scholarly journals Morphometric and cytochemical studies of Dictyostelium discoideum in vegetative phase. Digestive system and membrane turnover.

1977 ◽  
Vol 75 (1) ◽  
pp. 200-217 ◽  
Author(s):  
A Ryter ◽  
C de Chastellier
Keyword(s):  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Cell Membrane ◽  
Cell Surface ◽  
Surface Area ◽  
Digestive System ◽  
Culture Medium ◽  
Axenic Medium ◽  
Membrane Turnover ◽  
Cytochemical Demonstration

The morphometric analysis of growing cells shows that the membranes of the digestive apparatus have a surface area equal to the cell surface area. After yeast phagocytosis, the surface area of the membrane surrounding the ingested yeast is equal to 40% of the surface area of the cell membrane. In spite of this internalization, the cell surface remains constant. Its renewal is insured by the translocation of the membrane of the digestive system, the surface area that concomitantly decreases by 40%. This means that the influx of plasma membrane is continually compensated for by the same outflow of internal membranes. During this turnover, the characteristic polysaccharide stainability (two different stains were used) of the plasma membrane is maintained after internalization, at the level of the digestive system, despite the presence of hydrolases in the digestive vacuoles. The cytochemical demonstration of acid phosphatase shows that this enzyme penetrates into phagosomes by fusion between phagosomes and vacloles of various sizes. The debris of digested yeast are released into the culture medium after 2 h. This process of defecation is accompanied by the appearance of new pinocytotic vacuoles, which indicates that the uptake of axenic medium has resumed. A model of membrane turnover is proposed to explain these observations.

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 Ultrastructural visualization of selective peanut agglutinin binding sites in rat osteoclasts.

1988 ◽  
Vol 36 (1) ◽  
pp. 95-101 ◽  
Author(s):  
M Takagi ◽  
H Yagasaki ◽  
T Baba ◽  
H Baba
Keyword(s):  
Plasma Membrane ◽  
Cell Membrane ◽  
Cell Surface ◽  
Binding Sites ◽  
Peanut Agglutinin ◽  
Coated Pits ◽  
Cytoplasmic Surface ◽  
Coated Membranes ◽  
Entire Cell ◽  
Ruffled Border

We investigated the distribution of concanavalin A (ConA)-reactive alpha-D-mannosyl and alpha-D-glucosyl groups and peanut agglutinin (PNA)-reactive beta-D-galactose-(1----3)-N-acetyl-D-galactosamine residues on the surface of osteoclasts with pre-embedment ultrastructural lectin cytochemistry after aldehyde fixation of the metaphyses of the rat tibiae. By routine morphology, the plasma membrane of the ruffled border of the osteoclast was distinguished from the rest of the cell membrane, with the exception of the membrane of coated pits, by its characteristic thick coat at its cytoplasmic surface. Cytochemistry, using ConA in combination with horseradish peroxidase (ConA-HRP) and PNA conjugated to HRP, showed that binding of ConA was distributed over the entire cell surface of osteoclasts. In contrast, intense binding of PNA was limited to the membranes of the ruffled border and coated pits, whereas the remainder of the cell membrane stained weakly or not at all. These results demonstrate that preferential PNA binding sites of the cell surface correspond to coated membranes associated with osteoclastic endocytosis.

A ‘Dynamic Adder Model’ For Cell Size Homeostasis in Dictyostelium Cells

2021 ◽  
Author(s):  
Masahito Tanaka ◽  
Shigehiko Yumura
Keyword(s):  
Cell Surface ◽  
Surface Area ◽  
Cell Size ◽  
Surface Membrane ◽  
Total Cell ◽  
Membrane Turnover ◽  
Cell Surface Area ◽  
Daughter Cells ◽  
A Cell ◽  
Original Size

