@article{mertens_moore_jaykus_velev_2022, title={Efficacy and Mechanisms of Copper Ion-Catalyzed Inactivation of Human Norovirus br}, volume={8}, ISSN={["2373-8227"]}, DOI={10.1021/acsinfecdis.1c00609}, abstractNote={The antinoroviral effect of copper ions is well known, yet most of this work has previously been conducted in copper and copper alloy surfaces, not copper ions in solution. In this work, we characterized the effects that Cu ions have on human norovirus capsids’ and surrogates’ integrity to explain empirical data, indicating virus inactivation by copper alloy surfaces, and as means of developing novel metal ion-based virucides. Comparatively high concentrations of Cu(II) ions (>10 mM) had little effect on the infectivity of human norovirus surrogates, so we used sodium ascorbate as a reducing agent to generate unstable Cu(I) ions from solutions of copper bromide. We found that significantly lower concentrations of monovalent copper ions (∼0.1 mM) compared to divalent copper ions cause capsid protein damage that prevents human norovirus capsids from binding to cell receptors in vitro and induce a greater than 4-log reduction in infectivity of Tulane virus, a human norovirus surrogate. Further, these Cu(I) solutions caused reduction of GII.4 norovirus from stool in suspension, producing about a 2-log reduction of virus as measured by a reverse transcriptase-quantitative polymerase chain reaction. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) data indicate substantial major capsid protein cleavage of both GI.7 and GII.4 norovirus capsids, and TEM images show the complete loss of capsid integrity of GI.7 norovirus. GII.4 virus-like particles (VLPs) were less susceptible to inactivation by copper ion treatments than GI.7 VLPs based upon receptor binding and SDS-PAGE analysis of viral capsids. The combined data demonstrate that stabilized Cu(I) ion solutions show promise as highly effective noroviral disinfectants in solution that can potentially be utilized at low concentrations for inactivation of human noroviruses.}, number={4}, journal={ACS INFECTIOUS DISEASES}, author={Mertens, Brittany S. and Moore, Matthew D. and Jaykus, Lee-Ann and Velev, Orlin D.}, year={2022}, month={Apr}, pages={855–864} }
 @article{manuel_suther_moore_jaykus_2021, title={Comparison of a one-step real-time RT-PCR and a nested real-time RT-PCR for a genogroup II norovirus reveals differences in sensitivity depending upon assay design and visualization}, volume={16}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0248581}, abstractNote={Human norovirus (NoV) is the leading cause of acute viral gastroenteritis and a major source of foodborne illness. Detection of NoV in food and environmental samples is typically performed using molecular techniques, including real-time reverse transcription polymerase chain reaction (RT-PCR) and less frequently, nested real-time PCR. In this study, we conducted a controlled comparison of two published NoV detection assays: a broadly reactive one-step real-time RT-PCR and a two-step nested real-time PCR assay. A 20% human fecal suspension containing a genogroup II human NoV was serially diluted, genome extracted, and subjected to amplification using the two assays compared via PCR Units. Additional amplicon confirmation was performed by dot blot hybridization using digoxigenin (DIG)-labeled oligonucleotide probes. Both assays displayed similar amplification standard curves/amplification efficiencies; however, the nested assay consistently detected one log10 lower virus. Dot blot hybridization improved the detection limit of the nested real-time PCR by one log10 NoV genome copies but impaired the detection limit of the one-step real-time RT-PCR by one log10 NoV genome copies. These results illustrate the complexities in designing and interpreting molecular techniques having a sufficient detection limit to detect low levels of viruses that might be anticipated in contaminated food and environmental samples.}, number={4}, journal={PLOS ONE}, author={Manuel, Clyde S. and Suther, Cassandra and Moore, Matthew D. and Jaykus, Lee-Ann}, year={2021}, month={Apr} }
