On 8 Feb 1995, Belhumeur Pierre wrote:
> I know that people working with pombe use phloxin B in their plates when
> screening for, say, suppression at high temp: it facilitates the
> discrimination between viable colonies from those who grew a bit and then
> die...The stain concentration with pombe is I believe 1 in 2000 of a 0.5%
> stock solution. Has anyone tried it with cerevisiae? And then, should one
> use the same conc.? Viable colonies should be white if I get it right
> (oxydize the stain)? ...
While I have never used Phloxin B (aka Magdala Red) on S.
cerevisiae, so I don't have the info that Pierre wants, I wanted to set
the record straight on how this dye works. Phloxin B is the opposite of a
vital stain. That is it selectively stains dead cells. Somehow live
cells are able to exclude this dye and thus are not stained. As Pierre
said, sick (dead) colonies are stained and healthy (live) colonies are
not. In practice, healthy colonies are probably going to come out light
pink and sick ones will be darker shades of red. Just my 2 cents worth.
Mike Moser Tel: 206-543-5354
Department of Biochemistry SJ-70 FAX: 206-685-1792
University of Washington moser at u.washington.edu
Seattle, WA 98195 Make peace my beast is yeast