| construction of an internal rt-pcr standard control for the detection of human caliciviruses in stool. | rt-pcr is the most sensitive assay for the detection of human caliciviruses (hucv) in stool and environmental samples. however, false negative results are commonly obtained due to the presence of rt-pcr inhibitors. in order to exclude such false negative results, an internal control (ic) was developed for the assay by cloning a 319 nt sequence of the norwalk virus (nv) polymerase containing a 156 nt cdna insert. the rt-pcr assay was carried out using rna derived from the constructed plasmid and ... | 2006 | 16857274 |
| [molecular epidemiological study of human calicivirus infection in diarrhea children in autumn and winter at a hospital in guangzhou]. | to investigate the epidemiological features of human calicivirus( hucv) infection in children with diarrhea in a hospital in guangzhou. | 2006 | 16864088 |
| characterization of a cross-reactive linear epitope in human genogroup i and bovine genogroup iii norovirus capsid proteins. | the southampton norovirus (sv) capsid protein was expressed as vlps by recombinant baculoviruses in insect cells and was used to immunize mice for the production of monoclonal antibodies (mabs). one mab, cm54, showed broad cross-reactivity to genogroup i (gi) noroviruses, but was not reactive to gii capsid proteins. interestingly mab cm54 reacted to a bovine norovirus capsid protein. immunoblot analysis indicated the binding site for cm54 was located in the shell domain between amino acid residu ... | 2006 | 16934306 |
| virus-like particles production in green plants. | viruses-like particles (vlps), assembled from capsid structural subunits of several different viruses, have found a number of biomedical applications such as vaccines and novel delivery systems for nucleic acids and small molecules. production of recombinant proteins in different plant systems has been intensely investigated and improved upon in the last two decades. plant-derived antibodies, vaccines, and microbicides have received great attention and shown immense promise. in the case of mucos ... | 2006 | 16997715 |
| library screen for inhibitors targeting norovirus binding to histo-blood group antigen receptors. | human noroviruses (nvs) are a common cause of nonbacterial gastroenteritis. the disease is difficult to control due to its widespread nature and the lack of antivirals or vaccines against nvs. the recent identification of human histo-blood group antigens (hbgas) as nv receptors opens a new way for the discovery and design of antivirals against nvs. a saliva-based enzyme immune assay (eia) was used to screen a synthetic-compound library for inhibition of the binding of norovirus-like particles to ... | 2007 | 17060523 |
| virological investigation on aerosol from waste depuration plants. | aerosol from activated mud decontamination plants used for the treatment of urban sewage can represent a vehicle for bacteria, virus and fungi. as a result, they become an infective hazard for plant personnel, the general population residing in the surrounding area and the occasional visitor. the present investigation focuses on the identification of enteric-type viruses in this kind of aerosol. the following methods were employed on 214 samples collected in the 1999-2000 period: cell culture (b ... | 2006 | 17061403 |
| presence of a surface-exposed loop facilitates trypsinization of particles of sinsiro virus, a genogroup ii.3 norovirus. | noroviruses (novs) are the causative agents of nonbacterial acute gastroenteritis in humans. novs that belong to genogroup ii (gii) are quite prevalent and prone to undergo recombination, and their three-dimensional structure is not yet known. protein homology modeling of sinsiro virus (sv), a member of the gii.3 novs, revealed the presence of a surface-exposed 20-amino-acid (aa) insertion in the p2 domain of the capsid protein (cp) relative to the norwalk virus (nv) cp, which is a well known ho ... | 2007 | 17079293 |
| norovirus binds to blood group a-like antigens in oyster gastrointestinal cells. | to determine if histo-blood group antigens (hbga) present in oyster gastrointestinal (gi) cells mediate accumulation of human noroviruses (nov) in oyster gi cells. | 2006 | 17083711 |
| high efficiency cross-reactive monoclonal antibody production by oral immunization with recombinant norwalk virus-like particles. | monoclonal antibodies (mabs) are important for in-depth antigenic characterization and diagnosis of infections with human caliciviruses that cause almost all outbreaks of nonbacterial gastroenteritis. we compared different routes of immunization with nonreplicating virus-like particles (vlps) from recombinant norwalk virus (rnv) and recombinant mexico virus (rmx) administered to balb/c mice to determine the efficiency of hybridoma production. oral immunization with vlps without adjuvant resulted ... | 2006 | 17116984 |
| norovirus capsid protein expressed in yeast forms virus-like particles and stimulates systemic and mucosal immunity in mice following an oral administration of raw yeast extracts. | norovirus (nv) gastroenteritis is a widespread disease affecting people of all ages worldwide. a simple, safe, and easily deliverable vaccine may be the key for the control and prevention of nv gastroenteritis. in this study, we demonstrated that a nv recombinant capsid protein (strain va387, genogroup ii.4) expressed in yeast (pichia pastoris) spontaneously formed virus-like particles (vlps) like those expressed in other in vitro systems. oral administration of raw material from the yeast cell ... | 2007 | 17133551 |
| tomato is a highly effective vehicle for expression and oral immunization with norwalk virus capsid protein. | norwalk virus (nv) is an important agent of epidemic gastroenteritis, and an oral subunit vaccine shows potential for protection. recombinant norwalk virus (rnv) capsid protein expressed in plants assembles virus-like particles (vlps) that are orally immunogenic in mice and humans. in this article we examine rnv expression in tomato and potato using a plant-optimized gene, and test the immunogenicity of dried tomato fruit and potato tuber fed to mice. the synthetic gene increased rnv expression ... | 2006 | 17177807 |
| human sapoviruses: genetic diversity, recombination, and classification. | the family caliciviridae contains four genera sapovirus, norovirus, lagovirus and vesivirus, which include sapporo virus (sav), norwalk virus (nov), rabbit hemorrhagic disease virus (rhdv) and feline calicivirus (fcv), respectively. sav is a causative agent of gastroenteritis in children and adults. sav can be divided into five genogroups (gi-gv), among which gi, gii, giv and gv are known to infect humans, whereas sav giii infects porcine species. detection methods include elisa, rt-pcr and real ... | 2007 | 17340567 |
