• Journal of Food Hygiene and Safety
• /
• v.4 no.3
• /
• pp.165-170
• /
• 1989

To isolate the aflatoxin producing strains from agricultural products in Youngnam districts, rice(59), meju(30), corn(32), barley(58), soil(33), peanut(30), soybean(45), and unhulled barley(60) were collected from markets or homes. From 342 sample sources, 280 strains of Aspergillus spp. were isolated. As a result of screening by TLC, 29 strains expressed fluorescent spot and four strains have a same Rf value of standard aflatoxins, and the percentage of contamination from aflatoxin producing strains was 1.3%, and those strains were estimated as Aspergillus flavus group by the examine of characteristics and morphology.

• The Korean Journal of Mycology
• /
• v.13 no.4
• /
• pp.243-247
• /
• 1985

Experiments were conducted to study effects of steroidal carbamate derivatives upon mycelial growth and aflatoxin production by Aspergillus flavus ATCC 15517. The basal medium was supplemented with various concentrations of these compounds and inoculated with spores. The developing cultures were incubated for 11 days at $28^{\circ}C$ without agitation. Aflatoxins were extracted with chloroform, separated by thin layer chromatography, and quantitated by ultraviolet spectrophotometry. At a concentration of 50 mg per 30 ml of medium., stigmasteryl-N-(2-chloroethyl) carbamate, cholesteryl- N - (2-chloroethyl) carbamate, $5{\alpha}-cholestan-3-one-oximino-N-(2-chloroethyl)$ carbamate and ${\beta}-sitosteryl-N-(2-chloroethyl)$ carbamate were the most effective in reducing aflatoxin production by Aspergillus flavus. However, cholest-4-ene-3-one-oximino-N-(2-chloroethyl) carbamate, at a concentration of 100 mg per 30 ml, significantly decreased aflatoxin production. There was no significant inhibition of mycelial growth by the addition of the various concentrations of these compounds.

• Mycobiology
• /
• v.38 no.4
• /
• pp.229-237
• /
• 2010

Members of the genus Aspergillus are the most common fungi and all reproduce asexually by forming long chains of conidiospores (or conidia). The impact of various Aspergillus species on humans ranges from beneficial to harmful. For example, several species including Aspergillus oryzae and Aspergillus niger are used in industry for enzyme production and food processing. In contrast, Aspergillus flavus produce the most potent naturally present carcinogen aflatoxins, which contaminate various plant- and animal-based foods. Importantly, the opportunistic human pathogen Aspergillus fumigatus has become the most prevalent airborne fungal pathogen in developed countries, causing invasive aspergillosis in immunocompromised patients with a high mortality rate. A. fumigatus produces a massive number of small hydrophobic conidia as the primarymeans of dispersal, survival, genome-protection, and infecting hosts. Large-scale genome-wide expression studies can now be conducted due to completion of A. fumigatus genome sequencing. However, genomics becomes more powerful and informative when combined with genetics. We have been investigating the mechanisms underlying the regulation of asexual development (conidiation) and gliotoxin biosynthesis in A. fumigatus, primarily focusing on a characterization of key developmental regulators identified in the model fungus Aspergillus nidulans. In this review, I will summarize our current understanding of how conidiation in two aspergilli is regulated.

• Interdisciplinary Bio Central
• /
• v.2 no.4
• /
• pp.10.1-10.5
• /
• 2010

Total aflatoxin and ochratoxin were detected in 3 naturally contaminated fish feed samples using immune-affinity method. The results revealed that the average levels of aflatoxins in the 3 examined samples were (15, 22 and $12\;{\mu}g/kg$) respectively while the average levels of ochratoxins were (15, 6 and $6\;{\mu}g/kg$). The results of determination of the effects of clay as a mycotoxin binder on the health status and performance of Oreochromis niloticus in comparing with a control group revealed that the survival rate in control group was 81% after the end of the culture season. The results also revealed that the survival rate in group 2 which received clay treated feed was 86%. The results of regular parasitological examination revealed the identification of trichodina as external protozoa in Oreochromis niloticus from both ponds but without manifestation of disease signs. The results of bacteriological examination revealed the isolation and identification of Pseudomonas flouresence from some moribund Oreochromis niloticus. Higher performance parameters were recorded in group 2 that received feeds treated with clay which reflected in the total production which reaches 1646.47 kg while in the control pond, the total production was1308.36 kg.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.5
• /
• pp.767-774
• /
• 1997

For the standardization and quality improvement of traditional Korean Nuruk, 120 strains of fungi were isolated from Nuruks and 18 strains of them were selected as strains analysing the amylase and flavor. The genera of these fungi were identified as Aspergillus sp. (14 strains), Penicillium sp. (3 strains) and Rhizopus sp. (1 strains) by the conventional slide culture. Most of these fungi showed a better productivity of the saccharogenic and dextrinogenic enzymes in raw wheat bran culture than in cooked wheat bran culture. The ability of acid and flavor production was good in the raw wheat bran culture, and aflatoxins were not produced under the same culture. Penicillium sp. and Rhizopus sp. had high cell growth and amylast activity. Mixed culture of Aspergillus sp. No.3-6 and Penicillium sp. No.7-7 revealed a high liquefying and saccharifying activity as well as high flavors production. These results indicated that these fungi was proper strains for making Nuruk of good quality.

