Observations on the origin of Chloroplasts and Mitochondria in the leaf cells of higher plants

1965 ◽  
Vol 13 (2) ◽  
pp. 161 ◽  
Author(s):  
M Vesk ◽  
FV Mercer ◽  
JV Possingham
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Light Microscope ◽  
Higher Plants ◽  
Mature Leaf ◽  
Mesophyll Cells

The chloroplasts and mitochondria in embryonic and mature mesophyll cells of maize, spinach, and barley were studied by electron microscopy. The observations are discussed in relation to theories of organelle status and origins. Some of the e!ectron micrographs can be interpreted as showing that mitochondria arise from chloroplasts in mature leaf cells, and lend support to the view, based on cinephotomicrographic studies, that interconversions between chloroplasts and mitochondria like bodies occur in living mature leaf cells. In contrast, other electron micrographs can be interpreted as showing that mitochondria do not arise from chloroplasts, and that the cinephotographic observations refer to pre-existing mitochondria that have been enclosed previously by the deformable chloroplast. Electron micrographs of developing cells, in which the number of organelles increases, do not support the possibility of interconversions of organelles in young cells. To the contrary, the data for the young cells suggest that both organelles undergo divisions, supporting the view that the organelles are autonomous bodies. Some of the difficulties of correlating and interpreting electron microscope and light microscope observations of the same events are stressed.

scholarly journals ELECTRON MICROSCOPE STUDIES ON THE DICTYOSOMES AND ACROBLASTS IN THE MALE GERM CELLS OF THE CRICKET

1956 ◽  
Vol 2 (4) ◽  
pp. 123-128 ◽  
Author(s):  
H. W. Beams ◽  
T. N. Tahmisian ◽  
R. L. Devine ◽  
Everett Anderson
Keyword(s):  
Electron Microscope ◽  
Golgi Apparatus ◽  
Electron Micrographs ◽  
Germ Cells ◽  
Light Microscope ◽  
Golgi Body ◽  
Duplex Structure ◽  
Male Germ Cells ◽  
Secondary Spermatocyte ◽  
A Chain

The dictyosome (Golgi body) in the secondary spermatocyte of the cricket appears in electron micrographs as a duplex structure composed of (a) a group of parallel double-membraned lamellae and (b) a group of associated vacuoles arranged along the compact lamellae in a chain-like fashion. This arrangement of ultramicroscopic structure for the dictyosomes is strikingly comparable to that described for the Golgi apparatus of vertebrates. Accordingly, the two are considered homologous structures. Associated with the duplex structure of the dictyosomes is a differentiated region composed of small vacuoles. This is thought to represent the pro-acrosome region described in light microscope preparations. In the spermatid the dictyosomes fuse, giving rise to the acroblast. Like the dictyosomes, the acroblasts are made up of double-membraned lamellae and associated vacuoles. In addition, a differentiated acrosome region is present which, in some preparations, may display the acrosome vacuole and granule. Both the dictyosomes and acroblasts are distinct from mitochondria.

The Ultra-fine Structure of Lipid Globules in the Neurones of Helix aspersa

1958 ◽  
Vol s3-99 (46) ◽  
pp. 279-284
Author(s):  
J.T. Y. CHOU ◽  
G. A. MEEK
Keyword(s):  
Methylene Blue ◽  
Fine Structure ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Light Microscope ◽  
Helix Aspersa

The three kinds of lipid globules recognizable in the living neurones of Helix aspersa have been examined under the electron microscope. The globules of the kind that can be stained blue with methylene blue during life are seen in electron micrographs as spheres or spheroids, with concentric lamination, after calcium-osmium fixation. After fixation with sucrose-osmium laminated crescentic bodies are seen instead; these appear to be formed by distortion of the ‘blue’ globules. The yellow globules contain electrondense material, and sometimes appear reticular. It is possible that the yellow globules may originate by transformation of some of the ‘blue’ globules. The colourless globules generally appear as crenated objects; this appearance may be a shrinkage artifact. Apart from the mitochondria and the three kinds of lipid globules described, no other object large enough to be identified with the light microscope has been seen in the cytoplasm.

scholarly journals AN ELECTRON MICROSCOPE STUDY OF THE EMBRYOLOGY OF THE INTERCALATED DISC IN THE HEART OF THE RABBIT

1957 ◽  
Vol 3 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Alan R. Muir
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Cardiac Muscle ◽  
Microscope Study ◽  
Light Microscope ◽  
Electron Microscope Study ◽  
Muscle Cells ◽  
Intercalated Disc ◽  
Adult Cell ◽  
Embryonic Muscle

