酸胁迫下乳酸乳球菌IMAU51121的代谢组学研究

Metabolomics Analysis of Lactococcus lactis IMAU51121 Under Acid Stress

摘要:

目的 探究酸胁迫下乳酸乳球菌（Lactococcus lactis，L. lactis）IMAU51121的代谢物变化。方法 将L. lactis IMAU51121在pH为4.0的GM17肉汤培养基中酸胁迫0.5 h，用液相色谱-质谱联用（LC-MS）技术检测酸胁迫前后的代谢物变化，采用多元统计方法对代谢组学数据进行比较分析。结果 共鉴定到1 178种代谢物，根据变量投影重要性（VIP）≥1、P<0.05和差异倍数（FC）>1.2的条件共筛选到20种主要差异代谢物。在酸胁迫后，L-组氨酸、天冬氨酸、异亮氨酸等11种代谢物相对含量增加，瓜氨酸、β-酪氨酸、尿苷二磷酸（UDP）-葡萄糖等9种代谢物相对含量下降。KEGG通路富集及拓扑分析表明，酸胁迫影响了精氨酸生物合成、半乳糖代谢等5条关键差异代谢通路。结论 酸胁迫影响L. lactis IMAU51121的生长和代谢，L. lactis IMAU51121通过调整氨基酸、糖、脂类、核苷酸等物质水平及代谢通路来抵御酸胁迫。

Abstract:

Objective The aim of the study is to investigate the metabolite changes of Lactococcus lactis (L. lactis) IMAU51121 under acid stress.Method L. lactis IMAU51121 was exposed to acid stress in the GM17 liquid medium at pH 4.0 for 0.5 h. The metabolites changes before and after acid stress were detected by liquid chromatography-mass spectrometry (LC-MS). The multivariate statistical analysis was performed for metabolomics data.Result In total, 1 178 metabolites were identified, from which 20 major differential metabolites were screened based on variable importance in projection (VIP)≥1, P<0.05, and fold change (FC)>1.2. After acid stress, 11 metabolites showed increased relative content, including L-histidine, aspartic acid, and isoleucine, while 9 metabolites demonstrated decreased relative content, including citrulline, β-tyrosine, and uridine diphosphate (UDP)-glucose. KEGG pathway enrichment and topological analysis revealed that acid stress affected five key differential metabolic pathways, including arginine biosynthesis and galactose metabolism.Conclusion Acid stress affects the growth and metabolism of L. lactis IMAU51121, which responds to acid stress by adjusting the levels of amino acids, sugars, lipids, and nucleotides and the metabolic pathways.