Bacterial diversity of Antarctic samples through cultivation

The microbial diversity on Antarctica is largely unknown. As part of the AMBIO-project, five samples from different regions were investigated. Two gravel samples BB50 and BB115 (Utsteinen, Dronning Maud Land) and three littoral samples TM2, TM4 (Transantarctic Mountains) and PQ1 (Pourquoi-pas Island) were used. Samples were investigated with a culture-dependent approach. Dilution series were plated on four media and incubated at three temperatures. After obtaining pure cultures, rep-PCR technique was used for dereplication. Representatives of each rep-cluster were used in partial 16S rDNA sequencing to obtain a first approximate identification. The preliminary results show a large diversity, distributed over the major phylogenetic groups. The BB samples, TM4 and PQ1 were dominated by isolates of the class of Actinobacteria, most TM2 isolates belong to the Firmicutes class. In addition, for all samples, isolates from the Bacteroidetes and Proteobacteria classes were recovered. Despite the large diversity and the fact that some samples originate from the same general area, only little overlap between the samples was observed. Some of the isolated clusters show low similarity values with neighbouring sequences in the EMBL-database and may represent new species or even new genera.