| nuclear localization of flavivirus rna synthesis in infected cells. | flaviviral replication is believed to be exclusively cytoplasmic, occurring within virus-induced membrane-bound replication complexes in the host cytoplasm. here we show that a significant proportion (20%) of the total rna-dependent rna polymerase (rdrp) activity from cells infected with west nile virus, japanese encephalitis virus (jev), and dengue virus is resident within the nucleus. consistent with this, the major replicase proteins ns3 and ns5 of jev also localized within the nucleus. ns5 w ... | 2006 | 16699025 |
| genetic characterization of st. louis encephalitis virus isolated from human in são paulo, brazil. | the molecular characterization of sph253157, a new strain of st. louis encephalitis virus (slev), isolated in 2004 from the first case of human infection recognized in the state of são paulo, brazil, is reported. the patient, presenting a febrile illness without neurological involvement, was hospitalized as a probable case of dengue fever. genomic rna was isolated from the supernatant of c6/36 cells infected with acute phase-serum specimen of the patient and the envelope gene was amplified by re ... | 2006 | 16699711 |
| production and characterization of vaccines based on flaviviruses defective in replication. | to develop new vaccine candidates for flavivirus infections, we have engineered two flaviviruses, yellow fever virus (yfv) and west nile virus (wnv), that are deficient in replication. these defective pseudoinfectious viruses (pivs) lack a functional copy of the capsid (c) gene in their genomes and are incapable of causing spreading infection upon infection of cells both in vivo and in vitro. however, they produce extracellular e protein in form of secreted subviral particles (svps) that are kno ... | 2006 | 16712897 |
| re: natural infection with japanese encephalitis virus among inhabitants of japan: a nationwide survey of antibodies against nonstructural 1 protein. | investigations to assess episodes of any natural japanese encephalitis (je) infection following prior immunizations with je inactivated vaccine in japan are commendable. employing differential production of nonstructural 1 protein ns1, during a natural infection and not by inactivated je vaccine [konishi e, shoda m, yamamoto s, arai s, tanaka-taya k, okabe n. natural infection with japanese encephalitis virus among inhabitants of japan: a nationwide survey of antibodies against nonstructural 1 p ... | 2006 | 16713036 |
| [tick-borne encephalitis (tbe) with special emphasis on infection in horses]. | the tick-borne encephalitis (tbe), also known as early summer meningo-encephalitis, is a geographically limited virus infection transmitted mainly by ticks. the importance of tbe is largely underestimated. the causative agent tbe-virus (tbev) is grouped into the genus flavivirus of the virus family flaviviridae. clinical disease including fatal outcomes has been described for men and dogs. with regard to horses only a limited number of case reports is available. in a study performed at the insti ... | 2006 | 16716050 |
| [abundance indices of larvae and pupae of aedes aegypti (diptera: culicidae) in córdoba city]. | in 1995, aedes aegypti, vector of the flavivirus dengue and yellow fever, reached the province. therefore, it is necessary to quantify the vector abundance in order to determine the level of risk and to evaluate the prevention and control actions implemented. | 2003 | 16724440 |
| the 3' untranslated region of tick-borne flaviviruses originated by the duplication of long repeat sequences within the open reading frame. | comparative alignment of the 3'untranslated regions (3'utrs) of tick-borne flaviviruses has previously revealed short direct repeat sequences about 25-70 nucleotides long [gritsun, t.s., venugopal, k., zanotto, p.m., mikhailov, m.v., sall, a.a., holmes, e.c., polkinghorne, i., frolova, t.v., pogodina, v.v., lashkevich, v.a., gould, e.a., 1997. complete sequence of two tick-borne flaviviruses isolated from siberia and the uk: analysis and significance of the 5' and 3'-utrs. virus res. 49 (1) 27-3 ... | 2006 | 16730048 |
| blocking of interferon-induced jak-stat signaling by japanese encephalitis virus ns5 through a protein tyrosine phosphatase-mediated mechanism. | japanese encephalitis virus (jev), a mosquito-borne flavivirus that causes severe human disease, has been shown to block the interferon (ifn)-induced janus kinase signal transducer and activation of transcription (jak-stat) signaling cascade by preventing tyk2 tyrosine phosphorylation and stat activation. in this study, we demonstrate that expression of the jev nonstructural protein ns5 readily blocked ifn-stimulated jak-stat signaling events such as stat1 nuclear translocation and tyrosine phos ... | 2006 | 16731929 |
| nmr solution structure and backbone dynamics of domain iii of the e protein of tick-borne langat flavivirus suggests a potential site for molecular recognition. | flaviviruses cause many human diseases, including dengue fever, yellow fever, west nile viral encephalitis, and hemorrhagic fevers, and are transmitted to their vertebrate hosts by infected mosquitoes and ticks. domain iii of the envelope protein (e-d3) is considered to be the primary viral determinant involved in the virus-host-cell receptor interaction, and thus represents an excellent target for antiviral drug development. langat (lgt) virus is a naturally attenuated bsl-2 tbe virus and is a ... | 2006 | 16731969 |
| evaluation of potential west nile virus vectors in volgograd region, russia, 2003 (diptera: culicidae): species composition, bloodmeal host utilization, and virus infection rates of mosquitoes. | potential west nile virus (family flaviviridae, genus flavivirus, wnv) vectors were assessed during 2003 at indoor and outdoor collection sites in urban volgograd, russia, and in three nearby towns and surrounding rural areas. in total, 9,182 female mosquitoes comprising 13 species in six genera were collected. relative abundance and bloodmeal host utilization differed temporarily and spatially. during june and july in volgograd, aedes vexans (meigen) (85.4%) and culex p. pipiens l. (7.6%) were ... | 2006 | 16739415 |
| survey of aedes triseriatus (diptera: culicidae) for lacrosse encephalitis virus and west nile virus in lorain county, ohio. | from june through september 2003, we conducted a survey of female aedes triseriatus (say) for infection with la crosse encephalitis virus (family bunyaviridae, genus orthobunyavirus, lacv) and west nile virus (family flaviviridae, genus flavivirus, wnv) at three locations in lorain county, ohio. to determine infection rate and seasonal variation of both viruses in the ae. triseriatus population, ae. triseriatus were collected weekly by using gravid traps and co2-baited cdc light traps and tested ... | 2006 | 16739420 |
| emergence of west nile virus in mosquito (diptera: culicidae) communities of the new mexico rio grande valley. | the first appearances of west nile virus (family flaviviridae, genus flavivirus, wnv) in new mexico were reported in late summer to early fall 2002. several dead birds tested positive for wnv, and 78 equine cases were confirmed. all mosquito pools tested (n = 268) were negative. a statewide surveillance program was launched in may 2003 to study the emergence and spread of this new arbovirus in mosquitoes from the rio grande valley. mosquitoes were trapped at 32 sites along a 750-km stretch of th ... | 2006 | 16739421 |
