Bacteria that belong to Shewanella, Moritella, Colwellia, Photobacterium, and other genera synthesize de novo. The bacterial enzymes for the synthesis of these fatty acids share sequence similarity with polyketide synthases. Their synthesis proceeds in an oxygen molecule-independent manner, implying that the double bonds are introduced by dehydratase, not by desaturase. Comparison of phenotypes of EPA-producing Shewanella livingstonensis Ac10 and Shewanella violacea DSS12, EPA is required for

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... eir normal cell division at low temperatures and high pressures, respectively. In these bacteria, EPA depletion does not cause an than increasing membrane fluidity. A fluorescent analog of EPA-containing phospholipids was shown to accumulate at the cell division site of S. livingstonensis Ac10, suggesting that EPA-containing phospholipids Shewanella marinintestina IK-1, EPA depletion increases sensitivity to hydrophilic growth inhibitors such as hydrogen peroxide and resistance to hydrophobic compounds, suggesting a membrane-shielding function of EPA. Recent studies indicate that EPA is also involved in the biogenesis of membrane proteins and extracellular membrane vesicles.