Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| comparison of panbio dengue duo igm and igg capture elisa and venture technologies dengue igm and igg dot blot. | a number of commercial elisa for dengue diagnosis have recently become available, though direct comparison between these assays have not been published. | 2000 | 10720818 |
| bovine viral diarrhoea virus and bovine herpesvirus-1 prime uninfected macrophages for lipopolysaccharide-triggered apoptosis by interferon-dependent and -independent pathways. | the flavivirus bovine viral diarrhoea (bvd) virus exists in two biotypes, cytopathic (cp) and non-cytopathic (ncp), defined by their effect on cultured cells. cp bvd virus-infected cells undergo apoptosis and may promote apoptosis in uninfected cells by an indirect mechanism. macrophages (mφ) infected with cp, but not ncp, bvd virus release a factor(s) in the supernatant capable of priming uninfected mφ for activation-induced apoptosis in response to lipopolysaccharide. a possible role o ... | 2000 | 10725412 |
| prevalence of hepatitis g virus in patients with hemophilia and their steady female sexual partners. | hepatitis g virus (hgv), also known as gb virus c, is a newly discovered flavivirus that is transmissible by blood transfusion and other possible routes. | 2000 | 10726654 |
| role of the dexh motif of the japanese encephalitis virus and hepatitis c virus ns3 proteins in the atpase and rna helicase activities. | the role of the conserved dexh motif of the japanese encephalitis virus (jev) ns3 protein in the atpase and rna helicase activities was compared with that of the hepatitis c virus (hcv) ns3 protein. in the dexh motif of jev ns3, asp-285 and glu-286 were essential for both atpase and rna helicase activities. cys-287 was critical for the rna helicase activity of jev ns3 but not for atpase activity. a his-288-to-ala substitution in the dexh motif of hcv ns3 resulted in an increase in atpase activit ... | 2000 | 10915602 |
| cross-genotypic interaction between hepatitis c virus ns3 protease domains and ns4a cofactors. | hepatitis c virus (hcv) nonstructural protein 3 (ns3) protease requires ns4a as a cofactor. this cofactor activity has been mapped to the central region of ns4a which interacts with the n-terminus of ns3 protease. to investigate whether this interaction is conserved among different genotypes of hcv cross-genotypic characterization were performed to delineate the importance of ns4a cofactor function in relation to the molecular evolution of hcv methods: active ns3 protease domains of genotype 1-3 ... | 2000 | 10735621 |
| purified ns2b/ns3 serine protease of dengue virus type 2 exhibits cofactor ns2b dependence for cleavage of substrates with dibasic amino acids in vitro. | dengue virus type 2 ns3, a multifunctional protein, has a serine protease domain (ns3pro) that requires the conserved hydrophilic domain of ns2b for protease activity in cleavage of the polyprotein precursor at sites following two basic amino acids. in this study, we report the expression of the ns2b-ns3pro precursor in escherichia coli as a fusion protein with a histidine tag at the n terminus. the precursor was purified from insoluble inclusion bodies by ni(2+) affinity and gel filtration chro ... | 2000 | 10744671 |
| human skin langerhans cells are targets of dengue virus infection. | dengue virus (dv), an arthropod-borne flavivirus, causes a febrile illness for which there is no antiviral treatment and no vaccine. macrophages are important in dengue pathogenesis; however, the initial target cell for dv infection remains unknown. as dv is introduced into human skin by mosquitoes of the genus aedes, we undertook experiments to determine whether human dendritic cells (dcs) were permissive for the growth of dv. initial experiments demonstrated that blood-derived dcs were 10-fold ... | 2000 | 10888933 |
| virus-specific cofactor requirement and chimeric hepatitis c virus/gb virus b nonstructural protein 3. | gb virus b (gbv-b) is closely related to hepatitis c virus (hcv) and causes acute hepatitis in tamarins (saguinus species), making it an attractive surrogate virus for in vivo testing of anti-hcv inhibitors in a small monkey model. it has been reported that the nonstructural protein 3 (ns3) serine protease of gbv-b shares similar substrate specificity with its counterpart in hcv. authentic proteolytic processing of the hcv polyprotein junctions (ns4a/4b, ns4b/5a, and ns5a/5b) can be accomplished ... | 2000 | 10756044 |
| stable high-level expression of heterologous genes in vitro and in vivo by noncytopathic dna-based kunjin virus replicon vectors. | primary features of the flavivirus kunjin (kun) subgenomic replicons include continuous noncytopathic replication in host cell cytoplasm and the ability to be encapsidated into secreted virus-like particles (vlps). previously we reported preparation of rna-based kun replicon vectors and expression of heterologous genes (hg) in cell culture after rna transfection or after infection with recombinant kun vlps (a. n. varnavski and a. a. khromykh, virology 255:366-375, 1999). in this study we describ ... | 2000 | 10756054 |
| rna viruses: emerging vectors for vaccination and gene therapy. | the application of modern molecular techniques has profoundly influenced our understanding of virus function. as a consequence, virus biology is being directly applied to medical research. it is a reflection of the current pace of virology that we are now beginning to think of our ancient foes as useful and beneficial tools. | 2000 | 10637572 |
| chimeric yellow fever virus 17d-japanese encephalitis virus vaccine: dose-response effectiveness and extended safety testing in rhesus monkeys. | chimerivax-je is a live, attenuated recombinant virus prepared by replacing the genes encoding two structural proteins (prm and e) of yellow fever 17d virus with the corresponding genes of an attenuated strain of japanese encephalitis virus (je), sa14-14-2 (t. j. chambers et al., j. virol. 73:3095-3101, 1999). since the prm and e proteins contain antigens conferring protective humoral and cellular immunity, the immune response to vaccination is directed principally at je. the prm-e genome sequen ... | 2000 | 10644345 |
| mutagenesis of the signal sequence of yellow fever virus prm protein: enhancement of signalase cleavage in vitro is lethal for virus production. | proteolytic processing at the c-prm junction in the flavivirus polyprotein involves coordinated cleavages at the cytoplasmic and luminal sides of an internal signal sequence. we have introduced at the cooh terminus of the yellow fever virus (yfv) prm signal sequence amino acid substitutions (vpqaqa mutation) which uncoupled efficient signal peptidase cleavage of the prm protein from its dependence on prior cleavage in the cytoplasm of the c protein mediated by the viral ns2b-3 protease. infectiv ... | 2000 | 10590087 |
| mother-to-infant transmission of gb virus type c/hgv. | the potentially hepatotropic flavivirus-like virus, gb virus type c (gbv-c)/hgv, has been detected in a few patients with acute and chronic hepatitis and in a certain proportion of blood donors and recipients of blood or blood components. | 2000 | 10864996 |
