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Jiao M, Danthi P, Yu Y. Cholesterol-Dependent Membrane Deformation by Metastable Viral Capsids Facilitates Entry. bioRxiv 2024:2024.01.10.575085. [PMID: 38260524 PMCID: PMC10802578 DOI: 10.1101/2024.01.10.575085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Non-enveloped viruses employ unique entry mechanisms to breach and infect host cells. Understanding these mechanisms is crucial for developing antiviral strategies. Prevailing perspective suggests that non-enveloped viruses release membrane lytic peptides to breach host membranes. However, the precise involvement of the viral capsid in this entry remains elusive. Our study presents direct observations elucidating the dynamically distinctive steps through which metastable reovirus capsids disrupt host lipid membranes as they uncoat into partially hydrophobic intermediate particles. Using both live cells and model membrane systems, our key finding is that reovirus capsids actively deform and permeabilize lipid membranes in a cholesterol-dependent process. Unlike membrane lytic peptides, these metastable viral capsids induce more extensive membrane perturbations, including budding, bridging between adjacent membranes, and complete rupture. Notably, cholesterol enhances subviral particle adsorption, resulting in the formation of pores equivalent to the capsid size. This cholesterol dependence is attributed to the lipid condensing effect, particularly prominent at intermediate cholesterol level. Furthermore, our results reveal a positive correlation between membrane disruption extent and efficiency of viral variants in establishing infection. This study unveils the crucial role of capsid-lipid interaction in non-enveloped virus entry, providing new insights into how cholesterol homeostasis influences virus infection dynamics.
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Affiliation(s)
- Mengchi Jiao
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102
| | - Pranav Danthi
- Department of Biology, Indiana University, Bloomington, IN 47405-7102
| | - Yan Yu
- Department of Chemistry, Indiana University, Bloomington, IN 47405-7102
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2
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Bastin G, Gantzer C, Schvoerer E, Sautrey G. The presence of RNA cargo is suspected to modify the surface hydrophobicity of the MS2 phage. Virology 2023; 585:139-144. [PMID: 37343460 DOI: 10.1016/j.virol.2023.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/02/2023] [Accepted: 06/07/2023] [Indexed: 06/23/2023]
Abstract
The surface hydrophobicity of native or engineered non-enveloped viruses and virus-like particles (VLPs) is a key parameter regulating their fate in living and artificial aqueous systems. Its modulation is mainly depending on the structure and environment of particles. Nevertheless, unexplained variations have been reported between structurally similar viruses and with pH. This indicates that some modulating factors of their hydrophobicity remain to be identified. Herein we investigate the potential involvement of RNA cargo in the MS2 phage used as non-enveloped RNA virus model, by examining the SDS-induced electrophoretic mobility shift (SEMS) determined for native MS2 virions and corresponding RNA-free VLPs at various pH. Interestingly, the SEMS of VLPs was larger and more variable from pH 5 to 9 compared to native virions. These observations are discussed in term of RNA-dependent changes in surface hydrophobicity, suggesting that RNA cargo may be a major modulator/regulator of this viral parameter.
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Affiliation(s)
| | | | - Evelyne Schvoerer
- Université de Lorraine, CNRS, LCPME, F-54000, Nancy, France; Laboratoire de Virologie - Microbiologie, Hôpital Universitaire de Nancy, F-54500, Vandœuvre-lès-Nancy, France.
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Frippiat T, Dams L, Wielick C, Delguste C, Ludwig-Begall LF, Art T, Thiry E. In vitro virucidal activity of nebulized citrate-complexed silver nanoparticles against equine herpesvirus-1 and murine norovirus. Virology 2023; 585:232-239. [PMID: 37406580 DOI: 10.1016/j.virol.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/25/2023] [Accepted: 06/05/2023] [Indexed: 07/07/2023]
Abstract
Viruses can be involved in respiratory disorders in horses, with limited therapeutic options. Citrate-complexed silver nanoparticles (C-AgNP) have shown bactericidal properties after in vitro nebulization. The aim of the present study was to assess the virucidal activity of C-AgNP after in vitro instillation or nebulization on equine herpesvirus-1 (EHV-1) and murine norovirus (MNV), the latter used as surrogate for small non-enveloped viruses. Both viruses were instilled or nebulized with C-AgNP of increasing concentrations, and titres were determined via TCID50 method. We demonstrated efficient inactivation of enveloped EHV-1 following instillation and nebulization of C-AgNP (infectivity losses of ≥ three orders of magnitude). While tenacious MNV was inactivated via 2000 ppm C-AgNP instillation, nebulized C-AgNP did not lead to reduction in MNV titres. Nebulization of C-AgNP may represent a novel virucidal therapeutic approach in horses. Further investigations are needed to assess its safety and effective concentrations for in vivo use.
