首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
广东地区人禽流感H5N1毒株的核蛋白基因变异和进化   总被引:4,自引:1,他引:3  
目的通过对人禽流感H5N1毒株核蛋白(NP)基因序列的变异分析,揭示毒株NP基因变异与进化。方法检测广东地区人禽流感H5N1毒株NP基因核苷酸序列,同时检索全球人禽流感H5N1毒株NP基因序列,采用DNAStar5.0软件对检索的人禽流感H5N1毒株NP基因核苷酸序列进行比对和分析;并结合流行病学资料对变异毒株进行进化速度分析。结果1997--2006年45株毒株胛基因核苷酸序列同源性分成3类,1997--1998年毒株为第1类,2004--2005年毒株为第2类,2003年毒株和2006年毒株为第3类;NP基因35个氨基酸位点全部置换,占7.03%(35/498);2003—2006年H5N1毒株通过氨基酸第430位(1〈430T)位点的置换,增加一个糖基化位点(NGT430-432;GD—01—06毒株第370位发生N3加S变异;增加一个糖基化位点(NES368.370)。同义变异中,NP基因Ks(同义变异速度)值为2.03×10^-5~2.55×10^-5核苷酸/d,Ka(错义变异速度)值为1.58×10^-6~3.10×10^-6核苷酸/d,检验发现进化无明显选择性压力存在。结论1997--1998年毒株、2004--2005年毒株、2003年毒株和2006年毒株NP基因核苷酸有差异;2003--2006年人禽流感H5N1毒株NP基因增加一个糖蛋白位点、GD-01—06毒株再增加一个糖蛋白位点可能改变毒株抗原性。人禽流感H5N1毒株在自然界变异频繁,随着其自然进化,H5N1毒株具有人.人传播能力的概率较大。  相似文献   

2.
目的 预测并筛选人禽流感H5N1毒株核蛋白(NP)的B细胞抗原表位.方法 采用DNAStar Lasergene 7.1软件,进行人禽流感H5N1毒株NP基因核苷酸序列分析.采用Kyte-Doolittle的亲水性方法、Emini方法和Jameson-Wolf抗原指数方法,辅以对NP的二级结构中的柔性区域的分析,采用SPSS13.0进行聚类、相关和四分位数分析,建立一种统计学筛选程序,预测H5N1病毒NP的B细胞表位,并对毒株A/GD/01/06(H5N1)的NP变异进行评价.结果 预测并筛选最有可能的B细胞表位为位于NP的N端317~326、452~457、467~473、367~370、491~498、375~378、171~177、48~53、245~250、76~104肽段等.A/GD/01/06(H5N1)的NP通过氨基酸第370位(N370S)位点置换,增加一个糖基化位点(NES368-370)并改变NP的特性.结论 用多参数预测并统计学筛选H5N1毒株NP的B细胞表位,可以为分子免疫学研究和药物筛选提供依据.A/GD/01/06(H5N1)毒株NP氨基酸第370位(N370S)位点置换改变其抗原性,但抗原表位大小未变(SNEN367-370).  相似文献   

3.
目的 了解2009-2011年广东甲型H1N1流感病毒血凝素基因的HA1进化特征。方法 选取广东甲型H1N1流感病毒83株,提取病毒RNA,经RT-PCR反应扩增HA1并测序,测定的序列用生物信息软件分析,与GenBank中相关序列比较,并对推导的编码氨基酸序列进行进化分析。结果 2009-2011年广东甲型H1N1流感病毒HA1基因的进化速率是5.2× 10-3,高于人季节性H1N1病毒;变异氨基酸多数位于HA蛋白表面,其中部分位于抗原决定簇;在两例死亡病例分离株HA1的第222位氨基酸发生D222G/D222N变异。结论 遗传进化分析表明,甲型H1N1流感病毒发生了一定程度的变异,造成2011年初在广东的再次流行。HA1的第222位氨基酸变异可能与疾病的严重程度有关。  相似文献   

4.
目的 研究1995-2007年深圳市流行的H1N1流感病毒血凝素(HA)的基因特性.方法 选取在该期间分离培养到的64株H1N1流感病毒,对其进行HA片段核苷酸序列测定并推导出其氨基酸序列,用Simmonic软件和Mega软件对其进行分析.结果 深圳市H1N1流感毒株在进化树上可以划分为A、B、C三个分枝.部分2005-2006年毒株与2001年毒株在同一分枝上.通过同源性分析发现部分WHO所推荐的疫苗株在时间上滞后于深圳株.深圳H1N1株的4个抗原决定簇及受体结合位点均发生了氨基酸的替换.除1995年外其余年份的毒株均在137位上发生了氨基酸的缺失.结论 1995-2007年深圳市H1N1毒株氨基酸的变异主要集中在抗原决定簇及受体结合部位.并且抗原决定簇的变异活跃区域随时间的推移发生了转移.  相似文献   

