scholarly journals Studies on the photolytic breakdown of hydroperoxides and peroxidized fatty acids by using electron spin resonance spectroscopy. Spin trapping of alkoxyl and peroxyl radicals in organic solvents

1986 ◽  
Vol 240 (3) ◽  
pp. 789-795 ◽  
Author(s):  
M J Davies ◽  
T F Slater
Keyword(s):  
Fatty Acids ◽  
Spin Trap ◽  
Hydrogen Abstraction ◽  
Spin Trapping ◽  
Ring Closure ◽  
Peroxyl Radicals ◽  
Resonance Spectroscopy ◽  
Oxygen Oxygen ◽  
Low Levels ◽  
Trap Radical

Spin trapping using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) has been used to detect and distinguish between the carbon-centred, alkoxyl, and peroxyl radicals produced during the photolytic decomposition of hydroperoxides. Photolysis of tert-butyl and cumene hydroperoxides, and peroxidized fatty acids, in toluene, with low levels of u.v. light, is shown to lead to the initial production of alkoxyl radicals by homolysis of the oxygen-oxygen bond. Subsequent reaction of these radicals with excess hydroperoxide leads, by hydrogen abstraction, to the production of peroxyl radicals that can be detected as their corresponding adducts with the spin trap. Subsequent breakdown of these adducts produces alkoxyl radicals and a further species that is believed to be the oxidized spin-trap radical 5,5-dimethyl-1-pyrrolidone-2-oxyl. No evidence was obtained at low hydroperoxide concentrations, with either the cumene or lipid alkoxyl radicals, for the occurrence of beta-scission reactions; the production of low levels of carbon-centred radicals is believed to be due to the alternative reactions of hydrogen abstraction, ring closure, and/or 1,2 hydrogen shifts. Analogous experiments with 3,3,5,5-tetramethyl-1-pyrroline N-oxide (TMPO) led only to the trapping of alkoxyl radicals with no evidence for peroxyl radical adducts, this is presumably due to a decreased rate of radical addition because of increased steric hindrance.

Lyoluminescence and spin trapping

1982 ◽  
Vol 60 (12) ◽  
pp. 1549-1559 ◽  
Author(s):  
Kamil V Ettinger ◽  
Alexander R Forrester ◽  
Charles H Hunter
Keyword(s):  
Spin Trap ◽  
Light Yield ◽  
Spin Trapping ◽  
Water Soluble ◽  
Peroxyl Radicals ◽  
Nitroso Compounds ◽  
Γ Irradiation ◽  
Alkyl Radicals ◽  
Emitting Species ◽  
Aromatic Nitroso Compounds

The chemical origin of lyoluminescence has been probed using spin trapping techniques. Radicals derived from amino acids and saccharides by γ-irradiation in the solid state have been identified after trapping with aliphatic and aromatic nitroso compounds. Most of the radicals trapped were secondary alkyl radicals. Reaction of peroxyl radicals derived therefrom are thought to produce the emitting species (excited carbonyl compound and/or singlet oxygen). The effect which thermal annealing of the solids after γ-irradiation has on (a) the concentration of radicals in the solid, (b) the concentration of trapped radicals, and (c) the light yield has been investigated. One new water-soluble spin trap has been prepared.

scholarly journals Formation of peroxide- and globin-derived radicals from the reaction of methaemoglobin and metmyoglobin with t-butyl hydroperoxide: an ESR spin-trapping investigation

1997 ◽  
Vol 322 (2) ◽  
pp. 633-639 ◽  
Author(s):  
Jolanda Van der ZEE
Keyword(s):  
Spin Trap ◽  
Hydrogen Abstraction ◽  
Spin Trapping ◽  
Tyrosyl Radical ◽  
Alkoxyl Radical ◽  
Butyl Hydroperoxide ◽  
Heterolytic Cleavage ◽  
Esr Spin Trapping ◽  
Radical Adduct ◽  
Protein Radicals

