CD-1 mice females recognize male reproductive success via volatile organic compounds in urine.

Sexual selection is considered as one of the leading factors of evolutionary development. In the conditions of incessant competition, specialized methods of attracting individuals of the opposite sex as well as criteria for assessing the quality of a sexual partner have been formed. In order for animals to rely on signaling from sexual partners, the signal must reflect the morpho-physiological status of animals. A high reproductive efficiency of male mice is a good advantage for mate selection and thus must be somehow demonstrated to potential mates. The aim of our study was to find out if male mice could demonstrate their reproductive efficiency through urine volatile organic compounds. The experiment implies cohabiting one male with two mature females for 6 days. The reproductive success of the male was assessed by the presence or absence of pregnant females. At the same time, naive females, who did not participate in reproduction, assessed the urine of the successful males as more attractive, which was expressed in shorter Latency time of sniffs in the Olfactory test. Using a rapid headspace GC/MS analysis, we have found volatile organic compounds (VOCs) in male urine that correlated with female behavior. It turned out that these substances are derivatives of mouse pheromone 6-hydroxy-6-methyl-3-heptanone. The amplitude of peaks corresponding to this pheromone correlated with the testosterone level in blood and the weight of preputial glands. The amplitude of peaks increased in males after mating with whom the females turned out to be pregnant. It is important to note that body weight, weight of testes, weight of seminal vesicles, weight of preputial glands, and plasma testosterone level alone are not reliable indicators of male reproductive success. Thus, the content of the pheromone 6-hydroxy-6-methyl-3-heptanone in the urine of males can serve as a good predictor of the quality of the male as a sexual partner for female CD-1 mice.

[The P-Element Has Not Significant Effect on the Drosophila simulans Viability].

Cases of horizontal transfer of transposable elements (TEs) between species are known for the Drosophilidae family. In the middle of the last century, the case of horizontal transfer of the P-element from the Drosophila willistoni to the D. melanogaster was described. A novel P-element invasion into the D. simulans genome from D. melanogaster occurred approximately 10 years ago. Currently, the P-element has spread across all D. melanogaster population and 30% of D. simulans populations in Europe, Africa and America. In this paper, we investigated the presence of the P-element in D. simulans lines caught in different years in three Asian populations (Tashkent, Nalchik and Sakhalin Island). We also examined the physiological characteristics (cytotype, lifespan, fecundity and locomotor activity) of D. simulans lines with and without the P-element to determine the significance of this new mobile element in the genome. The P-element was found in lines isolated from nature after 2012. The number of P-element copies per genome (two-to-three dozen according to fluorescence in situ hybridization data) was greater than in the American and comparable to the African populations. There were signs of intraspecific hybrid dysgenesis for some pairs of lines. However, in general the presence of the P-element did not adversely affect the physiological characteristics. Either adaptation to the new TE occurs very quickly, or the rate of movement of the P-element is so insignificant that its appearance in the genome remains unnoticed.

Selective Cytotoxicity of Manganese Nanoparticles against Human Glioblastoma Cells.

Toxicity of different types of manganese nanoparticles against glioblastoma U-87MG and U-251 cells and normal human cells was studied using MTT test. The selectivity of the toxic effect of nanoparticles was evaluated as the ratio of 50% cytotoxic concentration (СС50) for human embryos fibroblasts (FECh-15) to their СС50 for tumor cells. Five of 6 samples of tested nanoparticles demonstrated selective toxic effect in vitro. Manganese oxide nanoparticles were characterized by maximum selectivity (СС50 6.9 nM and 2.1 nM for U-87MG and U-251 cells, respectively): selectivity index for glioblastoma U-87MG and U-251 cells was 29 and 95.2, respectively. Manganese oxide nanoparticles used for MRI detection of gliomas can be used for designing an oncolytic agent for the treatment of glial tumors in humans.

[Aerosol deposition in nasal passages of burrowing and ground rodents when breathing dust-laden air].

