Oxygen supply is one of the major factors determining the metabolic state in microorganisms, and it affects the productivity of various compounds during bioproduction. In Escherichia coli (E. coli ), the expression levels of numerous metabolic genes are regulated by transcription factors in response to changes in environmental oxygen conditions. Even at a same dissolved oxygen concentration, the amount of available oxygen changes depending on the oxygen transfer coefficient. However, it is not known whether E. coli is able to sense differences in the oxygen consumption rate. Therefore, the present study, is focused on the role of the transcription factor ArcA in the oxygen response of E. coli and investigated the relationship between ArcA activity and the oxygen consumption rate. To evaluate the activity of ArcA, a sensor plasmid expressing fluorescent protein under the control of the icd promoter, which is regulated by ArcA, is designed. E. coli containing the sensor plasmid is grown in continuous cultures with different oxygen supplies under different dilution rates. Although there is no correlation between ArcA activity and dissolved oxygen concentration, a strong negative correlation between ArcA activity and the specific oxygen consumption rate (R ² > 0.93) is observed.

中文翻译：

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转录因子ArcA是一种用于大肠杆菌耗氧率的通量传感器。

氧气供应是决定微生物代谢状态的主要因素之一，它会影响生物生产过程中各种化合物的生产率。在大肠杆菌（E.coli）中，响应于环境氧条件的变化，许多代谢基因的表达水平受转录因子调节。即使在相同的溶解氧浓度下，有效氧的量也会根据氧的传递系数而变化。但是，尚不知道大肠杆菌是否能够感知耗氧率的差异。因此，本研究的重点是转录因子ArcA在大肠杆菌的氧气反应中的作用。并研究了ArcA活性与耗氧率之间的关系。为了评估ArcA的活性，设计了一种在icd启动子控制下表达荧光蛋白的传感器质粒，该质粒受ArcA调控。含有传感器质粒的大肠杆菌在不同稀释度的不同氧气供应下连续培养。尽管ArcA活性与溶解氧浓度之间没有相关性，但观察到ArcA活性与比氧消耗率之间存在很强的负相关性（R ² > 0.93）。