Chapter 10 Laser Killing of Cells in Caenorhabditis elegans

Abstract

This chapter discusses the laser killing of cells in Caenorhabditis elegans. Individual cells can be killed in Caenorhabditis elegans by damaging them with a laser microbeam focused through the objective of a microscope. The laser beam is focused in three dimensions on a single spot in the field of view of a microscope. A cell of interest is aligned with the laser beam. Damage to the cell and adjacent structures can be visualized through the microscope during and after the operation. Identifying cells unambiguously is probably the most difficult part of the laser operation. Rigorous identification of a cell type can be accomplished by following cell lineages through embryonic or postembryonic divisions. When a laser microbeam is fired at a C. elegans nucleus, three things happen: deposition of energy in the nucleus, followed by transport, followed by energy-induced damage. Deposition places the energy with remarkable precision. Transport moves the energy from where it was deposited to other places. However, damage is the dark mystery and nothing is known about how laser energy destroys a C. elegans nucleus. Energy deposited in the irradiated nucleoplasm eventually takes the form of increased temperature and pressures, either of which can denature proteins, break DNA, and so on.