Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| 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 |
| 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 |
| 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 |
| the relationships between west nile and kunjin viruses. | until recently, west nile (wn) and kunjin (kun) viruses were classified as distinct types in the flavivirus genus. however, genetic and antigenic studies on isolates of these two viruses indicate that the relationship between them is more complex. to better define this relationship, we performed sequence analyses on 32 isolates of kun virus and 28 isolates of wn virus from different geographic areas, including a wn isolate from the recent outbreak in new york. sequence comparisons showed that th ... | 2001 | 11585535 |
| 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 |
| 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 |
| 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 |
| 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 |
| effector cytolotic function but not ifn-gamma production in cytotoxic t cells triggered by virus-infected target cells in vitro. | cytolysis and interferon(ifn)-gamma production are two independent effector functions of activated cytotoxic t (tc) cells. we have used the tc-cell response against the flavivirus, murray valley encephalitis virus (mve), to investigate the requirements for inducing these two functions with regard to antigen-concentration and cd8 coreceptor involvement. cognate peptide-pulsed target cells triggered cytolysis by primary ex vivo mve-immune as well as in vitro peptide-restimulated splenocytes at low ... | 2001 | 11555403 |
| 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 |
| 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 |
| 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 |
| 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 ... | 2001 | 11548211 |
| infection with gb virus c and reduced mortality among hiv-infected patients. | the flavivirus gb virus c (gbv-c, also designated hepatitis g virus) was identified in a search for hepatitis viruses, but no disease is currently known to be associated with it. we investigated the relation between coinfection with gbv-c and the long-term outcome in patients infected with the human immunodeficiency virus (hiv). | 2001 | 11547740 |
| 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 |
| 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 |
| determination of the intramolecular disulfide bond arrangement and biochemical identification of the glycosylation sites of the nonstructural protein ns1 of murray valley encephalitis virus. | the 12 cysteine residues in the flavivirus ns1 protein are strictly conserved, suggesting that they form disulfide bonds that are critical for folding the protein into a functional structure. in this study, we examined the intramolecular disulfide bond arrangement of ns1 of murray valley encephalitis virus and elucidated three of the six cysteine-pairing arrangements. disulfide linkages were identified by separating tryptic-digested ns1 by reverse-phase high pressure liquid chromatography and an ... | 2001 | 11514736 |
| 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 |
| [pathogenesis of hemorrhagic fever]. | 2001 | 11496775 | |
| 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 |
| rapid elimination of gb virus c (hepatitis g virus) in the mosquito aedes aegypti. | the transmissibility of the gb virus c (hepatitis g virus; hgv), a member of the flaviviridae, by a typical flavivirus vector was investigated. female mosquitoes of the species aedes aegypti were fed with hgv-infected human blood and assayed 1, 24, 48, 72 and 96 h after the blood meal for viral rna, human glyceraldehyde-3-phosphate dehydrogenase mrna, human beta-actin dna and a. aegypti actin mrna by total nucleic acid extraction, reverse transcription and pcr. viral rna had already disappeared ... | 2001 | 11489416 |
| infection with langat flavivirus or expression of the envelope protein induces apoptotic cell death. | langat (lgt) flavivirus, derived from infectious full-length cdna clone 636, was investigated for its apoptotic activities in mouse neuroblastoma (neuro-2a) and simian kidney (vero and llc-mk(2)) cells. the hallmark of apoptosis, cleavage of cellular dna, was observed 48 h after infection of vero, llc-mk(2), and neuro-2a cells by electrophoresis analysis. apoptosis in infected cells was also confirmed by tunel assay. lgt-infected neuro-2a cells showed an increase in caspase-3-like protease (devd ... | 2001 | 11485400 |
