Uredospore development in Puccinia graminis

1969 ◽  
Vol 47 (12) ◽  
pp. 2061-2064 ◽  
Author(s):  
M. A. Ehrlich ◽  
H. G. Ehrlich
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Wall Layer ◽  
Tangential Section ◽  
Puccinia Graminis ◽  
Lipid Bodies ◽  
External Wall ◽  
Additional Information ◽  
Spine Development

The present paper reports a number of electron microscope observations on the protoplasm and walls of developing spores which provide additional information on uredospore wall and spine development and on the fine structure of organelles, particularly of mitochondria and endoplasmic reticulum and of lipid bodies in developing spores. Micrographs of partially extracted uredospore walls and of chromium-shadowed extracted sections demonstrate the architecture of the wall as seen in cross and tangential section. Three distinct wall zones are clearly visible with the external wall layer forming the boundary of the germinal pore.

The fine structure and development of chlamydospores of Fusarium oxysporum

1972 ◽  
Vol 18 (7) ◽  
pp. 997-1002 ◽  
Author(s):  
I. L. Stevenson ◽  
S. A. W. E. Becker
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Fine Structure ◽  
Electron Microscope ◽  
Cell Surface ◽  
Outer Layer ◽  
Outer Wall ◽  
Wall Layer ◽  
Thin Sections ◽  
Hyphal Wall

Methods have been developed for the rapid, reproducible induction of high-density populations of F. oxysporum chlamydospores. On transferring washed pregerminated conidia to a simple two-salts medium, chlamydospore morphogenesis was evident by 12 h and masses of mature spores could be harvested at the end of 4 days. Electron-microscope studies of thin sections of mature chlamydospores reveal a thick triple-layered cell wall. The cytoplasm contains, in addition to large lipid deposits, a nucleus, mitochondria, and endoplasmic reticulum all typical of fungal cells. Chlamydospores of F. oxysporum exhibit two distinct types of cell surface in thin section. The outer wall layer of two of the isolates studied was smooth-surfaced while the outer layer of the two other isolates was distinctly fibrillose. Some evidence is presented suggesting that the fibrillose material arises through the partial breakdown of the original hyphal wall.

scholarly journals THE FINE STRUCTURE OF ASTROCYTES IN THE CEREBRAL CORTEX AND THEIR RESPONSE TO FOCAL INJURY PRODUCED BY HEAVY IONIZING PARTICLES

1965 ◽  
Vol 25 (2) ◽  
pp. 141-157 ◽  
Author(s):  
David S. Maxwell ◽  
Lawrence Kruger
Keyword(s):  
Cerebral Cortex ◽  
Fine Structure ◽  
Electron Microscope ◽  
Reactive Astrocytes ◽  
Lipid Bodies ◽  
Particle Irradiation ◽  
Fibrous Astrocytes ◽  
Primitive Forms ◽  
Focal Injury ◽  
Glycogen Particles

Normal and reactive astrocytes in the cerebral cortex of the rat have been studied with the electron microscope following focal alpha particle irradiation. The presence of glycogen and approximately 60-A fibrils identify astrocyte cytoplasm in formalin-perfused tissue. The glycogen particles facilitate the identification of small processes and subpial and perivascular end-feet. Both protoplasmic and fibrous astrocytes contain cytoplasmic fibrils and should be distinguished on the basis of the configuration of their processes and their distribution. Acutely reactive astrocytes are characterized by a marked increase in the number of glycogen granules and mitochondria from the first day after irradiation. These cells later hypertrophy and accumulate lipid bodies and increased numbers of cytoplasmic fibrils. The glial "scar" consists of a greatly expanded volume of astrocyte cytoplasm filled with fibrils and displays no signs of astrocyte death, reversion to primitive forms, or extensive multiplication.

scholarly journals THE FINE STRUCTURE OF NEURONS

1955 ◽  
Vol 1 (1) ◽  
pp. 69-88 ◽  
Author(s):  
Sanford L. Palay ◽  
George E. Palade
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Cerebellar Cortex ◽  
Dorsal Root Ganglia ◽  
Medulla Oblongata ◽  
Dorsal Root ◽  
Thin Sections ◽  
Lipid Inclusions ◽  
Nissl Substance

1. Thin sections of representative neurons from intramural, sympathetic and dorsal root ganglia, medulla oblongata, and cerebellar cortex were studied with the aid of the electron microscope. 2. The Nissl substance of these neurons consists of masses of endoplasmic reticulum showing various degrees of orientation; upon and between the cisternae, tubules, and vesicles of the reticulum lie clusters of punctate granules, 10 to 30 mµ in diameter. 3. A second system of membranes can be distinguished from the endoplasmic reticulum of the Nissl bodies by shallower and more tightly packed cisternae and by absence of granules. Intermediate forms between the two membranous systems have been found. 4. The cytoplasm between Nissl bodies contains numerous mitochondria, rounded lipid inclusions, and fine filaments.

