Maria Clara Gimmler-Luz

Suppressing effect of vanillin on chromosome aberrations that occur spontaneously or are induced by mitomycin C in the germ cell line of Drosophila melanogaster

In order to investigate the anticlastogenic effect of vanillin on ring-X loss, D. melanogaster females exposed to different vanillin concentrations were crossed with non-treated, MMC- or MMS-treated males. The results obtained with this in vivo investigation showed a significant inhibition of vanillin in the frequencies of spontaneous ring-X loss--59, 56, 38 and 36%--at the different concentrations used. In addition, vanillin treatment caused a significant suppression of MMC-induced ring-X loss. This decrease was observed only in the first 3 days after the interruption of vanillin treatment and at the concentrations of 0.5 and 1% of this flavoring agent. In contrast, vanillin did not show any effect on chromosome loss provoked by MMS. Therefore, the ring-X loss-decreasing effect of vanillin seemed to depend on the quality of DNA lesions and consequently on a specific enzymatic repair process present in the oocytes of D. melanogaster.

The effect of the pyrrolizidine alkaloid integerrimine on the chromosomes of mouse bone marrow cells

In an investigation of the action of integerrimine on chromosomes, the bone marrow was taken as target organ. Male and female mice of the C57Bl/6 strain received a single acute dose of this pyrrolizidine alkaloid, in 2 concentrations: 18.75 and 37.50 mg/kg. Bone marrow cells were collected 6, 12 and 24 h after treatment. The analysis of metaphasic chromosomes demonstrated that chromosomal damage occurs, correlated with drug concentration. The greatest frequency of chromosomal aberrations was detected 12 h after treatment.

Co-mutagenic effect of tannic acid on ring-X chromosome loss induced by mitomycin C in sperm cells of Drosophila melanogaster

To investigate the effects of tannic acid (TA) on ring-X chromosome loss, Drosophila melanogaster females exposed to different TA concentrations were crossed with untreated, methyl methanesulfonate (MMS)- or mitomycin C (MMC)-treated males which carried a ring-X chromosome. Progeny were analyzed for loss of the ring-X. The results of this in vivo study showed that TA had no suppressing effect on chromosome loss occurring spontaneously or after induction by MMS in mature spermatozoa. In contrast, TA caused a significant increase in the frequency of MMC-induced ring-X loss. The increase caused by this co-mutagenic effect reached values of 34, 33 and 40% at TA concentrations of 10, 25 and 50 mM, respectively. These increments may reflect the action of TA on a uvrABC-type enzyme which, by increasing the double-strand breaks (DSBs), somehow interferes with the post-replicational repair responsible for the final DSB correction.

Analysis of clastogenic effect of Porto Alegre drinking water supplies on mouse bone marrow cells

Studies were conducted to evaluate the clastogenic activity of drinking water from Porto Alegre and Guaíba (Rio Grande do Sul, Brazil) estuarine waters. Mouse bone marrow was the target organ. C57B1/6 male and female mice received the water samples as their only liquid supply. Bone marrow cells were collected on the 16th day after the beginning of treatment. The analysis of metaphases demonstrated that the water supplies did not increase the structural chromosome aberration frequencies compared to the control groups. Concerning numerical alterations, only one treated female group showed a significant difference (loss of one chromosome) when compared to the control group, but this result is not considered relevant.

Transplacental inhibitory effect of carrot juice on the clastogenicity of cyclophosphamide in mice

O dano genetico durante o periodo pre-natal pode ser uma importante fonte de alteracoes neoplasicas e de outras doencas durante a vida pos-natal. O beta-caroteno (sC) e considerado um dos mais importantes anticarcinogenos da dieta e pode proteger celulas de mamiferos contra eventos genotoxicos. Como a cenoura e a fonte classica do sC, nos decidimos testar a modulacao do suco de cenoura fresco (CaJ) sobre a genotoxicidade induzida pela ciclofosfamida (CP) no tecido eritropoietico materno e fetal. O tratamento de femeas BALB/c com o CaJ ocorreu desde o 7o dia gestacional. Nos observamos, no 16o dia gestacional, que tal tratamento nao modificou a frequencia espontânea de eritrocitos policromados micronucleados (mPCE) na medula ossea materna ou no figado fetal. Quando femeas prenhes pre-tratadas com o CaJ receberam uma injecao intraperitoneal de CP (40 mg/kg) no 15o dia gestacional, 24 h depois foi observada uma frequencia de mPCE significativamente menor do que a observada no grupo tratado somente com a CP, tanto na medula ossea materna como no figado fetal. Estes resultados indicam a presenca de anticlastogenos naturais na cenoura.

Clastogenic activity of integerrimine determined in mouse micronucleus assays

The pyrrolizidine alkaloid integerrimine, obtained from Senecio brasiliensis, was tested by acute dosing at two concentrations (18.75 and 37.5 mg/kg), and at different times, to establish its ability to induce micronuclei in mouse erythrocytes. This alkaloid was able to increase the frequency of micronucleated polychromatic erythrocytes in both, bone marrow and peripheral blood erythrocytes