scholarly journals An antiactin antibody that distinguishes between cytoplasmic and skeletal muscle actins.

1980 ◽  
Vol 86 (3) ◽  
pp. 891-897 ◽  
Author(s):  
B W Lubit ◽  
J H Schwartz
Keyword(s):  
Skeletal Muscle ◽  
Body Wall ◽  
Human Fibroblasts ◽  
Aplysia Californica ◽  
Membrane Systems ◽  
Intense Staining ◽  
Marine Mollusc ◽  
Cytoplasmic Actin ◽  
Great Excess ◽  
Immunocytochemical Studies

We elicited antibodies in rabbits to actin purified from body wall muscle of the marine mollusc, Aplysia californica. We found that this antiactin has an unusual specificity: in addition to reacting with the immunogen, it recognizes cytoplasmic vertebrate actins but not myofibrillar actin. Radioimmunoassay showed little or no cross-reaction with actin purified from either chicken gizzard or rabbit skeletal muscle. Immunocytochemical studies with human fibroblasts and L6 myoblasts revealed intense staining of typical cytoplasmic cables. Myofibrils were not stained after treatment of human and frog skeletal muscle with the antibody, although the distribution of immunofluorescence suggested that cytoplasmic actin is associated with membrane systems in the muscle fiber. The antibody may therefore be especially suited for studying the localization of cytoplasmic actin in skeletal muscle cells even in the presence of a great excess of the myofibrillar form.

scholarly journals Immunological characterization of an anti-actin antibody specific for cytoplasmic actins and its use for the immunocytological localization of actin in Aplysia nervous tissue.

1983 ◽  
Vol 31 (6) ◽  
pp. 728-736 ◽  
Author(s):  
B W Lubit ◽  
J H Schwartz
Keyword(s):  
Nervous Tissue ◽  
Body Wall ◽  
Aplysia Californica ◽  
Amino Acid Sequences ◽  
Marine Mollusc ◽  
Aplysia Neurons ◽  
Cytoplasmic Actin ◽  
Immunofluorescence Studies ◽  
Immunocytochemical Studies

Previous immunochemical and immunocytochemical studies have shown that an antibody to actin prepared from body wall muscle of the marine mollusc Aplysia californica is specific for vertebrate cytoplasmic actins. The ability of this anti-actin to distinguish between different forms of actin most likely reflects the recognition of amino acid sequences unique to cytoplasmic actins. We have confirmed the specificity of this antibody for cytoplasmic actins using nervous tissue as a source of cytoplasmic actin in further immunochemical studies. In addition to binding cytoplasmic actin in purified preparations, the antibody removed actin selectively from crude extracts of nervous tissue of some but not all of the species tested. Our results also suggest that tissue-specific differences in the distribution of cytoplasmic actins may exist. Immunofluorescence studies of Aplysia nervous tissue stained with anti-actin revealed that actin is present in the cell body and axonal processes of Aplysia neurons. Although the function of actin in nerve cells is not understood, the observed pattern of immunofluorescence staining is consistent with the idea that actin may be involved in movement within the axoplasm.

scholarly journals Cytoplasmic actin in postsynaptic structures at the neuromuscular junction.

1981 ◽  
Vol 90 (3) ◽  
pp. 789-792 ◽  
Author(s):  
Z W Hall ◽  
B W Lubit ◽  
J H Schwartz
Keyword(s):  
Neuromuscular Junction ◽  
Mammalian Cells ◽  
Acetylcholine Receptors ◽  
Body Wall ◽  
Neuromuscular Junctions ◽  
Muscle Fibers ◽  
Adult Rat ◽  
Rat Muscle ◽  
Cytoplasmic Actin ◽  
Immunocytochemical Studies

We used an antibody prepared against Aplysia (mollusc) body-wall actin that specifically reacts with certain forms of cytoplasmic actin in mammalian cells to probe for the presence of actin at the neuromuscular junction. Immunocytochemical studies showed that actin or an actinlike molecule is concentrated at neuromuscular junctions of normal and denervated adult rat muscle fibers. Actin is present at the neuromuscular junctions of fibers of developing diaphragm muscles as early as embryonic day 18, well before postsynaptic folds are formed. These results suggest that cytoplasmic actin may play a role in the clustering or stabilization of acetylcholine receptors at the neuromuscular junction.

Kinematic models of the buccal mass of Aplysia californica.