| assessment of substrate specificity of hepatitis g virus ns3 protease by a genetic method. | the rna genome of hepatitis g virus (hgv) encodes a large polyprotein that is processed to mature proteins by viral-encoded proteases. the hgv ns3 protease is responsible for the cleavage of the hgv polyprotein at four different locations. no conserved sequence motif has been identified for the cleavage sites of the ns3 protease. to determine the substrate specificity of the ns3 protease, amino acid sequences cleaved by the ns3 protease were obtained from randomized sequence libraries by using a ... | 2001 | 11485324 |
| tick-borne langat/mosquito-borne dengue flavivirus chimera, a candidate live attenuated vaccine for protection against disease caused by members of the tick-borne encephalitis virus complex: evaluation in rhesus monkeys and in mosquitoes. | langat virus (lgt), strain tp21, a naturally avirulent tick-borne flavivirus, was used to construct a chimeric candidate virus vaccine which contained lgt genes for premembrane (prem) and envelope (e) glycoprotein and all other sequences derived from dengue type 4 virus (den4). the live virus vaccine was developed to provide resistance to the highly virulent, closely related tick-borne flaviviruses that share protective e epitopes among themselves and with lgt. toward that end the chimera, initi ... | 2001 | 11483771 |
| salicylates inhibit flavivirus replication independently of blocking nuclear factor kappa b activation. | flaviviruses comprise a positive-sense rna genome that replicates exclusively in the cytoplasm of infected cells. whether flaviviruses require an activated nuclear factor(s) to complete their life cycle and trigger apoptosis in infected cells remains elusive. flavivirus infections quickly activate nuclear factor kappa b (nf-kappab), and salicylates have been shown to inhibit nf-kappab activation. in this study, we investigated whether salicylates suppress flavivirus replication and virus-induced ... | 2001 | 11483726 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| [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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| essential role of cyclization sequences in flavivirus rna replication. | a possible role in rna replication for interactions between conserved complementary (cyclization) sequences in the 5'- and 3'-terminal regions of flavivirus rna was previously suggested but never tested in vivo. using the m-fold program for rna secondary-structure predictions, we examined for the first time the base-pairing interactions between the covalently linked 5' genomic region (first ~160 nucleotides) and the 3' untranslated region (last ~115 nucleotides) for a range of mosquito-borne fla ... | 2001 | 11413342 |
| 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 |
| 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 |
| [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 |
| 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 |
| encephalitis and retarded growth of chicks caused by sitiawan virus, a new isolate belonging to the genus flavivirus. | a new virus named sitiawan virus (sv) was isolated from sick broiler chicks in chicken embryos. the virus replicated well with cytopathogenic effect (cpe) in the chicken b-lymphocyte cell line lscc-bk3. the virus was an enveloped rna virus of approximately 41 nm in size with hemagglutinating activity (ha) to goose erythrocytes. it was cross-reactive with japanese encephalitis virus (jev), a member of flaviviruses by ha inhibition tests but not by cross-virus neutralization tests. the cdna fragme ... | 2000 | 11358004 |
| enzootic transmission of deer tick virus in new england and wisconsin sites. | to determine whether rodents that are intensely exposed to the deer tick-transmitted agents of lyme disease, human granulocytic ehrlichiosis, and human babesiosis are also exposed to deer tick virus (dtv), we assayed serum samples from white-footed mice (peromyscus leucopus) and meadow voles (microtus pennsylvanicus) in sites densely infested by deer ticks. to conduct serosurveys, we developed an enzyme-linked immunosorbent assay (elisa) and western blot assay by cloning, expressing, and purifyi ... | 2000 | 11357992 |
| distribution of dengue and japanese encephalitis among children in rural and suburban thai villages. | in the rainy season of 1989, igg and igm antibodies against dengue and japanese encephalitis viruses (measured by enzyme-linked immunoassay [elisa]) in serum from all primary-school children in two areas of central thailand were sampled in order to choose a study site for more detailed epidemiological and entomological analysis. students in three schools in the largely non-agricultural, suburban community of bang bua thong, nontaburi province were sampled in late june and july. of 1,477 children ... | 2000 | 11357991 |
