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I've used DAPI on live cells, and they went through mitosis ok, but these
were just in the short term  (a couple of hours).  I've not managed to get
either DAPI or Hoescht to work so well on longer term cultures - probably as
everyone says because of the UV issue.

Michelle


On 12/3/08 22:09, "Mario Moronne" <[log in to unmask]> wrote:

> Search the CONFOCAL archive at
> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
> 
> Carl, Charles,
> 
> The response Charles described is to be expected using Hoechst, if UV
> (=< 405 nm) excitation is used. Same goes for DAPI, with the
> additional problem that DAPI requires permeabilized cells making it
> unsuitable for most live cell experiments.
> 
> I have not tried this but I am sure someone out there probably has,
> namely, multi-photon confocal either 2 P or 3 P to excite Hoechst,
> which is PM permeable. UV by itself will elicit radical generation
> and strand breaking. Hoechst being a minor groove DNA dye could lead
> to a lower risk of scission when using 2 P or 3 P to get excitation,
> and might pose less risk of collateral DNA damage including unwanted
> crosslinking.
> 
> Further, I would be interested to know whether Hoechst added to cells
> in culture with no light excitation and maintained through what would
> be a couple of passages would permit any cell division. I.E., does
> the dye+light abolish cell division or dye by itself?
> 
> Regards All,
> Mario
> 
> PS I know that MP illumination can really cook cells, too. Guys what
> about using DRAQ5 to watch mitosis?
> 
> 
>> Search the CONFOCAL archive at
>> http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
>> 
>> Dear all,
>> What is the consensus on using either DAPI or Hoechst staining on
>> live cells?  Are there effects on mitosis and/or chromosome movement?
>> Thanks,
>> 
>> Carl
>> 
>> Carl A. Boswell, Ph.D.
>> Molecular and Cellular Biology
>> University of Arizona
>> 520-954-7053
>> FAX 520-621-3709
>