Kantserova Np

Biochemical markers of pollutant responses in macrozoobenthos from the White Sea: Intracellular proteolysis

Coastal environments of Kandalaksha Gulf in the White Sea (Russia) despite nature conservation efforts are heavily influenced by human activities. Biological effects of complex environmental pollution, including organic substances, heavy metals, and oil hydrocarbons, were assessed in widely distributed marine invertebrates, Gammarus duebeni (Crustacea, Amphipoda) and Mytilus edulis (Mollusca, Bivalvia), collected from a series of anthropogenically-impacted areas and distanced reference sites in Kandalaksha Gulf. The parameters of intracellular protein degradation pathways such as cytosol calpain system and lysosomal cathepsins B (CatB) and cathepsin D (CatD) were studied. The response reactions observed in invertebrates vary in specificity and ranged from adaptive to destructive depending on the total contaminant level and the nature of predominant pollutant. The ecological relevance of studied parameters as biomarkers was confirmed by their ability to indicate both expose to pollutants and adverse effects at the organism level.

Calpain system dysregulation in rat brain at beta-amyloid-induced neurodegeneration

Experimental evidence of calcium-dependent proteolysis dysregulation in brain of the murine model of Alzheimer’s disease was obtained. Experimental treatment, consisting of intra-hippocampal injection of amyloid beta-peptide (Aβ1–40), promoted activation of main calpain forms in murine brain along with a decrease in the content of a natural calpain inhibitor, calpastatin. As a result of a prognostic experiment on the correction of neurodegeneration induced in rats, neuroprotective properties of a steroid hormone estradiol were confirmed and a possible mechanism of the protective effect was suggested. The results allow consideration of both biochemical modifications in protein facilities of a pathology-affected brain and the mechanisms of neurodegeneration and neuroprotection.

The effect of weak low-frequency magnetic fields on the intracellular calcium-dependent proteinases of fish

The in vivo and in vitro effects of weak, low-frequency magnetic fields with resonance parameters for calcium ions upon intracellular calcium-dependent proteinases (calpains) in the crucian carp (Carassiuscarassius (L.)) and roach (Rutilus rutilus (L.)) were studied. It has been revealed that the impact of a weak lowfrequency magnetic field leads to considerable decrease in the activity of calpains in the fish skeletal muscles and brain.

Protein degradation systems in the skeletal muscles of parr and smolt Atlantic salmon Salmo salar L. and brown trout Salmo trutta L.

Although protein degradation limits the rate of muscle growth in fish, the role of proteolytic systems responsible for degrading myofibrillar proteins in skeletal muscle is not well defined. The study herein aims to evaluate the role of calpains (calcium-activated proteases) and proteasomes (ATP-dependent proteases) in mediating muscle protein turnover at different life stages in wild salmonids. Protease activities were estimated in Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.) parr and smolts from the Indera River (Kola Peninsula, Russia). Calpain and proteasome activities in Atlantic salmon skeletal muscles were lower in smolts as compared with parr. Reduced muscle protein degradation accompanying Atlantic salmon parr-smolt transformation appeared to provide intense muscle growth essential for a minimum threshold size achievement that is required for smoltification. Calpain and proteasome activities in brown trout parr and smolts at age 3+ did not significantly differ. However, calpain activity was higher in smolts brown trout 4+ as compared with parr, while proteasome activity was lower. Results suggest that brown trout smoltification does not correspond with intense muscle growth and is more facultative and plastic in comparison with Atlantic salmon smoltification. Obtained data on muscle protein degradation capacity as well as length-weight parameters of fish reflect differences between salmon and trout in growth and smoltification strategies.

Ecological features of migrating passerines (analysis with molecular biology techniques involved)

The adaptation mechanisms in Phylloscopus warblers to habitat conditions associated with their reproduction, namely, the sex ratio, family structure, duration of sexual activity, etc., have been studied. The brood sex ratio is established to be about 1: 1 among juveniles, but males begin to predominate with time. In the reproductive period, some males remain unmated for a long time or even over the whole season. On the other hand, nesting males create pairs with second females. Visual observations and the results of a family structure analysis by means of molecular-genetic methods have shown that female “adultery” and/or forcible copulations with alien males occur from time to time, which leads to the appearance of extra-pair paternity. A PCR analysis revealed a high level of genetic diversity within the local populations of all the Phylloscopus warbler species, but the diversity for wood and greenish warblers (new species for the region) was lower than that for chiff-chaffs and willow warblers (species native to the region).

Skeletal muscle protease activities in the early growth and development of wild Atlantic salmon (Salmo salar L.)

Growth-related dynamics of intracellular protease activities in four year classes of the Atlantic salmon (Salmo salar L. 1758) parr and smolts inhabiting salmon rivers of northwestern Russia (the White Sea basin) were studied. Cathepsin B, cathepsin D, proteasome, and calpain activities in the skeletal muscles of salmon were assessed to investigate their relative contribution to the total protein degradation as well as to young fish growth process. It was confirmed that calpain activity dominates in salmon muscles while proteasome plays a minor role, in contrast to terrestrial vertebrates. Calpain and proteasome activities were maximal at the early post-larval stage (in parrs 0+) and declined with age (parrs 1+ through 2+) dropping to the lowest level in salmon smolts. Annual growth increments and proteolytic activities of calpains and proteasome in the muscles of salmon juveniles changed with age in an orchestrated manner, while lysosomal cathepsin activities increased with age. Comparing protease activities and growth increments in salmon parr and smolts we suggested that the partial suppression of the protein degradation could be a mechanism stimulating efficient growth in smoltifying salmon. Growth and smoltification-related dynamics of protease activities was quite similar in salmon populations from studied spawning rivers, such as Varzuga and Indera; however, some habitat-related differences were observed. Growth increments and protease activities varied in salmon parr 0+ (but not on later ages) inhabiting either main rivers or small tributaries apparently due to habitat difference on the resources for fish growth.