Dependence of the bilayer to hexagonal phase transition on amphiphile chain length

Biochemistry ◽  
1989 ◽  
Vol 28 (24) ◽  
pp. 9398-9402 ◽  
Author(s):  
Richard M. Epand ◽  
Kelli S. Robinson ◽  
Marie E. Andrews ◽  
Raquel F. Epand
Keyword(s):  
Phase Transition ◽  
Chain Length ◽  
Hexagonal Phase

Bilayer stabilizing peptides and the inhibition of viral infection: antimeasles activity of carbobenzoxy-Ser-Leu-amide

1987 ◽  
Vol 7 (9) ◽  
pp. 745-749 ◽  
Author(s):  
Richard M. Epand ◽  
Thomas J. Lobl ◽  
H. E. Renis
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Phase Transition Temperature ◽  
Measles Virus ◽  
Cytopathic Effect ◽  
Hexagonal Phase ◽  
Vero Cells ◽  
Time Parameter ◽  
Scanning Calorimetry ◽  
Hplc Retention Time

A number of carbobenzoxy-dipeptide-amides raise the bilayer to hexagonal phase transition temperature of dielaidoylphosphatidylethanolamine (stabilizes the bilayer). The potency of the peptides in stabilizing the bilayer phase is Z-Tyr-Leu-NH2>Z-Gly-Phe-NH2>Z-Ser-Leu-NH2>Z-Gly-Leu-NH2>Z-Gly-Gly-NH2. A linear correlation was found between the respective HPLC retention time parameter k′ for the peptide and the slope of the bilayer stabilization curve determined with model membranes by differential scanning calorimetry. One dipeptide, Z-Ser-Leu-NH2, reduces measles virus cytopathic effect (CPE) in Vero cells. The mechanism by which this peptide reduces the CPE is not known, although some peptides which raise the bilayer to hexagonal phase transition temperature of phospholipids inhibit membrane fusion.

scholarly journals Pathological transitions in myelin membranes driven by environmental and multiple sclerosis conditions

2018 ◽  
Vol 115 (44) ◽  
pp. 11156-11161 ◽  
Author(s):  
Rona Shaharabani ◽  
Maor Ram-On ◽  
Yeshayahu Talmon ◽  
Roy Beck
Keyword(s):  
Multiple Sclerosis ◽  
Phase Transition ◽  
Lipid Composition ◽  
Environmental Conditions ◽  
Structural Changes ◽  
Environmental Changes ◽  
Hexagonal Phase ◽  
Structural Phase ◽  
Structural Modifications ◽  
Transition Points

Multiple sclerosis (MS) is an autoimmune disease, leading to the destruction of the myelin sheaths, the protective layers surrounding the axons. The etiology of the disease is unknown, although there are several postulated environmental factors that may contribute to it. Recently, myelin damage was correlated to structural phase transition from a healthy stack of lamellas to a diseased inverted hexagonal phase as a result of the altered lipid stoichiometry and low myelin basic protein (MBP) content. In this work, we show that environmental conditions, such as buffer salinity and temperature, induce the same pathological phase transition as in the case of the lipid composition in the absence of MBP. These phase transitions have different transition points, which depend on the lipid’s compositions, and are ion specific. In extreme environmental conditions, we find an additional dense lamellar phase and that the native lipid composition results in similar pathology as the diseased composition. These findings demonstrate that several local environmental changes can trigger pathological structural changes. We postulate that these structural modifications result in myelin membrane vulnerability to the immune system attacks and thus can help explain MS etiology.

scholarly journals Direct atomic identification of cation migration induced gradual cubic-to-hexagonal phase transition in Ge2Sb2Te5

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Yonghui Zheng ◽  
Yong Wang ◽  
Tianjiao Xin ◽  
Yan Cheng ◽  
Rong Huang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Hexagonal Phase ◽  
Cation Migration

Reactive HiPIMS deposition of Ti-Al-N: Influence of the deposition parameters on the cubic to hexagonal phase transition

2020 ◽  
Vol 382 ◽  
pp. 125007 ◽  
Author(s):  
L. Zauner ◽  
Ph. Ertelthaler ◽  
T. Wojcik ◽  
H. Bolvardi ◽  
S. Kolozsvári ◽  
...  
Keyword(s):  
Phase Transition ◽  
Hexagonal Phase ◽  
Deposition Parameters

Kinetics of the lamellar-inverse hexagonal phase transition determined by time-resolved x-ray diffraction

Biochemistry ◽  
1992 ◽  
Vol 31 (4) ◽  
pp. 1081-1092 ◽  
Author(s):  
Mark W. Tate ◽  
Erramilli Shyamsunder ◽  
Sol M. Gruner ◽  
Kevin L. D'Amico
Keyword(s):  
Phase Transition ◽  
Hexagonal Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Kinetics Of
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