Caffeic acid phenolipids in the protection of cell membranes from oxidative injuries. Interaction with the membrane phospholipid bilayer

2021 ◽  
pp. 183727
Author(s):  
Rafaela Lopes ◽  
Marlene Costa ◽  
Mariana Ferreira ◽  
Paula Gameiro ◽  
Sara Fernandes ◽  
...  
Keyword(s):  
Caffeic Acid ◽  
Cell Membranes ◽  
Phospholipid Bilayer ◽  
Membrane Phospholipid

scholarly journals Why Is Very High Cholesterol Content Beneficial for the Eye Lens but Negative for Other Organs?

Nutrients ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1083 ◽  
Author(s):  
Justyna Widomska ◽  
Witold K. Subczynski
Keyword(s):  
Cell Membranes ◽  
Plasma Membranes ◽  
Pathological Condition ◽  
Cholesterol Content ◽  
Phospholipid Bilayer ◽  
Human Lens ◽  
Lens Fiber Cell ◽  
Cholesterol Crystals ◽  
Pure Cholesterol ◽  
Cholesterol Solubility

The plasma membranes of the human lens fiber cell are overloaded with cholesterol that not only saturates the phospholipid bilayer of these membranes but also leads to the formation of pure cholesterol bilayer domains. Cholesterol level increases with age, and for older persons, it exceeds the cholesterol solubility threshold, leading to the formation of cholesterol crystals. All these changes occur in the normal lens without too much compromise to lens transparency. If the cholesterol content in the cell membranes of other organs increases to extent where cholesterol crystals forma, a pathological condition begins. In arterial cells, minute cholesterol crystals activate inflammasomes, induce inflammation, and cause atherosclerosis development. In this review, we will indicate possible factors that distinguish between beneficial and negative cholesterol action, limiting cholesterol actions to those performed through cholesterol in cell membranes and by cholesterol crystals.

scholarly journals Yeast phosphatidic acid phosphatase Pah1 hops and scoots along the membrane phospholipid bilayer

2020 ◽  
Vol 61 (8) ◽  
pp. 1232-1243 ◽  
Author(s):  
Joanna M. Kwiatek ◽  
George M. Carman
Keyword(s):  
Phosphatase Activity ◽  
Membrane Surface ◽  
Phospholipid Composition ◽  
Phospholipid Bilayer ◽  
Membrane Phospholipid ◽  
Membrane Phospholipids ◽  
Fatty Acyl Moiety ◽  
Triacylglycerol Synthesis ◽  
Er Membrane

PA phosphatase, encoded by PAH1 in the yeast Saccharomyces cerevisiae, catalyzes the Mg2+-dependent dephosphorylation of PA, producing DAG at the nuclear/ER membrane. This enzyme plays a major role in triacylglycerol synthesis and in the regulation of phospholipid synthesis. As an interfacial enzyme, PA phosphatase interacts with the membrane surface, binds its substrate, and catalyzes its reaction. The Triton X-100/PA-mixed micellar system has been utilized to examine the activity and regulation of yeast PA phosphatase. This system, however, does not resemble the in vivo environment of the membrane phospholipid bilayer. We developed an assay system that mimics the nuclear/ER membrane to assess PA phosphatase activity. PA was incorporated into unilamellar phospholipid vesicles (liposomes) composed of the major nuclear/ER membrane phospholipids, PC, PE, PI, and PS. We optimized this system to support enzyme-liposome interactions and to afford activity that is greater than that obtained with the aforementioned detergent system. Activity was regulated by phospholipid composition, whereas the enzyme’s interaction with liposomes was insensitive to composition. Greater activity was attained with large (≥100 nm) versus small (50 nm) vesicles. The fatty-acyl moiety of PA had no effect on this activity. PA phosphatase activity was dependent on the bulk (hopping mode) and surface (scooting mode) concentrations of PA, suggesting a mechanism by which the enzyme operates along the nuclear/ER membrane in vivo.

Membrane-disordering effects of β-amyloid peptides

2001 ◽  
Vol 29 (4) ◽  
pp. 617-623 ◽  
Author(s):  
W. E. Müller ◽  
C. Kirsch ◽  
G. P. Eckert
Keyword(s):  
Cell Membranes ◽  
Biological Effects ◽  
Senile Plaques ◽  
Initial Step ◽  
Phospholipid Bilayer ◽  
Membrane Properties ◽  
Major Constituent ◽  
Amyloid Peptides ◽  
Low Concentrations ◽  
Β Amyloid

β-Amyloid (Aβ) protein is the major constituent of senile plaques and cerebrovascular deposits characteristic of Alzheimer's disease (AD). The causal relationship between Aβ and AD-specific lesions like neurodegeneration and atrophy is still not known. The present article summarizes our studies indicating that rather low concentrations of Aβ significantly alter the fluidity of cell membranes and subcellular fractions from different tissues and different species including humans, as a possible initial step of its biological effects. Using different fluorescent probes our data show clearly that Aβ peptides specifically disturb the acylchain layer of cell membranes in a very distinct fashion. By contrast, membrane properties at the level of the polar heads of the phospholipid bilayer at the interface with membrane proteins are much less affected.

scholarly journals The study of the phospholipid bilayer state of cell membranes in leukocytes of rats after oral consumption of E407a food additive

2021 ◽  
Vol 20 (1) ◽  
pp. 40-45
Author(s):  
A.S. Tkachenko ◽  
◽  
Y.A. Posokhov ◽  
◽  
Keyword(s):  
Cell Membranes ◽  
Food Additive ◽  
Phospholipid Bilayer ◽  
Oral Consumption

