Cold adaptation of eicosapentaenoic acid-less mutant of Shewanella livingstonensis Ac10 involving uptake and remodeling of synthetic phospholipids containing various polyunsaturated fatty acids.
An Antarctic psychrotrophic bacterium, Shewanella livingstonensis Ac10, produces cis-5,8,11,14,17-eicosapentaenoic acid (EPA), a long-chain polyunsaturated fatty acid (LPUFA), as a component of membrane phospholipids at low temperatures. The EPA-less mutant generated by disruption of the EPA synthesis gene becomes cold-sensitive. We studied whether the cold sensitivity could be suppressed by supplementation of various LPUFAs. The EPA-less mutant was cultured at 6 degrees C in the presence of synthetic phosphatidylethanolamines (PEs) that contained oleic acid at the sn-1 position and various C20 fatty acids with different numbers of double bonds from zero to five or cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) at the sn-2 position. Mass spectrometric analyses revealed that all these fatty acids became components of various PE and phosphatidylglycerol species together with shorter partner fatty acids, indicating that large-scale remodeling followed the incorporation of synthetic PEs. As the number of double bonds in the sn-2 acyl chain decreased, the growth rate decreased and the cells became filamentous. The growth was restored to the wild-type level only when the medium was supplemented with phospholipids containing EPA or DHA. We found that about a half of DHA was converted into EPA. The results suggest that intact EPA is best required for cold adaptation of this bacterium.
Sato
Sho
S
Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan.
Kurihara
Tatsuo
T
Kawamoto
Jun
J
Hosokawa
Masashi
M
Sato
Satoshi B
SB
Esaki
Nobuyoshi
N
D000222:Adaptation, Physiological; D002853:Chromatography, Liquid; D003080:Cold Temperature; D015118:Eicosapentaenoic Acid / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D020592:Shewanella / Q000254:growth & development / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
D005231:Fatty Acids, Unsaturated; D010743:Phospholipids; D015118:Eicosapentaenoic Acid