scholarly journals THE ULTRASTRUCTURE OF Z DISKS FROM WHITE, INTERMEDIATE, AND RED FIBERS OF MAMMALIAN STRIATED MUSCLES

1973 ◽  
Vol 57 (2) ◽  
pp. 261-277 ◽  
Author(s):  
R. W. D. Rowe
Keyword(s):  
Fiber Types ◽  
Spatial Relationships ◽  
Striated Muscles ◽  
Disk Model ◽  
Mammalian Muscle ◽  
Physiological Differences ◽  
White Fiber

The Z disk ultrastructure of white, intermediate, and red fibers from mammalian muscle is examined. Three models are proposed that explain the differences between the three types of Z disk. The three models are all based on the same concept, i.e., looping filaments from both sides of the Z disk. The differences between the models are in terms of the spatial relationships of adjacent loops within the Z disk. In the white fiber Z disk model all the loops from one side of the Z disk are on the same plane. In intermediate fibers there are two planes of loops from both sides of the Z disk, whereas in red fibers there are three planes of loops from both sides. The implications of these three structures are discussed in relation to known physiological differences between the fiber types.

The superfast extraocular myosin (MYH13) is localized to the innervation zone in both the global and orbital layers of rabbit extraocular muscle

2002 ◽  
Vol 205 (20) ◽  
pp. 3133-3142 ◽  
Author(s):  
Margaret M. Briggs ◽  
Fred Schachat
Keyword(s):  
Eye Movements ◽  
Striated Muscle ◽  
Contractile Activity ◽  
Regional Distribution ◽  
Motor Units ◽  
Molecular Heterogeneity ◽  
Ocular Motility ◽  
Fiber Types ◽  
Striated Muscles ◽  
Innervation Zone

SUMMARY Extraocular muscles (EOMs) are the most molecularly heterogeneous and physiologically diverse mammalian striated muscles. They express the entire array of striated muscle myosins, including a specialized myosin heavy chain MYH13, which is restricted to extraocular and laryngeal muscles. EOMs also exhibit a breadth of contractile activity, from superfast saccades to slow tracking and convergence movements. These movements are accomplished by the action of six ultrastructurally defined fiber types that differ from the type IIa, IIb, IIx and I fibers found in other skeletal muscles. Attempts to associate different eye movements with either the expression of different myosins or the activity of particular EOM fiber types are complicated by the molecular heterogeneity of several of the fiber types, and by electromyography studies showing that the majority of extraocular motor units participate in both fast and slow eye movements. To better understand the role of MYH13 in ocular motility, we generated MYH13-sequence-specific antibodies and used SDS-PAGE to quantify the regional distribution of myosin in EOM and to characterize its heterogeneity in single fibers. These studies demonstrate that MYH13 is preferentially expressed in the majority of orbital and global fibers in the central innervation zone of rabbit EOM. Many individual fibers express MYH13 with the fast IIb myosin and varying amounts of IIx myosin. The differential localization of MYH13, coupled with specialization of the sarcoplasmic reticulum and thin filament systems, probably explains how activation of the endplate band region enables the majority of EOM fibers to contribute to superfast contractions.

scholarly journals Mammalian Muscle Fiber Types and Their Adaptability

1978 ◽  
Vol 18 (1) ◽  
pp. 113-125 ◽  
Author(s):  
V. REGGIE EDGERTON
Keyword(s):  
Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Mammalian Muscle

The Molecular Diversity of Mammalian Muscle Fibers

Physiology ◽  
1993 ◽  
Vol 8 (4) ◽  
pp. 153-157 ◽  
Author(s):  
D Pette ◽  
RS Staron
Keyword(s):  
Molecular Diversity ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Fiber Types ◽  
Mammalian Muscle ◽  
Neural Input ◽  
Multiple Protein ◽  
Isoform Expression ◽  
Dynamic Structures

Although muscle fibers can be separated into major groups, a spectrum of fiber types exists due to the expression of multiple protein isoforms. Also, muscle fibers are dynamic structures with the ability to change isoform expression in response to altered functional demands, changes in neural input, or hormonal signals.

