Fig 9. Effects of nutrients on growth rate.

(A) Cultures of control (csp-1; ras^bd) and NCU05950 deletion mutant (csp-1; ras^bd; NCU05950^KO) were grown on race tubes. Left three sets of columns: Media contained either agar or Phytagel as a gelling agent, and no additional nutrients except Yeast Extract (YE) in one set. Right three sets of columns: Media contained Vogel’s minimal salts plus 2% glucose and 2% agar, and either no nitrogen source (VM no N), casein hydrolysate as nitrogen source (VM no N + casein), or the usual NH₄NO₃ nitrogen source (VM). Values are the mean of 6–9 replicate race tubes and error bars are ± S.E.M. Stars (*) indicate statistically significant difference between control and mutant, p < 0.01. (B) Cultures of wild type or NCU05950 deletion mutant (carrying no additional mutations) were grown in liquid media with Vogel’s minimal medium (VM) and 2% glucose, with or without added NH₄NO₃ and added amino acids. Error bars are mean of four replicate experiments ± S.E.M. Dry weights within each experiment were normalized to the wild-type weight on VM = 1.0. Black stars (*) indicate statistically significant difference between wild type and mutant for the same growth condition, p < 0.05. Colored stars indicate statistically significant difference between growth conditions for the same strain, p < 0.05 (*) or p < 0.01 (**). (C) Effects of glucose concentration on growth rate. Cultures were grown in VM medium with NH₄NO₃ and various concentrations of glucose. Strains as for (B). Error bars are mean of three replicate experiments ± S.E.M. Dry weights within each experiment were normalized to the wild-type weight on 2% glucose = 1.0. Black star (*) indicates statistically significant difference between wild type and mutant, p < 0.05.