The reaction of human methaemoglobin and horse metmyoglobin with t-butyl hydroperoxide (t-BuOOH) was investigated with the ESR spin-trapping technique. With the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) the formation of peroxyl, alkoxyl and methyl radicals derived from t-BuOOH could be detected. The relative contributions of these radicals were determined at various DMPO concentrations by computer simulation. From these data it could be concluded that the alkoxyl radical was the initial radical produced, which indicates that the hydroperoxide is cleaved homolytically. Further investigations, with the nitroso spin trap 2-methyl-2-nitrosopropane (MNP), showed the formation of globin-centred radicals. Non-specific proteolysis of the MNP adducts revealed isotropic three-line spectra, which means that the radical adducts were centred on a tertiary carbon with no bonds to a hydrogen or nitrogen. Comparison with MNP adducts of several amino acids indicated that in methaemoglobin the radical adduct was most probably located on a valine residue. With metmyoglobin the same adduct was obtained, whereas an additional adduct could be assigned to a tyrosyl radical. These protein radicals most probably resulted from hydrogen abstraction by the metal–oxo species, formed by heterolytic cleavage of the hydroperoxide. These results therefore show that homolytic cleavage of the hydroperoxide leads to the formation of peroxide-derived radicals, whereas concurrent heterolytic cleavage results in protein-derived radicals.

scholarly journals Studies on the metal-ion and lipoxygenase-catalysed breakdown of hydroperoxides using electron-spin-resonance spectroscopy

1987 ◽  
Vol 245 (1) ◽  
pp. 167-173 ◽  
Author(s):  
M J Davies ◽  
T F Slater
Keyword(s):  
Metal Ion ◽  
Spin Trap ◽  
Cumene Hydroperoxide ◽  
Initial Step ◽  
Peroxyl Radicals ◽  
Resonance Spectroscopy ◽  
Alkoxy Radical ◽  
Alkoxyl Radical ◽  
Radical Adduct ◽  
Chemical Studies

The breakdown of cumene hydroperoxide and peroxidized fatty acids by iron is shown, by use of the spin trap 5,5-dimethyl-l-pyrroline-N-oxide, to be sensitive to (a) the oxidation state of the metal and (b) the nature of the chelating ligands. The initial step in the Fe2+-catalysed breakdown is the production of an alkoxyl radical by one-electron reduction, and this type of radical has been successfully trapped from each substrate. Subsequent reactions of this alkoxyl species produce both carbon-centred and peroxyl radicals, depending on the concentrations of the reagents present. The use of the same spin trap in microsomal systems undergoing either NADPH-supported or Fe2+-induced peroxidation led to the detection of low concentrations of radical adducts, among which are signals that are believed to be due to lipid alkoxyl radicals. Reaction of polyunsaturated fatty acid hydroperoxides with both Fe2+ and lipoxygenase under anaerobic conditions gives rise to signals not only from the alkoxy-radical adduct, but also from a further species which is tentatively identified as being due to an acyl [RC(O).]-radical adduct; chemical studies lend support to this assignment.

scholarly journals Occurrence of Cis-11,12-Methylene-Hexadecanoic Acid in the Red Alga Solieria pacifica (Yamada) Yoshida

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2286
Author(s):  
Gwang-Woo Kim ◽  
Jae-Man Sim ◽  
Yutaka Itabashi ◽  
Min-Jeong Jung ◽  
Joon-Young Jun
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Red Alga ◽  
Proton Nuclear Magnetic Resonance ◽  
Animal Origin ◽  
Monoenoic Acid ◽  
Resonance Spectroscopy ◽  
Hexadecenoic Acid ◽  
Cyclopropane Fatty Acid ◽  
Hexadecanoic Acid

Fatty acids in marine algae have attracted the attention of natural chemists because of their biological activity. The fatty acid compositions of the Solieriaceae families (Rhodophyceae, Gaigartinales) provide interesting information that unusual cyclic fatty acids have been occasionally found. A survey was conducted to profile the characteristic fatty acid composition of the red alga Solieria pacifica (Yamada) Yoshida using gas chromatography-mass spectrometry (GC-MS), infrared spectroscopy (IR), and proton nuclear magnetic resonance spectroscopy (1H-NMR). In S. pacifica, two cyclopentyl fatty acids, 11-cyclopentylundecanoic acid (7.0%), and 13-cyclopentyltridecanoic acid (4.9%), and a cyclopropane fatty acid, cis-11,12-methylene-hexadecanoic acid (7.9%) contributed significantly to the overall fatty acid profile. In particular, this cyclopropane fatty acid has been primarily found in bacteria, rumen microorganisms or foods of animal origin, and has not previously been found in any other algae. In addition, this alga contains a significant amount of the monoenoic acid cis-11-hexadecenoic acid (9.0%). Therefore, cis-11,12-methylene-hexadecanoic acid in S. pacifica was likely produced by methylene addition to cis-11-hexadecenoic acid.