Prenatal and postnatal cardiac muscle from rabbits has been studied by electron microscopy, after osmium fixation and methacrylate embedding. The observations showed that 1. Cell membranes divide the muscle into cellular units from the youngest embryo which was studied (9½ days after coitus) until the adult state. 2. The embryonic muscle cells contain only one nucleus, whereas the adult cell may be multinucleated. 3. At all stages of development, wherever a myofibrillar axis crosses a cellular boundary, the myofilaments are interrupted by an intercalated disc. 4. With age, increase in size and complexity of the discs render them recognisable by the light microscope.

scholarly journals Individual microtubules viewed by immunofluorescence and electron microscopy in the same PtK2 cell

1978 ◽  
Vol 77 (3) ◽  
pp. R27 ◽  
Author(s):  
M Osborn ◽  
RE Webster ◽  
K Weber
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscope ◽  
Immunofluorescence Microscopy ◽  
Uranyl Acetate ◽  
Tubulin Antibodies ◽  
Ptk2 Cell ◽  
Cytoplasmic Microtubules ◽  
Triton X ◽  
Microtubular Structures

PtK2 cells were grown on gold grids and treated with Triton X-100 in a microtubule stabilizing buffer. The resulting cytoskeletons were fixed with glutaraldehyde and subjected to the indirect immunofluorescence procedure using monospecific tubulin antibodies. Grids were examined first by fluorescence microscopy, and the display of fluorescent cytoplasmic microtubules was recorded. The grids were then stained with uranyl acetate and the display of fibrous structures recorded by electron microscopy. Thus the display of cytoplasmic microtubular structures in the light microscope and the electron microscope can be compared within the same cytoskeleton. The results show a direct correspondence of the fluorescent fibers in the light microscope with uninterrupted fibers of diameter approximately 550 A in the electron microscope. This is the diameter reported for a single microtubule decorated around its circumference by two layers of antibody molecules. Thus under optimal conditions immunofluorescence microscopy can visualize individual microtubules.

scholarly journals Scanning Electron Microscopy Observations of Loa loa (Nematoda)

2020 ◽  
Vol 11 (2) ◽  
pp. 486-492
Author(s):  
Jens Anibal Juul ◽  
Vegard Asgeir Forsaa ◽  
Tor Paaske Utheim ◽  
Endre Willassen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Case Report ◽  
Scanning Electron Microscope ◽  
Light Microscope ◽  
Loa Loa ◽  
Scanning Electron

We present a case report of periocular Loa loa. The key feature of L. loa distinguishing it from other human filarial parasites are cuticular bosses, which are presented in images from a light microscope and a scanning electron microscope. The cuticular bosses could be divided into three subtypes not previously described.

Bridging the Resolution Gap: Correlated 3D Light and Electron Microscopic Analysis of Large Biological Structures

1999 ◽  
Vol 5 (S2) ◽  
pp. 526-527
Author(s):  
Maryann E. Martone
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Surface Area ◽  
Light Microscope ◽  
Microscopic Analysis ◽  
Electron Microscopic Analysis ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Biological Structures ◽  
Ganglion Neurons

One class of biological structures that has always presented special difficulties to scientists interested in quantitative analysis is comprised of extended structures that possess fine structural features. Examples of these structures include neuronal spiny dendrites and organelles such as the Golgi apparatus and endoplasmic reticulum. Such structures may extend 10's or even 100's of microns, a size range best visualized with the light microscope, yet possess fine structural detail on the order of nanometers that require the electron microscope to resolve. Quantitative information, such as surface area, volume and the micro-distribution of cellular constituents, is often required for the development of accurate structural models of cells and organelle systems and for assessing and characterizing changes due to experimental manipulation. Performing estimates of such quantities from light microscopic data can result in gross inaccuracies because the contribution to total morphometries of delicate features such as membrane undulations and excrescences can be quite significant. For example, in a recent study by Shoop et al, electron microscopic analysis of cultured chick ciliary ganglion neurons showed that spiny projections from the plasmalemma that were not well resolved in the light microscope effectively doubled the surface area of these neurons.While the resolution provided by the electron microscope has yet to be matched or replaced by light microscopic methods, one drawback of electron microscopic analysis has always been the relatively small sample size and limited 3D information that can be obtained from samples prepared for conventional transmission electron microscopy. Reconstruction from serial electron micrographs has provided one way to circumvent this latter problem, but remains one of the most technically demanding skills in electron microscopy. Another approach to 3D electron microscopic imaging is high voltage electron microscopy (HVEM). The greater accelerating voltages of HVEM's allows for the use of much thicker specimens than conventional transmission electron microscopes.

