The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) was isolated in 2012 and is well known to cause the respiratory syndrome. The orf1ab gene is known to mediate MERS-CoV replication. In this study, we have discussed the in silico prediction of potential siRNAs targeting MERS-CoV-orf1ab gene for antiviral therapeutics. To identify the potential siRNAs, various factors were considered. We have excluded the siRNAs with off-target effects and potential binding with human mRNAs. By using available softwares, total twenty-one functional, off-target reduced potential siRNA were selected from four hundred and sixty-two siRNAs based on greater potency and specificity. We have tested only seven siRNAs initially to evaluate their performance by reverse transfection approach by lipofectamine mediated delivery in Vero cells. The evaluation results showed no cytotoxicity at various concentrations of siRNAs used. The results obtained in this study provided preliminary information about the cytotoxicity which will help us to further evaluate siRNAs in other cell cultures to find out the replication inhibition efficiency of MERS-CoV. Finally, it is concluded that the in silico prediction and designing resulted in filtration and selection of potential siRNAs with high accuracy, efficiency, and strength which can be further utilized for the development of oligonucleotide-based therapeutics.

Background: Some viruses cause outbreaks which require immediate attention. Neutralizing antibodies could be developed for viral outbreak management. However, development of monoclonal antibodies is often long, laborious, and unprofitable. Here we report a Norwegian platform for development of chicken polyclonal neutralizing antibodies with powerful therapeutic potential. Methods: Layers were immunized twice with 14-day interval using purified RBD of SARS-CoV-2. Eggs were harvested 14 days after the second immunization. Polyclonal IgY antibodies were extracted. Binding of anti-RBD IgY to RBD was measured by indirect ELISA. Neutralization capacity of anti-RBD IgYs was measured in Vero-E6 cells infected with SARS-CoV-2-mCherry strain using fluorescence and cell viability assay. In addition, the effect of IgYs on the expression of SARS-CoV-2 and host cytokine genes in lungs of Syrian Golden hamsters was examined using qRT-PCR. Results: Anti-RBD IgYs efficiently bind RBD of S protein of SARS-CoV-2 in situ, neutralize the virus in vitro, and lower viral RNA amplification without significant alteration of virus-mediated immune gene expression in vivo. Conclusions: Altogether, our results indicated that chicken polyclonal IgYs can be attractive targets for pre-clinical and clinical development for rapid management of outbreaks of emerging and re-emerging viruses.

A series of novel asymmetrical mono-carbonyl analogs of curcumin (AMACs) were synthesized and evaluated for cytotoxic activity using the brine shrimp lethality test (BSLT) and the methyl thiazolyl tetrazolium assay against Vero, HeLa, and MCF7 cell lines. The structures of the synthesized compounds were confirmed by Fourier transform infrared spectrophotometry (FTIR), ¹H-nuclear magnetic resonance (NMR), ¹³C-NMR, and mass spectral data. The results of the cytotoxicity evaluation showed that the synthesized compounds exhibited moderate to very high toxic activity in BSLT, requiring a concentration of 13.06–714.49 µg/mL to kill half the population. Most of the compound exhibited cytotoxic activity against HeLa cell lines, comparable to the activity of cisplatin with a concentration of the synthesized compounds required to inhibit 50% of the growth of the cell lines (IC₅₀) value of 40.65–95.55 µM, and most of the compounds tested against MCF7 cell lines exhibited moderate to very high cytotoxic activity (IC₅₀ value 7.86–35.88 µM). However, the selectivity index of the compounds was low, less than 1–1.96. Among the synthesized compounds, compound 1b showed the highest cytotoxicity and selectivity against MCF7 cell lines. Compound 1b could be considered for further development to obtain more active and selective chemotherapeutic agents against breast cancer.

