The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.
The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .
A giant elastic protein of molecular mass ranging from 2,993 kDa (cardiac), 3,300 kDa (psoas), to 3,700 kDa (soleus) having a kinase domain. The amino- terminal is involved in a Z line binding, and the carboxy-terminal region is bound to the myosin filament with an overlap between the counter-connectin filaments at the M line.
A powerful flexor of the thigh at the hip joint (psoas major) and a weak flexor of the trunk and lumbar spinal column (psoas minor). Psoas is derived from the Greek "psoa", the plural meaning "muscles of the loin". It is a common site of infection manifesting as abscess (PSOAS ABSCESS). The psoas muscles and their fibers are also used frequently in experiments in muscle physiology.
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
Contractile tissue that produces movement in animals.
A protein factor that regulates the length of R-actin. It is chemically similar, but immunochemically distinguishable from actin.
One of two types of muscle in the body, characterized by the array of bands observed under microscope. Striated muscles can be divided into two subtypes: the CARDIAC MUSCLE and the SKELETAL MUSCLE.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.
An actin capping protein that binds to the pointed-end of ACTIN. It functions in the presence of TROPOMYOSIN to inhibit microfilament elongation.
A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
Fibers composed of MICROFILAMENT PROTEINS, which are predominately ACTIN. They are the smallest of the cytoskeletal filaments.
Muscle contraction with negligible change in the force of contraction but shortening of the distance between the origin and insertion.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Developmental events leading to the formation of adult muscular system, which includes differentiation of the various types of muscle cell precursors, migration of myoblasts, activation of myogenesis and development of muscle anchorage.
Muscular contractions characterized by increase in tension without change in length.
A species of the family Ranidae occurring in a wide variety of habitats from within the Arctic Circle to South Africa, Australia, etc.
Resistance and recovery from distortion of shape.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
The properties, processes, and behavior of biological systems under the action of mechanical forces.
An intermediate filament protein found predominantly in smooth, skeletal, and cardiac muscle cells. Localized at the Z line. MW 50,000 to 55,000 is species dependent.
Contractile activity of the MYOCARDIUM.
A protein found in the thin filaments of muscle fibers. It inhibits contraction of the muscle unless its position is modified by TROPONIN.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.
The hollow, muscular organ that maintains the circulation of the blood.
A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.
An order of the class Amphibia, which includes several families of frogs and toads. They are characterized by well developed hind limbs adapted for jumping, fused head and trunk and webbed toes. The term "toad" is ambiguous and is properly applied only to the family Bufonidae.
The performance of dissections, injections, surgery, etc., by the use of micromanipulators (attachments to a microscope) that manipulate tiny instruments.
Acquired, familial, and congenital disorders of SKELETAL MUSCLE and SMOOTH MUSCLE.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The larger subunits of MYOSINS. The heavy chains have a molecular weight of about 230 kDa and each heavy chain is usually associated with a dissimilar pair of MYOSIN LIGHT CHAINS. The heavy chains possess actin-binding and ATPase activity.
The use of wings or wing-like appendages to remain aloft and move through the air.
A large class of structurally-related proteins that contain one or more LIM zinc finger domains. Many of the proteins in this class are involved in intracellular signaling processes and mediate their effects via LIM domain protein-protein interactions. The name LIM is derived from the first three proteins in which the motif was found: LIN-11, Isl1 and Mec-3.
The restriction of the MOVEMENT of whole or part of the body by physical means (RESTRAINT, PHYSICAL) or chemically by ANALGESIA, or the use of TRANQUILIZING AGENTS or NEUROMUSCULAR NONDEPOLARIZING AGENTS. It includes experimental protocols used to evaluate the physiologic effects of immobility.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal (MUSCLE FIBERS, SKELETAL), cardiac (MYOCYTES, CARDIAC), and smooth (MYOCYTES, SMOOTH MUSCLE). They are derived from embryonic (precursor) muscle cells called MYOBLASTS.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Sharp instruments used for puncturing or suturing.
The use of instrumentation and techniques for visualizing material and details that cannot be seen by the unaided eye. It is usually done by enlarging images, transmitted by light or electron beams, with optical or magnetic lenses that magnify the entire image field. With scanning microscopy, images are generated by collecting output from the specimen in a point-by-point fashion, on a magnified scale, as it is scanned by a narrow beam of light or electrons, a laser, a conductive probe, or a topographical probe.
Bundles of actin filaments (ACTIN CYTOSKELETON) and myosin-II that span across the cell attaching to the cell membrane at FOCAL ADHESIONS and to the network of INTERMEDIATE FILAMENTS that surrounds the nucleus.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Skeletal muscle structures that function as the MECHANORECEPTORS responsible for the stretch or myotactic reflex (REFLEX, STRETCH). They are composed of a bundle of encapsulated SKELETAL MUSCLE FIBERS, i.e., the intrafusal fibers (nuclear bag 1 fibers, nuclear bag 2 fibers, and nuclear chain fibers) innervated by SENSORY NEURONS.
A form of interference microscopy in which variations of the refracting index in the object are converted into variations of intensity in the image. This is achieved by the action of a phase plate.
The excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Elements of limited time intervals, contributing to particular results or situations.
The physical characteristics and processes of biological systems.
Monomeric subunits of primarily globular ACTIN and found in the cytoplasmic matrix of almost all cells. They are often associated with microtubules and may play a role in cytoskeletal function and/or mediate movement of the cell or the organelles within the cell.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
That phase of a muscle twitch during which a muscle returns to a resting position.
Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.
Refers to animals in the period of time just after birth.
A network of tubules and sacs in the cytoplasm of SKELETAL MUSCLE FIBERS that assist with muscle contraction and relaxation by releasing and storing calcium ions.
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching.
Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.

