| dengue virus rna purification from human plasma: a comparison of two techniques. | dengue virus rna purification from human plasma is useful for research and clinical purposes. dengue is endemic in the espirito santo state, brazil, and it is progressively becoming a hard-to-control public health problem [1]. dengue virus types 1, 2 and 3 are currently found in brazilian territory, and recently dengue virus type 4 has been reported to enter brazilian borders. this virus spreads rapidly during epidemic outbreaks, and thousands of patients are infected annually, with an underesti ... | 2010 | 21161397 |
| acute dengue virus 2 infection in gabonese patients is associated with an early innate immune response, including strong interferon alpha production. | dengue is now a leading cause of morbidity and mortality throughout the tropics. we conducted the first ex vivo study of dengue fever (df) in african patients infected during the first gabonese dengue virus 2 (denv-2) outbreak in 2007, in order to investigate cytokine production, including the antiviral cytokine ifn-α, reported to be a potent inhibitor of denv replication in vitro. | 2010 | 21167041 |
| endurance, refuge, and reemergence of dengue virus type 2, puerto rico, 1986-2007. | to study the evolution of dengue virus (denv) serotype 2 in puerto rico, we examined the genetic composition and diversity of 160 denv-2 genomes obtained through 22 consecutive years of sampling. a clade replacement took place in 1994-1997 during a period of high incidence of autochthonous denv-2 and frequent, short-lived reintroductions of foreign denv-2. this unique clade replacement was complete just before denv-3 emerged. by temporally and geographically defining denv-2 lineages, we describe ... | 2011 | 21192856 |
| quantifying the spatial dimension of dengue virus epidemic spread within a tropical urban environment. | dengue infection spread in naive populations occurs in an explosive and widespread fashion primarily due to the absence of population herd immunity, the population dynamics and dispersal of ae. aegypti, and the movement of individuals within the urban space. knowledge on the relative contribution of such factors to the spatial dimension of dengue virus spread has been limited. in the present study we analyzed the spatio-temporal pattern of a large dengue virus-2 (denv-2) outbreak that affected t ... | 2010 | 21200419 |
| west nile virus rna not detected in urine of 40 people tested 6 years after acute west nile virus disease. | west nile virus (wnv) causes an acute infection that is usually cleared by an effective immune response after several days of viremia. however, a recent study detected wnv rna in the urine of 5 of 25 persons (20%) tested several years after their initial acute wnv disease. we evaluated an established cohort of 40 persons >6 years after initial infection with wnv. urine collected from all participants tested negative for wnv rna by reverse-transcription polymerase chain reaction and transcription ... | 2010 | 21208926 |
| successful propagation of flavivirus infectious cdnas by a novel method to reduce the cryptic bacterial promoter activity of virus genomes. | reverse genetics is a powerful tool to study single-stranded rna viruses. despite tremendous efforts having been made to improve the methodology for constructing flavivirus cdnas, the cause of toxicity of flavivirus cdnas in bacteria remains unknown. here we performed mutational analysis studies to identify escherichia coli promoter (ecp) sequences within nucleotides (nt) 1 to 3000 of the dengue virus type 2 (denv2) and japanese encephalitis virus (jev) genomes. eight and four active ecps were d ... | 2011 | 21228244 |
| letter to the editor: molecular genotyping of dengue virus types 2 and 4 from the guatemalan and honduran epidemics of 2007 using the envelope glycoprotein gene. | eight serum specimens collected from dengue patients in guatemala and honduras during the central american epidemic of 2007 were analyzed. virus identification and serotyping performed by a nested rt-pcr assay revealed two denv-1 isolates from guatemala, four denv-2 isolates, two each from guatemala and honduras, and two denv-4 isolates from honduras. viral genotyping determined by phylogenetic analysis of the complete envelope gene sequences demonstrated that the denv-2 isolates from guatemala ... | 2011 | 21234665 |
| virus role during intraepidemic increase in dengue disease severity. | dengue epidemics in cuba have repeatedly demonstrated a month-to-month increase in clinical severity during secondary infections. the dengue 2 outbreak that occurred in santiago de cuba in 1997 was accompanied by the most severe intraepidemic increase in disease severity reported to date. it was initially proposed that the appearance of neutralization escape mutants during the course of the epidemic might explain this phenomenon. recent studies have revealed that during the course of this epidem ... | 2011 | 21254883 |
| massively parallel pathogen identification using high-density microarrays. | identification of microbial pathogens in clinical specimens is still performed by phenotypic methods that are often slow and cumbersome, despite the availability of more comprehensive genotyping technologies. we present an approach based on whole-genome amplification and resequencing microarrays for unbiased pathogen detection. this 10 h process identifies a broad spectrum of bacterial and viral species and predicts antibiotic resistance and pathogenicity and virulence profiles. we successfully ... | 2008 | 21261824 |
| dengue virus type 2 recognizes the carbohydrate moiety of neutral glycosphingolipids in mammalian and mosquito cells. | dengue viruses infect cells by attaching to a surface receptor which remains unknown. the putative receptor molecules of dengue virus type 2 on the surface of mosquito (ap-61) and mammalian (llc-mk2) cell lines were investigated. the immunochemical detection and structural analysis of carbohydrates demonstrated that the neutral glycosphingolipids, l-3 (glcnacß1-3manß1-4glcß1-1'cer) in ap-61 cells, and nlc(4) cer (galß1-4glcnacß1-3galß1-4glcß1-1'cer) in llc-mk2 cells were recognized by the virus. ... | 2011 | 21265875 |
| replication of the primary dog kidney-53 dengue 2 virus vaccine candidate in aedes aegypti is modulated by a mutation in the 5' untranslated region and amino acid substitutions in nonstructural proteins 1 and 3. | previous studies have demonstrated reduced replication of the cell culture-adapted dengue-2 virus (denv-2) vaccine candidate, primary dog kidney (pdk)-53, compared with the parental denv-2 strain, 16681, in c6/36 cells. various denv-2 mutants incorporating pdk-53 substitutions singly and in combination into the 16681 genetic backbone were used to identify the genetic basis for impaired replication of the vaccine candidate in vitro in aedes aegypti cell culture (aag2 cells) as well as the reduced ... | 2011 | 21284523 |
| differential inhibition of dengue virus infection in mammalian and mosquito cells by iota-carrageenan. | the antiviral activity against dengue virus-2 (denv-2) of carrageenans reported here has shown a differential susceptibility of c6/36 ht and vero cells, taken as models of mosquito and mammalian cells, depending on the structural class of polysaccharides: all polysaccharides blocked denv-2 infection in monkey vero cells, but only iota-carrageenans were virus inhibitors in mosquito cells. however, iota-carrageenans were less effective in mosquito cells in comparison with mammalian cells with effe ... | 2011 | 21325483 |
