scholarly journals CHROMATOPHORE DEVELOPMENT, PITS, AND OTHER FINE STRUCTURE IN THE RED ALGA, LOMENTARIA BAILEYANA (HARV.) FARLOW

1962 ◽  
Vol 12 (3) ◽  
pp. 553-569 ◽  
Author(s):  
G. Benjamin Bouck
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Higher Plants ◽  
Red Alga ◽  
Cellular Structures ◽  
Secretory Function ◽  
Thin Sections ◽  
Floridean Starch ◽  
Oriented Parallel

Thin sections of the red alga, Lomentaria baileyana, a tubular member of the Rhodymeniales, were examined after permanganate fixation and Araldite embedding. Many of the cellular structures in Lomentaria were found to be similar to analogous structures in animals and higher plants. However, in the walls between cells are modified areas generally known as pits which are unique to the higher orders of red algae (Florideae). In this study the pits were found to consist of a plug-like structure surrounded by an uninterrupted membrane apparently continuous with the plasma membrane. Examination of the chromatophore revealed a characteristic limiting membrane, a relatively sparse distribution of plates, no grana, and a single disc apparently oriented parallel to the limiting membrane. In addition to their origin from non-lamellate proplastids, chromatophores were found capable of division by simple constriction. Floridean starch grains were observed outside the chromatophore and the possibility of an association of the first formed grains with portions of the endoplasmic reticulum is considered. Gland cells seem to have a high proportion of Golgi components (dictyosomes), and are believed to have some kind of secretory function. Many of the Golgi vesicles seem to open on the wall and presumably discharge their contents.

scholarly journals The Fine Structure of Streptomyces coelicolor

1960 ◽  
Vol 7 (3) ◽  
pp. 479-487 ◽  
Author(s):  
Audrey M. Glauert ◽  
David A. Hopwood
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Streptomyces Coelicolor ◽  
Nuclear Material ◽  
Tubular Structures ◽  
Thin Sections ◽  
Cytoplasmic Structure ◽  
Intracytoplasmic Membranes ◽  
Membranous Component

Colonies and spore suspensions of Streptomyces coelicolor were fixed by the method of Kellenberger, Ryter, and Séchaud (1958) and embedded in methacrylate or araldite. Thin sections were cut with an A. F. Huxley microtome and examined in a Siemens' Elmiskop I. At all stages of development the hyphae of Streptomyces coelicolor have an extensive membranous component in the cytoplasm. The membranes are continuous with the plasma membrane and have a variety of configurations at different places in the hyphae. Tubular structures, vesicles, and parallel stacks of membranes are seen. In some areas concentric layers of membranes form whorled structures which are particularly frequent in the region of developing cross-walls and within maturing spores. In the spores membranous structures often lie embedded in the nuclear material. In disintegrating hyphae the intracytoplasmic membranes round off into small vesicles and remain when the rest of the cytoplasmic structure has gone. In the absence of typical mitochondria and other cytoplasmic membranous structures it is possible that the membranous component of the cytoplasm of Streptomyces coelicolor may perform the functions of the endoplasmic reticulum and/or the mitochondria of higher cells.

scholarly journals Growth and Differentiation of the Golgi Apparatus in the Red Alga, Callithamnion Roseum

1974 ◽  
Vol 14 (3) ◽  
pp. 633-655
Author(s):  
EVA KONRAD HAWKINS
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Red Algae ◽  
Developmental Stages ◽  
Spore Wall ◽  
Red Alga ◽  
Wall Formation ◽  
Golgi Vesicles

The fine structure of the Golgi apparatus during development of tetrasporangia of Calli-thamnion roseum is described. Dictyosomes and associated vesicles of 4 developmental stages of sporangia are examined. The wall of sporangia exhibits a heretofore unseen cuticle in red algae. Development of the spore wall and a new plasma membrane around spores occurs through fusion of adjacent Golgi vesicles along the periphery of cells. Observations are discussed in relation to wall formation and expansion of tetrads and in comparison with other work on growth and differentiation of the Golgi apparatus.

