scholarly journals Seleno-Functionalization of Quercetin Improves the Non-Covalent Inhibition of Mpro and Its Antiviral Activity in Cells against SARS-CoV-2

2021 ◽  
Vol 22 (13) ◽  
pp. 7048
Author(s):  
Francesca Mangiavacchi ◽  
Pawel Botwina ◽  
Elena Menichetti ◽  
Luana Bagnoli ◽  
Ornelio Rosati ◽  
...  
Keyword(s):  
Selenium Atom ◽  
Quercetin Derivatives ◽  
Main Protease ◽  
Infected Cells ◽  
Flavonoid Quercetin ◽  
Flavone Derivatives ◽  
Toxic Concentrations ◽  
First Time

The development of new antiviral drugs against SARS-CoV-2 is a valuable long-term strategy to protect the global population from the COVID-19 pandemic complementary to the vaccination. Considering this, the viral main protease (Mpro) is among the most promising molecular targets in light of its importance during the viral replication cycle. The natural flavonoid quercetin 1 has been recently reported to be a potent Mpro inhibitor in vitro, and we explored the effect produced by the introduction of organoselenium functionalities in this scaffold. In particular, we report here a new synthetic method to prepare previously inaccessible C-8 seleno-quercetin derivatives. By screening a small library of flavonols and flavone derivatives, we observed that some compounds inhibit the protease activity in vitro. For the first time, we demonstrate that quercetin (1) and 8-(p-tolylselenyl)quercetin (2d) block SARS-CoV-2 replication in infected cells at non-toxic concentrations, with an IC50 of 192 μM and 8 μM, respectively. Based on docking experiments driven by experimental evidence, we propose a non-covalent mechanism for Mpro inhibition in which a hydrogen bond between the selenium atom and Gln189 residue in the catalytic pocket could explain the higher Mpro activity of 2d and, as a result, its better antiviral profile.

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

scholarly journals Characterization of Postharvest Fungicide-Resistant Botrytis cinerea Isolates From Commercially Stored Apple Fruit

2017 ◽  
Vol 107 (3) ◽  
pp. 362-368 ◽  
Author(s):  
Wayne M. Jurick ◽  
Otilia Macarisin ◽  
Verneta L. Gaskins ◽  
Eunhee Park ◽  
Jiujiang Yu ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Gray Mold ◽  
Apple Fruit ◽  
Sublethal Dose ◽  
Long Term Storage ◽  
Pose Control ◽  
First Time

Botrytis cinerea causes gray mold and is an economically important postharvest pathogen of fruit, vegetables, and ornamentals. Fludioxonil-sensitive B. cinerea isolates were collected in 2011 and 2013 from commercial storage in Pennsylvania. Eight isolates had values for effective concentrations for inhibiting 50% of mycelial growth of 0.0004 to 0.0038 μg/ml for fludioxonil and were dual resistant to pyrimethanil and thiabendazole. Resistance was generated in vitro, following exposure to a sublethal dose of fludioxonil, in seven of eight dual-resistant B. cinerea isolates. Three vigorously growing B. cinerea isolates with multiresistance to postharvest fungicides were further characterized and found to be osmosensitive and retained resistance in the absence of selection pressure. A representative multiresistant B. cinerea strain caused decay on apple fruit treated with postharvest fungicides, which confirmed the in vitro results. The R632I mutation in the Mrr1 gene, associated with fludioxonil resistance in B. cinerea, was not detected in multipostharvest fungicide-resistant B. cinerea isolates, suggesting that the fungus may be using additional mechanisms to mediate resistance. Results from this study show for the first time that B. cinerea with dual resistance to pyrimethanil and thiabendazole can also rapidly develop resistance to fludioxonil, which may pose control challenges in the packinghouse environment and during long-term storage.

scholarly journals In vivo analysis of influenza A mRNA secondary structures identifies critical regulatory motifs

2019 ◽  
Vol 47 (13) ◽  
pp. 7003-7017 ◽  
Author(s):  
Lisa Marie Simon ◽  
Edoardo Morandi ◽  
Anna Luganini ◽  
Giorgio Gribaudo ◽  
Luis Martinez-Sobrido ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Influenza A ◽  
Host Cells ◽  
Messenger Rnas ◽  
Infected Cells ◽  
In Vivo Analysis ◽  
First Time ◽  
Negative Sense

