Lipid residues

A consistent pericardial edema in chickens gave rise to the term chick edema disease (chick edema factor) (I). Two known outbreaks of the disease in the broiler industry resulted in a great loss of chickens. A lipid residue from the manufacturing fatty acids, being used as a feed ingredient, was a principal source of the toxic substance. Contamination of the lipid component with polychlorodibenzo-p-dioxins was attributed as the causal agent. 

Copley, M. S., Berstan, R., Dudd, S. N., Straker, V., Payne, S. and Evershed, R. P. (2005a) Dairying in antiquity. I. Evidence from absorbed lipid residues dating to the British Iron Age. Journal of Archaeological Science 32, 485 503. 

Mukherjee, A. J. (2004) The importance of pigs in the later British Neolithic integrating stable isotope evidence from lipid residues in archaeological potsherds, animal hones, and modem animal tissues. PhD Thesis, University of Bristol. 

By means of this method, a variety of Ras proteins with different lipidation patterns could be synthesized in multimilligram amounts. For instance, proteins were generated with the natural lipid combination, i.e. a farnesyl thioether and a palmitoyl thioester. Furthermore, analogous proteins were synthesized embodying only one lipid residue in which either the farnesyl- or the palmitoyl group was replaced by a stable hexadecyl thioether. In addition, proteins were built up containing a serine instead of a cysteine residue at the critical sites which normally are lipidated. In a further series of experiments, lipidated Ras proteins which carry a fluorescent Mant group incorporated into the farnesyl-type modification were synthesized.1251... 

Figure 11.4 Total ion current (TIC) chromatogram of lipid residue extracted from a potsherd of Early Neolithic date (Ecsegfalva, Hungary). Cx y F refer to fatty acids with carbon number (x) and number of unsaturations (y). Cx T refer to triacylglycerols with number of carbon atoms (x). P = plasticizer contamination. (Craig et al., 2007, 354 Figure 18.1, by permission.)...

Evershed, R.P. and Charters, S. (1995). Interpreting lipid residues in archaeological ceramics preliminary results from laboratory simulations of vessel use and burial. Materials Research Society Symposia Proceedings 352 85-95. 

The potential for the preservation of lipids is relatively high since by definition they are hydrophobic and not susceptible to hydrolysis by water, unlike most amino acids and DNA. A wide range of fatty acids, sterols, acylglycerols, and wax esters have been identified in visible surface debris on pottery fragments or as residues absorbed into the permeable ceramic matrix. Isolation of lipids from these matrices is achieved by solvent extraction of powdered samples and analysis is often by the powerful and sensitive technique of combined gas chromatography-mass spectrometry (GC-MS see Section 8.4). This approach has been successfully used for the identification of ancient lipid residues, contributing to the study of artifact... 

Bonfield, K. M. (1997). The Analysis and Interpretation of Lipid Residues Associated with Prehistoric Pottery pitfalls and potential. Unpublished Ph.D. thesis, University of Bradford, UK. 

Aloc-protecting group strategy. Utilizing this pathway a number of N-Ras derivatives containing natural and non-natural lipid residues were produced and the technique was extended also allowing the synthesis of fluorescent derivatives. 

Figure 3 Molecular relaxivities of liposomes with different Gd-containing membranotropic chelators. Liposomes (egg lecithin cholesterol chelator = 72 25 3) were prepared by consecutive extrusion of lipid suspension in HEPES buffered saline, pH 7.4, through the set of polycarbonate filters with pore size of 0.6, 0.4, and 0.2 mm. Liposome final size was between 205 and 225 nm. Gd content determination was performed by Galbraith Laboratories, Inc. The relaxation parameters of all preparations were measured at room temperature using a 5-MHz RADX nuclear magnetic resonance proton spin analyzer. The relaxivity of liposomes with polymeric chelators is noticeably greater because of the larger number of Gd atoms bound to a single lipid residue [16].

Two complementary experiments show that the orientation and hiding of one or the other face of the steroid ring of cholate can occur when mixtures of lecithin and bile salt are considered. One of these experiments was performed by Etienne (4), who observed the following facts incidentally while extracting lipids from the serum lipoproteins by Delsal s method. This method utilizes a mixture of methanol and methylal (1 to 4) in the cold. The proteins are precipitated, while the lipids are dissolved in the methanol-methylal solvent mixture. If this solution of the lipids is evaporated, the residue is soluble in nonpolar solvents, such as chloroform. However, if sodium cholate is added to the lipoproteins before their extraction, the residue obtained after the methylal-methanol solvent evaporates is insoluble in chloroform. More precisely, while cholesterol and the triglycerides of the lipidic residue are extracted by chloroform, all of the lecithin remains insoluble, associated to the bile salt. The explanation is probably as follows. During evaporation, methylal with its low boiling point (44°C.), evaporates first, and the solvent becomes more and more concentrated with methanol and the residual water from the lipoprotein aqueous solution. Therefore, in the lecithin plus... 

They prevent polyvalent metal ions from combining with various soils, such as lipid residues and clays, to form less dispersible residues, which adhere tenaciously to the surface to be cleaned. 

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