From: James W. Jacobberger (jwj@po.cwru.edu)
Date: Thu Oct 12 1995 - 14:08:24 EST
Gerard, David Here's my two-cents. To analyze rodent malaria cell cycles which generally include G1 parasites that multiply infect red blood cells (thus giving peaks at 1N, 2N, 3N, ...~8N plus S phase component from 1N to 8N, we were up against a similar problem, I think. We initially utilized the graph and weigh method which I felt was quite good (S phase was a box with a height equal to the interpeak height). ~1986, reviewers criticized this, stating that we were too sophisticated (I think they meant computer literate) to get away with such an inexpensive analysis. So... I waited for Modfit from Verity House. This program allows you to build almost any model you want, including models that fit log distributed mammalian DNA histograms. The malaria work was eventually published using a multi-peak model that agreed with the results of the cutting and weighing (Jacobberger, Horan, Hare, Cell Prolif. 25:431-445, 1992). An example of a log DNA data fit can be seen in Rorke & Jacobberger, Exptl. Cell Res. 216:65-72, 1995. Unless there is something I don't understand about plant DNA distributions (which could be the case), I would guess that Modfit would handle the analysis. Then again, cutting out the peaks and weighing them doesn't cost much, especially if a student performs the analysis. Jake >Gerard: > >I periodically try to get software companies (or anyone else) interested in >writing programs for this purpose -- cell cycle analysis programs capable of >dealing with log distributions, multiple peaks, and background subtraction. >So far (as far as I am aware) there has been resounding silence. We print >out the distributions using something like Sigmaplot, enlarge them, cut out >the peaks, and weigh them. This apparently hokey approach is quite accurate >and was originally developed for finding the proportion of ribosomes in the >various 2-mer, 3-mer,4-mer, etc., peaks found in sucrose gradient analysis >of polyribosomes. Hey, maybe there's another application for the software7!? > >Good luck > >David > > > > >At 09:34 PM 10/10/95 -0500, you wrote: >>Dear colleagues, >> >>I'm working on DNA endoreduplication in maize nuclei, analyzing the >>tissue with a Coulter Epics flow cytometer/MDADSII. I want to calculate >>the percent nuclei in each individual C class to see how >>endoreduplication progresses as the tissue get older--e.g. how many >>nuclei are in the higher C classes over time. Are there any statistical >>programs to determine the number of cells/percentage of cells in each >>individual C class/peak? >> >>Thanks in advance, >> >>Gerard Engelen-Eigles >>Dept. Agronomy, university of MN, St. Paul, MN >>enge0019@gold.tc.umn.edu >> >> > > >============== >David Galbraith >Professor of Plant Sciences >University of Arizona >303 Forbes Building >Tucson AZ 85721 >Phone (520) 621-9153 >FAX (520) 621-7186 James (Jake) Jacobberger Associate Professor 216-368-4645 phone 216-368-3432 fax
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