Cross-striated Muscle Research Articles

Major myofibrillar protein content and the structure of mollusc adductor contractile apparatus

1. 1. The adductor muscles of seven different mollusc species were subjected to a morphobiochemical investigation in order to find a relation between the structure and protein composition of their contractile systems. 2. 2. The ultrastructure was studied by electron microscopy. Electrophoresis was used for determination of the weight ratios between the major contractile proteins: myosin, paramyosin, actin and tropomyosin. 3. 3. The data, presented in this paper, shows that muscles may be arranged according to their morphological and biochemical characteristics. 4. 4. Each sequence has two endings: Mya smooth and Pecten cross-striated muscles or vice versa. 5. 5. It is shown that the growth of the myosin:actin relation is accompanied by the enhancement of muscle structural regularity. 6. 6. Simultaneously with the increase of the myosin relative content and the number of thick filaments the diameters of the latter decrease upon the fall of the paramyosin content.

Nicotinic cholinergic stimulation increases cyclic GMP levels in vertebrate skeletal muscle

CYCLIC GMP seems to be an intracellular second messenger for certain actions of acetylcholine at muscarinic receptors (for a review, see ref. 1). For example, previous studies have provided evidence that activation of muscarinic, but not of nicotinic, cholinergic receptors leads to an increase in the level of cyclic GMP in many tissues2–8, including smooth muscle3–5. Also, it has been demonstrated that contraction of cross-striated muscle fibres of the giant barnacle elicited by nerve stimulation is associated with an increase in the level of muscle cyclic GMP9. These observations prompted us to determine whether a similar cyclic GMP increase is associated with contractile activity in vertebrate skeletal muscle. We report here that activation of a nicotinic cholinergic synapse raises the level of cyclic GMP in frog skeletal muscle. As in smooth4,5 and in barnacle9 muscle, this cyclic GMP increase in vertebrate skeletal muscle is a consequence of a neurotransmitter-induced depolarisation of the muscle membrane.

A diffractometer using a lateral effect photodiode for the rapid determination of sarcomere length changes in cross-striated muscle

A simple method is devised to record rapid sarcomere length changes of muscle fibres using a lateral effect diode. In the standard position the diffractometer records length changes between 1.65 and 3.8 micron, the output being linear 1 V/micron with a frequency response of -3 dB at 1.2 kHz. The absolute error is less than 0.05 micron between 1.65 and 2.80 micron and less than 0.1 micron between 2.81 and 3.30 micron. The resolution of length changes is less than 0.005 micron over the whole range. By varying the detector position the length range can be extended to either side, and spatial resolution can be improved at the expense of length range.

Cytosolic organization of carbohydrate-metabolism enzymes in cross-striated muscle.

Cytosolic organization of carbohydrate-metabolism enzymes in cross-striated muscle.

Autografting of whole muscles in reptiles

Autografting (reimplantation) of the whole gastrocnemius muscle was carried out in turtles (Testudo horsfieldi) weighing 300–500 g. The grafts were investigated 2 weeks to 6 months after transplantation. After 5–6 months the reimplanted muscles were similar in color and shape to the intact symmetrical muscles and they amounted to 77% of their weight. Regeneration was observed in the grafts, but its course was slower than in mammals. Separation of myoblasts from disintegrating muscle fibers of the graft took place rapidly during the first month and continued until 2 months after grafting. Simultaneously, differentiation of myogenic elements into cross-striated muscle fibers and vascularization of the grafts were observed. Most of the grafts by the end of the period of investigation had a muscular type of structure, although considerable variability was observed in the diameter of the muscle fibers.