AbstractThe influenza A virus (IAV) is a continuous health threat to humans as well as animals due to its recurring epidemics and pandemics. The IAV genome is segmented and the eight negative-sense viral RNAs (vRNAs) are transcribed into positive sense complementary RNAs (cRNAs) and viral messenger RNAs (mRNAs) inside infected host cells. A role for the secondary structure of IAV mRNAs has been hypothesized and debated for many years, but knowledge on the structure mRNAs adopt in vivo is currently missing. Here we solve, for the first time, the in vivo secondary structure of IAV mRNAs in living infected cells. We demonstrate that, compared to the in vitro refolded structure, in vivo IAV mRNAs are less structured but exhibit specific locally stable elements. Moreover, we show that the targeted disruption of these high-confidence structured domains results in an extraordinary attenuation of IAV replicative capacity. Collectively, our data provide the first comprehensive map of the in vivo structural landscape of IAV mRNAs, hence providing the means for the development of new RNA-targeted antivirals.

scholarly journals Chemerin-ChemR23 Signaling in Tooth Development

2012 ◽  
Vol 91 (12) ◽  
pp. 1147-1153 ◽  
Author(s):  
T. Ohira ◽  
D. Spear ◽  
N. Azimi ◽  
V. Andreeva ◽  
P.C. Yelick
Keyword(s):  
Progenitor Cells ◽  
Molecular Mechanisms ◽  
Tooth Development ◽  
Expression Patterns ◽  
Cell Interactions ◽  
Specific Expression ◽  
Ribosomal Protein S6 ◽  
First Time

Our long-term goal is to identify and characterize molecular mechanisms regulating tooth development, including those mediating the critical dental epithelial-dental mesenchymal (DE-DM) cell interactions required for normal tooth development. The goal of this study was to investigate Chemerin (Rarres2)/ChemR23(Cmklr1) signaling in DE-DM cell interactions in normal tooth development. Here we present, for the first time, tissue-specific expression patterns of Chemerin and ChemR23 in mouse tooth development. We show that Chemerin is expressed in cultured DE progenitor cells, while ChemR23 is expressed in cultured DM cells. Moreover, we demonstrate that ribosomal protein S6 (rS6) and Akt, downstream targets of Chemerin/ChemR23 signaling, are phosphorylated in response to Chemerin/ChemR23 signaling in vitro and are expressed in mouse tooth development. Together, these results suggest roles for Chemerin/ChemR23-mediated DE-DM cell signaling during tooth morphogenesis.

scholarly journals Latent Antigen Vaccination in a Model Gammaherpesvirus Infection

2001 ◽  
Vol 75 (17) ◽  
pp. 8283-8288 ◽  
Author(s):  
Edward J. Usherwood ◽  
Kimberley A. Ward ◽  
Marcia A. Blackman ◽  
James P. Stewart ◽  
David L. Woodland
Keyword(s):  
Latent Infection ◽  
Model Systems ◽  
Murine Gammaherpesvirus ◽  
Latently Infected ◽  
Associated Proteins ◽  
Infected Cells ◽  
The Impact ◽  
First Time

ABSTRACT Vaccines that can reduce the load of latent gammaherpesvirus infections are eagerly sought. One attractive strategy is vaccination against latency-associated proteins, which may increase the efficiency with which T cells recognize and eliminate latently infected cells. However, due to the lack of tractable animal model systems, the effect of latent-antigen vaccination on gammaherpesvirus latency is not known. Here we use the murine gammaherpesvirus model to investigate the impact of vaccination with the latency-associated M2 antigen. As expected, vaccination had no effect on the acute lung infection. However, there was a significant reduction in the load of latently infected cells in the initial stages of the latent infection, when M2 is expressed. These data show for the first time that latent-antigen vaccination can reduce the level of latency in vivo and suggest that vaccination strategies involving other latent antigens may ultimately be successfully used to reduce the long-term latent infection.