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Affiliation(s)
- Thibault Frippiat
- Equine Sports Medicine Centre, Faculty of Veterinary Medicine, University of Liege, Belgium; Sportpaardenarts - Equine Sports Medicine, Laren, the Netherlands.
| | - Lorène Dams
- Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, University of Liege, Belgium
| | - Constance Wielick
- Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, University of Liege, Belgium
| | - Catherine Delguste
- General Services, FARAH Research Centre, Faculty of Veterinary Medicine, University of Liege, Belgium
| | - Louisa F Ludwig-Begall
- Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, University of Liege, Belgium
| | - Tatiana Art
- Equine Sports Medicine Centre, Faculty of Veterinary Medicine, University of Liege, Belgium
| | - Etienne Thiry
- Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, University of Liege, Belgium
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Sim JY, Chen YC, Hsu WY, Chen WY, Chou Y, Chow JC, Lai YC, Tang HJ, Chen CC, Ho CH, Chang TH. Circulating pediatric respiratory pathogens in Taiwan during 2020: Dynamic change under low COVID-19 incidence. J Microbiol Immunol Infect 2022; 55:1151-1158. [PMID: 35450828 PMCID: PMC9767794 DOI: 10.1016/j.jmii.2022.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/16/2022] [Accepted: 03/24/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND In Taiwan, there were only 799 confirmed COVID-19 cases in 2020. The unique backdrop amidst a pandemic and promotion of nonpharmaceutical interventions generated some distinct changes in the epidemiology of common respiratory pathogens. In this study, we aimed to investigate the dynamic changes in respiratory pathogens in children during 2020. METHODS We performed a retrospective cohort study at a tertiary hospital in southern Taiwan during 2020. Patients aged 0-18 years who visited the pediatric emergency department were enrolled. Children who presented with clinical symptoms (fever or respiratory illness) and received nasopharyngeal swabs for multiplex polymerase chain reaction (PCR) were included in our analysis. We also compared respiratory syncytial virus (RSV) trends from previous years by PCR and lateral flow immunochromatographic assays from 2017 to 2020. RESULTS A total of 120 children were tested. The overall detection rate was 55%. With strengthened restrictions, the detection rate dropped from 70% to 30%. However, non-enveloped viruses (rhinovirus/enterovirus and adenovirus) were in constant circulation. Upon easing prevention measures, the detection rate remained above 60%, and an outbreak of an enveloped virus (RSV and parainfluenza virus) was noted. Compared with 2017-2019, the cyclical RSV epidemic was delayed, with a large surge in late 2020. CONCLUSIONS We observed a constant circulation of non-enveloped viruses when strict nonpharmaceutical interventions were employed and a delayed surge of enveloped viruses during the easing of restrictions. Continuous surveillance and monitoring of the evolutionary dynamics of respiratory viruses is important, while easing restrictions requires balanced judgment.
