Mechanisms of Acetoin Toxicity and Adaptive Responses in an Acetoin-Producing Species, Lactococcus lactis.
Mechanisms of Acetoin Toxicity and Adaptive Responses in an Acetoin-Producing Species, Lactococcus lactis.
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DOI：
10.1128/aem.01079-21
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发表时间：
2021-11-24
影响因子：
4.4
通讯作者：
Gaudu P
中科院分区：
文献类型：
--
作者：
Cesselin B;Henry C;Gruss A;Gloux K;Gaudu P
乙偶姻，3-羟基，2-丁酮，广泛用作食品中的风味添加剂。这种挥发性化合物由乳细菌乳酸乳球菌在通过血红素添加激活有氧呼吸时产生，并且包含约70%的碳水化合物降解产物。本文研究了乙偶姻毒性作用的靶点，并确定了乙偶姻如何影响L。乳酸生理学和生存。乙偶姻对DNA和蛋白质的损伤与其酮基的活性有关。乙偶姻应激反映在蛋白质组图谱中，其揭示了脂质代谢蛋白的变化。乙偶姻引起脂肪酸组成的显着变化，与大量积累的cycC 19：0环丙烷脂肪酸在其不饱和C18：1脂肪酸前体的费用。缺失cfa基因，编码cycC 19：0合酶，敏感细胞乙偶姻应激。乙偶姻抗性转座子诱变揭示了高亲和力磷酸盐转运操纵子pstABCDEF中的热点，已知其增加对多种胁迫的抗性。本研究揭示了乙偶姻胁迫对L.乳酸菌，并且可以促进在工艺过程中控制乳酸菌的生产。重要信息乙偶姻，3-羟基，2-丁酮，作为一种产生香味的挥发性化合物，在化学工业，农业和乳制品工业中有多种用途。在细菌中，当乳酸乳球菌在有氧呼吸下生长时，它可以大量产生。然而，乙偶姻的产生对于生长和/或存活可能是有毒的和有害的。我们的研究结果表明，它通过其酮基损伤DNA和蛋白质。我们还表明，乙偶姻修改膜的脂肪酸组成与生产的环丙烷C19：0脂肪酸的不饱和C18：1的费用。我们分离的突变体更耐乙偶姻比野生型菌株。所有这些都映射到一个单一的基因座pstABCDEF操纵子，这表明一个简单的方法来限制乙偶姻毒性在乳制品细菌，并提高其生产。
Acetoin, 3-hydroxyl,2-butanone, is extensively used as a flavor additive in food products. This volatile compound is produced by the dairy bacterium Lactococcus lactis when aerobic respiration is activated by haem addition, and comprises ∼70% of carbohydrate degradation products. Here we investigate the targets of acetoin toxicity, and determine how acetoin impacts L. lactis physiology and survival. Acetoin caused damage to DNA and proteins, which related to reactivity of its keto group. Acetoin stress was reflected in proteome profiles, which revealed changes in lipid metabolic proteins. Acetoin provoked marked changes in fatty acid composition, with massive accumulation of cycC19:0 cyclopropane fatty acid at the expense of its unsaturated C18:1 fatty acid precursor. Deletion of the cfa gene, encoding the cycC19:0 synthase, sensitized cells to acetoin stress. Acetoin-resistant transposon mutagenesis revealed a hot spot in the high affinity phosphate transporter operon pstABCDEF, which is known to increase resistance to multiple stresses. This work reveals the causes and consequences of acetoin stress on L. lactis, and may facilitate control of lactic acid bacteria production in technological processes. IMPORTANCE Acetoin, 3-hydroxyl,2-butanone, has diverse uses in chemical industry, agriculture, and dairy industries as a volatile compound that generates aromas. In bacteria, it can be produced in high amount by Lactococcus lactis when it grows under aerobic respiration. However, acetoin production can be toxic and detrimental for growth and/or survival. Our results showed that it damages DNA and proteins via its keto group. We also showed that acetoin modifies membrane fatty acid composition with the production of cyclopropane C19:0 fatty acid at the expense of an unsaturated C18:1. We isolated mutants more resistant to acetoin than the wild-type strain. All of them mapped to a single locus pstABCDEF operon, suggesting a simple means to limit acetoin toxicity in dairy bacteria and to improve its production.