[Chemosignals from isolated females have antimutagenic effect in dividing the cells of bone marrow from male mice of the CBA line].

A level of X-ray induced mitotic disturbances in the cells of the bone marrow of male mice was studied under the modifying influence ofchemosignals from isolated adult female mice of the CBA line. It has been shown that the frequency of chromosomal aberrations in irradiated (4 Gr) males after exposing them for 24 hours on bedding soiled with female chemosignals is lower than in irradiated males in cages with clean bedding. The mechanisms and importance of the antimutagenic effect of female house mouse chemosignals are discussed.

[Balance hypothesis of action of socially significant volatile chemosignals on reactivity of chromosome machinery of the bone marrow dividing cells in the house mouse Mus domesticus L].

Volatile chemosignals released by female CBA laboratory mice have been shown to produce action of different direction, depending on conditions of performance of experiment, on chromosome machinery of bone marrow cells in syngenic adult males. Thus, chemosignals secreted into environment by isolated adult females decrease frequency of mitotic disturbances in bone marrow dividing cells in male recipients as compared with spontaneous level in control animals. At the same time, 2,5-dimethylpyrazine - pheronome released only by high density caged females - increases frequency of mitotic disturbances. Preliminary 24-h-long action of chemosignals of isolated females decreases effect of the subsequent action of 2,5-dimethylpyrazine, although the level of disturbances exceeds that in control animals. The simultaneous action of used chemosignals neutralizes completely the 2,5-dimethylpyrazine action, the frequency of mitotic disturbances being not different from that after chemosignals of isolated females. The hypothesis is put forward about dependence of the revealed cytogenetic effects in male recipients on zoosocial conditions of maintenance of female donors of chemocommunication signals.

[Action of two pyrazine-containing chemosignals on cells of bone marrow and testes in male house mouse Mus musculus L].

Evolutionary conservative chemosignal 2,5-dimethylpyrazin that is pheromone in female mice has been shown to increase frequency of mitotic aberrations analyzed with aid of metaphasic and ana-telophasic analysis in bone marrow cells. Replacement of one of methyl radicals in the pheromone molecule by the carboxyl radical reveals specificity of action of the used derivative: the frequency of disturbances revealed only by the ana-telophasic analysis increases, whereas by the metaphasic analysis, no induction of disturbance is detected. In the sperm head abnormality test there is shown a rise of the anomalies by both compounds. Possible mechanisms of specific action of the tested substances on stability of genetic apparatus of the bone marrow dividing cells in the house mouse are discussed.

[The role of metabolic activation of promutagens in the genome destabilization under pheromonal stress in the house mouse (Mus musculus)].

The hypothesis on a relationship between the high frequency of mitotic disturbances in bone marrow cells and the change in the activity of the S9 liver fraction containing promutagen-activating enzymes under olfactory stress in the house mouse Mus musculus has been tested. For this purpose, the effect of the pheromone 2,5-dimethylpyrazine on the frequency of mitotic disturbances in mouse bone marrow cells has been measured by the anaphase-telophase assay. The Ames test using Salmonella typhimurium has been employed to compare the capacities of the S9 liver fractions from stressed and intact mice for activating the promutagen 2-aminofluorene. It has been demonstrated that the increased frequency of mitotic disturbances in bone marrow cells induced by the pheromonal stressor in male house mice is accompanied by an increased promutagen-activating capacity of the S9 liver fraction. The model system used in the study allowed the genetic consequences of the exposure to the olfactory stressor to be estimated and the possible mechanisms of genome destabilization to be assumed.

[Effects of "pheromone-like" pyrazine-containing substances on stability of genetic apparatus in bone marrow cells of the male house mouse (Mus musculus L.)].

There was studied effect of female house mouse pheromone 2,5-dimethylpyrazine and other pyrazine-containing substances on the genetic apparatus stability of dividing bone marrow cells of male mice of the strain CBA. Differences in action of the used chemosignals are revealed. Role of the method of action on induction of analyzed mitotic aberrations is shown. Spectrum of the aberrations is analyzed. Dependence of cytogenetic activity of the used substances on their structural peculiarities and significance of the revealed effects are discussed.

[Chromosomal abnormalities and spleenocyte production in laboratory mouse males after exposure to stress chemosignals].

Activity of antibody producing spleenocytes and chromosome stability in bone marrow cells from laboratory mouse males of CBA strain after exposure to different chemosignals excreted by stressed or irradiated syngeneic donors was studied. It has been shown that the exposure of the recipient males to volatiles from donor males (stressed by swimming) decreases quantity of antibody-producing cells in 1, 3 and 10 days after the treatment. The same exposure increased the chromosome aberrations level in dividing bone marrow cells from CBA recipients in 1 day after the treatment. Similar changes were observed in 24 h after exposure to volatiles of irradiated donors or to synthetic mouse pheromone, 2,5-dimethylpyrazine. Possible mechanisms of chemosignals effect on the immune system are discussed.

[Effect of the estrous cycle stage on sensitivity to pheromone 2,5-dimethylpyrazine in the house mouse Mus musculus].

