[Modeling the periodically-changing predictable response to mutagen exposure in CBA/LacY mice in a successive inbred generations]. / Modelirovanie periodicheski meniaiushchegosia prognoziruemogo otveta na mutagenye vozdeistviia u myshei CBA/LacY v riadu pokolenii inbridinga.

A hypothesis on the genetic determination of periodic fluctuations of the sensitivity to the mutagen thioTEPA in successive inbred generations of mice has been earlier put forward. This study was the initial stage of testing this hypothesis. The mouse strain CBA/LacY was divided into two substrains, which differed in the rate of generation change. As a result, two colonies of isogenic mice differing by 10-12 generations with respect to the inbred age were obtained. Both the rate and range of variations in the mutagen sensitivity (four generations per period of the cycle and 20-40% of cells with chromosome aberrations after the standard dose of 2.5 mg/kg of thioTEPA, respectively) in 19 generations of the "fast" substrain agreed with earlier data. The response of the "slow" substrain corresponded to the expected response of the "fast" substrain after the given number of generations. In the mice of generations F142 and F146 that lived simultaneously and differed in thioTEPA sensitivity, the effects of the carcinogen benzo[a]pyrene (BaP) were significantly different. The levels of these effects corresponded to the levels of the responses to thioTEPA. The data obtained agree with the hypothesis tested.

[Non-Mendelian inheritance of the Un(s) mutant gene in mice]. / Nemendelevskoe nasledovanie mutantnogo gena Un(s) u myshei.

The phenotypic expression of the mutation Uns (gene Pax-1) were studied in the progeny of heterozygous mice. In all crosses, the sex ratio close to 1:1 was observed in the progeny. However, among sons and daughters the segregation for the mutant character depended on the variant of the cross variant. When the Uns/+ mice were intercrossed, the ratio of mutant to normal females was 3:1, while the corresponding ratio among males was 0.9:1. Studying preimplantation development in vitro and postimplantation development in vivo revealed no significant mortality in embryos obtained by crossing heterozygous mice. Ultrastructural analysis revealed no distortions in synapsis and desynapsis of axial elements of the autosomal chromosomes in Uns/+ mice. The segregation found seems to result either from different fertilizing ability of normal sperm and sperm carrying the Uns mutation or, which is more probable, from the genetic imprinting of the gene Uns.

[Correlation of changes in bone marrow cell sensitivity to the clastogenic effect of thiotepa and fertility in CBA/LacY mice in successive inbred generations]. / Korreliatsiia kolebanii chuvstvitel'nosti kletok kostnogo mozga k klastogennomu éffektu tioTEF i plodovitosti u myshei linii CBA/LacY v riadu pokolenii inbridinga.

The causes of the significant increases in the sensitivity to of clastogenic effect of thio-TEPA in bone marrow cells of inbred CBA/LacY mice were studied. The increases were shown to be associated with decreased fertility. The fluctuations of fertility and the association of fertility and sensitivity with thio-TEPA were analyzed in foundation stocks (FSs) for 24 and 6 inbred generations, respectively. The stocks examined were obtained in the Laboratory of Experimental Biological Models and the Stolbovaya breeding facility. The correlation analysis revealed a significant association of fluctuations of the coefficient of fertility in two FSs (eta = 0.78 +/- 0.13) and a high negative correlation between fertility and mutagen sensitivity in inbred generations (r = -0.91 +/- 0.21). The comparison between the fluctuations of fertility for four generations revealed the same fluctuation period in CBA/LacY, DBA/2Y, and C57Bl/6JY mice. The detected phenomena were assumed to result from genetically determined regular fluctuations in genome functioning. This explained a number of observations and allowed several prognoses to be made.

[Athymic mice of the 101/HY strain with a new allele at the nude locus]. / Bestimusnye myshi linii 101/HY s novym allelem lokusa nude.

The spontaneous autosomal recessive mutation at locus nude (nuY) was discovered in 101/HY mice imperfect in respect to repair of induced chromosome damage and this is maintained in conventional conditions at RLEBM. Homozygous mutants have no hair and thymic differentiation. The new mutant form can be a valuable model for medical and biological experiments requiring T-cell immune deficiency.

