Figure 3
A. flavus grown in PMS and GMS media responded differently to the initial spore densities. (A) Higher concentrations of peptone inhibited AF productions in A. flavus A3.2890. P4, PMS media with the initial spore density of 104 spores/ml; P6, PMS media with the initial spore density of 106 spores/ml; G4, cultured in GMS media with the initial spore density of 104 spores/ml; G6, cultured in GMS media with the initial spore density of 106 spores/ml; P4+, PMS media with 15% peptone, cultured with the initial spore density of 104 spores/ml; P6+, PMS media with 15% peptone, cultured with the initial spore density of 106 spores/ml, St, AF standard. (B) Higher concentrations of peptone promoted mycelial growths. The total mycelium dry weights were measured after a 3-day culture, with initial spore densities of 104 or 106 spores/ml. (C) No direct correlations between AF productions and pH changes. In GMS media the pH was gradually decreased during the 55-hr culture, where a higher initial spore density led to faster acidification of the medium. In PMS media the pH was increased during culture, where a higher initial spore density led to rapid alkalization of the medium. Note that increased peptone concentrations did not cause a significant change in the pH of PMS media (P6 and P6+).