Search

Cytotoxic and genotoxic effects of flurochloridone (FLC) and its formulations Twin Pack Gold® and Rainbow® were evaluated in CHO-K1 cells. Using the alkaline single-cell gel electrophoresis (SCGE) assay, we observed that FLC (15 μg/ml), Twin Pack Gold® or Rainbow® induced primary DNA damage, increasing the frequency of damaged nucleoids. Vitamin E pretreatment did not modify the effect. Decreased cell viability was observed only in Twin Pack Gold®-treated cultures and was significantly ameliorated by vitamin E. Post-treatment of herbicide-damaged CHO-K1 cells with the enzymes Endo III or Fpg did not increase FLC-, Twin Pack Gold®-, or Rainbow®-induced DNA damage. These results demonstrate that neither FLC nor FLC-based formulations induce DNA damage through hydroxyl radical or lipid alkoxyl radical production, and that the induced DNA lesions were not related to oxidative damage at the purine/pyrimidine level. Our observations strongly suggest that the cytotoxic effects observed after Twin Pack Gold® exposure are due to the excipients contained within the technical formulation rather than FLC itself. Fil: Soloneski, Sonia Maria Elsa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Cátedra de Citología; Argentina Fil: Nikoloff, Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Cátedra de Citología; Argentina Fil: Larramendy, Marcelo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Cátedra de Citología; Argentina

Acute toxicity and genotoxicity of the dicamba-based commercial herbicide formulation Banvel® were evaluated on Cnesterodon decemmaculatus (Pisces, Poeciliidae) exposed under laboratory conditions. A lethal effect was used as the end point for mortality, whereas frequency of micronuclei (MNs) and DNA single-strand breaks evaluated by the single cell gel electrophoresis assay were employed as end points for genotoxicity. Mortality studies revealed an LC50 96 h value of 1639 mg/L (range, 1471–1808) of dicamba. Furthermore, behavioral changes, e.g., gathering at the bottom of the aquarium, slowness in motion, abnormal swimming, and slow reaction, were observed. Whereas increased frequency of MNs was observed when 1229 mg/L dicamba was assayed for 48 h, no induction of MNs was observed in fish exposed to the herbicide for 96 h, regardless of the concentration of dicamba. Furthermore, other nuclear abnormalities, i.e., binucleated cells and lobed and notched nuclei, were induced in fish exposed for 48 h but not 96 h. Increase in the genetic damage index was observed in those treatments (lasting for both 48 and 96 h) within the 410–1229 mg/L dicamba concentration-range. This study represents the first evidence of acute lethal and sublethal effects exerted by dicamba on a piscine species native to Argentina. The results could indicate that dicamba-based formulation Banvel® is the less toxic emerging pollutant reported so far for C. decemmaculatus. Finally, our findings highlight the properties of this herbicide that jeopardize nontarget living species exposed to this agrochemical. Fil: Ruiz de Arcaute, Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Cátedra de Citología; Argentina Fil: Soloneski, Sonia Maria Elsa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Cátedra de Citología; Argentina Fil: Larramendy, Marcelo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Cátedra de Citología; Argentina

Zineb [ethylene bis(dithiocarbamate) zinc] is a widely employed foliar fungicide for agricultural and industrial applications. Allium cepa L. is a reliable model for the assessment of xenobiotic genotoxicity and cytotoxicity. We evaluated the effects of the zineb-containing commercial formulation Azzurro(®) (70% zineb) in cell cycle stages of the meristem root cells of A. cepa. The mitotic index (MI), chromosomal aberrations at anaphase/telophase (CAs), micronuclei (MN), and abnormalities in immunodetected microtubule structures, e.g., preprophasic band (PPB), mitotic spindle (MS), and phragmoplast (Phrag), were used as end-points. Azzurro(®) (1 and 10μg/ml) induced a significant increase in the frequency of CAs (P

