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development and application of a broadly reactive real-time reverse transcription-pcr assay for detection of murine noroviruses.murine norovirus (mnv) is a viral agent newly identified in laboratory mice and a large number of genetically diverse mnv strains have been reported to date. a broadly reactive taqman-based real-time reverse transcription (rt)-polymerase chain reaction (pcr) assay was developed for mnvs. novel primers and a taqman mgb probe were designed targeting highly conserved sequences among mnv strains, which are located in the open reading frames 1 (orf1)-orf2 junction region. the quantitative range of th ...201020670657
experimental evidence of recombination in murine noroviruses.based on sequencing data, norovirus (nov) recombinants have been described, but no experimental evidence of recombination in novs has been documented. using the murine norovirus (mnv) model, we investigated the occurrence of genetic recombination between two co-infecting wild-type mnv isolates in raw cells. the design of a pcr-based genotyping tool allowed accurate discrimination between the parental genomes and the detection of a viable recombinant mnv (rec mnv) in the progeny viruses. genetic ...201020702654
in vitro effects of pomegranate juice and pomegranate polyphenols on foodborne viral surrogates.pomegranate juice (pj) has gained popularity because of its associated antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. however, its effects against epidemiologically significant foodborne viruses have not been investigated. in the absence of culturable human noroviruses, feline calicivirus (fcv-f9), murine norovirus (mnv-1), and ms2 (ssrna) bacteriophage were used as foodborne viral surrogates. the aim of this research was to study the effects of pj and pomegranate poly ...201020807113
fate of human enteric viruses during dairy manure-based composting.murine norovirus 1 (mnv-1), aichi virus (aiv), and human adenovirus 41 (ad41) were seeded in dairy manure and composted for 60 days, and both the stability of virus genomes and infectious viruses were evaluated. for compost started in late fall, pile temperature reached approximately 54.5 degrees c on day 1 and remained between 55 and 60 degrees c for 3 days. for viral genomes, aiv had an approximate 1.4-log loss of viral genome after 1 day and more than a 3.1-log loss after 2 days; while for mn ...201020819370
evaluation of various methods for recovering human norovirus and murine norovirus from vegetables and ham.we evaluated and optimized each step in an analytical method for detecting norovirus from various foods. we characterized the buffers needed for eluting norovirus from foods such as ham and lettuce. two different concentration methods, polyethylene glycol (peg) precipitation and hollow fiber ultrafiltration (huf), were compared using both murine norovirus (mnv) and human norovirus (hunov). for peg precipitation, an elution buffer containing 3% beef extract (ph 7.1) was more suitable than 0.05 m ...201020828471
antiviral effects of cranberry juice and cranberry proanthocyanidins on foodborne viral surrogates--a time dependence study in vitro.cranberry juice (cj) and cranberry proanthocyanidins (pac) are widely known for their antibacterial, antiviral, and pharmacological activities. the effect of cj and cranberry pac on the infectivity of foodborne viral surrogates, murine norovirus (mnv-1), feline calicivirus (fcv-f9), ms2 (ssrna) bacteriophage, and ϕx-174 (ssdna) bacteriophage after 0 min to 1h at room temperature was evaluated. viruses at titers of ∼5log(10)pfu/ml were mixed with equal volumes of cj at ph 2.6, cj at ph 7.0, 0.30 ...201020832675
inactivation of human and murine norovirus by high-pressure processing.the effect of high hydrostatic pressure (hpp) was evaluated for inactivation of murine norovirus (mnv), a propagable norovirus (nov), and human nov genogroup ii.4. inactivation of mnv was assessed by viral culturing (50% tissue culture infectious dose [tcid(50)]) and real-time reverse-transcription-polymerase chain reaction (rt-qpcr), whereas nov survival was determined only by rt-qpcr. a treatment of 450 mpa for 15 min at 45°c was sufficient to inactivate 6.5 log(10) of infectious mnv in cultur ...201021034235
evaluation of a norovirus detection methodology for soft red fruits.in the present study, a proposed methodology for detection of gi and gii noroviruses (nov) in soft red fruits was evaluated. the murine norovirus-1 (mnv-1), a recently described cultivable nov surrogate was integrated in the detection methodology as full process control, reverse transcription control and real-time pcr internal amplification control. both the performance and robustness of the proposed methodology were analyzed. firstly, the performance of the method was examined by analysis of th ...201021056775
tangential-flow ultrafiltration with integrated inhibition detection for recovery of surrogates and human pathogens from large-volume source water and finished drinking water.tangential-flow ultrafiltration was optimized for the recovery of escherichia coli, enterococcus faecalis, clostridium perfringens spores, bacteriophages ms2 and prd1, murine norovirus, and poliovirus seeded into 100-liter surface water (sw) and drinking water (dw) samples. sw and dw collected from two drinking water treatment plants were then evaluated for human enteric viruses.201021075885
heat inactivation of hepatitis a virus and a norovirus surrogate in soft-shell clams (mya arenaria).the effectiveness of different thermal treatments for inactivating two viruses in clams was evaluated. soft-shell clam digestive glands experimentally contaminated with hepatitis a virus (hav) or murine norovirus (mnv) were heated for 90, 180, or 300 seconds at 85°c or 90°c in glass vials or plastic bags with 200 g of soft-shell clam meat. inactivation was measured by plaque assay and real-time reverse-transcription (rt)-polymerase chain reaction assay. measured inactivation was similar using bo ...201021126194
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 ...201021144866
source water quality effects on monochloramine inactivation of adenovirus, coxsackievirus, echovirus, and murine norovirus.there is a need for more information regarding monochloramine disinfection efficacy for viruses in water. in this study, monochloramine disinfection efficacy was investigated for coxsackievirus b5 (cvb5), echovirus 11 (e11), murine norovirus (mnv), and human adenovirus 2 (hadv2) in one untreated ground water and two partially treated surface waters. duplicate disinfection experiments were completed at ph 7 and 8 in source water at concentrations of 1 and 3 mg/l monochloramine at 5 and 15 °c. the ...201021145573
inactivation of murine norovirus 1, coliphage phix174, and bacillus fragilis phage b40-8 on surfaces and fresh-cut iceberg lettuce by hydrogen peroxide and uv light.in this study, the inactivating properties of liquid hydrogen peroxide (l-h(2)o(2)), vaporized hydrogen peroxide (v-h(2)o(2)), uv light, and a combination of v-h(2)o(2) and uv light were tested on murine norovirus 1 (mnv-1) and bacteriophages (φx174 and b40-8) as models for human noroviruses. disinfection of surfaces was examined on stainless steel discs based on european standard en 13697 (2001). for fresh-produce decontamination, a mixture of the viruses was inoculated onto shredded iceberg le ...201021183630