| the acre project: the epidemiology of malaria and arthropod-borne virus infections in a rural amazonian population. | the authors describe the baseline malaria prevalence and arbovirus seroprevalence among 467 subjects in an ongoing cohort study in rural amazonia. most subjects (72.2%) reported one or more previous episodes of malaria, and 15.6% had been hospitalized for malaria, but only 3.6% of individuals five years or older had malaria parasites detected by microscopy (10 with plasmodium vivax and 4 with p. falciparum). antibodies to alphavirus, orthobunyavirus, and/or flavivirus were detected by hemaggluti ... | 2006 | 16751971 |
| [infections caused by west nile virus]. | west nile virus (wnv) is a flavivirus related to tick-borne encephalitis virus endemic in northeast of poland. wnv circulates among wild birds, transmitted by wide range of haematophagous arthropods. several mosquito species, especially culex spp., can transmit wnv to humans. wnv is responsible for a broad range of clinical symptoms, from asymptomatic infection to severe encephalitis and polio-like myelitis. elderly persons are at especially high risk of death and severe neurological complicatio ... | 2006 | 16758745 |
| novel approach to analyzing rna aptamer-protein interactions: toward further applications of aptamers. | surface plasmon-resonance analysis using a biacore biosensor is a powerful tool for the detailed study of biomolecular interactions. the authors examined the methods of immobilizing proteins on the surface of nta, sa, and cm5 sensor chips to study rna aptamer-protein interactions. rna aptamers and their deletion variants were loaded onto a protein-immobilized sensor chip, and their binding affinities were analyzed. immobilizing the protein on a cm5 sensor chip via an anti-his-tag antibody was th ... | 2006 | 16760364 |
| impact of education on knowledge, agricultural practices, and community actions for mosquito control and mosquito-borne disease prevention in rice ecosystems in sri lanka. | mosquito-borne diseases are a major public health threat in sri lanka. a 20-week pilot education program to improve community knowledge and mosquito control with participatory and non-chemical approaches was developed, implemented, and evaluated using pre-educational and post-educational surveys in two intervention and two comparison villages. correlates of baseline knowledge were sex, number of family members, ratio of family members with malaria history, school education level, and availabilit ... | 2006 | 16760516 |
| seroprevalence and distribution of flaviviridae, togaviridae, and bunyaviridae arboviral infections in rural cameroonian adults. | arboviruses from the families flaviviridae, togaviridae, and bunyaviridae are suspected to cause widespread morbidity in sub-saharan african populations, but little research been done to document the burden and distribution of these pathogens. we tested serum samples from 256 cameroonian adults from nine rural villages for the presence of dengue-2 (den-2), west nile (wn), yellow fever (yf), chikungunya (chik), o'nyong-nyong (onn), sindbis (sin), and tahyna (tah) infection using standard plaque-r ... | 2006 | 16760524 |
| analysis of the domain interactions between the protease and helicase of ns3 in dengue and hepatitis c virus. | flaviviridae non-structural 3 protein (ns3) is a multifunctional enzyme, composed by a protease domain (ns3pro) and an rna helicase domain (ns3hel). the activities present in ns3 have proved to be critical for viral replication. the replicative cycle of flaviviridae requires coordinated regulation of all the activities present in the full-length ns3 protein, however, the exact nature of these interactions remains unclear. the present work aimed to determine common structural features between ns3 ... | 2007 | 16762573 |
| structure-based mutational analysis of the ns3 helicase from dengue virus. | we performed a mutational analysis of the ns3 helicase of dengue virus to test insights gleaned from its crystal structure and identified four residues in the full-length protein that severely impaired either its rtpase and atpase (arg-457-458, arg-460, arg-463) or helicase (ile-365, arg-376) activity. alanine substitution of lys-396, which is located at the surface of domain ii, drastically reduced all three enzymatic activities. our study points to a pocket at the surface of domain ii that may ... | 2006 | 16775356 |
| [west nile virus and its vectors]. | there are more than five hundred known arthropod-borne viruses (arboviruses) all around the world and approximately hundred of them may cause disease in humans. during the past 20 years there has been a dramatic resurgence or emergence of epidemic arboviral diseases affecting both humans and domestic animals. many factors play important roles in the emergence of arboviral diseases like yellow fever, dengue, west nile encephalitis, and of other diseases such as malaria and leishmaniasis in countr ... | 2006 | 16775967 |
| artificial receptors in serologic tests for the early diagnosis of dengue virus infection. | because of the range and nonspecificity of clinical presentations of dengue virus infections, we felt there was a need to create diagnostic tests. we used artificial receptors for the virus to develop serologic assays to detect dengue virus infection. | 2006 | 16777919 |
| inhibition of japanese encephalitis virus ns1 protein expression in cell by small interfering rnas. | japanese encephalitis virus (jev), a serious mosquitoborne flavivirus, causes an acute infection of the central system resulting in encephalitis of humans and many kinds of animals. a high proportion of the survivors exhibit neurogical and psychiatric sequelae. ns1 is one of important non-structural proteins, which was found to be associated with viral rna replication. to inhibit ns1 expression, four small interfering rnas (sirnas) expression plasmids (ps-ns1a, ps-ns1b, ps-ns1c and ps-ns1d) were ... | 2006 | 16791421 |
| syndromic surveillance in the netherlands for the early detection of west nile virus epidemics. | west nile virus (wnv) is an arthropod-borne flavivirus that is endemic in africa, europe, and eastern asia. the recent introduction and rapid dissemination of the virus in the united states as well as an increase in wnv outbreaks in europe, has raised concerns for its spread in europe. a surveillance system was developed to allow timely detection of an introduction of wnv infections in the netherlands. this program focuses on cases presenting with neurological disease and includes the monitoring ... | 2006 | 16796513 |
| tick-borne encephalitis in eastern france. | each y a few cases of tbe infection are described in alsace, france which lies at the occidental limit of the endemic zone of tick-borne encephalitis (tbe). hence we carried out a retrospective epidemiological and clinical study of tbe infection in alsace. data were collected from serological results sent to the institut de virologie (université louis pasteur) in strasbourg. all samples positive for specific igm against tbe were retained. the physician in charge of each patient was asked to prov ... | 2006 | 16798704 |
| pkr and rnase l contribute to protection against lethal west nile virus infection by controlling early viral spread in the periphery and replication in neurons. | west nile virus (wnv) is a neurotropic, mosquito-borne flavivirus that can cause lethal meningoencephalitis. type i interferon (ifn) plays a critical role in controlling wnv replication, spread, and tropism. in this study, we begin to examine the effector mechanisms by which type i ifn inhibits wnv infection. mice lacking both the interferon-induced, double-stranded-rna-activated protein kinase (pkr) and the endoribonuclease of the 2',5'-oligoadenylate synthetase-rnase l system (pkr(-/-) x rl(-/ ... | 2006 | 16809306 |