The acute toxicity, genotoxicity, and cytotoxicity of the pirimicarb-containing commercial-formulation carbamate insecticide Aficida ® (50% pirimicarb) were evaluated on Cnesterodon decemmaculatus (Pisces, Poeciliidae) exposed under laboratory conditions. Micronucleus (MN) induction as well as alterations in the erythrocytes:erythroblasts ratios were employed as end-points for genotoxicity and cytotoxicity, respectively. Cr(VI) and cyclophosphamide were used as positive controls for the toxicity and geno-cytotoxicity assays, respectively. Mean values of 344.3 and 225.5 mg Aficida ® /L were determined for LC-50 24 h and LC-50 96 h , respectively. In 48 h-exposed fish, a MN increase was found in Aficida ® -treated fish in the 50–157 mg/L concentration range. When fish were exposed to Aficida ® for 96 h, only those animals treated at 50–100 mg/L showed an increase in MN frequency. Cellular cytotoxicity, revealed by a decreased proportion of circulating erythrocytes and an enhancement of erythroblasts, was found after 48 h of exposure in 50–157 mg Aficida ® /L-treated fish, while, after 96 h exposure, only 100–157 mg Aficida ® /L induced the same effect. This species provides a useful experimental model for the biomonitoring of aquatic ecosystems.

The in vitro geno- and cytotoxicity exerted by the N-methylcarbamate pesticide carbofuran (CF) and its commercial formulation furadan (F) were studied in Chinese hamster ovary (CHO(K1)) cells by several bioassays for both genotoxicity (e.g., the sister chromatid exchange (SCE) and micronuclei (MNi) frequencies), and cytotoxicity (e.g., cell-cycle progression, mitotic index (MI), 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and neutral red (NR)). Both CF and F activities were tested within the range of 5-100 microg/ml. CF within a 10-100 microg/ml concentration-range induced a significant dependent increase of SCE frequency and MNi over control values. At the same concentration-range, F increased significantly the SCE frequencies over control values although in a non-dependent manner while only an enhanced frequency of MNi was found in those 50 microg/ml-treated cultures. No binucleated cytokinesis-block cells were found in 100 microg/ml F-treated cultures. The NDI index revealed a delay in the onset of cell-division with 50 and 100 microg/ml of CF and F, respectively. The delayed rate of nuclear division induced by 100 microg/ml of F was higher than that induced by an equal concentration of CF. CF and F induced both a significant concentration-dependent delay in cell-cycle progression and a decrease in the proliferative replication index within 5-100 microg/ml and 50-100 microg/ml concentration-range, respectively. Decreased cell viability was found in up to 26% and 47% in 100 microg/ml CF- and F-treated cultures, respectively. The NR and MTT assays revealed a clear cell growth inhibition when concentrations of 50 and 100 microg/ml of either CF or F were employed. Accordingly, the results highlight that CF by itself and F, even in a greater extend exerts both genotoxicity and cytotoxicity in mammalian cells in culture, at least in CHOK1 cells.

The sister chromatid exchange (SCE) frequency, the cell-cycle progression analysis, and the single cell gel electrophoresis technique (SCGE, comet assay) were employed as genetic end-points to investigate the geno- and citotoxicity exerted by dicamba and one of its commercial formulation banvel (dicamba 57.71%) on Chinese hamster ovary (CHO) cells. Log-phase cells were treated with 1.0-500.0 microg/ml of the herbicides and harvested 24 h later for SCE and cell-cycle progression analyses. All concentrations assessed of both test compounds induced higher SCE frequencies over control values. SCEs increased in a non-dose-dependent manner neither for the pure compound (r=0.48; P>0.05) nor for the commercial formulation (r=0.58, P>0.05). For the 200.0 microg/ml and 500.0 microg/ml dicamba doses and the 500.0 microg/ml banvel dose, a significant delay in the cell-cycle progression was found. A regression test showed that the proliferation rate index decreased as a function of either the concentration of dicamba (r=-0.98, P

