Evaluation of fixation methods for ultrastructural study of Caenorhabditis elegans embryos.

Various fixation methods for transmission electron microscopy (TEM) were tested on Caenorhabditis elegans embryos. By combining various techniques, using 3.4% chitinase in combination with 1% alpha-chymotripsin, we were able to establish a new fixation procedure that for the first time preserves both membranes and internal cellular ultrastructure of C. elegans embryos in different stages of development. This unique procedure will enable a hitherto unattainable standard for TEM research of C. elegans embryos. Sectioning of specific developmental stages fixed with this method allows a detailed study of ultrastructural aspects of embryogenesis.