In subterranean rodents, which dig down the passages with frontal teeth, adaptation to the underground mode of life presumes forming of mechanisms that provide protection against inhaling dust particles of different size when digging. One of such mechanisms can be specific pattern of air flow organization in the nasal cavity. To test this assumption, comparative study of geometry and aerodynamics of nasal passages has been conducted with regard to typical representative of subterranean rodents, the mole vole, and a representative of ground rodents, the house mouse. Numerical modeling of air flows and deposition of micro- and nanoparticle aerosols indicates that sedimentation of model particles over the whole surface of nasal cavity is higher in mole vole than in house mouse. On the contrary, particles deposition on the surface of olfactory epithelium turns out to be substantially less in the burrowing rodent as compared to the ground one. Adaptive significance of the latter observation has been substantiated by experimental study on the uptake ofnanoparticles of hydrated manganese oxide MnO x (H2O)x and Mn ions from nasal cavity into brain. It has been shown with use of magnetic resonance tomography method that there is no difference between studied species with respect to intake of particles or ions by olfactory bulb when they are introduced intranasally. Meanwhile, when inhaling nanoparticle aerosol of MnCl2, deposition of Mn in mouse's olfactory bulbs surpasses markedly that in vole's bulbs. Thereby, the morphology of nasal passages as a factor determining the aerodynamics of upper respiratory tract ensures for burrowing rodents more efficient protection of both lungs and brain against inhaled aerosols than for ground ones.

[Conjugated variability of spontaneous activity and behavioral response to olfactory stimuli in the taiga tick (Ixodes persulcatus)].

According to -the automatic tracing of the movement of ticks in a Petri dish, motivational variability of the spontaneous activity and behavioral response of the taiga tick to olfactory stimuli was analyzed. In the studied sample, two groups of ticks that differ in the movement trajectory in the absence of stimulus were isolated, including ticks that mainly moved on the edge of the dish at maximum accessible height (group 1) and ticks that mainly moved at the bottom and wall of the dish (group 2). It was registered that ticks of group 1 (as opposed to ticks of group 2) demonstrated a pronounced behavioral response to olfactory stimuli (human synthetic pheromones and ammonia) and negative geotaxis. It was established that belonging to these groups depended On the time of day when the testing was performed and did not depend on the physiological age and infectious status.

[Magnetic resonance spectroscopy of metabolic changes in mice brain after 2-deoxy-D-glucose injection].

In vivo proton magnetic resonance spectroscopy (1H MRS) of ICR male mice was used to study the brain (hippocampus) metabolic response to the acute deficiency of the available energy or to the pro-inflammatory stimulus. Inhibition of glycolysis by means of an intraperitoneal injection with 2-deoxy-D-glucose (2DG) reduced the levels of gamma-aminobutiric acid (GABA), N-acetylaspartate (NAA) and choline compounds, and at the same time increased the levels of glutamate and glutamine. An opposite effect was found after injection with bacterial lipopolysaccharide (LPS)--a very common pro-inflammatory inducer. An increase in the amounts of GABA, NAA and choline compounds in the brain occurred three hours after the injection of LPS. Different metabolic responses to the energy deficiency and the pro-inflammatory stimuli can explain the contradictory results of the brain MRS studies under neurodegenerative pathology, which is accompanied by both mitochondrial dysfunction and inflammation. Prevalence of the excitatory metabolites such as glutamate and glutamine in 2DG treated mice is in good agreement with excitation observed during temporary reduction of the available energy under acute hypoxia or starvation. In turn, LPS, as an inducer of the sickness behavior, shifts brain metabolic pattern to prevalence of the inhibitory neurotransmitter GABA.

[Concentration of light hydrocarbons in exhaled air depending on the risk factors of metabolic disorder].

