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Sample records for barnacle muscle fibers

  1. Memristive Model of the Barnacle Giant Muscle Fibers

    Science.gov (United States)

    Sah, Maheshwar Pd.; Kim, Hyongsuk; Eroglu, Abdullah; Chua, Leon

    The generation of action potentials (oscillations) in biological systems is a complex, yet poorly understood nonlinear dynamical phenomenon involving ions. This paper reveals that the time-varying calcium ion and the time-varying potassium ion, which are essential for generating action potentials in Barnacle giant muscle fibers are in fact generic memristors in the perspective of electrical circuit theory. We will show that these two ions exhibit all the fingerprints of memristors from the equations of the Morris-Lecar model of the Barnacle giant muscle fibers. This paper also gives a textbook reference to understand the difference between memristor and nonlinear resistor via analysis of the potassium ion-channel memristor and calcium ion-channel nonlinear resistor. We will also present a comprehensive in-depth analysis of the generation of action potentials (oscillations) in memristive Morris-Lecar model using small-signal circuit model and the Hopf bifurcation theorem.

  2. 31P nuclear magnetic resonance measurements of intracellular pH in giant barnacle muscle

    International Nuclear Information System (INIS)

    The accuracy of intracellular pH (pH/sub i/) measurements by 31P nuclear magnetic resonance (NMR) spectroscopy was examined in single muscle fibers from the giant barnacle, Balanus nubilis. The pH/sub i/ was derived from the chemical shifts of 2-deoxy-D-glucose-6-phosphate and inorganic phosphate. In fibers superfused with sea water at pH 7.7, pH/sub i/ = 7.30 +/- 0.02 at 200C. Experimentally induced pH/sub i/ changes were followed with a time resolution of 3 min. Intracellular alkalinization was induced by exposure to NH3Cl and intracellular acidification followed when NH3 was removed. Then acid extrusion was stimulated by exposure to bicarbonate containing sea water. In single muscle fibers 31P NMR results were in excellent agreement with microelectrode studies over the pH range of 6.5 to 8.0. The initial acid extrusion rate was 1.7 +/- 0.3 mmol x 1-1 x min-1 at pH/sub i/ 6.75. The authors results showed that 31P NMR is a reliable in vivo pH probe

  3. The morphological development of the locomotor and cardiac muscles of the migratory barnacle goose (Branta leucopsis)

    NARCIS (Netherlands)

    Bishop, CM; Butler, PJ; ElHaj, AJ; Egginton, S; Loonen, MJJE

    1996-01-01

    The masses of the locomotor and cardiac muscles of wild barnacle goose goslings, from a migratory population, were examined systematically during development and their values compared to those of pre-migratory geese. Pre-flight development was typified by approximately linear increases of body, leg,

  4. [Muscle fiber atrophy].

    Science.gov (United States)

    Nonaka, Ikuya

    2012-01-01

    Muscle fibers have been classified into two major forms of red (slow twitch) and white (fast twitch) muscles. The red muscle utilizes lipid as energy source through mitochondrial metabolism and function to sustain the position against gravity (sometimes called as antigravity muscle). Under microgravity the red muscle is selectively involved. In our unloading study by hindlimb suspension experiment on rats, the one of the representative red muscle of soleus muscle underwent rapid atrophy; they reduced their weights about 50% after 2 week-unloading. In addition, myofibrils were occasionally markedly disorganized with selective thin filament loss. Mitochondria in the degenerated area were decreased in number. The white muscle fibers in the soleus muscle had mostly transformed to the red ones. It took about 1 month to recover morphologically. The satellite cell playing a major role in muscle regeneration was not activated. There still remained unsolved what are the mechanosensors to keep muscle function under normal gravity. Dr Nikawa's group proposed that one of ubiquitin ligases, Cbl-b is activated under microgravity and induces muscle fiber degeneration. There might be many factors to induce muscle atrophy and degeneration under microgravity. Further study is necessary to explore the pathomechanism of muscle atrophy in disused and under immobility conditions. PMID:23196603

  5. Simultaneous bidirectional magnesium ion flux measurements in single barnacle muscle cells by mass spectrometry

    International Nuclear Information System (INIS)

    Stable isotopes of Mg were used to measure bidirectional magnesium ion fluxes in single barnacle giant muscle fibers immersed in Ca- and Na-free, isosmotic media. Measurements were made using a mass spectrometric technique, thermal ionization mass spectrometry (TIMS), in conjunction with atomic absorption spectroscopy. Kinetic relations based on a first-order model were developed that permit the determination of unidirectional rate coefficients for Mg influx, ki, and efflux, ke, in the same experiment from knowledge of initial conditions and the initial and final ratios of 26Mg/24Mg and 25Mg/24Mg in ambient solutions (i.e., by isotope dilution). Such determinations were made for three values of the external Mg ion concentration: 5, 25, and 60 mM. At the concentration [Mg+2]o = 5 mM, ki and ke were about equal at a value of 0.01 min-1. At the higher values of [Mg+2]o, the values of ke increased along a curve suggesting saturation, whereas the values of ki remained essentially constant. As could be expected on the basis of a constant ki, the initial influx rate varied in direct linear proportion to [Mg+2]o, and was 11.8 pmol/cm2s when [Mg+2]o was 5 mM. However, the initial efflux rate appeared to increase nonlinearly with [Mg+2]o, varying from 13.4 pmol/cm2s ([ Mg+2]o = 5 mM) to approximately 80 pmol/cm2s ([Mg+2]o = 60 mM). The results are consistent with a model that assumes Mg influx to be mainly an electrodiffusive inward leak with PMg = 0.07 cm/s and Mg efflux to be almost entirely by active transport processes. Where comparisons can be made, the rate coefficients determined from stable isotope measurements agree with those previously obtained using radioactive Mg. The rate coefficients can be used to correctly predict time-dependent changes in total fiber Mg content

  6. Muscle Fiber Types and Training.

    Science.gov (United States)

    Karp, Jason R.

    2001-01-01

    The specific types of fibers that make up individual muscles greatly influence how people will adapt to their training programs. This paper explains the complexities of skeletal muscles, focusing on types of muscle fibers (slow-twitch and fast-twitch), recruitment of muscle fibers to perform a motor task, and determining fiber type. Implications…

  7. Human Muscle Fiber

    Science.gov (United States)

    2003-01-01

    The stimulus of gravity affects RNA production, which helps maintain the strength of human muscles on Earth (top), as seen in this section of muscle fiber taken from an astronaut before spaceflight. Astronauts in orbit and patients on Earth fighting muscle-wasting diseases need countermeasures to prevent muscle atrophy, indicated here with white lipid droplets (bottom) in the muscle sample taken from the same astronaut after spaceflight. Kerneth Baldwin of the University of California, Irvine, is conducting research on how reducing the stimulus of gravity affects production of the RNA that the body uses as a blueprint for making muscle proteins. Muscle proteins are what give muscles their strength, so when the RNA blueprints aren't available for producing new proteins to replace old ones -- a situation that occurs in microgravity -- the muscles atrophy. When the skeletal muscle system is exposed to microgravity during spaceflight, the muscles undergo a reduced mass that translates to a reduction in strength. When this happens, muscle endurance decreases and the muscles are more prone to injury, so individuals could have problems in performing extravehicular activity [space walks] or emergency egress because their bodies are functionally compromised.

  8. Hydrostatic compression in glycerinated rabbit muscle fibers.

    OpenAIRE

    Ranatunga, K.W.; Fortune, N S; Geeves, M A

    1990-01-01

    Glycerinated muscle fibers isolated from rabbit psoas muscle, and a number of other nonmuscle elastic fibers including glass, rubber, and collagen, were exposed to hydrostatic pressures of up to 10 MPa (100 Atm) to determine the pressure sensitivity of their isometric tension. The isometric tension of muscle fibers in the relaxed state (passive tension) was insensitive to increased pressure, whereas the muscle fiber tension in rigor state increased linearly with pressure. The tension of all o...

  9. 'Flying barnacles'

    DEFF Research Database (Denmark)

    Tøttrup, Anders P; Chan, Benny K K; Koskinen, Hannu;

    2010-01-01

    The presence of adult barnacles of Fistulobalanus pallidus (Darwin) and Fistulobalanus albicostatus (Pilsbry) attached to field-readable plastic leg rings on the Lesser Black-backed Gull Larus fuscus in Northern Europe is reported. L. fuscus is a long-distance palaearctic migrant, breeding in...

  10. Emerin increase in regenerating muscle fibers

    Directory of Open Access Journals (Sweden)

    S Squarzoni

    2009-06-01

    Full Text Available The fate of emerin during skeletal muscle regeneration was investigated in an animal model by means of crush injury. Immunofluorescence, immunoblotting and mRNA analysis demonstrated that emerin level is increased in regenerating rat muscle fibers with respect to normal mature myofibers. This finding suggests an involvement of emerin during the muscle fiber regeneration process, in analogy with its reported involvement in muscle cell differentiation in vitro. The impairment of skeletal muscle physiological regeneration or reorganization could be a possible pathogenetic mechanism for Emery Dreifuss muscular dystrophy.

  11. Cell death regulates muscle fiber number.

    Science.gov (United States)

    Sarkissian, Tatevik; Arya, Richa; Gyonjyan, Seda; Taylor, Barbara; White, Kristin

    2016-07-01

    Cell death can have both cell autonomous and non-autonomous roles in normal development. Previous studies have shown that the central cell death regulators grim and reaper are required for the developmentally important elimination of stem cells and neurons in the developing central nervous system (CNS). Here we show that cell death in the nervous system is also required for normal muscle development. In the absence of grim and reaper, there is an increase in the number of fibers in the ventral abdominal muscles in the Drosophila adult. This phenotype can be partially recapitulated by inhibition of cell death specifically in the CNS, indicating a non-autonomous role for neuronal death in limiting muscle fiber number. We also show that FGFs produced in the cell death defective nervous system are required for the increase in muscle fiber number. Cell death in the muscle lineage during pupal stages also plays a role in specifying fiber number. Our work suggests that FGFs from the CNS act as a survival signal for muscle founder cells. Thus, proper muscle fiber specification requires cell death in both the nervous system and in the developing muscle itself. PMID:27131625

  12. Regional heterogeneity in muscle fiber strain: the role of fiber architecture

    OpenAIRE

    Azizi, E.; Deslauriers, Amber R.

    2014-01-01

    The force, mechanical work and power produced by muscle fibers are profoundly affected by the length changes they undergo during a contraction. These length changes are in turn affected by the spatial orientation of muscle fibers within a muscle (fiber architecture). Therefore any heterogeneity in fiber architecture within a single muscle has the potential to cause spatial variation in fiber strain. Here we examine how the architectural variation within a pennate muscle and within a fusiform ...

  13. Regional heterogeneity in muscle fiber strain: The role of fiber architecture

    OpenAIRE

    Azizi, E.

    2014-01-01

    The force, mechanical work and power produced by muscle fibers are profoundly affected by the length changes they undergo during a contraction. These length changes are in turn affected by the spatial orientation of muscle fibers within a muscle (fiber architecture). Therefore any heterogeneity in fiber architecture within a single muscle has the potential to cause spatial variation in fiber strain. Here we examine how the architectural variation within a pennate muscle and within a fusiform...

  14. ANATOMY AND FIBER TYPE COMPOSITION OF HUMAN INTERARYTENOID MUSCLE

    OpenAIRE

    Tellis, Cari M.; Rosen, Clark; Thekdi, Apurva; Sciote, James J.

    2004-01-01

    Intrinsic laryngeal muscle investigations, especially those of the interarytenoid (IA) muscle, have been primarily teleologically based. We determined IA muscle anatomy and histochemical and immunohistochemical classification of extrafusal and intrafusal (muscle spindle) fibers in 5 patients. Extrafusal fibers were oxidative type I and glycolytic types IIA and IIX. Intrafusal fibers of muscle spindles were identified by the presence of tonic and neonatal myosin. The results demonstrate that t...

  15. Tetranectin in slow intra- and extrafusal chicken muscle fibers

    DEFF Research Database (Denmark)

    Xu, X; Gilpin, B; Iba, K;

    2001-01-01

    heavy chains (MHC) and double immunostaining techniques, we found that tetranectin was restricted to slow (type I) muscle fibers. Similarly only slow intrafusal fibers accumulated tetranectin. The pattern of immunostaining in chickens differs markedly from that seen in mouse muscles, indicating that...... tetranectin performs a role in muscle that is not associated with a hitherto recognized muscle type or function....

  16. Skeletal muscle fiber type: using insights from muscle developmental biology to dissect targets for susceptibility and resistance to muscle disease.

    Science.gov (United States)

    Talbot, Jared; Maves, Lisa

    2016-07-01

    Skeletal muscle fibers are classified into fiber types, in particular, slow twitch versus fast twitch. Muscle fiber types are generally defined by the particular myosin heavy chain isoforms that they express, but many other components contribute to a fiber's physiological characteristics. Skeletal muscle fiber type can have a profound impact on muscle diseases, including certain muscular dystrophies and sarcopenia, the aging-induced loss of muscle mass and strength. These findings suggest that some muscle diseases may be treated by shifting fiber type characteristics either from slow to fast, or fast to slow phenotypes, depending on the disease. Recent studies have begun to address which components of muscle fiber types mediate their susceptibility or resistance to muscle disease. However, for many diseases it remains largely unclear why certain fiber types are affected. A substantial body of work has revealed molecular pathways that regulate muscle fiber type plasticity and early developmental muscle fiber identity. For instance, recent studies have revealed many factors that regulate muscle fiber type through modulating the activity of the muscle regulatory transcription factor MYOD1. Future studies of muscle fiber type development in animal models will continue to enhance our understanding of factors and pathways that may provide therapeutic targets to treat muscle diseases. WIREs Dev Biol 2016, 5:518-534. doi: 10.1002/wdev.230 For further resources related to this article, please visit the WIREs website. PMID:27199166

  17. An evaluation of the reliability of muscle fiber cross-sectional area and fiber number measurements in rat skeletal muscle

    OpenAIRE

    Ceglia, Lisa; Niramitmahapanya, Sathit; Price, Lori L; Harris, Susan S.; FIELDING, ROGER A.; Dawson-Hughes, Bess

    2013-01-01

    Background The reliability of estimating muscle fiber cross-sectional area (measure of muscle fiber size) and fiber number from only a subset of fibers in rat hindlimb muscle cross-sections has not been systematically evaluated. This study examined the variability in mean estimates of fiber cross-sectional area as a function of the number of fibers measured, and tested whether counting a subset of fibers in a cross-section could predict total fiber number in middle-aged rats. Results Soleus a...

  18. Repeatability of DTI-based skeletal muscle fiber tracking

    OpenAIRE

    Heemskerk, Anneriet M.; Sinha, Tuhin K.; Wilson, Kevin J.; Ding, Zhaohua; Damon, Bruce M.

    2010-01-01

    Diffusion tensor imaging (DTI)-based muscle fiber tracking enables the measurement of muscle architectural parameters, such as pennation angle (θ) and fiber tract length (Lft), throughout the entire muscle. Little is known, however, about the repeatability of either the muscle architectural measures or the underlying diffusion measures. Therefore, the goal of this study was to investigate the repeatability of DTI fiber tracking-based measurements and θ and Lft. Four DTI acquisitions were perf...

  19. Thixotropy and Rheopexy of Muscle Fibers Probed Using Sinusoidal Oscillations

    OpenAIRE

    Altman, David; Minozzo, Fabio C.; Rassier, Dilson E

    2015-01-01

    Length changes of muscle fibers have previously been shown to result in a temporary reduction in fiber stiffness that is referred to as thixotropy. Understanding the mechanism of this thixotropy is important to our understanding of muscle function since there are many instances in which muscle is subjected to repeated patterns of lengthening and shortening. By applying sinusoidal length changes to one end of single permeabilized muscle fibers and measuring the force response at the opposite e...

  20. Anisotropic Smoothing Improves DT-MRI-Based Muscle Fiber Tractography

    OpenAIRE

    Buck, Amanda K. W.; Ding, Zhaohua; Elder, Christopher P; Towse, Theodore F.; Damon, Bruce M.

    2015-01-01

    Purpose To assess the effect of anisotropic smoothing on fiber tracking measures, including pennation angle, fiber tract length, and fiber tract number in the medial gastrocnemius (MG) muscle in healthy subjects using diffusion-weighted magnetic resonance imaging (DW-MRI). Materials and Methods 3T DW-MRI data were used for muscle fiber tractography in the MG of healthy subjects. Anisotropic smoothing was applied at three levels (5%, 10%, 15%), and pennation angle, tract length, fiber tract nu...

  1. Glucose transporter expression in human skeletal muscle fibers

    DEFF Research Database (Denmark)

    Gaster, M; Handberg, A; Beck-Nielsen, H;

    2000-01-01

    amplification (TSA) technique to detect the localization of glucose transporter expression in human skeletal muscle. We found expression of GLUT-1, GLUT-3, and GLUT-4 in developing human muscle fibers showing a distinct expression pattern. 1) GLUT-1 is expressed in human skeletal muscle cells during gestation...... muscle fibers, only GLUT-4 was expressed at significant levels. GLUT-1 immunoreactivity was below the detection limit in muscle fibers, indicating that this glucose transporter is of minor importance for muscle glucose supply. Thus we hypothesize that GLUT-4 also mediates basal glucose transport in...

  2. Muscle fiber type diversification during exercise and regeneration.

    Science.gov (United States)

    Qaisar, Rizwan; Bhaskaran, Shylesh; Van Remmen, Holly

    2016-09-01

    The plasticity of skeletal muscle can be traced down to extensive metabolic, structural and molecular remodeling at the single fiber level. Skeletal muscle is comprised of different fiber types that are the basis of muscle plasticity in response to various functional demands. Resistance and endurance exercises are two external stimuli that differ in their duration and intensity of contraction and elicit markedly different responses in muscles adaptation. Further, eccentric contractions that are associated with exercise-induced injuries, elicit varied muscle adaptation and regenerative responses. Most adaptive changes are fiber type-specific and are highly influenced by diverse structural, metabolic and functional characteristics of individual fiber types. Regulation of signaling pathways by reactive oxygen species (ROS) and oxidative stress also plays an important role in muscle fiber adaptation during exercise. This review focuses on cellular and molecular responses that regulate the adaptation of skeletal muscle to exercise and exercise-related injuries. PMID:27032709

  3. Different modes of hypertrophy in skeletal muscle fibers

    OpenAIRE

    Paul, Angelika C.; Rosenthal, Nadia

    2002-01-01

    Skeletal muscles display a remarkable diversity in their arrangement of fibers into fascicles and in their patterns of innervation, depending on functional requirements and species differences. Most human muscle fascicles, despite their great length, consist of fibers that extend continuously from one tendon to the other with a single nerve endplate band. Other mammalian muscles have multiple endplate bands and fibers that do not insert into both tendons but terminate intrafascicularly. We in...

  4. Adherent Primary Cultures of Mouse Intercostal Muscle Fibers for Isolated Fiber Studies

    OpenAIRE

    Patrick Robison; Hernández-Ochoa, Erick O.; Schneider, Martin F.

    2011-01-01

    Primary culture models of single adult skeletal muscle fibers dissociated from locomotor muscles adhered to glass coverslips are routine and allow monitoring of functional processes in living cultured fibers. To date, such isolated fiber cultures have not been established for respiratory muscles, despite the fact that dysfunction of core respiratory muscles leading to respiratory arrest is the most common cause of death in many muscular diseases. Here we present the first description of an ad...

  5. Muscle organizers in Drosophila: the role of persistent larval fibers in adult flight muscle development

    Science.gov (United States)

    Farrell, E. R.; Fernandes, J.; Keshishian, H.

    1996-01-01

    In many organisms muscle formation depends on specialized cells that prefigure the pattern of the musculature and serve as templates for myoblast organization and fusion. These include muscle pioneers in insects and muscle organizing cells in leech. In Drosophila, muscle founder cells have been proposed to play a similar role in organizing larval muscle development during embryogenesis. During metamorphosis in Drosophila, following histolysis of most of the larval musculature, there is a second round of myogenesis that gives rise to the adult muscles. It is not known whether muscle founder cells organize the development of these muscles. However, in the thorax specific larval muscle fibers do not histolyze at the onset of metamorphosis, but instead serve as templates for the formation of a subset of adult muscles, the dorsal longitudinal flight muscles (DLMs). Because these persistent larval muscle fibers appear to be functioning in many respects like muscle founder cells, we investigated whether they were necessary for DLM development by using a microbeam laser to ablate them singly and in combination. We found that, in the absence of the larval muscle fibers, DLMs nonetheless develop. Our results show that the persistent larval muscle fibers are not required to initiate myoblast fusion, to determine DLM identity, to locate the DLMs in the thorax, or to specify the total DLM fiber volume. However, they are required to regulate the number of DLM fibers generated. Thus, while the persistent larval muscle fibers are not obligatory for DLM fiber formation and differentiation, they are necessary to ensure the development of the correct number of fibers.

  6. Effective fiber hypertrophy in satellite cell-depleted skeletal muscle

    OpenAIRE

    McCarthy, John J.; Mula, Jyothi; Miyazaki, Mitsunori; Erfani, Rod; Garrison, Kelcye; Farooqui, Amreen B.; Srikuea, Ratchakrit; Lawson, Benjamin A.; Grimes, Barry; Keller, Charles; Zant, Gary Van; Campbell, Kenneth S.; Esser, Karyn A.; Dupont-Versteegden, Esther E.; Peterson, Charlotte A.

    2011-01-01

    An important unresolved question in skeletal muscle plasticity is whether satellite cells are necessary for muscle fiber hypertrophy. To address this issue, a novel mouse strain (Pax7-DTA) was created which enabled the conditional ablation of >90% of satellite cells in mature skeletal muscle following tamoxifen administration. To test the hypothesis that satellite cells are necessary for skeletal muscle hypertrophy, the plantaris muscle of adult Pax7-DTA mice was subjected to mechanical overl...

  7. Mechanisms of nascent fiber formation during avian skeletal muscle hypertrophy

    Science.gov (United States)

    McCormick, K. M.; Schultz, E.

    1992-01-01

    This study examined two putative mechanisms of new fiber formation in postnatal skeletal muscle, namely longitudinal fragmentation of existing fibers and de novo formation. The relative contributions of these two mechanisms to fiber formation in hypertrophying anterior latissimus dorsi (ALD) muscle were assessed by quantitative analysis of their nuclear populations. Muscle hypertrophy was induced by wing-weighting for 1 week. All nuclei formed during the weighting period were labeled by continuous infusion of 5-bromo-2'-deoxyuridine (BrdU), a thymidine analog, and embryonic-like fibers were identified using an antibody to ventricular-like embryonic (V-EMB) myosin. The number of BrdU-labeled and unlabeled nuclei in V-EMB-positive fibers were counted. Wing-weighting resulted in significant muscle enlargement and the appearance of many V-EMB+ fibers. The majority of V-EMB+ fibers were completely independent of mature fibers and had a nuclear density characteristics of developing fibers. Furthermore, nearly 100% of the nuclei in independent V-EMB+ fibers were labeled. These findings strongly suggest that most V-EMB+ fibers were nascent fibers formed de novo during the weighting period by satellite cell activation and fusion. Nascent fibers were found primarily in the space between fascicles where they formed a complex anastomosing network of fibers running at angles to one another. Although wing-weighting induced an increase in the number of branched fibers, there was no evidence that V-EMB+ fibers were formed by longitudinal fragmentation. The location of newly formed fibers in wing-weighted and regenerating ALD muscle was compared to determine whether satellite cells in the ALD muscle were unusual in that, if stimulated to divide, they would form fibers in the inter- and intrafascicular space. In contrast to wing-weighted muscle, nascent fibers were always found closely associated with necrotic fibers. These results suggest that wing-weighting is not simply another

  8. Single muscle fiber proteomics reveals unexpected mitochondrial specialization

    DEFF Research Database (Denmark)

    Murgia, Marta; Nagaraj, Nagarjuna; Deshmukh, Atul S;

    2015-01-01

    Mammalian skeletal muscles are composed of multinucleated cells termed slow or fast fibers according to their contractile and metabolic properties. Here, we developed a high-sensitivity workflow to characterize the proteome of single fibers. Analysis of segments of the same fiber by traditional a...

  9. A method for determination of muscle fiber diameter using single fiber potential (SFP) analysis

    OpenAIRE

    Zalewska, Ewa; Nandedkar, Sanjeev D.; Hausmanowa-Petrusewicz, Irena

    2012-01-01

    We have used computer simulation to study the relationship between the muscle fiber diameter and parameters: peak-to-peak amplitude and duration of the negative peak of the muscle fiber action potential. We found that the negative peak duration is useful in the determination of fiber diameter via the diameter dependence of conduction velocity. We have shown a direct link between the underlying physiology and the measurements characterizing single fiber potential. Using data from simulations, ...

  10. Staining of Human Thyroarytenoid Muscle with Myosin Antibodies Reveals Some Unique Extrafusal Fibers, but no Muscle Spindles

    OpenAIRE

    Brandon, Carla A.; Rosen, Clark; Georgelis, George; Horton, Michael J.; Mooney, Mark P.; Sciote, James J.

    2003-01-01

    This study describes the myosin composition of extrafusal and intrafusal muscle fibers found in the human thyroarytenoid (TA) and sternohyoid (control) muscles. We sought to determine the presence of muscle spindles in the TA muscle, and to identify unusual extrafusal fiber types, using the commonly accepted approach of tissue stainng with myosin isoform specific antibodies. Extrafusal fibers are organized into motor units, which subsequently produce muscle movement, whereas intrafusal fibers...

  11. Differentiation of fast and slow muscle fibers by bioimpedance

    Science.gov (United States)

    Moreno, M.-V.; Khider, N.; Ribbe, E.; Damez, J.-L.

    2010-04-01

    The differentiation of fast and slow muscle fibers in vivo still requires constraining equipment (ergometer, biopsy ...) and invasive techniques. These fibers conduct the electrical current differently. Therefore the aim of this study is to see if it is possible to differentiate quickly, by bioimpedance, fast and slow fibers, and firstly muscles which are typical composed by slow or fast fibers. To do this, we used a multifrequency impedancemeter Z-Metrix® (BioparHom© Company, France). We collected the electrical characteristics (Longitudinal and Transversal, from 1 to 1000 kHz) for a population of 20 rats aged 70 days, on Soleus muscles (composed principally of slow fibers) and Extensor Digitroum Longus (EDL) muscles (composed principally of fast fibers). We compared the means of alpha (L/T), R (L/T) and X (L/T) with Wilcoxon tests. We obtained non significant differences between electrical data obtained on EDL and Soleus muscles, but we could see differences on graphics representation and with the example of one rat. Therefore, we can assume that differentiation, by bioimpedance, of muscles typed slow and fast fibers, could be possible.

  12. Effects of Purified Recombinant Neural and Muscle Agrin on Skeletal Muscle Fibers in Vivo

    OpenAIRE

    Bezakova, Gabriela; Helm, Johannes P.; Francolini, Maura; Lømo, Terje

    2001-01-01

    Aggregation of acetylcholine receptors (AChRs) in muscle fibers by nerve-derived agrin plays a key role in the formation of neuromuscular junctions. So far, the effects of agrin on muscle fibers have been studied in culture systems, transgenic animals, and in animals injected with agrin–cDNA constructs. We have applied purified recombinant chick neural and muscle agrin to rat soleus muscle in vivo and obtained the following results. Both neural and muscle agrin bind uniformly to the surface o...

  13. A method for preparing skeletal muscle fiber basal laminae

    International Nuclear Information System (INIS)

    Previous attempts to prepare skeletal muscle basal laminae (BL) for ultrastructural analyses have been hampered by difficulties in successfully removing skeletal muscle proteins and cellular debris from BL tubes. In the present study the authors describe a two phase method which results in an acellular muscle preparation, the BL of which are examined by light, transmission electron, and scanning electron microscopy. In the first phase, excised rat extensor digitorum longus muscles are subjected to x-radiation and then soaked in Marcaine to inhibit muscle regeneration and to destroy peripheral muscle fibers. The muscles are then grafted back into their original sites and allowed to remain in place 7-14 days to allow for maximal removal of degenerating muscle tissue with minimal scar tissue formation. In the second phase, the muscle grafts are subjected sequentially to EDTA, triton X-100, DNAase, and sodium deoxycholate to remove phagocytizing cells and associated degenerating muscle tissue. These procedures result in translucent, acellular muscle grafts which show numerous empty tubes of BL backed by endomysial collagenous fibers. These preparations should be useful for morphological analyses of isolated muscle BL and for possible in vitro studies by which the biological activity of muscle BL can be examined

  14. Regulation of Muscle Fiber Type and Running Endurance by PPARdelta

    Directory of Open Access Journals (Sweden)

    Wang Yong-Xu

    2004-01-01

    Full Text Available Endurance exercise training can promote an adaptive muscle fiber transformation and an increase of mitochondrial biogenesis by triggering scripted changes in gene expression. However, no transcription factor has yet been identified that can direct this process. We describe the engineering of a mouse capable of continuous running of up to twice the distance of a wild-type littermate. This was achieved by targeted expression of an activated form of peroxisome proliferator-activated receptor delta (PPARdelta in skeletal muscle, which induces a switch to form increased numbers of type I muscle fibers. Treatment of wild-type mice with PPARdelta agonist elicits a similar type I fiber gene expression profile in muscle. Moreover, these genetically generated fibers confer resistance to obesity with improved metabolic profiles, even in the absence of exercise. These results demonstrate that complex physiologic properties such as fatigue, endurance, and running capacity can be molecularly analyzed and manipulated.

  15. Regulation of muscle fiber type and running endurance by PPARdelta.

    Directory of Open Access Journals (Sweden)

    Yong-Xu Wang

    2004-10-01

    Full Text Available Endurance exercise training can promote an adaptive muscle fiber transformation and an increase of mitochondrial biogenesis by triggering scripted changes in gene expression. However, no transcription factor has yet been identified that can direct this process. We describe the engineering of a mouse capable of continuous running of up to twice the distance of a wild-type littermate. This was achieved by targeted expression of an activated form of peroxisome proliferator-activated receptor delta (PPARdelta in skeletal muscle, which induces a switch to form increased numbers of type I muscle fibers. Treatment of wild-type mice with PPARdelta agonist elicits a similar type I fiber gene expression profile in muscle. Moreover, these genetically generated fibers confer resistance to obesity with improved metabolic profiles, even in the absence of exercise. These results demonstrate that complex physiologic properties such as fatigue, endurance, and running capacity can be molecularly analyzed and manipulated.

  16. Ultrastructural alterations in skeletal muscle fibers of rats after exercise

    Science.gov (United States)

    Akuzawa, M.; Hataya, M.

    1982-01-01

    Ultrastructural alterations in skeletal muscle fibers were electron microscopically studied in rats forced to run on the treadmill until all-out. When they were mild and limited to relatively small areas, the reconstruction of filaments ensued within 10 days without infiltration of cells. When they were severe and extensive, phagocytes infiltrated in the lesions and removed degenerative sacroplasmic debris from muscle fibers. A little later, myoblasts appeared and regeneration was accomplished in 30 days in much the same manner as in myogenesis.

  17. Interictal conduction slowing in muscle fibers in hypokalemic periodic paralysis.

    Science.gov (United States)

    Troni, W; Doriguzzi, C; Mongini, T

    1983-11-01

    Conduction velocity in muscle fibers of the short head of biceps brachii was reduced between attacks in all the affected members of a family suffering from hypokalemic periodic paralysis. This finding represents a further evidence of a primary alteration of sarcolemmal function in this disease. Interictal conduction slowing in muscle fibers is consistent with the prevailing pathophysiologic hypothesis, which considers an increased membrane permeability to sodium ions as the fundamental defect underlying all forms of familial periodic paralysis. PMID:6685247

  18. Application of Computer System to Analysis of Muscle Morphology : Statistical Analysis of Spatial Pattern of Muscle Fibers

    OpenAIRE

    Hatano, Eiji; Miyamoto, Yoshihiro; Arita, Seizaburo; Hori, Yoshimi

    1984-01-01

    The spatial pattern of histochemically stained normal muscle fibers and reinnervated muscle fibers is called mosaic pattern or type grouping, respectively only from appearance. In this study we classified the spatial distribution of rats' anterior tibial muscle fibers into homogeneous, clustered and random distribution by the distance method of Hopkins and Skellam and quantitatively expressed the spatial distribution of each muscle fiber type using our newly developed computer system. The res...

  19. Mitochondrial specialization revealed by single muscle fiber proteomics

    DEFF Research Database (Denmark)

    Schiaffino, S; Reggiani, C; Kostrominova, T Y;

    2015-01-01

    to buffering the H2 O2 produced by the respiratory chain. Nicotinamide nucleotide transhydrogenase (NNT), the other major mito-chondrial enzyme involved in NADPH generation, is also more abundant in type 1 fibers. We suggest that the continuously active type 1 fibers are endowed with a more efficient......We have developed a highly sensitive mass spectrometry-based proteomic workflow to examine the proteome of single muscle fibers. This study revealed significant differences in the mitochondrial proteome of the four major fiber types present in mouse skeletal muscle. Here, we focus on Krebs cycle...... enzymes and in particular on the differential distribution of the two mitochondrial isocitrate dehydrogenases, IDH2 and IDH3. Type 1/slow fibers contain high levels of IDH2 and relatively low levels of IDH3, whereas fast 2X and 2B fibers show an opposite expression pattern. The findings suggest that in...

  20. Differential Responses of Soleus and Plantaris Muscle Fibers to Overloading

    Science.gov (United States)

    Kawano, Fuminori; Shibaguchi, Tsubasa; Ohira, Takashi; Nakai, Naoya; Ohira, Yoshinobu

    2013-02-01

    Responses of slow and fast fibers in soleus and plantaris muscles of adult rats to overloading by the tendon transection of synergists were studied. Overloading-related hypertrophy was noted in the slow fibers of plantaris and soleus, although the magnitude was greater in plantaris. Five genes with minor expression in slow soleus muscle were identified by microarray analysis. Base-line expressions of these genes in slow fibers of plantaris were also low. Further, repressive effects of overloading on these genes were seen in some fast fibers of plantaris, not in whole plantaris and soleus. The data suggested that the repression of particular genes might be related to the pronounced morphological response of fibers expressing type II, including I+II, myosin heavy chain (MyHC), although these genes with lower base-line expression in slow fibers did not respond to overloading.

  1. Assessment of Calcium Sparks in Intact Skeletal Muscle Fibers

    OpenAIRE

    Park, Ki Ho; Weisleder, Noah; Zhou, Jingsong; Gumpper, Kristyn; Zhou, Xinyu; Duann, Pu; Ma, Jianjie; Lin, Pei-Hui

    2014-01-01

    Maintaining homeostatic Ca2+ signaling is a fundamental physiological process in living cells. Ca2+ sparks are the elementary units of Ca2+ signaling in the striated muscle fibers that appear as highly localized Ca2+ release events mediated by ryanodine receptor (RyR) Ca2+ release channels on the sarcoplasmic reticulum (SR) membrane. Proper assessment of muscle Ca2+ sparks could provide information on the intracellular Ca2+ handling properties of healthy and diseased striated muscles. Althoug...

  2. Perlecan deficiency causes muscle hypertrophy, a decrease in myostatin expression, and changes in muscle fiber composition

    OpenAIRE

    Xu, Zhuo; Ichikawa, Naoki; Kosaki, Keisuke; Yamada, Yoshihiko; Sasaki, Takako; Sakai, Lynn Y.; Kurosawa, Hisashi; Hattori, Nobutaka; Arikawa-Hirasawa, Eri

    2010-01-01

    Perlecan is a component of the basement membrane that surrounds skeletal muscle. The aim of the present study is to identify the role of perlecan in skeletal muscle hypertrophy and myostatin signaling, with and without mechanical stress, using a mouse model (Hspg2−/−-Tg) deficient in skeletal muscle perlecan. We found that myosin heavy chain (MHC) type IIb fibers in the tibialis anterior (TA) muscle of Hspg2−/−-Tg mice had a significantly increased fiber cross-sectional area (CSA) compared to...

  3. Adaptations of human skeletal muscle fibers to spaceflight

    Science.gov (United States)

    Day, M. Kathleen; Allen, David L.; Mohajerani, Laleh; Greenisen, Michael C.; Roy, Roland R.; Edgerton, V. Reggie

    1995-01-01

    Human skeletal muscle fibers seem to share most of the same interrelationships among myosin ATPase activity, myosin heavy chain (MHC) phenotype, mitochondrial enzyme activities, glycolytic enzyme activities, and cross-sectional area (CSA) as found in rat, cat, and other species. One difference seems to be that fast fibers with high mitochrondrial content occur less frequently in humans than in the rat or cat. Recently, we have reported that the type of MHC expressed and the size of the muscle fibers in humans that have spent 11 days in space change significantly. Specifically, about 8% more fibers express fast MHCs and all phenotypes atrophy in the vastus lateralis (VL) post compared to preflight. In the present paper we examine the relationships among the population of myonuclei, MHC type, and CSA of single human muscle fibers before and after spaceflight. These are the first data that define the relationship among the types of MHC expressed, myonuclei number, and myonuclei domain of single fibers in human muscle. We then compare these data to similar measures in the cat. In addition, the maximal torque that can be generated by the knee extensors and their fatigability before and after spaceflight are examined. These data provide some indication of the potential physiologica consequences of the muscle adaptations that occur in humans in response to spaceflight.

  4. The Response of Tibialis Anterior Muscle Fibers in Mice to Increased Muscle Activity

    OpenAIRE

    HIROFUJI, Chiyoko; Ishihara, Akihiko; Nakatani, Toshiaki; ITOH, Kazuoa; ITOH, Minoru; Katsuta, Shigeru

    2001-01-01

    Cross-sectional areas and oxidative enzyme (succinate dehydrogenase) activities of fibers in the deep, middle, and superficial regions of the mouse tibialis anterior muscle were examined and compared after 30 days of increased muscle activity with voluntary running exercise. Eight 19-week-old male mice were assigned randomly to either a sedentary control (control, n=4) or voluntary running exercise (exercise, n=4) group. There were no differences in the cross-sectional area of fibers between ...

  5. Crossveinless and the TGFβ pathway regulate fiber number in the Drosophila adult jump muscle

    OpenAIRE

    Jaramillo, MaryAnn S.; Lovato, Candice V.; Baca, Erica M.; Cripps, Richard M.

    2009-01-01

    Skeletal muscles are readily characterized by their location within the body and by the number and composition of their constituent muscle fibers. Here, we characterize a mutation that causes a severe reduction in the number of fibers comprising the tergal depressor of the trochanter muscle (TDT, or jump muscle), which functions in the escape response of the Drosophila adult. The wild-type TDT comprises over 20 large muscle fibers and four small fibers. In crossveinless (cv) mutants, the numb...

  6. Effects of Treadmill Exercise on Muscle Fibers in Mice with Steroid Myopathy

    OpenAIRE

    Okita, Minoru; Yoshimura, Toshiro; Nakano, Jiro; Watabe, Miwako; Nagai, Tomoko; Kato, Katsutomo; Eguchi, Katsumi

    2001-01-01

    We studied the effect of treadmill exercise on muscle fibers in mice with experimental steroid myopathy. Frozen sections of the extensor digitorum longus (EDL) and soleus (SOL) muscles were stained with hematoxylin-eosin, and the muscle fiber diameters measured. In the EDL, muscle fiber diameters in the steroid groups decreased significantly compared with those in the control groups; moreover, muscle fiber diameters in the exercise groups increased significantly compared with those in the non...

  7. Molecular Mechanisms Regulating Muscle Fiber Composition Under Microgravity

    Science.gov (United States)

    Rosenthal, Nadia A.

    1999-01-01

    The overall goal of this project is to reveal the molecular mechanisms underlying the selective and debilitating atrophy of specific skeletal muscle fiber types that accompanies sustained conditions of microgravity. Since little is currently known about the regulation of fiber-specific gene expression programs in mammalian muscle, elucidation of the basic mechanisms of fiber diversification is a necessary prerequisite to the generation of therapeutic strategies for attenuation of muscle atrophy on earth or in space. Vertebrate skeletal muscle development involves the fusion of undifferentiated mononucleated myoblasts to form multinucleated myofibers, with a concomitant activation of muscle-specific genes encoding proteins that form the force-generating contractile apparatus. The regulatory circuitry controlling skeletal muscle gene expression has been well studied in a number of vertebrate animal systems. The goal of this project has been to achieve a similar level of understanding of the mechanisms underlying the further specification of muscles into different fiber types, and the role played by innervation and physical activity in the maintenance and adaptation of different fiber phenotypes into adulthood. Our recent research on the genetic basis of fiber specificity has focused on the emergence of mature fiber types and have implicated a group of transcriptional regulatory proteins, known as E proteins, in the control of fiber specificity. The restriction of E proteins to selected muscle fiber types is an attractive hypothetical mechanism for the generation of muscle fiber-specific patterns of gene expression. To date our results support a model wherein different E proteins are selectively expressed in muscle cells to determine fiber-restricted gene expression. These studies are a first step to define the molecular mechanisms responsible for the shifts in fiber type under conditions of microgravity, and to determine the potential importance of E proteins as

  8. Simulation of propagation in a bundle of skeletal muscle fibers: Modulation effects of passive fibers

    DEFF Research Database (Denmark)

    Henneberg, Kaj-åge; F.A., Roberge

    1997-01-01

    Computer simulations are used to study passive fiber modulation of propagation in a tightly packed bundle of frog skeletal muscle fibers (uniform fiber radius of 50 mu m). With T = 20 degrees C and a uniform nominal interstitial cleft width (d) over bar = 0.35 mu m, about 92% of the active fiber...... rate of rise of the action potential upstroke (V-max) from 512 to 503 V/s. Increasing the phase angle of the passive fiber membrane impedence (Z(m)) increases the phase delay between I-ma and I-ep, thereby increasing phi(epp) which in turn slows down propagation and increases V-max....

  9. Satellite cell depletion prevents fiber hypertrophy in skeletal muscle.

    Science.gov (United States)

    Egner, Ingrid M; Bruusgaard, Jo C; Gundersen, Kristian

    2016-08-15

    The largest mammalian cells are the muscle fibers, and they have multiple nuclei to support their large cytoplasmic volumes. During hypertrophic growth, new myonuclei are recruited from satellite stem cells into the fiber syncytia, but it was recently suggested that such recruitment is not obligatory: overload hypertrophy after synergist ablation of the plantaris muscle appeared normal in transgenic mice in which most of the satellite cells were abolished. When we essentially repeated these experiments analyzing the muscles by immunohistochemistry and in vivo and ex vivo imaging, we found that overload hypertrophy was prevented in the satellite cell-deficient mice, in both the plantaris and the extensor digitorum longus muscles. We attribute the previous findings to a reliance on muscle mass as a proxy for fiber hypertrophy, and to the inclusion of a significant number of regenerating fibers in the analysis. We discuss that there is currently no model in which functional, sustainable hypertrophy has been unequivocally demonstrated in the absence of satellite cells; an exception is re-growth, which can occur using previously recruited myonuclei without addition of new myonuclei. PMID:27531949

  10. Calcium sensitivity of human single muscle fibers following plyometric training

    OpenAIRE

    Malisoux, Laurent; Francaux, Marc; Nielens, Henri; Renard, Patricia; Lebacq, Jean; Theisen, Daniel

    2006-01-01

    PURPOSE: To study the effect of plyometric training on Ca2+ sensitivity and the influence of troponin T (TnT) isoforms on Ca2+ -activation properties in skinned human muscle fibers. METHODS: Biopsies were obtained from the vastus lateralis of eight men before and after the training period. Chemically skinned fibers were evaluated regarding their Ca2+ -activation properties and were classified according to their myosin heavy chain (MHC) contents and analyzed regarding their slow and fast TnT i...

  11. Severely Atrophic Human Muscle Fibers With Nuclear Misplacement Survive Many Years of Permanent Denervation.

    Science.gov (United States)

    Carraro, Ugo; Kern, Helmut

    2016-06-13

    Likewise in rodents, after complete spinal cord injury (SCI) the lower motor neuron (LMN) denervated human muscle fibers lose completely the myofibrillar apparatus and the coil distribution of myonuclei that are relocated in groups (nuclear clumps) in the center of severely atrophic muscle fibers. Up to two years of LMN denervation the muscle fibers with nuclear clumps are very seldom, but in this cohort of patients the severely atrophic muscle fibers are frequent in muscle biopsies harvested three to six years after SCI. Indeed, the percentage increased to 27 ± 9% (pbehavior in long term denervated muscle fibers. PMID:27478559

  12. Striated muscle fiber size, composition and capillary density in diabetes in relation to neuropathy and muscle strength

    DEFF Research Database (Denmark)

    Andreassen, Christer Swan; Jensen, Jacob Malte; Jakobsen, Johannes; Ulhøi, Benedicte Parm; Andersen, Henning

    2014-01-01

    OBJECTIVE: Diabetic polyneuropathy (DPN) leads to progressive loss of muscle strength in the lower extremities due to muscular atrophy. Changes in vascularization occur in diabetic striated muscle; however, the relationship between these changes and DPN is as yet unexplored. The aim of the present...... study was to evaluate histologic properties and capillarization of diabetic skeletal muscle in relation to DPN and muscle strength. METHODS: Twenty type 1 and 20 type 2 diabetic (T1D and T2D, respectively) patients underwent biopsy of the gastrocnemic muscle, isokinetic dynamometry at the ankle...... between muscle fiber diameter, muscle fiber type distribution, or capillary density and degree of neuropathy or muscle strength for either patient group. Muscle fiber diameter and the proportion of Type II fibers were greater for T1D patients than both T2D patients and controls. The T2D patients had fewer...

  13. Biochemical adaptations of antigravity muscle fibers to disuse atrophy

    Science.gov (United States)

    Booth, F. W.

    1978-01-01

    Studies are presented in four parts of this report. The four parts include; (1) studies to gain information on the molecular basis of atrophy by antigravity muscle; (2) studies on the work capacity of antigravity muscles during atrophy and during recovery from atrophy; (3) studies on recovery of degenerated antigravity fibers after removal of hind-limb casts; and (4) studies on the atrophy and recovery of bone. The philosophy of these studies was to identify the time sequence of events in the soleus muscle of the rat following immobilization of the hind limbs, so that the length of the soleus muscle within the fixed limb is less than its resting length. In two separate studies, no decline in the weight of the soleus muscle could be detected during the first 72 hours of limb immobilization.

  14. Overexpression of SMPX in adult skeletal muscle does not change skeletal muscle fiber type or size.

    Directory of Open Access Journals (Sweden)

    Einar Eftestøl

    Full Text Available Mechanical factors such as stretch are thought to be important in the regulation of muscle phenotype. Small muscle protein X-linked (SMPX is upregulated by stretch in skeletal muscle and has been suggested to serve both as a transcription factor and a mechanosensor, possibly giving rise to changes in both fiber size and fiber type. We have used in vivo confocal imaging to study the subcellular localization of SMPX in skeletal muscle fibers of adult rats using a SMPX-EGFP fusion protein. The fusion protein was localized predominantly in repetitive double stripes flanking the Z-disc, and was excluded from all nuclei. This localization would be consistent with SMPX being a mechanoreceptor, but not with SMPX playing a role as a transcription factor. In vivo overexpression of ectopic SMPX in skeletal muscle of adult mice gave no significant changes in fiber type distribution or cross sectional area, thus a role of SMPX in regulating muscle phenotype remains unclear.

  15. Pax7 Shows Higher Satellite Cell Frequencies and Concentrations Within Intrafusal Fibers of Muscle Spindles

    OpenAIRE

    Kirkpatrick, Lisa J.; Allouh, Mohammed Z.; Nightingale, Chantale N.; Devon, Heidi G.; Yablonka-Reuveni, Zipora; Rosser, Benjamin W. C.

    2008-01-01

    Intrafusal fibers within muscle spindles make up a small subpopulation of muscle fibers. These proprioceptive fibers differ from most extrafusal fibers because, even in maturity, their diameters remain small, and they retain expression of developmental myosins. Although both extrafusal and intrafusal fibers contain satellite cells (SCs), comparatively little is known about intrafusal SCs. Analyzing chicken fast-phasic posterior (PLD) and slow-tonic anterior (ALD) latissimus dorsi muscles, we ...

  16. Myriocin prevents muscle ceramide accumulation but not muscle fiber atrophy during short-term mechanical unloading.

    Science.gov (United States)

    Salaun, Erwann; Lefeuvre-Orfila, Luz; Cavey, Thibault; Martin, Brice; Turlin, Bruno; Ropert, Martine; Loreal, Olivier; Derbré, Frédéric

    2016-01-15

    Bedridden patients in intensive care unit or after surgery intervention commonly develop skeletal muscle weakness. The latter is promoted by a variety of prolonged hospitalization-associated conditions. Muscle disuse is the most ubiquitous and contributes to rapid skeletal muscle atrophy and progressive functional strength reduction. Disuse causes a reduction in fatty acid oxidation, leading to its accumulation in skeletal muscle. We hypothesized that muscle fatty acid accumulation could stimulate ceramide synthesis and promote skeletal muscle weakness. Therefore, the present study was designed to determine the effects of sphingolipid metabolism on skeletal muscle atrophy induced by 7 days of disuse. For this purpose, male Wistar rats were treated with myriocin, an inhibitor of de novo synthesis of ceramides, and subjected to hindlimb unloading (HU) for 7 days. Soleus muscles were assayed for fiber diameter, ceramide levels, protein degradation, and apoptosis signaling. Serum and liver were removed to evaluate the potential hepatoxicity of myriocin treatment. We found that HU increases content of saturated C16:0 and C18:0 ceramides and decreases soleus muscle weight and fiber diameter. HU increased the level of polyubiquitinated proteins and induced apoptosis in skeletal muscle. Despite a prevention of C16:0 and C18:0 muscle accumulation, myriocin treatment did not prevent skeletal muscle atrophy and concomitant induction of apoptosis and proteolysis. Moreover, myriocin treatment increased serum transaminases and induced hepatocyte necrosis. These data highlight that inhibition of de novo synthesis of ceramides during immobilization is not an efficient strategy to prevent skeletal muscle atrophy and exerts adverse effects like hepatotoxicity. PMID:26542521

  17. Polarization-sensitive optical projection tomography for muscle fiber imaging.

    Science.gov (United States)

    Fang, Mengjie; Dong, Di; Zeng, Chaoting; Liang, Xiao; Yang, Xin; Arranz, Alicia; Ripoll, Jorge; Hui, Hui; Tian, Jie

    2016-01-01

    Optical projection tomography (OPT) is a tool used for three-dimensional imaging of millimeter-scale biological samples, with the advantage of exhibiting isotropic resolution typically in the micron range. OPT can be divided into two types: transmission OPT (tOPT) and emission OPT (eOPT). Compared with eOPT, tOPT discriminates different tissues based on their absorption coefficient, either intrinsic or after specific staining. However, it fails to distinguish muscle fibers whose absorption coefficients are similar to surrounding tissues. To circumvent this problem, in this article we demonstrate a polarization sensitive OPT system which improves the detection and 3D imaging of muscle fibers by using polarized light. We also developed image acquisition and processing protocols that, together with the system, enable the clear visualization of muscles. Experimental results show that the muscle fibers of diaphragm and stomach, difficult to be distinguished in regular tOPT, were clearly displayed in our system, proving its potential use. Moreover, polarization sensitive OPT was fused with tOPT to investigate the stomach tissue comprehensively. Future applications of polarization sensitive OPT could be imaging other fiber-like structures such as myocardium or other tissues presenting high optical anisotropy. PMID:26752330

  18. Fiber optic biofluorometer for physiological research on muscle slices

    Science.gov (United States)

    Belz, Mathias; Dendorfer, Andreas; Werner, Jan; Lambertz, Daniel; Klein, Karl-Friedrich

    2016-03-01

    A focus of research in cell physiology is the detection of Ca2+, NADH, FAD, ATPase activity or membrane potential, only to name a few, in muscle tissues. In this work, we report on a biofluorometer using ultraviolet light emitting diodes (UV-LEDs), optical fibers and two photomultipliers (PMTs) using synchronized fluorescence detection with integrated background correction to detect free calcium, Ca2+, in cardiac muscle tissue placed in a horizontal tissue bath and a microscope setup. Fiber optic probes with imaging optics have been designed to transport excitation light from the biofluorometer's light output to a horizontal tissue bath and to collect emission light from a tissue sample of interest to two PMTs allowing either single excitation / single emission or ratiometric, dual excitation / single emission or single excitation / dual emission fluorescence detection of indicator dyes or natural fluorophores. The efficient transport of light from the excitation LEDs to the tissue sample, bleaching effects of the excitation light in both, polymer and fused silica-based fibers will be discussed. Furthermore, a new approach to maximize light collection of the emission light using high NA fibers and high NA coupling optics will be shown. Finally, first results on Ca2+ measurements in cardiac muscle slices in a traditional microscope setup and a horizontal tissue bath using fiber optic probes will be introduced and discussed.

  19. Muscle Activity and Muscle Agrin Regulate the Organization of Cytoskeletal Proteins and Attached Acetylcholine Receptor (Achr) Aggregates in Skeletal Muscle Fibers

    OpenAIRE

    Bezakova, Gabriela; Lømo, Terje

    2001-01-01

    In innervated skeletal muscle fibers, dystrophin and β-dystroglycan form rib-like structures (costameres) that appear as predominantly transverse stripes over Z and M lines. Here, we show that the orientation of these stripes becomes longitudinal in denervated muscles and transverse again in denervated electrically stimulated muscles. Skeletal muscle fibers express nonneural (muscle) agrin whose function is not well understood. In this work, a single application of ≥10 nM purified recombinant...

  20. Effect of swim exercise training on human muscle fiber function

    Science.gov (United States)

    Fitts, R. H.; Costill, D. L.; Gardetto, P. R.

    1989-01-01

    The effect of swim exercise training on the human muscle fiber function was investigated in swimmers trained in a typical collegiate swim-training program followed by an intensified 10-day training period. The measured parameters included the peak tension (P0), negative log molar Ca(2+) concentration (pCa)-force, and maximal shortening speed (Vmax) of the slow-twitch type I and fast-twitch type II fibers obtained by biopsy from the deltoid muscle. The P0 values were found to be not altered after either the training or the 10-day intensive program. The type I fibers from the trained swimmers showed pCa-force curves shifted to the right, such that higher free Ca(2+) levels were required to elicit a given percent of P0. The training program significantly increased the Vmax in the type I fibers and decreased that of the type II fibers, and the 10-day intensive training produced a further significant decrease of the type II fibers.

  1. Thin Filament-Reconstituted Skinned Muscle Fibers for the Study of Muscle Physiology

    OpenAIRE

    Hideaki Fujita; Satoshi Kurihara; Norio Fukuda; Yoshikazu Tsukasaki; Sayaka Higuchi

    2011-01-01

    We review the use of thin filament-reconstituted muscle fibers in the study of muscle physiology. Thin filament extraction and reconstitution protocol is a powerful technique to study the role of each component of the thin filament. It is also useful for studying the properties of genetically modified molecules such as actin and tropomyosin. We also review the combination of this protocol with sinusoidal analysis, which will provide a solid technique for determining the effect of regulatory p...

  2. MR relaxation times and fiber type predominance of the psoas and multifidus muscle

    International Nuclear Information System (INIS)

    MR relaxation times, fiber composition, nonmyofiber space, water content, and fat content of human psoas and multifidus muscle samples of 10 male cadavers were studied in vitro. The T1 and T2 relaxation times of multifidus muscle were significantly longer than those of the psoas muscle. On average, type 1 fibers (slow fibers with a small cross-sectional diameter) predominated in both muscles. There was no correlation between the relative mass of type 1 or 2 fibers (fast fibers with a large cross-sectional diameter) or nonmyofiber space and the relaxation times. The quantity of fat in the muscle did not correlate with the relaxation times either. (orig.)

  3. Muscle fiber type specific induction of slow myosin heavy chain 2 gene expression by electrical stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Crew, Jennifer R.; Falzari, Kanakeshwari [Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 (United States); DiMario, Joseph X., E-mail: joseph.dimario@rosalindfranklin.edu [Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 (United States)

    2010-04-01

    Vertebrate skeletal muscle fiber types are defined by a broad array of differentially expressed contractile and metabolic protein genes. The mechanisms that establish and maintain these different fiber types vary throughout development and with changing functional demand. Chicken skeletal muscle fibers can be generally categorized as fast and fast/slow based on expression of the slow myosin heavy chain 2 (MyHC2) gene in fast/slow muscle fibers. To investigate the cellular and molecular mechanisms that control fiber type formation in secondary or fetal muscle fibers, myoblasts from the fast pectoralis major (PM) and fast/slow medial adductor (MA) muscles were isolated, allowed to differentiate in vitro, and electrically stimulated. MA muscle fibers were induced to express the slow MyHC2 gene by electrical stimulation, whereas PM muscle fibers did not express the slow MyHC2 gene under identical stimulation conditions. However, PM muscle fibers did express the slow MyHC2 gene when electrical stimulation was combined with inhibition of inositol triphosphate receptor (IP3R) activity. Electrical stimulation was sufficient to increase nuclear localization of expressed nuclear-factor-of-activated-T-cells (NFAT), NFAT-mediated transcription, and slow MyHC2 promoter activity in MA muscle fibers. In contrast, both electrical stimulation and inhibitors of IP3R activity were required for these effects in PM muscle fibers. Electrical stimulation also increased levels of peroxisome-proliferator-activated receptor-{gamma} co-activator-1 (PGC-1{alpha}) protein in PM and MA muscle fibers. These results indicate that MA muscle fibers can be induced by electrical stimulation to express the slow MyHC2 gene and that fast PM muscle fibers are refractory to stimulation-induced slow MyHC2 gene expression due to fast PM muscle fiber specific cellular mechanisms involving IP3R activity.

  4. Muscle fiber type specific induction of slow myosin heavy chain 2 gene expression by electrical stimulation

    International Nuclear Information System (INIS)

    Vertebrate skeletal muscle fiber types are defined by a broad array of differentially expressed contractile and metabolic protein genes. The mechanisms that establish and maintain these different fiber types vary throughout development and with changing functional demand. Chicken skeletal muscle fibers can be generally categorized as fast and fast/slow based on expression of the slow myosin heavy chain 2 (MyHC2) gene in fast/slow muscle fibers. To investigate the cellular and molecular mechanisms that control fiber type formation in secondary or fetal muscle fibers, myoblasts from the fast pectoralis major (PM) and fast/slow medial adductor (MA) muscles were isolated, allowed to differentiate in vitro, and electrically stimulated. MA muscle fibers were induced to express the slow MyHC2 gene by electrical stimulation, whereas PM muscle fibers did not express the slow MyHC2 gene under identical stimulation conditions. However, PM muscle fibers did express the slow MyHC2 gene when electrical stimulation was combined with inhibition of inositol triphosphate receptor (IP3R) activity. Electrical stimulation was sufficient to increase nuclear localization of expressed nuclear-factor-of-activated-T-cells (NFAT), NFAT-mediated transcription, and slow MyHC2 promoter activity in MA muscle fibers. In contrast, both electrical stimulation and inhibitors of IP3R activity were required for these effects in PM muscle fibers. Electrical stimulation also increased levels of peroxisome-proliferator-activated receptor-γ co-activator-1 (PGC-1α) protein in PM and MA muscle fibers. These results indicate that MA muscle fibers can be induced by electrical stimulation to express the slow MyHC2 gene and that fast PM muscle fibers are refractory to stimulation-induced slow MyHC2 gene expression due to fast PM muscle fiber specific cellular mechanisms involving IP3R activity.

  5. Induction of GLUT-1 protein in adult human skeletal muscle fibers

    DEFF Research Database (Denmark)

    Gaster, M; Franch, J; Staehr, P;

    2000-01-01

    Prompted by our recent observations that GLUT-1 is expressed in fetal muscles, but not in adult muscle fibers, we decided to investigate whether GLUT-1 expression could be reactivated. We studied different stimuli concerning their ability to induce GLUT-1 expression in mature human skeletal muscle...... fibers. Metabolic stress (obesity, non-insulin-dependent diabetes mellitus), contractile activity (training), and conditions of de- and reinnervation (amyotrophic lateral sclerosis) could not induce GLUT-1 expression in human muscle fibers. However, regenerating muscle fibers in polymyositis expressed...... GLUT-1. In contrast to GLUT-1, GLUT-4 was expressed in all investigated muscle fibers. Although the significance of GLUT-1 in adult human muscle fibers appears limited, GLUT-1 may be of importance for the glucose supplies in immature and regenerating muscle....

  6. Effect of one stretch a week applied to the immobilized soleus muscle on rat muscle fiber morphology

    Directory of Open Access Journals (Sweden)

    Gomes A.R.S.

    2004-01-01

    Full Text Available We determined the effect of stretching applied once a week to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Twenty-six male Wistar rats weighing 269 ± 26 g were divided into three groups. Group I, the left soleus was immobilized in the shortened position for 3 weeks; group II, the soleus was immobilized in the shortened position and stretched once a week for 3 weeks; group III, the soleus was submitted only to stretching once a week for 3 weeks. The medial part of the soleus muscle was frozen for histology and muscle fiber area evaluation and the lateral part was used for the determination of number and length of serial sarcomeres. Soleus muscle submitted only to immobilization showed a reduction in weight (44 ± 6%, P = 0.002, in serial sarcomere number (23 ± 15% and in cross-sectional area of the fibers (37 ± 31%, P < 0.001 compared to the contralateral muscles. The muscle that was immobilized and stretched showed less muscle fiber atrophy than the muscles only immobilized (P < 0.05. Surprisingly, in the muscles submitted only to stretching, fiber area was decreased compared to the contralateral muscle (2548 ± 659 vs 2961 ± 806 µm², respectively, P < 0.05. In conclusion, stretching applied once a week for 40 min to the soleus muscle immobilized in the shortened position was not sufficient to prevent the reduction of muscle weight and of serial sarcomere number, but provided significant protection against muscle fiber atrophy. In contrast, stretching normal muscles once a week caused a reduction in muscle fiber area.

  7. Muscle Extracellular Matrix Applies a Transverse Stress on Fibers With Axial Strain

    OpenAIRE

    Smith, Lucas R.; Gerace-Fowler, Lewis; Lieber, Richard L.

    2011-01-01

    It is widely assumed that skeletal muscle contraction is isovolumic. This assumption has been verified at the single fiber and at the myofibril level. Model development and mechanical analyses often exploit this assumption when investigating skeletal muscle and evaluating muscle mechanical properties. This communication describes a method whereby individual muscle fibers and bundles of fibers, which include their constituent extracellular matrix (ECM), were tested to define the change in volu...

  8. Characteristics of Skeletal Muscle Fibers of SOD1 Knockout Mice

    OpenAIRE

    Hiroshi Nagahisa; Kazuma Okabe; Yoshihito Iuchi; Junichi Fujii; Hirofumi Miyata

    2016-01-01

    Cu/Zn superoxide dismutase (SOD1) knockout (KO) mice are known as an aging model in some aspects, but the damage and regeneration process of each fiber type have not been sufficiently studied. In this study, we investigated the damage and satellite cell state of the gastrocnemius muscle in SOD1 KO mice (6 months old) using immunohistochemical staining and real-time RT-PCR. The proportion of central nuclei-containing Type IIx/b fibers in the deep and superficial portions of the gastrocnemius m...

  9. Muscle Fiber Type Specific Induction of Slow Myosin Heavy Chain 2 Gene Expression by Electrical Stimulation

    OpenAIRE

    Crew, Jennifer R.; Falzari, Kanakeshwari; DiMario, Joseph X.

    2010-01-01

    Vertebrate skeletal muscle fiber types are defined by a broad array of differentially expressed contractile and metabolic protein genes. The mechanisms that establish and maintain these different fiber types vary throughout development and with changing functional demand. Chicken skeletal muscle fibers can be generally categorized as fast and fast/slow based on expression of the slow myosin heavy chain 2 (MyHC2) gene in fast/slow muscle fibers. To investigate the cellular and molecular mechan...

  10. Ultrastructure of striated muscle fibers in the middle third of the human esophagus

    OpenAIRE

    Faussone-Pellegrini, M.S; Cortesini, C.

    1986-01-01

    Striated muscle fibers and .their spatial relationship to smooth muscle cells have been studied in the middle third of human esophagus. Biopsies were obtained from 3 patients during surgery. In both the circular and longitudinal layers, the muscle coat of this transition zone was composed of fascicles of uniform dimensioi~ (100-200 pm of diameter); some of these bundles were made up of striated muscle fibers, others were pure bundles of smooth muscle cells and ...

  11. Single muscle fiber gene expression in human skeletal muscle: validation of internal control with exercise

    International Nuclear Information System (INIS)

    Reverse transcription and real-time PCR have become the method of choice for the detection of low-abundance mRNA transcripts obtained from small human muscle biopsy samples. GAPDH, β-actin, β-2M, and 18S rRNA are widely employed as endogenous control genes, with the assumption that their expression is unregulated and constant for given experimental conditions. The aim of this study was to determine if mRNA transcripts could be performed on isolated human single muscle fibers and to determine reliable housekeeping genes (HKGs) using quantitative gene expression protocols at rest and in response to an acute exercise bout. Muscle biopsies were obtained from the gastrocnemius of three adult males before, immediately after, and 4 h following 30 min of treadmill running at 70% of VO2max. A total of 40 single fibers (MHC I and IIa) were examined for GAPDH, β-actin, β-2M, and 18S rRNA using quantitative RT-PCR and SYBR Green detection. All analyzed single fiber segments showed ribosomal RNA (28S/18S). No degradation or additional bands below ribosomal were detected (rRNA ratio 1.5-1.8). Also, no high or low-molecular weight genomic DNA contamination was observed. For each housekeeping gene the duplicate average SD was ±0.13 with a CV of 0.58%. Stable expression of GAPDH was observed at all time points for each fiber type (MHC I and IIa). Inconsistent expression of β-actin, β-2M, and 18S rRNA was observed during the post-exercise time points for each fiber type. These data indicate that successful extraction of high quality RNA from human single muscle fibers along with quantification of mRNA of selected genes can be performed. Furthermore, exercise does influence the expression of certain HKGs with GAPDH being the most stable

  12. Changes in skeletal muscle biochemistry and histology relative to fiber type in rats with heart failure

    Science.gov (United States)

    Delp, M. D.; Duan, C.; Mattson, J. P.; Musch, T. I.

    1997-01-01

    One of the primary consequences of left ventricular dysfunction (LVD) after myocardial infarction is a decrement in exercise capacity. Several factors have been hypothesized to account for this decrement, including alterations in skeletal muscle metabolism and aerobic capacity. The purpose of this study was to determine whether LVD-induced alterations in skeletal muscle enzyme activities, fiber composition, and fiber size are 1) generalized in muscles or specific to muscles composed primarily of a given fiber type and 2) related to the severity of the LVD. Female Wistar rats were divided into three groups: sham-operated controls (n = 13) and rats with moderate (n = 10) and severe (n = 7) LVD. LVD was surgically induced by ligating the left main coronary artery and resulted in elevations (P muscle composed of type IIB fibers but did not modify fiber composition or size of any muscle studied. However, severe LVD diminished the activity of enzymes involved in terminal and beta-oxidation in muscles composed primarily of type I fibers, type IIA fibers, and type IIB fibers. In addition, severe LVD induced a reduction in the activity of PFK in type IIB muscle, a 10% reduction in the percentage of type IID/X fibers, and a corresponding increase in the portion of type IIB fibers. Atrophy of type I fibers, type IIA fibers, and/or type IIB fibers occurred in soleus and plantaris muscles of rats with severe LVD. These data indicate that rats with severe LVD after myocardial infarction exhibit 1) decrements in mitochondrial enzyme activities independent of muscle fiber composition, 2) a reduction in PFK activity in type IIB muscle, 3) transformation of type IID/X to type IIB fibers, and 4) atrophy of type I, IIA, and IIB fibers.

