scholarly journals Equal Force Recovery in Dysferlin-Deficient and Wild-Type Muscles Following Saponin Exposure

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Piming Zhao ◽  
Li Xu ◽  
Younss Ait-Mou ◽  
Pieter P. de Tombe ◽  
Renzhi Han
Keyword(s):  
Muscular Dystrophy ◽  
Extensor Digitorum Longus ◽  
Membrane Damage ◽  
Force Production ◽  
Slow Muscle ◽  
Wild Type ◽  
Tetanic Force ◽  
Induced Membrane ◽  
Force Recovery ◽  
Better Than

Dysferlin plays an important role in repairing membrane damage elicited by laser irradiation, and dysferlin deficiency causes muscular dystrophy and associated cardiomyopathy. Proteins such as perforin, complement component C9, and bacteria-derived cytolysins, as well as the natural detergent saponin, can form large pores on the cell membrane via complexation with cholesterol. However, it is not clear whether dysferlin plays a role in repairing membrane damage induced by pore-forming reagents. In this study, we observed that dysferlin-deficient muscles recovered the tetanic force production to the same extent as their WT counterparts following a 5-min saponin exposure (50 μg/mL). Interestingly, the slow soleus muscles recovered significantly better than the fastextensor digitorum longus(EDL) muscles. Our data suggest that dysferlin is unlikely involved in repairing saponin-induced membrane damage and that the slow muscle is more efficient than the fast muscle in repairing such damage.

A KATP channel deficiency affects resting tension, not contractile force, during fatigue in skeletal muscle

2000 ◽  
Vol 279 (5) ◽  
pp. C1351-C1358 ◽  
Author(s):  
B. Gong ◽  
T. Miki ◽  
S. Seino ◽  
J. M. Renaud
Keyword(s):  
Soleus Muscle ◽  
Force Frequency ◽  
Wild Type ◽  
Tetanic Force ◽  
Major Function ◽  
Resting Tension ◽  
Force Recovery ◽  
Fatigue Characteristics ◽  
Old Mice ◽  
Deficient Mice

The objective of this study was to determine how an ATP-sensitive K+ (KATP) channel deficiency affects the contractile and fatigue characteristics of extensor digitorum longus (EDL) and soleus muscle of 2- to 3-mo-old and 1-yr-old mice. KATP channel-deficient mice were obtained by disrupting the Kir6.2 gene that encodes for the protein forming the pore of the channel. At 2–3 mo of age, the force-frequency curve, the twitch, and the tetanic force of EDL and soleus muscle of KATPchannel-deficient mice were not significantly different from those in wild-type mice. However, the tetanic force and maximum rate of force development decreased with aging to a greater extent in EDL and soleus muscle of KATP channel-deficient mice (24–40%) than in muscle of wild-type mice (7–17%). During fatigue, the KATP channel deficiency had no effect on the decrease in tetanic force in EDL and soleus muscle, whereas it caused a significantly greater increase in resting tension when compared with muscle of wild-type mice. The recovery of tetanic force after fatigue was not affected by the deficiency in 2- to 3-mo-old mice, whereas in 1-yr-old mice, force recovery was significantly less in muscle of KATP channel-deficient than wild-type mice. It is suggested that the major function of the KATP channel during fatigue is to reduce the development of a resting tension and not to contribute to the decrease in force. It is also suggested that the KATP channel plays an important role in protecting muscle function in older mice.

Branched fibers in dystrophic mdx muscle are associated with a loss of force following lengthening contractions

2007 ◽  
Vol 293 (3) ◽  
pp. C985-C992 ◽  
Author(s):  
S. Chan ◽  
S. I. Head ◽  
J. W. Morley
Keyword(s):  
Skeletal Muscle ◽  
Muscular Dystrophy ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Force Production ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Dystrophic Muscle ◽  
Lengthening Contractions ◽  
Fast Twitch

We demonstrated that the susceptibility of skeletal muscle to injury from lengthening contractions in the dystrophin-deficient mdx mouse is directly linked with the extent of fiber branching within the muscles and that both parameters increase as the mdx animal ages. We subjected isolated extensor digitorum longus muscles to a lengthening contraction protocol of 15% strain and measured the resulting drop in force production (force deficit). We also examined the morphology of individual muscle fibers. In mdx mice 1–2 mo of age, 17% of muscle fibers were branched, and the force deficit of 7% was not significantly different from that of age-matched littermate controls. In mdx mice 6–7 mo of age, 89% of muscle fibers were branched, and the force deficit of 58% was significantly higher than the 25% force deficit of age-matched littermate controls. These data demonstrated an association between the extent of branching and the greater vulnerability to contraction-induced injury in the older fast-twitch dystrophic muscle. Our findings demonstrate that fiber branching may play a role in the pathogenesis of muscular dystrophy in mdx mice, and this could affect the interpretation of previous studies involving lengthening contractions in this animal.

scholarly journals Mass Spectrometric Profiling of Extraocular Muscle and Proteomic Adaptations in the mdx-4cv Model of Duchenne Muscular Dystrophy

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 595
Author(s):  
Stephen Gargan ◽  
Paul Dowling ◽  
Margit Zweyer ◽  
Jens Reimann ◽  
Michael Henry ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Biochemical Properties ◽  
Mass Spectrometric ◽  
Cellular Stress Response ◽  
Diaphragm Muscle ◽  
Spectrometric Analysis ◽  
Mitochondrial Enzymes ◽  
Wild Type ◽  
Potential Marker

