scholarly journals OBLIQUELY STRIATED MUSCLE

1968 ◽  
Vol 36 (1) ◽  
pp. 245-259 ◽  
Author(s):  
Jack Rosenbluth
Keyword(s):  
Electron Microscopy ◽  
Sarcoplasmic Reticulum ◽  
Connective Tissue ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Body Muscle ◽  
Dense Bodies ◽  
Thick Filaments ◽  
Predominant Type ◽  
Physiological Differences

Body muscle cells of the bloodworm Glycera, a polychaete annelid, were studied by electron microscopy and compared with muscle cells of the more slowly acting nematode Ascaris, which have been described previously. Both muscles are obliquely striated. The predominant type of bloodworm fiber is characterized by a prominent transversely oriented sarcoplasmic reticulum with numerous dyads at the surface of each cell. Thick myofilaments are ∼3 µ long and overlap along ∼60% of their length in extended fibers and ∼80% in shortened fibers. There is virtually no endomysium and very little intracellular skeleton, and the cells are attached by desmosomes to one another rather than to connective tissue. Dense bodies are absent from the fibers and in their place are Z lines, which are truly linear rather than planar. Scattered among the predominant fibers are others, less orderly in arrangement, in which the SR is much less prominent and in which the thick filaments are thicker and longer and overlap to an even smaller degree. It is suggested that physiological differences between bloodworm and Ascaris muscles derive from differences in the proportion of series to parallel linkages between the contractile elements, differences in the amount and disposition of the SR, and differences in the impedance to shear within the myofibrils.

scholarly journals The Regulation of Catch in Molluscan Muscle

1967 ◽  
Vol 50 (6) ◽  
pp. 157-169 ◽  
Author(s):  
Betty M. Twarog
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Striated Muscle ◽  
Smooth Muscles ◽  
Neural Activation ◽  
Thin Filaments ◽  
Dense Bodies ◽  
Thick Filaments

Molluscan catch muscles are smooth muscles. As with mammalian smooth muscles, there is no transverse ordering of filaments or dense bodies. In contrast to mammalian smooth muscles, two size ranges of filaments are present. The thick filaments are long as well as large in diameter and contain paramyosin. The thin filaments contain actin and appear to run into and join the dense bodies. Vesicles are present which may be part of a sarcoplasmic reticulum. Neural activation of contraction in Mytilus muscle is similar to that observed in mammalian smooth muscles, and in some respects to frog striated muscle. The relaxing nerves, which reduce catch, are unique to catch muscles. 5-Hydroxytryptamine, which appears to mediate relaxation, specifically blocks catch tension but increases the ability of the muscle to fire spikes. It is speculated that Mytilus muscle actomyosin is activated by a Ca++-releasing mechanism, and that 5-hydroxytryptamine may reduce catch and increase excitability by influencing the rate of removal of intracellular free Ca++.

scholarly journals THE SARCOPLASMIC RETICULUM IN MUSCLE CELLS OF AMBLYSTOMA LARVAE

1956 ◽  
Vol 2 (4) ◽  
pp. 163-170 ◽  
Author(s):  
Keith R. Porter
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Constant Width ◽  
Muscle Cells ◽  
Cell Types ◽  
Thin Sections ◽  
System A ◽  
Structural Relationships ◽  
Complex Membrane

Electron microscopy of thin sections of muscle fibers in myotomes of Amblystoma larvae has revealed the presence of a complex, membrane-limited system of canaliculi and vesicles which form a lace-like reticulum around and among the myofibrils. This seems to correspond to the sarcoplasmic reticulum of the earlier light microscopists and the endoplasmic reticulum of other cell types. The elements constituting the reticulum are disposed in a pattern which bears a constant relation to the bands of the adjacent myofibrils and is therefore repeated in each sarcomere. At the H band the system is transversely continuous but not so at other levels. Longitudinally continuity is interrupted at the Z bands where large vesicles belonging to adjacent sarcomere segments of the system face off on opposite sides of the band. The opposing faces of these vesicles are flat and separated by a space of more or less constant width, in which are located small, finger-shaped vesicles. In view of these and other close structural relationships with the myofibrils it seems appropriate to assign to the system a role in the conduction of the excitatory impulse.

scholarly journals Characterization of the sarcoplasmic reticulum proteins in the thermogenic muscles of fish.