  13. Direct evidence of fiber type-dependent GLUT-4 expression in human skeletal muscle

    DEFF Research Database (Denmark)

    Gaster, M; Poulsen, P; Handberg, A;

    2000-01-01

    GLUT-4 expression in individual fibers of human skeletal muscles in younger and older adults was studied. Furthermore, the dependency of insulin-stimulated glucose uptake on fiber type distribution was investigated. Fiber type distribution was determined in cryosections of muscle biopsies from 8...... slow fibers in the young (r = -0.45, P > 0.25) or in the elderly (r = 0. 11, P > 0.75) subjects. In conclusion, in human skeletal muscle, GLUT-4 expression is fiber type dependent and decreases with age, particularly in fast muscle fibers....... younger (29 yr) and 8 older (64 yr) healthy subjects, and estimates of GLUT-4 expression in individual fibers were obtained by combining immunohistochemistry and stereology. GLUT-4 was more abundantly expressed in slow compared with fast muscle fibers in both younger (P < 0.007) and older (P < 0. 001...

  14. Reduced force of diaphragm muscle fibers in patients with chronic thromboembolic pulmonary hypertension.

    Science.gov (United States)

    Manders, Emmy; Bonta, Peter I; Kloek, Jaap J; Symersky, Petr; Bogaard, Harm-Jan; Hooijman, Pleuni E; Jasper, Jeff R; Malik, Fady I; Stienen, Ger J M; Vonk-Noordegraaf, Anton; de Man, Frances S; Ottenheijm, Coen A C

    2016-07-01

    Patients with pulmonary hypertension (PH) suffer from inspiratory muscle weakness. However, the pathophysiology of inspiratory muscle dysfunction in PH is unknown. We hypothesized that weakness of the diaphragm, the main inspiratory muscle, is an important contributor to inspiratory muscle dysfunction in PH patients. Our objective was to combine ex vivo diaphragm muscle fiber contractility measurements with measures of in vivo inspiratory muscle function in chronic thromboembolic pulmonary hypertension (CTEPH) patients. To assess diaphragm muscle contractility, function was studied in vivo by maximum inspiratory pressure (MIP) and ex vivo in diaphragm biopsies of the same CTEPH patients (N = 13) obtained during pulmonary endarterectomy. Patients undergoing elective lung surgery served as controls (N = 15). Muscle fiber cross-sectional area (CSA) was determined in cryosections and contractility in permeabilized muscle fibers. Diaphragm muscle fiber CSA was not significantly different between control and CTEPH patients in both slow-twitch and fast-twitch fibers. Maximal force-generating capacity was significantly lower in slow-twitch muscle fibers of CTEPH patients, whereas no difference was observed in fast-twitch muscle fibers. The maximal force of diaphragm muscle fibers correlated significantly with MIP. The calcium sensitivity of force generation was significantly reduced in fast-twitch muscle fibers of CTEPH patients, resulting in a ∼40% reduction of submaximal force generation. The fast skeletal troponin activator CK-2066260 (5 μM) restored submaximal force generation to levels exceeding those observed in control subjects. In conclusion, diaphragm muscle fiber contractility is hampered in CTEPH patients and contributes to the reduced function of the inspiratory muscles in CTEPH patients. PMID:27190061

  15. Persistent muscle fiber regeneration in long term denervation. Past, present, future

    OpenAIRE

    Carraro, Ugo; Boncompagni, Simona; Gobbo, Valerio; Rossini, Katia; Zampieri, Sandra; Mosole, Simone; Ravara, Barbara; Nori, Alessandra; Stramare, Roberto; Ambrosio, Francesco; Piccione, Francesco; Masiero, Stefano; Vindigni, Vincenzo; Gargiulo, Paolo; Protasi, Feliciano

    2015-01-01

    Despite the ravages of long term denervation there is structural and ultrastructural evidence for survival of muscle fibers in mammals, with some fibers surviving at least ten months in rodents and 3–6 years in humans. Further, in rodents there is evidence that muscle fibers may regenerate even after repeated damage in the absence of the nerve, and that this potential is maintained for several months after denervation. While in animal models permanently denervated muscle sooner or later loses...

  16. UNLOADED SHORTENING VELOCITY AND MYOSIN HEAVY CHAIN VARIATIONS IN HUMAN LARYNGEAL MUSCLE FIBERS

    OpenAIRE

    Sciote, James J.; Morris, Terence J.; Horton, Michael J.; Brandon, Carla A.; Rosen, Clark

    2002-01-01

    Myosin description in human laryngeal muscles is incomplete, but evidence suggests the presence of type I, IIA, IIX, and tonic myosin heavy chain (MHC) fibers. This study describes the unloaded shortening velocity (V0) of chemically skinned laryngeal muscle fibers measured by the slack test method in relation to MHC content. Skeletal fibers from human laryngeal and limb muscle biopsy specimens were obtained for determination of V0, and subsequently, glycerol–sodium dodecyl sulfate–polyacrylam...

  17. Persistent muscle fiber regeneration in long term denervation. Past, present, future

    OpenAIRE

    Ugo Carraro; Simona Boncompagni; Valerio Gobbo; Katia Rossini; Sandra Zampieri; Simone Mosole; Barbara Ravara; Alessandra Nori; Roberto Stramare; Francesco Ambrosio; Francesco Piccione; Stefano Masiero; Vincenzo Vindigni; Paolo Gargiulo; Feliciano Protasi

    2015-01-01

    Despite the ravages of long term denervation there is structural and ultrastructural evidence for survival of muscle fibers in mammals, with some fibers surviving at least ten months in rodents and 3-6 years in humans. Further, in rodents there is evidence that muscle fibers may regenerate even after repeated damage in the absence of the nerve, and that this potential is maintained for several months after denervation. While in animal models permanently denervated muscle sooner or later loses...

  18. Evidence for ACTN3 as a Speed Gene in Isolated Human Muscle Fibers.

    Directory of Open Access Journals (Sweden)

    Siacia Broos

    Full Text Available To examine the effect of α-actinin-3 deficiency due to homozygosity for the ACTN3 577X-allele on contractile and morphological properties of fast muscle fibers in non-athletic young men.A biopsy was taken from the vastus lateralis of 4 RR and 4 XX individuals to test for differences in morphologic and contractile properties of single muscle fibers. The cross-sectional area of the fiber and muscle fiber composition was determined using standard immunohistochemistry analyses. Skinned single muscle fibers were subjected to active tests to determine peak normalized force (P0, maximal unloading velocity (V0 and peak power. A passive stretch test was performed to calculate Young's Modulus and hysteresis to assess fiber visco-elasticity.No differences were found in muscle fiber composition. The cross-sectional area of type IIa and IIx fibers was larger in RR compared to XX individuals (P<0.001. P0 was similar in both groups over all fiber types. A higher V0 was observed in type IIa fibers of RR genotypes (P<0.001 but not in type I fibers. The visco-elasticity as determined by Young's Modulus and hysteresis was unaffected by fiber type or genotype.The greater V0 and the larger fast fiber CSA in RR compared to XX genotypes likely contribute to enhanced whole muscle performance during high velocity contractions.

  19. HDAC4 Regulates Muscle Fiber Type-Specific Gene Expression Programs

    OpenAIRE

    Cohen, Todd J.; Choi, Moon-Chang; Kapur, Meghan; Lira, Vitor A.; Yan, Zhen; Yao, Tso-Pang

    2015-01-01

    Fiber type-specific programs controlled by the transcription factor MEF2 dictate muscle functionality. Here, we show that HDAC4, a potent MEF2 inhibitor, is predominantly localized to the nuclei in fast/glycolytic fibers in contrast to the sarcoplasm in slow/oxidative fibers. The cytoplasmic localization is associated with HDAC4 hyper-phosphorylation in slow/oxidative-fibers. Genetic reprogramming of fast/glycolytic fibers to oxidative fibers by active CaMKII or calcineurin leads to increased...

  20. Computational Model of Cellular Metabolic Dynamics in Skeletal Muscle Fibers during Moderate Intensity Exercise

    OpenAIRE

    Li, Yanjun; Lai, Nicola; Kirwan, John P; Saidel, Gerald M.

    2012-01-01

    Human skeletal muscles have different fiber types with distinct metabolic functions and physiological properties. The quantitative metabolic responses of muscle fibers to exercise provide essential information for understanding and modifying the regulatory mechanisms of skeletal muscle. Since in vivo data from skeletal muscle during exercise is limited, a computational, physiologically based model has been developed to quantify the dynamic metabolic responses of many key chemical species. Thi...

  1. Identification of sarcolemma-associated antigens with differential distributions on fast and slow skeletal muscle fibers

    OpenAIRE

    1987-01-01

    We have identified three sarcolemma-associated antigens, including two antigens that are differentially distributed on skeletal muscle fibers of the fast, fast/slow, and slow types. Monoclonal antibodies were prepared using partially purified membranes of adult chicken skeletal muscles as immunogens and were used to characterize three antigens associated with the sarcolemma of muscle fibers. Immunofluorescence staining of cryosections of adult and embryonic chicken muscles showed that two of ...

  2. Denervation Causes Fiber Atrophy and Myosin Heavy Chain Co-Expression in Senescent Skeletal Muscle

    OpenAIRE

    Sharon L Rowan; Rygiel, Karolina; Purves-Smith, Fennigje M.; Solbak, Nathan M.; Turnbull, Douglas M.; Hepple, Russell T.

    2012-01-01

    Although denervation has long been implicated in aging muscle, the degree to which it is causes the fiber atrophy seen in aging muscle is unknown. To address this question, we quantified motoneuron soma counts in the lumbar spinal cord using choline acetyl transferase immunhistochemistry and quantified the size of denervated versus innervated muscle fibers in the gastrocnemius muscle using the in situ expression of the denervation-specific sodium channel, Nav1.5, in young adult (YA) and senes...

  3. Intracellular Ca2+-handling differs markedly between intact human muscle fibers and myotubes

    OpenAIRE

    Olsson, Karl; Cheng, Arthur J.; Alam, Seher; Al-Ameri, Mamdoh; Rullman, Eric; Westerblad, Håkan; Lanner, Johanna T.; Bruton, Joseph D.; Gustafsson, Thomas

    2015-01-01

    Background In skeletal muscle, intracellular Ca2+ is an important regulator of contraction as well as gene expression and metabolic processes. Because of the difficulties to obtain intact human muscle fibers, human myotubes have been extensively employed for studies of Ca2+-dependent processes in human adult muscle. Despite this, it is unknown whether the Ca2+-handling properties of myotubes adequately represent those of adult muscle fibers. Methods To enable a comparison of the Ca2+-handling...

  4. Functional, structural, and chemical changes in myosin associated with hydrogen peroxide treatment of skeletal muscle fibers

    OpenAIRE

    Prochniewicz, Ewa; Lowe, Dawn A.; Spakowicz, Daniel J; Higgins, LeeAnn; O'Conor, Kate; Thompson, LaDora V.; Deborah A Ferrington; Thomas, David D.

    2007-01-01

    To understand the molecular mechanism of oxidation-induced inhibition of muscle contractility, we have studied the effects of hydrogen peroxide on permeabilized rabbit psoas muscle fibers, focusing on changes in myosin purified from these fibers. Oxidation by 5 mM peroxide decreased fiber contractility (isometric force and shortening velocity) without significant changes in the enzymatic activity of myofibrils and isolated myosin. The inhibitory effects were reversed by treating fibers with d...

  5. [Physiological features of the wing muscle fibers of Locusta migratoria locusts].

    Science.gov (United States)

    Grigor'ev, V V

    1980-01-01

    In bifunctional dorsoventral muscle M-120 of the locust Locusta migratoria migratorioides three groups of fibers have been found which differ with respect to their electrophysiological properties. The evoked fast potentials in the fibers of caudal portion differed from fast potentials observed in the fibers of rostral and intermediate portions of the muscle. In the fibers of the caudal and intermediate portions of muscle, not only fast, but other depolarization potentials were also recorded which differ in the amplitude and duration, as well as the inhibitory postsynaptic potentials. It was shown that fibers in these three parts of the muscle differ in their voltage-current properties. It is concluded that different types of potentials are due to peculiarities of innervation and to structural heterogeneity of muscle fibers. PMID:6247866

  6. Muscle-specific integrins in masseter muscle fibers of chimpanzees: an immunohistochemical study.

    Directory of Open Access Journals (Sweden)

    Gianluigi Vaccarino

    2010-05-01

    Full Text Available Most notably, recent comparative genomic analyses strongly indicate that the marked differences between modern human and chimpanzees are likely due more to changes in gene regulation than to modifications of the genes. The most peculiar aspect of hominoid karyotypes is that human have 46 chromosomes whereas gorillas and chimpanzees have 48. Interestingly, human and chimpanzees do share identical inversions on chromosome 7 and 9 that are not evident in the gorilla karyotype. Thus, the general phylogeny suggests that humans and chimpanzees are sister taxa; based on this, it seems that human-chimpanzee sequence similarity is an astonishing 99%. At this purpose, of particular interest is the inactivation of the myosin heavy chain 16 (MYH16 gene, most prominently expressed in the masticatory muscle of mammals. It has been showed that the loss of this gene in humans may have resulted in smaller masticatory muscle and consequential changes to cranio-facial morphology and expansion of the human brain case. Powerful masticatory muscles are found in most primates; contrarily, in both modern and fossil member Homo, these muscles are considerably smaller. The evolving hominid masticatory apparatus shifted towards a pattern of gracilization nearly simultaneously with accelerated encephalization in early Homo. To better comprehend the real role of the MYH16 gene, we studied the primary proteins present in the muscle fibers of humans and non-humans, in order to understand if they really can be influenced by MYH16 gene. At this aim we examined the muscle-specific integrins, alpha 7B and beta 1D-integrins, and their relative fetal isoforms, alpha 7A and beta 1A-integrins, analyzing, by immunohistochemistry, muscle biopsies of two components of a chimpanzee's group in captivity, an alpha male and a non-alpha male subjects; all these integrins participate in vital biological processes such as maintenance of tissue integrity, embryonic development, cell

  7. Constant Fiber Number During Skeletal Muscle Atrophy and Modified Arachidonate Metabolism During Hypertrophy

    Science.gov (United States)

    Templeton, G.

    1985-01-01

    A previously documented shift from Type I to IIA predominance of the soleus muscle during rat suspension was further investigated to determine if this shift was by selective reduction of a single fiber type, simultaneous reduction and formation of fibers with different fiber types, or a transformation of fiber type by individual fibers. By partial acid digestion and dissection, average total soleus fiber number was found to be 3022 + or - 80 (SE) and 3008 + or - 64 before and after four-week suspension (n=12). Another area of current research was based on previous studies which indicate that prostaglandins are biosynthesized by skeletal muscle and evoke protein synthesis and degradation.

  8. Skeletal muscle fiber, nerve, and blood vessel breakdown in space-flown rats

    Science.gov (United States)

    Riley, D. A.; Ilyina-Kakueva, E. I.; Ellis, S.; Bain, J. L.; Slocum, G. R.; Sedlak, F. R.

    1990-01-01

    Histochemical and ultrastructural analyses were performed postflight on hind limb skeletal muscles of rats orbited for 12.5 days aboard the unmanned Cosmos 1887 biosatellite and returned to Earth 2 days before sacrifice. The antigravity adductor longus (AL), soleus, and plantaris muscles atrophied more than the non-weight-bearing extensor digitorum longus, and slow muscle fibers were more atrophic than fast fibers. Muscle fiber segmental necrosis occurred selectively in the AL and soleus muscles; primarily, macrophages and neutrophils infiltrated and phagocytosed cellular debris. Granule-rich mast cells were diminished in flight AL muscles compared with controls, indicating the mast cell secretion contributed to interstitial tissue edema. Increased ubiquitination of disrupted myofibrils implicated ubiquitin in myofilament degradation. Mitochondrial content and succinic dehydrogenase activity were normal, except for subsarcolemmal decreases. Myofibrillar ATPase activity of flight AL muscle fibers shifted toward the fast type. Absence of capillaries and extravasation of red blood cells indicated failed microcirculation. Muscle fiber regeneration from activated satellite cells was detected. About 17% of the flight AL end plates exhibited total or partial denervation. Thus, skeletal muscle weakness associated with spaceflight can result from muscle fiber atrophy and segmental necrosis, partial motor denervation, and disruption of the microcirculation.

  9. Muscle fiber conduction velocity in the diagnosis of sporadic hypokalemic periodic paralysis.

    Science.gov (United States)

    Brouwer, O F; Zwarts, M J; Links, T P; Wintzen, A R

    1992-01-01

    A 6-year-old girl presented with episodes of profound muscle weakness since the age of 2 years. On the basis of decreased ictal serum potassium level and lack of metabolic disorder, primary hypokalemic periodic paralysis (HPP) was diagnosed. Both parents and 3 sibs were unaffected clinically. In all of them asymptomatic heterozygosity was very unlikely by the finding of normal muscle fiber conduction velocities, whereas in the patient interictal muscle fiber conduction velocity was lowered. Determination of muscle fiber conduction velocity can be helpful in documenting sporadic occurrence of HPP. PMID:1324813

  10. Evidence for ACTN3 as a Speed Gene in Isolated Human Muscle Fibers

    OpenAIRE

    Broos, Siacia; Malisoux, Laurent; Theisen, Daniel; van Thienen, Ruud; Ramaekers, Monique; Jamart, Cécile; Deldicque, Louise; Thomis, Martine; Francaux, Marc

    2016-01-01

    Purpose To examine the effect of α-actinin-3 deficiency due to homozygosity for the ACTN3 577X-allele on contractile and morphological properties of fast muscle fibers in non-athletic young men. Methods A biopsy was taken from the vastus lateralis of 4 RR and 4 XX individuals to test for differences in morphologic and contractile properties of single muscle fibers. The cross-sectional area of the fiber and muscle fiber composition was determined using standard immunohistochemistry analyses. S...

  11. Influence of exercise contraction mode and protein supplementation on human skeletal muscle satellite cell content and muscle fiber growth

    DEFF Research Database (Denmark)

    Farup, Jean; Rahbek, Stine Klejs; Riis, Simon;

    2014-01-01

    Skeletal muscle satellite cells (SCs) are involved in remodeling and hypertrophy processes of skeletal muscle. However, little knowledge exists on extrinsic factors that influence the content of SCs in skeletal muscle. In a comparative human study, we investigated the muscle fiber type...... CSA increased exclusively with Whey-Conc (P < 0.01) and type II fiber hypertrophy correlated with whole muscle hypertrophy exclusively following Conc training (P < 0.01). In conclusion, isolated concentric knee extensor resistance training appears to constitute a stronger driver of SC content than......-specific association between emergence of satellite cells (SCs), muscle growth, and remodeling in response to 12 wk unilateral resistance training performed as eccentric (Ecc) or concentric (Conc) resistance training ± whey protein (Whey, 19.5 g protein + 19.5 g glucose) or placebo (Placebo, 39 g glucose...

  12. Effects of aging on muscle mechanical function and muscle fiber morphology during short-term immobilization and subsequent retraining

    DEFF Research Database (Denmark)

    Hvid, Lars; Aagaard, Per; Justesen, Lene;

    2010-01-01

    Very little attention has been given to the combined effects of aging and disuse as separate factors causing deterioration in muscle mechanical function. Thus the purpose of this study was to investigate the effects of 2 wk of immobilization followed by 4 wk of retraining on knee extensor muscle...... mechanical function (e.g., maximal strength and rapid force capacity) and muscle fiber morphology in 9 old (OM: 67.3 ± 1.3 yr) and 11 young healthy men (YM: 24.4 ± 0.5 yr) with comparable levels of physical activity. Following immobilization, OM demonstrated markedly larger decreases in rapid force capacity...... deleterious effects of short-term muscle disuse on muscle fiber size and rapid force capacity than YM. Furthermore, OM seems to require longer time to recover and regain rapid muscle force capacity, which may lead to a larger risk of falling in aged individuals after periods of short-term disuse....

  13. Contractile properties of rat, rhesus monkey, and human type I muscle fibers

    Science.gov (United States)

    Widrick, J. J.; Romatowski, J. G.; Karhanek, M.; Fitts, R. H.

    1997-01-01

    It is well known that skeletal muscle intrinsic maximal shortening velocity is inversely related to species body mass. However, there is uncertainty regarding the relationship between the contractile properties of muscle fibers obtained from commonly studied laboratory animals and those obtained from humans. In this study we determined the contractile properties of single chemically skinned fibers prepared from rat, rhesus monkey, and human soleus and gastrocnemius muscle samples under identical experimental conditions. All fibers used for analysis expressed type I myosin heavy chain as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Allometric coefficients for type I fibers from each muscle indicated that there was little change in peak tension (force/fiber cross-sectional area) across species. In contrast, both soleus and gastrocnemius type I fiber maximal unloaded shortening velocity (Vo), the y-intercept of the force-velocity relationship (Vmax), peak power per unit fiber length, and peak power normalized for fiber length and cross-sectional area were all inversely related to species body mass. The present allometric coefficients for soleus fiber Vo (-0.18) and Vmax (-0.11) are in good agreement with published values for soleus fibers obtained from common laboratory and domesticated mammals. Taken together, these observations suggest that the Vo of slow fibers from quadrupeds and humans scale similarly and can be described by the same quantitative relationships. These findings have implications in the design and interpretation of experiments, especially those that use small laboratory mammals as a model of human muscle function.

  14. Effects of pH on contraction of rabbit fast and slow skeletal muscle fibers.

    OpenAIRE

    Chase, P B; Kushmerick, M J

    1988-01-01

    We have investigated (a) effects of varying proton concentration on force and shortening velocity of glycerinated muscle fibers, (b) differences between these effects on fibers from psoas (fast) and soleus (slow) muscles, possibly due to differences in the actomyosin ATPase kinetic cycles, and (c) whether changes in intracellular pH explain altered contractility typically associated with prolonged excitation of fast, glycolytic muscle. The pH range was chosen to cover the physiological pH ran...

  15. Flash and smash: rapid freezing of muscle fibers activated by photolysis of caged ATP.

    OpenAIRE

    Hirose, K.; Lenart, T D; Murray, J.M.; Franzini-Armstrong, C; Goldman, Y E

    1993-01-01

    A new approach was used to study transient structural states of cross-bridges during activation of muscle fibers. Rabbit skinned muscle fibers were rapidly and synchronously activated from the rigor state by photolysis of caged ATP in the presence of Ca2+. At several different times during the switch from rigor to fully active tension development, the fibers were rapidly frozen on a liquid helium-cooled metal block, freeze-substituted, and examined in an electron microscope. The limits of str...

  16. A Novel Method to Measure Glucose Uptake and Myosin Heavy Chain Isoform Expression of Single Fibers From Rat Skeletal Muscle

    OpenAIRE

    MacKrell, James G.; Gregory D. Cartee

    2012-01-01

    Skeletal muscle includes many individual fibers with diverse phenotypes. A barrier to understanding muscle glucose uptake at the cellular level has been the absence of a method to measure glucose uptake by single fibers from mammalian skeletal muscle. This study’s primary objective was to develop a procedure to measure glucose uptake by single fibers from rat skeletal muscle. Rat epitrochlearis muscles were incubated ex vivo with [3H]-2-deoxy-d-glucose, with or without insulin or AICAR, befor...

  17. Persistent muscle fiber regeneration in long term denervation. Past, present, future

    Directory of Open Access Journals (Sweden)

    Ugo Carraro

    2015-03-01

    Full Text Available Despite the ravages of long term denervation there is structural and ultrastructural evidence for survival of muscle fibers in mammals, with some fibers surviving at least ten months in rodents and 3-6 years in humans. Further, in rodents there is evidence that muscle fibers may regenerate even after repeated damage in the absence of the nerve, and that this potential is maintained for several months after denervation. While in animal models permanently denervated muscle sooner or later loses the ability to contract, the muscles may maintain their size and ability to function if electrically stimulated soon after denervation. Whether in mammals, humans included, this is a result of persistent de novo formation of muscle fibers is an open issue we would like to explore in this review. During the past decade, we have studied muscle biopsies from the quadriceps muscle of Spinal Cord Injury (SCI patients suffering with Conus and Cauda Equina syndrome, a condition that fully and irreversibly disconnects skeletal muscle fibers from their damaged innervating motor neurons. We have demonstrated that human denervated muscle fibers survive years of denervation and can be rescued from severe atrophy by home-based Functional Electrical Stimulation (h-bFES. Using immunohistochemistry with both non-stimulated and the h-bFES stimulated human muscle biopsies, we have observed the persistent presence of muscle fibers which are positive to labeling by an antibody which specifically recognizes the embryonic myosin heavy chain (MHCemb. Relative to the total number of fibers present, only a small percentage of these MHCemb positive fibers are detected, suggesting that they are regenerating muscle fibers and not pre-existing myofibers re-expressing embryonic isoforms. Although embryonic isoforms of acetylcholine receptors are known to be re-expressed and to spread from the end-plate to the sarcolemma of muscle fibers in early phases of muscle denervation, we suggest

  18. Changes in skeletal muscle biochemistry and histology relative to fiber type in rats with heart failure

    Science.gov (United States)

    Delp, M. D.; Duan, C.; Mattson, J. P.; Musch, T. I.

    1997-01-01

    One of the primary consequences of left ventricular dysfunction (LVD) after myocardial infarction is a decrement in exercise capacity. Several factors have been hypothesized to account for this decrement, including alterations in skeletal muscle metabolism and aerobic capacity. The purpose of this study was to determine whether LVD-induced alterations in skeletal muscle enzyme activities, fiber composition, and fiber size are 1) generalized in muscles or specific to muscles composed primarily of a given fiber type and 2) related to the severity of the LVD. Female Wistar rats were divided into three groups: sham-operated controls (n = 13) and rats with moderate (n = 10) and severe (n = 7) LVD. LVD was surgically induced by ligating the left main coronary artery and resulted in elevations (P < 0.05) in left ventricular end-diastolic pressure (sham, 5 +/- 1 mmHg; moderate LVD, 11 +/- 1 mmHg; severe LVD, 25 +/- 1 mmHg). Moderate LVD decreased the activities of phosphofructokinase (PFK) and citrate synthase in one muscle composed of type IIB fibers but did not modify fiber composition or size of any muscle studied. However, severe LVD diminished the activity of enzymes involved in terminal and beta-oxidation in muscles composed primarily of type I fibers, type IIA fibers, and type IIB fibers. In addition, severe LVD induced a reduction in the activity of PFK in type IIB muscle, a 10% reduction in the percentage of type IID/X fibers, and a corresponding increase in the portion of type IIB fibers. Atrophy of type I fibers, type IIA fibers, and/or type IIB fibers occurred in soleus and plantaris muscles of rats with severe LVD. These data indicate that rats with severe LVD after myocardial infarction exhibit 1) decrements in mitochondrial enzyme activities independent of muscle fiber composition, 2) a reduction in PFK activity in type IIB muscle, 3) transformation of type IID/X to type IIB fibers, and 4) atrophy of type I, IIA, and IIB fibers.

  19. Function of longitudinal vs circular muscle fibers in esophageal peristalsis, deduced with mathematical modeling

    Institute of Scientific and Technical Information of China (English)

    James G Brasseur; Mark A Nicosia; Anupam Pal; Larr S Miller

    2007-01-01

    We summarize from previous works the functions of circular vs. longitudinal muscle in esophageal peristaltic bolus transport using a mix of experimental data, the conservation laws of mechanics and mathematical modeling. Whereas circular muscle tone generates radial closure pressure to create a local peristaltic closure wave, longitudinal muscle tone has two functions, one physiological with mechanical implications, and one purely mechanical. Each of these functions independently reduces the tension of individual circular muscle fibers to maintain closure as a consequence of shortening of longitudinal muscle locally coordinated with increasing circular muscle tone. The physiological function is deduced by combining basic laws of mechanics with concurrent measurements of intraluminal pressure from manometry, and changes in cross sectional muscle area from endoluminal ultrasound from which local longitudinal shortening (LLS) can be accurately obtained. The purely mechanical function of LLS was discovered from mathematical modeling of peristaltic esophageal transport with the axial wall motion generated by LLS. Physiologically, LLS concentrates circular muscle fibers where closure pressure is highest.However, the mechanical function of LLS is to reduce the level of pressure required to maintain closure. The combined physiological and mechanical consequences of LLS are to reduce circular muscle fiber tension and power by as much as 1/10 what would be required for peristalsis without the longitudinal muscle layer, a tremendous benefit that may explain the existence of longitudinal muscle fiber in the gut. We also review what is understood of the role of longitudinal muscle in esophageal emptying, reflux and pathology.

  20. Contractile properties of single permeabilized muscle fibers from congenital cleft palates and normal palates of Spanish goats

    Science.gov (United States)

    A goat model in which cleft palate is induced by the plant alkaloid, anabasine was used to determine muscle fiber integrity of the levator veli palatine muscle. It was determined that the muscle fibers of the cleft palate-induced goats were primarily of the type 2 (fast fibers) which fatigue easil...

  1. Human muscle fiber type-specific insulin signaling: Impact of obesity and type 2 diabetes

    DEFF Research Database (Denmark)

    Albers, Peter Hjorth; Pedersen, Andreas J T; Birk, Jesper Bratz; Kristensen, Dorte Enggaard; Vind, Birgitte F; Baba, Otto; Nøhr, Jane; Højlund, Kurt; Wojtaszewski, Jørgen

    2015-01-01

    /or metabolic enzymes. Pools of type I and II fibers were prepared from biopsies of the vastus lateralis muscles from lean, obese and type 2 diabetic subjects before and after a hyperinsulinemic-euglycemic clamp. Type I fibers compared to type II fibers have higher protein levels of the insulin receptor, GLUT4...... insulin adjusted for protein level were not different between fiber types. Independently of fiber type, insulin signaling was similar (TBC1D1, GS and PDH-E1α) or decreased (Akt and TBC1D4) in muscle from patients with type 2 diabetes compared to lean and obese subjects. We conclude that human type I...

  2. Ontogenetic changes in skeletal muscle fiber type, fiber diameter and myoglobin concentration in the Northern elephant seal (Mirounga angustirostris

    Directory of Open Access Journals (Sweden)

    Colby eMoore

    2014-06-01

    Full Text Available Northern elephant seals (Mirounga angustirostris (NES are known to be deep, long-duration divers and to sustain long-repeated patterns of breath-hold, or apnea. Some phocid dives remain within the bounds of aerobic metabolism, accompanied by physiological responses inducing lung compression, bradycardia and peripheral vasoconstriction. Current data suggest an absence of type IIb fibers in pinniped locomotory musculature. To date, no fiber type data exist for NES, a consummate deep diver. In this study, NES were biopsied in the wild. Ontogenetic changes in skeletal muscle were revealed through succinate dehydrogenase (SDH based fiber typing. Results indicated a predominance of uniformly shaped, large type I fibers and elevated myoglobin (Mb concentrations in the longissimus dorsi (LD muscle of adults. No type II muscle fibers were detected in any adult sampled. This was in contrast to the juvenile animals that demonstrated type II myosin in Western Blot analysis, indicative of an ontogenetic change in skeletal muscle with maturation. These data support previous hypotheses that the absence of type II fibers indicates reliance on aerobic metabolism during dives, as well as a depressed metabolic rate and low energy locomotion. We also suggest that the lack of type IIb fibers (adults may provide a protection against ischemia reperfusion (IR injury in vasoconstricted peripheral skeletal muscle.

  3. Blood vessels and desmin control the positioning of nuclei in skeletal muscle fibers

    DEFF Research Database (Denmark)

    Ralston, E; Lu, Z; Biscocho, N;

    2006-01-01

    Skeletal muscle fibers contain hundreds to thousands of nuclei which lie immediately under the plasmalemma and are spaced out along the fiber, except for a small cluster of specialized nuclei at the neuromuscular junction. How the nuclei attain their positions along the fiber is not understood...

  4. A Contractile Network of Interstitial Cells of Cajal in the Supratarsal Mueller's Smooth Muscle Fibers With Sparse Sympathetic Innervation

    OpenAIRE

    Yuzuriha, Shunsuke; Matsuo, Kiyoshi; Ban, Ryokuya; Yano, Shiharu; Moriizumi, Tetsuji

    2012-01-01

    Background: We previously reported that the supratarsal Mueller's muscle is innervated by both sympathetic efferent fibers and trigeminal proprioceptive afferent fibers, which function as mechanoreceptors-inducing reflexive contractions of both the levator and frontalis muscles. Controversy still persists regarding the role of the mechanoreceptors in Mueller's muscle; therefore, we clinically and histologically investigated Mueller's muscle. Methods: We evaluated the role of phenylephrine adm...

  5. Effect of passive stretching on the immobilized soleus muscle fiber morphology

    Directory of Open Access Journals (Sweden)

    Coutinho E.L.

    2004-01-01

    Full Text Available The aim of the present study was to determine the effect of stretching applied every 3 days to the soleus muscle immobilized in the shortened position on muscle fiber morphology. Eighteen 16-week-old Wistar rats were used and divided into three groups of 6 animals each: a the left soleus muscle was immobilized in the shortened position for 3 weeks; b during immobilization, the soleus was stretched for 40 min every 3 days; c the non-immobilized soleus was only stretched. Left and right soleus muscles were examined. One portion of the soleus was frozen for histology and muscle fiber area evaluation, while the other portion was used to identify the number and length of serial sarcomeres. Immobilized muscles (group A showed a significant decrease in weight (44 ± 6%, length (19 ± 7%, serial sarcomere number (23 ± 15%, and fiber area (37 ± 31% compared to the contralateral muscles (P < 0.05, paired Student t-test. The immobilized and stretched soleus (group B showed a similar reduction but milder muscle fiber atrophy compared to the only immobilized group (22 ± 40 vs 37 ± 31%, respectively; P < 0.001, ANOVA test. Muscles submitted only to stretching (group C significantly increased the length (5 ± 2%, serial sarcomere number (4 ± 4%, and fiber area (16 ± 44% compared to the contralateral muscles (P < 0.05, paired Student t-test. In conclusion, stretching applied every 3 days to immobilized muscles did not prevent the muscle shortening, but reduced muscle atrophy. Stretching sessions induced hypertrophic effects in the control muscles. These results support the use of muscle stretching in sports and rehabilitation.

  6. The effect of resistance training combined with timed ingestion of protein on muscle fiber size and muscle strength

    DEFF Research Database (Denmark)

    Andersen, Lars L; Tufekovic, Goran; Zebis, Mette K;

    2005-01-01

    of resistance training combined with timed ingestion of isoenergetic protein vs carbohydrate supplementation on muscle fiber hypertrophy and mechanical muscle performance. Supplementation was administered before and immediately after each training bout and, in addition, in the morning on nontraining......) concentric and eccentric contractions of the knee extensor muscle was measured in an isokinetic dynamometer. After 14 weeks of resistance training, the protein group showed hypertrophy of type I (18% +/- 5%; P < .01) and type II (26% +/- 5%; P < .01) muscle fibers, whereas no change above baseline occurred......Acute muscle protein metabolism is modulated not only by resistance exercise but also by amino acids. However, less is known about the long-term hypertrophic effect of protein supplementation in combination with resistance training. The present study was designed to compare the effect of 14 weeks...

  7. Morphometric analysis of rat muscle fibers following space flight and hypogravity

    Science.gov (United States)

    Chui, L. A.; Castleman, K. R.

    1982-01-01

    The effect of hypogravity on striate muscles, containing both fast twitch glycolytic and slow twitch oxidative fibers, was studied in rats aboard two Cosmos biosatellites. Results of a computer-assisted image analysis of extensor digitorum muscles from five rats, exposed to 18.5 days of hypogravity and processed for the alkaline ATPase reaction, showed a reduction of the mean fiber diameter (41.32 + or - 0.55 microns), compared to synchronous (46.32 + or - 0.55 microns) and vivarium (49 + or - 0.5 microns) controls. A further experiment studied the ratio of fast to slow twitch fibers in 25 rats exposed to 18.5 days of hypogravity and analyzed at four different periods of recovery following the space flight. Using the previous techniques, the gastrocnemius muscle showed a reduction of the total muscle fiber area in square microns and a reduction in the percentage of slow fibers of flight animals compared to the control animals.

  8. Catalase-positive microperoxisomes in rat soleus and extensor digitorum longus muscle fiber types

    Science.gov (United States)

    Riley, Danny A.; Bain, James L. W.; Ellis, Stanley

    1988-01-01

    The size, distribution, and content of catalase-reactive microperoxisomes were investigated cytochemically in three types of muscle fibers from the soleus and the extensor digitorum longus (EDL) of male rats. Muscle fibers were classified on the basis of the mitochondrial content and distribution, the Z-band widths, and the size and shape of myofibrils as the slow-twitch oxidative (SO), the fast-twitch oxidative glycolytic (FOG), and the fast-twitch glycolytic (FG) fibers. It was found that both the EDL and soleus SO fibers possessed the largest microperoxisomes. A comparison of microperoxisome number per muscle fiber area or the microperoxisome area per fiber area revealed following ranking, starting from the largest number and the area-ratio values: soleus SO, EDL SO, EDL FOG, and EDL FG.

  9. Slow to fast alterations in skeletal muscle fibers caused by clenbuterol, a beta(2)-receptor agonist

    Science.gov (United States)

    Zeman, Richard J.; Ludemann, Robert; Easton, Thomas G.; Etlinger, Joseph D.

    1988-01-01

    The effects of a beta(2)-receptor agonist, clenbuterol, and a beta(2) antagonist, butoxamine, on the skeletal muscle fibers of rats were investigated. It was found that chronic treatment of rats with clenbuterol caused hypertrophy of histochemically identified fast-twitch, but not slow-twitch, fibers within the soleus, while in the extensor digitorum longus the mean areas of both fiber types were increased; in both muscles, the ratio of the number of fast-twitch to slow-twitch fibers was increased. In contrast, a treatment with butoxamine caused a reduction of the fast-twitch fiber size in both muscles, and the ratio of the fast-twitch to slow-twitch fibers was decreased.

  10. MuRF1 is a muscle fiber type II associated factor and together with MuRF2 regulates type II fiber trophicity and maintenance

    OpenAIRE

    Moriscot, Anselmo; Baptista, Igor L.; Bogomolovas, Julius; Krohne, Christian; Hirner, Stephanie; Granzier, Henk; Labeit, Siegfried

    2010-01-01

    MuRF1 is a member of the RBCC (RING, B-box, coiled-coil) superfamily that has been proposed to act as an atrogin during muscle wasting. Here, we show that MuRF1 is preferentially expressed in type II muscle fibers. Five and 14 days after denervation, MuRF1 protein was further elevated but remained preferentially expressed in type-II muscle fibers. Consistent with a fiber-type dependent function of MuRF1, the tibialis anterior muscle (rich in type-II muscle fibers) was considerably more protec...

  11. Distribution of tropomyosin isoforms in different types of single fibers isolated from bovine skeletal muscles.

    Science.gov (United States)

    Oe, M; Ojima, K; Nakajima, I; Chikuni, K; Shibata, M; Muroya, S

    2016-08-01

    To clarify the relationship between myosin heavy chain (MyHC) isoforms and tropomyosin (TPM) isoforms in single fibers, 64 single fibers were isolated from each of bovine three muscles (masseter, semispinalis and semitendinosus). mRNA expressions of MyHC and TPM isoforms were analyzed by real-time PCR. All single fibers from the masseter expressed MyHC-slow. The fibers from the semispinalis expressed both MyHC-slow and 2a. The fibers from the semitendinosus expressed MyHC-slow, 2a and 2x. TPM-1 and TPM-2 were co-expressed in 2a and 2x type fibers, and TPM-2 and TPM-3 were co-expressed in slow type fibers. The expression pattern of TPM isoforms in each fiber type was similar between fibers isolated from different muscles. These results suggest that TPM-1 and TPM-3 isoforms correspond to the function of 2a or 2x type fibers and slow type fibers, respectively, with TPM-2 in common. Furthermore, the patterns of MyHC and TPM isoform combinations did not vary among single fibers isolated from the individual muscles examined. PMID:27105153

  12. Metabolic and morphologic properties of single muscle fibers in the rat after spaceflight, Cosmos 1887

    Science.gov (United States)

    Miu, B.; Martin, T. P.; Roy, R. R.; Oganov, V.; Ilyina-Kakueva, E.; Marini, J. F.; Leger, J. J.; Bodine-Fowler, S. C.; Edgerton, V. R.

    1990-01-01

    The adaptation of a slow (soleus, Sol) and a fast (medial gastrocnemius, MG) skeletal muscle to spaceflight was studied in five young male rats. The flight period was 12.5 days and the rats were killed approximately 48 h after returning to 1 g. Five other rats that were housed in cages similar to those used by the flight rats were maintained at 1 g for the same period of time to serve as ground-based controls. Fibers were classified as dark or light staining for myosin adenosine triphosphatase (ATPase). On the average, the fibers in the Sol of the flight rats atrophied twice as much as those in the MG. Further, the fibers located in the deep (close to the bone and having the highest percentage of light ATPase and high oxidative fibers in the muscle cross section) region of the MG atrophied more than the fibers located in the superficial (away from the bone and having the lowest percentage of light ATPase and high oxidative fibers in the muscle cross-section) region of the muscle. Based on quantitative histochemical assays of single muscle fibers, succinate dehydrogenase (SDH) activity per unit volume was unchanged in fibers of the Sol and MG. However, in the Sol, but not the MG, the total amount of SDH activity in a 10-microns-thick section of a fiber decreased significantly in response to spaceflight. Based on population distributions, it appears that the alpha-glycerophosphate dehydrogenase (GPD) activities were elevated in the dark ATPase fibers in the Sol, whereas the light fibers in the Sol and both fiber types in the MG did not appear to change. The ratio of GPD to SDH activities increased in the dark (but not light) fibers of the Sol and was unaffected in the MG. Immunohistochemical analyses indicate that approximately 40% of the fibers in the Sol of flight rats expressed a fast myosin heavy chain compared with 22% in control rats. Further, 31% of the fibers in the Sol of flight rats expressed both fast and slow myosin heavy chains compared with 8% in

  13. Caveolin-3 is associated with the T-tubules of mature skeletal muscle fibers

    DEFF Research Database (Denmark)

    Ralston, E; Ploug, Thorkil

    1999-01-01

    Caveolae are abundant in skeletal muscle and their coat contains a specific isoform of caveolin, caveolin-3. It has been suggested that during muscle development, caveolin-3 is associated with the T-tubules, but that in adult muscle it is found on the plasma membrane only. We have studied...... the distribution of caveolin-3 in single skeletal muscle fibers from adult rat soleus by confocal immunofluorescence and by immunogold electron microscopy. We found that caveolin-3 occurs at the highest density on the plasma membrane but is also present in the core of the fibers, at the I-band/A-band interface...

  14. Gravitational unloading effects on muscle fiber size, phenotype and myonuclear number

    Science.gov (United States)

    Ohira, Y.; Yoshinaga, T.; Nomura, T.; Kawano, F.; Ishihara, A.; Nonaka, I.; Roy, R. R.; Edgerton, V. R.

    2002-01-01

    The effects of gravitational unloading with or without intact neural activity and/or tension development on myosin heavy chain (MHC) composition, cross-sectional area (CSA), number of myonuclei, and myonuclear domain (cytoplasmic volume per myonucleus ratio) in single fibers of both slow and fast muscles of rat hindlimbs are reviewed briefly. The atrophic response to unloading is generally graded as follows: slow extensors > fast extensors > fast flexors. Reduction of CSA is usually greater in the most predominant fiber type of that muscle. The percentage of fibers expressing fast MHC isoforms increases in unloaded slow but not fast muscles. Myonuclear number per mm of fiber length and myonuclear domain is decreased in the fibers of the unloaded predominantly slow soleus muscle, but not in the predominantly fast plantaris. Decreases in myonuclear number and domain, however, are observed in plantaris fibers when tenotomy, denervation, or both are combined with hindlimb unloading. All of these results are consistent with the view that a major factor for fiber atrophy is an inhibition or reduction of loading of the hindlimbs. These data also indicate that predominantly slow muscles are more responsive to unloading than predominantly fast muscles. c2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

  15. Electrophysiology and Dye-Coupling Are Sexually Dimorphic Characteristics of Individual Laryngeal Muscle Fibers in Xenopus laevis

    OpenAIRE

    Tobias, Martha L.; Kelley, Darcy B.

    1988-01-01

    Sex differences at the laryngeal neuromuscular junction of Xenopus laevis were examined by recording intracellularly from muscle fibers in response to nerve stimulation. Male laryngeal muscle contains 2 physiologically distinct fiber types. Type I fibers generate postsynaptic potentials in response to low-magnitude stimulus pulses and action potentials in response to higher-magnitude stimulus pulses. Type II muscle fibers require repetitive stimulation for action potential production, probabl...

  16. Experiment K-308: Automatic analysis of muscle fibers from rats subjected to spaceflight

    Science.gov (United States)

    Castleman, K. R.; Chui, L. A.; Vandermeullen, J. P.

    1981-01-01

    The morphology of histochemically prepared muscle sections from the gastrocnemius and plantaris muscles of flight and vivarium control rats was studied quantitatively. Both fast-twitch and slow-twitch fibers were significantly smaller in flight groups than in control groups. Fibers in group 4F were somewhat larger than in 1F, presumably due to growth after recovery. Fibers in 4V were slightly larger than in 1V, presumably due to age. The slow fibers showed more spaceflight induced size loss than fast fibers, suggesting they suffered more from hypogravity. The proportion of slow fibers was also lower in the flight groups, suggesting spaceflight induced fiber type conversion from slow to fast.

  17. 2-Deoxyglucose autoradiography of single motor units: labelling of individual acutely active muscle fibers

    International Nuclear Information System (INIS)

    2-Deoxy-D-[1-14C]glucose (2DG) was given intravenously during repetitive stimulation of single motor units in adult cats and autoradiographs were made of frozen sections of the target muscles in order to evaluate methods designed to improve the spatial resolution of [14C]2DG autoradiography. With the modifications used, acutely active muscle fibers, independently identified by depletion of intrafiber glycogen, were associated with highly localized accumulations of silver grains over the depleted fibers. The results indicate that [14C]2DG autoradiography can successfully identify individual active muscle fibers and might in principle be used to obtain quantitative data about rates of glucose metabolism in single muscle fibers of defined histochemical type. The modifications may be applicable also to other tissues to give improved spatial resolution with [14C]-labeled metabolic markers. (Auth.)

  18. Ultrastructural study of muscles fibers in tick Hyalomma (Hyalomma) anatolicum anatolicum (Ixodoidea: Ixodidae).

    Science.gov (United States)

    Bughdadi, Faisal A

    2010-09-01

    In the present study, ticks were obtained from a colony maintained at 28 degrees C and 75% relative humidity in at the Department of Biology, University College Umm Al-Qura University, Saudi Arabia and the Transmission Electron Microscope technique (TEM) was used to describes the ultrastructure and description of muscle of the of ixodid tick Hyalomma (Hyalomma) anatolicum anatolicum. The results showed that muscles of the unfed ticks Hyalomma (Hyalomma) anatolicum anatolicum in longitudinal sections are spindle-shaped to cylindrical muscle fibers. In the unfed nymph Hyalomma (Hyalomma) anatolicum anatolicum skeletal and visceral muscles are distinguished according to structure, function and position. These muscles include the capitulum, dorsoventral and leg oblique muscles. All muscle fibers are ensheathed (covered by sheath) in a sarcolemma. Their muscle fibers have striated pattern of successive sarcomeres whose thick myosin filaments are surrounded by orbitals of up to 12 thin actin filaments. The cytoplasm of the epidermal cell appears largely devoted with complicated microtubules present in parallel with long axis of adjacent muscle fibers. The cell membrane invaginates into tubular system extending deeply into the sarcoplasm and closely associated to cisternae of sarcoplasmic reticulum. The tubular system and sarcoplasmic reticulum forming two-membered (dyads) are considered to be the main route of calcium ions whose movement are synchronized with the motor impulse to control muscles contraction. In the sarcoplasm two types of muscle fibers are recognized according to thickness and density and mitochondrial size, distribution and population. Both skeletal and visceral muscles are invaginated by tracheoles and innervated by nerve axons containing synaptic vesicles. The actin and myosin filaments are slightly interrupted and the tubular system sarcoplasmic reticulum is well demonstrated. PMID:21313907

  19. Contraction and AICAR Stimulate IL-6 Vesicle Depletion From Skeletal Muscle Fibers In Vivo

    DEFF Research Database (Denmark)

    Lauritzen, Hans P M M; Brandauer, Josef; Schjerling, Peter;

    2013-01-01

    Recent studies suggest that interleukin 6 (IL-6) is released from contracting skeletal muscles; however, the cellular origin, secretion kinetics, and signaling mechanisms regulating IL-6 secretion are unknown. To address these questions, we developed imaging methodology to study IL-6 in fixed mouse...... muscle fibers and in live animals in vivo. Using confocal imaging to visualize endogenous IL-6 protein in fixed muscle fibers, we found IL-6 in small vesicle structures distributed throughout the fibers under basal (resting) conditions. To determine the kinetics of IL-6 secretion, intact quadriceps...... muscles were transfected with enhanced green fluorescent protein (EGFP)-tagged IL-6 (IL-6-EGFP), and 5 days later anesthetized mice were imaged before and after muscle contractions in situ. Contractions decreased IL-6-EGFP-containing vesicles and protein by 62% (P <0.05), occurring rapidly and...

  20. Effects of chronic centrifugation on skeletal muscle fibers in young developing rats

    Science.gov (United States)

    Martin, W. D.

    1980-01-01

    Three groups of 30-d old male and female rats were centrifuged for 2, 4, 8, and 16 weeks, after which their soleus and plantaris muscles were analysed for changes in proportions of muscle fiber types. The groups were: earth control, maintained at earth gravity without rotation; rotation control, subjected to a gravitational force of 1.05 G and 28 rpm; and rotation experimental, subjected to a gravitational force of 2 G and 28 rpm. Muscle fibers were classified into four fiber types on the basis of actomyosin ATPase activity as slow oxidative, fast oxidative glycolytic and either fast glycolytic (plantaris) or intermediate (soleus). Hypergravity resulted in an increase in slow oxidative fibers in soleus relative to the earth control, but not of females treated similarly. The relationship of body weight to the changes in proportion of slow oxidative fibers is discussed.

  1. Trigeminal Proprioception Evoked by Strong Stretching of the Mechanoreceptors in Müller's Muscle Induces Reflex Contraction of the Orbital Orbicularis Oculi Slow-Twitch Muscle Fibers

    OpenAIRE

    Matsuo, Kiyoshi; Ban, Ryokuya; Ban, Midori; Yuzuriha, Shunsuke

    2014-01-01

    Objective: The mixed orbicularis oculi muscle lacks an intramuscular proprioceptive system such as muscle spindles, to induce reflex contraction of its slow-twitch fibers. We evaluated whether the mechanoreceptors in Müller's muscle function as extrinsic mechanoreceptors to induce reflex contraction of the slow-twitch fibers of the orbicularis oculi in addition to those of the levator and frontalis muscles. Methods: We evaluated in patients with aponeurosis-disinserted blepharoptosis whether ...

  2. Systems Biology of Skeletal Muscle: Fiber Type as an Organizing Principle

    OpenAIRE

    Greising, Sarah M.; Heather M Gransee; Mantilla, Carlos B.; Sieck, Gary C.

    2012-01-01

    Skeletal muscle force generation and contraction are fundamental to countless aspects of human life. The complexity of skeletal muscle physiology is simplified by fiber type classification where differences are observed from neuromuscular transmission to release of intracellular Ca2+ from the sarcoplasmic reticulum and the resulting recruitment and cycling of cross-bridges. This review uses fiber type classification as an organizing and simplifying principle to explore the complex interaction...

  3. Intracellular MMP-2 Activity in Skeletal Muscle is Associated with Type II Fibers

    OpenAIRE

    Hadler-Olsen, Elin Synnøve; Solli, Ann Iren; Hafstad, Anne Dragøy; Winberg, Jan-Olof; Uhlin-Hansen, Lars

    2014-01-01

    Matrix metalloproteinase 2 (MMP-2) is a proteolytic enzyme implicated in motility, differentiation, and regeneration of skeletal muscle fibers through processing of extracellular substrates. Although MMP-2 has been found to be localized intracellularly in cardiomyocytes where the enzyme is thought to contribute to post-ischemic loss of contractility, little is known about intracellular MMP-2 activity in skeletal muscle fibers. In the present study we demonstrate intracellular MMP-2 in normal ...

  4. A new method for non-invasive estimation of human muscle fiber type composition.

    Directory of Open Access Journals (Sweden)

    Audrey Baguet

    Full Text Available BACKGROUND: It has been established that excellence in sports with short and long exercise duration requires a high proportion of fast-twitch (FT or type-II fibers and slow-twitch (ST or type-I fibers, respectively. Until today, the muscle biopsy method is still accepted as gold standard to measure muscle fiber type composition. Because of its invasive nature and high sampling variance, it would be useful to develop a non-invasive alternative. METHODOLOGY: Eighty-three control subjects, 15 talented young track-and-field athletes, 51 elite athletes and 14 ex-athletes volunteered to participate in the current study. The carnosine content of all 163 subjects was measured in the gastrocnemius muscle by proton magnetic resonance spectroscopy ((1H-MRS. Muscle biopsies for fiber typing were taken from 12 untrained males. PRINCIPAL FINDINGS: A significant positive correlation was found between muscle carnosine, measured by (1H-MRS, and percentage area occupied by type II fibers. Explosive athletes had ∼30% higher carnosine levels compared to a reference population, whereas it was ∼20% lower than normal in typical endurance athletes. Similar results were found in young talents and ex-athletes. When active elite runners were ranked according to their best running distance, a negative sigmoidal curve was found between logarithm of running distance and muscle carnosine. CONCLUSIONS: Muscle carnosine content shows a good reflection of the disciplines of elite track-and-field athletes and is able to distinguish between individual track running distances. The differences between endurance and sprint muscle types is also observed in young talents and former athletes, suggesting this characteristic is genetically determined and can be applied in early talent identification. This quick method provides a valid alternative for the muscle biopsy method. In addition, this technique may also contribute to the diagnosis and monitoring of many conditions and

  5. Intrauterine growth-restricted sheep fetuses exhibit smaller hindlimb muscle fibers and lower proportions of insulin-sensitive Type I fibers near term.

    Science.gov (United States)

    Yates, Dustin T; Cadaret, Caitlin N; Beede, Kristin A; Riley, Hannah E; Macko, Antoni R; Anderson, Miranda J; Camacho, Leticia E; Limesand, Sean W

    2016-06-01

    Intrauterine growth restriction (IUGR) reduces muscle mass and insulin sensitivity in offspring. Insulin sensitivity varies among muscle fiber types, with Type I fibers being most sensitive. Differences in fiber-type ratios are associated with insulin resistance in adults, and thus we hypothesized that near-term IUGR sheep fetuses exhibit reduced size and proportions of Type I fibers. Placental insufficiency-induced IUGR fetuses were ∼54% smaller (P muscles contained less (P fibers than controls, but MyHC-II protein concentrations, Type II fibers, and Type IIx fibers were not different. IUGR biceps femoris muscles exhibited similar albeit less dramatic differences in fiber type proportions. Type I and IIa fibers are more responsive to adrenergic and insulin regulation than Type IIx and may be more profoundly impaired by the high catecholamines and low insulin in our IUGR fetuses, leading to their proportional reduction. In both muscles, fibers of each type were uniformly smaller (P fiber hypertrophy is not dependent on type but rather on other factors such as myoblast differentiation or protein synthesis. Together, our findings show that IUGR fetal muscles develop smaller fibers and have proportionally fewer Type I fibers, which is indicative of developmental adaptations that may help explain the link between IUGR and adulthood insulin resistance. PMID:27053651

  6. Contraction-induced injury to single permeabilized muscle fibers from normal and congenitally-clefted goat palates

    Science.gov (United States)

    A goat model in which cleft palate is induced by the plant alkaloid, anabasine was used to determine muscle fiber integrity of the levator veli palatine (LVP) muscle. It was determined that muscle fiber type, size, and sensitivity to contraction-induced injury was different between cleft palate ind...

  7. Effects of tetracaine on charge movements and calcium signals in frog skeletal muscle fibers

    OpenAIRE

    Vergara, Julio; Caputo, Carlo

    1983-01-01

    Intramembrane charge movements in skeletal muscle fibers contain a tetracaine-sensitive component that can be isolated by the use of this drug. The time course and voltage dependence of this component, studied in relation to antipyrylazo III absorbance signals, suggest its direct involvement in the calcium release process in muscle.

  8. The organization of the Golgi complex and microtubules in skeletal muscle is fiber type-dependent

    DEFF Research Database (Denmark)

    Ralston, E; Lu, Z; Ploug, Thorkil

    1999-01-01

    Skeletal muscle has a nonconventional Golgi complex (GC), the organization of which has been a subject of controversy in the past. We have now examined the distribution of the GC by immunofluorescence and immunogold electron microscopy in whole fibers from different rat muscles, both innervated...

  9. Suppression of contractile force in muscle fibers by antibody to myosin subfragment 2.

    OpenAIRE

    Lovell, S; Karr, T; Harrington, W F

    1988-01-01

    Polyclonal antibody directed against the subfragment-2 region of myosin was purified by affinity chromatography. Skinned muscle fibers that had been preincubated with antibody were able to sustain only 7% of the active isometric force generated by control fibers. The effect of antibody on force production could not be accounted for by inhibition of ATP turnover.

  10. Redundancy or heterogeneity in the electric activity of the biceps brachii muscle? Added value of PCA-processed multi-channel EMG muscle activation estimates in a parallel-fibered muscle

    OpenAIRE

    Staudenmann, Didier; Stegeman, Dick F.; van Dieën, Jaap H.

    2013-01-01

    Conventional bipolar EMG provides imprecise muscle activation estimates due to possibly heterogeneous activity within muscles and due to improper alignment of the electrodes with the muscle fibers. Principal component analysis (PCA), applied on multi-channel monopolar EMG yielded substantial improvements in muscle activation estimates in pennate muscles. We investigated the degree of heterogeneity in muscle activity and the contribution of PCA to muscle activation estimates in biceps brachii ...

  11. Confocal laser microscopy of dystrophin localization in guinea pig skeletal muscle fibers

    OpenAIRE

    1992-01-01

    A confocal laser microscope was used to analyze the localization pattern of dystrophin along the sarcolemma in guinea pig skeletal muscle fibers. Hind leg muscles of the normal animals were freshly dissected and frozen for cryostat sections, which were then stained with a monoclonal antidystrophin antibody. In confocal laser microscopy, immunofluorescence staining in relatively thick sections could be sharply imaged in thin optical sections. When longitudinal and transverse sections of muscle...

  12. Differences in Muscle Fiber Recruitment Patterns between Continuous and Interval Exercises

    OpenAIRE

    YAMANO, Seiko; Kawai, Minako; MINAMI, Yoshio; HIRAGA, Atsushi; MIYATA, Hirofumi

    2011-01-01

    We evaluated differences in muscle fiber recruitment patterns between continuous and interval training to develop an optimal training program for Thoroughbred horses. Five well trained female thoroughbred horses (3–4 years old) were used. The horses performed two different exercises on a 10% inclined treadmill: 90%VO2 max for 4 min (continuous) and 90% VO2 max for 2 min × 2 times with 10-min interval (interval). Muscle samples were obtained from the middle gluteal muscle before and immediatel...

  13. Regulation of exercise-induced fiber type transformation, mitochondrial biogenesis, and angiogenesis in skeletal muscle

    OpenAIRE

    Yan, Zhen; Okutsu, Mitsuharu; Akhtar, Yasir N.; Lira, Vitor A.

    2010-01-01

    Skeletal muscle exhibits superb plasticity in response to changes in functional demands. Chronic increases of skeletal muscle contractile activity, such as endurance exercise, lead to a variety of physiological and biochemical adaptations in skeletal muscle, including mitochondrial biogenesis, angiogenesis, and fiber type transformation. These adaptive changes are the basis for the improvement of physical performance and other health benefits. This review focuses on recent findings in genetic...

  14. Foxj3 transcriptionally activates Mef2c and regulates adult skeletal muscle fiber type identity

    OpenAIRE

    Alexander, Matthew S.; Shi, Xiaozhong; Voelker, Kevin A.; Grange, Robert W.; Garcia, Joseph A.; Robert E Hammer; Garry, Daniel J

    2009-01-01

    The mechanisms that regulate skeletal muscle differentiation, fiber type diversity and muscle regeneration are incompletely defined. Forkhead transcription factors are critical regulators of cellular fate determination, proliferation, and differentiation. We identified a forkhead/winged helix transcription factor, Foxj3, which was expressed in embryonic and adult skeletal muscle. To define the functional role of Foxj3, we examined Foxj3 mutant mice. Foxj3 mutant mice are viable but have signi...

  15. Size and myonuclear domains in Rhesus soleus muscle fibers: short-term spaceflight

    Science.gov (United States)

    Roy, R. R.; Zhong, H.; Talmadge, R. J.; Bodine, S. C.; Fanton, J. W.; Koslovskaya, I.; Edgerton, V. R.

    2001-01-01

    The cross-sectional area (CSA), myonuclear number per mm of fiber length, and myonuclear domain (cytoplasmic volume/myonucleus) of mechanically isolated single fibers from biopsies of the soleus muscle of 5 vivarium control, 3 flight simulation and 2 flight (BION 11) Rhesus monkeys (Macaca [correction of Macacca] mulatta) were determined using confocal microscopy before and after a 14-day experimental period. Simulation monkeys were confined in chairs placed in capsules identical to those used during the flight. Fibers were classified as type I, type II or hybrid (containing both types I and II) based on myosin heavy chain (MHC) gel electrophoresis. A majority of the fibers sampled contained only type I MHC, i.e. 89, 62 and 68% for the control, simulation and flight groups, respectively. Most of the remaining fibers were hybrids, i.e. 8, 36 and 32% for the same groups. There were no significant pre-post differences in the fiber type composition for any of the experimental groups. There also were no significant pre-post differences in fiber CSA, myonuclear number or myonuclear domain. There was, however, a tendency for the fibers in the post-flight biopsies to have a smaller mean CSA and myonuclear domain (approximately 10%, p=0.07) than the fibers in the pre-flight biopsy. The combined mean cytoplasmic volume/myonucleus for all muscle fiber phenotypes in the Rhesus soleus muscle was approximately 25,000 micrometers3 and there were no differences in pre-post samples for the control and simulated groups. The cytoplasmic domains tended to be lower (p=0.08) after than before flight. No phenotype differences in cytoplasmic domains were observed. These data suggest that after a relatively short period of actual spaceflight, modest fiber atrophy occurs in the soleus muscle fibers without a concomitant change in myonuclear number.

  16. Elastic properties of relaxed, activated, and rigor muscle fibers measured with microsecond resolution

    OpenAIRE

    Jung, D.W.G.; Blangé, T; Graaf, van der, H.; Treijtel, B.W.

    1988-01-01

    Tension responses due to small and rapid length changes (completed within 40 microseconds) were obtained from skinned single-fiber segments (4- to 7-mm length) of the iliofibularis muscle of the frog incubated in relaxing, rigor, and activating solution. The fibers were skinned by freeze-drying. The first 500 microseconds of the responses for all three conditions could be described with a linear model, in which the fiber is regarded as a rod composed of infinitesimally small identical segment...

  17. Fiber size and myosin phenotypes of selected rhesus lower limb muscles after a 14-day spaceflight

    Science.gov (United States)

    Roy, R. R.; Zhong, H.; Bodine, S. C.; Pierotti, D. J.; Talmadge, R. J.; Barkhoudarian, G.; Kim, J.; Fanton, J. W.; Kozlovskaya, I. B.; Edgerton, V. R.

    2000-01-01

    Muscle biopsies were taken from the rhesus (Macaca mulatta) soleus (Sol, a slow ankle extensor), medial gastrocnemius (MG, a fast ankle extensor), tibialis anterior (TA, a fast ankle flexor), and vastus lateralis (VL, a fast knee extensor) muscles in vivarium controls (n=5) before and after either a 14-day spaceflight (Bion 11, n=2) or a 14-day ground-based flight simulation (n=3). Myosin heavy chain (MHC) composition (gel electrophoresis), fiber type distribution (immunohistochemistry), and fiber size were determined. Although there were no significant changes, each muscle showed trends towards adaptation.

  18. Characterization of Fiber Types in Different Muscles of the Hindlimb in Female Weanling and Adult Wistar Rats

    International Nuclear Information System (INIS)

    We analyzed lesser diameter and distribution of fiber types in different skeletal muscles from female Wistar rats using a histoenzymology Myofibrillar Adenosine Tri-phosphatase (mATPase) method. Fragments from muscles were frozen and processed by mATPase in different pH. Adult and weanling rat soleus muscles presented a predominance of type I fibers and larger fiber diameters. In the plantar muscle in adult rats, the type IIB fibers demonstrated greater lesser diameter while in the weanling animals, types I and IIB fibers were larger. The plantar muscle of animals of both ages was composed predominantly of the type IID fibers. The type IID fibers were observed in similar amounts in the lateral gastrocnemius and the medial gastrocnemius muscles. Type IIB fibers showed predominance and presented higher size in comparison with other types in the EDL muscle. The present study shows that data on fiber type distribution and fiber lesser diameter obtained in adult animals cannot always be applied to weanling animals of the same species. Using the mATPase, despite the difficult handling, is an important tool to determine the different characteristics of the specific fibers in the skeletal muscle tissue

  19. The role of nitric oxide in muscle fibers with oxidative phosphorylation defects

    International Nuclear Information System (INIS)

    NO has been pointed as an important player in the control of mitochondrial respiration, especially because of its inhibitory effect on cytochrome c oxidase (COX). However, all the events involved in this control are still not completely elucidated. We demonstrate compartmentalized abnormalities on nitric oxide synthase (NOS) activity on muscle biopsies of patients with mitochondrial diseases. NOS activity was reduced in the sarcoplasmic compartment in COX deficient fibers, whereas increased activity was found in the sarcolemma of fibers with mitochondrial proliferation. We observed increased expression of neuronal NOS (nNOS) in patients and a correlation between nNOS expression and mitochondrial content. Treatment of skeletal muscle culture with an NO donor induced an increase in mitochondrial content. Our results indicate specific roles of NO in compensatory mechanisms of muscle fibers with mitochondrial deficiency and suggest the participation of nNOS in the signaling process of mitochondrial proliferation in human skeletal muscle

  20. Contractile function of single muscle fibers after hindlimb suspension

    Science.gov (United States)

    Gardetto, P. R.; Schluter, J. M.; Fitts, R. H.

    1989-01-01

    The effects of two weeks of hind-limb suspension (HS) on the functional properties of slow-twitch and fast-twitch single fibers isolated from the predominantly slow-twitch soleus and fast-twitch gastrocnemius of the suspended leg of rats were investigated. Single fibers were suspended between a motor arm and force transducer, and, after their functional properties were studied, the fiber type was established by the myosin heavy chain analysis. It was found that, after HS, the greatest decrease in diameter and a reduction in peak tension occurred in slow-twitch fibers from soleus, followed by slow-twitch fibers from gastrocnemius. Fast-twitch fibers from the red gastrocnemius showed a significant reduction in diameter but no change in peak tension. No effect of HS was observed on the diameter of the fast-twitch fibers from the white gastsrocnemius (which is known to contain 87 percent fast glycolytic fibers).

  1. Spaceflight and growth effects on muscle fibers in the rhesus monkey

    Science.gov (United States)

    Bodine-Fowler, Sue C.; Roy, Roland R.; Rudolph, William; Haque, Naz; Kozlovskaia, Inessa B.; Edgerton, V. R.

    1992-01-01

    The effect of a 14-day spaceflight onboard Cosmos 2044 on selected morphological and metabolic properties of single muscle fibers was investigated in a nonhuman primate, Macaca mulatta. It is concluded that the 14-day spaceflight had little impact on fiber size in the soleus (S) and medial gastrocnemius (MG) muscles, whereas it appeared to be a slight decrease in sized in the tibialis anterior (TA). The mean fiber size in the postflight biopsies increased relative to preflight values. The mean fiber succinate dehydrogenase activity was found to decrease in the MG, whereas there was no apparent effect of spaceflight on the s and ta muscles. The differences in response of the S, MG, and TA to spaceflight in monkeys vs rats may be related to a species responsiveness to spaceflight, the manner in which the animals were restrained, and/or the possibility that the ankle musculature was able to function against a load while in space.

