Four fungal strains, namely, AspergiUus niger, Eurotium herbariorum, a Rhizopus sp., and non-aflatoxin (AF)-producing Aspergillus flavus, which could convert AF-B1 to aflatoxicol (AFL), could also reconvert AFL to AF-B1. The interconversion of AF-B1 to AFL and of AFL to AF-B1 was ascertained to occur during proliferation of the fungi. These reactions were distinctly observed in cell-free systems obtained from disrupted mycelia of A. flavus and the Rhizopus sp., but they were not observed in culture filtrates from intact (nondisrupted) mycelia of the same strains. The interconversion activities of AF-B1 and AFL were not observed when the cell-free systems were preheated at 100°C. These findings strongly suggest that the interconversion of AF-B1 and AFL is mediated by intracellular enzymes of A. flavus and the Rhizopus sp. In addition, the isomerization of AFL-A to AFL-B observed in culture medium was also found to occur by the lowering of the culture pH. Aflatoxicol (AFL) is formed by reduction of the cyclopentenone carbonyl of aflatoxin (AF)-B, and has two types of stereoisomers, AFL-A and AFL-B, determined by the stereoconfiguration of the OH group in the cyclopentenol ring (2) (Fig. 1). AFL is well known (1) as a main in vitro metabolite produced from AF-B, by reductase in the supernatant of liver homogenates of several avian and mammalian species. It has also been reported that AFL is produced from the biological reduction of AF-B, by microorganisms such as Rhizopus spp. (3), Dactylium dendroides (4-6), Absidia repens (5), Mucor griseo-cyanus (5), Aspergillus niger (8, 9), Mucor ambiguus (8, 9), Trichoderma viride (8, 9), Streptococcus lactis (10), and Tetrahymena pyriformis (14). These facts suggest the possibility of detecting AFL in foods and feeds contaminated with AF-Bl. Saito et al., in this laboratory (16), reported the simultaneous contamination of commercial pistachio nuts and corn with AFL and AF-B, in 1984, in the first report on natural contamination of food with AFL. To elucidate the cause of natural AFL contamination, we reported the abilities of various species of non-AF-Blproducing fungi which were isolated from AFL-contaminated corn to convert AF-B, to AFL. As a result, it was found (11) that A. niger, Eurotium herbariorum, the Rhizopus sp., etc., had fairly potent conversion abilities. It was also found (12) that several strains of AF-Bl-producing Aspergillus flavus isolated from AFL-contaminated corn showed a fairly high AFL-producing ability. As mentioned above, the conversion of AF-B, to AFL by microorganisms has already been demonstrated, but little is known about the reverse conversion, namely, that from AFL to AF-Bl. This paper deals with the metabolic interconversion of AFL and AF-B, by non-AF-producing fungi isolated from AFL-contaminated corn. * Corresponding author. MATERIALS AND METHODS Organisms. The fungal strains used in this study were the following: A. niger C-41-i, E. herbariorum C-41-f, Rhizopus sp. C-40-m, and non-AF-producing A. flavus C-40-d, which were isolated from AFL-...

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A liquid chromatographic (LC) procedure is described for the determination by dansylation of the following 16 kinds of biogenic amines found In wine: monomethylamine (MM), ethylamine (EM), iso- and n-propylamlne (Pr), iso- and n-butylamine (Bu), iso- and n-amylamlne (Am), pyrrolidine (PY), 2- phenethylamine (PH), tryptamine (TR), putresclne (PU), cadaverine (CA), histamine (HI), tyramine (TY), and spermidine (SP). The amines In white and red wine were applied to a column of Amberllte CG-50 type I resin (Na-form) after the column had been washed with water and eluted with 1N hydrochloric acid. This eluate was evaporated to dryness under reduced pressure and derivatized with dansyl chloride (DNS). LC separations were performed on Finepak SIL C18S and LiChrosorb RP-8 columns with an acetonitrile-water elution gradient. In the survey of commercial wines by this method, most of the samples were found to contain 12 amines, including iso-Am, CA, PU, TY, and others. The highest levels of these amines were 4.84 μg PU/mL in red wine, and 5.11 μg Iso-Am/mL in white wine. The total levels of amines in red wine were comparatively higher than in white wine.