Figure 6

Gliotoxin biosynthesis is induced with exogenous gliotoxin addition. A. A significant increase (p =0.0295) in the amount of de novo gliotoxin ([¹³C]-gliotoxin) produced following addition of exogenous gliotoxin was observed compared to the methanol control. B. Time-line of the experimental conditions. Cultures (duplicate) were inoculated at T =0 h. At T =24 h, [¹³C]-phenylalanine was added along with gliotoxin (5 μg/ml final) or methanol (solvent control). Culture supernatants were collected at T =72 h and organic extraction carried out prior to LC-MS/MS analysis. C. Spectrum showing gliotoxin (m/z 327) and [¹³C]-gliotoxin (m/z 328) in cultures spiked with the methanol. D. Spectrum showing gliotoxin (m/z 327) and [¹³C]-gliotoxin (m/z 328) in cultures spiked with exogenous gliotoxin. The black arrows highlight [¹³C]-gliotoxin, where higher levels are observed in cultures induced by exogenous gliotoxin compared to the methanol control.