  2. Type II muscle fibers atrophy associated with silent corticotroph adenoma in a dog.

    Directory of Open Access Journals (Sweden)

    L Insabato

    2010-11-01

    Full Text Available The Silent Corticotroph Adenoma (SCA is a pituitary adenoma variant characterized by the immunoreactivity for adrenocorticotropic hormone (ACTH and related peptides, without the clinical signs of Cushing's disease. SCA has been postulated to either secrete structurally abnormal ACTH that is inactive but detectable by immunohistochemistry or radioimmunoassay, or to secrete ACTH intermittently or at low levels continuously. Excess of ACTH has been associated to type II muscle atrophy. We describe a case of type II muscle fibers atrophy associated with silent corticotroph adenoma in a dog. The dog showed moderate to severe proximal muscle wasting and weakness with normal levels of muscle-associated enzymes. In the limb muscle biopsies, type II fibers were uniformly smaller than type I fibers. In temporalis muscles, there were few atrophic fibers, and several irregular areas of loss of enzymatic activity observed in NADH, SDH and COX stains. The tumour showed a trabecular growth pattern and immunohistochemical analysis demonstrated the presence of cytoplasmic immunoreactivity for ACTH. The muscle atrophy was considered to be related to an excess of inactive ACTH. Studying spontaneous occurring rare diseases in animals could help to understand the mechanism of similar diseases in human has well.

  3. Effects of disuse by limb immobilization on different muscle fiber types

    Science.gov (United States)

    Booth, F. W.; Seider, M. J.; Hugman, G. R.

    1980-01-01

    The effects of disuse by limb immobilization on different muscle fiber types are reviewed. It is demonstrated that many changes occurring in atrophying skeletal muscles of young rats can be explained by the duration of the half-lives of muscle proteins. Differences are found to exist in responses of fast- and slow-twitch muscles due to disuse atrophy, and the appearance of plasticity in skeletal muscle begins to occur very soon after changes in the level of contractile activity. Rates of protein degradation increase in slow-twitch muscles at rapidly growing rates after approximately one day of limb immobilization; however, no change in the rates of protein degradation is noted in fast-twitch muscles of young rats.

  4. Mechanical muscle function, morphology, and fiber type in lifelong trained elderly

    DEFF Research Database (Denmark)

    Aagaard, Per; Magnusson, Peter S; Larsson, Benny;

    2007-01-01

    PURPOSE: Maximal muscle contraction force and muscle mass are both reduced during the natural aging process. Long-term training may be used to attenuate this age-related loss in muscle function and muscle size. METHODS: Maximum isometric quadriceps strength (MVC), rate of force development (RFD...... (i.e., lifelong) strength training. This relative preservation in muscle morphology and function may provide an important physical reserve capacity to retain muscle mass and function above the critical threshold for independent living at old age.......), and muscle fiber composition and size (CSA) were studied in elderly individuals (68-78 yr) chronically exposed (> 50 yr) to either endurance (E) or strength (S) training, and in age-matched, untrained (U) elderly group. RESULTS: E and S showed greater MVC than did U. Contractile RFD was elevated in S...

  5. Electrophysiological characteristics of motor units and muscle fibers in trained and untrained young male subjects

    DEFF Research Database (Denmark)

    Duez, Lene; Qerama, Erisela; Fuglsang-Frederiksen, Anders;

    2010-01-01

    We hypothesized that the amplitudes of compound muscle action potentials (CMAPs) and interference pattern analysis (IPA) would be larger in trained subjects compared with untrained subjects, possibly due to hypertrophy of muscle fibers and/or increased central drive. Moreover, we hypothesized...... that the untrained muscle is less excitable compared with the trained muscle. An electromyographic (EMG) needle electrode was used to record the IPA at maximal voluntary effort. The CMAP was obtained by stimulating the musculocutaneous nerve and recording the brachial biceps muscle using surface electrodes. CMAPs...... were obtained by direct muscle stimulation (DMS) with two stainless-steel subdermal electrodes placed subcutaneously in the distal third of the muscle. Amplitudes of CMAP and IPA were significantly larger in trained subjects compared with untrained subjects. We found no differences between trained...

  6. Altered distribution of mitochondria in rat soleus muscle fibers after spaceflight

    Science.gov (United States)

    Bell, Gordon J.; Martin, Thomas P.; Il'ina-Kakueva, E. I.; Oganov, V. S.; Edgerton, V. R.

    1992-01-01

    The effect of an exposure to microgravity on the distribution of the succinate dehydrogenase (SDH) activity throughout the soleus muscle fibers was investigated by measuring SDH activity throughout the cross section of 20-30 fibers each of the slow-twitch oxidative and fast-twitch oxidative-glycolytic types of fibers in rats exposed to 12.5 days in space aboard Cosmos 1887. It was found that, after the spaceflight, the entire regional distribution of SDH activity was significantly altered (as compared to ground controls) in the slow-twitch oxidative fibers, whereas the fast-twitch oxidative-glycolytic fibers from muscles of flown rats exhibited a significantly lower SDH activity only in their subsarcolemmal region.

  7. Adaptation of fibers in fast-twitch muscles of rats to spaceflight and hindlimb suspension

    Science.gov (United States)

    Jiang, Bian; Ohira, Yoshi; Roy, Roland R.; Nguyen, Quyet; Il'ina-Kakueva, E. I.; Oganov, V.; Edgerton, V. R.

    1992-01-01

    The adaptation of single fibers in medial gastrocnemius (MG), a fast-twitch extensor, and in tibialis anterior (TA), a fast-twitch flexor, was studied after 14 days of spaceflight onboard Cosmos 2044 or hindlimb suspension. Quantitative myosin ATPase activities of single fibers were measured in flight and suspended rats. Each of the enzyme and size measurements were directly correlated within each fiber with respect to its qualitative myosin ATPase staining properties and its expression of fast, slow, or both myosin heavy chains (MHC). The percentage of slow- and fast-twitch fibers of the MG and TA were found to be unchanged. Mean fiber size of all fibers was unaffected after flight or suspension. The ATPase activity in the MG was higher in flight than in control or suspended rats. In comparison to Cosmos 1887 spaceflight, the adaptations in the muscle fibers of the MG were more moderate.

  8. Intracellular calcium movements during excitation–contraction coupling in mammalian slow-twitch and fast-twitch muscle fibers

    OpenAIRE

    Baylor, Stephen M.; Hollingworth, Stephen

    2012-01-01

    In skeletal muscle fibers, action potentials elicit contractions by releasing calcium ions (Ca2+) from the sarcoplasmic reticulum. Experiments on individual mouse muscle fibers micro-injected with a rapidly responding fluorescent Ca2+ indicator dye reveal that the amount of Ca2+ released is three- to fourfold larger in fast-twitch fibers than in slow-twitch fibers, and the proportion of the released Ca2+ that binds to troponin to activate contraction is substantially smaller.

  9. Evidence for myoblast-extrinsic regulation of slow myosin heavy chain expression during muscle fiber formation in embryonic development

    OpenAIRE

    1993-01-01

    Vertebrate muscles are composed of an array of diverse fast and slow fiber types with different contractile properties. Differences among fibers in fast and slow MyHC expression could be due to extrinsic factors that act on the differentiated myofibers. Alternatively, the mononucleate myoblasts that fuse to form multinucleated muscle fibers could differ intrinsically due to lineage. To distinguish between these possibilities, we determined whether the changes in proportion of slow fibers were...

  10. Mechanical and Electrophysiological Properties of the Sarcolemma of Muscle Fibers in Two Murine Models of Muscle Dystrophy: Col6a1−/− and Mdx

    OpenAIRE

    Canato, M.; Dal Maschio, M.; Sbrana, F.; R. Raiteri; C. Reggiani; Vassanelli, S.; A. Megighian

    2010-01-01

    This study aimed to analyse the sarcolemma of Col6a1−/− fibers in comparison with wild type and mdx fibers, taken as positive control in view of the known structural and functional alterations of their membranes. Structural and mechanical properties were studied in single muscle fibers prepared from FDB muscle using atomic force microscopy (AFM) and conventional electrophysiological techniques to measure ionic conductance and capacitance. While the sarcolemma topography was pres...

  11. The Masticatory Contractile Load Induced Expression and Activation of Akt1/PKBα in Muscle Fibers at the Myotendinous Junction within Muscle-Tendon-Bone Unit

    Directory of Open Access Journals (Sweden)

    Yüksel Korkmaz

    2010-01-01

    Full Text Available The cell specific detection of enzyme activation in response to the physiological contractile load within muscle-tendon-bone unit is essential for understanding of the mechanical forces transmission from muscle cells via tendon to the bone. The hypothesis that the physiological mechanical loading regulates activation of Akt1/PKBα at Thr308 and at Ser473 in muscle fibers within muscle-tendon-bone unit was tested using quantitative immunohistochemistry, confocal double fluorescence analysis, and immunoblot analysis. In comparison to the staining intensities in peripheral regions of the muscle fibers, Akt1/PKBα was detected with a higher staining intensity in muscle fibers at the myotendinous junction (MTJ areas. In muscle fibers at the MTJ areas, Akt1/PKBα is dually phosphorylated at Thr308 and Ser473. The immunohistochemical results were confirmed by immunoblot analysis. We conclude that contractile load generated by masticatory muscles induces local domain-dependent expression of Akt1/PKBα as well as activation by dually phosphorylation at Thr308 and Ser473 in muscle fibers at the MTJ areas within muscle-tendon-bone unit.

  12. Spaceflight effects on single skeletal muscle fiber function in the rhesus monkey

    Science.gov (United States)

    Fitts, R. H.; Desplanches, D.; Romatowski, J. G.; Widrick, J. J.

    2000-01-01

    The purpose of this investigation was to understand how 14 days of weightlessness alters the cellular properties of individual slow- and fast-twitch muscle fibers in the rhesus monkey. The diameter of the soleus (Sol) type I, medial gastrocnemius (MG) type I, and MG type II fibers from the vivarium controls averaged 60 +/- 1, 46 +/- 2, and 59 +/- 2 microm, respectively. Both a control 1-G capsule sit (CS) and spaceflight (SF) significantly reduced the Sol type I fiber diameter (20 and 13%, respectively) and peak force, with the latter declining from 0.48 +/- 0.01 to 0.31 +/- 0.02 (CS group) and 0.32 +/- 0.01 mN (SF group). When the peak force was expressed as kiloNewtons per square meter (kN/m(2)), only the SF group showed a significant decline. This group also showed a significant 15% drop in peak fiber stiffness that suggests that fewer cross bridges were contracting in parallel. In the MG, SF but not CS depressed the type I fiber diameter and force. Additionally, SF significantly depressed absolute (mN) and relative (kN/m(2)) force in the fast-twitch MG fibers by 30% and 28%, respectively. The Ca(2+) sensitivity of the type I fiber (Sol and MG) was significantly reduced by growth but unaltered by SF. Flight had no significant effect on the mean maximal fiber shortening velocity in any fiber type or muscle. The post-SF Sol type I fibers showed a reduced peak power and, at peak power, an elevated velocity and decreased force. In conclusion, CS and SF caused atrophy and a reduced force and power in the Sol type I fiber. However, only SF elicited atrophy and reduced force (mN) in the MG type I fiber and a decline in relative force (kN/m(2)) in the Sol type I and MG type II fibers.

  13. Size and metabolic properties of fibers in rat fast-twitch muscles after hindlimb suspension

    Science.gov (United States)

    Roy, Roland R.; Bello, Maureen A.; Bouissou, Phillip; Edgerton, V. Reggie

    1987-01-01

    The effect of hind-limb suspension (HS) on single fibers of the medial gastrocnemius (MG) and the tibialis anterior (TA) muscles were studied in rats. Fiber area and the activities of succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) were determined in tissue sections using an image analysis system. After 28 days of HS, the MG atrophied 28 percent, whereas the TA weight was maintained. Both dark- and light-ATPase fibers in the deep region of the MG had decreased cross-sectional areas following HS, with the atrophic response being twice as great in the light-ATPase fibers than in the dark-ATPase fibers. Following HS, mean SDH activities of both fiber types were significantly lower in the MG and TA than in the CON; by contrast, mean GPD activities were either maintained at the CON level or were higher in both MG and TA muscles. The data suggest an independence of the mechanisms determining the muscle fiber size and the metabolic adaptations associated with HS.

  14. Bion 11 Spaceflight Project: Effect of Weightlessness on Single Muscle Fiber Function in Rhesus Monkeys

    Science.gov (United States)

    Fitts, Robert H.; Romatowski, Janell G.; Widrick, Jeffrey J.; DeLaCruz, Lourdes

    1999-01-01

    Although it is well known that microgravity induces considerable limb muscle atrophy, little is known about how weightlessness alters cell function. In this study, we investigated how weightlessness altered the functional properties of single fast and slow striated muscle fibers. Physiological studies were carried out to test the hypothesis that microgravity causes fiber atrophy, a decreased peak force (Newtons), tension (Newtons/cross-sectional area) and power, an elevated peak rate of tension development (dp/dt), and an increased maximal shortening velocity (V(sub o)) in the slow type I fiber, while changes in the fast-twitch fiber are restricted to atrophy and a reduced peak force. For each fiber, we determined the peak force (P(sub o)), V(sub o), dp/dt, the force-velocity relationship, peak power, the power-force relationship, the force-pCa relationship, and fiber stiffness. Biochemical studies were carried out to assess the effects of weightlessness on the enzyme and substrate profile of the fast- and slow-twitch fibers. We predicted that microgravity would increase resting muscle glycogen and glycolytic metabolism in the slow fiber type, while the fast-twitch fiber enzyme profile would be unaltered. The increased muscle glycogen would in part result from an elevated hexokinase and glycogen synthase. The enzymes selected for study represent markers for mitochondrial function (citrate synthase and 0-hydroxyacyl-CoA dehydrogenase), glycolysis (Phosphofructokinase and lactate dehydrogenase), and fatty acid transport (Carnitine acetyl transferase). The substrates analyzed will include glycogen, lactate, adenosine triphosphate, and phosphocreatine.

  15. AHNAK1 and AHNAK2 are costameric proteins: AHNAK1 affects transverse skeletal muscle fiber stiffness

    International Nuclear Information System (INIS)

    Research highlights: → AHNAK1 and AHNAK2 are costameric proteins. → Intact membrane repair in AHNAK1-deficient mice. → AHNAK1-/- single fibers have a higher transverse stiffness. -- Abstract: The AHNAK scaffold PDZ-protein family is implicated in various cellular processes including membrane repair; however, AHNAK function and subcellular localization in skeletal muscle are unclear. We used specific AHNAK1 and AHNAK2 antibodies to analyzed the detailed localization of both proteins in mouse skeletal muscle. Co-localization of AHNAK1 and AHNAK2 with vinculin clearly demonstrates that both proteins are components of the costameric network. In contrast, no AHNAK expression was detected in the T-tubule system. A laser wounding assay with AHNAK1-deficient fibers suggests that AHNAK1 is not involved in membrane repair. Using atomic force microscopy (AFM), we observed a significantly higher transverse stiffness of AHNAK1-/- fibers. These findings suggest novel functions of AHNAK proteins in skeletal muscle.

  16. Velocity, force, power, and Ca2+ sensitivity of fast and slow monkey skeletal muscle fibers

    Science.gov (United States)

    Fitts, R. H.; Bodine, S. C.; Romatowski, J. G.; Widrick, J. J.

    1998-01-01

    In this study, we determined the contractile properties of single chemically skinned fibers prepared from the medial gastrocnemius (MG) and soleus (Sol) muscles of adult male rhesus monkeys and assessed the effects of the spaceflight living facility known as the experiment support primate facility (ESOP). Muscle biopsies were obtained 4 wk before and immediately after an 18-day ESOP sit, and fiber type was determined by immunohistochemical techniques. The MG slow type I fiber was significantly smaller than the MG type II, Sol type I, and Sol type II fibers. The ESOP sit caused a significant reduction in the diameter of type I and type I/II (hybrid) fibers of Sol and MG type II and hybrid fibers but no shift in fiber type distribution. Single-fiber peak force (mN and kN/m2) was similar between fiber types and was not significantly different from values previously reported for other species. The ESOP sit significantly reduced the force (mN) of Sol type I and MG type II fibers. This decline was entirely explained by the atrophy of these fiber types because the force per cross-sectional area (kN/m2) was not altered. Peak power of Sol and MG fast type II fiber was 5 and 8.5 times that of slow type I fiber, respectively. The ESOP sit reduced peak power by 25 and 18% in Sol type I and MG type II fibers, respectively, and, for the former fiber type, shifted the force-pCa relationship to the right, increasing the Ca2+ activation threshold and the free Ca2+ concentration, eliciting half-maximal activation. The ESOP sit had no effect on the maximal shortening velocity (Vo) of any fiber type. Vo of the hybrid fibers was only slightly higher than that of slow type I fibers. This result supports the hypothesis that in hybrid fibers the slow myosin heavy chain would be expected to have a disproportionately greater influence on Vo.

  17. De novo synthesis of adenine nucleotides in different skeletal muscle fiber types

    International Nuclear Information System (INIS)

    Management of adenine nucleotide catabolism differs among skeletal muscle fiber types. This study evaluated whether there are corresponding differences in the rates of de novo synthesis of adenine nucleotide among fiber type sections of skeletal muscle using an isolated perfused rat hindquarter preparation. Label incorporation into adenine nucleotides from the [1-14C]glycine precursor was determined and used to calculate synthesis rates based on the intracellular glycine specific radioactivity. Results show that intracellular glycine is closely related to the direct precursor pool. Rates of de novo synthesis were highest in fast-twitch red muscle (57.0 +/- 4.0, 58.2 +/- 4.4 nmol.h-1.g-1; deep red gastrocnemius and vastus lateralis), relatively high in slow-twitch red muscle (47.0 +/- 3.1; soleus), and low in fast-twitch white muscle (26.1 +/- 2.0 and 21.6 +/- 2.3; superficial white gastrocnemius and vastus lateralis). Rates for four mixed muscles were intermediate, ranging between 32.3 and 37.3. Specific de novo synthesis rates exhibited a strong correlation (r = 0.986) with muscle section citrate synthase activity. Turnover rates (de novo synthesis rate/adenine nucleotide pool size) were highest in high oxidative muscle (0.82-1.06%/h), lowest in low oxidative muscle (0.30-0.35%/h), and intermediate in mixed muscle (0.44-0.55%/h). Our results demonstrate that differences in adenine nucleotide management among fiber types extends to the process of de novo adenine nucleotide synthesis

  18. Hierarchically buckled sheath-core fibers for superelastic electronics, sensors, and muscles

    Science.gov (United States)

    Liu, Z. F.; Fang, S.; Moura, F. A.; Ding, J. N.; Jiang, N.; Di, J.; Zhang, M.; Lepró, X.; Galvão, D. S.; Haines, C. S.; Yuan, N. Y.; Yin, S. G.; Lee, D. W.; Wang, R.; Wang, H. Y.; Lv, W.; Dong, C.; Zhang, R. C.; Chen, M. J.; Yin, Q.; Chong, Y. T.; Zhang, R.; Wang, X.; Lima, M. D.; Ovalle-Robles, R.; Qian, D.; Lu, H.; Baughman, R. H.

    2015-07-01

    Superelastic conducting fibers with improved properties and functionalities are needed for diverse applications. Here we report the fabrication of highly stretchable (up to 1320%) sheath-core conducting fibers created by wrapping carbon nanotube sheets oriented in the fiber direction on stretched rubber fiber cores. The resulting structure exhibited distinct short- and long-period sheath buckling that occurred reversibly out of phase in the axial and belt directions, enabling a resistance change of less than 5% for a 1000% stretch. By including other rubber and carbon nanotube sheath layers, we demonstrated strain sensors generating an 860% capacitance change and electrically powered torsional muscles operating reversibly by a coupled tension-to-torsion actuation mechanism. Using theory, we quantitatively explain the complementary effects of an increase in muscle length and a large positive Poisson’s ratio on torsional actuation and electronic properties.

  19. Neutron fiber diffraction of frog muscle with the contrast variation measurements

    International Nuclear Information System (INIS)

    Neutron scattering and diffraction has a unique ability that information on variation of scattering length density of a particle can be obtained by applying the 'contrast variation' method. Here we applied this method to fiber diffraction. Neutron fiber diffraction patterns of 'live' frog muscle, perfused with Ringer's solution containing a various amount of D2O, were measured with the small-angle scattering instrument, SANS-J, of JAERI. Analysis of the contrast dependence of the amplitude of each reflection showed that there is definite variation of the scattering length density within the fibrous protein complexes in muscle. (author)

  20. The Masticatory Contractile Load Induced Expression and Activation of Akt1/PKBα in Muscle Fibers at the Myotendinous Junction within Muscle-Tendon-Bone Unit

    OpenAIRE

    Yüksel Korkmaz; Franz J. Klinz; Mehrnoush Moghbeli; Klaus Addicks; Wolfgang H.-M. Raab; Wilhelm Bloch

    2010-01-01

    The cell specific detection of enzyme activation in response to the physiological contractile load within muscle-tendon-bone unit is essential for understanding of the mechanical forces transmission from muscle cells via tendon to the bone. The hypothesis that the physiological mechanical loading regulates activation of Akt1/PKBα at Thr308 and at Ser473 in muscle fibers within muscle-tendon-bone unit was tested using quantitative immunohistochemistry, confocal double fluorescence analy...

  1. Degeneration of oxidative muscle fibers in HTLV-1 tax transgenic mice.

    OpenAIRE

    Nerenberg, M I; Wiley, C A

    1989-01-01

    The HTLV-1 tax gene under control of the HTLV-1 long terminal repeat (LTR) was introduced into transgenic mice. Previously tax protein expression in the muscle and peripheral nerves of three independent mouse lines was reported. Here the localization of this transgenic protein at a cellular and subcellular level is described. Tax protein was expressed in oxidative muscle fibers that developed severe progressive atrophy. It localized to the cytoplasma where it was associated with structures re...

  2. Influence of ionic strength on the actomyosin reaction steps in contracting skeletal muscle fibers.

    OpenAIRE

    Iwamoto, H

    2000-01-01

    Muscle contraction occurs as the result of actin-myosin interaction, which is mediated by the intermolecular forces exerted at the actin-myosin interface. To obtain information about the nature of these intermolecular forces, we tested the sensitivity of various contractile parameters of skinned skeletal muscle fibers to ionic strength (IS) at 3-5 degrees C; IS variation is a useful technique for distinguishing between ionic and nonionic (primarily hydrophobic) types of intermolecular forces....

  3. Is functional hypertrophy and specific force coupled with the addition of myonuclei at the single muscle fiber level?

    OpenAIRE

    Qaisar, R.; Renaud, G; Morine, K.; Barton, E. R.; Sweeney, H. L.; Larsson, L

    2012-01-01

    Muscle force is typically proportional to muscle size, resulting in constant force normalized to muscle fiber cross-sectional area (specific force). Mice overexpressing insulin-like growth factor-1 (IGF-1) exhibit a proportional gain in muscle force and size, but not the myostatin-deficient mice. In an attempt to explore the role of the cytoplasmic volume supported by individual myonuclei [myonuclear domain (MND) size] on functional capacity of skeletal muscle, we have investigated specific f...

  4. Eccentric contraction-induced injury to type I, IIa, and IIa/IIx muscle fibers of elderly adults

    Science.gov (United States)

    Muscles of old laboratory rodents experience exaggerated force losses after eccentric contractile activity. We extended this line of inquiry to humans and investigated the influence of fiber myosin heavy chain (MHC) isoform content on the injury process. Skinned muscle fiber segments, prepared from ...

  5. Function and position determine relative proportions of different fiber types in limb muscles of the lizard Tropidurus psammonastes.

    Science.gov (United States)

    Pereira, Anieli G; Abdala, Virginia; Kohlsdorf, Tiana

    2015-02-01

    Skeletal muscles can be classified as flexors or extensors according to their function, and as dorsal or ventral according to their position. The latter classification evokes their embryological origin from muscle masses initially divided during limb development, and muscles sharing a given position do not necessarily perform the same function. Here, we compare the relative proportions of different fiber types among six limb muscles in the lizard Tropidurus psammonastes. Individual fibers were classified as slow oxidative (SO), fast glycolytic (FG) or fast oxidative-glycolytic (FOG) based on mitochondrial content; muscles were classified according to position and function. Mixed linear models considering one or both effects were compared using likelihood ratio tests. Variation in the proportion of FG and FOG fibers is mainly explained by function (flexor muscles have on average lower proportions of FG and higher proportions of FOG fibers), while variation in SO fibers is better explained by position (they are less abundant in ventral muscles than in those developed from a dorsal muscle mass). Our results clarify the roles of position and function in determining the relative proportions of the various muscle fibers and provide evidence that these factors may differentially affect distinct fiber types. PMID:25456976

  6. Isolation and characterization of an avian slow myosin heavy chain gene expressed during embryonic skeletal muscle fiber formation.

    Science.gov (United States)

    Nikovits, W; Wang, G F; Feldman, J L; Miller, J B; Wade, R; Nelson, L; Stockdale, F E

    1996-07-19

    We have isolated and begun characterization of the quail slow myosin heavy chain (MyHC) 3 gene, the first reported avian slow MyHC gene. Expression of slow MyHC 3 in skeletal muscle is restricted to the embryonic period of development, when the fiber pattern of future fast and slow muscle is established. In embryonic hindlimb development, slow MyHC 3 gene expression coincides with slow muscle fiber formation as distinguished by slow MyHC-specific antibody staining. In addition to expression in embryonic appendicular muscle, slow MyHC 3 is expressed continuously in the atria. Transfection of slow MyHC 3 promoter-reporter constructs into embryonic myoblasts that form slow MyHC-expressing fibers identified two regions regulating expression of this gene in skeletal muscle. The proximal promoter, containing potential muscle-specific regulatory motifs, permits expression of a reporter gene in embryonic slow muscle fibers, while a distal element, located greater than 2600 base pairs upstream, further enhances expression 3-fold. The slow muscle fiber-restricted expression of slow MyHC 3 during embryonic development, and expression of slow MyHC 3 promoter-reporter constructs in embryonic muscle fibers in vitro, makes this gene a useful marker to study the mechanism establishing the slow fiber lineage in the embryo. PMID:8663323

  7. The expression of HSP in human skeletal muscle. Effects of muscle fiber phenotype and training background

    DEFF Research Database (Denmark)

    Folkesson, Mattias; Mackey, Abigail L; Langberg, Henning;

    2013-01-01

    AIM: Exercise-induced adaptations of skeletal muscle are related to training mode and can be muscle fibre type specific. This study aimed to investigate heat shock protein expression in type I and type II muscle fibres in resting skeletal muscle of subjects with different training backgrounds...... HSPs in human skeletal muscle is influenced by muscle fibre phenotype. The fibre type specific expression of HSP70 is influenced by resistance and endurance training whereas those of αB-crystallin and HSP27 are influenced only by endurance training suggesting the existence of a training......-modality specific action on the adaptive processes including heat shock proteins in human skeletal muscle. This article is protected by copyright. All rights reserved....

  8. Measuring mitochondrial respiration in intact single muscle fibers

    OpenAIRE

    Schuh, Rosemary A; Jackson, Kathryn C.; Khairallah, Ramzi J.; Ward, Christopher W.; Spangenburg, Espen E.

    2011-01-01

    Measurement of mitochondrial function in skeletal muscle is a vital tool for understanding regulation of cellular bioenergetics. Currently, a number of different experimental approaches are employed to quantify mitochondrial function, with each involving either mechanically or chemically induced disruption of cellular membranes. Here, we describe a novel approach that allows for the quantification of substrate-induced mitochondria-driven oxygen consumption in intact single skeletal muscle fib...

  9. Protein Supplementation Does Not Further Increase Latissimus Dorsi Muscle Fiber Hypertrophy after Eight Weeks of Resistance Training in Novice Subjects, but Partially Counteracts the Fast-to-Slow Muscle Fiber Transition

    Directory of Open Access Journals (Sweden)

    Antonio Paoli

    2016-06-01

    Full Text Available The response to resistance training and protein supplementation in the latissimus dorsi muscle (LDM has never been investigated. We investigated the effects of resistance training (RT and protein supplementation on muscle mass, strength, and fiber characteristics of the LDM. Eighteen healthy young subjects were randomly assigned to a progressive eight-week RT program with a normal protein diet (NP or high protein diet (HP (NP 0.85 vs. HP 1.8 g of protein·kg−1·day−1. One repetition maximum tests, magnetic resonance imaging for cross-sectional muscle area (CSA, body composition, and single muscle fibers mechanical and phenotype characteristics were measured. RT induced a significant gain in strength (+17%, p < 0.0001, whole muscle CSA (p = 0.024, and single muscle fibers CSA (p < 0.05 of LDM in all subjects. Fiber isometric force increased in proportion to CSA (+22%, p < 0.005 and thus no change in specific tension occurred. A significant transition from 2X to 2A myosin expression was induced by training. The protein supplementation showed no significant effects on all measured outcomes except for a smaller reduction of 2X myosin expression. Our results suggest that in LDM protein supplementation does not further enhance RT-induced muscle fiber hypertrophy nor influence mechanic muscle fiber characteristics but partially counteracts the fast-to-slow fiber shift.

  10. Phosphate and acidosis act synergistically to depress peak power in rat muscle fibers

    OpenAIRE

    Nelson, Cassandra R.; Debold, Edward P.; Fitts, Robert H.

    2014-01-01

    Skeletal muscle fatigue is characterized by the buildup of H+ and inorganic phosphate (Pi), metabolites that are thought to cause fatigue by inhibiting muscle force, velocity, and power. While the individual effects of elevated H+ or Pi have been well characterized, the effects of simultaneously elevating the ions, as occurs during fatigue in vivo, are still poorly understood. To address this, we exposed slow and fast rat skinned muscle fibers to fatiguing levels of H+ (pH 6.2) and Pi (30 mM)...

  11. Chronic Low-Frequency Stimulation Transforms Cat Masticatory Muscle Fibers into Jaw-Slow Fibers

    OpenAIRE

    Kang, Lucia H.D.; Hoh, Joseph F.Y.

    2011-01-01

    Cat masticatory muscle during regeneration expresses masticatory-specific myofibrillar proteins upon innervation by a fast muscle nerve but acquires the jaw-slow phenotype when innervated by a slow muscle nerve. Here, we test the hypothesis that chronic low-frequency stimulation simulating impulses from the slow nerve can result in masticatory-to-slow fiber–type transformation. In six cats, the temporalis muscle was continuously stimulated directly at 10 Hz for up to 12 weeks using a stimulat...

  12. Changes in force and stiffness during stretch of skeletal muscle fibers, effects of hypertonicity.

    OpenAIRE

    Månsson, A

    1989-01-01

    Slow stretch ramps (velocity: 0.17 fiber lengths s-1) were imposed during fused tetanic contractions of intact muscle fibers of the frog (1.4-3.0 degrees C; sarcomere length: 2.12-2.21 microns). Instantaneous force-extension relations were derived both under isometric conditions and during slow stretch by applying fast (0.2 ms) length steps to the fiber. An increase in tonicity (98 mM sucrose added to control Ringer solution) led to significant reduction of the maximum isometric tension but a...

  13. Mouse Skeletal Muscle Fiber-Type-Specific Macroautophagy and Muscle Wasting Are Regulated by a Fyn/STAT3/Vps34 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Eijiro Yamada

    2012-05-01

    Full Text Available Skeletal muscle atrophy induced by aging (sarcopenia, inactivity, and prolonged fasting states (starvation is predominantly restricted to glycolytic type II muscle fibers and typical spares oxidative type I fibers. However, the mechanisms accounting for muscle fiber-type specificity of atrophy have remained enigmatic. In the current study, although the Fyn tyrosine kinase activated the mTORC1 signaling complex, it also induced marked atrophy of glycolytic fibers with relatively less effect on oxidative muscle fibers. This was due to inhibition of macroautophagy via an mTORC1-independent but STAT3-dependent reduction in Vps34 protein levels and decreased Vps34/p150/Beclin1/Atg14 complex 1. Physiologically, in the fed state endogenous Fyn kinase activity was increased in glycolytic but not oxidative skeletal muscle. In parallel, Y705-STAT3 phosphorylation increased with decreased Vps34 protein levels. Moreover, fed/starved regulation of Y705-STAT3 phosphorylation and Vps34 protein levels was prevented in skeletal muscle of Fyn null mice. These data demonstrate a Fyn/STAT3/Vps34 pathway that is responsible for fiber-type-specific regulation of macroautophagy and skeletal muscle atrophy.

  14. Newly formed skeletal muscle fibers are prone to false positive immunostaining by rabbit antibodies

    DEFF Research Database (Denmark)

    Andersen, Ditte C; Kliem, Anette; Schrøder, Henrik Daa;

    2011-01-01

    Reports on muscle biology and regeneration often implicate immuno(cyto/histo)chemical protein characterization using rabbit polyclonal antibodies. In this study we demonstrate that newly formed myofibers are especially prone to false positive staining by rabbit antibodies and this unwanted staining...... is only recognized (1) by a negative muscle tissue control that does not harbor the protein to be examined (fx. from knockout mouse) or (2) by use of a nonsense rabbit antibody that has been prepared in the same way as the antibody of interest. However, many muscle immuno(cyto/histo)chemical studies...... only rely on controls that reveal non-specific binding by the secondary antibody and neglect that the primary rabbit antibody itself may cause false positive staining of the muscle. We suggest that reliable immuno-based protein detection in newly formed muscle fibers at least requires a nonsense rabbit...

  15. Experiment K-6-07. Metabolic and morphologic properties of muscle fibers after spaceflight

    Science.gov (United States)

    Edgerton, R.; Miu, B.; Martin, Thomas P.; Roy, R.; Marini, J.; Leger, J. J.; Oganov, V.; Ilyina-Kakueva, E.

    1990-01-01

    The present study demonstrates that the general capability of skeletal muscle to maintain its proteins decreases rapidly in response to space flight. The present findings suggest further that the magnitude of enzymatic and cell volumes changes in response to space flight depend on several factors including the muscle and its fiber type composition. It appears that in order to associate physiological relevance to the observed enzymatic changes, cell volume should be considered also. Although it remains unclear as to the stimulus, or lack of stimulus, that triggers the rapid changes in muscle proteins in response to space flight, ground-based models of muscle atrophy suggest that the reduction in mechanical loading of muscle may be more important than the total amount of activation over a 24-hr period.

  16. EUK-134 ameliorates nNOSμ translocation and skeletal muscle fiber atrophy during short-term mechanical unloading

    OpenAIRE

    Lawler, John M.; Kunst, Mary; Hord, Jeff M.; Lee, Yang; Joshi, Kumar; Botchlett, Rachel E.; Ramirez, Angelo; Martinez, Daniel A

    2014-01-01

    Reduced mechanical loading during bedrest, spaceflight, and casting, causes rapid morphological changes in skeletal muscle: fiber atrophy and reduction of slow-twitch fibers. An emerging signaling event in response to unloading is the translocation of neuronal nitric oxide synthase (nNOSμ) from the sarcolemma to the cytosol. We used EUK-134, a cell-permeable mimetic of superoxide dismutase and catalase, to test the role of redox signaling in nNOSμ translocation and muscle fiber atrophy as a r...

  17. Steady State Relation between Cytoplasmic Free Ca2+ Concentration and Force in Intact Frog Skeletal Muscle Fibers

    OpenAIRE

    Konishi, Masato; Watanabe, Masaru

    1998-01-01

    The steady state relation between cytoplasmic Ca2+ concentration ([Ca2+]i) and force was studied in intact skeletal muscle fibers of frogs. Intact twitch fibers were injected with the dextran-conjugated Ca2+ indicator, fura dextran, and the fluorescence signals of fura dextran were converted to [Ca2+]i using calibration parameters previously estimated in permeabilized muscle fibers (Konishi and Watanabe. 1995. J. Gen. Physiol. 106:1123–1150). In the first series of experiments, [Ca2+]i and is...

  18. Transduction of Skeletal Muscles with Common Reporter Genes Can Promote Muscle Fiber Degeneration and Inflammation

    OpenAIRE

    Catherine E Winbanks; Claudia Beyer; Hongwei Qian; Paul Gregorevic

    2012-01-01

    Recombinant adeno-associated viral vectors (rAAV vectors) are promising tools for delivering transgenes to skeletal muscle, in order to study the mechanisms that control the muscle phenotype, and to ameliorate diseases that perturb muscle homeostasis. Many studies have employed rAAV vectors carrying reporter genes encoding for β-galactosidase (β-gal), human placental alkaline phosphatase (hPLAP), and green fluorescent protein (GFP) as experimental controls when studying the effects of manipul...

  19. The combined influence of stretch, mobility and electrical stimulation in the prevention of muscle fiber atrophy caused hypokinesia and hypodynamia

    Science.gov (United States)

    Goldspink, G.; Goldspink, D.; Loughna, P.

    1984-01-01

    The morphological and biochemical changes which occur in the hind limb muscles of the rat in response to hypokinesia and hypodynamia were investigated. Hind limb cast fixation and suspension techniques were employed to study the musclar atrophy after five days of hypokinesia and hypodynamia induced by suspension, appreciable muscular atrophy was apparent, particularly in the anti-gravity muscles. The effect of passive stretching and electrical stimulation on muscle atrophy was studied. Changes in muscle protein mass were assessed with spectrophotometric and radioactive techniques. Passive stretch is shown to counteract muscle disuse atrophy. The change in the numbers of specific muscle fibers in atrophied muscles is discussed.

  20. Functional properties of slow and fast gastrocnemius muscle fibers after a 17-day spaceflight

    Science.gov (United States)

    Widrick, J. J.; Romatowski, J. G.; Norenberg, K. M.; Knuth, S. T.; Bain, J. L.; Riley, D. A.; Trappe, S. W.; Trappe, T. A.; Costill, D. L.; Fitts, R. H.

    2001-01-01

    The purpose of this investigation was to study the effects of a 17-day spaceflight on the contractile properties of individual fast- and slow-twitch fibers isolated from biopsies of the fast-twitch gastrocnemius muscle of four male astronauts. Single chemically skinned fibers were studied during maximal Ca2+-activated contractions with fiber myosin heavy chain (MHC) isoform expression subsequently determined by SDS gel electrophoresis. Spaceflight had no significant effect on the mean diameter or specific force of single fibers expressing type I, IIa, or IIa/IIx MHC, although a small reduction in average absolute force (P(o)) was observed for the type I fibers (0.68 +/- 0.02 vs. 0.64 +/- 0.02 mN, P fiber diameter and P(o) where significantly reduced for the type I and IIa fibers obtained from one astronaut and for the type IIa fibers from another astronaut. Average unloaded shortening velocity [V(o), in fiber lengths (FL)/s] was greater after the flight for both type I (0.60 +/- 0.03 vs. 0.76 +/- 0.02 FL/s) and IIa fibers (2.33 +/- 0.25 vs. 3.10 +/- 0.16 FL/s). Postflight peak power of the type I and IIa fibers was significantly reduced only for the astronaut experiencing the greatest fiber atrophy and loss of P(o). These results demonstrate that 1) slow and fast gastrocnemius fibers show little atrophy and loss of P(o) but increased V(o) after a typical 17-day spaceflight, 2) there is, however, considerable intersubject variation in these responses, possibly due to intersubject differences in in-flight physical activity, and 3) in these four astronauts, fiber atrophy and reductions in P(o) were less for slow and fast fibers obtained from the phasic fast-twitch gastrocnemius muscle compared with slow and fast fibers obtained from the slow antigravity soleus [J. J. Widrick, S. K. Knuth, K. M. Norenberg, J. G. Romatowski, J. L. W. Bain, D. A. Riley, M. Karhanek, S. W. Trappe, T. A. Trappe, D. L. Costill, and R. H. Fitts. J Physiol (Lond) 516: 915-930, 1999].

  1. Rat soleus muscle fiber responses to 14 days of spaceflight and hindlimb suspension

    Science.gov (United States)

    Ohira, Yoshi; Jiang, Bian; Roy, Roland R.; Oganov, V.; Il'ina-Kakueva, E. I.; Marini, J. F.; Edgerton, V. R.

    1992-01-01

    Morphological and enzymatic responses in fibers of different types were studied in rats after 14 days of spaceflight onboard Cosmos 2044 or hindlimb suspension. Fibers were classified as fast-twitch, slow-twitch, or both fast- and slow-twitch on the basis of the type of myosin heavy chains (MHC). Data obtained indicate that during the 14 days of spaceflight or suspension the protein profiles of 9-14 percents of the slow-twitch fibers reconfigured from typical slow-twitch toward fast switch fibers, while all fibers were dramatically losing total protein. These results were consistent with the data obtained from Cosmos 1887 and Skylab 3. It is suggested that effects of spaceflight on skeletal muscle can be attributed to a dramatic reduction in the level and/or pattern of loading.

  2. Changes in human muscle oxygen saturation and mean fiber conduction velocity during intense dynamic exercise - effect of muscular training status

    DEFF Research Database (Denmark)

    Kilen, Anders; Gizzi, Leonardo; Jensen, Bente Rona;

    2012-01-01

    Introduction: In this study we investigated whether an association exists between muscle fiber conduction velocity (MFCV) and local muscle oxygen saturation (StO(2) ) in the superficial part of the latissimus dorsi muscle of runners and swimmers during exhaustive dynamic exercise. Methods: Partic...

  3. Expression of Dihydropyridine and Ryanodine Receptors in Type IIA Fibers of Rat Skeletal Muscle

    International Nuclear Information System (INIS)

    In this study, the fiber type specificity of dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs) in different rat limb muscles was investigated. Western blot and histochemical analyses provided for the first time evidence that the expression of both receptors correlates to a specific myosin heavy chain (MHC) composition. We observed a significant (p=0.01) correlation between DHP as well as Ry receptor density and the expression of MHC IIa (correlation factor r=0.674 and r=0.645, respectively) in one slow-twitch, postural muscle (m. soleus), one mixed, fast-twitch muscle (m. gastrocnemius) and two fast-twitch muscles (m. rectus femoris, m. extensor digitorum longus). The highest DHP and Ry receptor density was found in the white part of m. rectus femoris (0.058±0.0060 and 0.057±0.0158 ODu, respectively). As expected, the highest relative percentage of MHC IIa was also found in the white part of m. rectus femoris (70.0±7.77%). Furthermore, histochemical experiments revealed that the IIA fibers stained most strongly for the fluorophore-conjugated receptor blockers. Our data clearly suggest that the expression of DHPRs and RyRs follows a fiber type-specific pattern, indicating an important role for these proteins in the maintenance of an effective Ca2+ cycle in the fast contracting fiber type IIA

  4. Effect of Tongue Exercise on Protrusive Force and Muscle Fiber Area in Aging Rats

    Science.gov (United States)

    Connor, Nadine P.; Russell, John A.; Wang, Hao; Jackson, Michelle A.; Mann, Laura; Kluender, Keith

    2009-01-01

    Purpose: Age-related changes in tongue function may contribute to dysphagia in elderly people. The authors' purpose was to investigate whether aged rats that have undergone tongue exercise would manifest increased protrusive tongue forces and increased genioglossus (GG) muscle fiber cross-sectional areas. Method: Forty-eight young adult,…

  5. Repeated high-intensity exercise modulates Ca(2+) sensitivity of human skeletal muscle fibers.

    Science.gov (United States)

    Gejl, K D; Hvid, L G; Willis, S J; Andersson, E; Holmberg, H-C; Jensen, R; Frandsen, U; Hansen, J; Plomgaard, P; Ørtenblad, N

    2016-05-01

    The effects of short-term high-intensity exercise on single fiber contractile function in humans are unknown. Therefore, the purposes of this study were: (a) to access the acute effects of repeated high-intensity exercise on human single muscle fiber contractile function; and (b) to examine whether contractile function was affected by alterations in the redox balance. Eleven elite cross-country skiers performed four maximal bouts of 1300 m treadmill skiing with 45 min recovery. Contractile function of chemically skinned single fibers from triceps brachii was examined before the first and following the fourth sprint with respect to Ca(2+) sensitivity and maximal Ca(2+) -activated force. To investigate the oxidative effects of exercise on single fiber contractile function, a subset of fibers was incubated with dithiothreitol (DTT) before analysis. Ca(2+) sensitivity was enhanced by exercise in both MHC I (17%, P < 0.05) and MHC II (15%, P < 0.05) fibers. This potentiation was not present after incubation of fibers with DTT. Specific force of both MHC I and MHC II fibers was unaffected by exercise. In conclusion, repeated high-intensity exercise increased Ca(2+) sensitivity in both MHC I and MHC II fibers. This effect was not observed in a reducing environment indicative of an exercise-induced oxidation of the human contractile apparatus. PMID:25944268

  6. Transduction of skeletal muscles with common reporter genes can promote muscle fiber degeneration and inflammation.

    Directory of Open Access Journals (Sweden)

    Catherine E Winbanks

    Full Text Available Recombinant adeno-associated viral vectors (rAAV vectors are promising tools for delivering transgenes to skeletal muscle, in order to study the mechanisms that control the muscle phenotype, and to ameliorate diseases that perturb muscle homeostasis. Many studies have employed rAAV vectors carrying reporter genes encoding for β-galactosidase (β-gal, human placental alkaline phosphatase (hPLAP, and green fluorescent protein (GFP as experimental controls when studying the effects of manipulating other genes. However, it is not clear to what extent these reporter genes can influence signaling and gene expression signatures in skeletal muscle, which may confound the interpretation of results obtained in experimentally manipulated muscles. Herein, we report a strong pro-inflammatory effect of expressing reporter genes in skeletal muscle. Specifically, we show that the administration of rAAV6:hPLAP vectors to the hind limb muscles of mice is associated with dose- and time-dependent macrophage recruitment, and skeletal muscle damage. Dose-dependent expression of hPLAP also led to marked activity of established pro-inflammatory IL-6/Stat3, TNFα, IKKβ and JNK signaling in lysates obtained from homogenized muscles. These effects were independent of promoter type, as expression cassettes featuring hPLAP under the control of constitutive CMV and muscle-specific CK6 promoters both drove cellular responses when matched for vector dose. Importantly, the administration of rAAV6:GFP vectors did not induce muscle damage or inflammation except at the highest doses we examined, and administration of a transgene-null vector (rAAV6:MCS did not cause damage or inflammation at any of the doses tested, demonstrating that GFP-expressing, or transgene-null vectors may be more suitable as experimental controls. The studies highlight the importance of considering the potential effects of reporter genes when designing experiments that examine gene manipulation in vivo.

  7. Solutions to muscle fiber equations and their long time behaviour

    Czech Academy of Sciences Publication Activity Database

    Krejčí, Pavel; Sainte-Marie, J.; Sorine, M.; Urquiza, J.M.

    2006-01-01

    Roč. 7, č. 4 (2006), s. 535-558. ISSN 1468-1218 Institutional research plan: CEZ:AV0Z10190503 Keywords : existence * uniqueness * muscle and cardiac mechanics Subject RIV: BA - General Mathematics Impact factor: 1.194, year: 2006 http://www.sciencedirect.com/science/article/pii/S1468121805000507

  8. Quantitative PCR Analysis of Laryngeal Muscle Fiber Types

    Science.gov (United States)

    Van Daele, Douglas J.

    2010-01-01

    Voice and swallowing dysfunction as a result of recurrent laryngeal nerve paralysis can be improved with vocal fold injections or laryngeal framework surgery. However, denervation atrophy can cause late-term clinical failure. A major determinant of skeletal muscle physiology is myosin heavy chain (MyHC) expression, and previous protein analyses…

  9. One-dimensional chain of quantum molecule motors as a mathematical physics model for muscle fibers

    Science.gov (United States)

    Si, Tie-Yan

    2015-12-01

    A quantum chain model of multiple molecule motors is proposed as a mathematical physics theory for the microscopic modeling of classical force-velocity relation and tension transients in muscle fibers. The proposed model was a quantum many-particle Hamiltonian to predict the force-velocity relation for the slow release of muscle fibers, which has not yet been empirically defined and was much more complicated than the hyperbolic relationships. Using the same Hamiltonian model, a mathematical force-velocity relationship was proposed to explain the tension observed when the muscle was stimulated with an alternative electric current. The discrepancy between input electric frequency and the muscle oscillation frequency could be explained physically by the Doppler effect in this quantum chain model. Further more, quantum physics phenomena were applied to explore the tension time course of cardiac muscle and insect flight muscle. Most of the experimental tension transient curves were found to correspond to the theoretical output of quantum two- and three-level models. Mathematical modeling electric stimulus as photons exciting a quantum three-level particle reproduced most of the tension transient curves of water bug Lethocerus maximus. Project supported by the Fundamental Research Foundation for the Central Universities of China.

  10. Chronic intrinsic transient tracheal occlusion elicits diaphragmatic muscle fiber remodeling in conscious rodents.

    Directory of Open Access Journals (Sweden)

    Barbara K Smith

    Full Text Available BACKGROUND: Although the prevalence of inspiratory muscle strength training has increased in clinical medicine, its effect on diaphragm fiber remodeling is not well-understood and no relevant animal respiratory muscle strength training-rehabilitation experimental models exist. We tested the postulate that intrinsic transient tracheal occlusion (ITTO conditioning in conscious animals would provide a novel experimental model of respiratory muscle strength training, and used significant increases in diaphragmatic fiber cross-sectional area (CSA as the primary outcome measure. We hypothesized that ITTO would increase costal diaphragm fiber CSA and further hypothesized a greater duration and magnitude of occlusions would amplify remodeling. METHODOLOGY/PRINCIPAL FINDINGS: Sprague-Dawley rats underwent surgical placement of a tracheal cuff and were randomly assigned to receive daily either 10-minute sessions of ITTO, extended-duration, 20-minute ITTO (ITTO-20, partial obstruction with 50% of cuff inflation pressure (ITTO-PAR or observation (SHAM over two weeks. After the interventions, fiber morphology, myosin heavy chain composition and CSA were examined in the crural and ventral, medial, and dorsal costal regions. In the medial costal diaphragm, with ITTO, type IIx/b fibers were 26% larger in the medial costal diaphragm (p<0.01 and 24% larger in the crural diaphragm (p<0.05. No significant changes in fiber composition or morphology were detected. ITTO-20 sessions also yielded significant increases in medial costal fiber cross-sectional area, but the effects were not greater than those elicited by 10-minute sessions. On the other hand, ITTO-PAR resulted in partial airway obstruction and did not generate fiber hypertrophy. CONCLUSIONS/SIGNIFICANCE: The results suggest that the magnitude of the load was more influential in altering fiber cross-sectional area than extended-duration conditioning sessions. The results also indicated that ITTO was

  11. Fiber-type susceptibility to eccentric contraction-induced damage of hindlimb-unloaded rat AL muscles

    Science.gov (United States)

    Vijayan, K.; Thompson, J. L.; Norenberg, K. M.; Fitts, R. H.; Riley, D. A.

    2001-01-01

    Slow oxidative (SO) fibers of the adductor longus (AL) were predominantly damaged during voluntary reloading of hindlimb unloaded (HU) rats and appeared explainable by preferential SO fiber recruitment. The present study assessed damage after eliminating the variable of voluntary recruitment by tetanically activating all fibers in situ through the motor nerve while applying eccentric (lengthening) or isometric contractions. Muscles were aldehyde fixed and resin embedded, and semithin sections were cut. Sarcomere lesions were quantified in toluidine blue-stained sections. Fibers were typed in serial sections immunostained with antifast myosin and antitotal myosin (which highlights slow fibers). Both isometric and eccentric paradigms caused fatigue. Lesions occurred only in eccentrically contracted control and HU muscles. Fatigue did not cause lesions. HU increased damage because lesioned- fiber percentages within fiber types and lesion sizes were greater than control. Fast oxidative glycolytic (FOG) fibers were predominantly damaged. In no case did damaged SO fibers predominate. Thus, when FOG, SO, and hybrid fibers are actively lengthened in chronically unloaded muscle, FOG fibers are intrinsically more susceptible to damage than SO fibers. Damaged hybrid-fiber proportions ranged between these extremes.

  12. A comparative study of aging of the elastic fiber system of the diaphragm and the rectus abdominis muscles in rats

    Directory of Open Access Journals (Sweden)

    C.J. Rodrigues

    2000-12-01

    Full Text Available In the present study the age-related changes of the striated muscle elastic fiber system were investigated in the diaphragm and rectus abdominis muscles of 1-, 4-, 8- and 18-month-old rats. The activation patterns of these muscles differ in that the diaphragm is regularly mobilized tens of times every minute during the entire life of the animal whereas the rectus abdominis, although mobilized in respiration, is much less and more irregularly activated. The elastic fibers were stained by the Verhoeff technique for mature elastic fibers. Weigert stain was used to stain mature and elaunin elastic fibers, and Weigert-oxone to stain mature, elaunin and oxytalan elastic fibers. The density of mature and elaunin elastic fibers showed a progressive increase with age, whereas the amount of oxytalan elastic fibers decreased in both diaphragm and rectus abdominis muscles and their muscular fascias. These age-related quantitative and structural changes of the elastic fiber system may reduce the viscoelastic properties of the diaphragm and rectus abdominis muscles, which may compromise the transmission of tensile muscle strength to the tendons and may affect maximum total strength.

  13. Regulation of mitochondrial respiration by inorganic phosphate; comparing permeabilized muscle fibers and isolated mitochondria prepared from type-1 and type-2 rat skeletal muscle

    DEFF Research Database (Denmark)

    Scheibye-Knudsen, Morten; Quistorff, Bjørn

    2008-01-01

    ADP is generally accepted as a key regulator of oxygen consumption both in isolated mitochondria and in permeabilized fibers from skeletal muscle. The present study explored inorganic phosphate in a similar regulatory role. Saponin permeabilized fibers and isolated mitochondria from type-I and type...

  14. Gas7-deficient mouse reveals roles in motor function and muscle fiber composition during aging.

    Directory of Open Access Journals (Sweden)

    Bo-Tsang Huang

    Full Text Available BACKGROUND: Growth arrest-specific gene 7 (Gas7 has previously been shown to be involved in neurite outgrowth in vitro; however, its actual role has yet to be determined. To investigate the physiological function of Gas7 in vivo, here we generated a Gas7-deficient mouse strain with a labile Gas7 mutant protein whose functions are similar to wild-type Gas7. METHODOLOGY/PRINCIPAL FINDINGS: Our data show that aged Gas7-deficient mice have motor activity defects due to decreases in the number of spinal motor neurons and in muscle strength, of which the latter may be caused by changes in muscle fiber composition as shown in the soleus. In cross sections of the soleus of Gas7-deficient mice, gross morphological features and levels of myosin heavy chain I (MHC I and MHC II markers revealed significantly fewer fast fibers. In addition, we found that nerve terminal sprouting, which may be associated with slow and fast muscle fiber composition, was considerably reduced at neuromuscular junctions (NMJ during aging. CONCLUSIONS/SIGNIFICANCE: These findings indicate that Gas7 is involved in motor neuron function associated with muscle strength maintenance.

  15. Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists

    DEFF Research Database (Denmark)

    Aagaard, P; Andersen, J L; Bennekou, M;

    2011-01-01

    -level endurance athletes. The present study examined the effect of 16 weeks of concurrent SE training on maximal muscle strength (MVC), contractile rate of force development (RFD), muscle fiber morphology and composition, capillarization, aerobic power (VO2max), cycling economy (CE) and long/short-term endurance......Equivocal findings exist on the effect of concurrent strength (S) and endurance (E) training on endurance performance and muscle morphology. Further, the influence of concurrent SE training on muscle fiber-type composition, vascularization and endurance capacity remains unknown in top...

  16. Effects of resistance training on endurance capacity and muscle fiber composition in young top-level cyclists

    DEFF Research Database (Denmark)

    Aagaard, P; Andersen, J L; Bennekou, M;

    2011-01-01

    -level endurance athletes. The present study examined the effect of 16 weeks of concurrent SE training on maximal muscle strength (MVC), contractile rate of force development (RFD), muscle fiber morphology and composition, capillarization, aerobic power (VO(2max) ), cycling economy (CE) and long......Equivocal findings exist on the effect of concurrent strength (S) and endurance (E) training on endurance performance and muscle morphology. Further, the influence of concurrent SE training on muscle fiber-type composition, vascularization and endurance capacity remains unknown in top...

  17. Co-expression of SERCA isoforms, phospholamban and sarcolipin in human skeletal muscle fibers.

    Directory of Open Access Journals (Sweden)

    Val A Fajardo

    Full Text Available Sarcolipin (SLN and phospholamban (PLN inhibit the activity of sarco(endoplasmic reticulum Ca(2+-ATPases (SERCAs by reducing their apparent affinity for Ca(2+. A ternary complex between SLN, PLN, and SERCAs results in super-inhibition of SERCA activity. Analysis of skeletal muscle homogenate has limited our current understanding of whether SLN and PLN regulate SERCA1a, SERCA2a, or both in skeletal muscle and whether SLN and PLN are co-expressed in skeletal muscle fibers. Biopsies from human vastus lateralis were analyzed through single fiber Western blotting and immunohisto/fluorescence staining to circumvent this limitation. With a newly generated SLN antibody, we report for the first time that SLN protein is present in human skeletal muscle. Addition of the SLN antibody (50 µg to vastus lateralis homogenates increased the apparent Ca(2+ affinity of SERCA (K Ca, pCa units (-Ab, 5.85 ± 0.02 vs. +Ab, 5.95 ± 0.02 and maximal SERCA activity (μmol/g protein/min (-Ab, 122 ± 6.4 vs. +Ab, 159 ± 11 demonstrating a functional interaction between SLN and SERCAs in human vastus lateralis. Specifically, our results suggest that although SLN and PLN may preferentially regulate SERCA1a, and SERCA2a, respectively, physiologically they both may regulate either SERCA isoform. Furthermore, we show that SLN and PLN co-immunoprecipitate in human vastus lateralis homogenate and are simultaneously expressed in 81% of the fibers analyzed with Western blotting which implies that super-inhibition of SERCA may exist in human skeletal muscle. Finally, we demonstrate unequivocally that mouse soleus contains PLN protein suggesting that super-inhibition of SERCA may also be important physiologically in rodent skeletal muscle.

  18. Muscle Fiber Characteristics, Satellite Cells and Soccer Performance in Young Athletes

    Directory of Open Access Journals (Sweden)

    Thomas I. Metaxas, Athanasios Mandroukas, Efstratios Vamvakoudis, Kostas Kotoglou, Björn Ekblom, Konstantinos Mandroukas

    2014-09-01

    Full Text Available This study is aimed to examine the muscle fiber type, composition and satellite cells in young male soccer players and to correlate them to cardiorespiratory indices and muscle strength. The participants formed three Groups: Group A (n = 13, 11.2 ± 0.4yrs, Group B (n=10, 13.1 ± 0.5yrs and Group C (n = 9, 15.2 ± 0.6yrs. Muscle biopsies were obtained from the vastus lateralis. Peak torque values of the quadriceps and hamstrings were recorded and VO2max was measured on the treadmill. Group C had lower type I percentage distribution compared to A by 21.3% (p < 0.01, while the type IIA relative percentage was higher by 18.1% and 18.4% than in Groups A and B (p < 0.05. Groups B and C had higher cross-sectional area (CSA values in all fiber types than in Group A (0.05 < p < 0.001. The number of satellite cells did not differ between the groups. Groups B and C had higher peak torque at all angular velocities and absolute VO2max in terms of ml·min-1 than Group A (0.05 < p < 0.001. It is concluded that the increased percentage of type IIA muscle fibers noticed in Group C in comparison to the Groups A and B should be mainly attributed to the different workload exercise and training programs. The alteration of myosin heavy chain (MHC isoforms composition even in children is an important mechanism for skeletal muscle characteristics. Finally, CSA, isokinetic muscle strength and VO2max values seems to be expressed according to age.

  19. Therapeutic angiogenesis in ischemic muscles after local injection of fragmented fibers with loaded traditional Chinese medicine

    Science.gov (United States)

    Li, Huiyan; Wan, Huiying; Xia, Tian; Chen, Maohua; Zhang, Yun; Luo, Xiaoming; Li, Xiaohong

    2015-07-01

    Therapeutic angiogenesis remains the most effective method to re-establish a proper blood flow in ischemic tissues. There is a great clinical need to identify an injectable format to achieve a well accumulation following local administration and a sustained delivery of biological factors at the ischemic sites. In the current study, fragmented nanofibers with loaded traditional Chinese medicines, astragaloside IV (AT), the main active ingredient of astragalus, and ferulic acid (FA), the main ingredient of angelica, were proposed to promote the microvessel formation after intramuscular injection into ischemic hindlimbs. Fragmented fibers with average lengths of 5 (FF-5), 20 (FF-20) and 80 μm (FF-80) were constructed by the cryocutting of aligned electrospun fibers. Their dispersion in sodium alginate solution (0.2%) indicated good injectability. After injection into the quadriceps muscles of the hindlimbs, FF-20 and FF-80 fiber fragments showed higher tissue retentions than FF-5, and around 90% of the injected doses were determined after 7 days. On a hindlimb ischemia model established by ligating the femoral arteries, intramuscular injection of the mixtures of FA-loaded and AT-loaded FF-20 fiber fragments substantially reduced the muscle degeneration with minimal fibrosis formation, significantly enhanced the neovessel formation and hindlimb perfusion in the ischemic tissues, and efficiently promoted the limb salvage with few limb losses. Along with the easy manipulation and lower invasiveness for in vivo administration, fragmented fibers should become potential drug carriers for disease treatment, wound recovery and tissue repair after local injection.

  20. Myosin Isoforms and Contractile Properties of Single Fibers of Human Latissimus Dorsi Muscle

    OpenAIRE

    Antonio Paoli; Pacelli, Quirico F.; Pasqua Cancellara; Luana Toniolo; Tatiana Moro; Marta Canato; Danilo Miotti; Carlo Reggiani

    2013-01-01

    The aim of our study was to investigate fiber type distribution and contractile characteristics of Latissimus Dorsi muscle (LDM). Samples were collected from 18 young healthy subjects (9 males and 9 females) through percutaneous fine needle muscle biopsy. The results showed a predominance of fast myosin heavy chain isoforms (MyHC) with 42% of MyHC 2A and 25% of MyHC 2X, while MyHC 1 represented only 33%. The unbalance toward fast isoforms was even greater in males (71%) than in females (64%...

  1. In Inclusion-Body Myositis Muscle Fibers Parkinson-Associated DJ-1 is Increased and Oxidized

    OpenAIRE

    Terracciano, Chiara; Nogalska, Anna; Engel, W. King; Wojcik, Slawomir; Askanas, Valerie

    2008-01-01

    Sporadic inclusion-body myositis (s-IBM) is the most common muscle disease of older persons. The muscle-fiber molecular phenotype exhibits similarities to both Alzheimer-disease (AD) and Parkinson-disease (PD) brains, including accumulations of amyloid-β, phosphorylated tau, α-synuclein and parkin, as well as evidence of oxidative stress and mitochondrial abnormalities. Early-onset autosomal-recessive PD can be caused by mutations in the DJ-1 gene, leading to its inactivation. DJ-1 has anti-o...

  2. MUSCLE FIBER SPECIFIC ANTIOXIDATIVE SYSTEM ADAPTATION TO SWIM TRAINING IN RATS: INFLUENCE OF INTERMITTENT HYPOXIA

    Directory of Open Access Journals (Sweden)

    Olga Gonchar

    2005-06-01

    Full Text Available The aim of the present study was to examine the influence of intermittent hypoxia at rest and in combination with long-term high-intensity swimming exercise on lipid peroxidation and antioxidant defense system adaptation in skeletal muscles differing in fiber type composition. High-intensity chronic exercise was performed as swimming training with load that corresponded to ~ 75 % VO2max (30 min·day-1, 5 days·wk-1, for 4 wk. Intermittent hypoxic training (IHT consisted of repeated episodes of hypoxia (12%O2, 15 min, interrupted by equal periods of recovery (5 sessions/day, for 2 wk. Sessions of IHT were used during the first two weeks and during the last two weeks of chronic exercise. Oxidative (red gastrocnemius and soleus, mix and glycolytic (white gastrocnemius muscles were sampled. Our results indicated that high-intensity swim training in combination with sessions of IHT induced more profound antioxidative adaptations in skeletal muscles than the exercise training only. This adaptation has muscle fiber type specificity and is reflected in significantly elevated superoxide dismutase and catalase activities in highly oxidative muscle only. Training adaptation of GSH system (reduced glutathione content, activities of glutathione reductase, glutathione peroxidase, NADPH-supplying enzyme glucose-6-phosphate dehydrogenase occurred both in slow- and fast-twitch muscles. However, this process was more effective in oxidative muscles. IHT attenuated the increase in TBARS content induced by high-intensity swimming training. The test on exercise tolerance demonstrated a significant elevation of the swimming time to exhaustion after IHT at rest and after IHT in conjunction with high-intensity exercise in comparison with untrained and chronically exercised rats. These results confirmed that sessions of IHT might improve exercise tolerance and increase maximal work capacity

  3. Effects of gamma rays on rat vascular smooth muscle fibers

    International Nuclear Information System (INIS)

    Modifications of the Vasomotoricity induced by gamma rays have been investigated. Vascular smooth muscle fibres (VSMF) of rat portal vein have been used in this study. Irradiation procedures using a 60 Co source have been carried out as follows: - Whole body irradiation. - Irradiation of isolated portal vein and isolated VSMF. Our results show that : 1-irradiation reduces the functional competition between Mg2+ and Ca2+, thus hyper magnetic Krebs solutions have a negligible effect on irradiated VSMF. 2- irradiation activates Ca2+ influx into the VSMF. Thus the effect of hypocalcemic solutions on irradiated VSMF is minor compared with control. 3- Hyperpotassic solutions provoke titanic contractions with high amplitude on the irradiated VSMF compared with control. 5 figs

  4. Fiber size, type, and myosin heavy chain content in rhesus hindlimb muscles after 2 weeks at 2 G

    Science.gov (United States)

    Tavakol, Morteza; Roy, Roland R.; Kim, Jung A.; Zhong, Hui; Hodgson, John A.; Hoban-Higgins, Tana M.; Fuller, Charles A.; Edgerton, V. Reggie

    2002-01-01

    BACKGROUND: Fiber atrophy and an increase in the percentage of fast fibers have been observed in Rhesus leg muscles after spaceflight. Hypothesis: Hypergravity will result in muscle fiber hypertrophy and an increase in the percentage of slow fibers. METHODS: Open muscle biopsies were obtained from Rhesus soleus, medial gastrocnemius (MG), and tibialis anterior (TA) muscles before and after 14 d of centrifugation (2 G) and in time-matched controls. Cage activity levels were measured by telemetry. RESULTS: Based on monoclonal antibody binding for myosin heavy chains (MHC), the fastest region of soleus contained a higher proportion of type I+II (27 vs. 13%) and had a tendency for a lower proportion of type I (38 vs. 61%, p = 0.10) fibers after than before centrifugation. There was a higher proportion of type I+II fibers in post- vs. pre-2 G (10 vs. 0.6%) MG biopsies. Fiber type distribution and MHC composition were unaffected in the TA. Overall, mean fiber sizes were unaffected by centrifugation. Average cage activity levels were 36% lower during than before 2 G. CONCLUSIONS: Our hypothesis was rejected. The changes in the proportion of fibers expressing type I MHC are the reverse of that expected with chronic loading of extensors and, paradoxically, are similar to changes observed with chronic unloading, such as occurs during spaceflight, in this primate model. The data are consistent with the observed decrease in total daily activity levels.

