scholarly journals Partial and complete detachment of neutrophils and eosinophils from schistosomula: evidence for the establishment of continuity between a fused and normal parasite membrane.

1980 ◽  
Vol 86 (1) ◽  
pp. 64-76 ◽  
Author(s):  
J P Caulfield ◽  
G Korman ◽  
A E Butterworth ◽  
M Hogan ◽  
J R David
Keyword(s):  
Schistosoma Mansoni ◽  
Thin Section ◽  
Plasma Membranes ◽  
Freeze Fracture ◽  
The Other ◽  
Edge Zone ◽  
Electron Dense Material ◽  
Host Membrane ◽  
Complete Detachment ◽  
Membrane Components

Neutrophils and eosinophils adhering to the surface of schistosomula of Schistosoma mansoni have been partially or completely detached with hypertonic sucrose or by pipetting. The sucrose-treated neutrophils are attached only in areas where there are pentalaminar fusions between the neutrophil and tegumental membranes, suggesting that these fusions attach the cells to the parasites. Pipetting breaks many of the attached cells. In thin section, the tegumental membrane underlying these cells is seen to be pentalaminar. By freeze-fracture techniques, modified attachment areas are found. The edge zone often appears as a single strand of intramembrane particles (IMPs) on the P2 face and as a groove on the E2 face. The edge zone may also have large discontinuities, in which case it no longer separates membrane faces of unequal IMP density from one another. In addition, the IMPs on the IMP-rich areas become aggregated and surrounded by craters in the membrane. These experiments suggest that the fusions may be the mechanism by which the parasite acquires some host membrane components on its surface. On the other hand, eosinophil plasma membranes are seen adhering to a layer of electron-dense material on the parasite after the cells have been disrupted by pipetting. This suggests that eosinophils adhere to the parasite surface through their discharged granule material and not by membrane fusions.

scholarly journals Human erythrocytes adhering to schistosomula of Schistosoma mansoni lyse and fail to transfer membrane components to the parasite.

1985 ◽  
Vol 101 (1) ◽  
pp. 158-166 ◽  
Author(s):  
J P Caulfield ◽  
C M Cianci
Keyword(s):  
Schistosoma Mansoni ◽  
Erythrocyte Membrane ◽  
Plasma Membranes ◽  
Freeze Fracture ◽  
Human Erythrocytes ◽  
Transmission Microscopy ◽  
Carbocyanine Dyes ◽  
Host Membrane ◽  
Membrane Components ◽  
20 Nm

We studied the adherence of human erythrocytes to larvae of the intravascular parasite Schistosoma mansoni by transmission microscopy, freeze fracture, and fluorescence techniques. In addition, we used the adherent cells to investigate the problem of host antigen acquisition. Schistosomula were cultured for from 24 to 48 h after transformation in order to clear the remnants of the cercarial glycocalyx. In some cases, the worms were preincubated with wheat germ agglutinin to promote adherence of the erythrocytes. The results were similar with and without the lectin except that more cells attached to the lectin-coated parasites. Erythrocytes adhered within a few hours and, unlike neutrophils, did not fuse with the parasite. A layer of 10-20-nm electron dense material separated the outer leaflets of the tegumental and plasma membranes. In addition, many deformed and lysed cells were seen on the parasite surface. The ability of the worm to acquire erythrocyte membrane constituents was tested with carbocyanine dyes, fluorescein covalently conjugated to glycophorin, monoclonal antibodies against B and H blood group glycolipids, and rabbit alpha-human erythrocyte IgG. In summary, glycophorin, erythrocyte proteins, and glycolipids were not transferred to the parasite membrane within 48 h. Carbocyanine dyes were rapidly transferred to the parasite with or without lectin preincubation. Thus, the dye in the worm membrane came from both adherent and nonadherent cells. These studies suggest that, in the absence of membrane fusion, the parasite may acquire some lipid molecules similar in structure to host membrane glycolipids by simple transfer through the medium but that B and H glycolipids and erythrocyte membrane proteins are not transferred from adhering cells to the worm.

Membranes in lupin root nodules. I. The role of Golgi bodies in the biogenesis of infection threads and peribacteroid membranes

1978 ◽  
Vol 30 (1) ◽  
pp. 129-149 ◽  
Author(s):  
J.G. Robertson ◽  
P. Lyttleton ◽  
S. Bullivant ◽  
G.F. Grayston
Keyword(s):  
Thin Section ◽  
Osmium Tetroxide ◽  
Plasma Membranes ◽  
Phosphotungstic Acid ◽  
Freeze Fracture ◽  
Plant Cells ◽  
Golgi Bodies ◽  
Cytoplasmic Vesicles ◽  
Infection Threads ◽  
Zinc Iodide