| dengue virus infection of sk hep1 cells: inhibition of in vitro angiogenesis and altered cytomorphology by expressed viral envelope glycoprotein. | dengue virus (denv) infection of human endothelial cells has been implicated in the pathobiology of dengue hemorrhagic fever and dengue shock syndrome. however, the mechanisms by which denv infections alter the functional physiology of endothelial cells remain incompletely understood. in the present study, we examined the susceptibility of a human liver sinusoidal endothelial cell line sk hep1 to all four serotypes of denv and studied the effect of the virus on in vitro angiogenesis. all four se ... | 2011 | 21332827 |
| kinetics of plasma viremia and soluble nonstructural protein 1 concentrations in dengue: differential effects according to serotype and immune status. | we describe the magnitude and kinetics of plasma viremia and nonstructural protein 1 (sns1) levels in sequential samples from 167 children with acute dengue, enrolled early in a community study in vietnam. all children recovered fully, and only 5 required hospitalization. among those with dengue virus type 1 (denv-1), plasma viremia was significantly greater in primary (49) than secondary (44) infections and took longer to resolve. in primary denv-2 and 3 infections, viremia was significantly lo ... | 2011 | 21335562 |
| evaluation of widely used diagnostic tests to detect west nile virus infections in horses previously infected with st. louis encephalitis virus or dengue virus type 2. | primary west nile virus (wnv) infections can be diagnosed using a number of tests that detect infectious particles, nucleic acid, and specific igm and/or igg antibodies. however, serological identification of the infecting agent in secondary or subsequent flavivirus infections is problematic due to the extensive cross-reactivity of flavivirus antibodies. this is particularly difficult in the tropical americas where multiple flaviviruses cocirculate. a study of sequential flavivirus infection in ... | 2011 | 21346058 |
| amino acid changes within the e protein hinge region that affect dengue virus type 2 infectivity and fusion. | fifteen mutant dengue viruses were engineered and used to identify aas in the molecular hinge of the envelope protein that are critical to viral infection. substitutions at q52, a54, or e133 reduced infectivity in mammalian cells and altered the ph threshold of fusion. mutations at f193, g266, i270, or g281 affected viral replication in mammalian and mosquito cells, but only i270w had reduced fusion activity. t280y affected the ph threshold for fusion and reduced replication in c6/36 cells. thre ... | 2011 | 21353281 |
| designing cyclic peptide inhibitor of dengue virus ns3-ns2b protease by using molecular docking approach. | peptides are preferred for designing inhibitors because of their high activity and specificity. seven cyclopentapeptide inhibitors were designed in this study against dengue virus type 2 (den-2) ns3-ns2b protease: ckrrc, cgrrc, crgrc, crtrc, ctrrc, ckrkc and crrkc. docking analysis was performed to study the enzyme-inhibitor binding interactions. the free energy binding and estimated ki values for all the inhibitors were found to be small (within micromolar range), indicating that the inhibitors ... | 2010 | 21364826 |
| nf90 binds the dengue virus rna 3' terminus and is a positive regulator of dengue virus replication. | viral rna translation and replication are regulated by sequence and structural elements in the 5' and 3' untranslated regions (utr) and by host cell and/or viral proteins that bind them. dengue virus has a single-stranded rna genome with positive polarity, a 5' m7gpppg cap, and a conserved 3'-terminal stem loop (sl) that is linked to proposed functions in viral rna transcription and translation. mechanisms explaining the contributions of host proteins to viral rna translation and replication are ... | 2011 | 21386893 |
| dengue infection increases the locomotor activity of aedes aegypti females. | aedes aegypti is the main vector of the virus causing dengue fever, a disease that has increased dramatically in importance in recent decades, affecting many tropical and sub-tropical areas of the globe. it is known that viruses and other parasites can potentially alter vector behavior. we investigated whether infection with dengue virus modifies the behavior of aedes aegypti females with respect to their activity level. | 2011 | 21408119 |
| synthetic peptides containing b- and t-cell epitope of dengue virus-2 e domain iii provoked b- and t-cell responses. | our previous work applied a combination of bioinformatics approaches and in vitro assays to identify the dengue-2 virus (denv-2)-specific b- and t-cell epitopes. in this report, we first evaluated the antigenicity of both b- and t-cell epitopes reacting with different sera against denv-2 by elisa as well as the ability of t-cell epitope to activate cd4(+) t-cell producing ifn-? using elispot, which showed a specific reactivity between either b- or t-cell epitope and denv-2 antisera, and a signif ... | 2011 | 21419774 |
| evaluation of two molecular methods for the detection of yellow fever virus genome. | yellow fever virus (yfv), a member of the family flaviviridae, genus flavivirus is endemic to tropical areas of africa and south america and is among the arboviruses that pose a threat to public health. recent outbreaks in brazil, bolivia, and paraguay and the observation that vectors capable of transmitting yfv are presenting in urban areas underscore the urgency of improving surveillance and diagnostic methods. two novel methods (rt-hemi-nested-pcr and sybr(®) green qrt-pcr) for efficient dete ... | 2011 | 21419803 |
| n-linked glycosylation of dengue virus ns1 protein modulates secretion, cell-surface expression, hexamer stability, and interactions with human complement. | dengue virus (denv) ns1 is a versatile non-structural glycoprotein that is secreted as a hexamer, binds to the cell surface of infected and uninfected cells, and has immune evasive functions. denv ns1 displays two conserved n-linked glycans at n130 and n207. in this study, we examined the role of these two n-linked glycans on ns1 secretion, stability, and function. because some groups have reported reduced yields of infectious denv when n130 and n207 are changed, we analyzed glycosylation-defici ... | 2011 | 21429549 |
| inhibition of bovine viral diarrhea virus rna synthesis by thiosemicarbazone derived from 5,6-dimethoxy-1-indanone. | in the present work, we described the activity of the thiosemicarbazone derived from 5,6-dimethoxy-1-indanone (tsc), which we previously characterized as a new compound that inhibits bovine viral diarrhea virus (bvdv) infection. we showed that tsc acts at a point of time that coincides with the onset of viral rna synthesis and that it inhibits the activity of bvdv replication complexes (rcs). moreover, we have selected five bvdv mutants that turned out to be highly resistant to tsc but still sus ... | 2011 | 21430053 |
| the two component adjuvant ic31® potentiates the protective immunity induced by a dengue 2 recombinant fusion protein in mice. | here we evaluated the suitability of the synthetic adjuvant ic31® to potentiate the protective capacity of pd5 protein (domain iii of the envelope protein of dengue 2 virus fused to the carrier protein p64k). unlike alum, pd5 mixed with ic31® induced complete protection against virus challenge in mice and increased ifn-? secretion after in vitro re-stimulation. the induced antibody response was highly specific to the homologous serotype and showed both igg1 and igg2a subtypes. ic31® is a promisi ... | 2011 | 21447316 |
