Title Page
Contents
Abstract 12
Chapter 1. General Introduction 14
1.1. Introduction 14
1.1.1. Antibiotics 14
1.1.2. The urgent of finding antibiotic candidates from soil 15
1.2. Objectives of the study 16
Chapter 2. Characterization of the novel species having antimicrobial activity 17
2.1. Introduction 17
2.2. Materials and methods 19
2.2.1. Location of soil and isolation 19
2.2.2. Morphological, physiological, and biochemical analysis 20
2.2.3. Phylogenetic analysis 22
2.2.4. Genome sequence analysis 23
2.2.5. Chemotaxonomic characteristics 23
2.3. Results 24
2.3.1. Morphological, physiological, and biochemical analysis 24
2.3.2. Phylogenetic analysis 26
2.3.3. Genome sequence analysis 29
2.3.4. Chemotaxonomic characteristics 32
2.3.5. Description of novel bacteria YJM1T[이미지참조] 35
2.4. Conclusion 37
Chapter 3. Analysis of Burkholderia sp. MKH5-5 as an antibiotic producer 38
3.1. Introduction 38
3.2. Materials and methods 40
3.2.1. Biological characteristics of Burkholderia diffusa MKH5-5T[이미지참조] 40
3.2.2. Fermentation and Extraction 40
3.2.3. Antibiotic activity of crude extract 40
3.2.4. Prediction of secondary metabolism based on genome sequence 41
3.2.5. Purification of antibiotic extraction by silica gel column chromatography 41
3.2.6. antimicrobial test with separate fractions 42
3.2.7. Minimum inhibitory concentration 42
3.3. Results 43
3.3.1. Biological characteristics of Burkholderia diffusa MKH5-5T[이미지참조] 43
3.3.2. Prediction of Secondary Metabolism based on genome sequence 48
3.3.3. Antibiotic activity of crude extract 49
3.3.4. Thin-Layer (TLC) and column chromatography assay 50
3.3.5. Minimum inhibitory concentration (MIC) 53
3.4. Conclusion 54
References 55
국문요지 62
〈Table 2-1〉 Phenotypic characteristics of strain YJM1T and the closely related members of the genus Arthrobacter. Strains : 1, YJM1T, 2,...[이미지참조] 25
〈Table 2-2〉 General genomic features of strain YJM1T[이미지참조] 30
〈Table 2-3〉 The distribution of biosynthetic gene clusters (BGCs) in strain YJM1T. Butyrolactone, Betalactone, RRE-containing, NAPAA.[이미지참조] 31
〈Table 2-4〉 Average nucleotide identity (ANIu) and digital DNA-DNA hybridization (dDDH) between strain YJM1T and phylogenetically closest...[이미지참조] 31
〈Table 2-5〉 Fatty acid profiles of strain YJM1T and related species of the genus Arthrobacter. Strain: 1, YJM1T ; 2, YJM12S; 3, Arthrobacter...[이미지참조] 33
〈Table 3-1〉 Morphological characteristics of colonies of strain Burkholderia diffusa MKH5-5 43
〈Table 3-2〉 General genome features of Burkholderia diffusa MKH5-5. 45
〈Table 3-3〉 The prediction of secondary metabolites regions making gene cluster by antiSMASH version 6.0 from WGS of Burkholderia diffusa MKH5-5. 48
〈Table 3-4〉 Crude extract and fractions inhibition zone size on antimicrobial test. Methanol was used as negative control. -; negative 50
〈Table 3-5〉 MIC values of extract with antibiotics 53
〈Figure 2-1〉 Transmission electron photomicrograph of strain YJM1T grown on R2A agar at 30℃ for 12 hours. Bar, 500 nm.[이미지참조] 24
〈Figure 2-2〉 Neighbor-joining phylogenetic tree using 16S rRNA sequences of YJM1T related species of the family Micrococcaceae. The numbers at the...[이미지참조] 27
〈Figure 2-3〉 Phylogenetic tree based on whole genome sequence comparing of YJM1T and related species. The whole genome sequence tree was...[이미지참조] 28
〈Figure 2-4〉 Subsystem feature of strain YJM1T revealed by RAST (Rapid Annotation using Subsystem Technology) server.[이미지참조] 30
〈Figure 2-5〉 Polar lipid profile of strain YJM1T using molybdatophosphoric acid as spray reagent. DPG: diphosphatidylglycerol, PG: phosphatidylglycerol,...[이미지참조] 34
〈Figure 3-1〉 Workflow of obtaining antibiotic materials 39
〈Figure 3-2〉 Growth curve of strain MKH5-5 44
〈Figure 3-3〉 Neighbor-joining phylogenetic tree using 16S rRNA sequences of MKH5-5 related species of the genus Burkholderia. The numbers at the... 46
〈Figure 3-4〉 Phylogenetic tree based on whole genome sequence comparing of MKH5-5 and related species. The whole genome sequence tree was... 47
〈Figure 3-5〉 Genome map of strain MKH5-5. 47
〈Figure 3-6〉 Crude extract antimicrobial test of MKH5-5 with B. subtilis and C. albicans (156 µg/mL). 49
〈Figure 3-7〉 Fractions antimicrobial test of MKH5-5 with B. subtilis and C. albicans (156 µg/ml). 49
〈Figure 3-8〉 Separation by ethyl-acetate: hexane solvent on TLC. Spots were checked under UV light (254 nm). 51
〈Figure 3-9〉 Fractions antimicrobial test of MKH5-5 with B. subtilis and C. albicans (156 µg/mL). 52