The process of infection of lupin nodule cells by rhizobia was examined using thin-section and freeze-fracture electron-microscopic techniques to characterize the properties of different membranes and to establish relationships between them. The membranes of the Golgi bodies and the endoplasmic reticulum stained with zinc iodide-osmium tetroxide but not with phosphotungstic acid or silver. By contrast the infection thread membranes, peribacteroid membranes, plasma membranes and membranes of cytoplasmic vesicles did not stain with zinc iodide-osmium tetroxide but stained with phosphotungstic acid and silver. The peribacteroid membranes and plasma membranes are, however, different from each other since the particle density on the E face of freeze-fracture replicas of plasma membranes was twice that on the E face of the peribacteroid membranes. An examination of the tips of the infection threads in the cytoplasm of the plant cells, showed that the rhizobia bud off from the infection threads enclosed in the infection thread membranes. The rhizobia continue to divide still surrounded by membranes of plant origin, namely the peribacteroid membranes. Cytoplasmic vesicles are observed in both thin-section and freeze-fracture preparations of nodule tissue closely associated with, and apparently produced by, Golgi bodies. Formation of the walls and membranes of the infection threads and of the peribacteroid membranes involves fusion of the cytoplasmic vesicles with these membranes. It is proposed that the process of infection of plant cells in lupin nodules involves a change in the function of the Golgi body system for the biogenesis of plant cell walls and plasma membranes to include the synthesis of the walls and membranes of the infection threads and also the peribacteroid membranes.

Fenestrated vessels in human hemangioblastoma

1974 ◽  
Vol 40 (6) ◽  
pp. 696-705 ◽  
Author(s):  
Eiichi Tani ◽  
Kimiyuki Ikeda ◽  
Susumu Kudo ◽  
Shogo Yamagata ◽  
Noboru Higashi ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Thin Section ◽  
Plasma Membranes ◽  
Freeze Fracture ◽  
Fracture Plane ◽  
Content Type ◽  
Plasmalemmal Vesicles ◽  
Fracture Edge ◽  
Fine Print

✓ The capillaries in two cerebellar hemangioblastomas were studied by thin-section and freeze-fracture techniques. Fenestrae were found in the attenuated portions of the endothelium, and plasmalemmal vesicles in the nonfenestrated portions. In freeze-fracture preparations the fenestrae of the endothelial plasma membrane were about 450 to 550 A in diameter. They appeared as holes and “necks” in clusters of about 40 to 60 per µm2. When the fracture plane passed in a stepwise fashion from the luminal plasma membrane into the contraluminal plasma membrane, the fenestrae at the fracture edge involved both plasma membranes.

Deformation of Yeast Plasma Membrane by Ethidium Bromide

1988 ◽  
Vol 46 ◽  
pp. 254-255
Author(s):  
E. Keyhani
Keyword(s):  
Plasma Membrane ◽  
Thin Section ◽  
Ethidium Bromide ◽  
Freeze Fracture ◽  
Mutagenic Effect ◽  
Yeast Cells ◽  
Hydrophobic Region ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Deep Pits

The mutagenic effect of ethidium bromide on the mitochondrial DNA is well established. Using thin section electron microscopy, it was shown that when yeast cells were grown in the presence of ethidium bromide, besides alterations in the mitochondria, the plasma membrane also showed alterations consisting of 75 to 110 nm-deep pits. Furthermore, ethidium bromide induced an increase in the length and number of endoplasmic reticulum and in the number of intracytoplasmic vesicles.Freeze-fracture, by splitting the hydrophobic region of the membrane, allows the visualization of the surface view of the membrane, and consequently, any alteration induced by ethidium bromide on the membrane can be better examined by this method than by the thin section method.Yeast cells, Candida utilis. were grown in the presence of 35 μM ethidium bromide. Cells were harvested and freeze-fractured according to the procedure previously described.

scholarly journals Pancreatic plasma membranes: promiscuous partners in membrane fusion

1994 ◽  
Vol 298 (3) ◽  
pp. 599-604 ◽  
Author(s):  
E G Lee ◽  
S J Marciniak ◽  
C M MacLean ◽  
J M Edwardson
Keyword(s):  
Membrane Fusion ◽  
Plasma Membranes ◽  
Secretory Granules ◽  
The Other ◽  
Zymogen Granules ◽  
Other Hand

We have developed a system in which the fusion of pancreatic plasma membranes with zymogen granules can be studied in vitro. We show here that pancreatic plasma membranes fuse not only with pancreatic zymogen granules but also with parotid secretory granules. In contrast, parotid membranes fuse only with parotid granules and not with pancreatic granules. The extent of fusion is insensitive to Ca2+ for all combinations of plasma membranes and granules. Guanosine 5′-[gamma-thio]triphosphate (GTP[S]), on the other hand, stimulates fusion of pancreatic membranes with both pancreatic granules and parotid granules, but inhibits fusion between parotid membranes and parotid granules.

scholarly journals Pseudotypes of Vesicular Stomatitis Virus with CD4 Formed by Clustering of Membrane Microdomains during Budding

2005 ◽  
Vol 79 (11) ◽  
pp. 7077-7086 ◽  
Author(s):  
Erica L. Brown ◽  
Douglas S. Lyles
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Lipid Rafts ◽  
Immunoelectron Microscopy ◽  
Vesicular Stomatitis Virus ◽  
Plasma Membranes ◽  
Membrane Microdomains ◽  
Virus Budding ◽  
Vesicular Stomatitis ◽  
Membrane Components

