The three cortical membranes of the gregarines. I. Ultrastructural organization of Gregarina blaberae

1983 ◽  
Vol 61 (1) ◽  
pp. 151-174
Author(s):  
J. Schrevel ◽  
E. Caigneaux ◽  
D. Gros ◽  
M. Philippe
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Ultrastructural Organization ◽  
Transmission Electron ◽  
Movement Mechanism ◽  
Cortical Membranes ◽  
Integral Proteins ◽  
Gliding Movement

Gregarines, parasitic protozoa of invertebrates, possess a highly differentiated cell surface, with three cortical membranes and associated structures. Transmission electron microscopy and freeze-fracture reveal the presence of two cytomembranes lying uniformly under the plasma membrane. The density and the distribution of the intramembraneous particles (IMPs) in the plasma membrane of Gregarina blaberae are similar to those reported for other eukaryotic cells. The IMP density is lower in the cytomembranes than in the plasma membrane. The distribution of IMPs in the different fracture faces of the two cytomembranes suggests that they are in topological continuity, forming either side of a flattened vesicle or cisterna. The sizes of the cytomembrane IMPs show a high variability. The nature of the IMPs, both for the plasma membrane and the cytomembrane, is discussed with regard to the integral proteins and glycoproteins of the ghost. The cell surface of G. blaberae exhibits numerous longitudinal folds with three types of cortical membrane-associated structures: 12 nm filaments, an internal lamina, and homogeneous structures described as ‘rippled dense structures’. The 12 nm filaments, running under the cytomembranes along the longitudinal axis of each fold, exhibit the properties of intermediate filaments. Their distribution in mature cells and during the growth process suggests a participation in cell surface morphogenesis. The internal lamina, also localized under the cytomembranes, would stabilize each fold and assure a scaffolding function between the numerous folds. The rippled dense structures, settled on the external cytomembrane, show a regular distribution at the top of each fold. The membrane-associated structures are discussed with regard to the gliding movement mechanism.

scholarly journals alpha 2 Macroglobulin binding to the plasma membrane of cultured fibroblasts. Diffuse binding followed by clustering in coated regions.

1979 ◽  
Vol 82 (3) ◽  
pp. 614-625 ◽  
Author(s):  
M C Willingham ◽  
F R Maxfield ◽  
I H Pastan
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Coated Vesicles ◽  
The Other ◽  
Con A ◽  
Coated Pits ◽  
Cultured Fibroblasts ◽  
Receptor Complexes ◽  
Transmission Electron ◽  
Epidermal Growth

Using transmission electron microscopy, we have studied the interaction of alpha 2 macroglobulin (alpha 2 M) with the surface of cultured fibroblasts. When cells were incubated for 2 h at 4 degrees C with ferritin-conjugated alpha 2 M, approximately 90% of the alpha 2 M was diffusely distributed on the cell surface, and the other 10% was concentrated in "coated" pits. A pattern of diffuse labeling with some clustering in "coated" pits was also obtained when cells were incubated for 5 min at 4 degrees C with alpha 2 M, fixed with glutaraldehyde, and the alpha 2 M was localized with affinity-purified, peroxidase-labeled antibody to alpha 2 M. Experiments in which cells were fixed with 0.2% paraformaldehyde before incubation with alpha 2 M showed that the native distribution of alpha 2 M receptors was entirely diffuse without significant clustering in "coated" pits. This indicates that some redistribution of the alpha 2 M-receptor complexes into clusters occurred even at 4 degrees C. In experiments with concanavalin A(Con A), we found that some of the Con A clustered in coated regions of the membrane and was internalized in coated vesicles, but much of the Con A was directly internalized in uncoated vesicles or pinosomes. We conclude that unoccupied alpha 2 M receptors are diffusely distributed on the cell surface. When alpha 2 M-receptor complexes are formed, they rapidly cluster in coated regions or pits in the plasma membrane and subsequently are internalized in coated vesicles. Because insulin and epidermal growth factor are internalized in the same structures as alpha 2 M (Maxfield, F.R., J. Schlessinger, Y. Schechter, I. Pastan, and M.C. Willingham. 1978. Cell, 14: 805--810.), we suggest that all peptide hormones, as well as other proteins that enter the cell by receptor-mediated endocytosis, follow this same pathway.