Nucleation in silver azide: an investigation by electron microscopy and diffraction

1955 ◽  
Vol 229 (1176) ◽  
pp. 135-142 ◽  
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Single Crystals ◽  
Electron Micrographs ◽  
The Other ◽  
Metallic Silver ◽  
Silver Azide ◽  
Cubic Lattice ◽  
Early Stages ◽  
Last Stage

The beam of an electron microscope has been used to decompose single crystals of silver azide into nitrogen and metallic silver. The decomposition was slow enough to allow electrondiffraction photographs and electron micrographs to be taken at various stages of the decomposition. From these observations it is possible to follow very closely the process of nucleation. The diffraction photographs show that two forms of silver result, one highly oriented and the other randomly oriented. The microscope identifies the two forms. The randomly oriented silver appears to separate at the boundaries of a substructure of the crystal. The highly oriented silver exists as discrete nuclei, of dimensions of the order 0.1 x 0.1 x 0.05p, probably formed near the surface of the silver azide crystal. The nuclei consist of normal metallic silver only at the end of the decomposition. There is no evidence for the formation in the early stages of a small speck of metallic silver which then grows. Rather, a nucleus is a region into which silver diffuses to build up a face-centred cubic lattice of parameter greater than that of normal silver, and which uses the silver positions in the silver azide lattice as the basis for this build-up. In the last stage a collapse to normal metallic silver takes place. During decomposition the size of a nucleus does not appear to change, but the density increases.

Mucilaginous film production by plant cells immobilised in a polyurethane or nylon matrix

1985 ◽  
Vol 63 (12) ◽  
pp. 2357-2363 ◽  
Author(s):  
M. J. C. Rhodes ◽  
R. J. Robins ◽  
R. J. Turner ◽  
J. I. Smith
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscope ◽  
Plant Cells ◽  
The Matrix ◽  
Nylon Fibre ◽  
Scanning Electron

The surface features of plant cells immobilised in a matrix of either reticulated polyurethane foam or nylon fibre have been examined with the scanning electron microscope. It has been found that both cells and matrix are enveloped in a thin film, the appearance of which is very dependent on the method by which material is prepared for scanning electron microscopy. The structure is severely damaged by fixation and dehydration. Only in specimens examined in the frozen hydrated state is a structure seen compatible with that observed with the light microscope. From the way the appearance of the film is affected by different methods of preparation for the scanning electron microscope, it is suggested that the film is a hydrated mucilage. The importance of this film for the retention of cells within the matrix is discussed.

scholarly journals ELECTRON MICROSCOPY OF THE AMMONIACAL SILVER REACTION FOR HISTONES IN THE ERYTHROPOIETIC CELLS OF THE CHICK

1970 ◽  
Vol 45 (2) ◽  
pp. 235-245 ◽  
Author(s):  
Edith K. MacRae ◽  
Gerald D. Meetz
Keyword(s):  
Electron Microscopy ◽  
Stem Cells ◽  
Bone Marrow ◽  
Electron Microscope ◽  
Light Microscope ◽  
Color Difference ◽  
Erythroid Cell ◽  
Erythroid Cells ◽  
Cell Series ◽  
Ammoniacal Silver

The product of the postformalin ammoniacal silver reaction, which has been claimed to distinguish lysine-rich from arginine-rich histones with the light microscope on the basis of a color difference, was examined in developing erythroid cells of chick bone marrow with the electron microscope. Stem cells and early erythroblasts exhibit no, or little, ammoniacal silver reaction product, while small basophilic erythroblasts, polychromatophilic erythrocytes, and reticulocytes exhibit an increasing amount of reaction product as maturation proceeds. The reaction product is in the form of discrete electron-opaque particles associated with heterochromatin. The ammoniacal silver reaction in the erythroid cell series is interpreted as reflecting either the accumulation of newly synthesized arginine-rich histones or changes in the availability of reactive sites in preformed histones.

scholarly journals An Effective Method of Preparing Sections of Bacillus polymyxa Sporangia and Spores for Electron Microscopy

1960 ◽  
Vol 7 (2) ◽  
pp. 373-376 ◽  
Author(s):  
Pauline E. Holbert
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Epoxy Resins ◽  
Bacillus Polymyxa ◽  
Thin Sections ◽  
Similar Images ◽  
Embedding Medium ◽  
First Time ◽  
Diamond Knife

Bacillus polymyxa sporangia and spores were prepared for examination in the electron microscope by methods whose critical features were apparently: judicious use of vacuum, to encourage complete penetration of the embedding medium; the use of epoxy resins as embedding media; and cutting of the thin sections with a diamond knife. Electron micrographs of material prepared in this manner exhibit undeformed sporangial sections. Some of the structures revealed have been shown before, though perhaps less distinctly; other structures are revealed here for the first time. While this single study does not pretend to elucidate all the complexities of sporulation in bacteria, these and similar images should make this possible, and some mention of the preparatory techniques that lead to them seems advisable at this time.

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