Propane-jet freezing of muscle fibers for freeze fracture

1984 ◽  
Vol 42 ◽  
pp. 10-11
Author(s):  
M. E. Cantino ◽  
G. H. Pollack
Keyword(s):  
Fiber Length ◽  
Muscle Fibers ◽  
Freeze Fracture ◽  
Cellular Structures ◽  
Sample Holder ◽  
Relaxing Solution ◽  
Recent Advances ◽  
Activating Solution

Recent advances in freezing techniques have intensified interest in freeze fracture for the study of nonmembranous cellular structures. We describe here a method for freezing single skinned (demembranated) muscle fibers in a dual propane jet freezing device.The freezing apparatus we used, developed by J. Gilkey and A. Staehelin (Univ. of Colo.), is based on the design by Müller. To adapt this device to studies of skinned relaxed and activated muscle fibers, we built the sample holder shown in Figure 1. The holder is separable into two parts (at the arrow) to allow mounting of fibers under relaxing solution. A modified Balzers freeze fracture support, with the back hollowed out and a groove milled in the top (figure 2) is placed between the hooks. A skinned frog semitendinosus fiber (F) is mounted over the support, between the fixed hook (right) and the moving hook (left). Fiber length is adjusted by moving the lever (L). To activate samples, the holder is removed from the bath and several drops of activating solution (relaxing solution plus calcium) are flooded over the fiber.

Contraction-induced injury to single permeabilized muscle fibers from mdx, transgenic mdx, and control mice

2000 ◽  
Vol 279 (4) ◽  
pp. C1290-C1294 ◽  
Author(s):  
Gordon S. Lynch ◽  
Jill A. Rafael ◽  
Jeffrey S. Chamberlain ◽  
John A. Faulkner
Keyword(s):  
Null Hypothesis ◽  
Fiber Length ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Extensor Digitorum ◽  
Mdx Mice ◽  
And Control ◽  
Permeabilized Fibers ◽  
Permeabilized Muscle ◽  
Sarcolemmal Integrity

Muscle fibers of mdx mice that lack dystrophin are more susceptible to contraction-induced injury, particularly when stretched. In contrast, transgenic mdx (tg -mdx) mice, which overexpress dystrophin, show no morphological or functional signs of dystrophy. Permeabilization disrupts the sarcolemma of fibers from muscles of mdx, tg- mdx, and control mice. We tested the null hypothesis stating that, after single stretches of maximally activated single permeabilized fibers, force deficits do not differ among fibers from extensor digitorum longus muscles of mdx, tg -mdx, or control mice. Fibers were maximally activated by Ca2+ (pCa 4.5) and then stretched through strains of 10%, 20%, or 30% of fiber length ( L f) at a velocity of 0.5 L f/s. Immediately after each strain, the force deficits were not different for fibers from each of the three groups of mice. When collated with studies of membrane-intact fibers in whole muscles of mdx, tg -mdx, and control mice, these results indicate that dystrophic symptoms do not arise from factors within myofibrils but, rather, from disruption of the sarcolemmal integrity that normally provides protection from contraction-induced injury.

The SR of skeletal muscle: Its structure after quick-freezing and freeze-etching, following field stimulation of single intact muscle fibers

1984 ◽  
Vol 42 ◽  
pp. 300-301
Author(s):  
J.R. Sommer ◽  
R. Nassar ◽  
N.R. Wallace
Keyword(s):  
Skeletal Muscle ◽  
Striated Muscle ◽  
Muscle Fibers ◽  
Freeze Fracture ◽  
Electron Gun ◽  
Skeletal Muscle Fibers ◽  
Quick Freezing ◽  
Intact Muscle ◽  
Similar Images ◽  
Freeze Etching

It is known that the P faces of freeze-fractured SR of fixed and cryoprotected striated muscle fibers are studded with particles, whereas the E faces remain smooth, except for two staggered rows of pits in the junctional SR (JSR) which face transverse tubules (junctional pits). Freeze-fracture after quick-freezing of native skeletal muscle provides similar images (1). We have used freeze-etching to look at the SR's structure in single intact skeletal muscle fibers (r.temporaria) without stimulation, following varied post-stimulation intervals, and in tetanus. Single intact skeletal muscle fibers were isolated and quick-frozen as previously reported (2). After quick-freezing, the fibers were transferred to a Balzers 301 device and etched for 3 minutes at -100°C, followed by unidirectional Pt evaporation with an electron gun and carbon coating.

scholarly journals Plastin 3 in X-Linked Osteoporosis: Imbalance of Ca2+-Dependent Regulation Is Equivalent to Protein Loss

