Determination of optimum growth conditions for gliotoxin production by Aspergillus fumigatus and development of a novel method for gliotoxin detection

Gliotoxin is a toxic metabolite of Aspergillus fumigatus Fresenius and othe r fungi. It has been suggested that this toxin may play an important role i n the pathogenesis of aspergillosis as gliotoxin has immunosuppressive acti vity both in vitro and in vivo. We have determined the optimum growth condi tions for the production of gliotoxin by selected isolates of ii, fumigatus using a number of defined media. Gliotoxin was detected by thin layer chro matography and high performance liquid chromatography, The carbohydrate sou rce, concentration of carbohydrate in the growth medium and incubation temp erature were all found to influence gliotoxin production. Optimum growth co nditions for gliotoxin production in our study were Czapek-Dox broth contai ning 30% glucose and incubation at 37 degrees C. Most of the gliotoxin was produced after 29 h incubation, during the exponential phase of growth. A n ovel method for screening large numbers of A. fumigatus isolates for glioto xin production, which is both quick and easy, has also been developed, base d on the ability of gliotoxin to inhibit the adherence of lung fibroblast ( L929) cells to plastic microtitre plates.