title: Measurement with an elastimeter of the stiffness of epithelial vesicles from pupal moth eye.
abstract: We have measured the stiffness of the monolayered epithelium which underlies the integument of an insect. Hollow vesicles of this epithelium, the hypodermis, formed during culture in a medium containing ecdysone, from squares of eye crescent integument excised from the moth Manduca sexta. Spherical vesicles were deformed by suction using an elastimeter; a plot of pressure vs. deformation has a slope which indicates the stiffness. This method allows a direct determination of the stiffness in a small patch of hypodermis at various places along the organism's surface. Vesicles produced from a sequence of sites along an adhesion gradient might show a corresponding sequence of stiffnesses. However, any difference in stiffness between vesicles from dorsal vs. ventral eye crescent was obscured by a large scatter in values for stiffness. Variation in the wall thickness of vesicles, and use of a scaling method involving elastic spheres, may underlie this scatter. The mean (±SD) corrected stiffness for all trials was 5.59±2.79 dynes/cm2/μm deformation.
authors.affiliation: Department of Zoology, University of Texas, 78712, Austin, TX.
authors.forename: Jon Richard
authors.initials: JR
authors.lastname: Nuelle
authors.affiliation: , 208 20th St., 37916, Knoxville, TN.
authors.forename: David Michael
authors.initials: DM
authors.lastname: Melchers
authors.affiliation: Department of Anatomical Sciences, University of Illinois College of Medicine, 506 S. Mathews Avenue, 61801, Urbana, IL, USA.
authors.forename: Jay Edward
authors.initials: JE
authors.lastname: Mittenthal
keywords: Adhesion; Biomechanics; Elastimeter; Epithelium; Manduca