Frequency Of Chromosomal Aberrations Research Articles

Mitotic chromosomal abnormalities and DNA polymorphism in the Nile tilapia (Oreochromis niloticus, Linnaeus, 1758) as a biomarker for water pollution by heavy metals.

Mitotic chromosomal aberrations and DNA polymorphism (RAPD marker) were carried out on the Nile tilapia Oreochromis niloticus collected from five sites in Minia governorate, Egypt to test their applicability as biomonitors for heavy metal contaminants of water. The diploid chromosome number of O. niloticus population was 2 n=44. Different types of chromosomal aberrations were recorded (e.g., deletion, ring, centromeric attenuation, end-to-end association, dicentric chromosome, stickiness chromosomes, endomitosis, fragments and chromatid gap). The chromosomal aberrations varied between O. niloticus population collected from five sites, and the most common type was ring (R) chromosomes. Samples obtained from Bahr Yousef and Irrigation drain exhibited the highest aberration frequency. The frequency of chromosomal aberration was positively correlated with the concentration of heavy metals where their concentration in the surface water of Irrigation drain and Bahr Yousef exceeded the limits defined by WHO as well as the concentration of Pb in muscles. The RAPD marker was also used to identify genetic variation among Nile tilapia samples collected from five different water sources. It created polymorphic and unique bands that can be used as genetic markers to track DNA variations. The dendrogram also revealed that exposure to heavy metal pollution causes gradual accumulation of variance, whereas areas subjected to environmental stress showed higher genetic variation and clustered together.

Evaluation the Effect of Topiramate on the Induction Genotoxicity in Obesity Patients

Topiramate ( sulfamate - substituted monosaccharide) a weight loss drug used a pharmacotherapeutic agent for obesity , a study was performed to evaluate the effect of the topiramate to induce chromosome aberrations (CA) and sister chromatid exchange (SCE) in lymphocytes of obesity patients . CA and SCE, a sensitive measure of chromosome damage , were counted in peripheral blood lymphocytes from 32 obesity patients treated with topiramate dose ( 6 months with 81mg/day , 12 months with 129 mg/day) and 16 healthy person as control group who had never received topiramate and other drugs during the period of the study. All of the treated patients with topiramate ,have cells with CA and abnormal SCE frequencies, in analysis ,obesity patients, was significantly increased CA in 129mg/day and 81mg/day topiramate dose compared with control ( 4.08±1.51 and 3.56±1.21 ) respectively, vs (1.40± 0.81),(P<0.01).Furthermore, a significantly higher SCE/Cell frequency (10.42 ±0.75and 8.75±0.38) in treated obesity patients with 129 mg/day ,81mg/day dose respectively comparison with their control group (5.91±0.31), (P<0.001).
 The chromosome damage and genotoxics are related to the daily dose and may be determined by the duration of treatment .We conclude the patients treatment with topiramate may be associated with genetic toxicity according to byproducts of drug metabolism.

In vitro genotoxic and antigenotoxic effects of an exopolysaccharide isolated from Lactobacillus salivarius KC27L

Exopolysaccharide isolated from Lactobacillus salivarius (new genus name Ligilactobacillus) KC27L strain (EPSKC27L) exhibits antioxidant properties with 1,1-diphenyl-2-picrylhydrazase (DPPH) radical and superoxide anion radical (O2-.) scavenging effect and iron ion (Fe2+) chelating activity. This study aimed to investigate the in vitro genotoxic effects of EPSKC27L alone (12.50, 25.00, 50.00, and 100.00 μg/mL) and its antigenotoxic activity against DNA damage induced by mitomycin-C (MMC; 0.20 μg/mL), methyl methanesulfonate (MMS; 5.00 μg/mL), and hydrogen peroxide (H2O2; 100 μM). For this purpose, chromosome aberration (CA), sister chromatid exchange (SCE), micronucleus (MN), and comet assays were performed in human peripheral lymphocytes. In addition, the structure of EPSKC27L was investigated in the scanning electron microscope (SEM). EPSKC27L alone did not cause a significant genotoxic effect in CA, SCE, MN, and comet tests. EPSKC27L significantly decreased the frequency of CA, SCE, and MN induced by MMC and MMS. EPSKC27L also significantly reduced DNA damage induced by H2O2. This study showed that the EPSKC27L alone has no genotoxic risk at these concentrations and shows antigenotoxic activity against MMC, MMS, and H2O2. Consequently, EPSKC27L was found to exhibit chemopreventive activity against genotoxic agents. This effect is believed to be due to the antioxidant properties of EPSKC27L.