Further studies on the effects of dietary cottonseed oil on milk-fat secretion in the cow

1968 ◽  
Vol 35 (3) ◽  
pp. 343-352 ◽  
Author(s):  
W. Steele ◽  
J. H. Moore
Keyword(s):  
Fatty Acids ◽  
Milk Fat ◽  
Volatile Fatty Acids ◽  
Octadecenoic Acid ◽  
Cottonseed Oil ◽  
Rumen Fermentation ◽  
Total Volatile ◽  
Feeding Experiments ◽  
Concentrate Mixture ◽  
Low Levels

SummaryThe effects of the isocaloric replacement of part of the dietary concentrate mixture by cottonseed oil on the yield and composition of the milk fat and on the pattern of rumen fermentation was investigated in 2 feeding experiments with a total of 8 cows in mid-lactation. The concentrate mixtures were given with high- or low-roughage diets that supplied 9·1 or 1·8 kg of hay/day.In expt 1 the yield of milk fat was not altered by the addition of 10% cottonseed oil to the concentrate mixtures given either with the high- or with the low-levels of dietary roughage. On the low-roughage treatment, dietary cottonseed oil increased milk yield but reduced the fat content of the milk. The change from the high- to the low-roughage diets containing no cottonseed oil resulted in reductions in the yield and percentage of fat in the milk. In expt 2 the yields of milk and milk fat were similar irrespective of whether the concentrate mixture contained 5 or 10% cottonseed oil.In expt 1 the inclusion of 10% cottonseed oil in the concentrate mixture reduced the yields and percentages of the medium-chain fatty acids (12:0, 14:0 and 16:0) and increased the yields and percentages of the C18 fatty acids in the milk fat. In expt 2, when the concentrate mixture contained 5% cottonseed oil, the yields and percentages of all the fatty acids in the milk fat were similar to the values obtained when the concentrates contained 10% cottonseed oil. For any given concentrate mixture, the change from the high- to the low-roughage treatments in both expts 1 and 2 resulted in increases in the percentage of oleic acid in the milk fat. The highest concentration of trans-octadecenoic acid was observed in the milk fat of the cows when they were given the high-roughage diet with the concentrate mixture containing 10% cottonseed oil.In expt 2 the level of cottonseed oil in the concentrate mixture did not influence the pattern of rumen fermentation as measured by the concentrations of the various volatile fatty acids in the rumen liquor. However, the change from the high- to the low-roughage diets reduced the proportion of acetic and increased the proportions of propionic and n-valeric acids in the total volatile fatty acids in the rumen liquor.

Comparative analysis of the fatty acid composition of deep-water Baikal amphipods

Crustaceana ◽  
2019 ◽  
Vol 92 (1) ◽  
pp. 57-72
Author(s):  
Selmeg V. Bazarsadueva ◽  
Larisa D. Radnaeva ◽  
Arnold K. Tulokhonov
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Lake Baikal ◽  
Deep Water ◽  
Monounsaturated Fatty Acids ◽  
Manned Submersible ◽  
Main Fatty Acid ◽  
Low Levels

Abstract In this report, we have compared the fatty acid composition of the endemic Lake Baikal amphipods Ommatogammarus albinus (Dybowsky, 1874) and Parapallasea lagowskii (Dybowsky, 1874). Specimens were sampled using the deep-water manned submersible “Mir” at the oil-methane seeps of Cape Gorevoy Utes and at a hydrothermal vent in Frolikha Bay. High levels of monounsaturated fatty acids and relatively low levels of saturated and polyunsaturated fatty acids were detected in the studied amphipods, with oleic and palmitic acid representing the main fatty acid components. The habitat of the amphipods exerted a profound effect on their fatty acid profile: the amphipods of Gorevoy Utes contained higher levels of linolenic 18:3n3 and arachidonic 20:4n6 acids, while the amphipods of Frolikha Bay contained higher levels of eicosapentaenoic 20:5n3 and docosahexaenoic 22:6n3 acid. Based on these findings, we suggest that the amphipods’ diet in different areas of Lake Baikal determines their fatty acid composition.