  5. Altered skeletal muscle fiber composition and size precede whole-body insulin resistance in young men with low birth weight

    DEFF Research Database (Denmark)

    Jensen, Christine B; Storgaard, Heidi; Madsbad, Sten;

    2007-01-01

    associated with LBW. DESIGN AND SUBJECTS: Vastus lateralis muscle was obtained by percutaneous biopsy from 20 healthy 19-yr-old men with birth weights at 10th percentile or lower for gestational age (LBW) and 20 normal birth weight controls, matched for body fat, physical fitness, and whole-body glucose......CONTEXT: Low birth weight (LBW), a surrogate marker of an adverse fetal milieu, is linked to muscle insulin resistance, impaired insulin-stimulated glycolysis, and future risk of type 2 diabetes. Skeletal muscle mass, fiber composition, and capillary density are important determinants of muscle...... disposal. Myofibrillar ATPase staining was used to classify muscle fibers as type I, IIa, and IIx (formerly type IIb), and double immunostaining was performed to stain capillaries (LBW, n=8; normal birth weight, n=12). RESULTS: LBW was associated with increased proportion of type IIx fibers (+66%; P=0...

  6. Structural design and analysis of morphing skin embedded with pneumatic muscle fibers

    International Nuclear Information System (INIS)

    In this paper, a kind of morphing skin embedded with pneumatic muscle fibers is proposed from the bionics perspective. The elastic modulus of the designed pneumatic muscle fibers is experimentally determined and their output force is tested with internal air pressure varying from 0 to 0.4 MPa. The experimental results show that the contraction ratio of the pneumatic muscle fibers using the given material could reach up to 26.8%. Isothermal tensile tests are conducted on the fabricated morphing skin, and the results are compared with theoretical predictions based on the rule of mixture. When the strain is lower than 3% and in its linear-elastic range, the rule of mixture is proved to possess satisfying accuracy in the prediction of the elastic modulus of the morphing skin. Subsequently, the output force of the morphing skin is tested. It is revealed that when the volume ratio of the pneumatic muscle fibers is 0.228, the contraction ratio can reach up to 17.8%, which is satisfactory for meeting the camber requirement of morphing skin with maximum strain level below 2%. Finally, stress-bearing capability tests of the morphing skin on local uniformly distributed loads are conducted, and the test results show that the transverse stiffness of the morphing skin can be regulated by changing the internal air pressure. Under a uniformly distributed load of 540 Pa, the designed morphing skin is capable of varying by more than two orders of magnitude in the transverse stiffness by changing the internal air pressure

  7. Human Masseter Muscle Fibers From the Elderly Express Less Neonatal Myosin Than Those of Young Adults

    Czech Academy of Sciences Publication Activity Database

    Cvetko, E.; Karen, Petr; Janáček, Jiří; Kubínová, Lucie; Plasencia, A.L.; Eržen, I.

    2012-01-01

    Roč. 295, č. 8 (2012), s. 1364-1372. ISSN 1932-8486 R&D Projects: GA MŠk(CZ) LC06063; GA MŠk(CZ) MEB090910 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : aging * confocal microscopy * myosin heavy chain * immunohistochemistry * muscle fiber types Subject RIV: FH - Neurology Impact factor: 1.343, year: 2012

  8. The influence of training status, age, and muscle fiber type on cycling efficiency and endurance performance.

    OpenAIRE

    James G. Hopker; Coleman, Damian A; Gregson, Hannah C; Simon A. Jobson; von der Haar, Tobias; Wiles, Jonathan; Passfield, Louis

    2013-01-01

    The purpose of this study was to assess the influence of age, training status, and muscle fiber-type distribution on cycling efficiency. Forty men were recruited into one of four groups: young and old trained cyclists, and young and old untrained individuals. All participants completed an incremental ramp test to measure their peak O2 uptake, maximal heart rate, and maximal minute power output; a submaximal test of cycling gross efficiency (GE) at a series of absolute and relative work rates;...

  9. An efficient framework for estimation of muscle fiber orientation using ultrasonography

    OpenAIRE

    Ling, Shan; CHEN Bin; Zhou, Yongjin; Yang, Wan-Zhang; Zhao, Yu-Qian; Wang, Lei; Zheng, Yong-Ping

    2013-01-01

    Background Muscle fiber orientation (MFO) is an important parameter related to musculoskeletal functions. The traditional manual method for MFO estimation in sonograms was labor-intensive. The automatic methods proposed in recent years also involved voting procedures which were computationally expensive. Methods In this paper, we proposed a new framework to efficiently estimate MFO in sonograms. We firstly employed Multi-scale Vessel Enhancement Filtering (MVEF) to enhance fascicles in the so...

  10. Role of Alpha-actinin-3 in Contractile Properties of Human Single Muscle Fibers: A Case Series Study in Paraplegics

    OpenAIRE

    Broos, Siacia; Malisoux, Laurent; Theisen, Daniel; Francaux, Marc; Deldicque, Louise; Thomis, Martine

    2012-01-01

    A common nonsense polymorphism in the ACTN3 gene results in the absence of α-actinin-3 in XX individuals. The wild type allele has been associated with power athlete status and an increased force output in numeral studies, though the mechanisms by which these effects occur are unclear. Recent findings in the Actn3(-/-) (KO) mouse suggest a shift towards 'slow' metabolic and contractile characteristics of fast muscle fibers lacking α-actinin-3. Skinned single fibers from the quadriceps muscle ...

  11. Muscle fiber characteristics, satellite cells and soccer performance in young athletes.

    Science.gov (United States)

    Metaxas, Thomas I; Mandroukas, Athanasios; Vamvakoudis, Efstratios; Kotoglou, Kostas; Ekblom, Björn; Mandroukas, Konstantinos

    2014-09-01

    This study is aimed to examine the muscle fiber type, composition and satellite cells in young male soccer players and to correlate them to cardiorespiratory indices and muscle strength. The participants formed three Groups: Group A (n = 13), 11.2 ± 0.4yrs, Group B (n=10), 13.1 ± 0.5yrs and Group C (n = 9), 15.2 ± 0.6yrs. Muscle biopsies were obtained from the vastus lateralis. Peak torque values of the quadriceps and hamstrings were recorded and VO2max was measured on the treadmill. Group C had lower type I percentage distribution compared to A by 21.3% (p < 0.01), while the type IIA relative percentage was higher by 18.1% and 18.4% than in Groups A and B (p < 0.05). Groups B and C had higher cross-sectional area (CSA) values in all fiber types than in Group A (0.05 < p < 0.001). The number of satellite cells did not differ between the groups. Groups B and C had higher peak torque at all angular velocities and absolute VO2max in terms of ml·min(-1) than Group A (0.05 < p < 0.001). It is concluded that the increased percentage of type IIA muscle fibers noticed in Group C in comparison to the Groups A and B should be mainly attributed to the different workload exercise and training programs. The alteration of myosin heavy chain (MHC) isoforms composition even in children is an important mechanism for skeletal muscle characteristics. Finally, CSA, isokinetic muscle strength and VO2max values seems to be expressed according to age. Key PointsFifteen years old soccer players have higher IIA percentage distribution than the younger players by approximately 18%.The age and the training status play a crucial role in muscle fibers co-expression.Specific training in young athletes seems to alter significantly the muscular metabolic profile. PMID:25177173

  12. Na+-K+-ATPase in rat skeletal muscle: muscle fiber-specific differences in exercise-induced changes in ion affinity and maximal activity

    DEFF Research Database (Denmark)

    Juel, Carsten

    2008-01-01

    It is unclear whether muscle activity reduces or increases Na(+)-K(+)-ATPase maximal in vitro activity in rat skeletal muscle, and it is not known whether muscle activity changes the Na(+)-K(+)-ATPase ion affinity. The present study uses quantification of ATP hydrolysis to characterize muscle fiber...... type-specific changes in Na(+)-K(+)-ATPase activity in sarcolemmal membranes and in total membranes obtained from control rats and after 30 min of treadmill running. ATPase activity was measured at Na(+) concentrations of 0-80 mM and K(+) concentrations of 0-10 mM. K(m) and V(max) values were obtained...

  13. Impaired regeneration of dystrophin-deficient muscle fibers is caused by exhaustion of myogenic cells

    Directory of Open Access Journals (Sweden)

    Luz M.A.M.

    2002-01-01

    Full Text Available Duchenne muscular dystrophy is one of the most devastating myopathies. Muscle fibers undergo necrosis and lose their ability to regenerate, and this may be related to increased interstitial fibrosis or the exhaustion of satellite cells. In this study, we used mdx mice, an animal model of Duchenne muscular dystrophy, to assess whether muscle fibers lose their ability to regenerate after repeated cycles of degeneration-regeneration and to establish the role of interstitial fibrosis or exhaustion of satellite cells in this process. Repeated degenerative-regenerative cycles were induced by the injection of bupivacaine (33 mg/kg, a myotoxic agent. Bupivacaine was injected weekly into the right tibialis anterior muscle of male, 8-week-old mdx (N = 20 and C57Bl/10 (control, N = 10 mice for 20 and 50 weeks. Three weeks after the last injection, the mice were killed and the proportion of regenerated fibers was counted and reported as a fibrosis index. Twenty weekly bupivacaine injections did not change the ability of mdx muscle to regenerate. However, after 50 weekly bupivacaine injections, there was a significant decrease in the regenerative response. There was no correlation between the inability to regenerate and the increase in interstitial fibrosis. These results show that after prolonged repeated cycles of degeneration-regeneration, mdx muscle loses its ability to regenerate because of the exhaustion of satellite cells, rather than because of an increase in interstitial fibrosis. This finding may be relevant to cell and gene therapy in the treatment of Duchenne muscular dystrophy.

  14. Biomineral Structure and Strength of Barnacle Exoskeletons

    Science.gov (United States)

    Swift, Nathan

    2011-03-01

    Studying the construction of organic-inorganic compound structures through biomineralization is potentially very useful. During biomineral formation, organisms restructure naturally occurring minerals in conjunction with their own organically produced minerals to create new structures. While there is extensive knowledge about material properties and structure of the raw minerals themselves, insight into how specific biomineral structures and compounds contribute to an object's mechanical properties is lacking. In this study, the exoskeletons of barnacles from the genus Balanus were examined, both for their physical structure (how they're put together) and for their mechanical properties (strength, hardness, and elasticity). Scanning electron microscopy produced close-up, detailed images of the inner shell structure to determine what type of structure barnacles build during exoskeleton formation. Energy dispersive x-ray spectroscopy was used to map the elemental components of the shells. Nanoindentation tested the mechanical properties of these mapped structures to determine how certain characteristics of the exoskeleton contribute to its mechanical properties.

  15. The miRNA Transcriptome Directly Reflects the Physiological and Biochemical Differences between Red, White, and Intermediate Muscle Fiber Types

    Directory of Open Access Journals (Sweden)

    Jideng Ma

    2015-04-01

    Full Text Available MicroRNAs (miRNAs are small non-coding RNAs that can regulate their target genes at the post-transcriptional level. Skeletal muscle comprises different fiber types that can be broadly classified as red, intermediate, and white. Recently, a set of miRNAs was found expressed in a fiber type-specific manner in red and white fiber types. However, an in-depth analysis of the miRNA transcriptome differences between all three fiber types has not been undertaken. Herein, we collected 15 porcine skeletal muscles from different anatomical locations, which were then clearly divided into red, white, and intermediate fiber type based on the ratios of myosin heavy chain isoforms. We further illustrated that three muscles, which typically represented each muscle fiber type (i.e., red: peroneal longus (PL, intermediate: psoas major muscle (PMM, white: longissimus dorsi muscle (LDM, have distinct metabolic patterns of mitochondrial and glycolytic enzyme levels. Furthermore, we constructed small RNA libraries for PL, PMM, and LDM using a deep sequencing approach. Results showed that the differentially expressed miRNAs were mainly enriched in PL and played a vital role in myogenesis and energy metabolism. Overall, this comprehensive analysis will contribute to a better understanding of the miRNA regulatory mechanism that achieves the phenotypic diversity of skeletal muscles.

  16. Quantitative evaluation of collagen fibers in country chicken muscle (Label Rouge and Pedres

    Directory of Open Access Journals (Sweden)

    Yuri Karaccas de Carvalho

    2013-03-01

    Full Text Available This study aimed to quantify collagen fibers in different lineages of country chicken at different ages and anatomical regions. The collection of material was carried out in both lineages (five poultries/treatment at two different times: 42 and 72 days of age. At each moment, a fragment of the pectoralis thoracic (PT and lateral iliotibial (LIT muscles was collected, which were fixed in 10% formaldehyde for 48 hours; they underwent a conventional histological approach, they were stained with picrosirius, and they were measured through the morphometry software KS-400 ZEISS®. The quantity of collagen fibers found in the muscles collected at 42 and 72 days, regardless of the region under study, was, respectively, 2.32±2.31% and 4.56±2.94%, for the Label Rouge lineage, and 2.26±1.61% and 4.92±2.12%, for the Pedres lineage. The quantity of collagen fibers in the different lineages and anatomical regions showed no significant statistical difference. However, when age (42 and 72 days was taken into account, a significant statistical difference was observed. The increased amount of collagen fibers found in the lineages under study is influenced by age and it’s probably one of the factors which can influence meat texture.

  17. Cytoplasm-to-myonucleus ratios and succinate dehydrogenase activities in adult rat slow and fast muscle fibers

    Science.gov (United States)

    Tseng, B. S.; Kasper, C. E.; Edgerton, V. R.

    1994-01-01

    The relationship between myonuclear number, cellular size, succinate dehydrogenase activity, and myosin type was examined in single fiber segments (n = 54; 9 +/- 3 mm long) mechanically dissected from soleus and plantaris muscles of adult rats. One end of each fiber segment was stained for DNA before quantitative photometric analysis of succinate dehydrogenase activity; the other end was double immunolabeled with fast and slow myosin heavy chain monoclonal antibodies. Mean +/- S.D. cytoplasmic volume/myonucleus ratio was higher in fast and slow plantaris fibers (112 +/- 69 vs. 34 +/- 21 x 10(3) microns3) than fast and slow soleus fibers (40 +/- 20 vs. 30 +/- 14 x 10(3) microns3), respectively. Slow fibers always had small volumes/myonucleus, regardless of fiber diameter, succinate dehydrogenase activity, or muscle of origin. In contrast, smaller diameter (fibers with high succinate dehydrogenase activity appeared to have low volumes/myonucleus while larger diameter (> 70 microns) fast fibers with low succinate dehydrogenase activity always had large volume/myonucleus. Slow soleus fibers had significantly greater numbers of myonuclei/mm than did either fast soleus or fast plantaris fibers (116 +/- 51 vs. 55 +/- 22 and 44 +/- 23), respectively. These data suggest that the myonuclear domain is more limited in slow than fast fibers and in the fibers with a high, compared to a low, oxidative metabolic capability.

  18. Microvascular oxygen pressures in muscles comprised of different fiber types: Impact of dietary nitrate supplementation.

    Science.gov (United States)

    Ferguson, Scott K; Holdsworth, Clark T; Wright, Jennifer L; Fees, Alex J; Allen, Jason D; Jones, Andrew M; Musch, Timothy I; Poole, David C

    2015-08-01

    Nitrate (NO3(-)) supplementation via beetroot juice (BR) preferentially improves vascular conductance and O2 delivery to contracting skeletal muscles comprised predominantly of type IIb + d/x (i.e. highly glycolytic) fibers following its reduction to nitrite and nitric oxide (NO). To address the mechanistic basis for NO3(-) to improve metabolic control we tested the hypothesis that BR supplementation would elevate microvascular PO2 (PO2mv) in fast twitch but not slow twitch muscle. Twelve young adult male Sprague-Dawley rats were administered BR ([NO3(-)] 1 mmol/kg/day, n = 6) or water (control, n = 6) for 5 days. PO2mv (phosphorescence quenching) was measured at rest and during 180 s of electrically-induced 1-Hz twitch contractions (6-8 V) of the soleus (9% type IIb +d/x) and mixed portion of the gastrocnemius (MG, 91% type IIb + d/x) muscles. In the MG, but not the soleus, BR elevated contracting steady state PO2mv by ~43% (control: 14 ± 1, BR: 19 ± 2 mmHg (P < 0.05)). This higher PO2mv represents a greater blood-myocyte O2 driving force during muscle contractions thus providing a potential mechanism by which NO3(-) supplementation via BR improves metabolic control in fast twitch muscle. Recruitment of higher order type II muscle fibers is thought to play a role in the development of the VO2 slow component which is inextricably linked to the fatigue process. These data therefore provide a putative mechanism for the BR-induced improvements in high-intensity exercise performance seen in humans. PMID:25280991

  19. Titin-based stiffening of muscle fibers in Ehlers-Danlos Syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Ottenheijm, Coen A.C.; Voermans, Nicol C.; Hudson, Bryan D.; Irving, Thomas; Stienen, Ger J.M.; van Engelen, Baziel G.; Granzier, Henk (IIT); (Radboud); (Ariz); (Vrije)

    2012-05-09

    Tenascin-X (TNX) is an extracellular matrix glycoprotein whose absence leads to Ehlers-Danlos Syndrome (EDS). TNX-deficient EDS patients present with joint hypermobility and muscle weakness attributable to increased compliance of the extracellular matrix. We hypothesized that in response to the increased compliance of the extracellular matrix in TNX-deficient EDS patients, intracellular adaptations take place in the elastic properties of the giant muscle protein titin. We performed extensive single muscle fiber mechanical studies to determine active and passive properties in TNX-deficient EDS patients. Gel-electrophoresis, Western blotting, and microarray studies were used to evaluate titin expression and phosphorylation. X-ray diffraction was used to measure myofilament lattice spacing. Passive tension of muscle fibers from TNX-deficient EDS patients was markedly increased. Myofilament extraction experiments indicated that the increased passive tension is attributable to changes in the properties of the sarcomeric protein titin. Transcript and protein data indicated no changes in titin isoform expression. Instead, differences in posttranslational modifications within titin's elastic region were found. In patients, active tension was not different at maximal activation level, but at submaximal activation level it was augmented attributable to increased calcium sensitivity. This increased calcium sensitivity might be attributable to stiffer titin molecules. In response to the increased compliance of the extracellular matrix in muscle of TNX-deficient EDS patients, a marked intracellular stiffening occurs of the giant protein titin. The stiffening of titin partly compensates for the muscle weakness in these patients by augmenting submaximal active tension generation.

  20. Effect of fiber type and nutritional state on AICAR- and contraction-stimulated glucose transport in rat muscle

    DEFF Research Database (Denmark)

    Ai, Hua; Ihlemann, Jacob; Hellsten, Ylva;

    2002-01-01

    AMP-activated protein kinase (AMPK) may mediate the stimulatory effect of contraction and 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on glucose transport in skeletal muscle. In muscles with different fiber type composition from fasted rats, AICAR increased 2-deoxyglucose transport and ...

  1. Coupled expression of troponin T and troponin I isoforms in single skeletal muscle fibers correlates with contractility

    OpenAIRE

    Brotto, Marco A.; Biesiadecki, Brandon J.; Brotto, Leticia S.; Nosek, Thomas M.; Jin, J.-P.

    2005-01-01

    Brotto, Marco A., Brandon J. Biesiadecki, Leticia S. Brotto, Thomas M. Nosek, and J.-P. Jin. Striated muscle contraction is powered by actin-activated myosin ATPase. This process is regulated by Ca2+ via the troponin complex. Slow and fast twitch fibers of vertebrate skeletal muscle express type I and type II myosin, respectively, and these myosin isoenzymes confer different ATPase activities, contractile velocities and force. Skeletal muscle troponin has also diverged into fast and slow isof...

  2. Protein Supplementation Does Not Further Increase Latissimus Dorsi Muscle Fiber Hypertrophy after Eight Weeks of Resistance Training in Novice Subjects, but Partially Counteracts the Fast-to-Slow Muscle Fiber Transition

    Science.gov (United States)

    Paoli, Antonio; Pacelli, Quirico F.; Cancellara, Pasqua; Toniolo, Luana; Moro, Tatiana; Canato, Marta; Miotti, Danilo; Neri, Marco; Morra, Aldo; Quadrelli, Marco; Reggiani, Carlo

    2016-01-01

    The response to resistance training and protein supplementation in the latissimus dorsi muscle (LDM) has never been investigated. We investigated the effects of resistance training (RT) and protein supplementation on muscle mass, strength, and fiber characteristics of the LDM. Eighteen healthy young subjects were randomly assigned to a progressive eight-week RT program with a normal protein diet (NP) or high protein diet (HP) (NP 0.85 vs. HP 1.8 g of protein·kg−1·day−1). One repetition maximum tests, magnetic resonance imaging for cross-sectional muscle area (CSA), body composition, and single muscle fibers mechanical and phenotype characteristics were measured. RT induced a significant gain in strength (+17%, p protein supplementation showed no significant effects on all measured outcomes except for a smaller reduction of 2X myosin expression. Our results suggest that in LDM protein supplementation does not further enhance RT-induced muscle fiber hypertrophy nor influence mechanic muscle fiber characteristics but partially counteracts the fast-to-slow fiber shift. PMID:27258300

  3. Pre-embedding staining of single muscle fibers for light and electron microscopy studies of subcellular organization

    DEFF Research Database (Denmark)

    Ralston, E; Ploug, Thorkil

    1996-01-01

    ) immunocytochemistry. Here we show that pre-embedding staining of single teased fibers, or of single enzymatically dissociated fibers, has several advantages over the use of sections for observing discrete patterns that extend over long distances in the cells. We report on an optimization study carried out to......Skeletal muscle fibers are large, multinucleated cells which pose a challenge to the morphologist. In the course of studies of the distribution of the glucose transporter GLUT4, in muscle, we have compared different preparative procedures, for both light (LM) and electron microscopy (EM...

  4. NFATc1 Controls Skeletal Muscle Fiber Type and Is a Negative Regulator of MyoD Activity

    Directory of Open Access Journals (Sweden)

    Melissa L. Ehlers

    2014-09-01

    Full Text Available Skeletal muscle comprises a heterogeneous population of fibers with important physiological differences. Fast fibers are glycolytic and fatigue rapidly. Slow fibers utilize oxidative metabolism and are fatigue resistant. Muscle diseases such as sarcopenia and atrophy selectively affect fast fibers, but the molecular mechanisms regulating fiber type-specific gene expression remain incompletely understood. Here, we show that the transcription factor NFATc1 controls fiber type composition and is required for fast-to-slow fiber type switching in response to exercise in vivo. Moreover, MyoD is a crucial transcriptional effector of the fast fiber phenotype, and we show that NFATc1 inhibits MyoD-dependent fast fiber gene promoters by physically interacting with the N-terminal activation domain of MyoD and blocking recruitment of the essential transcriptional coactivator p300. These studies establish a molecular mechanism for fiber type switching through direct inhibition of MyoD to control the opposing roles of MyoD and NFATc1 in fast versus slow fiber phenotypes.

  5. Fluorescent modification and orientation of myosin sulfhydryl 2 in skeletal muscle fibers

    International Nuclear Information System (INIS)

    The authors describe a protocol for the selective covalent labeling of the sulfhydryl 2 (SH2) on the myosin cross-bridge in glycerinated muscle fibers using the sulfhydryl-selective label 4-[N-[(iodoacetoxy)ethyl]-N-methylamino]-7-nitrobenz-2-oxa-1,3-diazole (IANBD). The protocol promotes the specificity of IANBD by using the ability to protect sulfhydryl 1 (SH1) from modification by binding the cross-bridge to the actin filament and using cross-bridge-bound MgADP to promote the accessibility of SH2. They determined the specificity of the probe using fluorescence gel scanning of fiber-extracted proteins to isolate the probe on myosin subfragment 1 (S1), limited proteolysis of the purified S1 to isolate the probe on the 20-kilodalton fragment of S1, and titration of the free SH1's on purified S1 using the radiolabeled SH1-specific reagent [14C]iodoacetamide or enzymatic activity measurements. They characterized the angular distribution of the IANBD on cross-bridges in fibers when the fibers are in rigor, in relaxation, in the presence of MgADP, and in isometric contraction using wavelength-dependent fluorescence polarization. They find that the SH2 probe distinguishes the different states of the fiber such that rigor and MgADP are ordered and maintain a similar orientation throughout the excitation wavelength domain. The relaxed cross-bridge is ordered and has an orientation that is distinct from the orientation of the cross-bridge in rigor and MgADP over the entire wavelength domain. The active isometric cross-bridge is also oriented differently from the other states, suggesting the presence of a predominant actin-bound cross-bridge state that precedes the power stroke during muscle contraction

  6. Antennular specialization in cyprids of coral associated barnacles

    DEFF Research Database (Denmark)

    Brinckner, I.; Høeg, Jens Thorvald

    2010-01-01

    We used video, light and scanning electron microscopy to study the cypris larvae in species of coral inhabiting barnacles (Pyrgomatidae) in search of adaptations to settlement on their highly unusual substratum. Species studied were Savignium crenatum, Trevathana jensi, Trevathana margaretae...... barnacles that use the antennule for active penetration of cuticles. Compared to the third segment, the ¿rst, second and fourth segments exhibit no obvious specializations, and the armament of sensory setae is also as very comparable to that seen in balanomorphan cirripedes. The coral barnacles also have...... the nauplius eye, compound eyes, frontal ¿laments, lattice organs and cement glands known from other barnacles. Only T. sarae differed by having two unusually shaped setae terminally on the fourth segment. Video observations showed that the coral barnacle cyprids display the exploratory walking...

  7. Transgenic mice expressing mutant Pinin exhibit muscular dystrophy, nebulin deficiency and elevated expression of slow-type muscle fiber genes

    International Nuclear Information System (INIS)

    Highlights: •Pnn CCD domain functions as a dominant negative mutant regulating Pnn expression and function. •Pnn CCD mutant Tg mice have a muscle wasting phenotype during development and show dystrophic histological features. •Pnn mutant muscles are susceptible to slow fiber type gene transition and NEB reduction. •The Tg mouse generated by overexpression of the Pnn CCD domain displays many characteristics resembling NEB+/− mice. -- Abstract: Pinin (Pnn) is a nuclear speckle-associated SR-like protein. The N-terminal region of the Pnn protein sequence is highly conserved from mammals to insects, but the C-terminal RS domain-containing region is absent in lower species. The N-terminal coiled-coil domain (CCD) is, therefore, of interest not only from a functional point of view, but also from an evolutionarily standpoint. To explore the biological role of the Pnn CCD in a physiological context, we generated transgenic mice overexpressing Pnn mutant in skeletal muscle. We found that overexpression of the CCD reduces endogenous Pnn expression in cultured cell lines as well as in transgenic skeletal muscle fibers. Pnn mutant mice exhibited reduced body mass and impaired muscle function during development. Mutant skeletal muscles show dystrophic histological features with muscle fibers heavily loaded with centrally located myonuclei. Expression profiling and pathway analysis identified over-representation of genes in gene categories associated with muscle contraction, specifically those related to slow type fiber. In addition nebulin (NEB) expression level is repressed in Pnn mutant skeletal muscle. We conclude that Pnn downregulation in skeletal muscle causes a muscular dystrophic phenotype associated with NEB deficiency and the CCD domain is incapable of replacing full length Pnn in terms of functional capacity

  8. Transgenic mice expressing mutant Pinin exhibit muscular dystrophy, nebulin deficiency and elevated expression of slow-type muscle fiber genes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Hsu-Pin; Hsu, Shu-Yuan [Department of Anatomy, Chang Gung University Medical College, Taiwan (China); Wu, Wen-Ai; Hu, Ji-Wei [Transgenic Mouse Core Laboratory, Chang Gung University, Taiwan (China); Ouyang, Pin, E-mail: ouyang@mail.cgu.edu.tw [Department of Anatomy, Chang Gung University Medical College, Taiwan (China); Transgenic Mouse Core Laboratory, Chang Gung University, Taiwan (China); Molecular Medicine Research Center, Chang Gung University, Taiwan (China)

    2014-01-03

    Highlights: •Pnn CCD domain functions as a dominant negative mutant regulating Pnn expression and function. •Pnn CCD mutant Tg mice have a muscle wasting phenotype during development and show dystrophic histological features. •Pnn mutant muscles are susceptible to slow fiber type gene transition and NEB reduction. •The Tg mouse generated by overexpression of the Pnn CCD domain displays many characteristics resembling NEB{sup +/−} mice. -- Abstract: Pinin (Pnn) is a nuclear speckle-associated SR-like protein. The N-terminal region of the Pnn protein sequence is highly conserved from mammals to insects, but the C-terminal RS domain-containing region is absent in lower species. The N-terminal coiled-coil domain (CCD) is, therefore, of interest not only from a functional point of view, but also from an evolutionarily standpoint. To explore the biological role of the Pnn CCD in a physiological context, we generated transgenic mice overexpressing Pnn mutant in skeletal muscle. We found that overexpression of the CCD reduces endogenous Pnn expression in cultured cell lines as well as in transgenic skeletal muscle fibers. Pnn mutant mice exhibited reduced body mass and impaired muscle function during development. Mutant skeletal muscles show dystrophic histological features with muscle fibers heavily loaded with centrally located myonuclei. Expression profiling and pathway analysis identified over-representation of genes in gene categories associated with muscle contraction, specifically those related to slow type fiber. In addition nebulin (NEB) expression level is repressed in Pnn mutant skeletal muscle. We conclude that Pnn downregulation in skeletal muscle causes a muscular dystrophic phenotype associated with NEB deficiency and the CCD domain is incapable of replacing full length Pnn in terms of functional capacity.

  9. Role of alpha-actinin-3 in contractile properties of human single muscle fibers: a case series study in paraplegics.

    Directory of Open Access Journals (Sweden)

    Siacia Broos

    Full Text Available A common nonsense polymorphism in the ACTN3 gene results in the absence of α-actinin-3 in XX individuals. The wild type allele has been associated with power athlete status and an increased force output in numeral studies, though the mechanisms by which these effects occur are unclear. Recent findings in the Actn3(-/- (KO mouse suggest a shift towards 'slow' metabolic and contractile characteristics of fast muscle fibers lacking α-actinin-3. Skinned single fibers from the quadriceps muscle of three men with spinal cord injury (SCI were tested regarding peak force, unloaded shortening velocity, force-velocity relationship, passive tension and calcium sensitivity. The SCI condition induces an 'equal environment condition' what makes these subjects ideal to study the role of α-actinin-3 on fiber type expression and single muscle fiber contractile properties. Genotyping for ACTN3 revealed that the three subjects were XX, RX and RR carriers, respectively. The XX carrier's biopsy was the only one that presented type I fibers with a complete lack of type II(x fibers. Properties of hybrid type II(a/II(x fibers were compared between the three subjects. Absence of α-actinin-3 resulted in less stiff type II(a/II(x fibers. The heterozygote (RX exhibited the highest fiber diameter (0.121±0.005 mm and CSA (0.012±0.001 mm(2 and, as a consequence, the highest peak force (2.11±0.14 mN. Normalized peak force was similar in all three subjects (P = 0.75. Unloaded shortening velocity was highest in R-allele carriers (P<0.001. No difference was found in calcium sensitivity. The preservation of type I fibers and the absence of type II(x fibers in the XX individual indicate a restricted transformation of the muscle fiber composition to type II fibers in response to long-term muscle disuse. Lack of α-actinin-3 may decrease unloaded shortening velocity and increase fiber elasticity.

  10. Sonic hedgehog enhances somite cell viability and formation of primary slow muscle fibers in avian segmented mesoderm.

    Science.gov (United States)

    Cann, G M; Lee, J W; Stockdale, F E

    1999-09-01

    Primary skeletal muscle fibers first form in the segmented portions of paraxial mesoderm called somites. Although the neural tube and notochord are recognized as crucial in patterning myogenic cell lineages during avian and mammalian somitic myogenesis, the source, identities, and actions of the signals governing this process remain controversial. It has been shown that signals emanating from the ventral neural tube and/or notochord alone or Shh alone serve to activate MyoD expression in somites. However, beyond a role in initiating MyoD expression, little is known about the effects of Shh on primary muscle fiber formation in somites of higher vertebrates. The studies reported here investigate how the ventral neural tube promotes myogenesis and compare the effects of the ventral neural tube with those of purified Shh protein on fiber formation in somites. We show that purified Shh protein mimics actions of the ventral neural tube on somites including initiation of muscle fiber formation, enhancement of numbers of primary muscle fibers, and particularly, the formation of primary fibers that express slow myosin. There is a marked increase in slow myosin expression in fibers in response to Shh as somites mature. The effects of ventral neural tube on fiber formation can be blocked by disrupting the Shh signaling pathway by increasing the activity of somitic cyclic AMP-dependent protein kinase A. Furthermore, it was demonstrated that apoptosis is a dominant fate of somite cells, but not somitic muscle fibers, when cultured in the absence of the neural tube, and that application of Shh protein to somites reduced apoptosis. The block to apoptosis by Shh is a manifestation of the maturity of the somite with a progressive increase in the block as somites are displaced rostrally from somite III forward. We conclude that purified Shh protein in mimicking the effects of the ventral neural tube on segmented mesoderm can exert pleiotropic effects during primary myogenesis

  11. MUSCLE FIBER SPECIFIC ANTIOXIDATIVE SYSTEM ADAPTATION TO SWIM TRAINING IN RATS: INFLUENCE OF INTERMITTENT HYPOXIA

    OpenAIRE

    Olga Gonchar

    2005-01-01

    The aim of the present study was to examine the influence of intermittent hypoxia at rest and in combination with long-term high-intensity swimming exercise on lipid peroxidation and antioxidant defense system adaptation in skeletal muscles differing in fiber type composition. High-intensity chronic exercise was performed as swimming training with load that corresponded to ~ 75 % VO2max (30 min·day-1, 5 days·wk-1, for 4 wk). Intermittent hypoxic training (IHT) consisted of repeated episodes o...

  12. Skeletal muscle fiber type composition and performance during repeated bouts of maximal, concentric contractions

    Science.gov (United States)

    Colliander, E. B.; Dudley, G. A.; Tesch, P. A.

    1988-01-01

    Force output and fatigue and recovery patterns were studied during intermittent short-term exercise. 27 men performed three bouts of 30 maximal unilateral knee extensions on 2 different occasions. Blood flow was maintained or occluded during recovery periods (60 s). Blood flow was restricted by inflating a pneumatic cuff placed around the proximal thigh. Muscle biopsies from vastus lateralis were analyzed for identification of fast twitch (FT) and slow twitch (ST) fibers and relative FT area. Peak torque decreased during each bout of exercise and more when blood flow was restricted during recovery. Initial peak torque (IPT) and average peak torque (APT) decreased over the three exercise bouts. This response was 3 fold greater without than with blood flow during recovery. IPT and APT decreased more in individuals with mainly FT fibers than in those with mainly ST fibers. It is suggested that performance during repeated bouts of maximal concentric contractions differs between individuals with different fiber type composition. Specifically, in high intensity, intermittent exercise with emphasis on anaerobic energy release a high FT composition may not necessarily be advantageous for performance.

  13. Action potential-evoked calcium release is impaired in single skeletal muscle fibers from heart failure patients.

    Directory of Open Access Journals (Sweden)

    Marino DiFranco

    Full Text Available BACKGROUND: Exercise intolerance in chronic heart failure (HF has been attributed to abnormalities of the skeletal muscles. Muscle function depends on intact excitation-contraction coupling (ECC, but ECC studies in HF models have been inconclusive, due to deficiencies in the animal models and tools used to measure calcium (Ca2+ release, mandating investigations in skeletal muscle from HF patients. The purpose of this study was to test the hypothesis that Ca2+ release is significantly impaired in the skeletal muscle of HF patients in whom exercise capacity is severely diminished compared to age-matched healthy volunteers. METHODS AND FINDINGS: Using state-of-the-art electrophysiological and optical techniques in single muscle fibers from biopsies of the locomotive vastus lateralis muscle, we measured the action potential (AP-evoked Ca2+ release in 4 HF patients and 4 age-matched healthy controls. The mean peak Ca2+ release flux in fibers obtained from HF patients (10±1.2 µM/ms was markedly (2.6-fold and significantly (p<0.05 smaller than in fibers from healthy volunteers (28±3.3 µM/ms. This impairment in AP-evoked Ca2+ release was ubiquitous and was not explained by differences in the excitability mechanisms since single APs were indistinguishable between HF patients and healthy volunteers. CONCLUSIONS: These findings prove the feasibility of performing electrophysiological experiments in single fibers from human skeletal muscle, and offer a new approach for investigations of myopathies due to HF and other diseases. Importantly, we have demonstrated that one step in the ECC process, AP-evoked Ca2+ release, is impaired in single muscle fibers in HF patients.

  14. Barnacles and their significance in biofouling

    Digital Repository Service at National Institute of Oceanography (India)

    Anil, A.C.; Desai, D.V.; Khandeparker, L.; Gaonkar, C.A.

    from the floating object. The stalk of gooseneck barnacles is simply an elongation of the attached end of the animal's body. They are filter feeders using their legs to filter plankton, which then pass them to their mouth. The capitulum is ventral..., often protected by calcarious plates and is held away from the substratum by the peduncle (Fig.1a). It is roughly oblong with five smooth white plates, separated by red/brown or black tissue. The capitulum consists of most of the animal, including...

  15. The tempo and mode of barnacle evolution

    DEFF Research Database (Denmark)

    Pérez-Losada, Marcos; Harp, Margaret; Høeg, Jens T; Achituv, Yair; Jones, Diana; Watanabe, Hiromi; Crandall, Keith A

    2008-01-01

    (outgroup) species representing almost all the Thoracica families to assess the tempo and mode of barnacle evolution. Using phylogenetic methods of maximum parsimony, maximum likelihood, and Bayesian inference and 14 fossil calibrations, we found that: (1) Iblomorpha form a monophyletic group; (2...... are each monophyletic and together they form a monophyletic group; (5) asymmetry and loss of a peduncle have evolved twice in the Thoracica, resulting in neither the Verrucomorpha nor the Sessilia forming monophyletic groups in their present definitions; (6) the Scalpellomorpha are not monophyletic...

  16. Calcium-binding properties of troponin C in detergent-skinned heart muscle fibers

    International Nuclear Information System (INIS)

    In order to obtain information with regard to behavior of the Ca2+ receptor, troponin C (TnC), in intact myofilament lattice of cardiac muscle, we investigated Ca2+-binding properties of canine ventricular muscle fibers skinned with Triton X-100. Analysis of equilibrium Ca2+-binding data of the skinned fibers in ATP-free solutions suggested that there were two distinct classes of binding sites which were saturated over the physiological range of negative logarithm of free calcium concentration (pCa): class I (KCa = 7.4 X 10(7) M-1, KMg = 0.9 X 10(3) M-1) and class II (KCa = 1.2 X 10(6) M-1, KMg = 1.1 X 10(2) M-1). The class I and II were considered equivalent, respectively, to the Ca2+-Mg2+ and Ca2+-specific sites of TnC. The assignments were supported by TnC content of the skinned fibers determined by electrophoresis and 45Ca autoradiograph of electroblotted fiber proteins. Dissociation of rigor complexes by ATP caused a downward shift of the binding curve between pCa 7 and 5, an effect which could be largely accounted for by lowering of KCa of the class II sites. When Ca2+ binding and isometric force were measured simultaneously, it was found that the threshold pCa for activation corresponds to the range of pCa where class II sites started to bind Ca2+ significantly. We concluded that the low affinity site of cardiac TnC plays a key role in Ca2+ regulation of contraction under physiological conditions, just as it does in the regulation of actomyosin ATPase. Study of kinetics of 45Ca washout from skinned fibers and myofibrils revealed that cardiac TnC in myofibrils contains Ca2+-binding sites whose off-rate constant for Ca2+ is significantly lower than the Ca2+ off-rate constant hitherto documented for the divalent ion-binding sites of either cardiac/slow muscle TnC or fast skeletal TnC

  17. Functional pools of oxidative and glycolytic fibers in human muscle observed by 31P magnetic resonance spectroscopy during exercise

    International Nuclear Information System (INIS)

    Quantitative probing of heterogeneous regions in muscle is feasible with phosphorus-31 magnetic resonance spectroscopy because of the differentiation of metabolic patterns of glycolytic and oxidative fibers. A differential recruitment of oxidative and glycolytic fibers during exercise was demonstrated in 4 of 10 untrained young men by following changes in phosphate metabolites. Concentrations of inorganic phosphate (P/sub i/), phosphocreatine, and ATP were estimated in the wrist flexor muscles of the forearm at rest, during two cycles of three grades of exercise, and in recovery. At high work levels (40% of maximum strength), two distinct P/sub i/ peaks were observed and identified with P/sub i/ pools at pH 6.9 and pH 5.9-6.4, respectively. These could be accounted for as follows. At the lowest level of work (using 20% of maximum strength), early recruitment primarily of oxidative (type I) and possibly some intermediate (type IIA) muscle fibers occurs with relatively little net lactate production and consequently little decrease in pH. At higher work loads, however, primarily glycolytic (type IIB) muscle fibers are recruited, which have relatively high net lactate production and therefore generate a second pool of P/sub i/ at low pH. These observations indicated exhaustion of glycolytic type IIB fibers, removal of lactate by high local blood flow, and sustained contractions largely by oxidative type I and IIA fibers. A functional differentiation of fiber types could also be demonstrated during recovery if exercise was stopped while two pools of P/sub i/ were still apparent. The potential of magnetic resonance spectroscopy to characterize oxidative and glycolytic fibers, predict capacity for aerobic performance, and signal the presence of muscle pathology is discussed

  18. Role(s) of gravitational loading during developing period on the growth of rat soleus muscle fibers.

    Science.gov (United States)

    Kawano, Fuminori; Goto, Katsumasa; Wang, Xiao Dong; Terada, Masahiro; Ohira, Takashi; Nakai, Naoya; Yoshioka, Toshitada; Ohira, Yoshinobu

    2010-03-01

    Effects of gravitational loading or unloading on the gain of the characteristics in soleus muscle fibers were studied in rats. The tail suspension was performed in newborn rats from postnatal day 4 to month 3, and the reloading was allowed for 3 mo in some rats. Single expression of type I myosin heavy chain (MHC) was observed in approximately 82% of fibers in 3-mo-old controls, but the fibers expressing multiple MHC isoforms were noted in the unloaded rats. Although 97% of fibers in 3-mo-old controls had a single neuromuscular junction at the central region of fiber, fibers with multiple nerve endplates were seen in the unloaded group. Faster contraction speed and lower maximal tension development, even after normalization with fiber size, were observed in the unloaded pure type I MHC fibers. These parameters generally returned to the age-matched control levels after reloading. It was suggested that antigravity-related tonic activity plays an important role in the gain of single neural innervation and of slow contractile properties and phenotype in soleus muscle fibers. PMID:20056853

  19. Impaired Organization and Function of Myofilaments in Single Muscle Fibers from a Mouse Model of Pompe Disease

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.; Galperin, M; Melvin, G; Horowits, R; Raben, N; Plotz, P; Yu, L

    2010-01-01

    Pompe disease, a deficiency of lysosomal acid {alpha}-glucosidase, is a disorder of glycogen metabolism that can affect infants, children, or adults. In all forms of the disease, there is progressive muscle pathology leading to premature death. The pathology is characterized by accumulation of glycogen in lysosomes, autophagic buildup, and muscle atrophy. The purpose of the present investigation was to determine if myofibrillar dysfunction in Pompe disease contributes to muscle weakness beyond that attributed to atrophy. The study was performed on isolated myofibers dissected from severely affected fast glycolytic muscle in the {alpha}-glucosidase knockout mouse model. Psoas muscle fibers were first permeabilized, so that the contractile proteins could be directly relaxed or activated by control of the composition of the bathing solution. When normalized by cross-sectional area, single fibers from knockout mice produced 6.3 N/cm{sup 2} of maximum Ca{sup 2+}-activated tension compared with 12.0 N/cm{sup 2} produced by wild-type fibers. The total protein concentration was slightly higher in the knockout mice, but concentrations of the contractile proteins myosin and actin remained unchanged. Structurally, X-ray diffraction showed that the actin and myosin filaments, normally arranged in hexagonal arrays, were disordered in the knockout muscle, and a lower fraction of myosin cross bridges was near the actin filaments in the relaxed muscle. The results are consistent with a disruption of actin and myosin interactions in the knockout muscles, demonstrating that impaired myofibrillar function contributes to weakness in the diseased muscle fibers.

  20. Dynamics of tropomyosin in muscle fibers as monitored by saturation transfer EPR of bi-functional probe.

    Directory of Open Access Journals (Sweden)

    Roni F Rayes

    Full Text Available The dynamics of four regions of tropomyosin was assessed using saturation transfer electron paramagnetic resonance in the muscle fiber. In order to fully immobilize the spin probe on the surface of tropomyosin, a bi-functional spin label was attached to i,i+4 positions via cysteine mutagenesis. The dynamics of bi-functionally labeled tropomyosin mutants decreased by three orders of magnitude when reconstituted into "ghost muscle fibers". The rates of motion varied along the length of tropomyosin with the C-terminus position 268/272 being one order of magnitude slower then N-terminal domain or the center of the molecule. Introduction of troponin decreases the dynamics of all four sites in the muscle fiber, but there was no significant effect upon addition of calcium or myosin subfragment-1.

  1. Skeletal muscle myostatin mRNA expression is fiber-type specific and increases during hindlimb unloading

    Science.gov (United States)

    Carlson, C. J.; Booth, F. W.; Gordon, S. E.

    1999-01-01

    Transgenic mice lacking a functional myostatin (MSTN) gene demonstrate greater skeletal muscle mass resulting from muscle fiber hypertrophy and hyperplasia (McPherron, A. C., A. M. Lawler, and S. -J. Lee. Nature 387: 83-90, 1997). Therefore, we hypothesized that, in normal mice, MSTN may act as a negative regulator of muscle mass. Specifically, we hypothesized that the predominately slow (type I) soleus muscle, which demonstrates greater atrophy than the fast (type II) gastrocnemius-plantaris complex (Gast/PLT), would show more elevation in MSTN mRNA abundance during hindlimb unloading (HU). Surprisingly, MSTN mRNA was not detectable in weight-bearing or HU soleus muscle, which atrophied 42% by the 7th day of HU in female ICR mice. In contrast, MSTN mRNA was present in weight-bearing Gast/PLT muscle and was significantly elevated (67%) at 1 day but not at 3 or 7 days of HU. However, the Gast/PLT muscle had only atrophied 17% by the 7th day of HU. Because the soleus is composed only of type I and IIa fibers, whereas the Gast/PLT expresses type IId/x and IIb in addition to type I and IIa, it was necessary to perform a more careful analysis of the relationship between MSTN mRNA levels and myosin heavy-chain (MHC) isoform expression (as a marker of fiber type). A significant correlation (r = 0.725, P muscles of the mouse hindlimb. These results indicate that MSTN expression is not strongly associated with muscle atrophy induced by HU; however, it is strongly associated with MHC isoform IIb expression in normal muscle.

  2. Laser ablation of Drosophila embryonic motoneurons causes ectopic innervation of target muscle fibers

    Science.gov (United States)

    Chang, T. N.; Keshishian, H.

    1996-01-01

    We have tested the effects of neuromuscular denervation in Drosophila by laser-ablating the RP motoneurons in intact embryos before synaptogenesis. We examined the consequences of this ablation on local synaptic connectivity in both 1st and 3rd instar larvae. We find that the partial or complete loss of native innervation correlates with the appearance of alternate inputs from neighboring motor endings and axons. These collateral inputs are found at ectopic sites on the denervated target muscle fibers. The foreign motor endings are electrophysiologically functional and are observed on the denervated muscle fibers by the 1st instar larval stage. Our data are consistent with the existence of a local signal from the target environment, which is regulated by innervation and influences synaptic connectivity. Our results show that, despite the stereotypy of Drosophila neuromuscular connections, denervation can induce local changes in connectivity in wild-type Drosophila, suggesting that mechanisms of synaptic plasticity may also be involved in normal Drosophila neuromuscular development.

  3. Effect of spaceflight on the isotonic contractile properties of single skeletal muscle fibers in the rhesus monkey

    Science.gov (United States)

    Fitts, R. H.; Romatowski, J. G.; Blaser, C.; De La Cruz, L.; Gettelman, G. J.; Widrick, J. J.

    2000-01-01

    Experiments from both Cosmos and Space Shuttle missions have shown weightlessness to result in a rapid decline in the mass and force of rat hindlimb extensor muscles. Additionally, despite an increased maximal shortening velocity, peak power was reduced in rat soleus muscle post-flight. In humans, declines in voluntary peak isometric ankle extensor torque ranging from 15-40% have been reported following long- and short-term spaceflight and prolonged bed rest. Complete understanding of the cellular events responsible for the fiber atrophy and the decline in force, as well as the development of effective countermeasures, will require detailed knowledge of how the physiological and biochemical processes of muscle function are altered by spaceflight. The specific purpose of this investigation was to determine the extent to which the isotonic contractile properties of the slow- and fast-twitch fiber types of the soleus and gastrocnemius muscles of rhesus monkeys (Macaca mulatta) were altered by a 14-day spaceflight.

  4. Fiber type conversion by PGC-1α activates lysosomal and autophagosomal biogenesis in both unaffected and Pompe skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Shoichi Takikita

    Full Text Available PGC-1α is a transcriptional co-activator that plays a central role in the regulation of energy metabolism. Our interest in this protein was driven by its ability to promote muscle remodeling. Conversion from fast glycolytic to slow oxidative fibers seemed a promising therapeutic approach in Pompe disease, a severe myopathy caused by deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA which is responsible for the degradation of glycogen. The recently approved enzyme replacement therapy (ERT has only a partial effect in skeletal muscle. In our Pompe mouse model (KO, the poor muscle response is seen in fast but not in slow muscle and is associated with massive accumulation of autophagic debris and ineffective autophagy. In an attempt to turn the therapy-resistant fibers into fibers amenable to therapy, we made transgenic KO mice expressing PGC-1α in muscle (tgKO. The successful switch from fast to slow fibers prevented the formation of autophagic buildup in the converted fibers, but PGC-1α failed to improve the clearance of glycogen by ERT. This outcome is likely explained by an unexpected dramatic increase in muscle glycogen load to levels much closer to those observed in patients, in particular infants, with the disease. We have also found a remarkable rise in the number of lysosomes and autophagosomes in the tgKO compared to the KO. These data point to the role of PGC-1α in muscle glucose metabolism and its possible role as a master regulator for organelle biogenesis - not only for mitochondria but also for lysosomes and autophagosomes. These findings may have implications for therapy of lysosomal diseases and other disorders with altered autophagy.

  5. Gut microbiota can transfer fiber characteristics and lipid metabolic profiles of skeletal muscle from pigs to germ-free mice.

    Science.gov (United States)

    Yan, Honglin; Diao, Hui; Xiao, Yi; Li, Wenxia; Yu, Bing; He, Jun; Yu, Jie; Zheng, Ping; Mao, Xiangbing; Luo, Yuheng; Zeng, Benhua; Wei, Hong; Chen, Daiwen

    2016-01-01

    Obesity causes changes in microbiota composition, and an altered gut microbiota can transfer obesity-associated phenotypes from donors to recipients. Obese Rongchang pigs (RP) exhibited distinct fiber characteristics and lipid metabolic profiles in their muscle compared with lean Yorkshire pigs (YP). However, whether RP have a different gut microbiota than YP and whether there is a relationship between the microbiota and muscle properties are poorly understood. The present study was conducted to test whether the muscle properties can be transferred from pigs to germ-free (GF) mice. High-throughput pyrosequencing confirms the presence of distinct core microbiota between pig breeds, with alterations in taxonomic distribution and modulations in β diversity. RP displayed a significant higher Firmicutes/Bacteroidetes ratio and apparent genera differences compared with YP. Transplanting the porcine microbiota into GF mice replicated the phenotypes of the donors. RP and their GF mouse recipients exhibited a higher body fat mass, a higher slow-contracting fiber proportion, a decreased fiber size and fast IIb fiber percentage, and enhanced lipogenesis in the gastrocnemius muscle. Furthermore, the gut microbiota composition of colonized mice shared high similarity with their donor pigs. Taken together, the gut microbiota of obese pigs intrinsically influences skeletal muscle development and the lipid metabolic profiles. PMID:27545196

  6. Fiber type specific response of skeletal muscle satellite cells to high-intensity resistance training in dialysis patients

    DEFF Research Database (Denmark)

    Molsted, Stig; Andersen, Jesper Løvind; Harrison, Adrian Paul;

    2015-01-01

    Introduction. The aim was to investigate the effect of high-intensity resistance training on satellite cell (SC) and myonuclear number in the muscle of patients undergoing dialysis. Methods. Patients (n=21) underwent a 16-week control period, followed by 16 weeks of resistance training thrice...... fibers of dialysis patients who perform resistance training suggests that satellite cell dysfunction is not the limiting factor for muscle growth. This article is protected by copyright. All rights reserved....

  7. Unilateral lower limb suspension does not mimic bed rest or spaceflight effects on human muscle fiber function

    Science.gov (United States)

    Widrick, J. J.; Trappe, S. W.; Romatowski, J. G.; Riley, D. A.; Costill, D. L.; Fitts, R. H.

    2002-01-01

    We used Ca2+-activated skinned muscle fibers to test the hypothesis that unilateral lower leg suspension (ULLS) alters cross-bridge mechanisms of muscle contraction. Soleus and gastrocnemius biopsies were obtained from eight subjects before ULLS, immediately after 12 days of ULLS (post-0 h), and after 6 h of reambulation (post-6 h). Post-0 h soleus fibers expressing type I myosin heavy chain (MHC) showed significant reductions in diameter, absolute and specific peak Ca2+-activated force, unloaded shortening velocity, and absolute and normalized peak power. Fibers obtained from the gastrocnemius were less affected by ULLS, particularly fibers expressing fast MHC isoforms. Post-6 h soleus fibers produced less absolute and specific peak force than did post-0 h fibers, suggesting that reambulation after ULLS induced cell damage. Like bed rest and spaceflight, ULLS primarily affects soleus over gastrocnemius fibers. However, in contrast to these other models, slow soleus fibers obtained after ULLS showed a decrease in unloaded shortening velocity and a greater reduction in specific force.

  8. Adaptive evolution of sexual systems in pedunculate barnacles

    DEFF Research Database (Denmark)

    Yusa, Yoichi; Yoshikawa, Mai; Kitaura, Jun;

    2012-01-01

    How and why diverse sexual systems evolve are fascinating evolutionary questions, but few empirical studies have dealt with these questions in animals. Pedunculate (gooseneck) barnacles show such diversity, including simultaneous hermaphroditism, coexistence of dwarf males and hermaphrodites (and...

  9. Antennular specialization in cyprids of coral associated barnacles

    DEFF Research Database (Denmark)

    Brinckner, I.; Høeg, Jens Thorvald

    2010-01-01

    We used video, light and scanning electron microscopy to study the cypris larvae in species of coral inhabiting barnacles (Pyrgomatidae) in search of adaptations to settlement on their highly unusual substratum. Species studied were Savignium crenatum, Trevathana jensi, Trevathana margaretae...

  10. Effects of strength training on muscle fiber types and size; consequences for athletes training for high-intensity sport

    DEFF Research Database (Denmark)

    Andersen, J L; Aagaard, P

    2010-01-01

    of the muscle and finally how will this affect the performance of the athlete. In addition, the review will deal with muscle hypertrophy and how it develops with strength training. Overall, it is not the purpose of this review to give a comprehensive up-date of the area, but to pin-point a few issues...... way into almost all sports in which high intense work is conducted. In this review we will focus on a few selected aspects and consequences of strength training; namely what effects do strength training have of muscle fiber type composition, and how may these effects change the contractile properties...

  11. In ovo monitoring of smooth muscle fiber development in the chick embryo: diffusion tensor imaging with histologic correlation.

    Directory of Open Access Journals (Sweden)

    Jianrong Xu

    Full Text Available BACKGROUND: Magnetic resonance imaging is a noninvasive method of evaluating embryonic development. Magnetic resonance diffusion tensor imaging, which is based on the measuring the directional diffusivity of water molecules, is an established method of evaluating tissue structure. Prolonged imaging times have precluded the use of embryonic diffusion tensor imaging due to motion artifact. Using temperature-based motion suppression, we aimed to investigate whether diffusion tensor imaging can be used to monitor embryonic smooth muscle development in ovo, and to determine the correlation between histologically-derived muscle fiber fraction, day of incubation and diffusion tensor imaging fractional anisotropy values and length of tracked fibers. METHODOLOGY/PRINCIPAL FINDINGS: From a set of 82 normally developing fertile chicken eggs, 5 eggs were randomly chosen each day from incubation days 5 to 18 and cooled using a dual-cooling technique prior to and during magnetic resonance imaging at 3.0 Tesla. Smooth muscle fibers of the gizzard were tracked using region of interests placed over the gizzard. Following imaging, the egg was cracked and the embryo was fixated and sectioned, and a micrograph most closely corresponding to the acquired magnetic resonance image was made. Smooth muscle fiber fraction was determined using an automated computer algorithm. CONCLUSIONS/SIGNIFICANCE: We show that diffusion tensor images of smooth muscle within the embryonic gizzard can be acquired in ovo from incubation day 11 through hatching. Length of tracked fibers and day of incubation were found to have statistical significance (p<0.05 by multiple linear regression correlation with histologic specimens of sacrificed embryos from day 11 of incubation through hatching. The morphologic pattern of development in our histologic specimens corresponds to the development of embryonic gizzard as reported in the literature. These results suggest that diffusion tensor imaging

  12. Effects of low level laser in the morphology of the skeletal muscle fiber during compensatory hypertrophy in plantar muscle of rats

    Science.gov (United States)

    Terena, Stella Maris Lins; Fernandes, Kristianne Porta Santos; Kalil, Sandra; Alves, Agnelo Neves; Mesquita Ferrari, Raquel Agnelli

    2015-06-01

    The hypertrophy is known as an increase the cross-sectional area of the muscle as a result of a muscular work against an overload, and it is compensatory because the overload is induced by functional elimination of synergistic muscles. The importance of study the compensatory hypertrophy is understand how this process can be influenced by the irradiation with regard to the weight and muscle cross-sectional area, to assist in the rehabilitation process and the effectiveness functional return. The aim was evaluate the effects of low-level laser irradiation on morphological aspects of muscle tissue, comparing the weight and cross-sectional area in rat skeletal muscle. Wistar rats were divided into three groups: control, hypertrophy group without irradiation (right plantar muscle) and hypertrophy group and irradiation (left plantar muscle), both analyzed after 7 and 14 days. The irradiation was performed daily immediately after the surgery. The parameters were: λ = 780nm, beam spot of 0.04 cm2, output power of 40mW, power density of 1W/cm2, energy density of 10J / cm2 and 10s exposure time with a total energy of 3.2 J. The results revealed that low level laser irradiation an increase the weight of the plantaris muscle after 7 and 14 days with a difference of 7.06% and 11.51% respectively. In conclusion, low level laser irradiation has an effect on compensatory hypertrophy to produce increased muscle weight and promoted an increase in cross-sectional area of muscle fibers in the compensatory hypertrophy model after 14 days with parameters cited above.

  13. pH buffering of single rat skeletal muscle fibers in the in vivo environment.

    Science.gov (United States)

    Tanaka, Yoshinori; Inagaki, Tadakatsu; Poole, David C; Kano, Yutaka

    2016-05-15

    Homeostasis of intracellular pH (pHi) has a crucial role for the maintenance of cellular function. Several membrane transporters such as lactate/H(+) cotransporter (MCT), Na(+)/H(+) exchange transporter (NHE), and Na(+)/HCO3 (-) cotransporter (NBC) are thought to contribute to pHi regulation. However, the relative importance of each of these membrane transporters to the in vivo recovery from the low pHi condition is unknown. Using an in vivo bioimaging model, we pharmacologically inhibited each transporter separately and all transporters together and then evaluated the pHi recovery profiles following imposition of a discrete H(+) challenge loaded into single muscle fibers by microinjection. The intact spinotrapezius muscle of adult male Wistar rats (n = 72) was exteriorized and loaded with the fluorescent probe 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein-acetoxymethyl ester (10 μM). A single muscle fiber was then loaded with low-pH solution [piperazine-N,N'-bis(2-ethanesulfonic acid) buffer, pH 6.5, ∼2.33 × 10(-3) μl] by microinjection over 3 s. The rats were divided into groups for the following treatments: 1) no inhibitor (CONT), 2) MCT inhibition (by α-Cyano-4-hydroxyciannamic acid; 4 mM), 3) NHE inhibition (by ethylisopropyl amiloride; 0.5 mM), 4) NBC inhibition (by DIDS; 1 mM), and 5) MCT, NHE, and NBC inhibition (All blockade). The fluorescence ratio (F500 nm/F445 nm) was determined from images captured during 1 min (60 images/min) and at 5, 10, 15, and 20 min after injection. The pHi at 1-2 s after injection significantly decreased from resting pHi (ΔpHi = -0.73 ± 0.03) in CONT. The recovery response profile was biphasic, with an initial rapid and close-to-exponential pHi increase (time constant, τ: 60.0 ± 7.9 s). This initial rapid profile was not affected by any pharmacological blockade but was significantly delayed by carbonic anhydrase inhibition. In contrast, the secondary, more gradual, return toward baseline that restored CONT pHi to

  14. Experiment K-7-21: Effect of Microgravity on 1: Metabolic Enzymes of Type 1 and Type 2 Muscle Fibers, and on 2: Metabolic Enzymes, Neurotransmitter Amino Acids, and Neurotransmitter Associated Enzymes in Selected Regions of the Central Nervous System. Part 1; Metabolic Enzymes of Individual Muscle Fibers

    Science.gov (United States)

    Lowry, O. H.; Ilyina-Kakueva, E. I.; Krasnov, I. B.; Carter, J. G.; Chi, M. M.-Y.; Choksi, R.; Manchester, J. K.; McDougal, D. B.; Nemeth, P. M.; Pusateri, M. E.

    1994-01-01

    Individual fibers of any given muscle vary widely in enzyme composition, a fact obscured when enzyme levels of whole muscle are measured. Therefore, the purpose of this part of the study was to assess the effects of microgravity and hind limb suspension on the enzyme patterns within a slow twitch muscle (soleus) and a fast twitch muscle (tibialis anterior).

  15. Effects of acute exposure of heavy ion to spinal cord on the properties of motoneurons and muscle fibers in rats

    International Nuclear Information System (INIS)

    We investigate effects of localized exposure of heavy ion to the lumbar 4th to 6th segments of the rat spinal cord on the properties of motoneurons and the innervated muscle fibers without surgical treatments. Twenty 7-week-old male Wistar rats were exposed to 5 mm spread-out Bragg peak (SOBP) carbon beam (290 MeV, linear energy transfer (LET)=130 keV/μm): Two doses (15 Gy or 20 Gy) were applied to each group of rats (n=5) in two different depths; one group was exposed only for ventral horn of the spinal cord while other for whole spinal cord. Five rats served as controls. The rats were exposed to carbon irons on October 26, 2002. We will sacrifice the rats soon after they show an abnormal behavior including posture and walking. Cell body size and oxidative enzyme activity of spinal motoneurons of the control and heavy-ion-exposed rats will be analyzed. In addition, cell size, oxidative enzyme activity, and expressions of myosin heavy chain isoforms of the gastrocnemius, soleus, plantaris, extensor digitorum longus, and tibialis anterior muscle fibers will be also determined. This study is performed to test our hypothesis that atrophy and a decrease in cross-sectional area of motoneurons and muscle fibers which they innervate, as well as a decrease in oxidative activity of motoneurons and muscle fibers, will be induced due to exposure to heavy ion. (author)

  16. Hypokalemic periodic paralysis in primary hyperaldosteronism. Subclinical myopathy with atrophy of the type 2A muscle fibers.

    Science.gov (United States)

    Bautista, J; Gil-Neciga, E; Gil-Peralta, A

    1979-01-01

    A case of a patient suffering from primary hyperaldosteronism is reported. In this case the disease is manifested clinically by periodic paralysis and hypopotasemia without permanent myopathy. The morphological study of the muscle demonstrates selective atrophy of the type 2A fibers as the most pronounced alteration. These findings suggest a chronic myopathic process. PMID:546663

  17. Energy composition of diet affects muscle fiber recruitment, body composition, and growth trajectory in rainbow trout (Oncorhnychus mykiss)

    Science.gov (United States)

    Energy composition of diet affects muscle fiber recruitment, body composition, and growth trajectory in rainbow trout (Oncorhnychus mykiss) The cost and scarcity of key ingredients for aquaculture feed formulation call for a wise use of resources, especially dietary proteins and energy. For years t...

  18. Wnt/β-catenin signaling via Axin2 is required for myogenesis and, together with YAP/Taz and Tead1, active in IIa/IIx muscle fibers.

    Science.gov (United States)

    Huraskin, Danyil; Eiber, Nane; Reichel, Martin; Zidek, Laura M; Kravic, Bojana; Bernkopf, Dominic; von Maltzahn, Julia; Behrens, Jürgen; Hashemolhosseini, Said

    2016-09-01

    Canonical Wnt/β-catenin signaling plays an important role in myogenic differentiation, but its physiological role in muscle fibers remains elusive. Here, we studied activation of Wnt/β-catenin signaling in adult muscle fibers and muscle stem cells in an Axin2 reporter mouse. Axin2 is a negative regulator and a target of Wnt/β-catenin signaling. In adult muscle fibers, Wnt/β-catenin signaling is only detectable in a subset of fast fibers that have a significantly smaller diameter than other fast fibers. In the same fibers, immunofluorescence staining for YAP/Taz and Tead1 was detected. Wnt/β-catenin signaling was absent in quiescent and activated satellite cells. Upon injury, Wnt/β-catenin signaling was detected in muscle fibers with centrally located nuclei. During differentiation of myoblasts expression of Axin2, but not of Axin1, increased together with Tead1 target gene expression. Furthermore, absence of Axin1 and Axin2 interfered with myoblast proliferation and myotube formation, respectively. Treatment with the canonical Wnt3a ligand also inhibited myotube formation. Wnt3a activated TOPflash and Tead1 reporter activity, whereas neither reporter was activated in the presence of Dkk1, an inhibitor of canonical Wnt signaling. We propose that Axin2-dependent Wnt/β-catenin signaling is involved in myotube formation and, together with YAP/Taz/Tead1, associated with reduced muscle fiber diameter of a subset of fast fibers. PMID:27578179

  19. Evidence for myoblast-extrinsic regulation of slow myosin heavy chain expression during muscle fiber formation in embryonic development.

    Science.gov (United States)

    Cho, M; Webster, S G; Blau, H M

    1993-05-01

    Vertebrate muscles are composed of an array of diverse fast and slow fiber types with different contractile properties. Differences among fibers in fast and slow MyHC expression could be due to extrinsic factors that act on the differentiated myofibers. Alternatively, the mononucleate myoblasts that fuse to form multinucleated muscle fibers could differ intrinsically due to lineage. To distinguish between these possibilities, we determined whether the changes in proportion of slow fibers were attributable to inherent differences in myoblasts. The proportion of fibers expressing slow myosin heavy chain (MyHC) was found to change markedly with time during embryonic and fetal human limb development. During the first trimester, a maximum of 75% of fibers expressed slow MyHC. Thereafter, new fibers formed which did not express this MyHC, so that the proportion of fibers expressing slow MyHC dropped to approximately 3% of the total by midgestation. Several weeks later, a subset of the new fibers began to express slow MyHC and from week 30 of gestation through adulthood, approximately 50% of fibers were slow. However, each myoblast clone (n = 2,119) derived from muscle tissues at six stages of human development (weeks 7, 9, 16, and 22 of gestation, 2 mo after birth and adult) expressed slow MyHC upon differentiation. We conclude from these results that the control of slow MyHC expression in vivo during muscle fiber formation in embryonic development is largely extrinsic to the myoblast. By contrast, human myoblast clones from the same samples differed in their expression of embryonic and neonatal MyHCs, in agreement with studies in other species, and this difference was shown to be stably heritable. Even after 25 population doublings in tissue culture, embryonic stage myoblasts did not give rise to myoblasts capable of expressing MyHCs typical of neonatal stages, indicating that stage-specific differences are not under the control of a division dependent mechanism, or

  20. An optimized histochemical method to assess skeletal muscle glycogen and lipid stores reveals two metabolically distinct populations of type I muscle fibers.

