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HE Rong Qiao 《中国科学:生命科学英文版》2014,(12)
<正>On the day of Oct.6,2014,John O’Keefe and a Norwegian couple May-Britt Moser and Edvard Moser won the Nobel Prize in Physiology or Medicine for discovering the"inner GPS"that functions in the brain when the animals navigate through the world.The prize was awarded for their work in identifying the cells that make up the positioning system in the mammalian brain. 相似文献
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Artur Schuller Monika Cserjan-Puschmann Christoph Köppl Reingard Grabherr Martin Wagenknecht Matteo Schiavinato Juliane C. Dohm Heinz Himmelbauer Gerald Striedner 《Biotechnology journal》2021,16(3):2000376
The production of recombinant proteins usually reduces cell fitness and the growth rate of producing cells. The growth disadvantage favors faster-growing non-producer mutants. Therefore, continuous bioprocessing is hardly feasible in Escherichia coli due to the high escape rate. The stability of E. coli expression systems under long-term production conditions and how metabolic load triggered by recombinant gene expression influences the characteristics of mutations are investigated. Iterated fed-batch-like microbioreactor cultivations are conducted under production conditions. The easy-to-produce green fluorescent protein (GFP) and a challenging antigen-binding fragment (Fab) are used as model proteins, and BL21(DE3) and BL21Q strains as expression hosts. In comparative whole-genome sequencing analyses, mutations that allowed cells to grow unhindered despite recombinant protein production are identified. A T7 RNA polymerase expression system is only conditionally suitable for long-term cultivation under production conditions. Mutations leading to non-producers occur in either the T7 RNA polymerase gene or the T7 promoter. The host RNA polymerase-based BL21Q expression system remains stable in the production of GFP in long-term cultivations. For the production of Fab, mutations in lacI of the BL21Q derivatives have positive effects on long-term stability. The results indicate that adaptive evolution carried out with genome-integrated E. coli expression systems in microtiter cultivations under industrial-relevant production conditions is an efficient strain development tool for production hosts. 相似文献
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