الفهرس 
Title : A study on the microbial diversity and antimicrobial activity associated with the marine life in Great Bitter Lakes
ContentsOnly 14 pages are availabe for public view
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Abstract
Marine microorganisms are a prospective source of new natural chemicals that have a wide range of medicinal and biotechnological applications. The geographical, physicochemical, and biological distinctiveness of Great Bitter Lake’s marine ecology makes the bacterial population there of importance for research.
The higher salinity level of the Bitter Lakes is hypothesized to be a driving force for production of active secondary metabolites.
Different approaches have been used to investigate the marine microbial communities and their metabolites including culture-dependent and culture- independent techniques. Despite the importance of the culture-dependent approach to isolate a pure culture of the active bacterial strain, there are many limitations that face the culture-dependent techniques
In this study, we modified a fast and simple approach to search for active microbial strains prior to the cultivation process, depending on the relative quantification of polyketides synthases gene clusters in the total community DNA extracted from lake water and soil samples. This demonstrated that the lake’s indigenous bacterial population had a potential biosynthetic capacity. It was also a good indicator for samples with higher biosynthetic capability. We have found that the oxic marine sediment carried the highest levels of the polyketide synthases genes in relation to the total bacterial 16S rRNA gene within the sediment, making it a good target to recover active isolates.
To evaluate the used approach, we applied a culture-dependent approach to recover and isolate microbial strains with antimicrobial activity. We tested the recovered isolates for microbial antagonism, and their extracts for the antimicrobial activity.
We found four active strains. All belonged to the genus Bacillus. We tried to predict the active metabolites and their relation to the marine environment. We used PCR to scan for the most common species-related antimicrobial metabolites coding genes. We used the LC-MS to determine the probable metabolites within the active extracts.