Abstract After a cell divides into two daughter cells, the total cell surface area of the daughtercells should increase to the original size to maintain cell size homeostasis in a single cellcycle. Previously, three models have been proposed to explain the regulation of cell sizehomeostasis: sizer, timer, and adder models. Here, we precisely measured the total cellsurface area of Dictyostelium cells in a whole cell cycle by using the agar-overlaymethod, which eliminated the influence of surface membrane reservoirs, such asmicrovilli and membrane winkles. The total cell surface area linearly increased duringinterphase, slightly decreased at the metaphase, and then increased by approximately20% during cytokinesis. From the analysis of the added surface area, we concluded thatthe cell size was regulated by the near-adder model in interphase and by the timer modelin the mitotic phase. The adder model in the interphase is not caused by a simple cellmembrane addition, but is more dynamic due to the rapid cell membrane turnover. Wepropose a ‘dynamic adder model’ to explain cell size homeostasis in the interphase.

scholarly journals SYNTHESIS, INTRACELLULAR DISTRIBUTION, AND SECRETION OF IMMUNOGLOBULIN AND H-2 ANTIGEN IN MURINE SPLENOCYTES

1973 ◽  
Vol 138 (4) ◽  
pp. 847-857 ◽  
Author(s):  
Dorothee Wernet ◽  
Ellen S. Vitetta ◽  
Jonathan W. Uhr ◽  
Edward A. Boyse
Keyword(s):  
Plasma Membrane ◽  
Cell Membrane ◽  
Cell Surface ◽  
Spleen Cells ◽  
Murine Splenocytes ◽  
Peripheral Protein ◽  
Surface Areas ◽  
Membrane Bound ◽  
Cell Fractions ◽  
Fixed Cell

A/J spleen cells were labeled with [3H]leucine and at intervals thereafter were homogenized and separated into microsomes and cell sap. Ig and H-2 antigens were assayed in the cell fractions and cell supernatants using immunoprecipitation. In addition, cells labeled by enzymatic radioiodination were incubated to determine the rates of release of Ig and H-2 antigens from the surface. The results indicate that the majority of Ig and H-2 antigens remain membrane bound throughout their intracellular life. In contrast to Ig, H-2 antigens are neither secreted nor shed from the cell surface. It is suggested that Ig is a peripheral protein of the cell membrane, whereas H-2 antigens are integral ones. The release of Ig on a fragment of plasma membrane could occur at fixed cell surface areas that contain no H-2 antigens or from which they have migrated before release.

scholarly journals THE FUNCTION OF THE GOLGI COMPLEX IN TRANSITIONAL EPITHELIUM

1966 ◽  
Vol 30 (3) ◽  
pp. 623-643 ◽  
Author(s):  
R. M. Hicks
Keyword(s):  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Cell Surface ◽  
Indirect Evidence ◽  
Free Cell ◽  
Transitional Epithelium ◽  
Multivesicular Bodies ◽  
Membrane Flow ◽  
Squamous Cells ◽  
Golgi System

The superficial squamous cells of rat transitional epithelium are limited, on their luminal face, by an asymmetrically thickened membrane. Patches of similar thick membrane are found in the walls of the Golgi cisternae and it is suggested that the Golgi system is the site of assembly of the thick plasma membrane. This implies membrane flow from the Golgi apparatus to the cell surface, and there is indirect evidence that the membrane is transported in the form of fusiform vacuoles, derived from the Golgi cisternae, which fuse with, and become part of, the free cell membrane. Uptake of injected Imferon shows that similar, large, thick-walled vacuoles may be formed by invagination of the free cell surface. Some of these vacuoles are subsequently transformed into multivesicular bodies and autophagic vacuoles. The formation of other large heterogeneous bodies is described, and some of these are shown to have acid phosphatase activity.

scholarly journals Changes of the cell surface and of the digestive apparatus of dictyostelium discoideum during the starvation period triggering aggregation

1977 ◽  
Vol 75 (1) ◽  
pp. 218-236 ◽  
Author(s):  
C De Chastellier ◽  
A Ryter
Keyword(s):  
Cell Membrane ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Digestive System ◽  
Morphological Changes ◽  
Volume Ratio ◽  
Ruthenium Red ◽  
Starvation Period ◽  
Surface Areas ◽  
Phagocytic Cups

