[
International Worm Meeting,
2009]
Cell to cell interactions play critical roles in early embryogenesis, therefore, it is very important to have information about the arrangements of cells, cell shapes and the contact among them. We have been developing a computer system to create cell shape models from a time series of confocal microscopic images of the embryo whose plasma membrane is stained with a vital fluorescent dye or is marked with a fluorescent protein. This system consists of two subsystems. In the first step, cell shapes are automatically calculated by a seeded region growing algorithm from a 3D image and a set of seed point coordinates. Manual editing of the seed coordinates is required and is assisted by its graphical user interface. The second step is an active balloon model under gradient vector flow executed on a PC cluster system. This step removes the bumps of cell shapes derived from image noises. Consequently, cell-to-cell contacting areas can be quantified. We recorded images of OD58, the strain expressing GFP targeted to the plasma membrane, with a multiphoton confocal microscope. We used glass bottom dishes to avoid variable pressure from coverslips. We could record for 1.5 hours from one cell stage on the condition that the embryos continued the development and hatched successfully after the recording. Ten normal embryos were recorded and their cell shape models were built. We analysed the time course of each cell-to-cell contacting area by fitting a line to its graph and found that some of them increased or decreased consistently from embryo to embryo and others were variable in this respect. This suggested that some part of cellular arrangement was intrinsically variable and that the consistency of cell-to-cell contacts was not necessary to be complete for normal embryogenesis. We are improving the system more, and plan to apply this system to compare the cellular arrangements and the cell-to-cell contacts among mutant embryos and the embryos from other species closely related to C. elegans.