Zoospore ultrastructure of Olpidium brassicae and Rhizophlyctis rosea

1977 ◽  
Vol 55 (9) ◽  
pp. 1221-1235 ◽  
Author(s):  
D. J. S. Barr ◽  
V. E. Hartmann
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
The Other ◽  
Lipid Bodies ◽  
Varying Thickness ◽  
Olpidium Brassicae

Zoospore cytology of two lettuce strains (from carrot and plantain) and a cabbage strain of Olpidium brassicae (Woronin) Dang, was compared with that of two isolates of Rhizophlyctis rosea (deBary & Woronin) Fischer. Olpidium brassicae zoospores contain four to six mitochondria grouped around the nucleus: microbodies are closely associated with the nucleus and mitochondria and casually associated with lipid bodies in the cytoplasm; ribosomes are scattered in the cytoplasm; a rhizoplast, 0.65 μm long, extends from kinetosome and non-functional centriole to an area near the nuclear membrane and consists of elongated, very fine fibrils crossed by electron-dense layers (striations) of varying thickness and density; the configuration of the layers of the rhizoplast in the lettuce strains differed from the cabbage strain. Rhizophlyctis rosea zoospores contain many (about 21) mitochondria grouped around the nucleus; elongated microbodies are conspicuous on the posterior and lateral sides of the nucleus and extend into the cytoplasm to lipid bodies; ribosomes are concentrated in an area around the nucleus and are partially enclosed by a net-like and folded arrangement of rough endoplasmic reticulum. Rhizoplasts of R. rosea consist of fine fibrils which extend from the kinetosome and non-functional centriole to the nucleus and are crossed by electron-dense layers; in one isolate the rhizoplast is 0.35 μm long and tapers to a point which is connected by fibrils to a flap of the nucleus in a posteriorly located nuclear pocket; in the other isolate it is 1.35 μm long, and expands into a cone-like segment which abuts onto the flattened, posterior face of the nucleus. The significance of the arrangement of organelles, and in particular the rhizoplast, in chytrid biosystematics is discussed.

Freeze-Fracture Replication of Rough Endoplasmic Reticulum of Mouse Liver Cells

1972 ◽  
Vol 11 (2) ◽  
pp. 477-489
Author(s):  
A. S. BREATHNACH ◽  
C. STOLINSKI ◽  
M. GROSS
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Mouse Liver ◽  
Freeze Fracture ◽  
The Other ◽  
Fracture Face ◽  
Mitochondrial Membranes ◽  
En Face

Fresh, chemically unfixed, glycerinated specimens of mouse liver were examined by the technique of freeze-fracture replication without sublimation (i.e. they were not ‘etched’). Where extensive areas of fractured lamellar membranes of the rough endoplasmic reticulum are revealed en face, 2 types of fracture face are distinguishable. One of these fracture faces (A) is directed towards the cytoplasm, and the other (B) towards the cisternal cavity. A characteristic mosaic, or patchwork pattern of flat areas circumscribed by particles, is evident on both faces, and more clearly so on face B, due to a greater number of more prominent particles. Similar mosaic patterns are revealed on convex faces of the nuclear membrane, and on concave fracture faces of mitochondrial membranes, but are not evident on fracture faces of the plasma membrane. Uncertainty in establishing the exact plane of fracture of membranes in this material, since glycerol is virtually non-sublimable, makes it difficult to assess the significance of these mosaic patterns. The fact that ribosomes are not identifiable on either face of fractured endoplasmic reticulum membranes, gives no certain indication of the plane of fracture.

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.

Ultrastructural Modifications in one Case of Hairy Cell Leukemia during Alpha-Interferon Therapy

1992 ◽  
Vol 78 (3) ◽  
pp. 190-197 ◽  
Author(s):  
Manrico Morroni ◽  
Giordano Ripa ◽  
Guido Bolognesi ◽  
Pietro Leoni ◽  
Saverio Cinti
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Hairy Cell Leukemia ◽  
Interferon Therapy ◽  
Close Contact ◽  
Hairy Cell ◽  
Cell Leukemia ◽  
Ultrastructural Modifications ◽  
Hairy Cells