| human recombinant laminin-binding protein: isolation, purification, and crystallization. | the mrna of the precursor of laminin-binding protein (lbp) was isolated from a human embryo kidney cell line and cloned. the determined sequence of the lbp gene showed complete identity with the lbp genes isolated from human lung and large intestine cells. the human lbp was expressed by e. coli cells, and it was purified using ni-nta-sepharose chromatography. the mobility of the homogeneous recombinant human laminin-binding protein on sds-page was 43 kd. a mixture of eight murine monoclonal anti ... | 2000 | 10851030 |
| a model for the hepatitis c virus envelope glycoprotein e2. | several experimental studies on hepatitis c virus (hcv) have suggested the envelope glycoprotein e2 as a key antigen for an effective vaccine against the virus. knowledge of its structure, therefore, would present a significant step forward in the fight against this disease. this paper reports the application of fold recognition methods in order to produce a model of the hcv e2 protein. such investigation highlighted the envelope protein e of tick borne encephalitis virus as a possible template ... | 2000 | 10861927 |
| solid phase synthesis of aminoboronic acids: potent inhibitors of the hepatitis c virus ns3 proteinase. | use of a resin bound diol as a boronic acid protecting group has been developed to allow the parallel synthesis of potent inhibitors of the hepatitis c virus ns3 serine proteinase. | 2000 | 10915055 |
| [the immune state against yellow fever vaccinal virus (17d) in 2 populations of bahia state, brazil]. | the occurrence of cases of yellow fever (yf) and also the extensive distribution of a. aegypti in brazil, inspired a study about the estimate of immunity against vaccinal virus (17d) among the residents at two cities of the bahia state, ipupiara (n = 461) and prado (n = 228). at this non-endemic area of yf, the search for serology antibody against 17d (ab17d) and 18 another arbovirus was made thereby hemagglutination inhibition (hi). only 1.2% (8/689) showed ab17d, six of those with monotypic so ... | 2000 | 10881117 |
| ns3 serine protease of bovine viral diarrhea virus: characterization of active site residues, ns4a cofactor domain, and protease-cofactor interactions. | the gene expression of bovine viral diarrhea virus (bvdv), a pestivirus, occurs via translation of a hypothetical polyprotein that is processed cotranslationally and posttranslationally by viral and cellular enzymes. a protease located in the n-terminal region of nonstructural (ns) protein ns3 catalyzes the cleavages, leading to the release of ns4a, ns4b, ns5a, and ns5b. our study provides experimental evidence that histidine at position 1658 and aspartic acid at position 1686 constitute togethe ... | 2000 | 10915606 |
| [ocular manifestation in dengue fever]. | dengue-fever is a mosquito transmitted viral disease. it is endemic mainly in south-east asia and africa. the clinical manifestation is divided into different stages. ocular manifestations in travellers have been rarely reported. | 2000 | 10916388 |
| recombinant plasmid expressing a truncated dengue-2 virus e protein without co-expression of prm protein induces partial protection in mice. | a nucleic acid vaccine candidate against dengue-2 virus was constructed to express a truncated dengue-2 e glycoprotein without concomitant expression of prm. the truncated e protein was properly expressed even in the absence of prm. mice inoculated intramuscularly with the recombinant plasmid containing 94% of the e gene did not respond with anti-dengue antibodies, cellular proliferation, or synthesis of cytokines by their lymphoid cells when stimulated with purified dengue-2 virus. however, pro ... | 2000 | 11090717 |
| [identification of the encephalitis equine virus, parana, brazil]. | in the period of 1996-1999 some virus associated with encephalitis have been reported in horses from different regions of paraná state, brazil. to identify the etiologic agent associated with this illness, mosquitoes and serum samples were collected in the endemic area. | 2000 | 10920444 |
| [serological survey on arbovirus infection in residents of an ecological reserve]. | serological inquires conducted in the ribeira valley, s. paulo state, brazil, showed an intense circulation of pathogenic arboviruses in the region. the goal was to verify the prevalence of arboviral infections in people living at the local ecological, and its potential association with these population' individual and familiar characteristics. | 2000 | 10920445 |
| chimeric yellow fever/dengue virus as a candidate dengue vaccine: quantitation of the dengue virus-specific cd8 t-cell response. | we have constructed a chimeric yellow fever/dengue (yf/den) virus, which expresses the premembrane (prm) and envelope (e) genes from den type 2 (den-2) virus in a yf virus (yfv-17d) genetic background. immunization of balb/c mice with this chimeric virus induced a cd8 t-cell response specific for the den-2 virus prm and e proteins. this response protected yf/den virus-immunized mice against lethal dengue encephalitis. control mice immunized with the parental yfv-17d were not protected against de ... | 2000 | 10933719 |
| recent advances in prevention and treatment of hepatitis c virus infections. | hepatitis c virus (hcv) is the leading cause of chronic hepatitis in humans. as members of the flavivirus family, hcvs are a group of small single-stranded, positive-sense rna viruses. upon translation of the genome, a polyprotein precursor is synthesized and further processed by both cellular and viral proteases to generate functional viral proteins. treatment options are currently limited to the administration of alpha-interferon alone or in combination with ribavirin. unfortunately, these app ... | 2000 | 11127961 |
| the yellow fever 17d vaccine virus as a vector for the expression of foreign proteins: development of new live flavivirus vaccines. | the flaviviridae is a family of about 70 mostly arthropod-borne viruses many of which are major public health problems with members being present in most continents. among the most important are yellow fever (yf), dengue with its four serotypes and japanese encephalitis virus. a live attenuated virus is used as a cost effective, safe and efficacious vaccine against yf but no other live flavivirus vaccines have been licensed. the rise of recombinant dna technology and its application to study fla ... | 2000 | 11142718 |
| gbv-c/hgv genotypes: proposed nomenclature for genotypes 1-5. | the gb virus-c and hepatitis g virus (gbv-c/hgv) are variants of the same flavivirus. this proposal attempts to clarify the conflicting nomenclature for gbv-c/hgv genotypes. the first three genotypes described were genotype 1 (west africa); genotype 2 (us/europe) and genotype 3 (asia). subsequently, two groups published data from south africa and southeast asia both stating the presence of a novel "4th genotype." these isolates are distinct phylogenetically. it is proposed that the nomenclature ... | 2000 | 10935992 |
| chimeric langat/dengue viruses protect mice from heterologous challenge with the highly virulent strains of tick-borne encephalitis virus. | langat virus (lgt), a tick-borne flavivirus, is naturally attenuated for humans but it is very virulent in scid mice. in contrast, viable recombinant chimeras of lgt (prem and e genes) and dengue type 4 virus (all other sequences) recovered in mosquito cell culture were completely attenuated in scid mice but still capable of providing protection against lgt. to develop the chimeras into vaccine candidates, we adapted them to replicate efficiently in simian vero cells, a satisfactory substrate fo ... | 2000 | 10936085 |