prevalence of murine norovirus infection in korean laboratory animal facilities.currently, murine noroviruses (mnv) are the most prevalent viral pathogens identified in laboratory animal facilities. while several reports exist concerning the prevalence of mnv in north american research facilities, very few reports are available for other parts of the world, including korea. this study evaluated the prevalence of mnv infection in 745 murine sera collected from 15 animal facilities in korea by enzyme linked immunosorbent assay (elisa). positive cases were subcategorized by mu ...201021187680
inactivation of a human norovirus surrogate by high-pressure processing: effectiveness, mechanism, and potential application in the fresh produce industry.fresh produce is often a high-risk food for norovirus contamination because it can become contaminated at both preharvest and postharvest stages and it undergoes minimal or no processing. currently, there is no effective method to eliminate the viruses from fresh produce. this study systematically investigated the effectiveness of high-pressure processing (hpp) on inactivating murine norovirus (mnv-1), a surrogate for human norovirus, in aqueous medium and fresh produce. we demonstrated that mnv ...201021193662
inactivation of murine norovirus, feline calicivirus and echovirus 12 as surrogates for human norovirus (nov) and coliphage (f+) ms2 by ultraviolet light (254 nm) and the effect of cell association on uv inactivation.to determine inactivation profiles of three human norovirus (nov) surrogate viruses and coliphage ms2 by ultraviolet (uv) irradiation and the protective effect of cell association on uv inactivation.201121214604
comparative efficacy of seven hand sanitizers against murine norovirus, feline calicivirus, and gii.4 norovirus.contaminated hands or inanimate surfaces can act as a source of infection during outbreaks of human norovirus infection. we evaluated the virucidal efficacy of seven hand sanitizers containing various active ingredients, such as ethanol, triclosan, and chlorhexidine, and compared their effectiveness against feline calicivirus (fcv), murine norovirus (mnv), and a gii.4 norovirus fecal extract. we also tested the efficacy of 50, 70, and 90% of ethanol and isopropanol. reduction of viral infectivit ...201021219741
internalization of murine norovirus 1 by lactuca sativa during irrigation.romaine lettuce (lactuca sativa) was grown hydroponically or in soil and challenged with murine norovirus 1 (mnv) under two conditions: one mimicking a severe one-time contamination event and another mimicking a lower level of contamination occurring over time. in each condition, lettuce was challenged with mnv delivered at the roots. in the first case, contamination occurred on day one with 5 × 10(8) reverse transcriptase quantitative pcr (rt-qpcr) u/ml mnv in nutrient buffer, and irrigation wa ...201121296944
evaluation of electropositive filtration for recovering norovirus in water.the virus adsorption-elution (viradel) technique has been widely used in the recovery of various enteric viruses in water, and an electropositive filter such as 1 mds has been commonly applied. however, effective methods of monitoring waterborne norovirus (nov) have not yet been well characterized and optimized. hence, in this study, the viradel technique was evaluated and optimized for effectively detecting nov in water by two commonly used electropositive filters (1mds and nanoceram filter). v ...201121301112
high hydrostatic pressure processing of murine norovirus 1-contaminated oysters inhibits oral infection in stat-1(-/-)-deficient female mice.we have previously demonstrated that high pressure processing (hpp) is effective in preventing in vitro replication of murine norovirus strain 1 (mnv-1), a human norovirus surrogate, in a monocyte cell line following extraction from mnv-1-contaminated oysters. in the present study, the efficacy of hpp to prevent in vivo replication within mice fed hpp-treated mnv-1-seeded oyster extracts was evaluated. oyster homogenate extracts seeded with mnv-1 were given 5-min, 400-mpa (58,016-psi) treatments ...201121333139
evaluation of a norovirus detection methodology for ready-to-eat foods.despite recent norovirus (nov) foodborne outbreaks related to consumption of ready-to-eat (rte) foods, a standardized assay to detect nov in these foods is not available yet. therefore, the robustness of a methodology for nov detection in rte foods was evaluated. the nov detection methodology consisted of direct rna extraction with an eventual concentration step, followed by rna purification and a multiplex rt-qpcr assay for the detection of gi and gii nov and the murine norovirus-1 (mnv-1), the ...201121333370
inactivation of hepatitis a virus and norovirus surrogate in suspension and on food-contact surfaces using pulsed uv light (pulsed light inactivation of food-borne viruses).this study was conducted to evaluate the inactivation of murine norovirus (mnv-1) and hepatitis a virus (hav) by pulsed ultraviolet (uv) light. mnv-1 was used as a model for human norovirus. viral suspensions of about 10(6) pfu/ml were exposed to pulses of uv light for different times and at different distances in a xenon steripulse device (model rs-3000c). inactivation studies were also carried out on 1-cm(2) stainless steel and polyvinyl chloride disks with 10(5) pfu/ml. inactivation of mnv-1 ...201021356466
screening of fruit products for norovirus and the difficulty of interpreting positive pcr results.despite recent norovirus (nov) outbreaks related to consumption of fruit products, little is known regarding the nov load on these foods. therefore, 75 fruit products were screened for nov presence by using an evaluated in-house nov detection methodology consisting of a nov extraction method and a reverse transcription quantitative pcr assay. additionally, the fruit samples were screened for bacterial pathogens and bacterial hygiene indicators. results of the nov screening showed that 18 of 75 s ...201121375879
trisodium phosphate for foodborne virus reduction on produce.human noroviruses (novs) are recognized as the major cause of acute nonbacterial foodborne gastroenteritis outbreaks in both developed and developing countries. they are resistant to most chemical inactivation processes, and can survive in the environment for long periods. the aim of this research was to apply trisodium phosphate (tsp) on spiked produce (lettuce and peppers) for the reduction of foodborne nov surrogates, feline calicivirus (fcv-f9), and murine norovirus (mnv-1). washed and dried ...201121381924
inactivation of a human norovirus surrogate, human norovirus virus-like particles, and vesicular stomatitis virus by gamma irradiation.gamma irradiation is a nonthermal processing technology that has been used for the preservation of a variety of food products. this technology has been shown to effectively inactivate bacterial pathogens. currently, the fda has approved doses of up to 4.0 kgy to control food-borne pathogens in fresh iceberg lettuce and spinach. however, whether this dose range effectively inactivates food-borne viruses is less understood. we have performed a systematic study on the inactivation of a human norovi ...201121441330