There are many reports concerning the morphology of hairy cell leukemia (HCL), but, to our knowledge, there are no data on the ultrastructural modifications of HCL during interferon therapy. The ultrastructural modifications of neoplastic cells In peripheral blood in a case of HCL were investigated before and 2 and 4 months after beginning treatment with human lymphoblastoid alpha-interferon. Before therapy, hairy cells displayed the typical cytoplasmic projections, and 4 % contained ribosome-lamellae complexes (RLC) (the cells contained up to 7 RLC). Two months from the beginning of therapy, hairy cells had shorter projections, RLC had disappeared, and tubuloreticular structures (TRS) had appeared in 2.2 % of the elements. Four months from the beginning of therapy, TRS persisted in 2.3 % of hairy cells, cylindrical confronting cisternae (CCC) appeared in 6.8 % of the cells, and uncommon RLC, in close contact with the rough endoplasmic reticulum and nuclear membrane, were found in 1.5 % of the elements. The cells contained up to 3 RLC. Our data confirm that interferon stimulates the synthesis of TRS and CCC, whereas the reappearance of uncommon forms of RLC could reflect their neosynthesis, possibly related to the interferon therapy. The frequent findings of a close contact between RLC and nuclear membrane support the view that RLC are derived not only from rough endoplasmic reticulum, but also from the nuclear membrane.

The Fine Structure of Primordial Germ Cells of the Rat

1973 ◽  
Vol 31 ◽  
pp. 634-635
Author(s):  
E. M. Eddy
Keyword(s):  
Endoplasmic Reticulum ◽  
Life History ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Germ Cells ◽  
Fibrous Material ◽  
Primordial Germ Cells ◽  
The Other ◽  
Large Size ◽  
History Of

Primordial germ cells are readily recognizable in embryos of the rat due to their large size, generally rounded shape and prominent nuclei with uniformly dispersed heterochromatin. They often have blunted pseudopodal processes at one end and small ruffles or trailing processes at the other, characteristics expected from their known ameboid activity- and migratory abilities. Also, the cytoplasm is rich in polyribosomes and contains a modest amount of rough endoplasmic reticulum and the mitochondria are frequently larger and less dense than those of adjacent somatic cells.In addition to these general characteristics, there are features unique to germ cells which allow them to be identified with certainty. These are: 1) small vesicles containing an irregular, dense core and 2) discrete accumulations of fibrous material known as nuage. Both of these features are present in other species and at other times in the life history of germ cells. The dense-cored vesicles have been noted in fetal and early postnatal mouse oogonia and oocytes, and in hamster and rabbit oocytes.

scholarly journals Cytophysiological and ultrastructural modifications induced by cold in the microsporocytes and tapetum of Rhoeo discolor Hance

2014 ◽  
Vol 50 (1-2) ◽  
pp. 89-97 ◽  
Author(s):  
André Souvré ◽  
Louis Albertini ◽  
Hélené Grenet-Auberger
Keyword(s):  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Ultrastructural Modifications

The exposition of <em>Rhoeo discolor</em> to cold induces an alteration of the microsporocytes (PMC) and tapetum ultrastructure. In the young cooled PMC, the mitochondria present short and vesiculate cristae, the stroma of proplasts is clearer and the polyrilbasomes are deteriorated. During the phase tetrads-microspores, the alterations are more important: the chromatin coagulates, the nucleus swells while the nuclear membrane is modified; some large vesicules appear outside of the plasmalemma. In the cooled periplasmodium we can observe many groups of vesicules, mitochondria with dilated cristae, rough endoplasmic reticulum without their ribosomes and a breaking up of inueleoli. Our observations are in correlation with the previous results obtained by autoradiography and photometry, and are discussed with the bibliographical results.

Fine structure of compound eyes of cicindela tranquebarica herbst (coleoptera: cicindelidae)

1978 ◽  
Vol 36 (2) ◽  
pp. 604-605
Author(s):  
Janice E. Kuster
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Cell Nucleus ◽  
The Other ◽  
Pigment Cells ◽  
Compound Eyes ◽  
Basal Bodies ◽  
Protein Deposits ◽  
Corneal Lens

The fine structure of photopic eucone eyes of Cicindela tranquebarica adults was examined using cryofracture SEM, TEM, and freeze-etch techniques. A “subcorneal layer” can be distinguished between the corneal lens and crystalline cone. In surface view (Fig. 1) this layer consists of concave polygons (po). It has parabolic lamellae (lm) of endocuticle consisting of microfibrils (mf) having a chitin core with protein deposits along their lengths (Fig. 2). Two primary pigment cells (lp) are devoid of pigment granules, but are rich in rough endoplasmic reticulum (rer) and surround a crystalline thread (ct) (Fig. 3). Extensions of the crystalline thread form inter-retinular fibers (f) containing microtubules between retinula cells 1/2, 3/4, 5/6, and 7/1 (Figs. 4, 5).Distal to each retinula cell nucleus are two basal bodies (bb), one perpendicular to the other (Fig. 4). The proximal body extends two fibrillar feet which fuse to form a horizontally banded ciliary rootlet which extends the retinula length peripheral to the rhabdom.

