Aflatoxins

Abstract

Aflatoxins are toxic and carcinogenic secondary metabolites produced primarily by the filamentous fungi Aspergillus flavus and Aspergillus parasiticus . Aflatoxin biosynthesis is a complex process involving many intermediates and enzymes, which are regulated at multiple levels. Owing to its complexity and importance, scientists from biochemistry, molecular biology and genetics are attracted to the study of its mechanisms of biosynthesis and regulation. These efforts have resulted in significant process in the last decade. We present here a review of the present knowledge of the aflatoxin biosynthetic pathway, pathway enzymes, and the genes encoding these enzymes involved in the conversion of major aflatoxin intermediates. Genes confirmed to be involved in regulation of aflatoxin formation and control of aflatoxin contamination are summarized as well.

Functional Genomics to Improve Meat Quality in Pigs

“…Later, a completed aflatoxin pathway gene cluster was established when a 75 kb DNA sequence was determined (Yu et al 2004a-c). Based on genome sequence data, this aflatoxin gene cluster is located on chromosome III near subtelomeric region (Yu et al 2008(Yu et al , 2010a. The primary evolutionary advantage of gene clustering may be for the purpose of coordinated gene expression.…”

Expression Profiling of Non-Aflatoxigenic Aspergillus parasiticus Mutants Obtained by 5-Azacytosine Treatment or Serial Mycelial Transfer

“…In the absence of veA ,aflatoxins (AFs), the highly toxic hydrophobic secondary metabolites produced by some Aspergillus species [8], are not produced. Null mutants of laeA also are unable to produce AFs and other secondary metabolites.…”

“…A number of studies have shown that conidiophore development and secondary metabolism are co-regulated [ 4 , 5 , 6 , 7 ]. In the absence of veA ,aflatoxins (AFs), the highly toxic hydrophobic secondary metabolites produced by some Aspergillus species [ 8 ], are not produced. Null mutants of laeA also are unable to produce AFs and other secondary metabolites.…”