scholarly journals Ultrastructural and physiological studies on the longitudinal body wall muscle of Dolabella auricularia. II. Localization of intracellular calcium and its translocation during mechanical activity.

1978 ◽  
Vol 79 (2) ◽  
pp. 467-478 ◽  
Author(s):  
S Suzuki ◽  
H Sugi
Keyword(s):  
Plasma Membrane ◽  
Electron Probe ◽  
Body Wall ◽  
Mechanical Response ◽  
Body Wall Muscle ◽  
Mechanical Activity ◽  
Relaxation Cycle ◽  
X Ray ◽  
Dolabella Auricularia ◽  
Inner Surface

The localization of Ca-accumulating structures in the longitudinal body wall muscle (LBWM) of the opisthobranch mollusc Dolabella auricularia and their role in the contraction-relaxation cycle were studied by fixing the LBWM fibers at rest and during mechanical response to 400 mM K or to 10(-4)--10(-3) M acetylcholine in a 1% OsO4 solution containing 2% K pyroantimonate. In the resting fibers, electron-opaque pyroantimonate precipitate was mostly localized at the peripheral structures, i.e., along the inner surface of the plasma membrane, at the membrane of the surface tubules, and at the sarcoplasmic reticulum. In the fibers fixed during mechanical activity, the precipitate was diffusely distributed in the myoplasm in the form of numerous particles with corresponding decrease in the amount of the precipitate at the peripheral structures. Electron-probe X-ray microanalysis showed the presence of Ca in the precipitate, indicating that the precipitate may serve as a measure of Ca localization. These results are in accord with the view that, in the LBWM, the Ca stored in the peripheral structures is released into the myoplasm to activate the contractile mechanism.

scholarly journals Ultrastructural and physiological studies on the longitudinal body wall muscle of Dolabella auricularia. I. Mechanical response and ultrastructure.

1978 ◽  
Vol 79 (2) ◽  
pp. 454-466 ◽  
Author(s):  
H Sugi ◽  
S Suzuki
Keyword(s):  
Body Wall ◽  
Mechanical Response ◽  
Body Movement ◽  
Smooth Muscles ◽  
Fiber Surface ◽  
Membrane Depolarization ◽  
Body Wall Muscle ◽  
Free Solution ◽  
Physiological Properties ◽  
Dolabella Auricularia

The physiological properties of mechanical response and the ultrastructure in the longitudinal body wall muscle (LBWM) of the opisthobranch mollusc Dolabella auricularia were studied to obtain information about excitation-contraction coupling in somatic smooth muscles responsible for smooth and slow body movement of molluscans. The contracture tension produced by 400 mM K was not affected by Mn ions (5--10 mM) and low pH (up to 4.0), but was reduced by procaine (2 mM). The K-contracture tension was not readily eliminated in a Ca-free solution containing ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetate (EGTA). A large contracture tension was also produced by rapid cooling of the surrounding fluid from 20 degrees to 5 degrees--3 degrees C even when the preparation showed no mechanical response to 400 mM K after prolonged (more than 2 h) soaking in the Ca-free solution. These results indicate that the LBWM fibers contain a large amount of intracellularly stored Ca which can be effectively released by membrane depolarization. The fibers were connected with each other, forming the gap junctions, the desmosomes, and the intermediate junctions. The sarcoplasmic reticulum (SR) consisted of vesicular and tubular elements, and was mostly located near the fiber surface. The plasma membrane showed marked tubular invaginations of 600-800 A in diameter, with many branches (surface tubules), extending inwards for approximately 2 micron. These surface tubules were closely apposed to the SR, and the bridgelike structures analogous to those in the triadic junction of vertebrate skeletal muscle were observed in the space between the surface tubules and the SR. It is suggested that the influence of membrane depolarization is transmitted inwards along the surface tubules to cause the release of Ca from the SR.

Physiological and ultrastructural studies on the longitudinal retractor muscle of a sea cucumber Stichopus japonicus. II. Intracellular localization and translocation of activator calcium during mechanical activity

1982 ◽  
Vol 97 (1) ◽  
pp. 113-119
Author(s):  
S. Suzuki ◽  
H. Sugi
Keyword(s):  
Plasma Membrane ◽  
Sea Cucumber ◽  
Mechanical Response ◽  
Intracellular Localization ◽  
Mechanical Activity ◽  
Retractor Muscle ◽  
Stichopus Japonicus ◽  
X Ray ◽  
Ultrastructural Studies ◽  
High K

