Early Postnatal Experience Modifies Activation of the Pituitary Testicular Complex in Male House Mice (Mus Musculus) Exposed to the Odor of Receptive Con- and Heterospecific Females.

For the first time, it was shown that activation of the pituitary-testicular complex in male house mice exposed to the odor of receptive females of their own and closely related species was modified under the influence of early postnatal experience and the maternal environment. We have confirmed associated formation of behavioral and physiological mechanisms of precopulatory isolation in early ontogenesis. The serum levels of free testosterone in males of closely related species M. spicilegus and M. m. wagneri differ, it is significantly lower in mound-building mice. In males fostered by a conspecific female, the level of free testosterone was significantly lower when exposed to a heterospecific female odor in comparison with a conspecific odor. The rearing of M. m. wagneri males by females of a closely related species led to a decrease in the testosterone response caused by exposure to female chemosignals (both con- and heterospecific) and to the absence of differences in the serum level of free testosterone when exposed to the odor of a female of their own or closely related species. These results indicate that the rearing conditions had a significant influence on the formation of hormonal mechanisms of reproductive isolation.

Mutations of the VCORC1 Gene of Resistance to Anticoagulants in Synanthropic Rodents in Urbanized Areas of Russia.

This is the first study to analyze the variability of two exons (the 1st and 3rd) of the VCORC1 gene in Russian populations of mice and rats, namely, 125 Mus musculus and 19 Rattus norvegicus captured in 13 settlements. Previously, it has been shown that a number of mutations in these exons in the countries of Western Europe are associated with resistance to anticoagulants in synanthropic rodents. We did not find such mutations in house mice in Russia. However, in the first exon, two previously unknown mutations were identified that could potentially have such an effect (Lys58Arg and Ser31Trp). In three districts of Moscow, Norway rats were found carrying in the third exon a previously known resistance mutation (Tyr139Ser) in the heterozygous state. The results are discussed in connection with the intensity of the use of anticoagulants in the settlements of Russia and the mutation rate of the VCORC1 gene.

[Variability of Fragments of Nuclear Brca1 Gene, Exon 11, and Mitochondrial Cox1 Gene in House Mice Mus musculus].

To clarify genetic differences between subspecies of the house mouse Mus musculus, their distribution, and hybridization, we first conducted a comparative analysis of variability of nucleotide sequences of fragments of the nuclear gene Brca1, exon 11 (2331 bp), and mitochondrial gene Cox1 (1260 bp) in 40 house mice from West and East Europe, Transcaucasia, Siberia, and Central and South Asia. Brca1 genotypes were divided into five main groups, which differed in a number of fixed substitutions. Genotypes of each group are characteristic for the certain geographical region and the following subspecies: M. m. musculus, M. m. domesticus, M. m. castaneus, and M. m. wagneri together with M. m. gansuensis; a fifth group corresponds to an unidentified subspecies or a distinct genetic form of M. musculus from India (Sikkim State). Besides the homozygous specimens, we revealed mice, which were heterozygous for all diagnostic loci simultaneously; these specimens were determined as hybrid. Hybrid mice were mainly found in the zones of contact of subspecies, but in some cases, quite far from one of the parent subspecies (possibly, due to transportation). In two hybrid mice (from Bakhtiari Province of Iran and Transbaikalia of Russia), unique Brca1 haplotypes were detected. It cannot be ruled out that, at least partly, they may be characteristic of the M. m. bactrianus and M. m. gansuensis subspecies, respectively. Thus, the results of the study showed that the nuclear Brca1 gene is a promising molecular genetic marker for the analysis of variability, differentiation, and hybridization of house mice as well for subspecific identification of M. musculus specimens. Despite more rapid evolution of the Cox1 gene, it is not well suited for discrimination of M. m. musculus, M. m. wagneri, M. m. gansuensis specimens and Transcaucasian representatives of M. m. domesticus due to introgression and long-term maintenance of foreign mitochondrial DNA in populations. However, Cox1 gene analysis (along with the diagnostics of animals by nuclear DNA) may be useful for estimation of population differences in M. m. castaneus and M. m. domesticus subspecies.

[Detection of Volatile Organic Compounds Associated with Hepatocellular Carcinoma by Macrosmatic Animals: Approaches to the Search for New Tumor Markers].

Macrosmatic animals (dogs and mice) have been proved to be able to distinguish between the urine or feces of mice with transplanted hepatocellular carcinoma and those of healthy mice by odor. The chemical composition of animal excreta was found to change with tumor growth; however, it is not clear yet if this results from tumor growth itself, inflammation, or immune response. We suggested that the use of the ability of macrosmatic animals to compare odor mixtures combined with mouse cancer models is a promising trend in the search for new tumor markers.