The effects of starvation on the cell morphology of Dictyostelium discoideum were studied with different cytochemical techniques, and with a morphometric method by which the surface areas of the cell membrane and of the digestive system can be determined. During the first 2 h, the cell membrane becomes very wrinkled and many phagocytic cups and filopods are formed. These changes are in accord with the 40 percent increase in the cell surface area to cytoplasmic volume ratio observed, which is mainly due to a strong decrease in the cytoplasmic volume. At this time of starvation, cells are able to ingest twice as many yeast as during growth. Afterwards, while the phagocytic ability decreases, the phagocytic cups disappear, and all the cells become bristled with many thin filopods. In spite of these morphological changes, no quantitative or topological differences have been observed concerning the polysaccharide content of the plasma membrane, whether it was stained with phosphotungstic acid, silver proteinate, or ruthenium red. During this time, the digestive vacuoles imbricate one into the other. Part of the vacuoles are degraded by this process, thus leading to an atrophy of the digestive apparatus. The digestive apparatus is progressively replaced by an autophagic system. Polysaccharide stainings and morphological observations show that the cytosegresomes seem to originate from the food vacuoles which flatten and sequester portions of cytoplasm. After 5 h of starvation, the digestive system is entirely transformed into an autophagic apparatus. The cell population appears to be homogeneous with respect to these changes. Therefore, potential precursors of prestalk and prespore cells were not observed.

Extracellularly applied ruthenium red and cADP ribose elevate cytosolic Ca2+ in isolated rat osteoclasts

1996 ◽  
Vol 270 (3) ◽  
pp. F469-F475 ◽  
Author(s):  
O. A. Adebanjo ◽  
V. S. Shankar ◽  
M. Pazianas ◽  
B. J. Simon ◽  
F. A. Lai ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Potential ◽  
Cell Membrane ◽  
Cell Surface ◽  
Divalent Cation ◽  
Ruthenium Red ◽  
The Face ◽  
A Cell ◽  
Cation Sensing ◽  
Isolated Rat

We demonstrated recently that the divalent cation-sensing receptor on the osteoclast, the Ca2+ receptor (CaR), is a functional component of a cell surface-expressed ryanodine receptor-like molecule (RyR). The objective of the present study was to further characterize this putative RyR by use of the two well-known cell-impermeant RyR modulators, ruthenium red and adenosine 3',5'-cyclic diphosphate ribose (cADPr). We found that, when applied extracellularly, ruthenium red (5 x 10(-8)-10(-4) M) and cADPr (5 x 10(-6) M) triggered an elevation of cytosolic [Ca2+]. Depolarization of the cell membrane by the application of 0.1 M K+ in the presence of 5 x 10(-6) M. valinomycin resulted in a concentration-dependent increase in the magnitude of the cytosolic Ca2+ response to extracellular ruthenium red (5 x 10(-9) and 5 x 10(-5) M), a phenomenon that was not seen when osteoclasts were hyperpolarized using 5 x 10(-3) M K+ with 5 x 10(-6) M valinomycin. In the presence of an intact nonleaky cell membrane, these results would favor a plasma membrane locus of action for the two modulators. Furthermore, pretreatment of osteoclasts with either modulator resulted in a markedly attenuated cytosolic Ca2+ transient elicited in response to the CaR agonist Ni2+, thus confirming an interaction between the cADPr- and ruthenium red-sensitive sites and the osteoclast CaR. The inhibition of the cytosolic Ca2+ response to Ni2+ induced by ruthenium red remained unchanged in the face of membrane potential changes. Finally, the cytosolic Ca2+ response to caffeine (5 x 10(-4) M), another RyR modulator, was also strongly attenuated by pretreatment with 5 x 10(-9) M ruthenium red. We conclude that ruthenium red and cADPr act on plasma membrane-resident sites and that both these sites interact with the process of divalent cation sensing.

