RatDEGdb: a knowledge base of differentially expressed genes in the rat as a model object in biomedical research.

The animal models used in biomedical research cover virtually every human disease. RatDEGdb, a knowledge base of the differentially expressed genes (DEGs) of the rat as a model object in biomedical research is a collection of published data on gene expression in rat strains simulating arterial hypertension, age-related diseases, psychopathological conditions and other human afflictions. The current release contains information on 25,101 DEGs representing 14,320 unique rat genes that change transcription levels in 21 tissues of 10 genetic rat strains used as models of 11 human diseases based on 45 original scientific papers. RatDEGdb is novel in that, unlike any other biomedical database, it offers the manually curated annotations of DEGs in model rats with the use of independent clinical data on equal changes in the expression of homologous genes revealed in people with pathologies. The rat DEGs put in RatDEGdb were annotated with equal changes in the expression of their human homologs in affected people. In its current release, RatDEGdb contains 94,873 such annotations for 321 human genes in 836 diseases based on 959 original scientific papers found in the current PubMed. RatDEGdb may be interesting first of all to human geneticists, molecular biologists, clinical physicians, genetic advisors as well as experts in biopharmaceutics, bioinformatics and personalized genomics. RatDEGdb is publicly available at https://www.sysbio.ru/RatDEGdb.

The physiological reaction of Siberian hamsters (Phodopus sungorus, Cricetidae) to chemical signals of perspective mating partners before and during courtship.

In this investigation we assessed the physiological reaction of hamsters in response to chemical signals from potential sexual partners, and also after a private meeting with them, which allowed us to ascertain the type of mating system for this species. The reception of olfactory signals led to an increase in peroxidase activity in the blood for both sexes, indicative of activity of a non-specific line of immune defense in recipients. The increase in blood cortisol level in response to the chemical signals of a partner was only observed in females. Males spent more time near samples of estrous females, with elevated levels of cortisol in the urine. In olfactory tests, an hour after grouping all the individuals in pairs there was a significant increase in blood peroxidase activity, which indicates the reaction of a non-specific link in the immune system of partners. This increase was greater in the pairs with a mutual preference. Females from these pairs demonstrated a substantial decrease in stress hormone levels in the plasma after an hour of mating in comparison to females prior to mating, and in non-preferred coupling.

Dynamics of testosterone concentration in male steppe lemmings (Lagurus lagurus) in the reproductive cycle reflects the species-specific mating system.

In the blood of male steppe lemmings, relatively low background levels of testosterone were detected, this is characteristic of a monogamous species. A significant increase in testosterone level, more expressed in sexually active males, was observed at the initial stage of formation of reproductive couples. Apparently, in the future, the couple will exist in a stable relationship, and, hence, the maintenance of a high testosterone level becomes excessive. The decrease in, and the relative "normalization" of, the hormone level during the existence of the pair, including raising of the young, promotes higher expression of the male paternal care of the offspring at the species level.

[Interpopulation variability of endocrine-metabolic reaction to cold stress in northern red-backed vole (Myodes rutilus)].

In natural environment, stresses, when animals happen to be exposed to them, influence the functional activity of adrenal cortex. It can be expected that in animals, living under unfavorable conditions, basal concentration of glucocorticoid hormones would be increased while adrenocortical response to acute stress would be weakened. Since the main function of stress-reaction is resources mobilization meant to compensate an environmental impact, its weakening should lead to reduction of reserve metabolic capacities. To test this hypothesis, we compared energy metabolism, body temperature, and corticosterone concentration in blood plasma measured in northern red-back voles (Myodes rutilus) before and after acute cooling in helium-oxygen mixture. Voles belonged to two populations that deffered in relative abundance. It is found out that voles from a population of low relative abundance inhabiting the recreational forest of Novosibirsk Scientific Center, despite their being more stress-prone and having weakened stress-reaction, have higher maximum metabolic rate than voles from the mountain taiga polulation with high relative abundance. The results obtained suggest that living under unfavorable conditions leads to physiological adaptations which enhance resistance to acute stress, yet increase the risk of chronic stresses that have negative effect on fitness.