TY - JOUR. T1 - Tropomodulin 1 directly controls thin filament length in both wild-type and tropomodulin 4-deficient skeletal muscle. AU - Gokhin, David S.. AU - Ochala, Julien. AU - Domenighetti, Andrea A.. AU - Fowler, Velia M.. N1 - Publisher Copyright: © 2015. Published by The Company of Biologists Ltd.. PY - 2015/12/15. Y1 - 2015/12/15. N2 - The sarcomeric tropomodulin (Tmod) isoforms Tmod1 and Tmod4 cap thin filament pointed ends and functionally interact with the leiomodin (Lmod) isoforms Lmod2 and Lmod3 to control myofibril organization, thin filament lengths, and actomyosin crossbridge formation in skeletal muscle fibers. Here, we show that Tmod4 is more abundant than Tmod1 at both the transcript and protein level in a variety of muscle types, but the relative abundances of sarcomeric Tmods are muscle specific.We then generate Tmod4−/− mice, which exhibit normal thin filament lengths, myofibril organization, and skeletal muscle contractile function owing to compensatory ...

Mechanisms involved in establishing the organization and numbers of fibres in a muscle are not completely understood. During Drosophila indirect flight muscle (IFM) formation, muscle growth is achieved by both incorporating hundreds of nuclei, and hypertrophy. As a result, IFMs provide a good model with which to understand the mechanisms that govern overall muscle organization and growth. We present a detailed analysis of the organization of dorsal longitudinal muscles (DLMs), a subset of the IFMs. We show that each DLM is similar to a vertebrate fascicle and consists of multiple muscle fibres. However, increased fascicle size does not necessarily change the number of constituent fibres, but does increase the number of myofibrils packed within the fibres. We also find that altering the number of myoblasts available for fusion changes DLM fascicle size and fibres are loosely packed with myofibrils. Additionally, we show that knock down of genes required for mitochondrial fusion causes a severe ...

Chicken heart muscle contains almost exclusively the BB isoenzyme of creatine kinase (CK), its myofibrils, moreover, lack an M-line. This tissue thus provides an interesting contrast to skeletal muscle, in which some of the MM-CK present as predominant CK isoenzyme is bound at the myofibrillar M-line. Approx. 2% of the total CK activity in a chicken heart homogenate remains bound to the myofibrillar fraction after repeated washing cycles; both the fraction and the absolute amount of CK bound are about threefold lower than in skeletal muscle. Almost all of the bound enzyme is located within the Z-line region of each sarcomere, as revealed by indirect fluorescent-antibody staining with antiserum against purified chicken BB-CK. After incubation with exogenous purified MM-CK, positive immunofluorescent staining for M-type CK at the H-region of heart myofibrils was observed, along with weaker fluorescence in the Z-line region. Chicken heart myofibrils may thus possess binding sites for both M and B ...

TY - JOUR. T1 - Dynamic characteristics of F-actin and thin filaments in vivo and in vitro.. AU - Oosawa, F.. AU - Maeda, Y.. AU - Fujime, S.. AU - Ishiwata, S.. AU - Yanagida, T.. AU - Taniguchi, M.. PY - 1977/3. Y1 - 1977/3. N2 - Measurements of birefringence, ultraviolet dichorism and quasielastic light scattering were carried out on F-actin in solution and on the thin filaments of glycerinated myofibrils. The birefringence of the I-bands of myofibrils was of the same order of magnitude as that of F-actin or the F-actin-tropomyosin-troponin complex oriented in vitro at the same concentration. The ultraviolet dichroism spectrum of the I-bands was very similar to that of F-actin or the F-actin complex in vitro, which is due to orientation of bound ADP and tryptophan residues in F-actin. Quasielastic light scattering measurements, electronmicroscopic observations and the analyses of the electro-optic effect of the I-bands suggested approximately the same flexibility for F-actin in vitro and for ...

Myofibrils which lengthen by several per cent in the presence of ATP and magnesium ions were prepared by teasing indirect flight muscle of Drosophila in solutions containing ethylenediaminetetraacetate. A study was made of the hydrogen ion, magnesium ion, ATP, and potassium chloride concentrations with which this effect could be observed. The lack of elongation with pyrophosphate and several nucleoside triphosphates suggests that the lengthening is ATP specific. A relaxing factor system comparable to that described for rabbit muscle was not demonstrable, as elongated fibrils did not shorten with calcium ions, carnosine, or digitonin.. ...