| epochal evolution of ggii.4 norovirus capsid proteins from 1995 to 2006. | noroviruses are the causative agents of the majority of viral gastroenteritis outbreaks in humans. during the past 15 years, noroviruses of genotype ggii.4 have caused four epidemic seasons of viral gastroenteritis, during which four novel variants (termed epidemic variants) emerged and displaced the resident viruses. in order to understand the mechanisms and biological advantages of these epidemic variants, we studied the genetic changes in the capsid proteins of ggii.4 strains over this period ... | 2007 | 17609280 |
| a single-amino-acid substitution in the p2 domain of vp1 of murine norovirus is sufficient for escape from antibody neutralization. | noroviruses cause epidemic outbreaks of acute viral gastroenteritis worldwide, and the number of reported outbreaks is increasing. human norovirus strains do not grow in cell culture. however, murine norovirus (mnv) replicates in the raw 264.7 macrophage cell line and thus provides a tractable model to investigate norovirus interactions with host cells. epitopes recognized by monoclonal antibodies (mabs) against the human norovirus strains norwalk virus and snow mountain virus (smv) identified r ... | 2007 | 17804495 |
| norwalk virus rna is infectious in mammalian cells. | human noroviruses are positive-sense rna viruses and are the leading cause of epidemic acute viral gastroenteritis in developed countries. the absence of an in vitro cell culture model for human norovirus infection has limited the development of effective antivirals and vaccines. human histo-blood group antigens have been regarded as receptors for norovirus infection, and expression of the alpha(1,2) fucosyltransferase gene (fut2) responsible for the secretor phenotype is required for susceptibi ... | 2007 | 17855551 |
| interferons and ribavirin effectively inhibit norwalk virus replication in replicon-bearing cells. | the development of effective therapies for noroviral gastroenteritis has been hampered by the absence of a cell culture system. recently, we reported the generation of norwalk virus (nv) replicon-bearing cells in bhk21 and huh-7 cells and demonstrated that alpha interferon (ifn-alpha) effectively inhibited the replication of nv in these cells. in continuing studies for screening potential antinoroviral agents, we tested ifn-gamma and ribavirin for their effects on nv replication in the cells. li ... | 2007 | 17855555 |
| [cloning, expression and immunocharacterization of the capsid protein of human norwalk virus guangzhou strain nvgz01]. | to clone, express and characterize the capsid protein of human norwalk virus guangzhou strain nvgz01. | 2007 | 17884790 |
| norovirus recognizes histo-blood group antigens on gastrointestinal cells of clams, mussels, and oysters: a possible mechanism of bioaccumulation. | outbreaks of norovirus (nov) gastroenteritis are often associated with the consumption of contaminated bivalves such as oysters, clams, and mussels. crassostrea virginica oysters trap the norwalk virus through the intestinal type a-like histo-blood group antigen (hbga), a possible mechanism of bioaccumulation responsible for nov outbreaks. in this study, we tested binding and inhibition of binding in three species of oysters and one species each of clams and mussels with novs, representing four ... | 2007 | 17900094 |
| study: fast-moving norwalk virus requires hospitals to go beyond standard infection control. | | 2007 | 17977256 |
| evaluation of murine norovirus, feline calicivirus, poliovirus, and ms2 as surrogates for human norovirus in a model of viral persistence in surface water and groundwater. | human noroviruses (novs) are a significant cause of nonbacterial gastroenteritis worldwide, with contaminated drinking water a potential transmission route. the absence of a cell culture infectivity model for nov necessitates the use of molecular methods and/or viral surrogate models amenable to cell culture to predict nov inactivation. the nov surrogates murine nov (mnv), feline calicivirus (fcv), poliovirus (pv), and male-specific coliphage ms2, in conjunction with norwalk virus (nv), were spi ... | 2008 | 18065626 |
| norwalk virus - off and running. | | 2003 | 18159419 |
| structural insights into mechanisms of catalysis and inhibition in norwalk virus polymerase. | crystal structures of norwalk virus polymerase bound to an rna primer-template duplex and either the natural substrate ctp or the inhibitor 5-nitrocytidine triphosphate have been determined to 1.8a resolution. these structures reveal a closed conformation of the polymerase that differs significantly from previously determined open structures of calicivirus and picornavirus polymerases. these closed complexes are trapped immediately prior to the nucleotidyl transfer reaction, with the triphosphat ... | 2008 | 18184655 |
| transmission events within outbreaks of gastroenteritis determined through analysis of nucleotide sequences of the p2 domain of genogroup ii noroviruses. | tracking the spread of noroviruses during outbreaks of gastroenteritis is hampered by the lack of sequence diversity in those regions of the genome chosen for virus detection and characterization. sequence analysis of regions of the genes encoding the rna-dependent rna polymerase and the s domain of the capsid does not provide sufficient discrimination between genotypically related strains of different outbreaks. however, analysis of sequences derived from the region encoding the p2 domain showe ... | 2008 | 18216210 |
| two cases of norwalk virus enteritis following small bowel transplantation treated with oral human serum immunoglobulin. | protracted diarrhea is a challenging problem after small bowel transplantation. we report two patients who developed norwalk virus enteritis after small bowel transplantation. both received oral hsig with resolution of diarrhea within 48 h. | 2008 | 18221419 |
| [outbreak of gastroenteritis by norwalk virus in nursing home]. | | 2008 | 18261386 |
| investigation on virucidal activity of chlorine dioxide. experimental data on feline calicivirus, hav and coxsackie b5. | the aim of this study was to evaluate the efficacy of clo2 with regard to viruses which show a particular resistance to oxidizing agent such as hav and norwalk and norwalk-like viruses, and which play an important role in the epidemiology of viral foodborne diseases. in the food industry, disinfection of processing systems and equipment is a very important instrument to prevent secondary contamination and to guarantee food safety. among disinfectants, chlorine dioxide (clo2) presents a good effi ... | 2007 | 18274345 |
| physical stabilization of norwalk virus-like particles. | virus-like particles (vlps) used as vaccine antigens often elicit strong immune responses due to their intrinsic repetitive, high-density display of epitopes, and the fact that the mammalian immune system is highly attuned to recognizing particles in the size range of viruses (20-150 nm). to retain these immunogenic qualities, vaccines that utilize virus-like particle (vlp) antigens should be formulated to stabilize both native conformational epitopes and the overall particulate nature of the vl ... | 2008 | 18300304 |
