Antiviral activity of 5-aminolevulinic acid against variants of severe acute respiratory syndrome coronavirus 2

Background Genetic variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began to emerge in 2020 and have been spreading globally during the coronavirus disease 2019 (COVID-19) pandemic. Despite the presence of different COVID-19 vaccines, the discovery of effective antiviral therapeutics for the treatment of patients infected with SARS-CoV-2 are still urgently needed. A natural amino acid, 5-aminolevulinic acid (5-ALA), has exhibited both antiviral and anti-inflammatory activities. In a previous study, we demonstrated an in vitro antiviral effect of 5-ALA against SARS-CoV-2 infection without significant cytotoxicity. In the present study, we sought to investigate whether 5-ALA with or without sodium ferrous citrate (SFC) can inhibit in vitro both the original SARS-CoV-2 Wuhan strain and its variants, including the Alpha, Beta, Gamma and Delta strains. Methods The antiviral activity of ALA with or without SFC was determined in Vero-E6 cell. The virus inhibition was quantified by real time RT-PCR. Results Co-administration of 5-ALA and SFC inhibited the Wuhan, Alpha and Delta variants of SARS-CoV-2 with IC50 values of 235, 173 and 397 µM, respectively, and the Beta and Gamma variants with IC50 values of 1311 and 1516 µM. Conclusion Our study suggests that 5-ALA with SFC warrants accelerated clinical evaluation as an antiviral drug candidate for treating patients infected with SARS-CoV-2 variants.

Diverse Regulations of Viral and Host Genes in Tomato Germplasms Responding to Tomato Yellow Leaf Curl Virus Inoculation

Tomato yellow leaf curl virus (TYLCV) is the dominating pathogen of tomato yellow leaf curl disease that caused severe loss to tomato production in China. In this study, we found that a TYLCV-resistant tomato line drastically reduced the accumulation of viral complementary-sense strand mRNAs but just moderately inhibit that of viral DNA and virion-sense strand mRNAs. However, two other resistant lines did not have such virus inhibition pattern. Analysis of differential expressed genes showed that the potential host defense-relevant processes varied in different resistant tomatoes, as compared to the susceptible line, suggesting a diversity of tomato TYLCV-resistance mechanisms.

Human Defensins from antivirals to vaccine adjuvants: rediscovery of the innate immunity arsenal

: Human defensins are a class of antimicrobial peptides, belonging to the innate immunity system. These peptides are expressed at the level of respiratory tract (both upper and lower) where they represent the first line of defense against pathogens; they are also known for their activity against different viruses, acting through diverse mechanisms, including direct binding to the virus, inhibition of viral replication, and aggregation of virions. It has been recently reported they are also effective against SARS-CoV-2. Moreover, they influence the immune response stimulating it in the challenge against microorganisms. An intriguingly potential application of defensin is related to their use as vaccine adjuvants; indeed, some in silico studies suggested their efficacy in boosting the immune response. Since the long-term persistence of acquired immunity against SARS-CoV-2 triggered by the currently employed vaccines is not known, natural agents with enhancing effects, such as defensins, administered with the vaccine, can be an interesting and attractive alternative.

In Silico Study of The Potential of Naturally Caffeoylquinic Acids From Lentinus Crinitus Basidiocarp With Zika Virus Inhibition Targets

The methanolic extract of the fungus Lentinus crinitus was submitted to biological assays, identification of the chemical composition by LC-MS, and in silico study by molecular docking with all identified compounds. The test against Artemis salina reached LD50 > 1000 μg/mL within 24h, and total mortality within 48 hours; the antioxidant test 62.4% inhibition in 1.0 mg/mL was obtained. Only 16 compounds were identified from the LC-MS analysis based on the comparison of reports already recorded in the literature. Most of the compounds identified here are described for the first time in the genus Lentinus. These results showed that the fungus is a producer of different classes of secondary metabolites biologically active. The results of the molecular docking simulation of the identified phytochemicals presented 1,13,4-di-O-Caffeoylquinic, as the leading promising candidate in the inhibition of the Zika virus.

