实验一:肺炎球菌的转化实验 1928年, Fred griffith肺炎球菌( Pneumococcus Ca)strain kills mouse+ Live mouse -Dead mouse (b)R strain does not kill mouse t live mouse- live mouse (c) head-killed S strain does not kill mouse t live mouse-Live mouse (d)R strain plus heat-killed S strain, both of which are separately nonlethal, kill mouse t live mouse-Dead mouse实验一：肺炎球菌的转化实验 • 1928年，Fred Griffith 肺炎球菌（Pneumococcus） （a）S strain kills mouse+ Live mouse →Dead mouse （b） R strain does not kill mouse + live mouse→ live mouse （c） Head—killed S strain does not kill mouse + live mouse→Live mouse （d） R strain plus heat—killed S strain，both of which are separately nonlethal，kill mouse + live mouse→Dead mouse