|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 200, Issue 10 1473-1482, Copyright © 1997 by Company of Biologists
JOURNAL ARTICLES |
G Fitzhugh and J Marden
Maximum lift production and the thermal sensitivity of lift production increase dramatically during adult maturation of Libellula pulchella dragonflies. Here, we report that the mechanistic basis for this transition appears to involve a developmental change in protein expression, which alters the Ca2+-sensitivity of muscle activation and twitch contraction kinetics. The alternatively spliced Ca2+ regulatory protein troponin T (TnT) undergoes an isoform shift during adult maturation. Skinned (demembranated) fibers of mature flight muscle are up to 13 times more sensitive to activation by Ca2+ than skinned fibers from teneral (newly emerged adult) flight muscle, and their Ca2+-sensitivity is more strongly affected by temperature. Intact muscle from mature individuals has a shorter time to peak tension and longer time to half-relaxation during twitch contractions, which is consistent with a greater Ca2+-sensitivity of mature muscle. Because it becomes activated more quickly and relaxes more slowly, mature flight muscle is able to generate, with each twitch, more force per unit area than teneral muscle; this difference in force becomes greater at high temperatures. There do not appear to be any age-related differences in actomyosin crossbridge properties, since teneral and mature flight muscles do not differ in shortening velocity, tetanic tension or instantaneous power output during isotonic contraction. Thus, variation in TnT expression appears to affect the temperature-dependent Ca2+-sensitivity of muscle activation, which in turn affects the kinetics and force production of the twitch contractions used by dragonflies during flight. This cascade of effects suggests that maturational changes in the expression of TnT isoforms may be a key determinant of overall muscle and organismal performance.
This article has been cited by other articles:
|
|
 |
|
  R. J. Schilder and J. H. Marden Parasites, proteomics and performance: effects of gregarine gut parasites on dragonfly flight muscle composition and function J. Exp. Biol., December 15, 2007; 210(24): 4298 - 4306. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M.-P. Schippers, R. Dukas, R. W. Smith, J. Wang, K. Smolen, and G. B. McClelland Lifetime performance in foraging honeybees: behaviour and physiology J. Exp. Biol., October 1, 2006; 209(19): 3828 - 3836. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. T. Thompson and W. M. Kier Ontogeny of mantle musculature and implications for jet locomotion in oval squid Sepioteuthis lessoniana J. Exp. Biol., February 1, 2006; 209(3): 433 - 443. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. P. Roberts and M. M. Elekonich Muscle biochemistry and the ontogeny of flight capacity during behavioral development in the honey bee, Apis mellifera J. Exp. Biol., November 15, 2005; 208(22): 4193 - 4198. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Herranz, J. Mateos, J. A. Mas, E. Garcia-Zaragoza, M. Cervera, and R. Marco The Coevolution of Insect Muscle TpnT and TpnI Gene Isoforms Mol. Biol. Evol., November 1, 2005; 22(11): 2231 - 2242. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. L. Hooper and J. B. Thuma Invertebrate Muscles: Muscle Specific Genes and Proteins Physiol Rev, July 1, 2005; 85(3): 1001 - 1060. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. J. Coughlin, N. D. Caputo, K. L. Bohnert, and F. E. Weaver Troponin T expression in trout red muscle correlates with muscle activation J. Exp. Biol., January 15, 2005; 208(2): 409 - 417. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Medler, T. Lilley, and D. L. Mykles Fiber polymorphism in skeletal muscles of the American lobster, Homarus americanus: continuum between slow-twitch (S1) and slow-tonic (S2) fibers J. Exp. Biol., July 15, 2004; 207(16): 2755 - 2767. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Medler Comparative trends in shortening velocity and force production in skeletal muscles Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2002; 283(2): R368 - R378. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. H. Marden and L. R. Allen Molecules, muscles, and machines: Universal performance characteristics of motors PNAS, April 2, 2002; 99(7): 4161 - 4166. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. J. Coughlin A Molecular Mechanism for Variations in Muscle Function in Rainbow Trout Integr. Comp. Biol., April 1, 2002; 42(2): 190 - 198. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. H. Marden, G. H. Fitzhugh, M. Girgenrath, M. R. Wolf, and S. Girgenrath Alternative splicing, muscle contraction and intraspecific variation: associations between troponin T transcripts, Ca2+ sensitivity and the force and power output of dragonfly flight muscles during oscillatory contraction J. Exp. Biol., March 12, 2002; 204(20): 3457 - 3470. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. H. Marden, G. H. Fitzhugh, M. R. Wolf, K. D. Arnold, and B. Rowan From the Cover: Alternative splicing, muscle calcium sensitivity, and the modulation of dragonfly flight performance PNAS, December 21, 1999; 96(26): 15304 - 15309. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. H. Marden and L. R. Allen Molecules, muscles, and machines: Universal performance characteristics of motors PNAS, April 2, 2002; 99(7): 4161 - 4166. [Abstract] [Full Text] [PDF]
|
|
