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

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.

1976 ◽  
Vol 21 (3) ◽  
pp. 437-448
Author(s):  
A.S. Breathnach ◽  
M. Gross ◽  
B. Martin ◽  
C. Stolinski

Fixed (glutaraldehyde, 3%) and unfixed specimens of rat buccal epithelium, striated muscle, and liver, were cryoprotected with glycerol, freeze-fractured, and replicated without sublimation. A comparison of fracture faces of general plasma membranes, nuclear membranes, mitochondrial membranes, and membranes of rough endoplasmic reticulum revealed no significant differences as between fixed and unfixed material. Apart from some membranes of liver endoplasmic reticulum, there was no evidence of aggregation or redistribution of intramembranous particles in the unfixed material. The results demonstrate that chemical prefixation of tissues for freeze-fracture is not always necessary, or even desirable, and that glycerol may not be as deeply or directly implicated in particle aggregation as previously thought. Fixation with glutaraldehyde alters the cleaving behaviour of plasma membrane at desmosomes and tight junctions, but not at gap junctions.


1977 ◽  
Vol 55 (9) ◽  
pp. 1221-1235 ◽  
Author(s):  
D. J. S. Barr ◽  
V. E. Hartmann

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.


Development ◽  
1978 ◽  
Vol 43 (1) ◽  
pp. 247-261
Author(s):  
Par Anne-Marie Bautz

The morphogenesis of the abdominal epidermis in Calliphora erythrocephala begins by a cellular proliferation which proceeds slowly in larvae and rapidly in pupae. This allows histoblasts to glide and invade the whole abdominal surface. As soon as the new epidermal sheet has become continuous, differentiation begins. Generalized epidermal cells show an intense activity which leads to the deposition of imaginal cuticle from the 6th day after pupation onwards. After cuticle deposition they darken and become inactive although they remain alive, even after emergence. Trichogen and tormogen cells are even more active than generalized epidermal cells, especially the trichogen cell in which polyribosomes and microtubules are abundant. The former are possibly involved in microtubule synthesis. After cuticle deposition the trichogen and tormogen cells undergo degeneration. Their nuclei contract, rough endoplasmic reticulum breaks down and cytoplasm breaks up into fragments through infoldings which proliferate from the plasma membrane. Finally only generalized epidermal cells and sensory cells remain alive in the adult.


1980 ◽  
Vol 43 (1) ◽  
pp. 269-277
Author(s):  
J.C. Richardson ◽  
A.H. Maddy

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.


1992 ◽  
Vol 78 (3) ◽  
pp. 190-197 ◽  
Author(s):  
Manrico Morroni ◽  
Giordano Ripa ◽  
Guido Bolognesi ◽  
Pietro Leoni ◽  
Saverio Cinti

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.


1984 ◽  
Vol 98 (1) ◽  
pp. 29-34 ◽  
Author(s):  
M R Torrisi ◽  
P Pinto da Silva

We used thin-section fracture-label to determine the distribution of wheat-germ agglutinin binding sites in intracellular membranes of secretory and nonsecretory rat tissues as well as in human leukocytes. In all cases, analysis of the distribution of wheat germ agglutinin led to the definition of two endomembrane compartments: one, characterized by absence of the label, includes the membranes of mitochondria and peroxisomes as well as those of the endoplasmic reticulum and nuclear envelope; the other, strongly labeled, comprises the membrane of lysosomes, phagocytic vacuoles, and secretory granules, as well as the plasma membrane. The Golgi apparatus was weakly labeled in all studied tissues.


1974 ◽  
Vol 60 (2) ◽  
pp. 460-472 ◽  
Author(s):  
David H. DeHeer ◽  
Merle S. Olson ◽  
R. Neal Pinckard

The induction of acute hepatocellular necrosis in rats resulted in the production of complement fixing, IgM autoantibodies directed toward inner and outer mitochondrial membranes, microsomal membrane, lysosomal membrane, nuclear membrane, cytosol, but not to plasma membrane. Utilizing selective absorption procedures it was demonstrated that each subcellular membrane fraction possessed unique autoantigenic activity with little or no cross-reactivity between the various membrane fractions. It is proposed that the development of membrane-specific autoantibodies may provide an immunological marker useful in the differential characterization of various subcellular membranes.


1976 ◽  
Vol 24 (6) ◽  
pp. 713-724 ◽  
Author(s):  
F Roels

In sheep hepatocytes catalase activity was demonstrated both within peroxisomes and within the cytosol. In the cytosol the catalase reaction product is contiguous to the plasma membrane and surrounds the nuclei, rough endoplasmic reticulum, cisternae, mitochondria and Golgi apparatus. This is the first cytochemical demonstration of guine extraperoxisomal catalase. No catalase reaction product was seen in the cytosol of nonparenchymal cells. To demonstrate catalase, both glutaraldehyde and formaldehyde fixation were used, followed by a diaminobenzidine technique modified from Novikoff and Goldfischer. Control reactions were performed to distinguish catalase reaction product from adsorption of oxidized diaminobenzidine and from precipitate due to oxidase-, peroxidase- or heat-stable peroxidatic activities. The results were evaluated in the light and electron microscopes.


1993 ◽  
Vol 41 (5) ◽  
pp. 649-656 ◽  
Author(s):  
F W Kan

Previous freeze-fracture experiments using either glutaraldehyde-fixed and cryoprotected specimens or unfixed rapid-frozen samples led to the proposal that cylindrical strands of the tight junction (TJ) observed in freeze-fracture preparations are inverted cylindrical micelles made up of membrane lipids and, possibly, membrane proteins. However, no one has yet been able to directly label the structural fibrils of the TJ. To test the hypothesis that TJ strands observed on freeze-fracture preparations are composed at least partially of lipids, we have combined the phospholipase A2-gold and the fracture-label techniques for localization of phospholipids. Phospholipase A2, purified from bee venom, was adsorbed on gold particles and used for specific labeling of its substrate. Phospholipase A2-colloidal gold (PLA2-CG) complex was applied to freeze-fractured preparations of rat exocrine pancreatic cells and testicular Sertoli cells, both of which are known to have extensive TJ complexes on their plasma membranes. Fracture-label replicas of exocrine pancreatic cells revealed specific association of gold particles with TJ fibrils on the protoplasmic fracture-face of the plasma membrane. The majority of these gold particles were observed either directly on the top of the TJ fibrils or adjacent to these cylindrical structures. A high density of PLA2-CG labeling was also observed over the complementary exoplasmic fracture-face of the TJ complex. This intimate association of PLA2-CG labeling with the TJ is particularly evident in the Sertoli cell plasma membrane, where rows of gold particles were observed to be superimposed on parallel arrays of cylindrical strands of the TJ complex. The present findings provide direct cytochemical evidence to support the hypothesis that cylindrical TJ strands observed in freeze-fracture preparations contain phospholipids.


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