Multiphoton laser scanning microscopy for four-dimensional analysis of Caenorhabditis elegans embryonic development.

Multiphoton laser scanning microscopy (MPLSM) enables the production of long timelapse recordings from live fluorescent specimens. 1047- and 900-nm excitation were used to image both a vital fluorescent membrane probe, FM 4-64, and a modified green fluorescent protein (GFP) in live Caenorhabditis elegans embryos. Automated four-dimensional (4D) data collection yielded individual recordings comprising thousands of images, each allowing analysis of all of the cell divisions, contacts, migrations, and fusions that occur during a span of several hours of embryogenesis.