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11.
12.
Long-term circulation of vaccine-derived poliovirus that causes paralytic disease 总被引:8,自引:0,他引:8 下载免费PDF全文
Cherkasova EA Korotkova EA Yakovenko ML Ivanova OE Eremeeva TP Chumakov KM Agol VI 《Journal of virology》2002,76(13):6791-6799
Successful implementation of the global poliomyelitis eradication program raises the problem of vaccination against poliomyelitis in the posteradication era. One of the options under consideration envisions completely stopping worldwide the use of the Sabin vaccine. This strategy is based on the assumption that the natural circulation of attenuated strains and their derivatives is strictly limited. Here, we report the characterization of a highly evolved derivative of the Sabin vaccine strain isolated in a case of paralytic poliomyelitis from a 7-month-old immunocompetent baby in an apparently adequately immunized population. Analysis of the genome of this isolate showed that it is a double (type 1-type 2-type 1) vaccine-derived recombinant. The number of mutations accumulated in both the type 1-derived and type 2-derived portions of the recombinant genome suggests that both had diverged from their vaccine predecessors approximately 2 years before the onset of the illness. This fact, along with other recent observations, points to the possibility of long-term circulation of Sabin vaccine strain derivatives associated with an increase in their neurovirulence. Comparison of genomic sequences of this and other evolved vaccine-derived isolates reveals some general features of natural poliovirus evolution. They include a very high preponderance and nonrandom distribution of synonymous substitutions, conservation of secondary structures of important cis-acting elements of the genome, and an apparently adaptive character of most of the amino acid mutations, with only a few of them occurring in the antigenic determinants. Another interesting feature is a frequent occurrence of tripartite intertypic recombinants with either type 1 or type 3 homotypic genomic ends. 相似文献
13.
Size-exclusion chromatography of enzymatically treated cellulose and related polysaccharides: a review 总被引:3,自引:0,他引:3
Eremeeva T 《Journal of biochemical and biophysical methods》2003,56(1-3):253-264
Size-exclusion chromatography (SEC) of wood pulp polysaccharides (cellulose and hemicelluloses) has become widely used for the analysis of these polymers, including monitoring of transformations occurring under various chemical and biological processes. The present review provides information on the different procedures and methodologies developed for the characterization of molecular mass distribution (MMD) and chemical composition of cellulose and hemicelluloses by SEC. This paper also includes the significant results obtained in the characterization of enzymatically treated wood polysaccharides. Conventional SEC with double detection (refractometric and UV), "hyphenated" with a fractional dissolution, was demonstrated to be an efficient method for simultaneous determination of MMD and chemical heterogeneity. 相似文献
14.
Rod and cone photoreceptors project from the outer retinal surface into a
carbohydrate-rich interphotoreceptor matrix (IPM). Unique IPM
glycoconjugates are distributed around rods and cones. Wheat germ
agglutinin (WGA) strongly decorates the rod matrix domains and weakly
decorates the cone matrix domains. This study characterizes the major
WGA-binding glycoprotein in the human IPM, which we refer to as SPACR
(sialoprotein associated with cones and rods). SPACR, which has a molecular
weight of 147 kDa, was isolated and purified from the IPM by lectin
affinity chromatography. A polyclonal antibody to SPACR was prepared that
colocalizes in tissue preparations with WGA-binding domains in the IPM.
Sequential digestion of SPACR with N- and O- glycosidases results in a
systematic increase in electrophorectic mobility, indicating the presence
of both N- and O-linked glycoconjugates. Complete deglycosylation results
in a reduction in the relative molecular mass of SPACR by about 30%.
Analysis of lectin binding allowed us to identify some of the structural
characteristics of SPACR glycoconjugates. Treatment with neuraminidase
exposes Galbeta1- 3GalNAc disaccharide as indicated by positive peanut
agglutinin (PNA) staining, accompanied by the loss of WGA staining. Maackia
amurensis agglutinins (MAA-1 and MAA-2), specific for sialic acid in
alpha2-3 linkage to Gal, bind SPACR, while Sambucus nigra agglutinin (SNA),
specific for alpha2-6 linked sialic acid, does not, indicating that the
dominant glycoconjugate determinant on SPACR is the O-linked carbohydrate,
NeuAcalpha2-3Galbeta1-3GalNAc. The abundance of sialic acid in SPACR
suggests that this glycoprotein may contribute substantially to the
polyanionic nature of the IPM. The carbohydrate chains present on SPACR
could also provide sites for extensive crosslinking and participate in the
formation of the ordered IPM lattice that surrounds the elongate
photoreceptors projecting from the outer retinal surface.
相似文献
15.
每搏量变异度是动态的容量监测指标.机械通气患者心肺的相互作用是每搏量变异度的产生基础,通过动脉压力波形分析技术可以进行连续监测.每搏量变异度能够准确预测容量治疗反应,与静态的血流动力学参数相比,对于优化心输出量和组织氧供更有优势,但也存在一定的局限性.每搏量变异度受多种因素影响且不能用于自主呼吸和心律失常的患者.临床应用时应该综合考虑其影响因素,结合其他的指标和方法指导容量治疗. 相似文献
16.
