QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ball, D. Articles by Johnston, I. Search for Related Content PubMed PubMed Citation Articles by Ball, D. Articles by Johnston, I.

Journal of Experimental Biology, Vol 199, Issue 6 1363-1373, Copyright © 1996 by Company of Biologists

JOURNAL ARTICLES

Molecular mechanisms underlying the plasticity of muscle contractile properties with temperature acclimation in the marine fish Myoxocephalus scorpius

D Ball and I Johnston

Single fibres were isolated from the fast myotomal muscle of the short-horned sculpin (Myoxocephalus scorpius L.). Fish were acclimated to either 5 °C (10 h:14 h light:dark) or 15 °C (12 h:12 h light:dark) for 1­2 months. Isometric tension (Fmax) and unloaded contraction velocity (Vslack) were determined in maximally activated skinned fibres over the range 0 to 20 °C. Fibres isolated from 5 °C-acclimated and 15 °C-acclimated fish failed to relax completely following activations at 15 °C and 20 °C respectively. In 5 °C-acclimated fish, Fmax increased from 75 kN m-2 at 0 °C to 123 kN m-2 at 10 °C and was not significantly higher at 15 or 20 °C. The relationship between Fmax and temperature was not significantly different for cold- and warm-acclimated fish. Vslack was around 2.8 fibre lengths s-1 in both acclimation groups at 0 °C, but it increased at a significantly faster rate with temperature in 15 °C- than in 5 °C-acclimated fish. At 20 °C, Vmax was significantly higher in 15 °C-acclimated (8.7 fibre lengths s-1) than in 5 °C-acclimated fish (5.3 fibre lengths s-1). In order to investigate the molecular mechanism(s) underlying changes in Vmax, myosin was purified by ion-exchange chromatography. No difference in myosin heavy chain composition could be detected on the basis of peptide mapping with four different proteolytic enzymes. Two-dimensional polyacrylamide gel electrophoresis revealed no myofibrillar protein isoforms unique to either acclimation temperature. However, the ratio of myosin alkali light chain contents (LC3f:LC1f), as determined by capillary electrophoresis, was significantly lower in muscle from 15 °C-acclimated (0.73) than from 5 °C-acclimated fish (1.66). The results suggest that changes in Vmax are achieved via altered expression of myosin light chains independently of myosin heavy chain composition. In support of this hypothesis, the myofibrillar ATPase activity of fast muscle was not altered by temperature acclimation.

This article has been cited by other articles:

				F. Seebacher and R. S. James Plasticity of muscle function in a thermoregulating ectotherm (Crocodylus porosus): biomechanics and metabolism Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R1024 - R1032. [Abstract] [Full Text] [PDF]

				I. A. Johnston and G. K. Temple Thermal plasticity of skeletal muscle phenotype in ectothermic vertebrates and its significance for locomotory behaviour J. Exp. Biol., August 1, 2002; 205(15): 2305 - 2322. [Abstract] [Full Text] [PDF]

				J. M. Wakeling, N. J. Cole, K. M. Kemp, and I. A. Johnston The biomechanics and evolutionary significance of thermal acclimation in the common carp Cyprinus carpio Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2000; 279(2): R657 - R665. [Abstract] [Full Text] [PDF]

				T. Pearson, D. Hyde, and K. Bowler Heterologous acclimation: a novel approach to the study of thermal acclimation in the crab Cancer pagurus Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1999; 277(1): R24 - R30. [Abstract] [Full Text] [PDF]