미량원소가 aspergillus flavus의 발육과 aflatoxin 생성에 미치는 영향에 관한 연구

• 영문명: Effects of trace elements on growth and aflatoxin prodution of aspergillus flavus
• 발행기관: 한국예방수의학회
• 저자명: 박종명(Jong Myung Park) 한수남(Su Nam Han)
• 간행물 정보: 『Korean Journal of Veterinary Public Health』Vol.12, No.1, 85~108쪽, 전체 24쪽
• 주제분류: 의약학 > 면역학
• 파일형태: PDF
• 발행일자: 1988.06.30

영문 초록

Aflatoxins inducing animal aflatoxicosis are a mixture of toxic secondary metabolites produced from certain strains of Aspergillus flavus and A. parasiticus. Aflatoxin production of fungus is highly influenced by the various factors such as moisture content, temperature and nutrients including trace minerals that are required for fungal growth. This study is aimed to follow the effects of the trace elements such as zinc, copper, manganese, iron, molybdenum and boron on the growth and aflatoxin production of A. flavus in the defined medium which devoid of each of the above elements. Fungal growth and aflatoxin production were evaluated by the determination of mycelial dry weight and quantitation by thin layer chromatography-densitometry, respectively. The results obtained were summarized as follows : 1. When manganese was depleted from the medium, the gel like colony was submerged and the mycelial dry weight was decreased to 0.7437g in contrast with 3.2690g in non depleted medium(p＜0.01). 2. Zine depletion resulted in a poor aflatoxin production in cultured medium. When zinc was depleted, the aflatoxin concentration of cultured medium was 0.15 ppm, in contrast with 31.29 ppm in non depleted medium(p＜0.01). A similar tendency was observed in the case of con culture. 3. Copper was responsible to form green pigment in A. flavus colony but the color was yellow when it was depleted from the medium. The least total aflatoxin content, distributed in the cultured medium and mycelium, was observed in case of copper deficiency. 4. The distribution of aflatoxin in the medium and mycelium cultured with all the six elements were 19.89 and 89.94 ppm, respectively. However in the case of zinc depletion the mycelium contained 23.39ppm of aflatoxin but no toxin in cultured medium. This suggested that aflatoxin, biosynthesized in the mycelium, may be excreted into the medium under the favor of zinc. 5. Aflatoxins, produced in glucose-mineral medium where Mn was supplemented and heated at 121℃ for 15 minutes, appeared in two spots of B₂ and G₂. While in the medium with same condition but Mn depleted appeared four spots of B₁, B₂, G₁and G₂. The result suggest that manganese depletion may cause a poor activity of superoxide dismutase and a toxic superoxide inhibit the conversion of aflatoxin B₁and G₁into B₂and G₂, as well as the mycelial growth. 6. The trace elements such as Zn, Mn, Cu, Fe, B, Mo supplemented to glucose-mineral medium were able to produce aflatoxin B₁ in 5 days of cultivation, and the peak value(6596 ppb) was observed in 12days and then decreased thereafter. The aflatoxin B₂, however, increased until 23rd day of the cultivation at the level of 3279ppb. The production and degradation curve of total aflatoxin was similar to that of aflatoxin B₁, and decerased to half on the day of 28th. 7. Aflatoxin production was inhibited by the addition of dichlorvos(20 ppm) to the medium. This may suggest that the inhibition by dichlorvos was attributed to the inhibition of activity of aflatoxin synthetase enzyme. Therefore, dichlorvos may be applicable to prevent the aflatoxin production by A. flavus contaminated in feeds.

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키워드

Aflatoxin Aspergillus Trace elements Dichlorvos