| a preliminary neuropathological study of japanese encephalitis in humans and a mouse model. | japanese encephalitis virus is a mosquito-borne flavivirus that causes approximately 10000 deaths annually in asia. after a brief viraemia, the virus enters the central nervous system, but the means of crossing the blood-brain barrier is uncertain. we used routine histological staining, immunohistology and electron microscopy to examine brain material from four fatal human cases, and made comparisons with material from a mouse model. in human material there was oedema, perivascular inflammation, ... | 2006 | 16814333 |
| infectious complications in renal transplant recipients. | post-kidney transplant infection is the most common life-threatening complication of long-term immunosuppressive therapy. optimal immunosuppression, in which a balance is maintained between prevention of rejection and avoidance of infection, is the most challenging aspect of posttransplantation care. the study of infectious complications in immunologically compromised recipients is changing rapidly, particularly in the fields of prophylactic and preemptive strategies, molecular diagnostic method ... | 2006 | 16815233 |
| apoptosis in mosquito midgut epithelia associated with west nile virus infection. | the mosquito culex pipiens pipiens is a documented vector of west nile virus (wnv, flaviviridae, flavivirus). our laboratory colony of c. p. pipiens, however, was repeatedly refractory to experimental transmission of wnv. our goal was to identify if a cellular process was inhibiting virus infection of the midgut. we examined midguts of mosquitoes fed control and wnv-infected blood meals. three days after feeding, epithelial cells from abdominal midguts of mosquitoes fed on wnv fluoresced under a ... | 2006 | 16820968 |
| short report: the first isolation of japanese encephalitis virus from mosquitoes collected from mainland australia. | in response to an incursion of japanese encephalitis virus (jev) on cape york peninsula, australia, in 2005, 23,144 culex mosquitoes were processed for virus detection. a single isolate of jev was obtained from a pool of culex sitiens subgroup mosquitoes. this is the first reported mosquito isolate of jev from the australian mainland. | 2006 | 16837702 |
| diversity of the population of tick-borne encephalitis virus infecting ixodes ricinus ticks in an endemic area of central switzerland (canton bern). | tick-borne encephalitis virus (tbev), a member of the genus flavivirus, has a positive-strand rna genome containing a single open reading frame flanked by non-coding regions (ncrs). ixodes ricinus ticks (n = 307) were collected from vegetation in a natural tbev focus in belp, switzerland. the presence and identity of the virus were determined by nested rt-pcr followed by sequencing of the 5'-terminal region that comprises the 5' ncr and the capsid-encoding region (c). the presence of the western ... | 2006 | 16847119 |
| hsp70 functions as a negative regulator of west nile virus capsid protein through direct interaction. | west nile virus (wnv) is a member of the flavivirus family and induces febrile illness, sporadic encephalitis, and paralysis. the capsid (cp) of wnv is thought to play a role in inducing these symptoms through caspase-3- and caspase-9-dependent apoptosis. using wnvcp as bait for a yeast two-hybrid assay, we identified that hsp70 interacted with wnvcp. the interaction between hsp70 and wnvcp was further substantiated using purified proteins. deletion analysis of hsp70 indicated that wnvcp could b ... | 2006 | 16854374 |
| fusogenic peptide as diagnostic marker for detection of flaviviruses. | dengue, japanese encephalitis, west nile encephalitis, yellow fever are the common flaviviral diseases associated with high morbidity and mortality. the initial symptoms of most of the flaviviral infections are similar to each other as well as to some other viral diseases. making clinical diagnosis, therefore, becomes a challenging task for the clinician. several studies have been reported on using detection of serum antibodies against flavivirus for the diagnosis of specific flaviviral disease; ... | 2006 | 16855316 |
| dengue vaccine. | dengue is an expanding health problem. about two-fifths of the world population are at risk for acquiring dengue with 50-100 million cases of acute febrile illness yearly including about 500,000 cases of dhf/dss. no antiviral drugs active against the flavivirus exist. attempts to control mosquito vector has been largely unsuccessful. vaccination remains the most hopeful preventive measure. dengue vaccine has been in development for more than 30 years, yet none has been licensed. the fact that en ... | 2005 | 16858980 |
| expression of vector-based small interfering rna against west nile virus effectively inhibits virus replication. | rna interference is one of the effective emerging anti-viral strategies to inhibit virus infection in cells. in this study, a small interfering rna expressing vector (psilencer-ns5) targeting the ns5 gene of west nile virus (wnv) was employed to target and destroy wnv transcripts. real-time pcr revealed drastic reduction in wnv rna transcripts in psilencer-ns5-transfected vero cells. the virus infectious titre was also significantly reduced by 90% as determined by plaque assays. the resulting de ... | 2006 | 16870272 |
| preliminary characterization of (nucleoside-2'-o-)-methyltransferase crystals from meaban and yokose flaviviruses. | viral methyltranferases (mtase) are involved in the third step of the mrna-capping process, transferring a methyl group from s-adenosyl-l-methionine (sam) to the capped mrna. mtases are classified into two groups: (guanine-n7)-methyltransferases (n7mtases), which add a methyl group onto the n7 atom of guanine, and (nucleoside-2'-o-)-methyltransferases (2'omtases), which add a methyl group to a ribose hydroxyl. the mtases of two flaviviruses, meaban and yokose viruses, have been overexpressed, pu ... | 2006 | 16880552 |
| jab1 mediates cytoplasmic localization and degradation of west nile virus capsid protein. | the clinical manifestations of west nile virus (wnv), a member of the flavivirus family, include febrile illness, sporadic encephalitis, and paralysis. the capsid (cp) of wnv is thought to participate in these processes by inducing apoptosis through mitochondrial dysfunction and activation of caspase-9 and caspase-3. to further identify the molecular mechanism of the wnv capsid protein (wnvcp), yeast two-hybrid assays were employed using wnv-cp as bait. jab1, the fifth subunit of the cop9 signal ... | 2006 | 16882664 |
| a 5' rna element promotes dengue virus rna synthesis on a circular genome. | the mechanisms of rna replication of plus-strand rna viruses are still unclear. here, we identified the first promoter element for rna synthesis described in a flavivirus. using dengue virus as a model, we found that the viral rdrp discriminates the viral rna by specific recognition of a 5' element named sla. we demonstrated that rna-rna interactions between 5' and 3' end sequences of the viral genome enhance dengue virus rna synthesis only in the presence of an intact sla. we propose a novel me ... | 2006 | 16882970 |
| serotype 1-specific monoclonal antibody-based antigen capture immunoassay for detection of circulating nonstructural protein ns1: implications for early diagnosis and serotyping of dengue virus infections. | rapid diagnosis and serotyping of dengue virus (dv) infections are important for timely clinical management and epidemiological control in areas where multiple flaviviruses are endemic. however, the speed and accuracy of diagnosis must be balanced against test cost and availability, especially in developing countries. we developed a specific antigen capture enzyme-linked immunosorbent assay (elisa) for early detection and serotyping of dv serotype 1 (dv1) by using well-characterized monoclonal a ... | 2006 | 16891505 |
