Analysis of glutathione and vitamin C effects

The alkaline single-cell gel electrophoresis (or Comet) assay was applied to evaluate the eventual DNA damage induced by the triphenolic metabolite of benzene, 1,2,4-benzenetriol (BT), in isolated human lymphocytes. Prior to BT treatment, ranging from 5 to 50 μM, a supplementation with glutathione (GSH, 350 μg/ml) was carried out to assess whether GSH may have a modulating effect on the Comet response. The effect of a fixed dose of BT was also evaluated in the presence of the exogenous antioxidant vitamin C (40 and 200 μM). Additionally, we investigated whether the polymorphism of glutathione S-transferase T1 (GSTT1) gene may affect the individual level of BT-induced DNA damage in vitro. For all donors included in the present study, BT produced a significant dose-response relationship. No clear effect of GSH preincubation was seen on the BT-induced response. On the contrary, a significant reduction of DNA damage was observed in the presence of vitamin C (at least at 200 μM). Although our data suggest some individual differences according to the GSTT1 genotype in the outcome of the Comet assay, a large number of individuals should be studied in further investigations to obtain reliable conclusions

Genomic Instability in Newborn with Short Telomeres

Telomere length is considered to be a risk factor in adults due to its proved association with cancer incidence and mortality. Since newborn present a wide interindividual variation in mean telomere length, it is relevant to demonstrate if these differences in length can act also as an early risk indicator. To answer this question, we have measured the mean telomere length of 74 samples of cord blood from newborns and studied its association with the basal genetic damage, measured as the frequency of binucleated cells carrying micronuclei. In addition, we have challenged the cells of a subgroup of individuals (N = 35) against mitomycin-C (MMC) to establish their sensitivity to induced genomic instability. Results indicate that newborn with shorter telomeres present significantly higher levels of genetic damage when compared to those with longer telomeres. In addition, the cellular response to MMC was also significantly higher among those samples from subjects with shorter telomeres. Independently of the causal mechanisms involved, our results show for the first time that telomere length at delivery influence both the basal and induced genetic damage of the individual

Contribució cromosòmica a la resposta a la selecció de les microquetes interocel·lars de Drosophila melanogaster

Hem analitzat la importancia que tenen els diferents cromosomes de Drosophila melanogaster en la manifestació del nombre de microquetes interocel·lars i hem evaluat l'efecte de les interaccions cromosomiques. L'experiment s'ha realitzat sobre vuit línies seleccionades, emprant l'analisi substitucional. Els resultats obtinguts indiquen que, malgrat que els tres cromosomes majors són portadors d'agents amb efecte sobre el caracter, la seva importancia relativa depen del tipus de selecció practicada. Així, mentre que a les línies per disminució trobem efecte clar i positiu dels cromosomes X i III, i molt poc efecte del cromosoma Il. a les línies per augment trobem que els cromosomes II i III tenen efecte clar i positiu i que, en canvi, el cromosoma X te efecte negatiu molt fort.The importance of the different chromosomes in the manifestation of interocellar bristles in Drosophila melanogaster has been analysed. This study has been carried out on eight selection lines by means of substitucional analysis. The resultats found show that although on the three major chromosomes are located agents with effect on the studied trait, their relative importance depends on the selection applied. Thus, while in the low lines there is a clear and positive effect in first and third chromosomes, and a mild effect in second chromosome, in the high lines the second and third chromosomes have a clear and positive effect and the first chromosome a very significant and negative effect