| evolution of attenuating mutations in dengue-2 strain s16803 pdk50 vaccine and comparison of growth kinetics with parent virus. | a live-attenuated dengue-2 virus strain s16803 vaccine candidate that is immunogenic and safe in humans was derived by 50 passages in primary dog kidney (pdk) cells. to identify mutations associated with attenuation of the dengue-2 pdk50 vaccine strain, we determined the nucleotide changes that arose during pdk passage of the dengue-2 virus. thirteen mutations distinguished the pdk50 virus from low-passage parent resulting in amino acid substitutions in the premembrane (e89g), envelope (e202k, n ... | 2011 | 21461924 |
| identification of cis-acting elements in the 3'-untranslated region of the dengue virus type 2 rna that modulate translation and replication. | using the massively parallel genetic algorithm for rna folding, we show that the core region of the 3'-untranslated region of the dengue virus (denv) rna can form two dumbbell structures (5' and 3'dbs) of unequal frequencies of occurrence. these structures have the propensity to form two potential pseudoknots between identical five-nucleotide terminal loops 1 and 2 (tl1 and tl2) and their complementary motifs, pk2 and pk1. mutagenesis using a denv2 replicon rna encoding the renilla luciferase re ... | 2011 | 21515677 |
| secreted dengue virus nonstructural protein ns1 is an atypical barrel-shaped high-density lipoprotein. | dengue virus (denv) causes the major arboviral disease of the tropics, characterized in its severe forms by signs of hemorrhage and plasma leakage. denv encodes a nonstructural glycoprotein, ns1, that associates with intracellular membranes and the cell surface. ns1 is eventually secreted as a soluble hexamer from denv-infected cells and circulates in the bloodstream of infected patients. extracellular ns1 has been shown to modulate the complement system and to enhance denv infection, yet its st ... | 2011 | 21518917 |
| highly conserved region 141‒168 of the ns1 protein is a new common epitope region of dengue virus. | dengue virus (denv) nonstructural protein 1 (ns1) is a major target of humoral immunity in patients and is believed to be involved in denv pathogenesis. in addition, ns1 is a diagnostic target as it is secreted, and circulates, in patients' plasma at an early stage of viral infection. in this study, we aimed to identify common epitope regions for all serotypes by preparation of mouse monoclonal antibodies (mabs) against ns1. a total of 10 out of the 20 hybridoma clones which were specific to den ... | 2011 | 21519123 |
| [circulation of a different lineage of dengue virus serotype 2 american / asian genotype in the peruvian amazon, 2010.] | our objective was to determine the genotype of the dengue virus type 2 (denv-2) that circulated in the amazon region of peru between november 2010 and january 2011. we analyzed eight samples collected during dengue surveillance activities in the cities of iquitos, yurimaguas, trujillo, tarapoto and lima between november 2010 and january 2011 that were sent to insitituto nacional de salud. the viruses were isolated in c6/36 ht cell line. viral rna was extracted and the serotype (rt - pcr multiple ... | 2011 | 21537772 |
| phylogenetic characterization of dengue virus type 2 in espírito santo, brazil. | over the last decade, the espírito santo state, brazil has become an endemic dengue fever location with annual outbreaks of varying magnitude. it is still unclear which geographical route allowed the virus entry in the state and how it has genetically changed since then. therefore we have set out to study the local molecular constitution of the virus and determine phylogenetic similarities and differences with other brazilian locations, as well as locations worldwide. viral envelope genes were p ... | 2011 | 21562769 |
| maturation of flaviviruses starts from one or more icosahedrally independent nucleation centres. | flaviviruses assemble as fusion-incompetent immature particles and subsequently undergo conformational change leading to release of infectious virions. flavivirus infections also produce combined 'mosaic' particles. here, using cryo-electron tomography, we report that mosaic particles of dengue virus type 2 had glycoproteins organized into two regions of mature and immature structure. furthermore, particles of a maturation-deficient mutant had their glycoproteins organized into two regions of im ... | 2011 | 21566648 |
| polyclonal antibodies against properly folded dengue virus ns1 protein expressed in e. coli enable sensitive and early dengue diagnosis. | the non-structural 1 (ns1) protein plays an important role in dengue diagnosis because it has been detected as a soluble serum antigen in both primary and secondary infections. the ns1 protein was expressed in escherichia coli cells, and the efficiency of four different refolding protocols was tested. all of the protocols generated dimeric ns1 in a conformation similar to that of the protein expressed by eukaryotic cells. a polyclonal antibody produced from the properly folded e. coli recombinan ... | 2011 | 21569796 |
| subcellular localizations and time-course expression of dengue envelope and non-structural 1 proteins in human endothelial cells. | we performed subcellular fractionation of human endothelial cells (ea.hy926) after a challenge with dengue virus serotype-2 (den-2) at multiplicity of infection (moi) of 10 for 2 h. the cells were fractionated into four fractions including cytosol, membrane/organelle, nucleus and cytoskeleton, and their purity was nicely confirmed by immunofluorescence staining of markers for individual subcellular compartments. western blot analysis of dengue envelope (e) and non-structural 1 (ns1) proteins sho ... | 2011 | 21575706 |
| binding of flavivirus nonstructural protein ns1 to c4b binding protein modulates complement activation. | the complement system plays a pivotal protective role in the innate immune response to many pathogens including flaviviruses. flavivirus nonstructural protein 1 (ns1) is a secreted nonstructural glycoprotein that accumulates in plasma to high levels and is displayed on the surface of infected cells but absent from viral particles. previous work has defined an immune evasion role of flavivirus ns1 in limiting complement activation by forming a complex with c1s and c4 to promote cleavage of c4 to ... | 2011 | 21642539 |
| structural mutants of dengue virus 2 transmembrane domains exhibit host-range phenotype. | there are over 700 known arboviruses and at least 80 immunologically distinct types that cause disease in humans. arboviruses are transmitted among vertebrates by biting insects, chiefly mosquitoes and ticks. these viruses are widely distributed throughout the world, depending on the presence of appropriate hosts (birds, horses, domestic animals, humans) and vectors. mosquito-borne arboviruses present some of the most important examples of emerging and resurgent diseases of global significance. | 2011 | 21658241 |
| unique heparan sulfate from shrimp heads exhibits a strong inhibitory effect on infections by dengue virus and japanese encephalitis virus. | the structure and biological activities of a highly sulfated heparan sulfate (hs) extracted from shrimp (penaeus brasiliensis) heads were characterized. structurally the shrimp hs was more heterogenous than heparin, although it is still highly sulfated. the molecular mass of the shrimp hs preparation was determined to be 32.3kda by gel filtration hplc. analysis by surface plasmon resonance demonstrated that various growth/differentiation factors specifically bound to the shrimp hs with comparabl ... | 2011 | 21806963 |
