School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8501, Japan.
Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan.
Biotechnol J. 2018 May;13(5):e1700612. doi: 10.1002/biot.201700612. Epub 2018 Feb 5.
Corynebacterium glutamicum is known for its ability to produce glutamic acid and has been utilized for the fermentative production of various amino acids. Glutamic acid production in C. glutamicum is induced by penicillin. In this study, the transcriptome and metabolome of C. glutamicum is analyzed to understand the mechanism of penicillin-induced glutamic acid production. Transcriptomic analysis with DNA microarray revealed that expression of some glycolysis- and TCA cycle-related genes, which include those encoding the enzymes involved in conversion of glucose to 2-oxoglutaric acid, is upregulated after penicillin addition. Meanwhile, expression of some TCA cycle-related genes, encoding the enzymes for conversion of 2-oxoglutaric acid to oxaloacetic acid, and the anaplerotic reactions decreased. In addition, expression of NCgl1221 and odhI, encoding proteins involved in glutamic acid excretion and inhibition of the 2-oxoglutarate dehydrogenase, respectively, is upregulated. Functional category enrichment analysis of genes upregulated and downregulated after penicillin addition revealed that genes for signal transduction systems are enriched among upregulated genes, whereas those for energy production and carbohydrate and amino acid metabolisms are enriched among the downregulated genes. As for the metabolomic analysis using capillary electrophoresis time-of-flight mass spectrometry, the intracellular content of most metabolites of the glycolysis and the TCA cycle decreased dramatically after penicillin addition. Overall, these results indicate that the cellular metabolism and glutamic acid excretion are mainly optimized at the transcription level during penicillin-induced glutamic acid production by C. glutamicum.
谷氨酸棒杆菌以其生产谷氨酸的能力而闻名，已被用于各种氨基酸的发酵生产。青霉素诱导谷氨酸棒杆菌生产谷氨酸。在这项研究中，分析了谷氨酸棒杆菌的转录组和代谢组，以了解青霉素诱导谷氨酸生产的机制。用 DNA 微阵列进行的转录组分析表明，一些糖酵解和 TCA 循环相关基因的表达上调，这些基因包括参与将葡萄糖转化为 2-酮戊二酸的酶的基因。同时，一些 TCA 循环相关基因的表达下调，这些基因编码将 2-酮戊二酸转化为草酰乙酸的酶和补料反应。此外，NCgl1221 和 odhI 的表达上调，分别编码与谷氨酸排泄和抑制 2-酮戊二酸脱氢酶有关的蛋白质。青霉素添加后上调和下调基因的功能类别富集分析表明，上调基因中富集了信号转导系统的基因，而下调基因中富集了能量产生和碳水化合物及氨基酸代谢的基因。至于使用毛细管电泳飞行时间质谱的代谢组学分析，青霉素添加后，糖酵解和 TCA 循环的大多数代谢物的细胞内含量急剧下降。总的来说，这些结果表明，在青霉素诱导谷氨酸棒杆菌生产谷氨酸的过程中，细胞代谢和谷氨酸排泄主要在转录水平上得到优化。
