| 1. |
- Aevarsson, Arnthór, et al.
(författare)
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Going to extremes - a metagenomic journey into the dark matter of life
- 2021
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Ingår i: FEMS Microbiology Letters. - : Oxford University Press (OUP). - 1574-6968. ; 368:12
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Forskningsöversikt (refereegranskat)abstract
- The Virus-X-Viral Metagenomics for Innovation Value-project was a scientific expedition to explore and exploit uncharted territory of genetic diversity in extreme natural environments such as geothermal hot springs and deep-sea ocean ecosystems. Specifically, the project was set to analyse and exploit viral metagenomes with the ultimate goal of developing new gene products with high innovation value for applications in biotechnology, pharmaceutical, medical, and the life science sectors. Viral gene pool analysis is also essential to obtain fundamental insight into ecosystem dynamics and to investigate how viruses influence the evolution of microbes and multicellular organisms. The Virus-X Consortium, established in 2016, included experts from eight European countries. The unique approach based on high throughput bioinformatics technologies combined with structural and functional studies resulted in the development of a biodiscovery pipeline of significant capacity and scale. The activities within the Virus-X consortium cover the entire range from bioprospecting and methods development in bioinformatics to protein production and characterisation, with the final goal of translating our results into new products for the bioeconomy. The significant impact the consortium made in all of these areas was possible due to the successful cooperation between expert teams that worked together to solve a complex scientific problem using state-of-the-art technologies as well as developing novel tools to explore the virosphere, widely considered as the last great frontier of life.
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| 2. |
- Skirnisdottir, Sigurlaug
(författare)
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Phylogenetic characterization of microbial mats and isolation of Thermus spp. and sulfur-oxidizing bacteria from Icelandic hot springs
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Until recently, the only way to describe microbial communities was by cultivation. This is a major obstacle because typically only a small fraction of the microbes can be cultivated by standard techniques. However, the use of rRNA and molecular phylogenetic techniques has allowed us to bypass this limitation. In this thesis, both of these approaches were used to describe the bacterial diversity of a few Icelandic hot springs. One of these hot springs was a sulfide rich hot spring (sulfur-mat), which was of special interest because it had a great biomass above the photosynthetic border. In order to evaluate the abundance and stability of cultivable Thermus spp. as a function of seasonal changes in this hot spring, fifty strains of Thermus were isolated during one and a half-year period. Multilocus enzyme electrophoresis (MEE) was used to identify the Thermus strains and to examine the genetic structure of the population. The majority of the strains were T. oshimai and that population showed temporal variation. Furthermore, estimation of the association index indicated that recombination events were frequent within the population. A similar study of the population structure of the genus Thermus, within and between geothermal areas in Iceland, indicated that there were some geographical variations and some physiological factors like pH that affect the population structure of Thermus in Iceland. A new sulfur-oxidizing Thermus strain was isolated and characterized from this same hot spring. A new Hydrogenobacter strain that was able to grow on thiosulfate but could not utilize hydrogen was also isolated. These metabolic features were previously unknown for these genera. An examination of the microbial diversity of the sulfur-mat, a Chloroflexus-mat and a bacterial mat at 88°C by sequencing of SSU rRNA genes obtained by PCR and cloning from the microbial mats, showed that the population structure was quite different in these three ecosystems. Furthermore, the overall diversity of the sulfur-mat and the 88°C mat was lower than in the Chloroflexus-mat, which may be explained by more extreme physiochemical features in the sulfur-mat and the 88°C mat. Although, representatives of novel divisions were found, the majority of the sequences were >95% related to currently known sequences. Comparison of the present results to published data, indicated that there was a relationship between mat type and composition of Aquificales on one hand, and temperature and sulfide concentration on the other hand.
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| 3. |
- van der Meer, Marcel T. J., et al.
(författare)
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Distribution and isotopic composition of bacterial lipid biomarkers in microbial mats from a sulfidic Icelandic hot spring
- 2008
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Ingår i: Organic Geochemistry. - : Elsevier BV. - 1873-5290 .- 0146-6380. ; 39:8, s. 1015-1019
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Tidskriftsartikel (refereegranskat)abstract
- Green, nonsulfur-like bacteria (GNSLB) and cyanobacteria form major components of microbial mats in both sulfidic and non-sulfidic hot springs and have been mainly studied in hot springs of Yellowstone National Park (YNP). These organisms synthesize specific lipid biomarkers Such as wax esters and long chain polyunsaturated alkenes (GNSLB) and heptadecane (cyanobacteria). We analyzed the lipid distribution and their stable carbon isotopic composition in sulfidic Icelandic hot spring microbial mats known to contain GNSLB and cyanobacteria. Based on the lipid distribution, it seems that the GNSLB in these mats are closely related to Chloroflexus aurantiacus. The stable carbon isotopic composition of the bulk biomass and wax esters suggests mainly autotrophic growth by GNSLB in this sulfidic hot spring. However, the stable carbon isotopic composition of hentriacontatriene in the two GNSLB mats suggests an alternative carbon source for the C-31:3 alkene producing GNSLB from that in YNP. The isotopic composition of cyanobacterial biomarkers in the mat most distant from the source of the hot spring seems to suggest inorganic carbon limitation for cyanobacteria, possibly because they grow underneath the GNSLB in these sulfidic hot spring inverted microbial mats. (c) 2008 Elsevier Ltd. All rights reserved.
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