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Twenty-five samples of maize kernels collected at harvest time from geographically different corn fields in Peru, were examined for the occurrence of toxigenic Fusarium species. The most frequently recovered species were F. subglutinans (48%), F. moniliforme (46%), and F. equiseti (5%). Other Fusarium species isolated (up to 1%) included F. graminearum, F. acuminatum, F. solani, F. oxysporum, and F. culmorum. Assays of Fusarium culture extracts using Artemia salina larvae, showed F. subglutinans as one of the most toxigenic species, and its toxicity was mostly correlated to the capability to produce beauvericin (BEA). All eight tested isolates of F. subglutinans grown on autoclaved corn kernels produced BEA (from 50 to 250 mg/kg) as well as moniliformin (M) (from 70 to 270 mg/Kg). This is the first report on BEA and M production by maize isolates of F. subglutinans from South America.

Fusarium graminearum Schwabe, the imperfect stage of Gibberella zeae (Schw.) Petch, is a toxigenic fungus often associated with feed refusal and emesis in animals fed with infected grains (3, 16, 17). Detailed studies on natural outbreaks ofF. graminearum toxicosis led to the identification of various mycotoxins, including zearalenones and trichothecenes (9). Based on the production of the different trichothecenes, Ichinoe et al. (5) reported the occurrence of two chemotypes of isolates of G. zeae from rice in Japan. The 'NIV-type' produces nivalenol (NIV) and fusarenone-X (FUS) while the 'DON-type' produces deoxynivalenol (DON) and 3-acetyldeoxynivalenol (3-ADON). A chemotype is defined by Pitt and Hawksworth (13) as a chemically characterized strain of morphologically indistinguishable fungi. It appears that there are geographical differences in the natural distribution of the toxigenic isolates as well as of their corresponding trichothecenes. Deoxynivalenol is found worldwide in cereals infected by Fusarium graminearum, often together with its monoacetates 15-ADON or 3-ADON (8, 10, 19). The occurrence of NIV has been reported in Japan, Korea, France, Austria and the U.K. (1, 6, 7, 15, 20), and FUS together with NIV only in Japan and in Austria (1, 20). This paper reports some preliminary data on the occurrence of both chemotypes of G. zeae on cereals in southern Italy.

The structure of paracelsin E, a new peptaibol from Trichoderma saturnisporum, has been determined primarily by fabms. The well-known paracelsins A, B, C, and D were also found in a culture of this organism.

Fourteen samples of preharvest infected corn ears, collected in 1990-1991 from different Polish cornfields, were found to be highly infected by fusarium subglutinans. This species was recently shown to produce in culture beauvericin (BEA), a toxin mostly known for its insecticidal properties. Chemical analysis by high-performance liquid chromatography and high-performance thin-layer chromatography revealed the occurrence in the naturally infected corn samples of BEA (up to 60 mg/kg). When cultured on autoclaved corn kernels for 4 weeks at 25 degrees C 8 of the 10 assayed strains of F. subglutinans produced BEA (up to 200 mg/kg), whereas 9 strains also produced moniliformin (up to 500 mg/kg). Cultural extracts containing the highest amounts of BEA proved to be toxic in Artemia salina bioassay. The natural occurrence of BEA in corn is reported here for the first time.

Aflatoxin B1 (AFB1) is the most harmful mycotoxin that occurs as natural contaminant of agricultural commodities, particularly maize. Practical solutions for detoxification of contaminated staples and reduction of agricultural wastes are scarce. We investigated the capability of the white-rot and edible fungus Plerotus eryngii (king oyster mushroom) to degrade AFB1 both in vitro and in a laboratory-scale mushroom cultivation, using a substrate similar to that routinely used in mushroom farms. In malt extract broth, degradation of AFB1 (500 ng/mL) by nine isolates of P. eryngii ranged from 81 to 99% after 10 days growth, and reached 100% for all isolates after 30 days. The growth of P. eryngii on solid medium (malt extract-agar, MEA) was significantly reduced at concentrations of AFB1 500 ng/mL or higher. However, the addition of 5% wheat straw to the culture medium increased the tolerance of P. eryngii to AFB1 and no inhibition was observed at a AFB1 content of 500 ng/mL; degradation of AFB1 in MEA supplemented with 5% wheat straw and 2.5% (w/v) maize flour was 71–94% after 30 days of growth. Further, AFB1 degradation by P. eryngii strain ITEM 13681 was tested in a laboratory-scale mushroom cultivation. The mushroom growth medium contained 25% (w/w) of maize spiked with AFB1 to the final content of 128 μg/kg. Pleurotus eryngii degraded up to 86% of the AFB1 in 28 days, with no significant reduction of either biological efficiency or mushroom yield. Neither the biomass produced on the mushroom substrate nor the mature basidiocarps contained detectable levels of AFB1 or its metabolite aflatoxicol, thus ruling out the translocation of these toxins through the fungal thallus. These findings make a contribution towards the development of a novel technology for remediation of AFB1- contaminated corn through the exploitation of the degradative capability of P. eryngii and its bioconversion into high nutritional value material intended for feed production.