Faculty Opinions recommendation of Composition of vacuoles and sarcoplasmic reticulum in fatigued muscle: electron probe analysis.

2016 ◽  
Author(s):  
Bradley Launikonis
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Electron Probe ◽  
Electron Probe Analysis ◽  
Probe Analysis ◽  
Fatigued Muscle

scholarly journals Composition of vacuoles and sarcoplasmic reticulum in fatigued muscle: electron probe analysis.

1978 ◽  
Vol 75 (3) ◽  
pp. 1329-1333 ◽  
Author(s):  
H. Gonzalez-Serratos ◽  
A. V. Somlyo ◽  
G. McClellan ◽  
H. Shuman ◽  
L. M. Borrero ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Electron Probe ◽  
Electron Probe Analysis ◽  
Probe Analysis ◽  
Fatigued Muscle

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

ELECTRON PROBE ANALYSIS OF THE SARCOPLASMIC RETICULUM AND VACUOLATED T-TUBULE SYSTEM OF FATIGUED FROG MUSCLES

1978 ◽  
Vol 307 (1 Calcium Trans) ◽  
pp. 232-234 ◽  
Author(s):  
Avril V. Somlyo ◽  
H. Gonzalez-Serratos ◽  
G. McClellan ◽  
H. Shuman ◽  
L. M. Borrero ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Electron Probe ◽  
Electron Probe Analysis ◽  
Probe Analysis

scholarly journals ELECTRON MICROSCOPY AND ELECTRON PROBE ANALYSIS OF MITOCHONDRIAL CATION ACCUMULATION IN SMOOTH MUSCLE

1974 ◽  
Vol 61 (3) ◽  
pp. 723-742 ◽  
Author(s):  
A. P. Somlyo ◽  
A. V. Somlyo ◽  
C. E. Devine ◽  
P. D. Peters ◽  
T. A. Hall
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Vascular Smooth Muscle ◽  
Electron Probe ◽  
Average Distance ◽  
Main Pulmonary Artery ◽  
Mitochondrial Swelling ◽  
Electron Probe Analysis ◽  
X Ray ◽  
Probe Analysis

The contractile responses to barium and the ultrastructure and ionic composition of mitochondria were studied in vascular smooth muscle. In normal rabbit portal anterior mesenteric vein (PAMV) and main pulmonary artery (MPA) smooth muscle mitochondria were frequently associated with the surface vesicles. The average distance between the outer mitochondrial and inner surface vesicle membrane was 4–5 nm. Ba contractures of MPA were tonic and of PAMV were phasic. Incubation of MPA and PAMV with Ba resulted in the accumulation of mitochondrial granules, followed in the MPA by massive mitochondrial swelling. Oligomycin and anoxia inhibited the appearance of mitochondrial electron-opaque granules and prevented the Ba-induced mitochondrial swelling in the MPA. Electron probe analysis of mitochondria in PAMV incubated with Ba and containing granules showed characteristic Ba signals over the mitochondria. Electron probe X-ray microanalysis also showed a highly significant (P < 0.001) correlation of P with mitochondrial Ba, in an estimated elemental ratio of approximately 3 Ba/4 P. Mitochondrial granules were still prominent after block staining of the osmium-fixed, Ba-loaded PAMV, but electron probe microanalysis showed no Ba, but only U, emissions. Tissues incubated with strontium had electron-opaque mitochondrial granules and deposits in the sarcoplasmic reticulum. X-ray microanalysis of mitochondria containing granules showed the presence of characteristic Sr and Ca emissions. The presence of Sr was similarly verified in the sarcoplasmic reticulum. These findings indicate the energy dependent uptake of divalent cations, in association with phosphate, by mitochondria in vascular smooth muscle in situ and the possibility that mitochondria may contribute to the regulation of intracellular divalent cation levels in smooth muscle.

scholarly journals Calcium release and ionic changes in the sarcoplasmic reticulum of tetanized muscle: an electron-probe study.

1981 ◽  
Vol 90 (3) ◽  
pp. 577-594 ◽  
Author(s):  
A V Somlyo ◽  
H G Gonzalez-Serratos ◽  
H Shuman ◽  
G McClellan ◽  
A P Somlyo
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Binding ◽  
Electron Probe ◽  
Water Distribution ◽  
Calcium Release ◽  
Calcium Content ◽  
Frog Muscle ◽  
Chloride Permeability ◽  
Electron Probe Analysis ◽  
Probe Analysis

