Structural and osmotic studies of single giant fibres of barnacle muscle

Gayton, D. C.; Elliott, G.F.

doi:10.1007/bf00716023

Cited by 9 publications

(4 citation statements)

References 36 publications

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“…It develops tension when calcium activated, much as does skeletal muscle. Heart mus-telson muscle (45), and barnacle muscle (70), there are 12 thin filaments around each thick filament (a 6:1 ratio) cle differs from skeletal muscle, however, in the calcium level at which the equatorial intensities change. Calcium activation causes I 10 to drop and I 11 to rise at a pCa of Ç6, whereas force development requires a pCa of 0.5 higher.…”

Section: B Skinned Muscle Fibersmentioning

confidence: 99%

The Filament Lattice of Striated Muscle

Millman

1998

Physiological Reviews

221

239

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The filament lattice of striated muscle is an overlapping hexagonal array of thick and thin filaments within which muscle contraction takes place. Its structure can be studied by electron microscopy or X-ray diffraction. With the latter technique, structural changes can be monitored during contraction and other physiological conditions. The lattice of intact muscle fibers can change size through osmotic swelling or shrinking or by changing the sarcomere length of the muscle. Similarly, muscle fibers that have been chemically or mechanically skinned can be compressed with bathing solutions containing very large inert polymeric molecules. The effects of lattice change on muscle contraction in vertebrate skeletal and cardiac muscle and in invertebrate striated muscle are reviewed. The force developed, the speed of shortening, and stiffness are compared with structural changes occurring within the lattice. Radial forces between the filaments in the lattice, which can include electrostatic, Van der Waals, entropic, structural, and cross bridge, are assessed for their contributions to lattice stability and to the contraction process.

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Section: B Skinned Muscle Fibersmentioning

confidence: 99%

The Filament Lattice of Striated Muscle

Millman

1998

Physiological Reviews

221

239

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“…As can be seen, in the transverse section the thick filaments are packed hexagonally but not regularly as observed on amphibian striated muscle (Huxley, 1957), and the thin filaments clearly form "rings" around the thick filaments. Therefore, the removal of the sarcolemma by glycerol and the incubation in the relaxing solution do not affect the architecture of the contractile filaments observed on freshly isolated fibers (Gayton and Elliott, 1980;Clark et al, 1981), so that glycerinated fibers can be used to study the orientation of the myoplasm proteins.…”

Section: Electron Microscopy Of Glycerinated Fibersmentioning

confidence: 99%

Raman spectroscopy of cytoplasmic muscle fiber proteins. Orientational order

Pézolet¹,

Pigeon²,

Ménard³

et al. 1988

Biophysical Journal

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The polarized Raman spectra of glycerinated and intact single muscle fibers of the giant barnacle were obtained. These spectra show that the conformation-sensitive amide I, amide III, and C-C stretching vibrations give Raman bands that are stronger when the electric field of both the incident and scattered radiation is parallel to the fiber axis (Izz). The detailed analysis of the amide I band by curve fitting shows that approximately 50% of the alpha-helical segments of the contractile proteins are oriented along the fiber axis, which is in good agreement with the conformation and composition of muscle fiber proteins. Difference Raman spectroscopy was also used to highlight the Raman bands attributed to the oriented segments of the alpha-helical proteins. The difference spectrum, which is very similar to the spectrum of tropomyosin, displays amide I and amide III bands at 1,645 and 1,310 cm-1, respectively, the bandwidth of the amide I line being characteristic of a highly alpha-helical biopolymer with a small dispersion of dihedral angles. A small dichroic effect was also observed for the band due to the CH2 bending mode at 1,450 cm-1 and on the 1,340 cm-1 band. In the C-C stretching mode region, two bands were detected at 902 and 938 cm-1 and are both assigned to the alpha-helical conformation.

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“…Stimulation was set so that the maximum active force was always less than half of the maximum attainable level to prevent fiber damage owing to detachment from the cannula. Sarcomere lengths were not measured and they vary along the length of the fiber (Gayton and Elliott, 1980), so we cannot say precisely how much filament overlap there is and how much it changes as we increase or decrease muscle length. Muscle length was set to the value at which passive tension in the absence of the internal electrode is just detectable.…”

Section: The Length-force Relation and Extra Calciummentioning

confidence: 99%

Extra calcium on shortening in barnacle muscle. Is the decrease in calcium binding related to decreased cross-bridge attachment, force, or length?

Gordon

Ridgway

1987

The Journal of General Physiology

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Barnacle single muscle fibers were microinjected with the calcium-specific photoprotein aequorin. We have previously shown (Ridgway, E.B., and A. M. Gordon, 1984, Journal of General Physiology, 83:75-104) that when barnacle fibers are stimulated under voltage clamp and length control and allowed to shorten during the declining phase of the calcium transient, extra myoplasmic calcium is observed. The time course of the extra calcium for shortening steps at different times during the calcium transient is intermediate between those of free calcium and muscle force. Furthermore, the amplitude increases with an increased stimulus, calcium transient, and force. Therefore, the extra calcium probably comes from the activating sites on the myofilaments, possibly as a result of changes in calcium binding by the activating sites. The change in calcium binding may be due, in turn, to the change in muscle length and/or muscle force and/or cross-bridge attachment per se. In the present article, we show that the amount of the extra calcium depends on the initial muscle length, declining at shorter lengths. This suggests lengthdependent calcium binding. The relation between initial length and extra calcium, however, parallels that between initial length and peak active force. The ratio of extra calcium to active force is therefore virtually independent of initial length. These data do not distinguish between a direct effect of length on calcium binding and an indirect effect owing to changes in cross-bridge attachment and force through some geometrical factor. The amount of extra calcium increases with the size of the shortening step, tending toward saturation for steps of >_10%. This experiment suggests that calcium binding depends on muscle force or cross-bridge attachment, not just length (if at all). There is much less extra calcium seen with shortening steps at high force when the high force results from stretch of the active muscle than when it results from on May 11, 2018 jgp.rupress.org Downloaded from http://doi.org/10.1085/jgp.90.3.321 Published Online: 1 September, 1987 | Supp Info: 322THE JOURNAL OF GENERAL PHYSIOLOGY 9 VOLUME 90 9 1987 increased stimulation of muscle. Thus, the number of attached cross-bridges appears to be more important than force itself. After a conditioning step decrease in length, force redevelops. A second test shortening step during force redevelopment produces less extra calcium than is seen in the absence of the conditioning step. Delaying the test step until more force has redeveloped increases the extra calcium seen with the test step, the increase paralleling the force redevelopment. This implies that calcium binding is increased by crossbridge reattachment. These experiments do not exclude the existence of lengthdependent calcium binding, but strongly suggest that there is increased calcium binding to the activating sites when cross-bridges attach.

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Structural and osmotic studies of single giant fibres of barnacle muscle

Cited by 9 publications

References 36 publications

The Filament Lattice of Striated Muscle

The Filament Lattice of Striated Muscle

Raman spectroscopy of cytoplasmic muscle fiber proteins. Orientational order

Extra calcium on shortening in barnacle muscle. Is the decrease in calcium binding related to decreased cross-bridge attachment, force, or length?

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