STRUCTURE OF <i>LIMULUS</i> STRIATED MUSCLE

Dewey, Maynard M.; Levine, Rhea J. C.; Colflesh, David E.

doi:10.1083/jcb.58.3.574

Cited by 35 publications

(22 citation statements)

References 29 publications

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“…de Villafranca (4) was the first to report extensive changes in A-band length with sarcomere length in glycerinated Limulus muscle . This was confirmed by Dewey et al (6), who additionally demonstrated by electron microscope observations that the shortening ofthe A-band below 5 ftm resulted from $hortening of the thick filaments. This observation was confirmed by a series of experiments in which thick filaments were isolated from muscle at different sarcomere lengths (8) .…”

supporting

confidence: 72%

“…As the sarcomeres shorten below 6.5 lam in length, the thick filaments of the A-band also shorten (6,7,8). Thus, an 1-band always appears to be present even though extensive sarcomere shortening has occurred .…”

Section: Discussionmentioning

confidence: 90%

“…In frog muscle, Gordon et al (9) interpreted this region to extend from where there was maximum overlap between thick and thin filaments to the shorter sarcomere length where thin filaments from opposite Z-disks begin to interfere . In Limulus this does not seem to be the case; Lo seems to occur when the thick filaments are at their maximum length and yet are still relatively aligned with each other (6) . At this point, the overlap of the thin filament over the thick is only -68% of the maximum possible.…”

Section: Discussionmentioning

confidence: 95%

“…This provided a positive print and a negative . The sarcomere length could be roughly determined by measuring the distance between the middle of the first-order layer lines on the print, dividing by two, and placing that value in Bragg's equation (3,5,6) . In addition, the distance between the muscle bundle and film was measured with calipers and was accurate to within ± 0 .5 nun .…”

Section: Laser Diffraction Image Analysismentioning

confidence: 99%

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Length-tension relation in Limulus striated muscle.

Walcott¹,

Dewey²

1980

The Journal of Cell Biology

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Laser diffraction techniques coupled with simultaneous tension measurements were used to determine the length-tension relation in intact, small (0.5-mm thick, 1 .0-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 -2 .0 ttm as the sarcomeres shorten from 7 to 3 ttm.In the Limulus muscle, the length-tension relation plateaued to an average maximum tension of 0.34 N/m m 2 at a sarcomere length of 6.5 ,um (Lo) to 8.0 ttm . In the sarcomere length range from 3.8 to 12 .5 ttm, 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.Evidence is nearly irrefutable that, in vertebrate striated muscle, shortening of sarcomeres is accompanied structurally by a reduction in 1-band width and by a constancy of the A-band width. This observation, in addition to the evidence for the constancy of lengths of the thick and thin filaments that make up the A-and I-bands, has led to the generally accepted slidingfilament theory of muscle contraction proposed by Huxley and co-workers (10, 11) . Further support ofthis theory is the lengthtension data ofGordon et al. (9), which suggest that the amount of isometric tension developed by a vertebrate striated muscle fiber is determined by the degree of overlap of the thick and thin filaments and thus, presumably, the number of myosin bridges that can interact with actin .In one invertebrate muscle, however, it has been shown that a basic tenet of the sliding-filament model is not followed; in Limulus telson levator muscle the A-bands and constitutive thick filaments change length with sarcomere length. de Villafranca (4) was the first to report extensive changes in A-band length with sarcomere length in glycerinated Limulus muscle . This was confirmed by Dewey et al. (6), who additionally demonstrated by electron microscope observations that the shortening ofthe A-band below 5 ftm resulted from $hortening of the thick filaments. This observation was confirmed by a series of experiments in which thick filaments were isolated from muscle at different sarcomere lengths (8) . Long, thick filaments (-4.2 ttm) were isolated from muscles with long sarcomeres (8 pm), whereas short, thick filaments (-2 .9 /m) were isolated from muscle with short sarcomeres (6 lilm).Given this significant variation from the structural aspect of the vertebrate system and model, the question arises as to its 204 effect on the function of the Limulus muscle. Therefore, we have determined the length-tension diagram for Limulus telson muscle and have correlated it with structural information previously determined. MATERIALS AND METHODSAdult Limulus (20-30 cm across the carapace) were obtained from...

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supporting

confidence: 72%

Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 95%

Section: Laser Diffraction Image Analysismentioning

confidence: 99%

See 2 more Smart Citations

Length-tension relation in Limulus striated muscle.

Walcott¹,

Dewey²

1980

The Journal of Cell Biology

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“…A change in cross-sectional appearance of these filaments may thus accompany a change in filament length. We have seen both hollow and solid profiles of thick filaments in Limulus telson muscle (4), but at this time we cannot determine whether these differences are due to variations in molecular packing (i.e. the presence or absence of paramyosin) normally occurring along the length of the filaments, or changes in filament organization occurring during shortening.…”

Section: The Roles Of Paramyosin In Muscle Functionmentioning

confidence: 98%

Paramyosin in invertebrate muscles. II. Content in relation to structure and function.

Levine¹,

Elfvin²,

Dewey³

et al. 1976

The Journal of Cell Biology

109

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By quantitative sodium dodecyl sulfate-polyacrylamide gel electrophoresis, paramyosin:myosin heavy chain molecular ratios were calculated for three molluscan muscles: Aequipecten striated adductor, Mercenaria opaque adductor, and Mytilus anterior byssus retractor; and four arthropodan muscles: Limulus telson, Homarus slow claw, Balanus scutal depressor, and Lethocerus air tube retractor. These ratios correlate positively with both thick filament dimensions and maximum active tension development in these tissues. The role of paramyosin in these muscles is discussed with respect to the following characteristics: force development, "catch," and extreme reversible changes in length.The paramyosin content of molluscan muscle has been observed to vary (a) with the structural organization of fibers, and (b) with the dimensions of the thick filaments. A paramyosin:myosin ratio greater than 1:1 has been reported for lamellibranch smooth adductors (30, 32). Obliquely and cross-striated adductors have been reported to contain proportionally less (1:2 and 1:3, respectively) of this protein (30, 32). In such molluscan smooth "catch" muscles as lamellibranch opaque adductors (6-8, 10-12, 20, 27) and Mytilus anterior byssus retractor muscle (ABRM) (18,20,21,26,28, 32), thick filaments range from 500 to 1,500 /~ in diameter and from 10 to 40 tzm in length. They are oriented parallel to the cells, but are not organized into identifiable ordered, repeating sarcomeric units (33). The cross-striated adductors of the lamellibranch Aequipecten, on the other hand, resemble vertebrate striated muscle with respect to both filament dimensions and sarcomere organization (24).In previous papers (1, 5, 19) we and others reported the identification of paramyosin as a component of striated arthropod muscles, by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and immunodiffusion. We also showed that the arthropodan and molluscan paramyosins in homogenates of glycerinated muscle have identical chain weights, and further, that this protein is similar enough in these different muscles to cross-react immunologically across phyletic lines.Here we report the paramyosin:myosin heavy chain ratios in the following arthropodan muscles:Limulus telson levator, Hornarus slow claw muscle, Balanus scutal depressor, and Lethocerus air tube retractor; as well as in the following molluscan muscles: Aequipecten striated adductor, Mytilus ABRM, and Mercenaria opaque adductor.The correlation between paramyosin content, filament dimensions, and maximum active tension development is discussed in relation to the functional role of paramyosin in these muscles.

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