 @article{faircloth_moore_stoufer_kim_jaykus_2021, title={Generation of Nucleic Acid Aptamer Candidates against a Novel Calicivirus Protein Target}, volume={13}, ISSN={["1999-4915"]}, DOI={10.3390/v13091716}, abstractNote={Human norovirus is the leading cause of foodborne illness globally. One of the challenges in detecting noroviruses is the identification of a completely broadly reactive ligand; however, all detection ligands generated to date target the viral capsid, the outermost of which is the most variable region of the genome. The VPg is a protein covalently linked to the viral genome that is necessary for replication but hitherto remains underexplored as a target for detection or therapeutics. The purpose of this work was to generate nucleic acid aptamers against human norovirus (Norwalk) and cultivable surrogate (Tulane) VPgs for future use in detection and therapeutics. Eight rounds of positive-SELEX and two rounds of counter-SELEX were performed. Five and eight unique aptamer sequences were identified for Norwalk and Tulane VPg, respectively, all of which were predicted to be stable (∆G < −5.0) and one of which occurred in both pools. All candidates displayed binding to both Tulane and Norwalk VPg (positive:negative > 5.0), and all but two of the candidates displayed very strong binding (positive:negative > 10.0), significantly higher than binding to the negative control protein (p < 0.05). Overall, this work reports a number of aptamer candidates found to be broadly reactive and specific for in vitro-expressed VPgs across genus that could be used for future application in detection or therapeutics. Future work characterizing binding of the aptamer candidates against native VPgs and in therapeutic applications is needed to further evaluate their application.}, number={9}, journal={VIRUSES-BASEL}, author={Faircloth, Jeremy and Moore, Matthew D. and Stoufer, Sloane and Kim, Minji and Jaykus, Lee-Ann}, year={2021}, month={Sep} }
 @article{moore_jaykus_2017, title={A plate-based histo-blood group antigen binding assay for evaluation of human norovirus receptor binding ability}, volume={533}, ISSN={["1096-0309"]}, DOI={10.1016/j.ab.2017.06.012}, abstractNote={Human norovirus is a leading cause of gastroenteritis worldwide. Although two in vitro cultivation methods have been reported, they cannot provide mechanistic insights into viral inactivation. Receptor-binding assays supplement these assays and give insight into capsid integrity. We present a streamlined version of a receptor-binding assay with minimal time-to-result while maintaining accuracy and high throughput. We validate assay performance for physical and chemical inactivation treatments of a norovirus GII.4 capsid. The assay produces a high positive/negative ratio (25.3 ± 4.9) in <2.5 h and has a limit of detection of 0.1 μg/ml capsid. This method is a valuable additional tool for understanding human norovirus inactivation.}, journal={ANALYTICAL BIOCHEMISTRY}, author={Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Sep}, pages={56–59} }
 @article{moore_jaykus_2017, title={Development of a Recombinase Polymerase Amplification Assay for Detection of Epidemic Human Noroviruses}, volume={7}, ISSN={["2045-2322"]}, DOI={10.1038/srep40244}, abstractNote={Abstract Human norovirus is a leading cause of viral gastroenteritis worldwide. Rapid detection could facilitate control, however widespread point-of-care testing is infrequently done due to the lack of robust and portable methods. Recombinase polymerase amplification (RPA) is a novel isothermal method which rapidly amplifies and detects nucleic acids using a simple device in near real-time. An RT-RPA assay targeting a recent epidemic human norovirus strain (GII.4 New Orleans) was developed and evaluated in this study. The assay successfully detected purified norovirus RNA from multiple patient outbreak isolates and had a limit of detection of 3.40 ± 0.20 log 10 genomic copies (LGC), which is comparable to most other reported isothermal norovirus amplification methods. The assay also detected norovirus in directly boiled stool, and displayed better resistance to inhibitors than a commonly used RT-qPCR assay. The assay was specific, as it did not amplify genomes from 9 non-related enteric viruses and bacteria. The assay detected norovirus in some samples in as little as 6 min, and the entire detection process can be performed in less than 30 min. The reported RT-RPA method shows promise for sensitive point-of-care detection of epidemic human norovirus, and is the fastest human norovirus amplification method to date.}, journal={SCIENTIFIC REPORTS}, author={Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Jan} }
