Enhancement of the Clastogenic Effects of Topotecan In Vivo by Tyrosyl-DNA Phosphodiesterase 1 Inhibitors.

Topotecan administered intraperitoneally at single doses of 0.25, 0.5, and 1 mg/kg induced chromosomal aberrations in bone marrow cells of F1(CBA×C57BL/6) hybrid mice in a dose-dependent manner. A tyrosyl-DNA phosphodiesterase 1 (TDP1) inhibitor, an usnic acid derivative OL9-116 was inactive in a dose range of 20-240 mg/kg, but enhanced the cytogenetic effect of topotecan (0.25 mg/kg) at a dose of 40 mg/kg (per os). The TDP1 inhibitor, a coumarin derivative TX-2552 (at doses of 20, 40, 80, and 160 mg/kg per os), increased the level of aberrant metaphases induced by topotecan (0.25 mg/kg) by 2.1-2.6 times, but was inactive at a dose of 10 mg/kg. The results indicate that TDP1 inhibitors enhance the clastogenic activity of topotecan in mouse bone marrow cells in vivo and are characterized by different dose profiles of the co-mutagenic effects.

Potato Solanum tuberosum L. Phytoene Synthase Genes (StPSY1, StPSY2, and StPSY3) Are Involved in the Plant Response to Cold Stress.

The structure and phylogeny of the Solanum tuberosum L. phytoene synthase genes StPSY1, StPSY2, and StPSY3 were characterized. Their expression was studied in potato seedlings exposed to cold stress in the dark phase of the diurnal cycle to simulate night cooling. All of the three genes were activated as the temperature decreased, and the greatest response was observed for StPSY1. StPSY3 was for the first time shown to respond to cold stress and photoperiod. A search for cis-regulatory elements was carried out in the promoter regions and 5'-UTRs of the StPSY genes, and the regulation of all three genes proved associated with the response to light. A high level of cold-induced activation of StPSY1 was tentatively attributed to the presence of cis elements associated with sensitivity to cold and ABA.

Damage to Nuclear and Mitochondrial DNA in Different Organs in Streptozotocin-Induced Diabetes Models in BALB/c Mice.

Male BALB/c mice with streptozotocin-induced diabetes mellitus were used to study nuclear DNA (nDNA) and mitochondrial DNA (mtDNA) damage using comet DNA assay and real-time PCR, respectively. In animals receiving single injection of streptozotocin in a dose of 200 mg/kg, severe hyperglycemia was observed on days 10 and 21 of the experiment, while after 5-fold administration of streptozotocin in a dose of 40 mg/kg, it developed on days 14 and 28. DNA damage and the level of atypical DNA comets in the liver increased both on days 10 and 21 after single administration of streptozotocin, and on days 14 and 28 after repeated administrations. The level of atypical DNA comets on day 21 after a single administration of streptozotocin increased in the kidneys, but not in the brain, testes, and pancreas. Real-time PCR revealed mtDNA damage in the liver, kidney, and pancreatic cells of mice with streptozotocin-induced diabetes. Thus, these animal models were found to reproduce pathognomic signs of diabetes, hyperglycemia, and nDNA damage; mtDNA damage was also detected.

Induced Aneugenic Effects in Mouse Oocytes In Vivo.

Aneugenic effects of the chemicals with antitumor activity were studied in mouse oocytes in vivo by cytogenetic analysis. In control mice, no oocytes with numerical chromosome aberrations were found. Colchicine (0.2-4 mg/kg), paclitaxel (2.5-7.5 mg/kg), and etoposide (10-60 mg/kg) produced a significant dose-dependent aneugenic effects (induction of up to 25% aneuploid oocytes) and increased the yield of oocytes arrested in the meiotic MI stage and with premature separation of sister chromatid. Paclitaxel induced up to 20% polyploid chromosomes. Doxorubicin (2.5 mg/kg), melphalan (10 mg/kg), and cisplatin (5-10 mg/kg) exhibited weak aneugenic activity (induction of up to 5% aneuploid oocytes). Cyclophosphamide (10-80 mg/kg) had minor effect on the studied parameters. Methotrexate (25-200 mg/kg) exhibited no aneugenic activity, but significantly increased the level of polyploid cells. The observed aneugenic effects included hypo- and hyperploidy in various proportions or hypoploidy, but no solely hyperhaploidy.

[Influence of Acetylcysteine on Cytogenetic Effects of Etoposide in Mouse Oocytes].

