Caffeine Inhibition of Sterigmatocystin, Citrinin, and Patulin Production (original) (raw)
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Letters in applied microbiology, 2016
The objective of this study was to evaluate the effect of different caffeine concentrations (0-4%) on (i) lag phase prior to growth, (ii) growth rates and (iii) ochratoxin A (OTA) production by strains from the Aspergillus section Circumdati and Aspergillus section Nigri groups, isolated from coffee, when grown on a conducive medium at 0·98 water activity and 30°C. The lag phases prior to growth increased with caffeine concentration. A strain of Aspergillus niger and Aspergillus carbonarius were the most sensitive to caffeine with growth being inhibited by <1% caffeine. For strains of Aspergillus westerdijkiae, Aspergillus ochraceus and Aspergillus steynii, although growth was inhibited significantly, some growth (10-15% of controls) occurred in 4% caffeine. OTA production was significantly inhibited by only 0·5% caffeine for strains of A. westerdijkiae, A. niger and A. carbonarius. For A. steynii at least 1·5% caffeine was required to inhibit OTA production. In contrast, for the...
Caffeine Inhibition of Ochratoxin A Production
Journal of Food Science, 1982
The effect of caffeine and theobromine on growth and ochratoxin A production by AspergiZZus ochraceus was determined using microbiological medium. Caffeine produced a small decrease in growth, while reducing ochratoxin production as much as 98%. Theobromine had relatively little effect on growth or ochratoxin production. Screening of caffeine for its effect on the growth of a number of Aspergillus and Penicillium species indicated that caffeine may have biological activity against a variety of mycotoxigemc molds.
Further Characterization of a Caffeine-Resistant Mutant of Aspergillus parasiticus
Journal of Food Science, 1988
Studies were performed to characterize further Aspergillusparasiticus BCRl, a caffeine-resistant mutant ofA. parasiticus NRRL 2999, particularly in regard to its caffeine-dependent production of aflatoxins. The enhanced synthesis of aflatoxins by caffeine was highly specific since neither dimethylxanthines nor purines could substitute for the trimethylxanthine. Caffeine's effects were phase dependent and only increased toxin formation if added early in the microorganism's life cycle. The ability of BCRl to exclude caffeine appeared dependent on the initial levels of caffeine in the growth medium. Respiration and glucose utilization in the wild type strain were inhibited strongly by caffeine, but BCRl was resistant to these effects. Comparison of glucose uptake kinetics in the wild type and mutant strains indicated that caffeine inhibition of aflatoxin synthesis in the wild type was not due to a disruption of glucose transport.
Journal of Food Science, 1987
Aspergillus parasiticus BCRI, a caffeine-resistant mutant of A. parasiticus NRRL 2999, produced abundant amounts of aflatoxins (AF) in yeast extract-sucrose broth only when the medium was supplemented with caffeine. However, little AF production occurred in glucose-mineral salts medium (GMS) regardless of the level of caffeine supplementation. Caffeine-dependent AF production was restored if GMS were fortified with peptone or some other source of amino acids. Subsequent studies indicated that this effect could be achieved by supplementing GMS with specific amino acids, particularly proline, alanine, methionine, arginine or asparagine. Restoration of caffeine-dependent AF synthesis did not occur when GMS was supplemented with purine bases or nucleotides. The results indicated that caffeine-dependent AF production in BCRI was dependent on amino acid catabolism.
Caffeine inhibition of aflatoxin production: mode of action
Applied and Environmental Microbiology, 1983
Evaluation of caffeine and a number of related methylxanthines indicated that the ability of the compound to inhibit growth and aflatoxin production by Aspergillus parasiticus is highly specific and does not involve an inhibition of cyclic AMP phosphodiesterase. Supplementation of the culture medium with purine bases, nucleosides, and nucleotides suggested that the inhibition of fungal growth could be partially overcome by adenine or guanine but that the purines had little effect on the inhibition of aflatoxin production. Likewise, increasing the levels of trace minerals did not overcome the inhibition of toxin production. Electron microscopic evaluation of caffeine-treated and-untreated cultures indicated that the compound produced observable changes in the ultrastructure of the fungus.
Caffeine inhibition of aflatoxin synthesis: probable site of action
Applied and Environmental Microbiology, 1984
Aflatoxin production by pregrown cultures of Aspergillus parasiticus was completely inhibited by incorporation of 2 mg of caffeine per ml into the medium. This was accompanied by a decrease in glucose utilization and an inhibition of oxygen uptake and carbon dioxide evolution. Enzyme analyses indicated no significant differences in specific activities on glucose-6-phosphate dehydrogenase, mannitol dehydrogenase, phosphofructokinase, fructose-1,6-diphosphatase, pyruvate kinase, or malate dehydrogenase. Glucose uptake kinetics indicated a linear dose-related inhibition of glucose uptake. It appears likely that caffeine inhibits aflatoxin synthesis by restricting the uptake of carbohydrates which are ultimately used by the mold to synthesize this family of mycotoxins.
A New HPLC Analytical Method to Study Fungal Caffeine Metabolism
Biotechnology Techniques, 1998
A simple and rapid HPLC method has been developed to analyse all the methylxanthines that can be produced by N-demethylation of 1,3,7-trimethylxanthine (caffeine). This method is particularly suitable to study caffeine metabolism of a filamentous fungus (Aspergillus sp V12A25) cultivated in a synthetic liquid medium containing caffeine as the sole source of nitrogen.
Caffeine: also a fungal metabolite
Phytochemistry, 2000
Caeine has been found to occur as a fungal metabolite and to be the principal alkaloid in sclerotia of Claviceps sorghicola, a Japanese ergot pathogen of Sorghum spp. 7