Transcriptome analysis of parallel-evolved Escherichia coli strains under ethanol stress

BMC Genomics

Research Article

Naoaki Ono¹  Kuniyasu Tamaoka¹  Takaaki Horinouchi¹  Takashi Hirasawa¹  Chikara Furusawa¹  Shingo Suzuki¹  Hiroshi Shimizu¹  Tetsuya Yomo² 

[1] Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, Japan;Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka, Japan;Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), 1-5 Yamadaoka, Suita, Osaka, Japan;Graduate School of Frontier Biosciences, Osaka University, 1-5 Yamadaoka, Suita, Osaka, Japan;

关键词: Specific Growth Rate;    Adaptive Evolution;    Ethanol Tolerance;    Tolerant Strain;    Amino Acid Supplementation;   

DOI  :  10.1186/1471-2164-11-579

 received in 2010-07-26, accepted in 2010-10-19,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundUnderstanding ethanol tolerance in microorganisms is important for the improvement of bioethanol production. Hence, we performed parallel-evolution experiments using Escherichia coli cells under ethanol stress to determine the phenotypic changes necessary for ethanol tolerance.ResultsAfter cultivation of 1,000 generations under 5% ethanol stress, we obtained 6 ethanol-tolerant strains that showed an approximately 2-fold increase in their specific growth rate in comparison with their ancestor. Expression analysis using microarrays revealed that common expression changes occurred during the adaptive evolution to the ethanol stress environment. Biosynthetic pathways of amino acids, including tryptophan, histidine, and branched-chain amino acids, were commonly up-regulated in the tolerant strains, suggesting that activating these pathways is involved in the development of ethanol tolerance. In support of this hypothesis, supplementation of isoleucine, tryptophan, and histidine to the culture medium increased the specific growth rate under ethanol stress. Furthermore, genes related to iron ion metabolism were commonly up-regulated in the tolerant strains, which suggests the change in intracellular redox state during adaptive evolution.ConclusionsThe common phenotypic changes in the ethanol-tolerant strains we identified could provide a fundamental basis for designing ethanol-tolerant strains for industrial purposes.

【 授权许可】

Unknown   
© Horinouchi et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.