passages.id: split_1_test_3517_passage
passages.type: progene_text
passages.text: To measure the effects of the deletions on the expression of cpe , translational fusions containing the promoter deletions were made with the gusA gene of Escherichia coli , which codes for beta-glucuronidase ; E. coli-C. perfringens shuttle vectors carrying the fusions were introduced into C. perfringens by electroporation .