| modulation of transporter associated with antigen processing (tap)-mediated peptide import into the endoplasmic reticulum by flavivirus infection. | in contrast to many other viruses that escape the cellular immune response by downregulating major histocompatibility complex (mhc) class i molecules, flavivirus infection can upregulate their cell surface expression. previously we have presented evidence that during flavivirus infection, peptide supply to the endoplasmic reticulum is increased (a. müllbacher and m. lobigs, immunity 3:207-214, 1995). here we show that during the early phase of infection with different flaviviruses, the transport ... | 2001 | 11356974 |
| adaptation of tick-borne encephalitis virus to bhk-21 cells results in the formation of multiple heparan sulfate binding sites in the envelope protein and attenuation in vivo. | propagation of the flavivirus tick-borne encephalitis virus in bhk-21 cells selected for mutations within the large surface glycoprotein e that increased the net positive charge of the protein. in the course of 16 independent experiments, 12 different protein e mutation patterns were identified. these were located in all three of the structural domains and distributed over almost the entire upper and lateral surface of protein e. the mutations resulted in the formation of local patches of predom ... | 2001 | 11356970 |
| characterisation of inter- and intra-molecular interactions of the dengue virus rna dependent rna polymerase as potential drug targets. | our research is directed towards enhancing the understanding of the molecular biology of dengue virus replication with the ultimate goal being to develop novel antiviral strategies based on preventing critical inter- or intra-molecular interactions required for the normal virus life cycle. the viral rna-dependent rna polymerase (ns5) and the viral helicase (ns3) interaction offers a possible target for inhibitors to bind and prevent replication. in this study the yeast-two hybrid system was used ... | 2001 | 11347963 |
| the influence of downstream protein-coding sequence on internal ribosome entry on hepatitis c virus and other flavivirus rnas. | some studies suggest that the hepatitis c virus (hcv) internal ribosome entry site (ires) requires downstream 5' viral polyprotein-coding sequence for efficient initiation of translation, but the role of this rna sequence in internal ribosome entry remains unresolved. we confirmed that the inclusion of viral sequence downstream of the aug initiator codon increased ires-dependent translation of a reporter rna encoding secretory alkaline phosphatase, but found that efficient translation of chloram ... | 2001 | 11345437 |
| evolution of base composition and codon usage bias in the genus flavivirus. | the extent to which base composition and codon usage vary among rna viruses, and the possible causes of this bias, is undetermined in most cases. a maximum-likelihood statistical method was used to test whether base composition and codon usage bias covary with arthropod association in the genus flavivirus, a major source of disease in humans and animals. flaviviruses are transmitted by mosquitoes, by ticks, or directly between vertebrate hosts. those viruses associated with ticks were found to h ... | 2001 | 11343134 |
| detection and isolation of a flavivirus-like agent from a leopard tortoise (geochelone paradalis) in the united kingdom. | 2001 | 11338718 | |
| comparison of flavivirus universal primer pairs and development of a rapid, highly sensitive heminested reverse transcription-pcr assay for detection of flaviviruses targeted to a conserved region of the ns5 gene sequences. | arthropod-transmitted flaviviruses are responsible for considerable morbidity and mortality, causing severe encephalitic, hemorrhagic, and febrile illnesses in humans. because there are no specific clinical symptoms for infection by a determined virus and because different arboviruses could be present in the same area, a genus diagnosis by pcr would be a useful first-line diagnostic method. the six published flavivirus genus primer pairs localized in the ns1, ns3, ns5, and 3' nc regions were eva ... | 2001 | 11326014 |
| experimental yellow fever virus infection in the golden hamster (mesocricetus auratus). i. virologic, biochemical, and immunologic studies. | this report describes the clinical laboratory findings in golden hamsters experimentally infected with yellow fever (yf) virus. an accompanying paper describes the pathologic findings. following intraperitoneal inoculation of a virulent strain of yf virus, hamsters developed a high-titered viremia (up to 109/ml) lasting 5--6 days and abnormal liver function tests. yf hemagglutination-inhibiting antibodies appeared 4 or 5 days after infection, often while viremia was still present. the mortality ... | 2001 | 11319679 |
