FIG. 4.

GFP-tagged plasmids bearing hetR or hetF in one cell of a filament. Shown is light (left panel) and fluorescence (right panel) microscopy of UHM132, a hetR hetF deletion strain with hetR and gfp on plasmid pDR309 in a single cell of a filament in BG-11 medium (A); UHM103, a hetR deletion strain with plasmid pDR309 in a single cell of a filament in BG-11 medium (B); and UHM130, a hetF deletion strain with hetF and gfp on plasmid pDR310 in a single cell of a filament in BG11₀ medium (C). GFP fluorescence identifies cells that have the indicated plasmid. Carets indicate heterocysts.