MALDI-TOF ANALYSIS OF POLYMERASE-CHAIN-REACTION PRODUCTS FROM METHANOTROPHIC BACTERIA

Polymerase chain reaction (PCR) assays were designed to amplify 56- an d 99-base regions of the pmoA gene from Methylosinus trichosporium OB3 b and Methylomicrobium albus BG8, two species of methanotrophic bacter ia that are of interest for monitoring bioremediation activity. The PC R product sizes are in a mass range that is accessible to analysis by MALDI-TOF mass spectrometry. A rapid purification procedure using comm ercially available reversed-phase cartridges was applied prior to MALD I-TOF analysis. A small aliquot (1.5%, 1.5 mu L) from a single 100-mu L PCR reaction was sufficient for reliable detection. No cross-amplifi cation products were observed when primers designed for one bacterial species were used with genomic DNA of the other species. The methodolo gy described here has potential to allow less expensive and faster cha racterization of the ability of microbial populations to destroy pollu tants in groundwater and soil at contaminated industrial sites.