College of Biosystems Engineering and Food Science, Fuli Institute of Food Science, Zhejiang Key Laboratory for Agro-Food Processing, Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang University, Hangzhou 310058, Zhejiang, China.
Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan 430068, Hubei, China.
Bioresour Technol. 2018 Feb;249:234-240. doi: 10.1016/j.biortech.2017.10.012. Epub 2017 Oct 6.
Validamycin A (Val-A) is produced by Streptomyces as a secondary metabolite with wide agricultural applications of controlling rice sheath blight, false smut and damping-off diseases. The effect of alkaline pH shock on enhancing Val-A production and its mechanism were investigated. A higher yield of Val-A was achieved by NaOH shock once or several times together with faster protein synthesis and sugar consumption and alkaline pH shock can increase Val-A production by 27.43%. Transcription of genes related to amino acid metabolism, carbon metabolism and electron respiratory chain was significantly up-regulated, accompanied by the substantial increase of respiratory activity and glutamate concentration. Val-A production was promoted by a series of complex mechanisms and made a response to pH stress signal, which led to the enhancement of glutamate metabolism and respiration activity. The obtained information will facilitate future studies for antibiotic yield improvement and the deep revealment of molecular mechanism.
井冈霉素 A（Val-A）是一种由链霉菌产生的次级代谢产物，具有广泛的农业应用，可防治水稻纹枯病、假黑穗病和猝倒病。本研究考察了碱性 pH 冲击对井冈霉素 A 生产的影响及其机制。NaOH 冲击一次或多次可以提高井冈霉素 A 的产量，同时加快蛋白质合成和糖消耗，碱性 pH 冲击可使井冈霉素 A 的产量提高 27.43%。与氨基酸代谢、碳代谢和电子呼吸链相关的基因转录明显上调，伴随着呼吸活性和谷氨酸浓度的大幅增加。井冈霉素 A 的生产是通过一系列复杂的机制来促进的，并对 pH 应激信号做出反应，从而导致谷氨酸代谢和呼吸活性的增强。这些结果将有助于未来抗生素产量提高和分子机制的深入研究。
