Meteorites were not acknowledged as truly extraterrestrial until in the 19th century. In this report, the ability of organisms to colonize meteorites was examined with classical and molecular biological methods. A table of organisms found on meteorites was constructed from published data and compared with phylogenetic trees based on a molecular biological database containing small subunit ribosomal gene sequences from different meteorite studies. Statistical analyzes between the southern and northern hemisphere were made using Mann-Whitney U test on the data in the table of organisms. Microbiological growth was also examined on the surface of four different meteorites from the desert of Oman. Twenty-one isolates were selected for further characterization of gram-properties, microscopy and fluorescence in situ hybridization (FISH). The table of organisms contains a wide variety of organisms associated with meteorites, e.g. angiosperms, lichens and different types of microorganisms. The phylogenetic trees for all three domains show that most gene sequences obtained from so far published studies belong to several different phyla. The FISH results of own experiments showed that 62 % of the 21 isolates belong to Actinobacteria, 9 % to Firmicutes and 5 % to Betaproteobacteria. The statistical analysis shows that there is no significant difference between the southern and the northern hemisphere. The number of studies is however too low to allow proper conclusions about correlations between meteorites and colonizing organisms, though the results so far suggest that organisms associated with meteorites often represent novel, unknown genera.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-137448 |
| Date | January 2017 |
| Creators | Olsson, Jenny |
| Publisher | Umeå universitet, Institutionen för ekologi, miljö och geovetenskap |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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