Summary of Organic Chemistry doctoral thesis: Study on antimicrobial secondary metabolites isolated from selected marine-derived actinobacteria strains belong to Streptomyces genus

Isolation and screening for Vietnam antimicrobial marine-derived actinobacteria strains; isolation and structure elucidation of compounds from 2 promising isolated actinobacteria strains; determination the antimicrobial activities of isolated compounds.
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Summary of Organic Chemistry doctoral thesis: Study on antimicrobial secondary metabolites isolated from selected marine-derived actinobacteria strains belong to Streptomyces genus MINISTRY OF EDUCATION VIETNAM ACADEMY AND TRAINING OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY ----------------------------- CAO DUC TUAN PROJECT STUDY ON ANTIMICROBIAL SECONDARY METABOLITES ISOLATED FROM SELECTED MARINE- DERIVED ACTINOBACTERIA STRAINS BELONG TO STREPTOMYCES GENUS Major: Organic Chemistry Code: 9.44.01.14 SUMMARY OF ORGANIC CHEMISTRY DOCTORAL THESIS HA NOI – 2020 This project was completed at Graduate University Science and Technology – Vietnam Academy of Science and Technology. Scientific Advisor 1: Assoc. Prof. Doan Thi Mai Huong Scientific Advisor 2: Dr. Le Thi Hong Minh Reviewer 1: … Reviewer 2: … Reviewer 3: …. The thesis will be defended at Graduate University of Science and Technology – Vietnam Academy of Science and Technology, at: … The thesis can be found at: - The library of the Graduate University of Science and Technology, Vietnam Academy of Science and Technology. - The National Library of Vietnam. 1 INTRODUCTION 1. Basic of the thesis Natural resources have been used as drugs, additives and poisons for a long time (Marderosian, 1969). To date, natural products, most of them from terrestrial, play a major role in pharmaceutical industries (Harvey, 2000). Although, oceans accounted for about 70% of earth surface, proved to be very high biodiversity, researches on marine natural products only started recently (Fattorusso, 2012). There are over 30,000 marine natural products known to the public with diverse chemical structures and biological activities (Hu, 2011). Some reported marine natural products had structure similar to that of microorganism. It suggested that microorganism may involve in the biosynthesis of these compounds or microorganism might be the production source (Molinski, 2009). Moreover, one of the major advantages of marine microbial research is that it only requires a small amount of natural collected marine samples. Laboratory isolation, fermentation can help to produce enough material for further researches. Vietnam, situated in the tropical Pacific region with high marine biodiversity, has enormous potential in marine resources. Our government also supports the utilization of marine resources for social and economic development (Nguyễn Phú Trọng, 2018). Besides, Vietnam is one of a high antibiotic resistance prevalent country of the word (WHO, 2014). Therefore, development of new antimicrobial reagents domestically is urgently needed. Based on those reasons, project “Study on antimicrobial secondary metabolites isolated from selected marine-derived actinobacteria strains belong to Streptomyces genus” was implemented. 2. Thesis aims Searching for antimicrobial secondary metabolites from actinobacteria isolated from Vietnam marine samples: - Isolation and screening for Vietnam antimicrobial marine-derived actinobacteria strains. - Isolation and structure elucidation of compounds from 2 promising isolated actinobacteria strains. - Determination the antimicrobial activities of isolated compounds. 2 3. Main research activities 1. Isolation and culture actinobacteria strains from collected marine samples; 2. Screening the antimicrobial activities of isolated strains, select two promising strains for identification and fermentation (50L); 3. Isolation of secondary metabolites from 2 fermented strains; 4. Structure elucidation of isolated compounds; 5. Determination of antimicrobial activities of isolated compounds. CHAPTER 1. OVERVIEW 1.1. Marine biological resources 1.2. Actinomycetes 1.2.1. Classification of Actinomycetes 1.2.2. Streptomyces genus 1.2.3. Antibiotics from Streptomyces genus 1.3. Antimicrobial secondary metabolites from Streptomyces genus 1.3.1. World publications 1.3.1.1. Streptomyces sp. isolated from marine sediments 1.3.1.2. Streptomyces isolated from marine invertebrates 1.3.1.3. Streptomyces isolated from other marine sources 1.3.1.4. Antimicrobial secondary metabolites developed by marine Streptomyces sp. genome mining 1.3.2. Vietnam publications CHAPTER 2. MATERIALS AND METHODS 2.1. Materials and equipment 2.2. Research Methods 2.2.1. Sample collection methods 2.2.2. Marine actinobacteria isolation method (Williams, 1965; Williams, 1971; Vũ Thị Minh Đức, 2001) 2.2.3. Marine actinobacteria purification and storage methods (Nguyễn Lân Dũng, 2003) 3 2.2.4. Marine actinobacteria activation and fermentation methods (Vũ Thị Minh Đức, 2001; Nguyễn Lân Dũng, 2003) 2.2.5. Culture broth extraction method (Carlson, 2014; Tanouye, 2015) 2.2.6. Actinobacteria identification methods (Holt, 1989; Sambrook, 1989; Weisburg, 1991; Li, 2007) 2.2.7. Actinobacteria fermentation (50 L) method (Basilio, 2003; Nguyễn Văn Cách, 2004) 2.2.8. Secondary metabolite isolation methods 2.2.9. Structural elucidation methods 2.2.10. Antimicrobial screening method (Hadacek, 2000) CHAPTER 3. EXPERIMENT AND RESULTS 3.1. Sample collection results Using the described equipment and methods, 23 marine samples were collected, including: - 09 samples from the sea of Quang Binh (2 sediments, 3 algae, 3 soft corals and 1 sponge). - 14 samples from Cu Lao Cham, Quang Nam (5 sediments, 2 soft corals, 1 sponge, 2 echinoderms, 2 sea-rabbits, 1 snake tail and 1 invertebrate). 3.2. Actinomycete isolation results Processing 23 marine samples collected at the sea of Quang Binh a ...