Jackie Saleh writes: >...could someone recommend alignment beads for >bacterial sorting. My >instrument is a FacsVantage. In my experience, if you can trigger successfully on forward scatter signals from 0.5 um polystyrene beads, you can trigger successfully on forward scatter signals from bacteria such as Staphylococcus aureus, Escherichia coli, or anything bigger. This may require some adjustment of your scatter optics. I am assuming you will be using a water-cooled laser; scatter sensitivity tends to be better because there is usually less optical noise on a water-cooled than on an air-cooled laser (which has nothing to do with the cooling; it reflects a difference in power supply design). If you are using 488 nm excitation and measuring green fluorescence (which you would do for GFP, and I'm guessing that a high-tech pharmaceutical company would be at least as interested in sorting bacteria on the basis of GFP fluorescence as on any other basis), you can use 0.5 um Polysciences yellow-green calibration beads; they have very good (2% or lower) CV's in both forward scatter and fluorescence. These beads also come in smaller sizes (near 0.25 um); if you can trigger on those, you're really in good shape. -Howard
This archive was generated by hypermail 2b29 : Wed Apr 03 2002 - 11:55:35 EST