Vitamins/Minerals: Invaluable Cellular Components for Optimal Physiological Function

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

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Ultrastructure of Choriocarcinoma in Vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006372x ◽

1969 ◽

Vol 27 ◽

pp. 362-363

Author(s):

John C. Garancis ◽

R. A. Pattillo

Keyword(s):

Cell Line ◽

Physiological Function ◽

Cell System ◽

Bewo Cell ◽

Bewo Cells ◽

Gestational Choriocarcinoma ◽

Bewo Cell Line

Growth of cell system (BeWo-cell line) derived from human gestational choriocarcinoma has been established and continuously maintained in-vitro. Furthermore, it is evident from the previous studies that this cell line has retained the physiological function of the placental trophoblasts, namely the synthesis of human chorionic gonadotrophil(HCG).The BeWo cells were relatively small and possessed single nuclei, thus indicating that this cell line consists exclusively of cytotrophoblasts. In some instances cells appeared widely separated and their lateral surfaces were provided with numerous microvilli (Fig.1).

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Mitochondrial Reconstructions Based on Serial Thick Sections and HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100115055 ◽

1975 ◽

Vol 33 ◽

pp. 286-287

Author(s):

Jerome J. Paulin

Keyword(s):

Imaging Techniques ◽

Three Dimensional ◽

Posterior Pole ◽

Dimensional Structure ◽

Stereo Imaging ◽

Thin Sections ◽

Anatomical Features ◽

The Past ◽

Cellular Components ◽

Mitochondrial Reticulum

Within the past decade it has become apparent that HVEM offers the biologist a means to explore the three-dimensional structure of cells and/or organelles. Stereo-imaging of thick sections (e.g. 0.25-10 μm) not only reveals anatomical features of cellular components, but also reduces errors of interpretation associated with overlap of structures seen in thick sections. Concomitant with stereo-imaging techniques conventional serial Sectioning methods developed with thin sections have been adopted to serial thick sections (≥ 0.25 μm). Three-dimensional reconstructions of the chondriome of several species of trypanosomatid flagellates have been made from tracings of mitochondrial profiles on cellulose acetate sheets. The sheets are flooded with acetone, gluing them together, and the model sawed from the composite and redrawn.The extensive mitochondrial reticulum can be seen in consecutive thick sections of (0.25 μm thick) Crithidia fasciculata (Figs. 1-2). Profiles of the mitochondrion are distinguishable from the anterior apex of the cell (small arrow, Fig. 1) to the posterior pole (small arrow, Fig. 2).

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Solving the mechanisms responsible for organelle behavior in vivo by same-cell correlative light and electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100120473 ◽

1992 ◽

Vol 50 (1) ◽

pp. 14-15

Author(s):

Conly L. Rieder

Keyword(s):

Electron Microscopy ◽

Quantitative Analysis ◽

Light Microscopy ◽

Living Cell ◽

Light And Electron Microscopy ◽

Time Behavior ◽

Dynamic Interactions ◽

Positive Identification ◽

Cellular Components

The behavior of many cellular components, and their dynamic interactions, can be characterized in the living cell with considerable spatial and temporal resolution by video-enhanced light microscopy (video-LM). Indeed, under the appropriate conditions video-LM can be used to determine the real-time behavior of organelles ≤ 25-nm in diameter (e.g., individual microtubules—see). However, when pushed to its limit the structures and components observed within the cell by video-LM cannot be resolved nor necessarily even identified, only detected. Positive identification and a quantitative analysis often requires the corresponding electron microcopy (EM).

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Discovery of intracellular 2,8 dihydroxyadenine crystals in bovine lymphatic and hepatic cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012881x ◽

1987 ◽

Vol 45 ◽

pp. 906-907

Author(s):

W. E. Rigsby ◽

D. M. Hinton ◽

V. J. Hurst ◽

P. C. McCaskey

Keyword(s):

Polarized Light ◽

Paraffin Sections ◽

Tissue Samples ◽

Whole Cells ◽

Tissue Sections ◽

Hepatic Cells ◽

Slaughter House ◽

Mammalian Tissues ◽

Carbon Coated ◽

Cellular Components

Crystalline intracellular inclusions are rarely seen in mammalian tissues and are often difficult to positively identify. Lymph node and liver tissue samples were obtained from two cows which had been rejected at the slaughter house due to the abnormal appearance of these organs in the animals. The samples were fixed in formaldehyde and some of the fixed material was embedded in paraffin. Examination of the paraffin sections with polarized light microscopy revealed the presence of numerous crystals in both hepatic and lymph tissue sections. Tissue sections were then deparaffinized in xylene, mounted, carbon coated, and examined in a Phillips 505T SEM equipped with a Tracor Northern X-ray Energy Dispersive Spectroscopy (EDS) system. Crystals were obscured by cellular components and membranes so that EDS spectra were only obtainable from whole cells. Tissue samples which had been fixed but not paraffin-embedded were dehydrated, embedded in Spurrs plastic, and sectioned.

