scholarly journals Identification of novel neutrophil very long chain plasmalogen molecular species and their myeloperoxidase mediated oxidation products in human sepsis

Redox Biology ◽  
2021 ◽  
Vol 48 ◽  
pp. 102208
Author(s):  
Kaushalya Amunugama ◽  
Matthew J. Jellinek ◽  
Megan P. Kilroy ◽  
Carolyn J. Albert ◽  
Valerio Rasi ◽  
...  
Keyword(s):  
Molecular Species ◽  
Oxidation Products ◽  
Human Sepsis ◽  
Mediated Oxidation ◽  
Long Chain

scholarly journals The occurrence of polyenoic very long chain fatty acids with greater than 32 carbon atoms in molecular species of phosphatidylcholine in normal and peroxisome-deficient (Zellweger's syndrome) brain

1988 ◽  
Vol 253 (3) ◽  
pp. 645-650 ◽  
Author(s):  
A Poulos ◽  
P Sharp ◽  
D Johnson ◽  
C Easton
Keyword(s):  
Fatty Acids ◽  
Molecular Species ◽  
Carbon Chain ◽  
Normal Brain ◽  
Long Chain Fatty Acids ◽  
Brain Physiology ◽  
Chain Lengths ◽  
The Brain ◽  
Long Chain ◽  
Chain Fatty Acids

The n-6 tetra- and pentaenoic fatty acids with carbon chain lengths greater than 32 found in normal brain are located predominantly in a separable species of phosphatidylcholine. A similar phospholipid is found in increased amounts in the brain of peroxisome-deficient (Zellweger's syndrome) patients, but the fatty acid composition differs in that penta- and hexaenoic derivatives predominate. Our data strongly suggest that the polyenoic very long chain fatty acids are confined to the sn-1 position of the glycerol moiety, while the sn-2 position is enriched in saturated, monounsaturated and polyunsaturated fatty acids with less than 24 carbon atoms. It is postulated that these unusual molecular species of phosphatidylcholine may play some, as yet undefined, role in brain physiology.

Behavior of Rubber Hydrocarbon in a Molecular Still

1939 ◽  
Vol 12 (4) ◽  
pp. 789-793 ◽  
Author(s):  
W. Harold Smith ◽  
Henry J. Wing
Keyword(s):  
Molecular Weight ◽  
Vapor Pressure ◽  
High Molecular Weight ◽  
Molecular Species ◽  
Decomposition Temperature ◽  
Sedimentation Equilibrium ◽  
Chain Molecules ◽  
Molecular Weights ◽  
Average Value ◽  
Long Chain

Abstract Some investigators believe that rubber consists of associated molecules, and others accept Staudinger's view that long-chain molecules are formed by polymerization. Pummerer, Andriessen and Gündel have obtained a molecular weight as low as 600. Meyer and Mark believe that it is approximately 5,000, although they calculated on the basis of osmotic pressures values as high as 350,000. They, as well as Pummerer, consider that rubber is an associated colloid and that high molecular weights are caused by aggregates, sometimes called micelles. Staudinger, however, considers that the long-chain rubber molecule itself has a molecular weight of 200,000 or even 350,000, and that products with lower values, which may be formed in rubber, result from degradation. if the molecules are small it might be possible to distil them if their vapor pressure could be sufficiently increased, but none would distil without decomposition if the molecules are very large. Because the vapor pressure of rubber below its decomposition temperature is low, it appeared of interest to attempt to distil the material in a molecular still. Paraffin wax and sugar, both substances of relatively high molecular weight, have been successfully distilled in this type of apparatus. Subsequent to the work described in this paper, the molecular weight of sol rubber prepared at this Bureau was determined by Kraemer and Lansing of E. I. du Pont de Nemours & Co., Inc. They used the Svedberg method of sedimentation equilibrium in an ultracentrifuge with ethereal solutions of sol rubber. The temperature of the solutions during determinations was approximately 10° C, and an average value of 460,000 was obtained. There was evidenced of a mixture of molecular species.

scholarly journals Unique molecular species of phosphatidylcholine containing very-long-chain (C24-C38) polyenoic fatty acids in rat brain

