摘要： The crystal structure of the Sabin strain of type 3 poliovirus (P3/Sabin) complexed with the antiviral drug WIN51711 has been determined at 2.9 Angstrom resolution. Drugs of this kind are known to inhibit the uncoating of the virus during infection, by stabilizing the capsid against receptor-induced conformational changes. The electron density for the bound drug is very well defined so that its position and orientation are unambiguous. The drug binds in a nearly extended conformation, slightly bent in the middle, in a blind pocket formed predominantly by hydrophobic residues in the core of the beta-barrel of capsid protein VP1. Comparisons between this structure, the corresponding drug complex in human rhinovirus 14 (HRV14), and the native structures of both viruses demonstrate that the binding of WIN51711 has markedly different effects on the structures of these two viruses. Unlike HRV14, wherein large conformational changes are observed in the coat protein after drug binding, the binding of this drug in poliovirus does not induce any significant conformational changes in the structure of the capsid protein, though the drug has a greater inhibitory effect in P3/Sabin than in HRV14. The implications of this result for the mechanism of capsid stabilization are discussed.

关键词： 毁害   小儿麻痹症   糖丸   脊髓灰质炎疫苗   残疾人   儿童   当代医学   群体免疫屏障   中年人   无脊髓灰质炎  

摘要： 一位中年人因儿时患过脊髓灰质炎(俗称小儿麻痹)而导致肢体残疾,正是这种病,毁掉了他一生的快乐和幸福。学上不成,工作找不到,媳妇就更娶不上了,还要忍受着精神上的巨大痛苦。至今,他的母亲一提到此,仍禁不住泪水涟涟。 据统计,目前全国有5000多万残疾人,而大约每20个残疾人中就有一个人是由于患脊髓灰质炎而致残的,可以说,小儿麻痹症是儿童的灾难！

关键词： Membrane Proteins   Animals   Base Sequence   Cell Line   DNA Primers   Genome   Viral   Humans   Kidney   Macaca fascicularis   Mice   Mice   Transgenic   Molecular Sequence Data   Mutagenesis   Poliovirus Vaccine   Oral   Polioviruses   Polymerase Chain Reaction   RNA   Viral   Receptors   Virus   Temperature   Virulence  

摘要： We have studied methods for testing the neurovirulence of live poliovaccine viruses by intraspinal inoculation into mice carrying the human poliovirus receptor gene CTS mice). A comparison of the neurovirulence of Sabin type 3 vaccine virus and related viruses using the 50% paralysis dose determined after intraspinal inoculation into the Tg mice as an index revealed a close correlation between the results of the paralysis dose in Tg mice, the neurovirulence expressed by the histopathological lesion score in monkeys, and the temperature sensitivity of the viruses. The results of experiments in the Tg mice also showed a good correlation with the humber of mutations at position 472 from U to C in the 5' noncoding region in the genomes of the viruses tested. These results strongly suggest that the neurovirulence test for oral poliomyelitis vaccine using the Tg mice is an excellent method and may be used in place of the test using monkeys. (C) 1995 Academic Press, Inc.

关键词： POLIOVIRUS   MEMBRANE PERMEABILITY   PORE-FORMING PROTEIN  

摘要： Poliovirus protein 3AB contains a predicted amphipathic helix that could lead to pore formation in membranes. We have introduced various mutations in the hydrophobic domain of the protein and the membrane-modifying properties of the resulting mutants have been analyzed. Expression of wild type 3AB protein in E. coli increases the influx and efflux of different molecules such as nucleosides, lactose analogues and antibiotics. Thus, 3AB expression makes E. coli cells two orders of magnitude more sensitive to hygromycin B, a non-permeant inhibitor of translation, and causes a 15-20-fold enhancement in the efflux of uridine. Changes in membrane permeability take place under conditions where no cellular lysis is detected and when other molecules such as beta-galactosidase or polyribonucleotides are kept inside the cell. These membrane modifications can be blocked to different extents by amino acid substitutions in the membrane-spanning region of the protein. These results suggest that poliovirus protein 3AB could possess an intrinsic ability to form pores in natural membranes, thus allowing the flux of small hydrophylic molecules through them.

关键词： Genome   Viral   Polioviruses   RNA   Viral   Viral Core Proteins   Amino Acids  

摘要： The poliovirus polypeptide 3AB, the precursor of the genome-bound VPg protein, stimulates in vitro the synthesis of poly(U) directed by the viral polymerase 3D(pol) (Lama, J., Paul, A., Harris, K., and Wimmer, E. (1994) J. Biol. Chem. 269, 66-70), suggesting that 3AB could be modulating the activity of the viral polymerase in poliovirus-infected cells. To address the exact function of 3AB in the viral replication cycle, a biochemical and molecular genetic analysis of 3AB has been carried out, 3AB protein bound RNA probes in two different assays, and amino acid positions implicated in the RNA binding activity of 3AB were determined, Mutant proteins with reduced RNA binding activity were unable to stimulate 3D(pol) polymerase activity. Purified protein 3A showed no RNA binding or 3D(pol) stimulatory activity, but 3A and VPg mutations conferred a synergistic effect on the 3AB functions. Polioviruses encoding for these mutant SABs were constructed. These mutant viruses translated their RNA genomes in vitro and processed their polyproteins as wild type virus did. Cells infected with 3AB mutant viruses showed over 90% inhibition in the accumulation of plus and minus viral RNA strands and more than 100-fold reduction of virus yield at 4 h postinfection. Our results suggest that 3AB protein functions in vivo as a co-factor of the viral polymerase and that the activity of 3AB maybe regulated by proteoIytic processing.

