Re: red sensitive PMT, small things
Mario Roederer (ROEDERER@Darwin.Stanford.EDU)
Mon, 19 Jun 1995 22:14:17 -0700 (PDT)
We have used a red-sensitive PMT, but not for Cy5 or PAC or TR... but
for a dye that's further out (at 780 nm). It improved signal to
background about 5-fold over the standard PMTs. (Immunofluorescence staining).
I have done FACS on very small things... but less than 0.2 microns!
Wow. In any case, we found that using log side scatter was a
considerably better trigger parameter than FS. In Bob Murphy's lab, we
used to centrifuge our sheath fluid at 20,000 x g to remove
particulates. This reduced the "background" event rate considerably.
Here at Stanford, I did FACS on myxococcus xanthus (an enormous 1 x 6
microns), using log side scatter--we did not have to treat the sheath
fluid specially. In both cases, the forward scatter signal was
basically meaningless. In both cases, we could easily detect
fluorescence (either fluorescein or rhodamine).
mr
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