Myofiber growth and myofibril assembly at the myotendinous junction (MTJ) of stretch-hypertrophied rabbit skeletal muscle was studied by in situ hybridization, immunofluorescence, and electron microscopy. In situ hybridization identified higher levels of myosin heavy chain (MHC) mRNA at the MTJ of fibers stretched for 4 d. Electron microscopy at the MTJ of these lengthening fibers revealed a large cytoplasmic space devoid of myofibrils, but containing polysomes, sarcoplasmic reticulum and T-membranes, mitochondria, Golgi complexes, and nascent filament assemblies. Tallies from electron micrographs indicate that myofibril assembly in stretched fibers followed a set sequence of events. (a) In stretched fiber ends almost the entire sarcolemmal membrane was electron dense but only a portion had attached myofibrils. Vinculin, detected by immunofluorescence, was greatly increased at the MTJ membrane of stretched muscles. (b) Thin filaments were anchored to the sarcolemma at the electron dense sites. ...

Introduction. The Structure of Skeletal Muscle Skeletal muscles are all muscles that are attached to the skeleton such as the biceps and the hamstring. Within each muscle cell (also known as a muscle fibre) are structures called myofibrils as shown in the picture below: (Ref. The picture above was found at www.google.com) Myofibrils are made up of tiny units called sarcomeres. Sarcomeres are the smallest structures in a muscle that can contract; they are long filament-like structures, arranged in series - end to end - that run lengthways in the myofibril. Within the sarcomeres are two types of protein filaments that are actin and myosin - running lengthways, parallel to each other. The myosin filaments have cross-bridges across to the actin filaments, which during contraction allow them to bond with the actin filaments. The source of energy for this bonding is the molecule adenosine triphosphate (ATP). During the bonding, energy is released by the breaking down of ATP into adenosine ...

We evaluated cardiac muscle development in the absence of hemodynamic work load but in the presence of host factors including blood vessels, nerves, and circulating neurohumoral agents by transplanting 12-day fetal rat ventricle into the anterior eye chamber of adult host rats. Implants were studied by electron microscopy at intervals from 1 to 14 weeks in oculo. For comparison with myocardium developing in oculo, 12-day fetal tissue and 3-, 8-, and 28-day-old normally growing rats were also studied. At 1 week in oculo, myofibrils were laterally located and more frequent than in the 12-day fetus. Fibrils had clear Z bands and H bands, but no M bands. At 10 days in oculo (comparable to birth in normally growing animals), myocyte mitoses were present and tritiated thymidine autoradiography revealed many labeled myocyte nuclei. By 5 weeks in oculo, cells were filled with mature myofibrils with clear M bands and lateral connections between adjacent Z bands. However, myofibril bundles sometimes ...

Muscles organise pseudo-crystalline arrays of actin, myosin and titin filaments to build force-producing sarcomeres. To study sarcomerogenesis, we have generated a transcriptomics resource of developing flight muscles and identified 40 distinct expression profile clusters. Strikingly, most sarcomeric components group in two clusters, which are strongly induced after all myofibrils have been assembled, indicating a transcriptional transition during myofibrillogenesis. Following myofibril assembly, many short sarcomeres are added to each myofibril. Subsequently, all sarcomeres mature, reaching 1.5 µm diameter and 3.2 µm length and acquiring stretch-sensitivity. The efficient induction of the transcriptional transition during myofibrillogenesis, including the transcriptional boost of sarcomeric components, requires in part the transcriptional regulator Spalt major. As a consequence of Spalt knock-down, sarcomere maturation is defective and fibers fail to gain stretch-sensitivity. Together, this ...

The formation of perfectly aligned myofibrils in cardiac muscle represents a dramatic examine of supramolecular assembly in eukaryotic cells; the mechanisms by which this occurs are still incompletely understood. The long term objective of this research is to identify the molecular components and mechanisms that regulate contractile protein interactions during myofibril assembly. The goal of this proposal is to define the function(s) of tropomodulin, and its specific molecular interactions, in regulation of thin filament assembly and organization using a novel model of de novo cardiac myofibril assembly that faithfully recapitulates myofibril assembly in vivo. My career research development plan, which encompasses the establishment of an interdisciplinary cardiac muscle research program, will include gaining expertise in molecular developmental biology and advanced microscopy techniques (including real-time fluorescence image analysis) by formal course work, interactions with colleagues and ...

