scholarly journals Series Elasticity in Frog Muscle as Revealed by Optical Diffraction

1982 ◽  
Vol 35 (6) ◽  
pp. 617
Author(s):  
Julian A Barden ◽  
Peter Mason
Keyword(s):  
Sarcomere Length ◽  
Striated Muscle ◽  
Small Population ◽  
Frog Muscle ◽  
Optical Diffraction ◽  
Muscle Fibres ◽  
Series Elasticity ◽  
Thick Filaments ◽  
Cross Bridges ◽  
Made In

Using an optical diffraction technique, the series elasticity of frog striated muscle fibres was investigated. One source of series elasticity was located in the cross-bridges during the application of either quick stretches or releases of muscle fibres. Evidence is presented here for a second component attributable to a small population of slowly activated sarcomeres. The size of the second component was progressively reduced until it virtually disappeared at a sarcomere length of 3 pm. A third component appears to reside in the thick filaments. Calculation of the elastic energy in the muscle fibres enabled an identification of the source of the energy to be made in terms of the components of the series elasticity. Evidence is presented of a short-range elastic component present in resting fibres.

scholarly journals Length-tension relation in Limulus striated muscle.

1980 ◽  
Vol 87 (1) ◽  
pp. 204-208 ◽  
Author(s):  
B Walcott ◽  
M M Dewey
Keyword(s):  
Horseshoe Crab ◽  
Sarcomere Length ◽  
Striated Muscle ◽  
Laser Diffraction ◽  
Frog Muscle ◽  
Constant Length ◽  
Maximum Tension ◽  
Thick Filaments ◽  
Average Maximum ◽  
Length Range

Laser diffraction techniques coupled with simultaneous tension measurements were used to determine the length-tension relation in intact, small (0.5-mm thick, 10-mm wide, 20-25-mm long) bundles of a Limulus (horseshoe crab) striated muscle, the telson levator muscle. This muscle differs from the model vertebrate systems in that the thick filaments are not of a constant length, but shorten from 4.9 to approximately 2.0 micrometers as the sarcomeres shorten from 7 to 3 micrometers. In the Limulus muscle, the length-tension relation plateaued to an average maximum tension of 0.34 N/mm2 at a sarcomere length of 6.5 micrometers (Lo) to 8.0 micrometers. In the sarcomere length range from 3.8 to 12.5 micrometers, the muscle developed 50% or more of the maximum tension. When the sarcomere lengths are normalized (expressed as L/Lo) and the Limulus data are compared to those from frog muscle, it is apparent that Limulus muscle develops tension over a relatively greater range of sarcomere lengths.

scholarly journals Resting myosin cross-bridge configuration in frog muscle thick filaments.

1986 ◽  
Vol 102 (2) ◽  
pp. 610-618 ◽  
Author(s):  
M Cantino ◽  
J Squire
Keyword(s):  
Myosin Head ◽  
Freeze Fracture ◽  
Optical Diffraction ◽  
Outer Diameter ◽  
X Ray ◽  
Cross Bridge ◽  
Thick Filaments ◽  
Myosin Filaments ◽  
Cross Bridges ◽  
The Right

Clear images of myosin filaments have been seen in shadowed freeze-fracture replicas of single fibers of relaxed frog semitendinosus muscles rapidly frozen using a dual propane jet freezing device. These images have been analyzed by optical diffraction and computer averaging and have been modelled to reveal details of the myosin head configuration on the right-handed, three-stranded helix of cross-bridges. Both the characteristic 430-A and 140-150-A repeats of the myosin cross-bridge array could be seen. The measured filament backbone diameter was 140-160 A, and the outer diameter of the cross-bridge array was 300 A. Evidence is presented that suggests that the observed images are consistent with a model in which both of the heads of one myosin molecule tilt in the same direction at an angle of approximately 50-70 degrees to the normal to the filament long axis and are slewed so that they lie alongside each other and their radially projected density lies along the three right-handed helical tracks. Any perturbation of the myosin heads away from their ideal lattice sites needed to account for x-ray reflections not predicted for a perfect helix must be essentially along the three helical tracks of cross-bridges. Little trace of the presence of non-myosin proteins could be seen.