| dna vaccines against dengue virus type 2 based on truncate envelope protein or its domain iii. | two dna vaccines were constructed encoding the ectodomain (domains i, ii and iii) of the denv2 envelope protein (pe1d2) or only its domain iii (pe2d2), fused to the human tissue plasminogen activator signal peptide (t-pa). the expression and secretion of recombinant proteins was confirmed in vitro in bhk cells transfected with the two plasmids, detected by immunofluorescence or immunoprecipitation of metabolically labeled gene products, using polyclonal and monoclonal antibodies against denv2. b ... | 2011 | 21779317 |
| tripeptide inhibitors of dengue and west nile virus ns2b-ns3 protease. | a series of tripeptide aldehyde inhibitors were synthesized and their inhibitory effect against dengue virus type 2 (denv2) and west nile virus (wnv) ns3 protease was evaluated side by side with the aim to discover potent flaviviral protease inhibitors and to examine differences in specificity of the two proteases. the synthesized inhibitors feature a varied n-terminal cap group and side chain modifications of a p(2)-lysine residue. in general a much stronger inhibitory effect of the tripeptide ... | 2011 | 21763725 |
| genotype v japanese encephalitis virus is emerging. | japanese encephalitis (je) is a global public health issue that has spread widely to more than 20 countries in asia and has extended its geographic range to the south pacific region including australia. je has become the most important cause of viral encephalitis in the world. japanese encephalitis viruses (jev) are divided into five genotypes, based on the nucleotide sequence of the envelope (e) gene. the muar strain, isolated from patient in malaya in 1952, is the sole example of genotype v je ... | 2011 | 21750744 |
| recombination in the nonstructural gene region in type 2 dengue viruses. | in view of the rising prevalence of dengue virus and mixing of host and vector populations, complete full-length sequence determination of dengue strains isolated from different epidemic areas is important for the study of virus evolution, pathogenicity, vaccine efficiency and diagnosis. based on the genomic analysis of 51 complete dengue virus sequences, all of which cocirculated in thailand between 1974 and 2001, we report here the occurrence of homologous recombination in the ns5 nonstructura ... | 2011 | 21821995 |
| the ns1 glycoprotein can generate dramatic antibody-enhanced dengue viral replication in normal out-bred mice resulting in lethal multi-organ disease. | antibody-enhanced replication (aer) of dengue type-2 virus (denv-2) strains and production of antibody-enhanced disease (aed) was tested in out-bred mice. polyclonal antibodies (pabs) generated against the nonstructural-1 (ns1) glycoprotein candidate vaccine of the new guinea-c (ng-c) or nsx strains reacted strongly and weakly with these antigens, respectively. these pabs contained the igg2a subclass, which cross-reacted with the virion-associated envelope (e) glycoprotein of the denv-2 nsx stra ... | 2011 | 21731643 |
| first report of sylvatic denv-2-associated dengue hemorrhagic fever in west africa. | dengue virus (denv) circulates in human and sylvatic cycles. sylvatic strains are both ecologically and evolutionarily distinct from endemic viruses. although sylvatic dengue cycles occur in west african countries and malaysia, only a few cases of mild human disease caused by sylvatic strains and one single case of dengue hemorrhagic fever in malaysia have been reported. here we report a case of dengue hemorrhagic fever (dhf) with thrombocytopenia (13000/-ál), a raised hematocrit (32% above base ... | 2011 | 21829739 |
| vector competence of new zealand mosquitoes for selected arboviruses. | new zealand (nz) historically has been free of arboviral activity with the exception of whataroa virus (togaviridae: alphavirus), which is established in bird populations and is transmitted by local mosquitoes. this naive situation is threatened by global warming, invasive mosquitoes, and tourism. to determine the threat of selected medically important arboviruses to nz, vector competence assays were conducted using field collected endemic and introduced mosquito species. four alphaviruses (toga ... | 2011 | 21734146 |
| Chemical modifications of algal mannans and xylomannans: Effects on antiviral activity. | The structures of two sulfated xylomannans extracted from the red alga Nemalion helminthoides were determined. These two fractions plus a sulfated mannan, isolated from the same alga and whose structure was previously reported, were subjected to chemical modification. The mannan was oversulfated with SO(3)-pyridine in dimethyl sulfoxide at 60°C during two and three hours and the xylomannans were subjected to Smith degradation in order to eliminate xylose side-chains. Structural analysis of all d ... | 2012 | 22071136 |
| Analyses of mutations selected by passaging a chimeric flavivirus identify mutations that alter infectivity and reveal an interaction between the structural proteins and the nonstructural glycoprotein NS1. | We previously described a single-cycle dengue vaccine (RepliVAX D2) engineered from a capsid (C) gene-deleted West Nile virus (WNV) expressing dengue virus serotype 2 (DENV2) prM/E genes in place of the corresponding WNV genes. That work demonstrated that adaptation of RepliVAX D2 to grow in WNV C-expressing cells resulted in acquisition of non-synonymous mutations in the DENV2 prM/E and WNV NS2A/NS3 genes. Here we demonstrate that the prM/E mutations increase the specific infectivity of chimeri ... | 2011 | 21999990 |
| use of parallel validation high-throughput screens to reduce false positives and identify novel dengue ns2b-ns3 protease inhibitors. | dengue virus (denv), a mosquito-borne member of the family flaviviridae, is a significant global pathogen affecting primarily tropical and subtropical regions of the world and placing tremendous burden on the limited medical infrastructure that exists in many of the developing countries located within these regions. recent outbreaks in developed countries, including australia (hanna et al., 2009), france (la ruche et al., 2010), taiwan (kuan et al., 2010), and the usa (cdc, 2010), lead many rese ... | 2011 | 22193283 |
| ifn-γ production depends on il-12 and il-18 combined action and mediates host resistance to dengue virus infection in a nitric oxide-dependent manner. | dengue is a mosquito-borne disease caused by one of four serotypes of dengue virus (denv-1-4). severe dengue infection in humans is characterized by thrombocytopenia, increased vascular permeability, hemorrhage and shock. however, there is little information about host response to denv infection. here, mechanisms accounting for ifn-γ production and effector function during dengue disease were investigated in a murine model of denv-2 infection. ifn-γ expression was greatly increased after infecti ... | 2011 | 22206036 |
| displacement of the predominant dengue virus from type 2 to type 1 with a subsequent genotype shift from iv to i in surabaya, indonesia 2008-2010. | indonesia has annually experienced approximately 100,000 reported cases of dengue fever (df) and dengue hemorrhagic fever (dhf) in recent years. however, epidemiological surveys of dengue viruses (denvs) have been limited in this country. in surabaya, the second largest city, a single report indicated that dengue virus type 2 (denv2) was the predominant circulating virus in 2003-2005. we conducted three surveys in surabaya during: (i) april 2007, (ii) june 2008 to april 2009, and (iii) september ... | 2011 | 22087290 |
