Raman study of lipid phase state in freezing mammalian embryos and oocytes

Abstract Interaction of the antenna protein B 800-850 with the lipid environment and with the reaction center of the photosynthetic bacterium Rhodopseudomonas sphaeroides is studied by fluorescence spectroscopy, transient absorption techniques, light scattering and electron microscopy. Using vesicles of synthetic phospholipids it is shown that solidification of the m em brane causes a structural protein change evident from a reduction in fluorescence quantum yield. The change occurs at a tem perature up to 5 °C below that corresponding to the gel/fluid transition tem perature and indicates local melting. The structural change is not specific for the lipid head group nor chain length (investigated for lengths of 12 to 16 CH2 groups) and can be understood applying a simple elastic model. It can also be included isothermally by changing the ionic milied and thus varying the lipid phase state. Energy transfer LHCP→RC is proven to be highly efficient in model m em branes and is not affected by the existence of a phase transition. This indicates two LHCP fractions one tightly - and one non-bound to the RC.

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Lipolysis of phospholipids in model cholesteryl ester rich lipoproteins and related systems: effect of core and surface lipid phase state

Biochemistry ◽

10.1021/bi00414a051 ◽

1988 ◽

Vol 27 (14) ◽

pp. 5290-5295 ◽

Cited By ~ 9

Author(s):

Martha P. Mims ◽

Joel D. Morrisett

Keyword(s):

Cholesteryl Ester ◽

Phase State ◽

Lipid Phase ◽

Surface Lipid

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Lipid droplet phase transition in freezing cat embryos and oocytes probed by Raman spectroscopy

10.1101/275164 ◽

2018 ◽

Cited By ~ 1

Author(s):

K.A. Okotrub ◽

V.I. Mokrousova ◽

S.Y. Amstislavsky ◽

N.V. Surovtsev

Keyword(s):

Phase Transition ◽

Raman Spectroscopy ◽

Lipid Droplets ◽

Phase State ◽

Domestic Cat ◽

Lipid Phase ◽

Lipid Phase Transition ◽

Lipid Molecule ◽

Early Embryos ◽

Lipid Unsaturation

ABSTRACTEmbryo and oocyte cryopreservation is a widely used technology for cryopreservation of genetic resources. One challenging limitation of this technology is the cell damage during freezing associated with the intracellular lipid droplets. We exploit a Raman spectroscopy to investigate the freezing of cumulus-oocyte complexes, mature oocytes and early embryos of a domestic cat. All these cells are rich in lipids. The degree of lipid unsaturation, lipid phase transition from liquid-like disordered to solid-like ordered state (main transition) and triglyceride polymorphic state are studied. For all cells examined, the average degree of lipid unsaturation is estimated about 1.3 (with ±20 % deviation) double bonds per acyl chain. The onset of the main lipid phase transition occurs in a temperature range from −10 to +4 °C and does not depend significantly on the cell type. It is found that lipid droplets in cumulus-oocyte complexes undergo an abrupt lipid crystallization, which not completely correlate with the ordering of lipid molecule acyl chains. In the case of mature oocytes and early embryos obtainedin vitrofrom cumulus-oocyte complexes, the lipid phase transition is broadened. In frozen state lipid droplets inside the cumulus-oocyte complexes have higher content of triglyceride polymorphic β and β′ phases (∼66%) than it is estimated for the mature oocytes and the early embryos (∼50%). For the first time, to our knowledge, temperature evolution of lipid droplets phase state is examined. Raman spectroscopy is proved as a prospective tool forin situmonitoring of lipid phase state in single embryo/oocyte during freezing.

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The Biosurfactant β-Aescin: A Review on the Physico-Chemical Properties and Its Interaction with Lipid Model Membranes and Langmuir Monolayers

Molecules ◽

10.3390/molecules25010117 ◽

2019 ◽

Vol 25 (1) ◽

pp. 117 ◽

Cited By ~ 7

Author(s):

Ramsia Geisler ◽

Carina Dargel ◽

Thomas Hellweg

Keyword(s):

Lipid Bilayers ◽

Lipid Membranes ◽

Phase State ◽

Chemical Properties ◽

Langmuir Monolayers ◽

Model Membranes ◽

Biologically Active ◽

Horse Chestnut ◽

Lipid Phase ◽

Gel Phase

This review discusses recent progress in physicochemical understanding of the action of the saponin β -aescin (also called β -escin), the biologically active component in the seeds of the horse chestnut tree Aesculus hippocastanum. β -Aescin is used in pharmacological and cosmetic applications showing strong surface activity. In this review, we outline the most important findings describing the behavior of β -aescin in solution (e.g., critical micelle concentration ( c m c ) and micelle shape) and special physicochemical properties of adsorbed β -aescin monolayers at the air–water and oil–water interface. Such monolayers were found to posses very special viscoelastic properties. The presentation of the experimental findings is complemented by discussing recent molecular dynamics simulations. These simulations do not only quantify the predominant interactions in adsorbed monolayers but also highlight the different behavior of neutral and ionized β -aescin molecules. The review concludes on the interaction of β -aescin with phospholipid model membranes in the form of bilayers and Langmuir monolayers. The interaction of β -aescin with lipid bilayers was found to strongly depend on its c m c . At concentrations below the c m c , membrane parameters are modified whereas above the c m c , complete solubilization of the bilayers occurs, depending on lipid phase state and concentration. In the presence of gel-phase phospholipids, discoidal bicelles form; these are tunable in size by composition. The phase behavior of β -aescin with lipid membranes can also be modified by addition of other molecules such as cholesterol or drug molecules. The lipid phase state also determines the penetration rate of β -aescin molecules into lipid monolayers. The strongest interaction was always found in the presence of gel-phase phospholipid molecules.

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