High concentration of plasma membrane H+-ATPase in root caps ofLepidium sativum L.

1993 ◽  
Vol 80 (7) ◽  
pp. 317-319 ◽  
Author(s):  
H. -G. Stenz ◽  
H. -G. Heumann ◽  
M. H. Weisenseel
Keyword(s):  
Plasma Membrane ◽  
High Concentration

Endothelial Alterations During The Platelet Activating Factor (PAF) Respiratory Distress Syndrome

1981 ◽  
Author(s):  
J C Lewis ◽  
J T O’Flaherty ◽  
C M McCall ◽  
R L Wykle
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Platelet Activating Factor ◽  
Capillary Endothelium ◽  
Cytotoxic Action ◽  
High Concentration ◽  
Rabbit Lung ◽  
Capillary Endothelial Cells ◽  
Platelet Aggregates

PAF (l-0-alkyl-2-0-acetyl-sn-gylcero-3-phosphocholine) induces polymorphonucelar leukocyte and platelet stasis in rabbit lung capillaries in vitro and produces a model of acute respiratory disease. Since PAF mediates anaphylactic reactions, a study was done to determine the ultrastructural effects of PAF treatment. Mature rabbits were treated by intravenous administration of either PAF (0.15-10 μg/kg: 8 animals) or BSA (the PAF carrier: 3 animals) prior to sacrifice and intraventricular perfusion with 0.1 M phosphate buffered (pH 7.2) glutaraldehyde (2.5%). Animals (n=5) injected with a high concentration of PAF (3-10 μg/kg) and sacrificed within 15 minutes of PAF administration had grossly contracted lungs, the vasculature of which (as observed by scanning electron microscopy) contained numerous marginated leukocytes and platelet aggregates. Animals (n=3) given PAF in the concentration range 0.15-2.4 μg/kg had less consistent lung contraction and fewer platelet aggregates within capillaries. Luminal surfaces of capillary endothelial cells in all PAF treated animals (when observed by transmission electron microscopy [TEM]) were dramatically altered. In contrast to the uniformly smooth surfaces in control animals, vessels in the PAF treated animals had tortuous surfaces with plasma membrane discontinuities and protrusion of plasma membrane fragments into the capillary lumen. Morphometric analysis of TEM micrographs substantiated statistically significant (p<0.01) increases in the number and size of plasmalemmal vesicles.These observations clearly document a cytotoxic effect for capillary endothelium. This cytotoxic action may in part explain the clinical effect of PAF.

scholarly journals THE SELECTIVE INHIBITION OF MACROPHAGE PHAGOCYTIC RECEPTORS BY ANTI-MEMBRANE ANTIBODIES

1972 ◽  
Vol 135 (3) ◽  
pp. 458-475 ◽  
Author(s):  
Phillip Holland ◽  
Nancy H Holland ◽  
Zanvil A. Cohn
Keyword(s):  
Plasma Membrane ◽  
Selective Inhibition ◽  
Morphological Evidence ◽  
Igg Antibodies ◽  
High Concentration ◽  
Mouse Macrophages ◽  
Γ Globulins ◽  
Membrane Attachment ◽  
Common Antigens ◽  
Partial Blockade

Rabbit antibodies were prepared against purified mouse macrophages, erythrocytes, and liver lysosomes. In the presence of complement each of these reagents was capable of lysing mouse erythrocytes and macrophages. In the absence of complement, all antisera agglutinated mouse erythrocytes and at high concentration produced a cytotoxic effect on macrophages. At IgG concentrations of 100 µg/ml, no morphological evidence of cytotoxicity was evident. These data suggest the presence of common antigens on the erythrocyte and macrophage plasma membrane. Anti-macrophage, anti-erythrocyte, and anti-lysosomal γ-globulins and IgG, employed at subtoxic concentrations, all inhibited the attachment and ingestion of opsonized erythrocytes and mycoplasma. This occurred without significant reduction in the phagocytosis of polystyrene particles, formalinized erythrocytes, and yeast cell walls. Each of the anti-membrane IgG antibodies was capable of blocking the Fc receptor on the macrophage plasma membrane. Attachment to the macrophage membrane occurred by means of the Fab region. However, a role for the Fc portion of the molecule was suggested since pepsin-digested IgG was unable to block the receptor. Each of the IgG antibodies produced a partial blockade of the complement receptor and reduced the ingestion of EAC1,4,2,3 by approximately 50%.