| expression and immunoaffinity purification of recombinant dengue virus 2 ns1 protein as a cleavable sumostar fusion. | dengue virus (denv) encoded nonstructural one (ns1) is a 352 amino acid protein that exists in multiple oligomeric states and is conserved within the flavivirus family. although ns1 has been heavily researched for its diagnostic utility, there is a gap in the understanding of its role in a range of viral processes, including replication and development of clinical pathologies such as vascular leakage. many of these functions involve unknown interactions with viral and host proteins. this study d ... | 2011 | 22100526 |
| antiviral activity of distictella elongata (vahl) urb. (bignoniaceae), a potentially useful source of anti-dengue drugs from the state of minas gerais, brazil. | to investigate the in vitro antiviral activity of distictella elongata (vahl) urb. ethanol extracts from leaves (lee), fruits (fee), stems and their main components. | 2011 | 21895729 |
| systems-biology approaches to discover anti-viral effectors of the human innate immune response. | virus infections elicit an immediate innate response involving antiviral factors. the activities of some of these factors are, in turn, blocked by viral countermeasures. the ensuing battle between the host and the viruses is crucial for determining whether the virus establishes a foothold and/or induces adaptive immune responses. a comprehensive systems-level understanding of the repertoire of anti-viral effectors in the context of these immediate virus-host responses would provide significant a ... | 2011 | 21994773 |
| antiviral activity of four types of bioflavonoid against dengue virus type-2. | abstract: background: dengue is a major mosquito-borne disease currently with no effective antiviral or vaccine available. effort to find antivirals for it has focused on bioflavonoids, a plant-derived polyphenolic compounds with many potential health benefits. in the present study, antiviral activity of four types of bioflavonoid against dengue virus type -2 (denv-2) in vero cell was evaluated. anti-dengue activity of these compounds was determined at different stages of denv-2 infection and ... | 2011 | 22201648 |
| [secreted expression of dengue virus type 2 envelope glycoprotein in eukaryotic cells]. | to secreted express envelope glycoprotein (e) of dengue virus type 2 extracellularly. | 2011 | 21863624 |
| clinicohematological profile and platelet trends in children with dengue during 2010 epidemic in north india. | objective: to study the clinicohematological profile and the platelet trends in children presenting with dengue infection during the 2010 dengue epidemic in north india and to compare the it with previous epidemics. methods: this retrospective study was carried out in a tertiary care hospital of north india. of the 219 children admitted from august 2010 through november 2010 with suspected dengue infection, 135 w ... | 2011 | 22037856 |
| development of dengue type-2 virus replicons expressing gfp reporter gene in study of viral rna replication. | insertion of green fluorescent protein (gfp) encoding-gene into virus genes has provided a valuable tool for flavivirus research. this study aimed to develop dengue virus (denv) replicons expressing gfp reporter that would provide a fast in vitro system to analyze functional roles of specific denv sequences in viral replication. two classes of recombinant replicon constructs were generated; one was a rna-launched replicon with a gfp gene directly inserted into a full-length denv genome (fl-denv/ ... | 2011 | 22197424 |
| internally quenched fluorescent peptide libraries with randomized sequences designed to detect endopeptidases. | identification of synthetic peptide substrates for novel peptidases is an essential step for their study. with this purpose we synthesized fluorescence resonance energy transfer (fret) peptide libraries abz (or mca)-gxxxxxq-eddnp and abz (or mca)-gxxzxxq-eddnp, where x consists of an equimolar mixture of all amino acids, the z position is fixed with one of the proteinogenic amino acids (cysteine was excluded), abz (ortho-aminobenzoic acid) or mca ([7-amino-4-methyl]coumarin) is the fluorescence ... | 2011 | 22067978 |
| b-cell responses during primary and secondary dengue virus infections in humans. | low-avidity serotype-cross-reactive antibodies are hypothesized to play a key role in triggering severe disease in patients with secondary dengue virus (denv) infection. however, there is little systematic information about the frequency, avidity, and cross-reactivity of denv-specific b cells in individuals experiencing primary instead of secondary infection. we compared denv-specific b-cell responses in a cohort of thai children with primary or secondary denv infection. b cells specific for den ... | 2011 | 21930609 |
| circulation of different lineages of dengue virus type 2 in central america, their evolutionary time-scale and selection pressure analysis. | dengue is caused by any of the four serotypes of dengue virus (denv-1 to 4). each serotype is genetically distant from the others, and each has been subdivided into different genotypes based on phylogenetic analysis. the study of dengue evolution in endemic regions is important since the diagnosis is often made by nucleic acid amplification tests, which depends upon recognition of the viral genome target, and natural occurring mutations can affect the performance of these assays. here we report ... | 2011 | 22076162 |
| analysis of the complete genome of tembusu virus, a flavivirus isolated from ducks in china. | during investigations into the outbreak of duck viral infection in 2010 in china, with a severe drop in egg production, a flavivirus was isolated from the affected ducks. it was characterized as a tembusu virus (tmuv). in this study, we obtained a complete genome sequence of tembusu virus using rt-pcr and race techniques. tmuv genome is a singled-stranded rna, with 10 990 nucleotides in length, and contains a single open reading frame (3410 amino acids) encoding 11 viral proteins with 5'and 3'no ... | 2011 | 22103739 |
| label-free electrochemical detection of the specific oligonucleotide sequence of dengue virus type 1 on pencil graphite electrodes. | a biosensor that relies on the adsorption immobilization of the 18-mer single-stranded nucleic acid related to dengue virus gene 1 on activated pencil graphite was developed. hybridization between the probe and its complementary oligonucleotides (the target) was investigated by monitoring guanine oxidation by differential pulse voltammetry (dpv). the pencil graphite electrode was made of ordinary pencil lead (type 4b). the polished surface of the working electrode was activated by applying a pot ... | 2011 | 22163916 |
| immunogenicity and protective efficacy of a vaxfectin-adjuvanted tetravalent dengue dna vaccine. | a prototype dengue-1 dna vaccine was shown to be safe and immunogenic in a previous phase 1 clinical trial. anti-dengue-1 neutralizing antibody responses were detectable only in the group of volunteers receiving the high dose of nonadjuvanted vaccine and the antibody titers were low. vaxfectin(®), a lipid-based adjuvant, enhances the immunogenicity of dna vaccines. we conducted a nonhuman primate study to evaluate the effect of vaxfectin(®) on the immunogenicity of a tetravalent dengue dna vacci ... | 2012 | 22085548 |
| Strategies to facilitate the development of uncloned or cloned infectious full-length viral cDNAs: Apple chlorotic leaf spot virus as a case study. | Approaches to simplify and streamline the construction of full-length infectious cDNA clones (FL-cDNAs) are needed. Among desirable improvements are the ability to use total nucleic acids (TNA) extracts from infected hosts (to bypass viral purification limitations) for the direct one-step amplification of large FL-cDNAs, the possibility to inoculate plants with uncloned FL-cDNAs and the simplified cloning of these large molecules. | 2011 | 22040379 |