Chromosomal instability (CIN) in HAP1 cell lines revealed by multiplex fluorescence in situ hybridisation (M-FISH)

BackgroundHAP1, a near-haploid human leukemic cancer cell line is often used in combination with CRISPR-Cas9 gene editing technology for genetic screens. HAP1 carries the Philadelphia chromosome (Ph) and an additional ~ 30 Mb fragment of chromosome 15 inserted into chromosome 19. The potential use of an in vitro cell line as a model system in biomedical research studies depends on its ability to maintain genome stability. Being a cancer cell line with a near-haploid genome, HAP1 is prone to genetic instability, which is further compounded by its tendency to diploidise in culture spontaneously. Moreover, CRISPR-Cas9 gene editing coupled with prolonged in-vitro cell culturing has the potential to induce unintended ‘off-target’ cytogenetic mutations.To gain an insight into chromosomal instability (CIN) and karyotype heterogeneity, 19 HAP1 cell lines were cytogenetically characterised, 17 of which were near-haploids and two double-haploids, using multiplex fluorescence in situ hybridisation (M-FISH), at single cell resolution. We focused on novel numerical (N) and structural (S) CIN and discussed the potential causal factors for the observed instability. For each cell line we examined its ploidy, gene editing status and its length of in-vitro cell culturing.ResultsSixteen of the 19 cell lines had been gene edited with passage numbers ranging from 10 to 35. Diploidisation in 17 near-haploid cell lines ranged from 4 to 35% and percentage of N- and S-CIN in [1n] and [2n] metaphases ranged from 7 to 50% with two cell lines showing no CIN. Percentage of cells with CIN in the two double-haploid cell lines were 96% and 100% respectively. The most common S-CIN observed was deletion followed by translocation of both types, non-reciprocal and Robertsonian. Interestingly, we observed a prevalence of S-CIN associated with chromosome 13 in both near-and double-haploid cell lines, with a high incidence of Robertsonian translocation involving chromosome 13. Furthermore, locus-specific BAC (bacterial artificial chromosome) FISH enabled us to show for the first time that the additional chromosome 15 fragment is inserted into the p-arm rather than the q-arm of chromosome 19 of the HAP1 genome.ConclusionOur study revealed a high incidence of CIN leading to karyotype heterogeneity in majority of the HAP1 cell lines with the number of chromosomal aberrations varying between cell lines. A noteworthy observation was the high frequency of structural chromosomal aberrations associated with chromosome 13. We showed that CRISPR-Cas9 gene editing technology in combination with spontaneous diploidisation and prolonged in-vitro cell culturing is potentially instrumental in inducing further chromosomal rearrangements in the HAP1 cell lines with existing CIN. We highlight the importance of maintaining cell lines at low passage and the need for regular monitoring to prevent implications in downstream applications. Our study also established that the additional fragment of chromosome 15 in the HAP1 genome is inserted into chromosome 19p rather than 19q.

Exposure of Pisum sativum L. Seeds to Methomyl and Imidacloprid Cause Genotoxic Effects in Pollen-Mother Cells

Pesticides are commonly used in modern agricultural systems to protect the plants from pests. Even though they potentially increase the crop yield, they have undesirable toxic effects on the consumers of plant products and nontarget host plants. However, there are limited studies to demonstrate the cytological changes induced by pesticides on plant cells. In the present study, we assess the cytological changes induced by two most commonly used insecticides, methomyl (ME) and imidacloprid (IM), using Pisum sativum L. as model plant system. P. sativum seeds were exposed to various concentrations of ME and IM (0.1, 0.2, 0.3, 0.4 and 0.5%) for 1, 3, and 6 h, and their effects on seed germination (SG), radicle length (RL), mitotic index (MI), chromosomal aberrations frequency (CAF), and micronucleus frequency (MNF) were studied. The results indicate that these insecticides decrease MI in root-tip cells, and increase in the MNF in pollen-mother cells in a dose-dependent manner. Additionally, insecticide-treated groups showed a dose- and time-dependent increase in the percentage of aberrant meiotic cells. Clumped nuclei (CNU), stickiness (STC), bridges (BRs), laggards (LGs), secondary association (SA), and precocious separation (PS) were among the frequently observed anomalies. The findings of this study indicate that commonly used insecticides ME and IM have substantial genotoxic effects on the root-tip and pollen-mother cells of P. sativum L.

