Comparative analysis of sister-chromatid exchanges in plant and human chromosomes

Monitoring urban air particulate matter (fractions PM 2.5 and PM 10) genotoxicity by plant systems and human cells in vitro: a comparative analysis

Increased incidence of mortality and sickness due to cardiopulmonary complications has been associated with elevated levels of urban air particles (UAP), with an aerodynamic diameter of 10 microm (PM 10) and 2.5 microm (PM 2.5). In the present report alternative plant systems and human cells in vitro are associated with human hazard and genotoxic risk assessment of UAP. The genotoxic activities associated with the coarse (PM 10) and the fine fraction (PM 2.5) of airborne particulates have been analyzed by evaluating micronuclei induction and/or sister-chromatid exchange (SCE) using in vitro models of Daucus carota and HS 27 human fibroblast cell suspensions and Zea mays root meristems. Results show variability in the response of the test systems and indicate that the mutagenicity trend in both plant and human cell cultures was directly correlated to the concentration of carbon-rich particles in the fraction of the PM 2.5 airborne particulates. Moreover, in plant tissues, the frequency of micronuclei and SCE was related to an enhancement of the specific activity of the stress-related enzyme peroxidase.

Comparison of the yields of translocations and dicentrics measured using conventional Giemsa staining and chromosome painting

Inconsistent results have been reported regarding the yields of translocations and dicentrics measured using chromosome painting. This inconsistency may be due to mis-scoring of dicentrics as translocations because painting is unsuited to identify centromere positions. In the present study, chromosome aberrations exclusively in the first mitosis after irradiation were analyzed using human peripheral lymphocytes. When identical metaphases were analyzed by both painting and conventional Giemsa staining, which is the most reliable method to locate centromeres, equal frequencies of translocations and dicentrics were observed.