| dengue virus specific t cell responses to live attenuated monovalent dengue-2 and tetravalent dengue vaccines. | the proliferative t cell responses to dengue vaccines were studied using the parental strains of dengue vaccines as antigens in 26 dengue immune individuals who resided in bangkok which is the endemic area of dengue infection. the magnitude of the t cell responses in subjects with flavivirus cross-reactive neutralizing antibody was much higher and the cross-reactivity was broader than in those with dengue serotype-specific neutralizing antibodies, japanese encephalitis (je) specific antibodies o ... | 2000 | 11316044 |
| 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 |
| 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 |
| phylogenetic analysis of brazilian flavivirus using nucleotide sequences of parts of ns5 gene and 3' non-coding regions. | viruses of the genus flavivirus, which are arboviruses, of the flaviviridae family, are amongst the most important agents of infectious disease in brazil, causing human infections with a high morbility and mortality. in this work, the phylogeny of 14 virus amplicon sequences that were obtained by rt-pcr with universal primers for mosquito-borne flavivirus were studied. the amplicons included a region of the flavivirus genome of 129 nucleotides at the 3' terminus of the ns5 gene and the 145 initi ... | 2001 | 11311426 |
| 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 |
| virus evolution: how does an enveloped virus make a regular structure? | 2001 | 11300997 | |
| self-replicative rna vaccines elicit protection against influenza a virus, respiratory syncytial virus, and a tickborne encephalitis virus. | in genetic vaccination, recipients are immunized with antigen-encoding nucleic acid, usually dna. this study addressed the possibility of using the recombinant alpha virus rna molecule, which replicates in the cytoplasm of transfected cells, as a novel approach for genetic vaccination. mice were immunized with recombinant semliki forest virus rna-encoding envelope proteins from one of 3 viruses: influenza a virus, a tickborne flavivirus (louping ill virus), or respiratory syncytial virus (rsv). ... | 2001 | 11294672 |
| 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 |
| isolation of japanese encephalitis virus from mosquitoes (diptera: culicidae) collected in the western province of papua new guinea, 1997-1998. | after japanese encephalitis (je) virus emerged in the torres strait in australia in 1995, investigations were initiated into the origin of the incursion. new guinea was considered the most likely source, given its proximity to islands of the torres strait. almost 400,000 adult mosquitoes were processed for virus isolation from 26 locations in the western province of papua new guinea (png) between february 1996 and february 1998, yielding three isolates of je virus. two isolates of murray valley ... | 2000 | 11289676 |
| mutational evidence for an internal fusion peptide in flavivirus envelope protein e. | the envelope protein e of the flavivirus tick-borne encephalitis (tbe) virus promotes cell entry by inducing fusion of the viral membrane with an intracellular membrane after uptake by endocytosis. this protein differs from other well-studied viral and cellular fusion proteins because of its distinct molecular architecture and apparent lack of involvement of coiled coils in the low-ph-induced structural transitions that lead to fusion. a highly conserved loop (the cd loop), which resides at the ... | 2001 | 11287576 |
| west nile virus recombinant dna vaccine protects mouse and horse from virus challenge and expresses in vitro a noninfectious recombinant antigen that can be used in enzyme-linked immunosorbent assays. | introduction of west nile (wn) virus into the united states in 1999 created major human and animal health concerns. currently, no human or veterinary vaccine is available to prevent wn viral infection, and mosquito control is the only practical strategy to combat the spread of disease. starting with a previously designed eukaryotic expression vector, we constructed a recombinant plasmid (pcbwn) that expressed the wn virus prm and e proteins. a single intramuscular injection of pcbwn dna induced ... | 2001 | 11287553 |
| prevalence of tick-borne encephalitis virus in ixodes ricinus ticks in finland. | approximately 20 cases of tick-borne encephalitis (tbe) occur annually in finland. the known endemic areas are situated mainly in the archipelago and coastal regions of finland, with highest incidence in aland islands. ixodes ricinus panels collected in 1996-1997 from two endemic areas were screened for the presence of rna. two distinct rt-pcr methods were applied, and were shown to have an approximate detection limit of 10 focus forming doses (ffd)/100 microl. one out of 20 pools (a total of 13 ... | 2001 | 11285564 |
| 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 |
