Time-of-flight secondary ion mass spectrometry (ToF-SIMS) using a primary ion beam of (CO₂)_6k⁺ was used to analyse chemical changes in the bacterial envelope of a fabF knock-out Escherichia coli strain. fabF is the gene coding for FabF, the enzyme involved in the elongation of FA(16:1) to FA(18:1) and has been associated with plasmid transfer that can lead to acquired multiantibiotic resistance. Comparison of the membrane composition between fabF mutant E. coli and wild type E. coli during the logarithmic and stationary growth phases at two culture temperatures (37°C and 30°C) revealed substantial depletion of FA(18:1) in the fabF mutant during logarithmic growth that resulted in a correlated reduction in FA(cp19:0) during stationary phase. While no clear temperature dependence on the effect of the fabF mutation was found, a reduction in cyclopropanation was observed at lower culture temperature in the wild type strain. Additionally, depth profile analysis revealed a ‘thickening’ of the lipid A layer on the surface of the bacteria during stationary phase and also the appearance of cyclic enterobacterial common antigen (ECA_CYC) below the surface of the bacteria upon the shift from logarithmic to stationary growth phase.

中文翻译：

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使用飞行时间二次离子质谱法询问大肠杆菌 FabF 突变体细菌包膜上和通过的化学变化

使用 (CO ₂ ) _6k ⁺初级离子束的飞行时间二级离子质谱法 (ToF-SIMS)用于分析fabF敲除大肠杆菌菌株的细菌包膜中的化学变化。fabF是编码FabF的基因，该酶参与 FA(16:1) 到 FA(18:1) 的延伸，并与可导致获得性多抗生素耐药性的质粒转移有关。fabF突变型大肠杆菌和野生型大肠杆菌膜成分的比较在两个培养温度（37°C 和 30°C）下的对数和稳定生长期期间，在对数生长期间fabF突变体中FA（18:1）的大量消耗导致 FA（cp19:0）的相关减少在静止期。虽然没有发现明显的温度依赖于fabF突变的影响，但在野生型菌株中在较低的培养温度下观察到环丙烷化的减少。此外，深度剖面分析显示，在稳定期细菌表面的脂质 A 层“增厚”，并且在从对数转移到稳定期时，细菌表面下方出现了环状肠杆菌共同抗原 (ECA _CYC )。成长阶段。