Surgical Removal of a Complex Sensory Organ in Highly Regenerative Ctenophores

The ctenophore Mnemiopsis leidyi is a classic animal model of whole-body regeneration. Increased tractability for many laboratory techniques and their phylogenetic placement as the likely sister group to the remaining Metazoa has led to a recent renewal of scientific interest in working with ctenophores. They can regenerate any missing organ or cell type, including complete whole-body regeneration from a fragment as small as ~15% of the body, over the course of a few days. Like most ctenophores, M. leidyi have an aborally located, gravity-sensing organ that links sensory input to motor output to control their body position and orientation. This protocol demonstrates surgical removal of the aboral organ (AO) complex and associated structures in M. leidyi along with culturing, handling, and mounting methods appropriate to image the processes of wound healing and regeneration that take place in the following hours to days. These straightforward techniques are broadly adaptable to different experimental paradigms and laboratory contexts.