scholarly journals Ivermectin the Promising Drug to Stave off the COVID-19 Crisis: A Review

2021 ◽  
Vol 7 (2) ◽  
pp. 95-98
Author(s):  
Zakia Jahan ◽  
Masudul Hassan
Keyword(s):  
Infectious Diseases ◽  
Specific Treatment ◽  
In Vitro Study ◽  
Antiviral Effect ◽  
Viral Particles ◽  
The World ◽  
Infected Cells ◽  
Almost All ◽  
First Time

The Coronavirus disease 2019 (COVID-19) outbreak, forcing us to face unprecedented moments in the world. The huge devastating impact of the world due to the covid-19 attack causes the brink of no return. However, there is no proven and specific treatment for Covid -19. Very few medications have received Emergency Use of Authorization. A recent in vitro study was the first time to find out and to assess the antiviral effect of Ivermectin on COVID-19. The study showed that Ivermectin was active against COVID- 19-infected cells, was able to kill effectively almost all viral particles within 48 h. In these moments of crisis, FDA-approved ivermectin is a ray of hope. Bangladesh Journal of Infectious Diseases 2020;7(2):95-98

scholarly journals Organoselenium mild electrophiles in the inhibition of Mpro and SARSCoV-2 replication

2020 ◽  
Author(s):  
Luca Sancineto ◽  
Francesca Mangiavacchi ◽  
Agnieszka Dąbrowska ◽  
Agata Pacuła ◽  
Magdalena Obieziurska-Fabisiak ◽  
...  
Keyword(s):  
Cytopathic Effect ◽  
Selenium Atom ◽  
Inhibition Activity ◽  
Exchange Processes ◽  
Main Protease ◽  
In Vitro Inhibition ◽  
Complex Scenario ◽  
Detoxification Process

New Ebselen-like derivatives resulted to be very strong in vitro inhibitors of SARS-CoV-2 main protease. We demonstrated that this activity mainly depends on the electrophilicity of the selenium atom that is considerably higher in the N-substituted 1,2- benzoselenazol-3(2H)-ones respect to the corresponding diselenides allowing it to be rapidly attached by free thiols affording sulfur-selenium intermediates that are further subjected to thiol exchange processes. This data paints a very complex scenario that requires us to consider Ebselen and Ebselen-like derivatives as potential electrophilic substrates for the several other free thiols present in the cell beside the target free cysteine. The sulfur selenium intermediates are milder electrophiles that could be theoretically implicated in both the detoxification process as well as in the final enzymatic inhibition. We here demonstrated that the in vitro inhibition activity is not fully reproduced in the prevention of viral replication in the cell-based assay. This indicates that the structure of the substituents introduced in the Ebselen scaffold is a crucial factor to control the reactivity of the selenated molecule in the network of thiol exchanges, as well as for molecular recognition of the targeted enzymatic cysteine. For this reason, an in-depth investigation is strongly desirable to better understand how to increase the activity and the selectivity of Ebselen derivatives overcoming the issues of the apparent PAINS-like role of Ebselen. Furthermore, besides the antiviral activity, thee selected compounds also showed a different ability to reduce the virus-induced cytopathic effect, indicating that other mechanisms could be implicated. One may consider here the well-known cytoprotective antioxidant activity of Ebselen and its derivatives.<p></p>

scholarly journals Bepridil is potent against SARS-CoV-2 In Vitro

2020 ◽  
Author(s):  
Erol C. Vatansever ◽  
Kai Yang ◽  
Kaci C. Kratch ◽  
Aleksandra Drelich ◽  
Chia-Chuan Cho ◽  
...  
Keyword(s):  
Small Molecule ◽  
A549 Cells ◽  
Live Virus ◽  
Docking Analysis ◽  
Computational Docking ◽  
Main Protease ◽  
Infected Cells ◽  
Endosomal Ph ◽  
Cytopathogenic Effect