Freeze fracture studies on the interaction between the malaria parasite and the host erythrocyte inPlasmodium knowlesi infections

Parasitology ◽  
1979 ◽  
Vol 79 (1) ◽  
pp. 125-139 ◽  
Author(s):  
Diane J. McLaren ◽  
L. H. Bannister ◽  
P. I. Trigg ◽  
G. A. Butcher
Keyword(s):  
Plasma Membrane ◽  
Plasmodium Knowlesi ◽  
Parasitophorous Vacuole ◽  
Freeze Fracture ◽  
Transmembrane Proteins ◽  
Circular Particle ◽  
Erythrocyte Plasma Membrane ◽  
Characteristic Features ◽  
Integral Proteins ◽  
Development Proceeds

SUMMARYThe freeze fracture technique has been used to study the internal cyto-architecture of the surface membranes of the parasite and erythrocyte inPlasmodium knowlesiinfections. Six fracture faces, derived from the plasma membrane and 2 pellicular membranes, have been identified at the surface of the free merozoite. The apposed leaflets of the 2 pellicular membranes show the characteristic features of E fracture faces, a result compatible with the view that the pellicular membranes line a potential cisterna. There is evidence to suggest that there may be changes in the distribution and density of the integral proteins in the merozoite plasma membrane at invasion. Furthermore, vesicles consisting of stacked membranes occur within and around the erythrocyte invagination at invasion; it is suggested that these vesicles are released from the merozoite rhoptries. Formation of the parasitophorous vacuole is accompanied by dramatic changes in the density and distribution of intra-membraneous particles (IMP) in the vacuolar membrane. Initially there is a great reduction in particle numbers, but subsequently the particles reappear and show reversed polarity. The possible causes and implications of these changes are discussed. The intra-erythrocytic parasite synthesizes new transmembrane proteins as development proceeds, and the trophozoite and schizont stages of development are characterized by the appearance of circular, particle-free regions in the parasite plasmalemma. There is a decrease in the density of transmembrane proteins in the erythrocyte plasma membrane during parasite maturation, and the P face IMP show the characteristic features of aggregation.

scholarly journals Rings of membrane sterols surround the openings of vesicles and fenestrae, in capillary endothelium.

1983 ◽  
Vol 97 (5) ◽  
pp. 1592-1600 ◽  
Author(s):  
N Simionescu ◽  
F Lupu ◽  
M Simionescu
Keyword(s):  
Plasma Membrane ◽  
Cell Membrane ◽  
Cell Surface ◽  
Freeze Fracture ◽  
Short Exposure ◽  
Capillary Endothelium ◽  
Anionic Sites ◽  
Microvascular Endothelium ◽  
Coated Pits ◽  
Plasmalemmal Vesicles

We investigated the distribution of sterols in the cell membrane of microvascular endothelium (mouse pancreas, diaphragm, brain, heart, lung, kidney, thyroid, adrenal, and liver) with the polyene antibiotic filipin, which reportedly has binding specificity for free 3-beta-hydroxysterols. In some experiments, concomitantly, cell-surface anionic sites were detected with cationized ferritin. Vessels were perfused in situ with PBS, followed by light fixation and filipin administration for 10 to 60 min. Tissues were further processed for thin-section and freeze-fracture electron microscopy. Short exposure (10 min) to filipin-glutaraldehyde solution resulted in the initial appearance, on many areas, of rings of characteristic filipin-sterol complexes within the rim surrounding stomata of most plasmalemmal vesicles, transendothelial channels, and fenestrae. Such rings were absent from the rims of the large openings of the sinusoid endothelium (liver, adrenal), coated pits and phagocytic vacuoles. After longer exposure (30-60 min), filipin-sterol complexes labeled randomly the rest of plasma membrane (except for coated pits, and partially the interstrand areas of junctions), and also marked most plasmalemmal vesicles. These peristomal rings of sterols were displayed mostly on the P face, and, at their full development, consisted of 6-8 units around a vesicle stoma, and 10-12 units around a fenestra. At their level, the intramembranous particles and the cell surface anionic sites were virtually excluded. Peristomal rings of sterols were also detected on the plasma membrane of pericytes and smooth muscle cells of the microvascular wall, which otherwise were poorly labeled with filipin-sterol complexes as compared to endothelial plasmalemma. It is presumed that the peristomal rings of cholesterol may represent important contributors to the local transient stabilization of plasma membrane and to the phase separation between cell membrane and vesicle membrane at a certain stage of their fusion/fission process.

scholarly journals Surface redistribution of 125I-insulin in cultured human lymphocytes.

