SOX9 is targeted for proteasomal degradation by the E3 ligase FBW7 in response to DNA damage

PubMed Central

Hong, Xuehui; Liu, Wenyu; Song, Ruipeng; Shah, Jamie J.; Feng, Xing; Tsang, Chi Kwan; Morgan, Katherine M.; Bunting, Samuel F.; Inuzuka, Hiroyuki; Zheng, X. F. Steven; Shen, Zhiyuan; Sabaawy, Hatem E.; Liu, LianXin; Pine, Sharon R.

2016-01-01

SOX9 encodes a transcription factor that governs cell fate specification throughout development and tissue homeostasis. Elevated SOX9 is implicated in the genesis and progression of human tumors by increasing cell proliferation and epithelial-mesenchymal transition. We found that in response to UV irradiation or genotoxic chemotherapeutics, SOX9 is actively degraded in various cancer types and in normal epithelial cells, through a pathway independent of p53, ATM, ATR and DNA-PK. SOX9 is phosphorylated by GSK3β, facilitating the binding of SOX9 to the F-box protein FBW7α, an E3 ligase that functions in the DNA damage response pathway. The binding of FBW7α to the SOX9 K2 domain at T236-T240 targets SOX9 for subsequent ubiquitination and proteasomal destruction. Exogenous overexpression of SOX9 after genotoxic stress increases cell survival. Our findings reveal a novel regulatory mechanism for SOX9 stability and uncover a unique function of SOX9 in the cellular response to DNA damage. This new mechanism underlying a FBW7-SOX9 axis in cancer could have implications in therapy resistance. PMID:27566146

Glioma Cell Death Induced by Irradiation or Alkylating Agent Chemotherapy Is Independent of the Intrinsic Ceramide Pathway

PubMed Central

Gramatzki, Dorothee; Herrmann, Caroline; Happold, Caroline; Becker, Katrin Anne; Gulbins, Erich; Weller, Michael; Tabatabai, Ghazaleh

2013-01-01

Background/Aims Resistance to genotoxic therapy is a characteristic feature of glioma cells. Acid sphingomyelinase (ASM) hydrolyzes sphingomyelin to ceramide and glucosylceramide synthase (GCS) catalyzes ceramide metabolism. Increased ceramide levels have been suggested to enhance chemotherapy-induced death of cancer cells. Methods Microarray and clinical data for ASM and GCS in astrocytomas WHO grade II–IV were acquired from the Rembrandt database. Moreover, the glioblastoma database of the Cancer Genome Atlas network (TCGA) was used for survival data of glioblastoma patients. For in vitro studies, increases in ceramide levels were achieved either by ASM overexpression or by the GCS inhibitor DL-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP) in human glioma cell lines. Combinations of alkylating chemotherapy or irradiation and ASM overexpression, PPMP or exogenous ceramide were applied in parental cells. The anti-glioma effects were investigated by assessing proliferation, metabolic activity, viability and clonogenicity. Finally, viability and clonogenicity were assessed in temozolomide (TMZ)-resistant cells upon treatment with PPMP, exogenous ceramide, alkylating chemotherapy, irradiation or their combinations. Results Interrogations from the Rembrandt and TCGA database showed a better survival of glioblastoma patients with low expression of ASM or GCS. ASM overexpression or PPMP treatment alone led to ceramide accumulation but did not enhance the anti-glioma activity of alkylating chemotherapy or irradiation. PPMP or exogenous ceramide induced acute cytotoxicity in glioblastoma cells. Combined treatments with chemotherapy or irradiation led to additive, but not synergistic effects. Finally, no synergy was found when TMZ-resistant cells were treated with exogenous ceramide or PPMP alone or in combination with TMZ or irradiation. Conclusion Modulation of intrinsic glioma cell ceramide levels by ASM overexpression or GCS inhibition does not enhance the anti-glioma activity of alkylating chemotherapy or irradiation. PMID:23667632

Chromatin relaxation-mediated induction of p19INK4d increases the ability of cells to repair damaged DNA.

PubMed

Ogara, María F; Sirkin, Pablo F; Carcagno, Abel L; Marazita, Mariela C; Sonzogni, Silvina V; Ceruti, Julieta M; Cánepa, Eduardo T

2013-01-01

The maintenance of genomic integrity is of main importance to the survival and health of organisms which are continuously exposed to genotoxic stress. Cells respond to DNA damage by activating survival pathways consisting of cell cycle checkpoints and repair mechanisms. However, the signal that triggers the DNA damage response is not necessarily a direct detection of the primary DNA lesion. In fact, chromatin defects may serve as initiating signals to activate those mechanisms. If the modulation of chromatin structure could initiate a checkpoint response in a direct manner, this supposes the existence of specific chromatin sensors. p19INK4d, a member of the INK4 cell cycle inhibitors, plays a crucial role in regulating genomic stability and cell viability by enhancing DNA repair. Its expression is induced in cells injured by one of several genotoxic treatments like cis-platin, UV light or neocarzinostatin. Nevertheless, when exogenous DNA damaged molecules are introduced into the cell, this induction is not observed. Here, we show that p19INK4d is enhanced after chromatin relaxation even in the absence of DNA damage. This induction was shown to depend upon ATM/ATR, Chk1/Chk2 and E2F activity, as is the case of p19INK4d induction by endogenous DNA damage. Interestingly, p19INK4d improves DNA repair when the genotoxic damage is caused in a relaxed-chromatin context. These results suggest that changes in chromatin structure, and not DNA damage itself, is the actual trigger of p19INK4d induction. We propose that, in addition to its role as a cell cycle inhibitor, p19INK4d could participate in a signaling network directed to detecting and eventually responding to chromatin anomalies.

Oxidative DNA damage caused by inflammation may link to stress-induced non-targeted effects

PubMed Central

Sprung, Carl N.; Ivashkevich, Alesia; Forrester, Helen B.; Redon, Christophe E.; Georgakilas, Alexandros; Martin, Olga A.

2013-01-01

A spectrum of radiation-induced non-targeted effects has been reported during the last two decades since Nagasawa and Little first described a phenomenon in cultured cells that was later called the “bystander effect”. These non-targeted effects include radiotherapy-related abscopal effects, where changes in organs or tissues occur distant from the irradiated region. The spectrum of non-targeted effects continue to broaden over time and now embrace many types of exogenous and endogenous stressors that induce a systemic genotoxic response including a widely studied tumor microenvironment. Here we discuss processes and factors leading to DNA damage induction in non-targeted cells and tissues and highlight similarities in the regulation of systemic effects caused by different stressors. PMID:24041866

A quantum chemical study of the reactivity of acetaminophen (paracetamol) toxic metabolite N-acetyl-p-benzoquinone imine with deoxyguanosine and glutathione.

PubMed

Klopčič, Ivana; Poberžnik, Matic; Mavri, Janez; Dolenc, Marija Sollner

2015-12-05

Acetaminophen (APAP) forms some reactive metabolites that can react with DNA. APAP is a potentially genotoxic drug and is classified as a Group 3 drug according to International Agency for Research on Cancer (IARC). One of the possible mechanisms of APAP genotoxicity after long term of use is that its reactive quinone imine (QI) metabolite of acetaminophen (NAPQI), can chemically react with DNA after glutathione (GSH) depletion. A quantum chemical study of the reactions between the NAPQI and deoxyguanosine (dG) or GSH was performed. Activation energies (ΔG(ǂ)) for the reactions associated with the 1, 4-Michael addition were calculated on the M062X/6-311++G (d,p) level of theory. We modeled the reaction with dG as a multi-step process. The first step is rate-limiting (ΔG(ǂ) = 26.7 kcal/mol) and consists of formation of a C-N bond between the C3 atom of the QI moiety and the N7 atom of dG. The second step involves proton transfer from the C3 moiety to the nitrogen atom of the QI with ΔG(ǂ) of 13.8 kcal/mol. The depurination reaction that follows has a ΔG(ǂ) of 25.7 kcal/mol. The calculated ΔG(ǂ) for the nucleophilic attack of the deprotonated S atom of GSH on the C3 atom of the NAPQI is 12.9 kcal/mol. Therefore, the QI will react with GSH much faster than with DNA. Our study gives mechanistic insight into the genotoxicity of the APAP metabolite and will be useful for estimating the genotoxic potential of existing drugs with a QI moiety. Our results show that clinical application of APAP is safe, while in the case of severely depleted GSH levels APAP should be administered with caution. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Melittin induced cytogenetic damage, oxidative stress and changes in gene expression in human peripheral blood lymphocytes.

PubMed

Gajski, Goran; Domijan, Ana-Marija; Žegura, Bojana; Štern, Alja; Gerić, Marko; Novak Jovanović, Ivana; Vrhovac, Ivana; Madunić, Josip; Breljak, Davorka; Filipič, Metka; Garaj-Vrhovac, Vera

2016-02-01

Melittin (MEL) is the main constituent and principal toxin of bee venom. It is a small basic peptide, consisting of a known amino acid sequence, with powerful haemolytic activity. Since MEL is a nonspecific cytolytic peptide that attacks lipid membranes thus leading to toxicity, the presumption is that it could have significant therapeutic benefits. The aim was to evaluate the cyto/genotoxic effects of MEL in human peripheral blood lymphocytes (HPBLs) and the molecular mechanisms involved using a multi-biomarker approach. We found that MEL was cytotoxic for HPBLs in a dose- and time-dependent manner. It also induced morphological changes in the cell membrane, granulation and lysis of exposed cells. After treating HPBLs with non-cytotoxic concentrations of MEL, we observed increased DNA damage including oxidative DNA damage as well as increased formation of micronuclei and nuclear buds, and decreased lymphocyte proliferation determined by comet and micronucleus assays. The observed genotoxicity coincided with increased formation of reactive oxygen species, reduction of glutathione level, increased lipid peroxidation and phospholipase C activity, showing the induction of oxidative stress. MEL also modulated the expression of selected genes involved in DNA damage response (TP53, CDKN1A, GADD45α, MDM), oxidative stress (CAT, SOD1, GPX1, GSR and GCLC) and apoptosis (BAX, BCL-2, CAS-3 and CAS-7). Results indicate that MEL is genotoxic to HPBLs and provide evidence that oxidative stress is involved in its DNA damaging effects. MEL toxicity towards normal cells has to be considered if used for potential therapeutic purposes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cannabinoids inhibit neurodegeneration in models of multiple sclerosis.

PubMed

Pryce, Gareth; Ahmed, Zubair; Hankey, Deborah J R; Jackson, Samuel J; Croxford, J Ludovic; Pocock, Jennifer M; Ledent, Catherine; Petzold, Axel; Thompson, Alan J; Giovannoni, Gavin; Cuzner, M Louise; Baker, David

2003-10-01

Multiple sclerosis is increasingly being recognized as a neurodegenerative disease that is triggered by inflammatory attack of the CNS. As yet there is no satisfactory treatment. Using experimental allergic encephalo myelitis (EAE), an animal model of multiple sclerosis, we demonstrate that the cannabinoid system is neuroprotective during EAE. Mice deficient in the cannabinoid receptor CB1 tolerate inflammatory and excitotoxic insults poorly and develop substantial neurodegeneration following immune attack in EAE. In addition, exogenous CB1 agonists can provide significant neuroprotection from the consequences of inflammatory CNS disease in an experimental allergic uveitis model. Therefore, in addition to symptom management, cannabis may also slow the neurodegenerative processes that ultimately lead to chronic disability in multiple sclerosis and probably other diseases.

Expression of the human NAD(P)-metabolizing ectoenzyme CD38 compromises systemic acquired resistance in Arabidopsis.

PubMed

Zhang, Xudong; Mou, Zhonglin

2012-09-01

Plant systemic acquired resistance (SAR) is a long-lasting, broad-spectrum immune response that is mounted after primary pathogen infection. Although SAR has been extensively researched, the molecular mechanisms underlying its activation have not been completely understood. We have previously shown that the electron carrier NAD(P) leaks into the plant extracellular compartment upon pathogen attack and that exogenous NAD(P) activates defense gene expression and disease resistance in local treated leaves, suggesting that extracellular NAD(P) [eNAD(P)] might function as a signal molecule activating plant immune responses. To further establish the function of eNAD(P) in plant immunity, we tested the effect of exogenous NAD(P) on resistance gene-mediated hypersensitive response (HR) and SAR. We found that exogenous NAD(P) completely suppresses HR-mediated cell death but does not affect HR-mediated disease resistance. Local application of exogenous NAD(P) is unable to induce SAR in distal tissues, indicating that eNAD(P) is not a sufficient signal for SAR activation. Using transgenic Arabidopsis plants expressing the human NAD(P)-metabolizing ectoenzyme CD38, we demonstrated that altering eNAD(P) concentration or signaling compromises biological induction of SAR. This result suggests that eNAD(P) may play a critical signaling role in activation of SAR.

Translational approach to the pathophysiology of panic disorder: Focus on serotonin and endogenous opioids.

PubMed

Graeff, Frederico G

2017-05-01

Panic patients experience recurrent panic attacks. Two main neurochemical hypotheses have been proposed to explain this vulnerability. The first suggests that panic patients have deficient serotonergic inhibition of neurons localized in the dorsal periaqueductal gray matter of the midbrain that organizes defensive reactions to cope with proximal threats as well as of sympathomotor control areas of the rostral ventrolateral medulla that generate neurovegetative symptoms of the panic attack. The second proposes that endogenous opioids buffer panic attacks in normal subjects, and their deficit results in heightened sensitivity to suffocation and separation anxiety in panic patients. Experimental results obtained in rat models of panic indicate that serotonin interacts synergistically with endogenous opioids in the dorsal periaqueductal gray through 5-HT1A and μ-opioid receptors to inhibit proximal defense and, supposedly, panic attacks. These findings allow reconciliation of the serotonergic and opioidergic hypotheses of panic pathophysiology. They also indicate that endogenous opioids are likely to participate in the panicolytic action of antidepressants and suggest that exogenous opioids may be useful for treating panic patients resistant to conventional pharmacotherapy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chromatin Relaxation-Mediated Induction of p19INK4d Increases the Ability of Cells to Repair Damaged DNA

PubMed Central

Carcagno, Abel L.; Marazita, Mariela C.; Sonzogni, Silvina V.; Ceruti, Julieta M.; Cánepa, Eduardo T.

2013-01-01

The maintenance of genomic integrity is of main importance to the survival and health of organisms which are continuously exposed to genotoxic stress. Cells respond to DNA damage by activating survival pathways consisting of cell cycle checkpoints and repair mechanisms. However, the signal that triggers the DNA damage response is not necessarily a direct detection of the primary DNA lesion. In fact, chromatin defects may serve as initiating signals to activate those mechanisms. If the modulation of chromatin structure could initiate a checkpoint response in a direct manner, this supposes the existence of specific chromatin sensors. p19INK4d, a member of the INK4 cell cycle inhibitors, plays a crucial role in regulating genomic stability and cell viability by enhancing DNA repair. Its expression is induced in cells injured by one of several genotoxic treatments like cis-platin, UV light or neocarzinostatin. Nevertheless, when exogenous DNA damaged molecules are introduced into the cell, this induction is not observed. Here, we show that p19INK4d is enhanced after chromatin relaxation even in the absence of DNA damage. This induction was shown to depend upon ATM/ATR, Chk1/Chk2 and E2F activity, as is the case of p19INK4d induction by endogenous DNA damage. Interestingly, p19INK4d improves DNA repair when the genotoxic damage is caused in a relaxed-chromatin context. These results suggest that changes in chromatin structure, and not DNA damage itself, is the actual trigger of p19INK4d induction. We propose that, in addition to its role as a cell cycle inhibitor, p19INK4d could participate in a signaling network directed to detecting and eventually responding to chromatin anomalies. PMID:23593412

Safety and performance analysis of acriflavine and methylene blue for in vivo imaging of precancerous lesions using fibered confocal fluorescence microscopy (FCFM): an experimental study.

PubMed

Obstoy, Bérengère; Salaun, Mathieu; Veresezan, Liana; Sesboüé, Richard; Bohn, Pierre; Boland, François-Xavier; Thiberville, Luc

2015-03-31

Fibered confocal fluorescence microscopy (FCFM) allows in vivo investigation of pulmonary microstructures. However, the bronchial epithelium can only be imaged using exogenous fluorophores. The objective of this study is to compare methylene blue (MB) and acriflavine genotoxicity and to assess FCFM performance for in vivo imaging of precancerous lesions. Genotoxicity was assessed using the comet assay on both cultured human lymphocytes and NCI-H460 cells, which had been exposed to MB or acriflavine before being illuminated at 660 or 488 nm, respectively. FCFM was performed on precancerous lesions in the hamster cheek pouch model, following topical application of the fluorophores. FCFM data were analyzed according to histology. No genotoxicity was found using 0.01% (w/v) MB after illumination at 660 nm for 2 and 15 min (5 mW). Acriflavine exposure (0.025%) led to DNA damages, increasing from 2 to 15 min of light exposure at 448 nm in both lymphocytes (83.4 to 88%, p = 0.021) and NCI H460 cell populations (79.9 to 84.6%, p = 0.045). In total, 11 invasive carcinoma, 24 reserve cell hyperplasia, and 17 dysplasia lesions were imaged using FCFM in vivo. With both fluorophores, the cellular density increased from hyperplasia to high-grade dysplasia (p < 0.05). With MB, the cellular diameter significantly decreased (48.9 to 13.9 μm) from hyperplasia to carcinoma (p < 0.05). In this model, a cut-off diameter of 30 μm enabled the diagnosis of high-grade lesions with a sensitivity of 94.7% and a specificity of 97%. Methylene blue can be used safely to image precancerous lesions in vivo. This study does not support the use of acriflavine in humans.

DNA Lesions Caused by ROS and RNOS: A Review of Interactions and Reactions Involving Guanine

NASA Astrophysics Data System (ADS)

Shukla, P. K.; Mishra, P. C.

DNA is constantly attacked by a large number of endogenous and exogenous reactive oxygen species (ROS), reactive nitrogen oxide species (RNOS), and alkylating agents which produce a wide variety of modifications of its constituents, particularly the bases. Some of these modifications (lesions) are hazardous to normal cell functioning, and are implicated in several lethal conditions including chronic inflammatory diseases, atherosclerosis, aging, mutation, cancer, and neurodegenerative disorders, such as the Alzheimer's and Parkinson's diseases.

Investigating the different mechanisms of genotoxic and non-genotoxic carcinogens by a gene set analysis.

PubMed

Lee, Won Jun; Kim, Sang Cheol; Lee, Seul Ji; Lee, Jeongmi; Park, Jeong Hill; Yu, Kyung-Sang; Lim, Johan; Kwon, Sung Won

2014-01-01

Based on the process of carcinogenesis, carcinogens are classified as either genotoxic or non-genotoxic. In contrast to non-genotoxic carcinogens, many genotoxic carcinogens have been reported to cause tumor in carcinogenic bioassays in animals. Thus evaluating the genotoxicity potential of chemicals is important to discriminate genotoxic from non-genotoxic carcinogens for health care and pharmaceutical industry safety. Additionally, investigating the difference between the mechanisms of genotoxic and non-genotoxic carcinogens could provide the foundation for a mechanism-based classification for unknown compounds. In this study, we investigated the gene expression of HepG2 cells treated with genotoxic or non-genotoxic carcinogens and compared their mechanisms of action. To enhance our understanding of the differences in the mechanisms of genotoxic and non-genotoxic carcinogens, we implemented a gene set analysis using 12 compounds for the training set (12, 24, 48 h) and validated significant gene sets using 22 compounds for the test set (24, 48 h). For a direct biological translation, we conducted a gene set analysis using Globaltest and selected significant gene sets. To validate the results, training and test compounds were predicted by the significant gene sets using a prediction analysis for microarrays (PAM). Finally, we obtained 6 gene sets, including sets enriched for genes involved in the adherens junction, bladder cancer, p53 signaling pathway, pathways in cancer, peroxisome and RNA degradation. Among the 6 gene sets, the bladder cancer and p53 signaling pathway sets were significant at 12, 24 and 48 h. We also found that the DDB2, RRM2B and GADD45A, genes related to the repair and damage prevention of DNA, were consistently up-regulated for genotoxic carcinogens. Our results suggest that a gene set analysis could provide a robust tool in the investigation of the different mechanisms of genotoxic and non-genotoxic carcinogens and construct a more detailed understanding of the perturbation of significant pathways.

Investigating the Different Mechanisms of Genotoxic and Non-Genotoxic Carcinogens by a Gene Set Analysis

PubMed Central

Lee, Won Jun; Kim, Sang Cheol; Lee, Seul Ji; Lee, Jeongmi; Park, Jeong Hill; Yu, Kyung-Sang; Lim, Johan; Kwon, Sung Won

2014-01-01

Based on the process of carcinogenesis, carcinogens are classified as either genotoxic or non-genotoxic. In contrast to non-genotoxic carcinogens, many genotoxic carcinogens have been reported to cause tumor in carcinogenic bioassays in animals. Thus evaluating the genotoxicity potential of chemicals is important to discriminate genotoxic from non-genotoxic carcinogens for health care and pharmaceutical industry safety. Additionally, investigating the difference between the mechanisms of genotoxic and non-genotoxic carcinogens could provide the foundation for a mechanism-based classification for unknown compounds. In this study, we investigated the gene expression of HepG2 cells treated with genotoxic or non-genotoxic carcinogens and compared their mechanisms of action. To enhance our understanding of the differences in the mechanisms of genotoxic and non-genotoxic carcinogens, we implemented a gene set analysis using 12 compounds for the training set (12, 24, 48 h) and validated significant gene sets using 22 compounds for the test set (24, 48 h). For a direct biological translation, we conducted a gene set analysis using Globaltest and selected significant gene sets. To validate the results, training and test compounds were predicted by the significant gene sets using a prediction analysis for microarrays (PAM). Finally, we obtained 6 gene sets, including sets enriched for genes involved in the adherens junction, bladder cancer, p53 signaling pathway, pathways in cancer, peroxisome and RNA degradation. Among the 6 gene sets, the bladder cancer and p53 signaling pathway sets were significant at 12, 24 and 48 h. We also found that the DDB2, RRM2B and GADD45A, genes related to the repair and damage prevention of DNA, were consistently up-regulated for genotoxic carcinogens. Our results suggest that a gene set analysis could provide a robust tool in the investigation of the different mechanisms of genotoxic and non-genotoxic carcinogens and construct a more detailed understanding of the perturbation of significant pathways. PMID:24497971

Autophagy and genomic integrity

PubMed Central

Vessoni, A T; Filippi-Chiela, E C; Menck, C FM; Lenz, G

2013-01-01

DNA lesions, constantly produced by endogenous and exogenous sources, activate the DNA damage response (DDR), which involves detection, signaling and repair of the damage. Autophagy, a lysosome-dependent degradation pathway that is activated by stressful situations such as starvation and oxidative stress, regulates cell fate after DNA damage and also has a pivotal role in the maintenance of nuclear and mitochondrial genomic integrity. Here, we review important evidence regarding the role played by autophagy in preventing genomic instability and tumorigenesis, as well as in micronuclei degradation. Several pathways governing autophagy activation after DNA injury and the influence of autophagy upon the processing of genomic lesions are also discussed herein. In this line, the mechanisms by which several proteins participate in both DDR and autophagy, and the importance of this crosstalk in cancer and neurodegeneration will be presented in an integrated fashion. At last, we present a hypothetical model of the role played by autophagy in dictating cell fate after genotoxic stress. PMID:23933813

Genotoxicity Assessment of Drinking Water Disinfection Byproducts by DNA Damage and Repair Pathway Profiling Analysis.

PubMed

Lan, Jiaqi; Rahman, Sheikh Mokhlesur; Gou, Na; Jiang, Tao; Plewa, Micheal J; Alshawabkeh, Akram; Gu, April Z

2018-06-05

Genotoxicity is considered a major concern for drinking water disinfection byproducts (DBPs). Of over 700 DBPs identified to date, only a small number has been assessed with limited information for DBP genotoxicity mechanism(s). In this study, we evaluated genotoxicity of 20 regulated and unregulated DBPs applying a quantitative toxicogenomics approach. We used GFP-fused yeast strains that examine protein expression profiling of 38 proteins indicative of all known DNA damage and repair pathways. The toxicogenomics assay detected genotoxicity potential of these DBPs that is consistent with conventional genotoxicity assays end points. Furthermore, the high-resolution, real-time pathway activation and protein expression profiling, in combination with clustering analysis, revealed molecular level details in the genotoxicity mechanisms among different DBPs and enabled classification of DBPs based on their distinct DNA damage effects and repair mechanisms. Oxidative DNA damage and base alkylation were confirmed to be the main molecular mechanisms of DBP genotoxicity. Initial exploration of QSAR modeling using moleular genotoxicity end points (PELI) suggested that genotoxicity of DBPs in this study was correlated with topological and quantum chemical descriptors. This study presents a toxicogenomics-based assay for fast and efficient mechanistic genotoxicity screening and assessment of a large number of DBPs. The results help to fill in the knowledge gap in the understanding of the molecular mechanisms of DBP genotoxicity.

The JaCVAM international validation study on the in vivo comet assay: Selection of test chemicals.

PubMed

Morita, Takeshi; Uno, Yoshifumi; Honma, Masamitsu; Kojima, Hajime; Hayashi, Makoto; Tice, Raymond R; Corvi, Raffaella; Schechtman, Leonard

2015-07-01

The Japanese Center for the Validation of Alternative Methods (JaCVAM) sponsored an international prevalidation and validation study of the in vivo rat alkaline pH comet assay. The main objective of the study was to assess the sensitivity and specificity of the assay for correctly identifying genotoxic carcinogens, as compared with the traditional rat liver unscheduled DNA synthesis assay. Based on existing carcinogenicity and genotoxicity data and chemical class information, 90 chemicals were identified as primary candidates for use in the validation study. From these 90 chemicals, 46 secondary candidates and then 40 final chemicals were selected based on a sufficiency of carcinogenic and genotoxic data, differences in chemical class or genotoxic or carcinogenic mode of action (MOA), availability, price, and ease of handling. These 40 chemicals included 19 genotoxic carcinogens, 6 genotoxic non-carcinogens, 7 non-genotoxic carcinogens and 8 non-genotoxic non-carcinogens. "Genotoxicity" was defined as positive in the Ames mutagenicity test or in one of the standard in vivo genotoxicity tests (primarily the erythrocyte micronucleus assay). These chemicals covered various chemicals classes, MOAs, and genotoxicity profiles and were considered to be suitable for the purpose of the validation study. General principles of chemical selection for validation studies are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

DNA double-strand break response in stem cells: mechanisms to maintain genomic integrity.

PubMed

Nagaria, Pratik; Robert, Carine; Rassool, Feyruz V

2013-02-01

Embryonic stem cells (ESCs) represent the point of origin of all cells in a given organism and must protect their genomes from both endogenous and exogenous genotoxic stress. DNA double-strand breaks (DSBs) are one of the most lethal forms of damage, and failure to adequately repair DSBs would not only compromise the ability of SCs to self-renew and differentiate, but will also lead to genomic instability and disease. Herein, we describe the mechanisms by which ESCs respond to DSB-inducing agents such as reactive oxygen species (ROS) and ionizing radiation, compared to somatic cells. We will also discuss whether the DSB response is fully reprogrammed in induced pluripotent stem cells (iPSCs) and the role of the DNA damage response (DDR) in the reprogramming of these cells. ESCs have distinct mechanisms to protect themselves against DSBs and oxidative stress compared to somatic cells. The response to damage and stress is crucial for the maintenance of self-renewal and differentiation capacity in SCs. iPSCs appear to reprogram some of the responses to genotoxic stress. However, it remains to be determined if iPSCs also retain some DDR characteristics of the somatic cells of origin. The mechanisms regulating the genomic integrity in ESCs and iPSCs are critical for its safe use in regenerative medicine and may shed light on the pathways and factors that maintain genomic stability, preventing diseases such as cancer. This article is part of a Special Issue entitled Biochemistry of Stem Cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Leydig Cell Aging and Hypogonadism

PubMed Central

Beattie, M.C.; Adekola, L.; Papadopoulos, V.; Chen, H.; Zirkin, B.R.

2015-01-01

Leydig cell testosterone (T) production is reduced with age, resulting in reduced serum T levels (hypogonadism). A number of cellular changes have been identified in the steroidogenic pathway of aged Leydig cells that are associated with reduced T formation, including reductions in luteinizing hormone (LH)-stimulated cAMP production, the cholesterol transport proteins steroidogenic acute regulatory (STAR) protein and translocator protein (TSPO), and downstream steroidogenic enzymes of the mitochondria and smooth endoplasmic reticulum. Many of the changes in steroid formation that characterize aged Leydig cells can be elicited by the experimental alteration of the redox environment of young cells, suggesting that changes in the intracellular redox balance may cause reduced T production. Hypogonadism is estimated to affect about 5 million American men, including both aged and young. This condition has been linked to mood changes, worsening cognition, fatigue, depression, decreased lean body mass, reduced bone mineral density, increased visceral fat, metabolic syndrome, decreased libido, and sexual dysfunction. Exogenous T administration is now used widely to elevate serum T levels in hypogonadal men and thus to treat symptoms of hypogonadism. However, recent evidence suggests that men who take exogenous T may face increased risk of stroke, heart attack, and prostate tumorigenesis. Moreover, it is well established that administered T can have suppressive effects on LH, resulting in lower Leydig cell T production, reduced intratesticular T concentration, and reduced spermatogenesis. This makes exogenous T administration inappropriate for men who wish to father children. There are promising new approaches to increase serum T by directly stimulating Leydig cell T production rather than by exogenous T therapy, thus potentially avoiding some of its negative consequences. PMID:25700847

Quantitative genotoxicity assays for analysis of medicinal plants: A systematic review.

PubMed

Sponchiado, Graziela; Adam, Mônica Lucia; Silva, Caroline Dadalt; Soley, Bruna Silva; de Mello-Sampayo, Cristina; Cabrini, Daniela Almeida; Correr, Cassyano Januário; Otuki, Michel Fleith

2016-02-03

Medicinal plants are known to contain numerous biologically active compounds, and although they have proven pharmacological properties, they can cause harm, including DNA damage. Review the literature to evaluate the genotoxicity risk of medicinal plants, explore the genotoxicity assays most used and compare these to the current legal requirements. A quantitative systematic review of the literature, using the keywords "medicinal plants", "genotoxicity" and "mutagenicity", was undertakenQ to identify the types of assays most used to assess genotoxicity, and to evaluate the genotoxicity potential of medicinal plant extracts. The database searches retrieved 2289 records, 458 of which met the inclusion criteria. Evaluation of the selected articles showed a total of 24 different assays used for an assessment of medicinal plant extract genotoxicity. More than a quarter of those studies (28.4%) reported positive results for genotoxicity. This review demonstrates that a range of genotoxicity assay methods are used to evaluate the genotoxicity potential of medicinal plant extracts. The most used methods are those recommended by regulatory agencies. However, based on the current findings, in order to conduct a thorough study concerning the possible genotoxic effects of a medicinal plant, we indicate that it is important always to include bacterial and mammalian tests, with at least one in vivo assay. Also, these tests should be capable of detecting outcomes that include mutation induction, clastogenic and aneugenic effects, and structural chromosome abnormalities. In addition, the considerable rate of positive results detected in this analysis further supports the relevance of assessing the genotoxicity potential of medicinal plants. Copyright © 2016. Published by Elsevier Ireland Ltd.

Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test.

PubMed

Nie, Xuebiao; Liu, Wenjun; Zhang, Liping; Liu, Qing

2017-06-01

The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV+chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl 2 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks. Copyright © 2016. Published by Elsevier B.V.

Genotoxic risk identification of soil contamination at a major industrialized city in northeast China by a combination of in vitro and in vivo bioassays.

PubMed

Xiao, Rui-Yang; Wang, Zijian; Wang, Chun-Xia; Yu, Guo; Zhu, Yong-Guan

2006-10-01

The present study evaluated the genotoxicity of field soils in the Tianjin area, one of the most industrialized contaminated areas in northeast China. The genotoxicity of organic extracts of 41 soils was assayed by an in vitro SOS/ umu bioassay with Salmonella typhimurium TA 1535/pSK 1002. From the 41 soil samples, 11 samples were selected to confirm the genotoxic effect by in vivo single-cell gel electrophoresis (comet assay) using earthworms (Eisenia fetida). The results obtained demonstrated that, in the in vitro assay, genotoxicity expressed as induction ratios (IR) ranged from 1.00 to 4.60, and in the in vivo assay, the genotoxicity expressed as tail moment (TM) varied from 14.6 to 57.8 microm. All samples with high genotoxicity assessed by the SOS/umu bioassay possessed significantly high genotoxic effects in the comet assay, and there was a correlation (R2 = 0.736, p < 0.05) between IR and TM in both bioassays. It is concluded that soils in the Tianjin area were seriously contaminated by organic genotoxicants and higher levels of genotoxic effects existed in soils in the urban area of Tianjin as well as in areas near the coastal towns in the northeast part of the city. It can be concluded that a combination of in vivo and in vitro bioassays as a powerful and efficient genotoxicity-assessing tool could facilitate the assessment of genotoxic risk at a regional scale.

Comparison of Reversibility of Rat Forestomach Lesions Induced by Genotoxic and Non‐genotoxic Carcinogens

PubMed Central

Kagawa, Masataka; Hakoi, Kazuo; Yamamoto, Atsushi; Futakuchi, Mitsuru

1993-01-01

Reversibility of forestomach lesions induced by genotoxic and non‐genotoxic carcinogens was compared histopathologically. Groups of 30 to 33 male F344 rats were given dietary 0.1% 8‐nitroquinoline, dietary 0.4–0.2% 2‐(2‐furyl)‐3‐(5‐nitro‐2‐furyl)acrylamide, an intragastric dose of 20 mg/kg body weight N‐methyl‐N′‐nitro‐N‐nitrosoguanidine once a week, or 20 ppm N‐methylnitrosourethane in the drinking water as a genotoxic carcinogen, or 2% butylated hydroxyanisole, 2% caffeic acid, 2% sesamol or 2% 4‐methoxyphenol in the diet as a non‐genotoxic carcinogen for 24 weeks. Ten or 11 rats in each group were killed at week 24. Half of the remainder were maintained on basal diet alone for an additional 24 weeks and the other half were given the same chemical for 48 weeks, and then killed. Forestomach lesions induced by genotoxic carcinogens did not regress after removal of carcinogens. In contrast, simple or papillary hyperplasia (SPH), but not basal cell hyperplasia (BCH), induced by non‐genotoxic carcinogens clearly regressed after cessation of insult. SFH labeling indices in the non‐genotoxic carcinogen‐treated cases decreased after removal of the carcinogenic stimulus whereas BCH values were low irrespective of treatment. Atypical hyperplasia (AH), observed at high incidences in rats treated with genotoxic carcinogens, was also evident in animals receiving non‐genotoxic agents, even after their withdrawal, albeit at low incidences. AH labeling indices remained high even without continued insult. These results indicate that even with non‐genotoxic carcinogens, heritable alterations at the DNA level could occur during strong cell proliferation and result in AH development. This putative preneoplastic lesion might then progress to produce carcinomas. PMID:8276717

Genotoxicity of 1,3-dichloro-2-propanol in the SOS chromotest and in the Ames test. Elucidation of the genotoxic mechanism.

PubMed

Hahn, H; Eder, E; Deininger, C

1991-01-01

1,3-Dichloro-2-propanol (1,3-DCP-OH, glycerol dichlorohydrin) is of great importance in many industrial processes and has been detected in foodstuffs, in particular in soup spices and instant soups. It has been shown to be carcinogenic, genotoxic and mutagenic. Its genotoxic mechanisms are, however, not yet entirely understood. We have investigated whether alcohol dehydrogenase (ADH) catalysed activation to the highly mutagenic and carcinogenic 1,3-dichloroacetone or formation of epichlorohydrin or other genotoxic compounds play a role for mutagenicity and genotoxicity. In our studies, no indications of ADH catalysed formation of 1,3-dichloropropane could be found, although we could demonstrate a clear activation by ADH in the case of 2-chloropropenol. Formation of allyl chloride could also be excluded. We found, however, clear evidence that epichlorohydrin formed chemically in the buffer and medium used in the test is responsible for genotoxicity. No indication was found that enzymatic formation of epichlorohydrin plays a role. Additional mutagenicity and genotoxicity studies with epichlorohydrin also confirmed the hypothesis that genotoxic effects of 1,3-DCP-OH depend on the chemical formation of epichlorohydrin.

GENOTOXICITY OF TOBACCO SMOKE AND TOBACCO SMOKE CONDENSATE: A REVIEW

EPA Science Inventory

Genotoxicity of Tobacco Smoke and Tobacco Smoke Condensate: A Review
Abstract
This report reviews the literature on the genotoxicity of main-stream tobacco smoke and cigarette smoke condensate (CSC) published since 1985. CSC is genotoxic in nearly all systems in which it h...

Genotoxicity risk assessment of diversely substituted quinolines using the SOS chromotest.