[Histological study of oogenesis pathology in smoky mutant mice]. / Gistologicheskoe issledovanie patologii oogeneza myshei s mutatsiei smoky.

The various pathology of female mice reproductive system with the mutation smoky (smk) was observed. This recessive autosomal gene dilutes the black colour of hair to the light smoky. The cases with ovarian agenesis and dysgenesis of the mutants WR-smk/smk and B6-smk/smk without the germ cells or with the acute deficit was discovered. The oogenesis pathology of the mutants B6-smk/smk was revealed by the block of oocyte growth and their nucleus development in the growing nonatretic follicles leading to the female infertility. Endogene causes of the female hypogonadism and infertility associated with the mutation smoky are proposed.

[Morphofunctional characteristics of the reproductive system in female mice of the mutant strain B10-hr rhY]. / Morfofunktsional'naia kharakteristika reproduktivnoi sistemy samok mutantnoi linii myshei B10-hr rhY.

The long duration of the estrous cycle, the absence of the ovulated oocytes was observed in histomorphological studies of estrous cycles and ovaries in hr rhY-/hr rhY-mutants of B10-hr rhY mice strain. The absence of mutation division, ovulation and corpora lutea in ovaries was found in contrast to normal isogenic B10 females. The extragonadal cause of hairless mutant female infertility was shown. The effective method of mutant strain B10-hr rhY reproduction by using the transplantation of homozygous hairless female ovaries to isogenic recipients (+/+ or +/hr rhY) was proposed.

[Analysis of the damaging action of different doses of nicotine on the female germ cells of rat fetuses]. / Analiz povrezhdaiushchego deistviia razlichnykh doz nikotina na zhenskie polovye kletki plodov krys.

The conducted studies have shown the gametotropic dose-dependent nicotine effect revealed both at the light-optic and ultrastructural levels. The revealed disturbances in oocytes may be regarded as a nonspecific response of the sex cells which is observed mainly in damage of the membrane oocyte components and specific (for sex cells) structure, a synaptonemal complex. Disturbances in the somatic ovary cells manifest only with a high nicotine dose.

[Gametotoxic action of oxytetracycline on the early antenatal oogenesis of mice in in vivo and in vitro experiments]. / Gametotoksicheskoe deistvie oksitetratsiklina na rannii antenatal'nyi oogenez myshei v éksperimentakh in vivo i in vitro.

Examination of the histological sections of mouse ovaries in the antenatal period following oxytetracycline treatment during proliferation of oogonia has shown the adequacy of some indicators obtained in experiments in vivo and in vitro (the index of sexual cells, the mitotic index of oogonia, the index of pathological mitoses of oogonia). The gametotoxic action of the drug manifested itself in a significant increase of the pathological mitoses of oogonia.

[Histological evaluation of ovarian reproductive function in sexually mature mice after antenatal exposure to oxytetracycline]. / Gistologicheskaia otsenka reproduktivnoi funktsii iaichnikov polovozrelykh myshei posle antenatal'nogo vozdeistviia oksitetratsiklinom.

The action of oxytetracycline, an inhibitor of protein synthesis, on the antenatal mouse ovaries during proliferation of oogonia and their transition to the preleptotene stage leads to a decrease in the oocyte and follicle pools and to that in the number of ovulated oocytes in the mature offspring.

[Antenatal oogenesis in mice and its experimental modification]. / Antenatal'nyi oogenez u myshei i ego éksperimental'naia modifikatsiia.

The repeated (twice) intramuscular injection of oxytetracycline (5 mg per mouse) within 12 and 13 days after mating induced the increase of a relative number of pathological and atretic mitoses in the oogonia and, later on, the decrease of a relative number of diplotenes and early dictyotenes. The same dose injected within 16 and 17 days induced a higher degeneration of oocytes in pachytene and diplotene and inhibited the initiation of folliculogenesis.

[Apical growth of the bud in Hydra]. / Verkhushechnyi prirost pochki gidry

The experiments with markers combined with the vital and histological methods have shown that there is a zone of apical accretion in the bud of Hydra attenuatu. During one of the phases of periodic cell movement, the mesoglea breaks through in the center of apex and the endodermal cells insert in the ectoderm.