1994 ◽  
Vol 127 (5) ◽  
pp. 1275-1287 ◽  
Author(s):  
B A Block ◽  
J O'Brien ◽  
G Meissner
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Direct Evidence ◽  
Striated Muscle ◽  
High Capacity ◽  
Muscle Cells ◽  
Immunoblot Analysis ◽  
Fluorescent Labeling ◽  
T Tubules ◽  
The Brain

Marlins, sailfish, spearfishes, and swordfish have extraocular muscles that are modified into thermogenic organs beneath the brain. The modified muscle cells, called heater cells, lack organized myofibrils and are densely packed with sarcoplasmic reticulum (SR), transverse (T) tubules, and mitochondria. Thermogenesis in the modified extraocular muscle fibers is hypothesized to be associated with increased energy turnover due to Ca2+ cycling at the SR. In this study, the proteins associated with sequestering and releasing Ca2+ from the SR (ryanodine receptor, Ca2+ ATPase, calsequestrin) of striated muscle cells were characterized in the heater SR using immunoblot and immunofluorescent techniques. Immunoblot analysis with a monoclonal antibody that recognizes both isoforms of nonmammalian RYRs indicates that the fish heater cells express only the alpha RYR isoform. The calcium dependency of [3H]ryanodine binding to the RYR isoform expressed in heater indicates functional identity with the non-mammalian alpha RYR isoform. Fluorescent labeling demonstrates that the RYR is localized in an anastomosing network throughout the heater cell cytoplasm. Measurements of oxalate supported 45Ca2+ uptake, Ca2+ ATPase activity, and [32P]phosphoenzyme formation demonstrate that the SR contains a high capacity for Ca2+ uptake via an ATP dependent enzyme. Immunoblot analysis of calsequestrin revealed a significant amount of the Ca2+ binding protein in the heater cell SR. The present study provides the first direct evidence that the heater SR system contains the proteins necessary for Ca2+ release, re-uptake and sequestration, thus supporting the hypothesis that thermogenesis in the modified muscle cells is achieved via an ATP-dependent cycling of Ca2+ between the SR and cytosolic compartments.

scholarly journals Ultrastructure of developing human muscle: the problem of multinucleation of striated muscle cells

1986 ◽  
Vol 44 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Guilberto Minguetti ◽  
W. G. P. Mair
Keyword(s):  
Electron Microscopy ◽  
Basement Membrane ◽  
Plasma Membranes ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Human Muscle ◽  
Membrane Tube ◽  
Embryonic Myogenesis ◽  
Human Foetuses

The authors studied by electron microscopy the muscle of 27 human foetuses ranging from 9 weeks to 9 months development. It was possible to observe that disintegration of the plasma membranes of adjacent myoblasts and myotubes which share a common basement membrane tube appears to occur in longitudinally disposed cells of those categories. This may help to explain how further nuclei may be incorporated into well developed myotubes and how the striated muscle cells become multinucleated during embryonic myogenesis and regeneration in vivo.

scholarly journals Intermediate-sized filaments of the prekeratin type in myoepithelial cells.

1980 ◽  
Vol 84 (3) ◽  
pp. 633-654 ◽  
Author(s):  
W W Franke ◽  
E Schmid ◽  
C Freudenstein ◽  
B Appelhans ◽  
M Osborn ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Immunofluorescence Microscopy ◽  
Myogenic Differentiation ◽  
Muscle Cells ◽  
Myoepithelial Cells ◽  
Sweat Glands ◽  
Dense Bodies ◽  
Cell Specialization

Myoepithelial cells from mammary glands, the modified sweat glands of bovine muzzle, and salivary glands have been studied by electron microscopy and by immunofluorescence microscopy in frozen sections in an attempt to further characterize the type of intermediate-sized filaments present in these cells. Electron microscopy has shown that all myoepithelial cells contain extensive meshworks of intermediate-sized (7--11-nm) filaments, many of which are anchored at typical desmosomes or hemidesmosomes. The intermediate-sized filaments are also intimately associated with masses of contractile elements, identified as bundles of typical 5--6-nm microfilaments and with characteristically spaced dense bodies. This organization resembles that described for various smooth muscle cells. In immunofluorescence microscopy, using antibodies specific for the various classes of intermediate-sized filaments, the myoepithelial cells are strongly decorated by antibodies to prekeratin. They are not specifically stained by antibodies to vimentin, which stain mesenchymal cells, nor by antibodies to chick gizzard desmin, which decorate fibrils in smooth muscle Z bands and intercalated disks in skeletal and cardiac muscle of mammals. Myoepithelial cells are also strongly stained by antibodies to actin. The observations show (a) that the epithelial character, as indicated by the presence of intermediate-sized filaments of the prekeratin type, is maintained in the differentiated contractile myoepithelial cell, and (b) that desmin and desmin-containing filaments are not generally associated with musclelike cell specialization for contraction but are specific to myogenic differentiation. The data also suggest that in myoepithelial cells prekeratin filaments are arranged--and might function--in a manner similar to the desmin filaments in smooth muscle cells.