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Affiliation(s)
- Jun Yi Sim
- Department of Pediatrics, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taiwan
| | - Yu-Chin Chen
- Department of Pediatrics, Chi Mei Medical Center, Chiali, Tainan, Taiwan
| | - Wei-Yun Hsu
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
| | - Wei-Yu Chen
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
| | - Yun Chou
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
| | - Julie Chi Chow
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
| | - Yi-Ching Lai
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
| | - Hung-Jen Tang
- Department of Internal Medicine, Chi Mei Medical Center, Tainan, Taiwan
| | - Chi-Chung Chen
- Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan,Department of Food Science, National Chiayi University, Chiayi, Taiwan
| | - Chung-Han Ho
- Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan,Department of Information Management, Southern Taiwan University of Science and Technology, Tainan, Taiwan
| | - Tu-Hsuan Chang
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan,Corresponding author. Department of Pediatrics, Chi Mei Medical Center No.901, Zhonghua Rd., Yongkang Dist., Tainan City, 710, Taiwan. Fax: +886 6 220 370
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Imai K, Tanaka M, Miyoshi S, Murakami R, Hagi A, Yamagawa S, Sano D. Disinfection efficacy and mechanism of olanexidine gluconate against norovirus. Am J Infect Control 2022; 50:764-771. [PMID: 34864086 DOI: 10.1016/j.ajic.2021.11.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/18/2021] [Accepted: 11/19/2021] [Indexed: 12/26/2022]
Abstract
BACKGROUND The purpose of this study was to evaluate the virucidal activity of a new olanexidine-containing formulation for hand hygiene (olanexidine gluconate hand rub; OLG-HR) against non-enveloped viruses and to understand its mechanism of action. METHODS The virucidal activities of OLG-HR against two strains of caliciviruses and three adenovirus serotypes were evaluated through suspension tests. Also, virus-like particles were used to predict the effect of olanexidine gluconate on virus particle structure. RESULTS The results of suspension tests under conditions with and without interfering substances (1.5% BSA) indicated that OLG-HR had a broad-spectrum effect against non-enveloped viruses, and the virucidal effect was unaffected by organic contaminants. Furthermore, olanexidine inhibited the binding ability of virus-like particles to the binding receptor of human norovirus and increased the aggregation of virus-like particles in a dose-dependent manner. Transmission electron microscopy showed that the morphology of the virus-like particles was affected by exposure to olanexidine, indicating that the protein-denaturing effect of olanexidine gluconate caused the loss of receptor-binding capability of the viral capsid protein. CONCLUSIONS This study suggests that olanexidine gluconate is a potential biological and environmental disinfectant against norovirus and adenovirus.
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Affiliation(s)
- Kaoru Imai
- Naruto Research Institute, Research and Development Center, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan; Department of Frontier Sciences for Advanced Environment, Graduate School of Environmental Studies, Tohoku University, Sendai, Miyagi, Japan
| | - Makoto Tanaka
- Naruto Research Institute, Research and Development Center, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan
| | - Seiji Miyoshi
- Naruto Research Institute, Research and Development Center, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan
| | - Ren Murakami
- Naruto Research Institute, Research and Development Center, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan
| | - Akifumi Hagi
- Naruto Research Institute, Research and Development Center, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan
| | - Sachi Yamagawa
- Naruto Research Institute, Research and Development Center, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan
| | - Daisuke Sano
- Department of Frontier Sciences for Advanced Environment, Graduate School of Environmental Studies, Tohoku University, Sendai, Miyagi, Japan; Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan.
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Michelon W, Zuchi IDP, Reis JG, Matthiensen A, Viancelli A, da Cruz ACC, Silva IT, Fongaro G, Soares HM. Virucidal activity of microalgae extracts harvested during phycoremediation of swine wastewater. Environ Sci Pollut Res Int 2022; 29:28565-28571. [PMID: 34988790 DOI: 10.1007/s11356-021-17912-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/29/2021] [Indexed: 06/14/2023]
Abstract
Phycoremediation of swine wastewater is a promising treatment since it efficiently removes nutrients and contaminants and, simultaneously, its biomass can be harvested and used to obtain a wide range of valuable compounds and metabolites. In this context, biomass microalgae were investigated for the phycoremediation of swine wastewater, and biomass extracts for its virucidal effect against enveloped and non-enveloped viruses. Microalgae were cultivated in a pilot scale bioreactor fed with swine wastewater as the growth substrate. Hexane, dichloromethane, and methanol were used to obtain the microalgae extracts. Extracts were tested for virucidal potential against HSV-1 and HAdV-5. Virucidal assays were conducted at temperatures that emulate environmental conditions (21 °C) and body temperature (37 °C). The maximum production of microalgae biomass reached a concentration of 318.5 ± 23.6 mgDW L-1. The results showed that phycoremediation removed 100% of ammonia-N and phosphate-P, with rates (k1) of 0.218 ± 0.013 and 0.501 ± 0.038 (day-1), respectively. All microalgae extract reduced 100% of the infectious capacity of HSV-1. The microalgae extracts with dichloromethane and methanol showed inhibition activities at the lowest concentration (3.125 µg mL-1). Virucidal assays against HAdV-5 using microalgae extract of hexane and methanol inhibited the infectious capacity of the virus by 70% at all concentrations tested at 37 °C. At a concentration of 12.5 µg mL-1, the dichloromethane microalgae extract reduced 50-80% of the infectious capacity of HAdV-5, also at 37 °C. Overall, the results suggest that the microalgae can be an attractive source of feedstock biomass for the exploration of alternative virucidal compounds.
