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Considering the limited number of studies on the biological effects on human health of cyanobacterial compounds that cause taste and odor, the present study assessed the cytotoxic and genotoxic potentials of 2-methylisoborneol (2-MIB) and geosmin (GEO) using the MTT assay and the in vitro comet and cytokinesis-block micronucleus (CBMN-Cyt) assays in human HepG2 cells. The toxicogenomics of genes responsive to DNA damage and metabolization by the exposure of cells to 2-MIB and GEO were also investigated. The results showed that concentrations of 2-MIB and GEO above 100 and 75 μg/mL, respectively, were cytotoxic to HepG2 cells. Doses of 2-MIB (12.5, 25, 50, 75 and 100 μg/mL) and GEO (12.5, 25, 50, and 75 μg/mL) were unable to induce neither DNA damage nor events associated with chromosomal instability. Similarly, no concentration of each compound induced increments in the expression of CDKN1A, GADD45α, MDM2 and TP53 DNA damage responsive genes as well as in CYP1A1 and CYP1A2 metabolizing genes. Although cytotoxicity was observed, concentrations that caused it are much higher than those expected to occur in aquatic environments. Thus, environmentally relevant concentrations of both compounds are not expected to exhibit cytotoxicity or genotoxicity to humans.

RESUMO O trabalho objetivou o estudo taxonômico de microalgas do gêneroTrachelomonas (Euglenophyceae) na Área de Proteção Ambiental (APA) do rio Ibirapuitã, localizada na fronteira sudoeste do Estado do Rio Grande do Sul. Foram amostradas 10 estações de coleta em ambientes lóticos e lênticos, no período de 2011 a 2013. As 34 amostras resultantes de quatro coletas foram obtidas com rede de plâncton com abertura de malha de 30 µm, e conservadas com formol a 4%. São apresentados os nove táxons que são novos registros para o Estado do Rio Grande do Sul, encontrados em somente três estações de coleta das 10 amostradas. Dentre esses, distinguem-se ainda por serem citados pela primeira vez para o Brasil: Trachelomonas bernardii Wolosz. f. major Defl., T. caudata Defl. f. pseudocaudata (Defl.) Pop.,T. hirta Cunha var. hirta e T. torosa (Bal.) Tell & Conf.