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Slow Muscles (slow + muscle)
Selected AbstractsMyogenesis and molecules, insights from zebrafish Danio rerioJOURNAL OF FISH BIOLOGY, Issue 8 2009S.-W. Chong Myogenesis is a fundamental process governing the formation of muscle in multicellular organisms. Recent studies in zebrafish Danio rerio have described the molecular events occurring during embryonic morphogenesis and have thus greatly clarified this process, helping to distinguish between the events that give rise to fast v. slow muscle. Coupled with the well-known Hedgehog signalling cascade and a wide variety of cellular processes during early development, the continual research on D. rerio slow muscle precursors has provided novel insights into their cellular behaviours in this organism. Similarly, analyses on fast muscle precursors have provided knowledge of the behaviour of a sub-set of epitheloid cells residing in the anterior domain of somites. Additionally, the findings by various groups on the roles of several molecules in somitic myogenesis have been clarified in the past year. In this study, the authors briefly review the current trends in the field of research of D. rerio trunk myogenesis. [source] Ageing influences myonuclear domain size differently in fast and slow skeletal muscle of ratsACTA PHYSIOLOGICA, Issue 1 2009N. E. Brooks Abstract Aim:, In multinucleated skeletal muscle, a myonuclear domain is the region of cytoplasm governed by one nucleus, and myofibres are mosaics of overlapping myonuclear domains. Association of ageing and myonuclear domain is important in the understanding of sarcopenia and with prevention or combating age-related muscle declines. This study examined the effects of age, fibre type and muscle on nucleo-cytoplasmic (N/C) relationships as reflecting myonuclear domain size. Methods:, The N/C was compared in fibre types of soleus and plantaris muscles from young (n = 6) and ageing (n = 8) male Fisher 344 rats. Results:, There were no significant differences in fibre type composition or cross-sectional area of the soleus across ages. The old soleus had significantly more myonuclei, resulting in a significantly smaller myonuclear domain size. The plantaris muscle showed a higher percentage of slow fibres in old compared with young fibres. There were no differences in the number of myonuclei or in myonuclear domain size between young and older animals. Conclusion:, We found muscle-specific differences in the effects of ageing on myonuclear domain, possibly as a result of reduced efficiency of the myonuclei in the slow muscles. [source] Skeletal muscle HSP72 response to mechanical unloading: influence of endurance trainingACTA PHYSIOLOGICA, Issue 4 2004D. Desplanches Abstract Aims:, It has been shown that increased contractile activity results in heat shock protein 72 (HSP72) accumulation in various skeletal muscles. By contrast, there is no consensus for muscle HSP72 response to muscle disuse for short duration (5,8 days). On the basis of a greater constitutive HSP72 expression in slow-twitch muscles we tested the hypothesis that mechanical unloading for a longer period (2 weeks) would affect this phenotype to a greater extent. Secondly, we evaluated the effects of a physiological muscle heat shock protein (HSP) enhancer (endurance training) on HSP response to unloading and muscle remodelling. Methods:, Adult male Wistar rats were assigned randomly to four groups: (1) sedentary weight-bearing; (2) hindlimb-unloaded (HU) via tail suspension for 2 week; (3) trained on a treadmill (6 week) and (4) trained 6 week and then HU for 2 week. Results:, Unloading resulted in a preferential atrophy of slow muscles [soleus (SOL), adductor longus (AL)] and a slow-to-fast fibre transition with no change in HSP72 level. HSP72 levels were significantly lower in fast muscles [extensor digitorum longus (EDL) and plantaris (PLA)], and did not change with mechanical unloading. Endurance training was accompanied by a small (SOL) or a large (EDL, PLA) increase in HSP72 level with no change in AL. Training-induced accumulation of HSP72 disappeared with subsequent unloading in the SOL and PLA whereas HSP72 content remained elevated in EDL. Conclusion:, The results of this study indicate that (1) after 2 weeks of unloading no change occurred in HSP72 protein levels of slow-twitch muscles despite a slow-to-fast fibre transition; and (2) the training-induced increase of HSP72 content in skeletal muscles did not attenuate fibre transition. [source] Convergence and extension movements affect dynamic notochord-somite interactions essential for zebrafish slow muscle morphogenesisDEVELOPMENTAL DYNAMICS, Issue 10 2007Chunyue Yin Abstract During vertebrate gastrulation, convergence and extension (C&E) movements shape and position the somites that form the fast and slow muscles. In zebrafish knypek;trilobite non-canonical Wnt mutants, defective C&E movements cause misshapen somites and reduction of slow muscle precursors, the adaxial cells. Here, we demonstrate essential roles of C&E in slow muscle morphogenesis. During segmentation, the adaxial cells change shapes and migrate laterally to form slow muscles at the myotome surface. Using confocal imaging techniques, we show that the adaxial cells undergo three-step shape changes, including dorsoventral elongation, anterior-ward rotation, and anteroposterior elongation. The adaxial cells in knypek;trilobite double mutants maintain prolonged contact with the notochord and fail to rotate anteriorly. Such a defect was suppressed by physical removal of their notochord or by introducing wild-type notochord cells into the mutant. We propose that in the double mutants, impaired C&E movements disrupt notochord development, which impedes the adaxial cell shape changes. Developmental Dynamics 236:2742,2756, 2007. © 2007 Wiley-Liss, Inc. [source] Proteomic analysis of fast and slow muscles from normal and kyphoscoliotic mice using protein arrays, 2-DE and MSPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 16 2006Marie-Catherine Le Bihan Abstract A proteomic strategy based upon the integrated use of SELDI-TOF/MS, 2-DE and MALDI-TOF/MS has been used to identify a panel of fast muscle protein markers: MLC1F, MLC3F, fast troponin,C (STNC) and slow muscle markers: MLC1SB and MLC2v. MLC3F, MLC1F and STNC were virtually absent in the physiologically ,pure slow' soleus muscle of kyphoscoliotic mutant mice compared to control BDmice, whereas MLC2v increased threefold. A SELDI-TOF/MS peak at 18,012,Da in spectra from strong anionic exchange protein array fractions of fast vastus muscle was confirmed as STNC by its specific depletion from crude extracts of vastus muscle using an anti-TNC mAb. SELDI-TOF/MS also identified MLC2F phosphorylation in crude muscle extracts after treatment with alkaline phosphatase. High probability protein identifications were achieved by SELDI-TOF/MS PMF based upon the resolution of large peptides formed by partial cleavage and high peptide coverage. When the pI from 2-D gels and molecular weight estimations from SELDI-TOF/MS were entered into the TagIdent algorithm, high probability protein identity predictions were obtained that were confirmed later by PMF. We confirm that SELDI-TOF/MS can be integrated with other proteomics techniques for the efficient analysis of protein expression changes and PTMs associated with physiological changes in skeletal muscle. [source] | ||||||||||