Comparative cyto- and genotoxicity of 900 MHz and 1800 MHz electromagnetic field radiations in root meristems of Allium cepa.

In the last few decades, tremendous increase in the use of wireless electronic gadgets, particularly the cell phones, has significantly enhanced the levels of electromagnetic field radiations (EMF-r) in the environment. Therefore, it is pertinent to study the effect of these radiations on biological systems including plants. We investigated comparative cytotoxic and DNA damaging effects of 900 and 1800 MHz EMF-r in Allium cepa (onion) root meristematic cells in terms of mitotic index (MI), chromosomal aberrations (CAs) and single cell gel electrophoresis (comet assay). Onion bulbs were subjected to 900 and 1800 MHz (at power densities 261 ±â€¯8.50 mW m-2 and 332 ±â€¯10.36 mW m-2, respectively) of EMF-r for 0.5 h, 1 h, 2 h, and 4 h. Root length declined by 13.2% and 12.3%, whereas root thickness was increased by 46.7% and 48.3% after 4 h exposure to 900 MHz and 1800 MHz, respectively. Cytogenetic studies exhibited clastogenic effect of EMF-r as depicted by increased CAs and MI. MI increased by 36% and 53% after 2 and 4 h exposure to 900 MHz EMF-r, whereas it increased by 41% and 67% in response to 1800 MHz EMF-r. Aberration index was increased by 41%-266% and 14%-257% during 0.5-4 h of exposure to 900 MHz and 1800 MHz, respectively, over the control. EMF-r exposure decreased % head DNA (DNAH) and increased % tail DNA (DNAT) and olive tail moment (OTM) at both 900 and 1800 EMF-r. In 4 h exposure treatments, head DNA (%) declined by 19% and 23% at 900 MHz and 1800 MHz, respectively. DNAT and OTM were increased by 2.3 and 3.7 fold upon exposure to 900 MHz EMF-r over that in the control, whereas 2.8 and 5.8 fold increase was observed in response to 1800 MHz EMF-r exposure for 4 h and the difference was statistically significant. The study concludes that EMF-r in the communication range (900 and 1800 MHz) adversely affect root meristems in plants and induce cytotoxic and DNA damage. EMF-r induced DNA damage was more pronounced at 1800 MHz than that at 900 MHz.

Genetic effects in Helix aspersa near a coal plant revealed by the micronucleus test.

Coal plants can be a major source of mutagenic pollutants. In this study we used the common land snail Helix aspersa, to detect the mutagenic effect of pollution from a coal plant in central Italy applying the micronucleus test (MN) on snail's haemocytes and evaluating trace elements concentration (As Cd, Pb, Hg, and Zn) in soil and snails. Snails from a biological farm were exposed for 13 days in five locations at different distances from the plant. Wild snails collected in the same locations were also analysed. MN frequency in exposed snails was significantly higher in four locations within 10 km from to the plant, with respect to the control and the farthest location. Comparing the MN frequency between farmed and wild snails, a significantly higher frequency emerged for the exposed snails in all locations except the farthest, likely indicating adaptation or selection of the wild organisms due to chronic exposure to pollutants. In natural snails significantly higher MN frequencies with near the plant emerged as well. Trace elements analysis showed significant correlations between MN frequencies and both Zn and As concentrations in soil, for both exposed and wild snails, and Zn and Pb concentrations in exposed snails. Our results were consistent with those previously obtained when evaluating primary DNA damage in natural snails from the same area and show that the snails near the plant were affected by a permanent cytogenetic damage. Moreover, they confirm the suitability of snails for biomonitoring the presence of pollutants with mutagenic effect.

The radiomimetic compound streptonigrin induces persistent telomere dysfunction in mammalian cells.

We analyzed the chromosomal aberrations involving telomeres in the progeny of mammalian cells exposed to the radiomimetic compound streptonigrin (SN) in order to determine if this antineoplastic drug induces long-term telomere instability. To this end, rat cells (ADIPO-P2 cell line, derived from adipose cells from Sprague-Dawley rat) were treated with a single concentration of SN (100ng/ml), and chromosomal aberrations were analyzed 18h and 10 and 15 days after treatment by using PNA-FISH with a pan-telomeric probe [Cy3-(CCCTAA)3] to detect (TTAGGG)n repeats. Cytogenetic analysis revealed a higher frequency of telomere dysfunction-related aberrations (additional telomeric FISH signals, extra-chromosomal telomeric FISH signals, and telomere FISH signal loss and duplications) in SN-exposed cultures vs. untreated cultures at every time points analyzed. The yield of SN-induced aberrations remained very similar at 18h, 10 days as well as 15 days after treatment. Thus, our data demonstrate that SN induces persistent telomere dysfunction in mammalian cells. Moreover, we found that the level of telomerase activity in SN-treated cells was significantly lower (up to 77%) than that of untreated control cells at each time points analyzed. This fact suggests that telomerase could be involved in SN-induced telomere dysfunction.

Aneugenic, clastogenic, and multi-toxic effects of diethyl phthalate exposure.

