Biodiversity of heterotrophic bacteria in aquatic and terrestrial microbial mats in Antarctica
Antarctica is the southernmost continent on Earth. As a result of the extreme environmental conditions, only few macroorganisms are able to survive and therefore, microorganisms make up the most important components of the food webs. Previous microbial studies reported a large diversity, including p...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Ghent University. Faculty of Sciences
2011
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| Online Access: | https://biblio.ugent.be/publication/1220438 http://hdl.handle.net/1854/LU-1220438 https://biblio.ugent.be/publication/1220438/file/4335552 |
| Summary: | Antarctica is the southernmost continent on Earth. As a result of the extreme environmental conditions, only few macroorganisms are able to survive and therefore, microorganisms make up the most important components of the food webs. Previous microbial studies reported a large diversity, including previously undescribed taxa. Despite the growing number of studies, many habitats and Antarctic regions remain unstudied. These habitats are seriously threatened by climate change and increasing human impact. The first objective was the study of the heterotrophic bacterial diversity in Antarctic microbial mats using cultivation. Therefore, seven aquatic microbial mat samples originating from various sites on the continent, and two terrestrial mat samples, originating from Utsteinen nunatak, located in close proximity to the new Princess Elisabeth Station, and taken before construction, were studied. A total of 3 806 isolates were obtained and the rep-PCR fingerprinting was used for dereplication. Representative strains were subjected to 16S rRNA gene sequence analysis which revealed a large diversity distributed over several main phylogenetic groups including an important number of potentially new taxa. For about one-third of the genera recovered, this is the first report from Antarctica. Furthermore, the cultures obtained in this study will become available for further fundamental and applied biotechnological research. Comparison with environmental sequences from public databases showed that an important number of our phylotypes are, at present, known only from Antarctica. The second objective encompassed the detailed study of the strains belonging to the genus Flavobacterium (Bacteroidetes). They showed low 16S rRNA gene sequence similarity with named Flavobacterium species. The combination of 16S rRNA gene and gyrB gene phylogeny, confirmed by phenotypic characterisation, revealed the presence of several potentially new Flavobacterium species. Only few additional tests have to be performed to describe them as new ... |
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