Plaque Assay for Bacteriophage

Enteric viruses in drinking water supplies

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0080 ◽

2002 ◽

Vol 2 (3) ◽

pp. 17-22

Author(s):

A.P. Wyn-Jones ◽

J. Watkins ◽

C. Francis ◽

M. Laverick ◽

J. Sellwood

Keyword(s):

Drinking Water ◽

Heavy Rainfall ◽

Liquid Culture ◽

Plaque Assay ◽

Enteric Viruses ◽

Enteric Virus ◽

The Other ◽

Raw Water ◽

Rt Pcr ◽

Water Supplies

Two rural spring drinking water supplies were studied for their enteric virus levels. In one, serving about 30 dwellings, the water was chlorinated before distribution; in the other, which served a dairy and six dwellings the water was not treated. Samples of treated (40 l) and untreated (20 l) water were taken under normal and heavy rainfall conditions over a six weeks period and concentrated by adsorption/elution and organic flocculation. Infectious enterovirus in concentrates was detected in liquid culture and enumerated by plaque assay, both in BGM cells, and concentrates were also analysed by RT-PCR. Viruses were found in both raw water supplies. Rural supplies need to be analysed for viruses as well as bacterial and protozoan pathogens if the full microbial hazard is to be determined.

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ACIS, A Novel KepTide™, Binds to ACE-2 Receptor and Inhibits the Infection of SARS-CoV2 Virus in vitro in Primate Kidney Cells: Therapeutic Implications for COVID-19 (Preprint)

10.2196/preprints.25089 ◽

2020 ◽

Author(s):

Avik Sotira Scientific

Keyword(s):

Social Life ◽

Plaque Assay ◽

Host Cells ◽

Surface Glycoprotein ◽

Crystallographic Structure ◽

Therapeutic Implications ◽

Biochemical Assays ◽

Targeted Medicine

UNSTRUCTURED Coronavirus disease 2019 (COVID-19) is a severe acute respiratory syndrome (SARS) caused by a virus known as SARS-Coronavirus 2 (SARS-CoV2). Without a targeted-medicine, this disease has been causing a massive humanitarian crisis not only in terms of mortality, but also imposing a lasting damage to social life and economic progress of humankind. Therefore, an immediate therapeutic strategy needs to be intervened to mitigate this global crisis. Here, we report a novel KepTide™ (Knock-End Peptide) therapy that nullifies SARS-CoV2 infection. SARS-CoV2 employs its surface glycoprotein “spike” (S-glycoprotein) to interact with angiotensin converting enzyme-2 (ACE-2) receptor for its infection in host cells. Based on our in-silico-based homology modeling study validated with a recent X-ray crystallographic structure (PDB ID:6M0J), we have identified that a conserved motif of S-glycoprotein that intimately engages multiple hydrogen-bond (H-bond) interactions with ACE-2 enzyme. Accordingly, we designed a peptide, termed as ACIS (ACE-2 Inhibitory motif of Spike), that displayed significant affinity towards ACE-2 enzyme as confirmed by biochemical assays such as BLItz and fluorescence polarization assays. Interestingly, more than one biochemical modifications were adopted in ACIS in order to enhance the inhibitory action of ACIS and hence called as KEpTide™. Consequently, a monolayer invasion assay, plaque assay and dual immunofluorescence analysis further revealed that KEpTide™ efficiently mitigated the infection of SARS-CoV2 in vitro in VERO E6 cells. Finally, evaluating the relative abundance of ACIS in lungs and the potential side-effects in vivo in mice, our current study discovers a novel KepTide™ therapy that is safe, stable, and robust to attenuate the infection of SARS-CoV2 virus if administered intranasally. INTERNATIONAL REGISTERED REPORT RR2-https://doi.org/10.1101/2020.10.13.337584

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Protective Effects of Lactoferrin against SARS-CoV-2 Infection In Vitro

Nutrients ◽

10.3390/nu13020328 ◽

2021 ◽

Vol 13 (2) ◽

pp. 328 ◽

Cited By ~ 1

Author(s):

Claudio Salaris ◽

Melania Scarpa ◽

Marina Elli ◽

Alice Bertolini ◽

Simone Guglielmetti ◽

...

