Structural characterization, tissue

The biogenic amines are the preferred substrates of MAO. The enzyme comes in two flavors, MAO-A and MAO-B, both of which, like FMO, rely on the redox properties of FAD for their oxidative machinery. The two isoforms share a sequence homology of approximately 70% (81) and are found in the outer mitochondrial membrane, but they differ in substrate selectivity and tissue distribution. In mammalian tissues MAO-A is located primarily in the placenta, gut, and liver, while MAO-B is predominant in the brain, liver, and platelets. MAO-A is selective for serotonin and norepinephrine and is selectively inhibited by the mechanism-based inhibitor clorgyline (82). MAO-B is selective for /1-phcncthylaminc and tryptamine, and it is selectively inhibited by the mechanism-based inhibitors, deprenyl and pargyline (82) (Fig. 4.32). Recently, both MAO-A (83) and MAO-B (84) were structurally characterized by x-ray crystallography. 

T ignin is one of the most abundant natural products constituting about one-fourth of the woody tissue in plants. Nature has chosen a unique synthetic technique to prepare this cross-linked polymeric material from coniferyl alcohol and related substances. The mechanism of lignin formation is not completely known yet, and the structural characterization of lignin has been only partially successful despite considerable research. 

Vibrational microspectroscopy provides a unique means for molecular level structure characterization of a variety of biological processes associated with skin. For the past several years, this laboratory has utilized Raman and IR spectroscopy, microscopy, and imaging to monitor the biophysics of the skin barrier, mechanisms of drug permeation and metabolism in intact tissue, and, more recently, the complex events that transpire during wound healing in an ex vivo skin model [1-6]. 

The following protocols can be used for the isolation and structural characterization of any natural bioactive peptides from the immune system of invertebrates. The different procedures that will be detailed below refer to the identification and primary structure determination of the Drosophila immune-induced peptides (19,20,23,27,30) and of bioactive peptides from the immune system of other Diptera (17,21,24,31). These approaches were also successfully used for the discovery of bioactive peptides from crustaceans, arachnids, and mollusks. These methods should be considered as a guideline and not as the exact procedure to follow (see Note 3). The suggested procedures will be reported following the normal order of execution, (1) induction of the immune response by an experimental infection, (2) collection of the immunocompetent cells (hemocytes), tissues (epithelia, trachea, salivary glands, etc.)... 

Jackson S, Wang H, Woods A (2007) In situ structure characterization of glycerophospholipids and sulfatides in brain tissue using MALDI-MS/MS. J Am Soc Mass Spectrom 18 17-26. doi 10.1016/j.jasms.2006.08.015... 

E-cadherin is unique in that it not only, like other cadherin family members, mediates homophilic adhesion to establish and maintain cellcell contacts, it also serves as a counter-receptor for integrins Oe/37 (Cepek et al, 1994) and (Whittard et al, 2002) in heterophilic adhesion. In fact, the interaction between E-cadherin on mucosal epithelial cells and Oe/S on intraepithelial lymphocytes has been the best characterized tissue-specific interaction for lymphocyte retention. Although structure of binding domains between E-cadherin and is not available, mutagenesis... 

The variety of MS-based approaches [see Fig. (1) and Fig. (2) for a general view of the strategies] that have been used to discover, identify and elucidate effectors of the Drosophila immune defense reactions is presently reviewed.Regardless of the approach, MS allowed the discovery and structural characterization of an unprecedented number of systemic immune effectors, as well as the detection of such effectors within tissues expressing a local immune response. 

Various EETs have been measured in tissues as well as physiological fluids such as urine (G. FitzGerald, 1990). Biologically active lipids, originally defined as an endothelium-derived hyperpolarizing factor and an inhibitor of Na /K ATPase found in the thick ascending loop of Henley cells, were structurally characterized as 1 (/ ), 2(5)-EET and 20-HETE, both derived from cytochrome P-450-mediated metabolism of AA [35]. Interestingly, the EETs can readily form CoA esters and participate in reacylation of... 

Jackson, S.N. Wang, H-Y.J. Woods, A.S. In situ structural characterization of phosphatidylcholines in brain tissue using MALDI-MS/MS. J. Am. Soc. Mass Spectrom. 2005,16, 2052-2056. 

Lesion An abnormal change in the structure of tissue or organs due to disease or injury, usually characterized by a "break" in the tissue. 

The CLA and 18 1 isomer composition in the milk and meat fat of ruminants is a mixture of numerous positional and geometric isomers, most of which are generated by specific rumen bacteria, or subsequently re-synthesized in tissues by specific enzymes. To understand their biosynthesis, with the aim of manipulating these biochemical processes, requires appropriate techniques to determine each of the individual isomers with confidence. Detailed chemical syntheses are presented in Chapter 3 to prepare appropriate standards Chapter 4 provides a summary of complementary gas-, adsorption-, and argentation-chromatographic techniques required for the analysis of all the CLA and trans- and af-18 l isomers Chapter 5 presents improved separations of the CLA isomers using modified silver ion and reverse phase HPLC techniques while Chapter 6 is devoted to a complete structural characterization of the methyl esters of CLA isomers using acetonitrile chemical ionization tandem mass spectrometry. 

Ridenour, W.B., Kliman, M., McLean, J.A., and Caprioli, R.M. (2010) Structural characterization of phospholipids and peptides directly from tissue sections by MALDl traveling-wave ion mobility-mass spectrometry. Anal. Chem., 82, 1881-1889. 

Histology Staining Use of particular staining reagents to stain tissue sections for structural characterization of cells and tissues. 

L Hereux N, Dusserre N, Konig G, Victor B, Keire P, Wight TN, et al. Human tissue engineered hlood vessels for adult arterial revascularization. Nat Med 2006 12 361-5. Donovan DL, Schmidt SP, Townshend SP, Njus GO, Sharp WV. Material and structural characterization of human saphenous vein. J Vase Surg 1990 12 531-7. 

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