title: Caenorhabditis elegans body mechanics are regulated by body wall muscle tone.
abstract: Body mechanics in the nematode Caenorhabditis elegans are central to both mechanosensation and locomotion. Previous work revealed that the mechanics of the outer shell, rather than internal hydrostatic pressure, dominates stiffness. This shell is comprised of the cuticle and the body wall muscles, either of which could contribute to the body mechanics. Here, we tested the hypothesis that the muscles are an important contributor by modulating muscle tone using optogenetic and pharmacological tools, and measuring animal stiffness using piezoresistive microcantilevers. As a proxy for muscle tone, we measured changes in animal length under the same treatments. We found that treatments that induce muscle contraction generally resulted in body shortening and stiffening. Conversely, methods to relax the muscles more modestly increased length and decreased stiffness. The results support the idea that body wall muscle activation contributes significantly to and can modulate C. elegans body mechanics. Modulation of body stiffness would enable nematodes to tune locomotion or swimming gaits and may have implications in touch sensation.
authors.affiliation: Department of Mechanical Engineering, Stanford University Schools of Engineering and Medicine, Stanford, California, USA.
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Petzold
authors.forename: Sung-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Pierre
authors.initials: P
authors.lastname: Ponce
authors.forename: Clifton
authors.initials: C
authors.lastname: Roozeboom
authors.forename: Chloé
authors.initials: C
authors.lastname: Powell
authors.forename: Miriam B
authors.initials: MB
authors.lastname: Goodman
authors.forename: Beth L
authors.initials: BL
authors.lastname: Pruitt
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D049628:Body Size / Q000187:drug effects / Q000528:radiation effects; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D018679:Cholinergic Agonists / Q000494:pharmacology; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D007978:Levamisole / Q000494:pharmacology; D008027:Light; D055595:Mechanical Phenomena; D009118:Muscimol / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects / Q000528:radiation effects; D009126:Muscle Relaxation / Q000187:drug effects / Q000528:radiation effects; D009132:Muscles / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D010264:Paraplegia / Q000139:chemically induced / Q000503:physiopathology
chemical_list: D018679:Cholinergic Agonists; D058785:GABA-A Receptor Agonists; D009118:Muscimol; D007978:Levamisole