ABSTRACT
Contamination .................................................................................. 370 15.3.3 A¯atoxin Biosynthetic Pathway........................................................ 371 15.3.4 A¯atoxin Biosynthetic Pathway Genes ............................................ 372 15.3.5 A¯atoxin Biosynthetic Pathway Gene Cluster.................................. 374 15.3.6 Genetic Regulation of A¯atoxin Biosynthesis .................................. 374
15.3.6.1 Positive Regulatory Gene a”R ........................................... 374 15.3.6.2 Co-Regulatory Gene a”S (Old Name a”J) ........................ 375 15.3.6.3 Global Regulatory Gene laeA ............................................ 375 15.3.6.4 Developmental Regulatory Gene veA ................................ 376
15.3.7 Factors Affecting A¯atoxin Biosynthesis ......................................... 376 15.3.7.1 Carbon ................................................................................ 376 15.3.7.2 Nitrogen ............................................................................. 377 15.3.7.3 Temperature ....................................................................... 377 15.3.7.4 Water Activity .................................................................... 378 15.3.7.5 Culture pH ......................................................................... 378 15.3.7.6 Developmental Stage ......................................................... 378 15.3.7.7 Oxidative Stress ................................................................. 379 15.3.7.8 Plant Metabolites ............................................................... 379
In the fungal kingdom, Aspergilli belong to the class of imperfect ›lamentous fungi. Among the roughly 250 known species, many are capable of producing a broad array of bene›cial secondary metabolites (Du’Lock 1965), such as antibiotics and other pharmaceuticals (Brakhage et al. 2008). For example, Aspergillus terreus produces lovastatin, a potent cholesterol-lowering drug. Other Aspergilli are used to produce antibiotics (penicillin and cephalosporin), antifungals (griseofulvin), and antitumor drugs (terrequinone A) (Hoffmeister and Keller 2007, Keller et al. 2005). There are many more uncharacterized compounds produced by Aspergilli through various metabolic pathways. These compounds include pathway end products and pathway intermediates or shunt metabolites formed along these pathways and may also have bene›cial pharmaceutical properties that can be a potential source of new drugs.