Frequency of cytogenetic disturbances was estimated in mitotically dividing bone marrow cells of CBA strain female mice after the 24-h long action of pheromone 2,5-dimethylpyrazine (2,5-DMP). The stage of the estrous cycle of each animal was taken into account at the moment of the end of the pheromone action. The analysis was performed using the anatelophase method that allows evaluating frequencies of various types of disturbances--bridges, fragments, delayed chromosomes. The spontaneous level of the mitotic disturbances revealed by the anatelophase method in animals of the control group amounts to 5.4 %. Action of pheromone 2,5-dimethylpyrasine induced the mitosis disturbances detected in the dividing bone marrow cells at the anaphase-telophase stage in the females at the di- + postestrus stage. The corresponding frequency of disturbances after the pheromone action was equal to 9.2%. In the female in estrus, the mitotic disturbance level amounted 6.7%, which did not differ statistically significantly from control. It is suggested that differences in the female mouse hormonal state at different estrous cycle stages affect sensitivity to olfactory signals. Mechanisms of the revealed effect and significance of the differences in sensitivity to pheromone for reproductive processes are discussed.

[Induction of meiotic disturbances in spermatocytes I by pheromones as an inhibiting mechanism of male reproductive function in house mice].

The influence of pheromons on reproduction and other important physiological characteristics has been reported for many mammalian species. However, mechanisms of this action at the level of target cells still remain unclear. A study was made of the influence of non-identified pheromones from adult males and a female pheromone 2,5-dimethylpyrazine on germ cells of CBA inbred strain mice. Cytogenetic analysis shows a significant increase in such meiotic disturbances as multivalent associations and autsomal univalents 24 h after exposure to pheromonal cues. Results of in situ hybridization show that the level of c-fos and c-jun expression is significantly higher 3.5 h after exposure to pheromones of adult males. It is likely that destabilization of chromosomal apparatus in dividing meiotic cells forms the basis of some reproductive effects of murine pheromones. Possible mechanisms of pheromone influence on reproduction are discussed.

[The female pheromone 2,5-dimethylpyrazine induces sperm head abnormalities in male CBA mice]. / Induktsiia anomalii golovok spermiev u samtsov myshei linii CBA feromonom samok myshei 2,5-dimetilpirazinom.

The effect of the house mouse female pheromone 2,5-dimethylpyrazine (2,5-DMP) on sperm differentiation in male CBA mice has been studied. For this purpose, mature males were treated with a 0.01% aqueous solution of the pheromone for six days. Control mice were similarly treated with physiologic saline. The mice were sacrificed 23 days after the treatment, and material for the analysis of sperm-head abnormalities was sampled from the caudal portion of the epididymis. Analysis of the frequency of abnormal sperms has demonstrated that the pheromonal treatment significantly increases the frequencies of various sperm-head abnormalities. Apparently, this results from disturbances in sex-cell differentiation germline cells caused by the induction of genetic damage at stages immediately preceding meiosis, as well as during the first and second meiotic divisions. The relationship between the effect of 2,5-DMP and the decrease in the fertility of male CBA mice that was earlier observed after a similar treatment is discussed.

[Localization of various DNA sequences on the mitotic chromosomes of the chicken]. / Lokalizatsiia nekotorykh posledovatel'nostei DNK na mitoticheskikh khromosomakh kuritsy.

The chromosomal localization of the chicken transferrin receptor gene, as well as sequences that were homologous to the viral oncogene v-fos and the human gene families ZFY and SRY were determined by the method of nonisotopic DNA-DNA in situ hybridization. A correspondence was revealed between the Comptonian linkage group 10 and chromosome 1. A common origin of avian chromosome Z and mammalian chromosome Y is hypothesized.

[The detection of a cluster of beta-globin genes in the long arm of chromosome 2 in the domestic hen by using DNA-DNA in situ hybridization]. / Vyiavlenie klastera beta-globinovykh genov v dlinnom pleche khromosomy 2 domashnei kuritsy s pomoshch'iu gibridizatsii DNK--DNK in sit u.

Using isotopic and nonisotopic methods of in situ hybridization, the localization the beta-like globin gene cluster was established. Molecular hybridization of DNA probes containing embryonic epsilon-globin and adult beta-globin genes revealed the localization of the cluster of the long arm on chromosome 2 (2q).

[Radiosensitivity of somatic cells and imaginal disks of male and female Drosohila]. / Radiochuvstvitel'nost' somaticheskikh kletok i imaginal'nykh diskov samok i samtsov drozofily.

Primary chromosome damages as well as the frequency of spontaneous and X-rays induced chromosome aberrations in Drosophila melanogaster males and females are studied. It is found using cytofluorimetric method that primary chromosome damages in ganglia cells of females and males are the same. In these cells as well as in cells of imaginal discs the frequency of induced chromosome aberrations, except gaps, is considerably higher for females. Ganglia cells of females and males of Drosophila are found not to differ from each other in their proliferation activity. The frequency of morphoses for both sexes is also the same. The assumption is made concerning the role of the non-identical repair in the increased mutability of female somatic cells, which is more intensive in this sex, as well as concerning more intensive identical repair in imaginal discs of females.