Lorenzo Paloma, Alonso Sergio, Velasco Ana, Díaz Eduardo, García José L, Perera Julián
Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Antonie Van Leeuwenhoek. 2003;84(1):17-24. doi: 10.1023/a:1024432929423.
A broad-host range metabolic cassette has been designed that, under the control of the Ptac promoter, expresses the sytABCD catabolic genes from Pseudomonas sp. Y2, which are responsible for the transformation of styrene into phenylacetic acid (styrene upper pathway). This novel cassette confers to phenylacetic acid-degrading bacteria the ability to grow efficiently on styrene as the sole carbon and energy source. By combining both the sty cassette and the archetypal pWW0 TOL plasmid into the well-known Pseudomonas putida F1 aromatic biodegrader, we have constructed a novel derivative strain that shows one of the largest degradative potentials so far described for aromatic hydrocarbons, because it is able to use BTEX compounds (benzene, toluene, ethylbenzene and xylenes) and styrene as a source of carbon and energy. Furthermore, the sty cassette was engineered within a mini-transposon and endowed with a gene containment system, based on the toxic effect of the colicin E3 RNase, to reduce its lateral spread to other hosts. This contained cassette lacks defined transcriptional regulatory signals and, thus, it becomes an alternative strategy to select recombinant strains that efficiently express the desired phenotype from housekeeping regulatory elements.
已经设计了一种广宿主范围的代谢盒，该代谢盒在Ptac启动子的控制下，表达来自假单胞菌属Y2的sytABCD分解代谢基因，这些基因负责将苯乙烯转化为苯乙酸（苯乙烯上途径）。这种新型代谢盒赋予了苯乙酸降解细菌以苯乙烯作为唯一碳源和能源高效生长的能力。通过将苯乙烯代谢盒和原型pWW0 TOL质粒都整合到著名的恶臭假单胞菌F1芳香族生物降解菌中，我们构建了一种新型衍生菌株，该菌株显示出迄今为止所描述的对芳香烃最大的降解潜力之一，因为它能够利用BTEX化合物（苯、甲苯、乙苯和二甲苯）和苯乙烯作为碳源和能源。此外，苯乙烯代谢盒被设计在一个微型转座子内，并基于大肠杆菌素E3核糖核酸酶的毒性作用配备了一个基因限制系统，以减少其向其他宿主的横向传播。这种受限代谢盒缺乏明确的转录调控信号，因此，它成为一种从管家调控元件中选择能有效表达所需表型的重组菌株的替代策略。
