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Polyunsaturated fatty acids in the psychrophilic bacterium Shewanella gelidimarina ACAM 456(T): molecular species analysis of major phospholipids and biosynthesis of eicosapentaenoic acid

Citation

Nichols, DS and Nichols, PD and Russell, NJ and Davies, NW and McMeekin, TA, Polyunsaturated fatty acids in the psychrophilic bacterium Shewanella gelidimarina ACAM 456(T): molecular species analysis of major phospholipids and biosynthesis of eicosapentaenoic acid, Biochimica et Biophysica Acta - Lipids & Lipid Metabolism, 1347, (2-3) pp. 164-176. ISSN 0005-2760 (1997) [Refereed Article]

DOI: doi:10.1016/S0005-2760(97)00068-4

Abstract

The production of eicosapentaenoic acid [20:5ω3; EPA] from Shewanella gelidimarina (ACAM 456(T)) was investigated with respect to growth temperature and growth on sole carbon sources. The percentage and quantitative yield of EPA remained relatively constant at all growth temperatures within or below the optimal growth temperature region. At higher growth temperatures, these values decreased greatly. Growth on differing sole carbon sources also influenced the percentage and amount of EPA produced, with the fatry acid composition influenced by provision of potential acyl chain primers as sole carbon sources. The highest amounts of EPA occurred from growth on propionic acid and L-leucine respectively, while the highest percentage of EPA occurred from growth on L-proline. Monounsaturated fatty acid components and EPA were concentrated in phosphatidylglycerol (PG), while the proportion of branched-chain fatty acids was elevated in phosphatidylethanolamine (PE); the two major phospholipid classes. Specific associations of EPA with other acyl chains were identified within cellular phospholipid classes. The association of EPA with 17:1 and 18:0 acyl chains in phospholipid species was specific to PG, whereas the association of EPA with i13:0/13:0 and 14:0/i14:0 was specific to PE. Such acyl chain 'tailoring' is indicative of the important role of EPA in bacterial membrane adaptive responses. EPA was also a large component (22%) of a non-esterified fatty acid (NEFA) fraction within the total lipid extract of the bacterium. This may point toward a particular role of NEFA in polyunsaturated fatty acid (PUFA) metabolism. The formation of EPA was investigated by labelling with L-[U-14 C]serine and sodium [1-14 C]acetate. The accumulation of radiolabel within unsaturated intermediates (di-, tri- and tetraunsaturated fractions) was low, indicating a rapid formation and derivatisation of these components. Similar results were found for the unsaturated fatty acid fractions of both PE and PG using sodium [1-14C]acetate radiolabel. The regulation of triunsaturated fatty acid components may be a potential control site in PUFA biosynthesis.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Biochemistry and Cell Biology
Research Field:Analytical Biochemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Environmental Sciences
Author:Nichols, DS (Dr David Nichols)
Author:Nichols, PD (Dr Peter Nichols)
Author:Davies, NW (Associate Professor Noel Davies)
Author:McMeekin, TA (Professor Thomas McMeekin)
ID Code:10407
Year Published:1997
Web of Science® Times Cited:27
Deposited By:Agricultural Science
Deposited On:1997-08-01
Last Modified:2011-08-11
Downloads:0

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