1990 ◽  
Vol 265 (3) ◽  
pp. 763-767 ◽  
Author(s):  
B S Robinson ◽  
D W Johnson ◽  
A Poulos
Keyword(s):  
Fatty Acids ◽  
Rat Brain ◽  
Molecular Species ◽  
Carbon Chain ◽  
Neonatal Rat ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Chain Lengths ◽  
Neonatal Rat Brain ◽  
Long Chain

Rat brain has been shown to contain polyenoic very-long-chain fatty acids (VLCFA) belonging to the n-3 and n-6 series with four, five and six double bonds and even-carbon chain lengths from 24 to 38. These fatty acids are almost exclusively located in unusual molecular species of phosphatidylcholine at the sn-1 position of the glycerol backbone, whereas saturated, monoenoic and polyenoic fatty acids with less than 24 carbon atoms are present at the sn-2 position. Polyenoic VLCFA phosphatidylcholine in neonatal rat brain is enriched with n-6 pentaenoic and n-3 hexaenoic VLCFA with up to 36 carbon atoms, whereas the corresponding phospholipid in adult rat brain mainly contains n-6 tetraenoic and n-3 pentaenoic VLCFA with up to 38 carbon atoms. The total amount of polyenoic VLCFA associated with phosphatidylcholine is highest in the brain of immature animals. Polyenoic VLCFA phosphatidylcholine appears to be predominantly confined to nervous tissue in rats, and it is envisaged that this phospholipid is of physiological significance.

Identification and Formation Pathway of Laccase-Mediated Oxidation Products Formed from Hydroxyphenylureas

2006 ◽  
Vol 54 (14) ◽  
pp. 5046-5054 ◽  
Author(s):  
C. Jolivalt ◽  
L. Neuville ◽  
F. D. Boyer ◽  
L. Kerhoas ◽  
C. Mougin
Keyword(s):  
Oxidation Products ◽  
Formation Pathway ◽  
Mediated Oxidation

Multiple Erythroid Isoforms of Human Long-Chain acyl-CoA Synthetases Are Produced by a Switch of the Fatty Acid Gate-Domains.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1672-1672
Author(s):  
Eric Soupene ◽  
Frans A. Kuypers
Keyword(s):  
Plasma Membrane ◽  
Fatty Acid ◽  
Substrate Specificity ◽  
Species Composition ◽  
Molecular Species ◽  
Molecular Species Composition ◽  
Phospholipid Molecular Species ◽  
Chain Acyl ◽  
Long Chain ◽  
Plasma Membrane Phospholipid

Abstract In mammals, long-chain acyl-CoA synthetases (ACSL) are necessary for fatty acid degradation, phospholipid remodeling, and production of long acyl-CoA esters that regulate various physiological processes. These enzymes play a crucial role in plasma membrane phospholipid turnover in erythrocytes, maintaining the complex phospholipid molecular species composition essential for proper membrane function. The mechanism by which this highly dynamic turnover together with an ever-changing plasma fatty acid pool maintains phospholipid composition is poorly understood. We have previously cloned Acyl-CoA Synthetase Long-chain member 6 (ACSL6), the isoform responsible for activation of long-chain fatty acids in erythrocytes. Two additional transcript variants of this protein were subsequently isolated from brain and testis. We report the expression of four different variants of ACLS6 in reticulocytes, one as we originally reported, two of which are novel, one as was identified in brain cells. PCR amplifications using primers for the predicted variable regions were performed from cDNAs of CD34 positive erythroid progenitors, K562 cells, fetal blood cells, reticulocytes and placenta. ACSL variants were expressed in E. coli host BL21DE3 cells using the pET28a vector, and detected by His tag immuno detection. Sequence alignments were generated using sequences retrieved from RefSeq and GenBank databases on the NCBI site. Exon and intron definition for ACSL members were obtained using evidence viewer and model maker available at the map viewer page of each gene. We identified four different spliced variants of ACSL6 in erythroid cells based on a mutually exclusive exon pair. Each exon of this pair encodes a slightly different short motif that contains the fatty acid Gate domain, a conserved structural domain found in all vertebrate and invertebrate ACSL homologs. The motif differs in the presence of either the aromatic residue phenylalanine (Phe) or tyrosine (Tyr), and seems to play a role in substrate specificity. One of the new forms contained an exon not found in any other ACSL isoforms. Erythroid precursors also express the closely related ACSL1, and we characterized two additional isoforms of this protein, similar to ACSL6. When analyzed on denaturing SDS polyacrylamide gel both ACSL1 and 6 appeared to exist as a dimer. Based on our results, we propose the generation of two different Gate-domains by alternative splicing of the two exons in these proteins. One represents a switch of the Phe to the Tyr Gate-domain motif, the other resulted of the exclusion of both. Swapping of this motif appears to be common to all mammalian homologs of ACSL1 and 6. We conclude that the Phe to a Tyr substitution in the Gate-domain, or its removal, together with the formation of homo or heterodimers will allow ACSL6 the structural diversity to define substrate specificity that maintains the complex plasma membrane phospholipid molecular species composition in erythrocytes.