Keyword(s):

Immune Response ◽

Epithelial Cells ◽

Intestinal Epithelial Cells ◽

Plaque Assay ◽

Immune Response Gene ◽

Intestinal Epithelial ◽

Antiviral Immune Response ◽

Qrt Pcr ◽

Anti Inflammatory

SARS-CoV-2 is a newly emerging virus that currently lacks curative treatments. Lactoferrin (LF) is a naturally occurring non-toxic glycoprotein with broad-spectrum antiviral, immunomodulatory and anti-inflammatory effects. In this study, we assessed the potential of LF in the prevention of SARS-CoV-2 infection in vitro. Antiviral immune response gene expression was analyzed by qRT-PCR in uninfected Caco-2 intestinal epithelial cells treated with LF. An infection assay for SARS-CoV-2 was performed in Caco-2 cells treated or not with LF. SARS-CoV-2 titer was determined by qRT-PCR, plaque assay and immunostaining. Inflammatory and anti-inflammatory cytokine production was determined by qRT-PCR. LF significantly induced the expression of IFNA1, IFNB1, TLR3, TLR7, IRF3, IRF7 and MAVS genes. Furthermore, LF partially inhibited SARS-CoV-2 infection and replication in Caco-2 intestinal epithelial cells. Our in vitro data support LF as an immune modulator of the antiviral immune response with moderate effects against SARS-CoV-2 infection.

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Honeysuckle Aqueous Extracts Induced let-7a Suppress EV71 Replication and Pathogenesis In Vitro and In Vivo and Is Predicted to Inhibit SARS-CoV-2

Viruses ◽

10.3390/v13020308 ◽

2021 ◽

Vol 13 (2) ◽

pp. 308

Author(s):

Ying-Ray Lee ◽

Chia-Ming Chang ◽

Yuan-Chieh Yeh ◽

Chi-Ying F. Huang ◽

Feng-Mao Lin ◽

...

Keyword(s):

Protein Expression ◽

Western Blotting ◽

Expression Profiles ◽

Plaque Assay ◽

Virus Titer ◽

Enterovirus 71 ◽

Luciferase Reporter ◽

Pathogen Invasion

Honeysuckle (Lonicera japonica Thunb) is a traditional Chinese medicine (TCM) with an antipathogenic activity. MicroRNAs (miRNAs) are small non-coding RNA molecules that are ubiquitously expressed in cells. Endogenous miRNA may function as an innate response to block pathogen invasion. The miRNA expression profiles of both mice and humans after the ingestion of honeysuckle were obtained. Fifteen overexpressed miRNAs overlapped and were predicted to be capable of targeting three viruses: dengue virus (DENV), enterovirus 71 (EV71) and SARS-CoV-2. Among them, let-7a was examined to be capable of targeting the EV71 RNA genome by reporter assay and Western blotting. Moreover, honeysuckle-induced let-7a suppression of EV71 RNA and protein expression as well as viral replication were investigated both in vitro and in vivo. We demonstrated that let-7a targeted EV71 at the predicted sequences using luciferase reporter plasmids as well as two infectious replicons (pMP4-y-5 and pTOPO-4643). The suppression of EV71 replication and viral load was demonstrated in two cell lines by luciferase activity, RT-PCR, real-time PCR, Western blotting and plaque assay. Furthermore, EV71-infected suckling mice fed honeysuckle extract or inoculated with let-7a showed decreased clinical scores and a prolonged survival time accompanied with decreased viral RNA, protein expression and virus titer. The ingestion of honeysuckle attenuates EV71 replication and related pathogenesis partially through the upregulation of let-7a expression both in vitro and in vivo. Our previous report and the current findings imply that both honeysuckle and upregulated let-7a can execute a suppressive function against the replication of DENV and EV71. Taken together, this evidence indicates that honeysuckle can induce the expression of let-7a and that this miRNA as well as 11 other miRNAs have great potential to prevent and suppress EV71 replication.

