The RNA-dependent RNA polymerase (RdRp) and 3C-like protease (3CLpro) from SARS-CoV-2 play crucial roles in the viral life cycle and are considered the most promising targets for drug discovery against SARS-CoV-2. In this study, FDA-approved drugs were screened to identify the probable anti-RdRp and 3CLpro inhibitors by molecular docking approach. The number of ligands selected from the PubChem database of NCBI for screening was 1760. Ligands were energy minimized using Open Babel. The RdRp and 3CLpro protein sequences were retrieved from the NCBI database. For Homology Modeling predictions, we used the Swiss model server. Their structure was then energetically minimized using SPDB viewer software and visualized in the CHIMERA UCSF software. Molecular dockings were performed using AutoDock Vina, and candidate drugs were selected based on binding affinity (∆G). Hydrogen bonding and hydrophobic interactions between ligands and proteins were visualized using Ligplot and the Discovery Studio Visualizer v3.0 software. Our results showed 58 drugs against RdRp, which had binding energy of − 8.5 or less, and 69 drugs to inhibit the 3CLpro enzyme with a binding energy of − 8.1 or less. Six drugs based on binding energy and number of hydrogen bonds were chosen for the next step of molecular dynamics (MD) simulations to investigate drug-protein interactions (including Nilotinib, Imatinib and dihydroergotamine for 3clpro and Lapatinib, Dexasone and Relategravir for RdRp). Except for Lapatinib, other drugs-complexes were stable during MD simulation. Raltegravir, an anti-HIV drug, was observed to be the best compound against RdRp based on docking binding energy (− 9.5 kcal/mole) and MD results. According to the MD results and binding energy, dihydroergotamine is a suitable candidate for 3clpro inhibition (− 9.6 kcal/mol). These drugs were classified into several categories, including antiviral, antibacterial, anti-inflammatory, anti-allergic, cardiovascular, anticoagulant, BPH and impotence, antipsychotic, antimigraine, anticancer, and so on. The common prescription-indications for some of these medication categories appeared somewhat in line with manifestations of COVID-19. We hope that they can be beneficial for patients with certain specific symptoms of SARS-CoV-2 infection, but they can also probably inhibit viral enzymes. We recommend further experimental evaluations in vitro and in vivo on these FDA-approved drugs to assess their potential antiviral effect on SARS-CoV-2.

Nosocomial infections caused by Acinetobacter baumannii (A. baumannii) are considered as a global serious problem in hospitalized patients because of emerging antibiotic resistance. Immunotherapy approaches are promising to prevent such infections. In our previous study, five antigenic epitopes of outer membrane protein A (OmpA), as the most dangerous virulence molecule in A. baumanii, were predicted in silico. In this study, the investigators evaluated some immunological aspects of the peptides.Five peptides were separately injected into C5BL/6 mice; then the cytokine production (interleukin-4 and interferon-gamma) of splenocytes and opsonophagocytic activity of immunized serum were assessed. To identify the protective function of the peptides, animal models of sepsis and pneumonia infections were actively and passively immunized with selected peptides and pooled sera of immunized mice, respectively. Then, their survival rates were compared with the non-infected controls.Based on the results, activated spleen cells in P127 peptide-immunized mice exhibited an increased level of IFN-γ compared with the other experimental groups, but not about the IL-4 concentration. The results of the opsonophagocytic assay revealed an appropriate killing the activity of produced antibodies against A. baumannii in a dose-dependent manner. Further, the survival rates of the mice under passive immunization with the immunized sera or active immunization with P127 peptide were significantly more than those in the control group. Moreover, the survival rate of the P127 peptide immunized group was considerably higher than that of the other peptide-immunized group.In conclusion, findings indicated that peptides derived from OmpA can be used as a promising tool for designing the epitope-based vaccines against infections caused by A. baumannii.

The most preferred method for the detection of foot-and-mouth disease (FMD) viral antigen and identification of viral serotype is the ELISA. Diagnostic tests with high sensitivity is necessary both to distinguish infected vaccinated animals and disease control programs for identifying the carrier animals. To detection of FMD virus, the current strategies are mainly based on capture antibody (sandwich) ELISA test. Applying laying pullets as animal bioreactor for production specific egg yolk antibody (IgY) has increased in recent years due to its high yield, affinity, low price, and quick production turnover. In the present study, we aimed to produce a concentrated and purifies IgY polyclonal antibody to design a capture antibody ELISA kit against the FMD virus (FMDV) serotype A. At first, laying hens were immunized by inactivated FMDV serotype virus and then, on days 14, 21, and 28 following vaccination, the eggs and sera were collected and then, the IgY polyclonal antibodies were extracted and purified from the chicken egg yolk using polyethylene glycol 6000–ethanol precipitation procedure. Extracts were filtered, purified by ion exchange chromatography and dialyzed. The purified IgY concentration estimated by Bradford assay, confirmed it presents by SDS-PAGE and Western blot and also its specific immune reaction by Ouchterlony double immunodiffusion and Dot blot tests. Moreover, for achieving optimum concentration of antigen/antibody (sera) in sandwich ELISA, checkerboard titration test was setup base on indirect ELISA results. Eventually, 119 previously confirmed samples (including 80 positive and 39 negative) by both Real time PCR (quantitative PCR, qPCR) and with a commercial ELISA kit, used for evaluation of sensitivity and accuracy of our developed Capture antibody ELISA kit. In this manner, the sensitivity and specificity of our designed kit was 100% and 98%, respectively. According to this, the present developed capture ELISA kit based on IgY has high sensitivity and specificity for FMD virus detection and it could be used in future as both commercial detecting and serotyping applications.

Background: Bovine coronaviruses (BCoVs) are zoonotic diseases that result in substantial economic losses due to mortality, impaired growth, and increased medication expenses in large animals. These viruses pose a risk to children who live beside infected animal, as they can cause diarrhea. This study was dedicated to molecular and antigen detections and phylogenetic and immunoinformatics analysis of zoonotic coronavirus (CoV) in Iran. Materials and Methods: A total of 77 diarrheic samples were collected from Holstein dairy herds in selected provinces of Iran. Samples were tested by capture antibody enzyme-linked immunosorbent assay (ELISA) to detect CoV and reverse transcriptase–polymerase chain reaction (RT–PCR) for verification of detection and also genotyping of spike glycoprotein in CoV-positive samples. After statistical analysis, nucleotide sequence alignment, and nucleotide and protein phylogenetic tree construction, the centralized sequence for vaccine strains was obtained using computationally optimized broadly reactive antigen (COBRA)'s center-of-the-tree (COT) method. Results: Twenty-two (28.5%) and eight (10.3%) of 77 samples were positive according to RT–PCR and ELISA, respectively. (Basic Local Alignment Search Tool) BLAST and phylogenetic analysis revealed that most similar sequences to the Iranian CoV sequence were for European countries. Furthermore, there were strong correlations to other CoVs in humans and wild and domesticated animals. As CoV has variable COT, the most recent strains and COBRA vaccine strains were obtained. Conclusion: Based on the high prevalence of this viral disease in calves and its economic impact on the breeding industry, as well as the potential transmission to humans and correlation with World Health Organization (WHO) One Health approach guidelines, the study emphasizes the importance of implementing preventive strategies such as animal vaccination.