Ludmila A. Gerlinskaya

Behaviour, chemosignals and endocrine functions in male mice infected with tick-borne encephalitis virus

Odour attractiveness, social behaviour and endocrine status of male mice (outbred ICR strain) were examined 6-7 days after inoculation with subclinical dose of tick-borne encephalitis virus (TBE). According to RT-PCR control of efficiency of infection, males injected with TBE were divided on the two subgroups: TBE+ (males with viral RNA) and TBE- (males without viral RNA). Susceptible males (TBE+ subgroup) showed the higher level of plasma testosterone in comparison with both control and nonsusceptible (TBE- subgroup) males. TBE+ males had also more odour attraction for oestrus females and more aggressiveness in social conflict. Higher sexual attractiveness and aggressiveness of the infected host benefit the pathogens distribution in the host population.

[Sexual transmission of tick-borne encephalitis virus in laboratory mice].

Mating of males infected with tick-borne encephalitis virus (strain Sofyin) with intact females results in a marked decrease in the weight of embryos and an almost threefodl increase in embryonal mortality. Viral RNA was identified by the polymerase chain reaction in embryonal tissues of 2 out of 11 litters. In one case the infection of the progeny was confirmed by biological test.

Comparison of behavioral and biochemical deficits in rats with hereditary defined or d-galactose-induced accelerated senescence: Evaluating the protective effects of diosgenin

One of the important factors in aging is oxidative stress and aging-related disturbances are believed be ameliorated by antioxidants. Diosgenin is a bio-active ingredient of dioscorea that is widely used in Chinese medicine, shows anti-oxidant activity and improves some aging-related deficits in senescent and menopausal animals. We compared alterations in behavior, biochemical parameters (plasma levels of the uric acid, creatinine, calcium, phosphate, total cholesterol, low-density lipoprotein cholesterol and triglycerides, and the plasma activity of aminotransferases AST and ALT), and sperm motility in two models of accelerated senescence (d-galactose-induced (150 mg/kg/day, i.p., 57 days) aging in Wistar rats vs. genetically defined in OXYS rats) and examined the protective effects of diosgenin (10 or 50mg/kg/day, p.o., 57 days). Both models had augmented levels of ALT activity indicating hepatopathology. Compared to d-galactose-treated animals, OXYS rats demonstrated profound biochemical alterations (hypocalcemia, hypophosphatemia, and hypocholesterolemia) and behavioral deficits (impaired object recognition, decreased sexual motivation and locomotor activity, retarded learning) that confirmed the difference in the mechanisms of accelerated senescence in these models. We first showed diminished sperm motility in males of both models of accelerated senescence studied. Chronic diosgenin treatment failed to improve biochemical and behavioral disturbances and had some undesirable side effects on body weight and working memory in OXYS rats. However, diosgenin restored moderately decreased sperm motility in d-galactose-treated Wistar males and might be recommended for treatment of mild age-related reproductive dysfunctions.

Female scent mobilizes leukocytes to airways in BALB/c male mice.

The scent of receptive females as a signal to reproduction stimulates male mice to olfactory search of a potential breeding partner. This searching behavior is coupled with infection risk due to bacterial contamination of the fecal and urine scent marks. We hypothesized that sniffing of female soiled bedding induced the migration of immuno-competent cells into airways as a possible adaptation to breeding-related infection. Using bronchoalveolar lavage in a study on mice, we found the number of leukocytes to be significantly higher in male mice that were provided new portions of soiled bedding daily from female cages, in comparison with male mice that were kept in isolation from female scent. The number of leukocytes in blood was equal in both groups. However, monocytes were fewer in number in male mice exposed to female scent than in male mice isolated from female mice. Scent-induced migration of leukocytes was accompanied by typical behavioral (increased sniffing activity and aggressiveness) and morphological (increase preputial glands and seminal vesicles) responses to olfactory sexual stimulus.

IL-1β-independent activation of lung immunity in male mice by female odor.

In previous studies, we showed that long-term perception of female odor increases flu virus resistance in male mice. To expand on this finding, we examined the ability of female chemical cues to rapidly induce leukocyte mobilization into male lung tissue as a critical condition of signal-derived respiratory infection risk reduction, which is usually associated with sniffing scent marks. Here, we compared the immune and endocrine effects of female chemical cues and lipopolysaccharide (LPS) as common triggers of innate immunity. The number of leukocytes in the lung tissue, concentrations of IL-1β in lung and hypothalamus, and plasma corticosterone and testosterone levels were assessed in ICR male mice 2h after the intranasal application of female urine, LPS or urine and LPS. Both stimuli induced leukocyte mobilization but, in contrast to LPS, female urine alone did not stimulate increased IL-1β levels in lung and hypothalamus. Plasma corticosterone increased and plasma testosterone decreased in response to LPS, whereas the concentrations of these hormones did not change in response to female chemical cues. Thus, the present study gives additional evidence for an anticipatory adaptation of male mice to potential breeding risks. Appreciable mobilization of leukocytes to the lungs requires less than 2h and develops through an IL-1β-independent pathway.