| processing of gb virus b non-structural proteins in cultured cells requires both ns3 protease and ns4a cofactor. | the identification of antivirals and vaccines against hepatitis c virus (hcv) infection is hampered by the lack of convenient animal models. the need to develop surrogate models has recently drawn attention to gb virus b (gbv-b), which produces hepatitis in small primates. in a previous study in vitro, it was shown that gbv-b ns3 protease shares substrate specificity with the hcv enzyme, known to be crucial for virus replication. in this report, gbv-b ns3 activity on gbv-b precursor proteins has ... | 2000 | 10950975 |
| dengue infection presenting with central nervous system manifestation. | the objective of this study was to investigate the possibility of dengue virus infection causing an abnormal neurologic presentation. between 1996 and 1998, all pediatric patients with clinical manifestations of encephalitis-like illness who were admitted to the department of pediatrics, siriraj hospital were prospectively studied for any evidence of dengue virus infection. the diagnosis of dengue virus infection was based on mosquito viral isolation and serologic and polymerase chain reaction ( ... | 2000 | 10961794 |
| crystal structure of dengue virus ns3 protease in complex with a bowman-birk inhibitor: implications for flaviviral polyprotein processing and drug design. | dengue viruses are members of the flaviviridae and cause dengue fever and the more severe dengue hemorrhagic fever. although nearly 40 % of the world's population is at risk of dengue infection, there is currently no effective vaccine or chemotherapy for the disease. processing of the dengue polyprotein into structural and non-structural proteins in a host, which is essential for assembly of infective virions, is carried out by the combined action of host proteases and the trypsin-like, two-comp ... | 2000 | 10966782 |
| hepatitis c virus internal ribosome entry site (ires) stem loop iiid contains a phylogenetically conserved ggg triplet essential for translation and ires folding. | the hepatitis c virus (hcv) internal ribosome entry site (ires) is a highly structured rna element that directs cap-independent translation of the viral polyprotein. morpholino antisense oligonucleotides directed towards stem loop iiid drastically reduced hcv ires activity. mutagenesis studies of this region showed that the ggg triplet (nucleotides 266 through 268) of the hexanucleotide apical loop of stem loop iiid is essential for ires activity both in vitro and in vivo. sequence comparison sh ... | 2000 | 11044087 |
| heparan sulfate proteoglycans initiate dengue virus infection of hepatocytes. | dengue viruses (den) cause a broad spectrum of clinical manifestations including potentially life-threatening conditions such as hemorrhagic shock syndrome and less frequently acute hepatitis with liver failure and encephalopathy. in addition, dengue viruses provide a potential model to understand the initiation of hepatocyte infection by the structurally closely related hepatitis c virus (hcv), because this virus at present cannot be grown in cell culture. although the initial steps of viral in ... | 2000 | 11050058 |
| [prevalence of flavivirus antibodies in alouatta caraya primate autochthonous of argentina]. | flavivirus constitute a human health problem in our country. primates are known to participate in the maintenance of dengue and yellow fever viruses. however, these animals play a role which still remains to be determined in the maintenance of other viruses with potential pathogenicity for human beings and/or animals. detección of antibodies was performed for different flavivirus in 105 sera samples of alouatta caraya primates by the hemagglutination inhibition (hi) test. the neutralization (nt) ... | 2000 | 11050814 |
| structures and mechanisms in flavivirus fusion. | 2000 | 11050944 | |
| tick-borne encephalitis virus strains of western siberia. | tick-borne encephalitis virus (tbev) strains were isolated from ticks in western siberia for 12 years. molecular hybridization of the 46 viral rna with the tbev cdna and oligonucleotide probes revealed differences between the siberian and far eastern strains. a comparison of the viral e gene fragment nucleotide sequence showed 89-98% homology between siberian tbev strains, whereas their similarity with strains from other populations was less than 83%. however, the viral e and ns1 glycoprotein an ... | 2000 | 11074120 |
| [tick-borne meningoencephalitis in thurgau canton: a clinical and epidiomological analysis]. | tick-borne meningo-encephalitis (tbe) is caused by a flavivirus species that is transmitted from rodents to humans by ixodes ticks. the clinical picture of central nervous system involvement varies from febrile headache to lethal encephalitis. to date no specific treatment exists, although protective active immunisation is available. | 2000 | 11075408 |
| trends in flavivirus infections in japan. | although japanese encephalitis has declined as an important cause of illness and death in japan, infection with other flaviviruses has become a public health concern. recently, reports of imported dengue cases, as well as isolations of tick-borne encephalitis virus, have increased. | 2000 | 11076713 |
| genetic heterogeneity and molecular epidemiology of gb virus c/hepatitis g virus in china. | the inter- and intrapatient genetic variation of gb virus c (gbv-c)/hepatitis g virus (hgv) was investigated to characterize the molecular epidemiologic profile of gbv-c/ hgv infection in china, an area endemic for viral hepatitis. the intrapatient variation of hepatitis c virus (hcv) from the same patients was compared to that of gbv-c/hgv. | 2000 | 11100910 |
| the brazilian flaviviruses. | ten flaviviruses occur in brazil: bussuquara, cacipacoré, dengue 1, 2 and 4, iguape, ilhéus, rocio, saint louis encephalitis and yellow fever. aspects of sylvatic maintenance cycles and human diseases caused by these viruses are analyzed. large dengue outbreaks are occurring in brazil and there is a risk of yellow fever urbanization. | 2000 | 11113383 |
| the rna aptamer-binding site of hepatitis c virus ns3 protease. | nonstructural protein 3 (ns3) of hepatitis c virus (hcv) is a trypsin-like protease and is essential for processing of viral polyprotein. accordingly, it is a potential target for anti-hcv drugs. recently we could isolate rna aptamers (g9-i, ii, and iii) which bind and inhibit ns3 protease using in vitro selection strategy. in addition, g9-i aptamer showed noncompetitive inhibition. in order to elucidate the binding site of g9-i aptamer in ns3 protease domain (deltans3), we carried out alanine s ... | 2000 | 11118325 |
| modulatory effects of the human heat shock protein 70 on dna vaccination. | dna vaccination with the plasmid expressing japanese encephalitis virus (jev) nonstructural protein 1 (pjns1) has been shown to induce effective immunity against jev infection. to further increase the efficacy of pjns1 dna vaccination, we coinjected pjns1 with a plasmid that expresses heat shock protein 70.1 (phsp70.1) into mice. we found that coinjection of phsp70.1 enhanced both t cell proliferation and cytotoxic effects, but not the antibody response to jev. moreover, mice immunized with both ... | 2000 | 10971139 |
