Characterisation of yeasts isolated from deep igneous rock aquifers of the Fennoscandian Shield
| Autor: | A. H. O'Neill, Elisabeth Thomsson, Susanne Ekendahl, Karsten Pedersen |
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| Rok vydání: | 2003 |
| Předmět: |
Microorganism
Soil Science Fresh Water Biology Environment Sodium Chloride Microbial ecology Most probable number Yeasts Botany Extreme environment Ribosomal DNA Ecology Evolution Behavior and Systematics Phylogeny Sweden Ecology Models Genetic Sequence Analysis RNA Temperature Biodiversity Hydrogen-Ion Concentration Adaptation Physiological Yeast Microscopy Electron Microbial population biology RNA Ribosomal Water Microbiology Groundwater |
| Zdroj: | Microbial ecology. 46(4) |
| ISSN: | 0095-3628 |
| Popis: | The diversity of prokaryotes in the groundwater deep below the surface of the Baltic Sea at the Aspo Hard Rock Laboratory (HRL) in southeast Sweden is well documented. In addition, there is some evidence that eukaryotes, too, are present in the deep groundwater at this site, although their origins are uncertain. To extend the knowledge of eukaryotic life in this environment, five yeast, three yeastlike, and 17 mold strains were isolated from Aspo HRL groundwater between 201 and 444 m below sea level. Phenotypic testing and phylogenetic analysis of 18S rDNA sequences of the five yeast isolates revealed their relationships to Rhodotorula minuta and Cryptococcus spp. Scanning and transmission electron microscopy demonstrated that the strains possessed morphological characteristics typical for yeast, although they were relatively small, with an average length of 3 micro m. Enumeration through direct counting and most probable number methods showed low numbers of fungi, between 0.01 and 1 cells mL(-1), at some sites. Five of the strains were characterized physiologically to determine whether they were adapted to life in the deep biosphere. These studies revealed that the strains grew within a pH range of 4-10, between temperatures of 4 degrees C and 25-30 degrees C, and in NaCl concentrations from 0 to 70 g L(-1). These growth parameters suggest a degree of adaptation to the groundwater at Aspo HRL. Despite the fact that these eukaryotic microorganisms may be transient members of the deep biosphere microbial community, many of the observations of this study suggest that they are capable of growing in this extreme environment. |
| Databáze: | OpenAIRE |
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