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Inhibition of p38 Mitogen-Activated Protein Kinase Impairs Mayaro Virus Replication in Human Dermal Fibroblasts and HeLa Cells

Viruses ◽

10.3390/v13061156 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1156

Author(s):

Madelaine Sugasti-Salazar ◽

Yessica Y. Llamas-González ◽

Dalkiria Campos ◽

José González-Santamaría

Keyword(s):

Protein Expression ◽

Hela Cells ◽

Plaque Assay ◽

Dermal Fibroblasts ◽

Dependent Manner ◽

Human Dermal Fibroblasts ◽

Mitogen Activated Protein ◽

Mayaro Virus ◽

The Impact ◽

Dose Dependent

Mayaro virus (MAYV) hijacks the host’s cell machinery to effectively replicate. The mitogen-activated protein kinases (MAPKs) p38, JNK, and ERK1/2 have emerged as crucial cellular factors implicated in different stages of the viral cycle. However, whether MAYV uses these MAPKs to competently replicate has not yet been determined. The aim of this study was to evaluate the impact of MAPK inhibition on MAYV replication using primary human dermal fibroblasts (HDFs) and HeLa cells. Viral yields in supernatants from MAYV-infected cells treated or untreated with inhibitors SB203580, SP600125, U0126, or Losmapimod were quantified using plaque assay. Additionally, viral protein expression was analyzed using immunoblot and immunofluorescence. Knockdown of p38⍺/p38β isoforms was performed in HDFs using the PROTACs molecule NR-7h. Our data demonstrated that HDFs are highly susceptible to MAYV infection. SB203580, a p38 inhibitor, reduced MAYV replication in a dose-dependent manner in both HDFs and HeLa cells. Additionally, SB203580 significantly decreased viral E1 protein expression. Similarly, knockdown or inhibition of p38⍺/p38β isoforms with NR-7h or Losmapimod, respectively, affected MAYV replication in a dose-dependent manner. Collectively, these findings suggest that p38 could play an important role in MAYV replication and could serve as a therapeutic target to control MAYV infection.

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Antiviral Activity of the PropylamylatinTM Formula against the Novel Coronavirus SARS-CoV-2 In Vitro Using Direct Injection and Gas Assays in Virus Suspensions

Viruses ◽

10.3390/v13030415 ◽

2021 ◽

Vol 13 (3) ◽

pp. 415

Author(s):

Ashley N. Brown ◽

Gary Strobel ◽

Kaley C. Hanrahan ◽

Joe Sears

Keyword(s):

Propionic Acid ◽

Infectious Virus ◽

Direct Injection ◽

Plaque Assay ◽

Antiviral Effect ◽

Dependent Manner ◽

Global Public Health ◽

Novel Coronavirus ◽

The Individual

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of novel coronavirus disease 2019 (COVID-19), has become a severe threat to global public health. There are currently no antiviral therapies approved for the treatment or prevention of mild to moderate COVID-19 as remdesivir is only approved for severe COVID-19 cases. Here, we evaluated the antiviral potential of a Propylamylatin formula, which is a mixture of propionic acid and isoamyl hexanoates. The Propylamylatin formula was investigated in gaseous and liquid phases against 1 mL viral suspensions containing 105 PFU of SARS-CoV-2. Viral suspensions were sampled at various times post-exposure and infectious virus was quantified by plaque assay on Vero E6 cells. Propylamylatin formula vapors were effective at inactivating infectious SARS-CoV-2 to undetectable levels at room temperature and body temperature, but the decline in virus was substantially faster at the higher temperature (15 min versus 24 h). The direct injection of liquid Propylamylatin formula into viral suspensions also completely inactivated SARS-CoV-2 and the rapidity of inactivation occurred in an exposure dependent manner. The overall volume that resulted in 90% viral inactivation over the course of the direct injection experiment (EC90) was 4.28 µls. Further investigation revealed that the majority of the antiviral effect was attributed to the propionic acid which yielded an overall EC90 value of 11.50 µls whereas the isoamyl hexanoates provided at most a 10-fold reduction in infectious virus. The combination of propionic acid and isoamyl hexanoates was much more potent than the individual components alone, suggesting synergy between these components. These findings illustrate the therapeutic promise of the Propylamylatin formula as a potential treatment strategy for COVID-19 and future studies are warranted.

