It is true that fluorescein photobleaches more rapidly than Texas Red.
However, the method of visualization of your probes is also important.
If you have a conventional widefield microscope equipped with an arc lamp
and you are viewing the probes through the eyepieces of the microscope,
some people find fluorescein to appear brighter, as our eyes are more
sensitive to green than red. If you are using a CCD camera or
photographic film to visualize your probes, however, Texas Red might
appear brighter because CCD cameras and film have better spectral
response to the red than the green. If you are using a confocal
microscope equipped with an argon ion or krypton/argon ion laser,
fluorescein will probably be the brighter probe, because it is more
efficiently excited by the laser than Texas Red, and the photomultiplier
tubes used to detect the emission signal are more sensitive to green than
To: fluorpro @ net.bio.net at smtp at CCMAIL
cc: (bcc: Jennifer Kramer)
From: ming @ msvax.mssm.edu at smtp at CCMAIL
Date: 05/11/96 04:07:00 PM
Subject: Re: Texas red vs FITC
In article <318FC394.7915 at sct.gu.edu.au>, "H. Woo" <h.woo at sct.gu.edu.au>
writes: >Has anyone observed that the red fluorescence from texas
red-labelled >probes is easier to see than the green fluorescence from
FITC-labelled >probes in whole cell hybridization?
FITC decays faster than others. If you do not use double labelling, cys3
from Amersham is the best.