simultaneous comparison of murine norovirus, feline calicivirus, coliphage ms2, and gii.4 norovirus to evaluate the efficacy of sodium hypochlorite against human norovirus on a fecally soiled stainless steel surface.abstract free chlorine as hypochlorite is recommended to decontaminate fecally contaminated surfaces to control human norovirus (nov). we evaluated the efficacy of sodium hypochlorite to decontaminate gii.4 nov and three surrogates of human novs, feline calicivirus (fcv), murine norovirus (mnv), and coliphage ms2, on a fecally soiled stainless steel surface. reduction of infectivity of fcv, mnv, and ms2 was measured by plaque assay and the decline of genomic copy numbers of gii.4 nov by reverse ...201121457050
crystal structures of murine norovirus-1 rna-dependent rna polymerase.norovirus is one of the leading agents of gastroenteritis and is a major public health concern. in this study, the crystal structures of recombinant rna-dependent rna polymerase (rdrp) from murine norovirus-1 (mnv-1) and its complex with 5-fluorouracil (5fu) were determined at 2.5 a resolution. crystals with c2 symmetry revealed a dimer with half a dimer in the asymmetric unit and the protein exists predominantly as a monomer in solution in equilibrium with a smaller population of dimers, trimer ...201121471315
grape seed extract for the control of human enteric viruses.grape seed extract (gse) is reported to have many pharmacological benefits, including antioxidant, anti-inflammatory, anticarcinogenic, and antimicrobial properties. however, the effect of this inexpensive rich source of natural phenolic compounds on human enteric viruses has not been well documented. in the present study, the effect of commercial gse, gravinol-s, on the infectivity of human enteric virus surrogates (feline calicivirus, fcv-f9; murine norovirus, mnv-1; bacteriophage ms2) and hep ...201121498749
ozone inactivation of norovirus surrogates on fresh produce.preharvest contamination of produce by foodborne viruses can occur through a variety of agents, including animal feces/manures, soil, irrigation water, animals, and human handling. problems of contamination are magnified by potential countrywide distribution. postharvest processing of produce can involve spraying, washing, or immersion into water with disinfectants; however, disinfectants, including chlorine, have varying effects on viruses and harmful by-products pose a concern. the use of ozon ...201121549058
development of duplex rt-pcr-elisa for the simultaneous detection of hepatitis a virus and hepatitis e virus.this study aimed to develop a specific and sensitive duplex reverse transcription polymerase chain reaction enzyme-linked immunosorbent assay (duplex rt-pcr-elisa) for hepatitis a virus (hav) and hepatitis e virus (hev). duplex rt-pcr-elisa could detect and differentiate hav and hev with specific probes. when elisa technique was used to detect probe-bound rt-pcr products, duplex rt-pcr-elisa could detect as little as 0.1ng/μl hav and hev from clinical samples. human norovirus, enterovirus, polio ...201121565222
survival of human norovirus surrogates in milk, orange, and pomegranate juice, and juice blends at refrigeration (4 °c).fresh fruits, juices, and beverages have been implicated in human noroviral and hepatitis a virus outbreaks. the purpose of this study was to determine the survival of human norovirus surrogates (murine norovirus, mnv-1; feline calicivirus, fcv-f9; and bacteriophage ms2) in juices (orange and pomegranate juices), juice blends (pomegranate and orange juice) and milk over 0, 1, 2, 7, 14, and 21 days at refrigeration (4 °c). juices, juice blends, and milk were inoculated with each virus over 21 day ...201121569952
validation of internal controls for nucleic acid extraction and amplification of enteric viruses in water samples.inhibitors that reduce viral nucleic acid extraction efficiency and interfere with cdna synthesis and/or polymerase activity affect the molecular detection of viruses in aquatic environments. to overcome the significant problem, we developed a methodology for assessing nucleic acid yields and dna amplification efficiencies for environmental water samples. this involved adding particles of adenovirus type 5 and murine norovirus and newly developed primer sharing controls, which are amplified with ...201121602369
enhanced sanitization of a human norovirus surrogate in fresh vegetables and fruits by a combination of surfactants and sanitizers.fruits and vegetables are a major vehicle for transmission of foodborne enteric viruses since they are easily contaminated at pre- and post-harvest stages and they undergo little or no processing. however, commonly used sanitizers are relatively ineffective for removing human norovirus surrogates from fresh produce. in this study, we systematically evaluated the effectiveness of surfactants on sanitization of a human norovirus surrogate, murine norovirus 1 (mnv-1), from fresh produce. we showed ...201121622782
detection of murine norovirus-1 by using tat peptide-delivered molecular beacons.a tat peptide-delivered molecular beacon was developed and utilized to enumerate murine norovirus 1, a human norovirus (nov) surrogate, in raw 264.7 cells. this allowed the detection of a single infective virus within 6 h, a 12-fold improvement in time required for viral detection and quantification compared to that required by the conventional plaque assay.201121652740
viral infection augments nod1/2 signaling to potentiate lethality associated with secondary bacterial infections.secondary bacterial infection is a common sequela to viral infection and is associated with increased lethality and morbidity. however, the underlying mechanisms remain poorly understood. we show that the tlr3/mda5 agonist poly i:c or viral infection dramatically augments signaling via the nlrs nod1 and nod2 and enhances the production of proinflammatory cytokines. enhanced nod1 and nod2 signaling by poly i:c required the tlr3/mda5 adaptors trif and ips-1 and was mediated by type i ifns. mechan ...201121669398
diversity of murine norovirus strains isolated from asymptomatic mice of different genetic backgrounds within a single u.s. research institute.antibody prevalence studies in laboratory mice indicate that murine norovirus (mnv) infections are common, but the natural history of these viruses has not been fully established. this study examined the extent of genetic diversity of murine noroviruses isolated from healthy laboratory mice housed in multiple animal facilities within a single, large research institute- the national institute of allergy and infectious diseases of the national institutes of health (niaid-nih) in bethesda, maryland ...201121738664
electron-beam inactivation of a norovirus surrogate in fresh produce and model systems.norovirus remains the leading cause of foodborne illness, but there is no effective intervention to eliminate viral contaminants in fresh produce. murine norovirus 1 (mnv-1) was inoculated in either 100 ml of liquid or 100 g of food. the inactivation of mnv-1 by electron-beam (e-beam), or high-energy electrons, at varying doses was measured in model systems (phosphate-buffered saline [pbs], dulbecco's modified eagle's medium [dmem]) or from fresh foods (shredded cabbage, diced strawberries). e-b ...201121740718