1998 ◽  
Vol 201 (10) ◽  
pp. 1563-1583 ◽  
Author(s):  
R F Drushel ◽  
D M Neustadter ◽  
I Hurwitz ◽  
P E Crago ◽  
H J Chiel
Keyword(s):  
Neural Control ◽  
Kinematic Model ◽  
Aplysia Californica ◽  
Relative Location ◽  
Marine Mollusc ◽  
Buccal Mass ◽  
Kinematic Models ◽  
Made In

The feeding behavior of the marine mollusc Aplysia californica is an intensively studied model system for understanding the neural control of behavior. Feeding movements are generated by contractions of the muscles of the buccal mass. These muscles are internal and cannot be visualized during behavior. In order to infer the movements of the muscles of the buccal mass, two kinematic models were constructed. The first kinematic model assumed that the complex consisting of the pincer-like radula and the underlying odontophore was spherical in shape. In this model, the radula/odontophore was moved anteriorly or posteriorly and the more superficial buccal muscles (I1/I3 and I2) were fitted around it. Although the overall buccal mass shapes predicted by this model were similar to those observed in vivo during protraction, the shapes predicted during retraction were very different. We therefore constructed a second kinematic model in which the shape of the radula/odontophore was based on the shapes assumed by those structures in vitro when they were passively forced into protraction, rest or retraction positions. As each of these shapes was rotated, the second kinematic model generated overall shapes of the buccal mass that were similar to those observed in vivo during swallowing and tearing, and made predictions about the antero-posterior length of the buccal mass and the relative location of the lateral groove. These predictions were consistent with observations made in vivo and in vitro. The kinematic patterns of intrinsic buccal muscles I1 and I2 in vivo were estimated using the second model. Both models make testable predictions with regard to the functions and neural control of intrinsic buccal muscles I2 and I3.

scholarly journals Progressive Structural Defects in Canine Centronuclear Myopathy Indicate a Role for HACD1 in Maintaining Skeletal Muscle Membrane Systems

2017 ◽  
Vol 187 (2) ◽  
pp. 441-456 ◽  
Author(s):  
Gemma L. Walmsley ◽  
Stéphane Blot ◽  
Kerrie Venner ◽  
Caroline Sewry ◽  
Jocelyn Laporte ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Structural Defects ◽  
Muscle Membrane ◽  
Centronuclear Myopathy ◽  
Membrane Systems

scholarly journals Skeletal Muscle and the Maintenance of Vitamin D Status

Nutrients ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3270
Author(s):  
Mark S. Rybchyn ◽  
Myriam Abboud ◽  
David A. Puglisi ◽  
Clare Gordon-Thomson ◽  
Tara C. Brennan-Speranza ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Vitamin D ◽  
Uv Light ◽  
Specific Binding ◽  
Extracellular Fluid ◽  
Muscle Cells ◽  
Vitamin D Status ◽  
Hydroxyvitamin D ◽  
Cytoplasmic Actin ◽  
Specific Binding Sites

Vitamin D, unlike the micronutrients, vitamins A, E, and K, is largely obtained not from food, but by the action of solar ultraviolet (UV) light on its precursor, 7-dehydrocholesterol, in skin. With the decline in UV light intensity in winter, most skin production of vitamin D occurs in summer. Since no defined storage organ or tissue has been found for vitamin D, it has been assumed that an adequate vitamin D status in winter can only be maintained by oral supplementation. Skeletal muscle cells have now been shown to incorporate the vitamin D-binding protein (DBP) from blood into the cell cytoplasm where it binds to cytoplasmic actin. This intracellular DBP provides an array of specific binding sites for 25-hydroxyvitamin D (25(OH)D), which diffuses into the cell from the extracellular fluid. When intracellular DBP undergoes proteolytic breakdown, the bound 25(OH)D is then released and diffuses back into the blood. This uptake and release of 25(OH)D by muscle accounts for the very long half-life of this metabolite in the circulation. Since 25(OH)D concentration in the blood declines in winter, its cycling in and out of muscle cells appears to be upregulated. Parathyroid hormone is the most likely factor enhancing the repeated cycling of 25(OH)D between skeletal muscle and blood. This mechanism appears to have evolved to maintain an adequate vitamin D status in winter.

scholarly journals In vitro and in vivo analysis of human fibroblast reprogramming and multipotency