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Methods for three-dimensional reconstruction of cellular components within a thick section

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141871 ◽

1986 ◽

Vol 44 ◽

pp. 18-21

Author(s):

J. Frank ◽

B. F. McEwen ◽

M. Radermacher ◽

C. L. Rieder

Keyword(s):

Tilt Angle ◽

Tomographic Reconstruction ◽

3D Structure ◽

Three Dimensional ◽

Thick Section ◽

Three Dimensional Reconstruction ◽

Axis Ratio ◽

Dimensional Reconstruction ◽

Cellular Components

The tomographic reconstruction from multiple projections of cellular components, within a thick section, offers a way of visualizing and quantifying their three-dimensional (3D) structure. However, asymmetric objects require as many views from the widest tilt range as possible; otherwise the reconstruction may be uninterpretable. Even if not for geometric obstructions, the increasing pathway of electrons, as the tilt angle is increased, poses the ultimate upper limitation to the projection range. With the maximum tilt angle being fixed, the only way to improve the faithfulness of the reconstruction is by changing the mode of the tilting from single-axis to conical; a point within the object projected with a tilt angle of 60° and a full 360° azimuthal range is then reconstructed as a slightly elliptic (axis ratio 1.2 : 1) sphere.

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A comparison of three cryotechniques (freeze-drying, cryosubstitution, cryosectioning) of specimen preparation for immunolabelling of bacterial antigens of Coxiella burnetii

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168438 ◽

1994 ◽

Vol 52 ◽

pp. 140-141

Author(s):

T. F. McCaul ◽

R. J. Gould

Keyword(s):

Coxiella Burnetii ◽

Freeze Drying ◽

Stress Proteins ◽

Cultured Cells ◽

High Specificity ◽

Specimen Preparation ◽

Bacterial Antigens ◽

Structural Preservation ◽

Nuclear Ribonucleoprotein ◽

Cellular Components

Immuno-electron microscopy has allowed the selective localisation of molecules with high resolution and high specificity. Cryopreparatory methods have provided better retention of antigenicity suitable for precise immunolabelling together with optimal structural preservation of cellular components. Cryosubstitution and cryoultramicrotomy have widely been exploited for immunolabelling. Molecular Distillation Dryer (MDD), a form of freeze-drying technique, has recently been used for immunolabelling of Plasmodium falciparum stress proteins and nuclear ribonucleoprotein particles in cultured cells. In the present study, we report the comparison of all three cryotechniques in the immunolabelling of bacterial antigens of Coxiella burnetii.The highly infectious C. burnetii was prefixed in 3% glutaraldehyde (66 mM cacodylate buffer, pH 6.8 ). The cells were then pre-embedded in 2% low-temperature agarose on Durapore hydrophilic membrane prior to cryofixation using a LifeCell CF100 metal-mirror system. A 1% glutaraldehyde in 100% methanol was used as a medium for cryosubstitution in a Reichert CS Auto Cryosubstitution apparatus.

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Label-free, mass-sensitive single-molecule imaging using interferometric scattering microscopy

Essays in Biochemistry ◽

10.1042/ebc20200023 ◽

2020 ◽

Author(s):

Nikolas Hundt

Keyword(s):

Single Molecule ◽

Cellular Systems ◽

Single Molecule Imaging ◽

Label Free ◽

Measurement Sensitivity ◽

Mass Distributions ◽

Quantitative Measurements ◽

Contrast Mechanism ◽

Cellular Components ◽

Scattering Signal

Abstract Single-molecule imaging has mostly been restricted to the use of fluorescence labelling as a contrast mechanism due to its superior ability to visualise molecules of interest on top of an overwhelming background of other molecules. Recently, interferometric scattering (iSCAT) microscopy has demonstrated the detection and imaging of single biomolecules based on light scattering without the need for fluorescent labels. Significant improvements in measurement sensitivity combined with a dependence of scattering signal on object size have led to the development of mass photometry, a technique that measures the mass of individual molecules and thereby determines mass distributions of biomolecule samples in solution. The experimental simplicity of mass photometry makes it a powerful tool to analyse biomolecular equilibria quantitatively with low sample consumption within minutes. When used for label-free imaging of reconstituted or cellular systems, the strict size-dependence of the iSCAT signal enables quantitative measurements of processes at size scales reaching from single-molecule observations during complex assembly up to mesoscopic dynamics of cellular components and extracellular protrusions. In this review, I would like to introduce the principles of this emerging imaging technology and discuss examples that show how mass-sensitive iSCAT can be used as a strong complement to other routine techniques in biochemistry.

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