PubMed

Duran, Leidy Tatiana Díaz; Rincón, Nathalia Olivar; Galvis, Carlos Eduardo Puerto; Kouznetsov, Vladimir V; Lorenzo, Jorge Luis Fuentes

2015-03-01

Quinolines are aromatic nitrogen compounds with wide therapeutic potential to treat parasitic and microbial diseases. In this study, the genotoxicity of quinoline, 4-methylquinoline, 4-nitroquinoline-1-oxide (4-NQO), and diversely functionalized quinoline derivatives and the influence of the substituents (functional groups and/or atoms) on their genotoxicity were tested using the SOS chromotest. Quinoline derivatives that induce genotoxicity by the formation of an enamine epoxide structure did not induce the SOS response in Escherichia coli PQ37 cells, with the exception of 4-methylquinoline that was weakly genotoxic. The chemical nature of the substitution (C-5 to C-8: hydroxyl, nitro, methyl, isopropyl, chlorine, fluorine, and iodine atoms; C-2: phenyl and 3,4-methylenedioxyphenyl rings) of quinoline skeleton did not significantly modify compound genotoxicities; however, C-2 substitution with α-, β-, or γ-pyridinyl groups removed 4-methylquinoline genotoxicity. On the other hand, 4-NQO derivatives whose genotoxic mechanism involves reduction of the C-4 nitro group were strong inducers of the SOS response. Methyl and nitrophenyl substituents at C-2 of 4-NQO core affected the genotoxic potency of this molecule. The relevance of these results is discussed in relation to the potential use of the substituted quinolines. The work showed the sensitivity of SOS chromotest for studying structure-genotoxicity relationships and bioassay-guided quinoline synthesis. © 2013 Wiley Periodicals, Inc.

Mediator links transcription and DNA repair by facilitating Rad2/XPG recruitment.

PubMed

Eyboulet, Fanny; Cibot, Camille; Eychenne, Thomas; Neil, Helen; Alibert, Olivier; Werner, Michel; Soutourina, Julie

2013-12-01

Mediator is a large multiprotein complex conserved in all eukaryotes. The crucial function of Mediator in transcription is now largely established. However, we found that this complex also plays an important role by connecting transcription with DNA repair. We identified a functional contact between the Med17 Mediator subunit and Rad2/XPG, the 3' endonuclease involved in nucleotide excision DNA repair. Genome-wide location analyses revealed that Rad2 is associated with RNA polymerase II (Pol II)- and Pol III-transcribed genes and telomeric regions in the absence of exogenous genotoxic stress. Rad2 occupancy of Pol II-transcribed genes is transcription-dependent. Genome-wide Rad2 occupancy of class II gene promoters is well correlated with that of Mediator. Furthermore, UV sensitivity of med17 mutants is correlated with reduced Rad2 occupancy of class II genes and concomitant decrease of Mediator interaction with Rad2 protein. Our results suggest that Mediator is involved in DNA repair by facilitating Rad2 recruitment to transcribed genes.

Mediator links transcription and DNA repair by facilitating Rad2/XPG recruitment

PubMed Central

Eyboulet, Fanny; Cibot, Camille; Eychenne, Thomas; Neil, Helen; Alibert, Olivier; Werner, Michel; Soutourina, Julie

2013-01-01

Mediator is a large multiprotein complex conserved in all eukaryotes. The crucial function of Mediator in transcription is now largely established. However, we found that this complex also plays an important role by connecting transcription with DNA repair. We identified a functional contact between the Med17 Mediator subunit and Rad2/XPG, the 3′ endonuclease involved in nucleotide excision DNA repair. Genome-wide location analyses revealed that Rad2 is associated with RNA polymerase II (Pol II)- and Pol III-transcribed genes and telomeric regions in the absence of exogenous genotoxic stress. Rad2 occupancy of Pol II-transcribed genes is transcription-dependent. Genome-wide Rad2 occupancy of class II gene promoters is well correlated with that of Mediator. Furthermore, UV sensitivity of med17 mutants is correlated with reduced Rad2 occupancy of class II genes and concomitant decrease of Mediator interaction with Rad2 protein. Our results suggest that Mediator is involved in DNA repair by facilitating Rad2 recruitment to transcribed genes. PMID:24298055

Leydig cell aging and hypogonadism.

PubMed

Beattie, M C; Adekola, L; Papadopoulos, V; Chen, H; Zirkin, B R

2015-08-01

Leydig cell testosterone (T) production is reduced with age, resulting in reduced serum T levels (hypogonadism). A number of cellular changes have been identified in the steroidogenic pathway of aged Leydig cells that are associated with reduced T formation, including reductions in luteinizing hormone (LH)-stimulated cAMP production, the cholesterol transport proteins steroidogenic acute regulatory (STAR) protein and translocator protein (TSPO), and downstream steroidogenic enzymes of the mitochondria and smooth endoplasmic reticulum. Many of the changes in steroid formation that characterize aged Leydig cells can be elicited by the experimental alteration of the redox environment of young cells, suggesting that changes in the intracellular redox balance may cause reduced T production. Hypogonadism is estimated to affect about 5 million American men, including both aged and young. This condition has been linked to mood changes, worsening cognition, fatigue, depression, decreased lean body mass, reduced bone mineral density, increased visceral fat, metabolic syndrome, decreased libido, and sexual dysfunction. Exogenous T administration is now used widely to elevate serum T levels in hypogonadal men and thus to treat symptoms of hypogonadism. However, recent evidence suggests that men who take exogenous T may face increased risk of stroke, heart attack, and prostate tumorigenesis. Moreover, it is well established that administered T can have suppressive effects on LH, resulting in lower Leydig cell T production, reduced intratesticular T concentration, and reduced spermatogenesis. This makes exogenous T administration inappropriate for men who wish to father children. There are promising new approaches to increase serum T by directly stimulating Leydig cell T production rather than by exogenous T therapy, thus potentially avoiding some of its negative consequences. Copyright © 2015 Elsevier Inc. All rights reserved.

Stress and aversive learning in a wild vertebrate: the role of corticosterone in mediating escape from a novel stressor.

PubMed

Thaker, Maria; Vanak, Abi T; Lima, Steven L; Hews, Diana K

2010-01-01

Elevated plasma corticosterone during stressful events is linked to rapid changes in behavior in vertebrates and can mediate learning and memory consolidation. We tested the importance of acute corticosterone elevation in aversive learning of a novel stressor by wild male eastern fence lizards (Sceloporus undulatus). We found that inhibiting corticosterone elevation (using metyrapone, a corticosterone synthesis blocker) during an encounter with a novel attacker impaired immediate escape responses and limited learning and recall during future encounters. In the wild and in outdoor enclosures, lizards whose acute corticosterone response was blocked by an earlier metyrapone injection did not alter their escape behavior during repeated encounters with the attacker. Control-injected (unblocked) lizards, however, progressively increased flight initiation distance and decreased hiding duration during subsequent encounters. Aversive responses were also initially higher for control lizards exposed to a higher intensity first attack. Further, we demonstrate a role of corticosterone elevation in recollection, since unblocked lizards had heightened antipredator responses 24-28 h later. Exogenously restoring corticosterone levels in metyrapone-injected lizards maintained aversive behaviors and learning at control (unblocked) levels. We suggest that the corticosterone mediation of antipredator behaviors and aversive learning is a critical and general mechanism for the behavioral flexibility of vertebrate prey.

Rapid Mobilization of Membrane Lipids in Wheat Leaf-Sheaths during Incompatible Interactions with Hessian Fly*

PubMed Central

Zhu, Lieceng; Liu, Xuming; Wang, Haiyan; Khajuria, Chitvan; Reese, John C.; Whitworth, R. Jeff; Welti, Ruth; Chen, Ming-Shun

2013-01-01

Hessian fly (HF) is a biotrophic insect that interacts with wheat on a gene-for-gene basis. We profiled changes in membrane lipids in two isogenic wheat lines: a susceptible line and its backcrossed offspring containing the resistance gene H13. Our results revealed a 32 to 45% reduction in total concentrations of 129 lipid species in resistant plants during incompatible interactions within 24 h after HF attack. A smaller and delayed response was observed in susceptible plants during compatible interactions. Microarray and real-time PCR analyses of 168 lipid-metabolism related transcripts revealed that the abundance of many of these transcripts increased rapidly in resistant plants after HF attack, but did not change in susceptible plants. In association with the rapid mobilization of membrane lipids, the concentrations of some fatty acids and 12-oxo-phytodienoic acid (OPDA) increased specifically in resistant plants. Exogenous application of OPDA increased mortality of HF larvae significantly. Collectively, our data, along with previously published results, indicate that the lipids were mobilized through lipolysis, producing free fatty acids, which were likely further converted into oxylipins and other defense molecules. Our results suggest that rapid mobilization of membrane lipids constitutes an important step for wheat to defend against HF attack. PMID:22668001

Genotoxicity of municipal landfill leachate on root tips of Vicia faba.

PubMed

Sang, Nan; Li, Guangke

2004-06-13

The genotoxicity of municipal landfill leachate was studied using the Vicia faba root-tip cytogenetic bioassay. Results show that landfill leachates collected in different seasons decreased the mitotic index (MI) and caused significant increases of micronucleus (MN) frequencies and anaphase aberration (AA) frequencies in a concentration-dependent manner (concentration expressed as 'chemical oxygen demand' measured by the method of potassium dichromate oxidation (COD(Cr))). In addition, a seasonal difference in genotoxicity induced by leachate was observed. The results confirm that leachate is a genotoxic agent in plant cells and imply that exposure to leachate in the aquatic environment may pose a potential genotoxic risk to organisms. The results also show that the V. faba cytogenetic bioassay is efficient, simple and reproducible in genotoxicity studies of leachate, and that there is a correlation between the genotoxicity and the chemical measurement (COD(Cr)) of leachate.

Current investigations into the genotoxicity of zinc oxide and silica nanoparticles in mammalian models in vitro and in vivo: carcinogenic/genotoxic potential, relevant mechanisms and biomarkers, artifacts, and limitations

PubMed Central

Kwon, Jee Young; Koedrith, Preeyaporn; Seo, Young Rok

2014-01-01

Engineered nanoparticles (NPs) are widely used in many sectors, such as food, medicine, military, and sport, but their unique characteristics may cause deleterious health effects. Close attention is being paid to metal NP genotoxicity; however, NP genotoxic/carcinogenic effects and the underlying mechanisms remain to be elucidated. In this review, we address some metal and metal oxide NPs of interest and current genotoxicity tests in vitro and in vivo. Metal NPs can cause DNA damage such as chromosomal aberrations, DNA strand breaks, oxidative DNA damage, and mutations. We also discuss several parameters that may affect genotoxic response, including physicochemical properties, widely used assays/end point tests, and experimental conditions. Although potential biomarkers of nanogenotoxicity or carcinogenicity are suggested, inconsistent findings in the literature render results inconclusive due to a variety of factors. Advantages and limitations related to different methods for investigating genotoxicity are described, and future directions and recommendations for better understanding genotoxic potential are addressed. PMID:25565845

Lack of genotoxicity in vivo for food color additive Allura Red AC.

PubMed

Bastaki, Maria; Farrell, Thomas; Bhusari, Sachin; Pant, Kamala; Kulkarni, Rohan

2017-07-01

Allura Red AC is an approved food color additive internationally with INS number 129, in the United States as food color subject to batch certification "Food, Drug, and Cosmetic" (FD&C) Red No. 40, and in Europe as food color additive with E number 129. In their evaluation of the color (2013), the European Food Safety Authority (EFSA) expressed concerns of potential genotoxicity, based primarily on one genotoxicity study that was not conducted according to Guidelines. The present in vivo genotoxicity study was conducted according to OECD Guidelines in response to EFSA's request for additional data. The animal species and strain, and the tissues examined were selected specifically to address the previously reported findings. The results show clear absence of genotoxic activity for Allura Red AC, in the bone marrow micronucleus assay and the Comet assay in the liver, stomach, and colon. These data addressed EFSA's concerns for genotoxicity. The Joint WHO/FAO Committee on Food Additives (JECFA) (2016) also reviewed the study and concluded that there is no genotoxicity concern for Allura Red AC. Negative findings in parallel genotoxicity studies on Tartrazine and Ponceau 4R (published separately) are consistent with lack of genotoxicity for azo dyes used as food colors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lack of genotoxicity in vivo for food color additive Tartrazine.

PubMed

Bastaki, Maria; Farrell, Thomas; Bhusari, Sachin; Pant, Kamala; Kulkarni, Rohan

2017-07-01

Tartrazine is approved as a food color additive internationally with INS number 102, in the United States as food color subject to batch certification "Food, Drug, and Cosmetic" (FD&C) Yellow No. 5, and in Europe as food color additive with E number 102. In their evaluation of the color (2013), the European Food Safety Authority (EFSA) expressed concerns of potential genotoxicity, based primarily on one genotoxicity study that was not conducted according to Guidelines. The present in vivo genotoxicity study was conducted according to OECD Guidelines in response to EFSA's request for additional data. The animal species and strain, and the tissues examined were selected specifically to address the previously reported findings. The results of this study show clear absence of genotoxic activity for Tartrazine, in the bone marrow micronucleus assay and the Comet assay in the liver, stomach, and colon. These data addressed EFSA's concerns for genotoxicity. The Joint WHO/FAO Committee on Food Additives (JECFA) (2016) also reviewed these data and concluded that there is no genotoxicity concern for Tartrazine. Negative findings in parallel genotoxicity studies on Allura Red AC and Ponceau 4R (published separately) are consistent with lack of genotoxicity for azo dyes used as food colors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of the in vitro and in vivo genotoxicity of extracts and indole monoterpene alkaloid from the roots of Galianthe thalictroides (Rubiaceae).

PubMed

Fernandes, L M; Garcez, W S; Mantovani, M S; Figueiredo, P O; Fernandes, C A; Garcez, F R; Guterres, Z R

2013-09-01

Roots of Galianthe thalictroides K. Schum. (Rubiaceae) are used in folk medicine in the State of Mato Grosso do Sul, Brazil, for treating and preventing cancer. To gain information about the genotoxicity of extracts (aqueous and EtOH), the CHCl₃ phase resulting from partition of the EtOH extract and the indole monoterpene alkaloid 1 obtained from this plant. The genotoxicity of 1 and extracts was evaluated in vivo through the Drosophila melanogaster wing Somatic Mutation and Recombination Test - SMART, while in vitro cytotoxic (MTT) and Comet assays were performed only with alkaloid 1. The results obtained with the SMART test indicated that the aqueous extract had no genotoxic activity. The EtOH extract was not genotoxic to ST descendants but genotoxic to HB ones. The CHCl₃ phase was genotoxic and cytotoxic. Alkaloid 1 showed significant mutational events with SMART, in the cytotoxicity assay (MTT), it showed a high cytotoxicity for human hepatoma cells (HepG2), whereas for the Comet assay, not showing genotoxic activity. The ethanol extract was shown to be genotoxic to HB descendants in the SMART assay, while the results obtained in this test for the monoterpene indole alkaloid 1 isolated from this extract. Copyright © 2013 Elsevier Ltd. All rights reserved.

Fecal water genotoxicity in healthy free-living young Italian people.

PubMed

Daniela, Erba; Sara, Soldi; Marcella, Malavolti; Giovanni, Aragone; Meynier, Alexandra; Sophie, Vinoy; Cristina, Casiraghi M

2014-02-01

Dietary habit affects the composition of human feces thus determining intestinal environment and exposure of colon mucosa to risk factors. Fecal water (FW) citotoxicity and genotoxicity were investigated in 33 healthy young Italian people, as well as the relationship between genotoxicity and nutrient intake or microflora composition. Two fecal samples were collected at 2 weeks apart and 3-d dietary diary was recorded for each volunteer. Cytotoxicity was measured using the Trypan Blue Dye Exclusion assay and genotoxicity using the Comet Assay (alkaline single-cell electrophoresis). Fecal bifidobacteria, total microbial count and nutrient intakes were also assessed. High intra- and inter-variability in genotoxicity data and in bacteria counts were found. None of the FW samples were citotoxic, but 90% of FW samples were genotoxic. Seventy five percent indicated intermediate and 15% were highly genotoxic. There was a different sex-related distribution. Genotoxicity was positively correlated to the total lipid intake in females and to the bifidobacteria/total bacteria count ratio in male volunteers. These results demonstrate that the majority of FW samples isolated from free-living Italian people show intermediate level of genotoxicity and sustain a relation between this possible non-invasive marker of colorectal cancer risk with both dietary habits and colonic ecosystem. Copyright © 2013 Elsevier Ltd. All rights reserved.

The RNA surveillance protein SMG1 activates p53 in response to DNA double-strand breaks but not exogenously oxidized mRNA

PubMed Central

Gewandter, Jennifer S; Bambara, Robert A

2011-01-01

DNA damage, stalled replication forks, errors in mRNA splicing and availability of nutrients activate specific phosphatidylinositiol-3-kinase-like kinases (PIKKs) that in turn phosphorylate downstream targets such as p53 on serine 15. While the PIKK proteins ATM and ATR respond to specific DNA lesions, SMG1 responds to errors in mRNA splicing and when cells are exposed to genotoxic stress. Yet, whether genotoxic stress activates SMG1 through specific types of DNA lesions or RNA damage remains poorly understood. Here, we demonstrate that siRNA oligonucleotides targeting the mRNA surveillance proteins SMG1, Upf1, Upf2 or the PIKK protein ATM attenuated p53 (ser15) phosphorylation in cells damaged by high oxygen (hyperoxia), a model of persistent oxidative stress that damages nucleotides. In contrast, loss of SMG1 or ATM, but not Upf1 or Upf2 reduced p53 (ser15) phosphorylation in response to DNA double strand breaks produced by expression of the endonuclease I-PpoI. To determine whether SMG1-dependent activation of p53 was in response to oxidative mRNA damage, mRNA encoding green fluorescence protein (GFP) transcribed in vitro was oxidized by Fenton chemistry and transfected into cells. Although oxidation of GFP mRNA resulted in dose-dependent fragmentation of the mRNA and reduced expression of GFP, it did not stimulate p53 or the p53-target gene p21. These findings establish SMG1 activates p53 in response to DNA double strand breaks independent of the RNA surveillance proteins Upf1 or Upf2; however, these proteins can stimulate p53 in response to oxidative stress but not necessarily oxidized RNA. PMID:21701263

Herbivore-induced blueberry volatiles and intra-plant signaling.

PubMed

Rodriguez-Saona, Cesar R

2011-12-18

Herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack. These HIPVs are mainly regulated by the defensive plant hormone jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA). Over the past 3 decades researchers have documented that HIPVs can repel or attract herbivores, attract the natural enemies of herbivores, and in some cases they can induce or prime plant defenses prior to herbivore attack. In a recent paper, I reported that feeding by gypsy moth caterpillars, exogenous MeJA application, and mechanical damage induce the emissions of volatiles from blueberry plants, albeit differently. In addition, blueberry branches respond to HIPVs emitted from neighboring branches of the same plant by increasing the levels of JA and resistance to herbivores (i.e., direct plant defenses), and by priming volatile emissions (i.e., indirect plant defenses). Similar findings have been reported recently for sagebrush, poplar, and lima beans. Here, I describe a push-pull method for collecting blueberry volatiles induced by herbivore (gypsy moth) feeding, exogenous MeJA application, and mechanical damage. The volatile collection unit consists of a 4 L volatile collection chamber, a 2-piece guillotine, an air delivery system that purifies incoming air, and a vacuum system connected to a trap filled with Super-Q adsorbent to collect volatiles. Volatiles collected in Super-Q traps are eluted with dichloromethane and then separated and quantified using Gas Chromatography (GC). This volatile collection method was used in my study to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants. These methods are described here. Briefly, undamaged blueberry branches are exposed to HIPVs from neighboring branches within the same plant. Using the same techniques described above, volatiles emitted from branches after exposure to HIPVs are collected and analyzed.

Genotoxicity Expert Panel review: weight of evidence evaluation of the genotoxicity of glyphosate, glyphosate-based formulations, and aminomethylphosphonic acid.

PubMed

Brusick, David; Aardema, Marilyn; Kier, Larry; Kirkland, David; Williams, Gary

2016-09-01

In 2015, the International Agency for Research on Cancer (IARC) published a monograph concluding there was strong evidence for genotoxicity of glyphosate and glyphosate formulations and moderate evidence for genotoxicity of the metabolite aminomethylphosphonic acid (AMPA). These conclusions contradicted earlier extensive reviews supporting the lack of genotoxicity of glyphosate and glyphosate formulations. The IARC Monograph concluded there was strong evidence of induction of oxidative stress by glyphosate, glyphosate formulations, and AMPA. The Expert Panel reviewed the genotoxicity and oxidative stress data considered in the IARC Monograph, together with other available data not considered by IARC. The Expert Panel defined and used a weight of evidence (WoE) approach that included ranking of studies and endpoints by the strength of their linkage to events associated with carcinogenic mechanisms. Importantly, the Expert Panel concluded that there was sufficient information available from a very large number of regulatory genotoxicity studies that should have been considered by IARC. The WoE approach, the inclusion of all relevant regulatory studies, and some differences in interpretation of individual studies led to significantly different conclusions by the Expert Panel compared with the IARC Monograph. The Expert Panel concluded that glyphosate, glyphosate formulations, and AMPA do not pose a genotoxic hazard and the data do not support the IARC Monograph genotoxicity evaluation. With respect to carcinogenicity classification and mechanism, the Expert Panel concluded that evidence relating to an oxidative stress mechanism of carcinogenicity was largely unconvincing and that the data profiles were not consistent with the characteristics of genotoxic carcinogens.

A novel toxicogenomics-based approach to categorize (non-)genotoxic carcinogens.

PubMed

Schaap, Mirjam M; Wackers, Paul F K; Zwart, Edwin P; Huijskens, Ilse; Jonker, Martijs J; Hendriks, Giel; Breit, Timo M; van Steeg, Harry; van de Water, Bob; Luijten, Mirjam

2015-12-01

Alternative methods to detect non-genotoxic carcinogens are urgently needed, as this class of carcinogens goes undetected in the current testing strategy for carcinogenicity under REACH. A complicating factor is that non-genotoxic carcinogens act through several distinctive modes of action, which makes prediction of their carcinogenic property difficult. We have recently demonstrated that gene expression profiling in primary mouse hepatocytes is a useful approach to categorize non-genotoxic carcinogens according to their modes of action. In the current study, we improved the methods used for analysis and added mouse embryonic stem cells as a second in vitro test system, because of their features complementary to hepatocytes. Our approach involved an unsupervised analysis based on the 30 most significantly up- and down-regulated genes per chemical. Mouse embryonic stem cells and primary mouse hepatocytes were exposed to a selected set of chemicals and subsequently subjected to gene expression profiling. We focused on non-genotoxic carcinogens, but also included genotoxic carcinogens and non-carcinogens to test the robustness of this approach. Application of the optimized comparison approach resulted in improved categorization of non-genotoxic carcinogens. Mouse embryonic stem cells were a useful addition, especially for genotoxic substances, but also for detection of non-genotoxic carcinogens that went undetected by primary hepatocytes. The approach presented here is an important step forward to categorize chemicals, especially those that are carcinogenic.

Dissecting modes of action of non-genotoxic carcinogens in primary mouse hepatocytes.

PubMed

Schaap, Mirjam M; Zwart, Edwin P; Wackers, Paul F K; Huijskens, Ilse; van de Water, Bob; Breit, Timo M; van Steeg, Harry; Jonker, Martijs J; Luijten, Mirjam

2012-11-01

Under REACH, the European Community Regulation on chemicals, the testing strategy for carcinogenicity is based on in vitro and in vivo genotoxicity assays. Given that non-genotoxic carcinogens are negative for genotoxicity and chronic bioassays are no longer regularly performed, this class of carcinogens will go undetected. Therefore, test systems detecting non-genotoxic carcinogens, or even better their modes of action, are required. Here, we investigated whether gene expression profiling in primary hepatocytes can be used to distinguish different modes of action of non-genotoxic carcinogens. For this, primary mouse hepatocytes were exposed to 16 non-genotoxic carcinogens with diverse modes of action. Upon profiling, pathway analysis was performed to obtain insight into the biological relevance of the observed changes in gene expression. Subsequently, both a supervised and an unsupervised comparison approach were applied to recognize the modes of action at the transcriptomic level. These analyses resulted in the detection of three of eight compound classes, that is, peroxisome proliferators, metalloids and skin tumor promotors. In conclusion, gene expression profiles in primary hepatocytes, at least in rodent hepatocytes, appear to be useful to detect some, certainly not all, modes of action of non-genotoxic carcinogens.

A comparison of genotoxicity change in reclaimed wastewater from different disinfection processes.

PubMed

Chai, Qiwan; Hu, Allen; Qian, Yukun; Ao, Xiuwei; Liu, Wenjun; Yang, Hongwei; Xie, Yuefeng F

2018-01-01

Effluents before disinfection from four wastewater reclamation plants were treated with chlorine (Cl 2 ), ozone (O 3 ), chlorine dioxide (ClO 2 ), medium-pressure ultraviolet (MPUV) and four different combinations of the above, to evaluate the effect of disinfection processes on the genotoxicity removal by the SOS/umu test. Results showed that the genotoxicity increased after MPUV irradiation (10-100 mJ/cm 2 ), but declined when adopting other disinfection processes. The effectiveness of genotoxicity reduction by five chemical disinfectants was identified as: O 3  > pre-ozonation with Cl 2  ≈ ClO 2  > combination of ClO 2 and Cl 2  > Cl 2 . The sequential combination of MPUV, Cl 2 and O 3 reduced the genotoxicity to a level similar to the source water. The influence of differential disinfection process varied on iodinated wastewater, which is closely related to the competitive reactions between disinfectants, iodine and dissolved organic matters. The removal of genotoxic pollutants and the formation of genotoxic disinfection by-products are the two major factors that lead to the change in genotoxicity during disinfection. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Theoretical Study of 8-Chloro-9-Hydroxy-Aflatoxin B₁, the Conversion Product of Aflatoxin B₁ by Neutral Electrolyzed Water.

PubMed

Escobedo-González, René; Méndez-Albores, Abraham; Villarreal-Barajas, Tania; Aceves-Hernández, Juan Manuel; Miranda-Ruvalcaba, René; Nicolás-Vázquez, Inés

2016-07-21

Theoretical studies of 8-chloro-9-hydroxy-aflatoxin B₁ (2) were carried out by Density Functional Theory (DFT). This molecule is the reaction product of the treatment of aflatoxin B₁ (1) with hypochlorous acid, from neutral electrolyzed water. Determination of the structural, electronic and spectroscopic properties of the reaction product allowed its theoretical characterization. In order to elucidate the formation process of 2, two reaction pathways were evaluated-the first one considering only ionic species (Cl⁺ and OH(-)) and the second one taking into account the entire hypochlorous acid molecule (HOCl). Both pathways were studied theoretically in gas and solution phases. In the first suggested pathway, the reaction involves the addition of chlorenium ion to 1 forming a non-classic carbocation assisted by anchimeric effect of the nearest aromatic system, and then a nucleophilic attack to the intermediate by the hydroxide ion. In the second studied pathway, as a first step, the attack of the double bond from the furanic moiety of 1 to the hypochlorous acid is considered, accomplishing the same non-classical carbocation, and again in the second step, a nucleophilic attack by the hydroxide ion. In order to validate both reaction pathways, the atomic charges, the highest occupied molecular orbital and the lowest unoccupied molecular orbital were obtained for both substrate and product. The corresponding data imply that the C₉ atom is the more suitable site of the substrate to interact with the hydroxide ion. It was demonstrated by theoretical calculations that a vicinal and anti chlorohydrin is produced in the terminal furan ring. Data of the studied compound indicate an important reduction in the cytotoxic and genotoxic potential of the target molecule, as demonstrated previously by our research group using different in vitro assays.

[Genotoxicity of drinking water during chlorine and chloramine disinfection and the influence of disinfection conditions using the umu-test].

PubMed

Liu, Qing; Zhang, Li-Ping; Liu, Wen-Jun; Nie, Xue-Biao; Zhang, Su-Xia; Zhang, Shun

2010-01-01

In this study, the effects of disinfectant dosage, reaction time and the ratio of Cl2 to N of disinfectant on genotoxicity of effluent of ozone-biological activated carbon (O3-BAC) during chlorine or chloramine disinfection were investigated using umu-test. It was found that, the genotoxicity of effluent of O3-BAC before disinfection ranged from 20-70 ng/L, and it increased after disinfection by chlorine or chloramines. With the same reaction time(24 h), genotoxicity after chlorination (40-95 ng/L) was higher than that after chloramination (20-40 ng/L) under same initial dosage. For chlorination, with initial dosage increasing from 0 mg/L to 10 mg/L, genotoxicity increased firstly, and got the maximum value at about 0.5-1 mg/L dosage, then decreased and got the minimum value at about 3-5 mg/L dosage, and finally increased again. For chloramination, genotoxicity didn't change that much. With the dosage of 3 mg/L and reaction time increasing from 0 h to 72 h, no matter for chlorine or chloramines disinfection, genotoxicity of effluent of O3-BAC both increased firstly, and got the maximum value at about 2 h, then decreased and got the minimum value at about 18 h, and finally increased again, and genotoxicity after chlorine disinfection (83-120 ng/L) was higher than that after chloramines disinfection (20-62 ng/L) under same reaction time. Further more, effects of the different ratios of Cl2 to N of disinfectant on genotoxicity of effluent of O3-BAC were also studied. Results of this study demonstrate that under test conditions, chloramine disinfection is safer than chlorine disinfection in the aspect of genotoxicity for drinking water, and the changes of genotoxicity are different from those of total HAAs.

Recent Advances in In Vivo Genotoxicity Testing: Prediction of Carcinogenic Potential Using Comet and Micronucleus Assay in Animal Models

PubMed Central

Kang, Seung Hun; Kwon, Jee Young; Lee, Jong Kwon; Seo, Young Rok

2013-01-01

Genotoxic events have been known as crucial step in the initiation of cancer. To assess the risk of cancer, genotoxicity assays, including comet, micronucleus (MN), chromosomal aberration, bacterial reverse, and sister chromatid exchange assay, can be performed. Compared with in vitro genotoxicity assay, in vivo genotoxicity assay has been used to verify in vitro assay result and definitely provide biological significance for certain organs or cell types. The comet assay can detect DNA strand breaks as markers of genotoxicity. Methods of the in vivo comet assay have been established by Japanese Center for the Validation of Alternative Methods (JaCVAM) validation studies depending on tissue and sample types. The MN can be initiated by segregation error and lagging acentric chromosome fragment. Methods of the in vivo MN assay have been established by Organization for Economic Co-operation and Development (OECD) test guidelines and many studies. Combining the in vivo comet and MN assay has been regarded as useful methodology for evaluating genetic damage, and it has been used in the assessment of potential carcinogenicity by complementarily presenting two distinct endpoints of the in vivo genotoxicity individual test. Few studies have investigated the quantitative relation between in vivo genotoxicity results and carcinogenicity. Extensive studies emphasizes that positive correlation is detectable. This review summarizes the results of the in vivo comet and MN assays that have investigated the genotoxicity of carcinogens as classified by the International Agency for Research on Cancer (IARC) carcinogenicity database. As a result, these genotoxicity data may provide meaningful information for the assessment of potential carcinogenicity and for implementation in the prevention of cancer. PMID:25337557

Fluorescence-based recombination assay for sensitive and specific detection of genotoxic carcinogens in human cells.

PubMed

Ireno, Ivanildce C; Baumann, Cindy; Stöber, Regina; Hengstler, Jan G; Wiesmüller, Lisa

2014-05-01

In vitro genotoxicity tests are known to suffer from several shortcomings, mammalian cell-based assays, in particular, from low specificities. Following a novel concept of genotoxicity detection, we developed a fluorescence-based method in living human cells. The assay quantifies DNA recombination events triggered by DNA double-strand breaks and damage-induced replication fork stalling predicted to detect a broad spectrum of genotoxic modes of action. To maximize sensitivities, we engineered a DNA substrate encompassing a chemoresponsive element from the human genome. Using this substrate, we screened various human tumor and non-transformed cell types differing in the DNA damage response, which revealed that detection of genotoxic carcinogens was independent of the p53 status but abrogated by apoptosis. Cell types enabling robust and sensitive genotoxicity detection were selected for the generation of reporter clones with chromosomally integrated DNA recombination substrate. Reporter cell lines were scrutinized with 21 compounds, stratified into five sets according to the established categories for identification of carcinogenic compounds: genotoxic carcinogens ("true positives"), non-genotoxic carcinogens, compounds without genotoxic or carcinogenic effect ("true negatives") and non-carcinogenic compounds, which have been reported to induce chromosomal aberrations or mutations in mammalian cell-based assays ("false positives"). Our results document detection of genotoxic carcinogens in independent cell clones and at levels of cellular toxicities <60 % with a sensitivity of >85 %, specificity of ≥90 % and detection of false-positive compounds <17 %. Importantly, through testing cyclophosphamide in combination with primary hepatocyte cultures, we additionally provide proof-of-concept for the identification of carcinogens requiring metabolic activation using this novel assay system.

A Novel Strategy to Predict Carcinogenicity of Antiparasitics Based on a Combination of DNA Lesions and Bacterial Mutagenicity Tests

PubMed Central

Liu, Qianying; Lei, Zhixin; Zhu, Feng; Ihsan, Awais; Wang, Xu; Yuan, Zonghui

2017-01-01

Genotoxicity and carcinogenicity testing of pharmaceuticals prior to commercialization is requested by regulatory agencies. The bacterial mutagenicity test was considered having the highest accuracy of carcinogenic prediction. However, some evidences suggest that it always results in false-positive responses when the bacterial mutagenicity test is used to predict carcinogenicity. Along with major changes made to the International Committee on Harmonization guidance on genotoxicity testing [S2 (R1)], the old data (especially the cytotgenetic data) may not meet current guidelines. This review provides a compendium of retrievable results of genotoxicity and animal carcinogenicity of 136 antiparasitics. Neither genotoxicity nor carcinogenicity data is available for 84 (61.8%), while 52 (38.2%) have been evaluated in at least one genotoxicity or carcinogenicity study, and only 20 (14.7%) in both genotoxicity and carcinogenicity studies. Among 33 antiparasitics with at least one old result in in vitro genotoxicity, 15 (45.5%) are in agreement with the current ICH S2 (R1) guidance for data acceptance. Compared with other genotoxicity assays, the DNA lesions can significantly increase the accuracy of prediction of carcinogenicity. Together, a combination of DNA lesion and bacterial tests is a more accurate way to predict carcinogenicity. PMID:29170735

Assessing the genotoxicities of sparteine and compounds isolated from Lupinus mexicanus and L. montanus seeds by using comet assay.

PubMed

Silva, M R; Alvarez, C M; García, P M; Ruiz, M A

2014-12-12

The genus Lupinus is widely distributed. Its seeds are used for animal and human food, and Lupinus possesses pharmacological potential because of its high content of quinolizidine alkaloids and flavonoids; however, there is little available information about its genotoxicity. We used the comet assay and staminal nuclei of Tradescantia (clone 4430) to evaluate the in vitro genotoxicity of 4 concentrations (0.01, 0.1, 0.5, and 1.0 mM) of alkaloid extracts of Lupinus mexicanus and Lupinus montanus, flavonoids of L. mexicanus, and commercial sparteine; nitrosodiethylamine was used as a positive control and untreated nuclei were used as a negative control. All concentrations of L. mexicanus and L. montanus showed significant genotoxic activity (P ≤ 0.05). A similar behavior was observed for flavonoid extracts of L. montanus except the 1.0 mM concentration. Sparteine showed genotoxic activity only at 0.5 mM. The order of genotoxicity of the compounds studied was as follows: L. mexicanus > L. montanus > flavonoids of L. montanus > sparteine. There is evident genotoxic activity in the compounds that were studied, particularly at lower concentrations (0.01 and 0.1 mM). Given the limited information about the genotoxicity of the compounds of L. mexicanus and L. montanus, further studies are necessary.

Soil genotoxicity assessment: a new stategy based on biomolecular tools and plant bioindicators.

PubMed

Citterio, Sandra; Aina, Roberta; Labra, Massimo; Ghiani, Alessandra; Fumagalli, Pietro; Sgorbati, Sergio; Santagostino, Angela

2002-06-15

The setting up of efficient early warning systems is a challenge to research for preventing environmental alteration and human disease. In this paper, we report the development and the field application of a new biomonitoring methodology for assessing soil genotoxicity. In the first part, the use of amplified fragment length polymorphism and flow cytometry techniques to detect DNA damage induced by soils artificially contaminated with heavy metals as potentially genotoxic compounds is explained. Results show that the combination of the two techniques leads to efficient detection of the sublethal genotoxic effect induced in the plant bioindicator by contaminated soil. By contrast, the classic mortality, root, and shoot growth vegetative endpoints prove inappropriate for assessing soil genotoxicity because, although they cause genotoxic damage, some heavy metals do not affect sentinel plant development negatively. The statistical elaboration of the data obtained led to the development of a statistical predictive model which differentiates four different levels of soil genotoxic pollution and can be used everywhere. The second part deals with the application of the biomonitoring protocol in the genotoxic assessment of two areas surrounding a steelworks in northern Italy and the effectiveness of this methodology. In this particular case, in these areas, the predictive model reveals a pollution level strictly correlated to the heavy metal concentrations revealed by traditional chemical analysis.