2015 ◽  
Vol 20 (3) ◽  
Author(s):  
Rongqing Pang ◽  
Xiangqing Zhu ◽  
Jia Geng ◽  
Yongyun Zhang ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Fibroblasts ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Therapeutic Effects ◽  
Tail Vein ◽  
Tail Vein Injection ◽  
Activity Measurements ◽  
Human Dystrophin

AbstractMultipotent stem cells have potential therapeutic roles in the treatment of Duchenne muscular dystrophy (DMD). However, the limited access to stem cell sources restricts their clinical application. To address this issue, we established a simple in vitro epigenetic reprogramming technique in which skin fibroblasts are induced to dedifferentiate into multipotent cells. In this study, human fibroblasts were isolated from circumcised adult foreskin and were reprogrammed by co-culture for 72 h with fish oocyte extract (FOE) in serum-free medium. The cells were then observed and analyzed by immunofluorescence staining, flow cytometry and in vitro differentiation assays. Then FOE-treated human fibroblasts were transplanted by tail vein injection into irradiated mdx mice, an animal model of DMD. Two months after injection, the therapeutic effects of FOE-treated fibroblasts on mdx skeletal muscle were evaluated by serum creatine kinase (CK) activity measurements and by immunostaining and RT-PCR of human dystrophin expression. The results indicated that the reprogrammed fibroblasts expressed higher levels of the pluripotent antigen markers SSEA-4, Nanog and Oct-4, and were able to differentiate in vitro into adipogenic cells, osteoblastic cells, and myotube-like cells. Tail vein injection of FOE-treated fibroblasts into irradiated mdx mice slightly reduced serum CK activity and the percentage of centrally nucleated myofibers two months after cell transplantation. Furthermore, we confirmed human dystrophin protein and mRNA expression in mdx mouse skeletal muscle. These data demonstrated that FOE-treated fibroblasts were multipotent and could integrate into mdx mouse myofibers through the vasculature.

scholarly journals MyoD-positive epiblast cells regulate skeletal muscle differentiation in the embryo

2006 ◽  
Vol 175 (2) ◽  
pp. 283-292 ◽  
Author(s):  
Jacquelyn Gerhart ◽  
Justin Elder ◽  
Christine Neely ◽  
Jared Schure ◽  
Tage Kvist ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Stem Cells ◽  
Body Wall ◽  
Muscle Differentiation ◽  
Skeletal Muscle Differentiation ◽  
Muscle Stem Cells ◽  
Skeletal Muscle Stem Cells

MyoD mRNA is expressed in a subpopulation of cells within the embryonic epiblast. Most of these cells are incorporated into somites and synthesize Noggin. Ablation of MyoD-positive cells in the epiblast subsequently results in the herniation of organs through the ventral body wall, a decrease in the expression of Noggin, MyoD, Myf5, and myosin in the somites and limbs, and an increase in Pax-3–positive myogenic precursors. The addition of Noggin lateral to the somites compensates for the loss of MyoD-positive epiblast cells. Skeletal muscle stem cells that arise in the epiblast are utilized in the somites to promote muscle differentiation by serving as a source of Noggin.

scholarly journals Bridging structures spanning the junctioning gap at the triad of skeletal muscle.

1979 ◽  
Vol 80 (3) ◽  
pp. 743-750 ◽  
Author(s):  
A V Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Surface Membrane ◽  
Membrane Systems ◽  
Close Coupling ◽  
Thin Sections ◽  
Luminal Membrane ◽  
Terminal Cisterna ◽  
Terminal Cisternae ◽  
Junctional Sarcoplasmic Reticulum

The membrane systems of skeletal muscle were examined after tannic acid fixation. A new structure consisting of bridges spanning the junctional gap is described, and a model is proposed in which the cytoplasmic but not the luminal membrane leaflets of the transverse tubule and of the junctional sarcoplasmic reticulum (SR) are continuous. The globular particles (presumably the Ca-binding proteins) within the terminal cisternae were arranged in longitudinal rows and appeared adherent to the junctional membrane. The junctional gap was present in negatively stained, frozen thin sections of fixed muscles. Negatively staining material occured within the junctional gap. The cytoplasmic leaflets of the longitudinal, intermediate, and terminal cisterna regions of the SR exhibited a thick coat of densely staining material compatible with the presence of the Ca-ATPase. Similar bridges were also observed at the surface membrane-SR close coupling sites of vascular smooth muscle.

Sign in / Sign up

Export Citation Format

Share Document