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Holt NC. Beyond bouncy gaits: The role of multiscale compliance in skeletal muscle performance. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2019; 333:50-59. [DOI: 10.1002/jez.2261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 01/15/2019] [Accepted: 03/05/2019] [Indexed: 01/21/2023]
Affiliation(s)
- Natalie C. Holt
- Department of Biological Sciences; Northern Arizona University; Flagstaff Arizona
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2
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A high rigor temperature, not sarcomere length, determines light scattering properties and muscle colour in beef M. sternomandibularis meat and muscle fibres. Meat Sci 2018; 145:1-8. [DOI: 10.1016/j.meatsci.2018.05.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 01/23/2023]
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3
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Williams CD, Holt NC. Spatial Scale and Structural Heterogeneity in Skeletal Muscle Performance. Integr Comp Biol 2018; 58:163-173. [DOI: 10.1093/icb/icy057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- C D Williams
- Allen Institute for Cell Science, 615 Westlake Ave N, Seattle, WA 98109, USA
| | - N C Holt
- Department of Biology, Northern Arizona University, S. San Francisco Street, Flagstaff, AZ 86011, USA
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4
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Herzog W. Mechanisms of enhanced force production in lengthening (eccentric) muscle contractions. J Appl Physiol (1985) 2014; 116:1407-17. [DOI: 10.1152/japplphysiol.00069.2013] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In contrast to isometric and shortening contractions, many observations made on actively lengthening muscles cannot be readily explained with the sliding filament and cross-bridge theory. Specifically, residual force enhancement, the persistent increase in force following active muscle lengthening, beyond what one would expect based on muscle length, has not been explained satisfactorily. Here, we summarize the experimental evidence on residual force enhancement, critically evaluate proposed mechanisms for the residual force enhancement, and propose a mechanism for residual force enhancement that explains all currently agreed upon experimental observations. The proposed mechanism is based on the engagement of the structural protein titin upon muscle activation and an increase in titin's resistance to active compared with passive stretching. This change in resistance from the passive to the active state is suggested to be based on 1) calcium binding by titin upon activation, 2) binding of titin to actin upon activation, and 3) as a consequence of titin-actin binding—a shift toward stiffer titin segments that are used in active compared with passive muscle elongation. Although there is some experimental evidence for the proposed mechanism, it must be stressed that much of the details proposed here remain unclear and should provide ample research opportunities for scientists in the future. Nevertheless, the proposed mechanism for residual force enhancement explains all basic findings in this area of research.
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Affiliation(s)
- Walter Herzog
- Faculty of Kinesiology, University of Calgary, Alberta, Canada
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5
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Mazumder N, Qiu J, Foreman MR, Romero CM, Hu CW, Tsai HR, Török P, Kao FJ. Polarization-resolved second harmonic generation microscopy with a four-channel Stokes-polarimeter. OPTICS EXPRESS 2012; 20:14090-14099. [PMID: 22714473 DOI: 10.1364/oe.20.014090] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We developed a four-channel photon counting based Stokes-polarimeter for spatial characterization of polarization effects in second harmonic generation (SHG). We have implemented a calibration technique allowing quantitative measurement of polarization parameters, such as the degree of polarization (DOP), degree of linear polarization (DOLP), degree of circular polarization (DOCP), as well as anisotropy from the acquired Stokes parameters. The technique is used as contrast mechanism to characterize the polarization properties from two potassium dihydrogen phosphate (KDP) micro-crystals and collagen type-I in SHG microscopy.
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Affiliation(s)
- Nirmal Mazumder
- Institute of Biophotonics, National Yang-Ming University, 155, Li-Nong St. Taipei 11221, Taiwan
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6
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Lim CC, Helmes MH, Sawyer DB, Jain M, Liao R. High-throughput assessment of calcium sensitivity in skinned cardiac myocytes. Am J Physiol Heart Circ Physiol 2001; 281:H969-74. [PMID: 11454604 DOI: 10.1152/ajpheart.2001.281.2.h969] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isolated permeabilized cardiac myocytes have been used in the study of myofilament calcium sensitivity through measurement of the isometric force-pCa curve. Determining this force-pCa relationship in skinned myocytes is relatively expensive and carries a high degree of variability. We therefore attempted to establish an alternative high-throughput method to measure calcium sensitivity in cardiac myocytes. With the use of commercially available software that allows for precise measurement of sarcomere spacing, we measured sarcomere length changes in unloaded skinned cardiac myocytes over a range of calcium concentrations. With the use of this technique, we were able to accurately detect acute increases or decreases in myofilament calcium sensitivity after exposure to 10 mM caffeine or 5 mM 2,3-butanedione monoxime, respectively. This technique allows for the simple and rapid determination of myofilament calcium sensitivity in cardiac myocytes in a reproducible and inexpensive manner and could be used for high-throughput screening of pharmacological agents and/or transgenic mouse models for changes in myofilament calcium sensitivity.