design and application of nucleic acid standards for quantitative detection of enteric viruses by real-time pcr.synthetic multiple-target rna and dna oligonucleotides were constructed for use as quantification standards for nucleic acid amplification assays for human norovirus genogroup i and ii, hepatitis e virus, murine norovirus, human adenovirus, porcine adenovirus and bovine polyomavirus. this approach overcomes the problems related to the difficulty of obtaining practical quantities of viral rna and dna from these viruses. the quantification capacity of assays using the standards was excellent in ea ...201121765877
time-dependent effects of pomegranate juice and pomegranate polyphenols on foodborne viral reduction.abstract pomegranate juice (pj) and pomegranate polyphenolic extracts (pp) have antiviral effects against hiv-1, influenza, herpes, and poxviruses, and we recently demonstrated their effect against human noroviral surrogates. in the present study, the time-dependent effects of two commercial brands of pj and pp at two concentrations (2 and 4?mg/ml) on the infectivity of foodborne viral surrogates (feline calicivirus fcv-f9, murine norovirus mnv-1, and ms2 bacteriophage) at room temperature for u ...201121777065
lack of effect of murine norovirus infection on a mouse model of bacteria-induced colon cancer.murine norovirus (mnv) is endemic in mouse research facilities in the united states and europe, with a prevalence as high as 58% to 64%. because of mnv's orofecal route of infection, clinically silent persistent infections in some mouse strains, and proclivity for macrophage and dendritic cells, its presence in mouse colonies has potential to alter phenotypes in experimental mouse models, particularly those involving inflammation and immunologic responses. although mnv is subclinical, not causin ...201121819691
eliminating murine norovirus by cross-fostering.murine norovirus (mnv) is a newly discovered and extremely prevalent pathogen of laboratory mouse colonies. mnv causes severe disease in some immunocompromised mouse strains and can cause persistent infections even in immunocompetent mice. despite the fact that immunocompetent mice are generally asymptomatic, the possibility that mnv infection might alter immune responses makes its eradication a potentially useful goal for many facilities. initial attempts by others to use a strategy of testing ...201121838978
critical studies on binding-based rt-pcr detection of infectious noroviruses.attempts were made to discriminate between infectious and non-infectious noroviruses (novs) based on their viral binding properties followed by reverse transcription polymerase chain reaction (rt-pcr). murine norovirus-1 (mnv-1) was employed as a surrogate to test the principle. detection of both infectious and inactivated mnv-1 was investigated by the plaque assay, rt-pcr and binding-based rt-pcrs. the cell line raw 264.7 and the ganglioside gd1a were used as binding receptors respectively in c ...201121843552
Virucidal activity of different alcohols against murine norovirus, a surrogate of human norovirus. 201121862176
effect of food residues on norovirus survival on stainless steel surfaces.in households and food processing plants, minute food residues left behind from improper cleaning may influence the survivability of human norovirus on surfaces. in this study, the survivability of norovirus on desiccated food residue-attached stainless steel coupons was investigated.201121887215
Comparison of chlorine and peroxyacetic-based disinfectant to inactivate Feline calicivirus, Murine norovirus and Hepatitis A virus on lettuce.In recent years, raw fruits and vegetables have frequently been involved in foodborne transmission to humans of enteric viruses, particularly noroviruses and hepatitis A virus (HAV). Although viral contamination can occur during all steps of food processing, primary production is a critical stage on which prevention measures must be focused to minimize the risk of infection to consumers. Postharvest sanitation may be a valid technological solution for decreasing the bacterial load on fresh raw m ...201121924791
hemocytes are sites of enteric virus persistence within oysters.the goal of this study was to determine how enteric viruses persist within shellfish tissues. several lines of novel evidence show that phagocytic blood cells (hemocytes) of eastern oysters (crassostrea virginica) play an important role in the retention of virus particles. our results demonstrated an association of virus contamination with hemocytes but not with hemolymph. live oysters contaminated overnight with hepatitis a virus (hav) and murine norovirus (mnv) had 56% and 80% of extractable v ...201121948840
VPg-Primed RNA Synthesis of Norovirus RNA-Dependent RNA Polymerases by Using a Novel Cell-Based Assay.Molecular studies of human noroviruses (NoV) have been hampered by the lack of a permissive cell culture system. We have developed a sensitive and reliable mammalian cell-based assay for the human NoV GII.4 strain RNA-dependent RNA polymerase (RdRp). The assay is based on the finding that RNAs synthesized by transiently expressed RdRp can stimulate retinoic acid-inducible gene I (RIG-I)-dependent reporter luciferase production via the beta interferon promoter. Comparable activities were observed ...201121994457
comparative murine norovirus studies reveal a lack of correlation between intestinal virus titers and enteric pathology.human noroviruses are significant emerging pathogens, causing the majority of non-bacterial gastroenteritis outbreaks worldwide. the recent discovery of 30 murine norovirus strains is beginning to facilitate a detailed investigation of norovirus pathogenesis. here, we have performed an in vivo comparative analysis of two murine norovirus strains, mnv-1 and mnv-3. in immunocompetent mice, mnv-1 caused modest intestinal pathology whereas mnv-3 was attenuated compared to mnv-1. surprisingly though, ...201122018636
A single method for recovery and concentration of enteric viruses and bacteria from fresh-cut vegetables.Fresh-cut vegetables are prone to be contaminated with foodborne pathogens during growth, harvest, transport and further processing and handling. As most of these products are generally eaten raw or mildly treated, there is an increase in the number of outbreaks caused by viruses and bacteria associated with fresh vegetables. Foodborne pathogens are usually present at very low levels and have to be concentrated (i.e. viruses) or enriched (i.e. bacteria) to enhance their detection. With this aim, ...201222036077
Effect of high hydrostatic pressure processing on norovirus infectivity and genome stability in strawberry puree and mineral water.We report an evaluation of the effect of various combinations of pressures and times on the inactivation of norovirus (NoV) in two types of matrices that are important in NoV transmission: water and soft fruits. The human NoV surrogate murine norovirus was used as the model virus. The effect of HHP on the viral genome was evaluated by using RT real-time PCR (RT-qPCR), and infectivity assay was used to assess effects on the ability of the virus to attach to and replicate in cells. HHP treatments ...201222044732
