Cornmeal agar (CMA) is a good to model natural conditions (low C and N, high antioxidants, crude fat) for phytopathogenic fungi. Different CMA media was prepared to model the maize kernel as growth environment for Aspergillus flavus, where stress resistance and aflatoxin B1 (AFB1) production were tested. The CMA medium with high polyphenol and low fatty acid content did not support the mycelial growth and high AFB1 production but the sclerotia development of the cultures. High fatty acid content in the CMA exceeded the inhibitory effect of antioxidant polyphenols of corn and low concentration of AFB1 was detected. Glucose supplement of CMA induced AFB1 production proving the need for free carbon source for the secondary metabolite pathway. The tolerance of the fungus against salt and cell membrane stress was lowered on CMA. At higher fatty acid concentration, the aflatoxin B1 production cannot be hindered by the natural antioxidants and that is important in selection of resistant corn hybrids.
Authors:M. Abdel Samei, M. Elshafie, M. Hanna, J. Csikai and M. Juhász
The protein content of various corn-meals /rice, lupine, sorghum, pumpkin, linseed, water melon, tomato/ collected from Egypt and the USA have been determined by 14 MeV neutron activation analysis via14N/n, 2n/13N reaction. Non-conventional sources like tea and coffee residues were also investigated. The concentrations of trace elements determined by the X-ray fluorescence technique show definite differences even for a given type of seed produced in different geographical regions.