scholarly journals Isomyosins in human type 1 and type 2 skeletal muscle fibres

1981 ◽  
Vol 193 (1) ◽  
pp. 229-233 ◽  
Author(s):  
R B Fitzsimons ◽  
J F Y Hoh

Human myosin from different skeletal muscles was analysed in a non-denaturing gel system, and the isoenzyme composition correlated with the histochemical composition of the muscle. Two components (SM1 and SM2) were associated with type 1 (slow-twitch) fibres, and three (FM1, FM2 and FM3) with type 2 (fast-twitch) fibres. Light-chain analysis was performed in sodium dodecyl sulphate/polyacrylamide gels. There are three light chains (LCs1a, LCS1b and LCs2) in type 1 fibres, and three (LCf1, LCf2 and LCf3) in type 2 fibres. LCf1 and LCs1b co-migrate in sodium dodecyl sulphate gels. The ratio of LCf3/LCf2 is correlated with the distribution of the individual fast isoenzymes. These results explain apparent discrepancies in the literature concerning the light-chain distribution of human myosin.

1996 ◽  
Vol 21 (6) ◽  
pp. 753-757 ◽  
Author(s):  
L. E. NECKING ◽  
R. LUNDSTRÖM ◽  
L. B. DAHLIN ◽  
G. LUNDBORG ◽  
L-E. THORNELL ◽  
...  

The early skeletal muscle response to vibration stimulus at two different displacement levels was examined. Twelve rats were anaesthetized and the hind limb was exposed to vibration, 80 Hz, 63 μm rms (root mean square) (group 1) and 40 Hz; 130 μm rms (group 2) for 5 hours/day for 2 days. Cross-sectional areas of vibrated muscle fibres were significantly larger in group 2. Sizes of different fibre types were differently affected: the slow-twitch type 1 fibres were significantly enlarged in both groups, while the fast-twitch type 2 fibres demonstrated a mixed response pattern. Centrally positioned muscle fibre nuclei increased significantly after vibration in group 2. It is concluded that the level of tissue displacement is a crucial factor for development of vibration-induced muscle injury.


1984 ◽  
Vol 222 (1228) ◽  
pp. 401-408 ◽  

An analysis has been performed of the native myosin isoenzyme com position of isolated skeletal muscle fibres from Xenopus laevis with welldefined isotonic contraction properties. Fast twitch ‘ white ’ (type 1) fibres contained three isomyosins; fast twitch ‘red ’ (type 2) fibres showed two major myosin bands with migration velocities very similar to those of the two slower bands in type 1. Slow twitch (type 3) fibres yielded a single, slowly migrating band as did slow tonic (type 5) fibres, whereas the myosin from type 4 (very slow twitch, ‘intermediate’) fibres migrated with a somewhat higher mobility. The results suggest that amphibian skeletal muscle may possess the principal fibre types found in mammals and birds.


2004 ◽  
Vol 121 (2) ◽  
pp. 101-107 ◽  
Author(s):  
Hans A. Keizer ◽  
Gert Schaart ◽  
Narenda N. Tandon ◽  
Jan F. C. Glatz ◽  
Joost J. F. P. Luiken

2021 ◽  
Author(s):  
Leonit Kiriaev ◽  
Peter J. Houweling ◽  
Kathryn N. North ◽  
Stewart I. Head