comparison of reduction in foodborne viral surrogates by high pressure homogenization.with the increasing global spread of human noroviral infections and the emergence of highly virulent noroviral strains, novel inactivation methods are needed to control foodborne outbreaks. high pressure homogenization (hph) is a novel method that can be applied for foodborne virus reduction in fluids being continuously processed. our objective in the present study was to compare the titer reduction by hph between feline calicivirus strain f9 (fcv-f9) and murine norovirus 1 (mnv-1) as surrogate ...201122054183
evaluation of murine norovirus persistence in environments relevant to food production and processing.human norovirus (nov) causes outbreaks of acute gastroenteritis associated with many ready-to-eat foods, including fresh produce. effective inactivation procedures must consider virus survival under conditions of produce production and processing. this study aimed to investigate the persistence of nov in a variety of environments, using murine nov (mnv) as a surrogate for nov. mnv was incubated for up to 42 days at room temperature on stainless steel disks, on lettuce, on soil, and in potable w ...201122054184
Diversity of murine norovirus in wild rodent populations: species-specific associations suggest an ancient divergence.A survey of wild rodent populations has revealed that murine norovirus (MNV) is present and diverse in wild house mice Mus musculus. This virus is genetically similar to MNV infecting show mice and previously described variants circulating in laboratory mice. The detection of MNV in wild mouse populations suggests that MNV infection of laboratory mice and show mice (from which laboratory mice are derived) derives from contact with or their origins from wild mouse progenitors. The survey addition ...201122071511
virucidal efficacy of hydrogen peroxide vapour disinfection.viral contamination of surfaces is thought to be important in transmission. chemical disinfection can be an effective means of intervention, but little is known about the virucidal efficacy of hydrogen peroxide vapour (hpv) against enteric and respiratory viruses.201122153909
characterization of intestinal dendritic cells in murine norovirus infection.we have shown that respiratory viral infections drive allergic disease through dendritic cells, whether gastrointestinal viruses induce allergies is not known. norovirus infections are a major cause of gastroenteritis in humans. we used murine norovirus (mnv) to explore the effect of mnv infection on gastrointestinal conventional dcs (cdcs) and plasmacytoid dcs (pdcs). mnv infection induced disparate effects on cdcs and pdcs in lymphoid tissues of the small intestine and draining mesenteric lymp ...201122162983
Norovirus Regulation of the Innate Immune Response and Apoptosis Occurs via the Product of the Alternative Open Reading Frame 4.Small RNA viruses have evolved many mechanisms to increase the capacity of their short genomes. Here we describe the identification and characterization of a novel open reading frame (ORF4) encoded by the murine norovirus (MNV) subgenomic RNA, in an alternative reading frame overlapping the VP1 coding region. ORF4 is translated during virus infection and the resultant protein localizes predominantly to the mitochondria. Using reverse genetics we demonstrated that expression of ORF4 is not requir ...201122174679
chlorine treatment to inactivate norovirus on food contact surfaces.this study was conducted to determine the concentration and optimal treatment time of chlorine for reducing feline calicivirus (fcv) and murine norovirus (mnv) as surrogates of norovirus (nov) on stainless steel surfaces and to develop a predictive inactivation method using a response surface methodology. the reduction levels of fcv vr-782 and mnv on stainless steel surfaces after treatment with various concentrations of chlorine (0 to 5,000 ppm) for various times (0 to 5 min) were measured. th ...201222221376
protruding domain of capsid protein is necessary and sufficient to determine murine norovirus replication and pathogenesis in vivo.human noroviruses (hunovs) are the major cause of epidemic, nonbacterial gastroenteritis worldwide. due to the lack of a tractable model system and the inability to grow hunovs in cell culture, factors required for the norovirus (nov) life cycle and pathogenesis in the host remain largely unknown. the discovery of murine norovirus (mnv) and the development of reverse-genetics systems for this virus provide an opportunity to study these aspects of nov infection in vitro and in vivo. previous stud ...201222258242
evaluation of methods measuring the capsid integrity and/or functions of noroviruses by heat inactivation.attempts were made to evaluate methods measuring the capsid integrity and/or functions of noroviruses (novs) following heat treatment. intact viruses (murine norovirus-1 [mnv-1] and human nov gii.4), virus like particles (vlps) and p particles (expressed in vitro from the protruding domain of the viral capsid) of novs were used in this study. following heat treatment, no significant difference of viral titer of mnv-1 versus nov gii.4 was observed by rnase one rt-pcr or cell-binding rt-pcr, altho ...201222266875
effect of high hydrostatic pressure on murine norovirus in manila clams.eating raw or insufficiently cooked bivalve molluscs contaminated with human noroviruses (nvs) can result in acute cases of gastroenteritis in humans. manila clams (ruditapes philippinarum) are particularly prone to exposure to nvs due to the brackish environment in which they are farmed which is known to be susceptible to human faecal contamination. high hydrostatic pressure processing (hhp) is a food treatment technique that has been shown to inactivate nv.201222268557
structural basis for broad detection of genogroup ii noroviruses by a monoclonal antibody that binds to a site occluded in the viral particle.human noroviruses are genetically and antigenically highly divergent. monoclonal antibodies raised in mice against one kind of norovirus virus-like particle (vlp), however, were found to have broad recognition. in this study, we present the crystal structure of the antigen-binding fragment (fab) for one of these broadly reactive monoclonal antibodies, 5b18, in complex with the capsid-protruding domain from a genogroup ii genotype 10 (gii.10) norovirus at 3.3-å resolution and, also, the cryo-elec ...201222278249
inactivation of norovirus surrogates on surfaces and raspberries by steam-ultrasound treatment.human disease outbreaks caused by norovirus (nov) following consumption of contaminated raspberries are an increasing problem. an efficient method to decontaminate the fragile raspberries and the equipment used for processing would be an important step in ensuring food safety. a potential surface treatment that combines pressurized steam and high-power ultrasound (steam-ultrasound) was assessed for its efficacy to inactivate human nov surrogates: coliphage (ms2), feline calicivirus (fcv), and mu ...201222289601
evaluation of four antiseptics using a novel murine norovirus.we isolated a novel murine norovirus (mnv), mt30-2 strain, from feces of conventional mice in japan to evaluate the virucidal activity of four antiseptics. the mnv mt30-2 strain was inactivated by as little as 0.2% (w/v) povidone-iodine (pvp-i) and 0.1% (w/v) sodium hypochlorite (naocl) treatment as determined by a novel plaque assay. importantly, pvp-i reduced the mnv titer by 4 log(10) within 15 s of exposure. the other two antiseptics, benzethonium chloride (bec) and chlorhexidine gluconate ( ...201222293670