Diethyl phthalate (DEP) is a compound which is used in many industrial fields, especially in cosmetic sector and causes contamination in air, water, and soil due to its widespread usage. In this study, the potential toxic effects of DEP were investigated by using physiological, anatomical, biochemical, and cytogenetic parameters in Allium cepa. The micronucleus (MN) test specifically aimed to elucidate the aneugenic and clastogenic effects of DEP. Physiological effects were determined by germination percentage, root length, weight gain parameters, and cytogenetic effects were investigated by mitotic index (MI) and chromosomal abnormality (CA) test. Malondialdehyde (MDA) level, catalase (CAT), and superoxide dismutase (SOD) activities were investigated as oxidative damage indicators and structural changes were investigated with anatomical cross sections. For this purpose, Allium cepa bulbs were divided into four groups as control and application groups and the application groups were germinated with 1.0, 2.2, and 4.4 µM DEP for 72 h. As a result, it was determined that germination percentage, weight gain and root length decreased, CA frequency, MDA level, SOD, and CAT activities were increased in DEP-treated groups when compared with the control group. DEP has been found to induce CA in root tip cells such as fragment, chromosome bridge, c-mitosis, sticky chromosome, and unequal chromatin distribution. When MN formations induced by DEP application were examined, both large-scale and small-scale MNs were determined. MN formation in both sizes indicates that DEP has both clastogenic and aneugenic effects. And also, it was found that DEP application caused structural changes and especially anatomic damages such as necrosis in 4.4 µM DEP application. As a result, it was found that DEP caused various toxic effects depending on the dose and that A. cepa test material was a useful indicator in determining these effects.

The methylating agent streptozotocin induces persistent telomere dysfunction in mammalian cells.

We analyzed chromosomal aberrations involving telomeres in the progeny of mammalian cells exposed to the methylating agent and antineoplastic/diabetogenic drug streptozotocin (STZ), to test whether it induces long-term telomere instability (by chromosome end loss and/or telomere dysfunction). Rat cells (ADIPO-P2 cell line, derived from Sprague-Dawley rat adipose cells) were treated with a single concentration of STZ (2mM). Chromosomal aberrations were analyzed 18h, 10 days, and 15 days after treatment, using PNA-FISH with a pan-telomeric probe [Cy3-(CCCTAA)3] to detect (TTAGGG)n repeats. Cytogenetic analysis revealed a higher frequency of chromosomal aberrations in STZ-exposed cultures vs. untreated cultures at each time point analyzed. The yield of induced aberrations was very similar at each time point. Induction of aberrations not involving telomere dysfunction was only observed 18h and 15 days after treatment, whereas induction of telomere dysfunction-related aberrations by STZ (mainly in the form of telomere FISH signal loss and duplications, most of them chromatid-type aberrations) was observed at each time point. Our results show that STZ induces persistent telomere instability in mammalian cells, cytogenetically manifested as telomere dysfunction-related chromosomal aberrations. Neither telomere length nor telomerase activity is related to the telomere dysfunction.

Genotoxicity of tungsten carbide-cobalt (WC-Co) nanoparticles in vitro: mechanisms-of-action studies.

We showed previously that tungsten carbide-cobalt (WC-Co) nanoparticles (NP) can be used as a nanoparticulate positive control in some in vitro mammalian genotoxicity assays. Here, we investigate the mechanisms of action involved in WC-Co NP genotoxicity in L5178Y mouse lymphoma cells and primary human lymphocytes, in vitro. Data from the micronucleus assay coupled with centromere staining and from the chromosome-aberration assay show the involvement of both clastogenic and aneugenic events. Experiments with the formamidopyrimidine DNA glycosylase (FPG)-modified comet assay showed a slight (non-significant) increase in FPG-sensitive sites in the L5178Y mouse lymphoma cells but not in the human lymphocytes. Electron paramagnetic resonance spin-trapping results showed the presence of hydroxyl radicals (•OH) in WC-Co NP suspensions, with or without cells, but with time-dependent production in the presence of cells. However, a significant difference in •OH production was observed between human lymphocytes from two different donors. Using H2O2, we showed that WC-Co NP can participate in Fenton-like reactions. Thus, •OH might be produced either via intrinsic generation by WC-Co NP or through a Fenton-like reaction in the presence of cells.

Bone distribution study of anti leprotic drug clofazimine in rat bone marrow cells by a sensitive reverse phase liquid chromatography method.

The aim of the present study was to investigate the distribution of clofazimine (CLF) in rat bone marrow cells by a validated reverse phase high performance liquid chromatography. CLF and chlorzoxazone (I.S) were extracted by liquid-liquid extraction from plasma and rat bone marrow cells. The chromatographic separation was performed in isocratic mode by the mobile phase consisting of 10mM ammonium formate (pH 3.0 with formic acid) and acetonitrile in a ratio of 50:50 (v/v). The method was accurate and precise in the linear range of 15.6-2000.0 ng/mL with a correlation coefficient (r(2)) of 0.996 and 0.995 in rat plasma and bone marrow cells, respectively. After single oral dose of 20mg/kg, the maximum concentration of CLF in plasma and bone marrow cells were obtained at 12h with the concentrations of 593.2 and 915.4 ng/mL, respectively. The AUC0-t and mean elimination half life (t1/2) of CLF in bone marrow cells were 54339.02 ng h/mL and 52.46 h, respectively, which signified the low body clearance and high distribution of CLF in bone marrow cells. The single oral dose pharmacokinetic investigation was confirmed the CLF endure for a long period in rat due to high distribution in various tissues. The developed method was successfully applied to the estimation of the pharmacokinetic parameters of CLF in plasma and bone marrow cells after administration of single oral dose of 20mg/kg to rats.