Re: DNA dyes

Posted by Mario-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/DNA-dyes-tp592122p592127.html

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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 [phone]

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