 @article{manuel_moore_jaykus_2017, title={Efficacy of a disinfectant containing silver dihydrogen citrate against GI.6 and GII.4 human norovirus}, volume={122}, ISSN={["1365-2672"]}, DOI={10.1111/jam.13331}, abstractNote={Human norovirus is a major public health burden and is resistant to numerous sanitizers and disinfectants. In this study, we tested the efficacy of an antimicrobial product containing a blend of silver ions and citric acid (silver dihydrogen citrate; SDC) against GI.6 and GII.4 HuNoV.}, number={1}, journal={JOURNAL OF APPLIED MICROBIOLOGY}, author={Manuel, C. S. and Moore, M. D. and Jaykus, L. -A.}, year={2017}, month={Jan}, pages={78–86} }
 @article{almand_moore_outlaw_jaykus_2017, title={Human norovirus binding to select bacteria representative of the human gut microbiota}, volume={12}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0173124}, abstractNote={Recent reports describe the ability of select bacterial strains to bind human norovirus, although the specificity of such interactions is unknown. The purpose of this work was to determine if a select group of bacterial species representative of human gut microbiota bind to human norovirus, and if so, to characterize the intensity and location of that binding. The bacteria screened included naturally occurring strains isolated from human stool (Klebsiella spp., Citrobacter spp., Bacillus spp., Enterococcus faecium and Hafnia alvei) and select reference strains (Staphylococcus aureus and Enterobacter cloacae). Binding in PBS was evaluated to three human norovirus strains (GII.4 New Orleans 2009 and Sydney 2012, GI.6) and two surrogate viruses (Tulane virus and Turnip Crinkle Virus (TCV)) using a suspension assay format linked to RT-qPCR for quantification. The impact of different overnight culture media prior to washing on binding efficiency in PBS was also evaluated, and binding was visualized using transmission electron microscopy. All bacteria tested bound the representative human norovirus strains with high efficiency (<1 log10 of input virus remained unbound or <10% unbound and >90% binding efficiency) (p>0.05); there was selective binding for Tulane virus and no binding observed for TCV. Binding efficiency was highest when bacteria were cultured in minimal media (<1 log10 of input virus remained unbound, so >90% bound), but notably decreased when cultured in enriched media (1–3 log10 unbound or 0.01 –<90% bound)) (p<0.05). The norovirus-bacteria binding occurred around the outer cell surfaces and pili structures, without apparent localization. The findings reported here further elucidate and inform the dynamics between human noroviruses and enteric bacteria with implications for norovirus pathogenesis.}, number={3}, journal={PLOS ONE}, author={Almand, Erin A. and Moore, Matthew D. and Outlaw, Janie and Jaykus, Lee-Ann}, year={2017}, month={Mar} }
 @misc{almand_moore_jaykus_2017, title={Norovirus Binding to Ligands Beyond Histo-Blood Group Antigens}, volume={8}, ISSN={["1664-302X"]}, DOI={10.3389/fmicb.2017.02549}, abstractNote={Histo-blood group antigens (HBGAs) are commonly accepted as the cellular receptors for human norovirus. However, some human noroviruses have been found not to bind any HBGA ligand, suggesting potential additional co-factors. Some ligands have been found to bind noroviruses and have the potential to be additional cellular receptors/attachment factors for human norovirus or inhibitors of the HBGA interaction. The studies identifying these mostly characterize different chemical, human, food, or bacterial components and their effect on norovirus binding and infection, although the mechanism of interaction is unknown in many cases. This review seeks to supplement the already well-covered HBGA-norovirus literature by covering non-HBGA human norovirus ligands and inhibitors to provide investigators with a more comprehensive view of norovirus ligands.}, journal={FRONTIERS IN MICROBIOLOGY}, author={Almand, Erin A. and Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Dec} }
