TABLE 1.

Some of the fluorescent molecules used to study microorganisms by flow cytometry

Dye	Excitation wavelength (λmax) (nm)	Emission wavelength (λmax) (nm)	Ligand or substrate	Applications
TOTO-3	642	660	DNA, RNA	DNA quantification, cell cycle studies
SYTOX Green	504	525	DNA, RNA	Viability, DNA quantification
PI	536	625	DNA, RNA	Viability, DNA quantification, cell cycle studies
Ethidium bromide	510	595	DNA, RNA	DNA quantification, cell cycle studies
Hoechst 33258/33342	340	450	DNA (GC pairs)	Cell cycle studies
SYTO 13	488	509	DNA, RNA	Viability, DNA quantification, cell cycle studies
Mithramycin	425	550	DNA	Cell cycle studies
Pyronine Y	497	563	RNA	RNA quantification
FITC	495	525	Protein	Microbe detection
Texas Red (sulforhodamine isothiocyanate)	580	620	Protein	Microbe detection
Oregon Green isothiocyanate	496	526	Protein	Microbe detection
Indo-1	340	398–485	Ca2+	Ca2+ mobilization
Fura-2	340	549	Ca2+	Ca2+ mobilization
Fluor-3	469	545	Ca2+	Ca2+ mobilization
BCECF	460–510	520–610	pH	Metabolic variations
SNARF-1	510	587–635	pH	Metabolic variations
DIOC6(3)	484	501	Membrane potential	Antibiotic susceptibility, metabolic variations
Oxonol [DiBAC4(3)]	488	525	Membrane potential	Antibiotic susceptibility, metabolic variations
Rhodamine 123	507	529	Membrane potential (mitochondria)	Antibiotic susceptibility, metabolic variations
Fun-1	508	525–590	Yeast vacuolar enzyme activity	Yeast metabolic state
Nile Red	490–550	540–630	Lipids
Lectins	Depends on fluorochrome conjugated	Depends on fluorochrome conjugated	Membrane oligosaccharides	Cell wall composition, microbe detection
Fluorescently labeled oligonucleotides	Depends on fluorochrome conjugated	Depends on fluorochrome conjugated	Nucleotide sequences	Microbe identification
Calcofluor white	347	436	Chitin and other carbohydrate polymers	Fungal detection
Substrates linked to fluorochromes			Enzyme activities	Metabolic activity
Antibodies labeled with flurochormes			Antigens	Microbe detection