Fig 1.

Phylogenetic stains. Fluorescent in situ hybridization (FISH) using rRNA‐targeted, fluor‐labelled oligonucleotide probes complementary to rRNA sequences to identify single microbial cells. DeLong et al. (1989).

A. Bacillus megaterium and Saccharomyces cerevisiae hybridized with a fluorescein labelled universal probe and a rhodamine labelled eukaryote probe simultaneously. Cells in the same field were visualized with phase contrast (left), and epifluorescence using fluorescein filters (centre), or rhodamine filters (right).

B. Bacillus megaterium and Saccharomyces cerevisiae hybridized with a fluorescein labelled eukaryote probe and a rhodamine labelled bacterial probe simultaneously, and visualized with phase contrast (left), or epifluorescence photographed using a double exposure of fluorescein and rhodamine filter sets (right).

C. Single‐cell fluorescence intensity of individual E. coli cells labelled with a fluorescein‐labelled universal probe as a function of growth (solid circles). RNA content (solid triangle) and RNA/DNA per cell (open triangle) versus growth rate are also shown. The open circles show the fluorescence intensity of cells hybridized with a fluorescein‐labelled, negative control probe that does not bind to rRNA. DeLong et al. (1989). [Color figure can be viewed at wileyonlinelibrary.com]