BD CompBeads + infra-red emitting fluorochromes

Dear Flowers


My first question is about the use of BD CompBeads to determine the
compensation values as replacement for single-stained cells in a LSRII using
the FACSDiva's compensation process. From what I understand, these beads are
small and therefore the settings for scatter values needed to see them are
quite different from cells (my sample is bone marrow). How I should proceed
during the compensation process? Should I set FSC and SSC based on my sample
and cross the fingers that I am still able to identify these beads? Or
should I run the compensation process according to scatter values more
adequate to see the beads and go back to the scatter settings of my sample
after the compensation process is done? 


The second question is related to the use of infra-red emitting
fluorochromes. According to BD infrared detection requires a Hamamatsu R3896
PMT (a red-sensitive detector). This applies to fluorochromes such as PE-Cy7
and APC-Cy7. Therefore I am assuming that the LSRII red trigon has such
PMTs (??). But what about the other detectors? What kind of PMTs are there?
To be more specific for the application I have in mind: I want to use
Qdot-800 using the UV laser, therefore I need to know what kind of detectors
are used for the UV trigon, and in case of there is not a Hamamatsu R3896
how critical is this fact for the detection of Qdot-800. 


Thanks


Jose


Jose Diaz-Romero

Institute of Pathology

University of Bern

Switzerland