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Some bacteria have adapted to super cold environments for millions of years. And scientists have isolated some of the essential genes that allow bacteria to tolerate their harsh living conditions—because these same genes might help in the creation of new vaccines. The investigators published their findings in the Proceedings of the National Academy of Sciences.
Researchers from the University of Victoria in British Columbia isolated temperature-sensitive genes from some bacteria that thrive in the ___1___. They inserted nine of these cold-loving genes into a bacterial pathogen called Francisella tularensis. At about room temperature, the cells propagated. But when they had to cope with warmth equivalent to the ___2___ body temps of mammals, the bacteria died.
So the scientists injected these ___3___ pathogens into rats and mice at cool parts of the body, such as the ___4___ regions of the ear and the base of the tail. The bacteria survived near the skin, but perished ___5___ reaching the internal organs. And before they expired, the bacteria generated a protective immune response in the animals. The scientists hope to use this tool to create live vaccines that will confer immunity—before they die from our too warm welcome.
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有些细菌已在极端寒冷的环境中生存了上百万年，科学家从这些细菌中分离出能使生物适应严酷环境的重要基因，用以帮助生产新的疫苗。其研究成果发表于《美国国家科学院院刊》。（作者巴里·迪普兰迪斯等，VUWp） 不列颠哥伦比亚省维多利亚大学的研究人员从生活在严寒北极地区的细菌中提取出热敏基因，将其中就中嗜冷基因注入细菌性病原体土拉杆菌内。室温条件下，土拉杆菌细胞增殖了。但当温度上升到与哺乳动物内脏器官的温度相当时，土拉杆菌便开始死亡。 于是科学家将这些经过基因改造的病原体注入鼠的体内，他们选择鼠耳肥厚处、尾巴根部等温度较低的地方进行了注射。土拉杆菌在鼠的体表周围生存了下来，但在侵入内部器官之前便已死亡。细菌死亡前在鼠体内触发了保护性免疫反应。科学家希望采取这样的方式研制出提升机体免疫力的活疫苗，当然，得想办法让这种活疫苗不会因为我们身体太过“热”烈的欢迎而死去。