Synthesis of versicolorin A by a mutant strain of Aspergillus parasiticus deficient in aflatoxin production

1975 ◽  
Vol 23 (6) ◽  
pp. 1132-1134 ◽  
Author(s):  
Louise S. Lee ◽  
Joan W. Bennett ◽  
Alva F. Cucullu ◽  
James B. Stanley
Keyword(s):  
Mutant Strain ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Versicolorin A

scholarly journals Nonfunctionality of Aspergillus sojae aflR in a Strain of Aspergillus parasiticus with a Disrupted aflR Gene

2002 ◽  
Vol 68 (8) ◽  
pp. 3737-3743 ◽  
Author(s):  
Tadashi Takahashi ◽  
Perng-Kuang Chang ◽  
Kenichiro Matsushima ◽  
Jiujiang Yu ◽  
Keietsu Abe ◽  
...  
Keyword(s):  
Aspergillus Oryzae ◽  
Aspergillus Parasiticus ◽  
Transcription Activation ◽  
Aflatoxin Production ◽  
Activation Domain ◽  
Aspergillus Sojae ◽  
Coding Regions ◽  
Transcription Activation Domain ◽  
Chimeric Construct ◽  
Versicolorin A

ABSTRACT Aspergillus sojae belongs to the Aspergillus section Flavi but does not produce aflatoxins. The functionality of the A. sojae aflR gene (aflRs) was examined by transforming it into an ΔaflR strain of A. parasiticus, derived from a nitrate-nonutilizing, versicolorin A (VERA)-accumulating strain. The A. parasiticus aflR gene (aflRp) transformants produced VERA, but the aflRs transformants did not. Even when aflRs was placed under the control of the amylase gene (amyB) promoter of Aspergillus oryzae, the amy(p)::aflRs transformants did not produce VERA. A chimeric construct containing the aflRs promoter plus the aflRs N- and aflRp C-terminal coding regions could restore VERA production, but a construct containing the aflRp promoter plus the aflRp N- and aflRs C-terminal coding regions could not. These results show that the A. sojae aflR promoter is functional in A. parasiticus and that the HAHA motif does not affect the function of the resulting hybrid AflR. We conclude that the lack of aflatoxin production by A. sojae can be attributed, at least partially, to the premature termination defect in aflRs, which deletes the C-terminal transcription activation domain that is critical for the expression of aflatoxin biosynthetic genes.

Aspergillus parasiticus Accumulates Averufin and Versicolorin A in the Presence of Bicarbonate

1989 ◽  
Vol 52 (7) ◽  
pp. 493-495 ◽  
Author(s):  
ANWAAR EL-NABARAWY ◽  
THOMAS HARTMAN ◽  
JOSEPH D. ROSEN ◽  
THOMAS J. MONTVILLE
Keyword(s):  
Sodium Bicarbonate ◽  
Thin Layer ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Ionization Mass ◽  
Desorption Chemical Ionization ◽  
Norsolorinic Acid ◽  
Solvent Systems ◽  
Versicolorin A ◽  
Abnormal Pigmentation

Sodium bicarbonate has previously been shown to inhibit aflatoxin production by Aspergillus parasiticus. The abnormal pigmentation of colonies grown in the presence of bicarbonate suggested that intermediates of the aflatoxin biosynthetic pathway were accumulating. Aspergillus parasiticus NRRL 2999 cultures grown in the presence of sodium bicarbonate were extracted with acetone and chloroform. Thin layer chromatograms of these extracts were compared to the thin layer chromatograms of extracts from mutant strains which accumulate norsolorinic acid, averufin, and versicolorin A. Development by four separate solvent systems suggested that averufin and versicolorin A accumulated in the bicarbonate-grown wild type cultures. The identity of these intermediates was confirmed by desorption chemical ionization mass spectrometry which showed M+1 peaks of 369 and 339 where M is the molecular weight of averufin and versicolorin, respectively.

