Hemagglutinin-neuraminidase Sequence and Phylogenetic Analysis of Two Newcastle Disease Virus Isolated from Chickens in Iran.

Newcastle disease is a highly contagious viral infection affecting many species of birds that can spread fast between poultry houses and cause a heavy economic burden on the poultry industry all around the world. Fusion and hemagglutinin-neuraminidase (HN) protein are important in the pathogenesis of the Newcastle disease virus (NDV). The HN protein is a critical viral protein with multiple functions and plays a key role in the formation of the virulence of NDV. Head of HN protein is responsible for receptor binding, neuraminidase activity. This study aimed to investigate the sequence homology of hemagglutinin-neuraminidase of two NDV isolates sampled from infected farms in Iran. The samples were collected from flocks that had been vaccinated by both types of live and killed vaccines for NDV. After isolation of NDV, the viruses were subjected to the polymerase chain reaction (PCR) amplification using two pairs of specific primers designed for the HN gene to amplify the complete HN gene (1730bp). Afterward, the PCR products were sequenced and analyzed by phylogenetic tree construction software. Based on the analysis, substantial sequence homology among Iranian isolates is within the range of 97.1-100%. Moreover, the sequence homology searching revealed a level of similarity between HN sequences of Iranian isolates and the HN sequences from other countries, particularly Asian ones. For instance, a high homology ratio (95.34%) was found between Iranian isolates and the sequences registered on online molecular databases from China. Based on phylogenetic analysis, the NDV isolates belong to the VIId genotype. Finally, it can be concluded that monitoring the circulation of NDVs among poultry and other birds can help to obtain an insight into the evolution of NDVs and control of panzootic viruses in the future.

Computational studies on the interactions of glycine amino acid with graphene, h-BN and h-SiC monolayers.

In the present work, the adsorption of glycine amino acid and its zwitterionic form onto three different hexagonal sheets, namely graphene, boron-nitride (h-BN) and silicon carbide (h-SiC), has been investigated within the framework of Density Functional Theory (DFT) calculations. The energetics and geometrical parameters of the considered systems have been explored at the GGA-PBE level in combination with Grimme's empirical dispersion corrections with Becke-Johnson damping, the DFT-D3(BJ) method. Based on the obtained results, we found that both the glycine molecule and its zwitterionic conformation tend to be chemisorbed onto the surface of h-SiC (Eads ranges from -1.01 to -1.319 eV) while the types of interactions are recognized to be of non-covalent nature for the case of graphene (Eads ranges from -0.121 to -0.345 eV) and h-BN (Eads ranges from -0.103 eV to -0.325 eV) systems. Moreover, the empirical dispersion corrections applied in these calculations significantly improved the results and confirmed the crucial role of dispersion corrections in obtaining reliable geometries and adsorption energies. Our findings revealed that the electronic properties of the considered systems did not change during the adsorption process and these monolayers preserve their inherent electronic properties as they interact with the glycine molecule. Using the SMD implicit solvation model, the effect of solvation has also been evaluated by re-optimizing the structures within a medium with a dielectric constant of 78.39 (liquid water) and it has been shown that the strength of the interaction between the glycine conformers and hexagonal sheets has decreased. The accuracy of the obtained values has been evaluated by some benchmark calculations at the hybrid PW6B95 level of theory and reasonable consistency is found between the results of the PBE-D3 method and our benchmark system. In summary, h-SiC exhibited the highest affinity toward glycine conformers and gained an important edge over other monolayers. Our findings would actively encourage experimentalists to explore the potential applications of these materials in drug delivery, biofunctionalization of nanostructured monolayers as well as electronic and nanosensor devices.