Detection of lipids

Nonspecific Reagents Used for the Detection of Lipids onTLC Plates or Sheets... 

Microbes of differing physiologic types, acting in consortia, appear to be more destructive than monocultures. Methods for examining consortia are based on the detection of lipid biomarkers that are characteristic for different classes of microbes. These can be analyzed by gas chromatography coupled with mass spectrometry [512]. 

Kawasaki, K., J.-J. Yin, W. K. Subczynski, J. S. Hyde, and A. Kusumi. 2001. Pulse EPR detection of lipid exchange between protein-rich raft and bulk domains in the membrane Methodology development and its application to studies of influenza viral membrane. Biophys. J. 80 738-748. 

Recknagel, R.O. and Glende, E.A. (1984). Spectrophotometric detection of lipid conjugated dienes. Methods in Enzymology 105 331-337. 

Nourooz-Zadeh J. 1999. Ferrous ion oxidation in presence of xylenol orange for detection of lipid hydroperoxides in plasma. Methods Enzymol 300 58-62. 

Surface Sensing Experiment Detection of Lipid Membrane and Membrane Proteins... 

Lipid Peroxidation Chemistry, 105, 273 overview of methods used for detecting lipid peroxidation, 105, 283 chemical methods for the detection of lipid hydroperoxides, 105, 293 comparative studies on different methods of malonaldehyde determination, 105, 299 concentrating ethane from breath to monitor lipid peroxidation in vivo, 105, 305. 

Cyt c is associated with the outer surface of the inner mitochondrial membrane. Phospholipids induce conformational changes in the protein and, in certain instances, the haem can convert to the high spin (S = 5/2) form, indicative of a weakening of the ligand field caused by displacement of the sixth ligand (Met-80). This has been associated with the detection of lipid radicals by direct EPR (at 11 K).65 Indeed, peroxidase-type activity is also evident in the reaction of cyt c with lipid hydroperoxides, as studied by spin trapping in conjunction with HPLC and MS.66... 

K12. Kondo, Y., Ohnishi, M., and Kawaguchi, M., Detection of lipid peroxidation catalyzed by chelated iron and measurement of antioxidant activity of wine by a chemiluminescence analyzer. J. Agric. Food Chem. 47, 1781—1785 (1999). 

Several new methodologies have been developed in recent years for the surface analysis of lipids. These methods allow direct detection of lipids from surfaces such as tissue sections and intact cells without prior extraction and thus enable the determination of spatial distribution of the lipids. There are three basic requirements for the surface analysis. The analytes of interest must be desorbed from the surface by the interaction of a sampling probe such as spray, laser, or plasma. The desorbed analytes must first be ionized and then... 

Figure 11.9 Schematic representation of the SiC>2 nanoparticles prepared by Greenway and coworkers64 for the detection of lipid peroxidation 15 nm Si02 nanoparticles covalently coated with the coumarin dye are embedded in a 100 nm silica protecting shell.

A2. Abbey, M., Savage, J. K., Macldnnon, A. M., Barter, P. J., and Calvert, G. D., Detection of lipid transfer protein activity in rabbit liver perfusate. Biochim. Biophys. Acta 793, 481-484 (1984). 

Some reagents can be impregnated into the layer before spotting of samples if the selectivity of the separation is not affected. Detection takes place only upon heating after development. This method has been used for the detection of lipids as blue spots on a yellow background on silica gel layers preimpregnated with phosphomolybdic acid. A few detection reagents (HCl, sulfuryl chloride, iodine) can be transferred uniformly to the layer as vapors in a closed chamber rather than as solutions. 

All presented studies have been performed retrospectively on patient or animal tissues with the aim of identifying molecular signals or signatures for a disease or disease status. While DESI and SIMS focus mainly on the detection of lipids, MALDI imaging can provide molecular signatures ranging from metabolites to proteins. 

Pryor W.A., Castle L., Chemical methods for the detection of lipid hydroperoxides, Meth. Enzymol., 1984,105,293-299. 

Stillwell W, Jenski LJ, Zerouga M, Dumaual AC. Detection of lipid domains in docosahexaenoic acid-rich bilayers by acyl chain-specific FRET probes. Chem Phys Lipids 2000 104 113-132. 