The influence of organic solvents on estimates of genotoxicity and antigenotoxicity in the SOS chromotest.

PubMed

Quintero, Nathalia; Stashenko, Elena E; Fuentes, Jorge Luis

2012-04-01

In this work, the toxicity and genotoxicity of organic solvents (acetone, carbon tetrachloride, dichloromethane, dimethylsulfoxide, ethanol, ether and methanol) were studied using the SOS chromotest. The influence of these solvents on the direct genotoxicity induced by the mutagens mitomycin C (MMC) and 4-nitroquinoline-1-oxide (4-NQO) were also investigated. None of the solvents were genotoxic in Escherichia coli PQ37. However, based on the inhibition of protein synthesis assessed by constitutive alkaline phosphatase activity, some solvents (carbon tetrachloride, dimethylsulfoxide, ethanol and ether) were toxic and incompatible with the SOS chromotest. Solvents that were neither toxic nor genotoxic to E. coli (acetone, dichloromethane and methanol) significantly reduced the genotoxicity of MMC and 4-NQO. When these solvents were used to dissolve vitamin E they increased the antigenotoxic activity of this compound, possibly through additive or synergistic effects. The relevance of these results is discussed in relation to antigenotoxic studies. These data indicate the need for careful selection of an appropriate diluent for the SOS chromotest since some solvents can modulate genotoxicity and antigenotoxicity.

Testing chemical carcinogenicity by using a transcriptomics HepaRG-based model?

PubMed Central

Doktorova, T. Y.; Yildirimman, Reha; Ceelen, Liesbeth; Vilardell, Mireia; Vanhaecke, Tamara; Vinken, Mathieu; Ates, Gamze; Heymans, Anja; Gmuender, Hans; Bort, Roque; Corvi, Raffaella; Phrakonkham, Pascal; Li, Ruoya; Mouchet, Nicolas; Chesne, Christophe; van Delft, Joost; Kleinjans, Jos; Castell, Jose; Herwig, Ralf; Rogiers, Vera

2014-01-01

The EU FP6 project carcinoGENOMICS explored the combination of toxicogenomics and in vitro cell culture models for identifying organotypical genotoxic- and non-genotoxic carcinogen-specific gene signatures. Here the performance of its gene classifier, derived from exposure of metabolically competent human HepaRG cells to prototypical non-carcinogens (10 compounds) and hepatocarcinogens (20 compounds), is reported. Analysis of the data at the gene and the pathway level by using independent biostatistical approaches showed a distinct separation of genotoxic from non-genotoxic hepatocarcinogens and non-carcinogens (up to 88 % correct prediction). The most characteristic pathway responding to genotoxic exposure was DNA damage. Interlaboratory reproducibility was assessed by blindly testing of three compounds, from the set of 30 compounds, by three independent laboratories. Subsequent classification of these compounds resulted in correct prediction of the genotoxicants. As expected, results on the non-genotoxic carcinogens and the non-carcinogens were less predictive. In conclusion, the combination of transcriptomics with the HepaRG in vitro cell model provides a potential weight of evidence approach for the evaluation of the genotoxic potential of chemical substances. PMID:26417288

Reaction kinetics and transformation of carbadox and structurally related compounds with aqueous chlorine.

PubMed

Shah, Amisha D; Kim, Jae-Hong; Huang, Ching-Hua

2006-12-01

The potential release of carbadox (CDX), a commonly used antibacterial agent in swine husbandry, into water systems is of a concern due to its carcinogenic and genotoxic effects. Until this study, the reactivity of carbadox (possessing quinoxaline N,N'-dioxide and hydrazone moieties) toward aqueous chlorine has yetto be investigated in depth. Chemical reactivity, reaction kinetics, and transformation pathways of carbadox and structurally related compounds with free chlorine under typical water treatment conditions were determined. This study found that only CDX and desoxycarbadox (DCDX), a main metabolite of CDX with no ring N-oxide groups, react rapidly with free chlorine while other structurally related compounds including olaquindox, quindoxin, quinoxaline N-oxide, quinoxaline, and quinoline N-oxide do not. The reaction kinetics of CDX and DCDX with chlorine are highly pH dependent (e.g., the apparent second-order rate constant, kapp, for CDX ranges from 51.8 to 3.15 x 10(4) M(-1)s(-1) at pH 4-11). The high reactivity of CDX and DCDX to chlorine involves deprotonation of their hydrazone N-H moieties where initial chlorine attack results in a reactive intermediate that is further attacked by nucleophiles in the matrix to yield non-chlorinated, hydroxylated, and larger molecular weight byproducts. All of the CDX's byproducts retain their biologically active N-oxide groups, suggesting that they may remain as active antibacterial agents.

Genotoxic and anti-genotoxic effects of esculin and its oligomer fractions against mitomycin C-induced DNA damages in mice.

PubMed

Mokdad Bzeouich, Imen; Mustapha, Nadia; Maatouk, Mouna; Ghedira, Kamel; Ghoul, Mohamed; Chekir-Ghedira, Leila

2016-12-01

Mitomycin C is one of the most effective chemotherapeutic drugs against various solid tumors. However, despite its wide spectrum of clinical benefits, this agent is capable of inducing various types of genotoxicity. In this study, we investigated the effect of esculin and its oligomer fractions (E1, E2 and E3) against mitomycin C induced genotoxicity in liver and kidney cells isolated from Balb/C mice using the comet assay. Esculin and its oligomer fractions were not genotoxic at the tested doses (20 mg/kg and 40 mg/kg b.w). A significant decrease in DNA damages was observed, suggesting a protective role of esculin and its oligomer fractions against the genotoxicity induced by mitomycin C on liver and kidney cells. Moreover, esculin and its oligomer fractions did not induce an increase of malondialdehyde levels. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of the in vivo genotoxicity of Allura Red AC (Food Red No. 40).

PubMed

Honma, Masamitsu

2015-10-01

Allura Red AC (Food Red No. 40) is a red azo dye that is used for food coloring in beverage and confectionary products. However, its genotoxic properties remain controversial. To clarify the in vivo genotoxicity, we treated mice with Allura Red AC and investigated the induction of DNA damage (liver, glandular stomach), clastogenicity/anuegenicity (bone marrow), and mutagenicity (liver, glandular stomach) using Comet assays, micronucleus tests, and transgenic gene mutation assays, respectively. All studies were conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guideline. Although Allura Red AC was administered up to the maximum doses recommended by the OECD guideline, no genotoxic effect was observed in any of the genotoxic endpoints. These data clearly show no evidence of in vivo genotoxic potential of Allura Red AC administered up to the maximum doses in mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

The comet assay for the evaluation of genotoxic potential of landfill leachate.

PubMed

Widziewicz, Kamila; Kalka, Joanna; Skonieczna, Magdalena; Madej, Paweł

2012-01-01

Genotoxic assessment of landfill leachate before and after biological treatment was conducted with two human cell lines (Me45 and NHDF) and Daphnia magna somatic cells. The alkali version of comet assay was used to examine genotoxicity of leachate by DNA strand breaks analysis and its repair dynamics. The leachate samples were collected from Zabrze landfill, situated in the Upper Silesian Industrial District, Poland. Statistically significant differences (Kruskal-Wallice ANOVA rank model) were observed between DNA strand breaks in cells incubated with leachate before and after treatment (P < 0.001). Nonparametric Friedman ANOVA confirmed time-reliable and concentration-reliable cells response to leachate concentration. Examinations of chemical properties showed a marked decrease in leachate parameters after treatment which correlate to reduced genotoxicity towards tested cells. Obtained results demonstrate that biological cotreatment of leachate together with municipal wastewater is an efficient method for its genotoxic potential reduction; however, treated leachate still possessed genotoxic character.

The Comet Assay for the Evaluation of Genotoxic Potential of Landfill Leachate

PubMed Central

Widziewicz, Kamila; Kalka, Joanna; Skonieczna, Magdalena; Madej, Paweł

2012-01-01

Genotoxic assessment of landfill leachate before and after biological treatment was conducted with two human cell lines (Me45 and NHDF) and Daphnia magna somatic cells. The alkali version of comet assay was used to examine genotoxicity of leachate by DNA strand breaks analysis and its repair dynamics. The leachate samples were collected from Zabrze landfill, situated in the Upper Silesian Industrial District, Poland. Statistically significant differences (Kruskal-Wallice ANOVA rank model) were observed between DNA strand breaks in cells incubated with leachate before and after treatment (P < 0.001). Nonparametric Friedman ANOVA confirmed time-reliable and concentration-reliable cells response to leachate concentration. Examinations of chemical properties showed a marked decrease in leachate parameters after treatment which correlate to reduced genotoxicity towards tested cells. Obtained results demonstrate that biological cotreatment of leachate together with municipal wastewater is an efficient method for its genotoxic potential reduction; however, treated leachate still possessed genotoxic character. PMID:22666120

Assessing genotoxic effects in fish from a marine protected area influenced by former mining activities and other stressors.

PubMed

Gusso-Choueri, Paloma Kachel; Choueri, Rodrigo Brasil; Santos, Gustavo Souza; de Araújo, Giuliana Seraphim; Cruz, Ana Carolina Feitosa; Stremel, Tatiana; de Campos, Sandro Xavier; Cestari, Marta Margarete; Ribeiro, Ciro Alberto Oliveira; Abessa, Denis Moledo de Sousa

2016-03-15

The goal of the current study was to evaluate different genotoxicity tools in order to assess a marine protected area (MPA) affected by former mining activities and urban settlements. A catfish (Cathorops spixii) was analyzed for genotoxic effects at the (i) molecular and at the (ii) chromosomal levels. Through factor analysis, genotoxicity was found to be linked to levels of metals bioaccumulated and PAH metabolites in the bile. Micronucleus and nuclear alteration were less vulnerable to the effects of confounding factors in mildly contaminated areas since they were more frequently associated with bioaccumulated metals than the DNA analysis. The different genotoxicity responses allowed for the identification of sources of pollution in the MPA. This approach was important for detecting environmental risks related to genotoxic contaminants in a mildly contaminated MPA. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genotoxicity induced by metal oxide nanoparticles: a weight of evidence study and effect of particle surface and electronic properties.

PubMed

Golbamaki, Azadi; Golbamaki, Nazanin; Sizochenko, Natalia; Rasulev, Bakhtiyor; Leszczynski, Jerzy; Benfenati, Emilio

2018-06-09

The genetic toxicology of nanomaterials is a crucial toxicology issue and one of the least investigated topics. Substantially, the genotoxicity of metal oxide nanomaterials' data is resulting from in vitro comet assay. Current contributions to the genotoxicity data assessed by the comet assay provide a case-by-case evaluation of different types of metal oxides. The existing inconsistency in the literature regarding the genotoxicity testing data requires intelligent assessment strategies, such as weight of evidence evaluation. Two main tasks were performed in the present study. First, the genotoxicity data from comet assay for 16 noncoated metal oxide nanomaterials with different core composition were collected. An evaluation criterion was applied to establish which of these individual lines of evidence were of sufficient quality and what weight could have been given to them in inferring genotoxic results. The collected data were surveyed on (1) minimum necessary characterization points for nanomaterials and (2) principals of correct comet assay testing for nanomaterials. Second, in this study the genotoxicity effect of metal oxide nanomaterials was investigated by quantitative nanostructure-activity relationship approach. A set of quantum-chemical descriptors was developed for all investigated metal oxide nanomaterials. A classification model based on decision tree was developed for the investigated dataset. Thus, three descriptors were identified as the most responsible factors for genotoxicity effect: heat of formation, molecular weight, and surface area of the oxide cluster based on the conductor-like screening model. Conclusively, the proposed genotoxicity assessment strategy is useful to prioritize the study of the nanomaterials for further risk assessment evaluations.

Development of a Fish Cell Biosensor System for Genotoxicity Detection Based on DNA Damage-Induced Trans-Activation of p21 Gene Expression

PubMed Central

Geng, Deyu; Zhang, Zhixia; Guo, Huarong

2012-01-01

p21CIP1/WAF1 is a p53-target gene in response to cellular DNA damage. Here we report the development of a fish cell biosensor system for high throughput genotoxicity detection of new drugs, by stably integrating two reporter plasmids of pGL3-p21-luc (human p21 promoter linked to firefly luciferase) and pRL-CMV-luc (CMV promoter linked to Renilla luciferase) into marine flatfish flounder gill (FG) cells, referred to as p21FGLuc. Initial validation of this genotoxicity biosensor system showed that p21FGLuc cells had a wild-type p53 signaling pathway and responded positively to the challenge of both directly acting genotoxic agents (bleomycin and mitomycin C) and indirectly acting genotoxic agents (cyclophosphamide with metabolic activation), but negatively to cyclophosphamide without metabolic activation and the non-genotoxic agents ethanol and D-mannitol, thus confirming a high specificity and sensitivity, fast and stable response to genotoxic agents for this easily maintained fish cell biosensor system. This system was especially useful in the genotoxicity detection of Di(2-ethylhexyl) phthalate (DEHP), a rodent carcinogen, but negatively reported in most non-mammalian in vitro mutation assays, by providing a strong indication of genotoxicity for DEHP. A limitation for this biosensor system was that it might give false positive results in response to sodium butyrate and any other agents, which can trans-activate the p21 gene in a p53-independent manner. PMID:25585933

Application of the TGx‐28.65 transcriptomic biomarker to classify genotoxic and non‐genotoxic chemicals in human TK6 cells in the presence of rat liver S9

PubMed Central

Buick, Julie K.; Williams, Andrew; Swartz, Carol D.; Recio, Leslie; Li, Heng‐Hong; Fornace, Albert J.; Thomson, Errol M.; Aubrecht, Jiri

2016-01-01

In vitro transcriptional signatures that predict toxicities can facilitate chemical screening. We previously developed a transcriptomic biomarker (known as TGx‐28.65) for classifying agents as genotoxic (DNA damaging) and non‐genotoxic in human lymphoblastoid TK6 cells. Because TK6 cells do not express cytochrome P450s, we confirmed accurate classification by the biomarker in cells co‐exposed to 1% 5,6 benzoflavone/phenobarbital‐induced rat liver S9 for metabolic activation. However, chemicals may require different types of S9 for activation. Here we investigated the response of TK6 cells to higher percentages of Aroclor‐, benzoflavone/phenobarbital‐, or ethanol‐induced rat liver S9 to expand TGx‐28.65 biomarker applicability. Transcriptional profiles were derived 3 to 4 hr following a 4 hr co‐exposure of TK6 cells to test chemicals and S9. Preliminary studies established that 10% Aroclor‐ and 5% ethanol‐induced S9 alone did not induce the TGx‐28.65 biomarker genes. Seven genotoxic and two non‐genotoxic chemicals (and concurrent solvent and positive controls) were then tested with one of the S9s (selected based on cell survival and micronucleus induction). Relative survival and micronucleus frequency was assessed by flow cytometry in cells 20 hr post‐exposure. Genotoxic/non‐genotoxic chemicals were accurately classified using the different S9s. One technical replicate of cells co‐treated with dexamethasone and 10% Aroclor‐induced S9 was falsely classified as genotoxic, suggesting caution in using high S9 concentrations. Even low concentrations of genotoxic chemicals (those not causing cytotoxicity) were correctly classified, demonstrating that TGx‐28.65 is a sensitive biomarker of genotoxicity. A meta‐analysis of datasets from 13 chemicals supports that different S9s can be used in TK6 cells, without impairing classification using the TGx‐28.65 biomarker. Environ. Mol. Mutagen. 57:243–260, 2016. © 2016 Her Majesty the Queen in Right of Canada. Environmental and Molecular Mutagenesis © 2016 Environmental Mutagen Society PMID:26946220

Genotoxicity testing: progress and prospects for the next decade.

PubMed

Turkez, Hasan; Arslan, Mehmet E; Ozdemir, Ozlem

2017-10-01

Genotoxicity and mutagenicity analyses have a significant role in the identification of hazard effects of therapeutic drugs, cosmetics, agrochemicals, industrial compounds, food additives, natural toxins and nanomaterials for regulatory purposes. To evaluate mutagenicity or genotoxicity, different in vitro and in vivo methodologies exert various genotoxicological endpoints such as point mutations, changes in number and structure of chromosomes. Areas covered: This review covered the basics of genotoxicity and in vitro/in vivo methods for determining of genetic damages. The limitations that have arisen as a result of the common use of these methods were also discussed. Finally, the perspectives of further prospects on the use of genotoxicity testing and genotoxic mode of action were emphasized. Expert opinion: The solution of actual and practical problems of genetic toxicology is inarguably based on the understanding of DNA damage mechanisms at molecular, subcellular, cellular, organ, system and organism levels. Current strategies to investigate human health risks should be modified to increase their performance for more reliable results and also new techniques such as toxicogenomics, epigenomics and single cell approaches must be integrated into genetic safety evolutions. The explored new biomarkers by the omic techniques will provide forceful genotoxicity assessment to reduce the cancer risk.

Granular Activated Carbon Treatment May Result in Higher Predicted Genotoxicity in the Presence of Bromide.

PubMed

Krasner, Stuart W; Lee, Tiffany Chih Fen; Westerhoff, Paul; Fischer, Natalia; Hanigan, David; Karanfil, Tanju; Beita-Sandí, Wilson; Taylor-Edmonds, Liz; Andrews, Robert C

2016-09-06

Certain unregulated disinfection byproducts (DBPs) are more of a health concern than regulated DBPs. Brominated species are typically more cytotoxic and genotoxic than their chlorinated analogs. The impact of granular activated carbon (GAC) on controlling the formation of regulated and selected unregulated DBPs following chlorine disinfection was evaluated. The predicted cyto- and genotoxicity of DBPs was calculated using published potencies based on the comet assay for Chinese hamster ovary cells (assesses the level of DNA strand breaks). Additionally, genotoxicity was measured using the SOS-Chromotest (detects DNA-damaging agents). The class sum concentrations of trihalomethanes, haloacetic acids, and unregulated DBPs, and the SOS genotoxicity followed the breakthrough of dissolved organic carbon (DOC), however the formation of brominated species did not. The bromide/DOC ratio was higher than the influent through much of the breakthrough curve (GAC does not remove bromide), which resulted in elevated brominated DBP concentrations in the effluent. Based on the potency of the haloacetonitriles and halonitromethanes, these nitrogen-containing DBPs were the driving agents of the predicted genotoxicity. GAC treatment of drinking or reclaimed waters with appreciable levels of bromide and dissolved organic nitrogen may not control the formation of unregulated DBPs with higher genotoxicity potencies.

METHYLATED ASIII COMPOUNDS AS POTENTIAL PROXIMATE/ULTIMATE GENOTOXIC METABOLITES OF INORGANIC ARSENIC

EPA Science Inventory

METHYLATED Asm COMPOUNDS AS POTENTIAL PROXIMATE/ULTIMATE GENOTOXIC METABOLITES OF INORGANIC ARSENIC.

The methylation of inorganic arsenic has typically been viewed as a detoxification process. Genotoxicity tests have generally shown that arsenite has greater mutagenic p...

JaCVAM-organized international validation study of the in vivo rodent alkaline comet assay for detection of genotoxic carcinogens: II. Summary of definitive validation study results.

PubMed

Uno, Yoshifumi; Kojima, Hajime; Omori, Takashi; Corvi, Raffaella; Honma, Masamistu; Schechtman, Leonard M; Tice, Raymond R; Beevers, Carol; De Boeck, Marlies; Burlinson, Brian; Hobbs, Cheryl A; Kitamoto, Sachiko; Kraynak, Andrew R; McNamee, James; Nakagawa, Yuzuki; Pant, Kamala; Plappert-Helbig, Ulla; Priestley, Catherine; Takasawa, Hironao; Wada, Kunio; Wirnitzer, Uta; Asano, Norihide; Escobar, Patricia A; Lovell, David; Morita, Takeshi; Nakajima, Madoka; Ohno, Yasuo; Hayashi, Makoto

2015-07-01

The in vivo rodent alkaline comet assay (comet assay) is used internationally to investigate the in vivo genotoxic potential of test chemicals. This assay, however, has not previously been formally validated. The Japanese Center for the Validation of Alternative Methods (JaCVAM), with the cooperation of the U.S. NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM)/the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), the European Centre for the Validation of Alternative Methods (ECVAM), and the Japanese Environmental Mutagen Society/Mammalian Mutagenesis Study Group (JEMS/MMS), organized an international validation study to evaluate the reliability and relevance of the assay for identifying genotoxic carcinogens, using liver and stomach as target organs. The ultimate goal of this exercise was to establish an Organisation for Economic Co-operation and Development (OECD) test guideline. The study protocol was optimized in the pre-validation studies, and then the definitive (4th phase) validation study was conducted in two steps. In the 1st step, assay reproducibility was confirmed among laboratories using four coded reference chemicals and the positive control ethyl methanesulfonate. In the 2nd step, the predictive capability was investigated using 40 coded chemicals with known genotoxic and carcinogenic activity (i.e., genotoxic carcinogens, genotoxic non-carcinogens, non-genotoxic carcinogens, and non-genotoxic non-carcinogens). Based on the results obtained, the in vivo comet assay is concluded to be highly capable of identifying genotoxic chemicals and therefore can serve as a reliable predictor of rodent carcinogenicity. Copyright © 2015 Elsevier B.V. All rights reserved.

Revision of OECD Guidelines for Genotoxicity Testing: Current Status and Next Steps

EPA Science Inventory

Over the past 30 years, assays have been developed to evaluate chemical genotoxicity. OECD Genotoxicity Test Guidelines (TG) describe assay procedures for regulatory safety testing. Since the last OECD TG revision (1997), there has been tremendous scientific and technological pro...

Environmental genotoxicity and cytotoxicity in flounder (Platichthys flesus), herring (Clupea harengus) and Atlantic cod (Gadus morhua) from chemical munitions dumping zones in the southern Baltic Sea.

PubMed

Baršienė, Janina; Butrimavičienė, Laura; Grygiel, Wlodzimierz; Lang, Thomas; Michailovas, Aleksandras; Jackūnas, Tomas

2014-05-01

The data on environmental genotoxicity and cytotoxicity levels as well as on genotoxicity risk in flounder (Platichthys flesus), herring (Clupea harengus) and cod (Gadus morhua) collected in 2010-2012 at 42 stations located in chemical munitions dumping areas of the southern Baltic Sea are presented. The frequency of micronuclei, nuclear buds and nucleoplasmic bridges in erythrocytes was used as genotoxicity endpoint and the induction of fragmented-apoptotic, bi-nucleated and 8-shaped erythrocytes as cytotoxicity endpoint. The most significantly increased geno-cytotoxicity levels were determined in fish collected near known chemical munitions dumpsites. Extremely high genotoxicity risk for flounder were identified at 21 out of 24 stations, for herring at 29 out of 31 and for cod at 5 out of 10 stations studied. The reference level of genotoxicity was not recorded at any of the stations revealing that in the sampling area fish were affected generally. Copyright © 2013 Elsevier Ltd. All rights reserved.

Transcriptional activation of short interspersed elements by DNA-damaging agents.

PubMed

Rudin, C M; Thompson, C B

2001-01-01

Short interspersed elements (SINEs), typified by the human Alu repeat, are RNA polymerase III (pol III)-transcribed sequences that replicate within the genome through an RNA intermediate. Replication of SINEs has been extensive in mammalian evolution: an estimated 5% of the human genome consists of Alu repeats. The mechanisms regulating transcription, reverse transcription, and reinsertion of SINE elements in genomic DNA are poorly understood. Here we report that expression of murine SINE transcripts of both the B1 and B2 classes is strongly upregulated after prolonged exposure to cisplatin, etoposide, or gamma radiation. A similar induction of Alu transcripts in human cells occurs under these conditions. This induction is not due to a general upregulation of pol III activity in either species. Genotoxic treatment of murine cells containing an exogenous human Alu element induced Alu transcription. Concomitant with the increased expression of SINEs, an increase in cellular reverse transcriptase was observed after exposure to these same DNA-damaging agents. These findings suggest that genomic damage may be an important activator of SINEs, and that SINE mobility may contribute to secondary malignancy after exposure to DNA-damaging chemotherapy.

The Mitochondrial DNA-Associated Protein SWIB5 Influences mtDNA Architecture and Homologous Recombination[OPEN

PubMed Central

Vercruysse, Jasmien; Van Daele, Twiggy; De Milde, Liesbeth; Benhamed, Moussa; Inzé, Dirk

2017-01-01

In addition to the nucleus, mitochondria and chloroplasts in plant cells also contain genomes. Efficient DNA repair pathways are crucial in these organelles to fix damage resulting from endogenous and exogenous factors. Plant organellar genomes are complex compared with their animal counterparts, and although several plant-specific mediators of organelle DNA repair have been reported, many regulators remain to be identified. Here, we show that a mitochondrial SWI/SNF (nucleosome remodeling) complex B protein, SWIB5, is capable of associating with mitochondrial DNA (mtDNA) in Arabidopsis thaliana. Gain- and loss-of-function mutants provided evidence for a role of SWIB5 in influencing mtDNA architecture and homologous recombination at specific intermediate-sized repeats both under normal and genotoxic conditions. SWIB5 interacts with other mitochondrial SWIB proteins. Gene expression and mutant phenotypic analysis of SWIB5 and SWIB family members suggests a link between organellar genome maintenance and cell proliferation. Taken together, our work presents a protein family that influences mtDNA architecture and homologous recombination in plants and suggests a link between organelle functioning and plant development. PMID:28420746

[DNA tandem lesion: 5',8-cyclo-2'-deoxyadenosine. The influence on human health].

PubMed

Merecz, A; Karwowski, B T

2016-01-01

Nucleic acids are the targets for various endogenous and exogenous genotoxic agents, including reactive oxygen species. The appearance of a hydroxyl racial (^(.)OH), the most harmful molecule, next to an oligonucleotide can lead to two types of DNA damage: strand breaks or nucleobase modifications. Since clustered DNA damage is defined as the presence of two or more lesions in one helix turn, purine 5',8-cyclo-2'-deoxynucleosides are recognized as tandem lesions: both sugar moieties and base have been modified within one nucleoside/nucleotide. The hydrogen abstraction from the C5' group of nucleosides/nucleotides by ^(.)OH, with subsequent C8 C5' cyclisation results in purine 5',8-cyclonucleoside formation. Due to its unusual 3D structure and the fact that only one radical hit is needed for purine 5',8-cyclonucleoside formation their influence on genome stability/integrity and DNA repair processes are subjects of medical interest. In the present work the influence of 5',8-cyclo-2'-deoxyadenosine on DNA spatial geometry and DNA repair hinder in connection with human health, such as neurological disorders is discussed.

Investigation of potential genotoxic activity using the SOS Chromotest for real paracetamol wastewater and the wastewater treated by the Fenton process.

PubMed

Kocak, Emel

2015-01-01

The potential genotoxic activity associated with high strength real paracetamol (PCT) wastewater (COD = 40,000 mg/L, TOC = 12,000 mg/L, BOD5 = 19,320 mg/L) from a large-scale drug-producing plant in the Marmara Region, was investigated in pre- and post- treated wastewater by the Fenton process (COD = 2,920 mg/L, TOC = 880 mg/L; BOD5 = 870 mg/L). The SOS Chromotest, which is based on Escherichia coli PQ37 activities, was used for the assessment of genotoxicity. The corrected induction factors (CIF) values used as quantitative measurements of the genotoxic activity were obtained from a total of four different dilutions (100, 50, 6.25, and 0.078 % v/v.) for two samples, in triplicate, to detect potentially genotoxic activities with the SOS Chromotest. The results of the SOS Chromotest demonstrated CIFmax value of 1.24, indicating that the PCT effluent (non-treated) is genotoxic. The results of the SOS Chromotest showed an CIFmax value of 1.72, indicating that the wastewater treated by Fenton process is genotoxic. The findings of this study clearly reveal that the PCT wastewater (non-treated) samples have a potentially hazardous impact on the aquatic environment before treatment, and in the wastewater that was treated by the Fenton process, genotoxicity generally increased.

The genotoxic contribution of wood smoke to indoor respirable suspended particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boone, P.M.; Rossman, T.G.; Daisey, J.M.

1989-01-01

The effect of wood burning stoves on the genotoxicity of indoor respirable organic matter was investigated for four homes during the winter and spring of 1986. Paired samples, one collected when the stove was not used and one when wood was burned, were extracted with dichloromethane and acetone. Aliquots of the dichloromethane extracts were analyzed with and without metabolic activation using the Microscreen bioassay. The Microscreen is a rapid, sensitive bioassay which measures a broad genotoxic endpoint, {lambda}-prophage induction. Per nanogram of organic material, wood smoke proved to be a major source of indirect (observed with metabolic activation) but notmore » direct genotoxins in homes. The increase in indirect genotoxicity for extracts from aerosol containing wood smoke is probably due to higher concentrations of polycyclic aromatic hydrocarbons in the wood smoke aerosol as well as other unidentified classes. The direct genotoxicity observed for extracts of aerosol not containing wood smoke decreased with metabolic activation. This direct genotoxicity may be related to cooking activities in the homes. The trends in genotoxicity observed per nanogram of organic material are more pronounced when expressed per m{sup 3} of air due to the higher percentage of extractable material in aerosol containing wood smoke.« less

Evaluating the Effects of Bioremediation on Genotoxicity of Polycyclic Aromatic Hydrocarbon-Contaminated Soil Using Genetically Engineered, Higher Eukaryotic Cell Lines

PubMed Central

Hu, Jing; Nakamura, Jun; Richardson, Stephen D.; Aitken, Michael D.

2012-01-01

Bioremediation is one of the commonly applied remediation strategies at sites contaminated with polycyclic aromatic hydrocarbons (PAHs). However, remediation goals are typically based on removal of the target contaminants rather than on broader measures related to health risks. We investigated changes in the toxicity and genotoxicity of PAH-contaminated soil from a former manufactured-gas plant site before and after two simulated bioremediation processes: a sequencing batch bioreactor system and a continuous-flow column system. Toxicity and genotoxicity of the residues from solvent extracts of the soil were determined by the chicken DT40 B-lymphocyte isogenic cell line and its DNA-repair-deficient mutants. Although both bioremediation processes significantly removed PAHs from the contaminated soil (bioreactor 69% removal; column 84% removal), bioreactor treatment resulted in an increase in toxicity and genotoxicity over the course of a treatment cycle, whereas long-term column treatment resulted in a decrease in toxicity and genotoxicity. However, when screening with a battery of DT40 mutants for genotoxicity profiling, we found that column treatment induced DNA damage types that were not observed in untreated soil. Toxicity and genotoxicity bioassays can supplement chemical analysis-based risk assessment for contaminated soil when evaluating the efficacy of bioremediation. PMID:22443351

Formation and removal of genotoxic activity during UV/H(2)O(2)-GAC treatment of drinking water.

PubMed

Heringa, M B; Harmsen, D J H; Beerendonk, E F; Reus, A A; Krul, C A M; Metz, D H; Ijpelaar, G F

2011-01-01

The objective of this study was to determine the genotoxic activity of water after UV/H(2)O(2) oxidation and GAC filtration. Pre-treated surface water from three locations was treated with UV/H(2)O(2) with medium pressure (MP) lamps and passed through granulated activated carbon (GAC). Samples taken before and after each treatment step were extracted and concentrated by solid phase extraction (SPE) and analyzed for genotoxicity using the Comet assay with HepG2 cells and the Ames II assay. The Comet assay showed no genotoxic response in any of the samples. In the Ames II, no genotoxic response was obtained with the TAMix (a mix of six strains), but the TA98 strain showed an increase in genotoxic activity after MP-UV/H(2)O(2) for all three locations. GAC post treatment effectively reduced the activities to control levels at two of the three locations and to below the level of the pre-treated water at one site. The results indicate that UV/H(2)O(2) treatment may lead to the formation of genotoxic by-products, which can be removed by subsequent GAC filtration. Copyright © 2010 Elsevier Ltd. All rights reserved.

Quantification of umu genotoxicity level of urban river water.

PubMed

Kameya, T; Nagato, T; Nakagawa, K; Yamashita, D; Kobayashi, T; Fujie, K

2011-01-01

In recent years, the request of environmental safety management for carcinogenic substances, mutagenic substances and/or reproductive toxicity substances (CMR) has increased. This study focused on clarifying the genotoxicity level of environmental water and its release source by using the umu test provided in ISO13829. Although a genotoxicity index "induction ratio (IR)" is used in ISO13829, we normalised it to make it possible to compare various environmental water quantitatively to each other as a new index "genotoxic activity (GA=(IR-1)/Dose)". Sample water was collected and concentrated to 100 times or 1,000 times by a solid phase extraction method. As the test results, it was found that GA level in actual river water varied widely from less than the determination limit of 23 [1/L] to 1,100 [1/L] by quantitative comparison, and the value was also equivalent to more than 50 times the level of tap water. The GA level of household wastewater was not so high, but the levels of treated water from wastewater treatment plant (WTP) were from 220 [1/L] to 3,200 [1/L]. Raw sewage of some WTP shows high level genotoxicity. A part of genotoxicity substances, for example 50%, could be removed by conventional wastewater treatment, but it was not enough to reduce the water environmental load of genotoxicity.

Alumina at 50 and 13 nm nanoparticle sizes have potential genotoxicity.

PubMed

Zhang, Qinli; Wang, Haiyang; Ge, Cuicui; Duncan, Jeremy; He, Kaihong; Adeosun, Samuel O; Xi, Huaxin; Peng, Huiting; Niu, Qiao

2017-09-01

Although nanomaterials have the potential to improve human life, their sideline effects on human health seem to be inevitable and still are unknown. Some studies have investigated the genotoxicity of alumina nanoparticles (AlNPs); however, this effect is still unclear due to insufficient evaluation and conflicting results. Using a battery of standard genotoxic assays, the present study offers evidence of the genotoxicity associated with aluminum oxide (alumina) at NP sizes of 50 and 13 nm, when compared with bulk alumina (10 μm). The genotoxicity induced by alumina at bulk and NP sizes was evaluated with Ames test, comet test, micronucleus assay and sperm deformity test. The mechanism related to the induction of reactive oxygen species was explored as well. Our results showed that AlNPs (13 and 50 nm) were able to enter cells and induced DNA damage, micronucleus in bone marrow, sperm deformation and reactive oxygen species induction in a time-, dose- and size-dependent manner. Therefore, we conclude that AlNPs (13 and 50 nm), rather than bulk alumina, induce markers of genotoxicity in mice, with oxidative stress as a potential mechanism driving these genotoxic effects. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

6-gingerol prevents patulin-induced genotoxicity in HepG2 cells.

PubMed

Yang, Guang; Zhong, Laifu; Jiang, Liping; Geng, Chengyan; Cao, Jun; Sun, Xiance; Liu, Xiaofang; Chen, Min; Ma, Yufang

2011-10-01

Patulin (PAT) is a mycotoxin produced by several Penicillium, Aspergillus and Byssochlamys species. Since PAT is a potent genotoxic compound, and PAT contamination is common in fruits and fruit products, the search for newer, better agents for protection against genotoxicity of PAT is required. In this study, the chemoprotective effect of 6-gingerol against PAT-induced genotoxicity in HepG2 cells was investigated. The comet assay and micronucleus test (MNT) were used to monitor genotoxic effects. To further elucidate the underlying mechanisms, the intracellular generation of reactive oxygen species (ROS) and level of reduced glutathione (GSH) were tested. In addition, the level of oxidative DNA damage was evaluated by immunocytochemical analysis of 8-hydroxydeoxyguanosine (8-OHdG). The results showed that 6-gingerol significantly reduced the DNA strand breaks and micronuclei formation caused by PAT. Moreover, 6-gingerol effectively suppressed PAT-induced intracellular ROS formation and 8-OHdG level. The GSH depletion induced by PAT in HepG2 cells was also attenuated by 6-gingerol pretreatment. These findings suggest that 6-gingerol has a strong protective ability against the genotoxicity caused by PAT, and the antioxidant activity of 6-gingerol may play an important part in attenuating the genotoxicity of PAT. Copyright © 2011 John Wiley & Sons, Ltd.

How to assess the mutagenic potential of cosmetic products without animal tests?

PubMed

Speit, Günter

2009-08-01

Animal experiments (in vivo tests) currently play a key role in genotoxicity testing. Results from in vivo tests are, in many cases, decisive for the assessment of a mutagenic potential of a test compound. The Seventh Amendment to the European Cosmetics Directive will, however, ban the European marketing of cosmetic/personal care products that contain ingredients that have been tested in animal experiments. If genotoxicity testing is solely based on the currently established in vitro tests, the attrition rate for chemicals used in cosmetic products will greatly increase due to irrelevant positive in vitro test results. There is urgent need for new and/or improved in vitro genotoxicity tests and for modified test strategies. Test strategies should consider all available information on chemistry of the test substance/the chemical class (e.g. SAR, metabolic activation and dermal adsorption). Test protocols for in vitro genotoxicity tests should be sensitive and robust enough to ensure that negative results can be accepted with confidence. It should be excluded that positive in vitro test results are due to high cytotoxicity or secondary genotoxic effects which may be thresholded and/or only occur under in vitro test conditions. Consequently, further research is needed to establish the nature of thresholds in in vitro assays and to determine the potential for incorporation of mode of action data into future risk assessments. New/improved tests have to be established and validated, considering the use of (metabolically competent) primary (skin) cells, 3D skin models and cells with defined capacity for metabolic activation (e.g. genetically engineered cell lines). The sensitivity and specificity of new and improved genotoxicity tests has to be determined by testing a battery of genotoxic and non-genotoxic chemicals. New or adapted international guidelines will be needed for these tests. The establishment of such a new genotoxicity testing strategy will take time and the new in vitro genotoxicity testing will become much more complex and will require greater mechanistic understanding to build a weight of evidence decision, which will be demanding and time-consuming. At present, no validated alternative methods for the follow-up of positive results from the standard genotoxicity battery are available and an appropriate evaluation of the mutagenic potential of cosmetic ingredients without animal experiments is therefore not possible in many cases.