Subcellular adaptation of the human diaphragm in chronic obstructive pulmonary disease. (1/1432)

Pulmonary hyperinflation impairs the function of the diaphragm in patients with chronic obstructive pulmonary disease (COPD). However, it has been recently demonstrated that the muscle can counterbalance this deleterious effect, remodelling its structure (i.e. changing the proportion of different types of fibres). The aim of this study was to investigate whether the functional impairment present in COPD patients can be associated with structural subcellular changes of the diaphragm. Twenty individuals (60+/-9 yrs, 11 COPD patients and 9 subjects with normal spirometry) undergoing thoracotomy were included. Nutritional status and respiratory function were evaluated prior to surgery. Then, small samples of the costal diaphragm were obtained and processed for electron microscopy analysis. COPD patients showed a mean forced expiratory volume in one second (FEV1) of 60+/-9% predicted, a higher concentration of mitochondria (n(mit)) in their diaphragm than controls (0.62+/-0.16 versus 0.46+/-0.16 mitochondrial transections (mt) x microm(-2), p<0.05). On the other hand, subjects with air trapping (residual volume (RV)/total lung capacity (TLC) >37%) disclosed not only a higher n(mit) (0.63+/-0.17 versus 0.43+/-0.07 mt x microm(-2), p<0.05) but shorter sarcomeres (L(sar)) than subjects without this functional abnormality (2.08+/-0.16 to 2.27+/-0.15 microm, p<0.05). Glycogen stores were similar in COPD and controls. The severity of airways obstruction (i.e. FEV1) was associated with n(mit) (r=-0.555, p=0.01), while the amount of air trapping (i.e. RV/TLC) was found to correlate with both n(mit) (r=0.631, p=0.005) and L(sar) (r=-0.526, p<0.05). Finally, maximal inspiratory pressure (PI,max) inversely correlated with n(mit) (r=-0.547, p=0.01). In conclusion, impairment in lung function occurring in patients with chronic obstructive pulmonary disease is associated with subcellular changes in their diaphragm, namely a shortening in the length of sarcomeres and an increase in the concentration of mitochondria. These changes form a part of muscle remodelling, probably contributing to a better functional muscle behaviour.  (+info)

Morphology and mechanics of tongue movement in the African pig-nosed frog Hemisus marmoratum: a muscular hydrostatic model. (2/1432)

The goal of this study was to investigate morphological adaptations associated with hydrostatic elongation of the tongue during feeding in the African pig-nosed frog Hemisus marmoratum. Whereas previous studies had suggested that the tongue of H. marmoratum elongates hydraulically, the anatomical observations reported here favour a muscular hydrostatic mechanism of tongue elongation. H. marmoratum possesses a previously undescribed compartment of the m. genioglossus (m. genioglossus dorsoventralis), which is intrinsic to the tongue and whose muscle fibres are oriented perpendicular to the long axis of the tongue. On the basis of the arrangement and orientation of muscle fibres in the m. genioglossus and m. hyoglossus, we propose a muscular hydrostatic model of tongue movement in which contraction of the m. genioglossus dorsoventralis, together with unfolding of the intrinsic musculature of the tongue, results in a doubling in tongue length. Electron micrographs of sarcomeres from resting and elongated tongues show that no special adaptations of the sarcomeres are necessary to accommodate the observed doubling in tongue length during feeding. Rather, the sarcomeres of the m. genioglossus longitudinalis are strikingly similar to those of anuran limb muscles. The ability to elongate the tongue hydrostatically, conferred by the presence of the m. genioglossus dorsoventralis, is associated with the appearance of several novel aspects of feeding behaviour in H. marmoratum. These include the ability to protract the tongue slowly, thereby increasing capture success, and the ability to aim the tongue in azimuth and elevation relative to the head. Compared with other frogs, the muscular hydrostatic system of H. marmoratum allows more precise, localized and diverse tongue movements. This may explain why the m. genioglossus of H. marmoratum is composed of a larger number of motor units than that of other frogs.  (+info)

Dynamic distribution and formation of a para-sarcomeric banding pattern of prosomes during myogenic differentiation of satellite cells in vitro. (3/1432)