| an efficient plant viral expression system generating orally immunogenic norwalk virus-like particles. | virus-like particles (vlps) derived from enteric pathogens like norwalk virus (nv) are well suited to study oral immunization. we previously described stable transgenic plants that accumulate recombinant nv-like particles (rnvs) that were orally immunogenic in mice and humans. the transgenic approach suffers from long generation time and modest level of antigen accumulation. we now overcome these constraints with an efficient tobacco mosaic virus (tmv)-derived transient expression system using l ... | 2008 | 18325641 |
| [interaction between noroviruses and human histo-blood group antigens]. | norovirus (nov), a member of the family caliciviridae, is a major cause of water and food-borne acute nonbacterial gastroenteritis, and forms many morphologically similar but antigenically diverse groups of viruses. the virus-like particles (vlps) derived from the prototype strain of nov, norwalk virus (nv/68), bind to histo-blood group antigens (hbgas). hbgas are carbohydrates that contain structurally related saccharide moieties, and are found in saliva and mucosal secretions from intestinal e ... | 2007 | 18357756 |
| infant mental health assessment: the use of dc 0-3 in an outpatient child psychiatric clinic in scandinavia. | the study focuses on infant mental health data from an outpatient psychiatric clinic using the "diagnostic classification of mental health and developmental disorders of infancy and early childhood" (dc 0-3) and parental questionnaires, cbcl and itsc. in total, 138 infants (aged 0-3) went through the diagnostic procedure. sixty-eight per cent were diagnosed within axis i, with regulatory disorder, disorder of affect and traumatic stress disorder being the most frequent diagnoses. in addition, 48 ... | 2008 | 18363590 |
| [microbiological aspects of pool water]. | it is well known that there is an elevated risk of diffusion of pathogenic micro-organisms in swimming pools. preventive measures aimed at protecting the health of swimmers are complex because of the variety of micro-organisms involved, the different ways in which these can be transmitted and the involvement of both aquatic and environmental factors. in industrialised countries, the circulation of many pathogens which were common in the past has progressively decreased in recent years; in contra ... | 2008 | 18379609 |
| structural basis for the receptor binding specificity of norwalk virus. | noroviruses are positive-sense, single-stranded rna viruses that cause acute gastroenteritis. they recognize human histo-blood group antigens as receptors in a strain-specific manner. the structures presented here were analyzed in order to elucidate the structural basis for differences in ligand recognition of noroviruses from different genogroups, the prototypic norwalk virus (nv; gi-1) and va387 (gii-4), which recognize the same a antigen but differ in that nv is unable to bind to the b antige ... | 2008 | 18385236 |
| herpes simplex virus nv1020 as a novel and promising therapy for hepatic malignancy. | patients with hepatic malignancy have a dismal prognosis with standard therapies. nv1020 is an oncolytic herpes simplex virus that has potential to be a safe and effective therapeutic agent for this disease. | 2008 | 18549346 |
| norwalk virus: how infectious is it? | noroviruses are major agents of viral gastroenteritis worldwide. the infectivity of norwalk virus, the prototype norovirus, has been studied in susceptible human volunteers. a new variant of the hit theory model of microbial infection was developed to estimate the variation in norwalk virus infectivity, as well as the degree of virus aggregation, consistent with independent (electron microscopic) observations. explicit modeling of viral aggregation allows us to express virus infectivity per sing ... | 2008 | 18551613 |
| atomic resolution structural characterization of recognition of histo-blood group antigens by norwalk virus. | members of norovirus, a genus in the family caliciviridae, are causative agents of epidemic diarrhea in humans. susceptibility to several noroviruses is linked to human histo-blood type, and its determinant histo-blood group antigens (hbgas) are regarded as receptors for these viruses. specificity for these carbohydrates is strain-dependent. norwalk virus (nv) is the prototype genogroup i norovirus that specifically recognizes a- and h-type hbga, in contrast to genogroup ii noroviruses that exhi ... | 2008 | 18599458 |
| leader of the capsid protein in feline calicivirus promotes replication of norwalk virus in cell culture. | the inability to grow human noroviruses in cell culture has greatly impeded the studies of their pathogenesis and immunity. vesiviruses, in the family caliciviridae, grow efficiently in cell culture and encode a unique protein in the subgenomic region designated as leader of the capsid protein (lc). we hypothesized that lc might be associated with the efficient replication of vesiviruses in cell culture and promote the replication of human norovirus in cells. to test this hypothesis, a recombina ... | 2008 | 18632864 |
| noroviruses distinguish between type 1 and type 2 histo-blood group antigens for binding. | norovirus (nov) is a causative agent of acute gastroenteritis. nov binds to histo-blood group antigens (hbgas), namely, abh antigens and lewis (le) antigens, in which type 1 and type 2 carbohydrate core structures constitute antigenically distinct variants. norwalk virus, the prototype strain of norovirus, binds to the gastroduodenal junction, and this binding is correlated with the presence of h type 1 antigen but not with that of h type 2 antigen (s. marionneau, n. ruvoen, b. le moullac-vaidye ... | 2008 | 18701592 |
| inactivation of norovirus by chlorine disinfection of water. | in an effort to validate previous research suggesting remarkable resistance of norovirus to free chlorine disinfection, we characterized the disinfection response of purified and dispersed norwalk virus (nv) by bench-scale free chlorine disinfection using rt-pcr for virus assays. the inactivation of nv by two doses of free chlorine (1 and 5mg/l) at ph 6 and 5 degrees c based on two rt-pcr assays was similar to that of coliphage ms2, but much faster than that of poliovirus 1. despite the underest ... | 2008 | 18760818 |
| histo-blood group antigen assay for detecting noroviruses in water. | we evaluated a novel, magnetic-bead-based histo-blood group antigen assay for the recovery of low numbers of norovirus particles. using this assay, with norwalk virus seeded in environmental waters as a model, we were able to recover 30 to 300 genomic copies of the virus. | 2008 | 18776025 |
| inhibition of norovirus replication by morpholino oligomers targeting the 5'-end of the genome. | noroviruses are an important cause of non-bacterial epidemic gastroenteritis, but no specific antiviral therapies are available. we investigated the inhibitory effect of phosphorodiamidiate morpholino oligomers (pmos) targeted against norovirus sequences. a panel of peptide-conjugated pmos (ppmos) specific for the murine norovirus (mnv) genome was developed, and two ppmo compounds directed against the first aug of the orf1 coding sequence near the 5'-end of the genome proved effective in inhibit ... | 2008 | 18783811 |