Each muscle fiber is made up of a collection of smaller fibers called Myofibrils. Muscle hypertrophy is due to an increase in the number of myofibrils within each fiber. Each myofibril extends the full length of the fiber, and is made up of a longitudinal arrangement of units called sarcomeres. The sarcomere is the structure responsible for the actual contraction. Each sarcomere consists of thick (myosin) and thin (actin) protein filaments that lie adjacent to one another horizontally, but are slightly separated longitudinally. Contraction occurs when the thick filaments attach to the thin filaments (crossbridge) and pull the thin filaments toward the center of the thick filament. The number of sarcomeres in series along a myofibril depends on the length and architecture of the specific muscle. The sartorius, which is the longest muscle in the body, has more than 100,000 sarcomeres in series, while a shorter muscle, such as the soleus, has closer to 10,000 sarcomeres in series. ...

BIOS 252 Week 1 Lab 1 Muscular System Overview Latest. Check this A+ tutorial guideline at. http://www.assignmentclick.com/bios-252/bios-252-week-1-lab-1-muscular-system-overview-latest. For more classes visit. http://www.assignmentclick.com. BIOS 252 Week 1 Lab 1 Muscular System Overview Latest. Click the Skeletal Muscle Cross Section and identify each of the following. Consult your textbook for a description of each. Using your textbook, define an aponeurosis. Describe arm movement (flexion) when filaments are contracted.. Click on the Skeletal Muscle Cell. Muscle fibers contain bundles of myofibrils. Myofibrils are composed of smaller filaments. ...

The purpose of the present study was to describe sarcomere dynamics in thin trabeculae that were dissected from the right ventricle of kittens. The muscles were mounted in an experimental chamber and perfused with a modified Krebs-Henseleit solution (25 degrees C). Sarcomere length (SL) was measured by laser diffraction techniques; force, by a silicon strain gauge; and velocity of sarcomere shortening, by the isovelocity release technique. Contractile activation was varied by changing the calcium concentration in the bathing medium ([Ca2+]o). Slack SL was 1.85 +/- 0.04 microns. When length of the muscle was held constant, the sarcomeres in the central region of the muscle shortened during the twitch by up to 21%. Both peak sarcomere isometric twitch force and unloaded velocity of sarcomere shortening (Vo) were a sigmoidal function of [Ca2+]o. Maximum Vo was 9.8 +/- 0.2 microns/sec; maximum sarcomere isometric twitch force was 108 +/- 13.8 mN/mm2. The shape of the force-SL relation was a ...

This study presents a structure-function analysis of the mammalian left ventricle and examines the performance of the cardiac capillary network, mitochondria, and myofibrils at rest and during simulated heavy exercise. Left ventricular external mechanical work rate was calculated from cardiac output and systemic mean arterial blood pressure in resting sheep (Ovis aries; n = 4) and goats (Capra hircus; n = 4) under mild sedation, followed by perfusion-fixation of the left ventricle and quantification of the cardiac capillary-tissue geometry and cardiomyocyte ultrastructure. The investigation was then extended to heavy exercise by increasing cardiac work according to published hemodynamics of sheep and goats performing sustained treadmill exercise. Left ventricular work rate averaged 0.017 W/cm3 of tissue at rest and was estimated to increase to ∼0.060 W/cm3 during heavy exercise. According to an oxygen transport model we applied to the left ventricular tissue, we predicted that oxygen ...

Q: Thank you for clearing up the muscle-growth mystery for me. I always believed in going heavier and heavier to get bigger. Now I know thats only a small part of the puzzle. Working in the 4X method, X Reps, drop sets, and even some of your high-rep TORQ sets has already gotten me bigger in just a few weeks. My question is, Do you think some people get a better size response from power training and others get more size from density [endurance] work?. A: Absolutely. As we mentioned in a previous newsletter, the BIGGEST powerlifters dont train for sarcoplasmic (endurance fluid) expansion yet have good muscle size. Thats because they were big dudes in the first place, which may signify more myofibril-building capacity. That would explain their extraordinary strength. The myofibrils are the actin-myosin strands inside the muscle fiber that generate force, but for most trainees thats not the key to ULTIMATE SIZE… [Read more…] ...

