Abstrakt

The Polish Arctowski Station is situated in the maritime Antarctic on the western shore ot' Admiralty Bay and encompasses terrestrial habitats which are not perma-nently covered by ice, in contrast to morę than 90% of the island's surface area. Over the past several decades, stud-ies exploring the soils of those habitats have revealed a considerable diversity of bacteria, filamentous fungi, and, to a lesser extent, yeasts; however, characterization of this complex microbiome, especially at the rnolecular level, is still far from satisfactory. The isolates were assigned to their respective genera and species based on genetic analy-sis of the D1/D2 and ITS1-5.8S-ITS2 regions of rDNA. In the studied soil samples, the most abundant microorgan-isms belonged to the genera Cryptococcus, Rhodotorula, and Debaryomyces. Physiological and biochemical analy-sis of Cryptococcus gilvescens (pro tempore Gojfeauzyma gihescens) and Rhodotorula mucilaginosa showed only a limited level of intraspecies diversity. Cellular DNA con-tent and karyotypes were determined using flow cytometry and pulsed-field gel electrophoresis for several selected strains. For the first time, genome size and electrophoretic karyotypes were investigated in C. gihescens (pro tem G. gihescens), Cryptococcus saitoi (pro tem Naganiskia globosa), Cryptococcus gastricus (pro tem Gojfeauzyma gastrica), and Cryptococcus albidus (pro tem Naganishia albida). In addition, plate tests showed Antarctic yeasts to be a potential source of biotechnologically important en/.ymes. This study in biodiversity, presenting physiologi¬cal and rnolecular characterization of psychrotolerant yeast strains isolated from the soils of western Admiralty Bay, contributes to a better understanding of the microbial ecol-ogy of this uniąue ecosystem.

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