 @article{moore_jaykus_2017, title={Recombinase polymerase amplification: a promising point-of-care detection method for enteric viruses}, volume={12}, ISSN={["1746-0808"]}, DOI={10.2217/fvl-2017-0034}, abstractNote={Viral enteric disease imposes a considerable public health and economic burden globally in both humans and livestock. Because enteric viruses are highly transmissible and resistant to numerous control strategies, making early in-field or point-of-care detection is important. There are problems with ligand-based detection strategies (e.g., sensitivity, false positive/negatives) for virus detection. Traditional amplification-based strategies are sensitive, but not as portable or rapid. Recombinase polymerase amplification is a new isothermal technique that utilizes bacterial genome repair enzymes to rapidly amplify target sequences. This report reviews the use of recombinase polymerase amplification for virus detection, showing that the method has favorable fundamental properties supporting its promise for rapid point-of-care detection of enteric viruses.}, number={8}, journal={FUTURE VIROLOGY}, author={Moore, Matthew D. and Jaykus, Lee-Ann}, year={2017}, month={Aug}, pages={421–429} }
 @misc{almand_moore_jaykus_2017, title={Virus-bacteria interactions: An emerging topic in human infection}, volume={9}, number={3}, journal={Viruses-Basel}, author={Almand, E. A. and Moore, M. D. and Jaykus, L. A.}, year={2017} }
 @article{moore_bobay_mertens_jaykus_2016, title={Human Norovirus Aptamer Exhibits High Degree of Target Conformation-Dependent Binding Similar to That of Receptors and Discriminates Particle Functionality}, volume={1}, ISSN={["2379-5042"]}, DOI={10.1128/msphere.00298-16}, abstractNote={Human noroviruses impose a considerable health burden globally. However, study of their inactivation is still challenging with currently reported cell culture models, as discrimination of infectious viral particles is still difficult. Traditionally, the ability of particles to bind putative carbohydrate receptors is conducted as a proxy for infectivity, but these receptors are inconsistent, expensive, and hard to purify/modify. We report a hitherto unexplored property of a different type of ligand, a nucleic acid aptamer, to mimic receptor binding behavior and assess capsid functionality for a selected strain of norovirus. These emerging ligands are cheaper, more stable, and easily synthesized/modified. The previously unutilized characteristic reported here demonstrates the fundamental potential of aptamers to serve as valuable, accessible tools for any microorganism that is difficult to cultivate/study. Therefore, this novel concept suggests a new use for aptamers that is of great value to the microbiological community—specifically that involving fastidious microbes. ABSTRACT Although two in vitro cultivation methods have been reported, discrimination of infectious human norovirus particles for study of viral inactivation is still a challenge, as both rely on reverse transcriptase quantitative PCR. Histo-blood group antigen (HBGA) binding assays serve as a proxy for estimation of infectious particles; however, they are costly and difficult to purify/modify. Some evidence suggests that certain nucleic acid aptamers only bind intact target proteins, thus displaying a high degree of conformation-dependent binding. The objective of this proof-of-concept study was to characterize the degree of conformation-dependent binding a human norovirus aptamer, M6-2, displayed with the capsid of the norovirus GII.4 Sydney (SYV) strain as a model. SYV capsids were exposed to heat, and aptamer, receptor (HBGA), and antibody binding was assessed. M6-2 and the receptor displayed similarly little target sequence-dependent binding (2.0% ± 1.3% and 0.5% ± 1.2% signal, respectively) compared to that of NS14 (26.4% ± 3.9%). The decay rates calculated with M6-2 and the receptor were also not statistically significantly different (P > 0.05), and dynamic light scattering and electron microscopy confirmed these observations. Ligand docking simulations revealed multiple distinct contacts of M6-2 in the N-terminal P1 and P2 domains of the viral capsid, with some residues close to receptor binding residues. These data suggest that single-stranded DNA aptamers like M6-2 display a high degree of target conformation-dependent binding. It is the first time nucleic acid aptamers have had this characteristic utilized and investigated to discern the