الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
6. Summary
Secondary metabolites are compounds neither essential for growth nor key intermediates of the organism’s basic metabolism however playing other roles within the life of microorganisms. They’re typically found as a mix of closely connected molecules with a peculiar and rare chemical structure. Secondary metabolites extracted from living microorganisms such as antibiotics, pigments, toxins, effectors of ecological competition and symbiosis, pheromones, enzyme inhibitors, pesticides, antitumor agents and growth promoters of animals and plants, and can play great role in medicine.
The current study has been performed on twelve bacterial isolates, which were collected from Benha University Hospital’s Microbiology and Immunology Department. The isolates identified using VITEK-2 cards system to confirm the conventional biochemical identification of the twelve bacterial isolates. So, by morphological, cultural, biochemical characteristics and VITEK2 system isolates (B12) were confirmed as Pseudomonas aeruginosa.
Marine microorganisms are a source of new genes, and it is probably going to prompt the revelation of new medications and targets. Secondary metabolites produced by marine microbes have yielded pharmaceutical items. So, sixteen isolates (H1- H16) were isolated from Hurghada at the Red Sea. Pre-screening of biological antibacterial activity for the ethyl acetate crude extracts of these isolates against twelve different Multi-Drug-Resistance Bacteria (B1 – B12) was done by using a plate assay method. The acetate extracts which isolated from actinomycetes were tested for their antimicrobial activity. Several isolates exhibited antimicrobial activity against different bacterial isolates but one isolate (H2) from the 16 actinomycetes isolates showed potent antimicrobialn activity and were the most effective. While the most of crude extract have a variable activity against bacterial isolate.
The actinomycetes isolate (H2) has high antibacterial activity against Pseudomonas aeruginosa subjected to molecular identification. The identification was achieved by Morphological, physiological, biochemical and chemo-taxonomical characteristics of Streptomycetes isolate H2 and Molecular identification. The sequence data obtained from the Streptomycetes has been submitted to GeneBank. It has been confirmed that the strain is a member of the genus Streptomyces spp. We have assigned its name as Streptomyces parvulus strain MDA. The strain has been recorded in the GenBank database with accession no.OQ179632.1).
The strain Streptomyces parvulus strain MDA was cultivated on rice medium. After harvesting and scaling up, the obtained crude extract was purified utilizing a variety of chromatography techniques then pure nine metabolites were delivered which showed antibacterial activity against twelve Bacterial isolates. Then, a fraction that purified using a series of chromatographic techniques to obtain a pure compound with the highest activity against the twelve bacterial isolates was selected. The structure of the pure compounds with the high activity were verified using several spectroscopic methods (NMR and MS).
Based on the above spectral data, bioactive compound was identified as 2-Methyl butyl propyl phthalate. With the molecular formula of C16H22O4.
In our study, an interesting finding is the inhibition of the Pseudomonas aeruginosa (B12) by 2-Methyl butyl propyl phthalate. The results showed significant inhibition with promising antibacterial parameters, Based on the preliminary antibacterial results, the MIC and MBC which were measured toward Pseudomonas aeruginosa (B12) and the experiments were carried out three times to confirm the MIC and MBC data. The MIC assay for the extracts was found to be about 80 µg/ml. while the MBC was 300 µg/ml. The results revealed that the extract exhibited bactericidal activity against the tested strains. Pseudomonas aeruginosa (B12) was killed by 2-Methyl butyl propyl phthalate within 5 hours.