Frequencies of Chromosome Aberrations are Lower in Splenic Lymphocytes from Mice Continuously Exposed to Very Low-Dose-Rate Gamma Rays Compared with Non-Irradiated Control Mice.

Chromosome aberrations have been one of the most sensitive and reliable biomarkers of exposure to ionizing radiation. Using the multiplex fluorescence in situ hybridization (M-FISH) technique, we compared the changes, over time, in the frequencies of translocations and of dicentric chromosomes in the splenic lymphocytes from specific pathogen-free (SPF) C3H/HeN female mice continuously exposed to 0.05 mGy/day (18.25 mGy/year) gamma rays for 125 to 700 days (total accumulated doses: 6.25-35 mGy) with age-matched non-irradiated controls. Results show that the frequencies of translocations and of dicentric chromosomes increased significantly over time in both irradiated and non-irradiated control mice, and that the frequencies were significantly lower, not higher, in the irradiated mice, which differs from our previous reports of increased chromosome aberration frequencies at higher radiation dose rates of 1 mGy/day and 20 mGy/day. These results will be useful when considering the radiation risk at very low-dose rates comparable to regulatory dose limits.

Frequencies of Chromosome Aberrations are Lower in Splenic Lymphocytes from Mice Continuously Exposed to Very Low-Dose-Rate Gamma Rays Compared with Non-Irradiated Control Mice.

Chromosome aberrations have been one of the most sensitive and reliable biomarkers of exposure to ionizing radiation. Using the multiplex fluorescence in situ hybridization (M-FISH) technique, we compared the changes, over time, in the frequencies of translocations and of dicentric chromosomes in the splenic lymphocytes from specific pathogen-free (SPF) C3H/HeN female mice continuously exposed to 0.05 mGy/day (18.25 mGy/year) gamma rays for 125 to 700 days (total accumulated doses: 6.25-35 mGy) compare with age-matched non-irradiated controls. Results show that the frequencies of translocations and of dicentric chromosomes increased significantly over time in both irradiated and non-irradiated control mice, and that the frequencies were significantly lower, not higher, in the irradiated mice, which differs from our previous reports of increased chromosome aberration frequencies at higher radiation dose rates of 1 mGy/day and 20 mGy/day. These results will be useful when considering the radiation risk at very low-dose rates comparable to regulatory dose limits.

Ectopic expression of HIV-1 Tat modifies gene expression in cultured B cells: implications for the development of B-cell lymphomas in HIV-1-infected patients.

An increased frequency of B-cell lymphomas is observed in human immunodeficiency virus-1 (HIV-1)-infected patients, although HIV-1 does not infect B cells. Development of B-cell lymphomas may be potentially due to the action of the HIV-1 Tat protein, which is actively released from HIV-1-infected cells, on uninfected B cells. The exact mechanism of Tat-induced B-cell lymphomagenesis has not yet been precisely identified. Here, we ectopically expressed either Tat or its TatC22G mutant devoid of transactivation activity in the RPMI 8866 lymphoblastoid B cell line and performed a genome-wide analysis of host gene expression. Stable expression of both Tat and TatC22G led to substantial modifications of the host transcriptome, including pronounced changes in antiviral response and cell cycle pathways. We did not find any strong action of Tat on cell proliferation, but during prolonged culturing, Tat-expressing cells were displaced by non-expressing cells, indicating that Tat expression slightly inhibited cell growth. We also found an increased frequency of chromosome aberrations in cells expressing Tat. Thus, Tat can modify gene expression in cultured B cells, leading to subtle modifications in cellular growth and chromosome instability, which could promote lymphomagenesis over time.

