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The aim of this study was to compare the content of fatty acids in ostrich back, breast and abdominal depot fat. Experimental material consisted of 20 Blue Neck ostriches coming from a private farm in Poland. Ostriches were slaughtered at the age of 12 months and abdominal, breast and back fat depot samples (from each bird) were evaluated for fatty acids composition. Fat from the back and the breast regions had a higher content of saturated fatty acids and these differences were statistically significant (P≤0.01) in relation to abdominal fat. Among saturated fatty acids, palmitic and stearic acids were found in the greatest amount, constituting 40.1 and 5.2% of total fatty acids, respectively. In the group of monounsaturated acids, oleic and palmitooleic acids were predominant, with the average content of 28.8 and 7.9% of total fatty acid content, respectively. The total PUFA content was on average 16.5% of total fatty acids, with linoleic acid being found in the greatest amount. [ABSTRACT FROM AUTHOR]

The interaction of beta-cyclodextrin (beta-CD) with mixed bilayers composed of sphingomylein and cholesterol (Chol) above and below the accepted stable complexation ratio (67:33) was investigated. Membranes with the same (symmetric) and different (asymmetric) compositions in their inner and outer leaflets were deposited at surface pressures of 20, 30, and 40 mN/m at the solid-liquid interface. Using neutron reflectometry, membranes of various global molar ratios (defined as the sum of the molar ratios of the inner and outer leaflets), were characterized before and after beta-CD was added to the subphase. The structure of bilayers with global molar ratios at or above the stable complexation ratio was unchanged by beta-CD, indicating that beta-CD is unable to remove sphingomyelin or complexed Chol. However, beta-CD removed all uncomplexed Chol from bilayers composed of global molar ratios below the stable complexation ratio. The removal of Chol by beta-CD was independent of the initial structure of the membranes as deposited, suggesting that asymmetric membranes homogenize by the exchange of molecules between leaflets. The interaction of beta-CD with the aforementioned membranes was independent of the deposition surface pressure except for a symmetric 50:50 membrane deposited at 40 mN/m. The scattering from 50:50 bilayers with higher packing densities (deposited at 40 mN/m) was unaffected by beta-CD, suggesting that the removal of Chol can depend on both the composition and packing density of the membrane., (Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

Sterols are essential constituents of membranes, both in the plant world and in human organisms. Therefore, their activity on model lipid systems has systematically been studied. Despite intensive investigations, differences in the effect induced by beta-sitosterol (beta-sito) and stigmasterol (stigma) (two major phytosterols) are very controversial and still under debate. To compare the influence of these compounds on model membranes, we have performed grazing incidence X-ray diffraction (GIXD) experiments on phytosterol/sphingomyelin (Sph) monolayers. The analysis of the X-ray scattering and the resulting in-plane parameters provided information on the lateral organization of pure lipid films and the mixed systems. The obtained results prove a nonideal mixing between the investigated lipids in the monolayers and the existence of strong interactions between phytosterols and Sph. Both the plant sterols incorporated into sphingolipid film condense the monolayer and order Sph chains. The results of GIXD experiments, compared with those obtained previously from Langmuir monolayer studies allowed us to observe the comparable influence of beta-sito and stigma on model membrane organization.