scholarly journals ELECTRIC IMPEDANCE OF ASTERIAS EGGS

1936 ◽  
Vol 19 (4) ◽  
pp. 609-623 ◽  
Author(s):  
Kenneth S. Cole ◽  
Robert H. Cole
Keyword(s):  
Plasma Membrane ◽  
Sea Water ◽  
Specific Resistance ◽  
Surface Conductance ◽  
Electric Impedance ◽  
High Concentration ◽  
Low Frequencies ◽  
Definite Evidence ◽  
Asterias Forbesi ◽  
Current Resistance

The alternating current resistance and capacity of suspensions of unfertilized eggs of Asterias forbesi have been measured at frequencies from one thousand to sixteen million cycles per second. The plasma membrane of the egg has a static capacity of 1.10µf/cm.2 which is practically independent of frequency. The suspensions show a capacity dependent on frequency at low frequencies which may be attributable to surface conductance. The specific resistance of the cytoplasm is between 136 and 225 ohm cm. (4 to 7 times sea water), indicating a relatively high concentration of non-electrolytes. At frequencies above one million cycles there is definite evidence of another element of which the nucleus is presumably a part.

scholarly journals The influence of basal lamina on the accumulation of acetylcholine receptors at synaptic sites in regenerating muscle.

1984 ◽  
Vol 98 (4) ◽  
pp. 1453-1473 ◽  
Author(s):  
U J McMahan ◽  
C R Slater
Keyword(s):  
Plasma Membrane ◽  
Basal Lamina ◽  
Muscle Fiber ◽  
Acetylcholine Receptors ◽  
Skeletal Muscles ◽  
Neuromuscular Junctions ◽  
High Concentration ◽  
Direct Role ◽  
Synaptic Region ◽  
Membrane Infoldings

If skeletal muscles are damaged in ways that spare the basal lamina sheaths of the muscle fibers, new myofibers develop within the sheaths and neuromuscular junctions form at the original synaptic sites on them. At the regenerated neuromuscular junctions, as at the original ones, the muscle fiber plasma membrane is characterized by infoldings and a high concentration of acetylcholine receptors (AChRs). The aim of this study was to determine whether or not the synaptic portion of the myofiber basal lamina sheath plays a direct role in the formation of the subsynaptic apparatus on regenerating myofibers, a question raised by the results of earlier experiments. The junctional region of the frog cutaneous pectoris muscle was crushed or frozen, which resulted in disintegration and phagocytosis of all cells at the synapse but left intact much of the myofiber basal lamina. Reinnervation was prevented. When new myofibers developed within the basal lamina sheaths, patches of AChRs and infoldings formed preferentially at sites where the myofiber membrane was apposed to the synaptic region of the sheaths. Processes from unidentified cells gradually came to lie on the presynaptic side of the basal lamina at a small fraction of the synaptic sites, but there was no discernible correlation between their presence and the effectiveness of synaptic sites in accumulating AChRs. We therefore conclude that molecules stably attached to the myofiber basal lamina at synaptic sites direct the formation of subsynaptic apparatus in regenerating myofibers. An analysis of the distribution of AChR clusters at synaptic sites indicated that they formed as a result of myofiber-basal lamina interactions that occurred at numerous places along the synaptic basal lamina, that their presence was not dependent on the formation of plasma membrane infoldings, and that the concentration of receptors within clusters could be as great as the AChR concentration at normal neuromuscular junctions.