Extraocular muscles (EOMs) represent a specialized type of contractile tissue with unique cellular, physiological, and biochemical properties. In Duchenne muscular dystrophy, EOMs stay functionally unaffected in the course of disease progression. Therefore, it was of interest to determine their proteomic profile in dystrophinopathy. The proteomic survey of wild type mice and the dystrophic mdx-4cv model revealed a broad spectrum of sarcomere-associated proteoforms, including components of the thick filament, thin filament, M-band and Z-disk, as well as a variety of muscle-specific markers. Interestingly, the mass spectrometric analysis revealed unusual expression levels of contractile proteins, especially isoforms of myosin heavy chain. As compared to diaphragm muscle, both proteomics and immunoblotting established isoform MyHC14 as a new potential marker in wild type EOMs, in addition to the previously identified isoforms MyHC13 and MyHC15. Comparative proteomics was employed to establish alterations in the protein expression profile between normal EOMs and dystrophin-lacking EOMs. The analysis of mdx-4cv EOMs identified elevated levels of glycolytic enzymes and molecular chaperones, as well as decreases in mitochondrial enzymes. These findings suggest a process of adaptation in dystrophin-deficient EOMs via a bioenergetic shift to more glycolytic metabolism, as well as an efficient cellular stress response in EOMs in dystrophinopathy.

scholarly journals Regulation of divalent metal ions to the aggregation and membrane damage of human islet amyloid polypeptide oligomers

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12815-12825
Author(s):  
Yajie Wang ◽  
Feihong Meng ◽  
Tong Lu ◽  
Chunyun Wang ◽  
Fei Li
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Membrane Damage ◽  
Islet Amyloid Polypeptide ◽  
Divalent Metal ◽  
Human Islet ◽  
Divalent Metal Ions ◽  
Islet Amyloid ◽  
Induced Membrane ◽  
Human Islet Amyloid Polypeptide

Their is a counteraction between a decrease in the disruptive ability of metal-associated oligomer species and an increase in the quantity of oligomers promoted by the metal binding in the activity of hIAPP induced membrane damage.

scholarly journals Directed Evolution of AraC for Improved Compatibility of Arabinose- and Lactose-Inducible Promoters

2007 ◽  
Vol 73 (18) ◽  
pp. 5711-5715 ◽  
Author(s):  
Sung Kuk Lee ◽  
Howard H. Chou ◽  
Brian F. Pfleger ◽  
Jack D. Newman ◽  
Yasuo Yoshikuni ◽  
...  
Keyword(s):  
Directed Evolution ◽  
Cross Talk ◽  
Biological Systems ◽  
Wild Type ◽  
Dimerization Domain ◽  
Expression Levels ◽  
Inducible Promoters ◽  
C Terminus ◽  
Increased Sensitivity ◽  
Better Than

ABSTRACT Synthetic biological systems often require multiple, independently inducible promoters in order to control the expression levels of several genes; however, cross talk between the promoters limits this ability. Here, we demonstrate the directed evolution of AraC to construct an arabinose-inducible (PBAD) system that is more compatible with IPTG (isopropyl-β-d-1-thiogalactopyranoside) induction of a lactose-inducible (Plac) system. The constructed system is 10 times more sensitive to arabinose and tolerates IPTG significantly better than the wild type. Detailed studies indicate that the AraC dimerization domain and C terminus are important for the increased sensitivity of AraC to arabinose.

Generation of Free Radicals and Enhancement of Hemin-induced Membrane Damage by a Catechol Iron Chelator in Plasmodium falciparum

2005 ◽  
Vol 5 (4) ◽  
pp. 463-471 ◽  
Author(s):  
B. Pradines . ◽  
F. Ramiandrasoa . ◽  
T. Fusai . ◽  
A. Hammadi . ◽  
M. Henry . ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Free Radicals ◽  
Membrane Damage ◽  
Iron Chelator ◽  
Induced Membrane

scholarly journals Intracellular pHluorin as Sensor for Easy Assessment of Bacteriocin-Induced Membrane-Damage in Listeria monocytogenes

2018 ◽  
Vol 9 ◽  
Author(s):  
Peter Crauwels ◽  
Leonie Schäfer ◽  
Dominik Weixler ◽  
Nadav S. Bar ◽  
Dzung B. Diep ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Membrane Damage ◽  
Induced Membrane

Repeated force production and metabolites in two medial gastrocnemius muscle compartments of the rat

1995 ◽  
Vol 79 (6) ◽  
pp. 1855-1861 ◽  
Author(s):  
C. J. De Ruiter ◽  
A. De Haan ◽  
A. J. Sargeant
Keyword(s):  
Blood Flow ◽  
Motor Nerve ◽  
Force Production ◽  
Oxidative Capacity ◽  
Medial Gastrocnemius ◽  
Train Duration ◽  
Functional Consequences ◽  
Force Recovery ◽  
The Difference ◽  
Fast Twitch

The most proximal and distal motor nerve branches in the rat medial gastrocnemius innervate discrete muscle compartments dominated by fast-twitch oxidative and fast-twitch glycolytic fibers, respectively. The functional consequences of the difference in oxidative capacity between these compartments were investigated. Wistar rats were anesthetized with pentobarbital sodium (90 mg/kg ip). Changes in force of both compartments during 21 isometric contractions (train duration 200 ms, stimulation frequency 120 Hz, 3 s between contractions) were studied in situ with and without blood flow. Without blood flow, force and phosphocreatine declined to a greater extent in the proximal than the distal compartment compared with the run with intact flow. After the protocol without blood flow, when flow was restored, the time constants for force recovery (which were closely associated to the recovery of phosphocreatine) were 37 +/- 7 (SD) (proximal compartment) and 148 +/- 20 s (distal compartment). It was concluded that the proximal compartment had a four times higher oxidative capacity and, therefore, a superior ability for repeated force production.

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