ABSTRACTThe common null polymorphism (R577X) in the ACTN3 gene is present in over 1.5 billion people worldwide and results in the absence of the protein α-actinin-3 from the Z-discs of fast-twitch skeletal muscle fibres. We have previously reported that this polymorphism is a modifier of dystrophin deficient Duchenne Muscular Dystrophy. To investigate the mechanism underlying this we use a double knockout (dk)Actn3KO/mdx (dKO) mouse model which lacks both dystrophin and sarcomere α-actinin-3. We used dKO mice and mdx dystrophic mice at 12 months (aged) to investigate the correlation between morphological changes to the fast-twitch dKO EDL and the reduction in force deficit produced by an in vitro eccentric contraction protocol. In the aged dKO mouse we found a marked reduction in fibre branching complexity that correlated with protection from eccentric contraction induced force deficit. Complex branches in the aged dKO EDL fibres (28%) were substantially reduced compared to aged mdx EDL fibres (68%) and this correlates with a graded force loss over three eccentric contractions for dKO muscles (∼35% after first contraction, ∼66% overall) compared to an abrupt drop in mdx upon the first eccentric contraction (∼73% after first contraction, ∼89% after three contractions). In dKO protection from eccentric contraction damage was linked with a doubling of SERCA1 pump density the EDL. We propose that the increased oxidative metabolism of fast-twitch glycolytic fibres characteristic of the null polymorphism (R577X) and increase in SR Ca2+ pump proteins reduces muscle fibre branching and decreases susceptibility to eccentric injury in the dystrophinopathies.


2012 ◽  
Author(s):  
Karla Punkt ◽  
Katharina Kandt ◽  
Andreas Oberbach ◽  
Volker Adams ◽  
Igor Buchwalow ◽  
...  

Author(s):  
Benjamin Assad Jaghutriz ◽  
Robert Wagner ◽  
Stephanie Kullmann ◽  
Louise Fritsche ◽  
Sabine S. Eckstein ◽  
...  

AbstractPrevalence of both type 1 and type 2 diabetes mellitus is growing worldwide and one major cause for morbidity and mortality. However, not every patient develops diabetes-related complications, but causes for the individual susceptibility are still not fully understood. As a platform to address this, we initiated the TUDID (TUebingen DIabetes Database) study, a prospective, monocentric, observational study that includes adults with diabetes mellitus who are treated in the inpatient clinic of a University Hospital in southern Germany. Besides a thorough clinical examination and extensive laboratory tests (with integrated biobanking), major study focuses are the kidneys, the eyes, the vasculature as well as cognition and mood where standardized investigations for early stages for diabetes complications are performed. Analyses of the data generated by this precise characterization of diabetes-related complications will contribute to our understanding of the development and course of such complications, and thus facilitate the implementation of tailored treatment options that can reduce the risk and severity of diabetes-related complications.


1987 ◽  
Vol 252 (6) ◽  
pp. C630-C639 ◽  
Author(s):  
J. L. Ivy ◽  
M. M. Chi ◽  
C. S. Hintz ◽  
W. M. Sherman ◽  
R. P. Hellendall ◽  
...  

Muscle biopsies were obtained from vastus lateralis muscles of four volunteers exercising at increasing work rates on a bicycle ergometer. Samples were taken at rest (t1), after a work load 23% below the blood lactate threshold (t2), 23% above this threshold (t3), and at exhaustion (t4). Individual muscle fibers were typed by their lactate dehydrogenase and adenylokinase levels and assayed for lactate, glucose-6-phosphate, and malate, (which preliminary data indicated to be the most responsive to increased activity) as well as ATP and phosphocreatine. The results in three of the four cases indicated that by the time of the t2 sample, almost all fibers, regardless of type, had been recruited. Additionally, there were no major differences in lactate concentration between type 1 and 2 fibers from muscle samples taken at t1, t2, and t3. It is concluded that in a muscle with fast-twitch glycolytic and slow-twitch oxidative fibers, all fibers share in the contraction to a substantial degree, even at moderate work loads, and that both the type 1 and 2 fibers contribute significantly to the initial rise in blood lactate during a graded exercise task. Metabolite responses in type 2 fibers differed in certain respects among the four participants. This is attributed to differences in their training backgrounds and consequent differences in type 2 fiber oxidative enzyme levels.


1989 ◽  
Vol 10 (3) ◽  
pp. 197-205 ◽  
Author(s):  
Stefano Schiaffino ◽  
Luisa Gorza ◽  
Saverio Sartore ◽  
Leopoldo Saggin ◽  
Simonetta Ausoni ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document