Endocytosis and the lysosomal apparatus of rat Leydig cells

1984 ◽  
Vol 42 ◽  
pp. 708-709
Author(s):  
M.F. Lalli ◽  
L. Hermo ◽  
Y. Clermont
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Cell Surface ◽  
Leydig Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Extracellular Fluid ◽  
Multivesicular Bodies ◽  
Rat Testis ◽  
Endocytic Activity

The Leydig cells of the rat testis which are involved in testosterone production contain an abundance of smooth endoplasmic reticulum and mitochondria (Figs. 2,6). These cells also possess many peroxisomes, lysosomes and multivesicular bodies (MVB's). On the cell surface, the plasma membrane contains numerous short microvilli, small invaginations and large plasmalemmal folds which appear to engulf extracellular fluid. There are also many large dilated vacuoles adjacent to the cell surface. The purpose of the present study is to determine if these cells show endocytic activity and to differentiate by various cytochemical means lysosomal elements from peroxisomes.To identify lysosomes, tissue chopper sections of 2% glutaraldehyde-fixed testes (containing 2.5% dextran) were incubated in media containing thiamine monophosphate as a substrate (Lalli, 1983) to demonstrate the presence of acid phosphatase or in media containing P-nitrocatechol sulfate for the demonstration of arylsulfatase (Hopsu-Havu et al., 1967).

Enhanced cell membrane enrichment and subsequent cellular internalization of quantum dots via cell surface engineering: illuminating plasma membranes with quantum dots

2016 ◽  
Vol 4 (5) ◽  
pp. 834-843 ◽  
Author(s):  
Hong-Yin Wang ◽  
Xian-Wu Hua ◽  
Hao-Ran Jia ◽  
Peidang Liu ◽  
Ning Gu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Plasma Membrane ◽  
Cell Membrane ◽  
Cell Surface ◽  
Hydrophobic Interaction ◽  
Plasma Membranes ◽  
Surface Engineering ◽  
Cellular Internalization ◽  
Cell Surface Engineering

Through hydrophobic interaction-based cell surface engineering, enhanced plasma membrane enrichment and subsequent cellular internalization of quantum dots were achieved.

Changes Occur in Plasma Membrane Turnover when K562 Leukemia Cells are Induced to Differentiate

1982 ◽  
Vol 40 ◽  
pp. 286-287
Author(s):  
L. M. Marshall
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Intracellular Transport ◽  
Parent Cell ◽  
Membrane Turnover ◽  
Coated Pits ◽  
Surface Distribution ◽  
Specific Proteins ◽  
Erythroleukemic Cell ◽  
Specific Membrane

A human erythroleukemic cell line, metabolically blocked in a late stage of erythropoiesis, becomes capable of differentiation along the normal pathway when grown in the presence of hemin. This process is characterized by hemoglobin synthesis followed by rearrangement of the plasma membrane proteins and culminates in asymmetrical cytokinesis in the absence of nuclear division. A reticulocyte-like cell buds from the nucleus-containing parent cell after erythrocyte specific membrane proteins have been sequestered into its membrane. In this process the parent cell faces two obstacles. First, to organize its erythrocyte specific proteins at one pole of the cell for inclusion in the reticulocyte; second, to reduce or abolish membrane protein turnover since hemoglobin is virtually the only protein being synthesized at this stage. A means of achieving redistribution and cessation of turnover could involve movement of membrane proteins by a directional lipid flow. Generation of a lipid flow towards one pole and accumulation of erythrocyte-specific membrane proteins could be achieved by clathrin coated pits which are implicated in membrane endocytosis, intracellular transport and turnover. In non-differentiating cells, membrane proteins are turned over and are random in surface distribution. If, however, the erythrocyte specific proteins in differentiating cells were excluded from endocytosing coated pits, not only would their turnover cease, but they would also tend to drift towards and collect at the site of endocytosis. This hypothesis requires that different protein species are endocytosed by the coated vesicles in non-differentiating than by differentiating cells.

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