FIG. 1.
Maps of constructed food-grade vectors. Relevant restriction enzyme sites are shown. (A) pBSt1 was constructed with pBUL1 by using thyASt as a selection marker. White arrow, replication (rep.) protein gene of pBUL1. (B) pSLb1 was constructed with pSY1 by using thyALb as a selection marker. White arrow, replication protein gene of pSY1. (C) A food-grade integration vector, pSintA1, which has a ts ori (repAts), thyALb as a selection marker (black arrow), and amyA as a foreign gene (dotted arrow). thyALb and amyA are inserted between two DNA fragments, lac-1 (striped box with a superimposed arrow) and lac-2 (stippled box with a superimposed arrow), derived from the lacZ gene of S. thermophilus. The lacZ gene was selected as an integration target site. Relevant restriction enzyme sites are shown.