A change in biological properties of the SARS-CoV-2 virus can enhance its transmissibility and virulence, complicate the disease course, and reduce the effectiveness of anti-viral therapy and vaccination. We have studied 16 genetic lineages of the Omicron variant. The viral reproduction course was analyzed based on plaque morphology in the agar layer and the maximum titer in Vero E6 cells. BALB/c mice and Syrian hamsters were used as animal models. Viral load and infectious SARS-CoV-2 titer were determined in the nasal tissue and lungs. The severity of infectious process was assessed using histological methods. An increased plug size was observed in CH.1.1 and BQ.1.2.1 strains after six passages. This was due to substitutions D614G, H655Y, and N764K in the coronavirus S protein. The same changes in gene variants Gamma and BA.1 were caused by the substitution R682W, which is not present in lineages CH.1.1 and BQ.1.2.1. A similar substitution, namely R682P, was observed in the BA.5.1 strain. We characterized BA.1 (as a reference), BA.5.2, and XBB.3 strains in vivo as representatives of the main circulating genetic lineages. For the BA.1 strain, ID50 was 1.3 and 14 TCD50 in Syrian hamsters and BALB/c mice, respectively. An insignificant increase in the BA.5.2 virulence compared to that of BA.1 was noted (ID50 was 07. and 10 TCD50, respectively). The XBB.3 pathogenicity in laboratory animals is similar to that of BA.1 (ID50 was 1.8 and 15 TCD50, respectively). Experiments showed a consistent decrease in the virulence of Omicron strains compared to previously circulating SARS-CoV-2 variants. A co-evolutionary change in amino acid sequences, affecting the conformation of the coronavirus S protein and its surface epitopes in representatives of different genetic lineages, was noted. The emergence of potential proteolysis sites and alterations of the furin cleavage site have been observed in numerous Omicron coronavirus variants.

A new method for the synthesis of azido-propargyloxy derivatives of 1,3,5-triazine has been developed. The antibacterial activity against E. coli bacteria of propargyloxy substituted 1,3,5-triazines - 2,4,6-trispropargyloxy-1,3,5-triazine, 2-azido-4,6-bispropargyloxy-1,3,5-triazine and 2,4-diazido-6-propargyloxy-1,3,5-triazine and their hyperbranched polymers. It has been shown that the presence of an azide group in the compound directly affects the antibacterial activity. The cytotoxicity of these compounds against the M-HeLa, FetMSC and Vero cell lines was studied. The IC50 value was determined for low molecular weight compounds. It has been shown that hyperbranched polymers without azide groups don’t exhibit pronounced cytotoxicity and can be used in biomedical applications.

This work presents the results of a comprehensive physico-chemical and biological study of hu-mic substances samples – an extract of humic and fulvic acids. The performed loss on drying test showed a 22 times different dry matter content between EHS and FA. The morphology and dis-tribution of particles in the dry residue of the samples assessed using the methods of optical and digital microscopy demonstrated differences in the qualitative features of the microstructures of their surfaces and granulometries. Shimadzu X-ray fluorescence spectrometry revealed Si (8.1 and 1.7%), P (33.5 and 2.7%), S (4.3 and 59.5%), K (1.35 and 2.5%), Ca (10.9 and 3.2%), Mn (0.27 and 0.06%), Fe (11 and 0.05%), Cu (0.16 and 0.45%), Zn (0.06 and 0.02%) in the dry residues of the EHS and FA samples, respectively. A high intensity of the X-ray fluorescence signal for Fe atoms in the EHS sample was demonstrated. The FT-IR spectra for EHS and FA are characterized by simi-lar vibration frequencies that are characteristic of the chromone derivatives (1-benzopyran-4-one). The UV absorption spectrum is characterized by max = 281 nm for FA. The EHS solution showed a fluorescence maximum at em = 560 nm at ex = 280 nm. Using the DLS method, nanoparticles of 1 nm and 200 nm were detected in EHS and FA diluted solutions, which are likely to condition the biochemical and physical properties of humic acids. Using the Spiro-tox-test method, the absence of the toxic effect of humic acids on the cell model of ciliates Sp. am-bigua was established. When the cell model was incubated in a solution of a toxicant of the fluo-roquinolone group, a decrease in toxicity was demonstrated when diluted with the EHS solu-tion. The results of the study of the antiviral activity of EHS and FA showed that the study ob-jects in the culture of Vero-E6 cells, in doses non-toxic to cells, suppress the reproduction of the SARS-CoV-2 virus both in the study of the virucidal effect and in the study of the antiviral activ-ity according to the therapeutic and prophylactic model scheme of injection. The results obtained suggest that standardized drugs based on humic acids may open up new perspectives in their biomedical application as antiviral drugs.