类图的方法进行数据系统粗粒化的相似信息提取;最后,利用基于模糊邻近关系的结构聚类方法构建H1N1型禽流感病毒HA、NA蛋白序列的进化树及算法研究。试验结果表明:H1N1病毒的变异不仅与爆发时间密切相关,还与所分布地域及地域间的距离有很大关系,且分布地域间的距离越近,爆发的病毒进化的相似程度越高。因此这种基于大数据处理的新方法能有效揭示流感病毒的进化关系,为进一步研究流感病毒的变异、进化与预测奠定了基础。 相似文献
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1918年的流感大流行虽已过去90多年,但现仍不时地滋扰着人类.甲型H3N2流感病毒是流行循环中季节性流感最主要的类型[1].2009年3~4月美国和墨西哥发现了流感病毒变异的新型流感,世界卫生组织(WHO)定名为甲型H1N1流感[2],6月中旬WHO将流感警戒从5级升至最高级6级,宣布甲型H1N1流感大流行.入冬以来,全球甲型H1N1流感暴发第2波,防控流感形势严峻. 相似文献
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采用热重-差热法对1-L-亮氨酸-1-脱氧-D-果糖(Ⅰ)和1-L-异亮氨酸-1-脱氧-D-果糖(Ⅱ)的热失重和热裂解温度进行了研究,通过在线裂解GC-MS联用技术分别对(Ⅰ)和(Ⅱ)在350℃、450℃、550℃、650℃、750℃和850℃条件下的裂解产物进行了鉴定。研究结果表明2种Amadori化合物的的热失重曲线相似,(Ⅰ)的裂解温度为144.67℃,(Ⅱ)的裂解温度为164.26℃,600℃时(Ⅰ)和(Ⅱ)失重约80%;二者裂解产物主要为吡嗪类、吡啶类、吡咯类、喹啉类和呋喃类等杂环化合物,芳香族化合物以及醛类和酮类,其中以吡嗪类为主;裂解产物的数量随着裂解温度的升高而增多,(Ⅰ)的裂解产物数量与(Ⅱ)的裂解产物数量相当。对(Ⅰ)和(Ⅱ)的主要裂解产物形成途径进行了初步探讨,可为研究其在卷烟燃烧过程中的转化行为提供参考。 相似文献
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Mikstacka R Baer-Dubowska W Wieczorek M Sobiak S 《Molecular nutrition & food research》2008,52(Z1):S77-S83
Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural stilbene derivative occurring in grapes, peanuts and red wine. Its chemopreventive action has been established in studies on animal models. Recently, numerous classes of compounds with stilbene backbone have been investigated for their biological activity concerning cancer prevention; e. g. resveratrol methyl ethers appeared to be specific and potent inhibitors of cytochromes P450 (CYP) family 1 involved in the activation of procarcinogens. Since the replacement of the 4'-hydroxyl with a thiomethyl group is supposed to reduce toxicity of stilbene derivatives, the purpose of this study was the synthesis and evaluation of a series of 4-thiomethyl-trans-stilbene derivatives differing in a number and position of additional methoxy groups. Their inhibitory potency toward human recombinant CYPs: CYP1A1, CYP1A2 and CYP1B1 have been studied and compared with the effect of resveratrol and its analogues. Among compounds tested, 2-methoxy-4'-thiomethyl-trans-stilbene and 3-methoxy-4'-thiomethyl-trans-stilbene demonstrated the most potent and selective inhibitory effect on CYP1A1 and CYP1B1 activities. The results of our study indicate that modification of stilbene derivatives with thiomethyl group may influence the selectivity and inhibitory potency of these compounds toward P450 isozymes. Thus, it should be considered in developing new chemopreventive agents based on their mechanism of action. 相似文献
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采用热重-微分热重技术研究了1-L-谷氨酸-1-脱氧-D-果糖的热失重和裂解温度,通过在线热裂解与气质联用技术分别分析研究了无氧和有氧条件下1-L-谷氨酸-1-脱氧-D-果糖在300℃、600℃、750℃和900℃四个温度的热裂解产物。研究结果表明1-L-谷氨酸-1-脱氧-D-果糖的裂解温度为161.3℃,在700℃时失重达到90.50%。无氧和有氧条件下裂解产物的种类和数量随着裂解温度升高而增多,有氧条件下裂解产物总数稍多于无氧条件,但品种有明显差异。 无氧裂解和有氧裂解产物主要为酮类、吡咯类、吡啶类、呋喃类、吡嗪类、吲哚类以及少量芳香族化合物。有氧热裂解产物的香韵分析结果表明1-L-谷氨酸-1-脱氧-D-果糖裂解产物具有烘烤香、坚果香、甜香、花香、奶香等香韵。 相似文献
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采用热重/差热(TG-DTA)和在线裂解气相色谱/质谱联用(Py-GC/MS)分析技术对1-L-丙氨酸-1-脱氧-D-果糖(Ala-Fru)的热裂解进行了研究.TG-DTA分析结果显示,Ala-Fru的初始裂解温度为147.47℃,600℃时样品质量损失至原重的25%;在350℃,450℃,550℃,650℃,750℃和850℃这6个温度下的Py-GC/MS结果显示,裂解产物的种类和数量随裂解温度的升高而增多,其裂解产物主要为吡嗪类、吡啶类、吡咯类和呋喃类等杂环类化合物以及少量酮类化合物,这些物质是卷烟烟气中重要的香味成分. 相似文献
