Antimicrobial activity of aflatoxins.

Journal of Bacteriology (Impact Factor: 2.81). 02/1967; 93(1):59-64.
Source: PubMed


Antimicrobial activity of a crude aflatoxin preparation and of aflatoxin B(1) was studied. They were found inactive against common gram-positive and gram-negative bacteria at a concentration of 100 mug/ml. Both samples of aflatoxin did, however, exhibit antimicrobial activity, though narrow and limited, against various strains of Streptomyces and Nocardia. The antibiotic action of aflatoxin B(1) was confirmed by bioautogram after thin-layer chromatography. Among seven strains of microorganisms, including aflatoxin-sensitive and -resistant strains, N. asteroides IFM 8 was found to reduce aflatoxin B(1), in addition to other minor fluorescent components in the crude preparation.

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    • "Other microorganisms were also tested for their possible ability to degradate aflatoxins. The strain Nocardia asteroides reduces AFB 1 by biotransformation to another fluorescent product (Arai et al., 1967), and Corynebacterium rubrum is able to detoxify aflatoxin as well (Shapira, 2004). "
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    ABSTRACT: Aflatoxins are cancerogenic compounds produced predominantly by certain strains of the Aspergillus genus. The ideal solution for minimization of health risk that aflatoxins pose is the prevention of foods and feeds contamination. Unfortunately, these contaminants can never be completely removed, and on that account, many studies have been carried out to explore an effective process of their detoxification to a threshold level. Biological decontamination seems to be attractive because it works under mild, environmentally friendly conditions. This review is focused on the biological detoxification of aflatoxins, especially aflatoxin B1, by microorganisms. There are briefly mentioned aflatoxin metabolic pathways in the human and animal body. Microorganisms such as soil or water bacteria, fungi, and protozoa and specific enzymes isolated from microbial systems can degrade aflatoxin group members with varied efficiency to less- or nontoxic products. Some aflatoxin-producing fungi from Aspergillus species have the capability to degrade their own synthesized mycotoxins. Yeasts and lactic acid bacteria work as biological adsorbents that prevent aflatoxin's transfer to the intestinal tract of humans and animals. Aflatoxin B1 absorbed into the organism could be metabolized by significantly different pathways. They lead to the production of the relatively nontoxic compounds, on the one hand, or to highly toxic active forms on the other hand.
    Drug Metabolism Reviews 02/2009; 41(1):1-7. DOI:10.1080/03602530802563850 · 5.36 Impact Factor
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    • "The toxicity of aflatoxins has led to suggestions that they have a role in competition, either as antibiotics against microorganisms or as toxic agents/feeding deterrents against arthropods. Aflatoxins show no or low toxicity against bacteria (Arai et al. 1967), and inhibition of fungal sporulation varies considerably according to species and growth medium (Reiss 1971). When added to soil, aflatoxins have minimal inhibitory effects on microbial growth, possibly due to their rapid degradation by microorganisms (Angle and Wagner 1980, 1981). "
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    ABSTRACT: Fungi belonging to Aspergillus section Flavi are of great economic importance in the United States due to their ability to produce toxic and carcinogenic aflatoxins in agricultural commodities. Development of control strategies against A. flavus and A. parasiticus, the major aflatoxin-producing species, is dependent upon a basic understanding of their diversity in agricultural ecosystems. This review summarizes our current knowledge of species and population diversity in the United States in relation to morphology, mycotoxin production and genetic characters. The high genetic diversity in populations of aflatoxigenic fungi is a reflection of their versatile habits in nature, which include saprotrophic colonization of plant debris in soil and parasitism of seeds and grain. Genetic variation within populations may originate from a cryptic sexual state. The advent of intensive monoculture agriculture not only increases population size but also may introduce positive selective pressure for aflatoxin production due to its link with pathogenicity in crops. Important goals in population research are to determine how section Flavi diversity in agricultural ecosystems is changing and to measure the direction of this evolution.
    Food Additives and Contaminants 11/2007; 24(10):1088-101. DOI:10.1080/02652030701510012 · 2.13 Impact Factor
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    ABSTRACT: Tetrahymena pyriformis W with nutrients, ca. 22 x 10 cells, decreased the concentration of aflatoxin B(1) 58% in 24 hr and 67% in 48 hr. An unknown, bright-blue fluorescent substance was produced, with intensity about one-half that of the unchanged B(1), with an R(f) of 0.52 compared with 0.59 for B(1) and 0.55 for B(2) on a thin-layer chromatography plate, and with an ultraviolet spectrum showing maxima of 253, 261, and 328 mmu. In a separate assay, the cells with nutrients did not degrade pure G(1). Starved, washed cells, ca. 11 x 10, decreased the concentration of B(1) 50% in 10 hr, 70% in 22 hr, and 75% in 30 hr, producing the same unknown component. Ethyl alcohol, 1.96% (v/v), decreased cell populations and size, but the cells remained actively motile in broth plus the alcohol for 96 hr. In 72 hr, neither toxin (ca. 2 ppm) in combination with ethyl alcohol had more inhibitory effect on cell numbers, with or without nutrients, than was produced by alcohol alone. Aflatoxin B(1) had no observed effect on the viability of the starved cells for 30 hr or on the nourished cells for 72 hr. There was no noticeable effect of G(1) on the starved cells in 30 hr or on the nourished cells in 48 hr. After 72 hr with G(1) plus nutrients, many of the cells were round with blisters, nonmotile, and apparently dead or dying.
    Applied microbiology 10/1967; 15(5):1099-103.
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