Myopathy, myofibrillar, 1 (MFM1) [MIM:601419]: A form of myofibrillar myopathy, a group of chronic neuromuscular disorders characterized at ultrastructural level by disintegration of the sarcomeric Z disc and myofibrils, and replacement of the normal myofibrillar markings by small dense granules, or larger hyaline masses, or amorphous material. MFM1 is characterized by skeletal muscle weakness associated with cardiac conduction blocks, arrhythmias, restrictive heart failure, and accumulation of desmin-reactive deposits in cardiac and skeletal muscle cells. {ECO:0000269,PubMed:10545598, ECO:0000269,PubMed:10717012, ECO:0000269,PubMed:10905661, ECO:0000269,PubMed:11061256, ECO:0000269,PubMed:11668632, ECO:0000269,PubMed:12620971, ECO:0000269,PubMed:12766977, ECO:0000269,PubMed:14648196, ECO:0000269,PubMed:14711882, ECO:0000269,PubMed:14724127, ECO:0000269,PubMed:15495235, ECO:0000269,PubMed:15800015, ECO:0000269,PubMed:16009553, ECO:0000269,PubMed:16376610, ECO:0000269,PubMed:16865695, ...

Myopathy, myofibrillar, 1 (MFM1) [MIM:601419]: A form of myofibrillar myopathy, a group of chronic neuromuscular disorders characterized at ultrastructural level by disintegration of the sarcomeric Z disc and myofibrils, and replacement of the normal myofibrillar markings by small dense granules, or larger hyaline masses, or amorphous material. MFM1 is characterized by skeletal muscle weakness associated with cardiac conduction blocks, arrhythmias, restrictive heart failure, and accumulation of desmin-reactive deposits in cardiac and skeletal muscle cells. {ECO:0000269,PubMed:10545598, ECO:0000269,PubMed:10717012, ECO:0000269,PubMed:10905661, ECO:0000269,PubMed:11061256, ECO:0000269,PubMed:11668632, ECO:0000269,PubMed:12620971, ECO:0000269,PubMed:12766977, ECO:0000269,PubMed:14648196, ECO:0000269,PubMed:14711882, ECO:0000269,PubMed:14724127, ECO:0000269,PubMed:15495235, ECO:0000269,PubMed:15800015, ECO:0000269,PubMed:16009553, ECO:0000269,PubMed:16376610, ECO:0000269,PubMed:16865695, ...

TY - JOUR. T1 - Differential contribution of cardiac sarcomeric proteins in the myofibrillar force response to stretch. AU - Ait Mou, Younss. AU - Le Guennec, Jean Yves. AU - Mosca, Emilio. AU - De Tombe, Pieter P.. AU - Cazorla, Olivier. PY - 2008/10. Y1 - 2008/10. N2 - The present study examined the contribution of myofilament contractile proteins to regional function in guinea pig myocardium. We investigated the effect of stretch on myofilament contractile proteins, Ca2+ sensitivity, and cross-bridge cycling kinetics (K tr) of force in single skinned cardiomyocytes isolated from the sub-endocardial (ENDO) or sub-epicardial (EPI) layer. As observed in other species, ENDO cells were stiffer, and Ca2+ sensitivity of force at long sarcomere length was higher compared with EPI cells. Maximal K tr was unchanged by stretch, but was higher in EPI cells possibly due to a higher α-MHC content. Submaximal Ca2+-activated K tr increased only in ENDO cells with stretch. Stretch of skinned ENDO muscle ...

LEUCINE IS THE TRIGGER!!!. New scientific studies show that Leucine is a powerful nutritional activator of muscle protein synthesis*. It activates the anabolic pathway for building muscle.. These new findings confirm that within the context of a mixed macronutrient intake, suboptimal protein doses can be made more effective in stimulating myofibrillar protein synthesis, through the addition of a high proportion of free Leucine.. This branched chained amino acid is essential for achieving a positive nitrogen balance in building lean muscle mass. Leucine is discribed as the trigger of muscle protein synthesis.. * Muscle protein synthesis (MPS) is the rebuilding of muscle tissue and it occurs as a result of the stresses that we place on our body, whether it is to repair injury (such as a muscle tear) or because we intentionally try to damage it (microtrauma from training).. ...

Based on the framework of sliding-filament theory and on the cross-bridges dynamics, a mathematical model for the simulation of the force response and length change of individual myofibril is presented. The myofibril is modeled as a group of segments placed in series, each segment represents a half-sarcomere with active and elastic properties. A multiple-state cross-bridge formalism relates the half Sarcomere force to the chemical kinetics of ATP hydrolysis. The corresponding system of nonlinear nonlocal partial differential equations of the model is analyzed. A numerical approach is introduced and some numerical tests are performed. The proposed in-silico model enables the study of biologically relevant process in the muscle contraction process, also in the case of muscular diseases, with reasonable computational effort. ...