| parallel infection of japanese encephalitis virus and wolbachia within cells of mosquito salivary glands. | the endosymbiont wolbachia usually causes cytoplasmic incompatibility in dipteran hosts, including mosquitoes. however, some important arbovirus-transmitting mosquitoes such as aedes aegypti (l.) are not heritably infected by wolbachia. in wolbachia-harboring mosquito armigeres subalbatus coquillett, colocalization of wolbachia and inoculated japanese encephalitis virus (family flaviviridae, genus flavivirus, jev) in salivary gland (sg) cells was shown by electron microscopy. the infection rate ... | 2006 | 16892635 |
| dengue virus ns4b interacts with ns3 and dissociates it from single-stranded rna. | dengue virus, a member of the family flaviviridae of positive-strand rna viruses, has seven non-structural proteins: ns1, ns2a, ns2b, ns3, ns4a, ns4b and ns5. except for enzymic activities contained within ns3 and ns5, the roles of the other proteins in virus replication and pathogenesis are not well defined. in this study, a physical interaction between ns4b and the helicase domain of ns3 was identified by using a yeast two-hybrid assay. this interaction was further confirmed by biochemical pul ... | 2006 | 16894199 |
| the 3' untranslated regions of kamiti river virus and cell fusing agent virus originated by self-duplication. | previously, it was shown that the 3' untranslated region (3'utr) of kamiti river virus (krv) is nearly twice as long as the 3'utr of other flaviviruses (1208 nucleotides compared with 730 nucleotides for the longest 3'utr of any virus in the tick-borne encephalitis virus species). additionally, krv and the closely related cell fusing agent virus (cfav) were shown to contain two short, almost perfect repeat sequences of 67 nucleotides. however, the construction of a robust comparative nucleotide ... | 2006 | 16894200 |
| west nile virus in complex with the fab fragment of a neutralizing monoclonal antibody. | flaviviruses, such as west nile virus (wnv), are significant human pathogens. the humoral immune response plays an important role in the control of flavivirus infection and disease. the structure of wnv complexed with the fab fragment of the strongly neutralizing mab e16 was determined to 14.5-angstrom resolution with cryo-electron microscopy. e16, an antibody with therapeutic potential, binds to domain iii of the wnv envelope glycoprotein. because of steric hindrance, fab e16 binds to only 120 ... | 2006 | 16895988 |
| manifestations of west nile neuroinvasive disease. | since its introduction to north america in 1999, west nile virus, an arthropod-borne flavivirus, has become the most significant cause of epidemic encephalitis in the western hemisphere. while most human infections with the virus are asymptomatic and the majority of symptomatic persons experience febrile illness, severe neurologic manifestations, including meningitis, encephalitis, and poliomyelitis may be seen. this review summarizes the virology, epidemiology and pathogenesis of human infectio ... | 2006 | 16906589 |
| the active essential cfns3d protein complex. | the ns2b-ns3 protease complex is essential for the replication of dengue virus, which is the etiologic agent of dengue and hemorrhagic fevers, diseases that are a burden for the tropical and subtropical areas of the world. the active form of the ns3 protease linked to the 40 residues of the ns2b cofactor shows highly flexible and disordered region(s) that are responsible for its high propensity to aggregate at the concentrations necessary for nmr spectroscopy studies or for crystallization. limi ... | 2006 | 16911516 |
| west nile virus 5'-cap structure is formed by sequential guanine n-7 and ribose 2'-o methylations by nonstructural protein 5. | many flaviviruses are globally important human pathogens. their plus-strand rna genome contains a 5'-cap structure that is methylated at the guanine n-7 and the ribose 2'-oh positions of the first transcribed nucleotide, adenine (m(7)gpppam). using west nile virus (wnv), we demonstrate, for the first time, that the nonstructural protein 5 (ns5) mediates both guanine n-7 and ribose 2'-o methylations and therefore is essential for flavivirus 5'-cap formation. we show that a recombinant full-length ... | 2006 | 16912287 |
| yellow fever: a disease that has yet to be conquered. | yellow fever virus (yfv) is the prototype member of the genus flavivirus, a group of viruses that are transmitted between vertebrates by arthropod vectors. the virus is found in tropical regions of africa and south america and is transmitted to primates by mosquitoes: aedes spp. in africa and haemagogus and sabethes spp. in south america. despite the availability of an effective vaccine, yellow fever (yf) is considered a reemerging disease owing to its increased incidence in the past 25 years. m ... | 2007 | 16913829 |
| dengue virus induces expression of cxc chemokine ligand 10/ifn-gamma-inducible protein 10, which competitively inhibits viral binding to cell surface heparan sulfate. | dengue virus is an arthropod-borne flavivirus that causes a mild febrile illness, dengue fever, or a potentially fatal syndrome, dengue hemorrhagic fever/dengue shock syndrome. chemokines primarily orchestrate leukocyte recruitment to the areas of viral infection, which makes them critical mediators of immune and inflammatory responses. in the present study, we investigated the induction and function of chemokines in mice early after infection with dengue virus in vivo. we found that cxcl10/ifn- ... | 2006 | 16920957 |
| [west nile virus genotyping among wild birds belonging to ground and tree-brush bird populations on the territories of the baraba forest-steppe and kulunda steppe (2003-2004)]. | the paper gives the results of the 2003-2004 examinations of 104 wild birds belonging to land tree-brush complexes from the baraba forest-steppe and kulunda steppe for the detection and genotyping west nile virus (wnv). elisa and rt-pcr were used to show that in the forest-steppe and steppe zones of the south of western siberia, wnv circulates among both migrating and settled birds. an analysis of the nucleotide sequence of a protein e gene fragment showed the circulation of wnv genotype ia in t ... | 2006 | 16929594 |
| west nile virus immunoglobulin a (wnv iga) detection in cerebrospinal fluid in relation to wnv igg and igm reactivity. | diagnostic criteria for neurologic involvement in wnv infection include wnv igm detection in csf; however, wnv igm can persist in csf >6 months. csf iga characterizes other flavivirus infections, but wnv iga in csf has not been evaluated. wnv igm in csf correlates with igm in serum but the presence of wnv iga in csf compared to serum is unknown. | 2006 | 16939715 |
| crystal structure of west nile virus envelope glycoprotein reveals viral surface epitopes. | west nile virus, a member of the flavivirus genus, causes fever that can progress to life-threatening encephalitis. the major envelope glycoprotein, e, of these viruses mediates viral attachment and entry by membrane fusion. we have determined the crystal structure of a soluble fragment of west nile virus e. the structure adopts the same overall fold as that of the e proteins from dengue and tick-borne encephalitis viruses. the conformation of domain ii is different from that in other prefusion ... | 2006 | 16943291 |
| preliminary crystallographic characterization of an rna helicase from kunjin virus. | kunjin virus is a member of the flavivirus genus and is an australian variant of west nile virus. the c-terminal domain of the kunjin virus ns3 protein displays helicase activity. the protein is thought to separate daughter and template rna strands, assisting the initiation of replication by unwinding rna secondary structure in the 3' nontranslated region. expression, purification and preliminary crystallographic characterization of the ns3 helicase domain are reported. it is shown that kunjin v ... | 2006 | 16946468 |