Ivanova OE Eremeeva TP Leshchinskaia EV Korotkova EA Iakovenko ML Cherniavskaia OP Cherkasova EA Dragunskaia EM Dekonenko EP Martynenko IN Krasnoproshina LI Sorokina MP 《Zhurnal mikrobiologii, epidemiologii, i immunobiologii》2007,(5):37-44
From 1998 through 2005 3,294 cases of acute flaccid paralysis (AFP) including 93 cases with clinical picture of poliomyelitis were registered in Russian Federation. From the latter cases 91 were classified as vaccine-associated paralytic poliomyelitis (VAPP): 66 were VAPP cases in oral poliomyelitis vaccine (OPV) recipients and 25--VAPP cases in contacts. VAPP rate was 1 case per 1.6 million of distributed OPV doses, 1 case per 2.2 million doses for OPV recipients, and 1 case per 186,000 doses for recipients of 1st OPV dose in children aged < 1 year. Majority of VAPP cases in recipients occurred after 1st dose (89.4%) and in contacts--in non-vaccinated children (76%). Mean interval between OPV administration and onset of VAPP in recipients was 21 days. Children aged < 1 year were predominant among VAPP cases (92.4% among recipient VAPP cases, and 80% among contact VAPP cases). Majority of the patients had unfavorable health status including defects of immunity. Most of poliovirus strains isolated from VAPP cases belonged to type 3 (52.9%) whereas to type 2 and 1--29.8% and 17.4% of strains respectively. All VAPP cases were associated with vaccine-derived polioviruses. A highly diverged poliovirus type 1 (2.65% of nucleotide substitutions in VP1 region) was isolated from patient with contact VAPP. Formation of poliovirus-neutralizing serum antibodies in children with VAPP including persons with immunodeficiency reflects the ability of the organism to produce specific antiviral immune response. 相似文献
17.
白马雪山国家级自然保护区典型森林生态系统服务 总被引:1,自引:0,他引:1
生态系统服务是近年来生态学研究的热点领域,对关键区域生态系统服务的研究具有重要意义.云南省白马雪山国家级自然保护区地处青藏高原南延部分,拥有独特的地理位置,是生物多样性保护的热点区域.本文对该保护区森林生态系统的生物量与生产力、水源涵养、营养物质循环等3项服务的功能量进行了评估.结果表明:保护区森林总生物量2215.86×104t,生产力171.84×104t·a-1;水源涵养量11964.56×104m3;N、P、K年吸收量分别为26025.94t、2638.57t、12016.85 t.研究表明,保护区森林生态效益显著,对于维持当地以及周边地区的生态安全具有重要意义. 相似文献
18.
Yong?Zhu Pierre-Edouard?Fournier Marina?Eremeeva Didier?RaoultEmail author 《BMC microbiology》2005,5(1):11
Background
Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, include Indian tick typhus rickettsia (ITTR), Israeli spotted fever rickettsia (ISFR), and Astrakhan fever rickettsia (AFR). Although closely related genotypically, they are distinct serotypically. Using multilocus sequence typing (MLST), we have recently found that distinct serotypes may not always represent distinct species within the Rickettsia genus. We investigated the possibility of classifying rickettsiae closely related to R. conorii as R. conorii subspecies as proposed by the ad hoc committee on reconciliation of approaches to bacterial systematics. For this, we first estimated their genotypic variability by using MLST including the sequencing of 5 genes, of 31 rickettsial isolates closely related to R. conorii strain Malish, 1 ITTR isolate, 2 isolates and 3 tick amplicons of AFR, and 2 ISFR isolates. Then, we selected a representative of each MLST genotype and used multi-spacer typing (MST) and mouse serotyping to estimate their degree of taxonomic relatedness. 相似文献19.
20.
Cicada acoustic communication: potential sound partitioning in a multispecies community from Mexico (Hemiptera: Cicadomorpha: Cicadidae) 总被引:1,自引:0,他引:1
JÉRÔME SUEUR 《Biological journal of the Linnean Society. Linnean Society of London》2002,75(3):379-394
Multispecies cicada communities in neotropical rainforests produce a complex and intense acoustic environment. In a fragment of a Mexican rainforest (Veracruz, Mexico), a cicada community at the end of the dry season consisted of nine species ( Daza montezuma; Pacarina schumanni; Miranha imbellis; Dorisiana sutori; Fidicinoides picea; Fidicinoides pronoe; Quesada gigas; one species of the genus Neocicada and one uncaught canopy species). Seven of the nine species formed dense choruses at dawn and at dusk. Each species showed preferences in the height of calling sites. Males of the species were solitary or gregarious, and followed a 'call-fly' or a 'call-stay' calling strategy. Acoustic signals of each species had particular time and frequency patterns. All these specific features appear to separate the nine species acoustically and lead to a partitioning of the acoustic environment. The acoustic partitioning might decrease the risk of heterospecific courting and mating.© 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 379–394. 相似文献