Synthesis, role in antibacterial, antiviral, and hazardous effects of silver nanoparticles

Viral pathogen infections pose a major global health challenge: the emergence of bacteria and strains of viruses that are resistant to conventional antibiotics and antivirals, and undesirable side effects due to their long-term use, are slowing the use of many antiviral therapies. As a potentially useful tool in the prevention of various pathogens, silver nanoparticles have already demonstrated their potential as an effective antiviral agent thanks to their unique physical and chemical properties. Silver nanoparticles offer an excellent opportunity for new antiviral therapies as they can attack a wide variety of viruses. It has been suggested that AgNPs induces reactive oxygen species and free radicals that induce apoptosis, which leads to cell death and prevents cell replication and cell wall destruction, and smaller nanoparticles have also been shown to be more toxic than larger particles. The toxicity of AgNP depends on the size, concentration, pH of the medium and the duration of exposure to the pathogen. This review examines the antimicrobial mechanisms, deleterious effects, and synthesis of AgNPs.

Complete Genome Sequencing of Field Isolates of Peste des Petits Ruminants Virus from Tanzania Revealed a High Nucleotide Identity with Lineage III PPR Viruses.

Peste des petits ruminants virus (PPRV) causes a highly devastating disease of sheep and goats that threatens food security, small ruminant production and susceptible endangered wild ruminants. With policy directed towards achieving global PPR eradication, the establishment of cost-effective genomic surveillance tools is critical where PPR is endemic. Genomic data can provide sufficient in-depth information to identify the pockets of endemicity responsible for PPRV persistence and viral evolution, and direct an appropriate vaccination response. Yet, access to the required sequencing technology is low in resource-limited settings and is compounded by the difficulty of transporting clinical samples from wildlife across international borders due to the Convention on International Trade in Endangered Species (CITES) of Wild Fauna and Flora, and Nagoya Protocol regulations. Oxford nanopore MinION sequencing technology has recently demonstrated an extraordinary performance in the sequencing of PPRV due to its rapidity, utility in endemic countries and comparatively low cost per sample when compared to other whole-genome (WGS) sequencing platforms. In the present study, Oxford nanopore MinION sequencing was utilised to generate complete genomes of PPRV isolates collected from infected goats in Ngorongoro and Momba districts in the northern and southern highlands of Tanzania during 2016 and 2018, respectively. The tiling multiplex polymerase chain reaction (PCR) was carried out with twenty-five pairs of long-read primers. The resulting PCR amplicons were used for nanopore library preparation and sequencing. The analysis of output data was complete genomes of PPRV, produced within four hours of sequencing (accession numbers: MW960272 and MZ322753). Phylogenetic analysis of the complete genomes revealed a high nucleotide identity, between 96.19 and 99.24% with lineage III PPRV currently circulating in East Africa, indicating a common origin. The Oxford nanopore MinION sequencer can be deployed to overcome diagnostic and surveillance challenges in the PPR Global Control and Eradication program. However, the coverage depth was uneven across the genome and amplicon dropout was observed mainly in the GC-rich region between the matrix (M) and fusion (F) genes of PPRV. Thus, larger field studies are needed to allow the collection of sufficient data to assess the robustness of nanopore sequencing technology.