    Directory of Open Access Journals (Sweden)

    Clara Prats

    Full Text Available Skeletal muscle energy metabolism has been a research focus of physiologists for more than a century. Yet, how the use of intramuscular carbohydrate and lipid energy stores are coordinated during different types of exercise remains a subject of debate. Controversy arises from contradicting data from numerous studies, which used different methodological approaches. Here we review the "pros and cons" of previously used histochemical methods and describe an optimized method to ensure the preservation and specificity of detection of both intramyocellular carbohydrate and lipid stores. For optimal preservation of muscle energy stores, air drying cryosections or cycles of freezing-thawing need to be avoided. Furthermore, optimization of the imaging settings in order to specifically image intracellular lipid droplets stained with oil red O or Bodipy-493/503 is shown. When co-staining lipid droplets with associated proteins, Bodipy-493/503 should be the dye of choice, since oil red O creates precipitates on the lipid droplets blocking the light. In order to increase the specificity of glycogen stain, an antibody against glycogen is used. The resulting method reveals the existence of two metabolically distinct myosin heavy chain I expressing fibers: I-1 fibers have a smaller crossectional area, a higher density of lipid droplets, and a tendency to lower glycogen content compared to I-2 fibers. Type I-2 fibers have similar lipid content than IIA. Exhaustive exercise lead to glycogen depletion in type IIA and IIX fibers, a reduction in lipid droplets density in both type I-1 and I-2 fibers, and a decrease in the size of lipid droplets exclusively in type I-1 fibers.

  1. A myostatin inhibitor (propeptide-Fc) increases muscle mass and muscle fiber size in aged mice but does not increase bone density or bone strength.

    Science.gov (United States)

    Arounleut, Phonepasong; Bialek, Peter; Liang, Li-Fang; Upadhyay, Sunil; Fulzele, Sadanand; Johnson, Maribeth; Elsalanty, Mohammed; Isales, Carlos M; Hamrick, Mark W

    2013-09-01

    Loss of muscle and bone mass with age are significant contributors to falls and fractures among the elderly. Myostatin deficiency is associated with increased muscle mass in mice, dogs, cows, sheep and humans, and mice lacking myostatin have been observed to show increased bone density in the limb, spine, and jaw. Transgenic overexpression of myostatin propeptide, which binds to and inhibits the active myostatin ligand, also increases muscle mass and bone density in mice. We therefore sought to test the hypothesis that in vivo inhibition of myostatin using an injectable myostatin propeptide (GDF8 propeptide-Fc) would increase both muscle mass and bone density in aged (24 mo) mice. Male mice were injected weekly (20 mg/kg body weight) with recombinant myostatin propeptide-Fc (PRO) or vehicle (VEH; saline) for four weeks. There was no difference in body weight between the two groups at the end of the treatment period, but PRO treatment significantly increased mass of the tibialis anterior muscle (+ 7%) and increased muscle fiber diameter of the extensor digitorum longus (+ 16%) and soleus (+ 6%) muscles compared to VEH treatment. Bone volume relative to total volume (BV/TV) of the femur calculated by microCT did not differ significantly between PRO- and VEH-treated mice, and ultimate force (Fu), stiffness (S), toughness (U) measured from three-point bending tests also did not differ significantly between groups. Histomorphometric assays also revealed no differences in bone formation or resorption in response to PRO treatment. These data suggest that while developmental perturbation of myostatin signaling through either gene knockout or transgenic inhibition may alter both muscle and bone mass in mice, pharmacological inhibition of myostatin in aged mice has a more pronounced effect on skeletal muscle than on bone. PMID:23832079

  2. Effect of temperature on crossbridge force changes during fatigue and recovery in intact mouse muscle fibers.

    Directory of Open Access Journals (Sweden)

    Marta Nocella

    Full Text Available Repetitive or prolonged muscle contractions induce muscular fatigue, defined as the inability of the muscle to maintain the initial tension or power output. In the present experiments, made on intact fiber bundles from FDB mouse, fatigue and recovery from fatigue were investigated at 24°C and 35°C. Force and stiffness were measured during tetani elicited every 90 s during the pre-fatigue control phase and recovery and every 1.5 s during the fatiguing phase made of 105 consecutive tetani. The results showed that force decline could be split in an initial phase followed by a later one. Loss of force during the first phase was smaller and slower at 35°C than at 24°C, whereas force decline during the later phase was greater at 35°C so that total force depression at the end of fatigue was the same at both temperatures. The initial force decline occurred without great reduction of fiber stiffness and was attributed to a decrease of the average force per attached crossbridge. Force decline during the later phase was accompanied by a proportional stiffness decrease and was attributed to a decrease of the number of attached crossbridge. Similarly to fatigue, at both 24 and 35°C, force recovery occurred in two phases: the first associated with the recovery of the average force per attached crossbridge and the second due to the recovery of the pre-fatigue attached crossbridge number. These changes, symmetrical to those occurring during fatigue, are consistent with the idea that, i initial phase is due to the direct fast inhibitory effect of [Pi]i increase during fatigue on crossbridge force; ii the second phase is due to the delayed reduction of Ca(2+ release and /or reduction of the Ca(2+ sensitivity of the myofibrils due to high [Pi]i.

  3. Actions of chiriquitoxin on frog skeletal muscle fibers and implications for the tetrodotoxin/saxitoxin receptor.

    Science.gov (United States)

    Yang, L; Kao, C Y

    1992-10-01

    Chiriquitoxin (CqTX) from the Costa Rican frog Atelopus chiriquensis differs from tetrodoxin (TTX) only in that a glycine residue replaces a methylene hydrogen of the C-11 hydroxymethyl function. On the voltage-clamped frog skeletal muscle fiber, in addition to blocking the sodium channel and unrelated to such an action, CqTX also slows the activation of the fast potassium current in approximately 40% of the muscle fiber population. At pH 7.25, CqTX is as potent as TTX in blocking the sodium channel, with an ED50 of 3.8 nM. Its ED50's at pH 6.50 and 8.25 are 6.8 and 2.3 nM, contrasted with 3.8 and 4.3 nM for TTX. These differences are attributable to changes in the chemical states in the glycine residue. The equipotency of CqTX with TTX at pH 7.25 is explainable by an intramolecular salt bridge between the amino and carboxyl groups of the glycine function, all other surface groups in TTX and CqTX being the same. From available information on these groups and those in saxitoxin (STX), the TTX/STX binding site is deduced to be in a pocket 9.5 A wide, 6 A high, and 5 A deep. The glycine residue of CqTX probably projects out of the entrance to this pocket. Such a view of the binding site could also account for the actions of STX analogues, including the C-11 sulfated gonyautoxins and the 21-sulfocarbamoyl analogues. In the gonyautoxins the sulfate groups are equivalently placed as the glycine in CqTX, whereas in the sulfocarbamoyl toxins the sulfate groups extend the carbamoyl side-chain, leading to steric hinderance to productive binding. PMID:1334120

  4. Effect of exercise at light loads with manipulative resistance on infraspinatus, trapezius (upper fiber) and deltoid (middle fiber) muscle activities in shoulder joint elevation

    OpenAIRE

    Nanba, Yoshifumi; Miyamoto, Shigenori; Takemasa, Seiichi; Uesugi, Masayuki; Inoue, Yuri; Ootani, Yoshitaka; Fujii, Shun; Hirotsu, Takaaki; Tanaka, Hideki

    2015-01-01

    [Purpose] To clarify rotator cuff muscular activity in the raised position of the closed kinetic chain (CKC) exercise. [Subjects] Twenty-nine cases were studied, 19 men and 10 women (average age 21.5 ±4.7 years old, average body weight 60.1 kg ±11.4). [Methods] To determine the effects of the closed kinetic chain exercise on the upper limb, we measured the surface EMG of the infraspinatus muscle, the trapezius (upper fiber) and the deltoid (middle fiber) with the arm elevated. [Results] Our r...

  5. Localization of the human 64kD autoantigen D1 to myofibrils in a subset of extraocular muscle fibers

    Science.gov (United States)

    Conley, C. A.; Fowler, V. M.

    1999-01-01

    PURPOSE. To evaluate the tissue-specific expression pattern of the 64kD human autoantigen D1, a tropomodulin-related protein that may be involved in thyroid-associated ophthalmopathy. METHODS. Recombinant 64kD human autoantigen D1 was generated in a bacterial expression system and used to immunize rabbits. Specific antibodies were affinity-purified and used for Western blots on normal and hyperthyroid rat and rabbit tissue, and immunofluorescence localization on cryosections of rat tissue. RESULTS. Anti-64kD human autoantigen D1 antibodies recognize specifically a approximately 70kD polypeptide in western blots of extraocular muscle, sternothyroid muscle, and smooth muscle. Immunofluorescence staining demonstrates that the 64kD human autoantigen D1 localizes to myofibrils in slow fibers from rat extraocular and sternothyroid muscle. The level of this protein is not altered in extraocular muscles from hyperthyroid rabbits. CONCLUSIONS. The 64kD human autoantigen D1 is expressed in slow fibers of extraocular and sternothyroid muscles as a component of myofibrils, and is not upregulated in conditions of hyperthyroidism.

  6. [Contractile properties of fibers and cytoskeletal proteins of gerbil's hindlimb muscles after space flight].

    Science.gov (United States)

    Lipets, E N; Ponomareva, E V; Ogneva, I V; Vikhliantsev, I M; Karaduleva, E V; Kratashkina, N L; Kuznetsov, S L; Podlubnaia, Z A; Shenkman, B S

    2009-01-01

    The work had the goal to compare the microgravity effects on gerbil's muscles-antagonists, m. soleus and m. tibialis anterior. The animals were exposed in 12-d space microgravity aboard Earth's artificial satellite "Foton-M3". Findings of the analysis of single skinned fibers contractility are 19.7% diminution of the diameter and 21.8% loss of the total contractive force of m. soleus fibers post flight. However, there was no significant difference in calcium sensitivity which agrees with the absence of changes in the relative content of several major cytoskeletal proteins (titin and nebulin ratios to heavy chains of myosin were identical in the flight and control groups) and a slight shifting of the myosin phenotype toward the "fast type" (9%, p < 0.05). These parameters were mostly unaffected by the space flight in m. tibialis anterior. To sum up, the decline of contractility and diminution of gerbil's myofibers after the space flight were less significant as compared with rats and did not impact the sytoskeletal protein ratios. PMID:19711860

  7. In vivo visualization of the levator ani muscle subdivisions using MR fiber tractography with diffusion tensor imaging.

    Science.gov (United States)

    Rousset, Pascal; Delmas, Vincent; Buy, Jean-Noël; Rahmouni, Alain; Vadrot, Dominique; Deux, Jean-François

    2012-09-01

    Understanding the levator ani complex architecture is of major clinical relevance. The aim of this study was to determine the feasibility of magnetic resonance (MR) fiber tractography with diffusion tensor imaging (DTI) as a tool for the three-dimensional (3D) representation of normal subdivisions of the levator ani. Ten young nulliparous female volunteers underwent DTI at 1.5 T MR imaging. Diffusion-weighted axial sequence of the pelvic floor was performed with additional T2-weighted multiplanar sequences for anatomical reference. Fiber tractography for visualization of each Terminologia Anatomica-listed major levator ani subdivision was performed. Numeric muscular fibers extracted after tractography were judged as accurate when localized within the boundaries of the muscle, and inaccurate when projecting out of the boundaries of the muscle. From the fiber tracking of each subdivision the number of numeric fibers (inaccurate and accurate) and a score (from 3 to 0) of the adequacy of the 3D representation were calculated. All but two volunteers completed the protocol. The mean number of accurate fibers was 17 ± 2 for the pubovisceralis, 14 ± 6 for the puborectalis and 1 ± 1 for the iliococcygeus. The quality of the 3D representation was judged as good (score = 2) for the pubovisceralis and puborectalis, and inaccurate (score = 0) for the iliococcygeus. Our study is the first step to a 3D visualization of the three major levator ani subdivisions, which could help to better understand their in vivo functional anatomy. PMID:22757638

  8. Abnormal accumulation of prion protein mRNA in muscle fibers of patients with sporadic inclusion-body myositis and hereditary inclusion-body myopathy.

    OpenAIRE

    Sarkozi, E; Askanas, V.; Engel, W K

    1994-01-01

    Sporadic inclusion-body myositis is the most common progressive muscle disease of older patients. The muscle biopsy demonstrates mononuclear cell inflammation and vacuolated muscle fibers containing paired helical filaments and 6 to 10-nm fibrils, both resembling those of Alzheimer brain, and Congo-red positivity. Hereditary inclusion-body myopathy designates patients cytopathologically similar but without inflammation. In both muscle diseases, prion, and several proteins characteristic of Al...

  9. Effects of Mechanical Over-Loading on the Properties of Soleus Muscle Fibers, with or without Damage, in Wild Type and Mdx Mice

    OpenAIRE

    Terada, Masahiro; Kawano, Fuminori; Ohira, Takashi; Nakai, Naoya; Nishimoto, Norihiro; Ohira, Yoshinobu

    2012-01-01

    Effects of mechanical over-loading on the characteristics of regenerating or normal soleus muscle fibers were studied in dystrophin-deficient (mdx) and wild type (WT) mice. Damage was also induced in WT mice by injection of cardiotoxin (CTX) into soleus muscle. Over-loading was applied for 14 days to the left soleus muscle in mdx and intact and CTX-injected WT mouse muscles by ablation of the distal tendons of plantaris and gastrocnemius muscles. All of the myonuclei in normal muscle of WT mi...

  10. Regenerating nerve fiber innervation of extraocular muscles and motor functional changes following oculomotor nerve injuries at different sites

    Institute of Scientific and Technical Information of China (English)

    Wenchuan Zhang; Massimiliano Visocchi; Eduardo Fernandez; Xuhui Wang; Xinyuan Li; Shiting Li

    2011-01-01

    In the present study, the oculomotor nerves were sectioned at the proximal (subtentorial) and distal (superior orbital fissure) ends and repaired. After 24 weeks, vestibulo-ocular reflex evaluation confirmed that the regenerating nerve fibers following oculomotor nerve injury in the superior orbital fissure had a high level of specificity for innervating extraocular muscles. The level of functional recovery of extraocular muscles in rats in the superior orbital fissure injury group was remarkably superior over that in rats undergoing oculomotor nerve injuries at the proximal end (subtentorium). Horseradish peroxidase retrograde tracing through the right superior rectus muscle showed that the distribution of neurons in the nucleus of the oculomotor nerve was directly associated with the injury site, and that crude fibers were badly damaged. The closer the site of injury of the oculomotor nerve was to the extraocular muscle, the better the recovery of neurological function was. The mechanism may be associated with the aberrant number of regenerated nerve fibers passing through the injury site.

  11. Cytosolic calcium transients are a determinant of contraction-induced HSP72 transcription in single skeletal muscle fibers.

    Science.gov (United States)

    Stary, Creed M; Hogan, Michael C

    2016-05-15

    The intrinsic activating factors that induce transcription of heat shock protein 72 (HSP72) in skeletal muscle following exercise remain unclear. We hypothesized that the cytosolic Ca(2+) transient that occurs with depolarization is a determinant. We utilized intact, single skeletal muscle fibers from Xenopus laevis to test the role of the cytosolic Ca(2+) transient and several other exercise-related factors (fatigue, hypoxia, AMP kinase, and cross-bridge cycling) on the activation of HSP72 transcription. HSP72 and HSP60 mRNA levels were assessed with real-time quantitative PCR; cytosolic Ca(2+) concentration ([Ca(2+)]cyt) was assessed with fura-2. Both fatiguing and nonfatiguing contractions resulted in a significant increase in HSP72 mRNA. As expected, peak [Ca(2+)]cyt remained tightly coupled with peak developed tension in contracting fibers. Pretreatment with N-benzyl-p-toluene sulfonamide (BTS) resulted in depressed peak developed tension with stimulation, while peak [Ca(2+)]cyt remained largely unchanged from control values. Despite excitation-contraction uncoupling, BTS-treated fibers displayed a significant increase in HSP72 mRNA. Treatment of fibers with hypoxia (Po2: effect on HSP72 mRNA levels. These results suggest that the intermittent cytosolic Ca(2+) transient that occurs with skeletal muscle depolarization provides a sufficient activating stimulus for HSP72 transcription. Metabolic or mechanical factors associated with fatigue development and cross-bridge cycling likely play a more limited role. PMID:26869714

  12. Structure of Skeletal Muscle

    Science.gov (United States)

    ... and in some they are oblique. Each skeletal muscle fiber is a single cylindrical muscle cell. An individual ... made up of hundreds, or even thousands, of muscle fibers bundled together and wrapped in a connective tissue ...

  13. Repression of slow myosin heavy chain 2 gene expression in fast skeletal muscle fibers by muscarinic acetylcholine receptor and Gαq signaling

    OpenAIRE

    Jordan, Theresa; Li, Jinyuan; Jiang, Hongbin; DiMario, Joseph X.

    2003-01-01

    Gene expression in skeletal muscle fibers is regulated by innervation and intrinsic fiber properties. To determine the mechanism of repression of slow MyHC2 expression in innervated fast pectoralis major (PM) fibers, we investigated the function of the muscarinic acetylcholine receptor (mAchR) and Gαq. Both mAchR and Gαq are abundant in medial adductor (MA) and PM fibers, and mAchR and Gαq interact in these fibers. Whereas innervation of PM fibers was insufficient to induce slow MyHC2 express...

  14. Elemental microchemistry, fatty acid profile and geometric morphometrics signatures of goose barnacles (Pollicipes pollicipes reveal their place of origin

    Directory of Open Access Journals (Sweden)

    Rui Albuquerque

    2014-06-01

    Full Text Available Seafood plays an important role in the socioeconomic, gastronomy and cultural heritage of Portuguese coastal communities. In the Iberian Peninsula, the goose barnacle Pollicipes pollicipes is the intertidal biological resource most heavily exploited by man, resulting on overexploitation of stocks. In the MPA of BNR P.pollicipes harvesting is however strictly regulated, making it a good example of marine resources management. Analytical methods able to identify the origin of goose barnacle would be an important tool to help the management of the trade. For such purpose, we investigated whether P. pollicipes have site-specific differences based on its elemental microchemistry (EM, fatty acid profile (FA and capitulum shape (CS. The analysis was performed on specimens collected from 3 sites in the BNR and 7 along a 300 km stretch of the Portuguese coast. For each individual we analysed the largest lateral shell for EM using ICP-MS, the FA content of the muscle using GC-FID, and the CS using geometric morphometrics. Discriminant function analyses (DFA for both EM and FA separately provided a high reclassification success (77.6% and 99% respectively, of cross-validated cases correctly classified, while for EM combined with FA allowed for a 100% reclassification success. DFA analysis based only on CS, revealed a low classification success (29.6%. These results show that EM and FA signatures can be a powerful tool to infer goose barnacles origin. Such “fingerprinting” approach can be used to track and identify goose barnacles origin, helping in establishing an origin certificate and increasing the potential value of biological resources from Portuguese MPAs.

  15. Effects of ractopamine administration and castration method on muscle fiber characteristics and sensory quality of the longissimus muscle in two Piétrain pig genotypes.

    Science.gov (United States)

    Li, Hui; Gariépy, Claude; Jin, Ye; Font I Furnols, Maria; Fortin, Jacinthe; Rocha, Luiene M; Faucitano, Luigi

    2015-04-01

    Single and combined effects of ractopamine supplementation (RAC, 7.5 vs. 0 ppm), castration method (surgical castration: SC vs. immuno-castration: IM) and genotype (genotype A: GA vs. GB containing 25% or 50% Piétrain) were determined on longissimus muscle (LM) fiber traits and quality of pork (n=512). RAC increased fiber IIX cross-sectional area (P=0.009) and decreased glycolytic potential (P=0.02) and pork tenderness (P<0.001). Fiber traits indicated that LM of IM pigs was more oxidative (P<0.05) and meat had slightly higher (P=0.04) off-flavor score and WBSF than SC. LM from GB pigs was paler (P<0.05) and had greater (P<0.05) glycolytic potential, IIX fiber cross sectional area and pork off-flavor than GA. RAC supplementation, castration method and genotype or their combination affected some fiber traits and some quality parameters but differences reported were small indicating these treatments or their combination could be used without major prejudice to meat quality. PMID:25529286

  16. Smooth Muscle Cell Alignment and Phenotype Control by Melt Spun Polycaprolactone Fibers for Seeding of Tissue Engineered Blood Vessels

    Directory of Open Access Journals (Sweden)

    Animesh Agrawal

    2015-01-01

    Full Text Available A method has been developed to induce and retain a contractile phenotype for vascular smooth muscle cells, as the first step towards the development of a biomimetic blood vessel construct with minimal compliance mismatch. Melt spun PCL fibers were deposited on a mandrel to form aligned fibers of 10 μm in diameter. The fibers were bonded into aligned arrangement through dip coating in chitosan solution. This formed a surface of parallel grooves, 10 μm deep by 10 μm across, presenting a surface layer of chitosan to promote cell surface interactions. The aligned fiber surface was used to culture cells present in the vascular wall, in particular fibroblasts and smooth muscle cells. This topography induced “surface guidance” over the orientation of the cells, which adopted an elongated spindle-like morphology, whereas cells on the unpatterned control surface did not show such orientation, assuming more rhomboid shapes. The preservation of VSMC contractile phenotype on the aligned scaffold was demonstrated by the retention of α-SMA expression after several days of culture. The effect was assessed on a prototype vascular graft prosthesis fabricated from polylactide caprolactone; VSMCs aligned longitudinally along a fiberless tube, whereas, for the aligned fiber coated tubes, the VSMCs aligned in the required circumferential orientation.

  17. A Novel Fiber Bragg Grating Based Sensing Methodology for Direct Measurement of Surface Strain on Body Muscles during Physical Exercises

    Science.gov (United States)

    Prasad Arudi Subbarao, Guru; Subbaramajois Narasipur, Omkar; Kalegowda, Anand; Asokan, Sundarrajan

    2012-07-01

    The present work proposes a new sensing methodology, which uses Fiber Bragg Gratings (FBGs) to measure in vivo the surface strain and strain rate on calf muscles while performing certain exercises. Two simple exercises, namely ankle dorsi-flexion and ankle plantar-flexion, have been considered and the strain induced on the medial head of the gastrocnemius muscle while performing these exercises has been monitored. The real time strain generated has been recorded and the results are compared with those obtained using a commercial Color Doppler Ultrasound (CDU) system. It is found that the proposed sensing methodology is promising for surface strain measurements in biomechanical applications.

  18. Effect of spaceflight on the maximal shortening velocity, morphology, and enzyme profile of fast- and slow-twitch skeletal muscle fibers in rhesus monkeys

    Science.gov (United States)

    Fitts, R. H.; Romatowski, J. G.; De La Cruz, L.; Widrick, J. J.; Desplanches, D.

    2000-01-01

    Weightlessness has been shown to cause limb muscle wasting and a reduced peak force and power in the antigravity soleus muscle. Despite a reduced peak power, Caiozzo et al. observed an increased maximal shortening velocity in the rat soleus muscle following a 14-day space flight. The major purpose of the present investigation was to determine if weightlessness induced an elevated velocity in the antigravity slow type I fibers of the rhesus monkey (Macaca mulatta), as well as to establish a cellular mechanism for the effect. Spaceflight or models of weightlessness have been shown to increase glucose uptake, elevate muscle glycogen content, and increase fatigability of the soleus muscle. The latter appears to be in part caused by a reduced ability of the slow oxidative fibers to oxidize fats. A second goal of this study was to establish the extent to which weightlessness altered the substrate profile and glycolytic and oxidative enzyme capacity of individual slow- and fast-twitch fibers.

  19. The Preventive Effects of 8 Weeks of Resistance Training on Glucose Tolerance and Muscle Fiber Type Composition in Zucker Rats

    OpenAIRE

    Ji-yeon Kim; Mi Jung Choi; Byunghun So; Hee-jae Kim; Je Kyung Seong; Wook Song

    2015-01-01

    Background We investigated the therapeutic effects of resistance training on Zucker rats before and after the onset of diabetes to understand the importance of the timing of exercise intervention. We assessed whether 8 weeks of resistance training ameliorated impaired glucose tolerance and altered muscle fiber type composition in Zucker rats. Methods Five-week-old male Zucker rats were divided into Zucker lean control (ZLC-Con), non-exercised Zucker diabetic fatty (ZDF-Con), and exercised Zuc...

  20. Skeletal Muscle Hypertrophy Following Resistance Training Is Accompanied by a Fiber Type–Specific Increase in Satellite Cell Content in Elderly Men

    OpenAIRE

    Verdijk, Lex B; Gleeson, Benjamin G.; Jonkers, Richard A. M.; Meijer, Kenneth; Hans H C M Savelberg; Dendale, Paul; Luc J. C. Van Loon

    2009-01-01

    We determined muscle fiber type–specific hypertrophy and changes in satellite cell (SC) content following a 12-week resistance training program in 13 healthy, elderly men (72 ± 2 years). Leg strength and body composition (dual-energy X-ray absorptiometry and computed tomography) were assessed, and muscle biopsy samples were collected. Leg strength increased 25%–30% after training (p < .001). Leg lean mass and quadriceps cross-sectional area increased 6%–9% (p < .001). At baseline, mean fiber ...

  1. ROS-mediated decline in maximum Ca2+-activated force in rat skeletal muscle fibers following in vitro and in vivo stimulation.

    Science.gov (United States)

    Dutka, Travis L; Verburg, Esther; Larkins, Noni; Hortemo, Kristin H; Lunde, Per K; Sejersted, Ole M; Lamb, Graham D

    2012-01-01

    We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were bubbled with 95% O(2) and stimulated in vitro at 31°C to give isometric tetani (50 Hz for 0.5 s every 2 s) until maximum force declined to ≤30%. Skinned superficial slow-twitch fibers from the SOL muscles displayed a large reduction (∼41%) in maximum Ca(2+)-activated specific force (F(max)), with Ca(2+)-sensitivity unchanged. Fibers from EDL muscles were less affected. The decrease in F(max) in SOL fibers was evidently due to oxidation effects on cysteine residues because it was reversed if the reducing agent DTT was applied prior to activating the fiber. The GSH:GSSG ratio was ∼3-fold lower in the cytoplasm of superficial fibers from stimulated muscle compared to control, confirming increased oxidant levels. The presence of Tempol and L-NAME during in vitro stimulation prevented reduction in F(max). Skinned fibers from SOL muscles stimulated in vivo at 37°C with intact blood supply also displayed reduction in F(max), though to a much smaller extent (∼12%). Thus, fibers from muscles stimulated even with putatively adequate O(2) supply display a reversible oxidation-induced decrease in F(max) without change in Ca(2+)-sensitivity, consistent with action of peroxynitrite (or possibly superoxide) on cysteine residues of the contractile apparatus. Significantly, the changes closely resemble the contractile deficits observed in a range of pathophysiological conditions. These findings highlight how readily muscle experiences ROS-related deficits, and also point to potential difficulties when defining muscle performance and fatigue. PMID:22629297

  2. An ultrastructural and histochemical study of the flexor tibialis muscle fiber types in male and female stick insects (Eurycantha calcarata, L).

    Science.gov (United States)

    Pilehvarian, Ali Asghar

    2015-10-01

    In this study the ultrastructural and histochemical characteristics of the flexor tibialis muscle fibers of the specialized metathoracic legs in the male and those of homologous and unspecialized ones in the female stick insects, Eurycantha calcarata, L, were examined. For the ultrastructural analysis, the muscle was divided longitudinally and vertically to produce a total of 12 sample parts e.g., anterior-dorsal-distal (ADD), posterior-ventral-medial (PVM) and so on. Light and electron microscopes were used to observe the muscle tissue. The methods for myosin adenosine triphosphatase (mATPase) and nicotine adenine dinucleotide- tetrazolium (NADH-TR) staining were modified from the methods of (Stokes et al., '79; Anttila et al., 2009; Anttila and Manttari, 2009). Sections with thickness of 22 μm, were cut from the anterior and the posterior surfaces of the muscle, using a cryostat. The histochemical and ultrastructural results showed that the muscles of both the male and the female were mixtures of physiological fiber types, with predominantly fast fibers. The muscles were composed of fibers with different staining properties for both mATPase and NADH-TR activities. The population of fibers within the muscles was heterogeneous. The differences between the population of the male and that of the female were significant. The means of most criteria e.g., mitochondrial amount and sarcoplasmic reticulum area predicted that the muscle of the male contained more fast fibers than the female. The histochemical examination also showed that the muscle of the male contained more fibers stained darkly for mATPase and lightly for NADH-TR. PMID:26173440

  3. Effects of carnosine on contractile apparatus Ca²⁺ sensitivity and sarcoplasmic reticulum Ca²⁺ release in human skeletal muscle fibers.

    Science.gov (United States)

    Dutka, T L; Lamboley, C R; McKenna, M J; Murphy, R M; Lamb, G D

    2012-03-01

    There is considerable interest in potential ergogenic and therapeutic effects of increasing skeletal muscle carnosine content, although its effects on excitation-contraction (EC) coupling in human muscle have not been defined. Consequently, we sought to characterize what effects carnosine, at levels attained by supplementation, has on human muscle fiber function, using a preparation with all key EC coupling proteins in their in situ positions. Fiber segments, obtained from vastus lateralis muscle of human subjects by needle biopsy, were mechanically skinned, and their Ca(2+) release and contractile apparatus properties were characterized. Ca(2+) sensitivity of the contractile apparatus was significantly increased by 8 and 16 mM carnosine (increase in pCa(50) of 0.073 ± 0.007 and 0.116 ± 0.006 pCa units, respectively, in six type I fibers, and 0.063 ± 0.018 and 0.103 ± 0.013 pCa units, respectively, in five type II fibers). Caffeine-induced force responses were potentiated by 8 mM carnosine in both type I and II fibers, with the potentiation in type II fibers being entirely explicable by the increase in Ca(2+) sensitivity of the contractile apparatus caused by carnosine. However, the potentiation of caffeine-induced responses caused by carnosine in type I fibers was beyond that expected from the associated increase in Ca(2+) sensitivity of the contractile apparatus and suggestive of increased Ca(2+)-induced Ca(2+) release. Thus increasing muscle carnosine content likely confers benefits to muscle performance in both fiber types by increasing the Ca(2+) sensitivity of the contractile apparatus and possibly also by aiding Ca(2+) release in type I fibers, helping to lessen or slow the decline in muscle performance during fatiguing stimulation. PMID:22174397

  4. Improvement of Endurance Based on Muscle Fiber-Type Composition by Treatment with Dietary Apple Polyphenols in Rats.

    Directory of Open Access Journals (Sweden)

    Wataru Mizunoya

    Full Text Available A recent study demonstrated a positive effect of apple polyphenol (APP intake on muscle endurance of young-adult animals. While an enhancement of lipid metabolism may be responsible, in part, for the improvement, the contributing mechanisms still need clarification. Here we show that an 8-week intake of 5% (w/w APP in the diet, up-regulates two features related to fiber type: the ratio of myosin heavy chain (MyHC type IIx/IIb and myoglobin protein expression in plantaris muscle of 9-week-old male Fischer F344 rats compared to pair-fed controls (P < 0.05. Results were demonstrated by our SDS-PAGE system specialized for MyHC isoform separation and western blotting of whole muscles. Animal-growth profiles (food intake, body-weight gain, and internal-organ weights did not differ between the control and 5% APP-fed animals (n = 9/group. Findings may account for the increase in fatigue resistance of lower hind limb muscles, as evidenced by a slower decline in the maximum isometric planter-flexion torque generated by a 100-s train of electrical stimulation of the tibial nerve. Additionally, the fatigue resistance was lower after 8 weeks of a 0.5% APP diet than after 5% APP, supporting an APP-dose dependency of the shift in fiber-type composition. Therefore, the present study highlights a promising contribution of dietary APP intake to increasing endurance based on fiber-type composition in rat muscle. Results may help in developing a novel strategy for application in animal sciences, and human sports and age-related health sciences.

  5. Single fiber, laser Doppler flowmetry (LDF) for detecting muscle microcirculation in the low leg and its technique improvement

    Science.gov (United States)

    Cai, Hongming; Oberg, P. Ake; Rohman, Hakan; Larsson, Sven-Erik

    1995-02-01

    Percutaneous, single fiber LDF of 632.8 nm (He-Ne) is used for continuous recording of low leg muscle microcirculation. An optical fiber (0 equals 0.5 mm) was placed inside the tibialis ant. muscle 10 cm below the knee joint via a plastic cannula (0 equals 1.0 mm) and using local anaesthesia of the skin. The LDF is sampled continuously by the on-line PC computer one minute before, three minutes during and for four minutes after tourniquet occlusion. Twelve healthy, non-smoking men were examined. The reactive hyperaemia and the flux reactive time after release of tourniquet was examined successfully. To get better signal-to-noise ration and deeper detected volume in the muscle, the optical characteristics of ordinary fiber tips and modified spherical and `pear'-type ends were studied. Compared with the system of 632.8 nm, a new optical system with a laser diode of 790 nm was developed. A PC computer with DSP card was used for all the signal processing in the new system.

  6. Botulinum neurotoxin and chronic migraine: muscle fiber chemodenervation or nociceptic system modulation?

    Directory of Open Access Journals (Sweden)

    A. R. Artemenko

    2015-02-01

    Full Text Available The results of controlled investigations suggest that botulinumtoxin type A (BTA leads to decrease headache intensity and prevent migraine attacks. The antinociceptive mechanisms of BTA action remain unclear. Modern and previous hypothesis of antinociceptive action BTA in chronic migraine (CM are discussed in details. Recent experimental and clinical evidence strongly suggest that BTA has aspecific antinociceptive effect realized through inhibition of proinflammatory neurotransmitters release not only from the sensory terminals but from muscle nociceptors. The mechanism of the action of BTA in CM has more than one target and is considered to involve different pathophysiological levels CM: neurogenic inflammation, peripheral and central sensitization. The administration of BTA on the PREEMPT principle (paradigm ensures optimal neurotoxin distribution in the anatomic areas in accordance with their sensory innervation by cervical segments and sensory fibers in the trigeminal system, the terminal branches which are the major target of BTA in the treatment of CM.

  7. Effects of strength training on muscle fiber types and size; consequences for athletes training for high-intensity sport

    DEFF Research Database (Denmark)

    Andersen, J L; Aagaard, P

    2010-01-01

    Training toward improving performance in sports involving high intense exercise can and is done in many different ways based on a mixture of tradition in the specific sport, coaches' experience and scientific recommendations. Strength training is a form of training that now-a-days have found its...... way into almost all sports in which high intense work is conducted. In this review we will focus on a few selected aspects and consequences of strength training; namely what effects do strength training have of muscle fiber type composition, and how may these effects change the contractile properties...... of the muscle and finally how will this affect the performance of the athlete. In addition, the review will deal with muscle hypertrophy and how it develops with strength training. Overall, it is not the purpose of this review to give a comprehensive up-date of the area, but to pin-point a few issues...

  8. Differentiation of muscle fiber types and expression of myosin heavy chain isoforms in slow and fast rat skeletal muscles re-evaluated

    Czech Academy of Sciences Publication Activity Database

    Přenosil, Ondřej; Žurmanová, Jitka; Horníková, Daniela; Soukup, Tomáš

    Fyziologický ústav AV ČR, v. v. i.. Roč. 57, č. 2 (2008), 26P-27P ISSN 0862-8408. [Fyziologické dny /84./. 06.02.2008-08.02.2008, Martin] R&D Projects: GA MŠk(CZ) LC554; GA ČR(CZ) GA304/05/0327 Grant ostatní: Myores(XE) 511978 Institutional research plan: CEZ:AV0Z50110509 Source of funding: R - rámcový projekt EK Keywords : cpr1 * muscle fiber types * myosin heavy chain isoforms * thyroid hormones Subject RIV: ED - Physiology

  9. Impaired exercise training-induced muscle fiber hypertrophy and Akt/mTOR pathway activation in hypoxemic patients with COPD.

    Science.gov (United States)

    Costes, Frédéric; Gosker, Harry; Feasson, Léonard; Desgeorges, Marine; Kelders, Marco; Castells, Josiane; Schols, Annemie; Freyssenet, Damien

    2015-04-15

    Exercise training (ExTr) is largely used to improve functional capacity in patients with chronic obstructive pulmonary disease (COPD). However, ExTr only partially restores muscle function in patients with COPD, suggesting that confounding factors may limit the efficiency of ExTr. In the present study, we hypothesized that skeletal muscle adaptations triggered by ExTr could be compromised in hypoxemic patients with COPD. Vastus lateralis muscle biopsies were obtained from patients with COPD who were either normoxemic (n = 15, resting arterial Po2 = 68.5 ± 1.5 mmHg) or hypoxemic (n = 8, resting arterial Po2 = 57.0 ± 1.0 mmHg) before and after a 2-mo ExTr program. ExTr induced a significant increase in exercise capacity both in normoxemic and hypoxemic patients with COPD. However, ExTr increased citrate synthase and lactate dehydrogenase enzyme activities only in skeletal muscle of normoxemic patients. Similarly, muscle fiber cross-sectional area and capillary-to-fiber ratio were increased only in patients who were normoxemic. Expression of atrogenes (MuRF1, MAFbx/Atrogin-1) and autophagy-related genes (Beclin, LC3, Bnip, Gabarapl) remained unchanged in both groups. Phosphorylation of Akt (Ser473), GSK-3β (Ser9), and p70S6k (Thr389) was nonsignificantly increased in normoxemic patients in response to ExTr, but it was significantly decreased in hypoxemic patients. We further showed on C2C12 myotubes that hypoxia completely prevented insulin-like growth factor-1-induced phosphorylation of Akt, GSK-3β, and p70S6K. Together, our observations suggest a role for hypoxemia in the adaptive response of skeletal muscle of patients with COPD in an ExTr program. PMID:25701004

  10. Coordinated increase in skeletal muscle fiber area and expression of IGF-I with resistance exercise in elderly post-operative patients

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Suetta, Charlotte Arneboe; Clemmensen, Christoffer;

    2010-01-01

    Hypertrophy of developing skeletal muscle involves stimulation by insulin-like growth factor-I (IGF-I), however, the role of IGF-I in adult muscle is less clarified. In the present study, the mRNA splice variants of IGF-I (IGF-IEa and MGF) and the changes in muscle fiber cross sectional area after...... in addition induces marked increases in the expression of IGF-I splice variants, supporting the idea that IGF-I is involved in regulating muscle hypertrophy.......-operated-side served as a within subject control. Muscle biopsies were obtained from the vastus lateralis of both limbs at +2d post-operative (baseline), at 5weeks and 12weeks post-surgery to analyze for changes in type 1 and type 2 muscle fiber area. Changes in expression levels of IGF-I mRNA isoforms were determined...

  11. Muscle strain (image)

    Science.gov (United States)

    A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...

  12. Effect of cleft palate repair on the susceptibility to contraction-induced injury of single permeabilized muscle fibers from congenitally-clefted goat palates.

    Science.gov (United States)

    Despite cleft palate repair, velopharyngeal competence is not achieved in ~ 15% of patients, often necessitating secondary surgical correction. Velopharyngeal competence postrepair may require the conversion of levator veli palatini muscle fibers from injury-susceptible type 2 fibers to injury-resi...

  13. [Fiber morphometry of the external intercostal muscle. Comparison of dominant and nondominant sides in patients with severe COPD].

    Science.gov (United States)

    Jiménez-Fuentes, M A; Gea, J; Pallás, O; Gallego, F; Félez, M A; Broquetas, J M

    1998-04-01

    The general morphometric characteristics of the external intercostal muscle (EIM) of patients with chronic respiratory disease have been well described. Because this muscle is highly accessible, it can provide an ideal model for longitudinal studies using consecutive biopsies of both sides. Whether or not the EIM fiber phenotype is homogeneous on dominant (D) and non dominant (ND) sides is unknown, however. To evaluate possible structural differences in right and left EIM in patients with COPD, eight patients (63 +/- 7 years of age) were enrolled. Lung function, respiratory muscle power, general muscle power and nutritional state were evaluated. Biopsies of the fifth EIM were taken from both sides. Specimens were processed in parallel manner to determine conventional morphometry (hematoxylin-eosin staining), including minimum diameter (Dm) and fiber area (Ar) in cross sections. Fibers were typed by ATPase (at pH 4.2, 4.6 and 9.4) and NADH-TR staining. Nutrition was normal in all patients. All patients had severe COPD (FEV1 27 +/- 7% of reference, limits 13 to 38% of reference) with air entrapment (RV 163 +/- 36% of reference, limits 181 to 276% of reference). None of the patients showed respiratory insufficiency at rest (PaO2 72 +/- 7 mmHg). Peripheral musculoskeletal power measured by manual dynamometer showed no significant right-left differences: D 29 +/- 2 and ND 28 +/- 3 dynes. Morphometric study of 16 muscle specimens showed no significant differences between fiber size on D and ND sides. DmD was 47 +/- 10 microns and ArD, was 2,595 +/- 1,249 microns2. DmD was 49 +/- 9 microns and ArD was 2,636 +/- 953 microns2. Likewise, no significant differences were found between D and ND fiber types: type ID 51 +/- 4% and type IID 49 +/- 5% versus type IND 52 +/- 4% and type IIND 48 +/- 4%. EIM on N and ND sides is homogeneous at the fifth intercostal space. This finding, along with the scarcely invasive nature of the technique for collecting specimens leads us to

  14. Caloric restriction induces energy-sparing alterations in skeletal muscle contraction, fiber composition and local thyroid hormone metabolism that persist during catch-up fat upon refeeding

    Directory of Open Access Journals (Sweden)

    Paula Bresciani M. De Andrade

    2015-09-01

    Full Text Available Weight regain after caloric restriction results in accelerated fat storage in adipose tissue. This catch-up fat phenomenon is postulated to result partly from suppressed skeletal muscle thermogenesis, but the underlying mechanisms are elusive. We investigated whether the reduced rate of skeletal muscle contraction-relaxation cycle that occurs after caloric restriction persists during weight recovery and could contribute to catch-up fat. Using a rat model of semistarvation-refeeding, in which fat recovery is driven by suppressed thermogenesis, we show that contraction and relaxation of leg muscles are slower after both semistarvation and refeeding. These effects are associated with (i higher expression of muscle deiodinase type 3 (DIO3 which inactivates tri-iodothyronine (T3, and lower expression of T3-activating enzyme, deiodinase type 2 (DIO2, (ii slower net formation of T3 from its T4 precursor in muscles, and (iii accumulation of slow fibers at the expense of fast fibers. These semistarvation-induced changes persisted during recovery and correlated with impaired expression of transcription factors involved in slow-twitch muscle development.We conclude that diminished muscle thermogenesis following caloric restriction results from reduced muscle T3 levels, alteration in muscle-specific transcription factors, and fast-to-slow fiber shift causing slower contractility. Energy-sparing effects persist during weight recovery and likely contribute to catch-up fat.

  15. Electrophysiological effects of haloperidol on isolated rabbit Purkinje fibers and guinea pigs papillary muscles under normal and simulated ischemia

    Institute of Scientific and Technical Information of China (English)

    Dong YAN; Lu-feng CHENG; Hong-yan SONG; Subat TURDI; Parhat KERRAM

    2007-01-01

    Aim: Overdoses of haloperidol are associated with major ventricular arrhythmias,cardiac conduction block, and sudden death. The aim of this experiment was to study the effect of haloperidol on the action potentials in cardiac Purkinje fibers and papillary muscles under normal and simulated ischemia conditions in rabbits and guinea pigs. Methods: Using the standard intracellular microelectrode technique, we examined the effects of haloperidol on the action potential param-eters [action potential amplitude (APA), phase 0 maximum upstroke velocity (Vmax),action potential amplitude at 90% of repolarization (APD90), and effective refrac-tory period (ERP)] in rabbit cardiac Purkinje fibers and guinea pig cardiac papillary cells, in which both tissues were under simulated ischemic conditions. Results: Under ischemic conditions, different concentrations of haloperidol depressed APA and prolonged APD90 in a concentration-dependent manner in rabbit Purkinje fibers. Haloperidol (3 μmol/L) significantly depressed APA and prolonged APD90,and from 1 μmol/L, haloperidol showed significant depression on Vmax; ERP was not significantly affected. In guinea pig cardiac papillary muscles, the thresholds of significant reduction in APA, Vmax, EPR, and APD90 were 10, 0.3, 1, and 1 μmol/L, respectively, for haloperidol. Conclusion: Compared with cardiac con-ductive tissues, papillary muscles were more sensitive to ischemic conditions. Under ischemia, haloperidol prolonged ERP and APD90 in a concentration-depen-dent manner and precipitated the decrease in Vmax induced by ischemia. The shortening of ERP and APD90 in papillary muscle action potentials may be inhibi-ted by haloperidol.

  16. The Preventive Effects of 8 Weeks of Resistance Training on Glucose Tolerance and Muscle Fiber Type Composition in Zucker Rats

    Directory of Open Access Journals (Sweden)

    Ji-yeon Kim

    2015-10-01

    Full Text Available BackgroundWe investigated the therapeutic effects of resistance training on Zucker rats before and after the onset of diabetes to understand the importance of the timing of exercise intervention. We assessed whether 8 weeks of resistance training ameliorated impaired glucose tolerance and altered muscle fiber type composition in Zucker rats.MethodsFive-week-old male Zucker rats were divided into Zucker lean control (ZLC-Con, non-exercised Zucker diabetic fatty (ZDF-Con, and exercised Zucker diabetic fatty (ZDF-Ex groups. The ZDF-Ex rats climbed a ladder three times a week for 8 weeks. Intraperitoneal glucose tolerance tests (IPGTT were performed on the 1st and 8th weeks of training, and grip strength was measured during the last week. We also measured glucose transporter 4 (GLUT4 expression by Western blot and immunofluorescence. Moreover, immunohistochemistry was performed to assess muscle fiber type composition.ResultsFasting glucose levels and area under the curve responses to IPGTTs gradually increased as diabetes progressed in the ZDF-Con rats but decreased in the ZDF-Ex rats. Grip strength decreased in the ZDF-Con rats. However, resistance training did not improve grip strength in the ZDF-Ex rats. GLUT4 expression in the ZLC-Con and the ZDF-Con rats did not differ, but it increased in the ZDF-Ex rats. The proportions of myosin heavy chain I and II were lower and higher, respectively, in the ZDF-Con rats compared to the ZLC-Con rats. Muscle fiber type composition did not change in the ZDF-Ex rats.ConclusionOur results suggest that regular resistance training initiated at the onset of diabetes can improve glucose tolerance and GLUT4 expression without changing muscle morphology in Zucker rats.

  17. Austromegabalanus psittacus barnacle shell structure and proteoglycan localization and functionality.

    Science.gov (United States)

    Fernández, M S; Arias, J I; Neira-Carrillo, A; Arias, J L

    2015-09-01

    Comparative analyzes of biomineralization models have being crucial for the understanding of the functional properties of biominerals and the elucidation of the processes through which biomacromolecules control the synthesis and structural organization of inorganic mineral-based biomaterials. Among calcium carbonate-containing bioceramics, egg, mollusk and echinoderm shells, and crustacean carapaces, have being fairly well characterized. However, Thoraceca barnacles, although being crustacea, showing molting cycle, build a quite stable and heavily mineralized shell that completely surround the animal, which is for life firmly cemented to the substratum. This makes barnacles an interesting model for studying processes of biomineralization. Here we studied the main microstructural and ultrastructural features of Austromegabalanus psittacus barnacle shell, characterize the occurrence of specific proteoglycans (keratan-, dermatan- and chondroitin-6-sulfate proteoglycans) in different soluble and insoluble organic fractions extracted from the shell, and tested them for their ability to crystallize calcium carbonate in vitro. Our results indicate that, in the barnacle model, proteoglycans are good candidates for the modification of the calcite crystal morphology, although the cooperative effect of some additional proteins in the shell could not be excluded. PMID:26276577

  18. A coral-eating barnacle, revisited (Cirripedia, Pyrgomatidae)

    NARCIS (Netherlands)

    Ross, Arnold; Newman, William A.

    1995-01-01

    The coral-eating barnacle Hoekia monticulariae (Gray, 1831), the only internal parasite among the Thoracica described to this day, is characterized by an irregularly-shaped shell nestled cryptically between the polyps of the hermatypic coral Hydnophora Fischer, 1807, which occurs throughout most of

  19. The N-terminal Ac-EEED sequence plays a role in alpha-smooth-muscle actin incorporation into stress fibers

    OpenAIRE

    Clement, Sophie; Hinz, Boris; Dugina, Vera; Gabbiani, Giulio; Chaponnier, Christine

    2005-01-01

    We have previously shown that the N-terminal sequence AcEEED of alpha-smooth-muscle actin causes the loss of alpha-smooth-muscle actin from stress fibers and a decrease in cell contractility when introduced in myofibroblasts as a cell-penetrating fusion peptide. Here, we have investigated the function of this sequence on stress fiber organization in living cells, using enhanced green fluorescent protein (EGFP)-tagged alpha-smooth-muscle actin. The fusion peptide provokes the gradual disappear...

  20. Neuronal Nitric Oxide Synthase Is Dislocated in Type I Fibers of Myalgic Muscle but Can Recover with Physical Exercise Training

    Directory of Open Access Journals (Sweden)

    L. Jensen

    2015-01-01

    Full Text Available Trapezius myalgia is the most common type of chronic neck pain. While physical exercise reduces pain and improves muscle function, the underlying mechanisms remain unclear. Nitric oxide (NO signaling is important in modulating cellular function, and a dysfunctional neuronal NO synthase (nNOS may contribute to an ineffective muscle function. This study investigated nNOS expression and localization in chronically painful muscle. Forty-one women clinically diagnosed with trapezius myalgia (MYA and 18 healthy controls (CON were included in the case-control study. Subsequently, MYA were randomly assigned to either 10 weeks of specific strength training (SST, n=18, general fitness training (GFT, n=15, or health information (REF, n=8. Distribution of fiber type, cross-sectional area, and sarcolemmal nNOS expression did not differ between MYA and CON. However, MYA showed increased sarcoplasmic nNOS localization (18.8 ± 12 versus 12.8 ± 8%, P=0.049 compared with CON. SST resulted in a decrease of sarcoplasm-localized nNOS following training (before 18.1 ± 12 versus after 12.0 ± 12%; P=0,027. We demonstrate that myalgic muscle displays altered nNOS localization and that 10 weeks of strength training normalize these disruptions, which supports previous findings of impaired muscle oxygenation during work tasks and reduced pain following exercise.

  1. Dielectric resonator-based side-access probe for muscle fiber EPR study.

    Science.gov (United States)

    Sienkiewicz, A; Jaworski, M; Smith, B G; Fajer, P G; Scholes, C P

    2000-03-01

    We present a novel dielectric resonator (DR)-based resonant structure that accommodates aqueous sample capillaries in orientations that are either parallel (i.e., side-access) or perpendicular to the direction of an external (Zeeman) magnetic field, B(0). The resonant structure consists of two commercially available X-band DRs that are separated by a Rexolite spacer and resonate in the fundamental TE(01delta) mode. The separator between the DRs is used to tune the resonator to the desired frequency and, by appropriately drilled sample holes, to provide access for longitudinal samples, notably capillaries containing oriented, spin-labeled muscle fibers. In contrast to the topologically similar cylindrical TE(011) cavity, the DR-based structure has distinct microwave properties that favor its use for parallel orientation of lossy aqueous samples. For perpendicular orientation of a dilute (6.25 microM) aqueous solution of IASL spin label, the S/N ratio was at least one order of magnitude better for the side-access DR-based structure than for a standard TE(102) cavity. EPR spectra acquired for maleimide spin-labeled myosin filaments also revealed ca. 10 times better S/N ratio than those obtained with a standard TE(102) cavity. For the side-access DR with sample capillaries oriented either parallel or perpendicular to the external magnetic field, the Q- and filling factors are in good agreement with the theoretical estimates derived from the distribution of magnetic (H(1)) and electric (E(1)) components. PMID:10698655

  2. Intramyocellular lipid dependence on skeletal muscle fiber type and orientation characterized by diffusion tensor imaging and 1H-MRS

    Science.gov (United States)

    Valaparla, Sunil K.; Gao, Feng; Abdul-Ghani, Muhammad; Clarke, Geoffrey D.

    2014-03-01

    When muscle fibers are aligned with the B0 field, intramyocellular lipids (IMCL), important for providing energy during physical activity, can be resolved in proton magnetic resonance spectra (1H-MRS). Various muscles of the leg differ significantly in their proportion of fibers and angular distribution. This study determined the influence of muscle fiber type and orientation on IMCL using 1H-MRS and diffusion tensor imaging (DTI). Muscle fiber orientation relative to B0 was estimated by pennation angle (PA) measurements from DTI, providing orientation-specific extramyocellular lipid (EMCL) chemical shift data that were used for subject-specific IMCL quantification. Vastus lateralis (VL), tibialis anterior (TA) and soleus (SO) muscles of 6 healthy subjects (21-40 yrs) were studied on a Siemens 3T MRI system with a flex 4-channel coil. 1H-MRS were acquired using stimulated echo acquisition mode (STEAM, TR=3s, TE=270ms). DTI was performed using single shot EPI (b=600s/mm2, 30 directions, TR=4.5s, TE=82ms, and ten×5mm slices) with center slice indexed to the MRS voxel. The average PA's measured from ROI analysis of primary eigenvectors were PA=19.46+/-5.43 for unipennate VL, 15.65+/-3.73 for multipennate SO, and 7.04+/-3.34 for bipennate TA. Chemical shift (CS) was calculated using [3cos2θ-1] dependence: 0.17+/-0.02 for VL, 0.18+/-0.01 for SO and 0.19+/-0.004 ppm for TA. IMCL-CH2 concentrations from spectral analysis were 12.77+/-6.3 for VL, 3.07+/-1.63 for SO and 0.27+/-0.08 mmol/kg ww for TA. Small PA's were measured in TA and large CS with clear separation between EMCL and IMCL peaks were observed. Larger variations in PA were measured VL and SO resulting in an increased overlap of the EMCL on IMCL peaks.

  3. Fiber

    Science.gov (United States)

    Diet - fiber; Roughage; Bulk ... Dietary fiber adds bulk to your diet. Because it makes you feel full faster, it can help with ... Elsevier Saunders; 2016:chap 213. National Research Council. ... Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids ( ...

  4. Fiber

    Science.gov (United States)

    Diet - fiber; Roughage; Bulk ... Dietary fiber adds bulk to your diet. Because it makes you feel full faster, it can help with weight control. Fiber aids digestion and helps prevent constipation . It is ...

  5. Force-velocity and power characteristics of rat soleus muscle fibers after hindlimb suspension

    Science.gov (United States)

    Mcdonald, K. S.; Blaser, C. A.; Fitts, R. H.

    1994-01-01

    The effects of 1, 2, and 3 wk of hindlimb suspension (HS) on force-velocity and power characteristics of single rat soleus fibers were determined. After 1, 2, or 3 wk of HA, small fiber bundles were isolated, placed in skinning solution, and stored at -20 C until studied. Single fibers were isolated and placed between a motor arm and force transducer, functional properties were studied, and fiber protein content was subsequently analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Additional fibers were isolated from soleus of control after 1 and 3 wk of HS, and fiber type distribution and myosin light chain stoichiometry were determined from SDS-PAGE analysis. After 1 wk of HS, percent type I fibers declined from 82 to 74%, whereas hybrid fibers increased from 10 to 18%. Percent fast type II fibers increased from 8% in control and 1 wk of HS to 26% by 3 wk of HS. Most fibers showed an increased unloaded maximal shortening velocity (V sub O)), but myosin heavy chain remained entirely slow type I. The mechanism for increased V(sub O) is unknown. There was a progressive decrease in fiber diameter and peak force after 1, 2, and 3 wk of HS, respectively. One week of HS resulted in a shift of the force-velocity curve, and between 2 and 3 wk of HS the curve shifted further such that V(sub O) was higher than control at all relative loads less than 45% peak isometric force. Peak absolute power output of soleus fibers progressively decreased through 2 wk of HS but showed no further change at 3 wk. The results suggest that between 2 and 3 wk the HS-induced alterations in the force-velocity relationship act to maintain the power output of single soleus fibers despite a continued reduction in fiber force.

  6. miR-206 Represses Hypertrophy of Myogenic Cells but Not Muscle Fibers via Inhibition of HDAC4

    OpenAIRE

    Winbanks, Catherine E.; Beyer, Claudia; Hagg, Adam; Qian, Hongwei; Sepulveda, Patricio V.; Gregorevic, Paul

    2013-01-01

    microRNAs regulate the development of myogenic progenitors, and the formation of skeletal muscle fibers. However, the role miRNAs play in controlling the growth and adaptation of post-mitotic musculature is less clear. Here, we show that inhibition of the established pro-myogenic regulator miR-206 can promote hypertrophy and increased protein synthesis in post-mitotic cells of the myogenic lineage. We have previously demonstrated that histone deacetylase 4 (HDAC4) is a target of miR-206 in th...

  7. Differential effects of peroxynitrite on contractile protein properties in fast- and slow-twitch skeletal muscle fibers of rat.

    Science.gov (United States)

    Dutka, T L; Mollica, J P; Lamb, G D

    2011-03-01

    Oxidative modification of contractile proteins is thought to be a key factor in muscle weakness observed in many pathophysiological conditions. In particular, peroxynitrite (ONOO(-)), a potent short-lived oxidant, is a likely candidate responsible for this contractile dysfunction. In this study ONOO(-) or 3-morpholinosydnonimine (Sin-1, a ONOO(-) donor) was applied to rat skinned muscle fibers to characterize the effects on contractile properties. Both ONOO(-) and Sin-1 exposure markedly reduced maximum force in slow-twitch fibers but had much less effect in fast-twitch fibers. The rate of isometric force development was also reduced without change in the number of active cross bridges. Sin-1 exposure caused a disproportionately large decrease in Ca(2+) sensitivity, evidently due to coproduction of superoxide, as it was prevented by Tempol, a superoxide dismutase mimetic. The decline in maximum force with Sin-1 and ONOO(-) treatments could be partially reversed by DTT, provided it was applied before the fiber was activated. Reversal by DTT indicates that the decrease in maximum force was due at least in part to oxidation of cysteine residues. Ascorbate caused similar reversal, further suggesting that the cysteine residues had undergone S-nitrosylation. The reduction in Ca(2+) sensitivity, however, was not reversed by either DTT or ascorbate. Western blot analysis showed cross-linking of myosin heavy chain (MHC) I, appearing as larger protein complexes after ONOO(-) exposure. The findings suggest that ONOO(-) initially decreases maximum force primarily by oxidation of cysteine residues on the myosin heads, and that the accompanying decrease in Ca(2+) sensitivity is likely due to other, less reversible actions of hydroxyl or related radicals. PMID:21030671

  8. Potassium-transporting proteins in skeletal muscle: cellular location and fiber-type differences

    DEFF Research Database (Denmark)

    Kristensen, Michael; Juel, Carsten

    2010-01-01

    Potassium (K+) displacement in skeletal muscle may be an important factor in the development of muscle fatigue during intense exercise. It has been shown in vitro that an increase in the extracellular K+ concentration ([K+]e) to values higher than approx. 10 mm significantly reduce force developm......Potassium (K+) displacement in skeletal muscle may be an important factor in the development of muscle fatigue during intense exercise. It has been shown in vitro that an increase in the extracellular K+ concentration ([K+]e) to values higher than approx. 10 mm significantly reduce force...

  9. Observation on the breeding activity of the shore barnacle chthamalus malayensis pilsbry in Bombay harbor

    Directory of Open Access Journals (Sweden)

    Ashok A. Karande

    1963-01-01

    Full Text Available A prerequisite for rearing larval stages of barnacles which form an important group amongst the fouling organisms is adequate knowledge of the breeding habits and the time and duration of their reproductive phase. Such knowledge is also useful for assessing the results of the field toxicity tests. The present paper gives an account of the breeding behaviour of the shore barnacle, Chthamalus malayensis, which is found in great abundance along the Bombay coast. If the breeding behaviour of Ch. malayensis reported in the paper represents that of other barnacles in Bombay harbor, the seasonal variations in barnacle settlement reported by other workers can be understood.

  10. High-resolution scanning electron-microscopic studies on the three-dimensional structure of mitochondria and sarcoplasmic reticulum in the different twitch muscle fibers of the frog.

    Science.gov (United States)

    Ogata, T; Yamasaki, Y

    1987-12-01

    The three-dimensional structure of the mitochondria and sarcoplasmic reticulum (SR) in the three types of twitch fibers, i.e., the red, white and intermediate skeletal muscle fibers, of the vastus lateralis muscle of the Japanese meadow frog (Rana nigromaculata nigromaculata Hallowell) was examined by high resolution scanning electron microscopy, after removal of the cytoplasmic matrices. The small red fibers have numerous mitochondrial columns of large diameter, while the large white fibers have a small number of mitochondrial columns of small diameter. In the medium-size intermediate fibers, the number and diameter of the mitochondrial columns are intermediate between those of the red and white fibers. In all three types of fibers, the terminal cisternae and transverse tubules form triads at the level of each Z-line. The thick terminal cisternae continue into much thinner flat intermediate cisternae, through a transitional part where a row of tiny indentations can be observed. Numerous slender longitudinal tubules originating from the intermediate cisternae, extend longitudinally or obliquely and form elongated oval networks of various sizes in front of the A-band, then fuse to form the H-band collar (fenestrated collar) around the myofibrils. On the surface of the H-band collar, small fenestrations as well as tiny hollows are seen. The three-dimensional structure of SR is basically the same in all three muscle fiber-types. However, the SR is sparse on the surface of mitochondria, so the mitochondria-rich red fiber has a smaller total volume of SR than the mitochondria-poor white fiber. The volume of SR of the intermediate fiber is intermediate between other the two. PMID:3690630

  11. Muscle spindles exhibit core lesions and extensive degeneration of intrafusal fibers in the Ryr1{sup I4895T/wt} mouse model of core myopathy

    Energy Technology Data Exchange (ETDEWEB)

    Zvaritch, Elena; MacLennan, David H., E-mail: david.maclennan@utoronto.ca

    2015-04-24

    Muscle spindles from the hind limb muscles of adult Ryr1{sup I4895T/wt} (IT/+) mice exhibit severe structural abnormalities. Up to 85% of the spindles are separated from skeletal muscle fascicles by a thick layer of connective tissue. Many intrafusal fibers exhibit degeneration, with Z-line streaming, compaction and collapse of myofibrillar bundles, mitochondrial clumping, nuclear shrinkage and pyknosis. The lesions resemble cores observed in the extrafusal myofibers of this animal model and of core myopathy patients. Spindle abnormalities precede those in extrafusal fibers, indicating that they are a primary pathological feature in this murine Ryr1-related core myopathy. Muscle spindle involvement, if confirmed for human core myopathy patients, would provide an explanation for an array of devastating clinical features characteristic of these diseases and provide novel insights into the pathology of RYR1-related myopathies. - Highlights: • Muscle spindles exhibit structural abnormalities in a mouse model of core myopathy. • Myofibrillar collapse and mitochondrial clumping is observed in intrafusal fibers. • Myofibrillar degeneration follows a pattern similar to core formation in extrafusal myofibers. • Muscle spindle abnormalities are a part of the pathological phenotype in the mouse model of core myopathy. • Direct involvement of muscle spindles in the pathology of human RYR1-related myopathies is proposed.

  12. Muscle spindles exhibit core lesions and extensive degeneration of intrafusal fibers in the Ryr1I4895T/wt mouse model of core myopathy

    International Nuclear Information System (INIS)

    Muscle spindles from the hind limb muscles of adult Ryr1I4895T/wt (IT/+) mice exhibit severe structural abnormalities. Up to 85% of the spindles are separated from skeletal muscle fascicles by a thick layer of connective tissue. Many intrafusal fibers exhibit degeneration, with Z-line streaming, compaction and collapse of myofibrillar bundles, mitochondrial clumping, nuclear shrinkage and pyknosis. The lesions resemble cores observed in the extrafusal myofibers of this animal model and of core myopathy patients. Spindle abnormalities precede those in extrafusal fibers, indicating that they are a primary pathological feature in this murine Ryr1-related core myopathy. Muscle spindle involvement, if confirmed for human core myopathy patients, would provide an explanation for an array of devastating clinical features characteristic of these diseases and provide novel insights into the pathology of RYR1-related myopathies. - Highlights: • Muscle spindles exhibit structural abnormalities in a mouse model of core myopathy. • Myofibrillar collapse and mitochondrial clumping is observed in intrafusal fibers. • Myofibrillar degeneration follows a pattern similar to core formation in extrafusal myofibers. • Muscle spindle abnormalities are a part of the pathological phenotype in the mouse model of core myopathy. • Direct involvement of muscle spindles in the pathology of human RYR1-related myopathies is proposed

  13. 单纤维对训练的适应%Functional and structural plasticity of single human muscle fibers

    Institute of Scientific and Technical Information of China (English)

    FRANCAUX Marc; MALISOUX Laurent; THEISEN Daniel

    2007-01-01

    随着特殊的训练计划被教练员们采用以促进运动员的肌肉适应能力,肌肉训练也成为渐进式康复的重要组成部分,它能阻止与丧失运动能力、老化、疾病或微重力相关的萎缩效应.为了优化不同类型的干扰措施,需要更好地理解运动训练产生的反应,以及识别决定肌肉功能的各种机制.虽然整体肌肉活动在某种程度上是通过适应运动神经元爆发、运动单元补充模式或者肌肉量来进行的,本研究着重探讨肌肉纤维类型的表达以及训练后收缩肌的功能性适应能力.单一无皮纤维被证明是常用的实验模型,用于研究与肌浆球蛋白重链对碘氧基苯甲醚相关的试管内收缩特性.人体纤维主要的功能和生化特性在过去二十年中已经被详细研究了,但近来,无皮纤维模式正被用于研究不同类型的诱发训练后单纤维的功能适应性.本文的目的是概述收缩肌对于特定运动训练计划的反应,以及帮助形成适用于运动科学和康复的训练计划.%While specific training programs are used by trainers to induce particular muscle adaptations in athletes,muscle training is also an important component of progressive rehabilitation to limit the atrophic effect associated with immobilization, ageing, disease or microgravity. To optimize these different types of intervention, a good understanding of the response to exercise training and the identification of the mechanisms that determine muscle function are required. While whole muscle performance can be partly determined by adaptations in the firing rate of motorneurons,the pattern of motor unit recruitments or muscle size,the present review will focus specifically on muscle fiber type expression and the functional adaptations of the contractile apparatus following training. Single skinned fibers have been shown to be a consistent experimental model to be used for the study of contractile characteristics in vitro

  14. Experiment K-6-21. Effect of microgravity on 1) metabolic enzymes of type 1 and type 2 muscle fibers and on 2) metabolic enzymes, neutransmitter amino acids, and neurotransmitter associated enzymes in motor and somatosensory cerebral cortex. Part 1: Metabolic enzymes of individual muscle fibers; part 2: metabolic enzymes of hippocampus and spinal cord

    Science.gov (United States)

    Lowry, O.; Mcdougal, D., Jr.; Nemeth, Patti M.; Maggie, M.-Y. Chi; Pusateri, M.; Carter, J.; Manchester, J.; Norris, Beverly; Krasnov, I.

