Freshwater planarians as novel organisms for genotoxicity testing: Analysis of chromosome aberrations

Abstract

Two freshwater species of planarians, Girardia schubarti Marcus and G. tigrina Girard, were used for measuring chromosome aberration (CA) induction under laboratory conditions. Three genotoxicants were tested: methyl methanesulfonate (MMS), a direct-acting genotoxicant; cyclophosphamide, a metabolism-dependent genotoxicant; and gamma-radiation, a clastogenic agent. All three agents produced positive responses in both species. The strongest dose-responses were detected with MMS, and, in general, G. tigrina was somewhat more sensitive to the genotoxicity of the agents than G. schubarti. This difference in sensitivity may be due to: (a) the smaller body mass of G. tigrina; (b) differences in DNA repair, which may be reflected in the marginally higher background CA frequency of G. tigrina; and/or (c) the greater number of chromosomes in G. tigrina (2N = 16) as compared with G. schubarti (2N = 8). The responses induced by gamma-radiation in the planarians were similar to or higher than those induced in cultured human lymphocytes. The CA-planarian assay has advantages for monitoring environmental genotoxicity in natural water resources or urban and industrial wastewater since planarians are characterized by (a) a relatively low number of easily analyzable chromosomes; (b) high regenerating capacity, allowing exposure of replicating cells from different parts of the same organism to different doses; (c) easy maintenance under laboratory conditions; and (d) worldwide distribution, making them available for genotoxicity tests using either in situ or controlled laboratory exposure conditions.

Estado do conhecimento dos macroturbelários (Platyhelminthes) do Brasil

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The effect of paraoxon on spermatogenesis in Dugesia gonocephala from the Chilean Altiplano: proliferation and apoptosis

“…This often involves an exogenous stimulus that causes an acute damage to tissues and provokes a strong inflammatory response (Pfister et al 2007;Pellettieri and Sanchez 2007). Incorporation studies with bromodeoxyuridine (BrdU) show that 99% of the neoblasts are labeled with BrdU after 3 days of continuous BrdU treatment (Lau et al 2007). The availability of BrdU-labeling for planarian stem cells, and thousands of planarian cDNA sequences are soon to be released into public databases (Robb and Sanchez 2002;Moraczewski et al 2008).…”

“…In these hermaphroditic animals, during the adult life stage, the male reproductive system shows a complete spermatogenesis with stability of somatic cell populations. Planarians have been used as indicators of water quality and toxic effects of various substances (Nano et al 2002;Lau et al 2007). One critical parameter appears to be the interaction between stem cells and their local tissular microenvironments.…”

Planarians as invertebrate bioindicators in freshwater environmental quality: the biomarkers approach

“…The use of aquatic organisms as biological sentinels has proved to be useful for environmental monitoring (Hutchinson et al, 1997;Bebianno et al, 2004;Zagatto & Bertoletti, 2006). Organisms in the classes of Turbellaria and, Cestoda, have been suggested as potential bioindicators for environmental pollutants (Gamo & Noreña-Janssem, 1998;Sures, 2004;Lau et al, 2007).…”