FIG 1 .
Prioritization of carbohydrate catabolism in V. fischeri. (A) The effects of deletions of genes encoding PTS proteins (NagE1, NagE2, and crr) on growth yield with chitin sugars, aminosugars, or non-PTS carbohydrates as substrates. The percent cell yield (based on the culture OD600), relative to that for the wild type, was calculated following 24 h of growth in a minimal medium containing 30 mM of one of seven sole carbon sources (n = 2): (GlcNAc)2, chitobiose; GlcNAc, N-acetylglucosamine; GlcN, glucosamine; NANA, N-acetylneuraminic acid. Sugars shown in the gray box are PTS-transported sugars that require EIIAcrr (Ccr). (B and C) Relative promoter activity for the glpFK locus during growth in a tryptone-based medium in the absence or presence of glycerol (B) or a glycerol- and tryptone-containing medium in the absence or presence of GlcNAc (C) (n = 2; results shown are representative of two independent experiments). (D) Effect of GlcNAc addition on the rate of glycerol consumption by V. fischeri wild-type and mutant strains (n = 3). a, b, and c indicate statistically different mean values, determined by a two-way analysis of variance with post hoc Bonferroni t tests. Error bars indicate standard errors.