| detection of seroconversion to west nile virus, usutu virus and sindbis virus in uk sentinel chickens. | we previously reported evidence of west nile virus (wnv) circulation in uk birds, probably introduced by migratory birds from overseas. we now demonstrate wnv-specific seroconversion in sentinel chickens raised on an english farm. maternal neutralizing antibodies to wnv in hatchlings declined within three weeks. during the following months, healthy chickens developed wnv neutralizing antibodies that were confirmed by immunoblotting and indirect immunofluorescence tests using wnv antigens. the pr ... | 2006 | 16952307 |
| recombination and selection in the evolution of picornaviruses and other mammalian positive-stranded rna viruses. | picornaviridae are a large virus family causing widespread, often pathogenic infections in humans and other mammals. picornaviruses are genetically and antigenically highly diverse, with evidence for complex evolutionary histories in which recombination plays a major part. to investigate the nature of recombination and selection processes underlying the evolution of serotypes within different picornavirus genera, large-scale analysis of recombination frequencies and sites, segregation by serotyp ... | 2006 | 16956935 |
| greyhound meningoencephalitis: pcr-based detection methods highlight an absence of the most likely primary inducing agents. | greyhound meningoencephalitis is currently classified as a breed-associated idiopathic central nervous system inflammatory disorder. the non-suppurative inflammatory response can be distinguished from the other breed-associated disorders based on histopathology and lesion topography, however the nature of the response primarily suggests a viral infection. in the present study pcr and rt-pcr technologies were employed on frozen cerebral tissue from confirmed cases of meningoencephalitis to target ... | 2006 | 16962261 |
| cell-specific adaptation of two flaviviruses following serial passage in mosquito cell culture. | west nile virus (wnv) is a mosquito-borne flavivirus that was introduced into the u.s. in the new york city area in 1999. despite its successful establishment and rapid spread in a naive environment, wnv has undergone limited evolution since its introduction. this evolutionary stability has been attributed to compromises made to permit alternating cycles of viral replication in vertebrate hosts and arthropod vectors. outbreaks of a close relative of wnv, st. louis encephalitis virus (slev), occu ... | 2007 | 16963095 |
| flavivirus membrane fusion. | flavivirus membrane fusion is mediated by a class ii viral fusion protein, the major envelope protein e, and the fusion process is extremely fast and efficient. understanding of the underlying mechanisms has been advanced significantly by the determination of e protein structures in their pre- and post-fusion conformations and by the elucidation of the quarternary organization of e proteins in the viral envelope. in this review, these structural data are discussed in the context of functional an ... | 2006 | 16963734 |
| role of the yellow fever virus structural protein genes in viral dissemination from the aedes aegypti mosquito midgut. | live-attenuated virus vaccines are key components in controlling arboviral diseases, but they must not disseminate in or be transmitted by mosquito vectors. although the cycles in which many mosquito-borne viruses are transmitted are well understood, the role of viral genetics in these processes has not been fully elucidated. yellow fever virus (yfv) is an important arbovirus and the prototype member of the family flaviviridae. here, yfv was used in aedes aegypti mosquitoes as a model to investi ... | 2006 | 16963758 |
| inflammatory response in human tick-borne encephalitis: analysis of postmortem brain tissue. | in central european tick-borne encephalitis (tbe) mechanisms of tissue destruction are poorly understood. to evaluate the contribution of immunological mechanisms to tissue injury, the authors immunohistochemically analyzed paraffin-embedded autoptic brain tissue of 26 human tbe cases. in the parenchymal compartment, there was a predominance of macrophages/microglia and cytotoxic t cells. in addition, it was found that granzyme b-expressing lymphocytes were in close contact with tbe-expressing n ... | 2006 | 16966222 |
| [the risk of yellow fever in travellers]. | yellow fever is a tropical virus disease characterised by high fever, jaundice, heart and kidney failure, and haemorrhagic diathesis. the causative flavivirus is endemic in parts of tropical africa and south america and is transmitted among humans and primates by mosquitoes. the chance that an unvaccinated traveller to west africa will die of yellow fever is estimated at 1:650 to 1:5000 visitors per month of stay, depending on whether an epidemic occurs. vaccination with the attenuated yellow fe ... | 2006 | 16967591 |
| clinical features of 62 imported cases of dengue fever in japan. | to describe the clinical features of dengue cases in japan, a retrospective study was conducted on 62 laboratory-confirmed japanese dengue cases presented to tokyo metropolitan komagome hospital between 1985 and 2000. age distribution was from 18 to 62 years old (mean, 31.5 years). all cases were imported from abroad and diagnosed as dengue fever. clinical manifestations included fever (100%), headache (90%), and skin rash (82%). laboratory examinations revealed leukocytopenia (71%), thrombocyto ... | 2006 | 16968923 |
| translation of the flavivirus kunjin ns3 gene in cis but not its rna sequence or secondary structure is essential for efficient rna packaging. | our previous studies using trans-complementation analysis of kunjin virus (kun) full-length cdna clones harboring in-frame deletions in the ns3 gene demonstrated the inability of these defective complemented rnas to be packaged into virus particles (w. j. liu, p. l. sedlak, n. kondratieva, and a. a. khromykh, j. virol. 76:10766-10775). in this study we aimed to establish whether this requirement for ns3 in rna packaging is determined by the secondary rna structure of the ns3 gene or by the essen ... | 2006 | 16971441 |
| homology modeling and molecular dynamics study of west nile virus ns3 protease: a molecular basis for the catalytic activity increased by the ns2b cofactor. | the west nile virus (wnv) ns3 serine protease, which plays an important role in assembly of infective virion, is an attractive target for anti-wnv drug development. cofactors ns2b and ns4a increase the catalytic activity of ns3 in dengue virus and hepatitis c virus, respectively. recent studies on the wnv-ns3 characterize the catalytically active form of ns3 by tethering the 40-residue cofactor ns2b. it is suggested that ns2b is essential for the ns3 activity in wnv, while there is no informatio ... | 2006 | 16972281 |
| cryptic properties of a cluster of dominant flavivirus cross-reactive antigenic sites. | a number of flaviviruses are important human pathogens, including yellow fever, dengue, west nile, japanese encephalitis, and tick-borne encephalitis (tbe) viruses. infection with or immunization against any of these viruses induces a subset of antibodies that are broadly flavivirus cross-reactive but do not exhibit significant cross-neutralization. nevertheless, these antibodies can efficiently bind to the major envelope protein (e), which is the main target of neutralizing and protective antib ... | 2006 | 16973559 |