Fiber-type differences in muscle mitochondrial profiles

2003 ◽  
Vol 285 (4) ◽  
pp. R817-R826 ◽  
Author(s):  
S. C. Leary ◽  
C. N. Lyons ◽  
A. G. Rosenberger ◽  
J. S. Ballantyne ◽  
J. Stillman ◽  
...  
Keyword(s):  
Oxidative Phosphorylation ◽  
Fiber Type ◽  
Mitochondrial Protein ◽  
Krebs Cycle ◽  
Fiber Types ◽  
Striated Muscles ◽  
Qualitative Properties ◽  
Mitochondrial Content ◽  
Structural And Functional Properties ◽  
Myonuclear Domain

Although striated muscles differ in mitochondrial content, the extent of fiber-type specific mitochondrial specializations is not well known. To address this issue, we compared mitochondrial structural and functional properties in red muscle (RM), white muscle (WM), and cardiac muscle of rainbow trout. Overall preservation of the basic relationships between oxidative phosphorylation complexes among fiber types was confirmed by kinetic analyses, immunoblotting of native holoproteins, and spectroscopic measurements of cytochrome content. Fiber-type differences in mitochondrial properties were apparent when parameters were expressed per milligram mitochondrial protein. However, the differences diminished when expressed relative to cytochrome oxidase (COX), possibly a more meaningful denominator than mitochondrial protein. Expressed relative to COX, there were no differences in oxidative phosphorylation enzyme activities, pyruvate-based respiratory rates, H2O2 production, or state 4 proton leak respiration. These data suggest most mitochondrial qualitative properties are conserved across fiber types. However, there remained modest differences (∼50%) in stoichiometries of selected enzymes of the Krebs cycle, β-oxidation, and antioxidant enzymes. There were clear differences in membrane fluidity (RM > cardiac, WM) and proton conductance (H+/min/mV/U COX: WM > RM > cardiac). The pronounced differences in mitochondrial content between fiber types could be attributed to a combination of differences in myonuclear domain and modest effects on the expression of nuclear- and mitochondrially encoded respiratory genes. Collectively, these studies suggest constitutive pathways that transcend fiber types are primarily responsible for determining most quantitative and qualitative properties of mitochondria.

scholarly journals THE ULTRASTRUCTURE OF THE NEUROMUSCULAR JUNCTIONS OF MAMMALIAN RED, WHITE, AND INTERMEDIATE SKELETAL MUSCLE FIBERS

1970 ◽  
Vol 46 (1) ◽  
pp. 27-41 ◽  
Author(s):  
Helen A. Padykula ◽  
Geraldine F. Gauthier
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Neuromuscular Junctions ◽  
Fiber Diameter ◽  
Fiber Types ◽  
Rat Diaphragm ◽  
Mitochondrial Content ◽  
Albino Rat ◽  
Contact Points ◽  
White Fiber

Distinct ultrastructural differences exist at the neuromuscular junctions of red, white, and intermediate fibers of a mammalian twitch skeletal muscle (albino rat diaphragm). The primary criteria for recognizing the three fiber types are differences in fiber diameter, mitochondrial content, and width of the Z line. In the red fiber the neuromuscular relationship presents the least sarcoplasmic and axoplasmic surface at each contact. Points of contact are relatively discrete and separate, and axonal terminals are small and elliptical. The junctional folds are relatively shallow, sparse, and irregular in arrangement. Axoplasmic vesicles are moderate in number, and sarcoplasmic vesicles are sparse. In the white fiber long, flat axonal terminals present considerable axoplasmic surface. Vast sarcoplasmic surface area is created by long, branching, closely spaced junctional folds that may merge with folds at adjacent contacts to occupy a more continuous and widespread area. Axoplasmic and sarcoplasmic vesicles are numerous. Both axoplasmic and sarcoplasmic mitochondria of the white fiber usually contain intramitochondrial granules. The intermediate fiber has large axonal terminals that are associated with the most widely spaced and deepest junctional folds. In all three fiber types, the junctional sarcoplasm is rich in free ribosomes, cisternae of granular endoplasmic reticulum, and randomly distributed microtubules.

