given the size of the embryo vs the diameter of the orifice, you probably are severely disturbing the drop formation process. An old (sorry Dick) article by Dick Stovell, Len and others has demonstrated that even when sorting normal cells, i. e. at much more favourable ratios of cell diameter vs orifice diameter. Saverio Alberti Head, Unit of Experimental Oncology Department of Cell Biology and Oncology Consorzio Mario Negri Sud 66030 Santa Maria Imbaro (Chieti), Italy Phone: (39) 872-570.293 FAX: (39) 872-578.240 E-mail: alberti@cmns.mnegri.it On Mon, 8 Mar 1999, Wayne Green wrote: > > An investigator here wants to sort C. elegans embryos expressing > GFP. The embryos are anywhere between the 28 cell to 600 cell stage with > most closer to the smaller size. Each embryo is roughly 50x30 microns, > ellipsoid in shape with a fairly rigid shell encasing the embryo. We are > told that the embryos are relatively resistant to physical trauma. > We have run these on a Vantage with a 100 micron tip (no Macro Sort) > and can detect the GFP expressing embryos. Our problem arises with the > sorting; if we sort 40,000 GFP positive embryos, one only finds about 100 in > the collection tube. The good news is that those 100 are healthy in that > they grow normally following the sorting process. The question is, > what might cause this abysmal sorting efficiency? When we sort "normal" > cells like murine stem cells, lymphocytes, etc. we get very good recovery > and purity. If there is anyone out there with experience sorting something > like this I would greatly appreciate your suggestions. > > Thanks > > Wayne F. Green, Ph.D. > HCI Flow Cytometry Core Lab > wayne.green@hci.utah.edu > >
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