Document Detail

Effects of conjugated linoleic acid on oxygen diffusion-concentration product and depletion in membranes by using electron spin resonance spin-label oximetry.
MedLine Citation:
PMID:  10580328     Owner:  NLM     Status:  MEDLINE    
The effect of conjugated linoleic acid (CLA) on the relation between structure and function of membranes is described in this paper. Electron spin resonance (ESR) spin-label oximetry was used in the present study to evaluate if oxygen transport and oxygen depletion were affected by incorporation of CLA instead of linoleic acid into membrane phospholipids. Specifically, 1-stearoyl-2-(9cis, 11 trans-octadecadienoyl)-phosphorylcholine (SCLAPC) was incorporated into soy plant phosphatidylcholine (soy PC) or egg yolk PC (EYPC) bilayers. The use of spin labels attached to different carbons along the fatty acid chain makes it possible to carry out structural and oximetric determinations with the same test sample. For example, the incorporation of 5 mol% SCLAPC increased the oxygen diffusion-concentration product in soy PC or EYPC liposomes at 37 degrees C, slightly decreased the ordering of the hydrocarbon chains at the C10 and C12 positions (in the region of the conjugated double bonds), and increased the rate of oxygen depletion from the aqueous medium. Similar results were not obtained by incorporating 5 mol% of 1-stearoyl-2-linoleoyl-PC (SLPC). In our model system, free-radical generation was initiated by extended incubation of the liposomes, by induction by 2,2'-azobis(2-amidinopropane)hydrochloride, or by ultraviolet irradiation of H2O2. The rate of consumption of molecular oxygen was studied by monitoring the oxygen concentration in the aqueous phases of the liposomes. The effect of 5 mol% SCLAPC in soy PC was significantly larger than 5 mol% SLPC in soy PC; the response patterns with soy PC and EYPC were similar. Furthermore, 5 mol% SCLAPC in 1-palmitoyl-2-linoleoyl-PC showed similar oxygen consumption to that observed with 5 mol% SCLAPC in EYPC. On the other hand, 5 mol% SCLAPC in synthetic PC membranes containing saturated or monounsaturated fatty acids showed low oxygen depletion rates. The perturbation of membrane structure and the increase of the relative oxygen diffusion-concentration products provided a potential mechanism by which CLA incorporated into membrane lipids could affect oxidative stress.
J J Yin; M M Mossoba; J K Kramer; M P Yurawecz; K Eulitz; K M Morehouse; Y Ku
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Lipids     Volume:  34     ISSN:  0024-4201     ISO Abbreviation:  Lipids     Publication Date:  1999 Oct 
Date Detail:
Created Date:  1999-12-27     Completed Date:  1999-12-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0060450     Medline TA:  Lipids     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1017-23     Citation Subset:  IM    
US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Washington DC 20204, USA.
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MeSH Terms
Electron Spin Resonance Spectroscopy
Linoleic Acid / chemistry,  metabolism*
Membranes, Artificial*
Oxygen / chemistry,  metabolism*
Spin Labels
Reg. No./Substance:
0/Membranes, Artificial; 0/Spin Labels; 2197-37-7/Linoleic Acid; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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