From: Hazel Davey (hlr@aber.ac.uk)
Date: Thu Jul 02 1998 - 04:41:55 EST
Robert Pyle wrote: > > With regards to sizing with the flows: From the earliest days of my flow > experience I seem to remember being told and experiencing the difference between > say a 10 micron bead and a 10 micron cell. I use to play with the Polyscience With microorganisms (M. luteus and 3 yeast- mean size range ~1 to ~7 um) we found that the light scattering of a cell of a given size was about 76% of what would be expected from a (Dynal) bead of the same diameter (Davey HM, Davey CL, and Kell DB: On the determination of the size of microbial cells using flow cytometry. In: Flow cytometry in microbiology, Lloyd D (ed.). Springer-Verlag, London, 1993, pp. 49-65.) However, this was performed on a Skatron flow cytometer and although we haven't repeated the (vey long and tedious) experiments on our newer flow cytometers I suspect that a) cell size is still underestimated by bead calibration and b) the calibration factor differs from instrument to instrument and between cell types. To keep things simple the organismsms we chose to do the work were all fairly spherical (as bugs go). If the cells used are markedly non-spherical the differences between the bead-predicted size and true size may be even greater. The calibration factor also depended to some extent on the buffer that the cells had been suspended in prior to analysis, and we found that sizes could not be accurately predicted in the case of fixed cells. Haze ---------------------------------------------------------- | Hazel Marie Davey hlr@aber.ac.uk | |Sefydliad y Gwyddorau Biolegol*Inst. Biological Sciences| |Prifysgol Cymru * University of Wales| | ABERYSTWYTH, Ceredigion, CYMRU / WALES SY23 3DD | | http://pcfcij.dbs.aber.ac.uk/index.htm |
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