jdubb@bucsf.bu.edu (jay dubb) (04/22/91)
I am posting this for a friend of mine who doesn't have access to USENET, so please respond directly to mlevin@jade.tufts.edu. I am working on early sea-urchin development. One of the things I have to do often is to construct a graph of division versus time in urchin eggs, during the 1st two cell divisions. What I've been doing so far, is to take samples from the culture every 10 minutes, get it under a microscope, and score a large number of cells (write down whether each cell is in the 1-cell stage, 2-cell stage, or 4-cell stage). These data are processed to arrive at a single number, expressing how many cell divisions have taken place in that culture, and this is plotted against time (for many measurements) to arrive at a graph showing the time course of their synchronous mitotic divisions. As you may well imagine, this is very tedious stuff. I was wondering, if anyone has any ideas on how one can automate this procedure. That is, is there any chemical method that would allow me to take a sample of sea-urchin embryos and let me quantitate how many mitotic divisions have taken place within in it? For example, you can analyze copies of DNA, but this would be harder than just scoring them by hand. I have dreams of rigging something involving those optical densitometers that they use to estimate enzyme reaction rates, etc. - but it is not clear to me that 4-cell embryos will transmit light any differently than 1-cell ones. Are there any other methods out there? Maybe something involving staining the cell mebranes, etc. Any ideas? How do other people quantitate mitosis (perhaps in other organisms)? Ideas, or pointers to sources would be greatly appreciated. Mike Levin (mlevin@jade.tufts.edu)