• Journal of Food Hygiene and Safety
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• v.10 no.1
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• pp.1-6
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• 1995

In order to establish the enzyme linked immunosorbent assay(ELISA) of sterigmatocystin produced by Aspergillus versicolor, we experimented and obtained following results. Two of three rabbits which had been immunized with sterigmatocystin-hemiacetal-BSA produced antibodies against sterigmatocystin at 15 weeks. The produced antibodies were specific for sterigmatocystin and sterigmatocystin-hemiacetal but didn't cross react with other sterigmatocystin analogues in a significant degree. DMF : 4% KC1 (18 : 2) mixed solution was most effective to dissolve sterigmatocystin. For the preparation of sample solution to determine sterigmatocystin by ELISA, sample was extracted with CHC13 and dried, than the dried sample was redissolved with 100 ${mu}ell$ DMF + 4% KC1 mixture. 10~1,000 ng/$m\ell$ level of standard sterigmatocystin could be applied to the established ELISA. When artifically contaminated rice were assayed by the ELISA, the average recovery of sterigmatocystin spiked to 25~500 ng/g was 109% (97~116%), and mean interwell coefficient of variation was 21% (11~28%).

• The Korean Journal of Mycology
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• v.14 no.1
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• pp.61-70
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• 1986

Sterigmatocystin bears a close structural relationship to aflatoxin $B_1$ and is a carcinogenic compound that has been shown to affect various species of experimental animals. Reaction and toxicity of sterigmatocystin in the artificial gastric juice were investigated. Sterigmatocystin was degraded in artificial gastric juice and extracted by the method of A.O.A.C. After cleaned up by silica gel column chromatography, this substance was detected and characterized by thin layer chromatography, UV, IR and mass spectra. It showed $R{\mathcal{f}}$ 0.4 and brick-red color by TLC. Especially, in the mass spectrum of it, fragment peak at m/e 327 was due to the loss of the $-CH_3$ and $-H_2O$, fragment peak at m/e 341 was due to the loss of the $H_2O$ and $-H^+$, and fragment peak at m/e 239 was due to the loss of the 2-chloro-tetrahydrofuran and methyl group from the parent molecule. Therefore, a degraded substance of sterigmatocystin reacted in artificial gastric juice (Sub. K) was estimated with additional formation of hydrochloric acid. In four-day-old chicken embryos, the mean lethal dose $(LD_{50})$ was $140\;{\mu}g/egg$, and 90 to 100% of the embryos were killed with 1 mg/egg. This $LD_{50}$ $140\;{\mu}g/egg$ compared with an $LD_{50}$ $14.69\;{\mu}g/egg$ for sterigmatocystin (acute toxicity) showed the substance to be much less toxic than sterigmatocystin.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.1
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• pp.51-58
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• 1996

The effects of allylisothiocyanate on the biosynthesis of various fungus metabolites such as sterigmatocystin, lipid, protein, citrate RNA and AMP from the culture of Aspergillus Parasiticus R-716 were investigated. The content of sterigmatocystin, the precursor of aflatoxin, was lower in the culture added with 50ppm allylisothicoyanate after 48 hours, however was rather higher after 144 hours compared to that of the control. The addition of allylisothiocyanate resulted in the increase of lipid, protein, RNA in mycelium and the content of citrate in the media, but the amount of AMP was low.

• Journal of Microbiology and Biotechnology
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• v.31 no.5
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• pp.676-685
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• 2021

RNA-binding proteins are involved in RNA metabolism and posttranscriptional regulation of various fundamental biological processes. The PUF family of RNA-binding proteins is highly conserved in eukaryotes, and its members regulate gene expression, mitochondrial biogenesis, and RNA processing. However, their biological functions in Aspergillus species remain mostly unknown in filamentous fungi. Here we have characterized the puf genes in the model organism Aspergillus nidulans. We generated deletion mutant strains for the five putative puf genes present in the A. nidulans genome and investigated their developmental phenotypes. Deletion of pufA or pufE affected fungal growth and asexual development. pufA mutants exhibited decreased production of asexual spores and reduced mRNA expression of genes regulating asexual development. The pufE deletion reduced colony growth, increased formation of asexual spores, and delayed production of sexual fruiting bodies. In addition, the absence of pufE reduced both sterigmatocystin production and the mRNA levels of genes in the sterigmatocystin cluster. Finally, pufE deletion mutants showed reduced trehalose production and lower resistance to thermal stress. Overall, these results demonstrate that PufA and PufE play roles in the development and sterigmatocystin metabolism in A. nidulans.

• Mycobiology
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• v.35 no.2
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• pp.47-53
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• 2007

The prevalence and population density of the mycobiota of 50 samples belonging to 10 kinds of spices (anise, black pepper, red pepper, black cumin, peppermint, cardamom, clove, cumin, ginger and marjoram) which collected from different places in Jeddah Governorate were studied. The natural occurrence of mycotoxins in those samples was also investigated. Fifteen genera and thirty-one species of fungi in addition to one species variety were isolated and identified during this study. The most common genera were Aspergillus, Penicillium and Fusarium. Aflatoxins ($12{\sim}40\;{\mu}g/kg$) were detected in the extract of 5 samples of each of anise seeds and black pepper fruits; three samples of black cumin seeds and on sample only of each of peppermint and marjoram leaves out of 5 samples tested of each. Sterigmatocystin ($15{\sim}20\;{\mu}g/kg$) was detected in some samples of red pepper, cumin and marjoram. The inhibitory effects of 10 kinds of powdered spices were tested against 3 toxigenic isolates of fungi (Aspergillus flavus, A. versicolor and Penicillium citrinum). Clove proved to be antimycotic compounds. It inhibited the growth of the tested toxigenic fungi. Black pepper, peppermint, cardamom, cumin and marjoram completely inhibited aflatoxins production, while black pepper and cardamom also completely inhibited sterigmatocystin production.