ABSTRACTGuided by a computational docking analysis, about 30 FDA/EMA-approved small molecule medicines were characterized on their inhibition of the SARS-CoV-2 main protease (MPro). Of these tested small molecule medicines, six displayed an IC50 value in inhibiting MPro below 100 μM. Three medicines pimozide, ebastine, and bepridil are basic small molecules. Their uses in COVID-19 patients potentiate dual functions by both raising endosomal pH to slow SARS-CoV-2 entry into the human cell host and inhibiting MPro in infected cells. A live virus-based microneutralization assay showed that bepridil inhibited cytopathogenic effect induced by SARS-CoV-2 in Vero E6 cells completely at and dose-dependently below 5 μM and in A549 cells completely at and dose-dependently below 6.25 μM. Therefore, the current study urges serious considerations of using bepridil in COVID-19 clinical tests.

scholarly journals Infectious Norovirus Is Chronically Shed by Immunocompromised Pediatric Hosts

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 619
Author(s):  
Amy Davis ◽  
Valerie Cortez ◽  
Marco Grodzki ◽  
Ronald Dallas ◽  
Jose Ferrolino ◽  
...  
Keyword(s):  
Infectious Virus ◽  
Chronic Infections ◽  
Vitro Assay ◽  
Virus Shedding ◽  
Temporal Aspects ◽  
Male Patients ◽  
Immunocompromised Hosts ◽  
First Time

Noroviruses are a leading cause of gastroenteritis worldwide. Although infections in healthy individuals are self-resolving, immunocompromised individuals are at risk for chronic disease and severe complications. Chronic norovirus infections in immunocompromised hosts are often characterized by long-term virus shedding, but it is unclear whether this shed virus remains infectious. We investigated the prevalence, genetic heterogeneity, and temporal aspects of norovirus infections in 1140 patients treated during a 6-year period at a pediatric research hospital. Additionally, we identified 20 patients with chronic infections lasting 37 to >418 days. Using a new human norovirus in vitro assay, we confirmed the continuous shedding of infectious virus for the first time. Shedding lasted longer in male patients and those with diarrheal symptoms. Prolonged shedding of infectious norovirus in immunocompromised hosts can potentially increase the likelihood of transmission, highlighting the importance of isolation precautions to prevent nosocomial infections.

scholarly journals Alternative mechanisms with and without steel factor support primitive human hematopoiesis

Blood ◽  
1993 ◽  
Vol 81 (6) ◽  
pp. 1465-1470 ◽  
Author(s):  
HJ Sutherland ◽  
DE Hogge ◽  
D Cook ◽  
CJ Eaves
Keyword(s):  
Hematopoietic Stem ◽  
Steel Factor ◽  
Stem Cell Maintenance ◽  
Murine Fibroblasts ◽  
Normal Human ◽  
Clonogenic Cell ◽  
First Time ◽  
Stimulating Factor

Abstract As a first approach to defining the molecular requirements for supporting human hematopoietic stem cell maintenance and differentiation in vitro, we have analyzed and compared the ability of various factors to support the maintenance and initial differentiation of human long-term culture-initiating cells (LTC-ICs), a distinct, rare primitive hematopoietic cell type whose progeny after 5 weeks include cells detectable as colony-forming cells. Normal human marrow cells highly enriched in LTC-ICs (approximately 1% pure) were placed in cultures containing either preestablished, irradiated human marrow adherent feeder layers, or feeders consisting of Steel factor-deficient SI/SI, or normal +/+ murine fibroblasts, or no feeders. In some groups, either Steel factor alone, granulocyte colony-stimulating factor (G- CSF) and interleukin-3 (IL-3), or all three factors combined were also added repeatedly. SI/SI murine fibroblasts were equivalent to +/+ controls and to normal human marrow feeders in supporting both LTC-IC maintenance and clonogenic cell output over a 5-week period. Soluble Steel factor alone could, however, effectively substitute for human marrow feeders to support LTC-IC maintenance, although clonogenic cell output was markedly reduced under these conditions. Conversely, soluble Steel factor with G-CSF and IL-3 or with feeders (or all together) did not further enhance (or depress) LTC-IC maintenance, although under these conditions clonogenic cell output was markedly increased. These findings confirm previous evidence that LTC-IC maintenance and clonogenic cell production are differentially regulated and show for the first time that LTC-IC maintenance can be supported by different nonsynergizing factors that may, but need not, include Steel factor.

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