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This is a list of changes made recently to pages linked from a specified page (or to members of a specified category). Pages on your watchlist are bold. ...

In electron micrographs of the sarcomere, the M line appears as a series of parallel electron-dense lines in the central zone of the A band impliing that the M line is needed for the regular packing of the thick filaments. The M line maintains the myosin filaments in a hexagonal lattice ...

Tropomodulin is a 40.6-kD protein that colocalizes with actin filament pointed ends in skeletal muscle. We report the sequence of two partial-length complementary DNA (cDNA) clones of rat cardiac tropomodulin that cover 90% of the coding region. The cDNA sequence is 90% conserved between human and r …

MCL_coexpression_mm9,gostat_on_MCL_coexpression=GO:0030016;myofibril;4.00661982209194e-17;17929,21393,68828,59091,22003,17930,64009,26549,11464,13405,22138,20928,11472,13346,21916,56376!GO:0043292;contractile fiber;4.00661982209194e-17;17929,21393,68828,59091,22003,17930,64009,26549,11464,13405,22138,20928,11472,13346,21916,56376!GO:0030017;sarcomere;9.10776078501327e-17;17929,21393,68828,59091,22003,17930,64009,26549,11464,13405,22138,20928,11472,13346,56376!GO:0044449;contractile fiber part;1.41829398911132e-16;17929,21393,68828,59091,22003,17930,64009,26549,11464,13405,22138,20928,11472,13346,56376!GO:0031674;I band;3.26452523337004e-12;21393,68828,59091,26549,11464,13405,22138,11472,13346,56376!GO:0005856;cytoskeleton;1.67134528778977e-11;17929,16332,58522,18541,16562,19400,11733,13405,23999,93677,17913,20391,11472,21916,24053,360013,68828,22003,17930,11464,22138,68760,13346,12632!GO:0030018;Z ...

The effects of high pressure (to 600 MPa) at different temperatures (20 to 60 °C) for 20 min on protein solubilization and electrophoretic pattern in beef post-rigor longissimus dorsi muscle were studied. The results showed that protein solubilization increased with increasing temperature, especially from 40 °C to 60 °C. A regular trend of protein solubilization was found when isolated myofibrils were subjected to high pressure at different temperatures, an increase was observed with increasing pressure up to about 400 MPa, solubility then decreasing to 600 MPa. Electrophoretic profiles showed that myosin light chains and actin thin filaments were sensitive to pressure, and were released from myofibrils subjected to 100 MPa and higher pressures at the different temperatures.

The signaling mechanisms involved in actin filament formation for myofibril formation, which is required for growth factor-induced muscle maturation and hypertrophy, remain unclear. Takano et al. (see the Perspective by Gautel and Ehler) now show that the mechanism involves the interaction of nebulin and N-WASP. N-WASP is an activator of the Arp2/3 complex, which induces branched actin filaments in nonmuscle cells. The nebulin-N-WASP complex formed in muscle, however, causes nucleation of unbranched actin filaments within myofibrils without the Arp2/3 complex. Nebulin-N-WASP-mediated myofibrillar actin filament formation is required for muscle hypertrophy and might explain a congenital hereditary neuromuscular disorder caused by nebulin gene mutation: nemaline myopathy.. K. Takano, H. Watanabe-Takano, S. Suetsugu, S. Kurita, K. Tsujita, S. Kimura, T. Karatsu, T. Takenawa, T. Endo, Nebulin and N-WASP cooperate to cause IGF-1-induced sarcomeric actin filament formation. Science 330, 1536-1540 ...

This study was designed to examine energetic behaviour of skeletal muscle subsarcolemmal and intermyofibrillar mitochondrial populations. The data show tha

Paranemin was initially found to copurify with the intermediate filament (IF) proteins vimentin and desmin from embryonic chick skeletal muscle and was described as an IF-associated protein (IFAP). We have purified paranemin from embryonic chick skeletal muscle, prepared antibodies, and demonstrated that they label at the Z-lines of both adult avian and porcine cardiac and skeletal muscle myofibrils. We determined the cDNA sequence of paranemin by immunoscreening a λgt22A cDNA library from embryonic chick skeletal muscle. Northern blot analysis revealed a single transcript of 5.3 kilobases, which is much smaller than predicted from the size of paranemin (280 kDa) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The derived amino acid sequence of paranemin (1,606 residues; 178,161 kDa) contains the conserved IF rod domain (308 amino acids), which has highest homology to the rod domains of nestin and tanabin. Thus, paranemin is an IF protein rather than an IFAP. Sequence analysis ...