1981 ◽  
Vol 91 (1) ◽  
pp. 17-25 ◽  
Author(s):  
J L Carpentier ◽  
E Van Obberghen ◽  
P Gorden ◽  
L Orci
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Human Lymphocytes ◽  
Freeze Fracture ◽  
Total Cell ◽  
Coated Pits ◽  
Villous Surface ◽  
Specific Receptors ◽  
Related Proteins ◽  
Preferential Association

The cultured human lymphocyte (IM-9) binds 125I-insulin by a receptor-mediated process; the receptor, in turn, is regulated by the ligand. In the present study we have examined quantitatively the morphologic events involved in 125I-insulin interaction with the surface of the lymphocyte. At 2 min of incubation of 15 degrees or 37 degrees C, the ligand localizes preferentially at the villous surface of the cell, whereas with longer periods of incubation, the ligand distributes indistinguishably between the villous and nonvillous surface. When rebinding is blocked, 125I-insulin localizes preferentially at the nonvillous surface of the cell. When the total cell surface is considered, there is little preferential association with coated pits; when only the nonvillous surface is considered, a preferential association with coated pits is found and is quantitatively increased in the absence of rebinding of the ligand. This cell has an abundant villous surface (approximately 55% of the total surface); and, as seen on freeze-fracture replicas, the plasma membrane of the villous surface contains a 60% greater density of intramembrane particles than the nonvillous surface. The data suggest an ordered pattern of insulin interaction with the cell surface (i.e., binding to villi followed by redistribution to the nonvillous portion of the cell containing coated pits). These events probably reflect the mechanism by which the cell segregates specific receptors and related proteins in the plane of the membrane so that they can be selectively removed.

Rectilinear particle arrays in freeze-fracture replicas of the surface membrane of Paramecium tetraurelia

1986 ◽  
Vol 83 (1) ◽  
pp. 269-291
Author(s):  
R.R. Preston ◽  
T.M. Newman
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Surface Membrane ◽  
Freeze Fracture ◽  
Dorsal Surface ◽  
Surface Coat ◽  
Paramecium Tetraurelia ◽  
Intramembranous Particle ◽  
Logarithmic Growth Phase ◽  
Culture Cycle

Freeze-fracture replicas of the plasma membrane of unfixed, uncryoprotected Paramecium tetraurelia bear large rectilinear arrays of 11 nm particles arranged in 7–11 parallel rows. The arrays are of sufficient size to leave impressions in replicas of the underlying outer alveolar membrane, and are apparent as parallel ridges in replicas of the surface coat of deep-etched cells. By noting the location of arrays in replicas of identified portions of the cortex of P. tetraurelia, it has been possible to map the distribution of arrays over the cell surface. The arrays are found primarily over the anterior surfaces of the cell, covering an area that extends from the preoral suture over the left adoral field and a large portion of the anterior dorsal surface. Freeze-fracture analyses of cells taken from a number of different stages of a culture cycle suggest that the particle arrays are not replicated as an integral part of the cortex during cell division, but are assembled and oriented in the membrane as the cells mature. The appearance of small intramembranous particle complexes in the plasma membrane of cells in logarithmic growth phase supports this hypothesis, possibly representing an assembly stage in the formation of the larger particle arrays. The facts that the particle arrays are apparent in replicas of the surface coat of cells, are found primarily at the anterior of the cell body, and have a highly specific orientation with respect to the cell surface, strongly suggest that they function as chemoreceptors in P. tetraurelia.

scholarly journals Ultrastructure and cytochemistry of the mature spermatozoon of Khawia armeniaca (Cholodkovsky, 1915) (Caryophyllidea: Lytocestidae), a parasite of Capoeta capoeta sevangi (De Filippi, 1865) (Teleostei, Cyprinidae)

2020 ◽  
Vol 57 (4) ◽  
pp. 353-360
Author(s):  
M. Matoušková ◽  
M. Bruňanská ◽  
J. Nebesářová ◽  
L. G. Poddubnaya
Keyword(s):  
Anterior Part ◽  
Male Gamete ◽  
Longitudinal Axis ◽  
Mature Spermatozoon ◽  
Ultrastructural Organization ◽  
Cortical Microtubules ◽  
Transmission Electron ◽  
Cytochemical Technique ◽  
First Time ◽  
Region Ii

