A comparison of the mechanical properties of oesophageal striated muscle with skeletal muscles of the guinea pig

1982 ◽  
Vol 395 (4) ◽  
pp. 312-317 ◽  
Author(s):  
Anthony C. Wareham ◽  
Ian Whitmore
2020 ◽  
Author(s):  
Shiyu Luo ◽  
Qifei Li ◽  
Jasmine Lin ◽  
Quinn Murphy ◽  
Isabelle Marty ◽  
...  

Abstract SPEG, a member of the myosin light chain kinase family, is localized at the level of triad surrounding myofibrils in skeletal muscles. In humans, SPEG mutations are associated with centronuclear myopathy and cardiomyopathy. Using a striated muscle specific Speg-knockout (KO) mouse model, we have previously shown that SPEG is critical for triad maintenance and calcium handling. Here we further examined the molecular function of SPEG and characterized the effects of SPEG deficiency on triad and focal adhesion proteins. We used yeast two-hybrid assay, and identified desmin, an intermediate filament protein, to interact with SPEG and confirmed this interaction by co-immunoprecipitation. Using domain-mapping assay, we defined that Ig-like and fibronectin III domains of SPEG interact with rod domain of desmin. In skeletal muscles, SPEG depletion leads to desmin aggregates in vivo and a shift in desmin equilibrium from soluble to insoluble fraction. We also profiled the expression and localization of triadic proteins in Speg-KO mice using western blot and immunofluorescence. The amounts of RyR1 and triadin were markedly reduced, whereas DHPRα1, SERCA1, and triadin were abnormally accumulated in discrete areas of Speg-KO myofibers. In addition, Speg-KO muscles exhibited internalized vinculin and β1 integrin, both of which are critical components of the focal adhesion complex. Further, β1 integrin was abnormally accumulated in early endosomes of Speg-KO myofibers. These results demonstrate that SPEG-deficient skeletal muscles exhibit several pathological features similar to those seen in MTM1 deficiency. Defects of shared cellular pathways may underlie these structural and functional abnormalities in both types of diseases.


1964 ◽  
Vol 12 (7) ◽  
pp. 538-544 ◽  
Author(s):  
MAX WACHSTEIN ◽  
ELIZABETH MEISEL

By using an improved benzidine technique, peroxidase activity can be demonstrated in various locations in mammalian tissues. A relatively formalin resistant enzyme is found in hemoglobin and is also associated with mitochondria of striated muscle and heart. A somewhat less formalin resistant peroxidase occurs in the granules of myeloid and mast cells. A relatively formalin sensitive peroxidase is present in a number of additional locations, e.g. the acinar cells in thyroid and salivary gland, the medulla of the kidney, in hair follicles of the guinea pig skin and Kupffer cells of the liver.


BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Pabodha Hettige ◽  
Uzma Tahir ◽  
Kiisa C. Nishikawa ◽  
Matthew J. Gage

Abstract Background Individual skeletal muscles have evolved to perform specific tasks based on their molecular composition. In general, muscle fibers are characterized as either fast-twitch or slow-twitch based on their myosin heavy chain isoform profiles. This approach made sense in the early days of muscle studies when SDS-PAGE was the primary tool for mapping fiber type. However, Next Generation Sequencing tools permit analysis of the entire muscle transcriptome in a single sample, which allows for more precise characterization of differences among fiber types, including distinguishing between different isoforms of specific proteins. We demonstrate the power of this approach by comparing the differential gene expression patterns of extensor digitorum longus (EDL), psoas, and soleus from mice using high throughput RNA sequencing. Results EDL and psoas are typically classified as fast-twitch muscles based on their myosin expression pattern, while soleus is considered a slow-twitch muscle. The majority of the transcriptomic variability aligns with the fast-twitch and slow-twitch characterization. However, psoas and EDL exhibit unique expression patterns associated with the genes coding for extracellular matrix, myofibril, transcription, translation, striated muscle adaptation, mitochondrion distribution, and metabolism. Furthermore, significant expression differences between psoas and EDL were observed in genes coding for myosin light chain, troponin, tropomyosin isoforms, and several genes encoding the constituents of the Z-disk. Conclusions The observations highlight the intricate molecular nature of skeletal muscles and demonstrate the importance of utilizing transcriptomic information as a tool for skeletal muscle characterization.


Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 291 ◽  
Author(s):  
Hannah A. Nicolas ◽  
Marie-Andrée Akimenko ◽  
Frédérique Tesson

The lamin A/C (LMNA) gene codes for nuclear intermediate filaments constitutive of the nuclear lamina. LMNA has 12 exons and alternative splicing of exon 10 results in two major isoforms—lamins A and C. Mutations found throughout the LMNA gene cause a group of diseases collectively known as laminopathies, of which the type, diversity, penetrance and severity of phenotypes can vary from one individual to the other, even between individuals carrying the same mutation. The majority of the laminopathies affect cardiac and/or skeletal muscles. The underlying molecular mechanisms contributing to such tissue-specific phenotypes caused by mutations in a ubiquitously expressed gene are not yet well elucidated. This review will explore the different phenotypes observed in established models of striated muscle laminopathies and their respective contributions to advancing our understanding of cardiac and skeletal muscle-related laminopathies. Potential future directions for developing effective treatments for patients with lamin A/C mutation-associated cardiac and/or skeletal muscle conditions will be discussed.


1990 ◽  
Vol 38 (2) ◽  
pp. 257-265 ◽  
Author(s):  
L Gorza

A novel type of myosin heavy chain (MHC), called 2X, has been recently identified in type 2 fibers of rat skeletal muscles using an immunochemical approach. In the present study, the same panel of anti-MHC monoclonal antibodies was used in immunohistochemistry combined with enzyme histochemistry to identify and compare type 2X fibers in hindlimb skeletal muscles of rat, mouse, and guinea pig. Immunohistochemistry shows that 2X MHC is localized in a large subset of type 2 fibers and is co-expressed with 2A or 2B MHC in a small number of fibers. Enzyme histochemistry shows that type 2X fibers display low myosin ATPase activity after pre-incubation at pH 4.3 and high activity after paraformaldehyde pre-incubation at pH 10.4. After pre-incubation at pH 4.6, myosin ATPase shows intermediate and high activity in rat and mouse 2X fibers, respectively, whereas it is low in guinea pig 2X fibers. Succinate dehydrogenase displays moderate to high activity in 2X fibers of all species. Taken together, these staining patterns allow this novel fiber population to be distinguished from the other type 2 fibers using only enzyme histochemistry. Nevertheless, the combined use of immuno- and enzyme histochemistry prevents incorrect fiber typing due to the interspecies variability of myosin ATPase activity among the correspondent fiber types, and completely modifies the presently used classification of mouse type 2 fibers.


Sign in / Sign up

Export Citation Format

Share Document