Fatty Acid Profile of Juvenile Arctic Char (Salvelinus alpinus Complex) from Natural Ecosystems and Aquaculture.

Significant differences in the fatty acid composition of the muscle tissue of juvenile Arctic char Salvelinus alpinus (Linnaeus, 1758) from the natural habitat (Lake Sobach'e) and aquaculture, as well as juveniles of the anadromous form of char (malma) Salvelinus malma (Walbaum, 1792) from the Avacha River were found. The observed differences between aquaculture and wild juvenile char were associated with different food sources. The muscle tissue of juvenile char from natural habitat was characterized by significantly higher levels of fatty acids-biomarkers of diatoms, as well as biomarkers of marine copepods in the anadromous form. In the fatty acid composition of juvenile char from aquaculture, significantly higher levels of linoleic acid were revealed, as well as long-chain monounsaturated acids, the source of which could be aquaculture feed. The identified differences did not have a significant effect on the content of eicosapentaenoic and docosahexaenoic acids in the muscle tissue of juvenile aquaculture and wild char. The content of biochemically valuable omega 3 polyunsaturated fatty acids in juvenile char from natural ecosystems and aquaculture was similar.

Isotope Composition of Nitrogen and Stoichiometric Ratios of Elements in Biomass of Spirogyra in Lake Baikal.

Using stable isotope analysis of nitrogen, for the first time the hypothesis on different sources of inorganic nutrients for two groups of littoral algae in Lake Baikal was confirmed. Strongly attached filamentous algae of genus Ulothrix, which developed in the wave-braking zone at depth 0.5 m, and loosely attached filamentous algae of genus Spirogyra, which developed in deeper layers 3.0-5.0 m in a low-turbulence zone, get inorganic nutrients presumably from surface discharge and groundwater inputs, respectively. Besides, stoichiometric ratios C:N and N:P in biomass of the algae indicated that growth of Spirogyra in Lake Baikal was likely limited by nitrogen, while growth of Ulothrix was limited by phosphorus.

Fatty acid composition of fish species with different feeding habits from an Arctic Lake.

We compared the composition and content of fatty acids (FAs) in fish with different feeding habits (sardine (least) cisco Coregonus sardinella, goggle-eyed charr (pucheglazka) form of Salvelinus alpinus complex, humpback whitefish Coregonus pidschian, broad whitefish Coregonus nasus, boganid charr Salvelinus boganidae, and northern pike Esox lucius from an Arctic Lake. Feeding habits of the studied fish (planktivore, benthivore, or piscivore) significantly affected the composition of biomarker fatty acids and the ratio of stable isotopes of carbon and nitrogen in their biomass. The hypothesis on a higher content of eicosapentaenoic and docosahexaenoic acids in the fish of higher trophic level (piscivores) when compared within the same taxonomic group (order Salmoniformes) was confirmed.

[Influenza virus reproduction in the MDCK cells adapted to growth in serum-free Hybris-2 medium].

Whether the MDCK cell line might adapt to grow in serum-free Hybris-2 medium and influenza viruses might be reproduced in the adapted cells was studied. Seventeen passages using the Hybris-2 medium yielded cells adapted to growth in this medium (MDCK-BS). The reproduction of influenza A (H1N1 and H3N2) and B viruses versus the cells cultured in Eagle's medium was studied. The laboratory strain of influenza A/Aichi/1/68 (H3N2) and the strain B/Ohio/01/05 of influenza B in equal titers were shown to be reproduced in both control cells on Eagle's medium and MDCK-BS cells adapted to growth in the Hybris-2 medium. The reproduction of the strains A/Brisbane/10/07 (H3N2) and A/Solomon Islands/3/06 (H1N1) was less active in the MDCK cells. Each strain of influenza viruses displayed varying infective activities. The developed serum-free Hybris-2 medium may be used for cultivation of monolayer continuous MDCK cells and for their reproduction of influenza A and B viruses.