golshid javdani shahedin

Bovine Viral Diarrhea Virus (BVDV), which is prevalent in cattle, is the causative agent of one of the most economically important animal diseases. This infection poses a significant challenge to the cattle industry. Several studies have indicated the high prevalence of BVD virus in Iran. As there is no specific treatment for this infection, the best way to overcome the disease is the use of control and prevention strategies such as vaccination. Due to the high prevalence of BVDV in Iran, there is always the question of how to implement a program to address this challenge in order to reduce economic losses. This study aimed to present the analysis of BVDV epidemiological studies in Iran.

Management of severe acute respiratory syndrome coronavirus 2 in humans depends on the availability of vaccines or effective drugs. Studies have shown that angiotensin‑converting enzyme 2 (ACE2) is responsible for binding the viral spike glycoproteins to human cells. Melittin from the bee venom of Apis melifera is a peptide with antimicrobial activities.

In this study, important amino acid residues of ACE2 interacting with spike glycoproteins of the virus were described based on the ACE2‑spike–glycoprotein interface. This has been previously analyzed by Robson in crystal structures of the receptors and ligands. Flexible linkers and 31 amino acid residues from N‑terminal of ACE2 as coronavirus spike binding domains (SBDs) were added to 17 N‑terminal amino acids of melittin (the hydrophobic motif) to construct a hybrid peptide or M‑ACE2SBD. Then, secondary and tertiary structures of the peptide were predicted.

Docking of the hybrid peptide and coronavirus SBDs was carried out as well. Previous studies showed that toxicity and hemolytic activity of the melittin hydrophobic motif decreased in comparison to native melittin due to the lack of peptide binding to the exposed anionic lipids of the human cell membranes and hence the novel peptide can be recommended as an appropriate drug for clinical uses.

This study has hypothesized that 17 N‑terminal amino acids of the mutant melittin used in M‑ACE2SBD design are potentially hydrophobic and attached coronavirus‑2 through lipid envelope of the virus.

Bacteriophages are bacterial parasites. Unlike lytic bacteriophages, lysogenic bacteriophages do not multiply immediately after entering the host cells and may integrate their genomes into the bacterial genomes as prophages. Prophages can include various phenotypic and genotypic effects on the host bacteria. Enterococcus spp. are Gram-positive bacteria that cause infections in humans and animals. In recent decades, these bacteria have become resistant to various antimicrobials, including vancomycin. The aim of this study was to analyze genome of an enterococcal prophage.

In this study, Enterococcus faecium EntfacYE was isolated from biological samples and its genome was analyzed using next-generation sequencing method.

Overall, 254 prophage genes were identified in the bacterial genome. The prophage included 39 housekeeping, 41 replication and regulation, 80 structural and packaging, and 48 lysis genes. Moreover, 46 genes with unknown functions were identified. All genes were annotated in DNA Data Bank of Japan.

In general, most prophage genes were linked to packaging and structure (31.5%) gene group. However, genes with unknown functions included a high proportion (18.11%), which indicated necessity of further analyses. Genomic analysis of the prophages can be effective in better understanding of their roles in development of bacterial resistance to antibiotics. Moreover, identification and study of prophages can help researchers develop genetic engineering tools and novel infection therapies.

 Enterococcal infections are considered the most common nosocomial infections. Nowadays, enterococci show high resistance to common antibiotics, especially vancomycin. Vancomycin-resistant Enterococcus faecium is one of the most common nosocomial infections, which is included in the World Health Organization priority pathogens list for research and development of new antibiotics. In this case, we focused on the E. faecium EntfacYE genome and its antibiotic-resistant genes to understand the reasons that caused this bacteria to be resistant to antibiotics.

 In total, 25 enterococcal samples were isolated from patients' blood. Bacteriophages were isolated on a multidrug-resistant Enterococcus faecium EntfacYE in our previous study. In this study, the isolated E. faecium EntfacYE strain was verified using Sanger partial sequencing of the bacterial elongation factor Tu. EntfacYE strain was assessed for antibiotic resistance, and the bacterial genome was extracted and completely sequenced. The sequenced genome was analyzed, and the genes were annotated in the DNA Data Bank of Japan.

 Totally, EntfacYE genome subsystems included 23 various categories with 59 genes belonging to antimicrobial resistance genes, such a way that 49 antibiotic resistance genes were included in specific subsystems, while ten genes lacked specific subsystems. Moreover, cadmium, cobalt, copper, zinc, and mercury resistance genes were identified in the EntfacYE genome.

 In conclusion, studies on bacterial genomes help researchers to identify characteristics of common pathogens, including virulence and antibiotic-resistance genes, and hence better understand bacterial pathogenesis to provide novel solutions for the treatment of common infections.

Silver nanoparticles (Ag-NPs) are potent antimicrobial agents, which have recently been used in dentistry. The aim of the current study was to optimize antimicrobial activity of Ag-NPs used in preparing irreversible hydrocolloid impressions against three microorganisms of Escherichia coli, Streptococcus mutans and Candida albicans.

After assessing antimicrobial activity of the compound using disk diffusion method, three parameters of concentration of Ag-NPs (250-1000 ppm), ratio of hydrocolloid impression material powder to water (0.30-0.50) and time of mixing (20.0-60.0 s), affecting antimicrobial activity of irreversible hydrocolloid impression materials against the three microorganisms, were optimized. This combined process was successfully modeled and optimized using Box-Behnken design with response surface methodology (RSM). Decreases in colony number of E. coli, S. mutans and C. albicans were proposed as responses.

Qualitative antimicrobial assessments respectively showed average zone of inhibition (ZOI) of 3.7 mm for E. coli, 3.5 mm for S. mutans and 4 mm for C. albicans. For all responses, when the mixing duration and powder-to-water ratio increased, the circumstances (mixing duration of 59.38 s, powder-to-water ratio of 0.4 and Ag-NP concentration of 992 response) increased. Results showed that in optimum ppm, the proportion of decreases in colony numbers was maximum (89.03% for E. coli, 87.08% for S. mutans and 74.54% for C. albicans). Regression analysis illustrated a good fit of the experimental data to the predicted model as high correlation coefficients validated that the predicted model was well fitted with data. Values of R2Adj with R2Pred were associated to the accuracy of this model in all responses.

Disinfection efficiency dramatically increased with increasing of Ag-NP concentration, powder-to-water ratio and mixing time.