用绿色荧光蛋白研究军团菌与寄主的相互关系

Use of Green Fluorescent Protein to Study the Relationship between Legionella pneumophila and Its Protozoan Host

原生动物作为军团菌的天然寄主,在军团菌的生存、增殖、毒力和抗逆性等方面起着重要的作用。通过多次转化筛选,获得了一种高量表达绿色荧光蛋白基因gfpmut2的自发突变质粒。该质粒在嗜肺军团菌细胞内稳定复制和表达;转化了该质粒的嗜肺军团菌在自然光下即可发出明亮的绿色荧光。以转化菌饲喂嗜热四膜虫BF1株后,在荧光显微镜下能清楚观察到细菌在细胞内的形态变化、增殖和裂解宿主细胞的过程。为研究嗜肺军团菌与原生动物寄主的相互关系提供了一种简单而直观的方法。

Protozoans, the natural host of the facultative intracellular pathogen LegioneUa species, play an important role in survival, proliferation, virulence and stress resistance of Legionella species. By repeating transformation and selection, a spontaneous mutant of plasmid over expressing green fluorescent protein was obtained. This mutant replicates and is maintained stably in Legionella cells, The colonies of L. pneurnophila harboufing the mutated plasmid were intense green in colour even under the daylight. After feeding BFI strain of Tetrahymena thermophila with transformed L. pneumophila, the intracellular dynamic of changing of bacterial shape, bacterial proliferation and lysis of the host cell due to the bacterial proliferation were observed clearly under fluorescent microscopy. Thus, the present paper provides a simple and intuitionistlc strategy for investigating the ecological and cellular relationship between L. pneurnophila and its host.