• Mycobiology
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• v.49 no.5
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• pp.498-506
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• 2021

An endophytic fungus strain DYSJ3 was isolated from a stem of Aphanamixis grandifolia Blume, which was identified as Aspergillus versicolor based on the morphological characteristics, internal transcribed spacer (ITS) and calmodulin gene sequences analyses. A. versicolor DYSJ3 exhibited strong antagonistic activity against Colletotrichum musae, C. gloeosporioides and Fusarium oxysporum f. sp. cubense with the inhibition rates of 61.9, 51.2 and 55.3% respectively. The antifungal metabolites mainly existed in the mycelium of A. versicolor DYSJ3, and its mycelial crude extract (CE) had broad-spectrum antifungal activities against plant pathogenic fungi. The CE had a good thermal stability, and the inhibition rate of 100 mg/mL CE against C. musae was above 70.0% after disposing at 120 ℃ for 1 h. Five secondary metabolites were isolated from the CE and identified as averufanin, ergosterol peroxide, versicolorin B, averythrin and sterigmatocystin. Activity evaluation showed versicolorin B exhibited inhibitory effects on the mycelial growth and conidial germination of C. musae, and sterigmatocystin had a weak inhibitory effect on the mycelial growth of C. musae.

• Mycobiology
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• v.49 no.3
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• pp.258-266
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• 2021

The velvet regulators VosA and VelB are primarily involved in spore maturation and dormancy. Previous studies found that the VosA-VelB hetero-complex coordinates certain target genes that are related to fungal differentiation and conidial maturation in Aspergillus nidulans. Here, we characterized the VosA/VelB-inhibited developmental gene vidD in A. nidulans. Phenotypic analyses demonstrated that the vidD deleted mutant exhibited defect fungal growth, a reduced number of conidia, and delayed formation of sexual fruiting bodies. The deletion of vidD decreased the amount of conidial trehalose, increased the sensitivity against heat stress, and reduced the conidial viability. Moreover, the absence of vidD resulted in increased production of sterigmatocystin. Together, these results show that VidD is required for proper fungal growth, development, and sterigmatocystin production in A. nidulans.

• Journal of Food Hygiene and Safety
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• v.7 no.1
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• pp.15-22
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• 1992

This study was conducted to determine the potential of grapefruit seed extract to support Aspergillus parasilicus growth and aflatoxin production. The grapefruit seed extract inhibited the growth and aflatoxin production of the fungi in the level of more than 4,000 ppm and 3,000 ppm in the medium, respectively. Grapefruit seed extract appears to block the conversion of acetate, averufin and versiconal acetate into aflatoxin in vitro experiments. The addition of grapefruit seed extract to the feeding experiment systems did not inhibit the incorporation of 14C-labeled versicolorin A, versicolorin A hemiacetal and sterigmatocystin into aflatoxin. In the electron microscopic examination the biocidal action of grapefruit seed extract was related to the disturbance of cell menbrane funtion, inhibiting cellular respiration.

• Mycobiology
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• v.50 no.1
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• pp.96-98
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• 2022

The Aspergilli of the section Nidulantes series Versicolores are among the most recurrent molds in indoor environments. These species cause damage to the quality of air. Indeed, they are responsible for allergies, aggravation of asthma and can even cause infections in immunocompromised patients. Molds belonging to the Versicolores series also produce sterigmatocystin, a mycotoxin classified as potential human carcinogen by the International Agency for Research on Cancer (group 2B). Here, we provide for the first time the genome of three species of the series Versicolores: Aspergillus creber, Aspergillus jensenii and Aspergillus protuberus which are the most abundant species of this series in bioaerosols. The genomes of these three species could be assembled with a percentage of completeness of 97.02%, 96.21% and 95.35% for Aspergillus creber, A. jensenii and A. protuberus respectively. These data will allow to study the genes and gene clusters responsible for the expression of virulence factors, the biosynthesis of mycotoxins and the proliferation of these ubiquitous and recurrent molds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.278-286
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• 1987

The results in vestigated produced fluorescence compounds and mycotoxins, studied stability and toxicity of these compounds which were isolated from varicous moistured rice culture extacts inoculated Aspergillus versicolor IFO 30338, 10 kinds of fluorescence compounds were isolated. Sterigmatocystin was produced $38{\mu}g/kg$ in 16%, $329{\mu}g/kg$ in 25% and $380{\mu}g/kg$ in 35% moistured rice 20 days culture respectively. Aflatoxin $B_1$ was produced $3{\mu}g/kg$ in 25% and $12.6{\mu}g/kg$ in 35% moistured rice 20 days culture. In embryo test of isolated fraction 2, 4 and 6 by T.L.C., $LD_{50}$ of fraction 2 was $40{\mu}g/egg$ and fraction 4,6 was $60{\mu}g/egg$, and these compounds were mostly decomposed and fraction 4 and 6 were partly changed into fraction 2 below pH 2 and above pH 10. fraction 2,4 and 6 were all stable when treated 60 min, at $100^{\circ}C$, but were decomposed $60{\sim}65%$ when treated 60 min at $150^{\circ}C$, $95{\sim}100%$ when treated 10 min at $200^{\circ}C$.