Improving E. coli growth performance by manipulating small RNA expression.
Improving E. coli growth performance by manipulating small RNA expression.
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DOI：
10.1186/s12934-017-0810-x
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发表时间：
2017-11-14
影响因子：
6.4
通讯作者：
Shiloach J
中科院分区：
文献类型：
--
作者：
Negrete A;Shiloach J
自20世纪70年代初以来，大肠杆菌的高效生长，特别是重组蛋白的生产，一直是生物技术行业面临的挑战。通过采用多种方法，如不同的培养基组成、各种生长策略和特定的遗传操作，现在可以将细菌培养到超过100 g/L的浓度，并获得高浓度的重组蛋白。虽然生长条件被仔细地监测和维持，但在生长过程中，细胞很可能暴露于由pH值、溶解氧、温度、葡萄糖和盐浓度波动造成的周期性压力条件下。这些压力环境可能发生，特别是在大容量生物反应器中，可能影响生长和生产过程。在过去的几年里，人们已经认识到小的非编码rna可以作为细菌基因表达的调节剂。这些分子被发现专门参与大肠杆菌对不同环境应激条件的反应；但到目前为止，还没有用于改善生产菌株。本文综述了在培养皿或摇瓶培养中发现的可能影响生物反应器中大肠杆菌生长特性的小rna。其中参与响应温度变化的MicC和MicF，响应铁浓度的RyhB，与较低pH相关的gdy，与葡萄糖转运偶联的Sgrs和响应氧浓度的OxyS。本文的最后部分描述了对这些小rna的操纵以促进大肠杆菌在生物反应器中的生长。SgrS的过表达促进了细胞生长，降低了乙酸的表达，GadY的过表达促进了酸性条件下的细胞生长，而OxyS的过表达则降低了氧化应激的影响。操纵srna以改善细胞生长的一个可能的优点是，这些修饰发生在翻译后水平。因此，sRNAs的使用可能对细菌的整体代谢产生最小的影响。新发现的sRNAs的生理作用的阐明将为创造具有更好生长和生产能力的菌株开辟新的可能性。
Efficient growth of E. coli, especially for production of recombinant proteins, has been a challenge for the biotechnological industry since the early 1970s. By employing multiple approaches, such as different media composition, various growth strategies and specific genetic manipulations, it is now possible to grow bacteria to concentrations exceeding 100 g/L and to achieve high concentrations of recombinant proteins. Although the growth conditions are carefully monitored and maintained, it is likely that during the growth process cells are exposed to periodic stress conditions, created by fluctuations in pH, dissolved oxygen, temperature, glucose, and salt concentration. These stress circumstances which can occur especially in large volume bioreactors, may affect the growth and production process. In the last several years, it has been recognized that small non-coding RNAs can act as regulators of bacterial gene expression. These molecules are found to be specifically involved in E. coli response to different environmental stress conditions; but so far, have not been used for improving production strains. The review provides summary of small RNAs identified on petri dish or in shake flask culture that can potentially affect growth characteristics of E. coli grown in bioreactor. Among them MicC and MicF that are involved in response to temperature changes, RyhB that responds to iron concentration, Gady which is associated with lower pH, Sgrs that is coupled with glucose transport and OxyS that responds to oxygen concentration. The manipulation of some of these small RNAs for improving growth of E. coli in Bioreactor is described in the last part of the review. Overexpression of SgrS was associated with improved growth and reduced acetate expression, over expression of GadY improved cell growth at acidic conditions and over expression of OxyS reduced the effect of oxidative stress. One of the possible advantages of manipulating sRNAs for improving cell growth is that the modifications occur at a post-translational level. Therefore, the use of sRNAs may exert minimal effect on the overall bacterial metabolism. The elucidation of the physiological role of newly discovered sRNAs will open new possibilities for creating strains with improved growth and production capabilities.
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影响因子：
11.3
作者：
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通讯作者：
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影响因子：
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