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Affiliation(s)
- C C Lim
- Whitaker Cardiovascular Institute and Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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7
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Hajjar M, Même W, Léoty C. Measurement of sarcomere length during fast contraction of muscle fibers by digital image analysis. J Biomech 1999; 32:737-42. [PMID: 10400363 DOI: 10.1016/s0021-9290(99)00035-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A low-cost, high-resolution (spatial and temporal) image analysis system was developed to measure sarcomere length (Sl) during fast twitch of isolated striated muscle fibers at different temperatures. Fiber images were examined during twitch with an imaging rate of 220 Hz. To increase temporal resolution beyond 220 Hz, consecutive temporally shifted image sequences (N sequences) were acquired. Individual or average Sl was directly measured from a horizontal profile without spatial-frequency assessment. Measurement precision (E) was determined and expressed as: E(%) = 100xPs/(IsxSl), where Ps is the pixel size and Is the involved sarcomere number. At 18 degrees C during isometric twitch, Sls were measured with 220 Hz temporal and 0.2% spatial resolutions. Sl shortened in the central region (0.21+/-0.12 microm) as tension developed, reaching a maximal shortening of 8.09 + 2.05% (at rest, Sl = 2.59+/-0.05 microm, n = 4) in 32.5+/-1.96 ms. At 30 degrees C, Sl variations were examined with 880 Hz temporal resolution, in which case maximal S1 shortening was reached in 15.74+/-1.99 ms, and then decreased to 5.19+/-1.97% (at rest, S1 = 2.6+/-0.06 microm). The twitch tension developed by the whole fiber was recorded and compared with sarcomere length behavior. Sarcomere length variations in the central region were representative of overall developed tensions at 18 and 30 degrees C.
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Affiliation(s)
- M Hajjar
- Laboratoire de Physiologie Générale, Faculté des Sciences et des Techniques, Nantes, France.
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8
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Slawnych MP, Morishita L, Bressler BH. Spectral analysis of muscle fiber images as a means of assessing sarcomere heterogeneity. Biophys J 1996; 70:38-47. [PMID: 8770185 PMCID: PMC1224907 DOI: 10.1016/s0006-3495(96)79578-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A new image-analysis-based method is described for assessing sarcomere heterogeneity in skinned rabbit psoas muscle fiber segments. This method consists of off-line, two-dimensional Fourier spectral analysis of video-taped muscle images. Local sarcomere length is assessed by partitioning the muscle images into half and quarter images spanning the original image and analyzing the associated spectra. The spectra are analyzed in two different ways, yielding two measures of sarcomere length. The first measure is obtained by calculating and inverting the centroid frequency of the first-order peak associated with each two-dimensional Fourier spectrum. The second measure is obtained in a similar manner, the only difference being that the two-dimensional spectra are first collapsed into one-dimensional line spectra by summing the pixels perpendicular to the fiber axis. Comparison of the two measures provides a measure of striation skewness that cannot be obtained by other image analysis based methods that determine sarcomere length by analyzing selected line luminance profiles.
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Affiliation(s)
- M P Slawnych
- Department of Anatomy, University of British Columbia, Vancouver, Canada.