关键词： 强化免疫   潘集区   脊髓灰质   炎疫苗   接种率调查   1996年   防保人员   连续强化   安徽淮南   汇总表  

摘要： 我区1993年开始强化免疫工作,每年12月5～6日到第二年1月5～6日强化普服糖丸2次,连续强化3年,使我区强化免疫工作取得了很大的进展。 我区1990年以来,脊灰有部分散在性发病,均鉴定是野株型病毒。1994年发病率0.22/10万。

关键词： Genes   Structural   Viral   Point Mutation   Amino Acid Sequence   Base Sequence   DNA Primers   Genetic Complementation Test   Genome   Viral   Genotype   Hela Cells   Humans   Molecular Sequence Data   Mutagenesis   Site-Directed   Open Reading Frames   Phenotype   Plaque Assay   Polioviruses   Polymerase Chain Reaction   Protein Biosynthesis   RNA   Viral   Repetitive Sequences   Nucleic Acid   Research Support   Non-U.S. Gov't   Research Support   U.S. Gov't   P.H.S   Restriction Mapping   Transcription   Genetic   Transfection  

摘要： We report the construction of a poliovirus genome [pPVM-VPg(3F4A)] harboring a double mutation in VPg. This mutant, in which the tyrosine and the threonine at residues 3 and 4 of the VPg region were replaced by phenylalanine and alanine, respectively, is lethal, that is, all RNA synthesis was abolished and no revertants could be isolated. Using the properties of dicistronic polioviruses (with the general genotype PV 5'NTR-3AB-EMCV IRES-PV ORF-3'NTR), we have observed that the defect in RNA synthesis of the VPg(3F4A) mutant could be rescued by providing wild-type protein 3AB from the first open reading frame in trans. We conclude that the 3AB provided by the first cistron of the dicistronic construct was capable of ''intragenomic complementation.'' Intragenomic complementation, however, was inefficient. Thus, the dicistronic RNAs were only quasi-infectious, and even first-passage viruses were found to have reverted to a functioning VPg in the polyprotein. This phenomenon underlines the role of polypeptide 3AB in multiple functions of viral proliferation. First-passage viruses, all of which expressed a small-plaque phenotype, had retained the original dicistronic genotype. At the fourth passage, however, all isolates were monocistronic, and they displayed complex genetic rearrangements revealing interesting information regarding IRES function. (C) 1995 Academic Press, Inc.

关键词： 消灭脊髓灰质炎   输入病例   暴发流行   野生病毒   脊灰病毒   加拿大   消灭脊灰   脊髓灰质炎病毒   免疫接种   病毒感染  

摘要： 加拿大安大略疾病控制中心实验室的区域流行病学家爱德华·本持西·英切尔博士说,尽管西半球国家已被证实消灭了脊髓灰质炎,但它们仍需不断地注意,以防备脊髓灰质炎病毒从脊灰仍然流行的国家输入。如果放松警惕,该病就可能复活、持续。 当最后一个病例在秘鲁加宁发生后,尽管加强了对急性弛缓型麻痹病例的监视,从1991年8月以来在美洲仍没有查出脊灰病例。证实在西半球消灭脊灰的消息是在1994年9月29日正式宣布的。

关键词： 二氧化氯消毒   消毒剂   失活效果   动物病毒   脊髓灰质炎病毒   水中病毒   柯萨奇病毒   艾可病毒   腮腺炎病毒   投量  

摘要： 引言研究了二氧化氯（CIO₂）对水体中一些主要病毒的消毒效果。考察了不同试验条件。如消毒剂投量。不同接触时间和pH值等条件下二氧化氯对病毒杀灭失活效果。与液氯（CI₂）比较。

关键词： Point Mutation   Poliovirus Vaccine   Oral   Amino Acid Sequence   Animals   Base Sequence   Cell Line   Cercopithecus aethiops   Comparative Study   DNA Primers   DNA   Complementary   DNA   Viral   Kidney   Molecular Sequence Data   Polioviruses   Polymerase Chain Reaction   RNA   Viral   Research Support   Non-U.S. Gov't   Restriction Mapping   Vero Cells   Virulence  

摘要： Mutations that consistently accumulated in the attenuated Sabin 2 strain of poliovirus during propagation in cell cultures were identified by sequence heterogeneity assay and quantified by mutant analysis by PCR and restriction enzyme cleavage (MAPREC). Eight additional sites previously identified in stool isolates were also examined by MAPREC in the virus passages. The pattern of selectable mutations and the rate of their accumulation depended on the type and confluence of the cell culture and the temperature of virus growth. Five unstable genomic sites were identified in Sabin 2 virus passaged 10 times at 34 degrees in African green monkey kidney (AGMK) cells, with the mutations accumulating in the range 1 to 24%. Accumulation of these mutations did not appear to result in a loss of attenuated phenotype since the virus passaged under these conditions passed the monkey neurovirulence test (MNVT). The content of the 481-G revertant known to be related to neurovirulence in monkeys did not increase. Thus, our results suggest that upon growth of Sabin 2 virus in AGMK cells at 34 degrees, the key determinant(s) of attenuation remained stable, and the mutations that occurred did not affect monkey neurovirulence. In virus passaged 10 times at 37 degrees in AGMK cells, 4 unstable genomic sites were identified, in some of them accumulating up to 12% of the mutants. This virus sample severely failed the MNVT. Virus passaged in Vero cells at 34 and 37 degrees accumulated mutants at 7 and 14 genomic sites, respectively, including 481-G in both cases, with almost complete substitution of the original nucleotides at some of the sites. We tested 44 commercial monopools of Type 2 OPV and found out that all of them contained 481-G revertants in the range 0.4-1.1%. An increase in the 481-G revertants in passaged viruses to the level of 4% and above correlated with failure of these samples by the MNVT. Since the pattern of selectable mutations differed in viruses grown in the two cel