The influence of N-acetylcysteine (ACC) on the cytogenetic effects of etoposide in F1 CBA x C57BL/6 mice was studied. Etoposide introduced intraperitoneally in doses of 10, 20, 40, and 60 mg/kg has a dose-dependent clastogenic activity and has an aneugenic effect with the induction of mainly hypohaploid oocytes. ACC significantly decreases the aneugenic and clastogenic activity of etoposide (20 mg/kg) in oocytes of 6-, 9-, and 12-week-old mice during triple introduction at a dose 200 mg/kg per os. The most pronounced anticlastogenic ACC activity (an 80% decrease) was registered in 9-week-old females; a 100% decrease in aneugenesis was detected in 6-week-old female mice.

[EVALUATION OF THE CYTOGENETIC AND MUTAGEN-MODIFYING ACTIVITY OF CAFFEINE IN MOUSE BONE MARROW CELLS].

The cytogenetic and mutagen-modifying activity of caffeine was studied with the method of chromosomal aberrations in bone marrow cells of mice hybrids F1 CBAxC57BL/6. Caffeine per se was administered intragastrically or intraperitoneally, and in combination with mutagens--intragastrically. Mutagens injected intraperitoneally. Caffeine at doses of 10 and 100 mg/kg (single dose) and 10 mg/kg (five days) in parenteral administration and oral introduction failed to possess cytogenetic activity. In combination with mutagens caffeine (1, 10 and 100 mg/kg) had no effect on the cytogenetic activity of dioxydine (200 mg/kg/intraperitoneally) for a single coadministration, five-day pre or five-day coadministration. In combination with other mutagens under the same processing conditions caffeine at doses of 10 and 100 mg/kg significantly increased cytogenetic effects of cyclophosphamide (20 mg/kg) in the pretreatment of the animals and at the dose of 100 mg/kg significantly attenuated the cytogenetic effect of cisplatin (5 mg/kg) in single and repeated co-administration. Thus we have shown the absence of caffeine cytogenetic activity in vivo and showed the multidirectional effect of caffeine in doses far exceeding its daily consumption, to the manifestation ofcytogenetic effects of certain chemical mutagens in some modes of processing animals.

Genome variability of domestic tomato varieties: data from AFLP analysis.

Tomato Solanum lycopersicum L. is one of the main vegetable crops, accessions and cultivars of which are characterized by a low level of genomic polymorphism. Introgressive tomato breeding uses related wild Solanum species to improve cultivars for stress tolerance and fruit quality traits. The aim of this work was to evaluate the genome variability of 59 cultivars and perspective breeding lines of S. lycopersicum and 11 wild tomato species using the AFLP method. According to the AFLP analysis, four combinations of primers E32/M59, E32/M57, E38/M57, and E41/M59, which had the highest PIC (polymorphism information content) values, were selected. In the process of genotyping a collection of 59 cultivars/lines of S. lycopersicum and 11 wild tomato accessions, the selected primers revealed 391 fragments ranging in size from 80 to 450 bp, of which 114 fragments turned out to be polymorphic and 25 were unique. Analysis of the amplif ication spectra placed wild tomato accessions into separate clades. Sister clades included cultivars of FSCV breeding resistant to drought and/or cold and, in part, to late blight, Alternaria, Septoria, tobacco mosaic virus and blossom end rot, as well as tomato accessions not characterized according to these traits, which suggests that they have resistance to stress factors. In accessions of distant clades, there was clustering on the basis of resistance to Verticillium, cladosporiosis, Fusarium, tobacco mosaic virus, gray rot, and blossom end rot. The combination of ac cessions according to their origin from the originating organization was shown. The primer combinations E32/M59, E32/M57, E38/M57 and E41/M59 were shown to be perspective for genotyping tomato cultivars to select donors of resistance to various stress factors. The clade-specif ic fragments identif ied in this work can become the basis for the development of AFLP markers for traits of resistance to stress factors.

Dependence of the content of starch and reducing sugars on the level of expression of the genes of ß-amylases StBAM1 and StBAM9 and the amylase inhibitor StAI during long-term low-temperature storage of potato tubers.