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9
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Willems ME, Huijing PA. Heterogeneity of mean sarcomere length in different fibres: effects on length range of active force production in rat muscle. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1994; 68:489-96. [PMID: 7957140 DOI: 10.1007/bf00599518] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Isometric active length-force characteristics of rat semimembranosus lateralis muscles [rats, n = 6, body mass = 292 (SD 9) g] were recorded. Muscles were photographed during the force plateaus of the tetani to determine lengths of proximal, intermediate and distal fibres. From the mean number of sarcomeres in series in those fibres, mean sarcomere length at different muscle lengths was calculated. The heterogeneity of mean sarcomere lengths for each muscle was quantified according to the coefficient of variation of sarcomere lengths at muscle optimal length. Absolute muscle length changes were equal to fibre length changes. At all muscle lengths, mean sarcomere lengths in the distal fibres were significantly greater than those in proximal and intermediate fibres. The heterogeneity of mean sarcomere lengths augmented the length range of active force production between muscle optimal length and active slack length by about 38% to 43%. We concluded that in a muscle with a low degree of pennation, the heterogeneity of mean sarcomere lengths should be considered as a substantial contributor to the length range over which active force can be produced. In our experiment, the length ranges of active force production between optimal and slack length showed considerable differences (range 18.7-24.9 mm). The coefficient of correlation between length ranges and mean number of sarcomeres in series in various muscle regions was extremely low (r = -0.14) and not significant. The coefficient of correlation between length ranges and heterogeneity was high (r = 0.88) and significant. These data would suggest that muscles with a similar number of sarcomeres in series can exhibit quite different functional characteristics.
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Affiliation(s)
- M E Willems
- Vakgroep Functionele Anatomie, Faculteit der Bewegingswetenschappen, Vrije Universiteit Amsterdam, The Netherlands
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10
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Sosa H, Popp D, Ouyang G, Huxley HE. Ultrastructure of skeletal muscle fibers studied by a plunge quick freezing method: myofilament lengths. Biophys J 1994; 67:283-92. [PMID: 7918996 PMCID: PMC1225358 DOI: 10.1016/s0006-3495(94)80479-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have set up a system to rapidly freeze muscle fibers during contraction to investigate by electron microscopy the ultrastructure of active muscles. Glycerinated fiber bundles of rabbit psoas muscles were frozen in conditions of rigor, relaxation, isometric contraction, and active shortening. Freezing was carried out by plunging the bundles into liquid ethane. The frozen bundles were then freeze-substituted, plastic-embedded, and sectioned for electron microscopic observation. X-ray diffraction patterns of the embedded bundles and optical diffraction patterns of the micrographs resemble the x-ray diffraction patterns of unfixed muscles, showing the ability of the method to preserve the muscle ultrastructure. In the optical diffraction patterns layer lines up to 1/5.9 nm-1 were observed. Using this method we have investigated the myofilament lengths and concluded that there are no major changes in length in either the actin or the myosin filaments under any of the conditions explored.
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Affiliation(s)
- H Sosa
- Department of Biology, Brandeis University, Waltham, Massachusetts 02254
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11
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Trombitás K, Baatsen P, Schreuder J, Pollack GH. Contraction-induced movements of water in single fibres of frog skeletal muscle. J Muscle Res Cell Motil 1993; 14:573-84. [PMID: 8126217 DOI: 10.1007/bf00141554] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Although X-ray diffraction measurements imply almost constant filament separation during isometric contraction, such constancy does not hold at the level of the isolated cell; cell cross-section increases substantially during isometric contraction. This expansion could arise from accumulation of water drawn from other fibre regions, or from water drawn into the cell from outside. To distinguish between these hypotheses, we froze single fibres of frog skeletal muscle that were jacketed by a thin layer of water. Frozen fibres were freeze-substituted, sectioned transversely, and examined in the electron microscope. In fibres frozen during contraction, we found large amounts of water just beneath the sarcolemma, less in deeper regions, and almost none in the fibre core. Such gradients were absent or diminished in fibres frozen in the relaxed state. The water was not confined to the myofibril space alone; we found large water spaces between myofibrils, particularly near mitochondria. Accumulation of water between myofibrils and around mitochondria implies that the driving force for water movement probably lies outside the filament lattice, and may therefore be osmotic. The fact that the distribution was nonuniform-highest near the sarcolemma and lowest in the core--implies that the water was likely drawn from the thin jacket surrounding the cell. Thus, the contractile cycle appears to be associated with water entry into and exit from the cell.