| norwalk virus shedding after experimental human infection. | noroviruses are the most common cause of viral gastroenteritis in the united states. to determine the magnitude and duration of virus shedding in feces, we evaluated persons who had been experimentally infected with norwalk virus. of 16 persons, clinical gastroenteritis (watery diarrhea and/or vomiting) developed in 11; symptomatic illness lasted 1-2 days. virus shedding was first detected by reverse transcription-pcr (rt-pcr) 18 hours after participant inoculation and lasted a median of 28 days ... | 2008 | 18826818 |
| [the outbreak of acute gastroenteritis caused by norwalk like viruses in zadar general hospital (2007)]. | early detection of clinical signs and symptoms of acute gastroenteritis and appropriate preventive measures to stop the spread of infection. | 2008 | 18843852 |
| [rotavirus and other viruses causing acute childhood gastroenteritis]. | acute gastroenteritis is one of the most common diseases, affecting children worldwide. viruses are recognized as a major cause of this disease, particularly in children. since the norwalk virus was identified as a cause of gastroenteritis, the number of viral agents associated with diarrheal disease in humans has progressively increased. rotavirus is the most common cause of severe diarrhea in children under 5 years of age. human astroviruses, caliciviruses and enteric adenovirus are also impor ... | 2008 | 19100169 |
| new electropositive filter for concentrating enteroviruses and noroviruses from large volumes of water. | the u.s. environmental protection agency's information collection rule requires the use of 1mds electropositive filters for concentrating enteric viruses from water, but unfortunately, these filters are not cost-effective for routine viral monitoring. in this study, an inexpensive electropositive cartridge filter, the nanoceram filter, was evaluated for its ability to concentrate enteroviruses and noroviruses from large volumes of water. seeded viruses were concentrated using the adsorption-elut ... | 2009 | 19218410 |
| a dna replicon system for rapid high-level production of virus-like particles in plants. | recombinant virus-like particles (vlps) represent a safe and effective vaccine strategy. we previously described a stable transgenic plant system for inexpensive production and oral delivery of vlp vaccines. however, the relatively low-level antigen accumulation and long-time frame to produce transgenic plants are the two major roadblocks in the practical development of plant-based vlp production. in this article, we describe the optimization of geminivirus-derived dna replicon vectors for rapid ... | 2009 | 19309755 |
| cellular proteins mediate 5'-3' end contacts of norwalk virus genomic rna. | long-range rna-rna interactions between the 5' and 3' ends are a common feature involved in the regulation of both the initiation of translation and the synthesis of the viral genomic rnas. these interactions either take place by direct rna-rna contacts or can be mediated by proteins. by in silico analysis, we found three possible complementary sequences (cs) between the 5' and the 3' ends of the norwalk virus genomic rna. co-precipitation assays demonstrated that physical contacts between the 5 ... | 2009 | 19324388 |
| conservation of carbohydrate binding interfaces: evidence of human hbga selection in norovirus evolution. | human noroviruses are the major viral pathogens of epidemic acute gastroenteritis. these genetically diverse viruses comprise two major genogroups (gi and gii) and approximately 30 genotypes. noroviruses recognize human histo-blood group antigens (hbgas) in a diverse, strain-specific manner. recently the crystal structures of the hbga-binding interfaces of the gi norwalk virus and the gii va387 have been determined, which allows us to examine the genetic and structural relationships of the hbga- ... | 2009 | 19337380 |
| use of gfp to investigate expression of plant-derived vaccines. | plants are low-cost bioreactors for the production of various biopharmaceuticals including oral vaccines. plant-derived oral vaccines are potentially useful in combating viral infections involving mucosal immunity. transgenic plants have been generated to successfully produce mucosal vaccines against cholera, hepatitis b, foot-and-mouth disease, and norwalk virus. as a first step toward the generation of oral vaccines against the severe acute respiratory syndrome coronavirus (sars-cov), we have ... | 2009 | 19378126 |
| norwalk virus-like particles bind specifically to a, h and difucosylated lewis but not to b histo-blood group active glycosphingolipids. | noroviruses and norovirus virus-like particles (vlps) exhibit strain specific patterns in their binding to abh and lewis histo-blood group antigens. in this study we demonstrate for the first time specific binding of norwalk virus vlps to type 1 and type 2 chain glycosphingolipids (gsls) carrying abh and lewis antigens. n-succinimidyl-3-tributylstannyl benzoate (ate) was precursor labeled with (125)i and then conjugated to vlps. the (125)i-vlps were used in gsl thin-layer chromatogram binding as ... | 2009 | 19387828 |
| role of cholesterol pathways in norovirus replication. | norwalk virus (nv) is a prototype strain of the noroviruses (family caliciviridae) that have emerged as major causes of acute gastroenteritis worldwide. i have developed nv replicon systems using reporter proteins such as a neomycin-resistant protein (nv replicon-bearing cells) and a green fluorescent protein (pnv-gfp) and demonstrated that these systems were excellent tools to study virus replication in cell culture. in the present study, i first performed dna microarray analysis of the replico ... | 2009 | 19515767 |
| [noroviruses--tactic of spread]. | noroviruses are the commonest cause of nonbacterial acute gastroenteritis worldwide. food and water are considered as the main source of the food-borne infections in humans. noroviruses outbreaks are frequently associated with semiclosed or closed institutions such as hospitals, homes for the elderly, schools. transmission of noroviruses is usually person-to-person, although food and environmental or airborne contamination have all been implicated in transmission and are members of the calicivir ... | 2009 | 19522218 |
| multiplex primer prediction software for divergent targets. | we describe a multiplex primer prediction (mpp) algorithm to build multiplex compatible primer sets to amplify all members of large, diverse and unalignable sets of target sequences. the mpp algorithm is scalable to larger target sets than other available software, and it does not require a multiple sequence alignment. we applied it to questions in viral detection, and demonstrated that there are no universally conserved priming sequences among viruses and that it could require an unfeasibly lar ... | 2009 | 19759213 |