The extension to long-chain alkanes and to high temperatures of the hydroperoxide chain mechanism of autoxidation

1969 ◽  
Vol 308 (1495) ◽  
pp. 547-568 ◽  
Keyword(s):  
Carbonyl Compounds ◽  
Oxidation Products ◽  
Antioxidant Compounds ◽  
Chain Mechanism ◽  
Chemical Methods ◽  
Alkyl Radicals ◽  
Phase Oxidation ◽  
Two Factors ◽  
Alkylperoxy Radicals ◽  
Long Chain

The liquid-phase oxidation of 2-methylhexadecane has been studied to determine how adequately the hydroperoxide chain mechanism describes the oxidation of high molecular weight alkanes and to elucidate the changes in this mechanism caused by increased temperature. The reaction between 2-methylhexadecane and molecular oxygen has been studied at temperatures of 145 to 230 °C and the oxidation products analysed by gas-chromatographic and chemical methods. Over 160 products including hydroperoxides, alkanes, alcohols, carbonyl compounds and acids have been identified and the dependence of their yields on time, temperature and oxygen concentration measured. The attack on 2-methylhexadecane at temperatures throughout this range is selective, indicating that chain propagation occurs predominantly by the reaction of alkylperoxy radicals with alkane molecules followed by the addition of oxygen to the alkyl radicals so formed. At low temperatures the former reaction is rate-determining. However, an increase in temperature increases the rate of this reaction and reduces the concentration of oxygen dissolved in the alkane; the combined effect of these two factors causes the addition of oxygen to alkyl radicals to become rate-determining at temperatures above ca . 210 °C. As a result of this change, the concentration of alkyl radicals relative to that of alkylperoxy radicals increases with temperature. Consequently, both the yield of alkanes, and the fraction of secondary alkyl radicals that react with 2-methylhexadecane molecules to form more stable tertiary radicals, increase. These results help to predict the necessary properties of a high temperature antioxidant; compounds that react specifically with alkyl radicals rather than with alkylperoxy radicals should function thus.

The composition of grape cuticle wax

1965 ◽  
Vol 18 (7) ◽  
pp. 1059 ◽  
Author(s):  
F Radler ◽  
DHS Horn
Keyword(s):  
Fatty Acids ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Oleanolic Acid ◽  
Light Petroleum ◽  
Oxidation Products ◽  
Straight Chain ◽  
Neutral Alumina ◽  
Chain Lengths ◽  
Long Chain

The cuticle wax of the grape is composed of a soft wax (30%) readily removed by light petroleum and a hard wax (30%), mainly oleanolic acid, removed by chloroform. The soft wax of the fresh grape is composed chiefly of long-chain alcohols together with smaller amounts of aldehydes, esters, fatty acids, hydrocarbons, oleanolic acid, and small amounts of high molecular weight substances. The soft wax of dried grapes is similar in composition but contains no aldehydes and larger amounts of high molecular weight substances and oxidation products. The aldehydes, unusual wax components, are straight chain and range from C16 to C32 with the even chain-lengths predominating. They were destroyed by neutral alumina but can be chromatographed on silicic acid.

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