الفهرس 
MyceliaOnly 14 pages are availabe for public view
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Abstract
Discovery of new important natural products takes place when new screening programs were carried out or when samples from new sources were examined. In our program, samples were collected from different localities of Egypt such as Tanta, Cairo, Alexanderia, Kafre El Shiech, Mansoura, Shebien El-Koom, Assuit, Fayom, Minia and Aswan, which were collectively 53 sampling sites . All samples were pretreated with heating, that allowed selective isolation of actinomycetes, which are normally rare or present in a few cells per gram. On the other hand, addition of antibacterial antibiotics reduced the total number of actinomycetes, but allowed more resistance strains to develop. Furthermore, addition of nystatin to the isolation media enhanced actinomycetes isolation. About 50 different strains of actinomycetes were isolated, of which only 19 isolates were exhabited antagonistic activities against Candida albicam or /and Eschel-ichia coli. Examination of different cultures revealed that about 35 strains were belonging to the genus Streptonzyces . Six diferent isolates were selected and recoginized for their high ablity to prevent the growth and development of C. albicarzs. In the current work, they were gaven name AFS 1, AFN2, AFF3, AFD16, AFW20 and AFS60 Strains WS1, AFN2 and AFF3 were found to be the most potent inhibitor of the growth of C. albicans in vitro. They produced non polyenic antifungal agents as revealed by the the UV spectra. Cultivation of C. albicans on Sabouraud agar enriched with ergosterol, the experimental organisms AFD16, AFW20, AFS60 lost their antagonistic activity against C. ctlbictrrzs, confirmed the non polysnic structure. Thus , strains AFS1, AFN2, and AFF3 were selected for further studies. Extraction was carried using different organic solvents, 11- butanol and ethyl acetate were se.lected for effective extraction at the acidic pH value. The selected actinomycetes AFS1, AFN2 and AFF3 were cultivated in 2 L fermentor for 7 days at 28 ”C. The active materials were extracted. Purification was achieved using gel filtrations. Biogel and silica gel column chromatography.