Fine Structure Study of Pollen Development in Haemanthus katherinae Baker

1971 ◽  
Vol 8 (2) ◽  
pp. 317-329
Author(s):  
JEAN M. SANGER ◽  
W. T. JACKSON
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Final Stage ◽  
Structure Study ◽  
Pollen Grain ◽  
Developmental Period ◽  
Vegetative Nucleus ◽  
Lipid Bodies ◽  
Starch Granules ◽  
Flat Cisternae

The newly formed vegetative cell of the pollen grain of the African blood lily has a spheroidal nucleus, few dictyosomes, and a small amount of endoplasmic reticulum. Plastids are smaller than those of the microspore and usually lack starch granules. Mitochondria and lipid bodies are more numerous than they were in the microspores, but their appearance is unchanged. As the pollen grain matures, the vegetative nucleus becomes irregular in shape. There is a dramatic increase in the number of dictyosomes, starch accumulates in the plastids, and a moderately well developed system of endoplasmic reticulum appears in the form of flat cisternae. In the developmental period immediately preceding anthesis, the vegetative nucleus becomes lobate and small nucleoli replace the large nucleoli present earlier. Plastids lose their starch, lipid bodies disappear, and the endoplasmic reticulum becomes vesicular in this final stage before germination.

Fine structure and early fertilization changes of the animal pole in eggs of the river lamprey, Lampetra fluviatilis

Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 319-326
Author(s):  
Lennart Nicander ◽  
Björn A. Afzelius ◽  
Inger Sjödén
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Marine Invertebrates ◽  
Bivalve Mollusc ◽  
Annulate Lamellae ◽  
Animal Pole ◽  
River Lamprey ◽  
Vertebrate Eggs

Fertilization is accompanied by changes in the structure of the egg cytoplasm (cf. Rothschild, 1958; Raven, 1961). At the level of fine structure such changes have mainly been studied in some marine invertebrates with small eggs that can easily be fertilized in vitro (Pasteels & de Harven, 1963; Schäfer, 1966). Vertebrate eggs are less favourable in this respect, but electron microscope studies have been made on eggs of mammals (Fléchon, 1966; Zamboni & Mastroianni, 1966; Zamboni, Mishell, Bell & Baca, 1966) and Xenopus (van Gansen, 1966). Changes generally observed soon after fertilization include the formation of polysomes or an increase in their number, a hypertrophy of the Golgi complexes, and the appearance of granulated endoplasmic reticulum and annulate lamellae. Afzelius (1957) observed the dispersal of mitochondria in fertilized sea-urchin eggs. Pasteels & de Harven (1963) reported that the structure and distribution of cytoplasmic organelles in eggs of the bivalve mollusc, Barnea Candida, are not altered by fertilization.

FINE STRUCTURE OF WHEAT STEM RUST UREDOSPORES

1964 ◽  
Vol 42 (11) ◽  
pp. 1503-1508 ◽  
Author(s):  
P. G. Williams ◽  
G. A. Ledingham
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Higher Plants ◽  
Puccinia Graminis ◽  
Resting Cells ◽  
Oil Bodies ◽  
Wheat Stem Rust ◽  
Cytoplasmic Structures ◽  
Vacuolar Membranes ◽  
Germ Tubes

The fine structure of uredospores and germ tubes of Puccinia graminis f. sp. trilici is described from electron micrographs of cells fixed in KMnO4. In terms of their principal cytoplasmic structures (nuclei, mitochondria, endoplasmic reticulum, and protoplasmic and vacuolar membranes) these cells bear a general resemblance to other fungi and higher plants but differences between resting cells and germ tubes were noted in the size of oil bodies and the structure and extent of the endoplasmic reticulum.