Characterization and Structural Prediction of ORF10, ORF7b, ORF7a, ORF6, Membrane Glycoprotein, and Envelope Protein in SARS-CoV-2 Bangladeshi Variant through Bioinformatics Approach

The acute respiratory disease induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global epidemic in just less than a year by the first half of 2020. The subsequent efficient human-to-human transmission of this virus eventually affected millions of people worldwide. The most devastating thing is that the infection rate is continuously uprising and resulting in significant mortality especially among the older age population and those with health comorbidities.This enveloped, positive-sense RNA virus is chiefly responsible for the infection of the upper respiratory system. The virulence of the SARS-CoV-2 is mostly regulated by its proteins like entry to the host cell through fusion mechanism, fusion of infected cells with neighboring uninfected cells to spread the virus, inhibition of host gene expression, cellular differentiation, apoptosis, mitochondrial biogenesis, etc. But very little is known about the protein structures and functionalities. Therefore, the main purpose of this study is to learn more about these proteins through bioinformatics approaches. In this study, ORF10, ORF7b, ORF7a, ORF6, membrane glycoprotein, and envelope protein have been selected from a Bangladeshi Coronavirus strain G039392 and a number of bioinformatics tools MEGA-X-V10.1.7 PONDR, ProtScale, ProtParam, SCRIBER NetSurfP v2.0, IntFOLD UCSF Chimera and PyMol) and strategies were implemented for multiple sequence alignment and phylogeny analysis with 9 different variants, predicting hydropathicity, amino acid compositions, protein binding propensity, protein disorders, 2D and 3D protein modeling. Selected proteins were characterized as highly flexible, structurally and electrostatically extremely stable, ordered, biologically active, hydrophobic, and closely related to the proteins of different variants. This detailed information regarding the characterization and structure of proteins of SARS-CoV-2 Bangladeshi variant was performed for the first time ever to unveil the deep mechanism behind the virulence features and also, this robust appraisal paves the future way for molecular docking, vaccine development targeting these characterized proteins.

Wolbachia strain wAu differs in cellular perturbation and virus inhibition profiles from previously characterised Wolbachia strains

Some strains of the inherited bacterium Wolbachia have been shown to be effective at reducing the transmission of dengue and other positive-sense RNA viruses by Aedes aegypti in both laboratory and field settings and are being deployed for dengue control. The degree of virus inhibition varies between Wolbachia strains density and tissue tropism can contribute to these differences but there are also indications that this is not the only factor involved: for example, strains wAu and wAlbA are maintained at similar densities but only wAu produces strong dengue inhibition. We previously reported perturbations in lipid transport dynamics, including sequestration of cholesterol in lipid droplets, with strains wMel/wMelPop in Ae.aegypti. Here we show that strain wAu does not produce the same cholesterol sequestration phenotype despite displaying strong virus inhibition and moreover, in contrast to wMel, wAu antiviral activity was not rescued by cyclodextrin treatment. To further investigate the cellular basis underlying these differences, proteomic analysis of midguts was carried out on Ae. aegypti lines and revealed that wAu-carrying midguts showed a distinct proteome when compared to Wolbachia-free, wMel- or wAlbA-carrying midguts, in particular with respect to lipid transport and metabolism. The data suggest a possible role for perturbed RNA processing pathways in wAu virus inhibition. Together these results indicate that wAu shows unique features in its inhibition of arboviruses compared to previously characterized Wolbachia strains.

