IN-SITU PCR FOR VISUALIZATION OF MICROSCALE DISTRIBUTION OF SPECIFIC GENES AND GENE-PRODUCTS IN PROKARYOTIC COMMUNITIES

Obtaining information on the genetic capabilities and phylogenetic aff inities of individual prokaryotic cells within natural communities is a high priority in the fields of microbial ecology, microbial biogeoch emistry, and applied microbiology, among others. A method for prokaryo tic in situ PCR (PI-PCR), a technique which will allow single cells wi thin complex mixtures to be identified and characterized genetically, Is presented here. The method involves amplification of specific nucle ic acid sequences inside intact prokaryotic cells followed by color or fluorescence detection of the localized PCR product via bright-field or epifluorescence microscopy, Prokaryotic DNA and mRNA were both used successfully as targets for PI-PCR. We demonstrate the use of PI-PCR to identify nahA-positive cells in mixtures of bacterial isolates and in model marine bacterial communities.