Alpha(S1)-casein is required for the efficient transport of beta- and kappa-casein from the endoplasmic reticulum to the Golgi apparatus of mammary epithelial cells

1999 ◽  
Vol 112 (19) ◽  
pp. 3399-3412 ◽  
Author(s):  
E. Chanat ◽  
P. Martin ◽  
M. Ollivier-Bousquet
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Mammary Epithelial Cells ◽  
Whey Proteins ◽  
Mammary Epithelial ◽  
The Other ◽  
Soluble Form ◽  
Beta Casein

In lactating mammary epithelial cells, interaction between caseins is believed to occur after their transport out of the endoplasmic reticulum. We show here that, in alpha(S1)-casein-deficient goats, the rate of transport of the other caseins to the Golgi apparatus is highly reduced whereas secretion of whey proteins is not significantly affected. This leads to accumulation of immature caseins in distended rough endoplasmic reticulum cisternae. Casein micelles, nevertheless, were still observed in secretory vesicles. In contrast, no accumulation was found in mammary epithelial cells which lack beta-casein. In mammary epithelial cells secreting an intermediate amount of alpha(S1)-casein, less casein accumulated in the rough endoplasmic reticulum, and the transport of alpha(S1)-casein to the Golgi occurred with kinetics similar to that of control cells. In prolactin-treated mouse mammary epithelial HC11 cells, which do not express alpha(S)-caseins, endoplasmic reticulum accumulation of beta-casein was also observed. The amount of several endoplasmic reticulum-resident proteins increased in conjunction with casein accumulation. Finally, the permeabilization of rough endoplasmic reticulum vesicles allowed the recovery of the accumulated caseins in soluble form. We conclude that optimal export of the caseins out of the endoplasmic reticulum is dependent upon alpha(S1)-casein. Our data suggest that alpha(S1)-casein interacts with the other caseins in the rough endoplasmic reticulum and that the formation of this complex is required for their efficient export to the Golgi.

scholarly journals The eta isoform of protein kinase C is localized on rough endoplasmic reticulum.

1994 ◽  
Vol 14 (6) ◽  
pp. 3782-3790 ◽  
Author(s):  
K Chida ◽  
H Sagara ◽  
Y Suzuki ◽  
A Murakami ◽  
S Osada ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Rough Endoplasmic Reticulum ◽  
Nuclear Membrane ◽  
Mouse Skin ◽  
Endoplasmic Reticulum Membrane ◽  
Present Observation ◽  
Outer Nuclear Membrane ◽  
Kinase C

The eta isoform of protein kinase C, isolated from a cDNA library of mouse skin, has unique tissue and cellular distributions. It is predominantly expressed in epithelia of the skin, digestive tract, and respiratory tract in close association with epithelial differentiation. We report here that this isoform is localized on the rough endoplasmic reticulum in transiently expressing COS1 cells and constitutively expressing keratinocytes. By the use of polyclonal antibodies raised against peptides of the diverse D1 and D2/D3 regions, we found that immunofluorescent signals were strongest in the cytoplasm around the nucleus and became weaker toward the peripheral cytoplasm. Under immunoelectron microscopic examination, electron-dense signals were located on the rough endoplasmic reticulum and on the outer nuclear membrane which is continuous with the endoplasmic reticulum membrane. However, no signals were detected in the nucleus, inner nuclear membrane, smooth endoplasmic reticulum, Golgi apparatus, mitochondria, or plasma membrane. Treatment of the cells in situ with detergents suggested association of the isoform of protein kinase C with intracellular structures. By immunoblotting, a distinct single band with an M(r) of 80,000 was detected in whole-cell lysate and in rough microsomal and crude nuclear fractions, all of which contain outer nuclear membrane and/or rough endoplasmic reticulum. We further demonstrated the absence of a nuclear localization signal in the pseudosubstrate sequence. The present observation is not consistent with the report of Greif et al. (H. Greif, J. Ben-Chaim, T. Shimon, E. Bechor, H. Eldar, and E. Livneh, Mol. Cell. Biol. 12:1304-1311, 1992).

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