| a thiopurine drug inhibits west nile virus production in cell culture, but not in mice. | many viruses within the flavivirus genus cause significant disease in humans; however, effective antivirals against these viruses are not currently available. we have previously shown that a thiopurine drug, 6-methylmercaptopurine riboside (6mmpr), inhibits replication of distantly related viruses within the flaviviridae family in cell culture, including bovine viral diarrhea virus and hepatitis c virus replicon. here we further examined the potential antiviral effect of 6mmpr on several diverse ... | 2011 | 22039536 |
| Insights into the internalization and retrograde trafficking of dengue 2 virus in BHK-21 cells. | Dengue virus (DENV) enters cells via endocytosis, traffics to perinuclear (PN) region, the site of morphogenesis and exits by exocytosis. This study aims to understand the role of dynamin II, endosomes, microtubules (MT) and dynein in the early events of DENV replication. | 2011 | 21991304 |
| Distinct Humoral and Cellular Immunity Induced by Alternating Prime-boost Vaccination Using Plasmid DNA and Live Viral Vector Vaccines Expressing the E Protein of Dengue Virus Type 2. | Dengue virus, which belongs to the Flavivirus genus of the Flaviviridae family, causes fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) with infection risk of 2.5 billion people worldwide. However, approved vaccines are still not available. Here, we explored the immune responses induced by alternating prime-boost vaccination using DNA vaccine, adenovirus, and vaccinia virus expressing E protein of dengue virus type 2 (DenV2). | 2011 | 22194710 |
| Establishment of a Stable Cell Line Coexpressing Dengue Virus-2 and Green Fluorescent Protein for Screening of Antiviral Compounds. | This study aimed to generate a stable cell line harboring subgenomic dengue virus replicon and a green fluorescent gene (DENV/GFP) for a cell-based model to screen anti-DENV compounds. The gene-encoding envelope protein of DENV-2 was deleted and then replaced with fragments of the GFP gene and a foot-and-mouth-disease virus 2A-derived cleavage site. The human cytomegalovirus immediate early and antisense hepatitis delta virus ribozyme sequences were added at the 5'- and 3'-ends. An internal ribo ... | 2011 | 22068705 |
| espirito santo virus: a new birnavirus that replicates in insect cells. | espirito santo virus (esv) is a newly discovered virus recovered as a contamination in a sample of a virulent strain of dengue-2 virus (strain 44/2), which was recovered from a patient in the state of espirito santo, brazil and amplified in insect cells. esv was found to be dependent upon co-infection with a virulent strain of dengue-2 and to replicate in c6/36 insect cells but not in mammalian vero cells. a sequence of the genome has been produced by de novo assembly and was not found to match ... | 2011 | 22171264 |
| expression, purification, and initial structural characterization of nonstructural protein 2b, an integral membrane protein of dengue-2 virus, in detergent micelles. | dengue virus causes serious diseases affecting people in tropical and sub-tropical regions. the nonstructural (ns) protein 2b is an integral membrane protein and important for the regulation of viral protease ns3, which is significant for virus replication. the ns2b-ns3 complex is an important drug target for treating dengue fever. however, little is known about the structure of ns2b in its entirety. herein, we describe the expression and purification of this integral membrane protein from cell ... | 2011 | 21875670 |
| [biological properties of virus dengue-3 strains isolated during the epidemic ocurred in havana, 2001-2002]. | during dengue epidemics in cuba, an increase in clinical severity with the epidemics progression in time, particularly in secondary infections, have been frequently observed. it is considered that this increase could be related with genetic changes in the circulating virus. | 2012 | 23444637 |
| effects of ribavirin and hydroxyurea on oral infection of aedes aegypti (l.) with dengue virus. | this study was conducted to determine the inhibitory effects of ribavirin and hydroxyurea on dengue virus replication in aedes aegypti mosquitoes. female ae. aegypti mosquitoes were infected with dengue-2 virus and fed ribavirin at a dose of 0.3 mg/ml and/or hydroxyurea at a dose of 6 mg/ml via artificial membrane feeding technique. the virus in infected mosquitoes was isolated using c6/36 cell culture. peroxidase-antiperoxidase (pap) staining was used to detect dengue-infected c6/36 cells and t ... | 2012 | 23413698 |
| predicting the sensitivity and specificity of published real-time pcr assays. | in recent years real-time pcr has become a leading technique for nucleic acid detection and quantification. these assays have the potential to greatly enhance efficiency in the clinical laboratory. choice of primer and probe sequences is critical for accurate diagnosis in the clinic, yet current primer/probe signature design strategies are limited, and signature evaluation methods are lacking. | 2008 | 18817537 |
| model for vaccine design by prediction of b-epitopes of iedb given perturbations in peptide sequence, in vivo process, experimental techniques, and source or host organisms. | perturbation methods add variation terms to a known experimental solution of one problem to approach a solution for a related problem without known exact solution. one problem of this type in immunology is the prediction of the possible action of epitope of one peptide after a perturbation or variation in the structure of a known peptide and/or other boundary conditions (host organism, biological process, and experimental assay). however, to the best of our knowledge, there are no reports of gen ... | 2014 | 24741624 |
| acute undifferentiated febrile illness in rural cambodia: a 3-year prospective observational study. | in the past decade, malaria control has been successfully implemented in cambodia, leading to a substantial decrease in reported cases. wide-spread use of malaria rapid diagnostic tests (rdts) has revealed a large burden of malaria-negative fever cases, for which no clinical management guidelines exist at peripheral level health facilities. as a first step towards developing such guidelines, a 3-year cross-sectional prospective observational study was designed to investigate the causes of acute ... | 2014 | 24755844 |
| single-stranded dna aptamers against pathogens and toxins: identification and biosensing applications. | molecular recognition elements (mres) can be short sequences of single-stranded dna, rna, small peptides, or antibody fragments. they can bind to user-defined targets with high affinity and specificity. there has been an increasing interest in the identification and application of nucleic acid molecular recognition elements, commonly known as aptamers, since they were first described in 1990 by the gold and szostak laboratories. a large number of target specific nucleic acids mres and their appl ... | 2015 | 26199940 |
| eating the enemy within: autophagy in infectious diseases. | autophagy is emerging as a central component of antimicrobial host defense against diverse viral, bacterial, and parasitic infections. in addition to pathogen degradation, autophagy has other functions during infection such as innate and adaptive immune activation. as an important host defense pathway, microbes have also evolved mechanisms to evade, subvert, or exploit autophagy. additionally, some fungal pathogens harness autophagy within their own cells to promote pathogenesis. this review wil ... | 2008 | 18772897 |
