Green fluorescent protein as a marker for conditional gene expression in bacterial cells.

To date, the majority of studies of bacterial gene expression have been carried out on large communities, as techniques for analysis of expression in individual cells have not been available. Recent developments now allow us to use reporter genes to monitor gene expression in individual bacterial cells. Conventional reporters are not suitable for studies of living single cells. However, variants of GFP have proved to be ideal for the study of development, cell biology, and pathogenesis and are now the reporters of choice for microbial studies. In combination with techniques such as DFI and IVET and the use of flow cytometry and advanced fluorescence microscopy, the latest generation of GFP reporters allows the investigation of gene expression in individual bacterial cells within particular environments. These studies promise to bring a new level of understanding to the fields of bacterial pathogenesis and environmental microbiology.