Approximately 60-70% of the total fiber calcium was localized in the terminal cisternae (TC) in resting frog muscle as determined by electron-probe analysis of ultrathin cryosections. During a 1.2 s tetanus, 59% (69 mmol/kg dry TC) of the calcium content of the TC was released, enough to raise total cytoplasmic calcium concentration by approximately 1 mM. This is equivalent to the concentration of binding sites on the calcium-binding proteins (troponin and parvalbumin) in frog muscle. Calcium release was associated with a significant uptake of magnesium and potassium into the TC, but the amount of calcium released exceeded the total measured cation accumulation by 62 mEq/kg dry weight. It is suggested that most of the charge deficit is apparent, and charge compensation is achieved by movement of protons into the sarcoplasmic reticulum (SR) and/or by the movement of organic co- or counterions not measured by energy dispersive electron-probe analysis. There was no significant change in the sodium or chlorine content of the TC during tetanus. The unchanged distribution of a permeant anion, chloride, argues against the existence of a large and sustained transSR potential during tetanus, if the chloride permeability of the in situ SR is as high as suggested by measurements on fractionated SR. The calcium content of the longitudinal SR (LSR) during tetanus did not show the LSR to be a major site of calcium storage and delayed return to the TC. The potassium concentration in the LSR was not significantly different from the adjacent cytoplasmic concentration. Analysis of small areas of I-band and large areas, including several sarcomeres, suggested that chloride is anisotropically distributed, with some of it probably bound to myosin. In contrast, the distribution of potassium in the fiber cytoplasm followed the water distribution. The mitochondrial concentration of calcium was low and did not change significantly during a tetanus. The TC of both tetanized and resting freeze-substituted muscles contained electron-lucent circular areas. The appearance of the TC showed no evidence of major volume changes during tetanus, in agreement with the estimates of unchanged (approximately 72%) water content of the TC obtained with electron-probe analysis.

scholarly journals Primary role of sarcoplasmic reticulum in phasic contractile activation of cardiac myocytes with shunted myolemma.

1981 ◽  
Vol 91 (3) ◽  
pp. 728-742 ◽  
Author(s):  
M Chiesi ◽  
M M Ho ◽  
G Inesi ◽  
A V Somlyo ◽  
A P Somlyo
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Electron Probe ◽  
Calcium Release ◽  
Contractile Activity ◽  
Heart Cells ◽  
Primary Role ◽  
Electron Probe Analysis ◽  
Ca Transport ◽  
Probe Analysis ◽  
Contractile Activation

Homogeneous populations of single myocytes showing good preservation of ultrastructure were obtained by enzymatic digestion of rabbit and rat hearts, and maintained in a relaxed state in the presence of free Ca2+ concentrations less than 10(-7) M. Ultrastructural details such as a cytoskeleton of 100-A filaments connected to the sarcolemma at the Z lines were demonstrated especially well in these preparations. In spite of seemingly normal structure, electron probe analysis of cryosections reveals similar concentrations of electrolytes in the medium and in the cytoplasm, indicating the presence of electrochemical shunting across the external membrane. The dissociated myocytes display Ca uptake and phasic contractions that are apparently dependent on mitochondrial respiration, but are not affected by mitochondrial uncouplers when ATP and phosphocreatine are added. The uptake is augmented by oxalate and, based on identification of calcium oxalate crystals by electron microscopy and electron probe analysis, is localized to the sarcoplasmic reticulum (SR). An advantageous feature of the dissociated myocytes is that they are suitable for experiments using large numbers of cells in suspension. Thereby, velocities of calcium transport were measured directly by isotopic tracer and filtration methods. It was then found that the lowest CA2+ concentrations (5 x 10(-7) M for the rabbit and 1 x 10(-7) M for the rat) sustaining Ca transport also induce phasic contractile activity in all myocytes, even though the external membrane is electrochemically shunted. A stepwise rise in the Ca2+ concentration of up to one order of magnitude, increases transport velocities in parallel with the rates of phasic contractions. Both these parameters are affected by Mg2+, temperature, cyclic-AMP, and methylxanthines, even though the Ca2+ concentration is maintained constant in the medium. Therefore, Ca transport by SR is a requirement and a rate limiting factor for the occurrence of phasic contractile activation in dissociated cardiac cells retaining an electrochemically shunted external membrane. It is suggested that transient Ca release required for phasic contractile activation is due to equilibrium oscillations across the SR membrane. The sequential pattern of sarcomere activation is consistent with a self propagating mechanism of calcium release. SR in dissociated skeletal muscle cells sustains a greater Ca transport activity than in dissociated heart cells. However, the heart cells display a much higher phasic contractile activity, indicating that cardiac SR has a greater tendency to release accumulated calcium. If free Ca2+ in the medium is raised above 10(-6) M, both cardiac and skeletal myocytes undergo contractures and degenerative phenomena, accompanied by Ca, Mg, and phosphate accumulation in cardiac mitochondria.

The use of a Bent Grid to Improve the take-Off Angle for Electron Probe Analysis

1976 ◽  
Vol 34 ◽  
pp. 360-361
Author(s):  
Delbert E. Philpott ◽  
David Leaffer
Keyword(s):  
Quantitative Analysis ◽  
Tilt Angle ◽  
Count Rate ◽  
Electron Probe ◽  
Open Area ◽  
Electron Probe Analysis ◽  
Background Ratio ◽  
Probe Analysis

There are certain advantages for electron probe analysis if the sample can be tilted directly towards the detector. The count rate is higher, it optimizes the geometry since only one angle need be taken into account for quantitative analysis and the signal to background ratio is improved. The need for less tilt angle may be an advantage because the grid bars are not moved quite as close to each other, leaving a little more open area for observation. Our present detector (EDAX) and microscope (Philips 300) combination precludes moving the detector behind the microscope where it would point directly at the grid. Therefore, the angle of the specimen was changed in order to optimize the geometry between the specimen and the detector.

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