Characteristics of Skeletal Muscle Fiber Types in the Miniature Pig and the Effect of Training

1973 ◽  
Vol 51 (11) ◽  
pp. 825-831 ◽  
Author(s):  
R. H. Fitts ◽  
F. J. Nagle ◽  
R. G. Cassens
Keyword(s):  
Skeletal Muscle ◽  
Enzyme Histochemistry ◽  
Fiber Type ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Miniature Pig ◽  
Fast Red ◽  
Fiber Type Distribution ◽  
White Fiber

The fiber types present in miniature pig skeletal muscle were determined with enzyme histochemical techniques. Three distinct fiber types were found: a fast white fiber, a fast intermediate fiber, and a slow red fiber. The fiber types found in miniature pig (large mammal) skeletal muscle were different from those in rat (rodent) skeletal muscle where the fiber types are classified as fast white, slow intermediate, and fast red. The fiber type distribution in miniature pig skeletal muscle was not altered by either an endurance or sprint running program, despite physiologically measurable training effects. It is concluded that enzyme histochemistry is a good qualitative tool for assessing the fiber types present in a muscle but lacks the sensitivity to measure or quantitate changes due to training.

scholarly journals Fiber type-specific distribution of M-band proteins in chicken muscle.

1989 ◽  
Vol 37 (4) ◽  
pp. 447-454 ◽  
Author(s):  
B K Grove ◽  
L Cerny ◽  
J C Perriard ◽  
H M Eppenberger ◽  
L E Thornell
Keyword(s):  
Molecular Weight ◽  
Fiber Type ◽  
Sandwich Elisa ◽  
Motor Units ◽  
M Protein ◽  
Fiber Types ◽  
Type Ii ◽  
Striated Muscles ◽  
Specific Distribution ◽  
Type Ii Fibers

The functions of two myofibrillar proteins, myomesin (Mr 185,000) and M-protein (Mr 165,000), associated with the M-band are as yet unknown. To extend our knowledge of these proteins, we have examined chicken striated muscles with fast and slow contractile properties, e.g., pectoralis major, PLD, ALD, medial adductor, and lateral adductor, to determine the expression and isoform composition of myomesin and M-protein in various muscles and fiber types. The high molecular weight M-band proteins were characterized and quantitated using monoclonal antibodies in immunoblotting and double-antibody sandwich ELISA. Fiber specificity was determined by immuno- and enzyme histochemistry. In addition to the previously reported Mr 195,000 and 190,000 isoforms of myomesin in heart [Grove et al. (1985): J Cell Biol 101:1431], the Mr 185,000 myomesin in skeletal muscles may represent different isoforms in fast and slow muscles on the basis of distinctive degradation patterns. M-protein has the same molecular weight in striated chicken muscles and degradation patterns indicate only one isoform. The low quantities of M-protein in slow muscles were shown to be due to the absence of M-protein in two of the generally recognized slow fiber types, types I and III. Thus, M-protein was present only in fast type II fibers, whereas myomesin was ubiquitous in all fiber types. Whatever the causal relationship, M-protein appears to function in fast motor units composed of type II fibers.