| a new strategy in design of +rna virus infectious clones enabling their stable propagation in e. coli. | infectious clone methodology is a valuable tool of modern experimental virology. however, its use is often constrained by the instability of infectious clone constructs during propagation in e. coli. to circumvent this problem, we have devised a strategy that could be suitable for design of +rna virus molecular clones in general. an infectious clone is assembled as "infectious dna," and expression of problem regions present in the viral cdna is prevented during propagation in e. coli by insertio ... | 2001 | 11277699 |
| effect of naturally occurring active site mutations on hepatitis c virus ns3 protease specificity. | a comparison of the dna sequences from all available genotypes of hcv indicate that the active site residues of the ns3 protease are strictly conserved with the exception of positions 123 and 168, which border the s(4) subsite. in genotype 3, the canonic arginine and aspartic acid have been replaced with threonine and glutamine, respectively. to determine if these differences contribute to an altered specificity, we characterized single-chain ns3 proteases from strains 1a, 1b, and 3a with peptid ... | 2001 | 11276078 |
| biophysical characterization and vector-specific antagonist activity of domain iii of the tick-borne flavivirus envelope protein. | the molecular determinants responsible for flavivirus host cell binding and tissue tropism are largely unknown, although domain iii of the envelope protein has been implicated in these functions. we examined the solution properties and antagonist activity of langat virus domain iii. our results suggest that domain iii adopts a stably folded structure that can mediate binding of tick-borne flaviviruses but not mosquito-borne flaviviruses to their target cells. three clusters of phylogenetically c ... | 2001 | 11264392 |
| langat virus m protein is structurally homologous to prm. | langat (lgt) virus m protein has been generated in a recombinant system. antiserum raised against the lgt virus m protein neutralizes tick-borne encephalitis serocomplex flaviviruses but not mosquito-borne flaviviruses, indicating that the m protein is exposed on the surface of virions. the antiserum recognizes intracellular lgt virus prm/m and binds to prm and m in western blots of whole-cell lysates and purified virus, respectively. these data suggest that the prm and m proteins are structural ... | 2001 | 11264391 |
| a small region of the dengue virus-encoded rna-dependent rna polymerase, ns5, confers interaction with both the nuclear transport receptor importin-beta and the viral helicase, ns3. | the dengue virus rna-dependent rna polymerase, ns5, and the protease/helicase, ns3, are multidomain proteins that have been shown to interact both in vivo and in vitro. a hyperphosphorylated form of ns5 that does not interact with ns3 has been detected in the nuclei of virus-infected cells, presumably as the result of the action of a functional nuclear localization sequence within the interdomain region of ns5 (residues 369-405). in this study, it is shown by using the yeast two-hybrid system th ... | 2001 | 11257177 |
| production of active mammalian and viral proteases in bacterial expression systems. | 2000 | 11255667 | |
| replicon-based vectors of positive strand rna viruses. | vectors based on self-replicating rnas (replicons) of positive strand rna viruses are becoming powerful tools for gene expression in mammalian cells and for the development of novel antiviral and anticancer vaccines. a relatively small genome size and simple procedure allow rapid generation of recombinants. cytoplasmic rna amplification eliminates nuclear involvement and leads to extremely high levels of gene expression, and continuous synthesis of double stranded rna results in induction of enh ... | 2000 | 11249758 |
| 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 |
| 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 |
| antiviral cytotoxic t cells cross-reactively recognize disparate peptide determinants from related viruses but ignore more similar self- and foreign determinants. | we have investigated the reactivities of cytotoxic t (tc) cells against the two immunodominant, h-2k(k)-restricted determinants from the flavivirus: murray valley encephalitis virus (mve), mve(1785) (rehsgnei) and mve(1971) (degegrvi). the respective tc cell populations cross-reactively lysed target cells pulsed with determinants from the mve(1785)- and mve(1971)-corresponding positions of six other flaviviruses, despite low sequence homology in some cases. notably, anti-mve(1785) tc cells recog ... | 2001 | 11238625 |
| [protective activity of a bacterial plasmid, bearing the gene for the tick-borne encephalitis virus ns1 nonstructural protein]. | three intramuscular injections (50 micrograms each) with bacterial plasmid pmv45 carrying nonstructural gene of ns1 protein of tick-borne encephalitis (tbe) virus protected 88% balb/c mice from lethal challenge with the virus. antibodies to ns1 nonstructural protein were detected in the sera of vaccinated mice after the challenge. absence of antibodies to e structural protein indicated absence of manifest infectious process in mice vaccinated with plasmid and challenged with a lethal dose of tbe ... | 2001 | 11233282 |