Myogenesis proceeds by fusion of proliferating myoblasts into myotubes under the control of various transcription factors. In adult skeletal muscle, myogenic stem cells are represented by the satellite cells which can be cultured and differentiate in vitro. This system was used to investigate the subcellular distribution of a particular type of prosomes at different steps of the myogenic process. Prosomes constitute the MCP core of the 26S proteasomes but were first observed as subcomplexes of the untranslated mRNPs; recently, their RNase activity was discovered. A monoclonal antibody raised against the p27K subunit showed that the p27K subunit-specific prosomes move transiently into the nucleus prior to the onset of myoblast fusion into myotubes; this represents possibly one of the first signs of myoblast switching into the differentiation pathway. Prior to fusion, the prosomes containing the p27K subunit return to the cytoplasm, where they align with the gradually formed lengthwise-running desmin-type intermediate filaments and the microfilaments, co-localizing finally with the actin bundles. The prosomes progressively form discontinuous punctate structures which eventually develop a pseudo-sarcomeric banding pattern. In myotubes just formed in vitro, the formation of this pattern seems to preceed that produced by the muscle-specific sarcomeric (alpha)-actin. Interestingly, this pattern of prosomes of myotubes in terminal in vitro differentiation was very similar to that of prosomes observed in vivo in foetal and adult muscle. These observations are discussed in relation to molecular myogenesis and prosome/proteasome function.  (+info)

Correlation between myofilament response to Ca2+ and altered dynamics of contraction and relaxation in transgenic cardiac cells that express beta-tropomyosin. (4/1432)

We compared the dynamics of the contraction and relaxation of single myocytes isolated from nontransgenic (NTG) mouse hearts and from transgenic (TG-beta-Tm) mouse hearts that overexpress the skeletal isoform of tropomyosin (Tm). Compared with NTG controls, TG-beta-Tm myocytes showed significantly reduced maximal rates of contraction and relaxation with no change in the extent of shortening. This result indicated that the depression in contraction dynamics determined in TG-beta-Tm isolated hearts is intrinsic to the cells. To further investigate the effect of Tm isoform switching on myofilament activity and regulation, we measured myofilament force and ATPase rate as functions of pCa (-log of [Ca2+]). Compared with controls, force generated by myofilaments from TG-beta-Tm hearts and myofibrillar ATPase activity were both more sensitive to Ca2+. However, the shift in pCa50 (half-maximally activating pCa) caused by changing sarcomere length from 1.8 to 2.4 microm was not significantly different between NTG and TG-beta-Tm fiber preparations. To test directly whether isoform switching affected the economy of contraction, force versus ATPase rate relationships were measured in detergent-extracted fiber bundles. In both NTG and TG-beta-Tm preparations, force and ATPase rate were linear and identically correlated, which indicated that crossbridge turnover was unaffected by Tm isoform switching. However, detergent extracted fibers from TG-beta-Tm demonstrated significantly less maximum tension and ATPase activity than NTG controls. Our results provide the first evidence that the Tm isoform population modulates the dynamics of contraction and relaxation of single myocytes by a mechanism that does not alter the rate-limiting step of crossbridge detachment. Our results also indicate that differences in sarcomere-length dependence of activation between cardiac and skeletal muscle are not likely due to differences in the isoform population of Tm.  (+info)

Myofibrillogenesis in the developing chicken heart: assembly of Z-disk, M-line and the thick filaments. (5/1432)

Myofibrillogenesis in situ was investigated by confocal microscopy of immunofluorescently labelled whole mount preparations of early embryonic chicken heart rudiments. The time-course of incorporation of several components into myofibrils was compared in triple-stained specimens, taken around the time when beating starts. All sarcomeric proteins investigated so far were already expressed before the first contractions and myofibril assembly happened within a few hours. No typical stress fibre-like structures or premyofibrils, structures observed in cultured cardiomyocytes, could be detected during myofibrillogenesis in the heart. Sarcomeric proteins like (&agr;)-actinin, titin and actin were found in a defined localisation pattern even in cardiomyocytes that did not yet contain myofibrils, making up dense body-like structures. As soon as the heart started to beat, all myofibrillar proteins were already located at their exact position in the sarcomere. The maturation of the sarcomeres was characterised by a short delay in the establishment of the pattern for M-line epitopes of titin with respect to Z-disk epitopes and the incorporation of the M-line component myomesin, which preceded that of myosin binding protein-C. Thus dense body-like structures, made up of titin, (&agr;)-actinin and actin filaments serve as the first organised complexes also during myofibrillogenesis in situ and titin functions as a ruler for sarcomere assembly as soon as its C termini have become localised. We suggest that assembly of thin and thick filament occurs independently during myofibrillogenesis in situ and that myomesin might be important for integrating thick filaments with the M-line end of titin.  (+info)

Different domains of the M-band protein myomesin are involved in myosin binding and M-band targeting. (6/1432)

