Fatty acid and hydrocarbon composition in tropical marine Shewanella amazonensis strain SB2B^T

Abstract

Shewanella amazonensis strain SB2B(T) is an isolate from shallow-water marine sediments derived from the Amazon River delta. This bacterium contained a long-chain polyunsaturated hydrocarbon, all-cis -3,6,9,12,16,19,22,25,28 hentriacontanonaene (C31:9), constituting 1-2% of the total fatty acid methyl ester and hydrocarbon fraction, which was produced dependently of decreased growth temperature. Analysis of its cellular fatty acid composition demonstrated that isopentadecanoic acid was the major fatty acid component and that all the main monounsaturated fatty acids had straight chains with a cis configuration. However, monoenoic cyclopropyl fatty acids, which were previously reported to be present in this bacterium, were not detected by mass spectrometric analysis. The growth temperature affected the content of Δ9-cis -hexadecenoic [16:1(Δ9c)], palmitic, and heptadecanoic acids. These results suggest that C31:9, as well as 16:1(Δ9c) might be involved in adaptation to low temperature in S. amazonensis strain SB2B(T) . Our result suggests that polyunsaturated fatty acid synthase protein complex may be involved in synthesis of C31:9 but not in production of eicosapentaenoic acid.

Stereoselective synthesis of (all-Z)-hentriaconta-3,6,9,12,15,19,22,25,28-nonaene

“…In summary, the first total synthesis of the natural occurring VLCH compound (all-Z)-hentriaconta-3, 6,9,12,15,19,22,25,28-nonaene (1), has been achieved in eight steps and in 15% overall yield from the ethyl ester 6. Our synthesis confirmed the structure of 1.…”

“…9 Hence, a stereoselective total synthesis of the natural occurring VLCH 1 is required both for the exact structure elucidation and for providing enough material for conducting biological studies. 9 Hence, a stereoselective total synthesis of the natural occurring VLCH 1 is required both for the exact structure elucidation and for providing enough material for conducting biological studies.…”

“…Most likely, the C31:9 natural product 1 is involved in cold adaptation mechanisms beneficial for the bacteria. 9 Hence, a stereoselective total synthesis of the natural occurring VLCH 1 is required both for the exact structure elucidation and for providing enough material for conducting biological studies. These reasons, together with our interest in the synthesis of PUFA-derived natural products, 10 motivated us to achieve the first total synthesis of 1.…”

“…Starting from the ethyl ester of eicosapentaenoic acid, the total synthesis of the natural product (all-Z)-hentriaconta-3, 6,9,12,15,19,22,25,28-nonaene has been achieved in eight steps and 15% overall yield. Starting from the ethyl ester of eicosapentaenoic acid, the total synthesis of the natural product (all-Z)-hentriaconta-3, 6,9,12,15,19,22,25,28-nonaene has been achieved in eight steps and 15% overall yield.…”

Occurrence of trans monounsaturated and polyunsaturated fatty acids in Colwellia psychrerythraea strain 34H

“…Most of these LC‐PUFA‐producing bacterial species were isolated from cold marine environments: deep sea water and sediments, as well as the polar regions. However, reports of LC‐PUFA‐producing bacteria isolated from marine temperate and even subtropical regions are also accumulating . Major LC‐PUFAs of these bacteria are eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA) and have been regarded as modulators of membrane fluidity due to their lower melting temperatures and thus the lower gel‐to‐liquid crystalline phase‐transition temperatures of the LC‐PUFA‐containing membrane phospholipids.…”