Increased cyclic GMP levels associated with contraction in muscle fibres of the giant barnacle

CYCLIC GMP has been implicated as an intracellular second messenger in a variety of systems. In particular, a number of hormones and neurotransmitters have been shown to raise cellular cyclic GMP levels in vitro1–9. In many of these systems, however, Ca2+ entry seems to be responsible both for the physiological effect of the hormone and for the hormone-stimulated increase in cyclic GMP (refs 4–9). We have investigated the relationship between calcium and cyclic GMP levels in muscles of the giant barnacle Balanus nubilus. This preparation has a number of advantages. Within fairly narrow limits intracellular free calcium levels in the resting muscle are known10. The depolarisation-induced increase in free calcium, and the resulting activation of contraction, have also been extensively documented10,11. In addition, the depolarisation-induced changes in intracellular free calcium can be easily manipulated because the extracellular fluid is the apparent source of the calcium which couples excitation to contraction12. We report here that either KC1 depolarisation or nerve stimulation increases the cyclic GMP content of barnacle muscle. This increase seems to be associated with Ca2+ entry rather than with a neurotransmitter–receptor interaction per se. This is the first report of an increase in cyclic GMP associated with contractile activity in cross-striated muscle.

An ultrastructural study of the musculature of the pond snail Lymnaea stagnalis (l.).

The ultrastructure of the musculature of Lymnaea stagnalis was studied. Each of the six muscle systems of the body wall, previously distinguished in an anatomical study, has its own type of smooth muscle, characterised by the size and number of the myofilaments, number of mitochondria and distribution of smooth endoplasmic reticulum. The visceral musculature comprises both smooth and striated muscle. Cross-striated muscle is found in the heart and proximal aorta, obliquely striated muscle in the buccal mass, gizzard and vas deferens. Myofibroblasts and myoendothelial cells were also distinguished. On the basis of the observations it is concluded that striated muscles in L. stagnalis contract and relax more rapidly and have a higher endurance than smooth muscles, but that the latter can contract over a wider range. Among smooth muscles the head retractor muscle contracts most rapidly, the shell muscle is most powerful and the diagonal muscle is slow to contract but has a relatively high endurance. The latter muscle, together with the horizontal foot muscle, plays a major role in maintenance of the hydrostatic skeleton. A model for the organisation of the smooth muscles is deduced from the ultrastructural observations. It implies that the myosin-paramyosin filaments change their actin filament partners during contraction. This agrees with a model deduced for other smooth muscles on the basis of physiological experiments and X-ray diffraction analysis.

The ultrastructure of the marine gastrotrichTurbanella cornuta Remane (Macrodasyoidea) and its functional and phylogenetical importance

The organization of marine gastrotrichs (Macrodasyoidea) is reviewed by ultrastructural analysis of one representative,Turbanella cornuta Remane, and the fine structure of tissues and cells is described. Turbanella cornuta has a mono-layeredcellular epidermis rich withsensory hairs, epidermal bodies, isolatedepidermal glands, glandular adhesive organs belonging to a duo-gland type, andventral ciliated epidermal cells of the multiciliated type. The voluminous neuropil of thebrain consists of a circular commissure which sends out four anterior and posterior longitudinal headnerves. The posterior ones unite on each side to one single longitudinal nerve of the periphery which is occupied with single peripheral neurons and has thin commissures that make it anorthogon. The position and the structure of the neurons indicate their sensitive, associative, motoric, and neurosecretory functions. The different forms of synapses give first hints to neuronal connections within gastrotrichs. There is a big cellularglia around the brain commissure and a small cellular glia within the brain neurons. In between the cross-striated muscle fibrils of thepharyngeal wall there are also nerves and sensory hairs. TheY-organ lies in the interior of the lateral body cavities, which are delimited by an outer musculature of the body wall and an inner musculature of the intestinal tract. In the pharyngeal region, theY-organ fills the body cavities completely and, in the intestinal region, it covers thegonads, which also lie in the lateral body cavities, dorsally. The testicles lie separately in front of the paired ovaries. Single states of oogenesis could be identified as oogonia, and young and old oocytes. There is a paired gland organ in front of the dorsomedian ovary which may produce a mucous cover for the egg. Theintestinal tract is adapted to mechanical stress by a myoepithelium in the pharyngeal region, by various interdigitations, and by narrow intercellular gaps with hemidesmosomal adhesions to the basement membrane. The majority of the resorbing intestinal cells have a high seam of microvilli and contain various numbers of lysosomes. In addition, there are some secerning cells without microvilli, but with a centrically arranged ER and with big secretion granules in the dorsomedian sector. The ultrastructure affirms a close correlation between the conditions of life in the interstitium and structural adaptations, such as may be observed in single structures of the body wall, the y-organ, the intestinal tract and, in some respect, even in the nervous system and in the formerly researched musculature and spermatohistogenesis. On the other hand, for the construction of the glandular adhesive organs, the nervous system, and the formerly investigated body cavities, a phylogenetical relevance is discussed. Thereafter, gastrotrichs have more primitive characters than the closely related nematodes.

