Nematode Autotomy Requires Molting and Entails Tissue Healing without Obvious Regeneration

Abstract

Autotomy in C. elegans, which results in the severing of the body into two fragments, has been observed as a response to late larval worm-star formation after exposure to a bacterial surface pathogen. It was found that autotomy can occur in both hermaphroditic and gonochoristic nematode species, and during either the L3 or the L4 molt. Severing was hypothesized to be driven by a ‘balloon-twisting’ mechanism during molting but was found to be independent of lethargus-associated flipping. Extensive healing and apparent tissue fusion were seen at the site of scission. No obvious regeneration of lost body parts was seen in either L4 or adult truncated worms. A variety of mutants defective in processes of cell death, healing, regeneration, responses to damage, stress or pathogens were found to be competent to autotomize. Mutants specifically defective in autotomy have yet to be found. Autotomy may represent a modification of the essential normal process of molting.

Regeneration and regengrow in multicellular animals derive from the presence of processes of organ metamorphosis and continuous growth in their life cycles

“…Nematodes have a fixed asymmetric segmentation and the final embryo at hatching looks like a miniature adult, with the exception of gonads. Nematodes include 58% species adapted to marine water while 42% are terrestrial but many species evolved complex parasitic cycles with some mutes but are incapable of any regeneration (Clarck, 1994; Hodgkin, 2019). Although many extant nematodes transit through 4–6 larval stages, they simply increase in size and do not go through large anatomical changes, so their genome is likely not designated or programmed for regeneration after injury or body loss (Figures 2, 3 and 8).…”