Diet-induced obesity increases the frequency of Pig-a mutant erythrocytes in male C57BL/6J mice.

PubMed

Wickliffe, Jeffrey K; Dertinger, Stephen D; Torous, Dorothea K; Avlasevich, Svetlana L; Simon-Friedt, Bridget R; Wilson, Mark J

2016-12-01

Obesity increases the risk of a number of chronic diseases in humans including several cancers. Biological mechanisms responsible for such increased risks are not well understood at present. Increases in systemic inflammation and oxidative stress, endogenous production of mutagenic metabolites, altered signaling in proliferative pathways, and increased sensitivity to exogenous mutagens and carcinogens are some of the potential contributing factors. We hypothesize that obesity creates an endogenously mutagenic environment in addition to increasing the sensitivity to environmental mutagens. To test this hypothesis, we examined two in vivo genotoxicity endpoints. Pig-a mutant frequencies and micronucleus frequencies were determined in blood cells in two independent experiments in 30-week old male mice reared on either a high-fat diet (60% calories from fat) that exhibit an obese phenotype or a normal-fat diet (10% calories from fat) that do not exhibit an obese phenotype. Mice were assayed again at 52 weeks of age in one of the experiments. N-ethyl-N-nitrosourea (ENU) was used as a positive mutation control in one experiment. ENU induced a robust Pig-a mutant and micronucleus response in both phenotypes. Obese, otherwise untreated mice, did not differ from non-obese mice with respect to Pig-a mutant frequencies in reticulocytes or micronucleus frequencies. However, such mice, had significantly higher and sustained Pig-a mutant frequencies (increased 2.5-3.7-fold, p < 0.02) in erythrocytes as compared to non-obese mice (based on measurements collected at 30 weeks or 30 and 52 weeks of age). This suggests that obesity, in the absence of exposure to an exogenous mutagen, is itself mutagenic. Environ. Mol. Mutagen. 57:668-677, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

The carcinogenic action of crystalline silica: a review of the evidence supporting secondary inflammation-driven genotoxicity as a principal mechanism.

PubMed

Borm, Paul J A; Tran, Lang; Donaldson, Ken

2011-10-01

In 1987 the International Agency for Research on Cancer (IARC) classified crystalline silica (CS) as a probable carcinogen and in 1997 reclassified it as a Group 1 carcinogen, i.e., that there was sufficient evidence for carcinogenicity in experimental animals and sufficient evidence for carcinogenicity in humans. The Working Group noted that "carcinogenicity in humans was not detected in all industrial circumstances studied, carcinogenicity may be dependent on inherent characteristics of the crystalline silica or on external factors affecting its biological activity or distribution of its polymorphs." This unusual statement that the physicochemical form of the CS influences its carcinogenicity is well understood at the toxicological level and arises as a consequence of the fact that CS activity depends on the reactivity of the CS surface, which can be blocked by a number of agents. We reviewed the literature on CS genotoxicity that has been published since the 1997 monograph, with special reference to the mechanism of CS genotoxicity. The mechanism of CS genotoxicity can be primary, a result of direct interaction of CS with target cells, or indirect, as a consequence of inflammation elicited by quartz, where the inflammatory cell-derived oxidants cause the genotoxicity. The review revealed a number of papers supporting the hypothesis that the CS genotoxic and inflammatory hazard is a variable one. In an attempt to attain a quantitative basis for the potential mechanism, we carried out analysis of published data and noted a 5-fold greater dose required to reach a threshold for genotoxic effects than for proinflammatory effects in the same cell line in vitro. When we related the calculated threshold dose at the proximal alveolar region for inflammation in a published study with the threshold dose for genotoxicity in vitro, we noted that a 60-120-fold greater dose was required for direct genotoxic effects in vitro. These data strongly suggests that inflammation is the driving force for genotoxicity and that primary genotoxicity of deposited CS would play a role only at very high, possibly implausible, exposures and deposited doses. Although based on rat studies and in vitro studies, and therefore with caveats, the analysis supports the hypothesis that the mechanism of CS genotoxicity is via inflammation-driven secondary genotoxicity. This may have implications for setting of the CS standard in workplaces. During the writing of this review (in May 2009), IARC undertook a review of carcinogenic substances, including CS. The Working Group met to reassess 10 separate agents including CS. This was not a normal monograph working group published as a large single monograph, but was published as a two-page report. This review group reaffirmed the carcinogenicity of "silica dust, crystalline in the form of quartz or cristobalite" as a Group 1 agent, with the lung as the sole tumor site. Of special relevance to the present review is that the cited "established mechanism events" for CS are restricted to the words "impaired particle clearance leading to macrophage activation and persistent inflammation." The lack of mention of direct genotoxicity is in line with the conclusions reached in the present review.

Detection of genotoxic and non-genotoxic carcinogens in Xpc{sup −/−}p53{sup +/−} mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melis, Joost P.M.; Leiden University Medical Center, Department of Toxicogenetics, Leiden; Speksnijder, Ewoud N.

2013-01-15

An accurate assessment of the carcinogenic potential of chemicals and pharmaceutical drugs is essential to protect humans and the environment. Therefore, substances are extensively tested before they are marketed to the public. Currently, the rodent two-year bioassay is still routinely used to assess the carcinogenic potential of substances. However, over time it has become clear that this assay yields false positive results and also has several economic and ethical drawbacks including the use of large numbers of animals, the long duration, and the high cost. The need for a suitable alternative assay is therefore high. Previously, we have proposed themore » Xpa*p53 mouse model as a very suitable alternative to the two-year bioassay. We now show that the Xpc*p53 mouse model preserves all the beneficial traits of the Xpa*p53 model for sub-chronic carcinogen identification and can identify both genotoxic and non-genotoxic carcinogens. Moreover, Xpc*p53 mice appear to be more responsive than Xpa*p53 mice towards several genotoxic and non-genotoxic carcinogens. Furthermore, Xpc*p53 mice are far less sensitive than Xpa*p53 mice for the toxic activity of DNA damaging agents and as such clearly respond in a similar way as wild type mice do. These advantageous traits of the Xpc*p53 model make it a better alternative for in vivo carcinogen testing than Xpa*p53. This pilot study suggests that Xpc*p53 mice are suited for routine sub-chronic testing of both genotoxic and non-genotoxic carcinogens and as such represent a suitable alternative to possibly replace the murine life time cancer bioassay. Highlights: ► The Xpc*p53 mouse model is able to identify genotoxic and non-genotoxic carcinogens. ► Time, animals and cost can be significantly reduced compared to the 2-year bioassay. ► Xpc*p53 mice are more advantageous for carcinogen identification than Xpa*p53 mice. ► Xpc*p53 mice exhibit a wild type response upon exposure to genotoxicants.« less

Genotoxicity of antiobesity drug orlistat and effect of caffeine intervention: an in vitro study.

PubMed

Chakrabarti, Manoswini; Ghosh, Ilika; Jana, Aditi; Ghosh, Manosij; Mukherjee, Anita

2017-07-01

Obesity is a major global health problem associated with various adverse effects. Pharmacological interventions are often necessary for the management of obesity. Orlistat is an FDA-approved antiobesity drug which is a potent inhibitor of intestinal lipases. In the current study, orlistat was evaluated for its genotoxic potential in human lymphocyte cells in vitro and was compared with that of another antiobesity drug sibutramine, presently withdrawn from market due its undesirable health effects. Caffeine intake may be an additional burden in people using anorectic drugs, therefore, further work is needed to be carried out to evaluate the possible effects of caffeine on orlistat-induced DNA damage. Human lymphocytes were exposed to orlistat (250, 500 and 1000 μg/ml), sibutramine (250, 500 and 1000 μg/ml) and caffeine (25, 50, 75, 100, 125 and 150 μg/ml) to assess their genotoxicity by comet assay in vitro. In addition, lymphocytes were co-incubated with caffeine (50, 75 and 100 μg/ml) and a single concentration of orlistat (250 μg/ml). Orlistat and sibutramine were genotoxic at all concentrations tested, sibutramine being more genotoxic. Caffeine was found to be genotoxic at concentrations 125 μg/ml and above. Co-treatment of orlistat with non-genotoxic concentrations (50, 75 and 100 μg/ml) of caffeine lead to a decrease in DNA damage. Orlistat can induce DNA damage in human lymphocytes in vitro and caffeine was found to reduce orlistat-induced genotoxicity.

Genotoxic substances in the St. Lawrence system. 1: Industrial genotoxins sorbed to particulate matter in the St. Lawrence, St. Maurice, and Saguenay rivers, Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, P.A.; Rasmussen, J.B.; Blaise, C.

1998-02-01

Previous investigations of organic genotoxins in industrial effluents discharged into the St. Lawrence River system (Quebec, Canada) indicated that a substantial fraction of the genotoxicity is adsorbed to suspended particulate matter. This study used the SOS Chromotest to investigate the presence, potency, and behavior of particle-bound genotoxins in the downstream ecosystem. The results indicate that although extracts of both suspended and sedimented particulate matter are genotoxic, suspended particulate matter samples are more potent in the absence of S9 activation, with the reverse being true for bottom sediments. The results confirmed a positive relationship between the genotoxicity of bottom sediment extractsmore » and sediment organic matter content. A similar relationship between organic matter content and total polycyclic aromatic hydrocarbon (PAH) concentration indicates that putative genotoxins have physicochemical properties similar to the PAH class of contaminants. Conversion of PAH values to benzo[a]pyrene equivalents indicates that measured PAHs only account for a small fraction ({approximately}10%) of the observed SOS Chromotest response. Sites that receive discharges from foundries, aluminum refineries, and petroleum refineries yielded several of the most genotoxic samples. Further analyses revealed that the genotoxicity of suspended and sedimented particulate matter extracts is empirically related to the genotoxicity of industrial discharges. Comparisons of total genotoxicity levels in suspended particulates and bottom sediments suggest that direct-acting substances adsorbed to suspended matter are rapidly degraded and/or converted to more stable progenotoxins upon deposition. Further research is required to test this hypothesis and investigate effects on indigenous biota.« less

Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in HL-60 cells are not reproducible.

PubMed

Speit, Günter; Gminski, Richard; Tauber, Rudolf

2013-08-15

Conflicting results have been published regarding the induction of genotoxic effects by exposure to radiofrequency electromagnetic fields (RF-EMF). Various results indicating a genotoxic potential of RF-EMF were reported by the collaborative EU-funded REFLEX (Risk Evaluation of Potential Environmental Hazards From Low Energy Electromagnetic Field Exposure Using Sensitive in vitro Methods) project. There has been a long-lasting scientific debate about the reliability of the reported results and an attempt to reproduce parts of the results obtained with human fibroblasts failed. Another part of the REFLEX study was performed in Berlin with the human lymphoblastoid cell line HL-60; genotoxic effects of RF-EMF were measured by means of the comet assay and the micronucleus test. The plausibility and reliability of these results were also questioned. In order to contribute to a clarification of the biological significance of the reported findings, a repeat study was performed, involving scientists of the original study. Comet-assay experiments and micronucleus tests were performed under the same experimental conditions that had led to genotoxic effects in the REFLEX study. Here we report that the attempts to reproduce the induction of genotoxic effects by RF-EMF in HL-60 cells failed. No genotoxic effects of RF-EMF were measured in the repeat experiments. We could not find an explanation for the conflicting results. However, the negative repeat experiments suggest that the biological significance of genotoxic effects of RF-EMF reported by the REFLEX study should be re-assessed. Copyright © 2013 Elsevier B.V. All rights reserved.

Genotoxicity investigations on nanomaterials.

PubMed

Oesch, Franz; Landsiedel, Robert

2012-07-01

This review is based on the lecture presented at the April 2010 nanomaterials safety assessment Postsatellite to the 2009 EUROTOX Meeting and summarizes genotoxicity investigations on nanomaterials published in the open scientific literature (up to 2008). Special attention is paid to the relationship between particle size and positive versus negative outcome, as well as the dependence of the outcome on the test used. Salient conclusions and outstanding recommendations emerging from the information summarized in this review are as follows: recognize that nanomaterials are not all the same; therefore know and document what nanomaterial has been tested and in what form; take nanomaterials specific properties into account; in order to make your results comparable with those of others and on other nanomaterials: use or at least include in your studies standardized methods; use in vivo studies to put in vitro results into perspective; take uptake and distribution of the nanomaterial into account; and in order to become able to make extrapolations to risk for human: learn about the mechanism of nanomaterials genotoxic effects. Past experience with standard non-nanosubstances already had shown that mechanisms of genotoxic effects can be complex and their elucidation can be demanding, while there often is an immediate need to assess the genotoxic hazard. Thus, a practical and pragmatic approach to genotoxicity investigations of novel nanomaterials is the use of a battery of standard genotoxicity testing methods covering a wide range of mechanisms. Application of these standard methods to nanomaterials demands, however, adaptations, and the interpretation of results from the genotoxicity testing of nanomaterials needs additional considerations exceeding those used for standard size materials.

The cytotoxicity and genotoxicity of soluble and particulate cobalt in human lung fibroblast cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Leah J.; Holmes, Amie L.; Maine Center for Environmental Toxicology and Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04101-9300

Cobalt exposure is increasing as cobalt demand rises worldwide due to its use in enhancing rechargeable battery efficiency, super-alloys, and magnetic products. Cobalt is considered a possible human carcinogen with the lung being a primary target. However, few studies have considered cobalt-induced toxicity in human lung cells. Therefore, in this study, we sought to determine the cytotoxicity and genotoxicity of particulate and soluble cobalt in human lung cells. Cobalt oxide and cobalt chloride were used as representative particulate and soluble cobalt compounds, respectively. Exposure to both particulate and soluble cobalt induced a concentration-dependent increase in cytotoxicity, genotoxicity, and intracellular cobaltmore » ion levels. Based on intracellular cobalt ion levels, we found that soluble cobalt was more cytotoxic than particulate cobalt while particulate and soluble cobalt induced similar levels of genotoxicity. However, soluble cobalt induced cell cycle arrest indicated by the lack of metaphases at much lower intracellular cobalt concentrations compared to cobalt oxide. Accordingly, we investigated the role of particle internalization in cobalt oxide-induced toxicity and found that particle-cell contact was necessary to induce cytotoxicity and genotoxicity after cobalt exposure. These data indicate that cobalt compounds are cytotoxic and genotoxic to human lung fibroblasts, and solubility plays a key role in cobalt-induced lung toxicity. - Highlights: • Particulate and soluble cobalt are cytotoxic and genotoxic to human lung cells. • Soluble cobalt induces more cytotoxicity compared to particulate cobalt. • Soluble and particulate cobalt induce similar levels of genotoxicity. • Particle-cell contact is required for particulate cobalt-induced toxicity.« less

A whole-cell bioreporter assay for quantitative genotoxicity evaluation of environmental samples.

PubMed

Jiang, Bo; Li, Guanghe; Xing, Yi; Zhang, Dayi; Jia, Jianli; Cui, Zhisong; Luan, Xiao; Tang, Hui

2017-10-01

Whole-cell bioreporters have emerged as promising tools for genotoxicity evaluation, due to their rapidity, cost-effectiveness, sensitivity and selectivity. In this study, a method for detecting genotoxicity in environmental samples was developed using the bioluminescent whole-cell bioreporter Escherichia coli recA::luxCDABE. To further test its performance in a real world scenario, the E. coli bioreporter was applied in two cases: i) soil samples collected from chromium(VI) contaminated sites; ii) crude oil contaminated seawater collected after the Jiaozhou Bay oil spill which occurred in 2013. The chromium(VI) contaminated soils were pretreated by water extraction, and directly exposed to the bioreporter in two phases: aqueous soil extraction (water phase) and soil supernatant (solid phase). The results indicated that both extractable and soil particle fixed chromium(VI) were bioavailable to the bioreporter, and the solid-phase contact bioreporter assay provided a more precise evaluation of soil genotoxicity. For crude oil contaminated seawater, the response of the bioreporter clearly illustrated the spatial and time change in genotoxicity surrounding the spill site, suggesting that the crude oil degradation process decreased the genotoxic risk to ecosystem. In addition, the performance of the bioreporter was simulated by a modified cross-regulation gene expression model, which quantitatively described the DNA damage response of the E. coli bioreporter. Accordingly, the bioluminescent response of the bioreporter was calculated as the mitomycin C equivalent, enabling quantitative comparison of genotoxicities between different environmental samples. This bioreporter assay provides a rapid and sensitive screening tool for direct genotoxicity assessment of environmental samples. Copyright © 2017. Published by Elsevier Ltd.

GENOTOXICITY OF TEN CIGARETTE SMOKE CONDENSATES IN FOUR TEST SYSTEMS: COMPARISONS AMONG ASSAYS AND CONDENSATES

EPA Science Inventory

The particulate fraction of cigarette smoke, cigarette smoke condensate (CSC), is genotoxic in many short-term in vitro tests and carcinogenic in rodents. However, no study has evaluatedd a set of CSCs prepared from a diverse set of cigarettes in a variety of short-term genotoxic...

PROXIMATE OR ULTIMATE GENOTOXIC FORMS OF ARSENIC: METHYLATED ARSENIC(III) SPECIES THAT REACT DIRECTLY WITH DNA

EPA Science Inventory

PROXIMATE OR ULTIMATE GENOTOXIC FORMS OF ARSENIC: METHYLATED ARSENIC(III) SPECIES THAT REACT DIRECTL Y WITH DNA.

Abstract:

Although inorganic arsenic (iAs), arsenite or arsenate, is genotoxic, there has been no demonstration that iAs or a methylated metabolite...

OCCURRENCE, GENOTOXICITY, AND CARCINOGENICITY OF EMERGING DISINFECTION BY-PRODUCTS IN DRINKING WATER: A REVIEW AND ROADMAP FOR RESEARCH

EPA Science Inventory

Occurrence, Genotoxicity, and Carcinogenicity of Emerging Disinfection By-products in Drinking Water: A Review and Roadmap for Research
Summary of Paper
What is study?
This is the first review of the 30 year's research effort on the occurrence, genotoxicity,...

Environmental effects of dredging: Methods for the assessment of the genotoxic effects of environmental contaminants. Glossary and references. Technical notes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Honeycutt, M.E.; Jarvis, A.S.; McFarland, V.A.

1995-07-01

This technical note is the third in a series of three that outline and describe the principal methods that have been developed to test the potential of environmental contaminants to cause mutagenic, carcinogenic, and teratogenic effects. The first in this series (EEDP-04-24) describes methods used to discern genotoxic effects at the sub cellular level, while the second (EEDP-04-25) describes methods used to discern genotoxic effects at the cellular and organ/organism level. Recent literature citations for each topic referenced in this series of technical notes are provided in this technical note, in addition to a glossary of terms. The information inmore » these technical notes is intended to provide Corps of Engineers personnel with a working knowledge of the terminology and conceptual basis of genotoxicity testing. To develop an improved understanding of the concepts of genotoxicity, readers are encouraged to review A Primer in Genotoxicity (Jarvis, Reilly, and Lutz 1993), presented in Volume D-93-3 of the Environmental Effects of Dredging information exchange bulletin.« less

Genotoxicity of retroviral hematopoietic stem cell gene therapy

PubMed Central

Trobridge, Grant D

2012-01-01

Introduction Retroviral vectors have been developed for hematopoietic stem cell (HSC) gene therapy and have successfully cured X-linked severe combined immunodeficiency (SCID-X1), adenosine deaminase deficiency (ADA-SCID), adrenoleukodystrophy, and Wiskott-Aldrich syndrome. However, in HSC gene therapy clinical trials, genotoxicity mediated by integrated vector proviruses has led to clonal expansion, and in some cases frank leukemia. Numerous studies have been performed to understand the molecular basis of vector-mediated genotoxicity with the aim of developing safer vectors and safer gene therapy protocols. These genotoxicity studies are critical to advancing HSC gene therapy. Areas covered This review provides an introduction to the mechanisms of retroviral vector genotoxicity. It also covers advances over the last 20 years in designing safer gene therapy vectors, and in integration site analysis in clinical trials and large animal models. Mechanisms of retroviral-mediated genotoxicity, and the risk factors that contribute to clonal expansion and leukemia in HSC gene therapy are introduced. Expert opinion Continued research on virus–host interactions and next-generation vectors should further improve the safety of future HSC gene therapy vectors and protocols. PMID:21375467

Genotoxic effects of boric acid and borax in zebrafish, Danio rerio using alkaline comet assay

PubMed Central

Gülsoy, Nagihan; Yavas, Cüneyd; Mutlu, Özal

2015-01-01

The present study is conducted to determine the potential mechanisms of Boron compounds, boric acid (BA) and borax (BX), on genotoxicity of zebrafish Danio rerio for 24, 48, 72 and 96-hours acute exposure (level:1, 4, 16, 64 mg/l BA and BX) in semi-static bioassay experiment. For that purpose, peripheral erythrocytes were drawn from caudal vein and Comet assay was applied to assess genotoxicity. Acute (96 hours) exposure and high concentrations of boric acid and borax increases % tail DNA and Olive tail moment. Genotoxicity was found for BA as concentration-dependent and BX as concentration and time dependent manner. In general, significant effects (P < 0,05) on both concentrations and exposure times were observed in experimental groups. DNA damage was highest at 96 h and 24 h for all BX and BA concentrations, respectively in peripheral blood of D. rerio. For the first time, our study demonstrates the effect of waterborne BA and BX exposure on genotoxicity at the molecular level, which may contribute to understanding the mechanism of boric acid and borax-induced genotoxicity in fish. PMID:26862320

Genotoxic effects of boric acid and borax in zebrafish, Danio rerio using alkaline comet assay.

PubMed

Gülsoy, Nagihan; Yavas, Cüneyd; Mutlu, Özal

2015-01-01

The present study is conducted to determine the potential mechanisms of Boron compounds, boric acid (BA) and borax (BX), on genotoxicity of zebrafish Danio rerio for 24, 48, 72 and 96-hours acute exposure (level:1, 4, 16, 64 mg/l BA and BX) in semi-static bioassay experiment. For that purpose, peripheral erythrocytes were drawn from caudal vein and Comet assay was applied to assess genotoxicity. Acute (96 hours) exposure and high concentrations of boric acid and borax increases % tail DNA and Olive tail moment. Genotoxicity was found for BA as concentration-dependent and BX as concentration and time dependent manner. In general, significant effects (P < 0,05) on both concentrations and exposure times were observed in experimental groups. DNA damage was highest at 96 h and 24 h for all BX and BA concentrations, respectively in peripheral blood of D. rerio. For the first time, our study demonstrates the effect of waterborne BA and BX exposure on genotoxicity at the molecular level, which may contribute to understanding the mechanism of boric acid and borax-induced genotoxicity in fish.

Intestinal bacteria modify lymphoma incidence and latency by affecting systemic inflammatory state, oxidative stress, and leucocyte genotoxicity

PubMed Central

Yamamoto, Mitsuko L.; Maier, Irene; Dang, Angeline Tilly; Berry, David; Liu, Jared; Ruegger, Paul M.; Yang, Jiue-in; Soto, Phillip A.; Presley, Laura L.; Reliene, Ramune; Westbrook, Aya M.; Wei, Bo; Loy, Alexander; Chang, Christopher; Braun, Jonathan; Borneman, James; Schiestl, Robert H.

2013-01-01

Ataxia-telangiectasia (A-T) is a genetic disorder associated with high incidence of B cell lymphoma. Using an A-T mouse model, we compared lymphoma incidence in several isogenic mouse colonies harboring different bacterial communities, finding that intestinal microbiota are a major contributor to disease penetrance and latency, lifespan, molecular oxidative stress and systemic leucocyte genotoxicity. High throughput sequence analysis of rRNA genes identified mucosa-associated bacterial phylotypes that were colony-specific. Lactobacillus johnsonii, which was deficient in the more cancer-prone mouse colony, was causally tested for its capacity to confer reduced genotoxicity when restored by short-term oral transfer. This intervention decreased systemic genotoxicity, a response associated with reduced basal leucocytes and the cytokine-mediated inflammatory state, and mechanistically linked to the host cell biology of systemic genotoxicity. Our results suggest that intestinal microbiota are a potentially modifiable trait for translational intervention in individuals at risk for B cell lymphoma, or for other diseases that are driven by genotoxicity or the molecular response to oxidative stress. PMID:23860718

Genotoxic evaluation of an industrial effluent from an oil refinery using plant and animal bioassays.

PubMed

Rodrigues, Fernando Postalli; Angeli, José Pedro Friedmann; Mantovani, Mário Sérgio; Guedes, Carmen Luisa Barbosa; Jordão, Berenice Quinzani

2010-01-01

Polycyclic aromatic hydrocarbons (PAHs) are genotoxic chemicals commonly found in effluents from oil refineries. Bioassays using plants and cells cultures can be employed for assessing environmental safety and potential genotoxicity. In this study, the genotoxic potential of an oil refinery effluent was analyzed by means of micronucleus (MN) testing of Alium cepa, which revealed no effect after 24 h of treatment. On the other hand, primary lesions in the DNA of rat (Rattus norvegicus) hepatoma cells (HTC) were observed through comet assaying after only 2 h of exposure. On considering the capacity to detect DNA damage of a different nature and of these cells to metabolize xenobiotics, we suggest the association of the two bioassays with these cell types, plant (Allium cepa) and mammal (HTC) cells, for more accurately assessing genotoxicity in environmental samples.

Genotoxicity Biomonitoring Along a Coastal Zone Under Influence of Offshore Petroleum Exploration (Southeastern Brazil).

PubMed

Gutiérrez, Juan Manuel; da Conceição, Moisés Basilio; Molisani, Mauricio Mussi; Weber, Laura Isabel

2018-03-01

Offshore oil exploration creates threats to coastal ecosystems, including increasing urbanization and associated effluent releases. Genotoxicity biomarkers in mussels were determined across a gradient of coastal zone influences of offshore petroleum exploration in southeastern Brazil. Coastal ecosystems such as estuaries, beaches and islands were seasonally monitored for genotoxicity evaluation using the brown mussel Perna perna. The greatest DNA damage (5.2% ± 1.9% tail DNA and 1.5‰  ± 0.8‰ MN) were observed in urban estuaries, while Santana Archipelago showed levels of genotoxicity near zero and is considered a reference site. Mussels from urban and pristine beaches showed intermediate damage levels, but were also influenced by urbanization. Thus, mussel genotoxicity biomarkers greatly indicated the proposed oil exploration and urbanization scenarios that consequently are genetically affecting coastal organisms.

The use of ex vivo human skin tissue for genotoxicity testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reus, Astrid A.; Usta, Mustafa; Krul, Cyrille A.M., E-mail: cyrille.krul@tno.nl

2012-06-01

As a result of the chemical legislation concerning the registration, evaluation, authorization and restriction of chemicals (REACH), and the Seventh Amendment to the Cosmetics Directive, which prohibits animal testing in Europe for cosmetics, alternative methods for safety evaluation of chemicals are urgently needed. Current in vitro genotoxicity assays are not sufficiently predictive for the in vivo situation, resulting in an unacceptably high number of misleading positives. For many chemicals and ingredients of personal care products the skin is the first site of contact, but there are no in vitro genotoxicity assays available in the skin for additional evaluation of positivemore » or equivocal responses observed in regulatory in vitro genotoxicity assays. In the present study ex vivo human skin tissue obtained from surgery was used for genotoxicity evaluation of chemicals by using the comet assay. Fresh ex vivo human skin tissue was cultured in an air–liquid interface and topically exposed to 20 chemicals, including true positive, misleading positive and true negative genotoxins. Based on the results obtained in the present study, the sensitivity, specificity and accuracy of the ex vivo skin comet assay to predict in vivo genotoxicity were 89%, 90% and 89%, respectively. Donor and experimental variability were mainly reflected in the magnitude of the response and not the difference between the presence and absence of a genotoxic response. The present study indicates that human skin obtained from surgery is a promising and robust model for safety evaluation of chemicals that are in direct contact with the skin. -- Highlights: ► We use human skin obtained from surgery for genotoxicity evaluation of chemicals. ► We use the comet assay as parameter for genotoxicity in ex vivo human skin. ► Sensitivity, specificity and accuracy to predict in vivo genotoxins are determined. ► Sensitivity, specificity and accuracy are 89%, 90% and 90%, respectively. ► The method is suitable for evaluation of chemicals that are in contact with skin.« less

Comparison of in vivo genotoxic and carcinogenic potency to augment mode of action analysis: Case study with hexavalent chromium.

PubMed

Thompson, Chad M; Bichteler, Anne; Rager, Julia E; Suh, Mina; Proctor, Deborah M; Haws, Laurie C; Harris, Mark A

2016-04-01

Recent analyses-highlighted by the International Workshops on Genotoxicity Testing Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment-have identified a correlation between (log) estimates of a carcinogen's in vivo genotoxic potency and in vivo carcinogenic potency in typical laboratory animal models, even when the underlying data have not been matched for tissue, species, or strain. Such a correlation could have important implications for risk assessment, including informing the mode of action (MOA) of specific carcinogens. When in vivo genotoxic potency is weak relative to carcinogenic potency, MOAs other than genotoxicity (e.g., endocrine disruption or regenerative hyperplasia) may be operational. Herein, we review recent in vivo genotoxicity and carcinogenicity data for hexavalent chromium (Cr(VI)), following oral ingestion, in relevant tissues and species in the context of the aforementioned correlation. Potency estimates were generated using benchmark doses, or no-observable-adverse-effect-levels when data were not amenable to dose-response modeling. While the ratio between log values for carcinogenic and genotoxic potency was ≥1 for many compounds, the ratios for several Cr(VI) datasets (including in target tissue) were less than unity. In fact, the ratios for Cr(VI) clustered closely with ratios for chloroform and diethanolamine, two chemicals posited to have non-genotoxic MOAs. These findings suggest that genotoxicity may not play a major role in the cancers observed in rodents following exposure to high concentrations of Cr(VI) in drinking water-a finding consistent with recent MOA and adverse outcome pathway (AOP) analyses concerning Cr(VI). This semi-quantitative analysis, therefore, may be useful to augment traditional MOA and AOP analyses. More case examples will be needed to further explore the general applicability and validity of this approach for human health risk assessment. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Herbivore-induced Blueberry Volatiles and Intra-plant Signaling

PubMed Central

Rodriguez-Saona, Cesar R.

2011-01-01

Herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack1,2. These HIPVs are mainly regulated by the defensive plant hormone jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA)3,4,5. Over the past 3 decades researchers have documented that HIPVs can repel or attract herbivores, attract the natural enemies of herbivores, and in some cases they can induce or prime plant defenses prior to herbivore attack. In a recent paper6, I reported that feeding by gypsy moth caterpillars, exogenous MeJA application, and mechanical damage induce the emissions of volatiles from blueberry plants, albeit differently. In addition, blueberry branches respond to HIPVs emitted from neighboring branches of the same plant by increasing the levels of JA and resistance to herbivores (i.e., direct plant defenses), and by priming volatile emissions (i.e., indirect plant defenses). Similar findings have been reported recently for sagebrush7, poplar8, and lima beans9.. Here, I describe a push-pull method for collecting blueberry volatiles induced by herbivore (gypsy moth) feeding, exogenous MeJA application, and mechanical damage. The volatile collection unit consists of a 4 L volatile collection chamber, a 2-piece guillotine, an air delivery system that purifies incoming air, and a vacuum system connected to a trap filled with Super-Q adsorbent to collect volatiles5,6,10. Volatiles collected in Super-Q traps are eluted with dichloromethane and then separated and quantified using Gas Chromatography (GC). This volatile collection method was used n my study6 to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants. These methods are described here. Briefly, undamaged blueberry branches are exposed to HIPVs from neighboring branches within the same plant. Using the same techniques described above, volatiles emitted from branches after exposure to HIPVs are collected and analyzed. PMID:22214939

Formation and Repair of Tobacco Carcinogen-Derived Bulky DNA Adducts

DOE PAGES

Hang, Bo

2010-01-01

DNA adducts play a central role in chemical carcinogenesis. The analysis of formation and repair of smoking-related DNA adducts remains particularly challenging as both smokers and nonsmokers exposed to smoke are repetitively under attack from complex mixtures of carcinogens such as polycyclic aromatic hydrocarbons and N -nitrosamines. The bulky DNA adducts, which usually have complex structure, are particularly important because of their biological relevance. Several known cellular DNA repair pathways have been known to operate in human cells on specific types of bulky DNA adducts, for example, nucleotide excision repair, base excision repair, and direct reversal involving O 6 -alkylguaninemore » DNA alkyltransferase or AlkB homologs. Understanding the mechanisms of adduct formation and repair processes is critical for the assessment of cancer risk resulting from exposure to cigarette smoke, and ultimately for developing strategies of cancer prevention. This paper highlights the recent progress made in the areas concerning formation and repair of bulky DNA adducts in the context of tobacco carcinogen-associated genotoxic and carcinogenic effects.« less

Diet-related DNA adduct formation in relation to carcinogenesis.

PubMed

Hemeryck, Lieselot Y; Vanhaecke, Lynn

2016-08-01

The human diet contributes significantly to the initiation and promotion of carcinogenesis. It has become clear that the human diet contains several groups of natural foodborne chemicals that are at least in part responsible for the genotoxic, mutagenic, and carcinogenic potential of certain foodstuffs. Electrophilic chemicals are prone to attack nucleophilic sites in DNA, resulting in the formation of altered nucleobases, also known as DNA adducts. Since DNA adduct formation is believed to signal the onset of chemically induced carcinogenesis, the DNA adduct-inducing potential of certain foodstuffs has been investigated to gain more insight into diet-related pathways of carcinogenesis. Many studies have investigated diet-related DNA adduct formation. This review summarizes work on known or suspected dietary carcinogens and the role of DNA adduct formation in hypothesized carcinogenesis pathways. © The Author(s) 2016. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

EFFECT OF EXPOSURE PROTOCOL AND HEAT SHOCK PROTEIN EXPRESSION ON ARSENITE INDUCED GENOTOXICITY IN MCF-7 BREAST CANCER CELLS

EPA Science Inventory

Effect of exposure protocol and heat shock protein expression on arsenite induced genotoxicity in MCF-7 breast cancer cells

The genotoxic effects of arsenic (As) are well accepted, yet its mechanism of action is not clearly defined. Heat-shock proteins (HSPs) protect...

AN EVALUATION OF THE RELATIVE GENOTOXICITY OF ARSENITE, ARSENATE, AND FOUR METHYLATED METABOLITES IN VITRO USING THE ALKALINE SINGLE CELL GEL ASSAY

EPA Science Inventory

An Evaluation of the Relative Genotoxicity of Arsenite, Arsenate, and Four Methylated
Metabolites In Vitro Using the Alkaline Single Cell Gel Assay (ASCG).

Arsenic ( As) is a genotoxic and carcinogenic metal found in many drinking water systems throughout the world. ...

Silver nanoparticles: correlating nanoparticle size and cellular uptake with genotoxicity

PubMed Central

Butler, Kimberly S.; Peeler, David J.; Casey, Brendan J.; Dair, Benita J.; Elespuru, Rosalie K.

2015-01-01

The focus of this research was to develop a better understanding of the pertinent physico-chemical properties of silver nanoparticles (AgNPs) that affect genotoxicity, specifically how cellular uptake influences a genotoxic cell response. The genotoxicity of AgNPs was assessed for three potential mechanisms: mutagenicity, clastogenicity and DNA strand-break-based DNA damage. Mutagenicity (reverse mutation assay) was assessed in five bacterial strains of Salmonella typhimurium and Echerichia coli, including TA102 that is sensitive to oxidative DNA damage. AgNPs of all sizes tested (10, 20, 50 and 100nm), along with silver nitrate (AgNO3), were negative for mutagenicity in bacteria. No AgNPs could be identified within the bacteria cells using transmission electron microscopy (TEM), indicating these bacteria lack the ability to actively uptake AgNPs 10nm or larger. Clastogenicity (flow cytometry-based micronucleus assay) and intermediate DNA damage (DNA strand breaks as measured in the Comet assay) were assessed in two mammalian white blood cell lines: Jurkat Clone E6-1 and THP-1. It was observed that micronucleus and Comet assay end points were inversely correlated with AgNP size, with smaller NPs inducing a more genotoxic response. TEM results indicated that AgNPs were confined within intracellular vesicles of mammalian cells and did not penetrate the nucleus. The genotoxicity test results and the effect of AgNO3 controls suggest that silver ions may be the primary, and perhaps only, cause of genotoxicity. Furthermore, since AgNO3 was not mutagenic in the gram-negative bacterial Ames strains tested, the lack of bacterial uptake of the AgNPs may not be the major reason for the lack of genotoxicity observed. PMID:25964273

Detection of genotoxic and non-genotoxic carcinogens in Xpc(-/-)p53(+/-) mice.