| substitutions at the putative receptor-binding site of an encephalitic flavivirus alter virulence and host cell tropism and reveal a role for glycosaminoglycans in entry. | the flavivirus receptor-binding domain has been putatively assigned to a hydrophilic region (fg loop) in the envelope (e) protein. in some flaviviruses this domain harbors the integrin-binding motif arg-gly-asp (rgd). one of us has shown earlier that host cell adaptation of murray valley encephalitis virus (mve) can result in the selection of attenuated variants altered at e protein residue asp(390), which is part of an rgd motif. here, a full-length, infectious cdna clone of mve was constructed ... | 2000 | 10982329 |
| full-length gb virus c (hepatitis g virus) rna transcripts are infectious in primary cd4-positive t cells. | gb virus c (gbv-c or hepatitis g virus) is a recently described flavivirus which frequently leads to chronic viremia in humans. although gbv-c is associated with acute posttransfusion hepatitis, it is not clear if the virus is pathogenic for humans. we constructed a full-length cdna from the plasma of a person with chronic gbv-c viremia. peripheral blood mononuclear cells (pbmcs) transfected with full-length rna transcripts from this gbv-c clone resulted in viral replication. this was demonstrat ... | 2000 | 10982359 |
| gb virus c/hepatitis g virus replicates in human haematopoietic cells and vascular endothelial cells. | a novel flavivirus, gb virus c (gbv-c)/hepatitis g virus (hgv), has been detected in chronic liver disease patients. it is known that the viral rna can be detected in approximately 5% of american blood donors. however, the implications for liver disease and the sites of virus replication remain unknown. possible sites of virus replication were studied by using cell lines and/or primary cells derived from human lymphoid cells, myeloid cells, hepatocytes and endothelial cells. rna was detected by ... | 2000 | 10993934 |
| yellow fever virus ns2b-ns3 protease: charged-to-alanine mutagenesis and deletion analysis define regions important for protease complex formation and function. | charged-to-alanine substitutions and deletions within the yellow fever virus ns2b-ns3(181) protease were analyzed for effects on protease function. during cell-free translation of ns2b-3(181) polyproteins, mutations at three charge clusters markedly impaired cis cleavage activity: a single n-terminal cluster in the conserved domain of ns2b (residues elkk(52-55)) and two in ns3 (ed(21-22), and residue h(47)). these mutations inhibited other protease-dependent cleavages of a transiently expressed ... | 2000 | 10998334 |
| attenuation of tick-borne encephalitis virus by structure-based site-specific mutagenesis of a putative flavivirus receptor binding site. | the impact of a specific region of the envelope protein e of tick-borne encephalitis (tbe) virus on the biology of this virus was investigated by a site-directed mutagenesis approach. the four amino acid residues that were analyzed in detail (e308 to e311) are located on the upper-lateral surface of domain iii according to the x-ray structure of the tbe virus protein e and are part of an area that is considered to be a potential receptor binding determinant of flaviviruses. mutants containing si ... | 2000 | 11000232 |
| prospective follow-up of patients with gbv-c/hgv infection: specific mutational patterns, clinical outcome, and genetic diversity. | an association between a specific mutational pattern within the nonstructural (ns)3 region of gb virus-c/hepatitis g virus (gbv-c/hgv) genome and fulminant hepatic failure has been suggested recently. the mutational pattern consists of 3-6 nucleotide mutations of which one is leading to an amino acid exchange. in the present study, patients with gbv-c/hgv mono-infection (n = 24) or gbv-c/hgv and hcv co-infection (n = 20) were investigated prospectively. in 6/44 patients (14%) the mutational patt ... | 2000 | 11002248 |
| japanese encephalitis. | japanese encephalitis (je) virus is a mosquito-borne flavivirus that can cause encephalitis and death in horses and humans. it is an emerging disease of international concern because it has been spreading into previously nonendemic areas. major epidemics may occur where the virus moves into new areas, but many infections are subclinical. this article presents information on the virus, its epidemiology, and what little information has been published on the disease in horses. the methods available ... | 2000 | 11219350 |
| single amino acid differences are sufficient for cd4(+) t-cell recognition of a heterologous virus by cattle persistently infected with bovine viral diarrhea virus. | cattle that are persistently infected (pi) with one strain of bovine viral diarrhea virus (bvdv) can resolve infection with a second, antigenically heterologous strain but not the homologous strain. since cd4(+) t cells are thought to be critical for the resolution of acute bvdv infection (howard et al., 1992, vet. immunol. immunopathol. 32, 303-314), we have examined the recognition of a heterologous virus (nadl) by cd4(+) t cells from pe515-pi animals. the immune response of non-pi control cat ... | 2000 | 11021996 |
| stable expression of noncytopathic kunjin replicons simulates both ultrastructural and biochemical characteristics observed during replication of kunjin virus. | this report focuses mainly on the characterization of a vero cell line stably expressing the flavivirus kunjin (kun) replicon c20sdrep (c20sdrepvero). we showed by immunofluorescence and cryoimmunoelectron microscopy that unique flavivirus-induced membrane structures, termed convoluted membranes/paracrystalline structures, were induced in the c20sdrepvero cells. these induced cytoplasmic foci were immunolabeled with kun virus anti-ns3 antibodies and with antibodies to the cellular markers ergic5 ... | 2001 | 11145899 |
| expression and purification of enzymatically active recombinant rna-dependent rna polymerase (ns5) of the flavivirus kunjin. | the ns5 protein of the flavivirus kunjin (kun) contains conserved sequence motifs characteristic of rna-dependent rna polymerase (rdrp) activity. to investigate this activity in vitro, recombinant ns5 proteins with c-terminal (ns5chis) and n-terminal (ns5nhis) hexahistidine tags were produced in baculovirus-infected insect cells and purified to near homogeneity by nickel affinity chromatography. purified ns5chis exhibited rdrp activity with both specific (9 kb kun replicon) and non-specific (8.3 ... | 2001 | 11164916 |
| distribution and characterization of tick-borne encephalitis viruses from siberia and far-eastern asia. | in this study, tick-borne encephalitis (tbe) viruses from siberia and far-eastern asia were characterized in order to determine virus subtype distribution. tbe viruses were isolated from ticks (ixodes persulcatus) collected in the far-eastern (khabarovsk and vladivostok) and siberian (irkutsk) regions of russia in 1999. phylogenetic analysis showed that isolates formed distinct clusters of far-eastern and siberian subtypes. there was also a minor difference in antigenicity between the irkutsk is ... | 2001 | 11369875 |