Myomesin is a 185-kDa protein located in the M-band of striated muscle where it interacts with myosin and titin, possibly connecting thick filaments with the third filament system. By using expression of epitope-tagged myomesin fragments in cultured cardiomyocytes and biochemical binding assays, we could demonstrate that the M-band targeting activity and the myosin-binding site are located in different domains of the molecule. An N-terminal immunoglobulin-like domain is sufficient for targeting to the M-band, but solid-phase overlay assays between individual N-terminal domains and the thick filament protein myosin revealed that the unique head domain contains the myosin-binding site. When expressed in cardiomyocytes, the head domains of rat and chicken myomesin showed species-specific differences in their incorporation pattern. The head domain of rat myomesin localized to a central area within the A-band, whereas the head domain of chicken myomesin was diffusely distributed in the cytoplasm. We therefore conclude that the head domain of myomesin binds to myosin but that this affinity is not sufficient for the restriction of the domain to the M-band in vivo. Instead, the neighboring immunoglobulin-like domain is essential for the precise incorporation of myomesin into the M-band, possibly because of interaction with a yet unknown protein of the sarcomere.  (+info)

Effect of rate of distraction on loss of range of joint movement, muscle stiffness, and intramuscular connective tissue content during surgical limb-lengthening: a study in the rabbit. (7/1432)

Surgical lengthening of limbs often results in loss of range of joint movement and this has been shown to be associated with an increase in passive tension and an increase in collagen content of the muscles. In this study, we have investigated the length/tension properties and the connective tissue component of muscle distracted at three different rates in order to determine whether low rates of distraction would enable the connective tissue component, as well as the contractile component (number of serial sarcomeres), to adapt more completely to the increased functional length of the muscle and thus lead to improved range of joint movement. It was found that loss of range of movement varied with rate of distraction. At the low rate, there was no change in the passive tension or collagen content compared to muscles from sham-operated animals, and range of movement was significantly greater than at the other rates. At the medium rate, although the muscles showed good adaptation in terms of serial sarcomere number, passive tension and collagen content was increased and range of movement reduced, indicating that changes in the connective tissue component are important factors in loss of joint movement. In the case of muscle distracted at a high rate, failure of the muscle fibres to add on sufficient sarcomeres, combined with changes in the connective tissue, resulted in almost total loss of joint movement.  (+info)

Cross bridge-dependent activation of contraction in cardiac myofibrils at low pH. (8/1432)

Striated muscle contracts in the absence of calcium at low concentrations of MgATP ([MgATP]), and this has been termed rigor activation because rigor cross bridges attach and activate adjacent actin sites. This process is well characterized in skeletal muscle but not in cardiac muscle. Rigor cross bridges are also thought to increase calcium binding to troponin C and play a synergistic role in activation. We tested the hypothesis that cross bridge-dependent activation results in an increase in contractile activity at normal and low pH values. Myofibrillar ATPase activity was measured as a function of pCa and [MgATP] at pH 7.0, and the data showed that, at pCa values of >/=5.5, there was a biphasic relationship between activity and [MgATP]. Peak activity occurred at 10-50 microM MgATP, and [MgATP] for peak activity was lower with increased pCa. The ATPase activity of rat cardiac myofibrils as a function of [MgATP] at a pCa of 9.0 was measured at several pH levels (pH 5.4-7.0). The ATPase activity as a function of [MgATP] was biphasic with a maximum at 8-10 microM MgATP. Lower pH did not result in a substantial decrease in myofibrillar ATPase activity even at pH 5.4. The extent of shortening, as measured by Z-line spacing, was greatest at 8 microM MgATP and less at both lower and higher [MgATP], and this response was observed at all pH levels. These studies suggest that the peak ATPase activity associated with low [MgATP] was coupled to sarcomere shortening. These results support the hypothesis that cross bridge-dependent activation of contraction may be responsible for contracture in the ischemic heart.  (+info)

1. Muscular dystrophy: A group of genetic disorders characterized by progressive muscle weakness and degeneration.
2. Myopathy: A condition where the muscles become damaged or diseased, leading to muscle weakness and wasting.
3. Fibromyalgia: A chronic condition characterized by widespread pain, fatigue, and muscle stiffness.
4. Rhabdomyolysis: A condition where the muscle tissue is damaged, leading to the release of myoglobin into the bloodstream and potentially causing kidney damage.
5. Polymyositis/dermatomyositis: Inflammatory conditions that affect the muscles and skin.
6. Muscle strain: A common injury caused by overstretching or tearing of muscle fibers.
7. Cervical dystonia: A movement disorder characterized by involuntary contractions of the neck muscles.
8. Myasthenia gravis: An autoimmune disorder that affects the nerve-muscle connection, leading to muscle weakness and fatigue.
9. Oculopharyngeal myopathy: A condition characterized by weakness of the muscles used for swallowing and eye movements.
10. Inclusion body myositis: An inflammatory condition that affects the muscles, leading to progressive muscle weakness and wasting.

These are just a few examples of the many different types of muscular diseases that can affect individuals. Each condition has its unique set of symptoms, causes, and treatment options. It's important for individuals experiencing muscle weakness or wasting to seek medical attention to receive an accurate diagnosis and appropriate care.