ABSTRACT Many plasma membrane components are organized into detergent-resistant membrane microdomains referred to as lipid rafts. However, there is much less information about the organization of membrane components into microdomains outside of lipid rafts. Furthermore, there are few approaches to determine whether different membrane components are colocalized in microdomains as small as lipid rafts. We have previously described a new method of determining the extent of organization of proteins into membrane microdomains by analyzing the distribution of pairwise distances between immunogold particles in immunoelectron micrographs. We used this method to analyze the microdomains involved in the incorporation of the T-cell antigen CD4 into the envelope of vesicular stomatitis virus (VSV). In cells infected with a recombinant virus that expresses CD4 from the viral genome, both CD4 and the VSV envelope glycoprotein (G protein) were found in detergent-soluble (nonraft) membrane fractions. However, analysis of the distribution of CD4 and G protein in plasma membranes by immunoelectron microscopy showed that both were organized into membrane microdomains of similar sizes, approximately 100 to 150 nm. In regions of plasma membrane outside of virus budding sites, CD4 and G protein were present in separate membrane microdomains, as shown by double-label immunoelectron microscopy data. However, virus budding occurred from membrane microdomains that contained both G protein and CD4, and extended to approximately 300 nm, indicating that VSV pseudotype formation with CD4 occurs by clustering of G protein- and CD4-containing microdomains.

Transmembrane phospholipid distribution revealed by freeze-fracture replica labeling

1996 ◽  
Vol 109 (10) ◽  
pp. 2453-2460 ◽  
Author(s):  
K. Fujimoto ◽  
M. Umeda ◽  
T. Fujimoto
Keyword(s):  
Plasma Membranes ◽  
Membrane Lipids ◽  
Secretory Granules ◽  
General Scheme ◽  
Sodium Dodecyl ◽  
Freeze Fracture ◽  
Electron Microscopic Observation ◽  
Erythrocyte Membranes ◽  
Electron Microscopic ◽  
Intracellular Membranes

We propose the use of membrane splitting by freeze-fracture for differential phospholipid analysis of protoplasmic and exoplasmic membrane leaflets (halves). Unfixed cells or tissues are quick-frozen, freeze-fractured, and platinum-carbon (Pt/C) shadowed. The Pt/C replicas are then treated with 2.5% sodium dodecyl sulfate (SDS) to solubilize unfractured membranes and to release cytoplasm or contents. While the detergent dissolves unfractured membranes, it would not extract lipids from split membranes, as their apolar domains are stabilized by their Pt/C replicas. After washing, the Pt/C replicas, along with attached protoplasmic and exoplasmic membrane halves, are processed for immunocytochemical labeling of phospholipids with antibody, followed by electron microscopic observation. Here, we present the application of the SDS-digested freeze-fracture replica labeling (SDS-FRL) technique to the transmembrane distribution of a major membrane phospholipid, phosphatidylcholine (PC), in various cell and intracellular membranes. Immunogold labeling revealed that PC is exclusively localized on the exoplasmic membrane halves of the plasma membranes, and the intracellular membranes of various organelles, e.g. nuclei, mitochondria, endoplasmic reticulum, secretory granules, and disc membranes of photoreceptor cells. One exception to this general scheme was the plasma membrane forming the myelin sheath of neurons and the Ca(2+)-treated erythrocyte membranes. In these cell membranes, roughly equal amounts of immunogold particles for PC were seen on each outer and inner membrane half, implying a symmetrical transmembrane distribution of PC. Initial screening suggests that the SDS-FRL technique allows in situ analysis of the transmembrane distribution of membrane lipids, and at the same time opens up the possibility of labeling membranes such as intracellular membranes not normally accessible to cytochemical labels without the distortion potentially associated with membrane isolation procedures.

Membrane changes associated with mucus production by intestinal goblet cells

1978 ◽  
Vol 33 (1) ◽  
pp. 301-316
Author(s):  
J.G. Swift ◽  
T.M. Mukherjee
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Membrane Fusion ◽  
Thin Section ◽  
Structural Organization ◽  
Freeze Fracture ◽  
Goblet Cells ◽  
Mucus Production ◽  
Membrane Reorganization ◽  
Membrane Changes

Changes in the structural organization of membranes of mucous bodies and the plasma membrane that occur during mucus production in goblet cells of rat rectum have been studied by thin-section and freeze-fracture techniques. Immature mucous bodies are bounded by a trilaminar membrane and fracture faces of the membrane have randomly distributed intramembrane particles. During maturation, mucous bodies become packed tightly together and changes in the structure of their membranes include (1) fusion of apposing membranes of adjacent bodies to form a pentalaminar structure, (2) a reduction in the density of particles on membrane fracture faces, and (3) exclusion of particles from regions of membrane apposition. Some trilaminar membranes of mucous bodies fuse with the lumenal plasma membrane to form a pentalaminar structure. Sites of apposition between mucous body membranes and the lumenal plasma membrane are seen as particle-cleared bulges on fracture faces of the plasma membrane. Our results indicate that membrane reorganization associated with mucous production in goblet cells includes a reduction and redistribution of some membrane proteins and that membrane fusion occurs between portions of membranes from which proteins have been displaced.

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