| role of metastability and acidic ph in membrane fusion by tick-borne encephalitis virus. | the envelope protein e of the flavivirus tick-borne encephalitis (tbe) virus is, like the alphavirus e1 protein, a class ii viral fusion protein that differs structurally and probably mechanistically from class i viral fusion proteins. the surface of the native tbe virion is covered by an icosahedrally symmetrical network of e homodimers, which mediate low-ph-induced fusion in endosomes. at the ph of fusion, the e homodimers are irreversibly converted to a homotrimeric form, which we have found ... | 2001 | 11462011 |
| [secondary serologic responses to dengue epidemic in 1998 in salta, argentina, where other flavivirus co-circulate]. | in 1998, a dengue outbreak (serotype 2) occurred in salta province in northern argentina, following the first detection of dengue in the same area in 1997. we classified the serologic response of cases from 1998 as primary or secondary, since the risk of severe disease is greater for secondary cases. we studied 154 cases by plaque reduction neutralization and hemagglutination inhibition tests. thirty-eight cases (25%) were classified as primary serologic responses and 84 cases (54%) as secondary ... | 2001 | 11374133 |
| immunogenicity of two peptide determinants in the cytolytic t-cell response to flavivirus infection: inverse correlation between peptide affinity for mhc class i and t-cell precursor frequency. | we used the cd8+ cytotoxic t (tc) cell immune response against the flavivirus, murray valley encephalitis virus (mve), restricted by the h-2kk major histocompatibility complex (mhc) class i molecule, to investigate immunodominance. split-clone limiting dilution analysis revealed almost exclusive recognition of two peptides, mve1785 and mve1971, derived from the viral ns3 protein. the precursor frequency of mve-reactive tc cells was determined by limiting dilution analysis for cytotoxic function ... | 2001 | 11398809 |
| chemical mutagenesis of dengue virus type 4 yields mutant viruses which are temperature sensitive in vero cells or human liver cells and attenuated in mice. | a recombinant live attenuated dengue virus type 4 (den4) vaccine candidate, 2adelta30, was found previously to be generally well tolerated in humans, but a rash and an elevation of liver enzymes in the serum occurred in some vaccinees. 2adelta30, a non-temperature-sensitive (non-ts) virus, contains a 30-nucleotide deletion (delta30) in the 3' untranslated region (utr) of the viral genome. in the present study, chemical mutagenesis of den4 was utilized to generate attenuating mutations which may ... | 2001 | 11559806 |
| tick-borne encephalitis virus ns1 glycoprotein during acute and persistent infection of cells. | tick-borne encephalitis virus (tbev) was propagated in porcine embryo kidney (ps) cells until 48 h whereas human kidney (rh) cells maintained the virus persistence during at least 2 months. one of possible reasons of flavivirus chronic infection might be abnormal ns1 gene expression. immunoblotting with monoclonal antibodies (mabs) revealed the similarity of the intracellular and secreted ns1 nonstructural glycoprotein size and linear antigenic determinants in both the infected cell lines. howev ... | 2001 | 11410315 |
| mutagenesis of the dengue virus type 2 ns3 proteinase and the production of growth-restricted virus. | the n-terminal one-third of the ns3 protein of dengue virus type 2 (den-2) complexes with co-factor ns2b to form an active serine proteinase which cleaves the viral polyprotein. to identify sites within ns3 that may interact with ns2b, seven regions within the ns3 proteinase outside the conserved flavivirus enzyme motifs were mutated by alanine replacement. five sites contained clusters of charged residues and were hydrophilic. two sites were hydrophobic and highly conserved among flaviviruses. ... | 2001 | 11413376 |
| phylogeny of north american powassan virus. | to determine whether powassan virus (pow) and deer tick virus (dtv) constitute distinct flaviviral populations transmitted by ixodid ticks in north america, we analysed diverse nucleotide sequences from 16 strains of these viruses. two distinct genetic lineages are evident, which may be defined by geographical and host associations. the nucleotide and amino acid sequences of lineage one (comprising new york and canadian pow isolates) are highly conserved across time and space, but those of linea ... | 2001 | 11413377 |
| the degree of attenuation of tick-borne encephalitis virus depends on the cumulative effects of point mutations. | an infectious clone (pggvs) of the tick-borne encephalitis complex virus vasilchenko (vs) was constructed previously. virus recovered from pggvs produced slightly smaller plaques than the vs parental virus. sequence analysis demonstrated five nucleotide differences between the original vs virus and pggvs; four of these mutations resulted in amino acid substitutions, while the fifth mutation was located in the 3' untranslated region (3'utr). two mutations were located in conserved regions and thr ... | 2001 | 11413378 |
| multiple genotypes of st. louis encephalitis virus (flaviviridae: flavivirus) circulate in harris county, texas. | st. louis encephalitis (sle) is endemic in harris county, texas. the disease is a public health concern in houston, the largest city in harris county, and in the state. consequently, intensive surveillance for sle virus in local mosquito populations is carried out by the harris county mosquito control division each year. in this study, we examined genetic variation among sle isolates obtained during routine virus surveillance over a 13-year time period (1986-1999). st. louis encephalitis virus i ... | 2001 | 11425155 |
| monoclonal antibodies that bind to domain iii of dengue virus e glycoprotein are the most efficient blockers of virus adsorption to vero cells. | the specific mechanisms by which antibodies neutralize flavivirus infectivity are not completely understood. to study these mechanisms in more detail, we analyzed the ability of a well-defined set of anti-dengue (den) virus e-glycoprotein-specific monoclonal antibodies (mabs) to block virus adsorption to vero cells. in contrast to previous studies, the binding sites of these mabs were localized to one of three structural domains (i, ii, and iii) in the e glycoprotein. the results indicate that m ... | 2001 | 11462053 |
| [tick-born encephalitis]. | introduction: tick-borne encephalitis (tbe), a disease contracted through tick bites, is caused by a flavivirus. its geographical distribution comes from the geographical distribution of the reservoir of infection--i.e., mainly the tiny mammals living in the forests and bushes. the endemic area spreads from the rhine to the urals, from scandinavia to italy and greece. current knowledge and key points: symptoms usually evolve in three phases: at first a nonspecific phase with fever and myalgia, t ... | 2001 | 11433563 |