scholarly journals tpo3 and dur3, Aspergillus fumigatus Plasma Membrane Regulators of Polyamines, Regulate Polyamine Homeostasis and Susceptibility to Itraconazole

2020 ◽  
Vol 11 ◽  
Author(s):  
Mingcong Chen ◽  
Guowei Zhong ◽  
Sha Wang ◽  
Jun Zhu ◽  
Lei Tang ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Plasma Membrane ◽  
Aspergillus Fumigatus ◽  
Drug Transport ◽  
Opportunistic Pathogen ◽  
Moderate Increase ◽  
High Concentration ◽  
Polyamine Biosynthesis ◽  
Drastic Increase ◽  
Polyamine Content

Aspergillus fumigatus is a well-known opportunistic pathogen that causes invasive aspergillosis (IA) infections, which have high mortality rates in immunosuppressed individuals. Long-term antifungal drug azole use in clinical treatment and agriculture results in loss of efficacy or drug resistance. Drug resistance is related to cellular metabolites and the corresponding gene transcription. In this study, through untargeted metabolomics and transcriptomics under itraconazole (ITC) treatment, we identified two plasma membrane-localized polyamine regulators tpo3 and dur3, which were important for polyamine homeostasis and susceptibility to ITC in A. fumigatus. In the absence of tpo3 and/or dur3, the levels of cytoplasmic polyamines had a moderate increase, which enhanced the tolerance of A. fumigatus to ITC. In comparison, overexpression of tpo3 or dur3 induced a drastic increase in polyamines, which increased the sensitivity of A. fumigatus to ITC. Further analysis revealed that polyamines concentration-dependently affected the susceptibility of A. fumigatus to ITC by scavenging reactive oxygen species (ROS) at a moderate concentration and promoting the production of ROS at a high concentration rather than regulating drug transport. Moreover, inhibition of polyamine biosynthesis reduced the intracellular polyamine content, resulted in accumulation of ROS and enhanced the antifungal activity of ITC. Interestingly, A. fumigatus produces much lower levels of ROS under voriconazole (VOC) treatment than under ITC-treatment. Accordingly, our study established the link among the polyamine regulators tpo3 and dur3, polyamine homeostasis, ROS content, and ITC susceptibility in A. fumigatus.

scholarly journals The inositol 1,4,5,-trisphosphate receptor in cerebellar Purkinje cells: quantitative immunogold labeling reveals concentration in an ER subcompartment.

1990 ◽  
Vol 111 (2) ◽  
pp. 615-624 ◽  
Author(s):  
T Satoh ◽  
C A Ross ◽  
A Villa ◽  
S Supattapone ◽  
T Pozzan ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Purkinje Cells ◽  
Average Density ◽  
High Concentration ◽  
Inositol 1,4,5 Trisphosphate ◽  
Cerebellar Tissue ◽  
Specific Receptors ◽  
Membrane Bound ◽  
Cerebellar Purkinje Cells ◽  
Trisphosphate Receptor

