Nine replicates for each treatment.
Table 1 Metabolites with significant differences between mycelia of A. flavus grown in media with or without D-glucal eFT-508 supplier (40 mg/mL) Compoundsa Relative peak areab Fold increasec P valued Control D-glucal Organic acids Furanacetic acid 0.0184 ± 0.0039 2.9291 ± 0.2771 159.10 <0.01 Kojic acid 0.0942 ± 0.0333 0.2076 ± 0.0293 2.20 <0.01 Sugar metabolism Ribitol 0.0066 ± 0.0038 0.0168 ± 0.0051 2.56 <0.01 Glycerol 0.0219 ± 0.0055 0.0514 ± 0.0350 2.34 <0.01 D-glucose 0.0133 ± 0.0060 0.1233 ± 0.0400 9.27 <0.01 D-galactose 0.0317 ± 0.0096 0.1750 ± 0.0743 5.53 <0.01 TCA intermediates Succinic acid 0.0053 ± 0.0016 0.0020 ± 0.0005 0.37 <0.01 Malic acid 0.0023 ± 0.0013 ND ND ND Fumaric acid 0.0003 ± 0.0001
0.0002 ± 0.0000 0.53 <0.01 Fatty acids Palmitic acid 0.1428 ± 0.0116 0.0856 ± 0.0144 0.60 <0.01 Stearic acid 0.0702 ± 0.0150 0.0468 ± 0.0072 0.66 <0.01 Oleic acid 0.1957 ± 0.0159 0.0377 ± 0.0093 0.19 <0.01 Linoleic acid 0.2647 ± 0.0219 0.1281 ± 0.0212 0.48 <0.01 Others Glycine 0.0010 ± 0.0004 0.0004 ± 0.0002 0.39 <0.01 Pyrimidine 0.0018 ± 0.0005 0.0009 ± 0.0001 A 769662 0.53 <0.01 aIndividual metabolites were identified by GC-TOF MS, as described in the Methods. bRelative peak area as normalized to the peak area of heptadecanoic acid. cFolds represents the relative peak areas in D-glucal-treated samples/peak areas in the control. dStatistical differences between check details control and D-glucal treated samples were calculated by two-tailed Student’s t-test. N.D.: not detected. We next cultured A. flavus A 3.2890 in GMS
media with or without 40 mg/mL D-glucal, and measured kojic acid contents in media using a colorimetric method [19]. During the 5-d culture period the kojic acid contents in media with D-glucal were always higher (about 4 to 5 folds) than the control (Figure 4A). We also measured glucose content in the media and observed that, in the presence of D-glucal, the glucose content on the 4th and the 5th d were about 30% higher than those in the control media lacking D-glucal, suggesting that exogenous D-glucal inhibited the consumption of glucose (Figure 4B). Figure 4 Effects of D-glucal on kojic acid production, glucose consumption and NOR accumulation. (A) Production of kojic acid by A. flavus grown in GMS media with or without 40 mg/mL D-glucal. Values are presented as means ± S.D. (n = 3), from three independent experiments. (B) Glucose contents in media at different time points when cultured in the presence of 40 mg/mL D-glucal. (C) D-glucal inhibited NOR accumulation. The amount of NOR in GMS medium lacking D-glucal was set to 1, those in other samples were calculated accordingly. Values are presented as means ± S.D. (n = 3). D-glucal inhibited NOR production We used the A. flavus strain Papa 827 to decipher at which step D-glucal inhibits AF biosynthesis.