Ultrastructure of the caudal muscle cells in the larva of a polyclinid ascidian

1985 ◽  
Vol 63 (6) ◽  
pp. 1410-1419 ◽  
Author(s):  
Michael J. Cavey ◽  
Harvey D. Strecker
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Striated Muscle ◽  
Muscle Cells ◽  
The Other ◽  
The Cross

Two paraxial bands of somatic striated muscle occur in the tail of the larva of the compound ascidian Aplidium ?constellatum. The mononucleate muscle cells of each band align in longitudinal rows between the epidermis and the notochord. The cross-striated myofibrils, originating and terminating at intermediate junctions on the transverse cellular boundaries, are indiscrete. They follow a spiral course through the subcortical and medullary sarcoplasm, bypassing the nucleus and the other organelles and inclusions in the center of the cell. Cisternae of the sarcoplasmic reticulum envelop the myofibrils, forming compact fenestrated sheets that are continuous between the sarcomeres and locally undifferentiated with respect to the myofibrillar striations. Cisternae of the perifibrillar sarcoplasmic reticulum near each sarcomeric Z-line establish dyadic interior couplings with a network of tubular invaginations of the sarcolemma. The sarcolemmal tubules can originate from any surface, including the transverse cellular boundaries. Near the half I-bands of the terminal sarcomeres at the intermediate junctions, the perifibrillar cisternae frequently leave the fenestrated sheets and extend to the overlying sarcolemma, becoming the sub-sarcolemmal cisternae of dyadic peripheral couplings.

Negative Staining of F-Actin in situ with Tannic Acid

1975 ◽  
Vol 33 ◽  
pp. 628-629
Author(s):  
James R. LaFountain ◽  
Herbert R. Thomas
Keyword(s):  
Electron Microscopy ◽  
Tannic Acid ◽  
Actin Filaments ◽  
Striated Muscle ◽  
Vastus Lateralis ◽  
Muscle Cells ◽  
Cacodylate Buffer ◽  
Spindle Apparatus ◽  
Ultrastructural Findings

Since the introduction of tannic acid as an additive in glutaraldehyde fixatives for electron microscopy, there have been numerous reports of ultrastructural findings that were not detectable after fixation without tannic acid. We have used tannic acid in studies on the spindle apparatus in insect spermatocytes to show that microtubules of the spindle are composed of 13 protofilaments. Tannic acid accumulates at the periphery of subunits of microtubules and with osmium stains those regions, leaving the subunits unstained. Hence, the subunits appear negatively stained.We have found that in addition to microtubules, other filamentous structures in cells appear negatively stained after fixation with glutaraldehyde-tannic acid. The most noteable are actin filaments in muscle cells. We report here results obtained from mouse striated muscle.Segments of gastrocnemius and vastus lateralis muscles are dissected in 3% glutaraldehyde in 0.1 M cacodylate buffer and subsequently fixed for 1 hr in the above fixative containing tannic acid (Mallinckrodt) in concentrations of 4 and 8%. Both concentrations gave similar results.

Origin of the irideal striated muscle in birds

Development ◽  
1985 ◽  
Vol 88 (1) ◽  
pp. 1-13
Author(s):  
Kensuke E. Nakano ◽  
Harukazu Nakamura
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stromal Cells ◽  
Striated Muscle ◽  
Muscle Cells ◽  
Chick Embryos ◽  
Dorsal Part ◽  
Nuclear Marker ◽  
Transmission Electron ◽  
The Right

The aim of the present study was to elucidate the origin of the striated muscle cells in the avian iris. For this purpose we adopted interspecific transplantation between quail and chick embryos because quail cells can be used as biological markers in this system. We transplanted isotopically and isochronically (6- to 7-somite stage) a fragment of a dorsal part of the quail neural anlage into a chick embryo at the level corresponding to the posterior prosencephalon and the mesencephalon on the right-hand side. In the chimaeric embryo, the iris epithelium comprised host chick cells, while most of the stromal cells of the iris on the operated side possessed the quail nuclear marker. At 19 days after the operation, the striated muscle cells had differentiated in the chimaeric embryo. These cells, as well as connective tissue cells and the Schwann cells of the iris of the chimaera, were shown to possess typical quail nuclei by light and transmission electron microscopy. From these findings, we conclude that the striated muscle cells originate from the neural crest.

scholarly journals An Electron Microscope Study of Smooth Muscle in Pregnant Uterus of the Rabbit

1958 ◽  
Vol 4 (5) ◽  
pp. 609-614 ◽  
Author(s):  
C. F. Shoenberg
Keyword(s):  
Smooth Muscle ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Connective Tissue ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Muscle Cells ◽  
Pregnant Uterus

In the smooth muscle of the rabbit uterus one type of myofilament can be found; this is about 50 A thick. In the sarcoplasmic reticulum there are smooth walled vesicles and many vesicles with particles attached. It is suggested that these particles may correspond to the ribonucleoprotein-containing particles of Palade and Siekevitz. The diameter of the particles is 250 A. There are also unattached particles some of which may be glycogen. The membranes of the muscle cells and the connective tissue lying between them are described.

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