Kreis, Thomas E.; Birchmeier, Walter (November 1980). "Stress fiber sarcomeres of fibroblasts are contractile". Cell. 22 (2): ... fibers in the ventral regions of non-motile cells show a periodic polarity that is similar to the organization of the sarcomere ...
PMID 23201505.{{cite journal}}: CS1 maint: uses authors parameter (link) Scott AB (1994). "Change of eye muscle sarcomeres ... so that a paralyzed muscle tends to get stretched-out by its antagonist and grows longer by addition of serial sarcomeres (the ... contractile units of skeletal muscles), while the antagonist tends to grow shorter by deletion of sarcomeres,[unreliable ...
... appears to be necessary for the proper incorporation of myosin filaments into sarcomeres and in the assembly of A- ... Titin, obscurin, obscurin-like-1 and myomesin form a ternary complex at sarcomeric M-bands that is critical for sarcomere ... Obscurin is expressed in cardiac and skeletal muscle, and plays a role in the organization of myofibrils during sarcomere ... Borisov AB, Martynova MG, Russell MW (Apr 2008). "Early incorporation of obscurin into nascent sarcomeres: implication for ...
Scott, A. B. (March 6, 1994). "Change of eye muscle sarcomeres according to eye position". Journal of Pediatric Ophthalmology ...
leading to breakdown of the sarcomere. This was found to be due to regulation of gene expression of Trim63/MuRF1 by the FOXO ( ... where titin's N-terminal and C-terminal regions respectively bind to the sarcomere. In vitro binding studies have shown that ... which is a major component of the sarcomere, is an important mechanism in the breakdown of skeletal muscle under atrophy ...
They run through the core of each thick filament and anchor it to the Z-line, the end point of a sarcomere.[citation needed] ... The muscle fiber relaxes and the entire sarcomere lengthens. The muscle fiber is now prepared for the next contraction. The ... Muscle contraction consists of the simultaneous shortening of multiple sarcomeres. The axon terminal of a motor neuron releases ... Thus muscle contraction occurs, and the sarcomere shortens as this process takes place. The enzyme acetylcholinesterase breaks ...
These sarcomeres are arranged in adjacent formations along the myofibrils. Similarly to the plasma membrane of other cells, the ... The Z-line defines the borders of each sarcomere and act as the connection point between the thin filaments. The t-tubules and ... A myocyte is composed of multiple myofibrils, which contain the "contractile units" of the muscle known as a sarcomere. ... These structures attached to the sarcomere z-lines help to promote interaction between the extracellular space and the interior ...
In addition to sarcomere activity, it has been shown that myomesin also plays a role in the assembly of the sarcomere. In order ... Myomesin plays an important role in the structure of sarcomeres. They are found in the M-band region of the sarcomere, between ... This is extremely important as if even one piece of the M-line is missing, the A-band of the sarcomere will collapse and the ... Since the Z-disc region of the sarcomere is very stiff and unable to bend for contraction, the elastic activity of myomesin in ...
The costamere is a structural-functional component of striated muscle cells which connects the sarcomere of the muscle to the ... They physically couple force-generating sarcomeres with the sarcolemma in striated muscle cells and are thus considered one of ... They are also responsible for the lateral transmission of the sarcomere-generated contractile force to the sarcolemma and the ... Restated, filamin C physically links the two complexes that constitute the costamere to sarcomeres by interacting with the ...
In addition to sarcomeres, PKCε also targets cardiac mitochondria. Proteomic analysis of PKCε signaling complexes in mice ... PKCε translocates to cardiac muscle sarcomeres and modulates contractility of the myocardium. PKCε binds RACK2 at Z-lines with ... A role for focal adhesion kinase at costameres in strain-sensing and modulation of sarcomere length has been linked to ... PKCε translocation to sarcomeres and phosphorylation of cTnI and cMyBPC is involved in the κ-opioid- and α-adrenergic-dependent ...
At the sarcomere, ARPP binds titin at I-bands, which is potentiated by homo-dimerization and can alter the protein kinase A/ ... ARPP localizes to both nuclei and sarcomeres in muscle cells. ARPP may play a role in the differentiation of myocytes, as ARPP ... with longer resting sarcomere length, decreased fiber stiffness, expression of a longer titin isoform, greater degree of torque ... a link between the sarcomere and the nucleus in skeletal muscle". J. Mol. Biol. 339 (2): 313-25. doi:10.1016/j.jmb.2004.03.071 ...
HCM is described as a disease of the sarcomere, because mutations in the contractile proteins of the sarcomere have been ... The calcium sensitivity of the sarcomere, that is, the calcium concentration at which muscle contraction occurs, is directly ... Hwang PM, Sykes BD (Apr 2015). "Targeting the sarcomere to correct muscle function". Nature Reviews. Drug Discovery. 14 (5): ...
"Sliding Filament Theory, Sarcomere, Muscle Contraction, Myosin , Learn Science at Scitable". www.nature.com. Retrieved 2018-09- ...