| [genetic typing of tick-borne encephalitis virus based on an analysis of the levels of homology of a membrane protein gene fragment]. | all heretofore known genomic structures of tick-borne encephalitis (tbe) virus are analyzed. the authors prove the adequacy of using short fragment of e protein gene for characterization of philogenetic relationships between tbe strains. three main genotypes of the virus are distinguished, one corresponding to far eastern variant, one to west, and the third includes strains belonging to ural siberian and central siberian and transbaikal variants. results of genetic typing by nucleotide sequences ... | 2001 | 11233281 |
| [analysis of genetic variability of strains of tick-borne encephalitis virus by primary structure of a fragment of the membrane protein e gene]. | primary structures of gene fragments of e protein (160 n.b.) have been determined for 29 tick-borne encephalitis (tbe) strains isolated from different parts of a territory. analysis of homology of nucleotide sequences of these strains and data on 6 tbe strains published by other authors showed that they can be divided into 6 groups (genotypes) by the following gene typing criteria: strain structure within the genotypes differing by no more than 9%, differences between strains of different genoty ... | 2001 | 11233280 |
| identification of b-cell epitope of dengue virus type 1 and its application in diagnosis of patients. | using a serotype-specific monoclonal antibody (mab) of dengue virus type 1 (den-1), 15f3-1, we identified the b-cell epitope of den-1 from a random peptide library displayed on phage. fourteen immunopositive phage clones that bound specifically to mab 15f3-1 were selected. these phage-borne peptides had a consensus motif of hxyawb (a = s/t, b = k/h/r) that mimicked the sequence hkyswk, which corresponded to amino acid residues 111 to 116 of the nonstructural protein 1 (ns1) of den-1. among the f ... | 2001 | 11230414 |
| genetic variation of japanese encephalitis virus in taiwan. | a 280-nucleotide sequence from the capsid-premembrane (c/prem) gene region of 44 japanese encephalitis (je) virus strains isolated in taiwan from mosquitoes from 1983 to 1994, and 3 strains, (ling [1965], chang [1965], and hv1 [1958]) isolated from human brain were analyzed by direct sequencing of reverse transcription-polymerase chain reaction (rt-pcr) amplified products and compared with the corresponding sequences of reference strains. the overall sequence homology of the 47 isolates was > or ... | 2000 | 11220759 |
| 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 |
| west nile encephalitis. | wnv encephalitis in horses, previously reported in africa, asia, and europe, occurred for the first time in the western hemisphere in 1999. the causative agent, wnv, is a flavivirus maintained in nature by a bird-mosquito cycle. the disease in horses is manifested primarily by ataxia of variable severity. outbreaks of encephalitis may have a case fatality rate in excess of 40%, although this virus infection is inapparent in some horses. early evidence indicates that wnv has overwintered in the n ... | 2000 | 11219341 |
| west nile virus investigations in south moravia, czechland. | seven virus isolates were obtained from 11,334 mosquitoes after the 1997 morava river flooding in south moravia (czech republic): 6 strains of tahyna bunyavirus, california antigenic group (5 from aedes vexans, 1 from ae. cinereus), and 1 strain of west nile flavivirus (wnv) from culex pipiens. in 1999, one isolate of tahyna virus from ae. vexans and one isolate of wnv from cx. pipiens were recovered from a total of 14,354 mosquitoes examined in the same area, whereas no virus was detected there ... | 2000 | 11192289 |
| west nile viral encephalitis. | west nile virus (wnv) has emerged in recent years in temperate regions of europe and north america, presenting a threat to both public and animal health. the most serious manifestation of infection is fatal encephalitis in humans and horses, as well as mortality in certain domestic and wild birds. a recent development in the epizootiology of this mosquito-borne flavivirus was the occurrence of a severe outbreak in new york city and surrounding areas. during this outbreak, mortality was observed ... | 2000 | 11189714 |
| innate resistance to flavivirus infection in mice controlled by flv is nitric oxide-independent. | innate resistance to flaviviruses in mice is active in the brain where it restricts virus replication. this resistance is controlled by a single genetic locus, flv, located on mouse chromosome 5 near the locus encoding the neuronal form of nitric oxide synthase (nos1). since nitric oxide (no) has been implicated in antiviral activity, its involvement in natural resistance to flaviviruses has been hypothesized. here we present data on no production before and during flavivirus infection in both b ... | 2001 | 11172102 |