1. The intracellular localization and translocation of activator Ca in the longitudinal retractor muscle (LRM) of a sea cucumber Stichopus japonicus were studied by fixing the LRM in a 1% OsO4 solution containing 2% K pyroantimonate. 2. In the resting LRM fibres, electron-opaque pyroantimonate precipitate was mostly localized along the inner surface of the plasma membrane and at the subsarcolemmal vesicles in close apposition to the plasma membrane. 3. In the LRM fibres fixed during the mechanical response to ACh and high [K]0, the precipitate was diffusely distributed in the myoplasm in the form of numerous particles with corresponding decrease in the amount of the precipitate at the peripheral structures. 4. Electron probe X-ray microanalysis showed the presence of Ca in the precipitate, indicating that the precipitate provides a valid measure of Ca localization. 5. These results accord with the view that, in the LRM, the contractile mechanism is activated by the release of Ca from the intracellular structures as well as by the inward movement of extracellular Ca.

Electron-probe x-ray microanalysis studies on the intracellular calcium translocation during the contraction-relaxation cycle in the fish swimbladder muscle

1990 ◽  
Vol 48 (2) ◽  
pp. 168-169
Author(s):  
Suechika Suzuki ◽  
Naoki Hino ◽  
Haruo Sugi
Keyword(s):  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Teleost Fish ◽  
Electron Probe ◽  
Middle Portion ◽  
Relaxation Cycle ◽  
X Ray ◽  
Thin Carbon ◽  
Freeze Dried ◽  
Intracellular Ca

The swimbladder muscle of a teleost fish, Sebasticus marmoratus, contracts rapidly to produce sounds for communication and contains extremely well developed sarcoplasmic reticulum (SR), providing a material suitable for studying the intracellular Ca translocation during the contraction-relaxation cycle. We examined the change of Ca distribution along the sarcomere at various states of the fibers during the contractionrelaxation cycle in the swimbladder muscle by means of quantitative electron probe X-ray microanalysis of cryosections.The muscle fibers were rapidly frozen at rest, during sustained contraction and at 0.1 and 1.0 sec after the onset of relaxation with a dual-jet liquid propane freezing device. Cryosections (200 nm thick) were cut from the middle portion of the frozen fibers at -110°C on a LKB NOVA cryoultramicrotome, and placed on thin carbon supporting films on Nigrids. Then the cryosections were freeze-dried at 10-6 torr and below -80°C. Electron probe X-ray microanalysis was performed on a liquid N2-cooled Be-stage at -130°C in a JEOL 2000FX electron microscope operated at 80 kV and equipped with a Tracor Northern TN5500 energy dispersive X-ray microanalyzer.

Improvements in the electron probe forming capabilities and x-ray hole counts in the Philips TEM

1983 ◽  
Vol 41 ◽  
pp. 376-377
Author(s):  
Richard L. McConville
Keyword(s):  
Field Strength ◽  
Electron Probe ◽  
Spherical Aberration ◽  
Focal Length ◽  
Objective Lens ◽  
Parallel Beam ◽  
Tilt Axis ◽  
X Ray ◽  
Small Probe ◽  
Specimen Height

A second generation twin lens has been developed. This symmetrical lens with a wider bore, yet superior values of chromatic and spherical aberration for a given focal length, retains both eucentric ± 60° tilt movement and 20°x ray detector take-off angle at 90° to the tilt axis. Adjust able tilt axis height, as well as specimen height, now ensures almost invariant objective lens strengths for both TEM (parallel beam conditions) and STEM or nano probe (focused small probe) modes.These modes are selected through use of an auxiliary lens situ ated above the objective. When this lens is on the specimen is illuminated with a parallel beam of electrons, and when it is off the specimen is illuminated with a focused probe of dimensions governed by the excitation of the condenser 1 lens. Thus TEM/STEM operation is controlled by a lens which is independent of the objective lens field strength.

Spatial resolution of X-ray microanalysis in thin foils

1978 ◽  
Vol 36 (1) ◽  
pp. 544-545
Author(s):  
R. Hutchings ◽  
I.P. Jones ◽  
M.H. Loretto ◽  
R.E. Smallman
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
Beam Divergence ◽  
Inelastic Interaction ◽  
Specimen Thickness ◽  
High Current ◽  
Beam Spreading ◽  
X Ray ◽  
Thin Foils ◽  
Complex Calculation

There is increasing interest in X-ray microanalysis of thin specimens and the present paper attempts to define some of the factors which govern the spatial resolution of this type of microanalysis. One of these factors is the spreading of the electron probe as it is transmitted through the specimen. There will always be some beam-spreading with small electron probes, because of the inevitable beam divergence associated with small, high current probes; a lower limit to the spatial resolution is thus 2αst where 2αs is the beam divergence and t the specimen thickness.In addition there will of course be beam spreading caused by elastic and inelastic interaction between the electron beam and the specimen. The angle through which electrons are scattered by the various scattering processes can vary from zero to 180° and it is clearly a very complex calculation to determine the effective size of the beam as it propagates through the specimen.