    1990-01-01

    The individual fibers of any individual muscle vary greatly in enzyme composition, a fact which is obscured when enzyme levels of a whole muscle are measured. The purpose of this study was therefore to assess the changes due to weightless on the enzyme patterns composed by the individual fibers within the flight muscles. In spite of the limitation in numbers of muscles examined, it is apparent that: (1) that the size of individual fibers (i.e., their dry weight) was reduced about a third, (2) that this loss in dry mass was accompanied by changes in the eight enzymes studied, and (3) that these changes were different for the two muscles, and different for the two enzyme groups. In the soleus muscle the absolute amounts of the three enzymes of oxidative metabolism decreased about in proportion to the dry weight loss, so that their concentration in the atrophic fibers was almost unchanged. In contrast, there was little loss among the four enzymes of glycogenolysis - glycolysis so that their concentrations were substantially increased in the atrophic fibers. In the TA muscle, these seven enzymes were affected in just the opposite direction. There appeared to be no absolute loss among the oxidative enzymes, whereas the glycogenolytic enzymes were reduced by nearly half, so that the concentrations of the first metabolic group were increased within the atrophic fibers and the concentrations of the second group were only marginally decreased. The behavior of hexokinase was exceptional in that it did not decrease in absolute terms in either type of muscle and probably increased as much as 50 percent in soleus. Thus, their was a large increase in concentration of this enzyme in the atrophied fibers of both muscles. Another clear-cut finding was the large increase in the range of activities of the glycolytic enzymes among individual fibers of TA muscles. This was due to the emergence of TA fibers with activities for enzymes of this group extending down to levels as low as

  15. De novo synthesis of purine nucleotides in different fiber types of rat skeletal muscle

    International Nuclear Information System (INIS)

    The contribution of de novo purine nucleotide synthesis to nucleotide metabolism in skeletal muscles is not known. The authors have determined rates of de novo synthesis in soleus (slow-twitch red), red gastrocnemius (fast-twitch red), and white gastrocnemius (fast-twitch white) using the perfused rat hindquarter. 14C glycine incorporation into ATP was linear after 1 and 2 hours of perfusion with 0.2 mM added glycine. The intracellular (I) and extracellular (E) specific activity of 14C glycine was determined by HPLC of phenylisothiocyanate derivatives of neutralized PCA extracts. The rates of de novo synthesis when expressed relative to muscle ATP content show slow and fast-twitch red muscles to be similar and about twice as great as fast-twitch white muscles. This could represent a greater turnover of the adenine nucleotide pool in more oxidative red muscle types

  16. What do barnacle larvae feed on ? Implications in biofouling ecology

    Digital Repository Service at National Institute of Oceanography (India)

    Gaonkar, C.; Anil, A.C.

    (Figure 5). Analysis of variance also indicated a significant variation in barnacle recruitment among different sampling months (ANOVA: p≤0.05). DISCUSSION The mode of nutrition in larval forms plays an important role in their capability..., though the larvae raised in the microcosm experienced nutritional stress which was shown by lower ratios of RNA: DNA (Desai & Anil, 2002). This study further indicates their capability to feed on food materials other than diatoms. As the fecal...

  17. Analysis of the Behaviours Mediating Barnacle Cyprid Reversible Adhesion

    OpenAIRE

    Aldred, Nick; Høeg, Jens Thorvald; Maruzzo, Diego; Anthony S. Clare

    2013-01-01

    When exploring immersed surfaces the cypris larvae of barnacles employ a tenacious and rapidly reversible adhesion mechanism to facilitate their characteristic ‘walking’ behaviour. Although of direct relevance to the fields of marine biofouling and bio-inspired adhesive development, the mechanism of temporary adhesion in cyprids remains poorly understood. Cyprids secrete deposits of a proteinaceous substance during surface attachment and these are often visible as ‘footprints’ on previously e...

  18. Carcass Performance, Muscle Fiber, Meat Quality, and Sensory Quality Characteristics of Crossbred Pigs with Different Live Weights.

    Science.gov (United States)

    Choi, Young Min; Oh, Hee Kyung

    2016-01-01

    In order to attain heavier live weight without impairing pork or sensory quality characteristics, carcass performance, muscle fiber, pork quality, and sensory quality characteristics were compared among the heavy weight (HW, average live weight of 130.5 kg), medium weight (MW, average weight of 111.1 kg), and light weight (LW, average weight of 96.3 kg) pigs at time of slaughter. The loin eye area was 1.47 times greater in the HW group compared to the LW group (64.0 and 43.5 cm(2), p0.05). This greater performance by the HW group compared to the LW group can be explained by a greater total number (1,436 vs. 1,188, ×10(3), p0.05), and higher live weights did not influence sensory quality attributes, including tenderness, juiciness, and flavor. Therefore, these findings indicate that increased live weights in this study did not influence the technological and sensory quality characteristics. Moreover, muscles with a higher number of medium or large size fibers tend to exhibit good carcass performance without impairing meat and sensory quality characteristics. PMID:27433110

  19. Carcass Performance, Muscle Fiber, Meat Quality, and Sensory Quality Characteristics of Crossbred Pigs with Different Live Weights

    Science.gov (United States)

    Oh, Hee Kyung

    2016-01-01

    In order to attain heavier live weight without impairing pork or sensory quality characteristics, carcass performance, muscle fiber, pork quality, and sensory quality characteristics were compared among the heavy weight (HW, average live weight of 130.5 kg), medium weight (MW, average weight of 111.1 kg), and light weight (LW, average weight of 96.3 kg) pigs at time of slaughter. The loin eye area was 1.47 times greater in the HW group compared to the LW group (64.0 and 43.5 cm2, p0.05). This greater performance by the HW group compared to the LW group can be explained by a greater total number (1,436 vs. 1,188, ×103, p0.05), and higher live weights did not influence sensory quality attributes, including tenderness, juiciness, and flavor. Therefore, these findings indicate that increased live weights in this study did not influence the technological and sensory quality characteristics. Moreover, muscles with a higher number of medium or large size fibers tend to exhibit good carcass performance without impairing meat and sensory quality characteristics. PMID:27433110

  20. Indirect speculation method for muscle fiber types%肌纤维类型的间接推测方法

    Institute of Scientific and Technical Information of China (English)

    刘瑞莲; 刘富顺

    2012-01-01

    BACKGROUND: Because of easy to cause injury and high cost, the biopsy technique and electromyography image analysis are unsuitable for muscle fiber type determination, respectively. OBJECTIVE: To establish a simple method to calculate the composition percentage of human slow muscle fiber types. METHODS: Totally 180 male students from College of Physical Education, Yichun University were enrolled as subjects. The test subjects underwent electromyography test and some related indicators examination. All the data were regressively analyzed for statistical analysis. The results were spread and verified in students from the College of Physical Education, Guangxi Normal University at the same age. RESULTS AND CONCLUSION: The time for static isometric knee extension, the number of push-ups, 1 500 m run time, and the absolute value of maximal oxygen uptake were closely correlated with electromyography indicators and slow muscle fibers composition. Then, a simple ternary regression equation of composition percentage of slow muscle fibers was calculated using regression analysis and curve analysis male students majored in physical education. The verification of this equation was satisfactory in the male students from the College of Physical Education, Guangxi Normal University at the same age. These findings indicate that this equation can be used to calculate the composition percentage of slow muscle fibers.%背景:肌纤维类型的判定方法中,活检具有损伤性,肌电图图像分析价格较高,在基层选材中不宜操作.目的:建立较为简易的推算人体慢肌纤维类型百分组成的方法.方法:选择180 名宜春学院体育学院在校男大学生为研究对象,测试受试者肌电图图像及一些相关测试指标,对所测试数据进行回归分析法进行统计分析.然后将结果在广西师范大学体育学院相同年龄段在校体育专业男大学生中进行推广验证.结果与结论:相关性分析发现等长静力伸

  1. Muscle-Specific SIRT1 Gain-of-Function Increases Slow-Twitch Fibers and Ameliorates Pathophysiology in a Mouse Model of Duchenne Muscular Dystrophy

    OpenAIRE

    Angeliki Chalkiadaki; Masaki Igarashi; Armiyaw Sebastian Nasamu; Jovana Knezevic; Leonard Guarente

    2014-01-01

    SIRT1 is a metabolic sensor and regulator in various mammalian tissues and functions to counteract metabolic and age-related diseases. Here we generated and analyzed mice that express SIRT1 at high levels specifically in skeletal muscle. We show that SIRT1 transgenic muscle exhibits a fiber shift from fast-to-slow twitch, increased levels of PGC-1α, markers of oxidative metabolism and mitochondrial biogenesis, and decreased expression of the atrophy gene program. To examine whether increased ...

  2. L-arginine Supplementation Protects Exercise Performance and Structural Integrity of Muscle Fibers after a Single Bout of Eccentric Exercise in Rats

    OpenAIRE

    Lomonosova, Yulia N.; Shenkman, Boris S.; Kalamkarov, Grigorii R.; Kostrominova, Tatiana Y.; Tatyana L Nemirovskaya

    2014-01-01

    Eccentric exercise is known to disrupt sarcolemmal integrity and induce damage of skeletal muscle fibers. We hypothesized that L-arginine (L-Arg; nitric oxide synthase (NOS) substrate) supplementation prior to a single bout of eccentric exercise would diminish exercise-induced damage. In addition, we used N-nitro-L-arginine methyl ester hydrochloride (L-NAME; NOS inhibitor) to clarify the role of native NOS activity in the development of exercise-induced muscle damage. Rats were divided into ...

  3. Muscle fiber-type distribution predicts weight gain and unfavorable left ventricular geometry: a 19 year follow-up study

    Directory of Open Access Journals (Sweden)

    Hernelahti Miika

    2006-01-01

    Full Text Available Abstract Background Skeletal muscle consists of type-I (slow-twitch and type-II (fast-twitch fibers, with proportions highly variable between individuals and mostly determined by genetic factors. Cross-sectional studies have associated low percentage of type-I fibers (type-I% with many cardiovascular risk factors. Methods We investigated whether baseline type-I% predicts left ventricular (LV structure and function at 19-year follow-up, and if so, which are the strongest mediating factors. At baseline in 1984 muscle fiber-type distribution (by actomyosin ATPase staining was studied in 63 healthy men (aged 32–58 years. The follow-up in 2003 included echocardiography, measurement of obesity related variables, physical activity and blood pressure. Results In the 40 men not using cardiovascular drugs at follow-up, low type-I% predicted higher heart rate, blood pressure, and LV fractional shortening suggesting increased sympathetic tone. Low type-I% predicted smaller LV chamber diameters (P ≤ 0.009 and greater relative wall thickness (P = 0.034 without increase in LV mass (concentric remodeling. This was explained by the association of type-I% with obesity related variables. Type-I% was an independent predictor of follow-up body fat percentage, waist/hip ratio, weight gain in adulthood, and physical activity (in all P ≤ 0.001. After including these risk factors in the regression models, weight gain was the strongest predictor of LV geometry explaining 64% of the variation in LV end-diastolic diameter, 72% in end-systolic diameter, and 53% in relative wall thickness. Conclusion Low type-I% predicts obesity and weight gain especially in the mid-abdomen, and consequently unfavourable LV geometry indicating increased cardiovascular risk.

  4. Regeneration of skeletal muscle fibers from autologous satellite cells multiplied in vitro. An experimental model for testing cultured cell myogenicity

    International Nuclear Information System (INIS)

    An experimental model used to test in vivo myogenicity of autologous satellite cells multiplied in vitro is described. Free muscle autotransplantation served as the basis and was combined with x-irradiation. Administration of 1500, 2500, and 3500 rad doses 24 hours before or after ischemia showed that inhibition of spontaneous regeneration is dose dependent and more efficient when irradiation was applied before injury. A single dose of 2500 rad before injury resulted in the formation of a cystic structure ideal for cell implantation. FITC-latex beads and/or carbocyanine dyes were internalized by mononucleated satellite cells in vitro. Labeling did not affect survival or development of these cells. No sign of marker release or spreading from labeled to unlabeled cells was detectable unless by the fusion process. These labels were retained for several weeks. Grafting of labeled dense cellular suspensions into x-irradiated ischemic muscles indicated that satellite cells retain their myogenic characteristic and are able to reform fully differentiated muscle fibers. 55 references

  5. Differences between white and red muscle fibers diameter in three salmon fish species

    OpenAIRE

    Karahmet E.; Vileš A.; Katica A.; Mlaćo N.; Toroman A.

    2014-01-01

    Because of skeletal muscle is the main contributor to body weight in most fish, it is probable that the species of the fish is limited by the growth of this tissue. Several aspects of both somatic size and skeletal muscle growth was investigated in this research work included a total of 20 brown trout (Salmo truta m. fario Lineus), 20 brook trout (Salvelinus alpinus) and 20 rainbow trout (Oncorynchus mykkis Walbaum), the average weight of 200 grams. Gathere...

  6. Size and metabolic properties of single muscle fibers in rat soleus after hindlimb suspension

    Science.gov (United States)

    Hauschka, Edward O.; Roy, Roland R.; Edgerton, V. Reggie

    1987-01-01

    The effect of 28-day-long hind-limb suspension (HS) combined with 10 daily forceful lengthening contractions of the limb on the morphological and metabolic properties of individual fibers of the soleus was studied in rats, using quantitative histochemical techniques. Compared with nonsuspended controls (CON), soleus wet weights of HS rats were decreased by 49 percent; the fibers staining lightly for myosin ATPase ('light-ATPase' fibers) atrophied more than the 'dark-ATPase' fibers. Single-fiber alpha-glycerophosphate dehydrogenase (GPD) and succinate dehydrogenase (SDH) activities were higher in HS than in CON rats. Daily forceful lengthening contractions did not prevent the HS-induced changes. The results support the view that the soleus fibers can change from a slow-twitch oxidative to a fast-twitch oxidative-glycolytic profile, but rarely to a fast-twitch glycolytic one, and that the SDH and GPD activities per volume of tissue can be increased even when there are severe losses of contractile proteins.

  7. Inhibition of myosatellite cell proliferation by gamma irradiation does not prevent the age-related increase of the number of dystrophin-positive fibers in soleus muscles of mdx female heterozygote mice.

    OpenAIRE

    Weller, B; Karpati, G.; Lehnert, S.; Carpenter, S.; Ajdukovic, B.; Holland, P

    1991-01-01

    In skeletal muscles of young mdx female heterozygote mice, there is a mosaic of dystrophin-positive and dystrophin-negative fiber segments. In older animals, there is a marked decline in the number of dystrophin-negative fiber segments. This phenomenon might be due to a fusion of dystrophin-competent satellite cells into the originally dystrophin-negative fiber segments during growth. To study this possibility, soleus muscles of 10-day-old mdx female heterozygotes were gamma irradiated (2000 ...

  8. Glycolytic-to-oxidative fiber-type switch and mTOR signaling activation are early-onset features of SBMA muscle modified by high-fat diet.

    Science.gov (United States)

    Rocchi, Anna; Milioto, Carmelo; Parodi, Sara; Armirotti, Andrea; Borgia, Doriana; Pellegrini, Matteo; Urciuolo, Anna; Molon, Sibilla; Morbidoni, Valeria; Marabita, Manuela; Romanello, Vanina; Gatto, Pamela; Blaauw, Bert; Bonaldo, Paolo; Sambataro, Fabio; Robins, Diane M; Lieberman, Andrew P; Sorarù, Gianni; Vergani, Lodovica; Sandri, Marco; Pennuto, Maria

    2016-07-01

    Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by the expansion of a polyglutamine tract in the androgen receptor (AR). The mechanism by which expansion of polyglutamine in AR causes muscle atrophy is unknown. Here, we investigated pathological pathways underlying muscle atrophy in SBMA knock-in mice and patients. We show that glycolytic muscles were more severely affected than oxidative muscles in SBMA knock-in mice. Muscle atrophy was associated with early-onset, progressive glycolytic-to-oxidative fiber-type switch. Whole genome microarray and untargeted lipidomic analyses revealed enhanced lipid metabolism and impaired glycolysis selectively in muscle. These metabolic changes occurred before denervation and were associated with a concurrent enhancement of mechanistic target of rapamycin (mTOR) signaling, which induced peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC1α) expression. At later stages of disease, we detected mitochondrial membrane depolarization, enhanced transcription factor EB (TFEB) expression and autophagy, and mTOR-induced protein synthesis. Several of these abnormalities were detected in the muscle of SBMA patients. Feeding knock-in mice a high-fat diet (HFD) restored mTOR activation, decreased the expression of PGC1α, TFEB, and genes involved in oxidative metabolism, reduced mitochondrial abnormalities, ameliorated muscle pathology, and extended survival. These findings show early-onset and intrinsic metabolic alterations in SBMA muscle and link lipid/glucose metabolism to pathogenesis. Moreover, our results highlight an HFD regime as a promising approach to support SBMA patients. PMID:26971100

  9. The influence of temperature on the distribution and intensity of the reaction product in rat muscle fibers obtained with the histochemical method for myosin ATPase

    DEFF Research Database (Denmark)

    Kirkeby, S; Tuxen, A

    1989-01-01

    was raised and in others was depressed by alteration of the incubation temperature. There was no obvious correlation between the temperature sensitivity of ATPase in the muscle fibers and their activity for succinic dehydrogenase. It is proposed that the histochemical method for myosin ATPase can be...

  10. Na+,K+-ATPase Na+ affinity in rat skeletal muscle fiber types

    DEFF Research Database (Denmark)

    Kristensen, Michael; Juel, Carsten

    2010-01-01

    Previous studies in expression systems have found different ion activation of the Na(+)/K(+)-ATPase isozymes, which suggest that different muscles have different ion affinities. The rate of ATP hydrolysis was used to quantify Na(+),K(+)-ATPase activity, and the Na(+) affinity of Na(+),K(+)-ATPase......Previous studies in expression systems have found different ion activation of the Na(+)/K(+)-ATPase isozymes, which suggest that different muscles have different ion affinities. The rate of ATP hydrolysis was used to quantify Na(+),K(+)-ATPase activity, and the Na(+) affinity of Na...

  11. Insulin-Dependent H2O2 Production Is Higher in Muscle Fibers of Mice Fed with a High-Fat Diet

    Directory of Open Access Journals (Sweden)

    Ariel Contreras-Ferrat

    2013-07-01

    Full Text Available Insulin resistance is defined as a reduced ability of insulin to stimulate glucose utilization. C57BL/6 mice fed with a high-fat diet (HFD are a model of insulin resistance. In skeletal muscle, hydrogen peroxide (H2O2 produced by NADPH oxidase 2 (NOX2 is involved in signaling pathways triggered by insulin. We evaluated oxidative status in skeletal muscle fibers from insulin-resistant and control mice by determining H2O2 generation (HyPer probe, reduced-to-oxidized glutathione ratio and NOX2 expression. After eight weeks of HFD, insulin-dependent glucose uptake was impaired in skeletal muscle fibers when compared with control muscle fibers. Insulin-resistant mice showed increased insulin-stimulated H2O2 release and decreased reduced-to-oxidized glutathione ratio (GSH/GSSG. In addition, p47phox and gp91phox (NOX2 subunits mRNA levels were also high (~3-fold in HFD mice compared to controls, while protein levels were 6.8- and 1.6-fold higher, respectively. Using apocynin (NOX2 inhibitor during the HFD feeding period, the oxidative intracellular environment was diminished and skeletal muscle insulin-dependent glucose uptake restored. Our results indicate that insulin-resistant mice have increased H2O2 release upon insulin stimulation when compared with control animals, which appears to be mediated by an increase in NOX2 expression.

  12. Effects of variation in porcine MYOD1 gene on muscle fiber characteristics, lean meat production, and meat quality traits.

    Science.gov (United States)

    Lee, E A; Kim, J M; Lim, K S; Ryu, Y C; Jeon, W M; Hong, K C

    2012-09-01

    Three single nucleotide polymorphisms (SNPs) in the porcine MYOD1 gene were used for association analysis and haplotype construction to evaluate the effects of their substitution. Four hundred and three pigs of Yorkshire and Berkshire breeds were used. The mRNA expression levels of MYOD1 were examined. The g.489C>T and g.1264C>A SNPs were significantly associated with several muscle fiber characteristics, the loin eye area, and lightness. Particularly, animals having hetero-genotypes of both sites showed good performance both in lean meat production and meat quality traits. The results of haplotype substitution were similar to the associations of individual SNPs. Moreover, the 2 SNPs had significant effects on mRNA expression. Therefore, the g.489C>T and g.1264C>A SNPs in MYOD1 may be meaningful DNA markers that can be used for improving important porcine economic traits. PMID:22554470

  13. Effect of acute and chronic eccentric exercise on FOXO1 mRNA expression as fiber type transition factor in rat skeletal muscles.

    Science.gov (United States)

    Azad, Milad; Khaledi, Neda; Hedayati, Mehdi

    2016-06-15

    Skeletal muscle is a highly elastic tissue which can respond to various functional demands by altering fiber-type composition. Exercise affects muscle fiber phenotype. One of the transcription factors that induce fiber-type transition is forkhead box O1 (FOXO1). Since eccentric contraction considered an essential part of exercise, so we are interested to see the effects of eccentric exercise (acute/chronic) on FOXO1 as an important factor of fiber-type transition in rat skeletal muscles. Twenty-four Sprague-Dawley rats (190-235g) were divided to 3 groups of 8 rats: 1) chronic eccentric exercise (CEE), 2) acute eccentric exercise (AEE), and 3) control (C). The exercise groups underwent downhill running protocol. CEE was running on treadmill in 3days of week for 9weeks, that slope and duration gradually managed from -4° to -16° and 15 to 90min, respectively. AEE group was running with 16m/min on -16° slope for 3 consecutive days that included 18 sets of 5min with rest interval of 2min in between. Soleus and super vastus lateralis (SVL) muscles mRNA were analyzed by real-time RT-PCR. SVL FOXO1 mRNA levels increased by 3.92-fold in the AEE and decreased 0.56-fold in the CEE group and were not significant in soleus muscle. In soleus muscle, myosin heavy chain (MHC) IIa, IIx, and IIb decreased in the AEE group and MHC IIa and IIx decreased in the CEE group. In SVL muscle, MHC I, IIa, and IIx increased in the AEE group and MHC IIa and IIX increased in the CEE group. In summary, both acute and chronic eccentric exercise could lead to change in FOXO1 mRNA only in fast SVL muscle of rat and so could induce fiber-type transition in both muscles regardless of changes in expression of FOXO1. So, oxidative stress can play important role in change of FOXO1. PMID:26915490

  14. Severe insulin-resistant diabetes mellitus in patients with congenital muscle fiber type disproportion myopathy

    DEFF Research Database (Denmark)

    Vestergaard, H; Klein, H H; Hansen, T;

    1995-01-01

    . Insulin receptor function and glycogen synthase (GS) activity and expression were examined in biopsies of vastus lateralis muscle. Despite a 45-90-fold increase in both fasting and postprandial serum insulin levels, both CFTDM patients had diabetes mellitus. Clamp studies revealed that the oldest boy had...

  15. FES Training in Aging: interim results show statistically significant improvements in mobility and muscle fiber size

    Directory of Open Access Journals (Sweden)

    Helmut Kern

    2012-03-01

    Full Text Available Aging is a multifactorial process that is characterized by decline in muscle mass and performance. Several factors, including reduced exercise, poor nutrition and modified hormonal metabolism, are responsible for changes in the rates of protein synthesis and degradation that drive skeletal muscle mass reduction with a consequent decline of force generation and mobility functional performances. Seniors with normal life style were enrolled: two groups in Vienna (n=32 and two groups in Bratislava: (n=19. All subjects were healthy and declared not to have any specific physical/disease problems. The two Vienna groups of seniors exercised for 10 weeks with two different types of training (leg press at the hospital or home-based functional electrical stimulation, h-b FES. Demografic data (age, height and weight were recorded before and after the training period and before and after the training period the patients were submitted to mobility functional analyses and muscle biopsies. The mobility functional analyses were: 1. gait speed (10m test fastest speed, in m/s; 2. time which the subject needed to rise from a chair for five times (5x Chair-Rise, in s; 3. Timed –Up-Go- Test, in s; 4. Stair-Test, in s; 5. isometric measurement of quadriceps force (Torque/kg, in Nm/kg; and 6. Dynamic Balance in mm. Preliminary analyses of muscle biopsies from quadriceps in some of the Vienna and Bratislava patients present morphometric results consistent with their functional behaviors. The statistically significant improvements in functional testings here reported demonstrates the effectiveness of h-b FES, and strongly support h-b FES, as a safe home-based method to improve contractility and performances of ageing muscles.

  16. Muscle fibers inside a fat tumor: A non-specific imaging finding of benignancy

    Energy Technology Data Exchange (ETDEWEB)

    Donato, M. [Department of Anatomical Pathology Hospital Dr. R.A Calderon Guardia, Universidad De Costa Rica, P.O. Box 6098-1000, San Jose (Costa Rica); Formation Scholarship of Instituto Costarricense Contra El Cancer, Fellowship Musculoskeletal Anatomical Pathology Department, Istituto Ortopedico Rizzoli, Bologna (Italy); Vanel, D. [Radiology, Musculoskeletal Oncology Research Center, Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna (Italy); Alberghini, M. [Surgical pathology, Musculoskeletal Anatomical Pathology Department, Istituto Ortopedico Rizzoli, Bologna, Italy, Via di Barbiano 1/10, 40136 Bologna (Italy)], E-mail: marcoalberghini@ior.it; Mercuri, M. [Oncology orthopaedic surgery, Musculoskeletal Oncology Department, Istituto Ortopedico Rizzoli, Via Pupuli 1, 40136 Bologna (Italy)

    2009-10-15

    Introduction: The differential diagnosis between benign and low-grade well-differentiated malignant lipomatous tumors might be very difficult for both the radiologist and the pathologist, although it has practical consequences. Among the criteria, muscular fibers detected inside the lesion are considered radiologically and histologically as a reliable sign of a benign intramuscular lipoma. New genetic criteria are now available. We report two cases of fat tumors containing muscular fibers both radiologically and histologically, but which are definitely malignant, considering genetic criteria. Material and methods: Two cases of soft tissue fat tumors, containing muscular fibers on imaging examinations as well as histologically, had an aggressive behaviour, suggesting malignancy. Genetic criteria were therefore used to confirm the clinical impression. Results: MDM2 and CDK4 confirmed the malignancy in the two cases. Conclusion: Intra lesional muscular fibers detected on imaging or histological examinations should not be considered as a completely reliable sign of a benign intramuscular lipoma. In case of atypical clinical behaviour, genetic criteria should be used to prove the aggressiveness of the tumor.

  17. Four days of muscle disuse impairs single fiber contractile function in young and old healthy men

    DEFF Research Database (Denmark)

    Hvid, Lars Grøndahl; Suetta, Charlotte Arneboe; Aagaard, Per;

    2013-01-01

    The purpose of the study was to investigate the effects of 4 days of disuse (knee brace) on contractile function of isolated vastus lateralis fibers (n=486) from 11 young (24.3+/-0.9 yrs) and 11 old (67.2+/-1.0 yrs) healthy men having comparable levels of physical activity. Prior to disuse single...

  18. Muscle fibers inside a fat tumor: A non-specific imaging finding of benignancy

    International Nuclear Information System (INIS)

    Introduction: The differential diagnosis between benign and low-grade well-differentiated malignant lipomatous tumors might be very difficult for both the radiologist and the pathologist, although it has practical consequences. Among the criteria, muscular fibers detected inside the lesion are considered radiologically and histologically as a reliable sign of a benign intramuscular lipoma. New genetic criteria are now available. We report two cases of fat tumors containing muscular fibers both radiologically and histologically, but which are definitely malignant, considering genetic criteria. Material and methods: Two cases of soft tissue fat tumors, containing muscular fibers on imaging examinations as well as histologically, had an aggressive behaviour, suggesting malignancy. Genetic criteria were therefore used to confirm the clinical impression. Results: MDM2 and CDK4 confirmed the malignancy in the two cases. Conclusion: Intra lesional muscular fibers detected on imaging or histological examinations should not be considered as a completely reliable sign of a benign intramuscular lipoma. In case of atypical clinical behaviour, genetic criteria should be used to prove the aggressiveness of the tumor.

  19. Mitochondrial evolution across lineages of the vampire barnacle Notochthamalus scabrosus.

    Science.gov (United States)

    Wares, John P

    2015-02-01

    Eight whole mitochondrial genomes from the barnacle Notochthamalus scabrosus, with one from the northern lineage and seven from the divergent southern lineage, are presented. The annotated and aligned data were analyzed for signals of non-neutral evolution. Overall, these data are consistent with purifying selection operating on the protein-coding regions of the mitochondrion. However, a notable region of nonsynonymous substitution at the 3' end of the ND2 gene region, along with unusual site frequency spectra in two other gene regions, was identified. PMID:24047186

  20. Gene expression changes of single skeletal muscle fibers in response to modulation of the mitochondrial calcium uniporter (MCU

    Directory of Open Access Journals (Sweden)

    Francesco Chemello

    2015-09-01

    Full Text Available The mitochondrial calcium uniporter (MCU gene codifies for the inner mitochondrial membrane (IMM channel responsible for mitochondrial Ca2+ uptake. Cytosolic Ca2+ transients are involved in sarcomere contraction through cycles of release and storage in the sarcoplasmic reticulum. In addition cytosolic Ca2+ regulates various signaling cascades that eventually lead to gene expression reprogramming. Mitochondria are strategically placed in close contact with the ER/SR, thus cytosolic Ca2+ transients elicit large increases in the [Ca2+] of the mitochondrial matrix ([Ca2+]mt. Mitochondrial Ca2+ uptake regulates energy production and cell survival. In addition, we recently showed that MCU-dependent mitochondrial Ca2+ uptake controls skeletal muscle trophism. In the same report, we dissected the effects of MCU-dependent mitochondrial Ca2+ uptake on gene expression through microarray gene expression analysis upon modulation of MCU expression by in vivo AAV infection. Analyses were performed on single skeletal muscle fibers at two time points (7 and 14 days post-AAV injection. Raw and normalized data are available on the GEO database (http://www.ncbi.nlm.nih.gov/geo/ (GSE60931.

  1. Fast-twitch skeletal muscle fiber adaptation to SERCA1 deficiency in a Dutch Improved Red and White calf pseudomyotonia case.

    Science.gov (United States)

    Dorotea, Tiziano; Grünberg, Walter; Murgiano, Leonardo; Plattet, Philippe; Drögemüller, Cord; Mascarello, Francesco; Sacchetto, Roberta

    2015-11-01

    Missense mutations in ATP2A1 gene, encoding SERCA1 protein, cause a muscle disorder designed as congenital pseudomyotonia (PMT) in Chianina and Romagnola cattle or congenital muscular dystonia1 (CMD1) in Belgian Blue cattle. Although PMT is not life-threatening, CMD1 affected calves usually die within a few weeks of age as a result of respiratory complication. We have recently described a muscular disorder in a double muscle Dutch Improved Red and White cross-breed calf. Mutation analysis revealed an ATP2A1 mutation identical to that described in CMD1, even though clinical phenotype was quite similar to that of PMT. Here, we provide evidence for a deficiency of mutated SERCA1 in PMT affected muscles of Dutch Improved Red and White calf, but not of its mRNA. The reduced expression of SERCA1 is selective and not compensated by the SERCA2 isoform. By contrast, pathological muscles are characterized by a broad distribution of mitochondrial markers in all fiber types, not related to intrinsic features of double muscle phenotype and by an increased expression of sarcolemmal calcium extrusion pump. Calcium removal mechanisms, operating in muscle fibers as compensatory response aimed at lowering excessive cytoplasmic calcium concentration caused by SERCA1 deficiency, could explain the difference in severity of clinical signs. PMID:26482047

  2. Scanning electron-microscopic studies on the three-dimensional structure of mitochondria in the mammalian red, white and intermediate muscle fibers.

    Science.gov (United States)

    Ogata, T; Yamasaki, Y

    1985-01-01

    The three-dimensional structure and arrangement of mitochondria in the red, white and intermediate striated muscle fibers of the rat were examined under a field-emission type scanning electron microscope after removal of cytoplasmic matrices by means of the Osmium-DMSO-Osmium procedure. Beneath the sarcolemma, spherical or ovoid subsarcolemmal mitochondria show accumulations. The mitochondria are numerous and large in size in the red fibers, intermediate in the intermediate fibers, and few and small in the white fibers. Paired, slender I-band-limited mitochondria were located on both sides of the Z-line and partly embraced the myofibrils at the I-band level; they occurred in all three types of fibers. In the intermyofibrillar spaces, numerous mitochondria formed mitochondrial columns. These columns were classified into two types: 1) thick mitochondrial columns, formed by multiple mitochondria each with an intermyofibrillar space corresponding to one sarcomere in length, and 2) thin mitochondrial columns, established by single mitochondria corresponding to one sarcomere in length. In the red fibers mitochondrial columns were abundant and the ratio of the thick and thin columns was almost the same, while in the intermediate fibers most of the columns belonged to the thin type. The white fibers displayed rare, very thin columns. PMID:4028126

  3. On the origin of a novel parasitic-feeding mode within suspension-feeding barnacles.

    Science.gov (United States)

    Rees, David John; Noever, Christoph; Høeg, Jens Thorvald; Ommundsen, Anders; Glenner, Henrik

    2014-06-16

    In his monograph on Cirripedia from 1851, Darwin pointed to a highly unusual, plateless, and most likely parasitic barnacle of uncertain phylogenetic affinity. Darwin's barnacle was Anelasma squalicola, found on deep-water sharks of the family Etmopteridae, or lantern sharks. The barnacle is uncommon and is therefore rarely studied. Recent observations by us have shown that they occur at an unusually high prevalence on the velvet belly lantern shark, Etmopterus spinax, in restricted fjord areas of western Norway. A phylogenetic analysis based on ribosomal DNA data (16S, 18S, and 28S) from 99 selected barnacle species, including all available pedunculate barnacle sequences from GenBank, shows that A. squalicola is most closely related (sister taxon) to the pedunculate barnacle Capitulum mitella. Both C. mitella and species of Pollicipes, situated one node higher in the tree, are conventional suspension feeders from the rocky intertidal. Our phylogenetic analysis now makes it possible to establish morphological homologies between A. squalicola and its sister taxon and provides the evolutionary framework to explain the unprecedented transition from a filter-feeding barnacle to a parasitic mode of life. PMID:24909326

  4. Differentiation of the intracellular structure of slow- versus fast-twitch muscle fibers through evaluation of the dielectric properties of tissue

    International Nuclear Information System (INIS)

    Slow-twitch (type 1) skeletal muscle fibers have markedly greater mitochondrial content than fast-twitch (type 2) fibers. Accordingly, we sought to determine whether the dielectric properties of these two fiber types differed, consistent with their distinct intracellular morphologies. The longitudinal and transverse dielectric spectrum of the ex vivo rat soleus (a predominantly type 1 muscle) and the superficial layers of rat gastrocnemius (predominantly type 2) (n = 15) were measured in the 1 kHz–10 MHz frequency range and modeled to a resistivity Cole–Cole function. Major differences were especially apparent in the dielectric spectrum in the 1 to 10 MHz range. Specifically, the gastrocnemius demonstrated a well-defined, higher center frequency than the soleus muscle, whereas the soleus muscle showed a greater difference in the modeled zero and infinite resistivities than the gastrocnemius. These findings are consistent with the fact that soleus tissue has larger and more numerous mitochondria than gastrocnemius. Evaluation of tissue at high frequency could provide a novel approach for assessing intracellular structure in health and disease. (paper)

  5. Differentiation of the intracellular structure of slow- versus fast-twitch muscle fibers through evaluation of the dielectric properties of tissue

    Science.gov (United States)

    Sanchez, B.; Li, J.; Bragos, R.; Rutkove, S. B.

    2014-05-01

    Slow-twitch (type 1) skeletal muscle fibers have markedly greater mitochondrial content than fast-twitch (type 2) fibers. Accordingly, we sought to determine whether the dielectric properties of these two fiber types differed, consistent with their distinct intracellular morphologies. The longitudinal and transverse dielectric spectrum of the ex vivo rat soleus (a predominantly type 1 muscle) and the superficial layers of rat gastrocnemius (predominantly type 2) (n = 15) were measured in the 1 kHz-10 MHz frequency range and modeled to a resistivity Cole-Cole function. Major differences were especially apparent in the dielectric spectrum in the 1 to 10 MHz range. Specifically, the gastrocnemius demonstrated a well-defined, higher center frequency than the soleus muscle, whereas the soleus muscle showed a greater difference in the modeled zero and infinite resistivities than the gastrocnemius. These findings are consistent with the fact that soleus tissue has larger and more numerous mitochondria than gastrocnemius. Evaluation of tissue at high frequency could provide a novel approach for assessing intracellular structure in health and disease.

  6. How do coral barnacles start their life in their hosts?

    Science.gov (United States)

    Liu, Jennie Chien Wen; Høeg, Jens Thorvald; Chan, Benny K K

    2016-06-01

    Coral-associated invertebrates are the most significant contributors to the diversity of reef ecosystems, but no studies have examined how larvae manage to settle and grow in their coral hosts. Video recordings were used to document this process in the coral barnacle Darwiniella angularis associated with the coral Cyphastrea chalcidicum Settlement and metamorphosis in feeding juveniles lasted 8-11 days and comprised six phases. The settling cyprid starts by poking its antennules into the tissue of the prospective host (I: probing stage). The coral releases digestive filaments for defence, but tolerating such attack the cyprid penetrates further (II: battling stage). Ecdysis is completed 2 days after settlement (III: carapace detachment). The barnacle becomes embedded deep in the coral tissue while completing metamorphosis between 4 and 6 days (IV: embedding stage), but reappears as a feeding juvenile 8-11 days after settlement (V: emerging stage; VI: feeding stage). Cyprids preferably settle in areas between the coral polyps, where they have a much higher survival rate than on the polyp surfaces. PMID:27330170

  7. Muscle Loss in Elderly

    OpenAIRE

    Nikolić, Marina; Šoić Vranić, Tamara; Arbanas, Juraj; Cvijanović, Olga; Bajek, Snježana

    2010-01-01

    Aging is associated with loss of skeletal muscle mass, strength and endurance. The aim of this study was to determinate age related changes in human muscles with different function and location in the body (vastus lateralis muscle and intercostal internus muscle). Our results suggest that age related muscle atrophy affect both human skeletal muscles. Also, the results showed the increase in percentage of muscle fibers with high oxidative activity during aging.

  8. The Na conductance in the sarcolemma and the transverse tubular system membranes of mammalian skeletal muscle fibers.

    Science.gov (United States)

    DiFranco, Marino; Vergara, Julio L

    2011-10-01

    Na (and Li) currents and fluorescence transients were recorded simultaneously under voltage-clamp conditions from mouse flexor digitorum brevis fibers stained with the potentiometric dye di-8-ANEPPS to investigate the distribution of Na channels between the surface and transverse tubular system (TTS) membranes. In fibers rendered electrically passive, voltage pulses resulted in step-like fluorescence changes that were used to calibrate the dye response. The effects of Na channel activation on the TTS voltage were investigated using Li, instead of Na, because di-8-ANEPPS transients show anomalies in the presence of the latter. Na and Li inward currents (I(Na), I(Li); using half of the physiological ion concentration) showed very steep voltage dependences, with no reversal for depolarizations beyond the calculated equilibrium potential, suggesting that most of the current originates from a noncontrolled membrane compartment. Maximum peak I(Li) was ∼ 30% smaller than for I(Na), suggesting a Li-blocking effect. I(Li) activation resulted in the appearance of overshoots in otherwise step-like di-8-ANEPPS transients. Overshoots had comparable durations and voltage dependence as those of I(Li). Simultaneously measured maximal overshoot and peak I(Li) were 54 ± 5% and 773 ± 53 µA/cm(2), respectively. Radial cable model simulations predicted the properties of I(Li) and di-8-ANEPPS transients when TTS access resistances of 10-20 Ω cm(2), and TTS-to-surface Na permeability density ratios in the range of 40:60 to 70:30, were used. Formamide-based osmotic shock resulted in incomplete detubulation. However, results from a subpopulation of treated fibers (low capacitance) provide confirmatory evidence that a significant proportion of I(Li), and the overshoot in the optical signals, arises from the TTS in normal fibers. The quantitative evaluation of the distribution of Na channels between the sarcolemma and the TTS membranes, as provided here, is crucial for the

  9. Aged Muscle Demonstrates Fiber-Type Adaptations in Response to Mechanical Overload, in the Absence of Myofiber Hypertrophy, Independent of Satellite Cell Abundance.

    Science.gov (United States)

    Lee, Jonah D; Fry, Christopher S; Mula, Jyothi; Kirby, Tyler J; Jackson, Janna R; Liu, Fujun; Yang, Lin; Dupont-Versteegden, Esther E; McCarthy, John J; Peterson, Charlotte A

    2016-04-01

    Although sarcopenia, age-associated loss of muscle mass and strength, is neither accelerated nor exacerbated by depletion of muscle stem cells, satellite cells, we hypothesized that adaptation in sarcopenic muscle would be compromised. To test this hypothesis, we depleted satellite cells with tamoxifen treatment of Pax7(CreER)-DTA mice at 4 months of age, and 20 months later subjected the plantaris muscle to 2 weeks of mechanical overload. We found myofiber hypertrophy was impaired in aged mice regardless of satellite cell content. Even in the absence of growth, vehicle-treated mice mounted a regenerative response, not apparent in tamoxifen-treated mice. Further, myonuclear accretion occurred in the absence of growth, which was prevented by satellite cell depletion, demonstrating that myonuclear addition is insufficient to drive myofiber hypertrophy. Satellite cell depletion increased extracellular matrix content of aged muscle that was exacerbated by overload, potentially limiting myofiber growth. These results support the idea that satellite cells regulate the muscle environment, and that their loss during aging may contribute to fibrosis, particularly during periods of remodeling. Overload induced a fiber-type composition improvement, independent of satellite cells, suggesting that aged muscle is very responsive to exercise-induced enhancement in oxidative capacity, even with an impaired hypertrophic response. PMID:25878030

  10. Effects of acute exposure of heavy ion to spinal cord on the properties of motoneurons and muscle fibers in rats. The 2nd report

    International Nuclear Information System (INIS)

    We examined the effects of acute exposure of heavy ion on the properties of motoneurons and their innervating muscle fibers. A 40 Gy dose of heavy ion was applied to the lumbar 4th to 6th segments of the spinal cord in five 8-week-old male rats. Five male rats served as controls. Both the control and heavy-ion-exposed rats were sacrificed one month after exposure to heavy ion. The number, cell body size, and oxidative enzyme activity of motoneurons innervating the soleus and plantaris muscles were analyzed. In addition, cell size, oxidative enzyme activity, and expression of myosin heavy chain isoforms in the soleus and plantaris muscles were analyzed. There were no changes in the number of motoneurons between the control and heavy-ion-exposed rats. On the other hand, cell body sizes were decreased and oxidative enzyme activities were disappeared in motoneurons of the heavy-ion-exposed rats. There were no changes in the cell size, oxidative enzyme activity, or expression of myosin heavy chain isoforms of the muscles between the control and heavy-ion-exposed rats. It is concluded that a 40 Gy dose of heavy ion affects the properties of spinal motoneurons, although there were no influences on the properties of muscle fibers which they innervate. (author)

  11. ROS-Mediated Decline in Maximum Ca2+-Activated Force in Rat Skeletal Muscle Fibers following In Vitro and In Vivo Stimulation

    OpenAIRE

    Dutka, Travis L.; Verburg, Esther; Larkins, Noni; Hortemo, Kristin H.; Lunde, Per K.; Sejersted, Ole M; Lamb, Graham D.

    2012-01-01

    We hypothesised that normal skeletal muscle stimulated intensely either in vitro or in situ would exhibit reactive oxygen species (ROS)-mediated contractile apparatus changes common to many pathophysiological conditions. Isolated soleus (SOL) and extensor digitorum longus (EDL) muscles of the rat were bubbled with 95% O2 and stimulated in vitro at 31°C to give isometric tetani (50 Hz for 0.5 s every 2 s) until maximum force declined to ≤30%. Skinned superficial slow-twitch fibers from the SOL...

  12. Individual, age and sex differences in fiber type composition of slow and fast muscles of adult Lewis rats: comparison with other rat strains

    Czech Academy of Sciences Publication Activity Database

    Novák, Petr; Zachařová, Gisela; Soukup, Tomáš

    2010-01-01

    Roč. 59, č. 5 (2010), s. 783-801. ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LC554; GA ČR(CZ) GA304/08/0256; GA ČR GA305/09/1228 Grant ostatní: EC(XE) LSH-CT-2001-511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : mATPase and muscle fiber types * fiber type composition * inter-strain, individual, age and sex differences Subject RIV: ED - Physiology Impact factor: 1.646, year: 2010

  13. In vivo and in situ synchrotron radiation-based μ-XRF reveals elemental distributions during the early attachment phase of barnacle larvae and juvenile barnacles.

    Science.gov (United States)

    Senkbeil, Tobias; Mohamed, Tawheed; Simon, Rolf; Batchelor, David; Di Fino, Alessio; Aldred, Nick; Clare, Anthony S; Rosenhahn, Axel

    2016-02-01

    Barnacles are able to establish stable surface contacts and adhere underwater. While the composition of adult barnacle cement has been intensively studied, far less is known about the composition of the cement of the settlement-stage cypris larva. The main challenge in studying the adhesives used by these larvae is the small quantity of material available for analysis, being on the order of nanograms. In this work, we applied, for the first time, synchrotron radiation-based μ-X-ray fluorescence analysis (SR-μ-XRF) for in vivo and in situ analysis of young barnacles and barnacle cyprids. To obtain biologically relevant information relating to the body tissues, adhesives, and shell of the organisms, an in situ sample environment was developed to allow direct microprobe investigation of hydrated specimens without pretreatment of the samples. In 8-day-old juvenile barnacles (Balanus improvisus), the junctions between the six plates forming the shell wall showed elevated concentrations of calcium, potassium, bromine, strontium, and manganese. Confocal measurements allowed elemental characterization of the adhesive interface of recently attached cyprids (Balanus amphitrite), and substantiated the accumulation of bromine both at the point of initial attachment as well as within the cyprid carapace. In situ measurements of the cyprid cement established the presence of bromine, chlorine, iodine, sulfur, copper, iron, zinc, selenium, and nickel for both species. The previously unrecognized presence of bromine, iron, and selenium in the cyprid permanent adhesive will hopefully inspire further biochemical investigations of the function of these substances. PMID:26715248

  14. Acute effects of taurine on sarcoplasmic reticulum Ca2+ accumulation and contractility in human type I and type II skeletal muscle fibers.

    Science.gov (United States)

    Dutka, T L; Lamboley, C R; Murphy, R M; Lamb, G D

    2014-10-01

    Taurine occurs in high concentrations in muscle and is implicated in numerous physiological processes, yet its effects on many aspects of contractility remain unclear. Using mechanically skinned segments of human vastus lateralis muscle fibers, we characterized the effects of taurine on sarcoplasmic reticulum (SR) Ca2+ accumulation and contractile apparatus properties in type I and type II fibers. Prolonged myoplasmic exposure (>10 min) to taurine substantially increased the rate of accumulation of Ca2+ by the SR in both fiber types, with no change in the maximum amount accumulated; no such effect was found with carnosine. SR Ca2+ accumulation was similar with 10 or 20 mM taurine, but was significantly slower at 5 mM taurine. Cytoplasmic taurine (20 mM) had no detectable effects on the responsiveness of the Ca2+ release channels in either fiber type. Taurine caused a small increase in Ca2+ sensitivity of the contractile apparatus in type I fibers, but type II fibers were unaffected; maximum Ca(2+)-activated force was unchanged in both cases. The effects of taurine on SR Ca2+ accumulation (1) only became apparent after prolonged cytoplasmic exposure, and (2) persisted for some minutes after complete removal of taurine from the cytoplasm, consistent with the hypothesis that the effects were due to an action of taurine from inside the SR. In summary, taurine potentiates the rate of SR Ca2+ uptake in both type I and type II human fibers, possibly via an action from within the SR lumen, with the degree of potentiation being significantly reduced at low physiological taurine levels. PMID:25123198

  15. Migrations of California gray whales tracked by oxygen-18 variations in their epizoic barnacles

    International Nuclear Information System (INIS)

    Barnacles attached to the California gray whale have oxygen isotope compositions that serve as a record of changing ocean temperatures as the whale migrates between arctic and subtropical waters. The isotopic values for the barnacles can be used to track whale migrations and to reconstruct the recent movements of beached whales. The method may be useful for tracing the movements of other animals, living or fossil, and for reconstructing the voyages of ancient ships

  16. Analysis on muscle fiber development and muscle quality in pure lines of quality broilers%不同品系优质鸡肌纤维生长规律及其与肉品质的关系

    Institute of Scientific and Technical Information of China (English)

    黎寿丰; 赵振华; 黄华云; 李春苗; 薛龙岗

    2013-01-01

    以3个日龄的5个品系F、D、Y、S、B优质肉鸡为试验对象,采用组织化学切片染色技术进行组织学观察,探讨优质鸡肌纤维的发育规律及其对肉品质的影响.结果表明,随着日龄的增加鸡肌纤维的发育呈明显变化.70-90日龄的肌纤维面积的生长强度小于90-120日龄,而肌纤维密度70-90日龄的生长强度大于90-120日龄.同一生长阶段不同品系间肌纤维的生长强度也明显不同,生长较快的D系肌纤维生长强度最大.相关分析表明,肌纤维面积与肌纤维密度呈极显著负相关(P<0.01),与硫胺素含量呈显著正相关(P<0.05),与嫩度、肉色、肌内脂肪含量、肌苷酸含量呈正相关,但相关性不显著(P>0.05).可见,肌纤维的生长发育对肌肉的干物质、肌内脂肪等肉质性状及硫胺素、肌苷酸等风味物质的产生有利.%5 quality broiler lines at three growth stages were selected for study. Histochemical staining technique was used to explore the effect of muscle fiber development and muscle quality in quality broiler. The results indicated that muscle fibers of chicken appeared a significant development with days increasing, and which showed a lower growth intensity at the age of 70 - 90 days than those at the age of 90 - 120 days in the fiber areas. Just right opposite compare with the fiber areas, at the age of 70 - 90 days growed higher than those at the age of 90 - 120 days in the fiber density. The muscle fiber of different lines had different growth intensity at the same period, line D grew much faster than others. Correlation analysis showed that the fiber areas had a significant negative correlation with fiber density (P 0.05 ) . The growth and development of muscle fiber may have positive effects on muscle quality traits, such as dry matter, intramuscular fat, and thiamine, ion-sine monophosphate of flavor compounds.

  17. Contribution of stretch to the change of activation properties of muscle fibers in the diaphragm at the transition from fetal to neonatal life.

    Directory of Open Access Journals (Sweden)

    David J Cannata

    2011-12-01

    Full Text Available The transition from fetal to postnatal life involves clearance of liquid from the lung and airways, and rapid formation of a functional residual capacity. Despite the importance of the diaphragm in this process, the impact on the mechanical and functional activity changes of its muscle fibers is not known. This study determined the contractile characteristics of individual ‘skinned’ diaphragm fibers from 70 days gestation to adulthood in sheep, and determined the impact of the transition from the in utero fetal status to (a, spontaneous air breathing; or (b mechanical ventilation - on passive tension and calcium- and strontium-activated properties of single fibers isolated from the diaphragm. Based on differential sensitivity to the divalent ions calcium (Ca2+ and strontium (Sr2+, all fibers in the fetal diaphragm were classified as ‘fast’, whereas fibers from the adult diaphragm exhibited a ‘hybrid’ phenotype wherein both ‘fast’ and ‘slow’ characteristics were present within each single fiber. Transition to the hybrid phenotype occurred at birth, was evident after 40 mins of spontaneous breathing, and could be induced by mechanical stretch of diaphragm fibers from near term foetuses (~147 days gestation. Applied stretch of fibers, achieved either by physical stretch of isolated fibres or mechanical ventilation of the fetus, significantly increased sensitivity to Ca2+ and Sr2+, maximum force generating capacity, and decreased passive tension in near-term and preterm fetuses. However, only fibers from near-term fetuses displayed a complete transition to a ‘hybrid’ activation profile., These findings suggest that activation properties of the diaphragm are changed by transition from a liquid to air-filled lung at birth, and that stretch induces physical changes of proteins determining the activation and elastic properties of the diaphragm. These changes may allow the diaphragm to meet the increased mechanical demands of

  18. Increased algal fouling on mussels with barnacle epibionts: a fouling cascade

    Science.gov (United States)

    Gutiérrez, Jorge L.; Palomo, M. Gabriela

    2016-06-01

    If the external surfaces of epibionts are more suitable to other fouling species than those of their basibionts, a 'fouling cascade' might occur where epibionts facilitate secondary colonization by other epibionts. Here we evaluate whether the presence of epibiotic barnalces (Balanus glandula) influences the probability of mussel (Brachidontes rodriguezii) fouling by ephemeral red algae (Porphyra sp.) in a Southwestern Atlantic rocky shore. Mussels with barnacle epibionts showed a higher prevalence of Porphyra sp. fouling (32-40% depending on sampling date) than mussels without them (3-7%). Two lines of evidence indicate that barnacles facilitate Porphyra sp. fouling. First, most Porphyra sp. thalli in mussels with barnacle epibionts were attached to barnacle shells (75-92% of cases). Secondly, Porphyra sp. associated with mussels with barnacle epibionts in a proportion that significantly exceeded that expected under random co-occurrence. These results suggest the occurrence of a fouling cascade where barnacle epibiosis on mussels facilitates subsequent algal fouling. Recognizing the occurrence of such fouling cascades is important because they might explain the non-random aggregation of multiple epibiotic species onto a proportionally few individuals of the host species.

  19. Larval vision contributes to gregarious settlement in barnacles: adult red fluorescence as a possible visual signal

    KAUST Repository

    Matsumura, K.

    2014-02-26

    Gregarious settlement, an essential behavior for many barnacle species that can only reproduce by mating with a nearby barnacle, has long been thought to rely on larval ability to recognize chemical signals from conspecifics during settlement. However, the cyprid, the settlement stage larva in barnacles, has one pair of compound eyes that appear only at the late nauplius VI and cyprid stages, but the function(s) of these eyes remains unknown. Here we show that cyprids of the intertidal barnacle Balanus (=Amphibalanus) amphitrite can locate adult barnacles even in the absence of chemical cues, and prefer to settle around them probably via larval sense of vision. We also show that the cyprids can discriminate color and preferred to settle on red surfaces. Moreover, we found that shells of adult B. amphitrite emit red auto-fluorescence and the adult extracts with the fluorescence as a visual signal attracted cyprid larvae to settle around it. We propose that the perception of specific visual signals can be involved in behavior of zooplankton including marine invertebrate larvae, and that barnacle auto-fluorescence may be a specific signal involved in gregarious larval settlement.

  20. Effect of dietary zinc and ractopamine hydrochloride on pork chop muscle fiber type distribution, tenderness, and color characteristics.

    Science.gov (United States)

    Paulk, C B; Tokach, M D; Nelssen, J L; Burnett, D D; Vaughn, M A; Phelps, K J; Dritz, S S; Derouchey, J M; Goodband, R D; Woodworth, J C; Houser, T A; Haydon, K D; Gonzalez, J M

    2014-05-01

    A total of 320 finishing pigs (PIC 327 × 1050; initially 98 kg) were used to determine the effects of adding Zn to diets containing ractopamine HCl (RAC) on muscle fiber type distribution, fresh chop color, and cooked meat characteristics. Dietary treatments were fed for approximately 35 d and consisted of a corn-soybean meal-based negative control (CON), a positive control diet with 10 mg/kg of RAC (RAC+), and the RAC+ diet plus 75, 150, or 225 mg/kg added Zn from either ZnO or Availa-Zn. Loins randomly selected from each treatment (n = 20) were evaluated using contrasts: CON vs. RAC+, interaction of Zn level × source, Zn level linear and quadratic polynomials, and Zn source. There were no Zn source effects or Zn source × level interactions throughout the study (P > 0.10). Pigs fed RAC+ had increased (P 0.07). In conclusion, RAC+ diets produced chops that were lighter and less red but maintained a greater percentage of surface oxymyoglobin throughout a 5-d simulated retail display. Ractopamine reduced MRA at the end of the display period, but supplementing Zn to RAC diets restored MRA to near CON treatment levels at the end of the display period. PMID:24671591

  1. Worldwide genetic differentiation in the common fouling barnacle, Amphibalanus amphitrite

    KAUST Repository

    Chen, Hsi-Nien

    2014-10-21

    © 2014, © 2014 Taylor & Francis. Amphibalanus amphitrite is a common fouling barnacle distributed globally in tropical and subtropical waters. In the present study, the genetic (mitochondrial cytochrome oxidase subunit I) and morphological differentiation in A. amphitrite from 25 localities around the world were investigated. The results revealed three clades within A. amphitrite with a genetic divergence of ~ 4% among clades, whereas there were no diagnostic morphological differences among clades. Clade 1 is widely distributed in both temperate and tropical waters, whereas Clade 3 is currently restricted to the tropical region. The deep divergence among clades suggests historical isolation within A. amphitrite; thus, the present geographical overlaps are possibly a result of the combined effects of rising sea level and human-mediated dispersals. This study highlights the genetic differentiation that exists in a common, widely distributed fouling organism with great dispersal potential; future antifouling research should take into account the choice of lineages.

  2. GLUT4 is reduced in slow muscle fibers of type 2 diabetic patients: is insulin resistance in type 2 diabetes a slow, type 1 fiber disease?

    DEFF Research Database (Denmark)

    Gaster, M; Staehr, P; Beck-Nielsen, H;

    2001-01-01

    morphometry, GLUT4 density was found to be significantly higher in slow compared with fast fibers in biopsy specimens from lean and obese subjects. In contrast, in type 2 diabetic subjects, GLUT4 density was significantly lower in slow compared with fast fibers. GLUT4 density in slow fibers from diabetic...

  3. Fiber

    Science.gov (United States)

    ... a fiber-rich sandwich with whole-grain bread, peanut butter, and bananas. Use whole-grain spaghetti and other ... cookies and muffins. Top whole-wheat crackers with peanut butter or low-fat cheese. Go easy on the ...

  4. Downhill Running Excessive Training Inhibits Hypertrophy in Mice Skeletal Muscles with Different Fiber Type Composition.

    Science.gov (United States)

    da Rocha, Alisson L; Pereira, Bruno C; Pauli, José R; de Souza, Claudio T; Teixeira, Giovana R; Lira, Fábio S; Cintra, Dennys E; Ropelle, Eduardo R; Júnior, Carlos R B; da Silva, Adelino S R

    2016-05-01

    The aim of this study was to verify the effects of running overtraining protocols performed in downhill, uphill, and without inclination on the proteins related to hypertrophy signaling pathway in extensor digitorum longus (EDL) and soleus of C57BL/6 mice. We also performed histological and stereological analyses. Rodents were divided into control (CT; sedentary mice), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up), and overtrained by running without inclination (OTR). The incremental load, exhaustive, and grip force tests were used as performance evaluation parameters. 36 h after the grip force test, EDL and soleus were removed and immediately used for immunoblotting analysis or stored at -80°C for histological and stereological analyses. For EDL, OTR/down decreased the protein kinase B (Akt) and tuberous sclerosis protein 2 (TSC2) phosphorylation (p), and increased myostatin, receptor-activated Smads (pSMAD2-3), and insulin receptor substrate-1 (pIRS-1; Ser307/636). OTR/down also presented low and high relative proportions of cytoplasm and connective tissue, respectively. OTR/up increased the mammalian target of rapamycin (pmTOR), 70-kDa ribosomal protein S6 kinase 1 (pS6K1) and pSMAD2-3, and decreased pTSC2. OTR decreased pTSC2 and increased pIRS-1 (Ser636). For soleus, OTR/down increased S6 ribosomal protein (pS6RP) and pSMAD2-3, and decreased pIRS-1 (Ser639). OTR/up decreased pS6K1, pS6RP and pIRS-1 (Ser639), and increased pTSC2 (Ser939), and pSMAD2-3. OTR increased pS6RP, 4E-binding protein-1 (p4E-BP1), pTSC2 (Ser939), and pSMAD2-3, and decreased pIRS-1 (Ser639). In summary, OTR/down inhibited the skeletal muscle hypertrophy with concomitant signs of atrophy in EDL. The effects of OTR/up and OTR depended on the analyzed skeletal muscle type. J. Cell. Physiol. 231: 1045-1056, 2016. © 2015 Wiley Periodicals, Inc. PMID:26381504

  5. Antifouling Activity of Synthetic Alkylpyridinium Polymers Using the Barnacle Model

    Directory of Open Access Journals (Sweden)

    Veronica Piazza

    2014-04-01

    Full Text Available Polymeric alkylpyridinium salts (poly-APS isolated from the Mediterranean marine sponge, Haliclona (Rhizoniera sarai, effectively inhibit barnacle larva settlement and natural marine biofilm formation through a non-toxic and reversible mechanism. Potential use of poly-APS-like compounds as antifouling agents led to the chemical synthesis of monomeric and oligomeric 3-alkylpyridinium analogues. However, these are less efficient in settlement assays and have greater toxicity than the natural polymers. Recently, a new chemical synthesis method enabled the production of poly-APS analogues with antibacterial, antifungal and anti-acetylcholinesterase activities. The present study examines the antifouling properties and toxicity of six of these synthetic poly-APS using the barnacle (Amphibalanus amphitrite as a model (cyprids and II stage nauplii larvae in settlement, acute and sub-acute toxicity assays. Two compounds, APS8 and APS12-3, show antifouling effects very similar to natural poly-APS, with an anti-settlement effective concentration that inhibits 50% of the cyprid population settlement (EC50 after 24 h of 0.32 mg/L and 0.89 mg/L, respectively. The toxicity of APS8 is negligible, while APS12-3 is three-fold more toxic (24-h LC50: nauplii, 11.60 mg/L; cyprids, 61.13 mg/L than natural poly-APS. This toxicity of APS12-3 towards nauplii is, however, 60-fold and 1200-fold lower than that of the common co-biocides, Zn- and Cu-pyrithione, respectively. Additionally, exposure to APS12-3 for 24 and 48 h inhibits the naupliar swimming ability with respective IC50 of 4.83 and 1.86 mg/L.

  6. Lack of on-going adaptations in the soleus muscle activity during walking in patients affected by large-fiber neuropathy

    DEFF Research Database (Denmark)

    Nazarena, Mazzaro; Grey, Michael James; Sinkjær, Thomas;

    2005-01-01

    The aim of this study was to investigate the contribution of feedback from large-diameter sensory fibers to the adaptation of soleus muscle activity after small ankle trajectory modifications during human walking. Small-amplitude and slow-velocity ankle dorsiflexion enhancements and reductions were...... applied during the stance phase of the gait cycle to mimic the normal variability of the ankle trajectory during walking. Patients with demyelination of large sensory fibers (Charcot-Marie-Tooth type 1A and antibodies to myelin-associated glycoprotein neuropathy) and age-matched controls participated in...... this study. The patients had absent light-touch sense in the toes and feet and absent quadriceps and Achilles tendon reflexes, indicating functional loss of large sensory fibers. Moreover, their soleus stretch reflex response consisted of a single electromyographic (EMG) burst with delayed onset and...

  7. Effects of acute exposure of heavy ion to spinal cord on the properties of motoneurons and muscle fibers in rats (the 3rd report)

    International Nuclear Information System (INIS)

    The effects of acute exposure of heavy ion on the properties of spinal motoneurons and their innervating muscle fibers were investigated. A 15, 20, 40, 50, or 70 Gy dose of heavy ion was applied to the lumbar 4th to 6th segments of the spinal cord in 8-week-old male rats. Both the control and heavy-ion-exposed rats were sacrificed one month after exposure to heavy ion. The number, cell body size, and oxidative enzyme activity of spinal motoneurons innervating the soleus and plantaris muscles were analyzed by a computer-assisted image processing system. In addition, cell size, oxidative enzyme activity, and expression of myosin heavy chain isoforms in the soleus and plantaris muscles were analyzed. There were no differences in the number of spinal motoneurons innervating the soleus and plantaris muscles between the control and heavy-ion-exposed rats, irrespective of the dose level. On the other hand, cell body sizes were decreased and oxidative enzyme activities were disappeared in spinal motoneurons of the heavy-ion-exposed rats at the dose levels of 40, 50, and 70 Gy. There were no differences in the cell size, oxidative enzyme activity, or expression of myosin heavy chain isoforms of the soleus and plantaris muscles between the control and heavy-ion-exposed rats, irrespective of the dose level. It is concluded that more than 40 Gy dose of heavy ion affects the properties of spinal motoneurons, although there are no influences on the properties of muscle fibers which they innervate. (author)

  8. Genetics Home Reference: rippling muscle disease

    Science.gov (United States)

    ... sudden impact on the muscle causes it to bunch up (percussion-induced muscle mounding) or exhibit repetitive ... potentials in the tubular system of skeletal muscle fibers. Muscle Nerve. 2005 May;31(5):652-8. ...

  9. Skeletal muscle eEF2 and 4EBP1 phosphorylation during endurance exercise is dependent on intensity and muscle fiber type

    DEFF Research Database (Denmark)

    Rose, Adam John; Bisiani, Bruno; Vistisen, Bodil; Kiens, Bente; Richter, Erik

    2009-01-01

    ) increased during exercise but was not influenced by exercise intensity, and was lower than rest 30min after exercise. On the other hand, 4EBP1 phosphorylation at Thr(37/46) decreased during exercise and this decrease was greater at higher exercise intensities, and was similar to rest 30min after exercise......Protein synthesis in skeletal muscle is known to decrease during exercise and it has been suggested that this may depend on the magnitude of the relative metabolic stress within the contracting muscle. To examine the mechanisms behind this, the effect of exercise intensity on skeletal muscle...... that the increase in skeletal muscle eEF2 Thr(56) phosphorylation was restricted to type I myofibers. Taken together, these data suggest that the depression of skeletal muscle protein synthesis with endurance-type exercise may be regulated at both initiation (i.e. 4EBP1) and elongation (i.e. eEF2...

  10. Changes in ACTN3 gene expression and fiber type composition in flexor hallucis longus muscle after eight weeks progressive resistance training in Sprague-Dawley rats

    Directory of Open Access Journals (Sweden)

    Ali Gaeini A

    2013-04-01

    Full Text Available Background: Alpha-actinins are located in the skeletal muscle Z-line and form actin–actin cross-links. It belongs to a highly conserved family of actin-binding proteins- the spectrin superfamily, which also contains the spectrins and dystrophin. Mammalian skeletal muscle has two isoforms: alpha-actinins-2 and alpha-actinins-3. However, the response of alpha-actinins to exercise training is little understood. This study examined the effects of 8 weeks of resistance training on muscle mass, ACTN3 (alpha-actinins-3 gene expression levels and fiber type composition in the flexor hallucis longus (FHL muscle.Methods: Forty five female Sprague-Dawley rats (Initial body mass: 169.25±9gr age: 3 month were obtained and assigned to a control (C; n=18 or exercise training (T; n=22 and pilot (P; n=5 groups. The resistance training consisted of climbing a ladder carry-ing a load suspended from the tail and the weight increased progressively. Real-time PCR and Immunohistochemistry techniques were used to measure gene expression leve-ls and myosin heavy chain (MyHC composition, respectively.Results: Following 8 weeks of training, we observed significant increase in absolute muscle mass in FHL (P=0.01. Results showed that no significant difference was found in ACTN3 gene expression levels between training and control groups (P=0.852 respecti-vely. Also, Pearson coefficient didn't indicated any significant relationships in gene expression and Fiber type IIX in response to resistance training in FHL (r=0.12.Conclusion: However, resistance training effects on sarcomeric proteins development, these results showed no effect of resistance training on alpha-actinins-3 levels. Althou-gh alpha-actinins-3 has an important function to produce and progress of force in sarco-mere, but didn't changed significantly in response to resistance training.

  11. Muscle power failure in mobility-limited older adults: preserved single fiber function despite lower whole muscle size, quality and rate of neuromuscular activation

    OpenAIRE

    Reid, Kieran F.; Doros, Gheorghe; Clark, David J.; Patten, Carolynn; Carabello, Robert J.; Cloutier, Gregory J.; Phillips, Edward M.; Krivickas, Lisa S.; Frontera, Walter R.; FIELDING, ROGER A.

