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A Biophysical View on the Function and Activity of Endotoxins
Published in Helmut Brade, Steven M. Opal, Stefanie N. Vogel, David C. Morrison, Endotoxin in Health and Disease, 2020
Ulrich Seydel, Andre Wiese, Andra B. Schromm, Klaus Brandenburg
Emmerling et al. (4-dodecyl dimethylammonium-1-oxyl-6-tetramethylpiperidine bromide) labeling the headgroup region was greater in the long-chain than in the short-chain fraction by the tightly packed sugar portion of the latter. Furthermore, the addition of cations led to a stronger displacement of the spin probe in the case of the short-chain fraction. These results indicate that the aggregate shape and reactivity of LPS are affected by O-antigen length.
Role of Tumor Cell Membrane in Hyperthermia
Published in Leopold J. Anghileri, Jacques Robert, Hyperthermia In Cancer Treatment, 2019
The use of an electron spin probe has shown increased orderliness in multilayers of a model system composed of brain white-matter lipids when treated with low concentrations of tetracaine, but treatment with larger concentrations resulted in disorder.206 At concentrations which affect the physical state of membranes very little, local anesthetics destabilize the cytoskeletal system of microtubules and microfilaments.207 This effect seems to take place through calcium ion displacement by anesthetics208 in a fashion similar to their effects corresponding to calcium-dependent enzymes.209 Since microtubules and microfilaments are very important in maintaining membrane stability,208 their weakening by local anesthetics interaction may decrease membrane integrity and support.
Enzymes
Published in Stephen W. Carmichael, Susan L. Stoddard, The Adrenal Medulla 1986 - 1988, 2017
Stephen W. Carmichael, Susan L. Stoddard
In an accompanying article, Wakefield, Cass and Radda (1986b) described an experimental system using hydrated nickel ion as a membrane-impermeable spin probe to selectively eliminate the electron paramagnetic resonance signal of extravesicular ascorbate free radical, thereby allowing distinction between ascorbate free radical inside and outside closed vesicles. Using this method, they found that ascorbate free radical inside the chromaffin vesicle indeed can be reduced by the action of the NADH:ascorbate free radical oxidoreductase on the topologically distant mitochondrion.
Concentration dependence of nitroxyl spin probes in liposomal solution: electron spin resonance and overhauser-enhanced magnetic resonance studies
Published in Journal of Liposome Research, 2018
V. Meenakumari, Hideo Utsumi, A. Jawahar, A. Milton Franklin Benial
Several spectroscopic tools have been used in the past to investigate the microstructure of biological membranes (Bayerl et al., 1986; Ribosa et al., 1992; Schubert et al., 1986). Electron spin resonance (ESR) has proved to be a powerful method for monitoring the biological characteristics of plasma membranes, their interactions with spin-labeled compounds and the dynamics of the latter. The fine structure of the ESR spectra provides information on the dynamics, polarity, pH, structural and redox properties of the environment of the spin-labeled molecule (Hemminga & Berliner, 2007). The spin probe ESR technique has extensively been used for studying model and biological membranes (Dalton, 1984; Grammenos et al., 2009) because spin probes are sensitive and informative monitors of their environment. Membrane studies by ESR are based on the use of a versatile nitroxide probe. Nitroxides are stable free radicals having ESR spectra sensitive to the molecular microenvironment. Several reviews have described the theory of nitroxide ESR spectral analysis and applications of nitroxides for membrane studies. ESR is also used to investigate the dynamics of nitroxyl radicals in phosphatidylcholine based lipid membranes (Fedotov et al., 1998; Marsh, 2007). 3-Methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl (MC-PROXYL) is one of the aminoxyl radicals, which distributes to brain region for investigation of redox-status and free radical reaction in brain diseases (Lurie & Mader, 2002). MC-PROXYL is suitable spin probe for the study of free radical reaction in the brain by in vivo ESR detection. MC-PROXYL is more lipophilic with high permeability of BBB (blood–brain barrier) and in cell. Recently some biologically important membrane protein systems studied by ESR spectroscopy (Sahu et al., 2015; Li et al., 2014: Yu et al., 2015).