title: Worms under Pressure: Bulk Mechanical Properties of C. elegans Are Independent of the Cuticle.
abstract: The mechanical properties of cells and tissues play a well-known role in physiology and disease. The model organism Caenorhabditis elegans exhibits mechanical properties that are still poorly understood, but are thought to be dominated by its collagen-rich outer cuticle. To our knowledge, we use a novel microfluidic technique to reveal that the worm responds linearly to low applied hydrostatic stress, exhibiting a volumetric compression with a bulk modulus, κ = 140 ± 20 kPa; applying negative pressures leads to volumetric expansion of the worm, with a similar bulk modulus. Surprisingly, however, we find that a variety of collagen mutants and pharmacological perturbations targeting the cuticle do not impact the bulk modulus. Moreover, the worm exhibits dramatic stiffening at higher stresses-behavior that is also independent of the cuticle. The stress-strain curves for all conditions can be scaled onto a master equation, suggesting that C. elegans exhibits a universal elastic response dominated by the mechanics of pressurized internal organs.
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey.
authors.forename: William
authors.initials: W
authors.lastname: Gilpin
authors.affiliation: Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey.
authors.forename: Sravanti
authors.initials: S
authors.lastname: Uppaluri
authors.affiliation: Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey. Electronic address: cbrangwy@princeton.edu.
authors.forename: Clifford P
authors.initials: CP
authors.lastname: Brangwynne
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism*; D003094:Collagen / Q000235:genetics / Q000378:metabolism*; D004548:Elasticity; D006874:Hydrostatic Pressure; D044085:Microfluidics; D009154:Mutation; D012867:Skin / Q000378:metabolism
chemical_list: D003094:Collagen