TY - JOUR. T1 - Comparison of M-line and other myofibril components during reversible phorbol ester treatment.. AU - Doetschman, T. C.. AU - Eppenberger, H. M.. PY - 1984/3/1. Y1 - 1984/3/1. N2 - The events occurring during phorbol ester mediated destruction of myofibrils in differentiated muscle cells were followed at the fluorescence and electron microscope levels using antibodies which bind troponin-T, a newly discovered 185 000 dalton M-line protein called myomesin and muscle type creatine kinase. The following series of events is proposed. Within one day of phorbol ester treatment, Z-bands and thin filaments, including troponin-T, are absent from many myofibrils resulting in the rapid loss of longitudinal and lateral alignment. A-bands become randomly oriented and clustered into ever smaller compartments within the rounding, myosac-like, multinucleated cells until after 3 days of treatment they too disappear. The M-line proteins are always present in existing A-bands. These results suggest ...

Barbat-Artigas, S., Rolland, Y., Zamboni, M., and M. Aubertin-Leheudre (2012). How to assess functional status: a new muscle quality index. The Journal of Nutrition, Health & Aging, 16(1), 67-77.. Churchward-Venne, T. a, Burd, N. a, Mitchell, C. J., West, D. W. D., Philp, A., Marcotte, G. R. and S.M. Phillips (2012). Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men. The Journal of Physiology, 590 (Pt 11): 2751-65.. Dellal A., Chamari, K. and A. Owen (2013). How and When to Use an Injury Prevention Intervention in Soccer, Muscle Injuries in Sport Medicine, Prof. Gian Nicola Bisciotti (Ed.), ISBN: 978-953-51-1198-6.. Dupont, G., Nedelec, M., McCall, A., McCormack, D., Berthoin, S., & U. Wisløff (2010). Effect of 2 soccer matches in a week on physical performance and injury rate. The American Journal of Sports Medicine, 38(9), 1752-1758. Ekstrand, J., Hägglund M. and M. ...

In order to figure out the effect of CaCl2 on the tenderizing pathway of goose meat, breast muscles of thirty-two Eastern Zhejiang White Geese were divided into three treatments: the control, 150 and 300mM CaCl2. Shear force, myofibrillar fraction index (MFI), actin filaments and F-actin, G-actin and tropomodulins (Tmods) levels were investigated during 168h. Results showed that 300mM treatment had lower shear force at 48, 96 and 168h and higher MFI at 24, 48, 96 and 168h than the control. The rate of actin filaments disruption, the decrease of F-actin, the degradation of Tmods, the increase of G-actin in 300mM treatment was faster than 150mM treatment; the rate in the control was the slowest among treatments ...

The efficient functioning of striated muscle is dependent upon the precise interactions and alignment of complex cytoskeletal networks. For example, sarcomeres, the basic contractile units of myofibrils, are comprised of uniformly arranged filament systems and regulatory proteins. The actin-containing thin filaments are anchored in the Z-lines and extend toward the middle of the sarcomere, the M-line, where they interact with the myosin-containing thick filaments to drive contraction. A third filament system is composed of single molecules of titin, the largest known vertebrate protein (∼3.7 MDa). Titin filaments span half sarcomeres, with their N-termini overlapping in the Z-lines and their C-termini overlapping in the M-lines, thus forming a continuous filament system among adjacent myofibrils (Obermann et al., 1996; Gregorio et al., 1998; Mues et al., 1998). Based on the assembly properties, molecular layout and modular structure of titin, it is proposed to act as a template for ...

Many of cTnT mutations linked to cardiomyopathies fall the TNT1 domain/N terminal tail region of unresolved high definition structure. This region (∼94-170) of cTnT is critical to Tm binding and contraction regulation. Here, the impact of the E163R mutation in cTnT-TNT1 on contractile function and tension cost was investigated using intact and skinned preparations from WT and transgenic mouse hearts. Methods: Left and right ventricular trabeculae were dissected from non-transgenic wild type (WT) and heterozygous (E163R or R92Q) mouse hearts and mounted isometrically to record twitch tension or, when skinned, Ca2+ activated force. Myofibrillar ATPase activity was measured by fluorimetric enzyme coupled assay (de Tombe and Stienen, 1995). In this thesis we aimed to assess the primary alterations of the contractile function and of tension cost caused by E163R cTnT-TNT1domain mutation, using skinned preparations or single myofibrils from WT and transgenic mouse hearts. Than we aimed to ...