mouse norovirus 1 utilizes the cytoskeleton network to establish localization of the replication complex proximal to the microtubule organizing center.human noroviruses (family caliciviridae) are the leading cause of nonbacterial gastroenteritis worldwide. although human noroviruses are significant enteric pathogens, there exists no reliable vaccine or therapy to treat infected individuals. to date, attempts to cultivate human noroviruses within the laboratory have met with little success; however, the related murine norovirus mouse norovirus 1 (mnv-1) has provided an ideal model system to study norovirus replication due to the ease with which ...201222301146
removal and transfer of viruses on food contact surfaces by cleaning cloths.contamination of food contact surfaces with pathogens is considered an important vehicle for the indirect transmission of food-borne diseases. five different cleaning cloths were assessed for the ability to remove viruses from food contact surfaces (stainless steel surface and nonporous solid surface) and to transfer viruses back to these surfaces. cleaning cloths evaluated include two different cellulose/cotton cloths, one microfiber cloth, one nonwoven cloth, and one cotton terry bar towel. fo ...201222327573
murine norovirus increases atherosclerotic lesion size and macrophages in ldlr(-/-) mice.murine norovirus (mnv) is prevalent in rodent facilities in the united states. because mnv has a tropism for macrophages and dendritic cells, we hypothesized that it may alter phenotypes of murine models of inflammatory diseases, such as obesity and atherosclerosis. we examined whether mnv infection influences phenotypes associated with diet-induced obesity and atherosclerosis by using ldlr(-/-) mice. male ldlr(-/-) mice were maintained on either a diabetogenic or high-fat diet for 16 wk, inocul ...201122330248
hygienic monitoring of mongolian gerbils: which mouse viruses should be included?the mongolian gerbil (meriones unguiculatus) serves as an animal model for a wide range of diseases. a practical limitation in its use is the definition of the hygienic status, as not much is known about viruses that potentially infect gerbils and might be transmitted to other rodents. as successful re-derivation was recently described for gerbils, we now aimed at investigating which mouse viruses induce seroconversion in gerbils and might be transmitted to mice. gerbils were inoculated with vir ...201222334874
crystal structures of murine norovirus-1 rna-dependent rna polymerase in complex with 2-thiouridine or ribavirin.murine norovirus-1 (mnv-1) shares many features with human norovirus (hunov) and both are classified within the norovirus genus of caliciviridae family. mnv-1 is used as the surrogate for hunov research since it is the only form that can be grown in cell culture. hunov and mnv-1 rna dependent rna polymerase (rdrp) proteins with the sequence identity of 59% show essentially identical conformations. here we report the first structural evidence of 2-thiouridine (2tu) or ribavirin binding to mnv-1 r ...201222341781
inherent structural disorder and dimerisation of murine norovirus ns1-2 protein.human noroviruses are highly infectious viruses that cause the majority of acute, non-bacterial epidemic gastroenteritis cases worldwide. the first open reading frame of the norovirus rna genome encodes for a polyprotein that is cleaved by the viral protease into six non-structural proteins. the first non-structural protein, ns1-2, lacks any significant sequence similarity to other viral or cellular proteins and limited information is available about the function and biophysical characteristics ...201222347381
new interventions against human norovirus: progress, opportunities, and challenges.human norovirus (hunov) is the leading causative agent of foodborne disease outbreaks worldwide. hunov is highly stable, contagious, and only a few virus particles can cause illness. however, hunov is difficult to study because of the lack of an efficient in vitro cell culture system or a small animal model. to date, there is very limited information available about the biology of hunov, with most data coming from the study of surrogates, such as hunov virus-like particle (vlp), murine norovirus ...201122385167
critical review of norovirus surrogates in food safety research: rationale for considering volunteer studies.the inability to propagate human norovirus (nov) or to clearly differentiate infectious from noninfectious virus particles has led to the use of surrogate viruses, like feline calicivirus (fcv) and murine norovirus-1 (mnv), which are propagatable in cell culture. the use of surrogates is predicated on the assumption that they generally mimic the viruses they represent; however, studies are proving this concept invalid. in direct comparisons between fcv and mnv, their susceptibility to temperatur ...201122408689
effect of temperature, ph, and nacl on the inactivation kinetics of murine norovirus.we investigated the resistance of murine norovirus (mnv) and coliphage ms2, a culturable human norovirus surrogate, to temperature, salt, and ph. virus inactivation was measured by plaque, real-time taqman reverse transcription (rt) pcr, and long-template rt-pcr assays. both mnv and ms2 were rapidly inactivated at temperatures above 60°c. similarly, mnv tolerated low salt concentrations (0.3% nacl) to a greater degree than high salt concentrations (3.3 to 6.3% nacl). mnv was relatively resistant ...201222410228
structure-based inhibition of norovirus rna-dependent rna polymerases.caliciviridae are rna viruses with a single-stranded, positively oriented polyadenylated genome, responsible for a broad spectrum of diseases such as acute gastroenteritis in humans. recently, analyses on the structures and functionalities of the rna-dependent rna polymerase (rdrp) from several caliciviruses have been reported. the rdrp is predicted to play a key role in genome replication, as well as in synthesis and amplification of additional subgenomic rna. starting from the crystal structur ...201222446684
using limes and synthetic psoralens to enhance solar disinfection of water (sodis): a laboratory evaluation with norovirus, escherichia coli, and ms2.we investigated the use of psoralens and limes to enhance solar disinfection of water (sodis) using an uv lamp and natural sunlight experiments. sodis conditions were replicated using sunlight, 2 l polyethylene terephthalate (pet) bottles, and tap water with escherichia coli, ms2 bacteriophage, and murine norovirus (mnv). psoralens and lime acidity both interact synergistically with uv radiation to accelerate inactivation of microbes. escherichia coli was ablated > 6.1 logs by sodis + lime slurr ...201222492137
development of a reverse-genetics system for murine norovirus 3: long-term persistence occurs in the caecum and colon.human noroviruses (hunov) are a major cause of viral gastroenteritis worldwide, yet, due to the inability to propagate hunov in cell culture, murine norovirus (mnv) is typically used as a surrogate to study norovirus biology. mnv-3 represents an attractive strain to study norovirus infections in vivo because it establishes persistence in wild-type mice, yet causes symptoms resembling gastroenteritis in immune-compromised stat1(-/-) mice. the lack of reverse-genetics approaches to recover genetic ...201222495235