SummaryThe mature spermatozoon of Khawia armeniaca, a monozoic caryophyllidean parasite of templar fish Capoeta capoeta sevangi (De Filippi, 1865) from the Lake Sevan, Armenia, has been studied using transmission electron microscopy and cytochemical technique of Thiéry (1967) for the first time. The mature spermatozoon of K. armeniaca consists of a single axoneme with the 9+‘1’ trepaxonematan structure, cortical microtubules and nucleus which are situated parallel to the longitudinal axis of the spermatozoon, and a moderately electrondense cytoplasm with glycogen particles. The cortical microtubules are arranged in one continuous semicircle beneath the plasma membrane in Region II and anterior part of Region III of the mature spermatozoon. The two opposite rows of cortical microtubules are observed in the remaining nuclear and at the beginning of the postnuclear part (Regions III, IV) of the male gamete The number of cortical microtubules is remarkably variable in the spermatozoa of various Khawia species. K. armeniaca exhibits the highest number of cortical microtubules in comparison with K. sinensis and K. rossittensis. Glycogen was detected in the cytoplasm of prenuclear (II), nuclear (III) and postnuclear (IV) regions with different ultrastructural organization of the mature spermatozoon of K. armeniaca. Variations of sperm ultrastructural characters within caryophyllideans and other cestodes are discussed.

scholarly journals Rhodopsins build up the birefringent bodies of the dinoflagellate Oxyrrhis marina

PROTOPLASMA ◽  
2021 ◽  
Author(s):  
Erhard Rhiel ◽  
Christian Hoischen ◽  
Martin Westermann
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Freeze Fracture ◽  
Longitudinal Axis ◽  
Amino Acid Sequences ◽  
Fast Fourier Transformation ◽  
Oxyrrhis Marina ◽  
Transmission Electron ◽  
Food Vacuoles ◽  
Size And Morphology

AbstractThe ultrastructure of the birefringent bodies of the dinoflagellate Oxyrrhis marina was investigated by transmission electron microscopy. Ultrathin sectioning revealed that the bodies consist of highly ordered and densely packed lamellae, which show a regular striation along their longitudinal axis. A lattice distance of 6.1 nm was measured for the densely packed lamellae by FFT (Fast Fourier Transformation) analysis. In addition, a rather faint and oblique running striation was registered. Lamellae sectioned rather oblique or almost close to the surface show a honeycombed structure with a periodicity of 7.2–7.8 nm. Freeze-fracture transmission electron microscopy revealed that the lamellae are composed of highly ordered, crystalline arrays of particles. Here, FFT analysis resulted in lattice distances of 7.0–7.6 nm. Freeze-fracture transmission electron microscopy further revealed that the bodies remained intact after cell rupture followed by ascending flotation of the membrane fractions on discontinuous sucrose gradients. The birefringent bodies most likely are formed by evaginations of membranes, which separate the cytoplasm from the food vacuoles. Distinct, slightly reddish-colored areas, which resembled the birefringent bodies with respect to size and morphology, were registered by bright field light microscopy within Oxyrrhis marina cells. An absorbance maximum at 540 nm was registered for these areas, indicating that they are composed of rhodopsins. This was finally proven by immuno-transmission electron microscopy, as antisera directed against the C-terminal amino acid sequences of the rhodopsins AEA49880 and ADY17806 intensely immunolabeled the birefringent bodies of Oxyrrhis marina.

