Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract only
Publication Acceptance Date: 4/21/2006
Publication Date: 5/21/2006
Citation: Wilkinson, J.R., Yu, J., Bland, J.M., Scheffler, B.E., Kim, H.S., Nierman, W.C., Cleveland, T.E. 2006. Influence of tryptophan on aflatoxin biosynthesis and regulation in Aspergillus flavus. In: Proceedings of the American Society for Microbiology Annual Meeting, May 21-26, 2006, Orlando, FL. Abstract #O-042, p. 429. Interpretive Summary:
Technical Abstract: Aflatoxins are extremely toxic and carcinogenic compounds produced primarily by the fungi Aspergillus flavus and A. parasiticus. Molecular studies on the genetics of aflatoxin biosynthesis established a well organized aflatoxin pathway gene cluster consisting of 25 genes within 70 kb DNA region. Many nutritional and environmental factors are found to affect aflatoxin formation. The effects on aflatoxin biosynthesis in A. flavus and A. parasticus grown in yeast extract sucrose medium were compared to yeast extract sucrose media supplemented with tryptophan. Yeast extract sucrose media supplemented with tryptophan was found to significantly reduce total aflatoxin B1 and B2 in A. flavus, but significantly increased B1 and G1 in A. parasiticus. Microarray analysis of the effects of tryptophan on aflatoxin regulation was performed. Preliminary analysis of A. flavus revealed that several genes within the aflatoxin biosynthetic pathway gene cluster have decreased expression in the presence of tryptophan. More complete analysis of gene transcription profiles are planned to better characterize the effects of tryptophan on regulation of aflatoxin biosynthesis.