Solanum tuberosum L. is the most important non-grain starch crop with a potential yield of 38-48 t/ha and a starch content of 13.2-18.7 %. Potato tubers are stored at a low temperature (2-4 °C) in a state of physiological dormancy. A disadvantage of this type of storage is the degradation of starch and the accumulation of reducing sugars (cold-induced sweetening), including due to an increase in the activity of ß-amylases that hydrolyze starch to maltose. In this study, a comparative analysis of the ß-amylase (StBAM1, StBAM9) and amylase inhibitor (StAI ) gene expression, as well as starch and reducing sugar content in tubers during long-term low-temperature storage (September, February, April) was performed using potato cultivars Nadezhda, Barin, Krasavchik, Severnoe siyanie and Utro. The ß-amylase genes, StBAM9 and one of the two StBAM1 homologs (with the highest degree of homology with AtBAM1), were selected based on phylogenetic analysis data. Evaluation of the expression of these genes and the amylase inhibitor gene showed a tendency to decrease in transcription for all analyzed cultivars. The starch content also significantly decreased during tuber storage. The amount of reducing sugars increased in the September-April period, while in February-April, their content did not change (Krasavchik), decreased (Barin, Severnoe siyanie) or continued to grow (Utro, Nadezhda). It can be assumed that the gene activity of StBAM1 and StBAM9 correlates with the amount of starch (positively) and monosaccharides (negatively). The level of StAI expression, in turn, may be directly dependent on the level of StBAM1 expression. At the same time, there is no relationship between the degree of cultivar predisposition to cold-induced sweetening and the expression profile of the StBAM1, StBAM9, and StAI genes.

[Preclinical safety investigation of GB-115 dipeptide].

Preclinical safety investigations of newly synthesized dipeptide compound GB-115 (amide N-phenylhexanoyl-glycyl-L-tryptophan), an antagonist of cholecystokinin receptors, were performed. No animals were lost after GB-115 acute oral administration at a maximum dose of 6000 mg/kg in mice and at 3500 mg/kg in rats. GB-115 administered per os during 6 months in rabbits and rats (both males and females) at the doses of 0.1 and 10 mg/kg induced no irreversible pathological changes in organs and systems studied. The tested dipeptide exhibited no allergenic, immunotoxic and mutagenic activity, and did not affect generative function and the antenatal and postnatal development of progeny. GB-115 at a dose of 10 mg/kg produced suppression of the inflammatory reaction to concanavalin A.

[Corpuscular mutagenesis and its prevention]. / Korpuskuliarnyi mutagenez i ego profilaktika.

The carcinogenic and mutagenic activity of dust containing chrysotile-asbestos and zeolites, as well as the role of active oxygen species in their cytotoxic and mutagenic actions are discussed. Superoxide dismutase (50 mg/ml) was demonstrated to prevent the mutagenic effects of chrysotile-asbestos and latex, catalase (20 mg/ml) to prevent the same of zeolites in experiments on cultured human whole blood. The intraperitoneal administration of dusts of chrysotile-asbestos and zeolites in a dose of 50 mg/kg to C57B1/6 mice was found to elevate the count of cells with chromosomal aberrations in the peritoneal liquid and bone marrow cells of mice, which was dependent on dust exposure time. It was revealed that ascorbic acid, rutin, chemically modified flavonoid of Scutellaria Baicalensis Georgy, drugs such as bemitil and thomersol in the broad range of concentrations (10(-7)-10(-3) M) decreased or completely reduced the clustogenic action of zeolites and chrysotile-asbestos on cultured human whole blood. The ability of bemitil (1.8-19 mg/kg) rather than the others to prevent the mutagenic effect of chrysotile-asbestos was confirmed by the method of recording chromosomal aberrations in the cells of peritoneal liquid and bone marrow in mice. The findings suggest that the mutagenic effects of the corpuscular xenobiotics under study are mediated by active oxygen species and that the use of the models in vitro and in vivo is adequate for investigations into corpuscular mutagenesis. Based on their own data and literature data, the authors have defined possible lines of further research of corpuscular mutagenesis.

[The antimutagenic activity of aspartame]. / Antimutagennaia aktivnost' aspartama.

The method of chromosome aberration count in the bone marrow cells of C57B1/6 mice was used to study the influence of aspartame on the cytogenetic effects of dioxydin and cyclophosphan. Aspartame (0.4-40 mg/kg) was found to possess antimutagenic properties in relation to the listed mutagens. The discovered antimutagenic activity of aspartame was manifested more when it was injected for 5 days before the administration of a mutagen, whereas in joint administration of aspartame with the mutagens, the substitute for sugar did not change the clastogenic effect of dioxydin and cyclophosphan.

[Effect of plant melanin pigment on the clastogenic effects of chemical mutagens in mice]. / Vliianie rastitel'nogo melaninovogo pigmenta na klastogennye éffekty khimicheskikh mutagenov u myshei.

The chromosome aberration assay in the bone marrow cells of C57BL/6 mice showed that melanin pigment (MP) in a dose range from 0.01 to 10 mg/kg does not influence the clastogenic effect of dioxidine (200 mg/kg, i.p.), while reducing the clastogenic effect of cyclophosphamide (20 mg/kg, i.p.) by a factor of 1.5-4 in various treatment regimes depending on the mutagen injection time.