5.
目的观察从死禽体内分离的禽流感H5N1病毒株对小鼠的致病情况,筛选一株可用于小鼠攻毒实验的H5N1毒株。方法将17株禽源H5N1病毒分别滴鼻感染6~8周龄Balb/c小鼠,观察其对小鼠的致病和致死情况。通过测定其中毒力较强一株的EID_(50)、TCID_(50)、小鼠LD_(50)及濒死小鼠不同组织中病毒载量,判定其致病力;采用遗传进化分析绘制HA基因进化树,了解其进化特征。结果动物实验表明,17株高致病性禽源H5N1毒株中,仅有一株对小鼠为高致病性。该毒株TCID_(50)/100μl=7.2,EID_(50)/100μl=8.325,小鼠1 LD_(50)/100μl=6.318≈10~2EID_(50)。鼻粘膜感染4~6 d小鼠发病,表现为精神萎靡、食欲减退、竖毛、弓背等临床症状,体重明显减轻。小鼠死亡集中在发病后的2~5 d,耐过死亡者12 d完全恢复正常。从濒死感染小鼠脾、肺、鼻及脑组织中皆可检出流感病毒NS片段,病毒数载量以脑组织中最多,达3.56×10~(10)拷贝/5μl。结论筛选到一株对小鼠呈强致病性H5N1亚型禽流感毒株,可以用于禽流感疫苗交叉保护效果评价的小鼠攻击实验,也可以作为感染模...  相似文献   

6.
我国猪群中H9N2亚型毒株HA和NA基因特性的研究   总被引:3,自引:2,他引:3  
目的 了解我国内地从猪中分离到H9N2亚型毒株HA和NA基因来源及它们使猪致病的原因。方法 用PCR扩增目的基因,与P^GEM-T Easy Vector4℃过夜连接,重组质粒转化DH-10β细菌,筛选阳性菌落,酶切鉴定,测序。然后,进行进化树分析。结果 两株猪H9N2毒株HA蛋白分子上第226位上氨基酸为L,这与从人和猪所分离出的H9N2毒株相同,其连接肽属对禽致病的毒株,但它们的序列为R-L-S-R,而不是R-S-S-R;其NA蛋白茎区第62~64位存在掉失,这与A/Shaoguarn/408/98,A/Swine/Hong Kong/9/98及A/Duck/Hong Kong/y280/97(H9N2)毒株相同;HA与NA基因进化树分析表明,两株猪H9N2毒株的HA基因接近于A/Chicken/Hong Kong/G23/97和A/Chicken/Hong Kong/G9/97.而NA基因接近于A/Shaoguan/408/98毒株。结论 两株猪H9N2亚型毒株的HA和NA基因可能性最大来自禽H9N2毒株。由于其HA蛋白分子上连接肽氨基酸序列发生替换,可能造成了它们对猪具有致病性。禽H9N2毒株NA蛋白茎区氨基酸掉失,造成了它们能直接感染猪。  相似文献   

7.
目的 了解我国2004-2008年A(H1N1、H3N2)型流感病毒流行情况、抗原性和基因特性变异关系,了解疫苗株与我国流行株之间抗原性变化情况.方法 选择2004年以来我国分离的A(H1N1、H3N2)型流感病毒进行抗原性及HA1区基因序列,通过比对HA1蛋白位点变异情况,分析我国流感病毒抗原性及基因特性变化情况.结果 A(H1N1)亚型流感毒株抗原性2004-2007年分离的A(H1N1)亚型流感病毒的抗原性与疫苗株A/New Caledonia/20/1999(H1N1)类似;2008年我国流行的A(H1N1)亚型毒株的抗原性与2008-2009年北半球的流感疫苗株A/Brisben/59/2007(H1N1)类似.2004-2005年分离的A(H3N2)亚型流感病毒的抗原性与疫苗株A/Fujian/411/12002(H3N2)比较发生了变异;2006-2007年我国流行的H3N2毒株与A/Wiscansin/67/2006(H3N2)类似,2008年我国流行的H3N2毒株与疫苗株A/Brisben/10/2006(H3N2)类似.结论 2004-2008年我国流行的A(H1N1、H3N2)亚型流感病毒的抗原性和基因特性发生了改变.  相似文献   

8.
目的 研究高致病性禽流感(HPAI)H5N1病毒NS1蛋白对干扰素诱导蛋白10(IP-10)的影响.方法 分别将禽流感病毒A/Anhui/1/2005(H5N1)的NS1基因、插入80-84位缺失氨基酸的NS1突变基因及流感病毒A/Puerto Rico/8/1934(H1N1)的NS1基因克隆至真核表达载体pEGFP-N1,转染人支气管上皮细胞BEAS-2B,流式细胞仪检测转染细胞内IP-10的表达情况.结果 与pEGFP-N1对照组相比,三种NS1蛋白均能下调BEAS-2B细胞IP-10的表达(P<0.01),但三者之间下调程度差异无统计学意义(P>0.01).结论 A/Anhui/1/2005(H5N1)禽流感病毒单一NS1蛋白能够抑制BEAS-2B细胞IP-10表达,但这并不能完全阐明其与病毒致病性之间的关系.  相似文献   

