scholarly journals Image Analysis Study of Aluminum Effects on Osmotic Behavior of Red Beet (Beta vulgaris L.) Protoplasts

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 899B-899
Author(s):  
Young Sang Lee ◽  
G Mitiku ◽  
A.G. Endress
Keyword(s):  
Image Analysis ◽  
Plasma Membrane ◽  
Membrane Surface ◽  
Biophysical Properties ◽  
Cross Sectional ◽  
Membrane Surface Area ◽  
Analysis Study ◽  
Red Beet ◽  
Osmotic Behavior ◽  
Plasma Membrane Surface

The hypothesis that Al3+ interferes with membrane biophysical properties has been tested. Plasma membrane expansion/contraction in protoplasts isolated from red beet was induced by decreasing or increasing the osmolarity of extracellular solutions. The percentage of Iysed protoplasts was measured to characterize the effects of Al3+ on the ability of protoplasts to increase their plasma membrane surface area. In control solutions (800 mM sorbitol), 31.4% of protoplasts Iysed following osmotic dilution from 1200 mM. Al3+ treatment (5 mM) decreased the proportion of Iysed protoplasts by 7.7% and Ca2+ (5 mM) by 17% compared to control. Lanthanum (La3+), however, proved to be the most efficient ion for protection against Iysis (3.3%). Under hypertonic solutions, Al3+ treatment helped protoplasts maintain their roundness, diameter, and cross-sectional area compared to the control (1.5 M sorbitol), thus, altering the protoplasts “roundness” as determined by image analysis parameters. The results suggest that a decrease in the proportion of Iysed protoplasts in the presence of Al3+ may be induced due to changes in membrane permeability to water.

PLATELET EXTERNAL SURFACE MEMBRANE IS OSMOTICALLY DOUBLED IRRESPECTIVE OF SIZE OR SPECIES (HUMAN/BOVINE): DYNAMICS AND MEMBRANE SOURCES

1987 ◽  
Author(s):  
Mony M Frojmovic ◽  
Truman Wong ◽  
Jane Wylie ◽  
J G White
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Shape Change ◽  
Membrane Surface ◽  
Surface Membrane ◽  
Osmic Acid ◽  
Osmotic Swelling ◽  
Membrane Surface Area ◽  
Water Dilution ◽  
Plasma Membrane Surface

Osmotic swelling can double the external plasma membrane surface area of human platelets independently of size, proposed to recruit the open surface-connected canalicular system ((SCCS) (Thrombos. Res. Suppl. VI: 119, 1986). As bovine (B) platelets have been reported to lack SCCS, we compared osmotic swelling for B and human (H) cells. Addition of water to piatelet-rich-plasma (10-90% v/v) caused sequential shape change and osmotic spherocyte (OS) formation, analyzed for size and surface area changes from time-dependent phase-contrast videomicroscopic images. Selected samples were fixed and stained with tannic acid prior to osmic acid fixation for visualization of open SCCS by transmission electron microscopy. B platelets required 3-4x less water dilution of PRP than H platelets, with significant OS forming at 20% water addition. Continued water dilution converted 50% of platelets to OS, with maximally stable swelling and no significant lysis for bovine OS up to 60% dilution. Electron micrographs of unactivated discocytes (D) and of optimally-swollen OS showed open SCCS in human D not detectable in any of the swollen platelets, though granules, mitochondria and a small number of vesicles and vacuoles persisted; no evidence for any open SCCS was found for bovine D or OS, though the OS otherwise appeared similar to H-0S. Geometric measurements of D and nonlysed OS showed a stable, maximal 2.1±0.1 fold increase in external plasma membrane surface area with osmotic swelling, identical for different-sized H platelets (mean volume = 2.8-6.8 f1) or for B platelets (3.6 f1 ). B platelets show equal or greater sensitivity for ADP-induced activation as H platelets, with 2-fold slower maximal rates of recruitment in early aggregation. As osmotic swelling appears to primarily externalize SCCS in H platelets, the identical relative amounts of internal membrane externalized for B platelets is hypothesized to arise from an osmotically more labile, “closed”, and structurally simpler SCCS or from a distinct membrane source tnan in H platelets.

scholarly journals Correlation of Na+,K+-ATPase content and plasma membrane surface area in adapted and de-adapted salt glands of ducklings

1985 ◽  
Vol 78 (1) ◽  
pp. 233-246 ◽  
Author(s):  
J.L. Merchant ◽  
D.S. Papermaster ◽  
R.J. Barrnett
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Salt Water ◽  
Membrane Surface ◽  
Salt Gland ◽  
Principal Cell ◽  
Membrane Surface Area ◽  
Principal Cells ◽  
Basolateral Plasma Membrane ◽  
Plasma Membrane Surface

During salt-water adaptation, an increase occurs in Na+,K+-ATPase content and surface area of the basolateral plasma membrane of the principal cell of the duck salt gland. To determine the degree to which these changes are correlated, accepted morphometric methods were used to determine numerical cell densities and plasma membrane surface densities of peripheral and principal cells. After adaptation, the plasma membrane surface area per principal cell was five times greater than in controls. Following de-adaptation, the plasma membrane content in principal cells returned to 1.9 times control levels. Two other cell constituents, mitochondria and lipid droplets, displayed similar quantitative changes. Na+,K+-ATPase content increased about fourfold with adaptation and decreased to near control levels with de-adaptation. Thus, changes in Na+,K+-ATPase content and basolateral plasma membrane surface area in adapting and de-adapting secretory epithelia of the salt gland occur nearly in parallel. These quantitative data enable Na+,K+-ATPase synthesis and degradation to be investigated in relation to membrane biogenesis.

scholarly journals Paracrystalline arrays of membrane-to-membrane cross bridges associated with the inner surface of plasma membrane

1978 ◽  
Vol 77 (2) ◽  
pp. 323-328 ◽  
Author(s):  
WW Franke ◽  
C Grund ◽  
E Schmid ◽  
E Mandelkow
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Cultured Cells ◽  
Membrane Surface ◽  
Hexagonal Lattice ◽  
Interparticle Distance ◽  
Macromolecular Complexes ◽  
Inner Surface ◽  
Cross Bridges ◽  
Plasma Membrane Surface

In cultured cells of the rat kangaroo PtK2 line, veils of the cell surface were observed which consisted of only plasma membrane and paracrystalline arrays of membrane-associated particles sandwiched in between. These membrane-to-membrane cross-bridging 9-to 11-nm wide particles were somewhat coumellar-shaped and were arranged on a hexagonal lattice with an interparticle distance of 16nm. At higher magnification, they revealed an unstained core, thus suggesting a ringlike substructure. Similar arrays of paracrystal-containing veils, which were rather variable in size and frequency, were also observed in other cultured cells. It is hypothesized that these paracrystals represent protein macromolecular complexes associated with the inner plasma membrane surface which crystallize when plasma membranes come into close intracellular contact and other components of the subsurface network are removed.

The influence of differentiation-inducing agents on plasma membrane surface characteristics of THP-1 cells

2011 ◽  
Vol 5 (2) ◽  
pp. 135-142
Author(s):  
S. V. Zubova ◽  
D. S. Kabanov ◽  
A. Yu. Ivanov ◽  
E. V. Voloshina ◽  
I. I. Proskuryakov ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Surface ◽  
Surface Characteristics ◽  
Plasma Membrane Surface
Sign in / Sign up

Export Citation Format

Share Document