| site-directed antibodies against the stem region reveal low ph-induced conformational changes of the semliki forest virus fusion protein. | the e1 envelope protein of the alphavirus semliki forest virus (sfv) is a class ii fusion protein that mediates low ph-triggered membrane fusion during virus infection. like other class i and class ii fusion proteins, during fusion e1 inserts into the target membrane and rearranges to form a trimeric hairpin structure. the postfusion structures of the alphavirus and flavivirus fusion proteins suggest that the "stem" region connecting the fusion protein domain iii to the transmembrane domain inte ... | 2006 | 16973563 |
| flavivirus infection activates the xbp1 pathway of the unfolded protein response to cope with endoplasmic reticulum stress. | the unfolded protein response (upr) is a coordinated change in gene expression triggered by perturbations in functions of the endoplasmic reticulum (er). xbp1, a key transcription factor of the upr, is activated by an ire1-mediated splicing event, which results in a frameshift and encodes a protein with transcriptional activity. here, we report that xbp1 was activated during flaviviral infection, as evidenced by xbp1 mrna splicing and protein expression, as well as induction of the downstream ge ... | 2006 | 16987981 |
| crystal structure of the west nile virus envelope glycoprotein. | the envelope glycoprotein (e) of west nile virus (wnv) undergoes a conformational rearrangement triggered by low ph that results in a class ii fusion event required for viral entry. herein we present the 3.0-a crystal structure of the ectodomain of wnv e, which reveals insights into the flavivirus life cycle. we found that wnv e adopts a three-domain architecture that is shared by the e proteins from dengue and tick-borne encephalitis viruses and forms a rod-shaped configuration similar to that ... | 2006 | 16987985 |
| polymorphisms of the gene coding for copper/zinc superoxide dismutase (sod1) in patients with japanese encephalitis. | japanese encephalitis is the commonest form of encephalitis globally. most cases develop characteristic encephalitis but some also present with flaccid paralysis. the paralysis is secondary to damage at the alpha motor neurone, the site that is also damaged in amyotrophic lateral sclerosis (als). the gene coding for superoxide dismutase 1 (sod1) is thought to be involved in als and may also be linked to susceptibility to japanese encephalitis. to investigate this possibility, polymorphisms in th ... | 2006 | 16989689 |
| preparation and immunogenic properties of a recombinant west nile subunit vaccine. | while several west nile vaccines are being developed, none are yet available for humans. in this study aimed at developing a vaccine for humans, west nile virus (wnv) envelope protein (e) and non-structural protein 1 (ns1) were produced in the drosophila s2 cell expression system. the c-terminal 20% of the e protein, which contains the membrane anchor portion, was deleted, thus allowing for efficient secretion of the truncated protein (80e) into the cell culture medium. the proteins were purifie ... | 2007 | 16996661 |
| rapid detection, serotyping and quantitation of dengue viruses by taqman real-time one-step rt-pcr. | the use of the polymerase chain reaction (pcr) in molecular diagnosis is now accepted worldwide and has become an essential tool in the research laboratory. in the laboratory, a rapid detection, serotyping and quantitation, one-step real-time rt-pcr assay was developed for dengue virus using taqman probes. in this assay, a set of forward and reverse primers were designed targeting the serotype conserved region at the ns5 gene, at the same time flanking a variable region for all four serotypes wh ... | 2006 | 17000012 |
| the location of asparagine-linked glycans on west nile virions controls their interactions with cd209 (dendritic cell-specific icam-3 grabbing nonintegrin). | mammalian cell-derived west nile virus preferentially infects cells expressing the c-type lectin cd209l (dendritic cellspecific icam-3 grabbing nonintegrin-related protein; liver- and lymph node-specific icam-3 grabbing nonintegrin) but not cells expressing cd209 (dendritic cell-specific icam-3 grabbing nonintegrin). in contrast, dengue virus infection is enhanced in cells expressing either attachment factor. the west nile virus envelope (e) protein contains a single n-linked glycosylation site ... | 2006 | 17001080 |
| interleukin-29 uses a type 1 interferon-like program to promote antiviral responses in human hepatocytes. | interleukin-28a (il-28a), il-28b and il-29 are a family of class ii cytokines that stimulate antiviral responses through a heterodimeric receptor that is distinct from the type i interferon (ifn) receptor. to better understand how this newly described family of cytokines regulates the antiviral state, we compared various cellular responses elicited by il-29 and ifn-alpha. here we show that these cytokines stimulate similar patterns of signal transducer and activator of transcription 1 (stat-1), ... | 2006 | 17006906 |
| cutaneous delivery of a live, attenuated chimeric flavivirus vaccine against japanese encephalitis (chimerivax)-je) in non-human primates. | flaviviral diseases such as yellow fever, japanese encephalitis (je) and dengue hemorrhagic fever cause enormous morbidity and mortality worldwide. there is an urgent need for alternative technologies for mass vaccination against these and other diseases, particularly in the developing world. here, we administered a live attenuated, chimeric je vaccine (chimerivax)-je) to nonhuman primates by skin microabrasion and intradermal delivery using microneedles. both cutaneous delivery methods induced ... | 2005 | 17012854 |
| the four serotypes of dengue recognize the same putative receptors in aedes aegypti midgut and ae. albopictus cells. | dengue viruses (denv) attach to the host cell surface and subsequently enter the cell by receptor-mediated endocytosis. several primary and low affinity co-receptors for this flavivirus have been identified. however, the presence of these binding molecules on the cell surface does not necessarily render the cell susceptible to infection. determination of which of them serve as bona fide receptors for this virus in the vector may be relevant to treating denv infection and in designing control str ... | 2006 | 17014723 |
| recent emergence of insensitive acetylcholinesterase in chinese populations of the mosquito culex pipiens (diptera: culicidae). | organophosphate/carbamate target resistance has emerged in culex pipiens l. (diptera: culicidae), the vector of wuchereria bancrofti and west nile virus (family flaviviridae, genus flavivirus) in china. the insensitive acetylcholinesterase was detected in only one of 20 samples collected on a north-to-south transect. according to previous findings, a unique mutation, g119s in the ace-1 gene, explained this high insensitivity. phylogenetic analysis indicates that the mutation g119s recently detec ... | 2006 | 17017223 |
| horse-, bird-, and human-seeking behavior and seasonal abundance of mosquitoes in a west nile virus focus of southern france. | after 35 yr of disease absence, west nile virus (family flaviviridae, genus flavivirus, wnv) circulation has been regularly detected in the camargue region (southern france) since 2000. wnv was isolated from culex modestus ficalbi, which was considered the main vector in southern france after horse outbreaks in the 1960s. recent wnv transmissions outside of the cx. modestus distribution suggested the existence of other vectors. to study potential wnv vectors, horse- and bird-baited traps and hum ... | 2006 | 17017231 |
| the potential of aedes triseriatus (diptera: culicidae) as an enzootic vector of west nile virus. | the susceptibility of aedes triseriatus (say) (diptera: culicidae) to low levels of west nile virus (family flaviviridae, genus flavivirus, wnv) was determined and compared with that of culex pipiens l. to assess the likelihood of its participation in an enzootic cycle involving mammals. ae. triseriatus and cx. pipiens were exposed to wnv by feeding on baby chickens with wnv serum titers ranging from 10(4.1 +/- 0.1) to 10(8.6 +/- 0.1) plaque-forming units (pfu)/ml and from 10(4.1 +/- 0.1) to 10( ... | 2006 | 17017235 |