The Ca2+ mobilization effect of inositol 1,4,5-trisphosphate, the second messenger generated via receptor-stimulated hydrolysis of phosphatidylinositol 4,5-bisphosphate, is mediated by binding to intracellular receptors, which are expressed in high concentration in cerebellar Purkinje cells. Partially conflicting previous reports localized the receptor to various subcellular structures: elements of ER, both rough and smooth-surfaced, the nuclear envelope, and even the plasma membrane. We have now reinvestigated the problem quantitatively by using cryosections of rat cerebellar tissue immunolabeled with polyclonal monospecific antibodies against the inositol 1,4,5-trisphosphate receptor. By immunofluorescence the receptor was detected only in Purkinje cells, whereas the other cells of the cerebellar cortex remained negative. In immunogold-decorated ultrathin cryosections of the Purkinje cell body, the receptor was concentrated in cisternal stacks (piles of up to 12 parallel cisternae separated by regularly spaced bridges, located both in the deep cytoplasm and beneath the plasma membrane; average density, greater than 5 particles/micron of membrane profile); in cisternal singlets and doublets adjacent to the plasma membrane (average density, approximately 2.5 particles/micron); and in other apparently smooth-surfaced vesicular and tubular profiles. Additional smooth-surfaced elements were unlabeled. Perinuclear and rough-surfaced ER cisternae were labeled much less by themselves (approximately 0.5 particles/micron, two- to threefold the background), but were often in direct membrane continuity with heavily labeled, smooth-surfaced tubules and cisternal stacks. Finally, mitochondria, Golgi cisternae, multivesicular bodies, and the plasma membrane were unlabeled. In dendrites, approximately half of the nonmitochondrial, membrane-bound structures (cisternae, tubules, and vesicles), as well as small cisternal stacks, were labeled. Dendritic spines always contained immunolabeled cisternae and vesicles. The dendritic plasma membrane, of both shaft and spines, was consistently unlabeled. These results identify a large, smooth-surfaced ER subcompartment that appears equipped to play a key role in the control of Ca2+ homeostasis: in particular, in the generation of [Ca2+]i transients triggered by activation of specific receptors, such as the quisqualate-preferring trans(+/-)-1-amino-1,3-cyclopentamedicarboxylic acid glutamatergic receptors, which are largely expressed by Purkinje cells.

scholarly journals On the mechanism of rapid plasma membrane and chloroplast envelope expansion in Dunaliella salina exposed to hypoosmotic shock.

1986 ◽  
Vol 102 (1) ◽  
pp. 289-297 ◽  
Author(s):  
M Maeda ◽  
G A Thompson
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Thin Section ◽  
Dunaliella Salina ◽  
Membrane Surface ◽  
Freeze Fracture ◽  
Chloroplast Envelope ◽  
Outer Envelope ◽  
High Concentration ◽  
Selective Fusion

Dunaliella salina cells rapidly diluted from their normal 1.71 M NaCl-containing growth medium into medium containing 0.86 M NaCl swelled within 2--4 min to an average volume 1.76 X larger and a surface area 1.53 X larger than found in control cells. Morphometric analysis of thin section electron micrographs revealed that certain organelles, including the chloroplast, nucleus, and some types of vacuoles, also expanded in surface area as much or more than did the entire cell. It is likely that glycerol, the most important osmotically active intracellular solute, was present in high concentration within these organelles as well as in the cytoplasm itself. Thin section and freeze-fracture electron microscopy were utilized to trace the origin of membrane material whose addition permitted the large increase in plasma membrane surface area and the equally large growth of the chloroplast outer envelope. The findings indicated that the plasma membrane's expansion resulted from its selective fusion with numerous small (less than or equal to 0.25 micron diam) vesicles prevalent throughout the cytoplasm. In contrast, new membrane added to the chloroplast outer envelope was drawn from an entirely different source, namely, elements of the endoplasmic reticulum.

scholarly journals Different Types of nsP3-Containing Protein Complexes in Sindbis Virus-Infected Cells

2008 ◽  
Vol 82 (20) ◽  
pp. 10088-10101 ◽  
Author(s):  
Rodion Gorchakov ◽  
Natalia Garmashova ◽  
Elena Frolova ◽  
Ilya Frolov
Keyword(s):  
Plasma Membrane ◽  
Mammalian Cells ◽  
Sindbis Virus ◽  
Protein Complexes ◽  
Nonstructural Proteins ◽  
Cell Nuclei ◽  
High Concentration ◽  
Mosquito Cells ◽  
Infected Cells ◽  
Rna Complexes