scholarly journals Polarization of Tryptophan Fluorescence from Single Striated Muscle Fibers

1972 ◽  
Vol 59 (1) ◽  
pp. 103-120 ◽  
Author(s):  
C. G. dos Remedios ◽  
R. G. C. Millikan ◽  
M. F. Morales
Keyword(s):  
Sarcomere Length ◽  
Striated Muscle ◽  
Muscle Fibers ◽  
Tryptophan Fluorescence ◽  
Thin Filaments ◽  
A Value ◽  
Striated Muscle Fibers ◽  
Types Of Muscle Fibers ◽  
Cross Bridges ◽  
Contraction And Relaxation

Instrumentation has been developed to detect rapidly the polarization of tryptophan fluorescence from single muscle fibers in rigor, relaxation, and contraction. The polarization parameter (P⊥) obtained by exiciting the muscle tryptophans with light polarized perpendicular to the long axis of the muscle fiber had a magnitude P⊥ (relaxation) > P⊥ (contraction) > P⊥ (rigor) for the three types of muscle fibers examined (glycerinated rabbit psoas, glycerinated dorsal longitudinal flight muscle of Lethocerus americanus, and live semitendinosus of Rana pipiens). P⊥ from single psoas fibers in rigor was found to increase as the sarcomere length increased but in relaxed fibers P⊥ was independent of sarcomere length. After rigor, pyrophosphate produced little or no change in P⊥, but following an adenosine triphosphate (ATP)-containing solution, pyrophosphate produced a value of P⊥ that fell between the contraction and relaxation values. Sinusoidal or square wave oscillations of the muscle of amplitude 0.5–2.0% of the sarcomere length and frequency 1, 2, or 5 Hz were applied in rigor when the myosin cross-bridges are considered to be firmly attached to the thin filaments. No significant changes in P⊥ were observed in either rigor or relaxation. The preceding results together with our present knowledge of tryptophan distribution in the contractile proteins has led us to the conclusion that the parameter P⊥ is a probe of the contractile state of myosin which is probably sensitive to the orientation of the myosin S1 subfragment.

scholarly journals An electron microscopic and optical diffraction analysis of the structure of Limulus telson muscle thick filaments.

1982 ◽  
Vol 92 (2) ◽  
pp. 443-451 ◽  
Author(s):  
R W Kensler ◽  
R J Levine
Keyword(s):  
Electron Microscopy ◽  
Diffraction Analysis ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Thick Filaments ◽  
Diffraction Patterns ◽  
Cross Bridges

Long, thick filaments (greater than 4.0 micrometer) rapidly and gently isolated from fresh, unstimulated Limulus muscle by an improved procedure have been examined by electron microscopy and optical diffraction. Images of negatively stained filaments appear highly periodic with a well-preserved myosin cross-bridge array. Optical diffraction patterns of the electron micrographs show a wealth of detail and are consistent with a myosin helical repeat of 43.8 nm, similar to that observed by x-ray diffraction. Analysis of the optical diffraction patterns, in conjunction with the appearance in electron micrographs of the filaments, supports a model for the filament in which the myosin cross-bridges are arranged on a four-stranded helix, with 12 cross-bridges per turn or each helix, thus giving an axial repeat every third level of cross-bridges (43.8 nm).

scholarly journals Structure and paramyosin content of tarantula thick filaments.