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Affiliation(s)
- William Michelon
- Department of Chemical Engineering and Food Engineering, Federal University of Santa Catarina, Florianopolis, SC, 88040-700, Brazil.
- Universidade do Contestado, Victor Sopelsa, Concórdia, SC, 3000, 89711-330, Brazil.
| | - Isabella Dai Pra Zuchi
- Department of Microbiology, Immunology and Parasitology, Laboratory of Applied Virology, Federal University of Santa Catarina, Florianopolis, SC, 88040-700, Brazil
| | - Jacqueline Graff Reis
- Department of Microbiology, Immunology and Parasitology, Laboratory of Applied Virology, Federal University of Santa Catarina, Florianopolis, SC, 88040-700, Brazil
| | | | - Aline Viancelli
- Universidade do Contestado, Victor Sopelsa, Concórdia, SC, 3000, 89711-330, Brazil
| | - Ariadne Cristiane Cabral da Cruz
- Department of Microbiology, Immunology and Parasitology, Laboratory of Applied Virology, Federal University of Santa Catarina, Florianopolis, SC, 88040-700, Brazil
- Department of Dentistry, Federal University of Santa Catarina, Florianopolis, SC, Brazil
| | - Izabella Thaís Silva
- Department of Microbiology, Immunology and Parasitology, Laboratory of Applied Virology, Federal University of Santa Catarina, Florianopolis, SC, 88040-700, Brazil
- Department of Pharmaceutical Science, Federal University of Santa Catarina, Florianopolis, SC, 88040-970, Brazil
| | - Gislaine Fongaro
- Department of Microbiology, Immunology and Parasitology, Laboratory of Applied Virology, Federal University of Santa Catarina, Florianopolis, SC, 88040-700, Brazil
| | - Hugo Moreira Soares
- Department of Chemical Engineering and Food Engineering, Federal University of Santa Catarina, Florianopolis, SC, 88040-700, Brazil
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Bagchi P, Liu X, Cho WJ, Tsai B. Lunapark-dependent formation of a virus-induced ER exit site contains multi-tubular ER junctions that promote viral ER-to-cytosol escape. Cell Rep 2021; 37:110077. [PMID: 34879280 DOI: 10.1016/j.celrep.2021.110077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 09/16/2021] [Accepted: 11/09/2021] [Indexed: 10/19/2022] Open
Abstract
Viruses rearrange host membranes to support different entry steps. Polyomavirus simian virus 40 (SV40) reorganizes the endoplasmic reticulum (ER) membrane to generate focus structures that enable virus ER-to-cytosol escape, a decisive infection step. The molecular architecture of the ER exit site that might illuminate why it is ideally suited for membrane penetration is unknown. Here 3D focused ion beam scanning electron microscopy (FIB-SEM) reconstruction reveals that the ER focus structure consists of multi-tubular ER junctions where SV40 preferentially localizes, suggesting that tubular branch points are virus ER-to-cytosol penetration sites. Functional analysis demonstrates that lunapark-an ER membrane protein that typically stabilizes three-way ER junctions-relocates to the ER foci, where it supports focus formation, leading to SV40 ER escape and infection. Our results reveal how a virus repurposes the activity of an ER membrane protein to form a virus-induced ER substructure required for membrane escape and suggest that ER tubular junctions are vulnerable sites exploited by viruses for membrane penetration.
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Affiliation(s)
- Parikshit Bagchi
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA
| | - Xiaofang Liu
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA
| | - Woo Jung Cho
- Biomedical Research Core Facilities, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB, Ann Arbor, MI 48109, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA.
