关键词： Poliovirus   non-neurovirulent clone  

摘要： A clone of poliovirus type III (TRU-3) was derived from the Sabin-3 vaccine strain by the cDNA: RNA hybrid molecular cloning method. The virus recovered was found to be considerably less neurovirulent for primates than its progenitor Sabin III vaccine strain. Upon serial passages in humans, TRU-3 did not increase its neurovirulence (unlike the Sabin strain) and maintained the base sequence of the attenuated strain in a crticial part of the 5'' region of the genome (unlike the Sabin strain). The substitution of TRU-3 clone for Sabin type III in oral polio vaccine could eliminate the vast majority of cases of vaccine-associated poliomyelitis.

摘要： A clinical case of paralytic poliomyelitis with almost simultaneous isolation of two different types of poliovirus was investigated. A strain of poliovirus type 1 was isolated from the cerebrospinal fluid and a type 3 strain of poliovirus was isolated from the patient's faeces. Both strains were characterised by two-dimensional oligonucleotide mapping. The type 1 virus was shown to be of wild type while the type 3 virus was shown to be vaccine-associated.

摘要： Poliovirus type 2 (PV-2) Lansing strain produces a fatal paralytic disease in mice after intracerebral injection, whereas poliovirus type 1 (PV-1) Mahoney strain causes disease only in primates. Atomic models derived from the three-dimensional crysal structure of the PV-1 Mahoney strain have been used to locate three antigenic sites on the surface of the virion. We report here the construction of type 1-type 2 chimaeric polioviruses in which antigenic site 1 from the PV-1 Mahoney strain was substituted by that of the PV-2 Lansing strain by nucleotide cassette exchange in a cloned PV-1 cDNA molecule. These chimaeras proved to have mosaic capsids with composite type 1 and type 2 antigenicity, and induced a neutralizing response against both PV-1 and PV-2 when injected into rabbits. Moreover, a six-aminoacid change in PV-1 antigenic site 1 was shown to be responsible for a remarkable host-range mutation in so far as one of the two type 1-type 2 chimaera was highly neurovirulent for mice.

关键词： Acetyltransferases/genetics   Animals   Cell Line   Cell-Free System   Cercopithecus aethiops   Chloramphenicol O-Acetyltransferase   DNA Mutational Analysis   DNA, Recombinant   Poliovirus/genetics   Protein Biosynthesis   RNA Caps   RNA, Messenger/genetics  

摘要： The central portion (region P) of the 742-nucleotide noncoding 5'' end of poliovirus allows the RNA to initiate protein synthesis in the absence of the usual 5'' 7-methylguanosine capping group. Poliovirus 5'' noncoding region was fused to a reporter gene and transfected into cells. There was extensive augmentation of the expression of this gene by poliovirus-mediated inhibition of cap-dependent protein synthesis. That the construct initiated in a cap-independent manner was verified through in vitro experiments. Small lesions throughout region P blocked its initiation function, implying that a coherent functional unit, hundreds of nucleotides long, is responsible for cap-independent initiation by poliovirus RNA.

关键词： Animals   Antibodies, Viral/immunology   Antigens, Viral/physiology   Capsid/physiology   DNA Mutational Analysis   Mice   Nervous System Diseases/microbiology   Neutralization Tests   Neutralization Tests   Poliovirus/growth & development   Poliovirus/immunology   Poliovirus/pathogenicity   Virus Replication  

摘要： The mouse-adapted strain of poliovirus type 2 (Lansing) induces fatal poliomyelitis in mice after intracerebral inoculation, whereas mice inoculated with poliovirus type 1 (Mahoney) show no signs of disease. Previous work indicated that the adaptation to mouse virulence is associated with the viral capsid proteins and that mutations in neutralization antigenic site I of poliovirus reduce neurovirulence of the Lansing strain in mice. The role of antigenic site I in mouse neurovirulence was further explored by constructing an antigen hybrid virus. Six amino acids in antigenic site I of the Mahoney strain were replaced with a sequence specific for the Lansing strain by using a mutagenesis cartridge. The hybrid virus was neutralized by polyclonal antisera elicited by the type 1 and type 2 strains of poliovirus and by neutralizing monoclonal antibodies directed against antigenic site I of type 2 virus. The hybrid virus induced paralytic disease in mice, an observation demonstrating that a short sequence of amino acids in antigenic site I is an important determinant of poliovirus host range. Antigenic site I may be involved in attachment of poliovirus to cells of the mouse central nervous system.

关键词： 脊髓灰质炎病毒   提取   网织红细胞   溶解物  

关键词： 污水处理工艺   柯萨奇病毒   去除效果   城市污水   脊髓灰质炎病毒   污水回用   生活污水   去除率   城市水资源   污水处理设备  

摘要： 城市水资源的紧缺,迫使人们不得不将城市污水经处理后重复利用于工业及生活杂用。由于污水中含有大量致病微生物,而污水从产出到回收利用,其时间间隔又较短(约一天)。因此,在回用污水过程中,必须密切注意由水病毒引发疾病流行的可能性。

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： The 1986-87 outbreak of paralytic poliomyelitis in Senegal, with 676 reported cases, provided an opportunity to evaluate the efficacy of an enhanced-potency inactivated poliovirus vaccine (N-IPV) in the Kolda region, where this vaccine has been used since 1980. 89 cases, confirmed to have poliomyelitis with residual paralysis, were enrolled in a case-control study, up to 5 matched controls being obtained for each case. The clinical efficacy for one dose of N-IPV was 36% (95% confidence interval 0%, 67%) and for two doses was 89% (95% CI 62%, 97%).