nondegradative role of atg5-atg12/ atg16l1 autophagy protein complex in antiviral activity of interferon gamma.host resistance to viral infection requires type i (α/β) and ii (γ) interferon (ifn) production. another important defense mechanism is the degradative activity of macroautophagy (herein autophagy), mediated by the coordinated action of evolutionarily conserved autophagy proteins (atg). we show that the atg5-atg12/atg16l1 protein complex, whose prior known function is in autophagosome formation, is required for ifnγ-mediated host defense against murine norovirus (mnv) infection. importantly, the ...201222520467
persistence and transferability of noroviruses on and between common surfaces and foods.human noroviruses (hunov) are the leading cause of foodborne disease, and poor personal hygiene practices of infected workers are the most common mode of contamination. the purpose of this study was to characterize the persistence and transferability of representative noroviruses norwalk virus (nv), snow mountain virus (smv), and murine norovirus 1 (mnv-1) on and between solid surfaces and foods. changes in virus concentration on artificially inoculated solid surfaces (stainless steel, ceramic, ...201222564943
inactivation of feline calicivirus and murine norovirus during dongchimi fermentation.among the traditional fermented vegetables in korea, dongchimi is a type of kimchi with a large water base. we aimed to investigate the survival of norovirus surrogates during dongchimi fermentation. dongchimi spiked with feline calicivirus (fcv) or murine norovirus (mnv) was prepared following a traditional recipe. dongchimi was initially fermented at room temperature overnight and then kept at 4 °c. the number of lactic acid bacteria, ph, acidity, and virus titer were measured 0, 1, 2, 3, 5, 7 ...201222608225
comparison of two extraction methods for the detection of hepatitis a virus in semi-dried tomatoes and murine norovirus as a process control by duplex rt-qpcr.enteric viruses are important agents of foodborne diseases. due to their low infectious doses and low concentrations in food samples, an efficient and rapid virus concentration method is required for routine control. because of the absence of a reliable cell culture method for most of the enteric viruses involved in outbreaks, reverse transcription quantitative real-time pcr (rt-qpcr) is now widely used for the detection of rna viruses in food samples. one of the general requirements for viral d ...201222608230
development of a strand specific real-time rt-qpcr assay for the detection and quantitation of murine norovirus rna.murine norovirus (mnv), currently the only norovirus that efficiently replicates in cell culture, is often used as a model system to understand the molecular mechanisms of norovirus replication. mnv is a single stranded positive sense rna virus of the caliciviridae family. replication of mnv involves the synthesis of both full length genomic and sub-genomic rnas. the replication of these rnas involves the synthesis of negative strand intermediates. to understand the molecular mechanism of rna re ...201222626565
duplex rt-qpcr for the detection of hepatitis e virus in water, using a process control.human hepatitis e virus (hev) causes acute hepatitis in humans, predominantly by contamination of food and water. hev, in particular genotype iii, is currently considered to be an emerging pathogen in industrialized countries. because of the low infectious dose, an efficient and rapid virus concentration method is required to detect low amounts of hev in food and water samples for routine control. because of the absence of a reliable cell culture method for the main enteric viruses most involved ...201222633799
high-pressure inactivation of human norovirus virus-like particles provides evidence that the capsid of human norovirus is highly pressure resistant.human norovirus (nov) is the leading cause of nonbacterial acute gastroenteritis epidemics worldwide. high-pressure processing (hpp) has been considered a promising nonthermal processing technology to inactivate food- and waterborne viral pathogens. due to the lack of an effective cell culture method for human nov, the effectiveness of hpp in inactivating human nov remains poorly understood. in this study, we evaluated the effectiveness of hpp in disrupting the capsid of human nov based on the s ...201222635990
novel murine norovirus-like genes in wild rodents in japan.novel murine norovirus (mnv)-like sequences were detected in 7 (14.9%) of 47 fecal and intestinal samples obtained from wild rodents in japan. sequencing and genetic analyses of the 7 mnv-like genes, 6 derived from apodemus speciosus and 1 from rattus rattus, suggested that these sequences form a cluster distinct from known mnv within genogroup v and differed even among clusters of wild rodents. considering these results, mnv might be genetically diverse depending on the host species or distribu ...201222673564
structure of a murine norovirus ns6 protease-product complex revealed by adventitious crystallisation.murine noroviruses have emerged as a valuable tool for investigating the molecular basis of infection and pathogenesis of the closely related human noroviruses, which are the major cause of non-bacterial gastroenteritis. the replication of noroviruses relies on the proteolytic processing of a large polyprotein precursor into six non-structural proteins (ns1-2, ns3, ns4, ns5, ns6(pro), ns7(pol)) by the virally-encoded ns6 protease. we report here the crystal structure of mnv ns6(pro), which has b ...201222685603
using propidium monoazide to distinguish between viable and nonviable bacteria, ms2 and murine norovirus.the ability to distinguish between viable and/or infectious micro-organisms and inactivated cells is extremely important for correctly performing microbial risk assessments. in this study, we evaluated whether propidium monoazide (pma)-qpcr could distinguish between viable and nonviable bacteria and viruses.201222690653
internalization and dissemination of human norovirus and animal caliciviruses in hydroponically grown romaine lettuce.fresh produce is a major vehicle for the transmission of human norovirus (nov) because it is easily contaminated during both pre- and postharvest stages. however, the ecology of human nov in fresh produce is poorly understood. in this study, we determined whether human nov and its surrogates can be internalized via roots and disseminated to edible portions of the plant. the roots of romaine lettuce growing in hydroponic feed water were inoculated with 1 × 10(6) rna copies/ml of a human nov genog ...201222729543
reverse genetics mediated recovery of infectious murine norovirus.human noroviruses are responsible for most cases of human gastroenteritis (ge) worldwide and are recurrent problem in environments where close person-to-person contact cannot be avoided (1, 2). during the last few years an increase in the incidence of outbreaks in hospitals has been reported, causing significant disruptions to their operational capacity as well as large economic losses. the identification of new antiviral approaches has been limited due to the inability of human noroviruses to c ...201222760450
