Detection of low-copy-number genomic DNA sequences in individual bacterial cells by using peptide nucleic acid-assisted rolling-circle amplification and fluorescence in situ hybridization

An approach is proposed for in situ detection of short signature DNA sequences present in single copies per bacterial genome. The site is locally opened by peptide nucleic acids, and a circular oligonucleotide is assembled. The amplicon generated by rolling circle amplification is detected by hybridization with fluorescently labeled decorator probes.