9.
猪型(H1N1)流感病毒血凝素和神经氨酸酶基因来源的研究   总被引:1,自引:2,他引:1  
目的 研究2002年我国内地从猪群中分离的猪型(H1N1)毒株HA和NA基因来源。及其使猪致病的原因。方法 用PCR扩增目的基因,用P^GEM-T Easy Vector,4℃过夜连接,重组质粒转入DH-10B细菌,筛选阳性菌落,酶切鉴定,送六合通公司自动测序,并作进化树分析。结果 3株猪型(H1N1)病毒的HA和NA基因属猪型(H1N1)流感病毒,而不同于其他禽或人的H1N1亚型流感病毒。2002年猪型毒株由1991年猪型毒株演变而来。近来我国内地猪群中猪型毒株活动增强,其对猪能致病是由于病毒粒HA和NA蛋白抗原性发生变异所造成。结论 3株猪型病毒的HA和NA基因来源于猪型(H1N1)毒株。近来猪型毒株对猪具有致病性和活动增强是由于其HA和NA蛋白分子上氨基酸序列发生替换所造成。  相似文献   

10.
目的比较2010年广州市分离到的甲型H1N1流感病毒血凝素(HA)基因和2009年中国大陆甲型H1N1流感病毒HA基因的变异情况,为甲型H1N1流感的监测和防控提供理论依据。方法收集2010年广州市有发热和呼吸道症状病人的咽拭子标本,用H1N1流感特异性引物进行PCR检测,扩增分离到的H1N1病毒HA片段,测序后与2009年的H1N1毒株进行比对和分析,并用生物信息学方法对抗原位点和糖基化位点进行分析。结果共收集到426份标本,甲型流感阳性211份,其中H1N1流感4株,与2009年分离的甲型H1N1流感相比,有12个氨基酸碱基位点发生了有意义突变,其中6个位点位于抗原位点上;4株毒株HA基因145位氨基酸都发生了变异;其中2株毒株在第180位氨基酸位点的抗原位点发生了变异。进化分析表明4株毒株与2009年中国大陆分离的8株毒株进化关系较远。结论 2010年广州市甲型H1N1毒株与2009年相比发生了较大变异。HA基因145位和180位氨基酸位点变异对H1N1毒株抗原变异有重要意义。本文分离的A/Guangdong/ZS03/2010(H1N1)和A/Guangdong/ZS01/2010(H1N1)毒株可能已经发生了抗原性漂移。  相似文献   

11.
Renal dysplasia and asplenia in two sibs   总被引:2,自引:0,他引:2  
A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.  相似文献   

12.
Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc2 (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.  相似文献   

13.
About 1900, modern food selection and processing caused widespread epidemics of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a panhypovitaminosis B, i.e., a mixture of substrate beriberi and substrate pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse endemic disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for primates. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.  相似文献   

14.
15.
There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.  相似文献   

16.
Newton H 《Medical history》2011,55(2):153-182
Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.  相似文献   

17.
Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.  相似文献   

18.
The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.  相似文献   

19.
HLA-A,-B,-C,-DRB1 and -DQB1 alleles have been studied in Chimila Amerindians from Sabana de San Angel (North Colombian Coast) by using high resolution molecular typing. A frequent extended haplotype was found:HLA-A*24:02-B*51:10-C*15:02-BRB1*04:07-DQB1*03:02 (28.7%) which has also been described in Amerinndian Mayos Mexican population (Mexico, California Gulf, Pacific Ocean). Other haplotypes had already been found in Amerindians from Mexico (Pacific and Atlantic Coast), Peru (highlands and Amazon Basin), Bolivia and North USA. A geographic pattern according to HLA allele or haplotype frequencies is lacking in Amerindians, as already known. Also, five new extended haplotypes were found in Chimila Amerindians. Their HLA-A*24:02 high frequencies characteristic is shared with aboriginal populations of Taiwan; also, HLA-C*01:02 high frequencies are found in New Zealand Maoris, New Caledonians and Kimberly Aborigines from Australia. Finally, this study may show a model of evolutionary factors acting and rising one HLA allele frequency (-A*24:02), but not in others that belong to the same or different HLA loci.  相似文献   

20.
Starting with the integument, we see many organs are contractile sacs or multiples thereof, which tubes or bags constitute the major part of the entire body. Recognition of this basic unit and its characteristics sheds new light, individually and collectively, on many disorders previously considered unrelated. Muscular tears and perforations develop in the walls of these chambers, being no way peculiar to those organs, wherein, hydrochloric acid occurs. So, it is not necessary to explain the absence of excessive acid from patients who exhibit holes in the gastric, uterine, aortic, duodenal, rectal, pulmonary, retina, and other walls. Muscle, not acid is the great common factor relating idiopathic disorders in the gastrointestinal tract to each other and to similar diseases in other systems. When the units are linked together, the lesions tend to appear as arthropathies, i.e. at the joints. Rephrasing common-place observations, frees us from conventional, conceptual cul-de-sacs. An observation is only as good as its interpretation, so all possibilities must be considered, otherwise, we will remain blinded by our misconceptions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号