... found in the sarcomere MYL5 (chromosome 4p16.3); found in the sarcomere MYL7 (chromosome 12q13.2); found in the sarcomere MYL9 ...
Chapin, LM; Blankman, E; Smith, MA; Shiu, YT; Beckerle, MC (2012). "Lateral communication between stress fiber sarcomeres ...
Nicol RL, Frey N, Pearson G, Cobb M, Richardson J, Olson EN (Jun 2001). "Activated MEK5 induces serial assembly of sarcomeres ...
They occur at the Z line of the sarcomere and can be visualized easily when observing a longitudinal section of the tissue. ... Fascia adherens are anchoring sites for actin, and connect to the closest sarcomere. Desmosomes prevent separation during ... Hyperdistended myocardiocytes with detached sarcomeres, and in proximity of hypercontracted myocardiocytes. Square-shaped ...
Niimura H, Patton KK, McKenna WJ, Soults J, Maron BJ, Seidman JG, Seidman CE (Jan 2002). "Sarcomere protein gene mutations in ... Niimura H, Patton KK, McKenna WJ, Soults J, Maron BJ, Seidman JG, Seidman CE (Jan 2002). "Sarcomere protein gene mutations in ... This enables proper assembly of myofibrils and thus, more organized sarcomeres. All of the mice in the study developed HCM ... This process converts chemical to mechanical energy, and propels shortening of the sarcomeres in order to generate ...
DOI:10.1016/S0006-3495(93)81482-6 Wang, K.; Wright, J. (1988). "Architecture of the sarcomere matrix of skeletal muscle: ... "Viscoelasticity of the sarcomere matrix of skeletal muscles. The titin-myosin composite filament is a dual-stage molecular ... which fundamentally changed our understanding of muscle sarcomeres. At UT Wang was promoted to associate professor in 1984 and ... extended and ramified their findings on the structures of Titin and Nebulin and how they function within the sarcomere. In 1997 ...
"G9a inhibits MEF2C activity to control sarcomere assembly". Scientific Reports. 6 (1): 34163. Bibcode:2016NatSR...634163O. doi: ...
Gupta MP, Samant SA, Smith SH, Shroff SG (April 2008). "HDAC4 and PCAF bind to cardiac sarcomeres and play a role in regulating ... Luther PK (2009). "The vertebrate muscle Z-disc: sarcomere anchor for structure and signalling". Journal of Muscle Research and ... "Beyond the sarcomere: CSRP3 mutations cause hypertrophic cardiomyopathy". Human Molecular Genetics. 17 (18): 2753-65. doi: ... different Z-line components and acts as a scaffold protein promoting the assembly of macromolecular complexes along sarcomeres ...
The sarcomere is attached to other organelles such as the mitochondria by intermediate filaments in the cytoskeleton. The ... At the muscle-tendon interface, force is transmitted from the sarcomeres in the muscle cells to the tendon. Muscles and tendons ... In addition to the actin and myosin myofilaments in the myofibrils that make up the contractile sarcomeres, there are two other ... The muscle tissue of a skeletal muscle is striated - having a striped appearance due to the arrangement of the sarcomeres. ...
The sarcomeres become misaligned and result in the disorganization of muscle fibers. This mutation also results in muscle cell ...
Sarcomeres are added in parallel, as for example occurs in hypertrophic cardiomyopathy.[citation needed] In the heart, ...
The pacemaker cells are only weakly contractile without sarcomeres, and are connected to neighboring contractile cells via gap ... The regular organization of myofibrils into sarcomeres gives cardiac muscle cells a striped or striated appearance when looked ... Cardiomyocyte hypertrophy occurs through sarcomerogenesis, the creation of new sarcomere units in the cell. During heart volume ... These are organized into sarcomeres, the fundamental contractile units of muscle cells. ...
Alpha cardiac actin is the major protein of the thin filament in cardiac sarcomeres, which are responsible for muscle ... at Z-lines towards the center of the sarcomere. Polymerization of globular actin (G-actin) leads to a structural filament (F- ... "Mutations in sarcomere protein genes in left ventricular noncompaction". Circulation. 117 (22): 2893-901. doi:10.1161/ ...
The power stroke moves the actin filament inwards, thereby shortening the sarcomere. Myosin then releases ADP but still remains ... This fine myofilament maintains uniform tension across the sarcomere by pulling the thick filament into a central position. ... Gordon AM, Huxley AF, Julian FJ (1966). "The variation in isometric tension with sarcomere length in vertebrate muscle fibres ... Physiologically, this contraction is not uniform across the sarcomere; the central position of the thick filaments becomes ...
Affected mice have disrupted z-band and sarcomere morphology. In this experimental model ryanodine and IP3 receptors have ... Hammarlund, M; Davis WS; Jorgensen EM (2000). "Mutations in β-Spectrin Disrupt Axon Outgrowth and Sarcomere Structure". Journal ...
Fiber length is the product of both the number of sarcomeres in series in the fiber and their individual lengths. As a fiber ... The force produced by a given muscle is proportional to the cross-sectional area, or the number of parallel sarcomeres present ... Because of this structure, fewer sarcomeres can be found in series, resulting in a shorter fiber length. This further allows ... Velocity is affected in the reverse manner - because sarcomeres shorten at a certain percentage per second under a certain ...