PubMed

Melis, Joost P M; Speksnijder, Ewoud N; Kuiper, Raoul V; Salvatori, Daniela C F; Schaap, Mirjam M; Maas, Saskia; Robinson, Joke; Verhoef, Aart; van Benthem, Jan; Luijten, Mirjam; van Steeg, Harry

2013-01-15

An accurate assessment of the carcinogenic potential of chemicals and pharmaceutical drugs is essential to protect humans and the environment. Therefore, substances are extensively tested before they are marketed to the public. Currently, the rodent two-year bioassay is still routinely used to assess the carcinogenic potential of substances. However, over time it has become clear that this assay yields false positive results and also has several economic and ethical drawbacks including the use of large numbers of animals, the long duration, and the high cost. The need for a suitable alternative assay is therefore high. Previously, we have proposed the Xpa*p53 mouse model as a very suitable alternative to the two-year bioassay. We now show that the Xpc*p53 mouse model preserves all the beneficial traits of the Xpa*p53 model for sub-chronic carcinogen identification and can identify both genotoxic and non-genotoxic carcinogens. Moreover, Xpc*p53 mice appear to be more responsive than Xpa*p53 mice towards several genotoxic and non-genotoxic carcinogens. Furthermore, Xpc*p53 mice are far less sensitive than Xpa*p53 mice for the toxic activity of DNA damaging agents and as such clearly respond in a similar way as wild type mice do. These advantageous traits of the Xpc*p53 model make it a better alternative for in vivo carcinogen testing than Xpa*p53. This pilot study suggests that Xpc*p53 mice are suited for routine sub-chronic testing of both genotoxic and non-genotoxic carcinogens and as such represent a suitable alternative to possibly replace the murine life time cancer bioassay. Copyright © 2012 Elsevier Inc. All rights reserved.

Size- and coating-dependent cytotoxicity and genotoxicity of silver nanoparticles evaluated using in vitro standard assays.

PubMed

Guo, Xiaoqing; Li, Yan; Yan, Jian; Ingle, Taylor; Jones, Margie Yvonne; Mei, Nan; Boudreau, Mary D; Cunningham, Candice K; Abbas, Mazhar; Paredes, Angel M; Zhou, Tong; Moore, Martha M; Howard, Paul C; Chen, Tao

2016-11-01

The physicochemical characteristics of silver nanoparticles (AgNPs) may greatly alter their toxicological potential. To explore the effects of size and coating on the cytotoxicity and genotoxicity of AgNPs, six different types of AgNPs, having three different sizes and two different coatings, were investigated using the Ames test, mouse lymphoma assay (MLA) and in vitro micronucleus assay. The genotoxicities of silver acetate and silver nitrate were evaluated to compare the genotoxicity of nanosilver to that of ionic silver. The Ames test produced inconclusive results for all types of the silver materials due to the high toxicity of silver to the test bacteria and the lack of entry of the nanoparticles into the cells. Treatment of L5718Y cells with AgNPs and ionic silver resulted in concentration-dependent cytotoxicity, mutagenicity in the Tk gene and the induction of micronuclei from exposure to nearly every type of the silver materials. Treatment of TK6 cells with these silver materials also resulted in concentration-dependent cytotoxicity and significantly increased micronucleus frequency. With both the MLA and micronucleus assays, the smaller the AgNPs, the greater the cytotoxicity and genotoxicity. The coatings had less effect on the relative genotoxicity of AgNPs than the particle size. Loss of heterozygosity analysis of the induced Tk mutants indicated that the types of mutations induced by AgNPs were different from those of ionic silver. These results suggest that AgNPs induce cytotoxicity and genotoxicity in a size- and coating-dependent manner. Furthermore, while the MLA and in vitro micronucleus assay (in both types of cells) are useful to quantitatively measure the genotoxic potencies of AgNPs, the Ames test cannot.

Mechanisms related to the genotoxicity of particles in the subway and from other sources.

PubMed

Karlsson, Hanna L; Holgersson, Asa; Möller, Lennart

2008-03-01

Negative health effects of airborne particles have clearly been shown in epidemiological studies. People get exposed to particles from various sources such as the combustion of, for example, diesel and wood and also from particles arising from tire-road wear. Another source of importance for certain populations is exposure to particles in subway systems. We recently reported that these particles were more genotoxic when compared to that of several other particle types. The aim of this study was to further investigate and compare the toxicity of subway particles and particles from other sources as well as investigate some mechanisms behind the genotoxicity of subway particles. This was done by comparing the ability of subway particles and particles from a street, pure tire-road wear particles, and particles from wood and diesel combustion to cause mitochondrial depolarization and to form intracellular reactive oxygen species (ROS). Furthermore, the genotoxicity and ability to cause oxidative stress was compared to magnetite particles since this is a main component in subway particles. It was concluded that the subway particles and also street particles and particles from wood and diesel combustion caused mitochondrial depolarization. The ability to damage the mitochondria is thus not the only explanation for the high genotoxicity of subway particles. Subway particles also formed intracellular ROS. This effect may be part of the explanation as to why subway particles show such high genotoxicity when compared to that of other particles. Genotoxicity can, however, not be explained by the main component, magnetite, by water-soluble metals, or by intracellular mobilized iron. The genotoxicity is most likely caused by highly reactive surfaces giving rise to oxidative stress.

Genotoxic effects of occupational exposure to benzene in gasoline station workers

PubMed Central

SALEM, Eman; EL-GARAWANI, Islam; ALLAM, Heba; EL-AAL, Bahiga Abd; HEGAZY, Mofrih

2017-01-01

Benzene, a hazardous component of gasoline, is a genotoxic class I human carcinogen. This study evaluated the genotoxic effects of occupational exposure to benzene in gasoline stations. Genotoxicity of exposure to benzene was assessed in peripheral blood leucocytes of 62 gasoline station workers and compared with an equal numbers of matched controls using total genomic DNA fragmentation, micronucleus test and cell viability test. An ambient air samples were collected and analyzed for Monitoring of benzene, toluene, ethyl benzene and xylene (BTEX) in work environment and control areas. DNA fragmentation, micronucleus and dead cells percent were significantly higher in exposed workers than controls. Level of benzene, Toluene, Ethyl benzene and xylene in the work environment were higher than the control areas and the permissible limits. Gasoline station workers occupationally exposed to benzene are susceptible to genotoxic effects indicated by increased DNA fragmentation, higher frequency of micronucleus and decreased leukocytes viability. PMID:29070767

Toxicological and analytical investigations of noni (Morinda citrifolia) fruit juice.

PubMed

Westendorf, Johannes; Effenberger, Katharina; Iznaguen, Hassan; Basar, Simla

2007-01-24

Morinda citrifolia (noni) is known to contain genotoxic anthraquinones in the roots. Because of the widespread use of noni juice, the possible genotoxic risk was examined through a battery of short-term tests. Noni juice was also chemically analyzed for the possible presence of anthraquinones. Noni juice extract in the Salmonella microsome assay showed a slight mutagenic effect in strain TA1537, due to the presence of flavonoids. No mutagenicity was observed in the mammalian mutagenicity test with V79 Chinese hamster fibroblasts. Rats treated with a noni juice concentrate did not show DNA repair synthesis (UDS) in primary rat hepatocytes, nor could DNA adducts or DNA strand breaks be observed. HPLC analysis of noni juice for anthraquinones was negative, with a sensitivity of <1 ppm. In summary, chemical analysis and genotoxicity tests reveal that noni juice does not have a genotoxic potential and that genotoxic anthraquinones do not exist in noni juice.

Genotoxic effects of occupational exposure to benzene in gasoline station workers.

PubMed

Salem, Eman; El-Garawani, Islam; Allam, Heba; El-Aal, Bahiga Abd; Hegazy, Mofrih

2018-04-07

Benzene, a hazardous component of gasoline, is a genotoxic class I human carcinogen. This study evaluated the genotoxic effects of occupational exposure to benzene in gasoline stations. Genotoxicity of exposure to benzene was assessed in peripheral blood leucocytes of 62 gasoline station workers and compared with an equal numbers of matched controls using total genomic DNA fragmentation, micronucleus test and cell viability test. An ambient air samples were collected and analyzed for Monitoring of benzene, toluene, ethyl benzene and xylene (BTEX) in work environment and control areas. DNA fragmentation, micronucleus and dead cells percent were significantly higher in exposed workers than controls. Level of benzene, Toluene, Ethyl benzene and xylene in the work environment were higher than the control areas and the permissible limits. Gasoline station workers occupationally exposed to benzene are susceptible to genotoxic effects indicated by increased DNA fragmentation, higher frequency of micronucleus and decreased leukocytes viability.

Physico-chemical and genotoxicity analysis of Guaribas river water in the Northeast Brazil.

PubMed

de Castro E Sousa, João Marcelo; Peron, Ana Paula; da Silva, Felipe Cavalcanti Carneiro; de Siqueira Dantas, Ellifran Bezerra; de Macedo Vieira Lima, Ataíde; de Oliveira, Victor Alves; Matos, Leomá Albuquerque; Paz, Márcia Fernanda Correia Jardim; de Alencar, Marcus Vinicius Oliveira Barros; Islam, Muhammad Torequl; de Carvalho Melo-Cavalcante, Ana Amélia; Bonecker, Cláudia Costa; Júlio, Horácio Ferreira

2017-06-01

River pollution in Brazil is significant. This study aimed to evaluate the physico-chemical and genotoxic profiles of the Guaribas river water, located in Northeast Brazil (State of Piauí, Brazil). The study conducted during the dry and wet seasons to understand the frequency of pollution throughout the year. Genotoxicity analysis was done with the blood of Oreochromis niloticus by using the comet assay. Water samples were collected from upstream, within and downstream the city Picos. The results suggest a significant (p < 0.05) genotoxic effect of the Guaribas river water when compared to the control group. In comparison to the control group, in the river water we found a significant increase in metals such as - Fe, Zn, Cr, Cu and Al. In conclusion, Guaribas river carries polluted water, especially a large quantity of toxic metals, which may impart the genotoxic effect. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmental genotoxicity and risk assessment in the Gulf of Riga (Baltic Sea) using fish, bivalves, and crustaceans.

PubMed

Butrimavičienė, Laura; Baršienė, Janina; Greiciūnaitė, Janina; Stankevičiūtė, Milda; Valskienė, Roberta

2018-06-21

Environmental genotoxicity in the Gulf of Riga was assessed using different bioindicators (fish, clams, and isopods) collected from 14 study stations. Comparison of genotoxicity responses (micronuclei (MN) and nuclear buds (NB)) in blood erythrocytes of herring (Clupea harengus), eelpout (Zoarces viviparous), and flounder (Platichthys flesus) revealed the species- and site-specific differences. For the first time, the analysis of genotoxicity was carried out in gill cells of isopods Saduria entomon. The highest inductions of MN and NB in gill cells of investigated S. entomon and clams (Macoma balthica) were evaluated in specimens from station 111A (offshore zone). In fish, the highest incidences of MN were measured in eelpout and in herring collected in the southern part of Gulf of Riga (station GOR3/41S). Moreover, in the southern coastal area, the assessment of genotoxicity risk (according to micronuclei levels) indicated exceptionally high risk for flounder, eelpout, and clams.

By-product mutualism with evolving common enemies.

PubMed

De Jaegher, Kris

2017-05-07

The common-enemy hypothesis of by-product mutualism states that organisms cooperate when it is in their individual interests to do so, with benefits for other organisms arising as a by-product; in particular, such cooperation is hypothesized to arise when organisms face the common enemy of a sufficiently adverse environment. In an evolutionary game where two defenders can cooperate to defend a common resource, this paper analyzes the common-enemy hypothesis when adversity is endogenous, in that an attacker sets the number of attacks. As a benchmark, we first consider exogenous adversity, where adversity is not subject to evolution. In this case, the common-enemy hypothesis is predicted when the degree of complementarity between defenders' defensive efforts is sufficiently low. When the degree of complementarity is high, the hypothesis is predicted only when cooperation costs are high; when cooperation costs are instead low, a competing hypothesis is predicted, where adversity discourages cooperation. Second, we consider the case of endogenous adversity. In this case, we continue to predict the competing hypothesis for a high degree of complementarity and low cooperation costs. The common-enemy hypothesis, however, only continues to be predicted for the lowest degrees of complementarity. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Theoretical Study of 8-Chloro-9-Hydroxy-Aflatoxin B1, the Conversion Product of Aflatoxin B1 by Neutral Electrolyzed Water

PubMed Central

Escobedo-González, René; Méndez-Albores, Abraham; Villarreal-Barajas, Tania; Aceves-Hernández, Juan Manuel; Miranda-Ruvalcaba, René; Nicolás-Vázquez, Inés

2016-01-01

Theoretical studies of 8-chloro-9-hydroxy-aflatoxin B1 (2) were carried out by Density Functional Theory (DFT). This molecule is the reaction product of the treatment of aflatoxin B1 (1) with hypochlorous acid, from neutral electrolyzed water. Determination of the structural, electronic and spectroscopic properties of the reaction product allowed its theoretical characterization. In order to elucidate the formation process of 2, two reaction pathways were evaluated—the first one considering only ionic species (Cl+ and OH−) and the second one taking into account the entire hypochlorous acid molecule (HOCl). Both pathways were studied theoretically in gas and solution phases. In the first suggested pathway, the reaction involves the addition of chlorenium ion to 1 forming a non-classic carbocation assisted by anchimeric effect of the nearest aromatic system, and then a nucleophilic attack to the intermediate by the hydroxide ion. In the second studied pathway, as a first step, the attack of the double bond from the furanic moiety of 1 to the hypochlorous acid is considered, accomplishing the same non-classical carbocation, and again in the second step, a nucleophilic attack by the hydroxide ion. In order to validate both reaction pathways, the atomic charges, the highest occupied molecular orbital and the lowest unoccupied molecular orbital were obtained for both substrate and product. The corresponding data imply that the C9 atom is the more suitable site of the substrate to interact with the hydroxide ion. It was demonstrated by theoretical calculations that a vicinal and anti chlorohydrin is produced in the terminal furan ring. Data of the studied compound indicate an important reduction in the cytotoxic and genotoxic potential of the target molecule, as demonstrated previously by our research group using different in vitro assays. PMID:27455324

Acute toxicity and genotoxic activity of avocado seed extract (Persea americana Mill., c.v. Hass).

PubMed

Padilla-Camberos, Eduardo; Martínez-Velázquez, Moisés; Flores-Fernández, José Miguel; Villanueva-Rodríguez, Socorro

2013-01-01

The use of vegetal extracts requires toxicological and genotoxic evaluations to establish and verify safety before being added to human cosmetic, pharmaceutical medicine, or alimentary products. Persea americana seeds have been used in traditional medicine as treatment for several diseases. In this work, the ethanolic seed extract of Persea americana was evaluated with respect to its genotoxic potential through micronucleus assay in rodents. The frequency of micronuclei in groups of animals treated with avocado seed extract showed no differences compared to the negative control (vehicle); therefore, it is considered that the avocado seed extract showed no genotoxic activity in the micronucleus test.

Acute Toxicity and Genotoxic Activity of Avocado Seed Extract (Persea americana Mill., c.v. Hass)

PubMed Central

Padilla-Camberos, Eduardo; Martínez-Velázquez, Moisés; Flores-Fernández, José Miguel; Villanueva-Rodríguez, Socorro

2013-01-01

The use of vegetal extracts requires toxicological and genotoxic evaluations to establish and verify safety before being added to human cosmetic, pharmaceutical medicine, or alimentary products. Persea americana seeds have been used in traditional medicine as treatment for several diseases. In this work, the ethanolic seed extract of Persea americana was evaluated with respect to its genotoxic potential through micronucleus assay in rodents. The frequency of micronuclei in groups of animals treated with avocado seed extract showed no differences compared to the negative control (vehicle); therefore, it is considered that the avocado seed extract showed no genotoxic activity in the micronucleus test. PMID:24298206

Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials

PubMed Central

Ibañez-Cabellos, José Santiago; de Cutanda, Sergio Bañuls-Sánchez; Berenguer-Pascual, Ester; Beltrán-García, Jesús; García-López, Eva; Pallardó, Federico V.; García-Giménez, José Luis; Pallarés-Sabater, Antonio; Zarzosa-López, Ignacio; Monterde, Manuel

2017-01-01

Human dental pulp stem cells (HDPSCs) are of special relevance in future regenerative dental therapies. Characterizing cytotoxicity and genotoxicity produced by endodontic materials is required to evaluate the potential for regeneration of injured tissues in future strategies combining regenerative and root canal therapies. This study explores the cytotoxicity and genotoxicity mediated by oxidative stress of three endodontic materials that are widely used on HDPSCs: a mineral trioxide aggregate (MTA-Angelus white), an epoxy resin sealant (AH-Plus cement), and an MTA-based cement sealer (MTA-Fillapex). Cell viability and cell death rate were assessed by flow cytometry. Oxidative stress was measured by OxyBlot. Levels of antioxidant enzymes were evaluated by Western blot. Genotoxicity was studied by quantifying the expression levels of DNA damage sensors such as ATM and RAD53 genes and DNA damage repair sensors such as RAD51 and PARP-1. Results indicate that AH-Plus increased apoptosis, oxidative stress, and genotoxicity markers in HDPSCs. MTA-Fillapex was the most cytotoxic oxidative stress inductor and genotoxic material for HDPSCs at longer times in preincubated cell culture medium, and MTA-Angelus was less cytotoxic and genotoxic than AH-Plus and MTA-Fillapex at all times assayed. PMID:28751918

Molecular Mechanisms of Zinc Oxide Nanoparticle-Induced Genotoxicity Short Running Title: Genotoxicity of ZnO NPs

PubMed Central

Scherzad, Agmal; Meyer, Till; Kleinsasser, Norbert

2017-01-01

Background: Zinc oxide nanoparticles (ZnO NPs) are among the most frequently applied nanomaterials in consumer products. Evidence exists regarding the cytotoxic effects of ZnO NPs in mammalian cells; however, knowledge about the potential genotoxicity of ZnO NPs is rare, and results presented in the current literature are inconsistent. Objectives: The aim of this review is to summarize the existing data regarding the DNA damage that ZnO NPs induce, and focus on the possible molecular mechanisms underlying genotoxic events. Methods: Electronic literature databases were systematically searched for studies that report on the genotoxicity of ZnO NPs. Results: Several methods and different endpoints demonstrate the genotoxic potential of ZnO NPs. Most publications describe in vitro assessments of the oxidative DNA damage triggered by dissoluted Zn2+ ions. Most genotoxicological investigations of ZnO NPs address acute exposure situations. Conclusion: Existing evidence indicates that ZnO NPs possibly have the potential to damage DNA. However, there is a lack of long-term exposure experiments that clarify the intracellular bioaccumulation of ZnO NPs and the possible mechanisms of DNA repair and cell survival. PMID:29240707

Comparison of the in vivo and in vitro genotoxicity of glyphosate isopropylamine salt in three different organisms

PubMed Central

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Ramírez, Carlos Valdez; Gallardo, David Gómez; Sánchez, Rafael León; Aguirre, Alejandro Canales; Velasco, Alfredo Feria

2014-01-01

There is considerable controversy with regard to the genotoxicity of glyphosate, with some reports stating that this compound is non-toxic for fish, birds and mammals. In this work, we used the comet assay to examine the genotoxicity of glyphosate isopropylamine (0.7, 7, 70 and 700 μM) in human lymphocytes, erythrocytes of Oreochromis niloticus and staminal nuclei of Tradescantia (4430) in vitro and in vivo. Cells, nuclei and fish that had and had not been exposed to 5 mM N-nitrosodiethylamine (NDEA) were used as positive and negative controls, respectively. Significant (p < 0.01) genetic damage was observed in vivo and in vitro in all cell types and organisms tested. Human lymphocytes and Tradescantia hairs showed lower genetic damage in vivo compared to in vitro, possibly because of efficient metabolization of the herbicide. In O. niloticus erythrocytes, significant (p < 0.001) genotoxicity was observed at ≥ 7 μM, whereas in vitro, glyphosphate was genotoxic in human lymphocytes and Tradescantia hairs at ≥ 0.7 μM. These results indicate that glyphosate is genotoxic in the cells and organisms studied at concentrations of 0.7–7 μM. PMID:24688297

Comparison of the in vivo and in vitro genotoxicity of glyphosate isopropylamine salt in three different organisms.

PubMed

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Ramírez, Carlos Valdez; Gallardo, David Gómez; Sánchez, Rafael León; Aguirre, Alejandro Canales; Velasco, Alfredo Feria

2014-03-01

There is considerable controversy with regard to the genotoxicity of glyphosate, with some reports stating that this compound is non-toxic for fish, birds and mammals. In this work, we used the comet assay to examine the genotoxicity of glyphosate isopropylamine (0.7, 7, 70 and 700 μM) in human lymphocytes, erythrocytes of Oreochromis niloticus and staminal nuclei of Tradescantia (4430) in vitro and in vivo. Cells, nuclei and fish that had and had not been exposed to 5 mM N-nitrosodiethylamine (NDEA) were used as positive and negative controls, respectively. Significant (p < 0.01) genetic damage was observed in vivo and in vitro in all cell types and organisms tested. Human lymphocytes and Tradescantia hairs showed lower genetic damage in vivo compared to in vitro, possibly because of efficient metabolization of the herbicide. In O. niloticus erythrocytes, significant (p < 0.001) genotoxicity was observed at ≥ 7 μM, whereas in vitro, glyphosphate was genotoxic in human lymphocytes and Tradescantia hairs at ≥ 0.7 μM. These results indicate that glyphosate is genotoxic in the cells and organisms studied at concentrations of 0.7-7 μM.

Ecotoxicological and Genotoxic Evaluation of Buenos Aires City (Argentina) Hospital Wastewater

PubMed Central

Juárez, Ángela Beatriz; Dragani, Valeria; Saenz, Magalí Elizabeth; Moretton, Juan

2014-01-01

Hospital wastewater (HWW) constitutes a potential risk to the ecosystems and human health due to the presence of toxic and genotoxic chemical compounds. In the present work we investigated toxicity and genotoxicity of wastewaters from the public hospital of Buenos Aires (Argentina). The effluent from the sewage treatment plant (STP) serving around 10 million inhabitants was also evaluated. The study was carried out between April and September 2012. Toxicity and genotoxicity assessment was performed using the green algae Pseudokirchneriella subcapitata and the Allium cepa test, respectively. Toxicity assay showed that 55% of the samples were toxic to the algae (%I of growth between 23.9 and 54.8). The A. cepa test showed that 40% of the samples were genotoxic. The analysis of chromosome aberrations (CA) and micronucleus (MN) showed no significant differences between days and significant differences between months. The sample from the STP was not genotoxic to A. cepa but toxic to the algae (%I = 41%), showing that sewage treatment was not totally effective. This study highlights the need for environmental control programs and the establishment of advanced and effective effluent treatment plants in the hospitals, which are merely dumping the wastewaters in the municipal sewerage system. PMID:25214834

Genotoxicity potential of a new natural formicide.

PubMed

Cotelle, Sylvie; Testolin, Renan C; Foltête, Anne-Sophie; Bossardi-Rissardi, Georgiana; Silveira, Rosilene A; Radetski, Claudemir M

2012-03-01

Assessment of environmental impacts from pesticide utilization should include genotoxicity studies, where the possible effects of mutagenic/genotoxic substances on individuals are assessed. In this study, the genotoxicity profile of the new formicide Macex® was evaluated with two genotoxicity tests, namely, the micronucleus test with mouse bone marrow and Vicia faba, and a mutagenicity test using the Ames Salmonella assay. The bacterial reverse mutation test (Salmonella typhimurium strains TA97, TA98, TA100, TA102, and TA1535), the Vicia root tip and mouse micronucleus tests were conducted according to published protocols. In the range of the formicide Macex® concentrations tested from 0.06 to 1.0 g L⁻¹ (or mgkg⁻¹ in the mouse test), no genotoxicity was observed in the prokaryotic or eukaryotic test organisms. However, at Macex® concentrations of 0.5 g L⁻¹ and above a significant decrease in the mitotic index (P ≤ 0.05) in the V. faba was observed. Micronucleus formation was likewise increased in the test organism at concentrations starting at 2.0 g L⁻¹. These data allow us to classify this natural formicide preparation as a product with no geno-environmental-impact when applied at recommended concentrations.

Endogenous T cell responses to antigens expressed in lung adenocarcinomas delay malignant tumor progression

PubMed Central

DuPage, Michel; Cheung, Ann; Mazumdar, Claire; Winslow, Monte M.; Bronson, Roderick; Schmidt, Leah M.; Crowley, Denise; Chen, Jianzhu; Jacks, Tyler

2010-01-01

SUMMARY Neoantigens derived from somatic mutations in tumors may provide a critical link between the adaptive immune system and cancer. Here we describe a system to introduce exogenous antigens into genetically engineered mouse lung cancers to mimic tumor neoantigens. We show that endogenous T cells respond to and infiltrate tumors, significantly delaying malignant progression. Despite continued antigen expression, T cell infiltration does not persist and tumors ultimately escape immune attack. Transplantation of cell lines derived from these lung tumors or prophylactic vaccination against the autochthonous tumors, however, results in rapid tumor eradication or selection of tumors that lose antigen expression. These results provide insight into the dynamic nature of the immune response to naturally arising tumors. PMID:21251614

Cytotoxicity and genotoxicity of polyethylenimine and nickel chloride in red sea bream ( Pagrosomus major) fin cell line RSBF

NASA Astrophysics Data System (ADS)

Guo, Hua-Rong; Zhang, Shi-Cui

2002-12-01

A continuous marine fish cell line RSBF (i. c. Red Sea Bream Fin) was utilized to screen the cytotoxicity and genotoxicity of polyethylenimine (PEI) and nickel chloride (NiCl2) in this study on the deleterious effects of aquatic genotoxins on fish. At the 0.01 to 1 μg/ml concentration tested, PEI had acute toxicity to the treated RSBF cells (IC50=1.12, 0.92, 0.88 and 0.64 μg/ml PEI for time 0 h, 24 h, 48 h and 72 h after treatment, respectively) and markedly inhibited their proliferation in a dose-dependent manner. At the 0.001 to 5 μmol/L concentration tested, NiCl2 posed no acute toxicity but significantly stimulated their growth (107% 214% of control). Random amplified polymorphic DNA (RAPD) technique was used to detect the genotoxic effects of PEI and NiCl2 by comparing the RAPD banding patterns of the control and treated cells. RAPD analysis indicated that at the concentrations tested, PEI was more genotoxic than NiCl2 to RSBF cells; that there was a slight dose-dependent response in the genotoxic effect of PEI but not NiCl2; and that RAPD technique might provide a sensitive, non-specific genotoxic endpoint. And the potent cytotoxicity and genotoxicity of PEI on fish cells showed that we should be cautious in utilizing it as gene, vector in fish gene transfer and human gene therapy.

Evaluation of protective effect of amifostine on dacarbazine induced genotoxicity.

PubMed

Etebari, M; Jafarian-Dehkordi, A; Lame, V

2015-01-01

Anticancer therapy with alkylating agents has been used for many years. Dacarbazine (DTIC) as an alkylating agent is used alone or in combination with other chemotherapy drugs. In order to inhibit the formation of secondary cancers resulting from chemotherapy with DTIC, preventional strategies is necessary. The present study was undertaken to evaluate the genoprotective effect of amifostine on the genotoxic effects of DTIC in cell culture condition. To determine the optimum genotoxic concentration of DTIC, HepG2 cells were incubated with various DTIC concentrations including 5, 10 and 20 μg/ml for 2 h and the genotoxic effects were evaluated by the comet assay. The result of this part of the study showed that incubation of HepG2 cells with DTIC at 5 μg/ml was sufficient to produce genotoxic effect. In order to determine the protective effects of amifostine on genotoxicity induced by DTIC, HepG2 cells were incubated with different concentrations of amifostine (2, 3 and 5 mg/ml) for 1 h which was followed by incubation with DTIC at 5 μg/ml for 2 h. One hour incubation of cells with different concentrations of amifostine before incubation with DITC indicated that at least 5 mg/ml concentration of amifostine can prevent genotoxic effects induced by DTIC on HepG2 cells under described condition. In conclusion amifostine could prevent DNA damage induced by DTIC on HepG2 cells.

Genotoxic capacity of Cd/Se semiconductor quantum dots with differing surface chemistries

PubMed Central

Manshian, Bella B.; Soenen, Stefaan J.; Brown, Andy; Hondow, Nicole; Wills, John; Jenkins, Gareth J. S.; Doak, Shareen H.

2016-01-01

Quantum dots (QD) have unique electronic and optical properties promoting biotechnological advances. However, our understanding of the toxicological structure–activity relationships remains limited. This study aimed to determine the biological impact of varying nanomaterial surface chemistry by assessing the interaction of QD with either a negative (carboxyl), neutral (hexadecylamine; HDA) or positive (amine) polymer coating with human lymphoblastoid TK6 cells. Following QD physico-chemical characterisation, cellular uptake was quantified by optical and electron microscopy. Cytotoxicity was evaluated and genotoxicity was characterised using the micronucleus assay (gross chromosomal damage) and the HPRT forward mutation assay (point mutagenicity). Cellular damage mechanisms were also explored, focusing on oxidative stress and mitochondrial damage. Cell uptake, cytotoxicity and genotoxicity were found to be dependent on QD surface chemistry. Carboxyl-QD demonstrated the smallest agglomerate size and greatest cellular uptake, which correlated with a dose dependent increase in cytotoxicity and genotoxicity. Amine-QD induced minimal cellular damage, while HDA-QD promoted substantial induction of cell death and genotoxicity. However, HDA-QD were not internalised by the cells and the damage they caused was most likely due to free cadmium release caused by QD dissolution. Oxidative stress and induced mitochondrial reactive oxygen species were only partially associated with cytotoxicity and genotoxicity induced by the QD, hence were not the only mechanisms of importance. Colloidal stability, nanoparticle (NP) surface chemistry, cellular uptake levels and the intrinsic characteristics of the NPs are therefore critical parameters impacting genotoxicity induced by QD. PMID:26275419

Evaluation of human embryonic stem cells and their differentiated fibroblastic progenies as cellular models for in vitro genotoxicity screening.

PubMed

Vinoth, Kumar Jayaseelan; Manikandan, Jayapal; Sethu, Swaminathan; Balakrishnan, Lakshmidevi; Heng, Alexis; Lu, Kai; Hande, Manoor Prakash; Cao, Tong

2014-08-20

This study evaluated human embryonic stem cells (hESC) and their differentiated fibroblastic progenies as cellular models for genotoxicity screening. The DNA damage response of hESCs and their differentiated fibroblastic progenies were compared to a fibroblastic cell line (HEPM, CRL1486) and primary cultures of peripheral blood lymphocytes (PBL), upon exposure to Mitomycin C, gamma irradiation and H2O2. It was demonstrated that hESC-derived fibroblastic progenies (H1F) displayed significantly higher chromosomal aberrations, micronuclei formation and double strand break (DSB) formation, as compared to undifferentiated hESC upon exposure to genotoxic stress. Nevertheless, H1F cell types displayed comparable sensitivities to genotoxic challenge as HEPM and PBL, both of which are representative of somatic cell types commonly used for genotoxicity screening. Subsequently, transcriptomic and pathways analysis identified differential expression of critical genes involved in cell death and DNA damage response upon exposure to gamma irradiation. The results thus demonstrate that hESC-derived fibroblastic progenies are as sensitive as commonly-used somatic cell types for genotoxicity screening. Moreover, hESCs have additional advantages, such as their genetic normality compared to immortalized cell lines, as well as their amenability to scale-up for producing large, standardized quantities of cells for genotoxicity screening on an industrial scale, something which can never be achieved with primary cell cultures. Copyright © 2014. Published by Elsevier B.V.

Impacts of fullerene C60 and virgin olive oil on cadmium-induced genotoxicity in rats.

PubMed

Aly, Fayza M; Kotb, Ahmed M; Haridy, Mohie A M; Hammad, Seddik

2018-07-15

Currently, cadmium is considered to be one of the major environmental pollutants. Environmentally, cadmium is released in various forms e.g. oxide, chloride and sulphide. The aim of the present study was to examine the genotoxic impact of fullerene nanoparticles C 60 (C 60 ) and virgin olive oil (VOO) on cadmium chloride (CdCl 2 )-induced genotoxicity in rats. To evaluate these effects on DNA damage and chromosomal frequency, 25 albino rats were randomly assigned to 5 groups (n=5 per group): Group 1 served as a control; Group 2 received a single intraperitoneal dose of CdCl 2 (3.5mg/kg); Group 3 animals were treated with C 60 (4mg/kg, orally) every other day for 20days; Group 4 received a single intraperitoneal dose of CdCl 2 (3.5mg/kg) and an oral dose of C 60 (4mg/kg); and Group 5 received a single intraperitoneal dose of CdCl 2 (3.5mg/kg) and oral doses of VOO every other day for 20 consecutive days. Genotoxic and anti-genotoxic effects of C 60 and VOO were evaluated in the liver, kidney and bone marrow using molecular and cytogenetic assays. As expected, CdCl 2 and C 60 administration was associated with band number alterations in both liver and kidney; however, C 60 pretreatment recovered to approximately basal number. Surprisingly, C 60 and VOO significantly attenuated the genotoxic effects caused by CdCl 2 in livers and kidneys. In bone marrow, in addition to a reduction in the chromosomal number, several chromosomal aberrations were caused by CdCl 2 . These chromosomal alterations were also reversed by C 60 and VOO. In conclusion, molecular and cytogenetic studies showed that C 60 and VOO exhibit anti-genotoxic agents against CdCl 2 -induced genotoxicity in rats. Further studies are needed to investigate the optimal conditions for potential biomedical applications of these anti-genotoxic agents. Copyright © 2018 Elsevier B.V. All rights reserved.

Further analysis of Ames-negative rodent carcinogens that are only genotoxic in mammalian cells in vitro at concentrations exceeding 1 mM, including retesting of compounds of concern.

PubMed

Kirkland, David; Fowler, Paul

2010-11-01

In the analysis by Parry et al. [Parry, J. M., Parry, E., Phrakonkham, P. and Corvi, R. (2010) Analysis of published data for top concentration considerations in mammalian cell genotoxicity testing. Mutagenesis, 25, 531-538], 24 rodent carcinogens that were negative in the Ames test were identified that were only positive in mammalian cell tests at concentrations between 1 and 10 mM. These carcinogens can be subdivided into four groups as follows: (1) probable non-genotoxic (non-mutagenic) carcinogens, tumour promoters or negative for genotoxicity in vivo (n=10); (2) questionable carcinogens (n=4); (3) carcinogens with a probable genotoxic mode of action (n=5); (4) compounds where carcinogenicity or in vivo genotoxicity is unknown or unclear (n=5). It is not expected that in vitro mammalian cell tests should give positive results with Group 1 chemicals. Within Groups 2-4, five chemicals were considered a low priority because they could be detected using modified conditions because genotoxicity was associated with precipitate or pH shifts or because non-standard metabolism was required. The remaining nine chemicals were therefore considered most critical in terms of detection of genotoxic activity in mammalian cells. Daminozide was also included because it may have given positive responses between 1 and 10 mM. Many of the reported studies could have given positive results only at >1 mM because 'old' protocols were followed. These 10 chemicals have therefore been retested using modern protocols. Some were negative even up to 10 mM. Others were positive at concentrations <1 mM. Only methylolacrylamide was positive at a concentration >1 mM (2 mM = 202 μg/ml). Low-molecular weight substances may therefore require concentrations >1 mM, but further work is needed. Based on this analysis, it is concluded that the 10 mM upper limit in mammalian cell tests can be lowered without any loss of sensitivity in detecting genotoxic rodent carcinogens. A new limit of 1 mM or 500 μg/ml, whichever is the higher, is proposed.

Assessment of genotoxicity of herbal medicinal products: application of the "bracketing and matrixing" concept using the example of Valerianae radix (valerian root).