| [rapid detection of norwalk gii with reverse transcription loop-mediated isothermal amplification]. | to develop a reverse transcription-loop-mediated isothermal amplification (rt-lamp) assay for rapid and sensitive detection of norwalk gii. 4 primers which recognized 6 distinct regions on the rna-dependent rna polymerase gene of norwalk gii were designed and used for lamp assay. norwalk gii rna was amplified under isothermal conditions (65 degrees c) for 120 min, and lamp results were then judged with naked eye, sybr green i staining, electrophoretic analysis and restriction digestion. to evalu ... | 2009 | 19769163 |
| metagenomic analysis of rna viruses in a fresh water lake. | freshwater lakes and ponds present an ecological interface between humans and a variety of host organisms. they are a habitat for the larval stage of many insects and may serve as a medium for intraspecies and interspecies transmission of viruses such as avian influenza a virus. furthermore, freshwater bodies are already known repositories for disease-causing viruses such as norwalk virus, coxsackievirus, echovirus, and adenovirus. while rna virus populations have been studied in marine environm ... | 2009 | 19787045 |
| effectiveness of liquid soap and hand sanitizer against norwalk virus on contaminated hands. | disinfection is an essential measure for interrupting human norovirus (hunov) transmission, but it is difficult to evaluate the efficacy of disinfectants due to the absence of a practicable cell culture system for these viruses. the purpose of this study was to screen sodium hypochlorite and ethanol for efficacy against norwalk virus (nv) and expand the studies to evaluate the efficacy of antibacterial liquid soap and alcohol-based hand sanitizer for the inactivation of nv on human finger pads. ... | 2010 | 19933337 |
| heterotypic humoral and cellular immune responses following norwalk virus infection. | norovirus immunity is poorly understood as the limited data available on protection after infection are often contradictory. in contrast to the more prominent gii noroviruses, gi norovirus infections are less frequent in outbreaks. the gi noroviruses display very complex patterns of heterotypic immune responses following infection, and many individuals are highly susceptible to reinfection. to study the immune responses and mechanisms of gi.1 persistence, we built structural models and recombina ... | 2010 | 20007270 |
| norovirus diarrhoeal disease in infants and children. | | 2010 | 20078416 |
| norwalk virus-like particles as vaccines. | noroviruses (nov) cause the great majority of epidemic nonbacterial gastroenteritis in humans. expression of the capsid protein in recombinant systems, including insect and plant cells, yields assembly of virus-like particles (vlps) that mimic the antigenic structure of authentic virions, and are relatively acid- and heat-stable. norwalk virus (nv), the prototype nov, has been studied extensively, and norwalk virus-like particles (nvlps) produced in insect cells and plants are immunogenic in mic ... | 2010 | 20218858 |
| environmental health aspects of drinking water-borne outbreak due to karst flooding: case study. | climate change may increase the incidence of waterborne diseases due to extreme rainfall events, and consequent microbiological contamination of the water source and supply. as a result of the complexity of the pathways from the surface to the consumer, it is difficult to detect an association between rainfall and human disease. the water supply of a hungarian city, miskolc (174,000 inhabitant), is mainly based on karstic water, a vulnerable underground water body. a large amount of precipitatio ... | 2010 | 20375480 |
| norwalk virus assembly and stability monitored by mass spectrometry. | viral capsid assembly, in which viral proteins self-assemble into complexes of well defined architecture, is a fascinating biological process. although viral structure and assembly processes have been the subject of many excellent structural biology studies in the past, questions still remain regarding the intricate mechanisms that underlie viral structure, stability, and assembly. here we used native mass spectrometry-based techniques to study the structure, stability, and assembly of norwalk v ... | 2010 | 20418222 |
| use of propidium monoazide in reverse transcriptase pcr to distinguish between infectious and noninfectious enteric viruses in water samples. | human enteric viruses can be present in untreated and inadequately treated drinking water. molecular methods, such as the reverse transcriptase pcr (rt-pcr), can detect viral genomes in a few hours, but they cannot distinguish between infectious and noninfectious viruses. since only infectious viruses are a public health concern, methods that not only are rapid but also provide information on the infectivity of viruses are of interest. the intercalating dye propidium monoazide (pma) has been use ... | 2010 | 20472736 |
| identification of cross-reactive norovirus cd4+ t cell epitopes. | immune responses and the components of protective immunity following norovirus infection in humans are poorly understood. although antibody responses following norovirus infection have been partially characterized, t cell responses in humans remain largely undefined. in contrast, t cells have been shown to be essential for viral clearance of mouse norovirus (mnv) infection. in this paper, we demonstrate that cd4(+) t cells secrete gamma interferon (ifn-gamma) in response to stimulation with mnv ... | 2010 | 20573810 |
| quantification of norwalk virus inocula: comparison of endpoint titration and real-time reverse transcription-pcr methods. | human noroviruses (nov) are the leading cause of epidemic acute gastroenteritis. in order to fully characterize features such as persistence and infectious dose, precise quantification of virus concentration is necessary. the purpose of this study was to compare two methods [endpoint titration rt-pcr and quantitative rt-pcr (rt-qpcr)] with respect to quantification of norwalk virus (nv) in inocula made from purified stock suspensions of human fecal specimens. a full-length nv rna transcript was ... | 2010 | 20648618 |
| norwalk virus does not replicate in human macrophages or dendritic cells derived from the peripheral blood of susceptible humans. | human noroviruses are difficult to study due to the lack of an efficient in vitro cell culture system or small animal model. murine norovirus replicates in murine macrophages (mphi) and dendritic cells (dcs), raising the possibility that human novs might replicate in such human cell types. to test this hypothesis, we evaluated dcs and mphi derived from monocyte subsets and cd11c(+) dcs isolated from peripheral blood mononuclear cells of individuals susceptible to norwalk virus (nv) infection. th ... | 2010 | 20667573 |