2021 ◽  
Vol 8 ◽  
Author(s):  
Christopher L. Schwebach ◽  
Elena Kudryashova ◽  
Dmitri S. Kudryashov
Keyword(s):  
Osteogenesis Imperfecta ◽  
Actin Cytoskeleton ◽  
Bone Development ◽  
Genetic Disorder ◽  
Cellular Structures ◽  
Protein Loss ◽  
Pathogenic Variants ◽  
Recent Advances ◽  
Intracellular Ca

Osteogenesis imperfecta is a genetic disorder disrupting bone development and remodeling. The primary causes of osteogenesis imperfecta are pathogenic variants of collagen and collagen processing genes. However, recently variants of the actin bundling protein plastin 3 have been identified as another source of osteogenesis imperfecta. Plastin 3 is a highly conserved protein involved in several important cellular structures and processes and is controlled by intracellular Ca2+ which potently inhibits its actin-bundling activity. The precise mechanisms by which plastin 3 causes osteogenesis imperfecta remain unclear, but recent advances have contributed to our understanding of bone development and the actin cytoskeleton. Here, we review the link between plastin 3 and osteogenesis imperfecta highlighting in vitro studies and emphasizing the importance of Ca2+ regulation in the localization and functionality of plastin 3.

Application of high pressure freezing and freeze fracture to study dynamic events in plant cells

1986 ◽  
Vol 44 ◽  
pp. 234-235
Author(s):  
Stuart Craig ◽  
L.A. Staehelin
Keyword(s):  
Chemical Reactivity ◽  
Freeze Fracture ◽  
Structural Data ◽  
Cellular Structures ◽  
Limiting Factor ◽  
Specimen Preparation ◽  
Chemical Fixation ◽  
Slow Mode ◽  
Dynamic Events ◽  
Ultrarapid Freezing

Specimen preparation, in particular chemical fixation, is usually the limiting factor in studies of dynamic intracellular events by electron microscopy. The main drawbacks of chemical fixation are slow mode of action (immobilization of cellular structures requires seconds to minutes) and selectivity of chemical reactivity (different molecules are inactivated at different rates). Thus, chemical fixation is much slower than many transient cellular phenomena and cannot be used to obtain reliable structural data on such events. Ultrarapid freezing can overcome these problems. The most successful ultrarapid freezing methods are "slam" and propane jet freezing.

scholarly journals Modeling the kinematics of the canine midcostal diaphragm

2001 ◽  
Vol 280 (2) ◽  
pp. R588-R597 ◽  
Author(s):  
Maneesh R. Amancharla ◽  
Joseph R. Rodarte ◽  
Aladin M. Boriek
Keyword(s):  
Chest Wall ◽  
Muscle Fiber ◽  
Fiber Length ◽  
Lateral Displacement ◽  
Muscle Fibers ◽  
Kinematic Model ◽  
Diaphragmatic Muscle ◽  
Use Of Data

The hypotheses that the chest wall insertion (CW) is displaced laterally during inspiration and that this displacement is essential in maintaining muscle curvature of the costal diaphragmatic muscle fibers were tested. With the use of data from three dogs, caudal, lateral, and ventral displacements of CW during both quiet, spontaneous inspiration and during inspiratory efforts against an occluded airway were observed and recorded. We have developed a kinematic model of the diaphragm that incorporates these displacements. This model describes the motions of the muscle fibers and central tendon; the displacements of the midplane, muscle-tendon junction (MTJ), CW, and center of the muscle fiber-central tendon arcs are modeled as functions of muscle fiber length. In the model, the center of the fiber arcs and MTJ both move caudally parallel to the midplane during inspiration, whereas CW moves both caudally and laterally. The observed lateral displacement of CW and the observed caudal displacement of MTJ, as functions of muscle fiber length, both approximate well the theoretical displacements that would be necessary to maintain curvature of the fiber arcs. In confirming our hypotheses, we have found that lateral displacement of CW is a mechanism by which changes in the shape of the costal diaphragm, as described by its curvature, are limited.

scholarly journals Individual Sarcomere Lengths in Whole Muscle Fibers and Optimal Fiber Length Computation

2010 ◽  
Vol 293 (11) ◽  
pp. 1913-1919 ◽  
Author(s):  
Benjamin W. Infantolino ◽  
Michael J. Ellis ◽  
John H. Challis
Keyword(s):  
Fiber Length ◽  
Muscle Fibers ◽  
Whole Muscle
Sign in / Sign up

Export Citation Format

Share Document