title: Selection and characterization of DNA aptamers specific for Listeria species.
abstract: Single-stranded (ss) DNA aptamers with binding affinity to Listeria spp. were selected using a whole-cell SELEX (Systematic Evolution of Ligands by EXponential enrichment) method. Listeria monocytogenes cells were grown at 37°C and harvested at mid-log phase or early stationary phase to serve as the targets in SELEX. A total of 10 unique aptamer sequences were identified, six associated with log phase cells and four with stationary phase cells. Binding affinity of the aptamers was determined using flow cytometry and ranged from 10% to 44%. Four candidates having high binding affinity were further studied and found to show genus-specific binding affinity when screened against five different species within the Listeria genus. Using sequential binding assays combined with flow cytometry, it was determined that three of the aptamers (LM6-2, LM12-6, and LM12-13) bound to one apparent cell surface moiety, while a fourth aptamer (LM6-116) appeared to bind to a different cell surface region. This is the first study in which SELEX targeted bacterial cells at different growth phases. When used together, aptamers that bind to different cell surface moieties could increase the analytical sensitivity of future capture and detection assays.
authors.affiliation: Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695, USA. Electronic address: soohsuh@gmail.com.
authors.forename: Soo Hwan
authors.initials: SH
authors.lastname: Suh
authors.affiliation: Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Hari P
authors.initials: HP
authors.lastname: Dwivedi
authors.affiliation: Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Soo Jung
authors.initials: SJ
authors.lastname: Choi
authors.affiliation: Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Lee-Ann
authors.initials: LA
authors.lastname: Jaykus
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D002470:Cell Survival; D008089:Listeria monocytogenes / Q000166:cytology* / Q000378:metabolism; D052156:SELEX Aptamer Technique / Q000379:methods*; D013045:Species Specificity; D013379:Substrate Specificity
chemical_list: D052157:Aptamers, Nucleotide
keywords: Aptamer; Listeria monocytogenes; Listeria spp.; Pathogen detection; SELEX