Polymorphous endocytotic organelles in the receptor-mediated endocytosis of gold-labelled alpha 2-macroglobulin complexes by human fibroblasts

1985 ◽  
Vol 75 (1) ◽  
pp. 411-421
Author(s):  
B. Van der Schueren ◽  
D. Gasser ◽  
P. Marynen ◽  
F. Van Leuven ◽  
G. David ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Human Fibroblasts ◽  
Cellular Structures ◽  
Multivesicular Bodies ◽  
Staining Reaction ◽  
Human Skin Fibroblasts ◽  
Thin Sections ◽  
Receptor Mediated Endocytosis ◽  
Gold Label

The receptor-mediated endocytosis of gold-labelled alpha 2-macroglobulin complexes with trypsin or methylamine (alpha 2M-T-Au or alpha 2M-MA-Au) was studied by electron microscopy in human skin fibroblasts. The gold label was found in coated structures and very small tubules as well as in tubulovesicular structures and in multivesicular bodies/lysosomes. Thick sections (200 nm), but especially serial thin sections, clearly showed the polymorphic character of the cellular structures involved in endocytosis. Numerous intercommunications were particularly obvious between the tubulovesicular structures, the larger vesicles and the multivesicular bodies (MVB). Continuities between MVBs and endoplasmic reticulum and interconnections between MVBs were also observed. The specificity of the staining reaction was confirmed by indirect labelling of intracellular alpha 2M by polyclonal and by monoclonal antibodies on ultracryosections. These findings are discussed in relation to observations made on epithelial cells with other ligands.

The fine structure of Sphaerotilus nutans

1973 ◽  
Vol 19 (3) ◽  
pp. 309-313 ◽  
Author(s):  
Judith F. M. Hoeniger ◽  
H.-D. Tauschel ◽  
J. L. Stokes
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Lateral Position ◽  
Thin Sections ◽  
Liquid Cultures ◽  
Sphaerotilus Natans ◽  
Stationary Liquid ◽  
Basal Disk ◽  
Polar Organelle

Sphaerotilus natans developed sheathed filaments in stationary liquid cultures and motile swarm cells in shaken ones. Electron microscopy of negatively stained preparations and thin sections showed that the sheath consists of fibrils. When the filaments were grown in broth with glucose added, the sheath was much thicker and the cells were packed with granules of poly-β-hydroxybutyrate.Swarm cells possess a subpolar tuft of 10 to 30 flagella and a polar organelle which is usually inserted in a lateral position and believed to be ribbon-shaped. The polar organelle consists of an inner layer joined by spokes to an accentuated plasma membrane. The flagellar hook terminates in a basal disk, consisting of two rings, which is connected by a central rod to a second basal disk.

Ultrastructural changes induced in zoospores of Lagenidium callinectes by exposure to Captan

1979 ◽  
Vol 57 (20) ◽  
pp. 2116-2121 ◽  
Author(s):  
D. G. Ruch ◽  
C. E. Bland
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Nuclear Matrix ◽  
Active Component ◽  
Marine Fungus ◽  
Toxic Action ◽  
Ultrastructural Changes ◽  
Mitochondrial Matrix ◽  
Growth Development

The effects of the fungicide Captan on growth, development, and fine structure of the marine fungus Lagenidium callinectes Couch are studied. At the minimum lethal concentration (LC100) of Captan for L. callinectes (3.2 ppm active component), zoospores exposed for 30 min failed to encyst or germinate. Ultrastructural changes caused by exposure to Captan included "washing-out" of the mitochondrial matrix and disappearance of many of the cristae, clumping of the chromatin and disappearance of the nuclear matrix, and swelling of the cisternae of the endoplasmic reticulum. Longer exposure of zoospores to Captan resulted ultimately in breakdown of the plasma membrane. These observations were in agreement with those of previous studies which indicated that the toxic action of Captan occurs primarily in mitochondria.

scholarly journals The Fine Structure of the Rod-Bipolar Cell Synapse in the Retina of the Albino Rat

1958 ◽  
Vol 4 (4) ◽  
pp. 459-466 ◽  
Author(s):  
Aaron J. Ladman
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Bipolar Cell ◽  
Plasma Membranes ◽  
Lower Pole ◽  
Albino Rat ◽  
Cytoplasmic Vesicles ◽  
Thin Lamella ◽  
Cell Synapse

