Sterigmatocystin (ST) is a carcinogenic polyketide produced by several filamentous fungi including Aspergillus nidulans. Expression of ST biosynthetic genes (stc genes) requires activity of a Zn(II)2Cys6 transcription factor, AflR. aflR is transcriptionally and post-transcriptionally regulated by a G-protein/cAMP/protein kinase A (PkaA) signaling pathway involving FlbA, an RGS (regulator of G-p...

Aflatoxin contamination of foods and feeds is a world-wide agricultural problem. Aflatoxin production requires expression of the biosynthetic pathway regulatory gene, aflR, which encodes a Cys6Zn2-type DNA-binding protein. Homologs of aflR from Aspergillus nomius, bombycis, parasiticus, flavus, and pseudotamarii were compared to investigate the molecular basis for variation among aflatoxin-prod...

The filamentous fungus Aspergillus nidulans contains a cluster of 25 genes that encode enzymes required to synthesize a toxic and carcinogenic secondary metabolite called sterigmatocystin (ST), a precursor of the better known fungal toxin aflatoxin (AF). One ST Cluster (stc) gene, aflR, functions as a pathway-specific transcriptional regulator for activation of other genes in the ST pathway. Ho...

Objective: Aflatoxin is known as one of the most important mycotoxins that threatens of human life. The toxin is produced by Aspergillus species which are common cause of contamination of agricultural products. For this reason, the use of organic compounds has always been considered in order to inhibit the growth of fungi and production of toxin. The aim of this study was to investigate the eff...

background: the effect of probiotic bacteria ( lactobacillus acidophilus and l. casei ) as safe organisms was examined on fungal growth and aflatoxin gene regulation in aspergillus parasiticus . methods: the fungus was cultured in presence of two different concentrations of l. acidophilus and l. casei in mrs broth medium. mycelia dry weight is indicated as criteria to evaluate fungal growth. be...

To help assess the potential for aflatoxin production by Aspergillus oryzae, the structure of an aflatoxin biosynthesis gene homolog cluster in A. oryzae RIB 40 was analyzed. Although most genes in the corresponding cluster exhibited from 97 to 99% similarity to those of Aspergillus flavus, three genes shared 93% similarity or less. A 257-bp deletion in the aflT region, a frameshift mutation in...

The aim was to decipher the temporal impact of key interacting climate change (CC) abiotic factors temperature (30 vs 37 °C), water activity (aw; 0.985 0.930) and CO2 exposure (400 1000 ppm) on (a) growth Aspergillus flavus effects (b) gene expression a structural (aflD) regulatory (aflR) involved in aflatoxin B1 (AFB1) biosynthesis (c) AFB1 production yeast extract sucrose medium over period 1...

The transcription factor AflR is required for up-regulation of specific pathway genes involved in aflatoxin biosynthesis in the filamentous fungus Aspergillus. nor-1 encodes an early aflatoxin pathway enzyme; its promoter contains a consensus AflR binding site (AflR1). Proteins in Aspergillus parasiticus cell extracts and AflR expressed in Escherichia coli do not bind to A. parasiticus AflR1 in...