Fungal populations and mycotoxins in silage in Assiut and Sohag governorates in Egypt, with a special reference to characteristic Aspergilli toxins.

Forty silage samples were collected from Assiut and Sohag governorates in Egypt to measure the presence of fungal population in silage. Forty-three species and 2 species varieties belonging to 17 genera were isolated using glucose Czapek's and Sabouraud's dextrose agar media at 28 degrees C. The most prevalent genera were Aspergillus (57.5 and 100 of the samples), Penicillium (100 and 55%) on the two mentioned media, respectively. Also, Fusarium oxysporum and Gibberella fujikurori were recovered in moderate incidences. Mycotoxin profiles were also determined in these samples: Aflatoxins showed the highest incidence rates of occurrence, it occurred in 22.5% of all samples analyzed. Other mycotoxins were detected from all samples (T2 toxins and sterigmatocystin at incidence of 7.5 and 5%, respectively). The screening of the characteristics mycotoxins of different isolates of Aspergillus isolated from silage samples was tested. The results clarified that some mycotoxins (aflatoxins-aspergillic acid-beta nitro propionic acid-cyclopiazonic acid-kojic acid and sterigmatocystin) were produced by some isolates of A. flavus. Some isolates of A.fumigatus could produce gliotoxin and verrucologen. All of A. niger isolates tested were able to produce kojic acid. One isolate of A. ochraceous formed ochratoxin A and other isolate produced penicillic acid. Concerning A. terreus isolates, the results showed that 5 isolates were able to produce citrinin and 4 isolates had ability to produce patulin. A. versicolor isolates showed the ability to produce ochratoxin A.

Hydroxylation of progesterone by some Trichoderma species.

Thirty-three isolates belonging to six species of the genus Trichoderma were tested for the ability to hydroxylate progesterone to 11alpha-, 11beta-, 11alpha,17alpha- and 6beta, 17alpha-derivatives, and epicortisol. T. aureoviride, T. harzianum, T. polysporum and T. pseudokoningii produced 11alpha-hydroxyprogesterone. T. harzianum and T. hamatum can form only the 11beta-isomer. T. koningii and T. hamatum produced 11alpha-, 11beta-, 11alpha,17alpha- and 6beta,11alpha-hydroxy derivatives. 11alpha, 11beta, 6beta,11alpha- and 11alpha,17alpha-hydroxyprogesterones and epicortisol are produced by T. aureoviride and T. pseudokoningii. Cortisol was produced only when the medium was fortified by 10 g/L peptone. This is the first record of conversion of progesterone to mono-, di- and trihydroxyprogesterones by these Trichoderma species.