The fine structure of the rod-bipolar synapse is described and illustrated. Each rod spherule possesses a large, single, oval or elongate mitochondrion approximately 0.5 x 2.0 microns. Surrounding the mitochondrion are elements of agranular endoplasmic reticulum. The bipolar dendrite projects into the lower pole of the spherule and usually terminates in two lobes separated by a cleft. The plasma membranes appear dense and thicker in the region of the synapse. In the rod spherule cytoplasm, contiguous with the plasma membrane is a dense, slightly concave arciform structure, the rod arciform density, extending from the base of the bipolar bifid process through the cleft to an equivalent point on the opposite side. Also within the spherule, and external (towards the sclera) to the rod arciform density, is a parallel, dense, thin lamella, the rod synaptic lamella. This is approximately 25 mµ in thickness and 400 mµ in width at its widest extent. This halfmoon-shaped plate straddles the cleft between the two lobes of the bipolar process. The lamella appears to consist of short regular rodlets or cylinders 5 to 7 mµ in diameter, oriented with their long axes perpendicular to the plane of the lamella. Minute cytoplasmic vesicles found in the cytoplasm of both the rod spherule and the bipolar terminal are most abundant near the rod synaptic lamella.

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.

scholarly journals Studies on the Comparative Physiology of Chara Australis II. The Fine Structure of The Protoplast

1964 ◽  
Vol 17 (2) ◽  
pp. 372 ◽  
Author(s):  
TC CHAMBERS ◽  
FV MERCER
Keyword(s):  
Fine Structure ◽  
Unit Volume ◽  
Higher Plants ◽  
Linear Phase ◽  
Comparative Physiology ◽  
Thin Sections ◽  
Golgi Bodies ◽  
Constant Structure ◽  
Parenchyma Cells ◽  
Chara Australis

The fine structure of the internodal cells of G. australis in the linear phase of cell expansion is described from electron micrographs of thin sections of osmium. and permanganate-fixed material. . The static picture obtained is basically similar to that of the parenchyma cells of higher plants as established by electron-microscope observations. A unit volume of protoplast has the same fine structure in cells ranging from 1 em to many centimetres in length, and contains cell wall, plasmalemma, tonoplast, endoplasmic reticulum, golgi bodies, micro somes, mitochondria, chloro_ plasts, nuclei, and other inclusions. This constant structure may account for the constant metabolism per unit volume of protoplast during the linear phase of development. A brief discussion of the possible significance of this picture of the structure of the internodal protoplast to the functional activity of the cell is given.

Ultrastructure of the fusion cell in Faucheocolax attenuata Setch. (Rhodophyta, Rhodymeniales)

1984 ◽  
Vol 72 (1) ◽  
pp. 307-319
Author(s):  
S.G. Delivopoulos ◽  
P. Kugrens
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Basal Cell ◽  
Red Algae ◽  
Helical Structure ◽  
Cell Types ◽  
Floridean Starch ◽  
Auxiliary Cell ◽  
Shaped Cell ◽  
Fusion Cell

The fusion cell in Faucheocolax attenuata Setch. is a highly lobed, thick-walled, multinucleate and irregularly shaped cell originating from the basal cell of the auxiliary cell branch. The formation of the fusion cell occurs by an incorporation of vegetative cells into the basal cell, after dissolution of septal plugs between these cell types. Thus the fusion cell is a syncytium containing only haploid nuclei, as well as unusual mitochondria and plastids. Mitochondria lack cristae and instead contain a tubular helical structure. Plastids are atypical with regard to thylakoid organization in red algae, because they lack the peripheral thylakoid and their photosynthetic thylakoids are aggregated to one side. In addition, they contain large osmiophilic bodies. Nuclear envelopes appear to produce large quantities of membrane cisternae. Floridean starch is absent and the cytoplasm contains few ribosomes. The plasma membrane is irregular and endoplasmic reticulum cisternae are situated parallel to it. Bundles of putative microfilaments were commonly found in nuclei and the cytoplasm. Structural evidence does not support any meristematic, nutritive or secretory functions previously ascribed to fusion cells in other genera.

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.

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