Production of Aflatoxin in Cocoa Beans

1979 ◽  
Vol 62 (5) ◽  
pp. 1076-1079 ◽  
Author(s):  
Lawrence M Lenovich ◽  
W Jeffrey Hurst
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Ivory Coast ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Growth Conditions ◽  
Aflatoxin Contamination ◽  
Cocoa Beans ◽  
Total Aflatoxin ◽  
Substrate Variation

Abstract Aflatoxin was produced in both non-autoclaved and autoclaved Ivory Coast cocoa beans inoculated with Aspergillus parasiticus NRRL 2999 under optimum laboratory growth conditions. Total aflatoxin levels ranged from 213 to 5597 ng/g substrate. Aflatoxin was quantitated by using high pressure liquid chromatography (HPLC). Raw, non-autoclaved cocoa beans, also inoculated with aspergilli, produced 6359 ng aflatoxin/g substrate. Variation in aflatoxin production between bean varieties was observed. Total aflatoxin levels of 10,446 and 23,076 ng/g substrate were obtained on Ivory Coast beans inoculated with A. parasiticus NRRL 2999 and NRRL 3240, respectively. Aflatoxin production on Trinidad and Malaysian beans was 28 and 65 ng aflatoxin/g substrate. These data support previously reported low level natural aflatoxin contamination in cocoa.

Antioxidant enzymes stimulation in Aspergillus parasiticus by Lentinula edodes inhibits aflatoxin production

2005 ◽  
Vol 69 (2) ◽  
pp. 207-215 ◽  
Author(s):  
M. Reverberi ◽  
A. A. Fabbri ◽  
S. Zjalic ◽  
A. Ricelli ◽  
F. Punelli ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Lentinula Edodes ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production

Extracts of Agave americana inhibit aflatoxin production in Aspergillus parasiticus

2011 ◽  
Vol 4 (1) ◽  
pp. 37-42 ◽  
Author(s):  
A. Rosas-Taraco ◽  
E. Sanchez ◽  
S. García ◽  
N. Heredia ◽  
D. Bhatnagar
Keyword(s):  
Aspergillus Parasiticus ◽  
Public Awareness ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Aqueous Extracts ◽  
Total Aflatoxin ◽  
Toxigenic Fungi ◽  
Agave Americana ◽  
Acid Accumulation ◽  
Norsolorinic Acid

Toxigenic fungi invade crops prior to harvest as well as during storage and produce harmful, even carcinogenic toxins such as aflatoxins. Since consumers demand safe commodities, and due to enhanced public awareness of the dangers of many synthetic fungicides, the importance of investigating alternative, natural products to control these toxigenic fungi is clear. This study investigated the effect of aqueous extracts of Agave americana on growth, conidia and aflatoxin production. Aspergillus parasiticus strains SRRC 148, SRRC 143 (Su-1), and A. parasiticus SRRC 162, a mutant (nor-) that accumulates norsolorinic acid (NOR, an orange-coloured intermediate of the aflatoxin pathway), were first inoculated into Adye and Mateles liquid medium, then plant extracts were added, and incubated at 28 °C for 7 days. Aflatoxin and norsolorinic acid were assayed by HPLC and spectrophotometry, respectively. While the extract of A. americana stimulated growth of the studied fungi, conidiogenesis, norsolorinic acid accumulation (in the nor- mutant), and aflatoxin production were significantly affected. The reduction was produced by the extracts at concentrations higher than 5-10 mg/ml, where all types of total aflatoxin analysed (aflatoxins B1, B2, G1 and G2) were reduced from 64% to >99% in the whole culture, and a reduction of 75% of norsolorinic acid. The results of the present work indicate that extracts of A. americana may be promising safe alternatives to harmful fungicides for controlling aflatoxin contamination.

Effect of selected inhibitors on growth, pigmentation, and aflatoxin production by Aspergillus parasiticus

1986 ◽  
Vol 94 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Raul Valcarcel ◽  
J. W. Bennett ◽  
Joanne Vitanza
Keyword(s):  
Aspergillus Parasiticus ◽  
Aflatoxin Production

ChemInform Abstract: Blasticidin A as an Inhibitor of Aflatoxin Production by Aspergillus parasiticus

ChemInform ◽  
2001 ◽  
Vol 32 (15) ◽  
pp. no-no
Author(s):  
Shohei Sakuda ◽  
Makoto Ono ◽  
Hiroyuki Ikeda ◽  
Takefumi Nakamura ◽  
Yasuhito Inagaki ◽  
...  
Keyword(s):  
Aspergillus Parasiticus ◽  
Aflatoxin Production
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