Early-onset coronary atherosclerosis in patients with low levels of omega-3 fatty acids

2020 ◽  
Vol 74 (4) ◽  
pp. 651-656 ◽  
Author(s):  
D. O. Bittner ◽  
M. Goeller ◽  
Y. Zopf ◽  
S. Achenbach ◽  
M. Marwan
Keyword(s):  
Fatty Acids ◽  
Early Onset ◽  
Coronary Atherosclerosis ◽  
Omega 3 Fatty Acids ◽  
Omega 3 ◽  
Low Levels

THE EFFECTS OF SOME DIETARY DERIVED LIPIDS AND FAT SOLUBLE VITAMINS ON RAT SERUM TRIBUTYRINASE AND ALKALINE PHOSPHATASE

1952 ◽  
Vol 30 (4) ◽  
pp. 308-313
Author(s):  
Jack D. Taylor ◽  
Neil B. Madsen ◽  
Jules Tuba
Keyword(s):  
Fatty Acids ◽  
Alkaline Phosphatase ◽  
Oleic Acid ◽  
Stearic Acid ◽  
Serum Alkaline Phosphatase ◽  
Adult Rats ◽  
Rat Serum ◽  
Low Levels ◽  
Fat Soluble Vitamins ◽  
Increased Activity

Synthetic diets were fed to adult rats for four weeks to determine the effects of dietary stearic acid, oleic acid, glycerol, Crisco, and vitamins, A, D, and E on the activity of serum alkaline phosphatase and serum tributyrinase. On a diet devoid of fats or fatty acids, the rats manifested abnormally low enzyme levels, which for serum alkaline phosphatase fell to values characteristic of starvation. Basal levels of the two enzymes, obtained with a fat free diet, were not altered by the ingestion of glycerol or vitamins A, D, and E. Dietary stearic acid, oleic acid, and Crisco, each significantly increased activity of phosphatase and tributyrinase and it would appear that both enzymes are concerned with intestinal absorption of fatty acids. The effect of oleic acid was most pronounced with both enzymes. The rats all gained weight during the tests so none of the variations in enzyme levels can be attributed to inanition. After the dietary test periods, all groups were starved for one week. Serum phosphatase values fell to the same constant low levels for all animals. Tributyrinase values rose towards levels which suggest that the enzyme is concerned with mobilization of depot fats during periods of fasting.

Control of Fatty Acid and Lipid Biosynthesis in Euglena gracilis by Ammonia, Light and DCMU

1972 ◽  
Vol 27 (1) ◽  
pp. 53-61 ◽  
Author(s):  
P. Pohl ◽  
H. Wagner
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
White Light ◽  
Euglena Gracilis ◽  
Fatty Acid Biosynthesis ◽  
Neutral Lipids ◽  
Fluorescent Light ◽  
Low Levels ◽  
High Concentrations ◽  
Monogalactosyl Diglyceride

When Euglena gracilis was grown under white (fluorescent) light in media containing high concentrations of ammonium chloride (more than 0.005%), the main lipids synthesized were monogalactosyl diglyceride, digalactosyl diglyceride, phosphatidyl glycerol, sulfolipid and the all cis △7,10-16:2, △7,10,13-16:3, △4,7,10,13-16:4, △9,12-18:2 and △9,12,15-18:3 fatty acids. At low levels of ammonium (less than 0.002%) these compounds were produced only in small amounts, while neutral lipids, phosphatidyl choline, phosphatidyl ethanolamine and the 14:0, 16:0 and 16:1 fatty acids predominated.When Euglena gracilis was grown in white light in the presence of dichlorophenyldimethylurea (DCMU) or in the dark, fatty acid and lipid biosyntheses followed the same pattern as in white light at low levels of ammonium. Similar results were obtained when nitrate served as the only nitrogen source in the light and in the dark.The results indicate that in Euglena gracilis there are a light independent and a light and ammonium dependent pathway of fatty acid biosynthesis. Both pathways seem to be in association with specific lipids.

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