Department of Chemistry, State University of New York-College of Environmental Science and Forestry, Syracuse, NY 13210, USA.
J Biosci Bioeng. 2010 Dec;110(6):653-9. doi: 10.1016/j.jbiosc.2010.08.001.
Pseudomonas putida has a variety of potential uses in bioremediation and biosynthesis of biodegradable plastics. P. putida is able to utilize a wide range of carbon sources. In this study, P. putida KT2440 was grown on glucose, glycerol, citrate, or fatty acid (lauric acid) as the sole carbon source. Differences in expression levels of genes involved in the Entner-Doudoroff pathway, glycerol metabolism, TCA cycle and β-oxidation were detected using quantitative real-time PCR. When glycerol was the sole carbon source, expression of genes related to glycerol metabolism was enhanced with the exception of the negative regulon gene glpR. There were no significant differences in expression levels of genes that putatively encode enzymes involved in the Entner-Doudoroff pathway for cells grown on glucose as compared to cells grown on other carbon sources. Exceptions to this trend were the ABC transporter genes. Genes encoding enzymes selected from the TCA cycle all showed higher expression levels in cells grown on citrate. Two genes for β-oxidation enzymes, fadB and the long-chain fatty acid transporter gene, showed higher expression level when cells were grown on lauric acid. Genes encoding enzymes involved in PHA synthesis, phaC1, phaC2, phaZ, and phaJ4, all showed higher expression levels when cells were grown on lauric acid. This study has identified genes involved in the metabolism of different carbon sources and PHA synthesis. This information will be invaluable to understand how genes are regulated and construct transgenic strains to utilize carbon sources more efficiently and better produce PHAs.
恶臭假单胞菌在生物修复和可生物降解塑料的生物合成方面具有多种潜在用途。恶臭假单胞菌能够利用广泛的碳源。在这项研究中，恶臭假单胞菌 KT2440 以葡萄糖、甘油、柠檬酸或脂肪酸（月桂酸）作为唯一碳源进行培养。使用定量实时 PCR 检测参与 Entner-Doudoroff 途径、甘油代谢、TCA 循环和β-氧化的基因的表达水平差异。当甘油作为唯一碳源时，除了负调控基因 glpR 外，与甘油代谢相关的基因表达增强。与其他碳源相比，在以葡萄糖为唯一碳源的细胞中，参与 Entner-Doudoroff 途径的酶的编码基因的表达水平没有显著差异。这一趋势的例外是 ABC 转运基因。从 TCA 循环中选择的编码酶的基因在细胞生长在柠檬酸上时表现出更高的表达水平。两种β-氧化酶基因 fadB 和长链脂肪酸转运基因，当细胞生长在月桂酸上时，表现出更高的表达水平。参与 PHA 合成的酶基因 phaC1、phaC2、phaZ 和 phaJ4，当细胞生长在月桂酸上时，表达水平均较高。本研究鉴定了参与不同碳源代谢和 PHA 合成的基因。这些信息对于理解基因如何调控以及构建能够更有效地利用碳源和更好地生产 PHAs 的转基因菌株将是非常宝贵的。