Abnormalities induced in the mitotic spindle by zineb and azzurro (1.0-25.0 micro g/ml, 24h) were evaluated in Chinese hamster ovary (CHO) and HeLa cells, and in non-transformed human fibroblasts (NTHF). Spindles were stained with FITC-conjugated anti-beta tubulin. Treatment with 10.0 micro g/ml of zineb induced complete inhibition of cell viability in NTHF cells while 10.0 micro g/ml of azzurro decreased cell growth down to 62%. Higher doses of both compounds induced cell death. In HeLa and CHO cells, 15.0 micro g/ml of zineb and 10.0-15.0 micro g/ml of azzurro decreased viability, whereas 25.0 micro g/ml of both compounds was cytotoxic. A significantly decreased mitotic index (MI) was observed in NTHF treated with 5.0 micro g/ml zineb or azzurro, whereas 10.0 micro g/ml of both chemicals were necessary to induce the same phenomenon in HeLa and CHO cells. Treatment with 1.0-5.0 micro g/ml of zineb or azzurro induced a dose-dependent increase of degenerated spindles in NTHF and the number of degenerated or multipolar spindles in HeLa and CHO cells increased in a dose-dependent manner with 1.0-10.0 micro g/ml zineb and azzurro. Although zineb and azzurro were able to induce mitotic spindle abnormalities in all cell types, non-transformed cells were less resistant than immortalized cells.

Single cell gel electrophoresis (SCGE) was used to analyse dithiocarbamate zineb- and the zineb-containing technical formulation azzurro-induced DNA damage and repair in CHO cells. Cells were treated with zineb (50.0 μg/ml) or azzurro (100.0 μg/ml) for 80 min, washed and reincubated in pesticide-free medium for 0–12 h until SCGE. Viability of treated cells (0 h) did not differ from control remaining unchanged up to 6 h of incubation. After 12 h, viability decreased up to 70 and 54% in zineb- and azzurro-treated cultures, respectively. SCGE revealed at 0 h the absence of undamaged cells and an increase of slightly damaged and damaged cells in zineb-treated cultures or by an increase in damaged cells in azzurro-treated cultures. For both chemicals, a time-dependent repair of pesticide-induced DNA damage within a 0–12 h post-treatment incubation period was observed. Overall, damaged cells decreased as a function of the repair time for both pesticides while the slightly damaged cells decreased as a function of the repair time of zineb-induced DNA damage. Concomitantly, a time-dependent increase of undamaged cells was observed within the 0.5–12 h repair time for both pesticides. At 12 h after treatment, no differences in the frequencies of undamaged, slightly damaged and damaged cells were found between both zineb- or azzurro-treated cultures and control values as well as between zineb- and azzurro-treated cells. Immediately after exposure, nuclear DNA from zineb and azzurro-treated cells were larger and wider than nuclear DNA from untreated cells. When damaged cells were allowed to repair, a time-dependent decrease of the amount of free DNA migrating fragments was observed committed only to damaged cells but not in slightly or undamaged cells. On the other hand, no time-dependent alteration on nuclear DNA width within the 0–12 h repair period was observed.

The in vitro genotoxicity exerted by the dithiocarbamate fungicide zineb, and its commercial formulation azzurro, were studied in Chinese hamster ovary (CHO) cells by the analysis of the sister chromatid exchange (SCE), cell-cycle progression and single cell gel electrophoresis (SCGE) assays. Both zineb and azzurro activities were tested within the range of 0.1–100.0 μg/ml. Concentrations of 0.1–25.0 μg/ml of zineb or azzurro induced a significant dose-dependent increase in SCE frequency over control values. For both test compounds, while doses ranging from 0.1 to 1.0 μg/ml did not alter the rate of cell proliferation, a significant delay in cell-cycle progression was observed within the 5.0–25.0 μg/ml dose-range. A regression test showed that either the proliferative replication index or the mitotic activity of cultures decreased as a function of the pesticide concentration within the 1.0–25.0 μg/ml dose-range. Doses higher than 50.0 μg/ml were cytotoxic. SCGE assay revealed an increase in zineb-induced DNA damage by enhancing the proportion of slightly damaged cells in the 25.0–100.0 μg/ml dose-range and by increasing in a dose-dependent manner the proportion of damaged cells within the 1.0–100.0 μg/ml dose-range. Overall, image analysis showed statistically significant positive relationships between zineb concentration and DNA damage (expressed by image length and width) and between length and width of the damaged cells. In azzurro-treated cells, only when 100.00 μg/ml was employed a significant increase in the frequency of damaged cells over control values affecting the totality of the cells was observed only when 100.0 μg/ml was employed. When lower doses were employed, no DNA damage was revealed. Based on these results, the evaluation of zineb as a genotoxic/non-genotoxic compound for human health should be reconsidered. Even though we demonstrate that the pesticide induces large DNA alterations in vitro, does no necessarily mean that the chemical should be considered clastogenic.