Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica
Antarctica is a pristine region on Earth that is well known for its extreme environmental conditions. The limited distribution of microbes shaped by the biogeography of Antarctica might promote the development of endemic microbial populations and evolution of endemic taxa with unique cold-adap...
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| Format: | Thesis |
| Language: | English |
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2014
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| Online Access: | http://psasir.upm.edu.my/id/eprint/75418/1/FPSK%28M%29%202014%2024%20IR.pdf |
| _version_ | 1825950462511153152 |
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| author | Chu, Pek Lim |
| author_facet | Chu, Pek Lim |
| author_sort | Chu, Pek Lim |
| collection | UPM |
| description | Antarctica is a pristine region on Earth that is well known for its extreme environmental
conditions. The limited distribution of microbes shaped by the biogeography of
Antarctica might promote the development of endemic microbial populations and
evolution of endemic taxa with unique cold-adaptation and survival strategies in the
harsh environment. Actinobacteria is one of the dominant soil inhabitants in the
Antarctic continent. A total of 15 soil samples were collected from different sites of
Greenwich Island and Dee Island to investigate the distributions of actinobacteria in the
soil and to reveal their biosynthesis potential. Molecular screening for actinobacteria
was achieved by amplifying the large insert stretch specifically found in the 23S rRNA
gene of Actinobacteria. A selective isolation approach enabled 36 actinobacteria isolates
of ten different genera to be successfully recovered. The highest diversity and abundance
of actinobacteria was harboured in slightly alkaline soil (62.5%), compared to the
moderately alkaline soil (26.8%) and extremely alkaline soil (10.7%). The major
representatives of Actinobacteria belong to the genera Streptomyces, Micrococcus,
Kocuria and Micromonospora. Phylogenetic analysis revealed that one presumptive new
species of Micromonospora was isolated (98.8% 16S rRNA gene sequence similarity).
Through the PCA analysis, water availability which serves as a dynamic source for the
interactions of microbes was examined as the principal factor that shaped the
distribution of actinobacteria from Greenwich Island and Dee Island. The presence of
the biosynthetic systems polyketide synthase (PKS) and non-ribosomal peptide synthase
(NRPS) in the genomes of the actinobacteria isolates indicated their great biosynthesis
potential. In the expression analysis, the bioactive compounds recovered in ethyl acetate
extracts were showing antibacterial activity against a broad spectrum of Gram-positive
and Gram-negative pathogenic bacterial strains. The best group of antibacterial
producers was the actinobacteria isolated from highly alkaline soil (>pH8.5), which
exhibited 19.5% higher antibacterial activity than the next group of isolates from
moderately alkaline soil (pH 7.9-8.4). The random amplified polymorphic DNA (RAPD)
analysis was capable of detecting the intra-specific genetic variations among the 11
Streptomyces species and generated a specific cluster of Streptomyces albidoflavus.
Other than taxonomic classification, RAPD is also capable of segregating the actinobacteria isolates into clusters having specific antibacterial patterns. Antarctica has
emerged as a natural reservoir of actinobacteria with great biosynthesis potential for
bioprospecting. |
| first_indexed | 2024-03-06T10:14:58Z |
| format | Thesis |
| id | upm.eprints-75418 |
| institution | Universiti Putra Malaysia |
| language | English |
| last_indexed | 2024-03-06T10:14:58Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | upm.eprints-754182019-11-21T08:41:28Z http://psasir.upm.edu.my/id/eprint/75418/ Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica Chu, Pek Lim Antarctica is a pristine region on Earth that is well known for its extreme environmental conditions. The limited distribution of microbes shaped by the biogeography of Antarctica might promote the development of endemic microbial populations and evolution of endemic taxa with unique cold-adaptation and survival strategies in the harsh environment. Actinobacteria is one of the dominant soil inhabitants in the Antarctic continent. A total of 15 soil samples were collected from different sites of Greenwich Island and Dee Island to investigate the distributions of actinobacteria in the soil and to reveal their biosynthesis potential. Molecular screening for actinobacteria was achieved by amplifying the large insert stretch specifically found in the 23S rRNA gene of Actinobacteria. A selective isolation approach enabled 36 actinobacteria isolates of ten different genera to be successfully recovered. The highest diversity and abundance of actinobacteria was harboured in slightly alkaline soil (62.5%), compared to the moderately alkaline soil (26.8%) and extremely alkaline soil (10.7%). The major representatives of Actinobacteria belong to the genera Streptomyces, Micrococcus, Kocuria and Micromonospora. Phylogenetic analysis revealed that one presumptive new species of Micromonospora was isolated (98.8% 16S rRNA gene sequence similarity). Through the PCA analysis, water availability which serves as a dynamic source for the interactions of microbes was examined as the principal factor that shaped the distribution of actinobacteria from Greenwich Island and Dee Island. The presence of the biosynthetic systems polyketide synthase (PKS) and non-ribosomal peptide synthase (NRPS) in the genomes of the actinobacteria isolates indicated their great biosynthesis potential. In the expression analysis, the bioactive compounds recovered in ethyl acetate extracts were showing antibacterial activity against a broad spectrum of Gram-positive and Gram-negative pathogenic bacterial strains. The best group of antibacterial producers was the actinobacteria isolated from highly alkaline soil (>pH8.5), which exhibited 19.5% higher antibacterial activity than the next group of isolates from moderately alkaline soil (pH 7.9-8.4). The random amplified polymorphic DNA (RAPD) analysis was capable of detecting the intra-specific genetic variations among the 11 Streptomyces species and generated a specific cluster of Streptomyces albidoflavus. Other than taxonomic classification, RAPD is also capable of segregating the actinobacteria isolates into clusters having specific antibacterial patterns. Antarctica has emerged as a natural reservoir of actinobacteria with great biosynthesis potential for bioprospecting. 2014-12 Thesis NonPeerReviewed text en http://psasir.upm.edu.my/id/eprint/75418/1/FPSK%28M%29%202014%2024%20IR.pdf Chu, Pek Lim (2014) Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica. Masters thesis, Universiti Putra Malaysia. Actinobacteria - isolation & purification Actinobacteria - chemistry Actinobacteria - genetics |
| spellingShingle | Actinobacteria - isolation & purification Actinobacteria - chemistry Actinobacteria - genetics Chu, Pek Lim Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica |
| title | Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica |
| title_full | Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica |
| title_fullStr | Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica |
| title_full_unstemmed | Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica |
| title_short | Isolation, molecular characterisation and bioprospecting of actinobacteria from Greenwich Island and Dee Island, Antarctica |
| title_sort | isolation molecular characterisation and bioprospecting of actinobacteria from greenwich island and dee island antarctica |
| topic | Actinobacteria - isolation & purification Actinobacteria - chemistry Actinobacteria - genetics |
| url | http://psasir.upm.edu.my/id/eprint/75418/1/FPSK%28M%29%202014%2024%20IR.pdf |
| work_keys_str_mv | AT chupeklim isolationmolecularcharacterisationandbioprospectingofactinobacteriafromgreenwichislandanddeeislandantarctica |