    2011-01-01

    This study investigated the physiological and gender determinants of the age-related loss of muscle power in 31 healthy middle-aged adults (aged 40–55 years), 28 healthy older adults (70–85 years) and 34 mobility-limited older adults (70–85 years). We hypothesized that leg extensor muscle power would be significantly lower in mobility-limited elders relative to both healthy groups and sought to characterize the physiological mechanisms associated with the reduction of muscle power with aging....

  12. Selective expression of the type 3 isoform of ryanodine receptor Ca2+ release channel (RyR3) in a subset of slow fibers in diaphragm and cephalic muscles of adult rabbits

    International Nuclear Information System (INIS)

    The expression pattern of the RyR3 isoform of Ca2+ release channels was analysed by Western blot in neonatal and adult rabbit skeletal muscles. The results obtained show that the expression of the RyR3 isoform is developmentally regulated. In fact, RyR3 expression was detected in all muscles analysed at 2 and 15 days after birth while, in adult animals, it was restricted to a subset of muscles that includes diaphragm, masseter, pterygoideus, digastricus, and tongue. Interestingly, all of these muscles share a common embryonic origin being derived from the somitomeres or from the cephalic region of the embryo. Immunofluorescence analysis of rabbit skeletal muscle cross-sections showed that RyR3 staining was detected in all fibers of neonatal muscles. In contrast, in those adult muscles expressing RyR3 only a fraction of fibers was labelled. Staining of these muscles with antibodies against fast and slow myosins revealed a close correlation between expression of RyR3 and fibers expressing slow myosin isoform

  13. The unexpected mating system of the androdioecious barnacle Chelonibia testudinaria (Linnaeus 1758).

    Science.gov (United States)

    Ewers-Saucedo, Christine; Hope, Neva B; Wares, John P

    2016-05-01

    Androdioecy was first described by Darwin in his seminal work on barnacle diversity; he identified males and hermaphrodites in the same reproductive population. Today, we realize that many androdioecious plants and animals share astonishing similarities, particularly with regard to their evolutionary history and mating system. Notably, these species were ancestrally dioecious, and their mating system has the following characteristics: hermaphrodites self-fertilize frequently, males are more successful in large mating groups, and males have a mating advantage. A male mating advantage makes androdioecy more likely to persist over evolutionary times. Androdioecious barnacles, however, appear to persist as an outlier with a different evolutionary trajectory: they originate from hermaphroditic species. Although sexual systems of androdioecious barnacles are known, no information on the mating system of androdioecious barnacles is available. This study assessed the mating system of the androdioecious barnacle Chelonibia testudinaria. In contrast to other androdioecious species, C. testudinaria does not self-fertilize, males do not have a mating advantage over hermaphrodites, and the average mating group is quite small, averaging only three individuals. Mating success is increased by proximity to the mate and penis length. Taken together, the mating system of C. testudinaria is unusual in comparison with other androdioecious plants and animals, and the lack of a male mating advantage suggests that the mating system alone does not provide an explanation for the maintenance of androdioecy in this species. Instead, we propose that sex-specific life history equalizes male and hermaphroditic overall fitness. PMID:26923636

  14. Unchanged content of oxidative enzymes in fast-twitch muscle fibers and V˙O2 kinetics after intensified training in trained cyclists

    DEFF Research Database (Denmark)

    Christensen, Peter Møller; Gunnarsson, Thomas Gunnar Petursson; Thomassen, Martin;

    2015-01-01

    perturbation during INT. Pulmonary V˙O2 kinetics was determined in eight trained male cyclists (V˙O2-max: 59 ± 4 (means ± SD) mL min(-1) kg(-1)) during MOD (205 ± 12 W ~65% V˙O2-max) and INT (286 ± 17 W ~85% V˙O2-max) exercise before and after a 7-week HIT period (30-sec sprints and 4-min intervals) with a 50......The present study examined if high intensity training (HIT) could increase the expression of oxidative enzymes in fast-twitch muscle fibers causing a faster oxygen uptake (V˙O2) response during intense (INT), but not moderate (MOD), exercise and reduce the V˙O2 slow component and muscle metabolic...... between MOD and INT. Muscle creatine phosphate was lower (42 ± 15 vs. 66 ± 17 mmol kg DW(-1)) and muscle lactate was higher (40 ± 18 vs. 14 ± 5 mmol kg DW(-1)) at 6 min of INT (P < 0.05) after compared to before HIT. A period of intensified training with a volume reduction did not increase the content of...

  15. An intronic enhancer containing an N-box motif is required for synapse- and tissue-specific expression of the acetylcholinesterase gene in skeletal muscle fibers

    OpenAIRE

    Chan, Roxanne Y. Y.; Boudreau-Larivière, Céline; Angus, Lindsay M.; Mankal, Fawzi A.; Jasmin, Bernard J.

    1999-01-01

    mRNAs encoding acetylcholinesterase (AChE; EC 3.1.1.7) are highly concentrated within the postsynaptic sarcoplasm of adult skeletal muscle fibers, where their expression is markedly influenced by nerve-evoked electrical activity and trophic factors. To determine whether transcriptional regulatory mechanisms account for the synaptic accumulation of AChE transcripts at the mammalian neuromuscular synapse, we cloned a 5.3-kb DNA fragment that contained the 5′ regulatory region of the rat AChE ge...

  16. Expression of a Dominant Negative CELF Protein In Vivo Leads to Altered Muscle Organization, Fiber Size, and Subtype

    OpenAIRE

    Berger, Dara S.; Moyer, Michelle; Kliment, Gregory M.; van Lunteren, Erik; Ladd, Andrea N

    2011-01-01

    Background CUG-BP and ETR-3-like factor (CELF) proteins regulate tissue- and developmental stage-specific alternative splicing in striated muscle. We previously demonstrated that heart muscle-specific expression of a nuclear dominant negative CELF protein in transgenic mice (MHC-CELFΔ) effectively disrupts endogenous CELF activity in the heart in vivo, resulting in impaired cardiac function. In this study, transgenic mice that express the dominant negative protein under a skeletal muscle-spec...

  17. Detection of deleted mitochondrial genomes in cytochrome-c oxidase-deficient muscle fibers of a patient with Kearns-Sayre syndrome

    International Nuclear Information System (INIS)

    Using in situ hybridization and immunocytochemistry, the authors studied a muscle biopsy sample from a patient with Kearns-Sayre syndrome (KSS) who had a deletion of mitochondrial DNA (mtDNA) and partial deficiency of cytochrome-c oxidase. They sought a relationship between COX deficiency and abnormalities of mtDNA at the single-fiber level. COX deficiency clearly correlated with a decrease of normal mtDNA and, conversely, deleted mtDNA was more abundant in COX-deficient fibers, especially ragged-red fibers. The distribution of mtRNA has a similar pattern, suggesting that deleted mtDNA is transcribed. Immunocytochemistry showed that the nuclear DNA-encoded subunit IV of COX was present but that the mtDNA-encoded subunit II was markedly diminished in COX-deficient ragged-red fibers. Because the mtDNA deletion in this patient did not comprise the gene encoding COX subunit II, COX deficiency may have resulted from lack of translation of mtRNA encoding all three mtDNA-encoded subunits of COX

  18. Effect of ADP on the orientation of spin-labeled myosin heads in muscle fibers: A high-resolution study with deuterated spin labels

    International Nuclear Information System (INIS)

    We have used electron paramagnetic resonance (EPR) to determine the effects of ADP on the orientational distribution of nitroxide spin labels attached to myosin heads in skinned rabbit psoas muscle fibers. To maximize the specificity of labeling, we spin-labeled isolated myosin heads (subfragment 1) on a single reactive thiol (SH1) and diffused them into unlabeled muscle fibers. To maximize spectral and orientational resolution, we used perdeuterated spin labels, 2H-MSL and 2H-IASL, eliminating superhyperfine broadening and thus narrowing the line widths. Two different spin labels were used, with different orientation relative to the myosin head, to ensure that the results are not affected by unfavorable probe orientation. In rigor, a very narrow three-line spectrum was observed for both spin labels, indicating a narrow orientational distribution, as reported previously. ADP induced very slight changes in the spectrum, corresponding to very slight (but significant) changes in the orientational distribution. These changes were quantified by a digital analysis of the spectra, using a two-step simplex fitting procedure. First, the magnetic tensor values and line widths were determined by fitting the spectrum of a randomly oriented sample. Then the spectrum of oriented fibers was fit to a model by assuming a Gaussian distribution of the tilt angle (theta) and twist angle (phi) of the nitroxide principal axes relative to the fiber axis. A single-Gaussian distribution resulted in inadequate fits, but a two-component model gave excellent results. ADP induces a small (less than 5 degrees) rotation of the major components for both spin labels, along with a similarly small increase of disorder about the average positions

  19. Mg/Ca and isotopic high resolution record of deep-sea hydrothermal barnacles

    Science.gov (United States)

    Bojar, A.-V.; Bojar, H.-P.; Tufar, W.

    2012-04-01

    Barnacles are crustaceans adapted to a sessile existence and cemented to a substrate by a protein complex. Most of the known species inhabit shallow marine environment, less than 2% of the species are found at depths between 100 and 2500 m. The shell of barnacles has a great adaptive significance, the shell of some barnacle species have been already investigated for microstructure. In this study we investigated the shell microstructure as well as the Mg/Ca and stable isotope distribution of barnacles found at a depth of around 2500m at a black smoker from the Manus Spreading centre, north-east of Papua New Guinea. The shell consists of three substructures: an outer layer with pores and aragonite crystals, a massive interior mass and an inner layer with pores. The shell shows grown lines and the outer layer exhibits longitudinal striation from base to apex. The pores have a medium size of 0.8 microns. The size of the calcitic microcrystals are in the range of 0.2 to 0.5 microns, beside, larger aragonite crystals, with size of c. 10 microns are present. The massive interior mass has a compact structure, no pores or channels could be observed. Oxygen stable isotope data of barnacle shell were performed from the centre to the border of the calcitic shells, along profiles. Within one shell, the isotope values show variations of max. 0.6 ‰. The calculated temperatures from the stable isotope data consistently indicate that the barnacles populate sites with low temperature values, up to a few °C. The calculated temperatures from the isotope data are also in agreement with the reported habitat from the North Fiji and Lau Basins, where temperatures of max. 6°C were measured at sites populated by barnacles. Both calculated and measured temperatures of a few degrees indicate that at the sites where barnacles live, hydrothermal fluid input is present, as ambient temperature is around 1.5°C. Electron-microbeam analyses were done along the interior layer of the shell. The

  20. Distribution and threshold expression of the tRNA[sup Lys] mutation in skeletal muscle of patients with myoclonic epilepsy and ragged-red fibers (MERRF)

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, L.; Karpati, G. (Montreal Neurological Inst., Quebec (Canada)); Shoubridge, E.A. (Montreal Neurological Inst., Quebec (Canada) McGill Univ., Montreal, Quebec (Canada))

    1992-12-01

    The authors investigated the distribution and expression of mutant mtDNAs carrying the A-to-G mutation at position 8344 in the tRNA[sup Lys] gene in the skeletal muscle of four patients with myoclonus epilepsy and ragged-red fibers (MERRF). The proportion of mutant genomes was greater than 80% of total mtDNAs in muscle samples of all patients and was associated with a decrease in the activity of cytochrome c oxidase (COX). The vast majority of myoblasts, cloned from the satellite-cell population in the same muscles, were homoplasmic for the mutation. The overall proportion of mutant mtDNAs in this population was similar to that in differentiated muscle, suggesting that the ratio of mutant to wild-type mtDNAs in skeletal muscle is determined either in the ovum or during early development and changes little with age. Translation of all mtDNA-encoded genes was severely depressed in homoplasmic mutant myoblast clones but not in heteroplasmic or wild-type clones. The threshold for biochemical expression of the mutation was determined in heteroplasmic myotubes formed by fusion of different proportions of mutant and wild-type myoblasts. The magnitude of the decrease in translation in myotubes containing mutant mtDNAs was protein specific. Complex I and IV subunits were more affected than complex V subunits, and there was a rough correlation with both protein size and number of lysine residues. Approximately 15% wild-type mtDNAs restored translation and COX activity to near normal levels. These results show that the A-to-G substitution in tRNA[sup Lys] is a functionally recessive mutation that can be rescued by intraorganellar complementation with a small proportion of wild-type mtDNAs and explain the steep threshold for expression of the MERRF clinical phenotype. 40 refs., 7 figs., 2 tabs.

  1. Analysis of the behaviours mediating barnacle cyprid reversible adhesion.

    Directory of Open Access Journals (Sweden)

    Nick Aldred

    Full Text Available When exploring immersed surfaces the cypris larvae of barnacles employ a tenacious and rapidly reversible adhesion mechanism to facilitate their characteristic 'walking' behaviour. Although of direct relevance to the fields of marine biofouling and bio-inspired adhesive development, the mechanism of temporary adhesion in cyprids remains poorly understood. Cyprids secrete deposits of a proteinaceous substance during surface attachment and these are often visible as 'footprints' on previously explored surfaces. The attachment structures, the antennular discs, of cyprids also present a complex morphology reminiscent of both the hairy appendages used by some terrestrial invertebrates for temporary adhesion and a classic 'suction cup'. Despite the numerous analytical approaches so-far employed, it has not been possible to resolve conclusively the respective contributions of viscoelastic adhesion via the proteinaceous 'temporary adhesive', 'dry' adhesion via the cuticular villi present on the disc and the behavioural contribution by the organism. In this study, high-speed photography was used for the first time to capture the behaviour of cyprids at the instant of temporary attachment and detachment. Attachment is facilitated by a constantly sticky disc surface - presumably due to the presence of the proteinaceous temporary adhesive. The tenacity of the resulting bond, however, is mediated behaviourally. For weak attachment the disc is constantly moved on the surface, whereas for a strong attachment the disc is spread out on the surface. Voluntary detachment is by force, requiring twisting or peeling of the bond - seemingly without any more subtle detachment behaviours. Micro-bubbles were observed at the adhesive interface as the cyprid detached, possibly an adaptation for energy dissipation. These observations will allow future work to focus more specifically on the cyprid temporary adhesive proteins, which appear to be fundamental to adhesion

  2. Analysis of the behaviours mediating barnacle cyprid reversible adhesion.

    Science.gov (United States)

    Aldred, Nick; Høeg, Jens T; Maruzzo, Diego; Clare, Anthony S

    2013-01-01

    When exploring immersed surfaces the cypris larvae of barnacles employ a tenacious and rapidly reversible adhesion mechanism to facilitate their characteristic 'walking' behaviour. Although of direct relevance to the fields of marine biofouling and bio-inspired adhesive development, the mechanism of temporary adhesion in cyprids remains poorly understood. Cyprids secrete deposits of a proteinaceous substance during surface attachment and these are often visible as 'footprints' on previously explored surfaces. The attachment structures, the antennular discs, of cyprids also present a complex morphology reminiscent of both the hairy appendages used by some terrestrial invertebrates for temporary adhesion and a classic 'suction cup'. Despite the numerous analytical approaches so-far employed, it has not been possible to resolve conclusively the respective contributions of viscoelastic adhesion via the proteinaceous 'temporary adhesive', 'dry' adhesion via the cuticular villi present on the disc and the behavioural contribution by the organism. In this study, high-speed photography was used for the first time to capture the behaviour of cyprids at the instant of temporary attachment and detachment. Attachment is facilitated by a constantly sticky disc surface - presumably due to the presence of the proteinaceous temporary adhesive. The tenacity of the resulting bond, however, is mediated behaviourally. For weak attachment the disc is constantly moved on the surface, whereas for a strong attachment the disc is spread out on the surface. Voluntary detachment is by force, requiring twisting or peeling of the bond - seemingly without any more subtle detachment behaviours. Micro-bubbles were observed at the adhesive interface as the cyprid detached, possibly an adaptation for energy dissipation. These observations will allow future work to focus more specifically on the cyprid temporary adhesive proteins, which appear to be fundamental to adhesion, inherently sticky and

  3. Inhibition of myosatellite cell proliferation by gamma irradiation does not prevent the age-related increase of the number of dystrophin-positive fibers in soleus muscles of mdx female heterozygote mice

    International Nuclear Information System (INIS)

    In skeletal muscles of young mdx female heterozygote mice, there is a mosaic of dystrophin-positive and dystrophin-negative fiber segments. In older animals, there is a marked decline in the number of dystrophin-negative fiber segments. This phenomenon might be due to a fusion of dystrophin-competent satellite cells into the originally dystrophin-negative fiber segments during growth. To study this possibility, soleus muscles of 10-day-old mdx female heterozygotes were gamma irradiated (2000 rads) to inhibit subsequent myosatellite cell proliferation and fusion. In the irradiated soleus muscles of animals at 60 days, the relative amount of dystrophin measured by quantitative immunoblots was not significantly different from that of the contralateral nonirradiated muscles. The prevalence of dystrophin-negative fibers in the 60-day-old irradiated solei was not higher than in the nonirradiated contralateral muscles, implying that dystrophin-competent satellite cell fusion was not a significant factor in the observed conversion. A longitudinal expansion of the cytoplasmic domain of the original dystrophin-competent myonuclei during growth could explain the observed conversion phenomenon

  4. An optimized histochemical method to assess skeletal muscle glycogen and lipid stores reveals two metabolically distinct populations of type I muscle fibers

    DEFF Research Database (Denmark)

    Prats Gavalda, Clara; Gomez-Cabello, Alba; Nordby, Pernille;

    2013-01-01

    Skeletal muscle energy metabolism has been a research focus of physiologists for more than a century. Yet, how the use of intramuscular carbohydrate and lipid energy stores are coordinated during different types of exercise remains a subject of debate. Controversy arises from contradicting data...... associated proteins, Bodipy-493/503 should be the dye of choice, since oil red O creates precipitates on the lipid droplets blocking the light. In order to increase the specificity of glycogen stain, an antibody against glycogen is used. The resulting method reveals the existence of two metabolically...... preservation of muscle energy stores, air drying cryosections or cycles of freezing-thawing need to be avoided. Furthermore, optimization of the imaging settings in order to specifically image intracellular lipid droplets stained with oil red O or Bodipy-493/503 is shown. When co-staining lipid droplets with...

  5. Darwin taxonomist: Barnacles and shell burrowing barnacles Darwin taxónomo: cirrípedos y cirrípedos perforadores de conchas

    OpenAIRE

    JUAN CARLOS CASTILLA

    2009-01-01

    This bibliographic review revisits circumstances in which the wharf, shell burrowing barnacle, Cryptophialus minutus, was first collected by Charles Darwin in southern Chile, in 1836. Further, explores how its collection marked Darwin's taxonomical interest in Cirripedia. A short review analyzes the initial number of extant species of Cirripedia, as described by Darwin and the present situation, with emphasis on recent collections of C. minutus in the southern tip of South America.Esta revisi...

  6. Electrical characteristics of rat skeletal muscle in immaturity, adulthood and after sciatic nerve injury, and their relation to muscle fiber size

    International Nuclear Information System (INIS)

    Localized impedance methods can provide useful approaches for assessing neuromuscular disease. The mechanism of these impedance changes remains, however, uncertain. In order to begin to understand the relation of muscle pathology to surface impedance values, 8 immature rats, 12 mature rats and 8 mature rats that had undergone sciatic crush were killed. Measurement was made on tissue from the gastrocnemius muscle from each animal in an impedance cell, and the conductivity and relative permittivity of the tissue were calculated in both the longitudinal and transverse directions for frequencies of 2 kHz to 1 MHz. In addition, quantitative histological analysis was performed on the tissue. Significant elevations in transverse conductivity and transverse relative permittivity were found with animal growth, but longitudinal values showed no difference. After sciatic crush, both transverse and longitudinal conductivity increased significantly, with no change in the relative permittivity in either direction. The frequency dependence of the values also changed after nerve injury. In the healthy animals, there was a strong linear relation between measured conductivity and relative permittivity with cell area, but not for the sciatic crush animals. These results provide a first step toward developing a comprehensive understanding of how the electrical properties of muscle alter in neuromuscular disease states

  7. Comparison of blood variables, fiber intensity, and muscle metabolites in hot-boned muscles from electrical- and gas-stunned broilers.

    Science.gov (United States)

    Xu, L; Yue, H Y; Wu, S G; Zhang, H J; Ji, F; Zhang, L; Qi, G H

    2011-08-01

    The aim of this study was to compare the effects of gas stunning (GS) and electrical stunning (ES) on energy metabolism in Arbor Acres broilers. Thirty-six birds were slaughtered without stunning (control) or after stunning with the following treatments: 40% CO(2) + 21% O(2) + N(2) (G40%); 60% CO(2) + 21% O(2) + N(2) (G60%); 35 V, 47 mA, 400 Hz (E35V); 50 V, 67 mA, 160 Hz (E50V); and 65 V, 86 mA, 1,000 Hz (E65V). Muscle samples were obtained from the pectoralis major (breast) and tibialis anterior (leg) muscles in ambient temperature within 45 min postmortem and stored at -80°C. Blood pH decreased consistently with GS (G40% and G60%) compared with ES and the control (P 0.05) from ES at low current (E35V) in either breast or leg muscle. In conclusion, no essential difference in energy metabolism was found in broilers stunned with ES and GS when ES was based on low current and high frequency and GS was based on hypercapnic moderate oxygenation. This study indicated that G40% was potentially a superior stunning variable. PMID:21753223

  8. Growth associated protein 43 is expressed in skeletal muscle fibers and is localized in proximity of mitochondria and calcium release units.

    Directory of Open Access Journals (Sweden)

    Simone Guarnieri

    Full Text Available The neuronal Growth Associated Protein 43 (GAP43, also known as B-50 or neuromodulin, is involved in mechanisms controlling pathfinding and branching of neurons during development and regeneration. For many years this protein was classified as neuron-specific, but recent evidences suggest that a GAP43 is expressed in the nervous system not only in neurons, but also in glial cells, and b probably it is present also in other tissues. In particular, its expression was revealed in muscles from patients affected by various myopathies, indicating that GAP43 can no-longer considered only as a neuron-specific molecule. We have investigated the expression and subcellular localization of GAP43 in mouse satellite cells, myotubes, and adult muscle (extensor digitorum longus or EDL using Western blotting, immuno-fluorescence combined to confocal microscopy and electron microscopy. Our in vitro results indicated that GAP43 is indeed expressed in both myoblasts and differentiating myotubes, and its cellular localization changes dramatically during maturation: in myoblasts the localization appeared to be mostly nuclear, whereas with differentiation the protein started to display a sarcomeric-like pattern. In adult fibers, GAP43 expression was evident with the protein labeling forming (in longitudinal views a double cross striation reminiscent of the staining pattern of other organelles, such as calcium release units (CRUs and mitochondria. Double immuno-staining and experiments done in EDL muscles fixed at different sarcomere lengths, allowed us to determine the localization, from the sarcomere Z-line, of GAP43 positive foci, falling between that of CRUs and of mitochondria. Staining of cross sections added a detail to the puzzle: GAP43 labeling formed a reticular pattern surrounding individual myofibrils, but excluding contractile elements. This work leads the way to further investigation about the possible physiological and structural role of GAP43 protein in

  9. Regulation of Metabolic Signaling in Human Skeletal Muscle

    DEFF Research Database (Denmark)

    Albers, Peter Hjorth

    Regulation of glucose metabolism, despite intense research through decades, is still not clear. Skeletal muscle is highly important for maintaining glucose homeostasis. Regulation of skeletal muscle glucose metabolism is influenced by protein signaling and changes in the activity of metabolic...... enzymes. Skeletal muscle consists of thousands of muscle fibers. These fibers can roughly be classified into type I and type II muscle fibers. The overall aim of this PhD thesis was to investigate the effect of insulin and exercise on human muscle fiber type specific metabolic signaling. The importance of...... biopsies, single muscle fibers were dissected. Muscle fiber type determination was performed and fibers were pooled in groups of type I and II muscle fibers. Muscle fiber pools were investigated for regulation of signaling molecules and enzymes, involved in glucose metabolism. Irrespective of the group of...

  10. Neuronal nitric oxide synthase is dislocated in type I fibers of myalgic muscle but can recover with physical exercise training

    DEFF Research Database (Denmark)

    Jensen, L; Andersen, L L; Schrøder, H D;

    2015-01-01

    Trapezius myalgia is the most common type of chronic neck pain. While physical exercise reduces pain and improves muscle function, the underlying mechanisms remain unclear. Nitric oxide (NO) signaling is important in modulating cellular function, and a dysfunctional neuronal NO synthase (nNOS) may...... of strength training normalize these disruptions, which supports previous findings of impaired muscle oxygenation during work tasks and reduced pain following exercise....

  11. Living on the Edge: Settlement Patterns by the Symbiotic Barnacle Xenobalanus globicipitis on Small Cetaceans.

    Science.gov (United States)

    Carrillo, Juan M; Overstreet, Robin M; Raga, Juan A; Aznar, Francisco J

    2015-01-01

    The highly specialized coronulid barnacle Xenobalanus globicipitis attaches exclusively on cetaceans worldwide, but little is known about the factors that drive the microhabitat patterns on its hosts. We investigate this issue based on data on occurrence, abundance, distribution, orientation, and size of X. globicipitis collected from 242 striped dolphins (Stenella coeruleoalba) that were stranded along the Mediterranean coast of Spain. Barnacles exclusively infested the fins, particularly along the trailing edge. Occurrence, abundance, and density of X. globicipitis were significantly higher, and barnacles were significantly larger, on the caudal fin than on the flippers and dorsal fin. Barnacles were found more frequently and in greater numbers on the dorsal rather than ventral side of the caudal fin and on the central third of dorsal and ventral fluke surfaces. Nearly all examined individuals attached with their cirral fan oriented opposite to the fluke edge. We suggest that X. globicipitis may chemically recognize dolphins as a substratum, but fins, particularly the flukes, are passively selected because of creation of vortices that increase contact of cyprids with skin and early survival of these larvae at the corresponding sites. Cyprids could actively select the trailing edge and orient with the cirri facing the main direction of flow. Attachment on the dorsal side of the flukes is likely associated with asymmetrical oscillation of the caudal fin, and the main presence on the central segment of the flukes could be related to suitable water flow conditions generated by fluke performance for both settlement and nutrient filtration. PMID:26083019

  12. Response of cyprid specific genes to natural settlement cues in the barnacle Balanus (=Amphibalanus) amphitrite

    KAUST Repository

    Li, Honglei

    2010-06-01

    Quantitative real-time PCR was used to further our understanding of the molecular processes involved in the attachment and metamorphosis of larval barnacles. We report the effects of natural settlement cues (microbial biofilms and conspecific settlement-inducing factor) on the expression profiles of six barnacle cyprid specific (bcs) genes in cyprids of the barnacle Balanus (=Amphibalanus) amphitrite Darwin. Genes bcs-1 to bcs-5 all showed marked decreases in their expression between initial cyprid attachment and the completion of metamorphosis, whereas bcs-6 showed significant up-regulation. Generally, settlement cues exerted no significant effect on the decreasing trend of bcs-1 to bcs-5 expression during attachment and metamorphosis. However, the expression of bcs-6 increased prior to cyprid attachment in response to both settlement cues. This elevated expression of bcs-6 gene indicates the importance and key regulatory role of this specific gene to larval attachment and metamorphosis in this barnacle species. © 2010 Elsevier B.V. All rights reserved.

  13. Hydrocarbon pollutants alter short-term recruitment in the barnacle Balanus eburneus

    International Nuclear Information System (INIS)

    We examined barnacle recruitment to oil-treated clay tiles at two coastal and two protected sites along the Louisiana coast. Tiles exposed to crude oil and its water-soluble fraction (WSF) had diminished barnacle recruitment after 3 weeks, in comparison with non-treated tiles. Effects were most obvious at the exposed coastal sites. After a 6-week immersion, however, treatment effects were no longer consistent. In later experiments, Balanus eburneus recruitment was higher on weathered WSF tiles (exposed, and leached in seawater before immersion in the field) than on WSF tiles, but not different from control tiles. Hydrocarbons depress recruitment initially, but may be removed later by leaching or by hydrocarbon-degrading microbes, and the remaining biofilm may facilitate recruitment. While barnacle recruitment was generally higher at exposed sites, as expected from the literature, local factors caused significant variation in recruitment within exposure categories as well. Barnacles also grow to larger sizes at open-coast sites, probably because of increased water flow and planktonic food delivery. Naupliar abundances varied tremendously among sites and dates and were poor predictors of eventual recruitment. (author)

  14. Living on the Edge: Settlement Patterns by the Symbiotic Barnacle Xenobalanus globicipitis on Small Cetaceans.

    Directory of Open Access Journals (Sweden)

    Juan M Carrillo

    Full Text Available The highly specialized coronulid barnacle Xenobalanus globicipitis attaches exclusively on cetaceans worldwide, but little is known about the factors that drive the microhabitat patterns on its hosts. We investigate this issue based on data on occurrence, abundance, distribution, orientation, and size of X. globicipitis collected from 242 striped dolphins (Stenella coeruleoalba that were stranded along the Mediterranean coast of Spain. Barnacles exclusively infested the fins, particularly along the trailing edge. Occurrence, abundance, and density of X. globicipitis were significantly higher, and barnacles were significantly larger, on the caudal fin than on the flippers and dorsal fin. Barnacles were found more frequently and in greater numbers on the dorsal rather than ventral side of the caudal fin and on the central third of dorsal and ventral fluke surfaces. Nearly all examined individuals attached with their cirral fan oriented opposite to the fluke edge. We suggest that X. globicipitis may chemically recognize dolphins as a substratum, but fins, particularly the flukes, are passively selected because of creation of vortices that increase contact of cyprids with skin and early survival of these larvae at the corresponding sites. Cyprids could actively select the trailing edge and orient with the cirri facing the main direction of flow. Attachment on the dorsal side of the flukes is likely associated with asymmetrical oscillation of the caudal fin, and the main presence on the central segment of the flukes could be related to suitable water flow conditions generated by fluke performance for both settlement and nutrient filtration.

  15. Morphometric and molecular identification of individual barnacle cyprids from wild plankton

    DEFF Research Database (Denmark)

    Chen, Hsi-Nien; Høeg, Jens Thorvald; Chan, Benny K.K.

    2013-01-01

    The present study used DNA barcodes to identify individual cyprids to species. This enables accurate quantification of larvae of potential fouling species in the plankton. In addition, it explains the settlement patterns of barnacles and serves as an early warning system of unwanted immigrant...

  16. Epibiotic community on the acorn barnacle (Balanus amphitrite) from a monsoon-influenced tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Sahoo, G.; Khandeparker, L.

    The epibiotic communities (diatoms and metazoans) on the outer surfaces of the shell of the barnacle Balanus amphitrite (BSh) and its opercular valves (the scutum and tergum; BST) were investigated on a monthly basis for 1 year in a tropical monsoon-influenced...

  17. Gooseneck barnacles (Lepas spp. ingest microplastic debris in the North Pacific Subtropical Gyre

    Directory of Open Access Journals (Sweden)

    Miriam C. Goldstein

    2013-10-01

    Full Text Available Substantial quantities of small plastic particles, termed “microplastic,” have been found in many areas of the world ocean, and have accumulated in particularly high densities on the surface of the subtropical gyres. While plastic debris has been documented on the surface of the North Pacific Subtropical Gyre (NPSG since the early 1970s, the ecological implications remain poorly understood. Organisms associated with floating objects, termed the “rafting assemblage,” are an important component of the NPSG ecosystem. These objects are often dominated by abundant and fast-growing gooseneck barnacles (Lepas spp., which predate on plankton and larval fishes at the sea surface. To assess the potential effects of microplastic on the rafting community, we examined the gastrointestinal tracts of 385 barnacles collected from the NPSG for evidence of plastic ingestion. We found that 33.5% of the barnacles had plastic particles present in their gastrointestinal tract, ranging from one plastic particle to a maximum of 30 particles. Particle ingestion was positively correlated to capitulum length, and no blockage of the stomach or intestines was observed. The majority of ingested plastic was polyethylene, with polypropylene and polystyrene also present. Our results suggest that barnacle ingestion of microplastic is relatively common, with unknown trophic impacts on the rafting community and the NPSG ecosystem.

  18. Transfected muscle and non-muscle actins are differentially sorted by cultured smooth muscle and non-muscle cells

    OpenAIRE

    Mounier, N.; Perriard, J. C.; Gabbiani, Giulio; Chaponnier, Christine

    1997-01-01

    We have analyzed by immunolabeling the fate of exogenous epitope-tagged actin isoforms introduced into cultured smooth muscle and non-muscle (i.e. endothelial and epithelial) cells by transfecting the corresponding cDNAs in transient expression assays. Exogenous muscle actins did not produce obvious shape changes in transfected cells. In smooth muscle cells, transfected striated and smooth muscle actins were preferentially recruited into stress fibers. In non-muscle cells, exogenous striated ...

  19. Comparison of myosin heavy chain mRNAs, protein isoforms and fiber type proportions in the rat slow and fast muscles

    Czech Academy of Sciences Publication Activity Database

    Žurmanová, J.; Soukup, Tomáš

    2013-01-01

    Roč. 62, č. 4 (2013), s. 445-453. ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA304/08/0256; GA ČR(CZ) GA305/09/1228; GA MŠk(CZ) 7AMB12SK158; GA MŠk(CZ) LH12058 Grant ostatní: EC(XE) LSH-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Institutional support: RVO:67985823 Keywords : rat * soleus * extensor digitorum longus * myosin heavy chain isoforms * muscle gene expression * quantitative Real Time RT-PCR * SDS-PAGE * fiber type analysis Subject RIV: EA - Cell Biology Impact factor: 1.487, year: 2013

  20. Myopathic EMG findings and type II muscle fiber atrophy in patients with Lambert-Eaton myasthenic syndrome

    DEFF Research Database (Denmark)

    Crone, Clarissa; Christiansen, Ingelise; Vissing, John

    2013-01-01

    Lambert-Eaton myasthenic syndrome (LEMS) is a rare condition, which may mimic myopathy. A few reports have described that EMG in LEMS may show changes compatible with myopathy, and muscle biopsies have been described with type II as well as type I atrophy. The EMG results were, however, based on ...

  1. Muscle ceramide content in man is higher in type I than type II fibers and not influenced by glycogen content

    DEFF Research Database (Denmark)

    Nordby, P; Prats, C; Kristensen, D;

    2010-01-01

    +/- 2 mL O2 min(-1) kg(-1)) participated in the study. On the first day, one leg was glycogen-depleted (DL) by exhaustive intermittent exercise followed by low carbohydrate diet. Next day, in the overnight fasted condition, muscle biopsies were excised from vastus lateralis before and after exhaustive...

  2. The Effect of Cleft Palate Repair on Contractile Properties of Single Permeabilized Muscle Fibers From Congenitally Cleft Goats Palates

    Science.gov (United States)

    A cleft palate goat model was used to study the contractile properties of the levator veli palatini (LVP) muscle which is responsible for the movement of the soft palate. In 15-25% of patients that undergo palatoplasty, residual velopharyngeal insufficiency (VPI) remains a problem and often require...

  3. 神经肌亚体内肌纤维型的生后发育%Postnatal Development Of Histochemical Muscle Fibers in Neuromuscular Subvolumes of Rabbit

    Institute of Scientific and Technical Information of China (English)

    朱道立

    2003-01-01

    将生后2天、2周、4周、8周、12周、16周、20周、24周的家兔胫骨前肌分成前、后亚体,分别得到腓得神经主要肌分支的支配,腓深神经分支的神经分布型式随年龄增长而递降.每个肌亚体组织化学特征经由乙酰胆碱碘溶液孵育后的运动终板而确定.肌纤维可分成SO、FG、FOG和FO型.除外生后2天龄之外,前、后亚体内SO、FG、FOG肌纤维在生后2周龄、4周龄、8周龄分别约占30%左右,生后12周龄以后,在前亚体内的SO型与FOG型纤维比率下降和FG型纤维升高要超过后亚体.全部肌纤维型在生后2周龄、4周龄、8周龄、12周龄的每个肌亚体的深、中、浅部都是均匀性分布.然而,不同部位的肌纤维类型差别明显,深部以氧化型为主,而浅部则以糖酵解型为主.这种差别在生后16、20、24周龄是最典型的.两个亚体生后发育期间的每条肌纤维毛细血管数(NCF)表明SO>FO>FOG>FG型纤维和毛细血管数与肌纤维横切面积比(CCA)显示FO>SO>FOG>FG型纤维,由此指出氧供较大需求的获得是通过减小肌纤维的面积而不仅仅是依赖于增加毛细血管数量.%The mtibialis anterior of rabbits in postnatal 24,20,16,12,8,4,2 weeks and 2 days can be devided into an anterior and a posterior subvolumes are supplied by the primary branches of its muscle nerve. Innervation patterns of deep peroned nerve branch decrease with rising ages. The histochemical profile of each subvolume was determined from motor end-plates after acetylthiocholine iodide incubation. Fibers were classified as slow-twitch oxidative (SO),fast-twitch glycolytic (FG), fast-twitch oxidative-glycolytic (FOG), and fast-twitch oxidative (FO). The percentage of SO G FO three-fibers types of both subvolumes was respectively about thirty percent at postnatal 2,4,8 week ages except postnatal 2 days. After 12 week ages, SO fibers and FOG fibers decreased gradually and FG fibers increased progressively in anterior

  4. High efficiency of muscle regeneration after human myoblast clone transplantation in SCID mice.

    OpenAIRE

    Huard, J.; Verreault, S; Roy, R; Tremblay, M; Tremblay, J. P.

    1994-01-01

    SCID mouse tibialis anterior muscles were first irradiated to prevent regeneration by host myoblasts and injected with notexin to damage the muscle fibers and trigger regeneration. The muscles were then injected with roughly 5 million human myoblasts. 1 mo later, 16-33% of the normal number of muscle fibers were present in the injected muscle, because of incomplete regeneration. However, > 90% of these muscle fibers contained human dystrophin. Some newly formed muscle fibers had an accumulati...

  5. Distinct skeletal muscle fiber characteristics and gene expression in diet-sensitive versus diet-resistant obesity

    OpenAIRE

    Gerrits, Martin F.; Ghosh, Sujoy; Kavaslar, Nihan; Hill, Benjamin; Tour, Anastasia; Seifert, Erin L.; Beauchamp, Brittany; Gorman, Shelby; Stuart, Joan; Dent, Robert; McPherson, Ruth; Harper, Mary-Ellen

    2010-01-01

    Inter-individual variability in weight gain and loss under energy surfeit and deficit conditions, respectively, are well recognized but poorly understood phenomena. We documented weight loss variability in an intensively supervised clinical weight loss program and assessed skeletal muscle gene expression and phenotypic characteristics related to variable response to a 900 kcal regimen. Matched pairs of healthy, diet-compliant, obese diet-sensitive (ODS) and diet-resistant (ODR) subjects were ...

  6. Contractile properties, fiber types, and myosin isoforms in fast and slow muscles of hyperactive Japanese waltzing mice

    Czech Academy of Sciences Publication Activity Database

    Asmussen, G.; Schmalbruch, I.; Soukup, Tomáš; Pette, D.

    2003-01-01

    Roč. 184, č. 2 (2003), s. 758-766. ISSN 0014-4886 R&D Projects: GA ČR GA304/00/1653 Grant ostatní: Deutsche Forschungsgemeinschaft(DE) -; Sonderforschungsbereich(DE) 156; Schwerpunkt Muskelforschung(DE) As 74/1-2 Institutional research plan: CEZ:AV0Z5011922 Keywords : Japanese waltzing mouse * muscle contraction * myosin isoforms Subject RIV: ED - Physiology Impact factor: 3.676, year: 2003

  7. Antifouling Activity of Simple Synthetic Diterpenoids against Larvae of the Barnacle Balanus albicostatus Pilsbry

    Directory of Open Access Journals (Sweden)

    Dan-Qing Feng

    2010-11-01

    Full Text Available Five new pimarane diterpenoids 1-5 were synthesized using ent-8(14-pimarene-15R,16-diol as starting material. The structures were elucidated by means of extensive NMR and MS analysis. The antifouling activity against larval settlement of the barnacle Balanus albicostatus were evaluated using capsaicin as a positive control. Compounds 1-3 and 5 showed more potent antifouling activity than capsaicin. Compound 5, which exhibited almost the same antifouling activity as starting material, showed better stability than starting material. These compounds all showed antifouling activity in a non-toxic way against larval settlement of the barnacle B. albicostatus. Analysis of structure-activity relationships (SAR demonstrated that the substituents on the C-15 and C-16 position of pimarane diterpenoid were responsible for the antifouling activity.

  8. Phylogeny and evolution of life history strategies of the Parasitic Barnacles (Crustacea, Cirripedia, Rhizocephala)

    DEFF Research Database (Denmark)

    Glenner, Henrik; Hebsgaard, Martin Bay

    2006-01-01

    resolve the phylogenetic relationship of the order Rhizocephala and elucidate the evolution of the different life history strategies found within the Rhizocephala, we have performed the first comprehensive phylogenetic analysis of the group. Our results indicate that Rhizocephala is monophyletic with a...... filter-feeding barnacle-like ancestor. The host-infective stage, the kentrogon larva, inserted in the lifecycle of the rhizocephalan suborder, Kentrogonida, is shown to be ancestral and most likely a homologue of the juvenile stage of a conventional thoracican barnacle. The mode of host inoculation found...... in the suborder Akentrogonida, where the last pelagic larval stage directly injects the parasitic material into the heamolymph of the host is derived, and has evolved only once within the Rhizocephala. Lastly, our results show that the ancestral host for extant rhizocephalans appears to be the...

  9. An animal model for human masseter muscle: histochemical characterization of mouse, rat, rabbit, cat, dog, pig, and cow masseter muscle

    DEFF Research Database (Denmark)

    Tuxen, A; Kirkeby, S

    1990-01-01

    IM fibers, which are rarely seen in muscles other than the masticatory muscles. Therefore, pig masseter muscle might be a suitable animal model for experimental studies, such as an investigation of the distribution and diameter of fiber types in the masticatory muscles before and after orthognathic......The masseter muscle of several animal species was investigated by use of a histochemical method for the demonstration of acid-stable and alkali-stable myosin adenosine triphosphatase (ATPase). The following subdivisions of fiber types were used: Type I fibers show weak ATPase activity at pH 9.......4, type IM fibers react moderately, and type II fibers react strongly. Rat and mouse masseter muscles contained type II fibers only, as did some rabbit masseter muscles, whereas other rabbit masseter muscles possessed equal amounts of type I and II fibers. Cat and dog masseter muscles possessed both type...

  10. Marine biofouling of surfaces: morphology, and nanomechanics of Barnacle Cyprid adhesion proteins by AFM

    OpenAIRE

    Phang, In Yee

    2008-01-01

    The understanding of biointerfaces in contact with seawater is crucially important in tackling the problems of marine biofouling. Such biointerfaces involve the bioadhesives used by marine organisms to attach temporary or permanently to the surfaces immersed in water. The aim of this Thesis is to address a particular problem, i.e. barnacle adhesion, to the biointerface and the corresponding fouling process. We try to understand the first steps of the fouling process of this species, and help ...

  11. Influence of temperature on the starvation threshold of nauplii of barnacle Balanus amphitrite (Cirripedia: Thoracica)

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, D.V.; Anil, A.C.

    of starvation factor in recruitment ecology8. Among barnacles, Balanus amphitrite has gained prominence in studies relevant to larval metamorphosis, influence of different chemical cues and mechanism of their perception. Selection of this species... for his support and encouragement, Dr. A. B. Wagh for his interest in initiating this investigation. We are thankful to Dr. N. B. Bhosle, Head, MCMRD as well as other colleagues. We acknowledge the assistance extended by Mr. S Naik, Mr. N Prabhu and Mr. P...

  12. Fattening performance, metabolic indicators, and muscle composition of bulls fed fiber-rich versus starch-plus-lipid-rich concentrate diets.

    Science.gov (United States)

    Mialon, M M; Renand, G; Ortigues-Marty, I; Bauchart, D; Hocquette, J F; Mounier, L; Noël, T; Micol, D; Doreau, M

    2015-01-01

    The aim of this study was to compare the responses in fattening performance and meat composition for high-concentrate diets rich in either starch and lipids (especially omega-3 fatty acids) or fibrous by-products. A total of 140 Charolais bulls (initially 319 ± 27 kg BW) were allocated to 3 high-concentrate diets and were fattened for up to 18 mo. The diet treatments included concentrate mixtures rich in either fiber (FR; n = 56) or starch plus linseed (diets SL and SLR; n = 56 and n = 28, respectively) and barley straw. The concentrate mix was offered ad libitum in SL and FR diets but was kept isoenergetic to the FR diet in the SLR diet. Bulls were weighed every 15 d. Feed intake was measured daily. Carcass composition was assessed for all animals slaughtered at 699 ± 65 kg BW. Meat nutritional quality traits (e.g., fat content and fatty acid composition focusing on n-6 and n-3 polyunsaturated fatty acids) were measured on the longissimus thoracis, rectus abdominis, and semitendinosus muscles. Metabolic enzyme activity (phosphofructokinase, lactate dehydrogenase, and cytochrome-c oxidase) was measured on these muscles and on liver. The SL diet bulls had greater fattening performance, BW gain (P = 0.006), and efficiency for growth (P = 0.025) at an energy intake similar to that of FR diet bulls. They also had heavier carcasses with a greater proportion of fat. However, liver samples showed no difference in specific metabolic activity. Compared to bulls fed the SL diet, bulls fed SLR consumed 15% less energy and had lower BW gain (P < 0.001) but were slightly more efficient for growth (P = 0.010). They had lower carcass weight but a greater muscle-to-fat ratio. Compared to bulls fed the FR diet, SLR bulls had lower than planned NEg intake and lower BW gain but did not have differences in body composition. Compared to the FR diet, the SL diet led to a greater omega-3 fatty acid content because of a greater supply of dietary linoleic acid, especially in lean muscle

  13. Harvest locations of goose barnacles can be successfully discriminated using trace elemental signatures.

    Science.gov (United States)

    Albuquerque, Rui; Queiroga, Henrique; Swearer, Stephen E; Calado, Ricardo; Leandro, Sérgio M

    2016-01-01

    European Union regulations state that consumers must be rightfully informed about the provenance of fishery products to prevent fraudulent practices. However, mislabeling of the geographical origin is a common practice. It is therefore paramount to develop forensic methods that allow all players involved in the supply chain to accurately trace the origin of seafood. In this study, trace elemental signatures (TES) of the goose barnacle Pollicipes pollicipes, collected from ten sites along the Portuguese coast, were employed to discriminate individual's origin. Barium (Ba), boron (B), cadmium (Cd), chromium (Cr), lithium (Li), magnesium (Mg), manganese (Mn), phosphorous (P), lead (Pb), strontium (Sr) and zinc (Zn) - were quantified using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Significant differences were recorded among locations for all elements. A regularized discriminant analysis (RDA) revealed that 83% of all individuals were correctly assigned. This study shows TES can be a reliable tool to confirm the geographic origin of goose barnacles at fine spatial resolution. Although additional studies are required to ascertain the reliability of TES on cooked specimens and the temporal stability of the signature, the approach holds great promise for the management of goose barnacles fisheries, enforcement of conservation policies and assurance in accurate labeling. PMID:27292413

  14. Quantitative proteomics study of larval settlement in the barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2014-02-13

    Barnacles are major sessile components of the intertidal areas worldwide, and also one of the most dominant fouling organisms in fouling communities. Larval settlement has a crucial ecological effect not only on the distribution of the barnacle population but also intertidal community structures. However, the molecular mechanisms involved in the transition process from the larval to the juvenile stage remain largely unclear. In this study, we carried out comparative proteomic profiles of stage II nauplii, stage VI nauplii, cyprids, and juveniles of the barnacle Balanus amphitrite using label-free quantitative proteomics, followed by the measurement of the gene expression levels of candidate proteins. More than 700 proteins were identified at each stage; 80 were significantly up-regulated in cyprids and 95 in juveniles vs other stages. Specifically, proteins involved in energy and metabolism, the nervous system and signal transduction were significantly up-regulated in cyprids, whereas proteins involved in cytoskeletal remodeling, transcription and translation, cell proliferation and differentiation, and biomineralization were up-regulated in juveniles, consistent with changes associated with larval metamorphosis and tissue remodeling in juveniles. These findings provided molecular evidence for the morphological, physiological and biological changes that occur during the transition process from the larval to the juvenile stages in B. amphitrite. © 2014 Chen et al.

  15. Transcriptomic analysis of neuropeptides and peptide hormones in the barnacle Balanus amphitrite: evidence of roles in larval settlement.

    KAUST Repository

    Yan, Xing-Cheng

    2012-10-02

    The barnacle Balanus amphitrite is a globally distributed marine crustacean and has been used as a model species for intertidal ecology and biofouling studies. Its life cycle consists of seven planktonic larval stages followed by a sessile juvenile/adult stage. The transitional processes between larval stages and juveniles are crucial for barnacle development and recruitment. Although some studies have been conducted on the neuroanatomy and neuroactive substances of the barnacle, a comprehensive understanding of neuropeptides and peptide hormones remains lacking. To better characterize barnacle neuropeptidome and its potential roles in larval settlement, an in silico identification of putative transcripts encoding neuropeptides/peptide hormones was performed, based on transcriptome of the barnacle B. amphitrite that has been recently sequenced. Potential cleavage sites andstructure of mature peptides were predicted through homology search of known arthropod peptides. In total, 16 neuropeptide families/subfamilies were predicted from the barnacle transcriptome, and 14 of them were confirmed as genuine neuropeptides by Rapid Amplification of cDNA Ends. Analysis of peptide precursor structures and mature sequences showed that some neuropeptides of B. amphitrite are novel isoforms and shared similar characteristics with their homologs from insects. The expression profiling of predicted neuropeptide genes revealed that pigment dispersing hormone, SIFamide, calcitonin, and B-type allatostatin had the highest expression level in cypris stage, while tachykinin-related peptide was down regulated in both cyprids and juveniles. Furthermore, an inhibitor of proprotein convertase related to peptide maturation effectively delayed larval metamorphosis. Combination of real-time PCR results and bioassay indicated that certain neuropeptides may play an important role in cypris settlement. Overall, new insight into neuropeptides/peptide hormones characterized in this study shall

  16. 12S-lipoxygenase protein associates with α-actin fibers in human umbilical artery vascular smooth muscle cells

    International Nuclear Information System (INIS)

    The current study sets out to characterize the intracellular localization of the platelet-type 12S-lipoxygenase (12-LO), an enzyme involved in angiotensin-II induced signaling in vascular smooth muscle cells (VSMC). Immunohistochemical analysis of VSMC in vitro or human umbilical arteries in vivo showed a clear cytoplasmic localization. On immunogold electron microscopy, 12-LO was found primarily associated with cytoplasmic VSMC muscle fibrils. Upon angiotensin-II treatment of cultured VSMC, immunoprecipitated 12-LO was found bound to α-actin, a component of the cytoplasmic myofilaments. 12-LO/α-actin binding was blocked by VSMC pretreatment with the 12-LO inhibitors, baicalien or esculetine and the protein synthesis inhibitor, cycloheximide. Moreover, the binding of 12-LO to α-actin was not associated with 12-LO serine or tyrosine phosphorylation. These observations suggest a previously unrecognized angiotensin-II dependent protein interaction in VSMC through which 12-LO protein may be trafficked, for yet undiscovered purposes towards the much more abundantly expressed cytoskeletal protein α-actin

  17. Painful Unilateral Temporalis Muscle Enlargement: Reactive Masticatory Muscle Hypertrophy

    OpenAIRE

    Katsetos, Christos D.; Bianchi, Michael A.; Jaffery, Fizza; Koutzaki, Sirma; Zarella, Mark; Slater, Robert

    2013-01-01

    An instance of isolated unilateral temporalis muscle hypertrophy (reactive masticatory muscle hypertrophy with fiber type 1 predominance) confirmed by muscle biopsy with histochemical fiber typing and image analysis in a 62 year-old man is reported. The patient presented with bruxism and a painful swelling of the temple. Absence of asymmetry or other abnormalities of the craniofacial skeleton was confirmed by magnetic resonance imaging and cephalometric analyses. The patient achieved symptoma...

  18. X-ray diffraction analysis of the effects of myosin regulatory light chain phosphorylation and butanedione monoxime on skinned skeletal muscle fibers.

    Science.gov (United States)

    Yamaguchi, Maki; Kimura, Masako; Li, Zhao-Bo; Ohno, Tetsuo; Takemori, Shigeru; Hoh, Joseph F Y; Yagi, Naoto

    2016-04-15

    The phosphorylation of the myosin regulatory light chain (RLC) is an important modulator of skeletal muscle performance and plays a key role in posttetanic potentiation and staircase potentiation of twitch contractions. The structural basis for these phenomena within the filament lattice has not been thoroughly investigated. Using a synchrotron radiation source at SPring8, we obtained X-ray diffraction patterns from skinned rabbit psoas muscle fibers before and after phosphorylation of myosin RLC in the presence of myosin light chain kinase, calmodulin, and calcium at a concentration below the threshold for tension development ([Ca(2+)] = 10(-6.8)M). After phosphorylation, the first myosin layer line slightly decreased in intensity at ∼0.05 nm(-1)along the equatorial axis, indicating a partial loss of the helical order of myosin heads along the thick filament. Concomitantly, the (1,1/1,0) intensity ratio of the equatorial reflections increased. These results provide a firm structural basis for the hypothesis that phosphorylation of myosin RLC caused the myosin heads to move away from the thick filaments towards the thin filaments, thereby enhancing the probability of interaction with actin. In contrast, 2,3-butanedione monoxime (BDM), known to inhibit contraction by impeding phosphate release from myosin, had exactly the opposite effects on meridional and equatorial reflections to those of phosphorylation. We hypothesize that these antagonistic effects are due to the acceleration of phosphate release from myosin by phosphorylation and its inhibition by BDM, the consequent shifts in crossbridge equilibria leading to opposite changes in abundance of the myosin-ADP-inorganic phosphate complex state associated with helical order of thick filaments. PMID:26911280

  19. Muscle as a secretory organ

    DEFF Research Database (Denmark)

    Pedersen, Bente K

    2013-01-01

    Skeletal muscle is the largest organ in the body. Skeletal muscles are primarily characterized by their mechanical activity required for posture, movement, and breathing, which depends on muscle fiber contractions. However, skeletal muscle is not just a component in our locomotor system. Recent...... evidence has identified skeletal muscle as a secretory organ. We have suggested that cytokines and other peptides that are produced, expressed, and released by muscle fibers and exert either autocrine, paracrine, or endocrine effects should be classified as "myokines." The muscle secretome consists of...... several hundred secreted peptides. This finding provides a conceptual basis and a whole new paradigm for understanding how muscles communicate with other organs such as adipose tissue, liver, pancreas, bones, and brain. In addition, several myokines exert their effects within the muscle itself. Many...

  20. Impaired elastin fiber assembly related to reduced 67-kD elastin-binding protein in fetal lamb ductus arteriosus and in cultured aortic smooth muscle cells treated with chondroitin sulfate.

    OpenAIRE

    Hinek, A; Mecham, R. P.; Keeley, F; M. Rabinovitch

    1991-01-01

    In the fetal ductus arteriosus (DA) disruption in the assembly of elastin fibers is associated with intimal thickening and we previously reported that fetal lamb DA smooth muscle cells incubated with endothelial conditioned medium produce two-fold more chondroitin sulfate (CS) compared with aorta (Ao) cells (Boudreau, N., and M. Rabinovitch. 1991. Lab. Invest. 64:187-199). We hypothesized that CS or dermatan sulfate (DS), both N-acetylgalactosamine glycosaminoglycans (GAGs), may be similar to...

  1. Structural changes of the regulatory proteins bound to the thin filaments in skeletal muscle contraction by X-ray fiber diffraction

    International Nuclear Information System (INIS)

    In order to clarify the structural changes related to the regulation mechanism in skeletal muscle contraction, the intensity changes of thin filament-based reflections were investigated by X-ray fiber diffraction. The time course and extent of intensity changes of the first to third order troponin (TN)-associated meridional reflections with a basic repeat of 38.4 nm were different for each of these reflections. The intensity of the first and second thin filament layer lines changed in a reciprocal manner both during initial activation and during the force generation process. The axial spacings of the TN-meridional reflections decreased by ∼0.1% upon activation relative to the relaxing state and increased by ∼0.24% in the force generation state, in line with that of the 2.7-nm reflection. Ca2+-binding to TN triggered the shortening and a change in the helical symmetry of the thin filaments. Modeling of the structural changes using the intensities of the thin filament-based reflections suggested that the conformation of the globular core domain of TN altered upon activation, undergoing additional conformational changes at the tension plateau. The tail domain of TN moved together with tropomyosin during contraction. The results indicate that the structural changes of regulatory proteins bound to the actin filaments occur in two steps, the first in response to the Ca2+-binding and the second induced by actomyosin interaction

  2. Use of a fiber glass optical system to measure the contractile characteristics of a single isolated muscle cell

    Science.gov (United States)

    Chen, Chulung; Yin, Shizhuo; Li, Jiang; Yu, Francis T. S.; Cheung, Joseph Y.; Zhang, Xueqian; Lei, Xiaoxiao; Wu, Zhongkong

    1998-05-01

    Cell is the basic structural and fundamental unit of all organisms; the smallest structure capable of performing all the activities vital to life. One goal of current research interest is to learn how the muscle varies the strength of its contraction in response to electric stimuli. A wide variety of techniques have been developed to monitor the mechanical response of isolated cardiac myocytes. Some success has been reported either with the use of intact rat myocytes supported by suction micropipettes or in guinea pig myocytes adhering to glass beams. However, the usual measuring techniques exhibit destructive contact performance on live cells. They could not solve the problem, since the cell may die during or after the time-consuming attachment process at the beginning of each experiment. In contrast, a novel optical system, which consists of a microglass tube with an inner diameter the same size of a real cardiac cell, is proposed to simulate real cell's twitch process. the physical parameters of synthetic cell are well known. By comparing the dynamics of the real cell with that of the simulated cell, the twitch characteristics of the real cell can be measured.

  3. Sarcomeric dysfunction contributes to muscle weakness in facioscapulohumeral muscular dystrophy

    NARCIS (Netherlands)

    Lassche, S.; Stienen, G.J.; Irving, T.C.; Maarel, S.M. van der; Voermans, N.C.; Padberg, G.W.A.M.; Granzier, H.; Engelen, B.G. van; Ottenheijm, C.A.C.

    2013-01-01

    OBJECTIVE: To investigate whether sarcomeric dysfunction contributes to muscle weakness in facioscapulohumeral muscular dystrophy (FSHD). METHODS: Sarcomeric function was evaluated by contractile studies on demembranated single muscle fibers obtained from quadriceps muscle biopsies of 4 patients wit

  4. Expression of Calmodulin and Myosin Light Chain Kinase during Larval Settlement of the Barnacle Balanus amphitrite

    KAUST Repository

    Chen, Zhang-Fan

    2012-02-13

    Barnacles are one of the most common organisms in intertidal areas. Their life cycle includes seven free-swimming larval stages and sessile juvenile and adult stages. The transition from the swimming to the sessile stages, referred to as larval settlement, is crucial for their survivor success and subsequent population distribution. In this study, we focused on the involvement of calmodulin (CaM) and its binding proteins in the larval settlement of the barnacle, Balanus (= Amphibalanus) amphitrite. The full length of CaM gene was cloned from stage II nauplii of B. amphitrite (referred to as Ba-CaM), encoding 149 amino acid residues that share a high similarity with published CaMs in other organisms. Quantitative real-time PCR showed that Ba-CaM was highly expressed in cyprids, the stage at which swimming larvae are competent to attach and undergo metamorphosis. In situ hybridization revealed that the expressed Ba-CaM gene was localized in compound eyes, posterior ganglion and cement glands, all of which may have essential functions during larval settlement. Larval settlement assays showed that both the CaM inhibitor compound 48/80 and the CaM-dependent myosin light chain kinase (MLCK) inhibitor ML-7 effectively blocked barnacle larval settlement, whereas Ca 2+/CaM-dependent kinase II (CaMKII) inhibitors did not show any clear effects. The subsequent real-time PCR assay showed a higher expression level of Ba-MLCK gene in larval stages than in adults, suggesting an important role of Ba-MLCK gene in larval development and competency. Overall, the results suggest that CaM and CaM-dependent MLCK function during larval settlement of B. amphitrite. © 2012 Chen et al.

  5. Chenophila nanseni sp. n. (Acari: Syringophilidae parasitising the barnacle goose in Svalbard

    Directory of Open Access Journals (Sweden)

    Skoracki Maciej

    2016-03-01

    Full Text Available A new species, Chenophila nanseni sp. n., collected from covert quills of the barnacle goose Branta leucopsis (Anseriformes: Anatidae in Svalbard (Spitsbergen is described and female polymorphism is recorded in this species. In syringophilids this phenomenon was known only for representatives of the genus Stibarokris. The new species differs from the similar Ch. platyrhynchos by following features: in females of Ch. nanseni the anterior margin of the propodonotal shield is flat (vs. concave in Ch. platyrhynchos and the lengths of idiosomal setae si, f2 and ag3 in Ch. nanseni are distinctly shorter than in Ch. plathyrynchos.

  6. Role of conspecific cues and sugars in the settlement of cyprids of the barnacle, Balanus amphitrite

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.

    the settlement significantly at a lower concentration, that is 10 C08 M without any extract, whereas, D-glucose showed a reduced effect. In the present investigation, we examined whether the influence of different sugars is modulated by different proteinextracts...,A.,Dennis,B.,Julian,L.,Martin,R.,Keith,R.&James, D.W. (1994). Molecular biology of the cell, 3rd edn. New York: GarlandPublishing, Taylorand FrancisGroup. Clare, A.S. & Matsumura, K. (2000). Nature and perception of barnacle settlement pheromones. Biofouling 15, 57–71. Dobretsov...

  7. Gregarine Cephaloidophora communis mawrodiadi, 1908 in the barnacle Euraphia rhyzophorae, Oliveira, 1940 from Brazil

    Directory of Open Access Journals (Sweden)

    Lacombe Dyrce

    2002-01-01

    Full Text Available The gregarine Cephaloidophora communis was observed for the first time in Brazil in the barnacles Euraphia rhyzophorae collected in Angra dos Reis, Rio de Janeiro, Brazil, between 1990 and 1996. Histological studies showed growth phases of the parasite in specific parts of the digestive system. The intracellular forms occurred in the vacuoles of the intestinal cells. Syzygy was frequent, and the most common form following syzygy was cylindrical, with a single membrane. The cytoplasm of the gregarines was always irregular, dense, and occasionally presenting a dark stoch area.

  8. Asymmetric deformation of contracting human gastrocnemius muscle

    OpenAIRE

    Kinugasa, Ryuta; Hodgson, John A.; Edgerton, V. Reggie; Sinha, Shantanu

    2011-01-01

    Muscle fiber deformation is related to its cellular structure, as well as its architectural arrangement within the musculoskeletal system. While playing an important role in aponeurosis displacement, and efficiency of force transmission to the tendon, such deformation also provides important clues about the underlying mechanical structure of the muscle. We hypothesized that muscle fiber cross section would deform asymmetrically to satisfy the observed constant volume of muscle during a contra...

  9. Single molecule fluorescence image patterns linked to dipole orientation and axial position: application to myosin cross-bridges in muscle fibers.

    Directory of Open Access Journals (Sweden)

    Thomas P Burghardt

    Full Text Available BACKGROUND: Photoactivatable fluorescent probes developed specifically for single molecule detection extend advantages of single molecule imaging to high probe density regions of cells and tissues. They perform in the native biomolecule environment and have been used to detect both probe position and orientation. METHODS AND FINDINGS: Fluorescence emission from a single photoactivated probe captured in an oil immersion, high numerical aperture objective, produces a spatial pattern on the detector that is a linear combination of 6 independent and distinct spatial basis patterns with weighting coefficients specifying emission dipole orientation. Basis patterns are tabulated for single photoactivated probes labeling myosin cross-bridges in a permeabilized muscle fiber undergoing total internal reflection illumination. Emitter proximity to the glass/aqueous interface at the coverslip implies the dipole near-field and dipole power normalization are significant affecters of the basis patterns. Other characteristics of the basis patterns are contributed by field polarization rotation with transmission through the microscope optics and refraction by the filter set. Pattern recognition utilized the generalized linear model, maximum likelihood fitting, for Poisson distributed uncertainties. This fitting method is more appropriate for treating low signal level photon counting data than χ(2 minimization. CONCLUSIONS: Results indicate that emission dipole orientation is measurable from the intensity image except for the ambiguity under dipole inversion. The advantage over an alternative method comparing two measured polarized emission intensities using an analyzing polarizer is that information in the intensity spatial distribution provides more constraints on fitted parameters and a single image provides all the information needed. Axial distance dependence in the emission pattern is also exploited to measure relative probe position near focus. Single

  10. Phylogenetic position and evolutionary history of the turtle and whale barnacles (Cirripedia: Balanomorpha: Coronuloidea).

    Science.gov (United States)

    Hayashi, Ryota; Chan, Benny K K; Simon-Blecher, Noa; Watanabe, Hiromi; Guy-Haim, Tamar; Yonezawa, Takahiro; Levy, Yaniv; Shuto, Takuho; Achituv, Yair

    2013-04-01

    Barnacles of the superfamily Coronuloidea are obligate epibionts of various marine mammals, marine reptiles and large crustaceans. We used five molecular markers: 12S rDNA, 16S rDNA, 18S rDNA, 28S rDNA and Histone 3 to infer phylogenetic relationships among sixteen coronuloids, representing most of the recent genera of barnacles of this superfamily. Our analyses confirm the monophyly of Coronuloidea and that this superfamily and Tetraclitoidea are sister groups. The six-plated Austrobalanus clusters with these two superfamilies. Based on BEAST and ML trees, Austrobalanus is basal and sister to the Coronuloidea, but the NJ tree places Austrobalanus within the Tetraclitoidae, and in the MP tree it is sister to both Coronuloidea and Tetraclitoidae. Hence the position of Austrobalanus remains unresolved. Within the Coronuloidea we identified four clades. Chelonibia occupies a basal position within the Coronuloidea which is in agreement with previous studies. The grouping of the other clades does not conform to previous studies. Divergence time analyses show that some of the time estimates are congruent with the fossil record while some others are older, suggesting the possibility of gaps in the fossil record. PMID:23306306

  11. Massive recruitment of the barnacle Semibalanus balanoides in the Clyde Sea (Scotland, UK) in the spring of 2000

    DEFF Research Database (Denmark)

    Hansson, L.J.; Hudson, I.R.; Seddon, R.J.; Shaw, O.; Thomason, J.C.

    2003-01-01

    In April 2000 a massive recruitment of the barnacle Semibalanus balanoides was observed in the Clyde Sea. At one location 700 cyprids l(-1) of this species were recorded. This is similar to3500 times more abundant than previously recorded, and resulted in metamorphosis of some cyprids whilst still...

  12. The effects of a serine protease, Alcalase®, on the adhesives of barnacle cyprids (Balanus amphitrite)

    NARCIS (Netherlands)

    Aldred, Nick; Phang, In Yee; Conlan, Sheelagh L.; Clare, Anthony S.; Vancso, G. Julius

    2008-01-01

    Barnacles are a persistent fouling problem in the marine environment, although their effects (eg reduced fuel efficiency, increased corrosion) can be reduced through the application of antifouling or fouling-release coatings to marine structures. However, the developments of fouling-resistant coatin

  13. FORAGING BEHAVIOR AND SITE SELECTION OF BARNACLE GEESE BRANTA-LEUCOPSIS IN A TRADITIONAL AND NEWLY COLONIZED SPRING STAGING HABITAT

    NARCIS (Netherlands)

    BLACK, JM; OWEN, M

    1991-01-01

    For three weeks in May the Svalbard Barnacle Geese Branta leucopsis stop to feed on the archipelagos of the Helgeland district, up to 50 km out to sea off western Norway. However, since 1980 an increasing part of the population has moved to a newly exploited agricultural habitat closer to the mainla

  14. FUELING INCUBATION : DIFFERENTIAL USE OF BODY STORES IN ARCTIC-AND TEMPERATE-BREEDING BARNACLE GEESE (BRANTA LEUCOPSIS)

    NARCIS (Netherlands)

    Eichhorn, Goetz; van der Jeugd, Henk P.; Meijer, Harro A. J.; Drent, Rudolf H.; McWilliams, S.R.

