Table 1.
Strains and plasmids used in this study.
Fig 1.
Production of DHA in four E. coli strains by heterologous expression of Colwellia pfaABCD and pfaE.
The cells were cultured at 15°C with shaking at 180 rpm. The quantification of DHA from each sample was repeated in triplicate (n = 3).
Fig 2.
Complementation of the function of Colwellia pfaABCD by four different individual pfaE genes: pfaE(DHA), pfaE from C. psychrerythraea; pfaE(DHA-M), pfaE from M. marina MP-1; pfaE(EPA), pfaE from S. baltica OS678; and pfaE(ARA), pfaE from Aureispira marina.
The cells were cultured at 15°C with shaking at 180 rpm. The quantification of DHA from each sample was repeated in triplicate (n = 3).
Fig 3.
Sequence alignments of the four PfaEs used in this study.
Colwellia, C. psychrerythraea 34H; Moritella, M. marina MP-1; Shewanella, S. baltica OS678; and Aureispira, A. marina. Identical amino acid residues are in black, and similar amino acids are in gray. Five putative conserved motifs are marked as P0, P1a, P1b, P2 and P3.
Fig 4.
Effect of temperature on the fatty acid profiles of recombinant cells harboring pColdI-pfaABCD and different pfaE genes.
(A) DH5α harboring pColdI-pfaABCD and pfaE(DHA); (B) DH5α harboring pColdI-pfaABCD and pfaE(DHA-M); (C) DH5α harboring pColdI-pfaABCD and pfaE(EPA); (D) DH5α harboring pColdI-pfaABCD and pfaE(ARA). The quantification of each fatty acid from samples was repeated in triplicate (n = 3).
Table 2.
Effect of temperature on DHA production by recombinant DH5α harboring pColdI-pfaABCD and different pfaE genes.
Table 3.
Effect of cerulenin on DHA production by recombinant DH5α harboring pColdI-pfaABCD and different pfaE.
Fig 5.
Effect of cerulenin on the fatty acid profile of recombinant cells harboring pColdI-pfaABCD and different pfaE genes.
(A) DH5α harboring empty vector pColdI; (B) DH5α harboring pColdI-pfaABCD; (C) DH5α harboring pColdI-pfaABCD and pfaE(DHA); (D) DH5α harboring pColdI-pfaABCD and pfaE(DHA-M); (E) DH5α harboring pColdI-pfaABCD and pfaE(EPA); (F) DH5α harboring pColdI-pfaABCD and pfaE(ARA). The cells were cultured at 15°C with shaking at 180 rpm. The final concentrations of added cerulenin were 0, 0.5, 1.0 or 2.0 mg/L, as shown in the legend. The quantification of each fatty acid from samples was repeated in triplicate (n = 3).