| antibody to the nonstructural protein ns1 of japanese encephalitis virus: potential application of mab-based indirect elisa to differentiate infection from vaccination. | an indirect enzyme-linked immunosorbent assay (elisa) was developed to detect and differentiate the antibody responses to japanese encephalitis (je) virus nonstructural protein ns1 between infected and vaccinated individuals. the results showed that all convalescent sera from je patients contained ns1-specific igg antibodies, while 65 and 40% of these sera showed detectable ns1-specific igm and iga antibodies, respectively. specificity analysis showed that ns1-specific igm and iga antibodies fro ... | 2001 | 11166901 |
| comparison of six different commercial igg-elisa kits for the detection of tbev-antibodies. | tick-borne encephalitis virus (tbev) is a pathogenic human flavivirus endemic in some parts of europe and asia. commercial enzyme immunoassays (eia) for the detection of igg antibodies are often used in tbev-seroprevalence studies, as well as for the confirmation of a successful vaccination against tbev. however, the detection of tbev-specific antibodies can be biased by the cross-reactivity between different flavivirus genera. | 2001 | 11166668 |
| development of dengue igm-capture enzyme-linked immunosorbent assay with higher sensitivity using monoclonal detection antibody. | an igm-capture enzyme-linked immunosorbent assay (igm-elisa) is used widely for serodiagnosis of dengue. a dengue igm-elisa with higher sensitivity has been developed. in the new elisa, anti-dengue igm antibody, which had been captured on the solid phase, was reacted with tetravalent dengue viral antigens, and detected by a flavivirus group specific monoclonal antibody, d1-4g2-4-15 (4g2). reaction of 4g2 to viral antigens was similar to that of dengue patients' igg. non-specific reaction of 4g2 ... | 2001 | 11164919 |
| 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 |
| diagnostic immunoassays for tick-borne encephalitis virus based on recombinant baculovirus protein expression. | the baculovirus expression system that utilizes autographa californica nuclear polyhedrosis virus was used to express the highly antigenic envelope protein e of a tick-borne encephalitis (tbe) complex virus, as well as a c-terminally truncated form of protein e (etr). the recombinant proteins were produced with a histidine-tag at their carboxy-terminus. protein purification by nickel agarose chromatography resulted in high concentrations of pure etr protein, but only poor yields of e protein. th ... | 2001 | 11164488 |
| solution structure and dynamics of the single-chain hepatitis c virus ns3 protease ns4a cofactor complex. | the backbone assignments, secondary structure, topology, and dynamics of the single-chain hepatitis c virus ns3 protease ns4a cofactor complex have been determined by nmr spectroscopy. residues i34 to s181 of ns3 and the central three residues of the ns4a cofactor were assigned and the secondary structure was verified for these residues. in several x-ray structures of ns4a-bound ns3 protease, residues 1 to 28 are stabilized by crystal packing, which allows for the formation of the a0 strand and ... | 2001 | 11162117 |
| [west nile virus (wnv) encephalitis]. | a disease on the come back: west nile encephalitis has been known since the thirties. it generally occurs in africa and western asia, rarely in europe. the disease has disappeared from france since 1960, but has reappeared in the united states and in israel. a severe viral infection: west nile encephalitis is caused by a flavivirus. after 2 to 15 days incubation, the patient experiences fever, headache, diffuse pain, and sometimes skin rash. disorientation, stiff neck, convulsions and paralysis ... | 2000 | 11155732 |
| 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 |
| a novel model for the study of the therapy of flavivirus infections using the modoc virus. | the murine flavivirus modoc replicates well in vero cells and appears to be as equally sensitive as both yellow fever and dengue fever virus to a selection of antiviral agents. infection of scid mice, by either the intracerebral, intraperitoneal, or intranasal route, results in 100% mortality. immunocompetent mice and hamsters proved to be susceptible to the virus only when inoculated via the intranasal or intracerebral route. animals ultimately die of (histologically proven) encephalitis with f ... | 2001 | 11145886 |
| 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 |
| 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 |