Agricultural Bioresources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, China.
J Appl Microbiol. 2022 Mar;132(3):2167-2176. doi: 10.1111/jam.15347. Epub 2021 Nov 9.
This study aimed to investigate the effect of metal ions on lipopeptide production by Bacillus subtilis strain FJAT-4 and the mechanism of negative regulation by Ca .
The quantitative measurement of lipopeptides in response to K , Na , Mg and Ca addition was carried out by LC-MS. The contents of fengycin and surfactin varied within the range of 116.24-129.80 mg/L and 34.03-63.11 mg/L in the culture media containing K , Na and Mg , while the levels were 0.86 and 0.63 mg/L in the media containing Ca . Ca at a high concentration (45 mM) did not adversely affect the growth of strain FJAT-4, but caused significant downregulation of lipopeptide synthesis-related gene expression, corresponding to a decrease in lipopeptide production. This inhibition by Ca was further investigated by proteomic analysis. In total, 112 proteins were upregulated and 524 proteins were downregulated in the presence of additional Ca (45 mM). Among these differentially expressed proteins (DEPs), 28 were related to phosphotransferase activity, and 42 were related to kinase activity. The proteomics results suggested that altered levels of three two-component signal-transduction systems (ResD/ResE, PhoP/PhoR and DegU/DegS) might be involved in the control of expression of the fen and srfA operons of FJAT-4 under high calcium stress.
The Ca at the high concentration (45 mM) triggers a decrease in lipopeptide production, which might be attributed to the regulation of three two-component signal-transduction systems ResD/ResE, PhoP/PhoR and DegU/DegS.
The regulatory effect of calcium on the expression of genes encoding lipopeptide synthetases can be applied to optimize the production of lipopeptides.
本研究旨在探讨金属离子对枯草芽孢杆菌 FJAT-4 菌株脂肽生产的影响，以及 Ca2+的负调控机制。
通过 LC-MS 对添加 K+、Na+、Mg2+和 Ca2+后脂肽的定量测量表明，在含有 K+、Na+和 Mg2+的培养基中，丰原素和表面活性剂的含量分别在 116.24-129.80mg/L 和 34.03-63.11mg/L 范围内，而在含有 Ca2+的培养基中含量分别为 0.86 和 0.63mg/L。高浓度 Ca2+（45mM）不会对 FJAT-4 菌株的生长产生不利影响，但会导致脂肽合成相关基因表达的显著下调，相应地降低脂肽的产生。通过蛋白质组学分析进一步研究了 Ca2+的这种抑制作用。在添加额外 Ca2+（45mM）的情况下，共上调了 112 种蛋白，下调了 524 种蛋白。在这些差异表达蛋白（DEPs）中，有 28 种与磷酸转移酶活性有关，有 42 种与激酶活性有关。蛋白质组学结果表明，三个双组分信号转导系统（ResD/ResE、PhoP/PhoR 和 DegU/DegS）的水平变化可能参与了高钙胁迫下 FJAT-4 的 fen 和 srfA 操纵子的表达调控。
高浓度（45mM）Ca2+触发脂肽产量下降，这可能归因于三个双组分信号转导系统 ResD/ResE、PhoP/PhoR 和 DegU/DegS 的调节。
钙对脂肽合成酶编码基因表达的调节作用可应用于优化脂肽的生产。