High spatial resolution x-ray microanalysis of interfaces

1995 ◽  
Vol 53 ◽  
pp. 284-285
Author(s):  
J. R. Michael
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
Solid Angle ◽  
Collection Efficiency ◽  
Spatial Scales ◽  
Energy Dispersive Spectrometer ◽  
X Rays ◽  
X Ray ◽  
Probe Size ◽  
Brightness Field

X-ray microanalysis in the analytical electron microscope (AEM) refers to a technique by which chemical composition can be determined on spatial scales of less than 10 nm. There are many factors that influence the quality of x-ray microanalysis. The minimum probe size with sufficient current for microanalysis that can be generated determines the ultimate spatial resolution of each individual microanalysis. However, it is also necessary to collect efficiently the x-rays generated. Modern high brightness field emission gun equipped AEMs can now generate probes that are less than 1 nm in diameter with high probe currents. Improving the x-ray collection solid angle of the solid state energy dispersive spectrometer (EDS) results in more efficient collection of x-ray generated by the interaction of the electron probe with the specimen, thus reducing the minimum detectability limit. The combination of decreased interaction volume due to smaller electron probe size and the increased collection efficiency due to larger solid angle of x-ray collection should enhance our ability to study interfacial segregation.

Microchemical imaging in biomedical research

1992 ◽  
Vol 50 (2) ◽  
pp. 1118-1119
Author(s):  
P. Ingram
Keyword(s):  
Data Analysis ◽  
Electron Probe ◽  
The Other ◽  
X Ray ◽  
Cell Element ◽  
Physiological Information ◽  
Functional States ◽  
Elemental Maps ◽  
Electron Energy Loss ◽  
Secondary Ion

It is well established that unique physiological information can be obtained by rapidly freezing cells in various functional states and analyzing the cell element content and distribution by electron probe x-ray microanalysis. (The other techniques of microanalysis that are amenable to imaging, such as electron energy loss spectroscopy, secondary ion mass spectroscopy, particle induced x-ray emission etc., are not addressed in this tutorial.) However, the usual processes of data acquisition are labor intensive and lengthy, requiring that x-ray counts be collected from individually selected regions of each cell in question and that data analysis be performed subsequent to data collection. A judicious combination of quantitative elemental maps and static raster probes adds not only an additional overall perception of what is occurring during a particular biological manipulation or event, but substantially increases data productivity. Recent advances in microcomputer instrumentation and software have made readily feasible the acquisition and processing of digital quantitative x-ray maps of one to several cells.

Reduction of Potassium in Kidney Proximal Tubules to Aid in Electron Probe X-Ray Microanalysis of Calcium

1985 ◽  
Vol 43 ◽  
pp. 474-475
Author(s):  
A. LeFurgey ◽  
P. Ingram ◽  
L.J. Mandel
Keyword(s):  
Smooth Muscle ◽  
Proximal Tubule ◽  
Electron Probe ◽  
Clinical Applications ◽  
Proximal Tubules ◽  
Rabbit Kidney ◽  
Target Cells ◽  
X Ray ◽  
Freeze Dried

For quantitative determination of subcellular Ca distribution by electron probe x-ray microanalysis, decreasing (and/or eliminating) the K content of the cell maximizes the ability to accurately separate the overlapping K Kß and Ca Kα peaks in the x-ray spectra. For example, rubidium has been effectively substituted for potassium in smooth muscle cells, thus giving an improvement in calcium measurements. Ouabain, a cardiac glycoside widely used in experimental and clinical applications, inhibits Na-K ATPase at the cell membrane and thus alters the cytoplasmic ion (Na,K) content of target cells. In epithelial cells primarily involved in active transport, such as the proximal tubule of the rabbit kidney, ouabain rapidly (t1/2= 2 mins) causes a decrease2 in intracellular K, but does not change intracellular total or free Ca for up to 30 mins. In the present study we have taken advantage of this effect of ouabain to determine the mitochondrial and cytoplasmic Ca content in freeze-dried cryosections of kidney proximal tubule by electron probe x-ray microanalysis.

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