Estimation of radiation doses on lymphocytes and their progenitors after ingestion of strontium-89,90

In radiobiology circulating T-lymphocytes are used as “natural biodosimeters” since the frequency of chromosomal aberrations that occur in them after radiation exposure is proportional to the accumulated dose. In addition, stable chromosomal aberrations (translocations) are detected in them years and decades after radiation exposure. Estimation of doses to circulating lymphocytes requires consideration of two dose components: the dose accumulated by the lymphocyte precursors (progenitors) in the red bone marrow; and dose accumulated by the lymphocytes in the lymphoid organs/tissues during circulation. A recently created model of T-lymphocyte exposure takes into account all these dose components, as well as the age-dependent dynamics of T-lymphocytes. The use of a model approach is especially important in assessing doses from osteotropic beta emitters (89,90Sr). They accumulate in the bone and locally expose predominately bone marrow. The dose to other lymphoid organs and tissues is much lower. The objective of this study is to evaluate the conversion factors from ingested 89,90Sr to the cumulative dose to circulating T-lymphocytes and their progenitors (DCL). For calculations, the previously developed model of T-lymphocyte exposure and new dose coefficients for the red bone marrow, estimated on the basis of a sex-and-age-dependent biokinetic model and a new dosimetric model of the human skeleton were used. As a result, the DCL values were evaluated for the first time. The age at the time of 89,90Sr intake varied from a newborn to 35 years, the age of T-lymphocyte examination (blood sampling age) was up to 75 years. The maximum values of DCL for both 90Sr and 89Sr were typical of children in the first years of life. It has been shown that doses to circulating T-lymphocytes from these radionuclides are lower than those to bone marrow, but are significantly higher than doses to other lymphoid tissues. The effect of sex on DCL is manifested for children 10 years of age and older. The area of DCL application covers the population of radioactively contaminated territories (the Urals region, the zone of the Chernobyl accident), as well as personnel of the nuclear industry enterprises.

Fluorescence in situ hybridization analysis of chromosomal aberrations in mouse splenocytes at one- and two-months after total body exposure to iron-56 (Fe) ion particles or X-rays.

High atomic number and energy (HZE) particles such as iron-56 (Fe) ions are a major contributor to health risks in long-term manned space exploration. The aim of this study is to understand radiation-induced differential genotoxic effects between HZE particles and low linear energy transfer (LET) photons. C57BL/6J Jms female mice of 8 weeks old were exposed to total body irradiation of accelerated Fe-particles with a dose ranging from 0.1 to 3.0Gy or of X-rays with a dose ranging from 0.1 to 5.0Gy. Chromosomal aberrations (CAs) in splenocytes were examined by fluorescence in situ hybridization at 1- and 2-months after exposure. Clonal expansions of cells with CAs were found to be induced only by X-rays but not by Fe-particles. Dose-dependent increase in the frequencies of stable-type CAs was observed at 1- as well as 2-months after exposure to both radiation types. The frequencies of stable-type CAs in average were much higher in mice exposed to X-rays than those to Fe-particles and did not change significantly between 1- and 2-months after exposure to both radiation types. On the other hand, the frequencies of unstable-type CAs induced by X-rays and Fe-particles were not much different, and they appeared to decrease with time from 1- to 2-months after exposure. These results suggested that larger fraction of stable-type CAs induced by Fe-particles might be non-transmissible than those by X-rays because of some associating lethal alterations on themselves or on other chromosomes in the same cells and that these cells might be removed by 1-month after Fe-TBI. We also demonstrated that exposure to Fe-particles induced insertions at relatively higher frequency to other stable-type CAs than X-rays. Our findings suggest that insertions can be used as indicators of past exposure to high-LET particle radiation.

THE LANDSCAPE OF CHROMOSOMAL ABERRATIONS IN 10,000 EMBRYOS DERIVED FROM FRESH DONOR OOCYTES

Information on chromosomal aberration rates in embryos derived from a young population, such as egg donors, is limited. PGT-A is the best predictive tool for embryo selection. It is most often offered to patients with advanced age, but with contradicting recommendations in younger patients. The objective was to evaluate the type and frequency of chromosomal aberrations in embryos derived from fresh young donor oocytes detected at NGS resolution of 10Mb and >30% mosaicism.

