scholarly journals The multiplicity of combinations of myosin light chains and heavy chains in histochemically typed single fibres. Rabbit tibialis anterior muscle

1987 ◽  
Vol 243 (3) ◽  
pp. 695-699 ◽  
Author(s):  
R S Staron ◽  
D Pette
Keyword(s):  
Tibialis Anterior ◽  
Tibialis Anterior Muscle ◽  
Single Fibre ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Type I ◽  
Slow Myosin ◽  
Heavy Chains ◽  
Fast Myosin ◽  
Fast Light

1. Combined histochemical and biochemical single-fibre analyses [Staron & Pette (1987) Biochem. J. 243, 687-693], were used to investigate the rabbit tibialis-anterior fibre population. 2. This muscle is composed of four histochemically defined fibre types (I, IIC, IIA and IIB). 3. Type I fibres contain slow myosin light chains LC1s and LC2 and the slow myosin heavy chain HCI, and types IIA and IIB contain the fast myosin light chains LC1f, LC2f and LC3f and the fast heavy chains HCIIa and HCIIb respectively. 4. A small fraction of fibres (IIAB), histochemically intermediate between types IIA and IIB, contain the fast light myosin chains but display a coexistence of HCIIa and HCIIb. 5. Similarly to the soleus muscle, C fibres in the tibialis anterior muscle contain both fast and slow myosin light chains and heavy chains. The IIC fibres show a predominance of the fast forms and the IC fibres (histochemically intermediate between types I and IIC) a predominance of the slow forms. 6. A total of 60 theoretical isomyosins can be derived from these findings on the distribution of fast and slow myosin light and heavy chains in the fibres of rabbit tibialis anterior muscle.

scholarly journals The multiplicity of combinations of myosin light chains and heavy chains in histochemically typed single fibres. Rabbit soleus muscle

1987 ◽  
Vol 243 (3) ◽  
pp. 687-693 ◽  
Author(s):  
R S Staron ◽  
D Pette
Keyword(s):  
Cross Sections ◽  
Slow Light ◽  
Troponin I ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Adult Rabbit ◽  
Type I ◽  
Slow Myosin ◽  
Heavy Chains ◽  
Freeze Dried

1. Six adult rabbit soleus muscles were analysed by isolating histochemically identified fibre pieces from freeze-dried serial cross-sections. 2. By the use of this method, four fibre types (I, IC, IIC and IIA) were identified and analysed micro-electrophoretically. 3. Type I fibres contained the slow myosin heavy chain HCI and the slow myosin light chains LC1s and LC2s. 4. Type IIA fibres contained the fast myosin HCIIa with the fast light chains and, in addition, either LC1s or both LC1s and LC2s. 5. The C fibres (IC and IIC) represented intermediate populations between types I and IIC (IC) and between IC and IIA (IIC). They contained varied ratios of HCI/HCIIa with both sets of fast and slow light chains. With regard to myosin composition and isoforms of other myofibrillar proteins (M- and C-proteins, alpha-tropomyosin, troponin I), IC fibres resembled type I and IIC fibres resembled type IIA. 6. The presence of various myosin light and heavy chains within a specific fibre suggests a multiplicity of isomyosins. Without consideration of LC1sa and LC1sb differences, at least 54 possible isomyosins can be derived: type I fibres contain one isomyosin, types IC and IIC 54 possible isomyosins, and type IIA up to 18.

scholarly journals Chronic denervation of rat hemidiaphragm: maintenance of fiber heterogeneity with associated increasing uniformity of myosin isoforms.

1985 ◽  
Vol 100 (1) ◽  
pp. 161-174 ◽  
Author(s):  
U Carraro ◽  
D Morale ◽  
I Mussini ◽  
S Lucke ◽  
M Cantini ◽  
...  
Keyword(s):  
Light And Electron Microscopy ◽  
Myosin Isoforms ◽  
Myosin Heavy Chains ◽  
Denervated Muscle ◽  
Slow Myosin ◽  
Heavy Chains ◽  
Fast Myosin ◽  
Long Time ◽  
Chronic Denervation

During several months of denervation, rat mixed muscles lose slow myosin, though with variability among animals. Immunocytochemical studies showed that all the denervated fibers of the hemidiaphragm reacted with anti-fast myosin, while many reacted with anti-slow myosin as well. This has left open the question as to whether multiple forms of myosin co-exist within individual fibers or a unique, possibly embryonic, myosin is present, which shares epitopes with fast and slow myosins. Furthermore, one can ask if the reappearance of embryonic myosin in chronically denervated muscle is related both to its re-expression in the pre-existing fibers and to cell regeneration. To answer these questions we studied the myosin heavy chains from individual fibers of the denervated hemidiaphragm by SDS PAGE and morphologically searched for regenerative events in the long term denervated muscle. 3 mo after denervation the severely atrophic fibers of the hemidiaphragm showed either fast or a mixture of fast and slow myosin heavy chains. Structural analysis of proteins sequentially extracted from muscle cryostat sections showed that slow myosin was still present 16 mo after denervation, in spite of the loss of the selective distribution of fast and slow features. Therefore muscle fibers can express adult fast myosin not only when denervated during their differentiation but also after the slow program has been expressed for a long time. Light and electron microscopy showed that the long-term denervated muscle maintained a steady-state atrophy for the rat's life span. Some of the morphological features indicate that aneural regeneration events continuously occur and significantly contribute to the increasing uniformity of the myosin gene expression in long-term denervated diaphragm.