1983 ◽  
Vol 97 (1) ◽  
pp. 186-195 ◽  
Author(s):  
R J Levine ◽  
R W Kensler ◽  
M C Reedy ◽  
W Hofmann ◽  
H A King
Keyword(s):  
Evolutionary Relationship ◽  
Radial Distance ◽  
Thick Filament ◽  
Optical Diffraction ◽  
Thin Filaments ◽  
Biochemical Characteristics ◽  
Thick Filaments ◽  
Cross Bridges ◽  
Centers Of Mass ◽  
Relationship Of

Muscle fibers of the tarantula femur exhibit structural and biochemical characteristics similar to those of other long-sarcomere invertebrate muscles, having long A-bands and long thick filaments. 9-12 thin filaments surround each thick filament. Tarantula muscle has a paramyosin:myosin heavy chain molecular ratio of 0.31 +/- 0.079 SD. We studied the myosin cross-bridge arrangement on the surface of tarantula thick filaments on isolated, negatively stained, and unidirectionally metal-shadowed specimens by electron microscopy and optical diffraction and filtering and found it to be similar to that previously described for the thick filaments of muscle of the closely related chelicerate arthropod, Limulus. Cross-bridges are disposed in a four-stranded right-handed helical arrangement, with 14.5-nm axial spacing between successive levels of four bridges, and a helical repeat period every 43.5 nm. The orientation of cross-bridges on the surface of tarantula filaments is also likely to be very similar to that on Limulus filaments as suggested by the similarity between filtered images of the two types of filaments and the radial distance of the centers of mass of the cross-bridges from the surfaces of both types of filaments. Tarantula filaments, however, have smaller diameters than Limulus filaments, contain less paramyosin, and display structure that probably reflects the organization of the filament backbone which is not as apparent in images of Limulus filaments. We suggest that the similarities between Limulus and tarantula thick filaments may be governed, in part, by the close evolutionary relationship of the two species.

Sarcomere length behaviour along single frog muscle fibres at different lengths during isometric tetani

1989 ◽  
Vol 10 (1) ◽  
pp. 67-84 ◽  
Author(s):  
Kevin Burton ◽  
William N. Zagotta ◽  
Ronald J. Baskin
Keyword(s):  
Sarcomere Length ◽  
Frog Muscle ◽  
Muscle Fibres

Storage and release of mechanical energy by active muscle: a non-elastic mechanism?

1985 ◽  
Vol 115 (1) ◽  
pp. 79-87 ◽  
Author(s):  
G. A. Cavagna ◽  
M. Mazzanti ◽  
N. C. Heglund ◽  
G. Citterio
Keyword(s):  
Isometric Contraction ◽  
Sarcomere Length ◽  
Mechanical Energy ◽  
Frog Muscle ◽  
Muscle Fibres ◽  
Elastic Recoil ◽  
Active Muscle ◽  
A Value ◽  
Elastic Mechanism ◽  
Isotonic Shortening

In frog muscle fibres, tetanically stimulated at a sarcomere length of about 2 micron, stretched at a velocity of 1 lengths-1 and released against a force equal to the maximum isometric, P0, a phase of rapid isotonic shortening takes place after release. As the amplitude of the stretch is increased from 1.5 to 9% of the initial length: (1) the amount of rapid isotonic shortening increases up to 9–10 nm per half sarcomere and (2) the stiffness of the fibre (an indication of the number of bridges attached) decreases to a value about equal to that measured during an isometric contraction. If a 5–10 ms delay is left between the end of stretch and release, the amount of rapid isotonic shortening increases to about 12 nm hs-1. A 300–500 ms delay, however, results in a decrease in rapid isotonic shortening to about 5 nm hs-1 and also results in a velocity transients against P0 that are similar to those described during release from a state of isometric contraction. It is concluded that the force attained after large, fast stretches is due to a greater force developed by each bridge and not to a greater number of bridges. After the elastic recoil (when the force is suddenly reduced to P0), these strained bridges are able to shorten by about 12 nm hs-1, suggesting that, during and immediately after stretching, they are charged to levels of potential energy greater than those attained in an isometric contraction.

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