Metal chelating and anti-radical activity of Salvia officinalis in the ameliorative effects against uranium toxicity

Uranium is a highly radioactive heavy metal that is toxic to living things. In this study, physiological, cytogenetic, biochemical and anatomical toxicity caused by uranium and the protective role of sage (Salvia officinalis L.) leaf extract against this toxicity were investigated with the help of Allium test. Germination percentage, root length, weight gain, mitotic index (MI), micronucleus (MN) formation, chromosomal aberrations (CAs), superoxide dismutase (SOD) and catalase (CAT) enzyme activities, malondialdehyde (MDA) levels and changes in root meristem cells were used as indicators of toxicity. In the experimental stage, a total of six groups, one of which was the control, were formed. Group I was treated with tap water, while group II and III were treated only with sage (190 mg/L and 380 mg/L). Groups IV, V and VI were germinated with uranyl acetate dihydrate (0.1 mg/mL), uranyl acetate dihydrate + 190 mg/L sage and uranyl acetate dihydrate + 380 mg/L sage, respectively. Allium cepa L. bulbs of each group were germinated for 72 h, and at the end of the period, routine preparation techniques were applied and physiological, cytogenetic, biochemical and anatomical analyzes were performed. As a result, uranium application caused a significant decrease (p < 0.05) in all physiological parameters and MI values. MN, CAs numbers, SOD and CAT enzyme activities and MDA levels increased significantly (p < 0.05) with uranium application. Uranium promoted CAs in the root tip cells in the form of fragment, vagrant chromosome, sticky chromosome, bridge and unequal distribution of chromatin. In addition, it caused anatomical damages such as epidermis cell damage, cortex cell damage and flattened cell nucleus in root tip meristem cells. Sage application together with uranium caused significant (p < 0.05) increases in physiological parameters and MI values and significant decreases in MN, CAs, SOD and CAT activities and MDA levels. In addition, the application of sage resulted in improvement in the severity of anatomical damages induced by uranium. It was determined that the protective role of sage observed for all parameters investigated was even more pronounced at dose of 380 mg/L. The protective role of sage against uranium toxicity is related to its antioxidant activity, and sage has 82.8% metal chelating and 72.9% DPPH removal activity. As a result, uranyl acetate exhibited versatile toxicity in A. cepa, caused cytotoxicity by decreasing the MI rate, and genotoxicity by increasing the frequencies of MN and CAs. And also, Sage acted as a toxicity-reducing agent by displaying a dose-dependent protective role against the toxic effects induced by uranyl acetate.

EXPERIMENTAL STUDIES AT THE IES ON THE BIOLOGICAL EFFECTS OF CHRONIC LOW DOSE-RATE RADIATION EXPOSURE IN MICE.

Research in the Department of Radiobiology at the Institute for Environmental Sciences (IES) has focused mainly on the biological effects of long-term low dose-rate radiation exposure on mice since its establishment 30y ago. The IES has exposed thousands of mice of various strains, to gamma-rays, mostly chronically, at low dose-rates of 0.05, 1, 20 or 100mGy/d, at medium dose-rates of 200 or 400mGy/d or at acute high dose-rates of 0.7-0.9Gy/min. The dose-rate 0.05mGy/d is comparable with the dose limit for radiation workers of 100mSv/5y. The results will be presented based on the parameters examined at various endpoints such as life span, neoplasm (cancer incidence), chromosome aberrations frequencies, alterations in mRNA levels, tumour transplantability and developmental abnormalities after in utero exposures. The results from research collaborations with universities and institutions both domestic (within Japan) and international will be presented. Lastly, an outline of experiments (e.g. juvenile exposure, low dose tritium exposures) and projects (e.g. radiobiology archives) currently in progress and future research perspectives will be described.

Fisetin induces DNA double-strand break and interferes with the repair of radiation-induced damage to radiosensitize triple negative breast cancer cells