PubMed

Kelber, Olaf; Wegener, Tankred; Steinhoff, Barbara; Staiger, Christiane; Wiesner, Jacqueline; Knöss, Werner; Kraft, Karin

2014-01-01

An assessment of genotoxicity is a precondition for marketing authorization respectively registration of herbal medicinal products (HMPs), as well as for inclusion into the 'Community list of herbal substances, preparations and combinations thereof for use in traditional herbal medicinal products' established by the European Commission in accordance with Directive 2001/83/EC as amended, and based on proposals from the Committee on Herbal Medicinal Products (HMPC). In the 'Guideline on the assessment of genotoxicity of herbal substances/preparations' (EMEA/HMPC/107079/2007) HMPC has described a stepwise approach for genotoxicity testing, according to which the Ames test is a sufficient base for the assessment of genotoxicity in case of an unequivocally negative result. For reducing efforts for testing of individual herbal substances/preparations, HMPC has also developed the 'guideline on selection of test materials for genotoxicity testing for traditional herbal medicinal products/herbal medicinal products' (EMEA/HMPC/67644/2009) with the aim to allow testing of a standard range of test materials which could be considered representative of the commonly used preparations from a specific herbal drug according to a 'bracketing/matrixing' approach. The purpose of this paper is to provide data on the practical application of this bracketing and matrixing concept using the example of Valerianae radix, with the intention of facilitating its inclusion in the "Community list". Five extraction solvents, representing the extremes of the polarity range and including also mid-range extraction solvents, were used, covering the entire spectrum of phytochemical constituents of Valerianae radix, thereby including polar and non-polar constituents. Extracts were tested in the Ames test according to all relevant guidelines. Results were unequivocally negative for all extracts. A review of the literature showed that this result is in accordance with the available data, thus demonstrating the lack of a genotoxic potential. In conclusion the two guidelines on genotoxicity provide a practically applicable concept. Valerianae radix has no genotoxic potential, supporting its use in HMPs and its inclusion in the Community list. Copyright © 2014 The Authors. Published by Elsevier GmbH.. All rights reserved.

Whole cell bioreporter application for rapid detection and evaluation of crude oil spill in seawater caused by Dalian oil tank explosion.

PubMed

Zhang, Dayi; Ding, Aizhong; Cui, Shuangchao; Hu, Cheng; Thornton, Steven F; Dou, Junfeng; Sun, Yujiao; Huang, Wei E

2013-03-01

Accidents involving the release of crude oil to seawater pose serious threat to human and animal health, fisheries and marine ecosystems. A whole cell bioreporter detection method, which has unique advantages for the rapid evaluation on toxicity and bioavailability, is a useful tool to provide environmental risk assessments at crude oil-contaminated sites. Acinetobacter baylyi ADPWH_alk and ADPWH_recA are chromosomally-based alkane and genotoxicity bioreporters which can be activated to express bioluminescence in the presence of alkanes and genotoxic compounds. In this study, we applied Acinetobacter ADPWH_alk and ADPWH_recA bioreporters to examine six seawater and six sediment samples around the Dalian Bay four weeks after an oil tank explosion in Dalian, China in 2010, and compared the results with samples from the same sites one year after. The results of bioreporter detection suggest that seawater and sediments from five sites (DB, NT, JSB, XHP and FJZ) four weeks after the oil-spill were contaminated by the crude oil with various extents of genotoxicity. Among these six sites, DB and NT had high oil contents and genotoxicity, and JSB had high oil content but low genotoxicity in comparison with an uncontaminated site LSF, which is located at other side of the peninsula. These three sites (DB, NT and JSB) with detectable genotoxicity are within 30 km away from the oil spill point. The far-away two sites XHP (38.1 km) and FJZ (31.1 km) were lightly contaminated with oil but no genotoxicity suggesting that they are around the contamination boundary. Bioreporter detection also indicates that all six sites were clean one year after the oil-spill as the alkane and genotoxicity were below detection limit. This study demonstrates that bioreporter detection can be used as a rapid method to estimate the scale of a crude oil spill accident and to evaluate bioavailability and genotoxicity of contaminated seawater and sediments, which are crucial to risk assessment and strategic decision-making for environmental management and clean-up. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inhalation of methane preserves the epithelial barrier during ischemia and reperfusion in the rat small intestine.

PubMed

Mészáros, András T; Büki, Tamás; Fazekas, Borbála; Tuboly, Eszter; Horváth, Kitti; Poles, Marietta Z; Szűcs, Szilárd; Varga, Gabriella; Kaszaki, József; Boros, Mihály

2017-06-01

Methane is part of the gaseous environment of the intestinal lumen. The purpose of this study was to elucidate the bioactivity of exogenous methane on the intestinal barrier function in an antigen-independent model of acute inflammation. Anesthetized rats underwent sham operation or 45-min occlusion of the superior mesenteric artery. A normoxic methane (2.2%)-air mixture was inhaled for 15 min at the end of ischemia and at the beginning of a 60-min or 180-min reperfusion. The integrity of the epithelial barrier of the ileum was assessed by determining the lumen-to-blood clearance of fluorescent dextran, while microvascular permeability changes were detected by the Evans blue technique. Tissue levels of superoxide, nitrotyrosine, myeloperoxidase, and endothelin-1 were measured, the superficial mucosal damage was visualized and quantified, and the serosal microcirculation and mesenteric flow was recorded. Erythrocyte deformability and aggregation were tested in vitro. Reperfusion significantly increased epithelial permeability, worsened macro- and microcirculation, increased the production of proinflammatory mediators, and resulted in a rapid loss of the epithelium. Exogenous normoxic methane inhalation maintained the superficial mucosal structure, decreased epithelial permeability, and improved local microcirculation, with a decrease in reactive oxygen and nitrogen species generation. Both the deformability and aggregation of erythrocytes improved with incubation of methane. Normoxic methane decreases the signs of oxidative and nitrosative stress, improves tissue microcirculation, and thus appears to modulate the ischemia-reperfusion-induced epithelial permeability changes. These findings suggest that the administration of exogenous methane may be a useful strategy for maintaining the integrity of the mucosa sustaining an oxido-reductive attack. Copyright © 2017 Elsevier Inc. All rights reserved.

Raw data of the effects of Chlorogenic acid in 3-Nitropropionic acid induced toxicity and genotoxicity.

PubMed

Norberto, Alarcón-Herrera; Saúl, Flores-Maya; Belén, Bellido; García-Bores Ana, M; Ernesto, Mendoza; Guillermo, Ávila-Acevedo; Elizabeth, Hernández-Echeagaray

2017-10-01

The raw data showed in this article comes from the published research article entitled "Protective effects of Chlorogenic acid in 3-Nitropropionic acid induced toxicity and genotoxicity" Food Chem Toxicol. 2017 May 3. pii: S0278-6915(17)30226-0. DOI:10.1016/j.fct.2017.04.048. [1]. Data illustrates antitoxic and antigenotoxic effects of Chlorogenic acid (CGA) on toxicity and genotoxicity produced by the in vivo treatment with mitochondria toxin 3-Nitropropionic acid (3-NP) in mice. Toxicity and genotoxicity was evaluated in erythrocytes of peripheral blood through the micronuclei assay. Data was share at the Elsevier repository under the reference number FCT9033.

Antigenotoxic and free radical scavenging activities of extracts from Moricandia arvensis.

PubMed

Skandrani, I; Sghaier, M Ben; Neffati, A; Boubaker, J; Bouhlel, I; Kilani, S; Mahmoud, A; Ghedira, K; Chekir-Ghedira, L

2007-01-01

This study evaluates genotoxic and antigenotoxic effects of extracts from leaves of Moricandia arvensis, which are used in traditional cooking and medicines. Extracts showed no genotoxicity when tested with the SOS Chromotest using E. coli PQ37 and PQ35 strains, except for the total oligomers flavonoids enriched extract. Petroleum ether and methanol extracts are the most active in reducing nitrofurantoin genotoxicity, whereas methanol and total oligomers flavonoids enriched extracts showed the most important inhibitory effect of H2O2 genotoxicity. In addition, these two extracts showed important free radical scavenging activity toward the DPPH. radical, whereas the chloroform extract exhibited the highest value of TEAC against ABTS+. radical.

Biological importance of reactive oxygen species in relation to difficulties of treating pathologies involving oxidative stress by exogenous antioxidants.

PubMed

Juránek, Ivo; Nikitovic, Dragana; Kouretas, Dimitrios; Hayes, A Wallace; Tsatsakis, Aristidis M

2013-11-01

Findings about involvement of reactive oxygen species (ROS) not only in defense processes, but also in a number of pathologies, stimulated discussion about their role in etiopathogenesis of various diseases. Yet questions regarding the role of ROS in tissue injury, whether ROS may serve as a common cause of different disorders or whether their uncontrolled production is just a manifestation of the processes involved, remain unexplained. Dogmatically, increased ROS formation is considered to be responsible for development of the so-called free-radical diseases. The present review discusses importance of ROS in various biological processes, including origin of life, evolution, genome plasticity, maintaining homeostasis and organism protection. This may be a reason why no significant benefit was found when exogenous antioxidants were used to treat free-radical diseases, even though their causality was primarily attributed to ROS. Here, we postulate that ROS unlikely play a causal role in tissue damage, but may readily be involved in signaling processes and as such in mediating tissue healing rather than injuring. This concept is thus in a contradiction to traditional understanding of ROS as deleterious agents. Nonetheless, under conditions of failing autoregulation, ROS may attack integral cellular components, cause cell death and deteriorate the evolving injury. Copyright © 2013 Elsevier Ltd. All rights reserved.

Use of the microscreen phage-induction assay to assess the genotoxicity of 14 hazardous industrial wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1988-01-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s(lambda), was used to test 14 crude (unfractionated) hazardous industrial waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 pg per ml. Comparisons between the ability of these waste samples to induce prophage and their mutagenicity in the Salmonella reverse mutation assay indicate that the phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, themore » Microscreen assay detected as genotoxic five additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed, as are some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less

Use of the Microscreen phage-induction assay to assess the genotoxicity of 14 hazardous industrial wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1988-01-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s lambda, was used to test 14 crude (unfractionated) hazardous industrial-waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons between the mutagenicity of these waste samples in Salmonella and their ability to induce prophage lambda indicate that the Microscreen phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, the Microscreen assaymore » detected as genotoxic 5 additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed along with some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less

Linking genotoxic responses and reproductive success in ecotoxicology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, S.L.; Wild, G.C.

1994-12-01

The potential of genotoxicity biomarkers as predictors of detrimental environmental effects, such as altered reproductive success of wild organisms, must be rigorously determined. Recent research to evaluate relationships between genotoxic responses and indicators of reproductive success in model animals is described from an ecotoxicological perspective. Genotoxicity can be correlated with reproductive effects such as gamete loss due to cell death; embryonic mortality; and heritable mutations in a range of model animals including polychaete worms, nematodes, sea urchins, amphibians, and fish. In preliminary studies, the polychaete worm, Neanthes arenaceodentata, and the nematode, Caenorhabditis elegans, have also shown the potential for cumulativemore » DNA damage in gametes. If DNA repair capacity is limited in gametes, then selected life history traits such as long and synchronous periods of gametogenesis may confer vulnerability to genotoxic substances in chronic exposures. Recommendations for future research include strategic development of animal models that can be used to elucidate multiple mechanisms of effect (multiend point) at varying levels of biological organization (multilevel). 27 refs., 2 tabs.« less

Setting Occupational Exposure Limits for Genotoxic Substances in the Pharmaceutical Industry.

PubMed

Lovsin Barle, Ester; Winkler, Gian Christian; Glowienke, Susanne; Elhajouji, Azeddine; Nunic, Jana; Martus, Hans-Joerg

2016-05-01

In the pharmaceutical industry, genotoxic drug substances are developed for life-threatening indications such as cancer. Healthy employees handle these substances during research, development, and manufacturing; therefore, safe handling of genotoxic substances is essential. When an adequate preclinical dataset is available, a risk-based decision related to exposure controls for manufacturing is made following a determination of safe health-based limits, such as an occupational exposure limit (OEL). OELs are calculated for substances based on a threshold dose-response once a threshold is identified. In this review, we present examples of genotoxic mechanisms where thresholds can be demonstrated and OELs can be calculated, including a holistic toxicity assessment. We also propose a novel approach for inhalation Threshold of Toxicological Concern (TTC) limit for genotoxic substances in cases where the database is not adequate to determine a threshold. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Cytotoxic and genotoxic potential of food-borne nitriles in a liver in vitro model

PubMed Central

Kupke, Franziska; Herz, Corinna; Hanschen, Franziska S.; Platz, Stefanie; Odongo, Grace A.; Helmig, Simone; Bartolomé Rodríguez, María M.; Schreiner, Monika; Rohn, Sascha; Lamy, Evelyn

2016-01-01

Isothiocyanates are the most intensively studied breakdown products of glucosinolates from Brassica plants and well recognized for their pleiotropic effects against cancer but also for their genotoxic potential. However, knowledge about the bioactivity of glucosinolate-borne nitriles in foods is very poor. As determined by GC-MS, broccoli glucosinolates mainly degrade to nitriles as breakdown products. The cytotoxicity of nitriles in human HepG2 cells and primary murine hepatocytes was marginal as compared to isothiocyanates. Toxicity of nitriles was not enhanced in CYP2E1-overexpressing HepG2 cells. In contrast, the genotoxic potential of nitriles was found to be comparable to isothiocyanates. DNA damage was persistent over a certain time period and CYP2E1-overexpression further increased the genotoxic potential of the nitriles. Based on actual in vitro data, no indications are given that food-borne nitriles could be relevant for cancer prevention, but could pose a certain genotoxic risk under conditions relevant for food consumption. PMID:27883018

Genotoxicity of lapachol evaluated by wing spot test of Drosophila melanogaster

PubMed Central

2010-01-01

This study investigated the genotoxicity of Lapachol (LAP) evaluated by wing spot test of Drosophila melanogaster in the descendants from standard (ST) and high bioactivation (HB) crosses. This assay detects the loss of heterozygosity of marker genes expressed phenotypically on the fly's wings. Drosophila has extensive genetic homology to mammals, which makes it a suitable model organism for genotoxic investigations. Three-day-old larvae from ST crosses (females flr3/TM3, Bds x males mwh/mwh), with basal levels of the cytochrome P450 and larvae of high metabolic bioactivity capacity (HB cross) (females ORR; flr3/TM3, Bds x males mwh/mwh), were used. The results showed that LAP is a promutagen, exhibiting genotoxic activity in larvae from the HB cross. In other words, an increase in the frequency of spots is exclusive of individuals with a high level of the cytochrome P450. The results also indicate that recombinogenicity is the main genotoxic event induced by LAP. PMID:21637432

Genotoxicity of Water Contaminants from the Basin of Lake Sevan, Armenia Evaluated by the Comet Assay in Gibel Carp (Carassius auratus gibelio) and Tradescantia Bioassays.

PubMed

Simonyan, Anna; Gabrielyan, Barduch; Minasyan, Seyran; Hovhannisyan, Galina; Aroutiounian, Rouben

2016-03-01

Combination of bioassays and chemical analysis was applied to determine the genotoxic/mutagenic contamination in four different sites of the basin of Lake Sevan in Armenia. Water genotoxicity was evaluated using the single cell gel electrophoresis technique (comet assay) in erythrocytes of gibel carp (Carassius auratus gibelio), Tradescantia micronucleus (Trad-MCN) and Tradescantia stamen hair mutation (Trad-SHM) assays. Significant inter-site differences in the levels of water genotoxicity according to fish and Trad-MCN bioassays have been revealed. Two groups of locations with lower (south-southwest of the village Shorzha and Peninsula of Lake Sevan) and higher (estuaries of Gavaraget and Dzknaget rivers) levels of water genotoxicity were distinguished. Correlation analysis support the hypothesis that the observed genetic alterations in fish and plant may be a manifestation of the effects of water contamination by nitrate ions, Si, Al, Fe, Mn and Cu. Increase of DNA damage in fish also correlated with content of total phosphorus.

Bioassessment of the Effluents Discharged from Two Export Oriented Industrial Zones Located in Kelani River Basin, Sri Lanka Using Erythrocytic Responses of the Fish, Nile Tilapia (Oreochromis niloticus).

PubMed

Hemachandra, C K; Pathiratne, A

2017-10-01

Complex effluents originating from diverse industrial processes in industrial zones could pose cytotoxic/genotoxic hazards to biota in the receiving ecosystems which cannot be revealed by conventional monitoring methods. This study assessed potential cytotoxicity/genotoxicity of treated effluents of two industrial zones which are discharged into Kelani river, Sri Lanka combining erythrocytic abnormality tests and comet assay of the tropical model fish, Nile tilapia. Exposure of fish to the effluents induced erythrocytic DNA damage and deformed erythrocytes with serrated membranes, vacuolations, nuclear buds and micronuclei showing cytotoxic/genotoxic hazards in all cases. Occasional exceedance of industrial effluent discharge regulatory limits was noted for color and lead which may have contributed to the observed cytotoxicity/genotoxicity of effluents. The results demonstrate that fish erythrocytic responses could be used as effective bioanalytical tools for cytotoxic/genotoxic hazard assessments of complex effluents of industrial zones for optimization of the waste treatment process in order to reduce biological impacts.

Modulation of mitomycin C-induced genotoxicity by acetyl- and thio- analogues of salicylic acid.

PubMed

Pawar, Amol Ashok; Vikram, Ajit; Tripathi, Durga Nand; Padmanabhan, Shweta; Ramarao, Poduri; Jena, Gopabandhu

2009-01-01

Recent reports regarding acetylsalicylic acid (ASA) and its metabolites suggest suppressive effects against mitomycin C (MMC)-induced genotoxicity in a mice chromosomal aberration assay. Keeping this in mind, the potential anti-genotoxic effect of the thio-analogue of salicylic acid namely thio-salicylic acid (TSA) was speculated upon. The present study investigated and compared the anti-genotoxic potential of ASA and TSA. The study was performed in male swiss mice (20+/-2 g) using single-cell gel electrophoresis and a peripheral blood micronucleus assay. ASA and TSA (5, 10 or 20 mg/kg) were administered 15 minutes after MMC (1 mg/kg) once daily for 3 or 7 days. Both ASA and TSA significantly decreased the DNA damage induced by MMC as indicated by a decrease in the comet parameters in bone marrow cells and decreased frequencies of micronucleated reticulocytes in peripheral blood. The results clearly demonstrate the anti-genotoxic potential of ASA and TSA.

Rapid Assessment of Genotoxicity by Flow Cytometric Detection of Cell Cycle Alterations.

PubMed

Bihari, Nevenka

2017-01-01

Flow cytometry is a convenient method for the determination of genotoxic effects of environmental pollution and can reveal genotoxic compounds in unknown environmental mixtures. It is especially suitable for the analyses of large numbers of samples during monitoring programs. The speed of detection is one of the advantages of this technique which permits the acquisition of 10 4 -10 5 cells per sample in 5 min. This method can rapidly detect cell cycle alterations resulting from DNA damage. The outcome of such an analysis is a diagram of DNA content across the cell cycle which indicates cell proliferation, G 2 arrests, G 1 delays, apoptosis, and ploidy.Here, we present the flow cytometric procedure for rapid assessment of genotoxicity via detection of cell cycle alterations. The described protocol simplifies the analysis of genotoxic effects in marine environments and is suitable for monitoring purposes. It uses marine mussel cells in the analysis and can be adapted to investigations on a broad range of marine invertebrates.

Genotoxicity of AMPA, the environmental metabolite of glyphosate, assessed by the Comet assay and cytogenetic tests.

PubMed

Mañas, F; Peralta, L; Raviolo, J; García Ovando, H; Weyers, A; Ugnia, L; Gonzalez Cid, M; Larripa, I; Gorla, N

2009-03-01

Formulations containing glyphosate are the most widely used herbicides in the world. AMPA is the major environmental breakdown product of glyphosate. The purpose of this study is to evaluate the in vitro genotoxicity of AMPA using the Comet assay in Hep-2 cells after 4h of incubation and the chromosome aberration (CA) test in human lymphocytes after 48h of exposition. Potential in vivo genotoxicity was evaluated through the micronucleus test in mice. In the Comet assay, the level of DNA damage in exposed cells at 2.5-7.5mM showed a significant increase compared with the control group. In human lymphocytes we found statistically significant clastogenic effect AMPA at 1.8mM compared with the control group. In vivo, the micronucleus test rendered significant statistical increases at 200-400mg/kg. AMPA was genotoxic in the three performed tests. Very scarce data are available about AMPA potential genotoxicity.

Chemical composition and antigenotoxic properties of Lippia alba essential oils

PubMed Central

López, Molkary Andrea; Stashenko, Elena E.; Fuentes, Jorge Luis

2011-01-01

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-β-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds. PMID:21931523

Chemical composition and antigenotoxic properties of Lippia alba essential oils.

PubMed

López, Molkary Andrea; Stashenko, Elena E; Fuentes, Jorge Luis

2011-07-01

The present work evaluated the chemical composition and the DNA protective effect of the essential oils (EOs) from Lippia alba against bleomycin-induced genotoxicity. EO constituents were determined by Gas Chromatography/Mass Spectrometric (GC-MS) analysis. The major compounds encountered being citral (33% geranial and 25% neral), geraniol (7%) and trans-β-caryophyllene (7%) for L. alba specimen COL512077, and carvone (38%), limonene (33%) and bicyclosesquiphellandrene (8%) for the other, COL512078. The genotoxicity and antigenotoxicity of EO and the compounds citral, carvone and limonene, were assayed using the SOS Chromotest in Escherichia coli. The EOs were not genotoxic in the SOS chromotest, but one of the major compound (limonene) showed genotoxicity at doses between 97 and 1549 mM. Both EOs protected bacterial cells against bleomycin-induced genotoxicity. Antigenotoxicity in the two L. alba chemotypes was related to the major compounds, citral and carvone, respectively. The results were discussed in relation to the chemopreventive potential of L. alba EOs and its major compounds.

Testing the genotoxicity of coking wastewater using Vicia faba and Hordeum vulgare bioassays.

PubMed

Dong, Yiru; Zhang, Jintun

2010-07-01

The coking wastewater induces severe environmental problems in China, however, its toxicity has not been well known. In the present study, the genotoxicity of coking wastewater was studied using Vicia faba and Hordeum vulgare root tip cytogenetic bioassays. Results show that the tested coking wastewater decreased the mitotic index, and significantly enhanced the frequencies of micronucleus, sister chromatid exchange and pycnotic cell in concentration-dependent manners. Exposure to the same concentration wastewater, the increasing ratios of above genetic injuries were higher in V. faba than that in H. vulgare. The results imply that coking wastewater is a genotoxic agent in plant cells and exposure to the wastewater in environment may pose a potential genotoxic risk to organisms. It also suggests that both bioassays can be used for testing the genotoxicity of coking wastewater, but the V. faba assay is more sensitive than H. vulgare assay during the process. Copyright (c) 2010. Published by Elsevier Inc.

A tiered approach to the use of alternatives to animal testing for the safety assessment of cosmetics: genotoxicity. A COLIPA analysis.

PubMed

Pfuhler, Stefan; Kirst, Annette; Aardema, Marilyn; Banduhn, Norbert; Goebel, Carsten; Araki, Daisuke; Costabel-Farkas, Margit; Dufour, Eric; Fautz, Rolf; Harvey, James; Hewitt, Nicola J; Hibatallah, Jalila; Carmichael, Paul; Macfarlane, Martin; Reisinger, Kerstin; Rowland, Joanna; Schellauf, Florian; Schepky, Andreas; Scheel, Julia

2010-01-01

For the assessment of genotoxic effects of cosmetic ingredients, a number of well-established and regulatory accepted in vitro assays are in place. A caveat to the use of these assays is their relatively low specificity and high rate of false or misleading positive results. Due to the 7th amendment to the EU Cosmetics Directive ban on in vivo genotoxicity testing for cosmetics that was enacted March 2009, it is no longer possible to conduct follow-up in vivo genotoxicity tests for cosmetic ingredients positive in in vitro genotoxicity tests to further assess the relevance of the in vitro findings. COLIPA, the European Cosmetics Association, has initiated a research programme to improve existing and develop new in vitro methods. A COLIPA workshop was held in Brussels in April 2008 to analyse the best possible use of available methods and approaches to enable a sound assessment of the genotoxic hazard of cosmetic ingredients. Common approaches of cosmetic companies are described, with recommendations for evaluating in vitro genotoxins using non-animal approaches. A weight of evidence approach was employed to set up a decision-tree for the integration of alternative methods into tiered testing strategies. Copyright 2010 Elsevier Inc. All rights reserved.

Genotoxicity testing of Persicariae Rhizoma (Persicaria tinctoria H. Gross) aqueous extracts

PubMed Central

LEE, WON HO; CHOI, SEONG HUN; KANG, SU JIN; SONG, CHANG HYUN; PARK, SOO JIN; LEE, YOUNG JOON; KU, SAE KWANG

2016-01-01

Persicariae Rhizoma (PR) has been used as an anti-inflammatory and detoxification agent in Korea, and contains the biologically active dyes purple indirubin and blue indigo. Despite synthetic indigo showing genotoxic potential, thorough studies have not been carried out on the genotoxicity of PR. The potential genotoxicity of an aqueous extract of PR containing indigo (0.043%) and indirubin (0.009%) was evaluated using a standard battery of tests for safety assessment. The PR extract did not induce any genotoxic effects under the conditions of this study. The results of a reverse mutation assay in four Salmonella typhimurium strains and one Escherichia coli strain indicated that PR extract did not increase the frequency of revertant colonies in any strain, regardless of whether S9 mix was present or not. The PR extract also did not increase chromosomal aberrations in the presence or absence of S9 mix. Although slight signs of diarrhea were restrictedly detected in the mice treated with 2,000 mg/kg PR extract, no noteworthy changes in the frequency of micronucleated polychromatic erythrocytes were observed at doses ≤2,000 mg/kg in a bone marrow micronucleus test. These results indicate the potential safety of the PR extract, particularly if it is consumed in small amounts compared with the quantities used in the genotoxicity tests. PMID:27347027

Protective effects of chlorogenic acid in 3-nitropropionic acid induced toxicity and genotoxicity.

PubMed

Alarcón-Herrera, Norberto; Flores-Maya, Saúl; Bellido, Belén; García-Bores, Ana M; Mendoza, Ernesto; Ávila-Acevedo, Guillermo; Hernández-Echeagaray, Elizabeth

2017-11-01

Mitochondrial inhibition with the toxin 3-Nitropropionic acid (3-NP) has been used to study the underlying mechanisms in striatal neurodegeneration, but few experiments have evaluated its toxicity and genotoxicity of in vivo administration. Furthermore, different antioxidant molecules may prevent degeneration induced by the toxic effects of 3-NP. Therefore, the purpose of this study was to evaluate the toxicity and genotoxicity induced by 3-NP (15 mg/kg) in the micronuclei assay method; also, we assessed chlorogenic acid (CGA, 100 mg/kg) for its anti-toxic and anti-genotoxic effect in damage produced by in vivo treatment with 3-NP. 3-NP induced toxicity and genotoxicity. CGA administered as a co-treatment with 3-NP (3-NP + CA) reduced toxicity by 32.76%, as a pre-treatment for 5 days only, followed by 3-NP treatment (P/CA, 3-NP) inhibiting toxicity by 24.04%, or as a pre-treatment, plus a co-treatment with 3-NP (P/CA, 3-NP + CA) avoided any toxic effect. CGA alone did not exhibit any toxic effect. Only P/CGA, 3-NP + CGA group, avoided toxicity and genotoxicity, suggesting that CGA could be suitable to prevent, reduce or delay toxicity and cell death. Copyright © 2017 Elsevier Ltd. All rights reserved.

Micronucleated Erythrocytes in Peripheral Blood from Neonate Rats Exposed by Breastfeeding to Cyclophosphamide, Colchicine, or Cytosine-Arabinoside.

PubMed

Gómez-Meda, Belinda C; Bañales-Martínez, Luis R; Zamora-Perez, Ana L; Lemus-Varela, María de Lourdes; Trujillo, Xóchitl; Sánchez-Parada, María G; Torres-Mendoza, Blanca M; Armendáriz-Borunda, Juan; Zúñiga-González, Guillermo M

2016-01-01

Genotoxic exposure to chemical substances is common, and nursing mothers could transmit harmful substances or their metabolites to their offspring through breast milk. We explored the possibility of determining genotoxic effects in the erythrocytes of breastfeeding rat pups whose mothers received a genotoxic compound while nursing. Ten groups of female rats and five pups per dam were studied. The control group received sterile water, and the experimental groups received one of three different doses of cyclophosphamide, colchicine, or cytosine-arabinoside. Blood smears were prepared from samples taken from each dam and pup every 24 h for six days. There were increased numbers of micronucleated erythrocytes (MNEs) and micronucleated polychromatic erythrocytes (MNPCEs) in the samples from pups in the experimental groups ( P < 0.02) and increased MNPCE frequencies in the samples from the dams ( P < 0.05). These results demonstrate the vertical transmission of the genotoxic effect of the compounds tested. In conclusion, assessing MNEs in breastfeeding neonate rats to assess DNA damage may be a useful approach for identifying genotoxic compounds and/or cytotoxic effects. This strategy could help in screening for therapeutic approaches that are genotoxic during the lactation stage and these assessments might also be helpful for developing preventive strategies to counteract harmful effects.

Micronucleated Erythrocytes in Peripheral Blood from Neonate Rats Exposed by Breastfeeding to Cyclophosphamide, Colchicine, or Cytosine-Arabinoside

PubMed Central

Bañales-Martínez, Luis R.; Lemus-Varela, María de Lourdes; Trujillo, Xóchitl; Sánchez-Parada, María G.; Armendáriz-Borunda, Juan; Zúñiga-González, Guillermo M.

2016-01-01

Genotoxic exposure to chemical substances is common, and nursing mothers could transmit harmful substances or their metabolites to their offspring through breast milk. We explored the possibility of determining genotoxic effects in the erythrocytes of breastfeeding rat pups whose mothers received a genotoxic compound while nursing. Ten groups of female rats and five pups per dam were studied. The control group received sterile water, and the experimental groups received one of three different doses of cyclophosphamide, colchicine, or cytosine-arabinoside. Blood smears were prepared from samples taken from each dam and pup every 24 h for six days. There were increased numbers of micronucleated erythrocytes (MNEs) and micronucleated polychromatic erythrocytes (MNPCEs) in the samples from pups in the experimental groups (P < 0.02) and increased MNPCE frequencies in the samples from the dams (P < 0.05). These results demonstrate the vertical transmission of the genotoxic effect of the compounds tested. In conclusion, assessing MNEs in breastfeeding neonate rats to assess DNA damage may be a useful approach for identifying genotoxic compounds and/or cytotoxic effects. This strategy could help in screening for therapeutic approaches that are genotoxic during the lactation stage and these assessments might also be helpful for developing preventive strategies to counteract harmful effects. PMID:28018917

Differential toxicity of drinking water disinfected with combinations of ultraviolet radiation and chlorine.

PubMed

Plewa, Michael J; Wagner, Elizabeth D; Metz, Deborah H; Kashinkunti, Ramesh; Jamriska, Katherine J; Meyer, Maria

2012-07-17

Alternative technologies to disinfect drinking water such as ultraviolet (UV) disinfection are becoming more widespread. The benefits of UV disinfection include reduced risk of microbial pathogens such as Cryptosporidium and reduced production of regulated drinking water disinfection byproducts (DBPs). The objective of this research was to determine if mammalian cell cytotoxicity and genotoxicity varied in response to different chlorination protocols with and without polychromatic medium pressure UV (MPUV) and monochromatic low pressure UV (LPUV) disinfection technologies. The specific aims were to analyze the mammalian cell cytotoxicity and genotoxicity of concentrated organic fractions from source water before and after chlorination and to determine the cytotoxicity and genotoxicity of the concentrated organic fractions from water samples treated with UV alone or UV before or after chlorination. Exposure of granular activated carbon-filtered Ohio River water to UV alone resulted in the lowest levels of mammalian cell cytotoxicity and genotoxicity. With combinations of UV and chlorine, the lowest levels of cytotoxicity and genotoxicity were observed with MPUV radiation. The best combined UV plus chlorine methodology that generated the lowest cytotoxicity and genotoxicity employed chlorination first followed by MPUV radiation. These data may prove important in the development of multibarrier methods of pathogen inactivation of drinking water, while limiting unintended toxic consequences.

Assessment of Genotoxic Potential of Hridayarnava Rasa (A Herbo-Mineralo-Metallic Ayurvedic Formulation) Using Chromosomal Aberration and Sperm Abnormality Assays

PubMed Central

Jagtap, Chandrashekhar Y.; Chaudhari, Swapnil Y.; Thakkar, Jalaram H.; Galib, R.; Prajapati, P. K.

2014-01-01

Objectives: Herbo-mineral formulations are being successfully used in therapeutics since centuries. But recently, they came under the scanner for their metallic contents especially the presence of heavy metals. Hence it is the need of the hour to assess and establish the safety of these formulations through toxicity studies. In line with the various toxicity studies that are being carried out, Government of India expressed the need for conducting genotoxicity studies of different metal- or mineral-based drugs. Till date very few Ayurvedic herbo-mineral formulations have been studied for their genotoxic potential. The present study is aimed to evaluate the genotoxic potential of Hridayarnava Rasa. Materials and Methods: It was prepared as per classical guidelines and administered to Swiss albino mice for 14 consecutive days. Chromosomal aberration and sperm abnormality assay were done to evaluate the genotoxic potential of the test drugs. Cyclophosphamide (CP) was taken as positive group and results were compared. Results: All treated groups exhibited significant body weight gain in comparison to CP group. Results revealed no structural deformity in the above parameters in comparison to the CP-treated group. Conclusion: Reported data showed that both tested samples of Hridayarnava Rasa does not possess genotoxic potential under the experimental conditions and can be safely used. PMID:25948961

Evaluation of genotoxicity testing of FDA approved large molecule therapeutics.

PubMed

Sawant, Satin G; Fielden, Mark R; Black, Kurt A

2014-10-01

Large molecule therapeutics (MW>1000daltons) are not expected to enter the cell and thus have reduced potential to interact directly with DNA or related physiological processes. Genotoxicity studies are therefore not relevant and typically not required for large molecule therapeutic candidates. Regulatory guidance supports this approach; however there are examples of marketed large molecule therapeutics where sponsors have conducted genotoxicity studies. A retrospective analysis was performed on genotoxicity studies of United States FDA approved large molecule therapeutics since 1998 identified through the Drugs@FDA website. This information was used to provide a data-driven rationale for genotoxicity evaluations of large molecule therapeutics. Fifty-three of the 99 therapeutics identified were tested for genotoxic potential. None of the therapeutics tested showed a positive outcome in any study except the peptide glucagon (GlucaGen®) showing equivocal in vitro results, as stated in the product labeling. Scientific rationale and data from this review indicate that testing of a majority of large molecule modalities do not add value to risk assessment and support current regulatory guidance. Similarly, the data do not support testing of peptides containing only natural amino acids. Peptides containing non-natural amino acids and small molecules in conjugated products may need to be tested. Copyright © 2014 Elsevier Inc. All rights reserved.

The application of structure-based assessment to support safety and chemistry diligence to manage genotoxic impurities in active pharmaceutical ingredients during drug development.

PubMed

Dobo, Krista L; Greene, Nigel; Cyr, Michelle O; Caron, Stéphane; Ku, Warren W

2006-04-01

Starting materials and intermediates used to synthesize pharmaceuticals are reactive in nature and may be present as impurities in the active pharmaceutical ingredient (API) used for preclinical safety studies and clinical trials. Furthermore, starting materials and intermediates may be known or suspected mutagens and/or carcinogens. Therefore, during drug development due diligence need be applied from two perspectives (1) to understand potential mutagenic and carcinogenic risks associated with compounds used for synthesis and (2) to understand the capability of synthetic processes to control genotoxic impurities in the API. Recently, a task force comprised of experts from pharmaceutical industry proposed guidance, with recommendations for classification, testing, qualification and assessing risk of genotoxic impurities. In our experience the proposed structure-based classification, has differentiated 75% of starting materials and intermediates as mutagenic and non-mutagenic with high concordance (92%) when compared with Ames results. Structure-based assessment has been used to identify genotoxic hazards, and prompted evaluation of fate of genotoxic impurities in API. These two assessments (safety and chemistry) culminate in identification of genotoxic impurities known or suspected to exceed acceptable levels in API, thereby triggering actions needed to assure appropriate control and measurement methods are in place. Hypothetical case studies are presented demonstrating this multi-disciplinary approach.

Genotoxicity reduction in bagasse waste of sugar industry by earthworm technology.

PubMed

Bhat, Sartaj Ahmad; Singh, Jaswinder; Vig, Adarsh Pal

2016-01-01

The aim of the present study was to assess the genotoxicity reduction in post vermicompost feed mixtures of bagasse (B) waste using earthworm Eisenia fetida. The genotoxicity of bagasse waste was determined by using Allium cepa root chromosomal aberration assay. Bagasse was amended with cattle dung in different proportions [0:100 (B0) 25:75 (B25), 50:50 (B50), 75:25 (B75) and 100:0 (B100)] on dry weight basis. Genotoxic effects of initial and post vermicompost bagasse extracts were analysed on the root tips cells of Allium cepa. Root length and mitotic index (MI) was found to be increased in post vermicompost extracts when compared to initial bagasse waste. The maximum percent increase of root length was observed in the B50 bagasse extract (96.60 %) and the maximum MI was observed in B100 mixture (14.20 ± 0.60) 6 h treatment which was similar to the control. Genotoxicity analysis of post vermicompost extracts of bagasse revealed a 21-44 % decline in the aberration frequencies and the maximum reduction was found in B75 extract (44.50 %). The increase in root length and mitotic index, as well as decrease in chromosomal aberrations indicates that E. fetida has the ability to reduce the genotoxicity of the bagasse waste.