Structural Organization and Distribution of Fiber Types in Extraocular Muscles of Cats

1972 ◽  
Vol 30 ◽  
pp. 34-35
Author(s):  
Asish C. Nag ◽  
Lee D. Peachey
Keyword(s):  
Fiber Type ◽  
Light And Electron Microscopy ◽  
Small Diameter ◽  
Extraocular Muscles ◽  
Fiber Types ◽  
Distinctive Features ◽  
Superior Rectus ◽  
Adult Cats ◽  
Different Diameters ◽  
Orbital Region

Cat extraocular muscles consist of two regions: orbital, and global. The orbital region contains predominantly small diameter fibers, while the global region contains a variety of fibers of different diameters. The differences in ultrastructural features among these muscle fibers indicate that the extraocular muscles of cats contain at least five structurally distinguishable types of fibers.Superior rectus muscles were studied by light and electron microscopy, mapping the distribution of each fiber type with its distinctive features. A mixture of 4% paraformaldehyde and 4% glutaraldehyde was perfused through the carotid arteries of anesthetized adult cats and applied locally to exposed superior rectus muscles during the perfusion.

Distribution of c-protein isoforms in sarcomeres of developing chick skeletal muscle

1988 ◽  
Vol 46 ◽  
pp. 226-227
Author(s):  
D. A. Fischman ◽  
J. E. Dennis ◽  
T. Obinata ◽  
H. Takano-Ohmuro
Keyword(s):  
Skeletal Muscles ◽  
Thick Filament ◽  
Protein Isoforms ◽  
Actin Binding ◽  
Striated Muscles ◽  
C Protein ◽  
Sarcomeric Protein ◽  
Thick Filaments ◽  
Cross Bridges ◽  
Bridge Bearing

C-protein is a 150 kDa protein found within the A bands of all vertebrate cross-striated muscles. By immunoelectron microscopy, it has been demonstrated that C-protein is distributed along a series of 7-9 transverse stripes in the medial, cross-bridge bearing zone of each A band. This zone is now termed the C-zone of the sarcomere. Interest in this protein has been sparked by its striking distribution in the sarcomere: the transverse repeat between C-protein stripes is 43 nm, almost exactly 3 times the 14.3 nm axial repeat of myosin cross-bridges along the thick filaments. The precise packing of C-protein in the thick filament is still unknown. It is the only sarcomeric protein which binds to both myosin and actin, and the actin-binding is Ca-sensitive. In cardiac and slow, but not fast, skeletal muscles C-protein is phosphorylated. Amino acid composition suggests a protein of little or no αhelical content. Variant forms (isoforms) of C-protein have been identified in cardiac, slow and embryonic muscles.

Use of EDS mapping to characterize thermochemical stability of fibers in intermetallic matrix composites

1992 ◽  
Vol 50 (1) ◽  
pp. 160-161
Author(s):  
John R. Porter
Keyword(s):  
Spatial Information ◽  
Beam Current ◽  
Fiber Types ◽  
Ceramic Fibers ◽  
Dye Transfer ◽  
Science Center ◽  
Commercial Development ◽  
Nih Image ◽  
Intermetallic Matrix Composites ◽  
Thermochemical Stability

New ceramic fibers, currently in various stages of commercial development, have been consolidated in intermetallic matrices such as γ-TiAl and FeAl. Fiber types include SiC, TiB2 and polycrystalline and single crystal Al2O3. This work required the development of techniques to characterize the thermochemical stability of these fibers in different matrices.SEM/EDS elemental mapping was used for this work. To obtain qualitative compositional/spatial information, the best realistically achievable counting statistics were required. We established that 128 × 128 maps, acquired with a 20 KeV accelerating voltage, 3 sec. live time per pixel (total mapping time, 18 h) and with beam current adjusted to give 30% dead time, provided adequate image quality at a magnification of 800X. The maps were acquired, with backgrounds subtracted, using a Noran TN 5500 EDS system. The images and maps were transferred to a Macintosh and converted into TIFF files using either TIFF Maker, or TNtolMAGE, a Microsoft QuickBASIC program developed at the Science Center. From TIFF files, images and maps were opened in either NIH Image or Adobe Photoshop for processing and analysis and printed from Microsoft Powerpoint on a Kodak XL7700 dye transfer image printer.

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