Abreu Sonia, Lejeune Clara, David Michelle, Chaminade Pierre, Virolle Marie-Joelle
Lip (Sys)2 (Lipides Systèmes Analytiques et Biologiques), UFR Pharmacie-Bâtiment Henri Moissan, CNRS, CEA, Université Paris-Saclay, 17 Avenue des Sciences, 91400 Orsay, France.
Institute for Integrative Biology of the Cell (I2BC), Department of Microbiology, Group "Energetic Metabolism of Streptomyces", CNRS, CEA, Université Paris-Saclay, 1 Avenue de la Terrasse, 91198 Gif-Sur-Yvette, France.
Microorganisms. 2024 Jul 30;12(8):1560. doi: 10.3390/microorganisms12081560.
Since nitrogen limitation is known to be an important trigger of triacylglycerol (TAG) accumulation in most microorganisms, we first assessed the global lipid content of 21 strains derived from M145 deleted for genes involved in nitrogen metabolism. Seven of these strains deleted for genes encoding proteins involved in polyamine (GlnA2/SCO2241, GlnA3/SCO6962, GlnA4/SCO1613), or protein (Pup/SCO1646) degradation, in the regulation of nitrogen metabolism (GlnE/SCO2234 and GlnK/SCO5584), or the global regulator DasR/SCO5231 that controls negatively the degradation of N-acetylglucosamine, a constituent of peptidoglycan, had a higher TAG content than the original strain, whereas five of these strains (except the and mutants) had a lower cardiolipin (CL) content. The production of the blue polyketide actinorhodin (ACT) was totally abolished in the mutant in both Pi conditions, whereas the deletion of , , , and was correlated with a significant increase in total ACT production, but mainly in Pi limitation. Unexpectedly, ACT production was strongly reduced in the mutant in Pi proficiency. Altogether, our data suggest that high TAG and ACT biosynthesis and low CL biosynthesis might all contribute to the lowering of oxidative stress resulting from nitrogen limitation or from other causes.
由于已知氮限制是大多数微生物中三酰甘油（TAG）积累的重要触发因素，我们首先评估了来自M145的21个缺失参与氮代谢基因的菌株的总体脂质含量。其中七个菌株缺失了编码参与多胺（GlnA2/SCO2241、GlnA3/SCO6962、GlnA4/SCO1613）或蛋白质（Pup/SCO1646）降解、氮代谢调节（GlnE/SCO2234和GlnK/SCO5584）或负调控肽聚糖成分N-乙酰葡糖胺降解的全局调节因子DasR/SCO5231的基因，其TAG含量高于原始菌株，而其中五个菌株（除了 和 突变体）的心磷脂（CL）含量较低。在两种磷条件下，蓝色聚酮放线紫红素（ACT）的产生在 突变体中完全被消除，而 、 、 和 的缺失与总ACT产量的显著增加相关，但主要是在磷限制条件下。出乎意料的是，在磷充足的情况下， 突变体中的ACT产量大幅降低。总之，我们的数据表明，高TAG和ACT生物合成以及低CL生物合成可能都有助于降低由氮限制或其他原因导致的氧化应激。