scholarly journals Electrophoretic analysis of proteins from single bovine muscle fibres

1981 ◽  
Vol 195 (1) ◽  
pp. 317-327 ◽  
Author(s):  
O A Young ◽  
C L Davey
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Fibre Types ◽  
Type I ◽  
Slow Fibre ◽  
Slow Myosin ◽  
Fast Myosin ◽  
Fast Myosin Heavy Chain

A number of single fibres were isolated by dissection of four bovine masseter (ma) muscles, three rectus abdominis (ra) muscles and eight sternomandibularis (sm) muscles. By histochemical criteria these muscles contain respectively, solely slow fibres (often called type I), predominantly fast fibres (type II), and a mixture of fast and slow. The fibres were analysed by conventional sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and the gels stained with Coomassie Blue. Irrespective of the muscle, every fibre could be classed into one of two broad groups based on the mobility of proteins in the range 135000-170000 daltons. When zones containing myosin heavy chain were cut from the single-fibre gel tracks and ‘mapped’ [Cleveland, Fischer, Kirschner & Laemmli (1977) J. Biol. Chem. 252, 1102-1106] with Staphylococcus proteinase, it was found that one group always contained fast myosin heavy chain, whereas the second group always contained the slow form. Moreover, a relatively fast-migrating alpha-tropomyosin was associated with the fast myosin group and a slow-migrating form with the slow myosin group. All fibres also contained beta-tropomyosin; the coexistence of alpha- and beta-tropomyosin is at variance with evidence that alpha-tropomyosin is restricted to fast fibres [Dhoot & Perry (1979) Nature (London) 278, 714-718]. Fast fibres containing the expected fast light chains and troponins I and C fast were identified in the three ra muscles, but in only four sm muscles. In three other sm muscles, all the fast fibres contained two troponins I and an additional myosin light chain that was more typical of myosin light chain 1 slow. The remaining sm muscle contained a fast fibre type that was similar to the first type, except that its myosin light chain 1 was more typical of the slow polymorph. Troponin T was bimorphic in all fast fibres from a ra muscles and in at least some fast fibres from one sm muscle. Peptide ‘mapping’ revealed two forms of fast myosin heavy chain distributed among fast fibres. Each form was associated with certain other proteins. Slow myosin heavy chain was unvarying in three slow fibre types identified. Troponin I polymorphs were the principal indicator of slow fibre types. The myofibrillar polymorphs identified presumably contribute to contraction properties, but beyond cud chewing involving ma muscle, nothing is known of the conditions that gave rise to the variable fibre composites in sm and ra muscles.

scholarly journals Myosin isozymes in normal and cross-reinnervated cat skeletal muscle fibers.

1983 ◽  
Vol 97 (3) ◽  
pp. 756-771 ◽  
Author(s):  
G F Gauthier ◽  
R E Burke ◽  
S Lowey ◽  
A W Hobbs
Keyword(s):  
Skeletal Muscle ◽  
Atpase Activity ◽  
Muscle Fibers ◽  
Motor Units ◽  
Myosin Atpase ◽  
Light Chains ◽  
Slow Myosin ◽  
Fast Myosin ◽  
Physiological Properties ◽  
Contraction Times

Immunocytochemical characteristics of myosin have been demonstrated directly in normal and cross-reinnervated skeletal muscle fibers whose physiological properties have been defined. Fibers belonging to individual motor units were identified by the glycogen-depletion method, which permits correlation of cytochemical and physiological data on the same fibers. The normal flexor digitorum longus (FDL) of the cat is composed primarily of fast-twitch motor units having muscle fibers with high myosin ATPase activity. These fibers reacted with antibodies specific for the two light chains characteristic of fast myosin, but not with antibodies against slow myosin. Two categories of fast fibers, corresponding to two physiological motor unit types (FF and FR), differed in their immunochemical response, from which it can be concluded that their myosins are distinctive. The soleus (SOL) consists almost entirely of slow-twitch motor units having muscle fibers with low myosin ATPase activity. These fibers reacted with antibodies against slow myosin, but not with antibodies specific for fast myosin. When the FDL muscle was cross-reinnervated by the SOL nerve, twitch contraction times were slowed about twofold, and motor units resembled SOL units in a number of physiological properties. The corresponding muscle fibers had low ATPase activity, and they reacted with antibodies against slow myosin only. The myosin of individual cross-reinnervated FDL muscle units was therefore transformed, apparently completely, to a slow type. In contrast, cross-reinnervation of the SOL muscle by FDL motoneurons did not effect a complete converse transformation. Although cross-reinnervated SOL motor units had faster than normal twitch contraction times (about twofold), other physiological properties characteristic of type S motor units were unchanged. Despite the change in contraction times, cross-reinnervated SOL muscle fibers exhibited no change in ATPase activity. They also continued to react with antibodies against slow myosin, but in contrast to the normal SOL, they now showed a positive response to an antibody specific for one of the light chains of fast myosin. The myosins of both fast and slow muscles were thus converted by cross-reinnervation, but in the SOL, the newly synthesized myosin was not equivalent to that normally present in either the FDL or SOL. This suggests that, in the SOL, alteration of the nerve supply and the associated dynamic activity pattern are not sufficient to completely respecify the type of myosin expressed.