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Abstract
Viruses must navigate the complex endomembranous network of the host cell to cause infection. In the case of a non-enveloped virus that lacks a surrounding lipid bilayer, endocytic uptake from the plasma membrane is not sufficient to cause infection. Instead, the virus must travel within organelle membranes to reach a specific cellular destination that supports exposure or arrival of the virus to the cytosol. This is achieved by viral penetration across a host endomembrane, ultimately enabling entry of the virus into the nucleus to initiate infection. In this review, we discuss the entry mechanisms of three distinct non-enveloped DNA viruses-adenovirus (AdV), human papillomavirus (HPV), and polyomavirus (PyV)-highlighting how each exploit different intracellular transport machineries and membrane penetration apparatus associated with the endosome, Golgi, and endoplasmic reticulum (ER) membrane systems to infect a host cell. These processes not only illuminate a highly-coordinated interplay between non-enveloped viruses and their host, but may provide new strategies to combat non-enveloped virus-induced diseases.
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Affiliation(s)
- Chelsey C Spriggs
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Mara C Harwood
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, United States.
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9
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Abstract
The most widely-used assays for studying viral entry, including infectivity, cofloatation, and cell-cell fusion assays, yield functional information but provide low resolution of individual entry steps. Structural characterization provides high-resolution conformational information, but on its own is unable to address the functional significance of these conformations. Single virion tracking microscopy techniques provide more detail on the intermediate entry steps than infection assays and more functional information than structural methods, bridging the gap between these methods. In addition, single virion approaches also provide dynamic information about the kinetics of entry processes. This chapter reviews single virion tracking techniques and describes how they can be applied to study specific virus entry steps. These techniques provide information complementary to traditional ensemble approaches. Single virion techniques may either probe virion behavior in live cells or in biomimetic platforms. Synthesizing information from ensemble, structural, and single virion techniques ultimately yields a more complete understanding of the viral entry process than can be achieved by any single method alone.
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Affiliation(s)
- Lakshmi Nathan
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA.
| | - Susan Daniel
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA.
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Eggers M, Koburger-Janssen T, Ward LS, Newby C, Müller S. Bactericidal and Virucidal Activity of Povidone-Iodine and Chlorhexidine Gluconate Cleansers in an In Vivo Hand Hygiene Clinical Simulation Study. Infect Dis Ther 2018; 7:235-247. [PMID: 29761329 PMCID: PMC5986686 DOI: 10.1007/s40121-018-0202-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Indexed: 11/29/2022] Open
Abstract
Introduction Standard in vitro and in vivo tests help demonstrate efficacy of hand hygiene products; however, there is no standard in vivo test method for viruses. We investigated the bactericidal and virucidal efficacy of povidone-iodine (PVP-I) 7.5% scalp and skin cleanser, chlorhexidine gluconate (CHG) 4% hand cleanser and the reference hand wash (soft soap) in 15 healthy volunteers following European Standard EN1499 (hygienic hand wash test method for bacteria), which was adapted for virucidal testing. Methods Separate test series were performed for bactericidal (Escherichia coli) and virucidal [murine norovirus (MNV)] testing. After pre-washing and artificial contamination of hands with test organisms, volunteers underwent testing with 3 and 5 mL of each product for contact times of 15, 30 and 60 s according to a Latin-square randomization. The number of test organisms released from fingertips into sampling fluids was assessed before and after hand washing and mean log10 reduction factor (RF) was calculated. RFs (test-reference) were compared using a Wilcoxon–Wilcox multiple comparisons test per EN1499; efficacy was concluded if p ≤ 0.01. Results PVP-I 7.5% and CHG 4% cleansers both passed EN1499 requirements against E. coli, with statistically significantly greater (p ≤ 0.01) mean log10 RFs compared with reference soft soap across all tests (PVP-I: 4.09–5.27; CHG: 4.12–5.22; soap: 2.75–3.11). The experimental design using EN1499 was applicable to testing with MNV as discriminatory and reproducible results were generated. Mean log10 RFs of MNV were statistically significantly greater for PVP-I (1.57–2.57) compared with soft soap (1.24–1.62), while mean log10 RFs with CHG (0.90–1.34) were lower than for soft soap across all tests. Conclusion PVP-I 7.5% cleanser showed superior efficacy against MNV compared to soft soap and CHG 4% cleanser, while both PVP-I and CHG were superior to soft soap against E. coli. The experimental set-up may be applicable to future testing for antiviral hand washes. Funding Mundipharma Manufacturing Pte Ltd. Plain Language Summary Plain language summary available for this article.