A re-assessment of the safety of silver in household water treatment: rapid systematic review of mammalian in vivo genotoxicity studies.

PubMed

Fewtrell, Lorna; Majuru, Batsirai; Hunter, Paul R

2017-06-20

Despite poor evidence of their effectiveness, colloidal silver and silver nanoparticles are increasingly being promoted for treating potentially contaminated drinking water in low income countries. Recently, however, concerns have been raised about the possible genotoxicity of particulate silver. The goal of this paper was to review the published mammalian in vivo genotoxicity studies using silver micro and nanoparticles. SCOPUS and Medline were searched using the following search string: ("DNA damage" OR genotox* OR Cytotox* OR Embryotox*) AND (silver OR AgNP). Included papers were any mammalian in vivo experimental studies investigating genotoxicity of silver particles. Studies were quality assessed using the ToxRTool. 16 relevant papers were identified. There were substantial variations in study design including the size of silver particles, animal species, target organs, silver dose, route of administration and the method used to detect genotoxicity. Thus, it was not possible to produce a definitive pooled result. Nevertheless, most studies showed evidence of genotoxicity unless using very low doses. We also identified one human study reporting evidence of "severe DNA damage" in silver jewellery workers occupationally exposed to silver particles. With the available evidence it is not possible to be definitive about risks to human health from oral exposure to silver particulates. However, the balance of evidence suggests that there should be concerns especially when considering the evidence from jewellery workers. There is an urgent need to determine whether people exposed to particulate silver as part of drinking water treatment have evidence of DNA damage.

In Vitro Analysis of Early Genotoxic and Cytotoxic Effects of Okadaic Acid in Different Cell Types of the Mussel Mytilus galloprovincialis.

PubMed

Prego-Faraldo, María Verónica; Valdiglesias, Vanessa; Laffon, Blanca; Eirín-López, José M; Méndez, Josefina

2015-01-01

Okadaic acid (OA) is the predominant biotoxin responsible for diarrhetic shellfish poisoning (DSP) syndrome in humans. While its harmful effects have been extensively studied in mammalian cell lines, the impact on marine organisms routinely exposed to OA is still not fully known. Few investigations available on bivalve molluscs suggest less genotoxic and cytotoxic effects of OA at high concentrations during long exposure times. In contrast, no apparent information is available on how sublethal concentrations of OA affect these organisms over short exposure times. In order to fill this gap, this study addressed for the first time in vitro analysis of early genotoxic and cytotoxic effects attributed to OA in two cell types of the mussel Mytilus galloprovincialis. Accordingly, hemocytes and gill cells were exposed to low OA concentrations (10, 50, 100, 200, or 500 nM) for short periods of time (1 or 2 h). The resulting DNA damage, as apoptosis and necrosis, was subsequently quantified using the comet assay and flow cytometry, respectively. Data demonstrated that (1) mussel hemocytes seem to display a resistance mechanism against early genotoxic and cytotoxic OA-induced effects, (2) mussel gill cells display higher sensitivity to early OA-mediated genotoxicity than hemocytes, and (3) mussel gill cells constitute more suitable systems to evaluate the genotoxic effect of low OA concentrations in short exposure studies. Taken together, this investigation provides evidence supporting the more reliable suitability of mussel gill cells compared to hemocytes to evaluate the genotoxic effect of low short-duration exposure to OA.

Tungsten carbide-cobalt as a nanoparticulate reference positive control in in vitro genotoxicity assays.

PubMed

Moche, Hélène; Chevalier, Dany; Barois, Nicolas; Lorge, Elisabeth; Claude, Nancy; Nesslany, Fabrice

2014-01-01

With the increasing human exposure to nanoparticles (NP), the evaluation of their genotoxic potential is of significant importance. However, relevance for NP of the routinely used in vitro genotoxicity assays is often questioned, and a nanoparticulate reference positive control would therefore constitute an important step to a better testing of NP, ensuring that test systems are really appropriate. In this study, we investigated the possibility of using tungsten carbide-cobalt (WC-Co) NP as reference positive control in in vitro genotoxicity assays, including 2 regulatory assays, the mouse lymphoma assay and the micronucleus assay, and in the Comet assay, recommended for the toxicological evaluation of nanomedicines by the French Agency of Human Health Products (Afssaps). Through these assays, we were able to study different genetic endpoints in 2 cell types commonly used in regulatory genotoxicity assays: the L5178Y mouse lymphoma cell line and primary cultures of human lymphocytes. Our results showed that the use of WC-Co NP as positive control in in vitro genotoxicity assays was conceivable, but that different parameters have to be considered, such as cell type and treatment schedule. L5178Y mouse lymphoma cells did not provide satisfactory results in the 3 performed tests. However, human lymphocytes were more sensitive to genotoxic effects induced by WC-Co NP, particularly after a 24-h treatment in the in vitro micronucleus assay and after a 4-h treatment in the in vitro Comet assay. Under such conditions, WC-Co could be used as a nanoparticulate reference positive control in these assays.

Application of bacterial reverse mutation assay for detection of non-genotoxic carcinogens.

PubMed

Kanode, Rewan; Chandra, Saurabh; Sharma, Sharad

2017-06-01

Non-genotoxic carcinogens may play a significant role in development of cancer. Currently short-term assays for mutagenicity classify genotoxic carcinogens and lack the abilities to detect epigenetic carcinogens. The need to develop an endpoint always remains to recognize potentially carcinogenic agents employing rapid and practical bioassays. For this, the present study utilized TA98 and TA1537 tester strains of Salmonella typhimurium to evaluate four non-genotoxic carcinogenic agents (Coumarin, β-Myrcene, Bis(2-ethylhexyl) phthalate and trans-anethole). These chemicals were tested individually and in combination with promutagens 2-aminoanthracene (2AA) and benzo(a)pyrene (BP) in presence of metabolic activation system (S9) by plate incorporation method. Exposure to all four test chemicals revealed marked increase of revertant colonies in promutagen combined groups as compared to promutagens alone. However significantly greater fold responses were observed with 2AA combination groups (Coumarin +2AA, β-Myrcene +2AA, Bis(2-ethylhexyl) phthalate +2AA and trans-anethole +2AA) with TA98 strain as compared with TA1537, which seems to have enhanced the mutagenic response of 2AA in metabolically activated conditions. It is concluded that out of both tester strains TA98 strain of Salmonella typhimurium has the potential to detect non-genotoxic carcinogens when combined with potent promutgens either by inhibiting or modulating activities of liver microsomal enzymes biochemically which may indirectly contribute to neoplastic alterations. Further this simple, short-term alternative assay may provide rapid information during extrapolative toxicology for differentiating genotoxic and non-genotoxic carcinogens.

Intestinal inflammation induces genotoxicity to extraintestinal tissues and cell types in mice

PubMed Central

Westbrook, Aya M.; Wei, Bo; Braun, Jonathan; Schiestl, Robert H.

2011-01-01

Chronic intestinal inflammation leads to increased risk of colorectal and small intestinal cancers, and is also associated with extraintestinal manifestations such as lymphomas, other solid cancers, and autoimmune disorders. We have previously found that acute and chronic intestinal inflammation causes DNA damage to circulating peripheral leukocytes, manifesting a systemic effect in genetic and chemically-induced models of intestinal inflammation. This study addresses the scope of tissue targets and genotoxic damage induced by inflammation-associated genotoxicity. Using several experimental models of intestinal inflammation, we analyzed various types of DNA damage in leukocyte subpopulations of the blood, spleen, mesenteric and peripheral lymph nodes; and, in intestinal epithelial cells, hepatocytes, and the brain. Genotoxicity in the form of DNA single and double stranded breaks accompanied by oxidative base damage was found in leukocyte subpopulations of the blood, diverse lymphoid organs, intestinal epithelial cells, and hepatocytes. The brain did not demonstrate significant levels of DNA double strand breaks as measured by γ-H2AX immunostaining. CD4+ and CD8+ T-cells were most sensitive to DNA damage versus other cell types in the peripheral blood. In vivo measurements and in vitro modeling suggested that genotoxicity was induced by increased levels of systemically circulating proinflammatory cytokines. Moreover, genotoxicity involved increased damage rather than reduced repair, since it not associated with decreased expression of the DNA double-strand break recognition and repair protein, ataxia telangiectasia mutated (ATM). These findings suggest that levels of intestinal inflammation contribute to the remote tissue burden of genotoxicity, with potential effects on non-intestinal diseases and cancer. PMID:21520038

Analysis of Aloe vera cytotoxicity and genotoxicity associated with endodontic medication and laser photobiomodulation.

PubMed

Carvalho, Nayane Chagas; Guedes, Simone Alves Garcez; Albuquerque-Júnior, Ricardo Luiz Cavalcanti; de Albuquerque, Diana Santana; de Souza Araújo, Adriano Antunes; Paranhos, Luiz Renato; Camargo, Samira Esteves Afonso; Ribeiro, Maria Amália Gonzaga

2018-01-01

This study aims to evaluate, in vitro, the effect of Aloe vera associated with endodontic medication, with or without laser photobiomodulation (FTL) irradiation in FP6 human pulp fibroblasts. The materials were divided into eight groups: CTR - control; CL - FTL alone; AA - Aloe vera with distilled water; AL - Aloe vera with distilled water and FTL; HA - calcium hydroxide P.A. with distilled water; HL - calcium hydroxide P.A. with distilled water and FTL; HAA - calcium hydroxide P.A. with Aloe vera and distilled water; HAL - calcium hydroxide P.A. with Aloe vera, distilled water, and FTL. The cytotoxicity was evaluated by MTT assay at 24, 48, and 72h and the genotoxicity by micronucleus test assay. This study was performed in triplicate. Data obtained in both tests were statistically analyzed by ANOVA and Tukey's tests (p≤0.05). Group AA presented high genotoxicity and low cytotoxicity. After 24, 48, and 72h, the group HAA significantly reduced the cell viability. Interaction with FTL showed slightly increase cell viability after 24 and 48h in groups CL and HL (p<0.001), despite the high genotoxicity in group CL and low genotoxicity in group HL. Group AL showed higher cell survival rate at 72h (p<0.05) and high genotoxicity (p<0.001). It was concluded that Aloe vera allowed higher cell viability in human pulp fibroblasts in the presence of calcium hydroxide or with FTL separately, but genotoxicity increased in these associations. Copyright © 2017 Elsevier B.V. All rights reserved.

Use of a standardized JaCVAM in vivo rat comet assay protocol to assess the genotoxicity of three coded test compounds; ampicillin trihydrate, 1,2-dimethylhydrazine dihydrochloride, and N-nitrosodimethylamine.

PubMed

McNamee, J P; Bellier, P V

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the in vivo rat alkaline comet assay (comet assay), our laboratory examined ampicillin trihydrate (AMP), 1,2-dimethylhydrazine dihydrochloride (DMH), and N-nitrosodimethylamine (NDA) using a standard comet assay validation protocol (v14.2) developed by the JaCVAM validation management team (VMT). Coded samples were received by our laboratory along with basic MSDS information. Solubility analysis and range-finding experiments of the coded test compounds were conducted for dose selection. Animal dosing schedules, the comet assay processing and analysis, and statistical analysis were conducted in accordance with the standard protocol. Based upon our blinded evaluation, AMP was not found to exhibit evidence of genotoxicity in either the rat liver or stomach. However, both NDA and DMH were observed to cause a significant increase in % tail DNA in the rat liver at all dose levels tested. While acute hepatoxicity was observed for these compounds in the high dose group, in the investigators opinion there were a sufficient number of consistently damaged/measurable cells at the medium and low dose groups to judge these compounds as genotoxic. There was no evidence of genotoxicity from either NDA or DMH in the rat stomach. In conclusion, our laboratory observed increased DNA damage from two blinded test compounds in rat liver (later identified as genotoxic carcinogens), while no evidence of genotoxicity was observed for the third blinded test compound (later identified as a non-genotoxic, non-carcinogen). This data supports the use of a standardized protocol of the in vivo comet assay as a cost-effective alternative genotoxicity assay for regulatory testing purposes. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Genotoxicity and antigenotoxicity study of aqueous and hydro-methanol extracts of Spondias mombin L., Nymphaea lotus L. and Luffa cylindrical L. using animal bioassays

PubMed Central

Oyeyemi, Ifeoluwa Temitayo; Yekeen, Olaide Maruf; Odusina, Paul Olayinka; Ologun, Taiwo Mary; Ogbaide, Orezimena Michelle; Olaleye, Olayinka Israel

2015-01-01

Spondias mombin (Linn), Nymphaea lotus (Linn) and Luffa cylindrica (Linn) (syn Luffa aegyptiaca Mill) are plants traditionally used as food ingredients and in the management of diseases, including cancer, in Nigeria. Despite the therapeutic potentials attributed to these plants, reports on their genotoxicity are scanty. In this study, the genotoxicity of the aqueous and hydro-methanol extract of these plants was evaluated using mouse bone marrow micronucleus and sperm morphology assays. Antigenotoxicity was assessed by the bone marrow micronucleus test. The highest attainable dose of 5 000 mg/kg according to OECD guidelines was first used to assess acute toxicity of the aqueous and hydro-methanol extracts in Swiss albino mice. For each extract, there were five groups of mice (n=4/group) treated with different concentrations of the extract as against the negative and positive control group for the genotoxicity study. In the antigenotoxicity study, five groups of mice were exposed to five different concentrations of the extracts along with 60 mg/kg of methyl methane sulfonate (MMS), which was used to induce genotoxicity. The mice were administered 0.2 mL of extract per day for 10 days in the genotoxicity and antigenotoxicity groups. Administration of each of the extracts at the concentration of 5 000 mg/kg did not induce acute toxicity in mice. At the concentrations tested, all the extracts, except aqueous S. mombin, increased micronucleated polychromatic erythrocytes. The aqueous and hydro-methanol extracts of N. lotus increased the frequency of aberrant sperm cells. All the extracts were also able to ameliorate MMS induced genotoxicity in bone marrow cells of the exposed mice. The results showed the potential of the extracts to induce somatic and germ cell mutation in male mice. The extracts also ameliorated the genotoxic effect of MMS. PMID:27486380

Trivalent chromium: assessing the genotoxic risk of an essential trace element and widely used human and animal nutritional supplement.

PubMed

Eastmond, David A; Macgregor, James T; Slesinski, Ronald S

2008-01-01

Trivalent chromium [Cr(III)] is recognized as an essential nutrient, and is widely used as a nutritional supplement for humans and animals. Recent reports of the induction of genetic damage in cultured cells exposed to Cr(III) compounds in vitro have heightened the concern that Cr(III) compounds may exert genotoxic effects under certain conditions, raising the question of the relative benefit versus risk of dietary and feed supplementation practices. We have reviewed the literature since 1990 on genotoxic effects of Cr(III) compounds to determine whether recent findings provide a sufficient weight of evidence to modify the conclusions about the safety of this dietary supplement reached in the several comprehensive reviews conducted during the period 1990-2004. The extensive literature on genotoxic effects of Cr(III) compounds includes many instances of conflicting information, with both negative and positive findings often reported in similar test systems. Outcomes of in vitro tests conducted with Cr(III) in cultured cells are quite variable regardless of the chemical form of the chromium compound tested. The in vitro data show that Cr(III) has the potential to react with DNA and to cause DNA damage in cell culture systems, but under normal circumstances, restricted access of Cr(III) to cells in vivo limits or prevents genotoxicity in biological systems. The available in vivo evidence suggests that genotoxic effects are very unlikely to occur in humans or animals exposed to nutritional or to moderate recommended supplemental levels of Cr(III). However, excessive intake of Cr(III) supplements does not appear to be warranted at this time. Thus, like other nutrients that have exhibited genotoxic effects in vitro under high exposure conditions, nutritional benefits appear to outweigh the theoretical risk of genotoxic effects in vivo at normal or modestly elevated physiological intake levels.

Genotoxicity and antigenotoxicity study of aqueous and hydro-methanol extracts of Spondias mombin L., Nymphaea lotus L. and Luffa cylindrical L. using animal bioassays.

PubMed

Oyeyemi, Ifeoluwa Temitayo; Yekeen, Olaide Maruf; Odusina, Paul Olayinka; Ologun, Taiwo Mary; Ogbaide, Orezimena Michelle; Olaleye, Olayinka Israel; Bakare, Adekunle A

2015-12-01

Spondias mombin (Linn), Nymphaea lotus (Linn) and Luffa cylindrica (Linn) (syn Luffa aegyptiaca Mill) are plants traditionally used as food ingredients and in the management of diseases, including cancer, in Nigeria. Despite the therapeutic potentials attributed to these plants, reports on their genotoxicity are scanty. In this study, the genotoxicity of the aqueous and hydro-methanol extract of these plants was evaluated using mouse bone marrow micronucleus and sperm morphology assays. Antigenotoxicity was assessed by the bone marrow micronucleus test. The highest attainable dose of 5 000 mg/kg according to OECD guidelines was first used to assess acute toxicity of the aqueous and hydro-methanol extracts in Swiss albino mice. For each extract, there were five groups of mice (n=4/group) treated with different concentrations of the extract as against the negative and positive control group for the genotoxicity study. In the antigenotoxicity study, five groups of mice were exposed to five different concentrations of the extracts along with 60 mg/kg of methyl methane sulfonate (MMS), which was used to induce genotoxicity. The mice were administered 0.2 mL of extract per day for 10 days in the genotoxicity and antigenotoxicity groups. Administration of each of the extracts at the concentration of 5 000 mg/kg did not induce acute toxicity in mice. At the concentrations tested, all the extracts, except aqueous S. mombin, increased micronucleated polychromatic erythrocytes. The aqueous and hydro-methanol extracts of N. lotus increased the frequency of aberrant sperm cells. All the extracts were also able to ameliorate MMS induced genotoxicity in bone marrow cells of the exposed mice. The results showed the potential of the extracts to induce somatic and germ cell mutation in male mice. The extracts also ameliorated the genotoxic effect of MMS.

Comparative cytotoxic and genotoxic potential of 13 drinking water disinfection by-products using a microplate-based cytotoxicity assay and a developed SOS/umu assay.

PubMed

Zhang, Shao-Hui; Miao, Dong-Yue; Tan, Li; Liu, Ai-Lin; Lu, Wen-Qing

2016-01-01

The implications of disinfection by-products (DBPs) present in drinking water are of public health concern because of their potential mutagenic, carcinogenic and other toxic effects on humans. In this study, we selected 13 main DBPs found in drinking water to quantitatively analyse their cytotoxicity and genotoxicity using a microplate-based cytotoxicity assay and a developed SOS/umu assay in Salmonella typhimurium TA1535/pSK1002. With the developed SOS/umu test, eight DBPs: 3-chloro-4-(dichloromethyl)-5-hydroxy-2[5H]-fura3-chloro-4-(dichloromethyl)-5-hydroxy-2-[5H]-furanone (MX), dibromoacetonitrile (DBN), iodoacetic acid (IA), bromochloroacetonitrile (BCN), bromoacetic acid (BA), trichloroacetonitrile (TCN), dibromoacetic acid (DBA) and dichloroacetic acid (DCA) were significantly genotoxic to S. typhimurium. Three DBPs: chloroacetic acid (CA), trichloroacetic acid (TCA) and dichloroacetonitrile (DCN) were weakly genotoxic, whereas the remaining DBPs: chloroacetonitrile (CN) and chloral hydrate (CH) were negative. The rank order in decreasing genotoxicity was as follows: MX > DBN > IA > BCN > BA > TCN > DBA > DCA > CA, TCA, DCN > CN, CH. MX was approximately 370 000 times more genotoxic than DCA. In the microplate-based cytotoxicity assay, cytotoxic potencies of the 13 DBPs were compared and ranked in decreasing order as follows: MX > IA > DBN > BCN > BA > TCN > DCN > CA > DCA > DBA > CN > TCA > CH. MX was approximately 19 200 times more cytotoxic than CH. A statistically significant correlation was found between cytotoxicity and genotoxicity of the 13 DBPs in S. typhimurium. Results suggest that microplate-based cytotoxicity assay and the developed SOS/umu assay are feasible tools for analysing the cytotoxicity and genotoxicity of DBPs, particularly for comparing their toxic intensities quantitatively. © The Author 2015. Published by Oxford University Press on behalf of the UK Environmental Mutagen Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Induced Jasmonate Signaling Leads to Contrasting Effects on Root Damage and Herbivore Performance1

PubMed Central

Lu, Jing; Robert, Christelle Aurélie Maud; Riemann, Michael; Cosme, Marco; Mène-Saffrané, Laurent; Massana, Josep; Stout, Michael Joseph; Lou, Yonggen; Gershenzon, Jonathan; Erb, Matthias

2015-01-01

Induced defenses play a key role in plant resistance against leaf feeders. However, very little is known about the signals that are involved in defending plants against root feeders and how they are influenced by abiotic factors. We investigated these aspects for the interaction between rice (Oryza sativa) and two root-feeding insects: the generalist cucumber beetle (Diabrotica balteata) and the more specialized rice water weevil (Lissorhoptrus oryzophilus). Rice plants responded to root attack by increasing the production of jasmonic acid (JA) and abscisic acid, whereas in contrast to in herbivore-attacked leaves, salicylic acid and ethylene levels remained unchanged. The JA response was decoupled from flooding and remained constant over different soil moisture levels. Exogenous application of methyl JA to the roots markedly decreased the performance of both root herbivores, whereas abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid did not have any effect. JA-deficient antisense 13-lipoxygenase (asLOX) and mutant allene oxide cyclase hebiba plants lost more root biomass under attack from both root herbivores. Surprisingly, herbivore weight gain was decreased markedly in asLOX but not hebiba mutant plants, despite the higher root biomass removal. This effect was correlated with a herbivore-induced reduction of sucrose pools in asLOX roots. Taken together, our experiments show that jasmonates are induced signals that protect rice roots from herbivores under varying abiotic conditions and that boosting jasmonate responses can strongly enhance rice resistance against root pests. Furthermore, we show that a rice 13-lipoxygenase regulates root primary metabolites and specifically improves root herbivore growth. PMID:25627217

Paracelsus to parascience: the environmental cancer distraction.

PubMed

Ames, B N; Gold, L S

2000-01-17

Entering a new millennium seems a good time to challenge some old ideas, which in our view are implausible, have little supportive evidence, and might best be left behind. In this essay, we summarize a decade of work, raising four issues that involve toxicology, nutrition, public health, and government regulatory policy. (a) Paracelsus or parascience: the dose (trace) makes the poison. Half of all chemicals, whether natural or synthetic, are positive in high-dose rodent cancer tests. These results are unlikely to be relevant at the low doses of human exposure. (b) Even Rachel Carson was made of chemicals: natural vs. synthetic chemicals. Human exposure to naturally occurring rodent carcinogens is ubiquitous, and dwarfs the general public's exposure to synthetic rodent carcinogens. (c) Errors of omission: micronutrient inadequacy is genotoxic. The major causes of cancer (other than smoking) do not involve exogenous carcinogenic chemicals: dietary imbalances, hormonal factors, infection and inflammation, and genetic factors. Insufficiency of many micronutrients, which appears to mimic radiation, is a preventable source of DNA damage. (d) Damage by distraction: regulating low hypothetical risks. Putting huge amounts of money into minuscule hypothetical risks damages public health by diverting resources and distracting the public from major risks.

Aldehyde Dehydrogenase 2 in Aplastic Anemia, Fanconi Anemia and Hematopoietic Stem Cells

PubMed Central

Van Wassenhove, Lauren D.; Mochly-Rosen, Daria; Weinberg, Kenneth I.

2016-01-01

Maintenance of the hematopoietic stem cell (HSC) compartment depends on the ability to metabolize exogenously and endogenously generated toxins, and to repair cellular damage caused by such toxins. Reactive aldehydes have been demonstrated to cause specific genotoxic injury, namely DNA interstrand cross-links. Aldehyde dehydrogenase 2 (ALDH2) is a member of a 19 isoenzyme ALDH family with different substrate specificities, subcellular localization, and patterns of expression. ALDH2 is localized in mitochondria and is essential for the metabolism of acetaldehyde, thereby placing it directly downstream of ethanol metabolism. Deficiency in ALDH2 expression and function are caused by a single nucleotide substitution and resulting amino acid change, called ALDH2*2. This genetic polymorphism affects 35–45% of East Asians (about ~560 million people), and causes the well-known Asian flushing syndrome, which results in disulfiram-like reactions after ethanol consumption. Recently, the ALDH2*2 genotype has been found to be associated with marrow failure, with both an increased risk of sporadic aplastic anemia and more rapid progression of Fanconi Anemia. This review discusses the unexpected interrelationship between aldehydes, ALDH2 and hematopoietic stem cell biology, and in particular its relationship to Fanconi anemia. PMID:27650066

The Mitochondrial DNA-Associated Protein SWIB5 Influences mtDNA Architecture and Homologous Recombination.

PubMed

Blomme, Jonas; Van Aken, Olivier; Van Leene, Jelle; Jégu, Teddy; De Rycke, Riet; De Bruyne, Michiel; Vercruysse, Jasmien; Nolf, Jonah; Van Daele, Twiggy; De Milde, Liesbeth; Vermeersch, Mattias; des Francs-Small, Catherine Colas; De Jaeger, Geert; Benhamed, Moussa; Millar, A Harvey; Inzé, Dirk; Gonzalez, Nathalie

2017-05-01

In addition to the nucleus, mitochondria and chloroplasts in plant cells also contain genomes. Efficient DNA repair pathways are crucial in these organelles to fix damage resulting from endogenous and exogenous factors. Plant organellar genomes are complex compared with their animal counterparts, and although several plant-specific mediators of organelle DNA repair have been reported, many regulators remain to be identified. Here, we show that a mitochondrial SWI/SNF (nucleosome remodeling) complex B protein, SWIB5, is capable of associating with mitochondrial DNA (mtDNA) in Arabidopsis thaliana Gain- and loss-of-function mutants provided evidence for a role of SWIB5 in influencing mtDNA architecture and homologous recombination at specific intermediate-sized repeats both under normal and genotoxic conditions. SWIB5 interacts with other mitochondrial SWIB proteins. Gene expression and mutant phenotypic analysis of SWIB5 and SWIB family members suggests a link between organellar genome maintenance and cell proliferation. Taken together, our work presents a protein family that influences mtDNA architecture and homologous recombination in plants and suggests a link between organelle functioning and plant development. © 2017 American Society of Plant Biologists. All rights reserved.

Protection against neo-formed contaminants (NFCs)-induced toxicity by phytochemicals.

PubMed

Zhao, Mengyao; Wang, Pengpu; Li, Daotong; Shang, Jin; Hu, Xiaosong; Chen, Fang

2017-10-01

Neo-formed compounds (NFCs) are commonly found in all kinds of foods due to the complex reaction between components during processing. Acrylamide, benzo(a)pyrene and heterocyclic aromatic amines are the main types of NFCs in foods enriched with carbohydrate, fats and proteins, respectively. They have exhibited diverse toxicity, such as neurotoxicity, genotoxicity, potentially carcinogenic and reproductive toxicity. In recent years, various phytochemicals have been found to be effective in alleviation of their related toxicities both in vitro and in vivo. This review provides evidences on the protection roles of phytochemicals against the diverse toxicity induced by three NFCs. Moreover, the prevention mechanisms of phytochemicals are summarized. Three potential aspects involving excellent antioxidant activity, DNA protection and enzyme induction contribute to the successful protection mechanism. Meanwhile, the limitations from existing knowledge have been illustrated and the possible perspectives for the further study have also been considered. The information from this review would be useful to provide an easier and better way to improve human health when considering the possibility of using foods enriched with phytochemicals for prevention of the toxicity of exogenous pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

The micronucleus test-most widely used in vivo genotoxicity test.

PubMed

Hayashi, Makoto

2016-01-01

Genotoxicity is commonly evaluated during the chemical safety assessment together with other toxicological endpoints. The micronucleus test is always included in many genotoxic test guidelines for long time in many classes of chemicals, e.g., pharmaceutical chemicals, agricultural chemicals, food additives. Although the trend of the safety assessment of chemicals faces to animal welfare and in vitro systems are more welcome than the in vivo systems, the in vivo test systems are paid more attention in the field of genotoxicity because of its weight of evidence. In this review, I will summarize the following points: 1) historical consideration of the test development, 2) characteristics of the test including advantages and limitations, 3) new approaches considering to the animal welfare.

Genotoxic effects and oxidative stress induced by organic extracts of particulate matter(PM 10)collected from a subway tunnel in Seoul, Korea.

PubMed

Jung, Mi Hyun; Kim, Ha Ryong; Park, Yong Joo; Park, Duck Shin; Chung, Kyu Hyuck; Oh, Seung Min

2012-12-12

Particulate matter (PM) has become an important health risk factor in our society. PM can easily deposit in the bronchi and lungs, causing diverse diseases such as respiratory infections, lung cancers and cardiovascular diseases. In recent days, more and more toxicological studies have been dealing with air particles in distinctive areas including industrial areas, transportation sites, or indoors. Studies on subway PM in particular, have been recognizing PM as an important health risk factor because many people use subways as a major mode of public transportation (4 million people a day in Korea). The main aim of the present study was to evaluate the genotoxic effects of organic extract (OE) of subway PM10 and potential attribution of PAHs to these effects. Particles were collected in the subway tunnel at Kil-eum station(Line 4) for one month and then extracted with Dichloromethane (DCM). Chinese Hamster Ovary cells(CHO-K1) and human normal bronchial cells (BEAS-2B) were exposed to OE, and MN and Comet assays were conducted to analyze the genotoxicity. The results showed that OE increased DNA or chromosome damages in both cell lines. In the modified Comet assay and MN assay with free radical scavengers, we confirmed that the genotoxic effect of OE was partially due to the oxidative damage on DNA. DCFHD Aassay also indicated that OE induced ROS generation in BEAS-2B cells. PAHs [benzo(a)anthracene,benzo(k)fluoranthrene, etc.], the most well-known carcinogens in polluted air, were detected in Kil-eum PM10. In conclusion, our findings confirmed that OE of subway PM10 has genotoxic effects on normal human lung cells, and oxidative stress could be one of the major mechanisms of these genotoxic effects.In addition, some genotoxic and carcinogenic PAHs were detected in OE by GC/MS/MS, even though PAHs level was not enough to increase CYP1A1 gene. Therefore, we suggest that additive or synergistic effects by unidentified chemicals as well as PAHs contained in OE of subway PM10 may induce genotoxic effects and further researches are needed to identify the genotoxic compounds in subway PM.

Role of Bacillus subtilis Error Prevention Oxidized Guanine System in Counteracting Hexavalent Chromium-Promoted Oxidative DNA Damage

PubMed Central

Santos-Escobar, Fernando; Gutiérrez-Corona, J. Félix

2014-01-01

Chromium pollution is potentially detrimental to bacterial soil communities, compromising carbon and nitrogen cycles that are essential for life on earth. It has been proposed that intracellular reduction of hexavalent chromium [Cr(VI)] to trivalent chromium [Cr(III)] may cause bacterial death by a mechanism that involves reactive oxygen species (ROS)-induced DNA damage; the molecular basis of the phenomenon was investigated in this work. Here, we report that Bacillus subtilis cells lacking a functional error prevention oxidized guanine (GO) system were significantly more sensitive to Cr(VI) treatment than cells of the wild-type (WT) strain, suggesting that oxidative damage to DNA is involved in the deleterious effects of the oxyanion. In agreement with this suggestion, Cr(VI) dramatically increased the ROS concentration and induced mutagenesis in a GO-deficient B. subtilis strain. Alkaline gel electrophoresis (AGE) analysis of chromosomal DNA of WT and ΔGO mutant strains subjected to Cr(VI) treatment revealed that the DNA of the ΔGO strain was more susceptible to DNA glycosylase Fpg attack, suggesting that chromium genotoxicity is associated with 7,8-dihydro-8-oxodeoxyguanosine (8-oxo-G) lesions. In support of this notion, specific monoclonal antibodies detected the accumulation of 8-oxo-G lesions in the chromosomes of B. subtilis cells subjected to Cr(VI) treatment. We conclude that Cr(VI) promotes mutagenesis and cell death in B. subtilis by a mechanism that involves radical oxygen attack of DNA, generating 8-oxo-G, and that such effects are counteracted by the prevention and repair GO system. PMID:24973075

TRAF Family Member-associated NF-κB Activator (TANK) Inhibits Genotoxic Nuclear Factor κB Activation by Facilitating Deubiquitinase USP10-dependent Deubiquitination of TRAF6 Ligase*

PubMed Central

Wang, Wei; Huang, Xuan; Xin, Hong-Bo; Fu, Mingui; Xue, Aimin; Wu, Zhao-Hui

2015-01-01

DNA damage-induced NF-κB activation plays a critical role in regulating cellular response to genotoxic stress. However, the molecular mechanisms controlling the magnitude and duration of this genotoxic NF-κB signaling cascade are poorly understood. We recently demonstrated that genotoxic NF-κB activation is regulated by reversible ubiquitination of several essential mediators involved in this signaling pathway. Here we show that TRAF family member-associated NF-κB activator (TANK) negatively regulates NF-κB activation by DNA damage via inhibiting ubiquitination of TRAF6. Despite the lack of a deubiquitination enzyme domain, TANK has been shown to negatively regulate the ubiquitination of TRAF proteins. We found TANK formed a complex with MCPIP1 (also known as ZC3H12A) and a deubiquitinase, USP10, which was essential for the USP10-dependent deubiquitination of TRAF6 and the resolution of genotoxic NF-κB activation upon DNA damage. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated deletion of TANK in human cells significantly enhanced NF-κB activation by genotoxic treatment, resulting in enhanced cell survival and increased inflammatory cytokine production. Furthermore, we found that the TANK-MCPIP1-USP10 complex also decreased TRAF6 ubiquitination in cells treated with IL-1β or LPS. In accordance, depletion of USP10 enhanced NF-κB activation induced by IL-1β or LPS. Collectively, our data demonstrate that TANK serves as an important negative regulator of NF-κB signaling cascades induced by genotoxic stress and IL-1R/Toll-like receptor stimulation in a manner dependent on MCPIP1/USP10-mediated TRAF6 deubiquitination. PMID:25861989

The use of dose-response data in a margin of exposure approach to carcinogenic risk assessment for genotoxic chemicals in food.

PubMed

Benford, Diane J

2016-05-01

Genotoxic substances are generally not permitted for deliberate use in food production. However, an appreciable number of known or suspected genotoxic substances occur unavoidably in food, e.g. from natural occurrence, environmental contamination and generation during cooking and processing. Over the past decade a margin of exposure (MOE) approach has increasingly been used in assessing the exposure to substances in food that are genotoxic and carcinogenic. The MOE is defined as a reference point on the dose-response curve (e.g. a benchmark dose lower confidences limit derived from a rodent carcinogenicity study) divided by the estimated human intake. A small MOE indicates a higher concern than a very large MOE. Whilst the MOE cannot be directly equated to risk, it supports prioritisation of substances for further research or for possible regulatory action, and provides a basis for communicating to the public. So far, the MOE approach has been confined to substances for which carcinogenicity data are available. In the absence of carcinogenicity data, evidence of genotoxicity is used only in hazard identification. The challenge to the genetic toxicology community is to develop approaches for characterising risk to human health based on data from genotoxicity studies. In order to achieve wide acceptance, it would be important to further address the issues that have been discussed in the context of dose-response modelling of carcinogenicity data in order to assign levels of concern to particular MOE values, and also whether it is possible to make generic conclusions on how potency in genotoxicity assays relates to carcinogenic potency. © Crown copyright 2015.

Monitoring hospital wastewaters for their probable genotoxicity and mutagenicity.

PubMed

Sharma, Pratibha; Mathur, N; Singh, A; Sogani, M; Bhatnagar, P; Atri, R; Pareek, S

2015-01-01

Cancer is a leading cause of death worldwide. Excluding the genetic factors, environmental factors, mainly the pollutants, have been implicated in the causation of the majority of cancers. Wastewater originated from health-care sectors such as hospitals may carry vast amounts of carcinogenic and genotoxic chemicals to surface waters or any other source of drinking water, if discharged untreated. Humans get exposed to such contaminants through a variety of ways including drinking water. The aim of the present study was, thus, to monitor the genotoxic and mutagenic potential of wastewaters from three big hospitals located in Jaipur (Rajasthan), India. One of them was operating an effluent treatment plant (ETP) for treatment of its wastewater and therefore both the untreated and treated effluents from this hospital were studied for their genotoxicity. Two short-term bacterial bioassays namely the Salmonella fluctuation assay and the SOS chromotest were used for the purpose. Results of fluctuation assay revealed the highly genotoxic nature of all untreated effluent samples with mutagenicity ratios (MR) up to 23.13 ± 0.18 and 42.25 ± 0.35 as measured with Salmonella typhimurium strains TA98 and TA100, respectively. As determined with the chromotest, all untreated effluents produced significant induction factors (IF) ranging from 3.29 ± 1.11 to 13.35 ± 3.58 at higher concentrations. In contrast, treated effluent samples were found to be slightly genotoxic in fluctuation test only with an MR = 3.75 ± 0.35 for TA100 at 10 % concentration. Overall, the results indicated that proper treatment of hospital wastewaters may render the effluents safe for disposal contrary to the untreated ones, possessing high genotoxic potential.