| detection of west nile virus rna in pools of three species of ceratopogonids (diptera: ceratopogonidae) collected in louisiana. | light traps were used to collect ceratopogonids in east baton rouge parish, louisiana. in total, 46,496 ceratopogonids were sorted from 4,968 light trap collections from 20 november 2002 through 25 november 2004. two hundred and nine pools containing specimens of 18 species of culicoides latreille, seven pools containing specimens of atrichopogon kieffer, and five pools containing specimens of forcipomyia meigen were tested for west nile virus (family flaviviridae, genus flavivirus, wnv) rna usi ... | 2006 | 17017242 |
| laboratory transmission of japanese encephalitis, west nile, and getah viruses by mosquitoes (diptera: culicidae) collected near camp greaves, gyeonggi province, republic of korea 2003. | we conducted experimental studies to evaluate mosquitoes captured in paju county, gyeonggi province, republic of korea, for their ability to transmit west nile virus (family flaviviridae, genus flavivirus, wnv), japanese encephalitis virus (family flaviviridae, genus flavivirus, jev), and getah virus (family togaviridae, genus alphavirus, getv) under laboratory conditions. both culex pipiens pallens coquillett and culex tritaeniorhynchus giles were highly susceptible to infection with wnv, with ... | 2006 | 17017248 |
| identification of avian- and mammalian-derived bloodmeals in aedes vexans and culiseta melanura (diptera: culicidae) and its implication for west nile virus transmission in connecticut, u.s.a. | to evaluate the host-feeding patterns of aedes vexans (meigen) and culiseta melanura (coquillett) as secondary vectors of west nile virus (family flaviviridae, genus flavivirus, wnv) in northeastern united states, we identified the source of vertebrate bloodmeals by sequencing portions of the cytochrome b gene of mitochondrial dna. analysis of polymerase chain reaction products from a total of 119 ae. vexans revealed that 92.4% of individuals acquired blood solely from mammalian and 2.5% from av ... | 2006 | 17017250 |
| chimeric japanese encephalitis virus/dengue 2 virus infectious clone: biological properties, immunogenicity and protection against dengue encephalitis in mice. | a molecular clone of japanese encephalitis virus (je virus) was derived from the je virus nakayama strain and used to produce infectious je virus in cell culture. the engineered je virus resembled the parental je virus in cell-culture properties and was related closely to other je virus strains based on nucleotide sequence analysis. the je virus clone was used as a genetic background for construction of a chimeric virus containing the structural proteins prm and e of dengue virus, serotype 2. th ... | 2006 | 17030845 |
| ngoye virus: a novel evolutionary lineage within the genus flavivirus. | by using degenerate primers deduced from conserved patterns in the flavivirus polymerase gene, a novel rna virus was discovered in rhipicephalus ticks sampled from members of the family bovidae in senegal. it was named ngoye virus (ngov) after the location from which it was isolated. viral particles could be observed by electron microscopy, but isolation in vertebrate or invertebrate cell lines or by intracerebral infection of newborn mice remained unsuccessful. this is atypical of recognized ar ... | 2006 | 17030860 |
| mutagenesis analysis of the ns2b determinants of the alkhurma virus ns2b-ns3 protease activation. | alkhurma virus (alkv) is a tick-borne class 4 flavivirus responsible for several human cases of haemorrhagic fever in saudi arabia, with no specific treatment currently available. the viral rna encodes a serine protease (ns2b-ns3), essential for virus replication in infected cells, that constitutes an attractive target for antiviral compounds. in an attempt to identify residues and motifs on ns2b that are necessary for protease activity of the alkv ns2b-ns3 complex, a series of modified ns2b-ns3 ... | 2006 | 17030861 |
| secondary structure of dengue virus type 4 3' untranslated region: impact of deletion and substitution mutations. | several studies have generated computer-based predictions of secondary structure of the 3' untranslated region (utr) of dengue virus (den); however, experimental verification of the formation of these structures in vitro is lacking. this study assessed the congruence of mfold predictions of secondary structure of the core region of the den type 4 3' utr with nuclease maps of this region. maps and predictions were largely consistent. maps supported the existence of previously predicted pseudoknot ... | 2006 | 17030863 |
| direct repeats in the 3' untranslated regions of mosquito-borne flaviviruses: possible implications for virus transmission. | direct repeats (drs) of 20-45 nucleotide conserved sequences (cs) and repeated cs (rcs), separated by non-conserved sequences up to 100 nucleotides long, were previously described in the 3' untranslated region (3'utr) of the three major mosquito-borne flavivirus (mbfv) subgroups, represented by japanese encephalitis virus, yellow fever virus and dengue virus. each subgroup exhibits a specific pattern of drs, the biological significance of which has not yet been adequately addressed. the drs were ... | 2006 | 17030864 |
| characterization of an immunodominant antigenic site on gb virus c glycoprotein e2 that is involved in cell binding. | gb virus type c (gbv-c) is a human flavivirus that may cause persistent infection, although most infected individuals clear viremia and develop antibodies to the envelope glycoprotein e2. to study gbv-c e2 antigenicity and cell binding, murine anti-e2 monoclonal antibodies (mabs) were evaluated to topologically map immunogenic sites on gbv-c e2 and for the ability to detect or block recombinant e2 binding to various cell lines. five competition groups of mabs were identified. groups i and ii did ... | 2006 | 17035329 |
| construction and mutagenesis of an artificial bicistronic tick-borne encephalitis virus genome reveals an essential function of the second transmembrane region of protein e in flavivirus assembly. | flaviviruses have a monopartite positive-stranded rna genome, which serves as the sole mrna for protein translation. cap-dependent translation produces a polyprotein precursor that is co- and posttranslationally processed by proteases to yield the final protein products. in this study, using tick-borne encephalitis virus (tbev), we constructed an artificial bicistronic flavivirus genome (tbev-bc) in which the capsid protein and the nonstructural proteins were still encoded in the cap cistron but ... | 2006 | 17035331 |
| insights to substrate binding and processing by west nile virus ns3 protease through combined modeling, protease mutagenesis, and kinetic studies. | west nile virus is becoming a widespread pathogen, infecting people on at least four continents with no effective treatment for these infections or many of their associated pathologies. a key enzyme that is essential for viral replication is the viral protease ns2b-ns3, which is highly conserved among all flaviviruses. using a combination of molecular fitting of substrates to the active site of the crystal structure of ns3, site-directed enzyme and cofactor mutagenesis, and kinetic studies on pr ... | 2006 | 17052977 |
