scholarly journals Phospholipid Composition of a Plasma Membrane-Enriched Fraction from Developing Soybean Roots

1985 ◽  
Vol 79 (2) ◽  
pp. 494-498 ◽  
Author(s):  
Carol E. Whitman ◽  
Robert L. Travis
Keyword(s):  
Plasma Membrane ◽  
Phospholipid Composition ◽  
Soybean Roots

Purification of distinct plasma membranes from canine renal medulla

1978 ◽  
Vol 234 (3) ◽  
pp. F247-F254
Author(s):  
R. Iyengar ◽  
D. S. Mailman ◽  
G. Sachs
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Specific Activity ◽  
Collecting Duct ◽  
Gradient Centrifugation ◽  
Phospholipid Composition ◽  
Renal Medulla ◽  
Similar Distribution ◽  
Mitochondrial Atpase ◽  
Fold Enrichment

Two types of plasma membrane were purified from canine distal renal medulla by the techniques of differential and zonal density-gradient centrifugation followed by free-flow electrophoresis. One group of plasma membranes was identified as basal-laterally derived based on a 30-fold enrichment of Na-K-ATPase, a 20-fold enrichment of vasopressin-stimulated adenylate cyclase, and a 33-fold enrichment of [3H]vasopressin binding sites. The second type of plasma membrane was free of these markers, but had a cholesterol and phospholipid composition similar to them. Alkaline phosphatase also had a similar distribution in the two fractions. This lighter membrane fraction contained a membrane-bound cyclic AMP-dependent protein kinase as well as substrate for this kinase. In addition there was a 26-fold enrichment of specific activity of an anion (SO32-)-activated ATPase which was insensitive to mitochondrial ATPase inhibitor protein, in contrast to the mitochondrial fraction of the tissue. Based on the relative preponderance of collecting duct tissue in the distal medulla and the yield of membrane protein, these membranes are tentatively identified as containing apical membranes of the collecting duct.

scholarly journals Bicarbonate-Stimulated Membrane Reorganization in Stallion Spermatozoa

2021 ◽  
Vol 9 ◽  
Author(s):  
Paula Piccolo Maitan ◽  
Elizabeth G. Bromfield ◽  
Romy Hoogendijk ◽  
Miguel Ricardo Leung ◽  
Tzviya Zeev-Ben-Mordehai ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Fluidity ◽  
Electron Tomography ◽  
Mammalian Species ◽  
Phospholipid Composition ◽  
Defined Medium ◽  
Vital Role ◽  
Membrane Reorganization ◽  
Viable Sperm

Classical in vitro fertilization (IVF) is still poorly successful in horses. This lack of success is thought to be due primarily to inadequate capacitation of stallion spermatozoa under in vitro conditions. In species in which IVF is successful, bicarbonate, calcium, and albumin are considered the key components that enable a gradual reorganization of the sperm plasma membrane that allows the spermatozoa to undergo an acrosome reaction and fertilize the oocyte. The aim of this work was to comprehensively examine contributors to stallion sperm capacitation by investigating bicarbonate-induced membrane remodelling steps, and elucidating the contribution of cAMP signalling to these events. In the presence of capacitating media containing bicarbonate, a significant increase in plasma membrane fluidity was readily detected using merocyanine 540 staining in the majority of viable spermatozoa within 15 min of bicarbonate exposure. Specific inhibition of soluble adenylyl cyclase (sAC) in the presence of bicarbonate by LRE1 significantly reduced the number of viable sperm with high membrane fluidity. This suggests a vital role for sAC-mediated cAMP production in the regulation of membrane fluidity. Cryo-electron tomography of viable cells with high membrane fluidity revealed a range of membrane remodelling intermediates, including destabilized membranes and zones with close apposition of the plasma membrane and the outer acrosomal membrane. However, lipidomic analysis of equivalent viable spermatozoa with high membrane fluidity demonstrated that this phenomenon was neither accompanied by a gross change in the phospholipid composition of stallion sperm membranes nor detectable sterol efflux (p > 0.05). After an early increase in membrane fluidity, a significant and cAMP-dependent increase in viable sperm with phosphatidylserine (PS), but not phosphatidylethanolamine (PE) exposure was noted. While the events observed partly resemble findings from the in vitro capacitation of sperm from other mammalian species, the lack of cholesterol removal appears to be an equine-specific phenomenon. This research will assist in the development of a defined medium for the capacitation of stallion sperm and will facilitate progress toward a functional IVF protocol for horse gametes.

scholarly journals Interaction of phospholipid vesicles with cells. Endocytosis and fusion as alternate mechanisms for the uptake of lipid-soluble and water-soluble molecules.

