■短小左杆菌CRL2013,一种具有免疫调节特性的植物来源的乳酸菌(LAB),已成为γ-氨基丁酸(GABA)的有效生产者。值得注意的是,并非所有LAB都具有产生GABA的能力,强调特定遗传和环境条件对GABA合成的重要性。本研究旨在阐明L.brevisCRL2013有趣的GABA生产机制,并通过全面的基因组分析支持其安全应用的潜力。
■对短乳杆菌CRL2013进行了全面的基因组分析,以确定是否存在抗生素抗性基因,毒力标记,以及与谷氨酸脱羧酶系统相关的基因,这对GABA生物合成至关重要。然后,优化的化学成分确定的培养基(CDM)补充了味精(MSG)和酵母提取物(YE),以分析它们对GABA生产的影响。进行蛋白质组学和转录分析以评估与GABA产生相关的蛋白质和基因表达的变化。
■短乳杆菌CRL2013基因组中缺乏抗生素抗性基因和毒力标记,这支持了其潜在益生菌应用的安全性。编码谷氨酸脱羧酶系统的基因,包括两个gad基因(gadA和gadB)和谷氨酸反转运基因(gadC),已确定。gadB基因位于gadC附近,而gadA分别位于染色体上。在gadC的上游发现了转录调节因子gadR,转录分析表明gadR与gadC的共同转录。虽然单独补充味精不能激活GABA合成,在优化的含谷氨酸的CDM中,YE的添加显着提高了GABA的产量。蛋白质组学分析显示,MSG补充和未补充的CDM培养物之间的差异最小,而YE补充导致显著的蛋白质组变化,包括GadB的上调。转录分析证实补充YE后gadB和gadR的表达增加,支持其在激活GABA生产中的作用。
■这些发现为营养成分对GABA生产的影响提供了有价值的见解。此外,他们揭示了L.brevisCRL2013作为安全的潜力,具有有价值的生物技术特征的非致病性菌株,可以进一步利用其在食品工业中的益生菌潜力。
UNASSIGNED: Levilactobacillus brevis CRL 2013, a plant-derived lactic acid bacterium (LAB) with immunomodulatory properties, has emerged as an efficient producer of γ-aminobutyric acid (GABA). Notably, not all LAB possess the ability to produce GABA, highlighting the importance of specific genetic and environmental conditions for GABA synthesis. This study aimed to elucidate the intriguing GABA-producing machinery of L. brevis CRL 2013 and support its potential for safe application through comprehensive genome analysis.
UNASSIGNED: A comprehensive genome analysis of L. brevis CRL 2013 was performed to identify the presence of antibiotic resistance genes, virulence markers, and genes associated with the glutamate decarboxylase system, which is essential for GABA biosynthesis. Then, an optimized chemically defined culture medium (CDM) was supplemented with monosodium glutamate (MSG) and yeast extract (YE) to analyze their influence on GABA production. Proteomic and transcriptional analyses were conducted to assess changes in protein and gene expression related to GABA production.
UNASSIGNED: The absence of antibiotic resistance genes and virulence markers in the genome of L. brevis CRL 2013 supports its safety for potential probiotic applications. Genes encoding the glutamate decarboxylase system, including two gad genes (gadA and gadB) and the glutamate antiporter gene (gadC), were identified. The gadB gene is located adjacent to gadC, while gadA resides separately on the chromosome. The transcriptional regulator gadR was found upstream of gadC, with transcriptional analyses demonstrating cotranscription of gadR with gadC. Although MSG supplementation alone did not activate GABA synthesis, the addition of YE significantly enhanced GABA production in the optimized CDM containing glutamate. Proteomic analysis revealed minimal differences between MSG-supplemented and non-supplemented CDM cultures, whereas YE supplementation resulted in significant proteomic changes, including upregulation of GadB. Transcriptional analysis confirmed increased expression of gadB and gadR upon YE supplementation, supporting its role in activating GABA production.
UNASSIGNED: These findings provide valuable insights into the influence of nutrient composition on GABA production. Furthermore, they unveil the potential of L. brevis CRL 2013 as a safe, nonpathogenic strain with valuable biotechnological traits which can be further leveraged for its probiotic potential in the food industry.