| ehfpi: a database and analysis resource of essential host factors for pathogenic infection. | high-throughput screening and computational technology has greatly changed the face of microbiology in better understanding pathogen-host interactions. genome-wide rna interference (rnai) screens have given rise to a new class of host genes designated as essential host factors (ehfs), whose knockdown effects significantly influence pathogenic infections. therefore, we present the first release of a manually-curated bioinformatics database and analysis resource ehfpi (essential host factors for p ... | 2014 | 25414353 |
| serratia odorifera a midgut inhabitant of aedes aegypti mosquito enhances its susceptibility to dengue-2 virus. | mosquito midgut plays a crucial role in its vector susceptibility and pathogen interaction. identification of the sustainable microflora of the midgut environment can therefore help in evaluating its contribution in mosquito-pathogen interaction and in turn vector competence. to understand the bacterial diversity in the midgut of aedes aegypti mosquitoes, we conducted a screening study of the gut microbes of these mosquitoes which were either collected from fields or reared in the laboratory "cu ... | 2012 | 22848375 |
| genome-wide rnai screen identifies novel host proteins required for alphavirus entry. | the enveloped alphaviruses include important and emerging human pathogens such as chikungunya virus and eastern equine encephalitis virus. alphaviruses enter cells by clathrin-mediated endocytosis, and exit by budding from the plasma membrane. while there has been considerable progress in defining the structure and function of the viral proteins, relatively little is known about the host factors involved in alphavirus infection. we used a genome-wide sirna screen to identify host factors that pr ... | 2013 | 24367265 |
| zikavr: an integrated zika virus resource for genomics, proteomics, phylogenetic and therapeutic analysis. | current zika virus (zikv) outbreaks that spread in several areas of africa, southeast asia, and in pacific islands is declared as a global health emergency by world health organization (who). it causes zika fever and illness ranging from severe autoimmune to neurological complications in humans. to facilitate research on this virus, we have developed an integrative multi-omics platform; zikavr (http://bioinfo.imtech.res.in/manojk/zikavr/), dedicated to the zikv genomic, proteomic and therapeutic ... | 2016 | 27633273 |
| dicer-2 processes diverse viral rna species. | rna silencing pathways play critical roles in gene regulation, virus infection, and transposon control. rna interference (rnai) is mediated by small interfering rnas (sirnas), which are liberated from double-stranded (ds)rna precursors by dicer and guide the rna-induced silencing complex (risc) to targets. although principles governing small rna sorting into risc have been uncovered, the spectrum of rna species that can be targeted by dicer proteins, particularly the viral rnas present during an ... | 2013 | 23424633 |
| diversion of stress granules and p-bodies during viral infection. | rna granules are structures within cells that impart key regulatory measures on gene expression. two general types of rna granules are conserved from yeast to mammals: stress granules (sgs), which contain many translation initiation factors, and processing bodies (p-bodies, pbs), which are enriched for proteins involved in rna turnover. because of the inverse relationship between appearance of rna granules and persistence of translation, many viruses must subvert rna granule function for replica ... | 2013 | 23290869 |
| innate antiviral immunity in drosophila. | the study of drosophila, and other genetically tractable insects, has expanded our understanding of innate immunity and more recently antiviral innate mechanisms. the drosophila antiviral program includes inflammatory signaling cascades as well as antiviral rna silencing and autophagy. this review will highlight the recent discoveries in antiviral immunity in insects and will reveal some of the lessons learned. | 0 | 20137906 |
| inhibition of the hantavirus fusion process by predicted domain iii and stem peptides from glycoprotein gc. | hantaviruses can cause hantavirus pulmonary syndrome or hemorrhagic fever with renal syndrome in humans. to enter cells, hantaviruses fuse their envelope membrane with host cell membranes. previously, we have shown that the gc envelope glycoprotein is the viral fusion protein sharing characteristics with class ii fusion proteins. the ectodomain of class ii fusion proteins is composed of three domains connected by a stem region to a transmembrane anchor in the viral envelope. these fusion protein ... | 2016 | 27414047 |
| standing your ground to exoribonucleases: function of flavivirus long non-coding rnas. | members of the flaviviridae (e.g., dengue virus, west nile virus, and hepatitis c virus) contain a positive-sense rna genome that encodes a large polyprotein. it is now also clear most if not all of these viruses also produce an abundant subgenomic long non-coding rna. these non-coding rnas, which are called subgenomic flavivirus rnas (sfrnas) or xrn1-resistant rnas (xrrnas), are stable decay intermediates generated from the viral genomic rna through the stalling of the cellular exoribonuclease ... | 2015 | 26368052 |
| rna interference-mediated antiviral defense in insects. | small interfering rna (sirna)-mediated rna interference (rnai) pathways are critical for the detection and inhibition of rna virus replication in insects. recent work has also implicated rnai pathways in the establishment of persistent virus infections and in the control of dna virus replication. accumulating evidence suggests that diverse double-stranded rnas produced by rna and dna viruses can trigger rnai responses yet many viruses have evolved mechanisms to inhibit rnai defenses. therefore, ... | 0 | 26034705 |
| expanding the proteome of an rna virus by phosphorylation of an intrinsically disordered viral protein. | the human proteome contains myriad intrinsically disordered proteins. within intrinsically disordered proteins, polyproline-ii motifs are often located near sites of phosphorylation. we have used an unconventional experimental paradigm to discover that phosphorylation by protein kinase a (pka) occurs in the intrinsically disordered domain of hepatitis c virus non-structural protein 5a (ns5a) on thr-2332 near one of its polyproline-ii motifs. phosphorylation shifts the conformational ensemble of ... | 2014 | 25031324 |
| isolation of midgut escape mutants of two american genotype dengue 2 viruses from aedes aegypti. | several studies have shown that american genotype dengue 2 viruses (denv2) have reduced viral fitness in the mosquito vector, aedes aegypti, compared to other denv2 genotypes. diminished replication efficiency or inability to efficiently traverse membrane barriers encompassing organs such as the midgut or salivary glands are considered major factors negatively impacting viral fitness in the mosquito. | 2013 | 23937713 |
| transgene-mediated suppression of the rna interference pathway in aedes aegypti interferes with gene silencing and enhances sindbis virus and dengue virus type 2 replication. | rna interference (rnai) is the major innate antiviral pathway in aedes aegypti that responds to replicating arboviruses such as dengue virus (denv) and sindbis virus (sinv). on the one hand, the mosquito's rnai machinery is capable of completely eliminating denv2 from ae. aegypti. on the other, transient silencing of key genes of the rnai pathway increases replication of sinv and denv2, allowing the viruses to temporally overcome dose-dependent midgut infection and midgut escape barriers (meb) m ... | 0 | 23331493 |