| molecular epidemiology of west nile virus in humans. | after the introduction of west nile virus into the united states of america in 1999 followed by annual wnv epidemics during the mosquito seasons and spreading of the virus from the east (new york; 1999) to the west of the u.s. (california; 2003/2004) there appeared the question of whether a similar scenario could happen in europe, too. to be able to answer this question the german ministry of health decided to investigate the prevalence and incidence of wnv infections in german blood donors. fir ... | 2006 | 17058495 |
| the 3' untranslated region of tick-borne flaviviruses originated by the duplication of long repeat sequences within the open reading frame. | comparative alignment of the 3'untranslated regions (3'utrs) of tick-borne flaviviruses has previously revealed short direct repeat sequences about 25-70 nucleotides long [gritsun, t.s., venugopal, k., zanotto, p.m., mikhailov, m.v., sall, a.a., holmes, e.c., polkinghorne, i., frolova, t.v., pogodina, v.v., lashkevich, v.a., gould, e.a., 1997. complete sequence of two tick-borne flaviviruses isolated from siberia and the uk: analysis and significance of the 5' and 3'-utrs. virus res. 49 (1) 27-3 ... | 2006 | 17063566 |
| peptide inhibitors of west nile ns3 protease: sar study of tetrapeptide aldehyde inhibitors. | a series of inhibitors related to the benzoyl-norleucine-lysine-arginine-arginine (bz-nkrr) tetrapeptide aldehyde was synthesized. when evaluated against the west nile virus (wnv) ns3 protease, the measured ic(50) ranges from approximately 1 to 200 microm. concurrently, a modeling study using the recently published crystal structure of the west nile ns3/ns2b protease complex (pdb code 2fp7) was conducted. we found that the crystal structure is relevant in explaining the observed sar for this ser ... | 2006 | 17064076 |
| structural analysis of viral nucleocapsids by subtraction of partial projections. | the nucleocapsid of flavivirus particles does not have a recognizable capsid structure when using icosahedral averaging for cryo-electron microscopy structure determinations. the apparent absence of a definitive capsid structure could be due to a lack of synchronization of the symmetry elements of the external glycoprotein layer with those of the core or because the nucleocapsid does not have the same structure within each particle. a technique has been developed to determine the structure of th ... | 2007 | 17064936 |
| cleavage preference distinguishes the two-component ns2b-ns3 serine proteinases of dengue and west nile viruses. | regulated proteolysis of the polyprotein precursor by the ns2b-ns3 protease is required for the propagation of infectious virions. unless the structural and functional parameters of ns2b-ns3 are precisely determined, an understanding of its functional role and the design of flaviviral inhibitors will be exceedingly difficult. our objectives were to define the substrate recognition pattern of the ns2b-ns3 protease of west nile and dengue virises (wnv and dv respectively). to accomplish our goals, ... | 2007 | 17067286 |
| direct repeats in the flavivirus 3' untranslated region; a strategy for survival in the environment? | previously, direct repeats (drs) of 20-70 nucleotides were identified in the 3' untranslated regions (3'utr) of flavivirus sequences. to address their functional significance, we have manually generated a pan-flavivirus 3'utr alignment and correlated it with the corresponding predicted rna secondary structures. this approach revealed that intra-group-conserved drs evolved from six long repeated sequences (lrss) which, as approximately 200-nucleotide domains were preserved only in the genomes of ... | 2007 | 17067651 |
| genetic characterization of a new insect flavivirus isolated from culex pipiens mosquito in japan. | we found a new flavivirus that is widespread in culex pipiens and other culex mosquitoes in japan. the virus isolate, named culex flavivirus (cxfv), multiplied only in mosquito cell lines producing a moderate cytopathic effect, but did not grow in mammalian cells. the cxfv genome is single-stranded rna, 10,834 nt in length and containing a single open reading frame encoding a polyprotein of 3362 aa with 5' and 3' untranslated regions (utrs) of 91 and 657 nt, respectively. phylogenetic analyses r ... | 2007 | 17070886 |
| flavivirus activation of plasmacytoid dendritic cells delineates key elements of tlr7 signaling beyond endosomal recognition. | tlr7 senses rna in endosomal compartments. tlr7 expression and signaling have been demonstrated in plasmacytoid and myeloid dendritic cells, b cells, and t cells. the regulation of tlr7 signaling can play a crucial role in shaping the immune response to rna viruses with different cellular tropisms, and in developing adjuvants capable of promoting balanced humoral and cell-mediated immunity. we used unique characteristics of two ssrna viruses, dengue virus and influenza virus, to delineate factor ... | 2006 | 17082628 |
| gb virus b disrupts rig-i signaling by ns3/4a-mediated cleavage of the adaptor protein mavs. | understanding the mechanisms of hepatitis c virus (hcv) pathogenesis and persistence has been hampered by the lack of small, convenient animal models. gb virus b (gbv-b) is phylogenetically the closest related virus to hcv. it causes generally acute and occasionally chronic hepatitis in small primates and is used as a surrogate model for hcv. it is not known, however, whether gbv-b has evolved strategies to circumvent host innate defenses similar to those of hcv, a property that may contribute t ... | 2007 | 17093192 |
| [organization of the karshi virus strain leiv-2247 uz genome and its phylogenetic relationships with other representatives of the flavivirus genus]. | for the first time, the karshi virus complete genome sequence has been determined and analyzed in this work. the karshi virus was attributed to the tick-borne encephalitis group on the basis of phylogenetic analysis of polyprotein sequencing, as well as partial ns5 of the flavivirus genus. comprehensive analysis of the longed to its own cluster, which includes also the royal farm virus. | 2006 | 17094657 |
| lysine methylation as a routine rescue strategy for protein crystallization. | crystallization remains a critical step in x-ray structure determination. because it is not generally possible to rationally predict crystallization conditions, commercial screens have been developed which sample a wide range of crystallization space. while this approach has proved successful in many cases, a significant number of proteins fail to crystallize despite being soluble and monodispersed. it is established that chemical modification can facilitate the crystallization of otherwise intr ... | 2006 | 17098187 |
| cd8(+) t cell-mediated immune responses in west nile virus (sarafend strain) encephalitis are independent of gamma interferon. | the flavivirus west nile virus (wnv) can cause fatal encephalitis in humans and mice. it has recently been demonstrated, in an experimental model using wnv strain sarafend and c57bl/6 mice, that both virus- and immune-mediated pathology is involved in wnv encephalitis, with cd8(+) t cells being the dominant subpopulation of lymphocyte infiltrates in the brain. here, the role of activated wnv-immune cd8(+) t cells in mouse wnv encephalitis was investigated further. passive transfer of wnv-immune ... | 2006 | 17098975 |
| a gis tool to estimate west nile virus risk based on a degree-day model. | west nile virus (flaviviridae: flavivirus) is a serious infectious disease that recently spread across the north america continent. a spatial analysis tool was developed on the arcmap 9.x platform to estimate potential west nile virus activity using a spatially explicit degree-day model. the model identifies when the virus extrinsic incubation period (eip) is completed within the vector longevity during mid-summer months. the eip is treated as a threshold indicator of the potential for virus eme ... | 2007 | 17106782 |