FIG 1.

Growth curves of S. mutans wild type and mutant strains with levan as the sole carbohydrate source. (A) Growth of the WT UA159 and mutants deficient in fruA, fruB or both. (B) A WT copy of fruB gene was cloned into a shuttle vector pIB184 and the resultant plasmid was introduced into △fruB (△fruB^c). An empty pIB184 was introduced into △fruB background to serve as a vector control (ΔfruB^c-vector). (C) WT and three mutant strains were supplemented with purified 100 nM recombinant protein rFruB. Data are representative of three independent experiments performed at least in triplicate.