Formation of two microtubule-nucleating sites which perform differently during centrosomal reorganization in a mouse cochlear epithelial cell

1995 ◽  
Vol 108 (4) ◽  
pp. 1333-1345 ◽  
Author(s):  
J.B. Tucker ◽  
M.M. Mogensen ◽  
C.C. Paton ◽  
J.B. Mackie ◽  
C.G. Henderson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Apical Cell ◽  
Organ Of Corti ◽  
Longitudinal Axis ◽  
Sequence Of Events ◽  
Pericentriolar Material ◽  
High Concentrations ◽  
Oriented Parallel ◽  
A Site

This report provides evidence for the formation of a cell surface-associated centrosome with two spatially discrete microtubule-nucleating sites that perform differently; the minus ends of microtubules remain anchored to one site but escape from the other. Centrosomal reorganization in the cells in question, outer pillar cells of the organ of Corti, indicates that its pericentriolar material becomes intimately associated with the plasma membrane at the two nucleating sites. Two large microtubules bundles assemble in each cell. A beam which includes about 1,300 microtubules spans most of the cell apex. It is positioned at right angles to a pillar with about 4,500 microtubules which is oriented parallel to the cell's longitudinal axis. The beam's microtubules elongate from, and remain attached to, a centrosomal region with two centrioles which acts as a microtubule-nucleating site. However, the elongating microtubules do not radiate from the immediate vicinity of the centrioles. During beam assembly, the minus ends of the microtubules are concentrated together close to the plasma membrane (less than 0.2 micron away in many cases) at a site which is located to one side of the cell apex. High concentrations of the pillar's microtubules elongating from one particular site have not been detected. Analyses of pillar assembly indicate that the following sequence of events occurs. Pillar microtubules elongate from an apical cell surface-associated nucleating site, which becomes more distantly separated from the centriolar locality as cell morphogenesis progresses. Microtubules do not accumulate at this apical nucleating site because they escape from it. They migrate down to lower levels in the cell where the mature bundle is finally situated and their plus ends are captured at the cell base.

scholarly journals Label-fracture of plasma membranes isolated from measles virus-infected cells.

1993 ◽  
Vol 41 (7) ◽  
pp. 1085-1091 ◽  
Author(s):  
G Rutter ◽  
H Hohenberg
Keyword(s):  
Cell Surface ◽  
Measles Virus ◽  
Plasma Membranes ◽  
Protein A ◽  
Freeze Fracture ◽  
Fracture Morphology ◽  
Immune Serum ◽  
Outer Cell ◽  
Membrane Surfaces ◽  
Transmission Electron

We present a method that permits correlation of the intramembrane architecture of plasma membrane fracture faces with the distribution of specific molecules at the corresponding cytoplasmic or exoplasmic membrane surfaces. HeLa cells infected with measles virus were used as a model system. Large fragments of the dorsal membrane were isolated after the virus glycoproteins were tagged at the outer cell surface with immune serum and protein A-gold markers. In a second step, different virus polypeptides at the inner cell surface were also identified by a smaller gold label. Thereafter, the isolated plasma membranes were frozen and freeze-fractured. The complementary fracture faces were shadowed with heavy metals and carbon and examined in the transmission electron microscope without cleaning of remaining biological material. Thus, the micromorphology of the replicated fracture faces and the topochemistry of virus components localized at the corresponding leaflets of the plasmalemma could be seen on the same image at high resolution. Of note is that the freeze-fracture morphology of the protoplasmic face is related to the molecular composition of the cytoplasmic surface, as revealed by antibody tagging.

Heterogeneity of Size and Distribution of Intramembrane Particles in the Plasma Membrane of Yeast

1977 ◽  
Vol 35 ◽  
pp. 596-597
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Candida Utilis ◽  
Synthetic Medium ◽  
Freeze Fracture ◽  
Translational Diffusion ◽  
Yeast Cells ◽  
Distilled Water ◽  
Intramembrane Particles ◽  
The Matrix ◽  
Water Cell

The matrix of biological membranes consists of a lipid bilayer into which proteins or protein aggregates are intercalated. Freeze-fracture techni- ques permit these proteins, perhaps in association with lipids, to be visualized in the hydrophobic regions of the membrane. Thus, numerous intramembrane particles (IMP) have been found on the fracture faces of membranes from a wide variety of cells (1-3). A recognized property of IMP is their tendency to form aggregates in response to changes in experi- mental conditions (4,5), perhaps as a result of translational diffusion through the viscous plane of the membrane. The purpose of this communica- tion is to describe the distribution and size of IMP in the plasma membrane of yeast (Candida utilis).Yeast cells (ATCC 8205) were grown in synthetic medium (6), and then harvested after 16 hours of culture, and washed twice in distilled water. Cell pellets were suspended in growth medium supplemented with 30% glycerol and incubated for 30 minutes at 0°C, centrifuged, and prepared for freeze-fracture, as described earlier (2,3).

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