passages.id: split_6_test_1166_passage
passages.type: progene_text
passages.text: The introduction of a Shine - Dalgarno sequence upstream of each initiation codon of the phdABCD genes improved their expression in E. coli. E. coli cells carrying phdBCD or phdACD exhibited no phenanthrene - degrading activity , and those carrying phdABD or phdABC exhibited phenanthrene - degrading activity which was significantly less than that in cells carrying the phdABCD genes .