NM-IIB may play a role in formation of mature sarcomeres in myofibrils. It appears that NM-IIB plays an essential role in ...
Targeting the sarcomere to correct muscle function Peter M Hwang et al. Nat Rev Drug Discov. 2015 May. ... Targeting the sarcomere to correct muscle function Peter M Hwang 1 , Brian D Sykes 2 ... Here, we review agents that modulate the mechanical function of the sarcomere, focusing on emerging compounds that target ...
Lengths of sarcomeres in series within a fiber vary substantially. ... Microendoscopy can be used to measure sarcomere lengths at different body postures. ... Lengths of sarcomeres in series were measured in a region of interest from each frame. (a) Image of human sarcomeres. Scale bar ... sarcomere inhomogeneity; sarcomere length variability; sarcomere operating length; second-harmonic generation microendoscopy; ...
describe two actin-nucleating proteins that assemble actin filaments into the sarcomeres of worm muscle cells. ... Pruyne now wants to investigate how the formins are recruited to developing sarcomeres and to determine how their activity is ... Senior author David Pruyne says its unclear why nematodes need two formins to build muscle sarcomeres; one possibility is that ... FHOD-1 localized around each sarcomeres Z lines, the sites where actin filaments are anchored. Worms lacking FHOD-1 had ...
3) Smyd1b_tv1, but not Smyd1b_tv2 can be localized on the M-line of sarcomeres. 4) Ser225 on Smyd1b_tv1, which is a potential ... this study provides new insights to help us understand the complex process of myofibrillogenesis and sarcomere diseases. ... Myofibrillogenesis is a process of precise assembly of sarcomeric proteins into the highly organized sarcomeres which are ... 3) Smyd1b_tv1, but not Smyd1b_tv2 can be localized on the M-line of sarcomeres. 4) Ser225 on Smyd1b_tv1, which is a potential ...
Sarcomere Protein Expression Studies Suggest Mutation-Specific Disease Mechanisms in Human Hypertrophic Cardiomyopathy. POSTED ...
Laser diffraction (LD)-based measurements of sarcomere length are time-efficient and sample a greater number of sarcomeres ... Laser diffraction (LD)-based measurements of sarcomere length are time-efficient and sample a greater number of sarcomeres ... Laser diffraction (LD)-based measurements of sarcomere length are time-efficient and sample a greater number of sarcomeres ... Laser diffraction (LD)-based measurements of sarcomere length are time-efficient and sample a greater number of sarcomeres ...
Break some sarcomeres. Repeat.Hit the beach, the street or the gym in this soft, durable tank from the Spreadshirt Collection. ... Break some sarcomeres. Repeat.. Hit the beach, the street or the gym in this soft, durable tank from the Spreadshirt Collection ...
Get editable icons and illustrations of Sarcomere (myosin). Create professional science figures in minutes with BioRender ... sarcomere,muscle,striated muscle,skeletal muscle,myosin,thick filament,motor protein,myosin molecule ... ":"https://icons.biorender.com/w550xh620/5cefe1a1da626304005ad983/sarcomere-myosin.png"},{"image":"https://icons.biorender.com/ ... w75xh75/5cefe1a1da626304005ad982/sarcomere-myosin.png","waterMarkImage":"https://icons.biorender.com/w550xh620/ ...
Each sarcomere element consists of a contractile sarcomere in parallel with a Voigt body. The Voigt body is defined as a linear ... The contractile sarcomere force generation is governed by the response of a 4 state model of troponin in the sarcomere to an ... A two element model incorporating two 4-state sarcomeres in series. This model is based on the 4 state model of a cardiac ... Note that the convention used by Landesberg and Sideman for positive velocity is when the sarcomere is contracting. Therefore ...
Interaction Between Series Compliance and Sarcomere Kinetics Determines Internal Sarcomere Shortening During Fixed-End ... Heterogeneity of Mean Sarcomere Length in Different Fibres: Effects on Length Range of Active Force Production in Rat Muscle ... Finite-element modeling showed that the distribution of lengths of sarcomeres is altered by changes of muscle-relative position ... The Relative Position of EDL Muscle Affects the Length of Sarcomeres Within Muscle Fibers: Experimental Results and Finite- ...
Home,Publications,General Physiology,Computing Average Passive Forces in Sarcomeres in Length-Ramp Simulations . ... Computing Average Passive Forces in Sarcomeres in Length-Ramp Simulations . *Author(s): Schappacher-Tilp, Gudrun et al. ... Computing Average Passive Forces in Sarcomeres in Length-Ramp Simulations .aursc20dev2021-07-23T13:09:04-04:00 ...
Last, increasing myocyte preload (sarcomere length) increased %DRX 1.5-fold in controls but only 1.2-fold in both HFrEF-PH ... Right Ventricular Sarcomere Contractile Depression and the Role of Thick Filament Activation in Human Heart Failure With ...
Researchers use cryo-electron tomography to reveal novel molecular details of muscle sarcomeres. A group of researchers succeed ... in producing the first ever high resolution image of the sarcomere. ...
