الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
One hundred and fourteen Streptomycetes and fungal strains were isolated from both marine and terrestrial Egyptian habitats and screened for their ability to produce bioactive secondary metabolites with antidermatophytic activity by well-diffusion methods. Extracts from isolates A1, A3, A10, G5 and P4 exhibited potent antidermatophytic activity against Trichophyton mentagrophytes (RCMB 09285), Microsporum canis (RCMB 07321) and Microsporum gypseum (RCMB 07336). These potent isolates were identified by studying their morphological, physiological and biochemical characteristics and microscopical studies. The most potent isolate (P4) was genetically identified by emplifying 16S rRNA gene using PCR technique. According to information from the gene bank it was identified as a new strain and coded as Streptomyces sp. MER4. Streptomyces sp. MER4 was scaled up and the extract was fractionated by Sephadex LH-20 column with a gradient mobile phase DCM: Methanol and by liquid-liquid partition using (H2O: n-hexane: ethanol: n-butanol) to yield four fractions (P4-H20, P4-Hex, P4-but and P4-eth). Each single fraction was assessed by determination of antidermatophytic activity using agar-well diffusion method. The fraction that showed high inhibition ratio against all tested dermatophytes was (P4-eth). (P4-eth) was further subjected to many instruments to elucidate its structure.