| chloroquine inhibits dengue virus type 2 replication in vero cells but not in c6/36 cells. | dengue viruses are the most important arthropod-borne viruses in terms of morbidity and mortality in the world. since there is no dengue vaccine available for human use, we have set out to investigate the use of chloroquine as an antiviral drug against dengue. chloroquine, an amine acidotropic drug known to affect intracellular exocytic pathways by increasing endosomal ph, was used in the in vitro treatment of vero and c6/36 cells infected with dengue virus type 2 (denv-2). real-time rt-pcr and ... | 2013 | 23431254 |
| testing of novel dengue virus 2 vaccines in african green monkeys: safety, immunogenicity, and efficacy. | the immunogenicity and safety of three novel host-range vaccines containing deletions in the transmembrane domain of dengue virus serotype 2 (dv2) e glycoprotein were evaluated in african green monkeys. the shorter transmembrane domains are capable of functionally spanning an insect but not a mammalian cell membrane, resulting in production of viral mutants that have reduced infectivity in mammalian hosts but efficient growth in insect cells. groups of four monkeys received one dose each of test ... | 2012 | 22890035 |
| dengue virus infection perturbs lipid homeostasis in infected mosquito cells. | dengue virus causes ∼50-100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. during its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. this phenomenon is observed both in human and vector-derived cells. using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus ... | 2012 | 22457619 |
| virus-derived sirnas and pirnas in immunity and pathogenesis. | cellular organisms have evolved related pathways for the biogenesis and function of small interfering rnas (sirnas), micrornas and piwi-interacting rnas (pirnas). these distinct classes of small rnas guide specific gene silencing at both transcriptional and posttranscriptional levels by serving as specificity determinants. small rnas of virus and host origins have been found to modulate virus–host interactions by rna interference (rnai), leading to antiviral immunity or viral pathogenesis. deep ... | 0 | 22180767 |
| genetic dissection of flaviviridae host factors through genome-scale crispr screens. | the flaviviridae are a family of viruses that cause severe human diseases. for example, dengue virus (denv) is a rapidly emerging pathogen causing an estimated 100 million symptomatic infections annually worldwide. no approved antivirals are available to date and clinical trials with a tetravalent dengue vaccine showed disappointingly low protection rates. hepatitis c virus (hcv) also remains a major medical problem, with 160 million chronically infected patients worldwide and only expensive tre ... | 0 | 27383987 |
| a de novo transcriptome analysis shows that modulation of the jak-stat signaling pathway by salmonid alphavirus subtype 3 favors virus replication in macrophage/dendritic-like to-cells. | the janus kinase (jak) and signaling transducer activator of transcription (stat) pathway mediates the signaling of genes required for cellular development and homeostasis. to elucidate the effect of type i ifn on the jak/stat pathway in salmonid alphavirus subtype 3 (sav3) infected macrophage/dendritic like to-cells derived from atlantic salmon (salmo salar l) headkidney leukocytes, we used a differential transcriptome analysis by rna-seq and the kyoto encyclopedia of genes and genomes (keggs) ... | 2016 | 27215196 |
| small rna profiling in dengue virus 2-infected aedes mosquito cells reveals viral pirnas and novel host mirnas. | in aedes mosquitoes, infections with arthropod-borne viruses (arboviruses) trigger or modulate the expression of various classes of viral and host-derived small rnas, including small interfering rnas (sirnas), piwi interacting rnas (pirnas), and micrornas (mirnas). viral sirnas are at the core of the antiviral rna interference machinery, one of the key pathways that limit virus replication in invertebrates. besides sirnas, aedes mosquitoes and cells derived from these insects produce arbovirus-d ... | 2016 | 26914027 |
| flavivirus sfrna suppresses antiviral rna interference in cultured cells and mosquitoes and directly interacts with the rnai machinery. | productive arbovirus infections require mechanisms to suppress or circumvent the cellular rna interference (rnai) pathway, a major antiviral response in mosquitoes. in this study, we demonstrate that two flaviviruses, dengue virus and kunjin virus, significantly repress sirna-mediated rnai in infected human cells as well as during infection of the mosquito vector culex quinquefasciatus. arthropod-borne flaviviruses generate a small structured non-coding rna from the viral 3' utr referred to as s ... | 2015 | 26331679 |
| the interferon-inducible mouse apolipoprotein l9 and prohibitins cooperate to restrict theiler's virus replication. | apolipoprotein l9b (apol9b) is an interferon-stimulated gene (isg) that has antiviral activity and is weakly expressed in primary mouse neurons as compared to other cell types. here, we show that both apol9 isoforms (apol9b and apol9a) inhibit replication of theiler's murine encephalomyelitis virus (tmev) but not replication of vesicular stomatitis virus (vsv), murid herpesvirus-4 (muhv-4), or infection by a lentiviral vector. apol9 genes are strongly expressed in mouse liver and, to a lesser ex ... | 2015 | 26196674 |
| xrn1 stalling in the 5' utr of hepatitis c virus and bovine viral diarrhea virus is associated with dysregulated host mrna stability. | we demonstrate that both hepatitis c virus (hcv) and bovine viral diarrhea virus (bvdv) contain regions in their 5' utrs that stall and repress the enzymatic activity of the cellular 5'-3' exoribonuclease xrn1, resulting in dramatic changes in the stability of cellular mrnas. we used biochemical assays, virus infections, and transfection of the hcv and bvdv 5' untranslated regions in the absence of other viral gene products to directly demonstrate the existence and mechanism of this novel host-v ... | 2015 | 25747802 |
| oxidative stress influences positive strand rna virus genome synthesis and capping. | flaviviruses are 5' capped positive-stranded rna viruses that replicate their genomes within endoplasmic reticulum-derived vesicles. flaviviruses are well known to induce oxidative stress late in infection but it is unknown if oxidative stress plays a positive role in the viral rna replication cycle. we therefore examined how oxidation affects flavivirus rna replication. we found that antioxidant treatment reduced virus production, reduced the viral positive-to-negative strand rna ratio, and res ... | 2014 | 25514423 |
| microrna-like viral small rna from dengue virus 2 autoregulates its replication in mosquito cells. | micrornas (mirnas) are small regulatory rnas that play significant roles in most cellular processes. in the seemingly endless arms race between hosts and pathogens, viruses also encode mirnas that facilitate successful infection. in search of functional mirnas or viral small rnas (vsrnas) encoded by dengue virus (denv), deep sequencing data of virus-infected aedes aegypti mosquitoes were used. from six vsrnas, with candidate stem-loop structures in the 5' and 3' untranslated regions of the viral ... | 2014 | 24550303 |