• Mycobiology
• /
• v.33 no.2
• /
• pp.77-83
• /
• 2005

Seventy-three fungal species belonging to forty-three genera were isolated from 40 samples of Saccharrum officinarum (collected from Naage-Hamadi canal in Qena Governorate, Egypt). Aspergillus, Trichoderma, Mucor and Pythium were the most common genera on the two isolation media. The dominant species of Aspergillus were A. niger, A. flavus, A. ustus, A. terreus and A. wentii. Some species were dominant on 40 g/l sucrose such as Aspergillus niger, A. flavus, Emericella nidulans, Trichoderma viride, Torula herbarum and Mamaria echinoeotryoides, while the dominant species on 10 g/l glucose were Mucor circinelloides, Aspergillus niger, Torula herbarum and Trichoderma viride. Mycotoxins including aflatoxins $B_1,\;B_2,\;G_1\;and\;G_2$, zearalenone and diacetoxyscirpenol were detected in the examined samples of Saccharrum officinarum. The mycelial growth of A. flavus, A. niger, Fusarium moniliforme and Torula herbarum decreased with the increase in Dimethoate concentrations, although 25 ppm was less effective than the higher levels of the insecticide ($75{\sim}200\;ppm$). Dimethoate stimulated the activity of Go-Tin A. niger, F. moniliforme and T. harbarum, while the Go-T activity was inhibited in A. flavus with the Dimethoate treatments.

• Korean Journal of Food Science and Technology
• /
• v.1 no.1
• /
• pp.45-50
• /
• 1969

On the basis of UV spectral changes and TBA reaction, malonaldehyde (MA) in aqueous solution receives considerable photochemical modification by UV light of short wavelengths around $260m{\mu}$. When aflatoxin is added in the solution, UV light of long wavelengths around $360m{\mu}$ induces such changes quite rapidly and although the rate of change is rather slow, it is also true even with ordinary laboratory illumination(fluorescent). The modification is irreversible in nature and the role of aflatoxin in this reaction is identified as a photosensitizer. The mechanism involved in this modification is apparently due to the parallel dimerization of MA molecules, but not by head to tail combination of the molecules.

• Korean Journal of Food Science and Technology
• /
• v.1 no.1
• /
• pp.78-84
• /
• 1969

An attempt has been made to investigate the possible occurrence of aflatoxins, a group of micotoxin which are toxic metabolites produced by Aspergillus flavus, and aflatoxin like substances in fungal fermented soybean products such as meju and soybean paste. Chloroform extracts from 15 samples which has been defated with petroleum ether are subjected to separations with thin-layer chromatography on silica gel washed with methanol prior to film coating, improves the chromatographic separation and ultraviolet absorption spectral identification. In addition to fluorescencing spot having an Rf value which is same as aflatoxin $B_1$, many of the fluorescencing spots have been occurred in every sample examined. Each fluorescencing spot is scratched and the ethanol extracts are subjected to further separation with thin-layer chromatography. Each fluorescence substance is eluted with ultra violet transparent absolute ethanol and the ultraviolet absorption spectra are checked. None of the absorption curve of eluates shsow accordance with the curve of aflatoxin. 2, 4-Dinitrophenyl hydrazine reagent, Tollen's reagent and ninhydrin reagent are applied on the chromatogram- The data show that aflatoxin is not present in any of the fungal preparations examined.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2001.10b
• /
• pp.3-4
• /
• 2001

Residents of Qidong, Peoples Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of foods contaminated with aflatoxins. Chlorophyllin, a mixture of semi-synthetic, water-soluble derivatives of chlorophyll that is used as a food colorant and over-the-counter medicine, has been shown to be an effective inhibitor of aflatoxin hepatocarcinogenesis in animal models.(omitted)

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2001.10a
• /
• pp.46-47
• /
• 2001

Residents of Qidong, Peoples Republic of China, are at high risk for development of hepatocellular carcinoma, in part due to consumption of foods contaminated with aflatoxins. Chlorophyllin, a mixture of semi-synthetic, water-soluble derivatives of chlorophyll that is used as a food colorant and over-the-counter medicine, has been shown to be an effective inhibitor of aflatoxin hepatocarcinogenesis in animal models.(omitted)