[Relationship between characteristics of sexual behavior and male sperm competitive ability in taxa of superspecies complex Mus musculus sensu lato].

Some physiological parameters that determine quality of male sperm (its concentration, spermatozoa morphology) and testicle size vary in integrity, i.e. the bigger are testicles the higher is sperm quality. Therefore, the estimate of testicles relative mass is often used as a characteristic of sperm competitive ability when comparing phylogenetically close mammal species. In house mice belonging to the superspecies complex Mus musculus s.l., testicles relative mass is greater in exoanthropic species than in synanthropic ones. It is shown in our study that this pattern is apparent also at the intraspecies level since testicles mass index, sperm concentration, and percentage of morphologically normal spermatozoa in subspecies Mus musculus wagneri, which is facultatively synanthropic, are higher compared with synanthropic subspecies M m. musculus. An analysis of sexual behavior of the three forms (namely, exoanthropic species M. spicilegus and two subspecies mentioned above) indicates that in M. spicilegus both sexual behavior efficiency and ejaculation rate during coupling were higher as compared with other two subspecies. Based on the analysis of life pattern, reproduction systems, and group spatial-ethological structure, the hypotheses are formulated that explain the maintenance of selection directed to increase of sperm competitive ability in exoanthropic house mice species.

Phylogenetic relationships of intraspecific forms of the house mouse Mus musculus: Analysis of variability of the control region (D-loop) of mitochondrial DNA.

Analysis of the control region of mitochondrial DNA (mtDNA) or D-loop of 96 house mice (Mus musculus) from Russia, Moldova, Armenia, Azerbaijan, Kazakhstan, and Turkmenistan has been used to reconstruct the phylogenetic relationships and phylogeographic patterns of intraspecific forms. New data on the phylogenetic structure of the house mouse are presented. Three phylogroups can be reliably distinguished in the eastern part of the M. musculus species range, the first one mainly comprising the haplotypes of mice from Transcaucasia (Armenia); the second one, the haplotypes of mice from Kazakhstan; and the third one, the haplotypes of mice from Siberia and some other regions. The morphological subspecies M. m. wagneri and M. m. gansuensis have proved to be genetically heterogeneous and did not form discrete phylogroups in the phylogenetic tree.

[Influence of the Mother on the Behavior of Young Rabbits during the Prepubertal Period].

In this study, we investigate the influence of a mother on the behavior of young rabbits during the prepubertal period. It is shown that the presence ofthe mother affects the ratio of types of activity in offspring and the mother can demonstrate behavioral patterns to suppress aggressive behavior in offspring. It was found that rabbits in the prepubertal period continue to have active contact with their mother and make successful attempts at sucking. It was noted that, in terms of percentage, both in the frequency and duration of different forms of activity among rabbits from one to three months of age, a neutral socially oriented and feeding behavior appear to be predominant. There were significant differences in the frequency of the socially oriented behavior and the duration of feeding behavior in young rabbits, who grew up with their mother and without her.

Distribution of the C1473G polymorphism in tryptophan hydroxylase 2 gene in laboratory and wild mice.

The neurotransmitter serotonin is implicated in the regulation of various forms of behavior, including aggression, sexual behavior and stress response. The rate of brain serotonin synthesis is determined by the activity of neuronal-specific enzyme tryptophan hydroxylase 2. The missense C1473G substitution in mouse tryptophan hydroxylase 2 gene has been shown to lower the enzyme activity and brain serotonin level. Here, the C1473G polymorphism was investigated in 84 common laboratory inbred strains, 39 inbred and semi-inbred strains derived from wild ancestors (mostly from Eurasia) and in 75 wild mice trapped in different locations in Russia and Armenia. Among all the classical inbred strains studied, only substrains of BALB/c, A and DBA, as well as the IITES/Nga and NZW/NSlc strains were homozygous for the 1473G allele. In contrast to laboratory strains, the 1473G allele was not present in any of the samples from wild and wild-derived mice, although the wild mice varied substantially in the C1477T neutral substitution closely linked to the C1473G polymorphism. According to these results, the frequency of the 1473G allele in natural populations does not exceed 0.5%, and the C1473G polymorphism is in fact a rare mutation that is possibly eliminated by the forces of natural selection.

[A study of the mechanisms of probiotic effect of Bacillus subtilis 8130 strain].

