Changes in the phospholipid composition of cat hepatocyte plasma membrane in hemorrhagic shock

1997 ◽  
Vol 123 (3) ◽  
pp. 224-226
Author(s):  
G. F. Leskova ◽  
V. I. Udovichenko
Keyword(s):  
Plasma Membrane ◽  
Hemorrhagic Shock ◽  
Phospholipid Composition

Hemorrhagic shock recruits Toll-like receptor 4 to the plasma membrane in macrophages: A novel mechanism of cell priming for LPS signaling

2005 ◽  
Vol 201 (3) ◽  
pp. S36
Author(s):  
Kinga A. Powers ◽  
Katalin Szaszi ◽  
Rachel Khadaroo ◽  
Patrick Tawadros ◽  
John C. Marshall ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Hemorrhagic Shock ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Lps Signaling

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.

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