Predicted Roles of the Uncharacterized Clustered Genes in Aflatoxin Biosynthesis

Ehrlich, Kenneth C.

doi:10.3390/toxins1010037

Cited by 62 publications

(74 citation statements)

References 87 publications

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“…This may affect gene products required in catalysis of any important intermediate precursors in aflatoxin production. This is similar to the report of Ehrlich (2009) in oxidation of norsolorinic acid anthrone to averantin. Lack of aflS transcript in aflS-knockout mutants of A. parasiticus was also revealed by Yu (2012), to be associated with 5-20 fold reduction of expression of some aflatoxin pathway specific genes, such as aflC (pksA), aflD (nor-1), aflM (ver-1) and aflP (omtA).…”

Section: Discussionsupporting

confidence: 92%

Effects of Radiation and Chemical Mutagenesis on Expression of Aflatoxigenic Traits in Aspergillus parasiticus SMS08-C

Ekundayo¹,

Juwon²

2015

Research J. of Microbiology

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The study presented the effects of some chemical and radiation mutagens on aflatoxigenic traits in Aspergillus parasiticus SMS08-C. This was an attempt to enhance its bio-reagent standard production potential and repress aflatoxins production as a control measure. The fungal spores were suspended into fixed concentrations of sodium azide (NA), Ethyl Methane Sulphonate (EMS), nitrous oxide (HNO), hydroxylamine (NH 2 OH) and some exposed to ultra violet rays (UV) over a period of 90 min. Mutants were recovered at every 15 min of the treatment. The mutants were then screened for aflatoxins in yeast extract sucrose medium (pH 5.5) at 30°C for 10 days in the dark. Aflatoxin analysis was carried out using ELISA-based techniques. The effects of the mutagens were significantly different on expression of aflatoxigenic traits (p<0.05). Substantial reduction in aflatoxin production was showed by mutants listed with the corresponding percentage, TM EMS mutagens as tools in improving biotechnological potentials of Aspergillus parasiticus either to repress or promote aflatoxins biosynthesis has been revealed.

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Section: Discussionsupporting

confidence: 92%

Effects of Radiation and Chemical Mutagenesis on Expression of Aflatoxigenic Traits in Aspergillus parasiticus SMS08-C

Ekundayo¹,

Juwon²

2015

Research J. of Microbiology

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“…It is not a DNA binding protein; however, according to Chang (2003), it interacts with aflR and somehow supports DNA binding by the latter. Ehrlich (2009) recently discussed that aflS may interact with the global secondary metabolite regulatory factor laeA. According to a recent analysis of Du et al (2007), aflS appears to modulate the activity of aflR.…”

Section: Discussionmentioning

confidence: 99%

The production of aflatoxin B1 or G1 by Aspergillus parasiticus at various combinations of temperature and water activity is related to the ratio of aflS to aflR expression

et al. 2010

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The influence of varying combinations of water activity (aw) and temperature on growth, aflatoxin biosynthesis and aflR/aflS expression of Aspergillus parasiticus was analysed in the ranges 17-42°C and 0.90-0.99 aw. Optimum growth was at 35°C. At each temperature studied, growth increased from 0.90 to 0.99 aw. Temperatures of 17 and 42°C only supported marginal growth. The external conditions had a differential effect on aflatoxin B1 or G1 biosynthesis. The temperature optima of aflatoxin B1 and G1 were not at the temperature which supported optimal growth (35°C) but either below (aflatoxin G1, 20-30°C) or above (aflatoxin B1, 37°C). Interestingly, the expression of the two regulatory genes aflR and aflS showed an expression profile which corresponded to the biosynthesis profile of either B1 (aflR) or G1 (aflS). The ratios of the expression data between aflS:aflR were calculated. High ratios at a range between 17 and 30°C corresponded with the production profile of aflatoxin G1 biosynthesis. A low ratio was observed at >30°C, which was related to aflatoxin B1 biosynthesis. The results revealed that the temperature was the key parameter for aflatoxin B1, whereas it was water activity for G1 biosynthesis. These differences in regulation may be attributed to variable conditions of the ecological niche in which these species occur.

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“…This "leaky" phenotype is found with the following knockout mutants: nor-1, adhA, hypB1 or hypB2, norA, norB, and ordB. This suggests that gene homologs inside or outside of the cluster encode proteins that are able to substitute for the catalytic function of these Nidulans/Flavus-type cluster proteins (Ehrlich 2009). Why are gene clusters maintained?…”

Section: Evolution Of the Aflatoxin Gene Clustermentioning

confidence: 98%

The Population Dynamics of Aflatoxigenic Aspergilli

Moore¹,

Beltz²,

Carbone³

et al. 2011

Aflatoxins - Biochemistry and Molecular Biology

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Predicted Roles of the Uncharacterized Clustered Genes in Aflatoxin Biosynthesis

Cited by 62 publications

References 87 publications

Effects of Radiation and Chemical Mutagenesis on Expression of Aflatoxigenic Traits in Aspergillus parasiticus SMS08-C

Effects of Radiation and Chemical Mutagenesis on Expression of Aflatoxigenic Traits in Aspergillus parasiticus SMS08-C

The production of aflatoxin B1 or G1 by Aspergillus parasiticus at various combinations of temperature and water activity is related to the ratio of aflS to aflR expression

The Population Dynamics of Aflatoxigenic Aspergilli

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