Changes in Fine Structure of the Potato Meristem Following Heat Treatment for Virus Eradication

1976 ◽  
Vol 24 (5) ◽  
pp. 597 ◽  
Author(s):  
RJ Sward ◽  
ND Hallam
Keyword(s):  
Heat Treatment ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Solanum Tuberosum ◽  
Membrane Systems ◽  
Nutrient Media ◽  
Virus Eradication ◽  
Potato Virus S ◽  
Viral Spread ◽  
Heat Therapy

Potato virus S has been successfully eliminated from the 'Exton' cultivar of the potato (Solanum tuberosum 'Exton'). This has been achieved by a variety of heat treatments and variations in nutrient media for growing meristem tips. As part of this research program we have examined the fine structure of the meristem tips following heat therapy, and aberrant changes were seen in rough endoplasmic reticulum, ribosomes, mitochondria, chloroplasts and membrane systems. A combination of these changes retard viral spread and development within the meristem.

scholarly journals FINE STRUCTURE AND ORGANELLE ASSOCIATIONS IN BROWN ALGAE

1965 ◽  
Vol 26 (2) ◽  
pp. 523-537 ◽  
Author(s):  
G. Benjamin Bouck
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Nuclear Envelope ◽  
Brown Algae ◽  
Algal Cell ◽  
Plant Cells ◽  
Membrane Systems ◽  
Two Envelopes

The structural interrelationships among several membrane systems in the cells of brown algae have been examined by electron microscopy. In the brown algae the chloroplasts are surrounded by two envelopes, the outer of which in some cases is continuous with the nuclear envelope. The pyrenoid, when present, protrudes from the chloroplast, is also surrounded by the two chloroplast envelopes, and, in addition, is capped by a third dilated envelope or "pyrenoid sac." The regular apposition of the membranes around the pyrenoid contrasts with their looser appearance over the remainder of the chloroplast. The Golgi apparatus is closely associated with the nuclear envelope in all brown algae examined, but in the Fucales this association may extend to portions of the cytoplasmic endoplasmic reticulum as well. Evidence is presented for the derivation of vesicles, characteristic of those found in the formative region of the Golgi apparatus, from portions of the underlying nuclear envelope. The possibility that a structural channeling system for carbohydrate reserves and secretory precursors may be present in brown algae is considered. Other features of the brown algal cell, such as crystal-containing bodies, the variety of darkly staining vacuoles, centrioles, and mitochondria, are examined briefly, and compared with similar structures in other plant cells.

Study of fine structure of cold-deformed steel 20 before and after prerecrystallization heat treatment

2015 ◽  
Vol 0 (1) ◽  
Author(s):  
Oleksandr M. Dubovyi ◽  
Oleksandr V. Chechel ◽  
Oleksandr O. Zhdanov
Keyword(s):  
Heat Treatment ◽  
Fine Structure ◽  
Before And After ◽  
Steel 20

scholarly journals The Lamellar Systems of Cytoplasmic Membranes in Dividing Spermatogenic Cells of Drosophila virilis

1960 ◽  
Vol 7 (3) ◽  
pp. 433-441 ◽  
Author(s):  
Susumu Ito
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Light And Electron Microscopy ◽  
Primary Spermatocyte ◽  
Drosophila Virilis ◽  
Spermatogenic Cells ◽  
Membrane Systems ◽  
Cytoplasmic Membranes ◽  
Pas Reaction ◽  
Staining Methods

Spermatogenic cells of Drosophila virilis were studied by light and electron microscopy. The persistence of a "nuclear wall" during the meiotic divisions has been reported by a number of early cytologists, but this interpretation has been a subject of debate. Electron micrographs of dividing spermatocytes reveal the presence of multiple layers of paired membranes surrounding the nuclear region. These lamellar membrane systems are not typical of the nuclear envelope, but were interpreted as such by light microscopists. The membranes constituting a pair are separated by an interspace of ∼ 100 A and successive pairs are 200 to 400 A apart. These spacings are similar but not identical to those found in the lamellar systems of the Golgi complex. The cisternae of the endoplasmic reticulum in this material are devoid of attached ribonucleoprotein particles, are more precisely ordered than in vertebrate cells, and show a uniform, narrow intracisternal space of ∼ 100 A. The conspicuous asters appear to be made up of similar paired membranes radiating from the centriolar region. The primary spermatocyte has numerous dictyosomes and a well developed endoplasmic reticulum in cisternal form, but no typical Golgi complex or endoplasmic reticulum is found during the meiotic division stages of metaphase to telophase. Evidence is presented that these cytoplasmic organelles contribute to the formation of the extensive lamellar systems that appear during meiosis. The results of the Golgi silver staining methods and staining tests for phospholipids, basophilia, and the PAS reaction, indicate that the lamellar arrays of membranes present during meiosis are indistinguishable from the Golgi complex in their tinctorial properties.