Целью работы было оценить влияние перорально вводимого полуочищенного каррагинана (E407a) на гидрофобный участок фосфолипидного бислоя клеточных мембран лейкоцитов периферической крови. Материал и методы. Флуоресцентный зонд (2-фенилфенантро[9,10-d]-1,3-оксазол) был использован для оценки состояния липидного бислоя мембран лейкоцитов, полученных от 8 взрослых крыс-самок линии WAG, которые перорально получали полуочищенный каррагинан в дозировке 140 мг на кг веса в течение 2 недель, и 8 контрольных животных. Результаты. В ходе проведения работы установлено, что заметных изменений формы спектров флуоресценции зонда в ответ на пероральное введение полуочищенного каррагинана не наблюдалось. Это указывает на то, что пероральный прием E407a не вызывает изменений протонодонорной способности среды в липидных мембранах лейкоцитов в области расположения зонда. Уменьшение интенсивности флуоресценции зонда у крыс, которым перорально вводили пищевую добавку E407a, связано с уменьшением количества молекул зонда, которые связались с мембранами в течение 1 ч инкубации. Заключение. Пероральное употребление полуочищенного каррагинана не вызывает изменений гидратации гидрофобного участка фосфолипидного бислоя мембран лейкоцитов.

scholarly journals Detection of Escherichia Coli Using PCR Analysis Without DNA Extraction

2021 ◽  
Vol 57 (2) ◽  
pp. 147
Author(s):  
Wimbuh Tri Widodo ◽  
Choirul Huda
Keyword(s):  
Escherichia Coli ◽  
Dna Extraction ◽  
Cell Membranes ◽  
Dna Isolation ◽  
Phospholipid Bilayer ◽  
Pcr Analysis ◽  
Escherichia Coli Cells ◽  
Escherichia Coli Bacteria ◽  
Two Stages ◽  
Bacteria Culture

This study aimed to detect Escherichia coli directly without DNA extraction. The nucleus membrane and cell membranes of the Escherichia coli are composed of a phospholipid bilayer, damaged if heated at 950C. Pre-denaturation and denaturation of PCR were carried out at 950C. The two stages are thought to break down the Escherichia coli cells, so that the DNA that comes out of the cells can directly become a template in the PCR analysis. In this study, PCR analysis was carried out using Escherichia coli culture, Escherichia coli bacteria culture incubated at 950C, and Escherichia coli bacteria cultures incubated at 650C + on ice as templates. The results showed that PCR analysis using Escherichia coli culture directly and Escherichia coli culture incubated at 650C + on ice as templates produced very thin DNA bands with a size of 580 bp. while PCR analysis using Escherichia coli bacteria culture incubated at 950C as a template produced thick DNA bands with a size of 580 bp. This study's results are very useful for saving time and costs in the detection of Escherichia coli bacteria. The sample to be tested does not need DNA isolation as usual, but only needs to be incubated at 950C for 10 minutes.

scholarly journals Membrane phospholipid bilayer as a determinant of monoacylglycerol lipase kinetic profile and conformational repertoire

2013 ◽  
Vol 22 (6) ◽  
pp. 774-787 ◽  
Author(s):  
Mahmoud L. Nasr ◽  
Xiaomeng Shi ◽  
Anna L. Bowman ◽  
Michael Johnson ◽  
Nikolai Zvonok ◽  
...  
Keyword(s):  
Phospholipid Bilayer ◽  
Membrane Phospholipid ◽  
Monoacylglycerol Lipase ◽  
Kinetic Profile

scholarly journals Factors affecting the ability of glycosylphosphatidylinositol-specific phospholipase D to degrade the membrane anchors of cell surface proteins

1991 ◽  
Vol 279 (2) ◽  
pp. 483-493 ◽  
Author(s):  
M G Low ◽  
K S Huang
Keyword(s):  
Alkaline Phosphatase ◽  
Cell Surface ◽  
Phospholipase D ◽  
Bovine Serum ◽  
Cell Membranes ◽  
Surface Proteins ◽  
Phospholipid Bilayer ◽  
Placental Alkaline Phosphatase ◽  
Gpi Anchor ◽  
Cell Surface Proteins

Mammalian serum and plasma contain high levels of glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD). Previous studies with crude serum or partially purified GPI-PLD have shown that this enzyme is capable of degrading the GPI anchor of several purified detergent-solubilized cell surface proteins yet is unable to act on GPI-anchored proteins located in intact cells. Treatment of intact ROS17/2.8, WISH or HeLa cells (or membrane fractions prepared from them) with GPI-PLD purified from bovine serum by immunoaffinity chromatography gave no detectable release of alkaline phosphatase into the medium. However, when membranes were treated with GPI-PLD in the presence of 0.1% Nonidet P-40 substantial GPI anchor degradation (as measured by Triton X-114 phase separation) was observed. The mechanism of this stimulatory effect of detergent was further investigated using [3H]myristate-labelled variant surface glycoprotein and human placental alkaline phosphatase reconstituted into phospholipid vesicles. As with the cell membranes the reconstituted substrates exhibited marked resistance to the action of purified GPI-PLD which could be overcome by the inclusion of Nonidet P-40. Similar results were obtained when crude bovine serum was used as the source of GPI-PLD. These data indicate that the resistance of cell membranes to the action of GPI-PLD is not entirely due to the action of serum or membrane-associated inhibitory factors. A more likely explanation is that, in common with many other eukaryotic phospholipases, the action of GPI-PLD is restricted by the physical state of the phospholipid bilayer in which the substrates are embedded. These data may account for the ability of endothelial and blood cells to retain GPI-anchored proteins on their surfaces in spite of the high levels of GPI-PLD present in plasma.

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