ABSTRACT Alphaviruses represent a serious public health threat and cause a wide variety of diseases, ranging from severe encephalitis, which can result in death or neurological sequelae, to mild infection, characterized by fever, skin rashes, and arthritis. In the infected cells, alphaviruses express only four nonstructural proteins, which function in the synthesis of virus-specific RNAs and in modification of the intracellular environment. The results of our study suggest that Sindbis virus (SINV) infection in BHK-21 cells leads to the formation of at least two types of nsP3-containing complexes, one of which was found in association with the plasma membrane and endosome-like vesicles, while the second was coisolated with cell nuclei. The latter complexes could be solubilized only with the cytoskeleton-destabilizing detergent. Besides viral nsPs, in the mammalian cells, both complexes contained G3BP1 and G3BP2 (which were found in different ratios), YBX1, and HSC70. Rasputin, an insect cell-specific homolog of G3BP1, was found in the nsP3-containing complexes isolated from mosquito cells, which was suggestive of a high conservation of the complexes in the cells of both vertebrate and invertebrate origin. The endosome- and plasma membrane-associated complexes contained a high concentration of double-stranded RNAs (dsRNAs), which is indicative of their function in viral-RNA synthesis. The dsRNA synthesis is likely to efficiently proceed on the plasma membrane, and at least some of the protein-RNA complexes would then be transported into the cytosol in association with the endosome-like vesicular organelles. These findings provide new insight into the mechanism of SINV replication and virus-host cell interactions.

High Concentration of Ketone Body β-Hydroxybutyrate Modifies Synaptic Vesicle Cycle and Depolarizes Plasma Membrane of Rat Brain Synaptosomes

2019 ◽  
Vol 70 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Polina P. Voronina ◽  
Ksenia V. Adamovich ◽  
Tatyana V. Adamovich ◽  
Tatsiana G. Dubouskaya ◽  
Sviatlana V. Hrynevich ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Rat Brain ◽  
Synaptic Vesicle ◽  
Ketone Body ◽  
High Concentration ◽  
Rat Brain Synaptosomes ◽  
Brain Synaptosomes ◽  
Vesicle Cycle ◽  
Synaptic Vesicle Cycle

scholarly journals Interactions of the Lysosomotropic Detergent O-Methyl-Serine Dodecylamide Hydrochloride (MSDH) with Lipid Bilayer Membranes—Implications for Cell Toxicity

2020 ◽  
Vol 21 (9) ◽  
pp. 3136 ◽  
Author(s):  
Ana-Maria Villamil Giraldo ◽  
Ida Eriksson ◽  
Stefan Wennmalm ◽  
Timmy Fyrner ◽  
Thomas Ederth ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Lipids ◽  
Apoptotic Cell ◽  
Human Fibroblasts ◽  
Membrane Integrity ◽  
Chemical Properties ◽  
High Ratio ◽  
Lipid Bilayer Membranes ◽  
High Concentration ◽  
Liposome Membrane

O-methyl-serine dodecylamine hydrochloride (MSDH) is a detergent that accumulates selectively in lysosomes, a so-called lysosomotropic detergent, with unexpected chemical properties. At physiological pH, it spontaneously forms vesicles, which disassemble into small aggregates (probably micelles) below pH 6.4. In this study, we characterize the interaction between MSDH and liposomes at different pH and correlate the findings to toxicity in human fibroblasts. We find that the effect of MSDH on lipid membranes is highly pH-dependent. At neutral pH, the partitioning of MSDH into the liposome membrane is immediate and causes the leakage of small fluorophores, unless the ratio between MSDH and lipids is kept low. At pH 5, the partitioning of MSDH into the membrane is kinetically impeded since MSDH is charged and a high ratio between MSDH and the lipids is required to permeabilize the membrane. When transferred to cell culture conditions, the ratio between MSDH and plasma membrane lipids must therefore be low, at physiological pH, to maintain plasma membrane integrity. Transmission electron microscopy suggests that MSDH vesicles are taken up by endocytosis. As the pH of the endosomal compartment progressively drops, MSDH vesicles disassemble, leading to a high concentration of increasingly charged MSDH in small aggregates inside the lysosomes. At sufficiently high MSDH concentrations, the lysosome is permeabilized, the proteolytic content released to the cytosol and apoptotic cell death is induced.

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