In this study we investigated the effect of risk factors of metabolic syndrome on the content of light hydrocarbons (C2-C3) in exhaled air. We used a gas chromatograph with a short multi-channel column. As a result, sex differences in concentrations of light hydrocarbons presented in exhaled air were found. In addition, such factors as smoking and diabetes mellitus type 2 in relatives reflect on the exhaled C2-C3 compounds only in women. But the overweight correlates with the exhaled acetone (C3) only in men. Thus, the fact that the metabolic changes caused by the presence of risk factors of metabolic syndrome lead to changes in gas composition of exhaled air and can be registered and used for early diagnosis has been ascertained.

[Changes in the energy status of Drosophila as a result of genetic mutation].

Conditional dominant lethals (CDL) represent a special class of genetic mutations observed in Drosophila. Mutation manifests as a dominant allele in one genotype, but lethality is not expressed in another genotype. CDL mutants exhibit a set of traits discriminating them from classic mutations. We observed unusually high mobility of flies and high sexual activity of males carrying these mutations. We used special tests for evaluation of energy metabolism of CDL mutants. Indirect calorimetry (CO2 excretion measurement) has been used for estimation of energy exchange in four mutant and two control fly lines. A Special device has been used for evaluation of locomotor activity of these fly lines. Energy exchange and locomotor activity in CDL mutants were significantly higher than in control lines. We conclude that some genetic mutations are capable of increasing energy dissipation in their carriers.

[Direct and chemosignal-mediated effects of immune activation on behavior, glucocorticoid level, and body temperature in male mice during social conflict].

Behavioral and physiological effects mediated by immune system activation response to the injection of sheep red blood cells (SRBC) have been established to be mediated by chemosignal modification to a considerable extent while conducting experiments on BALB/cLac and C57B1/6j male mice. Control mice of both strains have been characterized by the same increase in plasma coricosterone concentrations caused by territorial conflict between the control and SRBC-treated males; hence, the quality of bedding did not have an effect on hormonal response. The greatest level of plasma corticosterone in SRBC-treated mice was detected after dyadic tests of social conflict in the case of provided bedding from the control mice. The bedding odor also determined the agonistic behavior of more aggressive male BALB/cLac mice. Dyadic tests staged on bedding in SRBC-treated males led to a decrease in the amount of direct aggression in comparison to tests on bedding in control males; moreover, the number of aggressive demonstrations positively correlated with the increase in the rectal temperature, which might be considered a manifestation of the emotional reaction to territorial conflict.

[The energetic cost of social behavior in mice under activation of the nonspecific immunity].

Using originally designed low inertial open circuit respirometer, we studied influence of the bacterial endotoxin on the bioenergetic gain of male mice, which they showed after 15 min pair-wise test. Injection of lipopolysaccharide (LPS) provided increase of the post pair-wise test energy metabolism and increase of the relative energy cost of each agonistic act in dominant males. Significant correlation between energy response and number of agonistic acts in the pair-wise test was found only for LPS treated males. Spontaneous activity measured before social conflict and non-agonistic behavior during pair-wise test did not correlate with energy metabolism. Since all behavioral acts need energy and since the significant correlation between energy response and behavioral activity was found only for the agonistic behavior we assume these relationships being a result of synergetic influence on the energy metabolism of both the nonspecific immune response on LPS and neuroendocrine accompaniment of the intermale aggression.

[Antigen stimulation modifies social behavior and chemosignals in male laboratory mice].

The injection of outbred ICR strain male mice with SRBC affected their dominance ability in pair-wise test. In pair-wise tests done without previous presentation of the smell of a contestant, the SRBC-treated males submitted to control males. This effect occurred within 3 days after the injection. However, on the third day after treatment, under conditions of getting pre-test olfactory information about a contestant, the dominance of SRBC treated-males over the control animals was observed. Perception of the contestant smell is known to lead to emotional reaction and could be accompanied by an increase in energy metabolism. This increase was significant in both the control submissive and SRBC-treated dominate males. Thus, the modification of mice smell perception due to antigen injection can affect the pair-wise competition.