MacCormick C A, Griffin H G, Gasson M J
Institute of Food Research, Colney, Norwich, UK.
FEMS Microbiol Lett. 1995 Mar 15;127(1-2):105-9. doi: 10.1111/j.1574-6968.1995.tb07457.x.
A plasmid-based food-grade vector system was developed for Lactococcus lactis by exploiting the genes for lactose metabolism. L. lactis MG5267 is a plasmid-free strain containing the entire lactose operon as a chromosomal insertion. The lacF gene was deleted from this strain by a double cross-over homologous recombination event. The lacF-deficient strain produced a Lac- phenotype on indicator agar. A cloned copy of the lacF gene expressed on a plasmid was capable of complementing the lacF-deficient strain resulting in a Lac+ phenotype. This stably maintained system fits the requirements of a self-selecting vector system and has the potential to be exploited in the food industry.
通过利用乳糖代谢基因，开发了一种基于质粒的食品级乳酸乳球菌载体系统。乳酸乳球菌MG5267是一种无质粒菌株，其含有作为染色体插入片段的完整乳糖操纵子。通过双交换同源重组事件从该菌株中缺失了lacF基因。lacF缺陷型菌株在指示琼脂上表现出Lac-表型。在质粒上表达的lacF基因的克隆拷贝能够互补lacF缺陷型菌株，从而产生Lac+表型。这种稳定维持的系统符合自选择载体系统的要求，并且具有在食品工业中得到应用的潜力。
