title: In vitro selection of Escherichia coli O157:H7-specific RNA aptamer.
abstract: Escherichia coli (E. coli) O157:H7 is a major foodborne pathogen that causes life-threatening symptoms in humans worldwide. To rapidly and properly identify the pathogen and avoid its toxic effects, ligands which can directly and specifically bind to the virulent E. coli O157:H7 serotype should be identified. In this study, a RNA aptamer-based ligand which can specifically distinguish the pathogen E. coli O157:H7 from others was developed by a subtractive cell-SELEX method. To this end, an RNA library was first incubated with the E. coli K12 strain, and the RNAs binding to the strain were discarded. The precluded RNAs were then used for the selection of O157:H7-specific aptamers. After 6 rounds of the subtractive cell-SELEX process, the selected aptamer was found to specifically bind to the O157:H7 serotype, but not to the K12 strain. This was evidenced by aptamer-immobilized ELISA, real-time PCR analysis, or an aptamer-linked precipitation experiment. Importantly, the isolated RNA aptamer that distinguishes between the virulent serotype and the nonpathogenic strain specifically bound to an O157:H7-specific lipopolysaccharide which includes the O antigen. This novel O157:H7-specific aptamer could be of potential application as a diagnostic ligand against the pathogen-related food borne illness.
authors.affiliation: Department of Molecular Biology, Institute of Nanosensor and Biotechnology, Dankook University, Yongin, Republic of Korea.
authors.forename: Young Ju
authors.initials: YJ
authors.lastname: Lee
authors.forename: Seung Ryul
authors.initials: SR
authors.lastname: Han
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Maeng
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Cho
authors.forename: Seong-Wook
authors.initials: SW
authors.lastname: Lee
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000302:isolation & purification*; D001483:Base Sequence; D019453:Escherichia coli O157 / Q000145:classification / Q000302:isolation & purification*; D008024:Ligands; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D019081:O Antigens / Q000302:isolation & purification; D052156:SELEX Aptamer Technique
chemical_list: D052157:Aptamers, Nucleotide; D008024:Ligands; D019081:O Antigens