| the machinery for flavivirus fusion with host cell membranes. | a combination of structural, biochemical and functional studies with the flavivirus tick-borne encephalitis virus has revealed the characteristics of a new class of viral fusion protein, class ii, that is unrelated to the class i viral fusion proteins for which influenza virus hemagglutinin is the prototype. new structural data have shown that the alphaviruses, another group of icosahedral enveloped viruses, also have class ii fusion proteins, suggesting a common origin. | 2001 | 11495810 |
| phylogenetic and evolutionary relationships among yellow fever virus isolates in africa. | previous studies with a limited number of strains have indicated that there are two genotypes of yellow fever (yf) virus in africa, one in west africa and the other in east and central africa. we have examined the prm/m and a portion of the e protein for a panel of 38 wild strains of yf virus from africa representing different countries and times of isolation. examination of the strains revealed a more complex genetic relationship than previously reported. overall, nucleotide substitutions varie ... | 2001 | 11435580 |
| molecular organization of a recombinant subviral particle from tick-borne encephalitis virus. | the tick-borne encephalitis (tbe) flavivirus contains two transmembrane proteins, e and m. coexpression of e and the m precursor (prm) leads to secretion of recombinant subviral particles (rsps). in the most common form of these rsps, analyzed at a 19 a resolution by cryo-electron microscopy (cryo-em), 60 copies of e pack as dimers in a t = 1 icosahedral surface lattice (outer diameter, 315 a). fitting the high-resolution structure of a soluble e fragment into the rsp density defines interaction ... | 2001 | 11463384 |
| evolution, epidemiology, and dispersal of flaviviruses revealed by molecular phylogenies. | 2001 | 11680389 | |
| flaviviruses isolated from mosquitoes collected during the first recorded outbreak of japanese encephalitis virus on cape york peninsula, australia. | in response to an outbreak of japanese encephalitis (je) virus on cape york peninsula, australia, in 1998, mosquitoes were collected using co2 and octenol-baited centers for disease control and prevention light traps. a total of 35,235 adult mosquitoes, comprising 31 species, were processed for virus isolation. no isolates of je virus were recovered from these mosquitoes. however, 18 isolates of kokobera virus, another flavivirus were obtained from culex annulirostris. twelve isolates were from ... | 2001 | 11442206 |
| [synthesis, immunogenicity and antigenic characteristics of the glycoprotein e fragments from the tick-borne encephalitis virus]. | six peptide fragments of the envelope protein e of the tick-borne encephalitis virus involving the predicted t-helper epitopes were synthesized. their ability to induce antibodies without conjugation with any high-molecular-mass carrier was studied in mice of three lines. five of six synthesized peptides exhibited immunogenic properties, which differed in dependence on the haplotype of immunized mice. the peptide binding to the antiviral antibodies was studied, and two peptides were revealed tha ... | 2001 | 11443938 |
| amino acid substitution(s) in the stem-anchor region of langat virus envelope protein attenuates mouse neurovirulence. | the identification of variants that are unable to bind membrane receptor preparations (mrps) has previously been shown to select attenuated yellow fever and japanese encephalitis viruses. in this study, this methodology has been extended to the tick-borne serocomplex of flaviviruses. langat (lgt) virus strain tp21 was bound to mouse or human brain mrps and viruses that escaped binding were isolated and characterized. in addition, variant viruses escaping neutralization by the monoclonal antibody ... | 2001 | 11448158 |
| phylogenetic relationships of flaviviruses correlate with their epidemiology, disease association and biogeography. | phylogenetic analysis of the flavivirus genus, using either partial sequences of the non-structural 5 gene or the structural envelope gene, revealed an extensive series of clades defined by their epidemiology and disease associations. these phylogenies identified mosquito-borne, tick-borne and no-known-vector (nkv) virus clades, which could be further subdivided into clades defined by their principal vertebrate host. the mosquito-borne flaviviruses revealed two distinct epidemiological groups: ( ... | 2001 | 11457992 |
| pathologic and immunohistochemical findings in naturally occuring west nile virus infection in horses. | the pathologic and peroxidase immunohistochemical features of west nile flavivirus (wnv) infection were compared in four horses from the northeastern united states and six horses from central italy. in all 10 animals, there were mild to severe polioencephalomyelitis with small t lymphocyte and lesser macrophage perivascular infiltrate, multifocal glial nodules, neutrophils, and occasional neuronophagia. perivascular hemorrhages, also noted macroscopically in two animals, were observed in 50% of ... | 2001 | 11467475 |
| terminal nucleotidyl transferase activity of recombinant flaviviridae rna-dependent rna polymerases: implication for viral rna synthesis. | recombinant hepatitis c virus (hcv) rna-dependent rna polymerase (rdrp) was reported to possess terminal transferase (tntase) activity, the ability to add nontemplated nucleotides to the 3' end of viral rnas. however, this tntase was later purported to be a cellular enzyme copurifying with the hcv rdrp. in this report, we present evidence that tntase activity is an inherent function of hcv and bovine viral diarrhea virus rdrps highly purified from both prokaryotic and eukaryotic cells. a change ... | 2001 | 11507207 |
| dengue and other emerging flaviviruses. | flaviviruses are among the most important emerging viruses known to man. most are arboviruses (arthropod-borne) being transmitted by mosquitoes or ticks. they derived from a common ancestor 10-20000 years ago and are evolving rapidly to fill new ecological niches. many are spreading to new geographical areas and causing increased numbers of infections. traditionally, three clinical syndromes are recognized: fever-arthralgia-rash, viral haemorrhagic fever, and neurological disease, though for som ... | 2001 | 11531316 |
| de novo synthesis of rna by the dengue virus rna-dependent rna polymerase exhibits temperature dependence at the initiation but not elongation phase. | replication of positive strand flaviviruses is mediated by the viral rna-dependent rna polymerases (rdrp). to study replication of dengue virus (den), a flavivirus family member, an in vitro rdrp assay was established using cytoplasmic extracts of den-infected mosquito cells and viral subgenomic rna templates containing 5'- and 3'-terminal regions (trs). evidence supported that an interaction between the trs containing conserved stem-loop, cyclization motifs, and pseudoknot structural elements i ... | 2001 | 11546770 |
| nucleotide sequencing and serological evidence that the recently recognized deer tick virus is a genotype of powassan virus. | deer tick virus (dtv) is a recently recognized north american virus isolated from ixodes dammini ticks. nucleotide sequencing of fragments of structural and non-structural protein genes suggested that this virus was most closely related to the tick-borne flavivirus powassan (pow), which causes potentially fatal encephalitis in humans. to determine whether dtv represents a new and distinct member of the flavivirus genus of the family flaviviridae, we sequenced the structural protein genes and 5' ... | 2001 | 11551648 |