[Preclinical study of noopept toxicity]. / Doklinicheskoe izuchenie toksichnisti noopepta.

Within the framework of a preclinical investigation, the new nootrope drug noopept (N-phenyl-acetyl-L-propyl-glycine ethylate) was tested for chronic toxicity upon peroral administration in a dose of 10 or 100 mg/kg over 6 months in both male and female rabbits. The results of observations showed that noopept administered in this dose range induced no irreversible pathologic changes in the organs and systems studied and exhibited no allergenic, immunotoxic, and mutagen activity. The drug affected neither the generative function nor the antenatal or postnatal progeny development. Noopept produced a dose-dependent suppression of inflammation reaction to concanavalin A and stimulated the cellular and humoral immune response in mice.

[Analysis of cytogenetic activity of food dyes]. / Analiz tsitogeneticheskoi aktivnosti pishchevykh krasitele'i.

The cytogenetic activity of food dyes was examined in the experiments on male C57B1/6 mice which were orally given during 5 days the following daily doses: Tartrasine (E102), 0.5 and 5.0 mg/kg; Indigo carmine (E132), 1.4 and 14 mg/kg; Canset yellow (E110), 0.17 and 1.7 mg/kg; Cochenillerot A (E124), 0.63 and 6.3mg/kg; Azorubin (E122), 1 and 10 mg/kg and Patentblau V (E131), 0.08 and 0.8 mg/kg. Five hundred metaphase slides each were analyzed in the control and experimental test series. The findings may conclude that the dyes tested within the above dose ranges do not induce any increase in the level of cells with chromosomal damages in the inbred animals.

[Clastogenic activity of dietary sugar substitutes]. / Issledovanie klastogennoi aktivnosti pishchevykh sakharozamenitelei.

The present paper describes the possible clastogenic activity of the following synthetic sugar substitutes, such as cyclamate in daily doses of 11 and 110 mg/kg, saccharin, 5 and 50 mg/kg, acesulfam, 15 and 150 mg/kg, sucralose, 15 and 150 mg/kg, aspartame, 40 and 400 mg/kg, orally given to C57Bl/6 mice during 5 days. No clastogenic activity was found in the compounds tested.

In vive study of dihydroquercetin genotoxicity.

Genotoxic properties of dihydroquercetin were in vivo studied by the method of chromosome aberrations counting and DNA-comet assay. Dihydroquercetin administered repeatedly (5 times, 0.15 and 1.5 mg/kg) or once in doses of 15, 150, and 2000 mg/kg induced no DNA damages in mouse bone marrow, blood, liver, and rectal cells. Single administration of this preparation in doses of 1.5 and 150 mg/kg and 5-fold administration in a dose of 1.5 mg/kg had no effect on the level of chromosome aberrations in mouse bone marrow cells.

[The antimutagenic effect of adaptation to stress]. / Antimutagennyi éffekt adaptatsii k stressu.

C57BL mice were adapted to moderate periodic hypoxia and repeated electric pain stresses of limited intensity. These animals adapted to each of the factors and control animals were given the potent mutagen, free radical oxidation activator dioxidine in a single dose of 300 mg/kg. Dioxidine administered to unadapted animals resulted in chromosomal aberrations in 11% of stem bone marrow cells mainly due to the appearance of single and multiple chromosomes. Preadaptation to stress decreased the number of these dioxidine-induced chromosomal aberrations nearly twice. Adaptation to periodic hypoxia had no defensive action. As previously shown, adaptation to repeated stresses leads to the accumulation of heat-shock proteins (HSP) in the cellular nuclei of animals and prevents the degradation of isolated nuclei when single-chain DNA is added. Adaptation to hypoxia does not cause nuclear accumulation of HSP or prevents their degradation when unicellular DNA is supplemented. This suggests that the antimutagenic effect of stress adaptation is likely to be accounted for by the stabilizing action of HSP.

Antimutagenic activity of lipidovit.

Antimutagenic properties of Lipidovit produced from the biomass of Blakeslea trispora fungi was studied by its effect on induction of chromosome aberrations by chemical mutagens dioxidine and cyclophosphamide in mouse bone marrow cells. Antimutagenic activity of Lipidovit depended on the scheme of treatment. It was maximum during pretreatment of animals (5 day) or administration in combination with mutagens (5 days). The preparation was ineffective after single administration in combination with mutagens. Lipidovit exhibited no comutagenic properties.