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Cellular miR-101-1 Reduces Efficiently the Replication of HSV-1 in HeLa Cells

Intervirology ◽

10.1159/000512956 ◽

2021 ◽

Vol 64 (2) ◽

pp. 88-95

Author(s):

Bahar Sadegh Ehdaei ◽

Ahmad Pirouzmand ◽

Mehdi Shabani ◽

Arezoo Mirzaei ◽

Sharareh Moghim

Keyword(s):

Hela Cells ◽

Plaque Assay ◽

Viral Gene Expression ◽

Viral Gene ◽

Herpes Simplex Viruses ◽

Viral Progeny ◽

Immunosuppressed Patients ◽

Health Complications ◽

Hsv 1

Introduction: Herpes simplex viruses (HSVs) are widely distributed in the human population. HSV type 1 (HSV-1) is responsible for a spectrum of diseases, ranging from gingivostomatitis to keratoconjunctivitis, and encephalitis. The HSVs establish latent infections in nerve cells, and recurrences are common. Their frequent reactivation in elderly and immunosuppressed patients causes serious health complications. Objectives: Due to the growing resistance to its main drug, acyclovir, alternative treatments with different mechanisms of action are required. MicroRNAs regulate host and viral gene expression posttranscriptionally. Previous studies reported that mir-101-2 expression has widely participated in the regulation of HSV-1 replication. In this study, we investigate the effect of hsa-miR-101-1 in the replication of HSV-1. Methods: We found that transfection of miR-101-1 into HeLa cells could reduce effectively HSV-1 replication using plaque assay and real-time PCR methods. Results: We showed that overexpression of miR-10-1 produced less viral progeny and manifested a weaker cytopathic effect, without affecting cell viability. Discussion/Conclusion: This result can give us new insights into the control of HSV-1 infections.

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Combination Regimens of Favipiravir Plus Interferon Alpha Inhibit Chikungunya Virus Replication in Clinically Relevant Human Cell Lines

Microorganisms ◽

10.3390/microorganisms9020307 ◽

2021 ◽

Vol 9 (2) ◽

pp. 307

Author(s):

Evelyn J. Franco ◽

Xun Tao ◽

Kaley C. Hanrahan ◽

Jieqiang Zhou ◽

Jürgen B. Bulitta ◽

...

Keyword(s):

Combination Therapy ◽

Antiviral Activity ◽

Viral Replication ◽

Cell Lines ◽

Interferon Alpha ◽

Chikungunya Virus ◽

Plaque Assay ◽

Human Infection ◽

Viral Burden ◽

Combination Regimens

Chikungunya virus (CHIKV) is an alphavirus associated with a broad tissue tropism for which no antivirals or vaccines are approved. This study evaluated the antiviral potential of favipiravir (FAV), interferon-alpha (IFN), and ribavirin (RBV) against CHIKV as mono- and combination-therapy in cell lines that are clinically relevant to human infection. Cells derived from human connective tissue (HT-1080), neurons (SK-N-MC), and skin (HFF-1) were infected with CHIKV and treated with different concentrations of FAV, IFN, or RBV. Viral supernatant was sampled daily and the burden was quantified by plaque assay on Vero cells. FAV and IFN were the most effective against CHIKV on various cell lines, suppressing the viral burden at clinically achievable concentrations; although the degree of antiviral activity was heavily influenced by cell type. RBV was not effective and demonstrated substantial toxicity, indicating that it is not a feasible candidate for CHIKV. The combination of FAV and IFN was then assessed on all cell lines. Combination therapy enhanced antiviral activity in HT-1080 and SK-N-MC cells, but not in HFF-1 cells. We developed a pharmacokinetic/pharmacodynamic model that described the viral burden and inhibitory antiviral effect. Simulations from this model predicted clinically relevant concentrations of FAV plus IFN completely suppressed CHIKV replication in HT-1080 cells, and considerably slowed down the rate of viral replication in SK-N-MC cells. The model predicted substantial inhibition of viral replication by clinical IFN regimens in HFF-1 cells. Our results highlight the antiviral potential of FAV and IFN combination regimens against CHIKV in clinically relevant cell types.

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