infectivity status of viral particles, and the data suggest that other aptamers may show promise as valuable ligands in the study of other fastidious microorganisms. IMPORTANCE Human noroviruses impose a considerable health burden globally. However, study of their inactivation is still challenging with currently reported cell culture models, as discrimination of infectious viral particles is still difficult. Traditionally, the ability of particles to bind putative carbohydrate receptors is conducted as a proxy for infectivity, but these receptors are inconsistent, expensive, and hard to purify/modify. We report a hitherto unexplored property of a different type of ligand, a nucleic acid aptamer, to mimic receptor binding behavior and assess capsid functionality for a selected strain of norovirus. These emerging ligands are cheaper, more stable, and easily synthesized/modified. The previously unutilized characteristic reported here demonstrates the fundamental potential of aptamers to serve as valuable, accessible tools for any microorganism that is difficult to cultivate/study. Therefore, this novel concept suggests a new use for aptamers that is of great value to the microbiological community—specifically that involving fastidious microbes.}, number={6}, journal={MSPHERE}, author={Moore, Matthew D. and Bobay, Benjamin G. and Mertens, Brittany and Jaykus, Lee-Ann}, year={2016} }
 @article{manuel_moore_jaykus_2015, title={Destruction of the Capsid and Genome of GII.4 Human Norovirus Occurs during Exposure to Metal Alloys Containing Copper}, volume={81}, ISSN={["1098-5336"]}, DOI={10.1128/aem.00388-15}, abstractNote={ABSTRACT Human norovirus (HuNoV) represents a significant public health burden worldwide and can be environmentally transmitted. Copper surfaces have been shown to inactivate the cultivable surrogate murine norovirus, but no such data exist for HuNoV. The purpose of this study was to characterize the destruction of GII.4 HuNoV and virus-like particles (VLPs) during exposure to copper alloy surfaces. Fecal suspensions positive for a GII.4 HuNoV outbreak strain or GII.4 VLPs were exposed to copper alloys or stainless steel for 0 to 240 min and recovered by elution. HuNoV genome integrity was assessed by reverse transcription-quantitative PCR (RT-qPCR) (without RNase treatment), and capsid integrity was assessed by RT-qPCR (with RNase treatment), transmission electron microscopy (TEM), SDS-PAGE/Western blot analysis, and a histo-blood group antigen (HBGA) binding assay. Exposure of fecal suspensions to pure copper for 60 min reduced the GII.4 HuNoV RNA copy number by ∼3 log10 units when analyzed by RT-qPCR without RNase treatment and by 4 log10 units when a prior RNase treatment was used. The rate of reduction of the HuNoV RNA copy number was approximately proportional to the percentage of copper in each alloy. Exposure of GII.4 HuNoV VLPs to pure-copper surfaces resulted in noticeable aggregation and destruction within 240 min, an 80% reduction in the VP1 major capsid protein band intensity in 15 min, and a near-complete loss of HBGA receptor binding within 8 min. In all experiments, HuNoV remained stable on stainless steel. These results suggest that copper surfaces destroy HuNoV and may be useful in preventing environmental transmission of the virus in at-risk settings.}, number={15}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Manuel, C. S. and Moore, M. D. and Jaykus, L. A.}, year={2015}, month={Aug}, pages={4940–4946} }
 @article{moore_escudero-abarca_suh_jaykus_2015, title={Generation and characterization of nucleic acid aptamers targeting the capsid P domain of a human norovirus GII.4 strain}, volume={209}, ISSN={["1873-4863"]}, DOI={10.1016/j.jbiotec.2015.06.389}, abstractNote={Human noroviruses (NoV) are the leading cause of acute viral gastroenteritis worldwide. Significant antigenic diversity of NoV strains has limited the availability of broadly reactive ligands for design of detection assays. The purpose of this work was to produce and characterize single stranded (ss)DNA aptamers with binding specificity to human NoV using an easily produced NoV target—the P domain protein. Aptamer selection was done using SELEX (Systematic Evolution of Ligands by EXponential enrichment) directed against an Escherichia coli-expressed and purified epidemic NoV GII.4 