In Vitro Selection of RNA Aptamer Specific to Salmonella Typhimurium

Abstract

Salmonella is a major foodborne pathogen that causes a variety of human diseases. Development of ligands directly and specifically binding to the Salmonella will be crucial for the rapid detection of, and thus for efficient protection from, the virulent bacteria. In this study, we identified a RNA aptamer-based ligand that can specifically recognize Salmonella Typhimurium through SELEX technology. To this end, we isolated and characterized an RNase-resistant RNA aptamer that bound to the OmpC protein of Salmonella Typhimurium with high specificity and affinity (Kd ~ 20 nM). Of note, the selected aptamer was found to specifically bind to Salmonella Typhimurium, but neither to Gram-positive bacteria (Staphylococcus aureus) nor to other Gram-negative bacteria (Escherichia coli O157:H7). This was evinced by aptamer-immobilized ELISA and aptamer-linked precipitation experiments. This Salmonella species-specific aptamer could be useful as a diagnostic ligand against pathogen-caused foodborne sickness.

Aptamers against pathogenic microorganisms

“…Several modified 2′-F-RNA aptamers against the outer membrane protein, OmpC, of S. Typhimurium were described in (Han & Lee, 2013). One aptamer, I-2, possessed high affinity to the target protein ( K d  = 20.27 nM) and, in contrast to the other obtained aptamers, was able to bind intact S. typhimurium cells.…”

Nucleic Acid Aptamers: Research Tools in Disease Diagnostics and Therapeutics

“…Although, traditional antibody based methods are quite sensitive in some cases, the demand for robust aptamer technology is quite high. RNase resistant RNA aptamer was selected against OmpC protein of Salmonella typhimurium with high affinity (Kd: 20 nM) and specificity [36]. It did not show binding with any other Gram-negative or Gram-positive bacteria.…”

Oligonucleotide aptamers: promising and powerful diagnostic and therapeutic tools for infectious diseases

“…This selected aptamer specifically binds to S. Typhimurium but not to gram-positive bacteria ( S. aureus ) or to other gram-negative bacteria ( E. coli O157:H7). 28 Several groups have used whole-cell SELEX to identify ss-DNA aptamers binding to S. Typhimurium, Salmonella Paratyphi and Salmonella enterica serovar Enteritidis ( S. Enteritidis) for Salmonella detection. [29][30][31][32][33][34][35] These aptamers binding to the whole cell of Salmonella were conjugated to nanomaterials such as gold nanoparticles (AuNPs) and fluorescent nanoparticles as probes, magnetic nanoparticles (MNPs) as concentration elements, or loaded onto SWCNTs and reduced graphene oxide (rGO).…”