BackgroundTriple-negative breast cancer (TNBC) is associated with aggressiveness and a poor prognosis. Besides surgery, radiotherapy serves as the major treatment modality for TNBC. However, response to radiotherapy is limited in many patients, most likely because of DNA damage response (DDR) signaling mediated radioresistance. Y-box binding protein-1 (YB-1) is a multifunctional protein that regulates the cancer hallmarks among them resisting to radiotherapy-induced cell death. Fisetin, is a plant flavonol of the flavonoid family of plant polyphenols that has anticancer properties, partially through inhibition of p90 ribosomal S6 kinase (RSK)-mediated YB-1 phosphorylation. The combination of fisetin with radiotherapy has not yet been investigated.MethodsActivation status of the RSK signaling pathway in total cell lysate and in the subcellular fractions was analyzed by Western blotting. Standard clonogenic assay was applied to test post-irradiation cell survival. γH2AX foci assay and 3 color fluorescence in situ hybridization analyses were performed to study frequency of double-strand breaks (DSB) and chromosomal aberrations, respectively. The underlying repair pathways targeted by fisetin were studied in cells expressing genomically integrated reporter constructs for the DSB repair pathways via quantifying the expression of green fluorescence protein by flow cytometry. Flow cytometric quantification of sub-G1 cells and the protein expression of LC3-II were employed to measure apoptosis and autophagy, respectively. Kinase array and phosphoproteomics were performed to study the effect of fisetin on DDR response signaling.ResultsWe showed that the effect of fisetin on YB-1 phosphorylation in TNBC cells is comparable to the effect of the RSK pharmacological inhibitors. Similar to ionizing radiation (IR), fisetin induces DSB. Additionally, fisetin impairs repair of IR-induced DSB through suppressing the classical non-homologous end-joining and homologous recombination repair pathways, leading to chromosomal aberration as tested by metaphase analysis. Effect of fisetin on DSB repair was partially dependent on YB-1 expression. Phosphoproteomic analysis revealed that fisetin inhibits DDR signaling, which leads to radiosensitization in TNBC cells, as shown in combination with single dose or fractionated doses irradiation.ConclusionFisetin acts as a DSB-inducing agent and simultaneously inhibits repair of IR-induced DSB. Thus, fisetin may serve as an effective therapeutic strategy to improve TNBC radiotherapy outcome.

GC-MS and HPLC supported phytochemical analysis of watercress and the protective role against paraben toxicity.

In this study, the phytochemical content of Nasturtium officinale R. Br. (watercress) leaf extract (Noex) and its protective effects against paraben toxicity were investigated. GC-MS and HPLC analyses were performed to determine the phytochemical content. Paraben toxicity and protective properties of Noex were investigated with the Allium test, and 6 different groups were formed for this purpose. Toxicity in each group was investigated by using physiological, cytogenetic, biochemical, and anatomical parameters. DNA-paraben interaction was investigated with spectroscopic analysis for the genotoxicity mechanism. As a result of the study, paraben (500mM) caused a regression in the physiological parameters related to germination in Allium cepa L. bulbs. Paraben caused a 43.3% reduction in mitotic index (MI) rates compared to control, which is likely the reason for the decrease in germination-related parameters. With the application of paraben in root tip cells, the frequency of micronucleus (MN) and chromosomal aberrations (CAs) increased and a high genotoxic effect was observed. Paraben promoted CAs such as fragment, sticky chromosome, bridge, unequal distribution of chromatin, and irregular mitosis. It also caused anatomical damage in the form of epidermis cell damage, flattened cell nucleus, cortex cell damage, cortex cell walls thickening, and unclear vascular tissue in root tip meristem cells. Paraben-DNA interaction was caused by bathochromic and hypochromic shifts in the UV spectrum of DNA, indicating the intercalation mode of interaction. Paraben also caused an increase in malondialdehyde (MDA) levels, a decrease in glutathione (GSH) levels, and abnormalities in antioxidant enzyme levels (superoxide dismutase = SOD and catalase = CAT), thereby disrupting the antioxidant/oxidant dynamics in the cell. The basis of physiological, cytological, and genetic abnormalities was attributed to the oxidative stress in the cell. Administration of Noex produced a dose-dependent incremental improvement in paraben-induced abnormalities. The increase in GSH levels and the decrease in MDA levels observed as a result of the Noex application contributed to the restoration of antioxidant/oxidant balance, and this improvement was also reflected in other parameters. Application of 200mg/L Noex provided a 24.2% improvement in the MI rate reduced by paraben, and accordingly, an increase in germination parameters was observed. Similarly, the frequencies of MN and CAs, which are signs of genotoxicity, decreased with the Noex application. As a result of the phytochemical analysis of Noex with HPLC and GC-MS, the presence of strong antioxidant and antimutagenic substances such as rutin, coumaric acid, ferrulic acid, L-serine, L-proline, and phytol were determined in Noex structure. The curative effects of Noex against paraben toxicity can be attributed to these active ingredients.