strain P domain. Two of six unique aptamers (designated M1 and M6-2) were chosen for characterization. Inclusivity testing using an enzyme-linked aptamer sorbent assay (ELASA) against a panel of 14 virus-like particles (VLPs) showed these aptamers had broad reactivity and exhibited strong binding to GI.7, GII.2, two GII.4 strains, and GII.7 VLPs. Aptamer M6-2 exhibited at least low to moderate binding to all VLPs tested. Aptamers significantly (p < 0.05) bound virus in partially purified GII.4 New Orleans outbreak stool specimens as demonstrated by ELASA and aptamer magnetic capture (AMC) followed by RT-qPCR. This is the first demonstration of human NoV P domain protein as a functional target for the selection of nucleic acid aptamers that specifically bind and broadly recognize diverse human NoV strains.}, journal={JOURNAL OF BIOTECHNOLOGY}, author={Moore, Matthew D. and Escudero-Abarca, Blanca I. and Suh, Soo Hwan and Jaykus, Lee-Ann}, year={2015}, month={Sep}, pages={41–49} }
 @article{moore_goulter_jaykus_2015, title={Human Norovirus as a Foodborne Pathogen: Challenges and Developments}, volume={6}, ISSN={["1941-1413"]}, DOI={10.1146/annurev-food-022814-015643}, abstractNote={Human noroviruses (NoVs) are the leading cause of foodborne illness in the United States, and they exact a considerable human and economic burden worldwide. In fact, the many challenging aspects of human NoV have caused some to call it the nearly perfect foodborne pathogen. In this review, a brief overview of NoVs and their genetic structure is provided. Additionally, the challenges and recent developments related to human NoVs regarding viral evolution, transmission, epidemiology, outbreak identification, cultivation, animal and human models, and detection are presented.}, journal={ANNUAL REVIEW OF FOOD SCIENCE AND TECHNOLOGY, VOL 6}, author={Moore, Matthew D. and Goulter, Rebecca M. and Jaykus, Lee-Ann}, year={2015}, pages={411–433} }
 @article{escudero-abarca_suh_moore_dwivedi_jaykus_2014, title={Selection, Characterization and Application of Nucleic Acid Aptamers for the Capture and Detection of Human Norovirus Strains}, volume={9}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0106805}, abstractNote={Human noroviruses (HuNoV) are the leading cause of acute viral gastroenteritis and an important cause of foodborne disease. Despite their public health significance, routine detection of HuNoV in community settings, or food and environmental samples, is limited, and there is a need to develop alternative HuNoV diagnostic reagents to complement existing ones. The purpose of this study was to select and characterize single-stranded (ss)DNA aptamers with binding affinity to HuNoV. The utility of these aptamers was demonstrated in their use for capture and detection of HuNoV in outbreak-derived fecal samples and a representative food matrix. SELEX (Systematic Evolution of Ligands by EXponential enrichment) was used to isolate ssDNA aptamer sequences with broad reactivity to the prototype GII.2 HuNoV strain, Snow Mountain Virus (SMV). Four aptamer candidates (designated 19, 21, 25 and 26) were identified and screened for binding affinity to 14 different virus-like particles (VLPs) corresponding to various GI and GII HuNoV strains using an Enzyme-Linked Aptamer Sorbant Assay (ELASA). Collectively, aptamers 21 and 25 showed affinity to 13 of the 14 VLPs tested, with strongest binding to GII.2 (SMV) and GII.4 VLPs. Aptamer 25 was chosen for further study. Its binding affinity to SMV-VLPs was equivalent to that of a commercial antibody within a range of 1 to 5 µg/ml. Aptamer 25 also showed binding to representative HuNoV strains present in stool specimens obtained from naturally infected individuals. Lastly, an aptamer magnetic capture (AMC) method using aptamer 25 coupled with RT-qPCR was developed for recovery and detection of HuNoV in artificially contaminated lettuce. The capture efficiency of the AMC was 2.5–36% with an assay detection limit of 10 RNA copies per lettuce sample. These ssDNA aptamer candidates show promise as broadly reactive reagents for use in HuNoV capture and detection assays in various sample types.}, number={9}, journal={PLOS ONE}, author={Escudero-Abarca, Blanca I. and Suh, Soo Hwan and Moore, Matthew D. and Dwivedi, Hari P. and Jaykus, Lee-Ann}, year={2014}, month={Sep} }