comparative inactivation of murine norovirus, human adenovirus, and human jc polyomavirus by chlorine in seawater.viruses excreted by humans affect the commercial and recreational use of coastal water. shellfish produced in contaminated waters have been linked to many episodes and outbreaks of viral gastroenteritis, as well as other food-borne diseases worldwide. the risk can be reduced by appropriate treatment following harvesting and by depuration. the kinetics of inactivation of murine norovirus 1 and human adenovirus 2 in natural and artificial seawater by free available chlorine was studied by quantify ...201222773637
norovirus rna synthesis is modulated by an interaction between the viral rna-dependent rna polymerase and the major capsid protein, vp1.using a cell-based assay for rna synthesis by the rna-dependent rna polymerase (rdrp) of noroviruses, we previously observed that vp1, the major structural protein of the human gii.4 norovirus, enhanced the gii.4 rdrp activity but not that of the related murine norovirus (mnv) or other unrelated rna viruses (c. v. subba-reddy, i. goodfellow, and c. c. kao, j. virol. 85:13027-13037, 2011). here, we examine the mechanism of vp1 enhancement of rdrp activity and the mechanism of mouse norovirus repl ...201222787222
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 ...201222792064
favipiravir (t-705) inhibits in vitro norovirus replication.human noroviruses are the primary cause of foodborne gastroenteritis. potent and safe inhibitors are needed for the treatment/prophylaxis of norovirus infections. we demonstrate that favipiravir [t-705, a drug in advanced clinical development for the treatment of infections with the influenza virus] inhibits in vitro murine norovirus replication. time-of-drug addition studies reveal that t-705 exerts its activity at a time-point that coincides with onset of viral rna synthesis, which is in line ...201222809499
comparison of elisa attachment and infectivity assays for murine norovirus.human noroviruses cause approximately 58% of foodborne illnesses in the usa. recent studies have shown norovirus attachment to the carbohydrates moieties of host cellular receptors. using murine norovirus (mnv) as a surrogate, an elisa method was utilized to assess attachment through binding to host cell receptors; mnv attachment was correlated to infectivity determined by plaque assay. elisa plates were coated with porcine gastric mucin and untreated, heat-, high pressure-, ozone- and uv-treate ...201222820074
effectiveness of chitosan on the inactivation of enteric viral surrogates.chitosan is known to have bactericidal and antifungal activity. although human noroviruses are the leading cause of non-bacterial gastroenteritis, information on the efficacy of chitosan against foodborne viruses is very limited. the objective of this work was to determine the effectiveness of different molecular weight chitosans against the cultivable human norovirus and enteric virus surrogates, feline calicivirus, fcv-f9, murine norovirus, mnv-1, and bacteriophages, ms2 and phix174. five puri ...201222850374
human norovirus transfer to stainless steel and small fruits during handling.human noroviruses (novs) cause an estimated 58% of foodborne illnesses in the united states annually. the majority of these outbreaks are due to contamination by food handlers. the objective of this study was to quantify the transfer rate and degree of contamination that occurs on small fruits (blueberries, grapes, and raspberries) and food contact surfaces (stainless steel) when manipulated with nov-contaminated hands. human novs (genogroups i and ii [gi and gii]) and murine norovirus (mnv-1) w ...201222856567
efficacy of a levulinic acid plus sodium dodecyl sulfate-based sanitizer on inactivation of human norovirus surrogates.human noroviruses are the most common etiologic agent of foodborne illness in the united states. the inability to culture human noroviruses in the laboratory necessitates the use of surrogate viruses such as murine norovirus (mnv-1) and feline calicivirus (fcv) for inactivation studies. in this study, a novel sanitizer of organic acid (levulinic acid) plus the anionic detergent sodium dodecyl sulfate (sds) was evaluated. viruses were treated with levulinic acid (0.5 to 5%), sds (0.05 to 2%), or ...201222856583
[possibilities and the assignments for infection control of norovirus: the verification and the limit of inactivation efficacy by surrogate viruses].norovirus (nov) was isolated from the feces of patients were infected during the outbreak of enteritis in ohio in the early 1970s. subsequent experimental studies on volunteers proved that nov was the enteric virus that caused diarrhea, vomiting, and fever. however, the culture of nov has been unsuccessful, because the mechanism of nov propagating in cells, nov infection routes, and methods for preventing nov infection are unclear. therefore, from the 1980s, feline calicivirus (fcv), which is cu ...201222894060
inactivation of human norovirus surrogates by benzalkonium chloride, potassium peroxymonosulfate, tannic acid, and gallic acid.novel methods to effectively disinfect contact surfaces and prevent human norovirus transmission are essential. the effect of benzalkonium chloride (bac), potassium peroxymonosulfate (kpms), tannic acid (ta), and gallic acid (ga) on enteric virus surrogates, murine norovirus (mnv-1), feline calicivirus (fcv-f9), and bacteriophage ms2 was studied. viruses at high (∼7 log₁₀ pfu/ml) or low (∼5 log₁₀ pfu/ml) titers were mixed with equal volumes of bac (0.2, 0.5, and 1 mg/ml), kpms (5, 10, and 20 mg/ ...201222897744
effect of grape seed extract on human norovirus gii.4 and murine norovirus 1 in viral suspensions, on stainless steel discs, and in lettuce wash water.the anti-norovirus (anti-nov) effect of grape seed extract (gse) was examined by plaque assay for murine norovirus 1 (mnv-1), cell-binding reverse transcription-pcr for human nov gii.4, and saliva-binding enzyme-linked immunosorbent assay for human nov gii.4 p particles, with or without the presence of interfering substances (dried milk and lettuce extract). gse at 0.2 and 2 mg/ml was shown to reduce the infectivity of mnv-1 (>3-log pfu/ml) and the specific binding ability of nov gii.4 to caco-2 ...201222904060
antiviral activity of nucleoside analogues against norovirus.norovirus (nov) is the leading cause of epidemic gastroenteritis worldwide. the lack of a cell culture has significantly hampered the development of effective therapies against human nov. clinically approved nucleoside and non-nucleoside analogues have been used successfully against rna viruses.201222910194
high-resolution functional profiling of the norovirus genome.human noroviruses (hunov) are a major cause of nonbacterial gastroenteritis worldwide, yet details of the life cycle and replication of hunov are relatively unknown due to the lack of an efficient cell culture system. studies with murine norovirus (mnv), which can be propagated in permissive cells, have begun to probe different aspects of the norovirus life cycle; however, our understanding of the specific functions of the viral proteins lags far behind that of other rna viruses. genome-wide fun ...201222915807
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