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Hi Kevin,

 I use Sudan Black (from Humason's Animal Tissue Techniques). It is not
fluorescent itself and works wonders on quenching endogenous fluorescence,
including from blood. The only issue is that the staining is done in 70%
alcohol to keep the dye soluble. So depending on your other staining
conditions, it might not work for you. 

 

Good luck. 

 

Helen McBride

Helen J. McBride, Ph.D. 
Senior Scientist 
Inflammation Group 
Amgen 
One Amgen Center Drive MS:29-5-1 
Thousand Oaks, CA 91320-1799 
Phone: 805-313-5476 
Fax: 805-447-1982 
Email:[log in to unmask] 

 

  _____  

From: Confocal Microscopy List [mailto:[log in to unmask]] On
Behalf Of Rosemary White
Sent: Thursday, July 12, 2007 2:19 PM
To: [log in to unmask]
Subject: Re: quenching of Alexa633

 

Hi Kevin,

You could try toluidine blue or crystal violet, though I've only used these
to quench stains fluorescing in the yellow-green.  Or possibly basic fuschin
(from Schiff's), which will fluoresce in the green-yellow but I think is not
fluorescent with red excitation.  No experience with any of them on animal
cells....

cheers,
Rosemary

Dr Rosemary White               [log in to unmask]
CSIRO Plant Industry            ph.     02-6246 5475
GPO Box 1600                        fax.     02-6246 5334
Canberra, ACT 2601            
Australia




  _____  

From: Kevin Braeckmans <[log in to unmask]>
Reply-To: Confocal Microscopy List <[log in to unmask]>
Date: Thu, 12 Jul 2007 16:04:45 +0200
To: [log in to unmask]
Subject: quenching of Alexa633

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<http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal>  
Dear list,
 
We are using transferrin tagged with Alexa633 to label the clathrin-mediated
endocytosis pathway of living cells. We wanted to use trypan blue to quench
the fluorescence of the remaining Alexa-Tf on the cell membrane. However,
this does not seem to work, contrary to e.g. bodipy or fluorescein.
 
Do others also have found difficulties in quenching Alexa-dyes by tripan
blue? Does someone know an alternative quencher which might work?
 
Thanks for any suggestions,
 
Kevin
 
 
Kevin Braeckmans, Ph.D.
Lab. General Biochemistry and Physical Pharmacy
Ghent University
Harelbekestraat 72
9000 Ghent
Belgium
Tel: +32 (0)9 264.80.78
Fax: +32 (0)9 264.81.89