    2010-01-01

    We compared the use of body stores in breeding Barnacle Geese (Branta leucopsis) in traditional Arctic colonies in the Barents Sea with that in recently established temperate-zone breeding colonies in the Baltic Sea and North Sea by studying female body-mass loss and use of fat and protein stores du

  15. The Roles of Sex, Innervation, and Androgen in Laryngeal Muscle of Xenopus laevis

    OpenAIRE

    Tobias, Martha L.; Marin, Melanie L.; Darcy B Kelley

    1993-01-01

    The relative contributions of innervation and androgen to three muscle fiber properties—twitch type, size, and number—were examined in the sexually dimorphic, androgen-sensitive laryngeal muscle of Xenopus laevis. In adults, the muscle contains all fast-twitch fibers in males and fast- and slow-twitch fibers in females; laryngeal muscle fibers are larger and more numerous in males than in females. Juvenile larynges are female-like in both sexes; male laryngeal muscle is subsequently masculini...

  16. PDH regulation in skeletal muscle

    DEFF Research Database (Denmark)

    Kiilerich, Kristian

    state is determined by the overall content / activity of the regulatory proteins PDH kinase (PDK), of which there are 4 isoforms, and PDH phosphatase (PDP), of which there are 2 isoforms. The overall aim of the PhD project was to elucidate 4 issues. 1: Role of muscle type in resting and exercise......-induced PDH regulation in human skeletal muscle. 2: Effect of muscle glycogen on PDH regulation in human skeletal muscle at rest and during exercise. 3: The impact of physical inactivity on PDH regulation in human skeletal muscle at rest and during exercise. 4: Elucidating the importance of PGC-1? in PDH...... regulation in mouse skeletal muscle at rest and in response to fasting and during recovery from exercise. The studies indicate that the content of PDH-E1? in human muscle follows the metabolic profile of the muscle, rather than the myosin heavy chain fiber distribution of the muscle. The larger lactate...

  17. Proportions of myosin heavy chain mRNAs, protein isoforms and fiber types in the slow and fast skeletal muscles are maintained after alterations of thyroid status in rats

    Czech Academy of Sciences Publication Activity Database

    Soukup, Tomáš; Diallo, Michael

    2015-01-01

    Roč. 64, č. 1 (2015), s. 111-118. ISSN 0862-8408 R&D Projects: GA ČR(CZ) GA304/08/0256; GA MŠk(CZ) 7AMB12SK158; GA MŠk(CZ) 7AMB14SK123; GA MŠk(CZ) EE2.3.30.0025 Grant ostatní: EC(XE) LSH-CT-2004-511978 Institutional support: RVO:67985823 Keywords : thyroid hormones * muscle gene expression * MyHC isoforms and muscle fiber types * quantitative real time RT-PCR * SDS-PAGE and 2-D Stereological analysis Subject RIV: EA - Cell Biology Impact factor: 1.293, year: 2014

  18. Congenital fiber type disproportion.

    Science.gov (United States)

    Kissiedu, Juliana; Prayson, Richard A

    2016-04-01

    Type I muscle fiber atrophy in childhood can be encountered in a variety of neuromuscular disorders. Congenital fiber type disproportion (CFTD) is one such condition which presents as a nonprogressive muscle weakness. The diagnosis is often made after excluding other differential diagnostic considerations. We present a 2-year-9-month-old full term boy who presented at 2 months with an inability to turn his head to the right. Over the next couple of years, he showed signs of muscle weakness, broad based gait and a positive Gower's sign. He had normal levels of creatine kinase and normal electromyography. A biopsy of the vastus lateralis showed a marked variation in muscle fiber type. The adenosine triphosphate (ATP)-ase stains highlighted a marked type I muscle atrophy with rare scattered atrophic type II muscle fibers. No abnormalities were observed on the nicotinamide adenine dinucleotide (NADH), succinate dehydrogenase (SDH) or cytochrome oxidase stained sections. Ragged red fibers were not present on the trichrome stain. Abnormalities of glycogen or lipid deposition were not observed on the periodic acid-Schiff or Oil-Red-O stains. Immunostaining for muscular dystrophy associated proteins showed normal staining. Ultrastructural examination showed a normal arrangement of myofilaments, and a normal number and morphology for mitochondria. A diagnosis of CFTD was made after excluding other causes of type I atrophy including congenital myopathy. The lack of specific clinical and genetic disorder associated with CFTD suggests that it is a spectrum of a disease process and represents a diagnosis of exclusion. PMID:26526626

  19. Muscle Fiber Characteristics of Beef Samples of Yanbian Yellow Cattle from Different Quality Grades%不同质量等级延边黄牛肉肌纤维的组织特性

    Institute of Scientific and Technical Information of China (English)

    羿庆燕; 董玉影; 李官浩; 刘笑笑; 梁成云

    2013-01-01

    选取36月龄延边黄牛的眼肉作为肉样,对剪切力、肌纤维组织特性及各指标的相关性进行分析,结果表明:剪切力整体呈现下降趋势,成熟时间和质量等级对剪切力影响显著(P<0.05).随成熟时间延长,肌纤维密度和肌原纤维小片化指数(MFI)增大,肌纤维直径和肌纤维面积减小,嫩度得到提高.成熟时间和质量等级对肌纤维组织特性影响显著(P<0.05),各质量等级延边黄牛肉嫩度大小为:特级1+>优一级>优二级>普通级,说明成熟对牛肉嫩度有所提高,质量等级越高牛肉嫩度越好.%The shear force and muscle fiber characteristics as well as correlation between both of ribeyes of 36-month-old Yanbian yellow cattle were analyzed.The results obtained showed that the shear force of beef ribeye exhibited an overall downward trend with postmortem aging time,and was affected by both aging time and quality grade significantly (P<0.05).Moreover,with prolonged aging time,the muscle fiber density and myofibril fragmentation index (MFI) were increased,while muscle fiber area and diameter were reduced,thereby improving the tenderness.Both aging time and quality grade had a significant impact on muscle fiber characteristics (P<0.05).Various quality grades were ranked in decreasing order of tenderness:prime 1+ > 1st choice > 2nd choice > ordinary,indicating that beef tenderness can be improved by aging and the higher quality grade,the better tenderness.

  20. Structure–function relationship of skeletal muscle provides inspiration for design of new artificial muscle

    International Nuclear Information System (INIS)

    A variety of actuator technologies have been developed to mimic biological skeletal muscle that generates force in a controlled manner. Force generation process of skeletal muscle involves complicated biophysical and biochemical mechanisms; therefore, it is impossible to replace biological muscle. In biological skeletal muscle tissue, the force generation of a muscle depends not only on the force generation capacity of the muscle fiber, but also on many other important factors, including muscle fiber type, motor unit recruitment, architecture, structure and morphology of skeletal muscle, all of which have significant impact on the force generation of the whole muscle or force transmission from muscle fibers to the tendon. Such factors have often been overlooked, but can be incorporated in artificial muscle design, especially with the discovery of new smart materials and the development of innovative fabrication and manufacturing technologies. A better understanding of the physiology and structure–function relationship of skeletal muscle will therefore benefit the artificial muscle design. In this paper, factors that affect muscle force generation are reviewed. Mathematical models used to model the structure–function relationship of skeletal muscle are reviewed and discussed. We hope the review will provide inspiration for the design of a new generation of artificial muscle by incorporating the structure–function relationship of skeletal muscle into the design of artificial muscle. (topical review)

  1. PGC-1α plays a functional role in exercise-induced mitochondrial biogenesis and angiogenesis but not fiber-type transformation in mouse skeletal muscle

    OpenAIRE

    Geng, Tuoyu; Li, Ping; Okutsu, Mitsuharu; Yin, Xinhe; Kwek, Jyeyi; ZHANG, MEI; Yan, Zhen

    2009-01-01

    Endurance exercise stimulates peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) expression in skeletal muscle, and forced expression of PGC-1α changes muscle metabolism and exercise capacity in mice. However, it is unclear if PGC-1α is indispensible for endurance exercise-induced metabolic and contractile adaptations in skeletal muscle. In this study, we showed that endurance exercise-induced expression of mitochondrial enzymes (cytochrome oxidase IV and cytochrome c) and i...

  2. Decreased specific force and power production of muscle fibers from myostatin-deficient mice are associated with a suppression of protein degradation

    OpenAIRE

    Mendias, Christopher L; Kayupov, Erdan; Bradley, Joshua R.; Brooks, Susan V.; Claflin, Dennis R.

    2011-01-01

    Myostatin (MSTN) is a member of the transforming growth factor-β superfamily of cytokines and is a negative regulator of skeletal muscle mass. Compared with MSTN+/+ mice, the extensor digitorum longus muscles of MSTN−/− mice exhibit hypertrophy, hyperplasia, and greater maximum isometric force production (Fo), but decreased specific maximum isometric force (sFo; Fo normalized by muscle cross-sectional area). The reason for the reduction in sFo was not known. Studies in myotubes indicate that ...

  3. Apparent Km of mitochondria for oxygen computed from Vmax measured in permeabilized muscle fibers is lower in water enriched in oxygen by electrolysis than injection

    Directory of Open Access Journals (Sweden)

    Zoll J

    2015-07-01

    Full Text Available Joffrey Zoll,1 Jamal Bouitbir,1 Pascal Sirvent,2 Alexis Klein,3 Antoine Charton,1,4 Liliana Jimenez,3 François R Péronnet,5 Bernard Geny,1 Ruddy Richard61Physiology Department, Faculty of Medicine and EA3072, Université de Strasbourg, Strasbourg, 2Clermont Université, Université Blaise Pascal, EA 3533, Laboratoire des Adaptations Métaboliques à l’Exercice en Conditions Physiologiques et Pathologiques, Clermont-Ferrand, 3Danone Research, Centre Daniel Carasso, Palaiseau, 4Department of Anesthesia and Critical Care and EA3072, Hôpital de Hautepierre, Université de Strasbourg, France; 5Kinesiology Department, Université de Montréal, Montréal, QC, Canada; 6Department of Sport Medicine and Functional Explorations and INRA UMR 1019, Faculty of Medicine, Université d’Auvergne, Clermont-Ferrand, FranceBackground: It has been suggested that oxygen (O2 diffusion could be favored in water enriched in O2 by a new electrolytic process because of O2 trapping in water superstructures (clathrates, which could reduce the local pressure/content relationships for O2 and facilitate O2 diffusion along PO2 gradients.Materials and methods: Mitochondrial respiration was compared in situ in saponin-skinned fibers isolated from the soleus muscles of Wistar rats, in solution enriched in O2 by injection or the electrolytic process 1 at an O2 concentration decreasing from 240 µmol/L to 10 µmol/L (132 mmHg to 5 mmHg, with glutamate–malate or N, N, N', N'-tetramethyl-p-phenylenediamine dihydrochloride (TMPD–ascorbate (with antimycin A as substrates; and 2 at increasing adenosine diphosphate (ADP concentration with glutamate–malate as substrate.Results: As expected, maximal respiration decreased with O2 concentration and, when compared to glutamate–malate, the apparent Km O2 of mitochondria for O2 was significantly lower with TMPD–ascorbate with both waters. However, when compared to the water enriched in O2 by injection, the Km O2 was

  4. Darwin taxonomist: Barnacles and shell burrowing barnacles Darwin taxónomo: cirrípedos y cirrípedos perforadores de conchas

    Directory of Open Access Journals (Sweden)

    JUAN CARLOS CASTILLA

    2009-12-01

    Full Text Available This bibliographic review revisits circumstances in which the wharf, shell burrowing barnacle, Cryptophialus minutus, was first collected by Charles Darwin in southern Chile, in 1836. Further, explores how its collection marked Darwin's taxonomical interest in Cirripedia. A short review analyzes the initial number of extant species of Cirripedia, as described by Darwin and the present situation, with emphasis on recent collections of C. minutus in the southern tip of South America.Esta revisión bibliográfica describe las circunstancias en el que el cirrípedo enano, Crypophialus minutus, perforador de conchas, fue recolectado por Charles Darwin en el sur de Chile, en 1836. Además, cómo esta recolección marcó el interés taxonómico de Darwin en Cirripedia. Se presenta una revisión resumida sobre el número inicial de especies vivas de Cirripedia, como fueron descritas por Darwin, y la situación actual, con énfasis en recolecciones recientes de C. minutus en el cono sur de Suramérica.

  5. Caught in the act: phenotypic consequences of a recent shift in feeding strategy of the shark barnacle Anelasma squalicola (Lovén, 1844)

    OpenAIRE

    Ommundsen, Anders; Noever, Christoph; Glenner, Henrik

    2016-01-01

    Anelasma squalicola is a barnacle found attached to deep-water lantern sharks of the family Etmopteridae and is the only known cirriped on fish hosts. While A. squalicola is equipped with mouth and thoracic appendages (cirri), which are used for suspension feeding in conventional barnacles, its attachment device (peduncle) appears to have evolved into a feeding device, embedded into the tissue of its host. Here we demonstrate, through comparisons of the feeding apparatuses between A. squalico...

  6. Setal morphology and cirral setation of thoracican barnacle cirri: adaptations and implications for thoracican evolution

    DEFF Research Database (Denmark)

    Chan, B.K.K.; Garm, A.; Høeg, Jens Thorvald

    2008-01-01

    volcano. Of the pedunculates, I. cumingi has the least complex setation pattern consisting of only serrulate types. This is consistent with its very simplified feeding mode and an apparent inability to discriminate between food items. Octolasmis warwickii is slightly more modified, while both P. polymerus...... and C. mitella have a more diversified setation. The balanomorphan species exhibit by far the most complex cirral setation. This is consistent with the several types of suspension feeding seen in these species, their ability to identify and sort captured food items and even to perform microfiltration...... in the mantle cavity using the setae on their three pairs of maxillipeds. Our results indicate that in thoracican barnacles, adaptations in feeding behaviour are associated with changes in the setation pattern of the cirri. In addition, the setal types and their distribution on the cirri are...

  7. Cypris settlement and dwarf male formation in the barnacle Scalpellum scalpellum

    DEFF Research Database (Denmark)

    Spremberg, U.; Høeg, Jens Thorvald; Buhl-Mortensen, L.;

    2012-01-01

    Cypris settlement and metamorphosis into dwarf males were studied in the androdioecious barnacle Scalpellum scalpellum using field collected samples from the North Sea, and experiments with laboratory reared larvae, observed with video. In the field sample, dwarf males were always situated on the...... rim of the mantle aperture and almost invariably confined to two areas (receptacles) located along the scutal plates near their contact to the terga. In the laboratory experiments, cyprids settling on the mantle rim always developed into males. Those settling elsewhere, whether on the external...... hermaphrodites. Of these 15 (29%) lacked males altogether, while 37 (71%) carried males with an average of 4.7 per hermaphrodite. On the hermaphrodite, a thin lamella along the mantle rim protects the settling and metamorphosing male from accidental damage or dislocation by the beating cirri. The cyprid gains...

  8. Biodiversity and Biogeography of Chthamalid Barnacles from the North-Eastern Pacific (Crustacea Cirripedia.

    Directory of Open Access Journals (Sweden)

    Benny K K Chan

    Full Text Available The biogeography and ecology of the species of Chthamalus present on the west coast of America are described, using data from 51 localities from Alaska to Panama, together with their zonation on the shore with respect to that of other barnacles. The species present were C. dalli, Pilsbry 1916, C. fissus, Darwin, 1854, C. anisopoma Pilsbry 1916 and four species in the C. panamensis complex. The latter are C. panamensis Pilsbry, 1916, C. hedgecocki, Pitombo & Burton, 2007, C. alani nom. nov. (formerly C. southwardorum Pitombo & Burton, 2007 and C. newmani sp. nov.. These four species were initially separated by enzyme electrophoresis. They could only be partially separated by DNA bar coding but may be separated using morphological characters.

  9. Evidence for the Involvement of p38 MAPK Activation in Barnacle Larval Settlement

    KAUST Repository

    He, Li-Sheng

    2012-10-24

    The barnacle Balanus ( = Amphibalanus) amphitrite is a major marine fouling animal. Understanding the molecular mechanism of larval settlement in this species is critical for anti-fouling research. In this study, we cloned one isoform of p38 MAPK (Bar-p38 MAPK) from this species, which shares the significant characteristic of containing a TGY motif with other species such as yeast, Drosophila and humans. The activation of p38 MAPK was detected by an antibody that recognizes the conserved dual phosphorylation sites of TGY. The results showed that phospho-p38 MAPK (pp38 MAPK) was more highly expressed at the cyprid stage, particularly in aged cyprids, in comparison to other stages, including the nauplius and juvenile stages. Immunostaining showed that Bar-p38 MAPK and pp38 MAPK were mainly located at the cyprid antennules, and especially the third and fourth segments, which are responsible for substratum exploration during settlement. The expression and localization patterns of Bar-p38 MAPK suggest its involvement in larval settlement. This postulation was also supported by the larval settlement bioassay with the p38 MAPK inhibitor SB203580. Behavioral analysis by live imaging revealed that the larvae were still capable of exploring the surface of the substratum after SB203580 treatment. This shows that the effect of p38 MAPK on larval settlement might be by regulating the secretion of permanent proteinaceous substances. Furthermore, the level of pp38 MAPK dramatically decreased after full settlement, suggesting that Bar-p38 MAPK maybe plays a role in larval settlement rather than metamorphosis. Finally, we found that Bar-p38 MAPK was highly activated when larvae confronted extracts of adult barnacle containing settlement cues, whereas larvae pre-treated with SB203580 failed to respond to the crude adult extracts.

  10. Expression of Ankrd2 in fast and slow muscles and its response to stretch are consistent with a role in slow muscle function.

    NARCIS (Netherlands)

    Mckoy, G.; Hou, Y.; Yang, S.Y.; Vega Avelaira, D.; Degens, H.; Goldspink, G.; Coulton, G.R.

    2005-01-01

    In striated muscle, the structural genes associated with muscle fiber phenotype determination as well as muscle mass accretion are regulated largely by mechanical stimuli. Passive stretch of skeletal muscle stimulates muscle growth/hypertrophy and an increased expression of slow muscle genes. We pre

  11. Muscle after spinal cord injury

    DEFF Research Database (Denmark)

    Biering-Sørensen, Bo; Kristensen, Ida Bruun; Kjaer, Michael;

    2009-01-01

    The morphological and contractile changes of muscles below the level of the lesion after spinal cord injury (SCI) are dramatic. In humans with SCI, a fiber-type transformation away from type I begins 4-7 months post-SCI and reaches a new steady state with predominantly fast glycolytic IIX fibers...

  12. Muscle Cramps

    Science.gov (United States)

    Muscle cramps are sudden, involuntary contractions or spasms in one or more of your muscles. They often occur after exercise or at night, ... to several minutes. It is a very common muscle problem. Muscle cramps can be caused by nerves ...

  13. Muscle Disorders

    Science.gov (United States)

    Your muscles help you move and help your body work. Different types of muscles have different jobs. There are many problems that can affect muscles. Muscle disorders can cause weakness, pain or even ...

  14. Muscle atrophy

    Science.gov (United States)

    Muscle wasting; Wasting; Atrophy of the muscles ... There are two types of muscle atrophy. Disuse atrophy occurs from a lack of physical activity. In most people, muscle atrophy is caused by not using the ...

  15. Ultrastructural muscle and neuro-muscular junction alterations in polymyositis

    OpenAIRE

    L. L. Babakova; O. M. Pozdnyakov

    2015-01-01

    Ultrastructural analysis of 7 biopsies from m.palmaris longus and m.deltoideus in patients with confirmed polymyositis revealed alterationand degeneration of muscle fibers and anomalies of neuro-muscular junction (NMJ). The NMJ abnormalities and following denervation ofmuscle fibers in polymyositis start with subsynaptic damages. The occurance of regeneration features in muscle fibers at any stage is characteristic for PM.

  16. Changes in ACTN3 gene expression and fiber type composition in flexor hallucis longus muscle after eight weeks progressive resistance training in Sprague-Dawley rats

    OpenAIRE

    Ali Gaeini A; Khaledi N; Fayazmilani R; Ravasi A; Sedghroohi G; Arabkari V

    2013-01-01

    Background: Alpha-actinins are located in the skeletal muscle Z-line and form actin–actin cross-links. It belongs to a highly conserved family of actin-binding proteins- the spectrin superfamily, which also contains the spectrins and dystrophin. Mammalian skeletal muscle has two isoforms: alpha-actinins-2 and alpha-actinins-3. However, the response of alpha-actinins to exercise training is little understood. This study examined the effects of 8 weeks of resistance training on muscle mas...

  17. Effects of food availability on growth and reproduction of the deep-sea pedunculate barnacle Heteralepas canci

    Science.gov (United States)

    Yasuda, Natsumi; Miyamoto, Norio; Fujiwara, Yoshihiro; Yamamoto, Tomoko; Yusa, Yoichi

    2016-02-01

    Sessile animals living on continental shelves or slopes may adjust their growth and reproduction according to temporally and spatially variable food availability, but little information is available on these animals to date. We collected the pedunculate barnacle Heteralepas canci on a continental slope at a depth of 229 m off Cape Nomamisaki in southern Japan. We developed a rearing method for the barnacles and studied their growth and reproduction at different food levels in the laboratory. A total of 136 individual H. canci were fed with Artemia salina larvae and brewer's yeast at three different food levels for 100 days. Both the growth and the ovary development were delayed when food availability was low, whereas the survival rate was lower at the high food level. In addition, an individual survived under complete starvation for 167 days. We concluded that H. canci has plastic life history traits that are adaptive for variable food availability.

  18. Differential susceptibility on myosin heavy chain isoform following eccentric-induced muscle damage

    OpenAIRE

    Choi, Seung Jun

    2014-01-01

    Based on myosin heavy chain (MHC) isoform, human skeletal muscle fibers can be categorized into three fiber types, type I, IIa, IIx fibers, and each fiber type has different characteristics. Typical characteristics are difference in force production, shortening velocity, and fatigue resistance. When the muscle is contract and stretched by a force that is greater than the force generated by the muscle, contraction-induced muscle damage frequently occurs. Several experimental models involving b...

  19. Understanding species-microplastics interactions : a laboratory study on the effects of microplastics on the Azorean barnacle, Megabalanus azoricus

    OpenAIRE

    Hentschel, Lisa-Henrike, 1987-

    2015-01-01

    Understanding the impact of microplastics on the marine environment, wildlife and humans is a complex issue. Effects of contaminated microplastics (polyvinylchloride (PVC), mean size 1.5 µm) on the Azorean barnacle (Megabalanus Azoricus) were investigated within a global research project (GAME), in which akin experiments were conducted simultaneously at seven different sites worldwide in order to obtain comparable data for a range of benthic invertebrates. During a six weeks laboratory experi...

  20. Spontaneous waves in muscle fibres

    International Nuclear Information System (INIS)

    Mechanical oscillations are important for many cellular processes, e.g. the beating of cilia and flagella or the sensation of sound by hair cells. These dynamic states originate from spontaneous oscillations of molecular motors. A particularly clear example of such oscillations has been observed in muscle fibers under non-physiological conditions. In that case, motor oscillations lead to contraction waves along the fiber. By a macroscopic analysis of muscle fiber dynamics we find that the spontaneous waves involve non-hydrodynamic modes. A simple microscopic model of sarcomere dynamics highlights mechanical aspects of the motor dynamics and fits with the experimental observations

  1. Spontaneous waves in muscle fibres

    CERN Document Server

    Gunther, Stefan; 10.1088/1367-2630/9/11/417

    2009-01-01

    Mechanical oscillations are important for many cellular processes, e.g. the beating of cilia and flagella or the sensation of sound by hair cells. These dynamic states originate from spontaneous oscillations of molecular motors. A particularly clear example of such oscillations has been observed in muscle fibers under non-physiological conditions. In that case, motor oscillations lead to contraction waves along the fiber. By a macroscopic analysis of muscle fiber dynamics we find that the spontaneous waves involve non-hydrodynamic modes. A simple microscopic model of sarcomere dynamics highlights mechanical aspects of the motor dynamics and fits with the experimental observations.

  2. Regional variations of heavy metal concentrations in tissues of barnacles from the subtropical Pacific Coast of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Paez-Osuna, F.; Bojorquez-Leyva, H.; Ruelas-Inzunza, J. [Universidad Nacional Autonoma de Mexico, Mazatlan (Mexico)

    1999-07-01

    Concentrations of Cd, Cu, Cr, Fe, Mn, Ni, Ag, Pb, and Zn in soft and hard tissues of barnacles from eight sampling sites in six harbors on the subtropical Pacific Coast of Mexico were determined by atomic absorption spectrophotometry. Some inter-regional differences in metal concentrations, especially concerning Zn, Mn, Fe, Cd, and Pb, were identified. The lowest concentrations of Cu, Cr, Fe, and Ag were observed in the barnacle populations from Ceuta Lagoon, an uncontaminated site with rural agriculture and semi-intensive shrimp farms in the surroundings. Conversely, the highest concentrations of: (1) Zn, Cu, and Ag were found in the soft tissues of Balanus eburneus from Mazatlan piers; (2) Pb, Ni, and Cd in the soft tissue of Megabalanus coccopoma from Puerto Vallarta; (3) Fe in the hard tissue of Balanus sp. from Guaymas Harbour; and (4) Mn in the hard tissue of M. coccopoma from Mazatlan Harbour. Inter-comparison of the present data indicates that the soft (mainly Cd, Cu, Pb, and Zn) and the hard (mainly for Fe and Mn) tissues are useful in detecting areas of selected metallic contaminants. Barnacles such as B. eburneus, M. coccopoma, and Fistulobalanus dentivarians appear to be convenient biomonitors for identification of coastal waters exposed to Cd, Pb, Cu, Zn, Ni, Mn, Fe, and Ag in the American region of the subtropical Pacific.

  3. Effects of Toxic Leachate from Commercial Plastics on Larval Survival and Settlement of the Barnacle Amphibalanus amphitrite.

    Science.gov (United States)

    Li, Heng-Xiang; Getzinger, Gordon J; Ferguson, P Lee; Orihuela, Beatriz; Zhu, Mei; Rittschof, Daniel

    2016-01-19

    Plastic pollution represents a major and growing global problem. It is well-known that plastics are a source of chemical contaminants to the aquatic environment and provide novel habitats for marine organisms. The present study quantified the impacts of plastic leachates from the seven categories of recyclable plastics on larval survival and settlement of barnacle Amphibalanus (=Balanus) amphitrite. Leachates from plastics significantly increased barnacle nauplii mortality at the highest tested concentrations (0.10 and 0.50 m(2)/L). Hydrophobicity (measured as surface energy) was positively correlated with mortality indicating that plastic surface chemistry may be an important factor in the effects of plastics on sessile organisms. Plastic leachates significantly inhibited barnacle cyprids settlement on glass at all tested concentrations. Settlement on plastic surfaces was significantly inhibited after 24 and 48 h, but settlement was not significantly inhibited compared to the controls for some plastics after 72-96 h. In 24 h exposure to seawater, we found larval toxicity and inhibition of settlement with all seven categories of recyclable commercial plastics. Chemical analysis revealed a complex mixture of substances released in plastic leachates. Leaching of toxic compounds from all plastics should be considered when assessing the risks of plastic pollution. PMID:26667586

  4. Stable isotopes in barnacles as a tool to understand green sea turtle (Chelonia mydas) regional movement patterns

    Science.gov (United States)

    Detjen, M.; Sterling, E.; Gómez, A.

    2015-12-01

    Sea turtles are migratory animals that travel long distances between their feeding and breeding grounds. Traditional methods for researching sea turtle migratory behavior have important disadvantages, and the development of alternatives would enhance our ability to monitor and manage these globally endangered species. Here we report on the isotope signatures in green sea-turtle (Chelonia mydas) barnacles (Platylepas sp.) and discuss their potential relevance as tools with which to study green sea turtle migration and habitat use patterns. We analyzed oxygen (δ18O) and carbon (δ13C) isotope ratios in barnacle calcite layers from specimens collected from green turtles captured at the Palmyra Atoll National Wildlife Refuge (PANWR) in the central Pacific. Carbon isotopes were not informative in this study. However, the oxygen isotope results suggest likely regional movement patterns when mapped onto a predictive oxygen isotope map of the Pacific. Barnacle proxies could therefore complement other methods in understanding regional movement patterns, informing more effective conservation policy that takes into account connectivity between populations.

  5. The role of muscle spindles in the development of the monosynaptic stretch reflex

    OpenAIRE

    Wang, Zhi; Li, LingYing; Frank, Eric

    2012-01-01

    Muscle sensory axons induce the development of specialized intrafusal muscle fibers in muscle spindles during development, but the role that the intrafusal fibers may play in the development of the central projections of these Ia sensory axons is unclear. In the present study, we assessed the influence of intrafusal fibers in muscle spindles on the formation of monosynaptic connections between Ia (muscle spindle) sensory axons and motoneurons (MNs) using two transgenic strains of mice. Deleti...

  6. Bone marrow mesenchymal cells improve muscle function in a skeletal muscle re-injury model.

    Directory of Open Access Journals (Sweden)

    Bruno M Andrade

    Full Text Available Skeletal muscle injury is the most common problem in orthopedic and sports medicine, and severe injury leads to fibrosis and muscle dysfunction. Conventional treatment for successive muscle injury is currently controversial, although new therapies, like cell therapy, seem to be promise. We developed a model of successive injuries in rat to evaluate the therapeutic potential of bone marrow mesenchymal cells (BMMC injected directly into the injured muscle. Functional and histological assays were performed 14 and 28 days after the injury protocol by isometric tension recording and picrosirius/Hematoxilin & Eosin staining, respectively. We also evaluated the presence and the fate of BMMC on treated muscles; and muscle fiber regeneration. BMMC treatment increased maximal skeletal muscle contraction 14 and 28 days after muscle injury compared to non-treated group (4.5 ± 1.7 vs 2.5 ± 0.98 N/cm2, p<0.05 and 8.4 ± 2.3 vs. 5.7 ± 1.3 N/cm2, p<0.05 respectively. Furthermore, BMMC treatment increased muscle fiber cross-sectional area and the presence of mature muscle fiber 28 days after muscle injury. However, there was no difference in collagen deposition between groups. Immunoassays for cytoskeleton markers of skeletal and smooth muscle cells revealed an apparent integration of the BMMC within the muscle. These data suggest that BMMC transplantation accelerates and improves muscle function recovery in our extensive muscle re-injury model.

  7. Patterns of distribution and abundance of the stalked barnacle (Pollicipes pollicipes) in the central and southwest coast of continental Portugal

    Science.gov (United States)

    Sousa, Alina; Jacinto, David; Penteado, Nélia; Martins, Pedro; Fernandes, Joana; Silva, Teresa; Castro, João J.; Cruz, Teresa

    2013-10-01

    The stalked barnacle Pollicipes pollicipes is a cirriped crustacean that lives on very exposed rocky shores. This barnacle is the most important economical resource on intertidal rocky shores of continental Portugal. It is highly prized as food and heavily exploited (professional and recreational fishery), but fishery data are scarce and do not estimate the real pressure upon this resource. Despite its socio-economic interest, specific regulations on this fishery are recent and different along the Portuguese coast. Four regions with different regulation can be identified: the marine reserve “Reserva Natural das Berlengas” (RNB) and the marine park “Parque Marinho Prof. Luiz Saldanha” (PMLS) (both in central Portugal); the natural park located in SW Portugal (“Parque Natural do Sudoeste Alentejano e Costa Vicentina”, PNSACV); and the rest of the coast. The main objective of the present study was to study the spatial patterns of percentage cover, biomass, density and size structure of P. pollicipes in areas with different exploitation regimes, including harvested areas and no-take areas. Additionally, variability between mid shore and low shore barnacles was also analysed. Seven areas were sampled with a variable number of sites (a total of 24) randomly sampled in each area during 2011. Photographs and image analysis (percentage cover) and destructive sampling (density, biomass and size) were used. In general, percentage cover, biomass and density were higher in mid shore when compared to low shore, namely in harvested areas. Low shore barnacles had a higher proportion of adults with moderate and high commercial value, while juveniles were relatively more abundant at mid shore. There were no consistent differences in the patterns of distribution and abundance of P. pollicipes among areas subject to different exploitation regimes. The most different area was the harvested area by professional fishers in RNB, where the highest biomass within the study was

  8. Muscle structural changes in mitochondrial myopathy relate to genotype

    DEFF Research Database (Denmark)

    Olsen, David B.; Langkilde, Annika Reynberg; Ørngreen, Mette C.;

    2003-01-01

    typically not been associated with mitochondrial disease. We investigated gross and microscopic muscle morphology in thigh muscles by muscle biopsy and MRI in 16 patients with MM, and compared findings with those obtained in muscular dystrophy patients and healthy subjects. Changes of muscle architecture......It is well known that morphological changes at the cellular level occur in muscle of patients with mitochondrial myopathy (MM), but changes in muscle structure with fat infiltration and gross variation of muscle fiber size with giant fibers, normally encountered in the muscular dystrophies, have...

  9. Changes of macromolecular organizations in nonjunctional sarcolemmas after cross—innervation—a study of fast—and slow—twitch muscle fiberes in rats

    Institute of Scientific and Technical Information of China (English)

    LUJINANLI; TIEFENGZHANG; 等

    1995-01-01

    The purpose of the present study was to analyse the changes of macromolecular organizations in nonjunctional sarcolemmas of different types of skeletal muscle fibres after cross-innervation.In normal rate the mean density of square arrays(6nm particles organized in orthogonal of square arrays(6nm particles organized in othogonal arrays)was 9.02/μm2 for the nonjunctional sarcolemmas of fast-twitch extensor digitorum longus(control EDL,CE)muscle fibres and 0.34/μm2 for the nunjunctional sarcolemmas of slow-twitch soleus(control SOL,CS)muscle fibres.After cross-innervation between the fast-twitch EDL and slow-twitch SOL muscle fibres by slow and fast muscle nerves respectively for three months ,the mean density was 0.45/μm2 for the nonjunctional sarcolemmas of the operated EDL(OE)and 8.3/μm2 for the nonjunctional sarcolemmas of the operated SOL(OS).This indicates that the cross-innervation causes a reciprocal transformation of the number and distribution of such macromolecular organizations in the electrically excitable nonjunctional sarcolemmas.

  10. Impact of weightlessness on muscle function

    Science.gov (United States)

    Tischler, M. E.; Slentz, M.

    1995-01-01

    The most studied skeletal muscles which depend on gravity, "antigravity" muscles, are located in the posterior portion of the legs. Antigravity muscles are characterized generally by a different fiber type composition than those which are considered nonpostural. The gravity-dependent function of the antigravity muscles makes them particularly sensitive to weightlessness (unweighting) resulting in a substantial loss of muscle protein, with a relatively greater loss of myofibrillar (structural) proteins. Accordingly alpha-actin mRNA decreases in muscle of rats exposed to microgravity. In the legs, the soleus seems particularly responsive to the lack of weight-bearing associated with space flight. The loss of muscle protein leads to a decreased cross-sectional area of muscle fibers, particularly of the slow-twitch, oxidative (SO) ones compared to fast-twitch glycolytic (FG) or oxidative-glycolytic (FOG) fibers. In some muscles, a shift in fiber composition from SO to FOG has been reported in the adaptation to spaceflight. Changes in muscle composition with spaceflight have been associated with decreased maximal isometric tension (Po) and increased maximal shortening velocity. In terms of fuel metabolism, results varied depending on the pathway considered. Glucose uptake, in the presence of insulin, and activities of glycolytic enzymes are increased by space flight. In contrast, oxidation of fatty acids may be diminished. Oxidation of pyruvate, activity of the citric acid cycle, and ketone metabolism in muscle seem to be unaffected by microgravity.

  11. Metabolic heterogeneity in human calf muscle during maximal exercise.

    OpenAIRE

    Vandenborne, K; McCully, K; Kakihira, H; Prammer, M; Bolinger, L; Detre, J A; De Meirlier, K; Walter, G; Chance, B; Leigh, J S

    1991-01-01

    Human skeletal muscle is composed of various muscle fiber types. We hypothesized that differences in metabolism between fiber types could be detected noninvasively with 31P nuclear magnetic resonance spectroscopy during maximal exercise. This assumes that during maximal exercise all fiber types are recruited and all vary in the amount of acidosis. The calf muscles of seven subjects were studied. Two different coils were applied: an 11-cm-diameter surface coil and a five-segment meander coil. ...

  12. Muscle glycogenolysis during exercise

    DEFF Research Database (Denmark)

    Richter, Erik; Ruderman, N B; Gavras, H;

    1982-01-01

    muscle glycogenolysis during exercise: contractions principally stimulate glycogenolysis early in exercise, and a direct effect of epinephrine on muscle is needed for continued glycogenolysis. In addition, epinephrine increased oxygen consumption and glucose uptake in both resting and electrically......The interaction of epinephrine and contractions on muscle metabolism was studied in the isolated perfused rat hindquarter. Subtetanic contractions (180/min) through 20 min elicited glycogenolysis and increased phosphorylase a activity. In the soleus, a slow-twitch red muscle, these effects were...... transient, but when epinephrine at a physiological concentration (2.4 X 10(-8) M) was added to the perfusate, glycogenolysis and phosphorylase activity were sustained throughout contractions. At this high frequency of contractions, the effect of epinephrine was much smaller in the fast-twitch red fibers and...

  13. Muscle regeneration in mitochondrial myopathies

    DEFF Research Database (Denmark)

    Krag, T O; Hauerslev, S; Jeppesen, T D;

    2013-01-01

    Mitochondrial myopathies cover a diverse group of disorders in which ragged red and COX-negative fibers are common findings on muscle morphology. In contrast, muscle degeneration and regeneration, typically found in muscular dystrophies, are not considered characteristic features of mitochondrial...... myopathies. We investigated regeneration in muscle biopsies from 61 genetically well-defined patients affected by mitochondrial myopathy. Our results show that the perturbed energy metabolism in mitochondrial myopathies causes ongoing muscle regeneration in a majority of patients, and some were even affected...

  14. Expression of muscle-gene-specific isozymes of phosphorylase and creatine kinase in innervated cultured human muscle

    OpenAIRE

    1986-01-01

    Isozymes of creatine kinase and glycogen phosphorylase are excellent markers of skeletal muscle maturation. In adult innervated muscle only the muscle-gene-specific isozymes are present, whereas aneurally cultured human muscle has predominantly the fetal pattern of isozymes. We have studied the isozyme pattern of human muscle cultured in monolayer and innervated by rat embryo spinal cord explants for 20-42 d. In this culture system, large groups of innervated muscle fibers close to the ventra...

  15. The study of the optimal b-values in DTI fiber tracking in muscles around the knee%正常膝关节周围肌肉DTI纤维示踪成像b值探讨

    Institute of Scientific and Technical Information of China (English)

    时启红; 于台飞; 张玉艳

    2013-01-01

    Objective To assess the optimal b-value and reconstruction parameters for DTI and fiber tractography of the muscles around the knee. Methods Fifteen healthy volunteers(7 males, 8 females; mean age, 25. 5 years) were performed conventional MRI and DTI of knee at 3 T MRI scanner. The conventional MRI including coronal T1 WI, FS-T2 WI, sagittal T2WI, PDWI and axial T1 WI. DTI was acquired at four different b-values (400, 500, 600, 700 s/mm2). Apparent diffusion coefficient (ADC) map, exponent ADC (EADC) map, fractional anisotropy (FA) map, fractional anisotropy (FA) color-coded map were reconstructed and ADC,EADC, FA values were measured. Results The quality of fiber tract images of knee muscles were very different for different b-values. The image quality with b-value 500 was better than that of other b-values. There were no significant differences among ADC values, EADC values, and FA values for different muscles. Conclusion In conclusion, b value 500 s/mm2 was the optimal value for muscles around the knee,and there was not significant difference among DTI parameter with it in different muscles.%目的 探讨膝关节周围肌肉DTI成像的最佳b值及相关参数.方法 选取15例健康志愿者,男7例,女8例,年龄20~30岁,平均年龄25岁,行膝关节常规MR检查包括冠状T1WI、FS-T2 WI,矢状位T2 WI、PDWI及轴位T1WI,DTI(b值分别为400,500,700s/mm2)检查,重建出ADC图,eADC图,FA图及FA彩色编码图,通过DTI纤维示踪(fiber tracking)显示膝关节周围肌肉纤维束连续性和走行方向,分析比较不同b值情况下同一块肌肉肌纤维成像的清晰度与完整性,选择肌肉成像的最佳b值,并测量最佳b值时不同肌肉的ADC值、eADC值及FA值,分析不同肌肉同一b值的DTI参数有无差异.结果 不同b值在同一块肌肉中成像质量有统计学差异,b值为500s/mm2的肌肉成像质量优于b值为400s/mm2,700s/mm2时的肌肉成像质量;b值为500s/mm2时不同肌肉的ADC值、eADC值及FA值

  16. How Muscle Structure and Composition Influence Meat and Flesh Quality

    OpenAIRE

    Anne Listrat; Bénédicte Lebret; Isabelle Louveau; Thierry Astruc; Muriel Bonnet; Louis Lefaucheur; Brigitte Picard; Jérôme Bugeon

    2016-01-01

    Skeletal muscle consists of several tissues, such as muscle fibers and connective and adipose tissues. This review aims to describe the features of these various muscle components and their relationships with the technological, nutritional, and sensory properties of meat/flesh from different livestock and fish species. Thus, the contractile and metabolic types, size and number of muscle fibers, the content, composition and distribution of the connective tissue, and the content and lipid compo...

  17. Pseudohypertrophy of the calf muscles in a patient with diabetic neuropathy: a case report

    International Nuclear Information System (INIS)

    Partial or complete loss of innervation of skeletal muscle leads to muscle weakness and atrophic changes, resulting in decreased muscle volume with fatty replacement. Rarely, enlargement of the affected muscle may occur, related to two processes: true hypertrophy and pseudohypertrophy. We report CT and MR findings of the pseudohypertrophy of calf muscles, especially the soleus and gastrocnemius muscles, in a patient with diabetic neuropathy that showed increased muscle volume with diffuse fatty replacement and the presence of scanty muscle fibers

  18. Pseudohypertrophy of the calf muscles in a patient with diabetic neuropathy: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Jin; Lee, Young Hwan; Jung, Kyung Jae; Park, Young Chan; Kim, Ho Kyun; Kim, Ok Dong [School of Medicine, Catholic University of Daegu, Daegu (Korea, Republic of)

    2007-09-15

    Partial or complete loss of innervation of skeletal muscle leads to muscle weakness and atrophic changes, resulting in decreased muscle volume with fatty replacement. Rarely, enlargement of the affected muscle may occur, related to two processes: true hypertrophy and pseudohypertrophy. We report CT and MR findings of the pseudohypertrophy of calf muscles, especially the soleus and gastrocnemius muscles, in a patient with diabetic neuropathy that showed increased muscle volume with diffuse fatty replacement and the presence of scanty muscle fibers.

  19. 3D Finite Element Models of Shoulder Muscles for Computing Lines of Actions and Moment Arms

    OpenAIRE

    Webb, Joshua D.; Blemker, Silvia S.; Delp, Scott L.

    2012-01-01

    Accurate representation of musculoskeletal geometry is needed to characterize the function of shoulder muscles. Previous models of shoulder muscles have represented muscle geometry as a collection of line segments, making it difficult to account the large attachment areas, muscle-muscle interactions, and complex muscle fiber trajectories typical of shoulder muscles. To better represent shoulder muscle geometry we developed three-dimensional finite element models of the deltoid and rotator cuf...

  20. Comparative Proteome and Phosphoproteome Analyses during Cyprid Development of the Barnacle Balanus ( =Amphibalanus ) amphitrite

    KAUST Repository

    Zhang, Yu

    2010-06-04

    The barnacle Balanus amphitrite (=Amphibalanus amphitrite) is a major marine biofouling invertebrate worldwide. It has a complex life cycle during which the larva (called a nauplius) molts six times before transforming into the cyprid stage. The cyprid stage in B. amphitrite is the critical stage for the larval decision to attach and metamorphose. In this study, proteome and phosphoproteome alterations during cyprid development/aging and upon treatment with the antifouling agent butenolide were examined with a two-dimensional electrophoresis (2-DE) multiplexed fluorescent staining approach. Optimized protein separation strategies, including solution-phase isoelectric fractionation and narrow-pH-range 2-DE, were used in a proteomic analysis. Our results show that the differential regulation of the target proteins is highly dynamic on the levels of both protein expression and posttranslational modification. Two groups of proteins, stress-associated and energy metabolism-related proteins, are differentially expressed during cyprid development. Comparison of the control and treatment groups suggests that butenolide exerts its effects by sustaining the expression levels of these proteins. Altogether, our data suggest that proteins involved in stress regulation and energy metabolism play crucial roles in regulating larval attachment and metamorphosis of B. amphitrite. © 2010 American Chemical Society.

  1. siRNA transfection in larvae of the barnacle Amphibalanus amphitrite

    KAUST Repository

    Zhang, G.

    2015-06-25

    RNA interference (RNAi) provides an efficient and specific technique for functional genomic studies. Yet, no successful application of RNAi has been reported in barnacles. In this study, siRNA against p38 MAPK was synthesized and then transfected into A. amphitrite larvae at either the nauplius or cyprid stage, or at both stages. Effects of siRNA transfection on the p38 MAPK level were hardly detectable in the cyprids when they were transfected at the nauplius stage. In contrast, larvae that were transfected at the cyprid stage showed lower levels of p38 MAPK than the blank and reagent controls. However, significantly decreased levels of phosphorylated p38 MAPK (pp38 MAPK) and reduced settlement rates were observed only in ‘double transfections’, in which larvae were exposed to siRNA solution at both the nauplius and cyprid stages. A relatively longer transfection time and more larval cells directly exposed to siRNA might explain the higher efficiency of double transfection experiments.

  2. Transcriptome and proteome dynamics in larvae of the barnacle Balanus Amphitrite from the Red Sea

    KAUST Repository

    Chandramouli, Kondethimmanahalli

    2015-12-15

    Background The barnacle Balanus amphitrite is widely distributed in marine shallow and tidal waters, and has significant economic and ecological importance. Nauplii, the first larval stage of most crustaceans, are extremely abundant in the marine zooplankton. However, a lack of genome information has hindered elucidation of the molecular mechanisms of development, settlement and survival strategies in extreme marine environments. We sequenced and constructed the genome dataset for nauplii to obtain comprehensive larval genetic information. We also investigated iTRAQ-based protein expression patterns to reveal the molecular basis of nauplii development, and to gain information on larval survival strategies in the Red Sea marine environment. Results A nauplii larval transcript dataset, containing 92,117 predicted open reading frames (ORFs), was constructed and used as a reference for the proteome analysis. Genes related to translation, oxidative phosphorylation and cytoskeletal development were highly abundant. We observed remarkable plasticity in the proteome of Red Sea larvae. The proteins associated with development, stress responses and osmoregulation showed the most significant differences between the two larval populations studied. The synergistic overexpression of heat shock and osmoregulatory proteins may facilitate larval survival in intertidal habitats or in extreme environments. Conclusions We presented, for the first time, comprehensive transcriptome and proteome datasets for Red Sea nauplii. The datasets provide a foundation for future investigations focused on the survival mechanisms of other crustaceans in extreme marine environments.

  3. Population and life-stage specific sensitivities to temperature and salinity stress in barnacles.

    Science.gov (United States)

    Nasrolahi, Ali; Havenhand, Jonathan; Wrange, Anna-Lisa; Pansch, Christian

    2016-01-01

    Temperature and salinity shape the distribution and genetic structure of marine communities. Future warming and freshening will exert an additional stress to coastal marine systems. The extent to which organisms respond to these shifts will, however, be mediated by the tolerances of all life-stages and populations of species and their potential to adapt. We investigated nauplius and cypris larvae of the barnacle Balanus (Amphibalanus) improvisus from the Swedish west coast with respect to temperature (12, 20, and 28 °C) and salinity (5, 15, and 30) tolerances. Warming accelerated larval development and increased overall survival and subsequent settlement success. Nauplii developed and metamorphosed best at intermediate salinity. This was also observed in cypris larvae when the preceding nauplii stages had been reared at a salinity of 30. Direct comparisons of the present findings with those on a population from the more brackish Baltic Sea demonstrate contrasting patterns. We conclude that i) B. improvisus larvae within the Baltic region will be favoured by near-future seawater warming and freshening, that ii) salinity tolerances of larvae from the two different populations reflect salinities in their native habitats, but are nonetheless suboptimal and that iii) this species is generally highly plastic with regard to salinity. PMID:27582433

  4. Phylogeographic structure and northward range expansion in the barnacle Chthamalus fragilis

    Directory of Open Access Journals (Sweden)

    Annette F. Govindarajan

    2015-04-01

    Full Text Available The barnacle Chthamalus fragilis is found along the US Atlantic seaboard historically from the Chesapeake Bay southward, and in the Gulf of Mexico. It appeared in New England circa 1900 coincident with warming temperatures, and is now a conspicuous member of rocky intertidal communities extending through the northern shore of Cape Cod, Massachusetts. The origin of northern C. fragilis is debated. It may have spread to New England from the northern end of its historic range through larval transport by ocean currents, possibly mediated by the construction of piers, marinas, and other anthropogenic structures that provided new hard substrate habitat. Alternatively, it may have been introduced by fouling on ships originating farther south in its historic distribution. Here we examine mitochondrial cytochrome c oxidase I sequence diversity and the distribution of mitochondrial haplotypes of C. fragilis from 11 localities ranging from Cape Cod, to Tampa Bay, Florida. We found significant genetic structure between northern and southern populations. Phylogenetic analysis revealed three well-supported reciprocally monophyletic haplogroups, including one haplogroup that is restricted to New England and Virginia populations. While the distances between clades do not suggest cryptic speciation, selection and dispersal barriers may be driving the observed structure. Our data are consistent with an expansion of C. fragilis from the northern end of its mid-19th century range into Massachusetts.

  5. The role of energy composition of diet affects muscle programming and fiber recruitment, body composition, and growth trajectory in rainbow trout

    Science.gov (United States)

    Increasing production feed efficiency in aquaculture requires not only knowing the available energy for certain dietary components but understanding how they are interactively processed. For most aquaculture production muscle growth is of high priority. Nutrigenomics is a promising discipline to aug...

  6. Changes and variations of polycyclic aromatic hydrocarbon concentrations in fish, barnacles and crabs following an oil spill in a mangrove of Guanabara Bay, Southeast Brazil.

    Science.gov (United States)

    Soares-Gomes, Abílio; Neves, Roberta L; Aucélio, Ricardo; Van Der Ven, Paulo H; Pitombo, Fábio B; Mendes, Carla L T; Ziolli, Roberta L

    2010-08-01

    On April 26th, 2005, an accident caused a leak of 60,000L of Diesel Oil Type "B", freighted by train wagons upstream on a mangrove area within Guanabara Bay, Southeast Brazil. After the accident, samples from animals with different biological requirements were collected in order to monitor polycyclic aromatic hydrocarbons concentrations for the following 12months. Sessile, mobile, carnivorous, omnivorous, organic detritus feeders, planktivorous and suspension feeders were some of the attributes compared. Concentrations of PAHs did not vary in relation to different dietary habits and the best response was from the sessile suspensivorous barnacles. A background level of <50microgkg(-1) was suggested based on the reference site and on values observed in the following months after the accident. The highest values of PAH concentrations were observed in barnacles in the first month immediately after the spill, decreasing to background levels after few months. Barnacles are suggested as a sentinel species. PMID:20538307

  7. Resistance training induces qualitative changes in muscle morphology, muscle architecture, and muscle function in elderly postoperative patients

    DEFF Research Database (Denmark)

    Suetta, Charlotte; Andersen, Jesper L; Dalgas, Ulrik;

    2008-01-01

    beneficial qualitative changes in muscle fiber morphology and muscle architecture in elderly postoperative patients. In contrast, rehabilitation regimes based on functional exercises and neuromuscular electrical stimulation had no effect. The present data emphasize the importance of resistance training in......Although the negative effects of bed rest on muscle strength and muscle mass are well established, it still remains a challenge to identify effective methods to restore physical capacity of elderly patients recovering from hospitalization. The present study compared different training regimes with...... respect to muscle strength, muscle fiber size, muscle architecture, and stair walking power in elderly postoperative patients. Thirty-six patients (60-86 yr) scheduled for unilateral hip replacement surgery due to hip osteoarthritis were randomized to either 1) resistance training (RT: 3/wk x 12 wk), 2...

  8. Parallel inhibition of active force and relaxed fiber stiffness in skeletal muscle by caldesmon: implications for the pathway to force generation.

    OpenAIRE

    Brenner, B; Yu, L C; Chalovich, J. M.

    1991-01-01

    In recent hypotheses on muscle contraction, myosin cross-bridges cycle between two types of actin-bound configuration. These two configurations differ greatly in the stability of their actin-myosin complexes ("weak-binding" vs. "strong-binding"), and force generation or movement is the result of structural changes associated with the transition from the weak-binding (preforce generating) configuration to strong-binding (force producing) configuration [cf. Eisenberg, E. & Hill, T. L. (1985) Sc...

  9. Low-level laser therapy (808 nm) contributes to muscle regeneration and prevents fibrosis in rat tibialis anterior muscle after cryolesion

    OpenAIRE

    Assis, Lívia; Moretti, Ana Iochabel Soares; Abrahão, Thalita Balsamo; de Souza, Heraldo Possolo; Hamblin, Michael R.; Parizotto, Nivaldo Antonio

    2012-01-01

    Muscle regeneration is a complex phenomenon, involving replacement of damaged fibers by new muscle fibers. During this process, there is a tendency to form scar tissue or fibrosis by deposition of collagen that could be detrimental to muscle function. New therapies that could regulate fibrosis and favor muscle regeneration would be important for physical therapy. Low-level laser therapy (LLLT) has been studied for clinical treatment of skeletal muscle injuries and disorders, even though the m...

  10. Three-dimensional representation of complex muscle architectures and geometries.

    Science.gov (United States)

    Blemker, Silvia S; Delp, Scott L

    2005-05-01

    Almost all computer models of the musculoskeletal system represent muscle geometry using a series of line segments. This simplification (i) limits the ability of models to accurately represent the paths of muscles with complex geometry and (ii) assumes that moment arms are equivalent for all fibers within a muscle (or muscle compartment). The goal of this work was to develop and evaluate a new method for creating three-dimensional (3D) finite-element models that represent complex muscle geometry and the variation in moment arms across fibers within a muscle. We created 3D models of the psoas, iliacus, gluteus maximus, and gluteus medius muscles from magnetic resonance (MR) images. Peak fiber moment arms varied substantially among fibers within each muscle (e.g., for the psoas the peak fiber hip flexion moment arms varied from 2 to 3 cm, and for the gluteus maximus the peak fiber hip extension moment arms varied from 1 to 7 cm). Moment arms from the literature were generally within the range of fiber moment arms predicted by the 3D models. The models accurately predicted changes in muscle surface geometry over a 55 degrees range of hip flexion, as compared to changes in shape predicted from MR images (average errors between the model and measured surfaces were between 1.7 and 5.2 mm). This new framework for representing muscle will enhance the accuracy of computer models of the musculoskeletal system. PMID:15981866

  11. The effect of water temperature and velocity on barnacle growth: Quantifying the impact of multiple environmental stressors.

    Science.gov (United States)

    Nishizaki, Michael T; Carrington, Emily

    2015-12-01

    Organisms employ a wide array of physiological and behavioral responses in an effort to endure stressful environmental conditions. For many marine invertebrates, physiological and/or behavioral performance is dependent on physical conditions in the fluid environment. Although factors such as water temperature and velocity can elicit changes in respiration and feeding, the manner in which these processes integrate to shape growth remains unclear. In a growth experiment, juvenile barnacles (Balanus glandula) were raised in dockside, once-through flow chambers at water velocities of 2 versus 19 cm s(-1) and temperatures of 11.5 versus 14 °C. Over 37 days, growth rates (i.e., shell basal area) increased with faster water velocities and higher temperatures. Barnacles at high flows had shorter feeding appendages (i.e., cirri), suggesting that growth patterns are unlikely related to plastic responses in cirral length. A separate experiment in the field confirmed patterns of temperature- and flow-dependent growth over 41 days. Outplanted juvenile barnacles exposed to the faster water velocities (32±1 and 34±1 cm s(-1); mean±SE) and warm temperatures (16.81±0.05 °C) experienced higher growth compared to individuals at low velocities (1±1 cm s(-1)) and temperatures (13.67±0.02 °C). Growth data were consistent with estimates from a simple energy budget model based on previously measured feeding and respiration response curves that predicted peak growth at moderate temperatures (15 °C) and velocities (20-30 cm s(-1)). Low growth is expected at both low and high velocities due to lower encounter rates with suspended food particles and lower capture efficiencies respectively. At high temperatures, growth is likely limited by high metabolic costs, whereas slow growth at low temperatures may be a consequence of low oxygen availability and/or slow cirral beating and low feeding rates. Moreover, these results advocate for approaches that consider the combined effects of

  12. Muscle activity pattern dependent pain development and alleviation

    DEFF Research Database (Denmark)

    Sjøgaard, Gisela; Søgaard, Karen

    2014-01-01

    Muscle activity is for decades considered to provide health benefits irrespectively of the muscle activity pattern performed and whether it is during e.g. sports, transportation, or occupational work tasks. Accordingly, the international recommendations for public health-promoting physical activity...... during physical activities at leisure and sport the motor recruitment patterns are more dynamic including regularly relatively high muscle forces - also activating type 2 muscles fibers - as well as periods of full relaxation even of the type 1 muscle fibers. Such activity is unrelated to muscle pain...

  13. Gender differences in MR muscle tractography

    International Nuclear Information System (INIS)

    Tractography of skeletal muscle can clearly reveal the 3-dimensional course of muscle fibers, and the procedure has great potential and could open new fields for diagnostic imaging. Studying this technique for clinical application, we noticed differences in the number of visualized tracts among volunteers and among muscles in the same volunteer. To comprehend why the number of visualized tracts varied so that we could acquire consistently high quality tractography of muscle fiber, we started to examine whether differences in individual parameters affected tractography visualization. The purpose of this study was to determine whether there are gender- and age-specific differences that differentiate the muscles by gender and age in MR tractography of skeletal muscle fiber. We divided 33 healthy volunteers by gender and age among 3 groups, A (13 younger men, aged 20 to 36 years), B (11 younger women, 25 to 39 years), and C (9 older men, 50 to 69), and we obtained from each volunteer tractographs of 8 fibers, including the bilateral gastrocnemius medialis (GCM), gastrocnemius lateralis (GCL), soleus (SOL), and anterior tibialis (AT) muscles. We classified the fibers into 5 grades depending on the extent of visualized tracts and used Mann-Whitney U-test to compare scores by gender (Group A versus B) and age (Group A versus C). Muscle tracts were significantly better visualized in women than men (median total visual score, 34 versus 24, P<0.05). In particular, the SOL muscles showed better visualization in the right (4.0 in women, 1.0 in men, P<0.05) and left (3.0 in women, 1.0 in men, P<0.05). Difference by age was not significant. The GCL was the highest scored muscle in all groups. Our results suggest that group differences, especially by gender, affected visualization of tractography of muscle fiber of the calf. (author)

  14. Heterotopic neogenesis of skeletal muscle induced in the adult rat diaphragmatic peritoneum. Ultrastructural and transplantation studies

    OpenAIRE

    Drakontides, A.B.; Danon, M J; Levine, S

    1999-01-01

    During the course of a mild chemical peritonitis, new skeletal muscle fibers develop and persist over a twelve-month interval in the diaphragmatic peritoneum. Light and electron microscopic studies revealed that the ectopic fibers developed from myoblasts and myotubes to fully differentiated muscle cells in the same manner as normally situated skeletal muscle. The ectopic fibers were separated from the intrinsic muscle by dense connective tissue and an elas...

  15. A Histochemical Study of the Origin Regions of the Triceps Muscle of the Sparrow (Passer domesticus)

    OpenAIRE

    Fatime GEYİKOĞLU

    2000-01-01

    The muscle fibers in the origin regions of the triceps muscle of Passer domesticuswere characterized histochemically on the basis of their myofibrillar adenosine triphosphatase (mATPase) activity after acidic and alkaline preincubations. Muscle fibers were identified as type II (alkaline-stable/acid-labile mATPase activity) and type III (alkaline-stable/acid-stable mATPase activity). The number of type II fibers was higher in the muscle studied (83%) and this was found to be significant.

  16. Influence of UV-irradiation on the nauplius larvae of the barnacle Chthamalus sp

    International Nuclear Information System (INIS)

    The purpose of this study is to investigate the influence of UV-irradiation on the nauplius larvae of the barnacle and to use this as the basis for researching the possibility of UV-irradiation as a new method for anti-macrofouling control. The nauplius larvae in the petri dishes were exposed to UV-irradiation (λ max = 253.7 nm), then the larval states and behaviour were observed. UV-intensisties were 3.0 mW·cm-2 -7.0 mW·cm-2 and the exposure time was 15 sec -10 min. The water in the petri dishes was changed intermittently but the larvae were not fed. The results were as follows: 1) UV-irradiation may have a delayed lethal effect and metamorphosis-inhibitory effect on the nauplius larvae. 2) The lethal effect of the sum of the dosages of UV on the larvae may nearly equate each other despite differences in each UV-intensity. 3) Within ca. 72 hr, 100 % of UV-irradiated larvae were dead with the dosage of at least 672 mW·sec·cm-2 and were incapable of swimming with the dosage of at least 168 mW·sec·cm-2. 4) UV-irradiated larvae could not exuviate with the dosage of at least 246 mW·sec·cm-2 and could only exuviate with the dosage of 45 mW·sec·cm-2. 5) After UV-irradiation even the 'actively swimming' larvae may have suffered some sort of physiological damage. (author)

  17. Gut fluorescence analysis of barnacle larvae: An approach to quantify the ingested food

    Science.gov (United States)

    Gaonkar, Chetan A.; Anil, Arga Chandrashekar

    2012-10-01

    Gut fluorescence analysis can provide a snapshot of ingested food and has been employed in feeding studies of various organisms. In this study we standardised the gut fluorescence method using laboratory-reared barnacle larvae (Balanus amphitrite) fed with mono-algal diet Chaetoceros calcitrans, a unicellular diatom at a cell concentration of 2 × 105 cells ml-1. The gut fluorescence of IV-VI instar nauplii was found to be 370(±12) ng chlorophyll a larva-1 and in faecal pellets it was 224(±63) ng chlorophyll a larva-1. A phaeopigment concentration in larval gut was found to be 311(±13) ng larva-1 and in faecal pellets it was 172(±61) ng larva-1. The study also analysed larval samples collected from the field during different seasons from a tropical environment influenced by monsoons (Dona Paula bay, Goa, west coast of India), with characteristic temporal variations in phytoplankton abundance and diversity. Gut fluorescence of larvae obtained during the post-monsoon season was consistently higher when compared to the pre-monsoon season, suggesting the predominance of autotrophic forms in the larval gut during the post-monsoon season. Whereas, the low gut fluorescence obtained during the pre-monsoon season indicated the ingestion of food sources other than autotrophs. Such differences observed in the feeding behaviour of larvae could be due to differential availability of food for the larvae during different seasons and indicate the capability of larvae to feed on wide range of food sources. This study shows the value of the fluorescence method in feeding studies of planktotrophic organisms and in the evaluation of ecosystem dynamics.

  18. Toward an understanding of the molecular mechanisms of barnacle larval settlement: A comparative transcriptomic approach

    KAUST Repository

    Chen, Zhang-Fan

    2011-07-29

    Background: The barnacle Balanus amphitrite is a globally distributed biofouler and a model species in intertidal ecology and larval settlement studies. However, a lack of genomic information has hindered the comprehensive elucidation of the molecular mechanisms coordinating its larval settlement. The pyrosequencing-based transcriptomic approach is thought to be useful to identify key molecular changes during larval settlement. Methodology and Principal Findings: Using 454 pyrosequencing, we collected totally 630,845 reads including 215,308 from the larval stages and 415,537 from the adults; 23,451 contigs were generated while 77,785 remained as singletons. We annotated 31,720 of the 92,322 predicted open reading frames, which matched hits in the NCBI NR database, and identified 7,954 putative genes that were differentially expressed between the larval and adult stages. Of these, several genes were further characterized with quantitative real-time PCR and in situ hybridization, revealing some key findings: 1) vitellogenin was uniquely expressed in late nauplius stage, suggesting it may be an energy source for the subsequent non-feeding cyprid stage; 2) the locations of mannose receptors suggested they may be involved in the sensory system of cyprids; 3) 20 kDa-cement protein homologues were expressed in the cyprid cement gland and probably function during attachment; and 4) receptor tyrosine kinases were expressed higher in cyprid stage and may be involved in signal perception during larval settlement. Conclusions: Our results provide not only the basis of several new hypotheses about gene functions during larval settlement, but also the availability of this large transcriptome dataset in B. amphitrite for further exploration of larval settlement and developmental pathways in this important marine species. © 2011 Chen et al.

  19. Glycogen synthesis from lactate in a chronically active muscle

    International Nuclear Information System (INIS)

    In response to neural overactivity (pseudomyotonia), gastrocnemius muscle fibers from C57Bl/6Jdy2J/dy2J mice have different metabolic profiles compared with normal mice. A population of fibers in the fast-twitch superficial region of the dy2J gastrocnemius stores unusually high amounts of glycogen, leading to an increased glycogen storage in the whole muscle. The dy2J muscle also contains twice as much lactate as normal muscle. A [14C]lactate intraperitoneal injection leads to preferential 14C incorporation into glycogen in the dy2J muscle compared with normal muscle. To determine whether skeletal muscles were incorporating lactate into glycogen without body organ (liver, kidney) input, gastrocnemius muscles were bathed in 10 mM [14C]lactate with intact neural and arterial supply but with impeded venous return. The contralateral gastrocnemius serves as a control for body organ input. By using this in situ procedure, we demonstrate that under conditions of high lactate both normal and dy2J muscle can directly synthesize glycogen from lactate. In this case, normal whole muscle incorporates [14C] lactate into glycogen at a higher rate than dy2J whole muscle. Autoradiography, however, suggests that the high-glycogen-containing muscle fibers in the dy2J muscle incorporate lactate into glycogen at nearly four times the rate of normal or surrounding muscle fibers

  20. Locomotion as an emergent property of muscle contractile dynamics.

    Science.gov (United States)

    Biewener, Andrew A

    2016-01-01

    Skeletal muscles share many common, highly conserved features of organization at the molecular and myofilament levels, giving skeletal muscle fibers generally similar and characteristic mechanical and energetic properties; properties well described by classical studies of muscle mechanics and energetics. However, skeletal muscles can differ considerably in architectural design (fiber length, pinnation, and connective tissue organization), as well as fiber type, and how they contract in relation to the timing of neuromotor activation and in vivo length change. The in vivo dynamics of muscle contraction is, therefore, crucial to assessing muscle design and the roles that muscles play in animal movement. Architectural differences in muscle-tendon organization combined with differences in the phase of activation and resulting fiber length changes greatly affect the time-varying force and work that muscles produce, as well as the energetic cost of force generation. Intrinsic force-length and force-velocity properties of muscles, together with their architecture, also play important roles in the control of movement, facilitating rapid adjustments to changing motor demands. Such adjustments complement slower, reflex-mediated neural feedback control of motor recruitment. Understanding how individual fiber forces are integrated to whole-muscle forces, which are transmitted to the skeleton for producing and controlling locomotor movement, is therefore essential for assessing muscle design in relation to the dynamics of movement. PMID:26792341