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Affiliation(s)
- K Trombitás
- Center for Bioengineering, University of Washington, Seattle 98195
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12
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Giembycz MA, Raeburn D. Current concepts on mechanisms of force generation and maintenance in airways smooth muscle. PULMONARY PHARMACOLOGY 1992; 5:279-97. [PMID: 1477484 DOI: 10.1016/0952-0600(92)90071-n] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- M A Giembycz
- Department of Thoracic Medicine, Royal Brompton National Heart and Lung Institute, London, UK
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13
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Levine RJ, Woodhead JL, King HA. The effect of calcium activation of skinned fiber bundles on the structure of Limulus thick filaments. J Biophys Biochem Cytol 1991; 113:573-83. [PMID: 2016337 PMCID: PMC2288957 DOI: 10.1083/jcb.113.3.573] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Here we present evidence that strongly suggests that the well-documented phenomenon of A-band shortening in Limulus telson muscle is activation dependent and reflects fragmentation of thick filaments at their ends. Calcium activation of detergent-skinned fiber bundles of Limulus telson muscle results in large decreases in A-band (from 5.1 to 3.3 microns) and thick filament (from 4.1 to 3.3 microns) lengths and the release of filament end fragments. In activated fibers, maintained stretched beyond overlap of thick and thin filaments, these end fragments are translocated to varying depths within the I-bands. Here they are closely associated with fine filamentous structures that also span the gap between A- and I-bands and attach to the distal one-third of the thick filaments. End-fragments are rarely, if ever, present in similarly stretched and skinned, but unstimulated fibers, although fine "gap filaments" persist. Negatively stained thick filaments, separated from skinned, calcium-activated, fiber bundles, allowed to shorten freely, are significantly shorter than those obtained from unstimulated fibers, but are identical to the latter with respect to both the surface helical array of myosin heads and diameters. Many end-fragments are present on grids containing thick filaments from activated fibers; few, if any, on those from unstimulated fibers. SDS-PAGE shows no evidence of proteolysis due to activation and demonstrates the presence of polypeptides with very high molecular weights in the preparations. We suggest that thick filament shortening is a direct result of activation in Limulus telson muscle and that it occurs largely by breakage within a defined distal region of each polar half of the filament. It is possible that at least some of the fine "gap filaments" are composed of a titin-like protein. They may move the activation-produced, fragmented ends of thick filaments to which they attach, into the I-bands by elastic recoil, in highly stretched fibers.
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Affiliation(s)
- R J Levine
- Department of Anatomy and Neurobiology, Medical College of Pennsylvania, Philadelphia 19129
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14
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Niggli E, Lederer WJ. Restoring forces in cardiac myocytes. Insight from relaxations induced by photolysis of caged ATP. Biophys J 1991; 59:1123-35. [PMID: 1868157 PMCID: PMC1281347 DOI: 10.1016/s0006-3495(91)82327-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Concentration jumps of intracellular ATP were produced by photolysis of P3-1-(2-nitrophenyl)ethyl (NPE)-caged ATP and were used to investigate the passive relengthening properties in unloaded cardiac myocytes. Patch-clamp pipettes in the whole-cell mode were used to voltage-clamp the myocytes and to load the cells with caged ATP while optical methods were applied to record sarcomere length or cell length simultaneously. Cell length was varied using energy deprivation contractures while intracellular Ca2+ was controlled with EGTA. At sarcomere lengths between 1.8 and 1.4 microns cellular relengthening after photolysis of caged ATP was rapid (t1/2 approximately 100 ms) and could be well described by a simple mechanical model. However, ATP jumps made at sarcomere lengths approximately 1.1 microns led to slow relengthening (t1/2 approximately seconds), comparable to the slow reextensions observed in skinned myocytes after bulk solution changes. We attribute the slow and incomplete relengthening of intact and skinned myocytes after severe rigor shortening to deformation and alteration of structural elements inside the cell. Relengthening from intermediate sarcomere lengths in intact cells is elastic and provides information about the underlying relengthening forces inside the cell. The data do not support the presence of a significant discontinuity in elastic modulus at a sarcomere length of approximately 1.6 microns expected from ultrastructural features of the sarcomeres and from observations in skinned myocytes. Our results suggest that the cell length measurements usually performed in this preparation provide an adequate description of the force produced by the unloaded cell in the steady state. The results also provide a way to estimate the error arising from viscous forces during rapid shortening.
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Affiliation(s)
- E Niggli
- Department of Physiology, University of Maryland School of Medicine, Baltimore
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