| dengue fever in pregnancy: a case report. | background: dengue, a mosquito-borne flavivirus infection, is endemic in southeast asia. currently, the incidence has been increasing among adults. case presentation: a 26-year-old thai woman, g1p0 31 weeks pregnancy, presented with epigastric pain for 1 day. she also had a high-grade fever for 4 days. the physical examination, complete blood counts as well as serology confirmed dengue fever. the patient was under conservative treatment despite severe thrombocytopenia. she was well at the 3rd da ... | 2001 | 11747474 |
| construction, characterization and immunogenicity of recombinant yellow fever 17d-dengue type 2 viruses. | chimeric yellow fever (yf)-dengue type 2 (den 2) viruses were constructed by replacing the premembrane (prm) and envelope (e) genes of yf 17d virus with those from den 2 virus strains of south-east asian genotype. whereas viable chimeric viruses were successfully recovered when the yf 17d c gene and the den 2 prm gene were fused at the signalase cleavage site, no virus could be rescued from the constructions fused at the viral protease cleavage site. unlike yf virus that replicated in all the ce ... | 2001 | 11551641 |
| complete coding sequence of the alkhurma virus, a tick-borne flavivirus causing severe hemorrhagic fever in humans in saudi arabia. | to date, tick-borne flaviviruses responsible for hemorrhagic fever in humans have been isolated in siberia (omsk hemorrhagic fever virus), india (kyasanur forest disease virus, kfdv), and in saudi arabia (alkhurma virus, alkv). prior to this study, only partial coding sequences of these severe pathogens had been determined. we report here the complete coding sequence of alk virus, which was determined to be 10,248 nucleotides (nt) long, and to encode a single 3,416 amino acid polyprotein. indepe ... | 2001 | 11554750 |
| mutagenesis of the dengue virus type 2 ns3 protein within and outside helicase motifs: effects on enzyme activity and virus replication. | the protein ns3 of dengue virus type 2 (den-2) is the second largest nonstructural protein specified by the virus and is known to possess multiple enzymatic activities, including a serine proteinase located in the n-terminal region and an ntpase-helicase in the remaining 70% of the protein. the latter region has seven conserved helicase motifs found in all members of the family flaviviridae. den-2 ns3 lacking the proteinase region was synthesized as a fusion protein with glutathione s-transferas ... | 2001 | 11559795 |
| transcriptional regulation of major histocompatibility complex class i by flavivirus west nile is dependent on nf-kappab activation. | infection by the flavivirus west nile (wnv) is associated with a virus-specific increase of major histocompatibility complex class i (mhc-i) molecules on the cell surface of diploid vertebrate cells. the increased mhc-i cell surface expression is functional and is associated with increased susceptibility to secondary wnv-immune and alloimmune cytotoxic t cells. wnv-induced up-regulation of cell surface mhc-i expression is associated with nf-kappab activation and increased transcription of mhc-i ... | 2001 | 11574908 |
| mutations in the ns3 gene and 3'-ncr of japanese encephalitis virus isolated from an unconventional ecosystem and implications for natural attenuation of the virus. | the t1p1 strain of japanese encephalitis (je) virus was recently isolated from paddy-free liu-chiu islet in which natural je antibody has been prevalent. in mouse neuroblastoma-derived neuro-2a cells, t1p1 appeared significantly lower in virus productivity than another local isolate, ch1392. it implied that this new isolate possesses a characteristic viral replication pattern other than that of ch1392. t1p1 has also shown lower neurovirulence, which was reflected by a significantly higher ld(50) ... | 2001 | 11601924 |
| isolation and characterization of noncytopathic pestivirus mutants reveals a role for nonstructural protein ns4b in viral cytopathogenicity. | isolates of bovine viral diarrhea virus (bvdv), the prototype pestivirus, are divided into cytopathic (cp) and noncytopathic (ncp) biotypes according to their effect on cultured cells. the cp viruses also differ from ncp viruses by the production of viral nonstructural protein ns3. however, the mechanism by which cp viruses induce cytopathic effect in cell culture remains unknown. here we used a genetic approach to isolate ncp variants that arose from a cp virus at low frequency. a bicistronic b ... | 2001 | 11602707 |
| assembly and maturation of the flavivirus kunjin virus appear to occur in the rough endoplasmic reticulum and along the secretory pathway, respectively. | the intracellular assembly site for flaviviruses in currently not known but is presumed to be located within the lumen of the rough endoplasmic reticulum (rer). building on previous studies involving immunofluorescence (if) and cryoimmunoelectron microscopy of kunjin virus (kun)-infected cells, we sought to identify the steps involved in the assembly and maturation of kun. thus, using antibodies directed against envelope protein e in if analysis, we found the accumulation of e within regions coi ... | 2001 | 11602720 |
| gb virus-c infection in patients infected with the human immunodeficiency virus. | hepatitis virus infections are frequent in patients suffering from hiv infection due to similar transmission routes of these viruses. in addition, hepatitis virus infections lead to impaired survival in hiv positive patients. the recently discovered flavivirus gb virus c (alias hepatitis g virus) was initially believed to be another hepatitis virus. while there is still some minor discussion whether gb virus c (gbv-c) plays a role in fulminant hepatic failure, there is no evidence that this viru ... | 2001 | 11672817 |
| activity of recombinant dengue 2 virus ns3 protease in the presence of a truncated ns2b co-factor, small peptide substrates, and inhibitors. | recombinant forms of the dengue 2 virus ns3 protease linked to a 40-residue co-factor, corresponding to part of ns2b, have been expressed in escherichia coli and shown to be active against para-nitroanilide substrates comprising the p6-p1 residues of four substrate cleavage sequences. the enzyme is inactive alone or after the addition of a putative 13-residue co-factor peptide but is active when fused to the 40-residue co-factor, by either a cleavable or a noncleavable glycine linker. the ns4b/n ... | 2001 | 11581268 |
| immunization of mice against west nile virus with recombinant envelope protein. | west nile (wn) virus is a mosquito-borne flavivirus that emerged in the united states in 1999 and can cause fatal encephalitis. envelope (e) protein cdna from a wn virus isolate recovered from culex pipiens in connecticut was expressed in escherichia coli. the recombinant e protein was purified and used as ag in immunoblot assays and immunization experiments. patients with wn virus infection had abs that recognized the recombinant e protein. c3h/hen mice immunized with e protein developed e prot ... | 2001 | 11673542 |
