Isolation of an Aptamer that Binds Specifically to E. coli |
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| Authors: | Soledad Marton Fernanda Cleto Marco Aurélio Krieger Josiane Cardoso |
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| Affiliation: | 1Instituto de Biologia Molecular do Paraná, Department of Research and Development, 3375 Professor Algacyr Munhoz Mader Street, Curitiba, Brazil;2Instituto Carlos Chagas, Laboratório de Genomica Functional, 3375 Professor Algacyr Munhoz Mader Street, Curitiba, Brazil;University of São Paulo, BRAZIL |
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| Abstract: | Escherichia coli is a bacterial species found ubiquitously in the intestinal flora of animals, although pathogenic variants cause major public health problems. Aptamers are short oligonucleotides that bind to targets with high affinity and specificity, and have great potential for use in diagnostics and therapy. We used cell-based Systematic Evolution of Ligands by EXponential enrichment (cell-SELEX) to isolate four single stranded DNA (ssDNA) aptamers that bind strongly to E. coli cells (ATCC generic strain 25922), with Kd values in the nanomolar range. Fluorescently labeled aptamers label the surface of E. coli cells, as viewed by fluorescent microscopy. Specificity tests with twelve different bacterial species showed that one of the aptamers–called P12-31—is highly specific for E. coli. Importantly, this aptamer binds to Meningitis/sepsis associated E. coli (MNEC) clinical isolates, and is the first aptamer described with potential for use in the diagnosis of MNEC-borne pathologies. |
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