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Affiliation(s)
- Maren Eggers
- Labor Prof Gisela Enders MVZ GbR, Stuttgart, Germany
| | | | - Lois S Ward
- Clinical Operations, Mundipharma Research Limited, Cambridge, UK
| | - Craig Newby
- R&D, Mundipharma Manufacturing Pte Ltd, Singapore, Singapore
| | - Stefan Müller
- Pharmacologicial and Translational Science, Mundipharma Research GmbH & Co KG, Limburg, Germany.
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11
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Nangia S, Pattis JG, May ER. Folding a viral peptide in different membrane environments: pathway and sampling analyses. J Biol Phys 2018; 44:195-209. [PMID: 29644513 DOI: 10.1007/s10867-018-9490-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/16/2018] [Indexed: 10/17/2022] Open
Abstract
Flock House virus (FHV) is a well-characterized model system to study infection mechanisms in non-enveloped viruses. A key stage of the infection cycle is the disruption of the endosomal membrane by a component of the FHV capsid, the membrane active γ peptide. In this study, we perform all-atom molecular dynamics simulations of the 21 N-terminal residues of the γ peptide interacting with membranes of differing compositions. We carry out umbrella sampling calculations to study the folding of the peptide to a helical state in homogenous and heterogeneous membranes consisting of neutral and anionic lipids. From the trajectory data, we evaluate folding energetics and dissect the mechanism of folding in the different membrane environments. We conclude the study by analyzing the extent of configurational sampling by performing time-lagged independent component analysis.
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Abstract
An implicit aim in cellular infection biology is to understand the mechanisms how viruses, microbes, eukaryotic parasites, and fungi usurp the functions of host cells and cause disease. Mechanistic insight is a deep understanding of the biophysical and biochemical processes that give rise to an observable phenomenon. It is typically subject to falsification, that is, it is accessible to experimentation and empirical data acquisition. This is different from logic and mathematics, which are not empirical, but built on systems of inherently consistent axioms. Here, we argue that modeling and computer simulation, combined with mechanistic insights, yields unprecedented deep understanding of phenomena in biology and especially in virus infections by providing a way of showing sufficiency of a hypothetical mechanism. This ideally complements the necessity statements accessible to empirical falsification by additional positive evidence. We discuss how computational implementations of mathematical models can assist and enhance the quantitative measurements of infection dynamics of enveloped and non-enveloped viruses and thereby help generating causal insights into virus infection biology.
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Nims RW, Zhou SS. Intra-family differences in efficacy of inactivation of small, non-enveloped viruses. Biologicals 2016; 44:456-62. [PMID: 27473770 DOI: 10.1016/j.biologicals.2016.05.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 05/06/2016] [Accepted: 05/10/2016] [Indexed: 11/16/2022] Open
Abstract
The use of specific model viruses for validating viral purification process steps and for assessing the efficacies of viral disinfectants is based, in part, on the assumption that viral susceptibilities to such treatments will be similar for different members, including different genera, within a given viral family. This assumption is useful in cases where cell-based infectivity assays or laboratory strains for the specific viruses of interest might not exist. There are some documented cases, however, where exceptions to this assumption exist. In this paper, we discuss some of the more striking cases of intra-family differences in susceptibilities to inactivation steps used for downstream viral purification steps in biologics manufacture (e.g. heat inactivation, low pH, and guanidinium hydrochloride inactivation) and to specific viral disinfectants (e.g. alcohols, hydrogen peroxide, and quaternary ammonium-containing disinfectants) that might be employed for facility/equipment disinfection. The results suggest that care should be taken when extrapolating viral inactivation susceptibilities from specific model viruses to different genera or even to different members of the same genus. This should be taken into consideration by regulatory agencies and biologics manufacturers designing viral clearance and facility disinfection validation studies, and developers and evaluators of viral disinfectants.
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Affiliation(s)
- Raymond W Nims
- RMC Pharmaceutical Solutions, Inc., 1851 Lefthand Circle, Suite A, Longmont, CO 80501, USA
| | - S Steve Zhou
- MicroBioTest, A Division of Microbac Laboratories, Inc., 105 Carpenter Drive, Sterling, VA 20164, USA.
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