2 replies to this topic

[tezuka]

When i fix the biofilms with glutaraldehyde and stain it with acridine orange, i expect it to turn red but in some biofilm it turns green. why is this so? what makes the color change?

[HomeBrew]

Acridine orange is a metachromatic dye -- when it intercalates with DNA it fluoresces green (525nm), and when it interacts with RNA (by electrostatic attraction) it fluoresces red (>630nm).

[casandra]

HomeBrew, on 20 January 2011 - 06:59 AM, said:

Acridine orange is a metachromatic dye -- when it intercalates with DNA it fluoresces green (525nm), and when it interacts with RNA (by electrostatic attraction) it fluoresces red (>630nm).

yup, green but only when it's bound to double-stranded DNA....red for SS DNA so we can also use it as a measure of DNA denaturation or fragmentation in cells...

Edited by casandra, 20 January 2011 - 09:24 AM.