BACTERIAL BIODIVERSITY OF THE GASTROPOD NACELLA CONCINNA AND BOTTOM SEDIMENTS IN THE WATER AREA OF THE WILHELM ARCHIPELAGO, WEST ANTARCTICA
Berezkina A.1,2 Kharkhota М.3 Kot Yu.2 Utevsky А.1,2
1 State Institution National Antarctic Scientific Center,
Ministry of Education and Science of Ukraine
2 V.N. Karazin Kharkiv National University
3 D.K. Zabolotny Institute of Microbiology and Virology of the NAS of Ukraine
Department of antibiotics
Antarctica has the highest proportions of endemic and new species of any continent. For example, endemism may reach 90% of the fish fauna on the Antarctic shelf. Increase in the scientific knowledge of Antarctic biodiversity is a priority research area for the international Antarctic community. The most widespread and numerous Antarctic species is the mollusc Nacella concinna, which is known for its microscopic mollusc-associated yeast such as Cryptococcus laurentii and Rhodotorula mucilaginosa. The bacterial associates of the Antarctic limpet have not been studied before, and this is a gap in the knowledge of the scientists.
Therefore, the aim of our work was to study the bacterial biodiversity of the Antarctic limpet (the water area of the Wilhelm Archipelago, West Antarctica). 29 isolated and purified bacterial cultures from N. concinna samples were studied using molecular genetic methods such as 16S rRNA barcoding, as well as confocal microscopy.
Mollusc-associated bacteria belong to marine Proteobacteria (Pseudoalteromonas, Psychrobacter, Psychromonas, Shewanella, Cobetia), Firmicutes (Oceanobacillus) and Bacteroidetes (Bizionia).
Phylogenetic analyses of the studied strains (Maximum Likelihood approach) based on sequences of the parts of the 16S rRNA gene revealed that bacterial strain 16c/2 belonged to the Bizionia genus, clustering with the strain of Bizionia berychis that was isolated from splendid alfonsino (Beryx splendens) collected from the North Pacific Ocean. Bacterial strain 5c/2 formed a clade with Cobetia crustatorum, which was isolated from jeotgal, a traditional Korean fermented seafood, and strain 9b/1 combined with halophilic strain Oceanobacillus picturae that was collected from a glacial moraine in Qaanaaq, Greenland. AA1/1, AA1/7 and AA1/9 strains clustered with the Pseudoalteromonas arctica, which was isolated from seawater samples collected from Spitzbergen island in the Arctic. Strain 8b/2 formed a clade with Psychromonas arctica that associated with sea ice from four permanently cold fjords of Spitzbergen, Arctic Ocean.
Obtained dendrogramm demonstrated that the N. concinna-associated strains are closely related to the bacteria inhabiting the North Pole, and some may not only have a bipolar distribution, but probably are also cosmopolitan.