Considerations in Making Stereo Micrographs With the Scanning Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 234-235
Author(s):  
E. R. Walter
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Three Dimensional ◽  
Spatial Relationships ◽  
Additional Information ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The information obtainable with the scanning electron microscope can often be increased severalfold through the use of stereomicrograph pairs. Not only is the detail which can be observed the equivalent of a 2X increase in magnification over that apparent in a single micrograph, but, threedimensional spatial relationships are more accurately preserved. This is especially true where protruding or pyramided fine structure and/or gross reentrance exists. Since stereo micrographs are conveniently obtained with most scanning electron microscopes, it is generally desirable to add the additional information they offer whenever the three-dimensional relationships present in the specimen'are not readily apparent.

Differentiation of Neurosensory Cells in Hydra

1969 ◽  
Vol 5 (3) ◽  
pp. 699-726
Author(s):  
LOWELL E. DAVIS
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Basal Body ◽  
Neurosecretory Cells ◽  
Nerve Cells ◽  
Granular Endoplasmic Reticulum ◽  
Structural Variations ◽  
Intercellular Bridges ◽  
Undifferentiated Cells

The differentiation of neurosensory cells in Hydra has been studied at the level of the electron microscope. These cells arise from interstitial cells (undifferentiated cells) and not from pre-existing nerve cells. Furthermore, there is no evidence to suggest that neurosensory cells represent a stage in the development of other nerve cells, i.e. ganglionic and neurosecretory cells. Major cytoplasmic changes in fine structure during differentiation include development of a cilium and associated structures (basal body, basal plate, rootlets), development of microtubules and at least two neurites, increase in Golgi lamellae and formation of dense droplets typical of neurosecretory droplets, structural variations in mitochondria and a decrease in the number of ribosomes. Granular endoplasmic reticulum is characteristically poorly developed in all stages of differentiation, including the mature neurosensory cell. Nuclear and nucleolar changes also occur during differentiation but these are less dramatic than the cytoplasmic events. The possibility of neurosensory cells being bi- or multiciliated and the presence of intercellular bridges between these cells are considered. The function of neurosensory cells is discussed briefly in relation to the function of the cilium and neurosecretory droplets.

scholarly journals FINE STRUCTURE OF THE LARVAL ANURAN EPIDERMIS, WITH SPECIAL REFERENCE TO THE FIGURES OF EBERTH

1961 ◽  
Vol 10 (3) ◽  
pp. 425-435 ◽  
Author(s):  
George B. Chapman ◽  
Alden B. Dawson
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Free Surface ◽  
Electron Microscope ◽  
Fibrous Material ◽  
Distal Region ◽  
Epidermal Layer ◽  
Basal Plasma Membrane ◽  
Basal Plasma ◽  
Ultrathin Sections

Small pieces of skin from 8 cm long Rana clamitans larvae were fixed in OsO4, washed, dehydrated, and embedded in a methacrylate mixture. Ultrathin sections were cut on a Porter-Blum ultramicrotome and were examined in an RCA electron microscope, type EMU 2D. The sections showed that aggregates of fibrous material in the cells of the inner layer of epidermal cells are identical in disposition and size with the classical figures of Eberth. It is conclusively shown that these figures do not arise from an aggregation of mitochondrial filaments. The tendency of the fibrils to concentrate on attachment points, or thickenings of the basal plasma membrane, is noted. It is also observed that numerous mitochondria are located in the distal region of the cells of the outer layer of epidermis in association with the secretory vacuoles. Microvilli are seen occasionally on the free surface of the skin. Cisternae are found only in the cells of the outer epidermal layer, while vesicular endoplasmic reticulum is found in the cells of both epidermal layers.

scholarly journals The Fine Structure of a Multiterminal Innervation of an Insect Muscle

1959 ◽  
Vol 5 (2) ◽  
pp. 241-244 ◽  
Author(s):  
George A. Edwards
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Electron Microscope ◽  
Basement Membrane ◽  
Neuromuscular Junctions ◽  
Abdominal Muscle ◽  
Membrane Material ◽  
Detailed Structure ◽  
Insect Muscle

The detailed structure of nerve branches, neuromuscular junctions, and muscle fibers of a multiterminal innervation of cockroach abdominal muscle has been studied with the electron microscope. The muscle fiber is of the banded myofibril type; with paired mitochondria and abundant endoplasmic reticulum. The peripheral nerve branches are multiaxonal with large central axon and several small peripheral tunicated axons. Tracheoblasts closely accompany the nerve branches. The multiple neuromuscular junctions show typical axonal vesicles, muscle aposynaptic granules, and close plasma membrane apposition with no interposition of basement membrane material.

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