Odor as an element of subjective assessment of attractiveness of young males and females

In 46 male and 19 female students who were both donors and recipients of odor samples, we studied effects of the menstrual cycle phase, reproductive health, sexual motivation, and sexual experience on subjective assessment of intensity and attractiveness of the sweat odor. The sweat samples were collected by the 60-min long exposure of a filter paper in the armpit. Then the male and female samples were reciprocally assessed olfactorily with respect to their intensity, unattractiveness/attractiveness, and association with male or female. It has been established that the cycle phase affects statistically significantly the coincidence of subjective assessments by the unpleasant/pleasant scale, which different recipients were giving to the same odor samples. Their coincidence in the non-receptive state is replaced by the non-coincidence at the receptive cycle phase, which indicates an increase in the contribution of the recipient’s individual properties to the variability of odor assessments. In girls in the non-receptive state there is noted the reverse correlation between the strength and attractiveness of the male odor. In the receptive state, they become tolerant to intensive male odors. At non-regular menstrual cycles, the female odor is assessed by young males as less pleasant. At the same time, the girls themselves with the cycle disturbances assess higher the male odor samples as compared with the girls who had regular cycles. The first sexual experience decreases the subjective scores given by girls to the male odor samples. The young males, on the contrary, increase assessments of the female odor after acquiring the sexual experiment. Coefficients of correlation of the mutual assessments of odor attractiveness of young males and females are progressively rising with increase of biological and social significance of the search for optimal partner. Thus, effect of psychophysiological and social factors on assessments of attractiveness of odor samples agrees well with requirements, to which the reproductively significant non-verbal signal should fit.

Antigen-induced changes in odor attractiveness and reproductive output in male mice

Modulation of social signals by antigen-induced immunoenhancement is a significant component of behavioral and reproductive adaptations of a host population to parasitic pressure. To investigate this concept, we studied odor attractiveness and reproductive output of ICR male mice treated with keyhole limpet hemocyanin (KLH) as an antigenic stimulus. We collected urine samples for olfactory preference tests (control vs. KLH administration) on different days following treatment. We found that the differences in odor attractiveness between control and immunized males, which were observed on the 3rd day, disappeared soon afterwards. Odor attractiveness of male mice positively correlated with their immunoresponsiveness, which was assessed by the sum of anti-KLH IgG1 and anti-KLH IgG2a titers. According to the hypothesis of terminal investment, antigen-treated males had higher reproductive output in comparison with control males and produced more progeny as a result.

Modulation of embryonic development due to mating with immunised males

The modification of pre- and postnatal development conferred by immunogenic stimulation of mothers provides a population-level adaptation mechanism for non-genetic transfer of maternal experiences to progeny. However little is known about the transmission of paternal immune experiences to offspring. Here, we show that immune priming of males 3-9 days before mating affects the growth and humoral environment of developing embryos of outbred (ICR) and inbred (C57BL and BALB/c) mice. Antigenic stimulation of fathers caused a significant increase in embryonic bodyweight as measured on Day 16 of pregnancy and altered other gestation parameters, such as feto-placental ratio. Pregnant females mated with immunised males were also characterised by changes in humoral conditions as shown by measurements of blood and amniotic progesterone, testosterone and granulocyte-macrophage colony-stimulating factor (GM-CSF) cytokine concentrations. These results emphasise the role of paternal effects of immune priming on the in utero environment and fetal growth.

Nanoparticles Associate with Intrinsically Disordered RNA-Binding Proteins

Nanoparticles are capable of penetrating cells, but little is known about the way they interact with intracellular proteome. Here we show that inorganic nanoparticles associate with low-complexity, intrinsically disordered proteins from HeLa cytosolic protein extracts in nondenaturing in vitro nanoparticle pull-down assays. Intrinsic protein disorder associates with structural mobility, suggesting that side-chain flexibility plays an important role in the driving of a protein to nanoparticle absorption. Disordered protein domains are often found in a diverse group of RNA-binding proteins. Consequently, the nanoparticle-associated proteomes were enriched in subunits of RNA-processing protein complexes. In turn, this indicates that within a cell, nanoparticles might interfere with protein synthesis triggering a range of cellular responses.