passages.id: split_1_test_493_passage
passages.type: progene_text
passages.text: The genes encoding PBPs 1a , 1b , 4 , 5 , 6 , and 7 , AmpC , and AmpH were cloned , and from each gene an internal coding sequence was removed and replaced with a kanamycin resistance cassette flanked by two res sites from plasmid RP4 .