Although cyanobacteria do not possess wax ester synthase/acyl-CoA:diacylglycerol acyltransferase (WS/DGAT), the bacterial enzyme for triacylglycerol (TAG) production, there have been several studies reporting the accumulation of TAG-like compounds in cyanobacteria. In this study, we aimed to evaluate TAG productivity of the ΔrecJ::atfA strain of Synechocystis sp. PCC 6803 generated by inserting atfA encoding WS/DGAT from Acinetobacter baylyi ADP1 into recJ (sll1354), together with the wild type (WT) and the gene-disrupted strain of slr2103 having homology with eukaryotic DGAT2 gene family (Δ2103). Thin-layer chromatography (TLC) of neutral lipids or isolation of the neutral lipid-enriched fraction followed by gas chromatography or liquid chromatography–tandem mass spectrometry was employed for analyses. The ΔrecJ::atfA strain accumulated 0.508 nmol ml⁻¹$OD730−1$ of TAG after a week of incubation at 100 μmol photons m⁻² s⁻¹. The saturated fatty acids C16:0 and C18:0 accounted for about 50% and 20% of the TAG fatty acids, respectively, suggesting that de novo-synthesized fatty acids were preferentially incorporated into TAG molecules. When the neutral lipid profile of the lipid extracts was examined by TLC, a spot located in a slightly lower position compared with the TAG standard was detected in WT but not in the Δ2103 strain. TAG accumulation levels of both strains was only 0.01–0.03 nmol ml⁻¹$OD730−1$⁠, but the fatty acid composition was substantially different from that of the background. These results suggest that trace amounts of TAG can be produced in Synechocystis cells by enzymes other than Slr2103, and major constituents of the TAG-like spot are unknown lipid species produced by Slr2103.

中文翻译：

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定量和定性分析在野生型蓝藻蓝藻中的三酰基甘油产量。PCC 6803和来自不动杆菌Baylyi ADP1的AtfA菌株。

尽管蓝细菌不具有蜡酯合酶/酰基-CoA：二酰基甘油酰基转移酶（WS / DGAT）（三酰甘油（TAG）生产的细菌酶），但已有几项研究报道了TAG样化合物在蓝细菌中的积累。在这项研究中，我们旨在评估集胞藻属sp。的ΔrecJ :: atfA菌株的TAG生产力。6803通过将所产生ATFA来自编码WS / DGAT不动杆菌baylyi ADP1成recJ（sll1354），与野生型（WT）和的基因被破坏的菌株一起slr2103与真核DGAT2基因家族具有同源性（Δ 2103）。使用中性脂质的薄层色谱（TLC）或分离中性脂质富集的馏分，然后进行气相色谱或液相色谱-串联质谱分析。该Δ recJ :: ATFA应变积累0.508纳摩尔毫升^-1$外径730-1个$在100μmol光子m ^-2 s ^-1下孵育一周后的TAG值。饱和脂肪酸C16：0和C18：0分别约占TAG脂肪酸的50％和20％，这表明从头合成的脂肪酸优先掺入TAG分子中。当通过TLC检查脂质提取物的中性脂质谱时，在WT中检测到与TAG标准品相比略低位置的斑点，但在Δ2103菌株中未检测到。两种菌株的TAG积累水平仅为0.01–0.03 nmol ml ^-1$外径730-1个$⁠，但脂肪酸组成与背景基本不同。这些结果表明，除Srr2103以外的其他酶也可在突囊藻细胞中产生痕量的TAG ，并且TAG样斑点的主要成分是Slr2103产生的未知脂质。