Studies on the fine structure of cercarial tail muscle of Schistosoma sp. (trematoda)

Three muscle cell types occur in the forked tail of Schistosoma sp. (Trematoda) cercarial larvae. These include a fast, cross-striated muscle functioning in rapid tail movements; a slow, smooth muscle at the body-tail juncture functioning in body and tail shape changes; and a slow, smooth muscle in the tail forks functioning to maintain fork ridgidity during backward swimming movements. The cross-straited muscle observed in this study is unique to platyhelminthes. The striations are the result of transversely aligned Z densities interspersed with branched elements of subsurface sarcoplasmic reticulum cisternae. The myofibrils of striated muscle cells are divided into sarcomeres with typical A and I bands reflecting overlapping thick and thin myofilaments. The smooth muscle cells found at the body-tail juncture are typical for platyhelminthes. They contain irregularly arranged Z densities, overlapping thick and thin myofilaments, and small amounts of subsurface sarcoplasmic reticulum cisternae. The smooth muscle cells found in the two caudal branched forks of the tail are unique in that their thick filaments exhibit a repeating cross-period striation of 350 to 400 A. The morphology of these three muscle cell types is a direct reflection of the three functions known to occur during backward and forward swimming movements in forked tail cercarial larvae.

Effects of myasthenic sera on cultured muscle

Serum from 17 myasthenic patients was added to mouse somite cultures containing mature cross-striated muscle fibers. Myolysis occurred after 24 hr exposure to the serum of three patients. These findings are discussed in relationship to the pathogenesis of myasthenic gravis.

The immunological specificity of myosins from cross-striated muscles as revealed by quantitative microcomplement fixation and enzyme inhibition by antisera

The immunological properties of myosins, especially their muscle-type, class and species specificity, are still controversial. It is the opinion of the authors that the lack of agreement might at least in part be due to the use of contaminated myosins as immunogens and inappropriate methods. We, therefore, purified myosins to a very high degree (≈99%) and induced antisera in guinea-pigs. Studies of quantitative microcomplement fixation and enzyme-inhibition by antisera yielded the following results: myosins of cross-striated muscle have an absolute class, a very pronounced muscle-type and a low species specificity. It can be shown that even a very small contamination of myosins with other proteins could seriously hamper the experiments and that the results obtained depend significantly on the immunological methods employed.

Studies on chromoproteins of cardiac and skeletal muscle of caimans (Caiman sclerops)

In a number of caimans (Caiman sclerops) we were unable to find traces of myoglobin in any of the histologically clearly cross-striated cardiac and skeletal muscles using spectrometric methods. The red colour of the heart is due to a high concentration of cytochrome c. This substance was also found in the muscles of the neck, back, tail, and the anterior extremities.

Paramyosin from arthropod cross-striated muscle

1. 1. Paramyosin was isolated and purified from acetone powders and fresh cross-striated muscle of Limulus polyphemus, the horseshoe crab. The purified protein exhibited a single peak in the ultracentrifuge and a single band in disc-gel electrophoresis. 2. 2. Limulus paramyosin contained a high content a Asp and Glu comparable to other paramyosins and from optical rotatory dispersion and circular dichroism measurements appeared to be about 80% α-helical. 3. 3. Only the PI 2 5 and DIII forms of paracrystals have been obtained but these gave a major repeat pattern averaging 726 Å; comparable Mercenaria mercenaria paracrystals gave, in our hands, a major period of 723 Å. 4. 4. An intrinsic viscosity of 1·99 and 2·38 dl/g for Mercenaria and paramyosins, respectively, indicates different sized molecules. This agrees with the differences in S 20,w 0 for the two, 3·40 and 4·07 S, Mercenaria and Limulus respectively, as well as with the different molecular weights, 208,000 Daltons ( Mercenaria) and 284,000 Daltons ( Limulus) determined by extrapolation of Archibald and meniscus electrophoresis of the two different paramyosins previously incubated in 8 M urea also indicate a larger chain weight for the Limulus paramyosin than for the Mercenaria.

