The role of cytoskeletal mechanics in conferring wound resilience in the giant single-celled ciliate Stentor coeruleus*

Healing membrane wounds is critical for homeostasis and survival, especially in free-living single-celled organisms. The giant single-celled ciliate Stentor coeruleus is capable of healing extreme wounds. It has one of the highest healing rates among living organisms. We hypothesize that the Stentor cytoskeleton plays a vital role not only in wound healing but also in conferring wound resilience. We flow cells through a microfluidic constriction to evaluate their wounding characteristics. The wounded cells fail to recover their aspect ratio post constriction because of plasma membrane rupture and/or spillage of the cytoplasm. We find that the wounding regime depends on the dimensionless parameter D*, which is the cell diameter relative to the constriction width. Large D* increases the likelihood of wounding. Destabilization of the microtubule ribbons by nocodazole softens the cells while stabilizing them by taxol stiffens the cells, as indicated by measurements of the transit time of the cells through the constriction. In both drug treatments, the probability of wounding is higher than in untreated cells. This result suggests that, under the conditions assessed, the native microtubule arrangement might already confer an optimal wound resilience in the giant cell Stentor.