1975 ◽  
Vol 66 (3) ◽  
pp. 621-634 ◽  
Author(s):  
S Batzri ◽  
E D Korn
Keyword(s):  
Plasma Membrane ◽  
Phospholipid Composition ◽  
Acanthamoeba Castellanii ◽  
Water Soluble ◽  
Phospholipid Bilayer ◽  
Electron Microscope Autoradiography ◽  
Cytoplasmic Vacuoles ◽  
Egg Lecithin ◽  
Microscope Autoradiography ◽  
Dipalmitoyl Lecithin

Depending on their phospholipid composition, liposomes are endocytosed by, or fuse with, the plasma membrane, of Acanthamoeba castellanii. Unilamellar egg lecithin vesicles are endocytosed by amoeba at 28 degrees C with equal uptake of the phospholipid bilayer and the contents of the internal aqueous space of the vesicles. Uptake is inhibited almost completely by incubation at 4 degrees C or in the presence of dinitrophenol. After uptake at 28 degrees C, the vesicle phospholipid can be visualized by electron microscope autoradiography within cytoplasmic vacuoles. In contrast, uptake of unilamellar dipalmitoyl lecithin vesicles and multilamellar dipalmitoyl lecithin liposomes is only partially inhibited at 4 degrees C, by dinitrophenol and by prior fixation of the amoebae with glutaraldehyde, each of which inhibits pinocytosis. Vesicle contents are taken up only about 40% as well as the phospholipid bilayer. Electron micrographs are compatible with the interpretation that dipalmitoyl lecithin vesicles fuse with the amoeba plasma membrane, adding their phospholipid to the cell surface, while their contents enter the cell cytoplasm. Dimyristoyl lecithin vesicles behave like egg lecithin vesicles while distearoyl lecithin vesicles behave like dipalmitoyl lecithin vesicles.

scholarly journals The fluidity of normal and virus-transformed cell plasma membrane

1976 ◽  
Vol 154 (3) ◽  
pp. 561-566 ◽  
Author(s):  
K J. Micklem ◽  
R M. Abra ◽  
S Knutton ◽  
J M Graham ◽  
C A Pasternak
Keyword(s):  
Plasma Membrane ◽  
Phospholipid Composition ◽  
British Library ◽  
Oncogenic Viruses ◽  
Cell Plasma Membrane ◽  
Bhk Cells ◽  
Receptor Sites ◽  
Cell Plasma ◽  
Significant Difference ◽  
Phospholipid Ratio

1. The phospholipid composition and cholesterol/phospholipid ratio of plasma membrane is the same in normal as in transformed BHK (baby-hamster kidney) cells; no significant difference in length or degree of unsaturation of the contributing acyl chains is apparent. 2. The turnover of acetate-labelled phosphatidylcholine species in the plasma membrane of normal and transformed BHK cells is the same. 3. Intramembranous particles of normal and transformed 3T3-cell plasma membrane are randomly distributed, whether at 4degreesC or at 37degreesC, in sparse or in dense cultures. There is no correlation between distribution of particles and the movement of concanavalin A receptor sites. 4. It is concluded that transformation of fibroblastic cells by oncogenic viruses does not lead to major changes in the lipid fluidity of the plasma membrane. 5. Details of the phospholipid composition of nuclei, mitochondria and endoplasmic reticulum in normal and transformed BHK cells have been deposited as Supplementary Publication SUP 50061 (5 pages) at the British Library Lending Division, Boston, Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1976) 153, 5.

scholarly journals Auxin enhances aluminium-induced citrate exudation through upregulation ofGmMATEand activation of the plasma membrane H+-ATPase in soybean roots

2016 ◽  
Vol 118 (5) ◽  
pp. 933-940 ◽  
Author(s):  
Ping Wang ◽  
Wenqian Yu ◽  
Jiarong Zhang ◽  
Zed Rengel ◽  
Jin Xu ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Soybean Roots ◽  
Citrate Exudation
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