FIB-SEM Imaging of C Elegans Embryos Captured During First Cell Division

cssi_iCElegans

Gravid adult C elegans worms were dissected and fertilized embryos were collected in cellulose capillary tubes. These embryos were visually followed under a dissection microscope, and upon reaching a desired cell division state, were high-pressure frozen immediately. The frozen embryos were quick-freeze-substituted and prepared for FIB-SEM imaging. Raw image (8 bit tiff) stacks were collected at 3 nm lateral pixel sampling and 9 nm FIB step size, and later cropped, aligned, binned and contrast-inverted to yield isotropic image volumes used for segmentation workflows. Details of the methods are included in the manuscript Rahman MM et al, J Cell Biol 2019, titled - C. elegans pronuclei fuse after fertilization through a novel membrane structure.