Molecular docking and spectral shift supported toxicity profile of metaldehyde mollucide and the toxicity-reducing effects of bitter melon extract

Excessive use of metaldehyde to combat mollusks directly or indirectly endangers non-targeted organisms. The present study aimed to reveal the antitoxic potential of bitter melon (Momordica charantia L.) extract (BME) against metaldehyde-related toxicity in Allium cepa L. The experimental groups formed using A. cepa bulbs were exposed to aqueous solutions containing 350 mg/L BME, 700 mg/L BME, 200 mg/L metaldehyde, 200 mg/L metaldehyde +350 mg/L BME and 200 mg/L metaldehyde +700 mg/L BME, respectively. The bulbs in the control group dipped in tap water. Metaldehyde suppressed growth with respect to germination ratio, root elongation and weight gain parameters. In metaldehyde-administered group, mitotic index (MI) was reduced, while the frequencies of micronucleus (MN) and chromosomal aberrations (CAs) increased. Metaldehyde promoted CAs such as sticky chromosomes, vagrant chromosome, fragment, unequal distribution of chromatin, reverse polarization, bridge and multipolar anaphase in root tip meristem cells. Spectral shift and molecular docking confirmed the genotoxic effect of metaldehyde resulting from DNA-metaldehyde interaction. The DNA damage in root meristems was revealed using the Comet Assay. Metaldehyde stress provoked oxidative stress. Activities superoxide dismutase (SOD) and catalase (CAT) enzymes along with level of malondialdehyde (MDA) accumulation accelerated. In roots treated with metaldehyde, epidermis cell damage, flattened cell nucleus, cortex cell damage and cortex cell wall thickening were observed as meristematic cell damage. BME attenuated metaldehyde-induced toxicity in a dose-dependent manner. This study demonstrated the mitigative potential of plant derived BME with no-to-low side effects against hazardous chemicals including metaldehyde. Nature is the most valuable weapon against toxicity from pollutants. Therefore, the protective potential of BME against other harmful agents should be screened.

Screening of natural surface waters of the Almaty region of the Republic of Kazakhstan for toxic and mutagenic activity

Natural aquatic ecosystems are a habitat for many organisms, a source of drinking water, and a resource for human economic activity. However, natural surface waters have been subjected to intense anthropogenic pressure in recent decades. The current study was dedicated to investigating genotoxic potential in 15 rivers and 2 lakes of Almaty agglomeration (Kazakhstan) using a battery of bioassays. Non-diluted surface water samples were tested for mutagenic potential using Lux-based bacterial biosensors and a chromosome aberration test on Hordeum vulgare and Mus musculus. The studies involved lux-biosensors pRecA-lux, pColD-lux, pSoxS-lux, pKatG-lux did not find any genotoxic and oxidative effects. However, the mutagenicity of the studied water samples was detected by using plant and animal tests (Hordeum vulgare and Mus musculus). Mutagenic (increase in the frequency of chromosomal aberrations) activity of the water samples was observed. Among 17 sample collection points, surface waters of 12 were considered to possess mutagenic activity when tested on Hordeum vulgare. The results of the cytogenetic assay on mice bone marrow are alarming, as the survey proposed the strong genotoxic potential of water for mammals. Among 17 sample collection points, surface waters of 7 were considered to possess mutagenic activity when tested on Mus musculus. This comprehensive study indicates that the contamination of the surface natural waters poses a threat to river dwellers and the human population in the rivers and lakes areas.

Chromosome aberrations, micronucleus frequency, and catalase concentration in a population chronically exposed to high levels of radon

Purpose To deepen our knowledge on the effects of high levels of indoor radon exposure, we assessed the frequencies of unstable and stable chromosome aberrations and micronucleus (MN), as well as the concentration of an endogenous antioxidant (catalase, CAT), in blood samples of individuals chronically exposed to high indoor radon concentrations in Indonesia (Tande-Tande sub-village, Mamuju, West Sulawesi). Moreover, we also investigated the occurrence of a radio-adaptive response (RAR) in Tande-Tande sub-village inhabitants using the G2 MN assay. Materials and Methods The frequencies of dicentric (DC), acentric (AF), ring (R), and translocation (Tr) chromosomes in Tande-Tande inhabitants were compared to those in people living in a reference area with low levels of indoor radon levels (Topoyo village, Indonesia). The number of MN per 1000 binucleated cells (BNC) and CAT concentration per total protein was quantified and compared between groups. Lastly, we irradiated (2 Gy) phytohemagglutinin-stimulated samples in vitro and measured the frequency of MN to verify the occurrence of a RAR in Tande-Tande sub-village inhabitants. Results and Conclusion The frequencies of DC, AF, and Tr did not differ between Tande-Tande inhabitants and control subjects (p = 0.350, 0.521, 0.597). The frequency of MN in Tande-Tande inhabitants was significantly lower than that in the control group (p = 0.006). Similarly, CAT concentration in Tande-Tande inhabitants was also significantly lower than that in the control population (p < 0.001). Significant negative correlations were identified for MN number and CAT concentration versus indoor radon concentration, annual effective dose, or cumulative dose both within groups and when all data were analyzed together. Our findings indicate that, despite the high indoor radon levels, Tande-Tande inhabitants are not under oxidative stress, since this group had lower CAT concentration and MN frequency than those in the control group. The negative correlation between MN frequency and indoor radon concentration, annual effective dose, and cumulative dose suggests the occurrence of an RAR phenomenon in Tande-Tande sub-village inhabitants. This interpretation is also supported by the results of the G2 MN assay, which revealed lower MN frequencies after in vitro irradiation of samples from Tande-Tande sub-village inhabitants than those in samples from the control group (p = 0.0069, for cumulative MN frequency; p = 0.0146, for radiation-induced MN only).

