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.

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 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.

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.

Ultrastructure of the zoospore of Blastocladia ramosa (Blastocladiales)

1983 ◽  
Vol 61 (12) ◽  
pp. 3502-3513 ◽  
Author(s):  
Wilma L. Lingle ◽  
William E. Barstow
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Enzymatic Digestion ◽  
Storage Material ◽  
Fermentative Metabolism ◽  
Lipid Globule ◽  
Striated Rootlet ◽  
Physiological Differences ◽  
Morphological Differences

Species of Blastocladia, unlike other members of the order Blastocladiales, have an obligately fermentative metabolism. The ultrastructure of the zoospores of Blastocladia ramosa is described and compared with that of zoospores of aerobic members of the Blastocladiales. Zoospores of Blastocladia ramosa are structurally similar to other blastocladialean zoospores in that they have (i) a nuclear cap composed of aggregated ribosomes delimited by an envelope of endoplasmic reticulum; (ii) a posteriorly located nucleus; (iii) nine sets of microtubules that surround the nucleus and nuclear cap; and (iv) a striated rootlet associated with the kinetosome. Zoospores of Blastocladia ramosa differ by having mitochondria with unusual fine structure and by lacking microbodies and microbody – lipid globule complexes. As shown by enzymatic digestion and staining, glycogen appears to be the primary storage material in the zoospore. Structures which resemble water expulsion vacuoles are present. The morphological differences between zoospores of Blastocladia ramosa and other zoospores of the Blastocladiales appear to be related to physiological differences.

scholarly journals OBSERVATIONS ON THE DEVELOPMENT OF ERYTHROCYTES IN MAMMALIAN FETAL LIVER

1962 ◽  
Vol 14 (2) ◽  
pp. 235-254 ◽  
Author(s):  
Joseph A. Grasso ◽  
Hewson Swift ◽  
G. Adolph Ackerman
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Nuclear Envelope ◽  
Cell Size ◽  
Marked Decrease ◽  
Fetal Liver ◽  
Hepatic Parenchyma ◽  
Hemoglobin Synthesis ◽  
Hepatic Cells ◽  
Eventual Loss

The fine structure of the erythrocyte during development in rabbit and human fetal liver has been studied. A morphologic description of representative erythropoietic cells and their relationship to the hepatic parenchyma is presented. Erythrocyte development was accompanied by a decrease in nuclear and cell size, fragmentation and eventual loss of nucleoli, and progressive clumping of chromatin at the nuclear margin. Mitochondria, endoplasmic reticulum, and Golgi elements decreased in size or abundance and eventually disappeared. Ribosome concentration initially increased, but subsequently diminished as the cytoplasm increased in electron opacity, probably through the accumulation of hemoglobin. Similar dense material, interpreted to be hemoglobin, infiltrated the nuclear annuli and, in some cases, appeared to extend into the interchromatin regions. There was a marked decrease in the number of annuli of the nuclear envelope. Possible relationships between nucleus and cytoplasm and of RNA to hemoglobin synthesis are discussed. In rabbits, erythroid and hepatic cells were separated by a 200 to 400 A space limited by the undulatory membranes of the respective cells. Membranes of adjacent erythropoietic cells were parallel and more closely apposed (100 to 200 A). In humans, relationship between various cells exhibited wide variation. Ferritin particles were observed within forming and formed "rhopheocytotic" vesicles.

Effect of thyroxine on the ultrastructure of the hypophyseal proximal pars distalis in Tilapia zillii

1975 ◽  
Vol 53 (6) ◽  
pp. 686-690 ◽  
Author(s):  
John F. Leatherland ◽  
Mohamed Hyder
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Cell Types ◽  
Pars Distalis ◽  
Tilapia Zillii ◽  
Thyroid Axis ◽  
And Control ◽  
Granule Release

The effects of exogenous L-thyroxine on the fine structure of the proximal pars distalis cells were examined in Tilapia zillii. In thyroxine-treated animals the thyrotrophic cells appeared marginally smaller and less active whereas the somatotrophs appeared markedly more active, with increased endoplasmic reticulum, larger mitochondria, and more granule release when compared with the same cell types in control animals. The gonadotrophs were similar in appearance in both thyroxine-treated and control groups.The possible interrelated activity of the somatotrophs and the TSH–thyroid axis is discussed.

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.

The fine structure of the leucocytes of the holothurian, Cucumaria miniata

1977 ◽  
Vol 55 (9) ◽  
pp. 1530-1544 ◽  
Author(s):  
A. R. Fontaine ◽  
Philip Lambert
Keyword(s):  
Stem Cells ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Acid Mucopolysaccharide ◽  
Rough Er

The fine structure of amoebocytes, lymphocytes, and morula cells is described and related to their functions. Three morphological phases (bladder, transitional, and filiform) of the amoebocyte are distinguished. Their surface protrusions and activities are based on microtubule and microfilament systems and the transitional-filiform phases are functionally involved in coelomocyte aggregation. The bladder phase is phagocytic; bladder formation and activities are also microfilament based. Morula cells contain spherules composed of acid mucopolysaccharide and protein. Dilated rough endoplasmic reticulum (ER) cisternae apparently synthesize spherule material which is added by accretion. Lymphocytes have little cytoplasm and relatively few organelles, except for abundant rough ER and free ribosomes. Lymphocytes are probably stem cells for amoebocytes and morulas. These cells are compared with the leucocytes of other echinoderms.

Ultrastructural Studies on the Effects of Korean Panax Ginseng on the Theca Interna of Rat Ovary

1979 ◽  
Vol 07 (04) ◽  
pp. 333-344 ◽  
Author(s):  
Moo Rim Byung
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Golgi Apparatus ◽  
Panax Ginseng ◽  
Lipid Droplets ◽  
Ultrastructural Studies ◽  
Dense Bodies ◽  
Rat Ovary ◽  
Theca Interna ◽  
Morphologic Changes

An investigation was conducted to delineate the fine structure of steroid-producing ovarian theca interna cells following administration of Korean Panax ginseng to rats for 60 days. The cytoplasmic changes were observed in the ginseng-treated theca interna cells, increased number, size and density of the mitochondria, and increased size of the smooth surfaced endoplasmic reticulum, the rough surfaced endoplasmic reticulum and the Golgi apparatus. The nucleus and nucleolus were slightly enlarged and increased numbers of dense bodies were seen whereas lipid droplets were decreased in number. The changes may result from hyperfunction of the steroid-producing cells. Morphologic changes seen may represent stimulating effects on the steroid-producing cells of the theca interna in ginseng-treated animals.

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.

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