| sibling-size variation in brown trout salmo trutta in relation to egg size and stream size. | sibling-size variation (ssv), estimated as the coefficient of variation of egg size, was investigated for 13 populations of brown trout salmo trutta. ssv was negatively correlated with mean egg size both at the population and individual levels. after correction for the effect of mean egg size, ssv was also negatively correlated with stream size. these results provide new information about how salmonid ssv can vary at different ecological scales (individual, population and region). the results ar ... | 2009 | 20735629 |
| serological correlate of protection against norovirus-induced gastroenteritis. | norovirus infection is the leading cause of acute nonbacterial gastroenteritis. histoblood group antigens (hbgas) are host susceptibility determinants for norwalk virus (nv) infection. we hypothesized that antibodies that block nv-hbga binding are associated with protection from clinical illness following nv exposure. | 2010 | 20815703 |
| measuring quality of mental health care: a review of initiatives and programs in selected countries. | this review article presents a systematic review of grey literature describing current initiatives that assess the quality of mental health care in 12 countries, as collected by the international initiative for mental health leadership.there have been increased efforts in many countries to develop and implement mental health indicator schemes to measure and monitor the quality of mental health care at the national and subnational level. most mental health indicator sets are part of larger health ... | 2010 | 20840801 |
| an intranasally delivered toll-like receptor 7 agonist elicits robust systemic and mucosal responses to norwalk virus-like particles. | norwalk virus (nv) is an enteric pathogen from the genus norovirus and a major cause of nonbacterial gastroenteritis in humans. nv virus-like particles (vlps) are known to elicit systemic and mucosal immune responses when delivered nasally; however, the correlates of immune protection are unknown, and codelivery with a safe and immunogenic mucosal adjuvant may enhance protective anti-nv immune responses. resiquimod (r848), an imidazoquinoline-based toll-like receptor 7 and/or 8 (tlr7/8) agonist, ... | 2010 | 20962211 |
| inhibition of cellular protein secretion by norwalk virus nonstructural protein p22 requires a mimic of an endoplasmic reticulum export signal. | protein trafficking between the endoplasmic reticulum (er) and golgi apparatus is central to cellular homeostasis. er export signals are utilized by a subset of proteins to rapidly exit the er by direct uptake into copii vesicles for transport to the golgi. norwalk virus nonstructural protein p22 contains a yxφesdg motif that mimics a di-acidic er export signal in both sequence and function. however, unlike normal er export signals, the er export signal mimic of p22 is necessary for apparent inh ... | 2010 | 20976190 |
| adjuvanted intranasal norwalk virus-like particle vaccine elicits antibodies and antibody-secreting cells that express homing receptors for mucosal and peripheral lymphoid tissues. | noroviruses cause significant morbidity and mortality from acute gastroenteritis in all age groups worldwide. | 2010 | 20979455 |
| binding of virus-like particles of norwalk virus to romaine lettuce veins. | noroviruses (nov) annually cause millions of cases of gastrointestinal disease in the united states. nov are associated with raw shellfish outbreaks, particularly oysters, which are thought to bioaccumulate nov particles during the filter-feeding process. nov outbreaks, however, have also been known to occur from other common-source food-borne vehicles, such as lettuce, frozen raspberries, and salad. in this study, we evaluated romaine lettuce as a potential vehicle for nov transmission by testi ... | 2010 | 21037300 |
| individualizing a capstone project: a cruise ship nurse creates a brochure about the norwalk virus. | an ms capstone is a summative academic project where the student is expected to combine personal experience, previous nursing knowledge, and newly acquired graduate nursing skills and integrate them into practice. the authors discuss the challenges of a capstone project from the committee chair and student perspectives. this family nurse practitioner student was a cruise ship nurse who identified a need related to the norwalk virus. the committee chair needed to direct the student through the ca ... | 2011 | 21135680 |
| biodegradable nanogels for oral delivery of interferon for norovirus infection. | norwalk virus (nv) replicon-harboring cells have provided an excellent tool to the development of antivirals. previously we demonstrated that the expression levels of replicon rna and proteins were significantly reduced in the presence of various interferons (ifns) including ifn-α and ifn-γ in a dose-dependent manner in the nv replicon-harboring cells, and suggested that ifns could be therapeutic options for norovirus infection. it was also demonstrated that innate immunity including ifns is cru ... | 2010 | 21144866 |
| chimpanzees as an animal model for human norovirus infection and vaccine development. | noroviruses are global agents of acute gastroenteritis, but the development of control strategies has been hampered by the absence of a robust animal model. studies in chimpanzees have played a key role in the characterization of several fastidious hepatitis viruses, and we investigated the feasibility of such studies for the noroviruses. seronegative chimpanzees inoculated i.v. with the human norovirus strain norwalk virus (nv) did not show clinical signs of gastroenteritis, but the onset and d ... | 2010 | 21173246 |
| spurious polyadenylation of norovirus narita 104 capsid protein mrna in transgenic plants. | noroviruses are members of the family caliciviridae, and cause a highly communicable gastroenteritis in humans. we explored the potential to develop a plant-based vaccine against narita 104 virus, a genogroup ii norovirus. in stably transgenic potato, we obtained very poor expression of narita 104 virus capsid protein (navcp) despite the use of a strong constitutive promoter (dual enhancer 35s) driving the native coding sequence. we identified potentially detrimental sequence motifs that could m ... | 2011 | 21203799 |
| comparative site-directed mutagenesis in the catalytic amino acid triad in calicivirus proteases. | calicivirus proteases cleave the viral precursor polyprotein encoded by open reading frame 1 (orf1) into multiple intermediate and mature proteins. these proteases have conserved histidine (his), glutamic acid (glu) or aspartic acid (asp), and cysteine (cys) residues that are thought to act as a catalytic triad (i.e. general base, acid and nucleophile, respectively). however, is the triad critical for processing the polyprotein? in the present study, we examined these amino acids in viruses repr ... | 2011 | 21204947 |