scholarly journals Fine structure of lipotubuloids (elaioplasts) in Ornithogalum umbellatum L. I.

2015 ◽  
Vol 40 (3) ◽  
pp. 451-465 ◽  
Author(s):  
M. Kwiatkowska
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rotary Motion ◽  
Osmiophilic Granules

The bodies occurring in the ovary epidermis cells of <i>Ornithogalum umbellatum</i>, rich in lipids have been earlier described as elaioplasts. They consist of agglomerations of osmiophilic granules within the cytoplasm, caught in a network of, and interconnected by, a system of interesecting microtubules. These structures have been named lipotubuloids. They translocate in the cell by way of a progressive-rotary motion. Endoplasmic reticulum membranes, ribosomes and very scarse mitochondria and Golgi structures occur within the lipotubuloids.

The fine structure of reproducing Toxoplasma gondii

Parasitology ◽  
1963 ◽  
Vol 53 (3-4) ◽  
pp. 643-649 ◽  
Author(s):  
Emeka G. Olisa
Keyword(s):  
Endoplasmic Reticulum ◽  
United Kingdom ◽  
Fine Structure ◽  
Toxoplasma Gondii ◽  
Binary Fission ◽  
The United Kingdom ◽  
Research Scholarship ◽  
Fixation Techniques ◽  
Different Shapes ◽  
Nigerian Government

1. Different shapes and forms found in Toxoplasma gondii are associated with reproduction and growth. The functions of the toxoneme and the conoid are discussed.2. A new structure, ‘lamella spiralis', is described in relation to the nucleus and the endoplasmic reticulum.3. T. gondii reproduces either by dividing into two (binary fission) or by multiple division (schizogony), and by a type of endogenous budding. In the latter case small portions pinched off from the nucleus are rounded up to form several small organisms named ‘morulae'.The author gratefully acknowledges the interest and valuable suggestions of Dr G. A. Gresham, M.D., who supervised this work; Dr J. M. Davis and Mr F. Allen, who were kind enough to read the manuscript critically, and Mr W. A. Mowlam for his technical help and advice on fixation techniques.This work was carried out during the tenure of a research scholarship awarded by the United Kingdom Department of Technical Co-operation and the Eastern Nigerian Government.

Observations on the Fine Structure of the Eyespot and Associated Organelles in the Dinoflagellate Glenodinium Foliaceum

1969 ◽  
Vol 5 (2) ◽  
pp. 479-493 ◽  
Author(s):  
J. D. DODGE ◽  
R. M. CRAWFORD
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Lamellar Body ◽  
Ventral Side ◽  
Close Packing ◽  
Hexagonal Close Packing ◽  
Osmiophilic Granules ◽  
Algal Groups ◽  
Posterior Direction ◽  
Microtubular System

The eyespot of the marine dinoflagellate Glenodinium foliaceum is a flattened orange structure, more or less trapezoid in shape with an anterior hook-like projection. It is situated on the ventral side of the organism in the vicinity of the flagellar bases at the anterior end of the sulcus. In the electron microscope the eyespot is seen to contain two layers of osmiophilic granules 80-200 nm in diameter which usually show hexagonal close-packing. The eyespot is surrounded by a triple-membraned envelope and is not connected to any other organelle. Adjacent to the eyespot is a distinctive organelle termed the ‘lamellar body’. This consists of a stack of up to 50 flattened vesicles or disks, each 16 nm thick and about 750 nm wide, the whole being orientated in an antero-posterior direction. The lamellae are continuous, at the ends of the stack, with rough endoplasmic reticulum and are joined together by occasional bridges at their edges. The bases of the two flagella lie just ventral to the lamellar body and from them roots arise which pass by the eyespot and join the subthecal microtubular system. The eyespot of Glenodinium is unique both in structure and the presence of the associated lamellar body. It differs from eyespots which have been described from other algal groups and also from the more complex ocellus found in certain dinoflagellates belonging to the order Warnowiaceae. The method by which the eyespot functions is discussed and it is suggested that unidirectional stimuli could be perceived by shading of the lamellar body.