Makrigiorgos, G. M., Kassis, A. I., Mahmood, A., Bump, E. A., and Savvides, P. (1997) Novel fluorescein-based flow-cytometric method for detection of lipid peroxidation. Free Radic. Biol. Med. 22(1-2), 93-100. 

Makrigiorgos, G. M. (1997) Detection of lipid peroxidation on erythrocytes using the excimer- forming property of a lipophilic BODIPY fluorescent dye. J. Biochem. Biophys. Methods 35(1), 23-35. 

Another instrument called the transport detector, used for detection of lipids, proteins or carbohydrates, requires the transport of the column eluent by a moving wire disc, chain or helix. The solvent is evaporated in a furnace and the nonvolatile sample passes into a flame ionization detector (FID) which is detailed later under gas chromatography (GC) wherein FID counts amongst the major detectors. 

The concurrent detection of lipid metabolites by HPLC provides a rapid, convenient, noninvasive method for assessing oxidative tissne damage and cytotoxicity by foreign chemicals. Urine samples were collected after STE treatment over diy ice for 6.0-h time intervals on the indicated days, and the resnlts are expressed as nmol/kg body weight/6.0h. In control animals, time-dependent increases occnrred in the urinary excretion of the four lipid metabolites over the 105 days of the study. Increases of 1.9-,... 

Paradis, V., M. Kollinger, M. Fabre, A. Holstege, T. Poynard, and P. Bedossa. 1997. In situ detection of lipid peroxidation by-products in chronic liver diseases. Hepatology 26 13 5-142. 

Valentina L, Gilberto C., Marcello R., Santo S., and Eliana L. In vivo detection of lipid-based nano-and microparticles in the outermost human stratum corneum by EDX analysis. Int. J. Pharm. 447... 

ITigh-performance liquid chromatography (FIPLC) is routinely used for the compositional analysis of lipid classes, TAGs, and tocopherols. Flowever, there can be problems for the quantitative detection of lipids other than tocopherols because most lipids do not have a suitable chromaphore, and therefore cannot be detected spectrophotometrically. Evaporative technology such as nebulizing mass detectors and the quartz/flame ionization transport system has to be employed. 

Detection. Detection of lipids separated by open tubular SFC has been by flame ionization or mass spectrometry. For packed columns, ultraviolet (UV) or detectors or ELSDs have been employed. ELSDs have been used extensively for detection of lipids in connection with HPLC, and it is of interest to apply this detector also to packed column SFC. 

The mobile phase consists of one or more solvents that are pumped through the chromatographic system, resulting in the separation of analytes. Mobile phases may also contain modifiers. Examples of frequently used solvents include hexane, methanol, 2-propanol, acetonitrile (ACN), and water. Examples of modifiers include tri-fluoroacetic acid, acetic acid, or formic acid. In general, the composition of the mobile phase should be kept simple. Factors that influence the choice of mobile phase include the solubility of the sample in the mobile phase, the polarity of the mobile phase, ultraviolet absorption wavelength, refractive index, and viscosity of the solvents. The purity of the solvents in the mobile phase is also important because the region of UV that is used for the detection of lipids (200-215 nm) must be free of interferences. For phospholipids, the most popular solvent systems are transparent to UV in the range of 200-215 nm they include... 

P. Moreno, R. Lodder, K. Purushothaman, et al.. Detection of Lipid Pool, Thin Fibrous Cap, and Inflammatory Cells in Human Aortic Atherosclerotic Plaques by Near-Infrared Spectroscopy, Circulation, 105, 923 (2002). 

Fig. 10.10. Composition of organic soivents (methanoi) in the matrix soiution influences signal detection of lipids and peptides. Matrix solutions (containing 35 mg/ml DHB and 0.1 % TF/ of different ratios of water and methanol were prepared. Next, 0.5 p,l of each solution was applied to the section of mouse brain homogenate, which has homogeneous molecular distribution at any location of the section (n = 3). By increasing the methanol concentration, crystal form was also changed needle-like crystal, from which peptides were detected, was changed to the aggregate of smaller crystals from which lipids were detected.

Olivares A, Dryahina K, Spanel R Rapid detection of lipid oxidation in beef muscle packed under modified atmosphere by measuring volatile organic compounds using SIFT-MS. Food Chem. 2012 135 1801-8. 

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