| clinical development of plant-produced recombinant pharmaceuticals: vaccines, antibodies and beyond. | in the last few years, plants have become an increasingly attractive platform for recombinant protein production. this builds on two decades of research, starting with transgenic approaches to develop oral vaccines in which antigens or therapeutics can be delivered in processed plant biomass, and progressing to transient expression approaches whereby high yields of purified targets are administered parenterally. the advantages of plant-based expression systems include high scalability, low upstr ... | 2011 | 21346417 |
| geminiviral vectors based on bean yellow dwarf virus for production of vaccine antigens and monoclonal antibodies in plants. | expression of recombinant vaccine antigens and monoclonal antibodies using plant viral vectors has developed extensively during the past several years. the approach benefits from high yields of recombinant protein obtained within days after transient delivery of viral vectors to leaves of nicotiana benthamiana, a tobacco relative. modified viral genomes of both rna and dna viruses have been created. geminiviruses such as bean yellow dwarf virus (beydv) have a small, single stranded dna genome th ... | 2011 | 21358270 |
| serological responses to experimental norwalk virus infection measured using a quantitative duplex time-resolved fluorescence immunoassay. | a quantitative duplex time-resolved fluorescence assay (delfia) was developed to measure norwalk virus (nv)-specific iga and igg antibodies simultaneously. the duplex assay showed superior performance by detecting seroconversion following experimental nv infection at an earlier time point than a reference total immunogobulin elisa. | 2011 | 21593238 |
| medical microbiology | the caliciviruses are small, nonenveloped rna viruses that have characteristic cup-shaped depressions on a spherical capsid surface; hence their name, which is derived from calyx or chalice. caliciviruses have a distinctive structure, sometimes described as a star of david, and are also distinctive in their size (27 to 35 nm), in having only a single major polypeptide, and in the functions of the single-stranded rna genome. they produce mucocutaneous and respiratory tract lesions in several anim ... | 1996 | 21413349 |
| common gene therapy viral vectors do not efficiently penetrate sputum from cystic fibrosis patients. | norwalk virus and human papilloma virus, two viruses that infect humans at mucosal surfaces, have been found capable of rapidly penetrating human mucus secretions. viral vectors for gene therapy of cystic fibrosis (cf) must similarly penetrate purulent lung airway mucus (sputum) to deliver dna to airway epithelial cells. however, surprisingly little is known about the rates at which gene delivery vehicles penetrate sputum, including viral vectors used in clinical trials for cf gene therapy. we f ... | 2011 | 21637751 |
| intranasal delivery of norwalk virus-like particles formulated in an in situ gelling, dry powder vaccine. | the development of a vaccine to prevent norovirus infections has been focused on immunization at a mucosal surface, but has been limited by the low immunogenicity of self-assembling norwalk virus-like particles (nv vlps) delivered enterically or at nasal surfaces. nasal immunization, which offers the advantage of ease of immunization, faces obstacles imposed by the normal process of mucociliary clearance, which limits residence time of applied antigens. herein, we describe the use of a dry powde ... | 2011 | 21640778 |
| backbone and side-chain (1)h, (15)n, and (13)c resonance assignments of norwalk virus protease. | norovirus protease cleaves the virus-encoded polyprotein into six mature nonstructural proteins, presenting itself as an essential enzyme for the viral replication as well as an attractive target for the antiviral drug development. a deeper understanding of the structural mechanism of the protease-substrates/inhibitors interactions by means of solution nmr methods would facilitate a rational design of the virus protease inhibitor. we here report the backbone and side-chain resonance assignment o ... | 2011 | 21647610 |
| randomized, double-blinded clinical trial for human norovirus inactivation in oysters by high hydrostatic pressure processing. | contamination of oysters with human noroviruses (hunov) constitutes a human health risk and may lead to severe economic losses in the shellfish industry. there is a need to identify a technology that can inactivate hunov in oysters. in this study, we conducted a randomized, double-blinded clinical trial to assess the effect of high hydrostatic pressure processing (hpp) on norwalk virus (hunov genogroup i.1) inactivation in virus-seeded oysters ingested by subjects. forty-four healthy, positive-s ... | 2011 | 21705552 |
| nucleolin interacts with the feline calicivirus 3' untranslated region and the protease-polymerase ns6 and ns7 proteins, playing a role in virus replication. | cellular proteins play many important roles during the life cycle of all viruses. specifically, host cell nucleic acid-binding proteins interact with viral components of positive-stranded rna viruses and regulate viral translation, as well as rna replication. here, we report that nucleolin, a ubiquitous multifunctional nucleolar shuttling phosphoprotein, interacts with the norwalk virus and feline calicivirus (fcv) genomic 3' untranslated regions (utrs). nucleolin can also form a complex in vitr ... | 2011 | 21680514 |
| serum hemagglutination inhibition activity correlates with protection from gastroenteritis in persons infected with norwalk virus. | a hemagglutination inhibition assay (hai) was developed to assess serum antibody responses following norwalk virus (nv) infection. hai activity increased significantly in individuals experimentally infected with nv (n=18) and correlated with antibody levels measured in a histo-blood group antigen (hbga) blocking assay. pre-challenge hai antibody levels also correlated with protection from the development of gastroenteritis (mann-whitney, p=0.02). hai is another assay suitable for the detection o ... | 2011 | 22190401 |
| characterization and inhibition of norovirus proteases of genogroups i and ii using a fluorescence resonance energy transfer assay. | noroviruses are the major cause of food- or water-borne gastroenteritis outbreaks in humans. the norovirus protease that cleaves a large viral polyprotein to nonstructural proteins is essential for virus replication and an attractive target for antiviral drug development. noroviruses show high genetic diversity with at least five genogroups, gi-gv, of which gi and gii are responsible for the majority of norovirus infections in humans. we cloned and expressed proteases of norwalk virus (gi) and m ... | 2011 | 22200497 |
| bioprocessing of plant-derived virus-like particles of norwalk virus capsid protein under current good manufacture practice regulations. | despite the success in expressing a variety of subunit vaccine proteins in plants and the recent stride in improving vaccine accumulation levels by transient expression systems, there is still no plant-derived vaccine that has been licensed for human use. the lack of commercial success of plant-made vaccines lies in several technical and regulatory barriers that remain to be overcome. these challenges include the lack of scalable downstream processing procedures, the uncertainty of regulatory co ... | 2011 | 22134876 |