The polypeptides of rat liver nuclear envelope. II. Comparison of rat liver nuclear membrane polypeptides with those of the rough endoplasmic reticulum

1980 ◽  
Vol 43 (1) ◽  
pp. 269-277
Author(s):  
J.C. Richardson ◽  
A.H. Maddy
Keyword(s):  
Endoplasmic Reticulum ◽  
Rat Liver ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Relative Proportion ◽  
Membrane System ◽  
Membrane Systems ◽  
Nuclear Membranes ◽  
Cytoplasmic Surface ◽  
Triton X

Nuclear envelopes are separated into pore-lamina and membrane sub-fractions by extraction in 2.0% Triton X-100 followed by pelleting of the pore-laminae. The polypeptides of these subfractions are then compared with those from isolated rough endoplasmic reticulum. The dispositions of individual polypeptides in the cytoplasmic surface of nuclear envelopes and rought endoplasmic reticulum were studied by lactoperoxidase-catalysed iodination. These studies show that although the nuclear membranes exhibit several homologies with the Triton-soluble polypeptides of the rough endoplasmic reticulum the relative proportion of individual polypeptides within the two systems are very largely different. The cytoplasmic surfaces of the 2 membrane systems show only 2 obvious homologies at 105 000 and 15 000 mol. wt and the overall impression is that, at least in rat liver, the outer nuclear membrane is very substantially differentiated from rough endoplasmic reticulum. It is concluded that the nuclear membranes may not be regarded as a mere continuum of the endoplasmic reticulum, but should be seen as a highly specialized membrane system in their own right.

The Fine Structure of the Respiratory Tree in Cucumaria

1964 ◽  
Vol s3-105 (69) ◽  
pp. 7-11
Author(s):  
WILLIAM L. DOYLE ◽  
G. FRANCES McNIELL
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Fine Structure ◽  
Epithelial Cells ◽  
Secretory Activity ◽  
Muscle Fibres ◽  
Coelomic Epithelium ◽  
Free Surfaces ◽  
Respiratory Tree ◽  
Synchronous Contraction

The delicate tubules of the respiratory tree consist of 4 layers: a lining epithelium, a thick mucoid layer containing collagenous filaments, a smooth muscle net, and a coelomic epithelium. The free surfaces of both epithelia have well developed plasmodesms. Amoebocytes are present in all layers and the spherules of one type are considered to be precursors of the mucoid substance; another amoebocyte may be a fibroblast. Perpendicularly oriented smooth muscle fibres, as well as those parallel to each other, are linked by desmosomes ensuring synchronous contraction. Secretory activity is evident in distended cisternae of the endoplasmic reticulum of certain epithelial cells and in the vacuoles of the lining epithelium.

Effects of Hormones on the Polysaccharide-Synthesizing Membrane Systems of Lettuce Pith

1974 ◽  
Vol 16 (2) ◽  
pp. 433-443
Author(s):  
K. WRIGHT ◽  
D. J. BOWLES
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Walls ◽  
Membrane Systems ◽  
Radioactive Precursor

Changes have been induced in the polysaccharides laid down in the cell walls of lettuce pith by administration of the hormones auxin and zeatin. This polysaccharide derives from the membrane systems of the cells and radioactive precursor has been used to follow the accompanying changes which occurred in the polysaccharide contained within isolated Golgi and endoplasmic reticulum fractions. Zeatin-induced division and differentiation was accompanied by up to 12-fold increases in the amount of radioactivity in polysaccharide of isolated membrane fractions, and the pattern of distribution of label between the sugars of this polysaccharide was qualitatively different in the presence of zeatin. The change in this pattern was evident in the Golgi fraction at an earlier stage in the induction of the response than that in the endoplasmic reticulum.

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