| a novel mechanism to explain protein abnormalities in schizophrenia based on the flavivirus resistance gene. | the geographical distribution of schizophrenia was previously shown to correlate with the global distribution of tick-borne flaviviruses. the correlation suggests a natural resistance gene to flaviviruses could be involved in schizophrenia. the flavivirus resistance gene, flv, a gene found in wild mice and certain in-bred strains, confers resistance to flaviviruses through the interaction of cellular proteins with the flaviviral 3' untranslated regions (utrs). although the sequence and product o ... | 2001 | 11673799 |
| a 'minimal' approach in design of flavivirus infectious dna. | the 'infectious dna' approach, which is based on in vivo transcription of (+)rna virus genome cdna cassettes from eukaryotic promoters in transfected cells, became a popular alternative to the classical scheme in the infectious clone methodology. its use, however, is often limited by the instability of plasmids due to a transcriptional activity of eukaryotic promoters in escherichia coli resulting in synthesis of products toxic for the bacterial host. using a highly unstable representative infec ... | 2001 | 11682130 |
| experimental infections of pigs with japanese encephalitis virus and closely related australian flaviviruses. | the flavivirus japanese encephalitis (je) virus has recently emerged in the australasian region. to investigate the involvement of infections with related enzootic flaviviruses, namely murray valley encephalitis (mve) virus and kunjin (kun) virus, on immunity of pigs to je virus and to provide a basis for interpretation of serologic data, experimental infections were conducted with combinations of these viruses. antibody responses to primary and secondary infections were evaluated using panels o ... | 2001 | 11693888 |
| genomic sequencing of deer tick virus and phylogeny of powassan-related viruses of north america. | powassan (pow) virus is responsible for central nervous system infection in humans in north america and the eastern parts of russia. recently, a new flavivirus, deer tick (dt) virus, related to pow virus was isolated in the united states, but neither its pathogenic potential in human nor the taxonomic relationship with pow virus has been elucidated. in this study, we obtained the near-full-length genomic sequence of the dt virus and complete sequences of 3 genomic regions of 15 strains of pow-re ... | 2001 | 11716135 |
| infectious cdna clone of attenuated langat tick-borne flavivirus (strain e5) and a 3' deletion mutant constructed from it exhibit decreased neuroinvasiveness in immunodeficient mice. | forty-five years ago a naturally attenuated tick-borne flavivirus, langat (lgt) strain tp21, was recovered from ticks in malaysia. subsequently, it was tested as a live attenuated vaccine for virulent tick-borne encephalitis viruses. in a large clinical trial its attenuation was confirmed but there was evidence of a low level of residual virulence. thirty-five years ago further attenuation of lgt tp21 was achieved by multiple passages in eggs to yield mutant e5. to study the genetic determinants ... | 2001 | 11289811 |
| [primary infection with west-nile virus]. | the recent outbreak of an epidemic of west-nile fever in new-york revealed this virus' responsibility in some cases of fatal encephalitis. however the clinical manifestations of the infection may be mild as in the case reported herein. | 2001 | 11427804 |
| the fusion glycoprotein shell of semliki forest virus: an icosahedral assembly primed for fusogenic activation at endosomal ph. | semliki forest virus (sfv) has been extensively studied as a model for analyzing entry of enveloped viruses into target cells. here we describe the trace of the polypeptide chain of the sfv fusion glycoprotein, e1, derived from an electron density map at 3.5 a resolution and describe its interactions at the surface of the virus. e1 is unexpectedly similar to the flavivirus envelope protein, with three structural domains disposed in the same primary sequence arrangement. these results introduce a ... | 2001 | 11301009 |
| safety and immunogenicity of attenuated dengue virus vaccines (aventis pasteur) in human volunteers. | a randomized, controlled, double-blinded study was conducted to determine safety and immunogenicity of five live attenuated dengue vaccines produced by aventis pasteur (avp). the study was completed with 40 flavivirus non-immune volunteers: five recipients of each monovalent (dengue-1, dengue-2, dengue-3, or dengue-4) vaccine, ten recipients of tetravalent (dengue-1, dengue-2, dengue-3, and dengue-4) vaccine, and ten recipients of vaccine vehicle alone. all vaccines were administered in a single ... | 2001 | 11312014 |
| coupling between replication and packaging of flavivirus rna: evidence derived from the use of dna-based full-length cdna clones of kunjin virus. | in order to study whether flavivirus rna packaging is dependent on rna replication, we generated two dna-based kunjin virus constructs, pkun1 and pkun1dgdd, allowing continuous production of replicating (wild-type) and nonreplicating (with a deletion of the ns5 gene rna-polymerase motif gdd) full-length kunjin virus rnas, respectively, via nuclear transcription by cellular rna polymerase ii. as expected, transfection of pkun1 plasmid dna into bhk cells resulted in the recovery of secreted infect ... | 2001 | 11312333 |
| purification and characterization of west nile virus nucleoside triphosphatase (ntpase)/helicase: evidence for dissociation of the ntpase and helicase activities of the enzyme. | the nucleoside triphosphatase (ntpase)/helicase associated with nonstructural protein 3 of west nile (wn) virus was purified from cell culture medium harvested from virus-infected vero cells. the purification procedure included sequential chromatography on superdex-200 and reactive red 120 columns, followed by a concentration step on an ultrogel hydroxyapatite column. the nature of the purified protein was confirmed by immunoblot analysis using a wn virus-positive antiserum, determination of its ... | 2001 | 11238848 |
| a personal account of the role of peptide research in drug discovery: the case of hepatitis c. | although peptides themselves are not usually the end products of a drug discovery effort, peptide research often plays a key role in many aspects of this process. this will be illustrated by reviewing the experience of peptide research carried out at irbm in the course of our study of hepatitis c virus (hcv). the target of our work is the ns3/4a protease, which is essential for maturation of the viral polyprotein. after a thorough examination of its substrate specificity we fine-tuned several su ... | 2001 | 11245202 |
| an infectious clone of the west nile flavivirus. | west nile (wn) virus is the most widespread among flaviviruses, but until recently it was not known on the american continent. we describe here design of a subgenomic replicon, as well as a full-length infectious clone of the lineage ii wn strain, which appeared surprisingly stable compared to other flavivirus infectious clones. this infectious clone was used to investigate effects of 5'- and 3'-nonrelated sequences on virus replication and infectivity of synthetic rna. while a long nonrelated s ... | 2001 | 11277701 |
| detection and isolation of a flavivirus-like agent from a leopard tortoise (geochelone paradalis) in the united kingdom. | 2001 | 11338718 |