IFITM proteins promote SARS-CoV-2 infection and are targets for virus inhibition in vitro

Interferon-induced transmembrane proteins (IFITMs 1, 2 and 3) can restrict viral pathogens, but pro- and anti-viral activities have been reported for coronaviruses. Here, we show that artificial overexpression of IFITMs blocks SARS-CoV-2 infection. However, endogenous IFITM expression supports efficient infection of SARS-CoV-2 in human lung cells. Our results indicate that the SARS-CoV-2 Spike protein interacts with IFITMs and hijacks them for efficient viral infection. IFITM proteins were expressed and further induced by interferons in human lung, gut, heart and brain cells. IFITM-derived peptides and targeting antibodies inhibit SARS-CoV-2 entry and replication in human lung cells, cardiomyocytes and gut organoids. Our results show that IFITM proteins are cofactors for efficient SARS-CoV-2 infection of human cell types representing in vivo targets for viral transmission, dissemination and pathogenesis and are potential targets for therapeutic approaches.

Identification of bacteria in the tracheal swabs of farmed ostriches and their effect on the viability of influenza A virus

Avian influenza surveillance is a requirement for commercial trade in ostrich products, but influenza A viruses (IAVs) have proven difficult to isolate from ostrich tracheal swabs that test positive using molecular methods. We hypothesized that microbes unique to the ostrich trachea propagate in the transport medium after sampling and affect viral viability. We cultured tracheal swabs from 50 ostriches on 4 farms in South Africa, and recovered and identified 13 bacterial, 1 yeast, and 2 fungal species. Dietzia sp. had not been identified previously in the oropharyngeal tract of a bird, to our knowledge. The bacteria were tested for antimicrobial susceptibility, and most aerobic species, except for Streptococcus sp. and Pseudomonas sp., were sensitive to enrofloxacin; all were susceptible to sulfonamide. Virus inhibition experiments determined that ostrich-source Streptococcus sp., Pantoea sp., and Citrobacter freundii produced extracellular metabolites that caused a substantial reduction in the IAV titers of 99.9%. Streptomyces, Corynebacterium, Staphylococcus, Arthrobacter gandavensis, Pseudomonas putida, and Acinetobacter spp. similarly reduced the viability of IAV from 77.6% to 24.1%. Dietzia appeared to have no effect, but Rothia dentocariosa, Rhodotorula spp., and Clostridium spp. slightly increased the viability of IAV by 25.9, 34.9, and 58.5%, respectively.

Reliable Estimation of CD8 T Cell Inhibition of In Vitro HIV-1 Replication

The HIV-1 viral inhibition assay (VIA) measures CD8 T cell-mediated inhibition of HIV replication in CD4 T cells and is increasingly used for clinical testing of HIV vaccines and immunotherapies. The VIA has multiple sources of variability arising from in vitro HIV infection and co-culture of two T cell populations. Here, we describe multiple modifications to a 7-day VIA protocol, the most impactful being the introduction of independent replicate cultures for both HIV infected-CD4 (HIV-CD4) and HIV-CD4:CD8 T cell cultures. Virus inhibition was quantified using a ratio of weighted averages of p24+ cells in replicate cultures and the corresponding 95% confidence interval. An Excel template is provided to facilitate calculations. Virus inhibition was higher in people living with HIV suppressed on antiretroviral therapy (n=14, mean: 40.0%, median: 43.8%, range: 8.2 to 73.3%; p < 0.0001, two-tailed, exact Mann-Whitney test) compared to HIV-seronegative donors (n = 21, mean: -13.7%, median: -14.4%, range: -49.9 to 20.9%) and was stable over time (n = 6, mean %COV 9.4%, range 0.9 to 17.3%). Cross-sectional data were used to define 8% inhibition as the threshold to confidently detect specific CD8 T cell activity and determine the minimum number of culture replicates and p24+ cells needed to have 90% statistical power to detect this threshold. Last, we note that, in HIV seronegative donors, the addition of CD8 T cells to HIV infected CD4 T cells consistently increased HIV replication, though the level of increase varied markedly between donors. This co-culture effect may contribute to the weak correlations observed between CD8 T cell VIA and other measures of HIV-specific CD8 T cell function.