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Document Type |
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Thesis |
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Document Title |
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GENOMIC INSIGHT INTO THE DIVERSITY OF MARINE BACTERIA ASSOCIATED WITH MARINE INVERTEBRATES IN THE RED SEA AND THEIR ANTIFOULING POTENTIALS النظرة الجينية لتنوعات البكتيريا البحرية المختلفة والمرتبطة بالالفقاريات البحرية في البحر األحمر وتأثيراتها المضادة للحشف البحري. |
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Subject |
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Faculty of Marine Sciences |
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Document Language |
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Arabic |
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Abstract |
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Marine biofouling which is the accumulation of living organisms on submerged substrates is a major problem for maritime and marine technology sectors. It has economic and environmental consequences which suggest the need for its prevention and control to minimize or eliminate its impact. One of the most important and effective control strategy in practice is the application of chemical biocide in paintings (as coatings) to prevent the attachment of fouling organisms. Due to the detrimental effects of the biocides, several nontoxic and environmentally friendly alternatives are being explored to serve as replacement. In the marine environment, a great diversity of microorganisms exists in association with marine invertebrates where they provide protection in form of chemical defense to their host making them suitable for the study and exploration of new antifouling agents. In this study, natural compounds in the form of secondary metabolites from marine bacteria associated with invertebrates were explored as potential sources of new antifouling compounds. Sponges and soft corals were collected from the Red Sea for the isolation of marine bacteria associated with them. The bacteria were identified with 16S rRNA method as well as morphological and biochemical characteristics. Intracellular and extracellular extracts were obtained from the bacteria associated with two soft coral species identified as Sarcophyton glaucum and Heteroxenia fuscenses and subjected to antifouling screening. Intracellular extracts were obtained from the sponge Siphonochalina siphonella symbionts and the effect of nutritional conditions on the antifouling activity and metabolites produced were analysed. The extracts were evaluated for antibacterial and antibiofilm activity against biofilm forming bacteria isolated from the Red Sea. They were also evaluated for antisettlement and antilarval activity against the larvae of barnacles. Each of the extracts was further evaluated for the detection of metabolites by Gas chromatography-mass spectrometry (GC-MS). Several bacteria were isolated and identified including members of the genera: Bacillus, Oceanobacillus, and Enterobacter. The extracts showed antibacterial activity against biofilm bacteria ranging from low to high activity and significant activity against biofilm formation across all the tested strains. Antilarval settlement range from 0 to 100% with little to no toxicity. A change was observed in the activity and the metabolites presence in the extracts when different nutrients were used for the extraction. Compounds detected in the extracts include known antimicrobial metabolites such as Pyrrolo[1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl)-; Pentane, 2,4-dimethyl-2-nitro-, 2,4-bis(1,1-dimethylethyl)-phenol and Undecane. Overall, bioactive compounds produced by the symbiotic bacteria associated with marine invertebrates could serve as novel source of antifouling compounds to prevent biofouling formation.
Key words: Biofouling, antifouling, symbiotic bacteria, invertebrates, natural products |
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Supervisor |
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Dr. Mamdoh Taha Jamal |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1445 AH
2023 AD |
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Co-Supervisor |
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Dr Satheesh Sathianeson |
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Added Date |
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Monday, September 18, 2023 |
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Researchers
| إدريس عبد الرحمن | Abdulrahman, Idris | | Researcher | Doctorate | |
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