TY - JOUR. T1 - Rheological parameters as predictors of protein functionality. T2 - A model study using myofibrils of different fibre-type composition. AU - Egelandsdal, Bjorg. AU - Martinsen, Berit. AU - Autio, Karin. PY - 1995. Y1 - 1995. U2 - 10.1016/0309-1740(95)80011-5. DO - 10.1016/0309-1740(95)80011-5. M3 - Article. VL - 39. SP - 97. EP - 111. JO - Meat Science. JF - Meat Science. SN - 0309-1740. IS - 1. ER - ...

Variations of free calcium concentration ([Ca2+]) are powerful intracellular signals, controlling contraction as well as metabolism in muscle cells. To fully understand the role of calcium redistribution upon excitation and contraction in skeletal muscle cells, the local [Ca2+] in different compartments needs to be taken into consideration. Fluorescent probes allow the determination of [Ca2+] in the cytosol where myofibrils are embedded, the lumen of the sarcoplasmic reticulum (SR) and the mitochondrial matrix. Previously, models have been developed describing intracellular calcium handling in skeletal and cardiac muscle cells. However, a comprehensive model describing the kinetics of the changes in free calcium concentration in these three compartments is lacking. We designed a new 3D compartmental model of the half sarcomere with radial symmetry, which accounts for diffusion of Ca2+ into the three compartments and simulates its dynamics at rest and at various rates of stimulation in mice ...

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Volume overload refers to the state of one of the chambers of the heart in which too large a volume of blood exists within it for it to function efficiently. Ventricular volume overload is approximately equivalent to an excessively high preload. It is a cause of cardiac failure. In accordance with the Frank-Starling law of the heart, the myocardium contracts more powerfully as the end-diastolic volume increases. Stretching of the myofibrils in cardiac muscle causes them to contract more powerfully due to a greater number of cross-bridges being formed between the myofibrils within cardiac myocytes. This is true up to a point, however beyond this there is a loss of contractile ability due to loss of connection between myofibrils; see figure. Various pathologies, listed below, can lead to volume overload. Different mechanisms are involved depending on the cause, however the common theme is that of a high cardiac output with a low or normal afterload. The output may be high due to the inefficiency ...

In this study, the chemical characterization of glycoconjugates of myofibrillar proteins from grass carp conjugated with glucose via Maillard reaction for up to 24 h of dry-heating was investigated, and their impacts on the microbial community in vitro human fecal fermentation were firstly evaluated by high-

The muscular system is the biological system of an organism that allows it to move. The muscular system in vertebrates is controlled through the nervous system, although some muscles (such as the cardiac muscle) can be completely autonomous.. Muscles. There are distincts types of muscles: skeletal muscles, heart muscles and smooth muscles.. Skeletal muscle. Skeletal muscle fibers are multinucleated, with the cells nuclei located just beneath the plasma membrane. The cell comprises a series of striped or striated, thread-like myofibrils. Within each myofibril there are protein filaments that are anchored by dark Z lines. The fibre is one long continuous thread-like structure. The smallest cross section of skeletal muscle is called a sarcomere which is the functional unit within the cell. It extends from one Z line to the next attached Z line. The individual sarcomere has alternating thick myosin and thin actin protein filaments. Myosin forms the center or middle of each sarcomere. The exact ...

Animal models have been used to examine the development of the classic phenotypic findings of LVH, myocyte disarray and interstitial fibrosis. In a transgenic rabbit model of HCM (β-MyHC-Q403), myocyte disarray occurred before cellular hypertrophy and fibrosis (10). The transgenic rabbit model is interesting because beta-myosin heavy chain is the predominant protein, as in humans; this is unlike in mice, in which alpha-myosin heavy chain is the predominant protein. With respect to imaging findings, a reduction in septal and lateral systolic and diastolic mitral annulus velocities was the earliest observation when transgenic mutant animals were compared with nontransgenic or wild-type animals (11). Interestingly, myocardial velocities were not related to disarray, hypertrophy, or collagen volume fraction. Conversely, reduced calcium sensitivity of myofibrillar ATPase activity was detected in these animals at the same time abnormal myocardial function was observed by imaging. With disease ...

