Bdellovibrio bacteriovorus is a predatory bacterium that feeds on Gram-negative bacteria including a wide range of pathogens and thus has potential applications as a biocontrol agent. Owing to its unique life cycle, however, there are limited tools that enable genetic manipulation of B. bacteriovorus. This work describes our first steps toward engineering the predatory bacterium for practical applications by developing basic genetic parts to control gene expression. Specifically, we evaluated four robust promoters that are active during the attack phase of B. bacteriovorus. Subsequently, we tested several synthetic riboswitches that have been reported to function in Escherichia coli, and identified theophylline-activated riboswitches that function in B. bacteriovorus. Finally, we inserted the riboswitch into the bacterial chromosome to regulate expression of the flagellar sigma factor fliA, which was previously predicted to be essential for predation, and observed that the engineered strain shows a faster predation kinetics in the presence of theophylline.

中文翻译：

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控制噬菌蛭弧菌基因表达和捕食使用合成核糖开关

Bdellovibrio bacteriovorus是一种捕食性细菌，以包括多种病原体的革兰氏阴性细菌为食，因此具有潜在的生物防治作用。然而，由于其独特的生命周期，仅有有限的工具能够对细菌噬菌芽孢杆菌进行基因操作。这项工作描述了我们通过开发基本的遗传部分来控制基因表达而将捕食性细菌工程化以用于实际应用的第一步。具体而言，我们评估了四个强大的启动子，它们在B. bacteriovorus的攻击阶段具有活性。随后，我们测试了几种合成的核糖开关，据报道它们在大肠杆菌中起作用，并确定了在茶孢杆菌中起作用的茶碱激活的核糖开关。最后，我们将核糖开关插入细菌染色体中，以调节鞭毛sigma因子fliA的表达，这以前被认为是捕食必不可少的，并且观察到工程菌株在茶碱存在下显示出更快的捕食动力学。