Using chromosome DNA of Lactobacillus casei 34103 as template, thy A (Thymidylate synthase) gene was amplified by PCR with pfu DNA polymerase.

• 以干酷乳杆菌L.；casei34103染色体DNA为模板，利用PCR技术扩增胸苷酸合成酶(Thymidy-1atesynthase，fhyA)基因，回收纯化。