Biosensor for the specific detection of a single viable B. anthracis spore

摘要: A simple membrane strip-based biosensor for the detection of viable B. anthracis spores was developed and combined with a spore germination procedure as well nucleic acid amplification reaction to identify little one in less than 12 h. The is based on identification unique mRNA sequence from anthrax toxin activator (atxA) gene encoded plasmid, pXO1. Preliminary work relied plasmid vectors both E. coli thuringiensis expressing atxA gene. Once principle firmly established, vaccine strain used. After inducing outgrowth (Sterne strain), RNA extracted lysed cells, amplified using sequence-based (NASBA), rapidly identified by biosensor. While assay requires only 15-min time, overall process takes12 h spore, shortened significantly, if larger amounts are present. an oligonucleotide sandwich-hybridization format. It uses flow-through system immobilized probe that hybridizes target sequence. Signal provided when second has been coupled dye-encapsulating liposomes. dye liposomes then provides signal can be read visually or quantified hand-held reflectometer. detect 1.5 fmol mRNA. Specificity analysis revealed no crossreactivity closely related species such cereus, megaterium, subtilis, etc.