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为探索以D-甘露糖与氨基酸的美拉德反应制备Amadori化合物的可行性问题,以D-甘露糖和L-色氨酸为原料合成了1-L-色氨酸-1-脱氧-D-果糖,利用IR、NMR和HR-MS对产物进行了结构表征,采用单因素试验和正交试验优化了合成工艺,利用在线裂解气相色谱/质谱联用(Py-GC/MS)法研究了产物的热裂解行为。结果表明:①最佳合成条件为:当L-色氨酸投料量为30 mmol时,反应温度65℃、反应时间6.0 h、物料比1:1(D-甘露糖与L-色氨酸的物质的量比)、催化剂用量0.5 mmol及溶剂用量80 mL,此条件下产率达到45.2%;②无论有氧或无氧条件下裂解,产物种类均随温度升高而增加,有氧条件裂解产物种类多于无氧条件;在600℃有氧条件下,1-L-色氨酸-1-脱氧-D-果糖裂解生成具有花香、烘烤香、坚果香、焦糖香等香韵的产物;③以D-甘露糖和L-色氨酸为原料合成1-L-色氨酸-1-脱氧-D-果糖的技术方法可行,产品收率较高。 相似文献
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Mirko H. Brummer Katja J. Kivinen Jussi Jntti Jaana Toikkanen Hans Sderlund Sirkka Kernen 《Yeast (Chichester, England)》2001,18(16):1525-1536
Sec1 proteins are implicated in positive and negative regulation of SNARE complex formation. To better understand the function of Sec1 proteins we have identified the nature of the temperature-sensitive mutations in sec1-1 and sec1-11. The sec1-1 mutation changes a conserved glycine(443) to glutamic acid. The sec1-11 mutation changes a highly conserved arginine(432) to proline. Based on homology and the crystal structure of the mammalian nSec1p, the corresponding amino acids localize to the 3b domain of nSec1p. Compared to the wild-type Sec1p the mutant proteins are less abundant even at the permissive temperature. Thus, the R432P and G443E mutations may cause structural alterations that affect folding and make the mutant proteins more susceptible to degradation. The remaining part is sufficient for growth and protein secretion at 24 degrees C and thus is likely to be properly folded. At 37 degrees C the mutant proteins become non-functional. In pulse-chase-type experiments the newly synthesized Sec1-1 and Sec1-11 proteins decayed similarly with the wild-type protein. Thus, the non-functionality of the mutant proteins cannot be explained by denaturation-induced degradation only. It is possible that the newly synthesized mutant proteins fold slowly and are susceptible to degradation before they have managed to fold and associate with other proteins. The mutant proteins were unable to interact with the Sec1p-interacting proteins Mso1p and Sso2p in the two-hybrid assay, even at the permissive temperature. These results localize sec1-1 and sec1-11 mutations to a domain of Sec1p and suggest a mechanism by which sec1-1 and sec1-11 cells become temperature-sensitive. 相似文献
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M.A. Bollen H.J. Wichers J.P.F.G. Helsper H.F.J. Savelkoul M.A.J.S. van Boekel 《Food chemistry》2010,119(1):2518
Natural and recombinant Bet v 1, the major birch pollen allergen, and homologous allergens, Api g 1 and Dau c 1, from celery and carrot, respectively, were studied by CD spectroscopy under conditions of varying denaturant concentration, pH and temperature to determine fundamental thermodynamic parameters for conformational stability. Thermodynamic studies increase basic knowledge regarding differences between birch pollen-related allergens and are of importance in choosing processing conditions. The conformational stability determined from guanidine hydrochloride denaturation curves was similar for rBet v 1.0101 and rApi g 1.0101. Conformational responses to chaotropic salt were different for recombinant allergens from different species, but were similar for the natural isoform mixtures. The conformational stabilities of nApi g 1 and nDau c 1, were shown to be similar to rBet v 1.2801 at pH > 4.4 [Mogensen, J. E., Ipsen, H., Holm, J., & Otzen, D. E. (2004). Elimination of a misfolded folding intermediate by a single point mutation. Biochemistry, 43(12), 3357-3367], but nApi g and nDau c 1 were stable to heating at lower pH-values. 相似文献