The |i|Journal of Biomedical Optics|/i| (JBO) publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and biomedical research.

Muscle fibre cells are joined together in order to gain strength. They all share muscle sarcoplasm which is made up of mitochondria, endoplasmic reticulum, cytoplasm and nuclei.. Microscopic structure. There are two main proteins involved in myofibrils:. Myosin: These are thick, rod shaped proteins with protruding bulbous heads.. Actin: Two thin strands wrapped round each other.. The myofibril seems *****ed as it two types of bands. The A band is the darker ***** where the actin and myosin overlap, and the I band is where they dont overlap.. Marking the end of the sarcomere is the Z line, and between the two darker *****s there is an H zone.. Types of muscle Fibre. Slow twitch: Muscle fibre that need aerobic respiration to prevent the build…. ...

Honestly, based purely on my observations here, the MFM situation with the first doctor is a little unusual. Its actually pretty normal for MFMs to either be a primary doctor by themselves with no regular OB in the picture at all, or MFMs that co-manage with the OB doing the typical OB stuff while the MFM keeps an extra eye on things and directs the plan. Many MFMs dont deliver at all. My personal MFM situation is my MFM can do either, she is comfortable being a primary and delivering her patients, or co-managing (although she confided to me that she will not co-manage with just any old OB, it has to be someone she feels is a quality OB.) Ive not heard of an MFM that co-manages but takes the delivery except in emergencies...I dont really understand the OBs role with the first MFM. In any case, as long as you have an OB that you like and trust to deliver you, as far as my non-expert understanding, theres no reason they cant deliver you whether your pregnancy goes smoothly or not unless ...

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Title: Effect of contraction intensity and feeding on myofibrillar and collagen protein synthesis in human skeletal muscle. Divergent training-adaptation and molecular signaling following light- and heavy-load resistance exercise. University of Copenhagen. ...

Myosin filaments lie in a line parallel to each other, bases attached at the M - line. Actin filaments alignat the Z - line. Both overlap producing a striped appearance in the myofibril.. Upon contraction: A band (actin & myosin) stays the same length as always the length of myosin. H zone (myosin) shortens as more actin slides into A band. I band (actin) shortens as actin slides into A band.. Z lines (run through centre of I band) move closer together as ore actin slides under myosin.. Sarcomere is the distance between the Z lines.. ...

The human heart is a mechanical pump that contracts and relaxes in a cyclical fashion. Contraction of the heart muscles is necessary to ensure satisfactory perfusion of distal tissues, which require nutrients and oxygen for their metabolic needs. Likewise, the heart is required to adequately relax to allow for adequate filling that will guarantee the requisite cardiac output (CO). CO is a product of the stroke volume (SV) and the heart rate (HR). Therefore, adequate left ventricular filling in a properly relaxed heart increases the SV and consequently the forward flow. Cardiac contraction occur during the systolic phase of the cardiac cycle while the heart relaxes during the diastolic phase of the cardiac cycle. The hearts contractile apparatus consist of striated smooth muscles that are collectively known as cardiac myocytes. Each myocyte is furnished with a plasma membrane also known as sarcolemma, a rich network of mitochondria (because of high energy required in form of ATP), myofibrils ...

12.08.2015. mtbrDot. Several days ago in the post of muscle fibres we told you that muscles consist of myofibrils (contractive units) and mitochondria (energy units) and that strength depends on th...

Relaxed sarcomeres contain myosin heads that have released their pull on the thin filaments. This allows them to return back to their relaxed state and cau

Givli, Sefi and Bhattacharya, Kaushik (2009) A coarse-grained model of the myofibril: Overall dynamics and the evolution of sarcomere non-uniformities. Journal of the Mechanics and Physics of Solids, 57 (2). pp. 221-243. ISSN 0022-5096. https://resolver.caltech.edu/CaltechAUTHORS:20090424-093629858 ...

Weve conquered all the territories above 0m and under. In this article, we set out to show you and explain what happens in your body as you descend into the big blue world.

I am trying to carry out the fractionation of cardiac tissue.I am specifically looking to isolate mitochondria, myofibril and nuclei. Anyone got any ideas ...

For the past 5 odd months this has been the norm. Attached image is for the past 20 odd hours on my 1M line :sick: Guess thats what Telkom means with...