Gross Morphology and Histology of the Musculature of the Freshwater Pulmonate Lymnaea Stagnalis (L.)

The anatomy and light microscopy of the musculature of Lymnaea stagnalis have been studied. Special attention was paid to the structure of the body wall and to its role in maintaining the hydrostatic skeleton. The body wall comprises six muscle systems: 1. circular muscle, 2. diagonal muscle, 3. longitudinal muscle, 4. ventral tentacle retractor muscle, 5. columellar muscle, and 6. horizontal foot muscle. The function of these muscle systems in maintaining the form of the body and in retraction is discussed. The internal organs are divided into three groups, according to the pattern of their musculature. The first group comprises the highly muscular organs; the second group consists of the tubular organs which have a muscular sheath and the third group is made up of those organs which have only a thin connective tissue capsule containing scattered muscle cells. The body wall musculature and most of the visceral musculature, is composed of smooth muscle fibres. Cross-striated muscle was found in the heart. The muscles of the buccal mass, the gizzard and the vas deferens are obliquely striated. Most of the musculature consists of white muscle. The gizzard and the buccal mass are red, probably due to the presence of some type of myoglobin.

Rhabdomyomatous dysplasia of the lung.

Case report of a 4 months old child with systemic involvement of cross-striated muscle tissue of different grade of maturity in alveolar septa and bronchial walls of a hypoplastic lung. After a morphological description, a short review of the literature is followed by the discussion of formal pathogenesis of this rare pulmonary malformation.

Mechanism of changes in the polarization of cross-striated muscle fibers in experimental botulism and denervation

Mechanism of changes in the polarization of cross-striated muscle fibers in experimental botulism and denervation

Development of action potentials in a clonal rat skeletal muscle cell line.

THE development of the action potential mechanism has been studied during the differentiation of myoblasts into cross-striated muscle fibres. A clonal line of muscle cells isolated from rat thigh was used1 because this provides a homogeneous population of cells easily accessible for electrophysiological studies and biochemical analysis. This system provides a useful model for studying the differentiation of mammalian skeletal muscle.

Ultrastructures tegumentaires chez un crustace copepode cletocamptus retrogressus

The cuticle, the epidermis, the cross-striated muscle cells, their attachments and some sensory endings of this planctonic Crustacean, have been observed and are briefly described. The twisted system and the differentiation of hexagonal patterns have been studied with the electron microscope, mainly in the outer levels of the procuticle. Comparisons with other Cuticular patterns and with physical systems are discussed.

Fine structure and contraction of isolated muscle actomyosin. I. Evidence for a sliding mechanism by means of oligomeric myosin.

The investigation of thread models of actomyosin isolated from cross-striated muscle has led to the following results: 1) Passive stretch and isometric contraction cause a parallel alignment of the filaments from an originally random network. 2) Parallel orientation of the filaments favors the unidirectional contraction of the thread models and decreases their capability of volume contraction. 3) Contraction by ATP results in a condensation of the filamentous system regardless of whether it is oriented or not. 4) Uncontracted threads consist of actin filaments, which are loaded with myosin molecules in the arrowhead pattern and interconnected by oligomeric myosin bridges, whereas contracted threads are made up of both actin and myosin filaments. 5) Contraction of the thread models is brought about by a sliding mechanism that starts from oligomeric myosin units and leads to the formation of myosin filaments.

The Cross Striated Muscle of Chordata

The Cross Striated Muscle of Chordata