Capillary supply of the tibialis anterior muscle in young, healthy, and moderately active men and women

2002 ◽  
Vol 92 (4) ◽  
pp. 1451-1457 ◽  
Author(s):  
M. M. Porter ◽  
S. Stuart ◽  
M. Boij ◽  
J. Lexell
Keyword(s):  
Gender Differences ◽  
Gender Difference ◽  
Tibialis Anterior ◽  
Fiber Type ◽  
Tibialis Anterior Muscle ◽  
Type I ◽  
Men And Women ◽  
Fiber Size ◽  
The Difference ◽  
Muscle Biopsies

Tibialis anterior muscle biopsies from moderately active men and women (21–30 yr; n= 30) were examined to determine potential gender differences in capillarization. The fiber type proportions [type I (T1) ∼73%] were unaffected by gender. The men (M) had significantly ( P < 0.001) larger fibers than the women (W), with a greater gender effect for type II (T2) fibers ( P < 0.001). The M and W had similar capillary densities (CD ∼390 capillaries/mm2), but the capillaries-to-fiber ratio (C/F) was higher in the M (M = 2.20 ± 0.35, W = 1.66 ± 0.32; P < 0.01). Capillary contacts (CC) were higher in T2 than T1 for the M ( P < 0.01), but not W, and M had greater CC ( P < 0.001). Both fiber area per capillary (FA/C) and fiber perimeter per capillary (FP/C) indicated that T1 fibers had greater capillarization than T2 fibers ( P < 0.001). There were no gender differences in T1 FA/C and T2 FA/C or T1 FP/C, but a gender difference existed for T2 FP/C (M = 60.5 ± 10.9, W = 70.6 ± 13.4; P < 0.01). The gender difference for C/F could be explained by fiber size; however, the physiological implications of the difference in T2 FP/C remains to be determined. In conclusion, despite gender differences for fiber size, overall, capillarization was similar between the men and women.

Comparison of the molecular, antigenic and ATPase determinants of fast myosin heavy chains in rat and human: a single-fibre study

1997 ◽  
Vol 435 (1) ◽  
pp. 151-163 ◽  
Author(s):  
J. A. A. Pereira Sant'Ana ◽  
Steven Ennion ◽  
Anthony J. Sargeant ◽  
Antoon F. M. Moorman ◽  
G. Goldspink
Keyword(s):  
Single Fibre ◽  
Myosin Heavy Chains ◽  
Heavy Chains ◽  
Fast Myosin

scholarly journals Fast myosin light chain expression in chicken muscles studied by in situ hybridization.

1992 ◽  
Vol 40 (10) ◽  
pp. 1547-1557 ◽  
Author(s):  
R Billeter ◽  
M Messerli ◽  
E Wey ◽  
A Puntschart ◽  
K Jostarndt ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Fiber Type ◽  
Light Chains ◽  
Myosin Light Chains ◽  
Two Dimensional ◽  
Fast Myosin ◽  
Chicken Muscles

We have studied the fiber type-specific expression of the fast myosin light chain isoforms LC 1f, LC 2f, and LC 3f in adult chicken muscles using in situ hybridization and two-dimensional gel electrophoresis. Type II (fast) fibers contain all three fast myosin light chain mRNAs; Types I and III (slow) fibers lack them. The myosin light chain patterns of two-dimensional gels from microdissected single fibers match their mRNA signals in the in situ hybridizations. The results confirm and extend previous studies on the fiber type-specific distribution of myosin light chains in chicken muscles which used specific antibodies. The quantitative ratios between protein and mRNA content were not the same for all three fast myosin light chains, however. In bulk muscle samples, as well as in single fibers, there was proportionally less LC 3f accumulated for a given mRNA concentration than LC 1f or LC 2f. Moreover, the ratio between LC 3f mRNA and protein was different in samples from muscles, indicating that LC 3f is regulated somewhat differently than LC 1f and LC 2f. In contrast to other in situ hybridization studies on the fiber type-specific localization of muscle protein mRNAs, which reported the RNAs to be located preferentially at the periphery of the fibers, we found all three fast myosin light chain mRNAs quite evenly distributed within the fiber's cross-sections, and also in the few rare fibers which showed hybridization signals several-fold higher than their surrounding counterparts. This could indicate principal differences in the intracellular localization among the mRNAs coding for various myofibrillar protein families.

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