The wild-type Bacillus subtilis strain 8130 secreted metabolites that stimulated two to three times the growth of the test cultures of lactic acid bacteria. It exhibited endoglucanase activity that depended on the composition of nutrient medium. The addition of the product of two-stage culturing of B. subtilis 8130 to the diet of pigs (0.2% of fodder weight) made it possible to increase the daily weight gain by 19% and decrease the consumption of mixed fodder by 10%. Digestion of protein, fat, and other organic compounds increased by 3-4% and cellulose by 12%. It was shown that B. subtilis 8130 is a probiotic with targeted action stimulating digestion (primarily the digestion of cellulose). The enrichment of a dry-beer pellet with the product of solid-phase fermentation by bacillus (1 x 10(8) cells per gram dry pellet) allowed the pellet to entered into the diet of a calf (6% of the weight of fodder with probiotic), causing additional weight gain by 12% and a 10% economy of fodder consumption.

[Orienting-exploratory behavior: a comparative analysis of the synanthropic and wild-living forms of house mice of the superspecies complex Mus musculus s. lato]. / Orientirovochno-issledovatel'skoe povedenie: sravnitel'nyi analiz sinantropnykh i dikozhivushchikh form domovykh myshei nadvidovogo kompleksa Mus musculus s. lato.

Studies of protein polymorphism, restriction of mitochondrial DNA and karyology revealed two large, divergent groups in Mus musculus s. lato. The first group includes the commensal forms M. m. musculus, M. m. domesticus, M. m. bactrianus and some others; the second group comprises the wild species M. spretus, M. abbotti, and M. spicilegus. M. domesticus and M. musculus are very flexible in terms of ecology and consist of obligatory commensal and outdoor populations. This study was aimed at comparative analysis of exploratory behavior in commensal and wild forms of Mus musculus s. lato in terms of phylogeny in Mus musculus s. l. and evolution of commensalism. Experiments in an enclosure measuring 4 x 4 x 1.5 m ("living room") showed nine patterns of exploratory behavior in eight forms of different commensal level (3 populations of musculus, 1 domesticus, 1 musculus x domesticus, 1 praetextus, 1 spretus, and 1 spicilegus). The searching behavior of the commensal and wild living forms differed both qualitatively and quantitatively. The commensal forms investigated the entire new territory, including high objects, while the wild forms investigated mostly the floor area of the enclosure. Significant species-specific and ecological differences were found by analysis of variance (ANOVA). Three functions were obtained by discriminant analysis. This demonstrated that the vertical activity and method of making contact with new objects are different in commensal and wild forms. Exploratory behavior is very similar in wild species and wild forms of musculus. Commensal forms are more active and have a high motor activity. The "commensal" phenotype of exploratory behavior is more expressed in M. m. domesticus. Three hypotheses of the evolutionary development of the "commensal" exploratory phenotype are discussed.

[Species-specific odor in closely related species: period of development in ontogenesis of house (Mus musculus musculus) and mound-building (Mus spicilegus) mice]. / Vidospetsificheskii zapakh u blizkorodstvennykh vidov: vremia formirovaniia v ontogeneze u domovykh (Mus musculus musculus) i kurganchikovykh (Mus spicilegus) myshei.

In two-choice odor tests, it was shown that house and mound-building mice began to discriminate the species-specific odor of young at the age of 17 days. The mice investigated the odor of conspecific urine significantly longer than that of heterospecific urine, when the young donors of urine, were 17 days old or older. Thus, the species-specific odor appears in ontogenesis of these species on the 17th day of life.

[An experimental study of the mechanisms of precopulatory isolation between 3 genetic forms of the house mouse in the genus Mus]. / Eksperimental'noe izuchenie mekhanizmov prekopuliatsionnoi izoliatsii mezhdu tremia geneticheskimi formami domovykh myshei roda Mus.

Under experimental conditions, possible mechanisms of precopulatory isolation were studied in house mice of there forms: Mus musculus musculus, sympatric M. spicilegus, and allopatric hybrid population of M. m. domesticus x M. m. musculus. In these experiments, the animals were placed in pairs (a male and a female in state of estrus) on a neutral territory. Nine combinations of matching were used. No pronounced mechanisms were found to prevent the copulation of partners of different forms. The factor analysis has revealed the dependence of different forms of social interactions between potential sexual partners upon three factors: taxonomic position of female, taxonomic position of male, and variant of matching. It was shown that the behaviour of female was one principal determinant of the development of events during the experiment.