Doklady Biological Sciences最新文献

Continuous artificial lighting (24LD) was introduced experimentally in the standard technology to grow salmon juveniles in a southern region (Republic of North Ossetia-Alania) and its effect on fatty acid (FA) composition of total lipids in muscles and the liver was assessed in parr and smolts of the Atlantic salmon Salmo salar L. Changes in the key FA were observed in the FA spectrum of fish, indicating that smoltification was complete and that smolts were ready for new habitat conditions. Thus the content of polyunsaturated FAs (PUFAs) significantly increased as a result of an increase in (n-3) PUFAs, and, in particular, marine-type 22:6(n-3), and high values were observed for (n-3)/(n-6) and 22:6(n-3)/18:3(n-3) PUFA ratios. The most significant changes were detected in muscles. In all experimental groups, a decrease in saturated FAs (SFAs) and an increase in total lipid unsaturation was attributed primarily to PUFAs, while monounsaturated FAs (MUFAs) decreased along with SFAs. The experimental data on the lipid and FA composition in salmon juveniles and a higher proportion of smolts in the test groups indicated that smoltification was the most successful in groups with continuous lighting and 24-h feeding and a natural regime of lighting and feeding.

The microalga Nitzschia cf. thermaloides was found in reservoirs of mud volcanoes in eastern Crimea. The species was observed to have a wide range of halotolerance and, in particular, to be capable of vegetative reproduction within a substrate salinity range of 0-110‰. The effect of salinity on the fatty acid (FA) profile was for the first time studied in N. cf. thermaloides. The quantitative and qualitative FA composition remained unchanged regardless of salinity, suggesting maintenance of a stable compacted membrane structure, which probably contributes to the species adaptation to salinity. Saturated FAs accounted for a major portion of total FAs, and the species was therefore assumed to provide a potentially valuable source of saturated FAs for biotechnology and an alternative raw material for biofuel.

An Erratum to this paper has been published: https://doi.org/10.1134/S0012496623050034

An Erratum to this paper has been published: https://doi.org/10.1134/S0012496623050071

A spore and pollen research was performed for the first time to study the contents of the gastrointestinal tracts (GITs) and sediments containing frozen mummies of the fossil Don hare from the Upper Pleistocene ice complex of the Verkhoyansk district of Yakutia. Radiocarbon dating (C¹⁴) revealed that the hares lived during the Karginian Interstadial of the Late Pleistocene, 32.5 thousand years ago (calibrated date). The results expanded the understanding of the ecology of extinct Lepus tanaiticus. The species was assumed to live in cold steppes dominated by xerophytic communities, as well as in grass-forb and sedge-forb meadows. Herbaceous plants mostly constituted the winter diet of Don hare in contrast to the modern mountain hare L. timidus, which feeds mainly on branches and bark of trees and shrubs in winter.

Activities of enzymes of energy and carbohydrate metabolism in muscles and the liver were studied in Atlantic salmon Salmo salar L. smolts and parr grown under continuous or natural lighting and different feeding regimens in autumn followed by a short photoperiod in winter. Enzyme activities were found to differ between test and control salmon groups and between parr and smolts sampled at the end of the winter period. Smolts grown under continuous lighting and round-the-clock feeding differed from other groups by having higher cytochrome c oxidase (COX) activity and lower aldolase activity in muscles. Differences in aerobic metabolism in muscles between parr and smolts were found to be the same in all experimental groups, COX and aldolase activities being relatively higher in smolts. The pattern of changes in enzyme activities in the liver from parr to smolts differed between different experimental groups. Based on the results, the photoperiod was assumed to affect the activities of energy metabolism enzymes in salmon juveniles and may eventually affect the completion of smoltification.

Gene editing using the CRISPR/Cas9 system provides new opportunities to treat human diseases. Approaches aimed at increasing the efficiency of genome editing are therefore important to develop. To increase the level of editing of the CXCR4 locus, which is a target for gene therapy of HIV infection, the Cas9 protein was modified by introducing additional NLS signals and ribonucleoprotein complexes of Cas9 and guide RNA were stabilized with poly-L-glutamic acid. The approach allowed a 1.8-fold increase in the level of CXCR4 knockout in the CEM/R5 T cell line and a 2-fold increase in the level of knock-in of the HIV-1 fusion peptide inhibitor MT-C34 in primary CD4⁺ T lymphocytes.

Examination of 14 lake-type water bodies at various latitudes of the Northern Hemisphere showed that the efficiency of phytoplankton production transformation through heterotrophic bacterioplankton and non-predatory zooplankton to predatory zooplankton and planktivorous fish increases in the direction from eutrophic to oligotrophic water bodies. The highest ratios between autotrophic and heterotrophic organism production were observed in lakes and reservoirs where the contribution of allochthonous substances to the total energy flow is relatively high. Bacterioplankton utilizing allochthonous dissolved organic matter (DOM) provides an additional source of energy for zooplankton, which serves as food for planktivorous fish. Therefore, to predict the total biological productivity and production of the fish community, it is necessary to take into account the production of not only autotrophic plankton, but also that part of heterotrophic bacterioplankton that is specialized in utilizing DOM entering the water body from the outside.

For the first time, using GPS-GSM trackers, long-term seasonal flights of greater noctule bat (Nyctalus lasiopterus) from summer habitats in Russia to wintering areas in Europe are recorded. One of the seasonal migratory flights is a record distance for bats (2515 km). The maximum daily flight was 445 km. One of the animals abruptly changed the direction of migration from southwest to north on the third day of flight after crossing the Kursk magnetic anomaly.

The ¹³C and ¹⁵N isotope contents in collagen were determined in bones of the small cave bear Ursus (Spelaearctos) rossicus Borissiak, 1930 from three regions of Western Siberia. The bones dated back to marine isotope stage (MIS) 3 and belonged to mature males and females. Some of the samples differed only in δ¹⁵N. Bears of all samples were from the same trophic level. Trophic shifts were observed between females and males in one region and between males of two regions. The small cave bear of Western Siberia differed from the small cave bear of the Southern Urals in leading a much more predatory lifestyle. The extent of differences between the Ural and Siberian bears corresponded to different trophic levels.