肺炎双球菌转化试验: 肺炎链球菌 感染小鼠 S型菌体 小就死少 死S型菌体 四a R型菌体 死小鼠体内有S型菌体 死S型菌体 舌R型菌体 8 提取S型菌体DNA 1928年,Grth 与R型活菌体混合 转化 S型菌体
肺炎双球菌转化试验： 1928年, Griffith
Mature Ta phage
噬菌体感染图象
噬菌体感染图象
T2噬菌体 E coli 噬菌体外亮 搅拌器 SS 噬菌体外壳 9 doq? 搅拌器 多 图10-2噬菌体的感染,证明DNA是遗传物质。 上:噬菌体T2用s标记,大多数放射性在细菌外面
Protein Phage DNA Tail fibers 1 Phage T2(unlabeled) Attachment of phage tail Phage added to E coli fibers to bacterial wall in radioactive medium Phage genetic material (? is injected into bacteria Progeny phages Replication of DNA; synthesis of protein coats and tails Phage genetic material directs y synthesis of phage components unlabeled bacteria Components accumulate; assembly of ges and cell lysis hosts" from arterial cell Phage"gho Infected bacterium are labeled with Infected bacterium are unlabeled Viable phage produced labeled with Viable unlabeled phage produced New phages released