Chromosomal Aberrations in Large Japanese Field Mice (Apodemus speciosus) Captured in Various Periods after Fukushima Daiichi Nuclear Power Plant Accident.

After the Fukushima Daiichi Nuclear Power Plant accident, we studied the chromosomal aberrations (dicentrics and translocations) in the splenic lymphocytes of wild mice inhabiting Fukushima prefecture. Here, we report the frequencies of chromosomal aberrations in large Japanese field mice (Apodemus speciosus) captured from 2012 to 2016 in a heavily contaminated area. The chromosomal aberrations were detected using newly developed 4-color FISH (fluorescence in situ hybridization) with A. speciosus chromosome 1-, 3-, 4- and 5-specific painting probes. The frequencies of chromosomal aberrations in mice captured in July 2012 and October 2014 were significantly higher than that in the mice inhabiting the non-contaminated control area; however, the frequency of chromosomal aberrations in mice captured in January 2016 was not. The frequency of chromosomal aberrations in individual mice tended to increase with certain dose rates and accumulated doses. Regression tree analyses suggested increasing chromosomal aberration rate in mice exposed to chronic radiation at dose rates of more than 1.1 mGy day-1 and at accumulated doses of more than 200 mGy. It is concluded that ambient dose rates in the most severely contaminated area of Fukushima prefecture and radiation doses to wild mice inhabiting this area decrease with time; consequently, chromosomal aberrations induced by radiation have not been detected 5 years after the accident.

O003 Radiation-related chromosomal aberrations observed in high volume endovascular operators performing X-ray guided surgery

Abstract Introduction The biological effects of chronic, low dose radiation, to which operators performing fluoroscopy-guided procedures are exposed, are unknown. We have previously demonstrated acute DNA damage/repair in lymphocytes from operators performing fluoroscopy-guided endovascular aneurysm repair (EVAR), but these markers normalised after 24 hours and did not inform on the residual accumulated effects of chronic radiation exposure. In the present study cytogenetic techniques were used to examine for chromosomal aberrations in endovascular operators. Methods Peripheral blood lymphocytes were isolated from high volume endovascular operators performing EVAR and age-matched radiation naïve general surgeons as controls. Giemsa staining was used to visualise the full complement of chromosomes and all dicentrics, where 2 centromeres are present in a single chromosome, were identified. The genome was analysed for abnormal exchanges of genetic material between chromosomes using multiplex fluorescence in situ hybridisation (mFISH). Results Lymphocytes from 18 operators (12 exposed, 6 controls) were analysed. A higher frequency of dicentric chromosomes were found in exposed operators compared with controls (0.0011 vs 0.0004, respectively, P=0.002) after examining 54,000 lymphocytes. Twice as many complex chromosome rearrangements were seen in endovascular operators compared with controls (0.48% vs 0.24%). Aneuploidy, the abnormal loss of chromosomes, was more frequent in endovascular operators with a median difference of 0.35 per chromosome (P=0.004). Conclusion We have found a higher frequency of chromosomal aberrations in endovascular operators compared with radiation naïve colleagues. This justifies further individual biological profiling for genomic instability and personalised radiation risk assessment. Take-home message Radiation-related DNA damage occurs in endovascular operators despite current radiation protection measures. Biological dosimetry could be a useful tool, allowing personalised risk assessment.