Essential lipids

Resistant to ether, chloroform, and bile salts, indicating lack of essential lipids... 

Between the free CSF space and the extracellular space there is a diffusion equilibrium for macromolecules. The intra/extracellular barrier and the blood-brain barrier are essentially lipid barriers, retaining small hydrophilic molecules but allowing the passage of lipophilic molecules up to approximately 500 Da... 

The Vo is made of subunits acc c"de. Subunits c, c, and c" are proteolipid isoforms each containing one essential lipid-exposed glutamate residue. The proteolipids in the V-ATPase are twice the size compared with the F-ATPase proteolipids, and it is assumed that the four transmembrane a helix c- and c -subunits are a result of an early gene fusion event. Subunit c" has two lipid-exposed glutamates, but only one of them is essential for proton pumping. The 100-kDa subunit a is a two-domain protein with a... 

Lipids also can be beneficial for cells in culture, since some substances absorbed by the cells need to be solubilized in lipids, or in some cases the toxicity of compounds may be reduced by complexation with lipids. The absence of essential lipids such as linoleic acid, lecithin, cholesterol, ethanolamine, or phosphorylcholine can result in the decrease of cloning efficiency and in reduction in the size of colonies, as shown for insect cells by Echalier (1997). However, one of the difficulties in supplying lipids at reasonable concentrations is their low solubility. To circumvent this limitation, lipids can be emulsified with complexing agents such as Pluronic F68 or cyclodextrin (Maiorella et al., 1998). 

Mene-Saffrane, L. Jones, A.D. DellaPeima, D. 2010. Plastocrhomanol-8 and tocopherols are essential lipid-soluble antioxidants during seed desiccation and quiescence in Arabidopsis. Proc. Natl. Acad. Sci. 41 17815-17820. 

Klein Breteler, W. C. M., Schogt, N., Baas, M., Schouten, S., and Kraay, G. W. (1999). Trophic upgrading of food quality by protozoans enhancing copepod growth Role of essential lipids. Mar. Biol. 135, 191-198. 

Other adverse physiological effects may show up, e.g. natural oils of plant origin contain a lot of lipid soluble vitamins. Replacement of natural oils by synthetic fats exempt of vitamins may influence the uptake of other lipids and lead to a plentitude of physiological disturbances due to lack of essential lipids and vitamins. 

Biological membranes are essentially lipid consequently, the rate at which drug molecules cross these barriers is dictated primarily by their lipid solubility. Molecular size and shape and the solubility at the site of absorption also directly affect the absorption of drugs. The other important factor that determines the ability of a drug to cross these biological barriers is the degree of ionization. 

Prebiotic synthesis likely contributed to the spectrum of compounds in a relative early phase of the Earth since exposure of methane and water to brush discharges resulted in the formation of monocarboxylic acids up to a length of 12 carbon atoms. The fact that essential lipids do have optical activity might indicate that they are of meteoritic origin. 

Dunstan, G.A., Volkman, J.K., and Maguire, G.B., 2000, Optimisation of Essential Lipids in Artificial Feeds for Australian Abalone, FRDC Project 94/85, CSIRO Marine Research, Fisheries Research and Development Corporation, 68. 

Azole antifungal compounds act by inhibiting the sterol l4-demethylase enzyme of the sterol biosynthetic pathway (Fig. 2). Sterols ate essential lipid components of eukaryotic membranes. Sterols are important regulators of membrane permeability and fluidity. In addition, sterols have roles in aerobic metabolism, completion of cell cycle, sterol uptake, and... 

Linoleic acid is one of the most important polyunsaturated fatty acids it is the essential lipid precursor to many vital biomolecules, such as prostaglandins, thromboxanes, lipoxins, and prostacyclins (1-5). All of these linoleic acid metabolites are unique molecules with either carbocyclic systems containing chiral carbon centers or unsaturated C-C systems of specific geometric configurations. These fatty acid metabolites perform highly specialized physiologic roles (6,7). 

Growth factor a growth-stimulating substance. The term is used in two distinct ways 1. nutrients such as vitamins, essential amino acids, essential lipids, inorganic ions, etc. or 2. a variety of non-nutri-ent, mitogenic substances. 

Thus it may be seen that the distribution between plasma and gastric juice is largely dependent on the value of the K. This is easily explained if one assures that the barrier separating the gastric juice from the plasma is essentially lipidic in nature. A weak base or a weak acid is present in the plasma (pH 74), both... 

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