Dual labeling with green fluorescent proteins for confocal microscopy

We report a dual labeling technique involving two green fluorescent protein (GFP) variants that is compatible with confocal microscopy. Two lasers wer e used to obtain images of (i) mixed cultures of cells, where one species c ontained GFPuv and another species contained GFPmut2 or GFPmut3, and (ii) a single species containing both GFPuv and GFPmut2 in the same cell, This me thod shows promise for monitoring gene expression and as a nondestructive a nd in situ technique for confocal microscopy of multispecies biofilms.