| Prestress strengthens the shell of Norwalk virus nanoparticles. | We investigated the influence of the protruding domain of Norwalk virus-like particles (NVLP) on its overall structural and mechanical stability. Deletion of the protruding domain yields smooth mutant particles and our AFM nanoindentation measurements show a surprisingly altered indentation response of these particles. Notably, the brittle behavior of the NVLP as compared to the plastic behavior of the mutant reveals that the protruding domain drastically changes the capsid's material properties ... | 2011 | 21967663 |
| Robust production of virus-like particles and monoclonal antibodies with geminiviral replicon vectors in lettuce. | Pharmaceutical protein production in plants has been greatly promoted by the development of viral-based vectors and transient expression systems. Tobacco and related Nicotiana species are currently the most common host plants for the generation of plant-made pharmaceutical proteins (PMPs). Downstream processing of target PMPs from these plants, however, is hindered by potential technical and regulatory difficulties owing to the presence of high levels of phenolics and toxic alkaloids. Here, we e ... | 2012 | 21883868 |
| Potent inhibition of Norwalk virus by cyclic sulfamide derivatives. | A new class of compounds that exhibit anti-norovirus activity in a cell-based system and embody in their structure a cyclosulfamide scaffold has been identified. The structure of the initial hit (compound 2a, ED(50) 4 µM, TD(50) 50 µM) has been prospected by exploiting multiple points of diversity and generating appropriate structure-activity relationships. | 2011 | 21925886 |
| Norovirus infectivity in humans and persistence in water. | To examine the long-term infectivity of human norovirus in water, 13 study subjects were challenged at different time points with groundwater spiked with the prototype human norovirus, Norwalk virus. Norwalk virus spiked in groundwater remained infectious after storage at room temperature in the dark for 61 days (the last time point tested). The Norwalk virus-seeded groundwater was stored for 1,266 days and analyzed, after RNase treatment, by reverse transcription-quantitative PCR (RT-qPCR) to d ... | 2011 | 21856841 |
| Norovirus vaccine against experimental human Norwalk Virus illness. | Noroviruses cause epidemic and sporadic acute gastroenteritis. No vaccine is available to prevent norovirus illness or infection. | 2011 | 22150036 |
| the stress (of an) epidemic. | we examined the consequences of being exposed to an outbreak of the norwalk virus at a small university. data from 422 undergraduates supported a model in which the experience of symptoms and perceptions of the university's response to the outbreak predicted fear of future contamination. in turn, fear predicted strain and enhanced hygiene practices. results are consistent with a model of disease outbreak as a traumatic stressor, and implications for organizations dealing with disease outbreaks a ... | 2011 | 22281817 |
| an examination of co-infection in acute gastroenteritis and histo-blood group antigens leading to viral infection susceptibility. | the aim of the present study was to evaluate co-infection in the gastrointestinal tract in terms of viruses, bacteria and the abo blood group. we hypothesized that a combination of norovirus (nv) and bacteria in the gastrointestinal tract could affect the likelihood of an individual to contracting nv. histo-blood group antigens (hbgas) are considered to act as receptors that can lead to nv susceptibility. in addition to genetics, co-infection in the gastrointestinal tract may be associated with ... | 2016 | 26998270 |
| norwalk virus minor capsid protein vp2 associates within the vp1 shell domain. | the major capsid protein of norovirus vp1 assembles to form an icosahedral viral particle. despite evidence that the norwalk virus (nv) minor structural protein vp2 is present in infectious virions, the available crystallographic and electron cryomicroscopy structures of nv have not revealed the location of vp2. in this study, we determined that vp1 associates with vp2 at the interior surface of the capsid, specifically with the shell (s) domain of vp1. we mapped the interaction site to amino ac ... | 2013 | 23408637 |
| antiviral activity of a small molecule deubiquitinase inhibitor occurs via induction of the unfolded protein response. | ubiquitin (ub) is a vital regulatory component in various cellular processes, including cellular responses to viral infection. as obligate intracellular pathogens, viruses have the capacity to manipulate the ubiquitin (ub) cycle to their advantage by encoding ub-modifying proteins including deubiquitinases (dubs). however, how cellular dubs modulate specific viral infections, such as norovirus, is poorly understood. to examine the role of dubs during norovirus infection, we used wp1130, a small ... | 2012 | 22792064 |
| chemical derivatives of a small molecule deubiquitinase inhibitor have antiviral activity against several rna viruses. | most antiviral treatment options target the invading pathogen and unavoidably encounter loss of efficacy as the pathogen mutates to overcome replication restrictions. a good strategy for circumventing drug resistance, or for pathogens without treatment options, is to target host cell proteins that are utilized by viruses during infection. the small molecule wp1130 is a selective deubiquitinase inhibitor shown previously to successfully reduce replication of noroviruses and some other rna viruses ... | 2014 | 24722666 |
| immunogenicity and specificity of norovirus consensus gii.4 virus-like particles in monovalent and bivalent vaccine formulations. | noroviruses, a major cause of acute gastroenteritis worldwide, present antigenic diversity that must be considered for the development of an effective vaccine. in this study, we explored approaches to increase the broad reactivity of virus-like particle (vlp) norovirus vaccine candidates. the immunogenicity of a gii.4 "consensus" vlp that was engineered from sequences of three genetically distinct naturally occurring gii.4 strains was examined for its ability to induce cross-reactive immune resp ... | 2012 | 22469864 |
| dna microarray for detection of gastrointestinal viruses. | gastroenteritis is a clinical illness of humans and other animals that is characterized by vomiting and diarrhea and caused by a variety of pathogens, including viruses. an increasing number of viral species have been associated with gastroenteritis or have been found in stool samples as new molecular tools have been developed. in this work, a dna microarray capable in theory of parallel detection of more than 100 viral species was developed and tested. initial validation was done with 10 differ ... | 2014 | 25355758 |