... profile, educations, publications, ... Sarcomeres are the tension-generating units of actin stress fibers in endothelial cells. How sarcomeres generate and maintain ... The length of the sarcomere decreased in two phases: an instantaneous initial response, followed by a slower change in length ... The latter phase ceased abruptly after a minimum sarcomere length was reached, suggesting a rigid resistance that prevents ...
Contribution of sarcomere gene mutations to left atrial function in patients with hypertrophic cardiomyopathy *Hyemoon Chung ... Effect of sarcomere and mitochondria-related mutations on myocardial fibrosis in patients with hypertrophic cardiomyopathy * ...
Within muscle cells, titin is an essential component of structures called sarcomeres. . Sarcomeres are the basic units of ... Titin has several functions within sarcomeres. One of its most important jobs is to provide structure, flexibility, and ... Researchers suspect that these changes may disrupt titins interactions with other proteins within sarcomeres. Mutations may ... Titin also plays a role in chemical signaling and in assembling new sarcomeres. ...
Two Photon Microscopy Measurements Of Sub-epicardial Sarcomere Length In Perfused Rat Hearts ... Two Photon Microscopy Measurements Of Sub-epicardial Sarcomere Length In Perfused Rat Hearts ...
This gene encodes a major sarcomeric protein in mammalian striated muscle. The encoded protein plays a role in embryonic heart muscle structure and function, while phosphorylation of the encoded protein is involved in cardiac myosin cycling kinetics, torsion and function in adults. Mutations in this gene are associated with hypertrophic cardiomyopathy 10 and infant-onset myopathy. [provided by RefSeq, May 2022 ...
Microcomputer-Based Image Processing System for Measuring Sarcomere Motion of Single Cardiac Cells」の研究トピックを掘り下げます。これらがまとまってユニー ... Sato T, Watanabe T, Honjo H, Naito Y, Kodama I, Junji T. Microcomputer-Based Image Processing System for Measuring Sarcomere ... Microcomputer-Based Image Processing System for Measuring Sarcomere Motion of Single Cardiac Cells. / Sato, Toshio; Watanabe, ... Microcomputer-Based Image Processing System for Measuring Sarcomere Motion of Single Cardiac Cells.
Title: Sarcomere length influences postmortem proteolysis of excised bovine semitendinosus muscle Author. WEAVER, AMANDA ... Sarcomere length influences postmortem proteolysis of excised bovine semitendinosus muscle. Journal of Animal Science. 86(8): ... Technical Abstract: The interaction between sarcomere length and postmortem proteolysis as related to meat tenderness is not ... The objective of this study was to determine the influence of sarcomere length on proteolytic degradation in beef. Strips from ...
These mitochondria are larger than entire sarcomeres. Normal mitochondria are much smaller than sarcomeres. View Media Gallery ... These mitochondria are larger than entire sarcomeres. Normal mitochondria are much smaller than sarcomeres. ...
Mitochondrial network configuration influences sarcomere and myosin filament structure in striated muscles. Katti P, Hall AS, ...
Sarcomeres regulate murine cardiomyocyte maturation through MRTF-SRF signaling.. Proc. Natl. Acad. Sci. USA. 2021; 118 ...
Viscoelasticity of the sarcomere matrix of skeletal muscles. The titin-myosin composite filament is a dual-stage molecular ... 深入研究「Viscoelasticity of the sarcomere matrix of skeletal muscles. The titin-myosin composite filament is a dual-stage molecular ...
METHODS:Using genome sequencing data from 240 sarcomere gene negative HCM cases and 6229 controls, we undertook case-control ... METHODS:Using genome sequencing data from 240 sarcomere gene negative HCM cases and 6229 controls, we undertook case-control ... Analysis of 51 proposed hypertrophic cardiomyopathy genes from genome sequencing data in sarcomere negative cases has ... Analysis of 51 proposed hypertrophic cardiomyopathy genes from genome sequencing data in sarcomere negative cases has ...
Individual z-disks (various colors) and contractile sarcomeres (magenta) are also shown. ...
J. Kolb, F. Li, M. Methawasin et al., "Thin filament length in the cardiac sarcomere varies with sarcomere length but is ... As a primary component of the sarcomere, actin is necessary for proper sarcomere organization and function; indeed, several ... The sarcomere is not a separate unit inside the muscle fibers, but it is an integral part of the complex arrangement that works ... The sarcomere is tethered to the sarcolemma by a cytoskeletal assembly named costamere. It is a macromolecular protein ...
Sarcomere Model Cross Sectional View. 02:41 , 6962 views Watch VIDEO. 4739 views ...
A single-sarcomere line scan further demonstrated that the differences in polarization-spectrum symmetry between α- and β- ... MeSH Terms: Animals; Cardiac Myosins*; Myocytes, Cardiac; Myosins; Rats; Sarcomeres*; Ventricular Myosins ...
CHD4 and the NuRD complex directly control cardiac sarcomere formation. Proc Natl Acad Sci USA 2018 115 (26): 6727-6732.] ... CHD4 and the NuRD complex directly control cardiac sarcomere formation. Proc Natl Acad Sci USA 2018 115 (26): 6727-6732. [ ...

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