Prediction model of potential hepatocarcinogenicity of rat hepatocarcinogens using a large-scale toxicogenomics database

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uehara, Takeki, E-mail: takeki.uehara@shionogi.co.jp; Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085; Minowa, Yohsuke

2011-09-15

The present study was performed to develop a robust gene-based prediction model for early assessment of potential hepatocarcinogenicity of chemicals in rats by using our toxicogenomics database, TG-GATEs (Genomics-Assisted Toxicity Evaluation System developed by the Toxicogenomics Project in Japan). The positive training set consisted of high- or middle-dose groups that received 6 different non-genotoxic hepatocarcinogens during a 28-day period. The negative training set consisted of high- or middle-dose groups of 54 non-carcinogens. Support vector machine combined with wrapper-type gene selection algorithms was used for modeling. Consequently, our best classifier yielded prediction accuracies for hepatocarcinogenicity of 99% sensitivity and 97% specificitymore » in the training data set, and false positive prediction was almost completely eliminated. Pathway analysis of feature genes revealed that the mitogen-activated protein kinase p38- and phosphatidylinositol-3-kinase-centered interactome and the v-myc myelocytomatosis viral oncogene homolog-centered interactome were the 2 most significant networks. The usefulness and robustness of our predictor were further confirmed in an independent validation data set obtained from the public database. Interestingly, similar positive predictions were obtained in several genotoxic hepatocarcinogens as well as non-genotoxic hepatocarcinogens. These results indicate that the expression profiles of our newly selected candidate biomarker genes might be common characteristics in the early stage of carcinogenesis for both genotoxic and non-genotoxic carcinogens in the rat liver. Our toxicogenomic model might be useful for the prospective screening of hepatocarcinogenicity of compounds and prioritization of compounds for carcinogenicity testing. - Highlights: >We developed a toxicogenomic model to predict hepatocarcinogenicity of chemicals. >The optimized model consisting of 9 probes had 99% sensitivity and 97% specificity. >This model enables us to detect genotoxic as well as non-genotoxic hepatocarcinogens.« less

Environmental stress in the Gulf of Mexico and its potential impact on public health

PubMed Central

Turner, J.; Walter, L.; Lathan, N.; Thorpe, D.; Ogbevoen, P.; Daye, J.; Alcorn, D.; Wilson, S.; Semien, J.; Richard, T.; Johnson, T.; McCabe, K.; Estrada, J.J.; Galvez, F.; Velasco, C.; Reiss, K.

2017-01-01

The Deepwater Horizon (DWH) oil spill in the Gulf of Mexico was the largest maritime oil spill in history resulting in the accumulation of genotoxic substances in the air, soil, and water. This has potential far-reaching health impacts on cleanup field workers and on the populations living in the contaminated coastal areas. We have employed portable airborne particulate matter samplers (SKC Biosampler Impinger) and a genetically engineered bacterial reporter system (umu-ChromoTest from EBPI) to determine levels of genotoxicity of air samples collected from highly contaminated areas of coastal Louisiana including Grand Isle, Port Fourchon, and Elmer's Island in the spring, summer and fall of 2011, 2012, 2013 and 2014. Air samples collected from a non-contaminated area, Sea Rim State Park, Texas, served as a control for background airborne genotoxic particles. In comparison to controls, air samples from the contaminated areas demonstrated highly significant increases in genotoxicity with the highest values registered during the month of July in 2011, 2013, and 2014, in all three locations. This seasonal trend was disrupted in 2012, when the highest genotoxicity values were detected in October, which correlated with hurricane Isaac landfall in late August of 2012, about five weeks before a routine collection of fall air samples. Our data demonstrate: (i) high levels of air genotoxicity in the monitored areas over last four years post DWH oil spill; (ii) airborne particulate genotoxicity peaks in summers and correlates with high temperatures and high humidity; and (iii) this seasonal trend was disrupted by the hurricane Isaac landfall, which further supports the concept of a continuous negative impact of the oil spill in this region. PMID:26745734

Environmental stress in the Gulf of Mexico and its potential impact on public health.

PubMed

Singleton, B; Turner, J; Walter, L; Lathan, N; Thorpe, D; Ogbevoen, P; Daye, J; Alcorn, D; Wilson, S; Semien, J; Richard, T; Johnson, T; McCabe, K; Estrada, J J; Galvez, F; Velasco, C; Reiss, K

2016-04-01

The Deepwater Horizon (DWH) oil spill in the Gulf of Mexico was the largest maritime oil spill in history resulting in the accumulation of genotoxic substances in the air, soil, and water. This has potential far-reaching health impacts on cleanup field workers and on the populations living in the contaminated coastal areas. We have employed portable airborne particulate matter samplers (SKC Biosampler Impinger) and a genetically engineered bacterial reporter system (umu-ChromoTest from EBPI) to determine levels of genotoxicity of air samples collected from highly contaminated areas of coastal Louisiana including Grand Isle, Port Fourchon, and Elmer's Island in the spring, summer and fall of 2011, 2012, 2013 and 2014. Air samples collected from a non-contaminated area, Sea Rim State Park, Texas, served as a control for background airborne genotoxic particles. In comparison to controls, air samples from the contaminated areas demonstrated highly significant increases in genotoxicity with the highest values registered during the month of July in 2011, 2013, and 2014, in all three locations. This seasonal trend was disrupted in 2012, when the highest genotoxicity values were detected in October, which correlated with hurricane Isaac landfall in late August of 2012, about five weeks before a routine collection of fall air samples. Our data demonstrate: (i) high levels of air genotoxicity in the monitored areas over last four years post DWH oil spill; (ii) airborne particulate genotoxicity peaks in summers and correlates with high temperatures and high humidity; and (iii) this seasonal trend was disrupted by the hurricane Isaac landfall, which further supports the concept of a continuous negative impact of the oil spill in this region. Copyright © 2015 Elsevier Inc. All rights reserved.

A novel genotoxin-specific qPCR array based on the metabolically competent human HepaRG™ cell line as a rapid and reliable tool for improved in vitro hazard assessment.

PubMed

Ates, Gamze; Mertens, Birgit; Heymans, Anja; Verschaeve, Luc; Milushev, Dimiter; Vanparys, Philippe; Roosens, Nancy H C; De Keersmaecker, Sigrid C J; Rogiers, Vera; Doktorova, Tatyana Y

2018-04-01

Although the value of the regulatory accepted batteries for in vitro genotoxicity testing is recognized, they result in a high number of false positives. This has a major impact on society and industries developing novel compounds for pharmaceutical, chemical, and consumer products, as afflicted compounds have to be (prematurely) abandoned or further tested on animals. Using the metabolically competent human HepaRG ™ cell line and toxicogenomics approaches, we have developed an upgraded, innovative, and proprietary gene classifier. This gene classifier is based on transcriptomic changes induced by 12 genotoxic and 12 non-genotoxic reference compounds tested at sub-cytotoxic concentrations, i.e., IC10 concentrations as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The resulting gene classifier was translated into an easy-to-handle qPCR array that, as shown by pathway analysis, covers several different cellular processes related to genotoxicity. To further assess the predictivity of the tool, a set of 5 known positive and 5 known negative test compounds for genotoxicity was evaluated. In addition, 2 compounds with debatable genotoxicity data were tested to explore how the qPCR array would classify these. With an accuracy of 100%, when equivocal results were considered positive, the results showed that combining HepaRG ™ cells with a genotoxin-specific qPCR array can improve (geno)toxicological hazard assessment. In addition, the developed qPCR array was able to provide additional information on compounds for which so far debatable genotoxicity data are available. The results indicate that the new in vitro tool can improve human safety assessment of chemicals in general by basing predictions on mechanistic toxicogenomics information.

Genotoxicity of two heavy metal compounds: lead nitrate and cobalt chloride in Polychaete Perinereis cultrifera.

PubMed

Singh, Nisha; Bhagat, Jacky; Ingole, Baban S

2017-07-01

The present study explores the in vivo and in vitro genotoxic effects of lead nitrate, [Pb(NO 3 ) 2 ] a recognized environmental pollutant and cobalt chloride (CoCl 2 ), an emerging environmental pollutant in polychaete Perinereis cultrifera using comet assay. Despite widespread occurrence and extensive industrial applications, no previous published reports on genotoxicity of these compounds are available in polychaete as detected by comet assay. Polychaetes were exposed in vivo to Pb(NO 3 ) 2 (0, 100, 500, and 1000 μg/l) and CoCl 2 (0, 100, 300, and 500 μg/l) for 5 days. At 100 μg/l Pb(NO 3 ) 2 concentration, tail DNA (TDNA) values in coelomocytes were increase by 1.16, 1.43, and 1.55-fold after day 1, day 3, and day 5, whereas, OTM showed 1.12, 2.33, and 2.10-fold increase in in vivo. Pb(NO 3 ) 2 showed a concentration and time-dependent genotoxicity whereas CoCl 2 showed a concentration-dependent genotoxicity in in vivo. A concentration-dependent increase in DNA damage was observed in in vitro studies for Pb(NO 3 ) 2 and CoCl 2 . DNA damage at 500 μg/L showed almost threefold increase in TDNA and approximately fourfold increase in OTM as compared to control in in vitro. Our studies suggest that Pb(NO 3 ) 2 and CoCl 2 have potential to cause genotoxic damage, with Pb(NO 3 ) 2 being more genotoxic in polychaete and should be used more carefully in industrial and other activities. Graphical abstract.

Genotoxic damage in polychaetes: a study of species and cell-type sensitivities.

PubMed

Lewis, Ceri; Galloway, Tamara

2008-06-30

The marine environment is becoming increasingly contaminated by environmental pollutants with the potential to damage DNA, with marine sediments acting as a sink for many of these contaminants. Understanding genotoxic responses in sediment-dwelling marine organisms, such as polychaetes, is therefore of increasing importance. This study is an exploration of species-specific and cell-specific differences in cell sensitivities to DNA-damaging agents in polychaete worms, aimed at increasing fundamental knowledge of their responses to genotoxic damage. The sensitivities of coelomocytes from three polychaetes species of high ecological relevance, i.e. the lugworm Arenicola marina, the harbour ragworm Nereis diversicolor and the king ragworm Nereis virens to genotoxic damage are compared, and differences in sensitivities of their different coelomic cell types determined by use of the comet assay. A. marina was found to be the most sensitive to genotoxic damage induced by the direct-acting mutagen methyl methanesulfonate (MMS), and showed dose-dependent responses to MMS and the polycyclic aromatic hydrocarbon benzo(a)pyrene. Significant differences in sensitivity were also measured for the different types of coelomocyte. Eleocytes were more sensitive to induction of DNA damage than amoebocytes in both N. virens and N. diversicolor. Spermatozoa from A. marina showed significant DNA damage following in vitro exposure to MMS, but were less sensitive to DNA damage than coelomocytes. This investigation has clearly demonstrated that different cell types within the same species and different species within the polychaetes show significantly different responses to genotoxic insult. These findings are discussed in terms of the relationship between cell function and sensitivity and their implications for the use of polychaetes in environmental genotoxicity studies.

Genotoxicity testing of different types of beverages in the Drosophila wing Somatic Mutation And Recombination Test.

PubMed

Graf, U; Moraga, A A; Castro, R; Díaz Carrillo, E

1994-05-01

Five wines and one brandy of Spanish origin as well as three herbal teas and ordinary black tea were tested for genotoxicity in the wing Somatic Mutation And Recombination Test (SMART) which makes use of the two recessive wing cell markers multiple wing hairs (mwh) and flare (flr3) on the left arm of chromosome 3 of Drosophila melanogaster. 3-day-old larvae trans-heterozygous for these two markers were fed the beverages at different concentrations and for different feeding periods using Drosophila instant medium. Somatic mutations or mitotic recombinations induced in the cells of the wing imaginal discs give rise to mutant single or twin spots on the wing blade of the emerging adult flies showing either the mwh phenotype or/and the flr phenotype. One of the red wines showed a clear genotoxic activity that was not due to its ethanol content. Two herbal teas (Urtica dioica, Achillea millefolium) and black tea (Camellia sinensis) proved to be weakly genotoxic as well. Furthermore, it was shown that quercetin and rutin, two flavonols present in beverages of plant origin, also exhibited weak genotoxic activity in the somatic cells of Drosophila. These results demonstrate that Drosophila in vivo somatic assays can detect the genotoxicity of complex mixtures such as beverages. In particular, it is possible to administer these test materials in the same form as that in which they are normally consumed.

Genotoxicity evaluation of carvacrol in rats using a combined micronucleus and comet assay.

PubMed

Llana-Ruiz-Cabello, María; Maisanaba, Sara; Puerto, María; Prieto, Ana I; Pichardo, Silvia; Moyano, Rosario; González-Pérez, José A; Cameán, Ana M

2016-12-01

Genotoxic data of substances which could be incorporated into food packaging are required by the European Food Safety Authority. Due to its antioxidant and antibacterial properties carvacrol is one of these compounds. This work aims to study for the first time the in vivo genotoxic effects produced in rats orally exposed to 81, 256 or 810 mg cavacrol/kg body weight (bw) at 0, 24 and 45 h. A combination of the micronucleus assay (OECD 474) in bone marrow and the standard (OECD 489) and enzyme-modified comet assay was used to determine the genotoxicity on cells isolated from stomach and liver of exposed animals. In addition, a histopathological study was performed on the assayed tissues, and also in the lungs due to the volatility of carvacrol. Direct analytical pyrolysis was used to search for carvacrol in viscera and to ensure that the compound reaches stomach and liver cells. Results from MN-comet assay revealed that carvacrol (81-810 mg/kg bw) did not induce in vivo genotoxicity or oxidative DNA damage in any of the tissues investigated. Moreover, no histopathological changes were observed. Altogether, these results suggest lack of genotoxicity of carvacrol and therefore its good profile for its potential application as food preservative. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of antigenotoxic effects of carotenoids from green algae Chlorococcum humicola using human lymphocytes

PubMed Central

Bhagavathy, S; Sumathi, P

2012-01-01

Objective To identify the available phytochemicals and carotenoids in the selected green algae and evaluate the potential genotoxic/antigenotoxic effect using lymphocytes. Methods Organic solvent extracts of Chlorococcum humicola (C. humicola) were used for the phytochemical analysis. The available carotenoids were assessed by HPLC, and LC-MS analysis. The genotoxicity was induced by the benzo(a)pyrene in the lymphocyte culture, the genotoxic and antigenotoxic effects of algal carotenoids with and without genotoxic inducer were evaluated by chromosomal aberration (CA), sister chromatid exchange (SCE) and micronucleus assay (MN). Results The results of the analysis showed that the algae were rich in carotenoids and fatty acids. In the total carotenoids lutein, β-carotene and α-carotene were found to be present in higher concentration. The frequency of CA and SCE increased by benzo(a)pyrene were significantly decreased by the carotenoids (P<0.05 for CA, P<0.001 for SCE). The MN frequencies of the cells were significantly decreased by the treatment with carotenoids when compared with the positive controls (P<0.05). Conclusions The findings of the present study demonstrate that, the green algae C. humicola is a rich source of bioactive compounds especially carotenoids which effectively fight against environmental genotoxic agents, the carotenoids itself is not a genotoxic substance and should be further considered for its beneficial effects. PMID:23569879

Evaluation of genotoxic potential of neurotoxin anatoxin-a with the use of umuC test.

PubMed

Sieroslawska, Anna; Rymuszka, Anna

2010-01-01

The aim of this study was to evaluate genotoxicity of anatoxin-a, cyanotoxin of neurotoxic activity. Additionally, other frequently detected cyanotoxin of previously described genotoxic potential, microcystin-LR, was used at the same concentrations, as well as the mixture of both toxins, anatoxin-a and microcystin-LR. Genotoxicity of the toxins was determined with the use of the umuC assay, in which the induction and expression of the umuC - lacZ reporter gene was assessed. The test was conducted on Salmonella typhimurium TA 1535/pSK1002 strain, with and without metabolic transformation. The toxin concentrations were 0.25, 0.5, 1 and 2 µg/ml. The exposure time was 2 h. The highest inefficient concentration of anatoxin-a without metabolic transformation was 0.25 µg/ml, of microcystin-LR was 0.5 µg/ml and in case of the toxin mixture all used concentrations induced the umuC gene. When S9 fraction was added to the samples, no effects were detected. To our knowledge, this is the first report on genotoxic effects of anatoxin-a. Although the study is preliminary and needs further research, however, indicates the new potential activity of the toxin, as well as the possible increase of genotoxicity of other cyanotoxins, more stable in the environment, e.g. microcystin-LR.

Baccharis trimera (Less.) DC as genotoxicity indicator of exposure to coal and emissions from a thermal power plant.

PubMed

Menezes, Ana Paula Simões; Da Silva, Juliana; Roloff, Joice; Reyes, Juliana; Debastiani, Rafaela; Dias, Johnny F; Rohr, Paula; de Barros Falcão Ferraz, Alexandre

2013-10-01

During coal combustion, hazardous elements are discharged that impair environmental quality. Plant cover is the first available surface for the atmospheric pollutants in terrestrial ecosystems. The aim of this study was to evaluate genotoxicity in the aqueous extract of the native plant, Baccharis trimera, exposed to coal and emissions from a thermal power plant (coal-fired power plant in Candiota, Brazil), correlating seasonality, wind tunnel predominance, and presence of inorganic elements. The presence of inorganic elements in the aerial parts of B. trimera was analyzed by particle-induced X-ray emission (PIXE) spectrometry, and genotoxicity was evaluated by ex vivo comet assay. The genotoxic effects of aqueous extracts of B. trimera from four sites located in the area around power plant were analyzed by comet assay in peripheral human lymphocytes. Winter samples showed greater levels of metals than summer samples. Genotoxicity was detected in B. trimera extracts collected from the region exposed to extraction and burning coal. Extracts from the site impacted by the dominant wind induced more damage to DNA than those from other sites. Based on our data, we can suggest that in winter the inorganic elements from extraction and burning of coal and carried through the wind tunnel were responsible for the genotoxicity observed in aqueous extract of B. trimera.

Evaluation of the GADD45α-GFP GreenScreen HC assay for rapid and reliable in vitro early genotoxicity screening.

PubMed

Luzy, Anne-Pascale; Orsini, Nicolas; Linget, Jean-Michel; Bouvier, Guy

2013-11-01

Twenty-two of Galderma's proprietary compounds were tested in the GADD45α-GFP 'GreenScreen HC' assay (GS), the SOS-ChromoTest and the Mini-Ames to evaluate GSs performance for early genotoxicity screening purposes. Forty more characterized compounds were also tested, including antibiotics: metronidazole, clindamycin, tetracycline, lymecycline and neomycin; and catecholamines: resorcinol mequinol, hydroquinone, one aneugen carbendazim, one corticoid dexamethasone, one peroxisome proliferator-activated receptor rosiglitazone, one pesticide carbaryl and two further proprietary molecules with in vitro genotoxicity data. With proprietary molecules, this study concluded that the GS renders the SOS-ChromoTest obsolete for in vitro screening. The GS confirmed all results of the Mini-Ames test (100% concordance). Compared with the micronucleus test, the GS showed a concordance of 82%. With known compounds, the GS ranked the potency of positive results for catecholamines in accordance with other genotoxicity tests and showed very reproducible results. It confirmed positive results for carbendazim, for tetracycline antibiotics and for carbaryl. The GS produced negative results for metronidazole, a nitroreduction-specific bacterial mutagen, for dexamethasone (a non-genotoxic apoptosis inducer), for rosiglitazone (a GADD45γ promoter inducer) and for clindamycin and neomycin (inhibitors of macromolecular synthesis in bacteria). As such, the GS appears to be a reproducible, robust, specific and sensitive test for genotoxicity screening. Copyright © 2012 John Wiley & Sons, Ltd.

Genotoxic and chemopreventive assessment of Cynara scolymus L. aqueous extract in a human-derived liver cell line.

PubMed

da Silva, Regiane Pereira; Jacociunas, Laura Vicedo; de Carli, Raíne Fogliati; de Abreu, Bianca Regina Ribas; Lehmann, Mauricio; da Silva, Juliana; Ferraz, Alexandre de Barros Falcão; Dihl, Rafael Rodrigues

2017-10-01

Cynara scolymus L., popularly known as artichoke, is consumed as food and used as tea infusions for pharmacological purposes to treat liver dysfunctions and other conditions. Scientific data on the safety and protective effect of artichoke in human-derived liver cells is missing. This study investigated the genotoxic and modulatory effect of a liophilized extract suspended in water of C. scolymus L. leaves. Four extract concentrations (0.62, 1.25, 2.5 and 5.0 mg/mL) were evaluated using the comet assay on human hepatocyte cultures, HepG2 cells. Genotoxicity was assessed after two treatment periods, 1 and 24 h. Antigenotoxicity was evaluated against oxidative lesions induced by hydrogen peroxide in pre-, simultaneous and post-treatment protocols. Artichoke leaves aqueous extract induced genotoxic effects in HepG2 cells after 1- and 24-h treatments. In turn, extract concentrations of 0.62, 1.25 and 2.5 mg/mL, exhibited a protective effect in pretreatment, compared to hydrogen peroxide alone. However, in simultaneous and post-treatment protocols, only the lowest concentration reduced the frequency of DNA damage induced by hydrogen peroxide. In addition, in the simultaneous treatment protocol, the highest artichoke extract concentration increased hydrogen peroxide genotoxicity. It can be concluded that artichoke is genotoxic, in vitro, to HepG2 cells, but can also modulate hydrogen peroxide DNA damage.

Chemopreventive effect and lack of genotoxicity and mutagenicity of the exopolysaccharide botryosphaeran on human lymphocytes.

PubMed

Malini, M; Camargo, M S; Hernandes, L C; Vargas-Rechia, C G; Varanda, E A; Barbosa, A M; Dekker, R F H; Matsumoto, S T; Antunes, L M G; Cólus, I M S

2016-10-01

Carbohydrate biopolymers of fungal-origin are an important natural resource in the search for new bioagents with therapeutic and nutraceutical potential. In this study the mutagenic, genotoxic, antigenotoxic and antioxidant properties of the fungal exopolysaccharide botryosphaeran, a (1→3)(1→6)-β-D-glucan, from Botryosphaeria rhodina MAMB-05, was evaluated. The mutagenicity was assessed at five concentrations in Salmonella typhimurium by the Ames test. Normal and tumor (Jurkat cells) human T lymphocyte cultures were used to evaluate the genotoxicity and antigenotoxicity (Comet assay) of botryosphaeran alone and in combination with the mutagen methyl methanesulfonate (MMS). The ability of botryosphaeran to reduce the production of reactive oxygen and nitrogen species (RONS) generated by hydrogen peroxide was assessed using the CM-H2DCFDA probe in lymphocyte cultures under different treatment times. None of the evaluated botryosphaeran concentrations were mutagenic in bacteria, nor induced genotoxicity in normal and tumor lymphocytes. Botryosphaeran protected lymphocyte DNA against damage caused by MMS under simultaneous treatment and post-treatment conditions. However, botryosphaeran was not able to reduce the RONS generated by H2O2. Besides the absence of genotoxicity, botryosphaeran exerted a protective effect on human lymphocytes against genotoxic damage caused by MMS. These results are important in the validation of botryosphaeran as a therapeutic agent targeting health promotion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fruit extract of the medicinal plant Crataegus oxyacantha exerts genotoxic and mutagenic effects in cultured cells.

PubMed

de Quadros, Ana Paula Oliveira; Mazzeo, Dania Elisa Christofoletti; Marin-Morales, Maria Aparecida; Perazzo, Fábio Ferreira; Rosa, Paulo Cesar Pires; Maistro, Edson Luis

2017-01-01

Crataegus oxyacantha, a plant of the Rosaceae family also known "English hawthorn, haw, maybush, or whitethorn," has long been used for medicinal purposes such as digestive disorders, hyperlipidemia, dyspnea, inducing diuresis, and preventing kidney stones. However, the predominant use of this plant has been to treat cardiovascular disorders. Due to a lack of studies on the genotoxicity of C. oxyacantha, this investigation was undertaken to determine whether its fruit extract exerts cytotoxic, genotoxic, or clastogenic/aneugenic effects in leukocytes and HepG2 (liver hepatocellular carcinoma) cultured human cells, or mutagenic effects in TA100 and TA98 strains of Salmonella typhimurium bacterium. Genotoxicity analysis showed that the extract produced no marked genotoxic effects at concentrations of 2.5 or 5 µg/ml in either cell type; however, at concentrations of 10 µg/ml or higher significant DNA damage was detected. The micronucleus test also demonstrated that concentrations of 10 µg/ml or higher produced clastogenic/aneugenic responses. In the Ames test, the extract induced mutagenic effects in TA98 strain of S. typhimurium with metabolic activation at all tested concentrations (2.5 to 500 µg/ml). Data indicate that, under certain experimental conditions, the fruit extract of C. oxyacantha exerts genotoxic and clastogenic/aneugenic effects in cultured human cells, and with metabolism mutagenicity occurs in bacteria cells.

Role of Proteus mirabilis MR/P fimbriae and flagella in adhesion, cytotoxicity and genotoxicity induction in T24 and Vero cells.

PubMed

Scavone, Paola; Villar, Silvia; Umpiérrez, Ana; Zunino, Pablo

2015-06-01

Proteus mirabilis is frequently associated with complicated urinary tract infections (UTI). It is proposed that several virulence factors are associated with P. mirabilis uropathogenicity. The aim of this work was to elucidate genotoxic and cytotoxic effects mediated by MR/P fimbriae and flagella in eukaryotic cells in vitro. Two cell lines (kidney- and bladder-derived) were infected with a clinical wild-type P. mirabilis strain and an MR/P and a flagellar mutant. We evaluated adhesion, genotoxicity and cytotoxicity by microscopy, comet assay and triple staining technique, respectively. Mutant strains displayed lower adhesion rates than the P. mirabilis wild-type strain and were significantly less effective to induce genotoxic and cytotoxic effects compared to the wild type. We report for the first time that P. mirabilis MR/P fimbriae and flagella mediate genotoxic and cytotoxic effects on eukaryotic cells, at least in in vitro conditions. These results could contribute to design new strategies for the control of UTI. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

"Aspartame: A review of genotoxicity data".

PubMed

Kirkland, David; Gatehouse, David

2015-10-01

Aspartame is a methyl ester of a dipeptide of aspartic acid and phenylalanine. It is 200× sweeter than sucrose and is approved for use in food products in more than 90 countries around the world. Aspartame has been evaluated for genotoxic effects in microbial, cell culture and animal models, and has been subjected to a number of carcinogenicity studies. The in vitro and in vivo genotoxicity data available on aspartame are considered sufficient for a thorough evaluation. There is no evidence of induction of gene mutations in a series of bacterial mutation tests. There is some evidence of induction of chromosomal damage in vitro, but this may be an indirect consequence of cytotoxicity. The weight of evidence from in vivo bone marrow micronucleus, chromosomal aberration and Comet assays is that aspartame is not genotoxic in somatic cells in vivo. The results of germ cell assays are difficult to evaluate considering limited data available and deviations from standard protocols. The available data therefore support the conclusions of the European Food Safety Authority (EFSA) that aspartame is non-genotoxic. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Genotoxic effects of nickel, trivalent and hexavalent chromium on the Eisenia fetida earthworm.

PubMed

Bigorgne, Emilie; Cossu-Leguille, Carole; Bonnard, Marc; Nahmani, Johanne

2010-08-01

The aim of this study was to examine genotoxic effects of nickel (Ni=105 mg kg(-1)), trivalent and hexavalent chromium (Cr=491 mg kg(-1)) on the Eisenia fetida earthworm after 2 and 4d of exposure to two different spiked soils (an artificial (OECD) and a natural one). DNA damages were evaluated on the earthworm's coelomocytes using the comet assay. After an exposure into OECD spiked soils, Ni did not induce genotoxic effect whereas Cr(III) and Cr(VI) revealed to be genotoxic after 2d of exposure. After 4d of exposure, only Cr(VI) still induced significant damages. In natural spiked soils, nickel and Cr(III) revealed to be genotoxic after 2 and 4d of exposure. Concerning Cr(VI) toxicity, all the earthworms died after 1d of exposure. These results underline the importance to take into account the nature and the speciation of metallic pollutants, although the experiment has been performed on spiked soil with higher bioavailibity than in contaminated natural soil. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Comparative cytotoxicity and genotoxicity of particulate and soluble hexavalent chromium in human and sperm whale (Physeter macrocephalus) skin cells.

PubMed

Li Chen, Tânia; LaCerte, Carolyne; Wise, Sandra S; Holmes, Amie; Martino, Julieta; Wise, John Pierce; Thompson, W Douglas; Wise, John Pierce

2012-01-01

Chromium (Cr) is a global marine pollutant, present in marine mammal tissues. Hexavalent chromium [Cr(VI)] is a known human carcinogen. In this study, we compare the cytotoxic and clastogenic effects of Cr(VI) in human (Homo sapiens) and sperm whale (Physeter macrocephalus) skin fibroblasts. Our data show that increasing concentrations of both particulate and soluble Cr(VI) induce increasing amounts of cytotoxicity and clastogenicity in human and sperm whale skin cells. Furthermore, the data show that sperm whale cells are resistant to these effects exhibiting less cytotoxicity and genotoxicity than the human cells. Differences in Cr uptake accounted for some but not all of the differences in particulate and soluble Cr(VI) genotoxicity, although it did explain the differences in particulate Cr(VI) cytotoxicity. Altogether, the data indicate that Cr(VI) is a genotoxic threat to whales, but also suggest that whales have evolved cellular mechanisms to protect them against the genotoxicity of environmental agents such as Cr(VI). Copyright © 2011 Elsevier Inc. All rights reserved.

The results of interconnection of the evidence of professional exposure to genotoxic factors (regex) and cancer registry in the Czech Republic.

PubMed

Lehocká, Hana; Závacká, Ivona; Vavrošová, Jana; Janout, Vladimír

2017-03-01

The aim of this study is to analyze the genotoxic risks in the Moravian-Silesian Region in the Czech Republic and assess the significance of genotoxic factors in the etiology of cancer by bringing together the Registry of Occupational Exposure to Genotoxic Factors and the Cancer Registry and compare the rate of detected cancer in persons exposed to genotoxic factors via their work in the Moravian-Silesian Region with the occurrence of cancer in the population of the Czech Republic. The results show: (a) For the monitored group (748 person) for the period 1996-2008, according to gender, was no statistically significant difference in the incidence of oncological diseases compared to the population of the Czech Republic. (b) But statistically significant difference was found in the cases of oncological diseases in groups according to % AB.C. using the Cytogenetic analysis of human peripheral lymphocytes (CAPL). The highest incidence was in the group with a higher incidence of % AB.C. High values of % AB.C. may predict the development of oncological diseases.

Evolutionarily Distant Streptophyta Respond Differently to Genotoxic Stress

PubMed Central

Vágnerová, Radka; Lukešová, Alena; Lukeš, Martin; Rožnovská, Petra; Holá, Marcela; Fulnečková, Jana; Angelis, Karel J.

2017-01-01

Research in algae usually focuses on the description and characterization of morpho—and phenotype as a result of adaptation to a particular habitat and its conditions. To better understand the evolution of lineages we characterized responses of filamentous streptophyte green algae of the genera Klebsormidium and Zygnema, and of a land plant—the moss Physcomitrella patens—to genotoxic stress that might be relevant to their environment. We studied the induction and repair of DNA double strand breaks (DSBs) elicited by the radiomimetic drug bleomycin, DNA single strand breaks (SSB) as consequence of base modification by the alkylation agent methyl methanesulfonate (MMS) and of ultra violet (UV)-induced photo-dimers, because the mode of action of these three genotoxic agents is well understood. We show that the Klebsormidium and Physcomitrella are similarly sensitive to introduced DNA lesions and have similar rates of DSBs repair. In contrast, less DNA damage and higher repair rate of DSBs was detected in Zygnema, suggesting different mechanisms of maintaining genome integrity in response to genotoxic stress. Nevertheless, contrary to fewer detected lesions is Zygnema more sensitive to genotoxic treatment than Klebsormidium and Physcomitrella PMID:29149093

Evolutionarily Distant Streptophyta Respond Differently to Genotoxic Stress.

PubMed

Vágnerová, Radka; Lukešová, Alena; Lukeš, Martin; Rožnovská, Petra; Holá, Marcela; Fulnečková, Jana; Fajkus, Jiří; Angelis, Karel J

2017-11-17

Research in algae usually focuses on the description and characterization of morpho-and phenotype as a result of adaptation to a particular habitat and its conditions. To better understand the evolution of lineages we characterized responses of filamentous streptophyte green algae of the genera Klebsormidium and Zygnema , and of a land plant-the moss Physcomitrella patens -to genotoxic stress that might be relevant to their environment. We studied the induction and repair of DNA double strand breaks (DSBs) elicited by the radiomimetic drug bleomycin, DNA single strand breaks (SSB) as consequence of base modification by the alkylation agent methyl methanesulfonate (MMS) and of ultra violet (UV)-induced photo-dimers, because the mode of action of these three genotoxic agents is well understood. We show that the Klebsormidium and Physcomitrella are similarly sensitive to introduced DNA lesions and have similar rates of DSBs repair. In contrast, less DNA damage and higher repair rate of DSBs was detected in Zygnema , suggesting different mechanisms of maintaining genome integrity in response to genotoxic stress. Nevertheless, contrary to fewer detected lesions is Zygnema more sensitive to genotoxic treatment than Klebsormidium and Physcomitrella .

Mixture genotoxicity of 2,4-dichlorophenoxyacetic acid, acrylamide, and maleic hydrazide on human Caco-2 cells assessed with comet assay.

PubMed

Syberg, Kristian; Binderup, Mona-Lise; Cedergreen, Nina; Rank, Jette

2015-01-01

Assessment of genotoxic properties of chemicals is mainly conducted only for single chemicals, without taking mixture genotoxic effects into consideration. The current study assessed mixture effects of the three known genotoxic chemicals, 2,4-dichlorophenoxyacetic acid (2,4-D), acrylamide (AA), and maleic hydrazide (MH), in an experiment with a fixed ratio design setup. The genotoxic effects were assessed with the single-cell gel electrophoresis assay (comet assay) for both single chemicals and the ternary mixture. The concentration ranges used were 0-1.4, 0-20, and 0-37.7 mM for 2,4-D, AA, and MH, respectively. Mixture toxicity was tested with a fixed ratio design at a 10:23:77% ratio for 2.4-D:AA:MH. Results indicated that the three chemicals yielded a synergistic mixture effect. It is not clear which mechanisms are responsible for this interaction. A few possible interactions are discussed, but further investigations including in vivo studies are needed to clarify how important these more-than-additive effects are for risk assessment.

In vitro genotoxicity testing strategy for nanomaterials and the adaptation of current OECD guidelines

PubMed Central

Doak, S.H.; Manshian, B.; Jenkins, G.J.S.; Singh, N.

2012-01-01

There is a pressing requirement to define a hazard identification and risk management strategy for nanomaterials due to the rapid growth in the nanotechnology industry and their promise of life-style revolutions through the development of wide-ranging nano-containing consumer products. Consequently, a battery of well defined and appropriate in vitro assays to assess a number of genotoxicity endpoints is required to minimise extensive and costly in vivo testing. However, the validity of the established protocols in current OECD recognised genotoxicity assays for nanomaterials is currently being questioned. In this report, we therefore consider the in vitro OECD genotoxicity test battery including the Ames, micronucleus and HPRT forward mutation assays, and their potential role in the safety assessment of nanomaterial induced DNA damage in vitro. PMID:21971291

Genotoxic properties of haloacetonitriles: drinking water by-products of chlorine disinfection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, F.B.; Schenck, K.M.; Mattox, J.K.

Chlorinated and brominated haloacetonitriles (HAN), known drinking water contaminants which form during chlorine disinfection, were investigated for genotoxic activity. The HAN produced DNA strand breaks in cultured human lymphoblastic (CCRF-CEM) cells, bound to the nucleophilic trapping agent 4-(p-nitrobenzyl)pyridine and formed a covalent bond to polyadenylic acid in a cell-free reaction system. Thus, we have demonstrated that these chemicals are genotoxic, which would indicate a potential for carcinogenic activity and for human health hazard.

Electrochemical Genotoxicity Assay Based on a SOS/umu Test Using Hydrodynamic Voltammetry in a Droplet

PubMed Central

Kuramitz, Hideki; Sazawa, Kazuto; Nanayama, Yasuaki; Hata, Noriko; Taguchi, Shigeru; Sugawara, Kazuharu; Fukushima, Masami

2012-01-01

The SOS/umu genotoxicity assay evaluates the primary DNA damage caused by chemicals from the β-galactosidase activity of S. typhimurium. One of the weaknesses of the common umu test system based on spectrophotometric detection is that it is unable to measure samples containing a high concentration of colored dissolved organic matters, sediment, and suspended solids. However, umu tests with electrochemical detection techniques prove to be a better strategy because it causes less interference, enables the analysis of turbid samples and allows detection even in small volumes without loss of sensitivity. Based on this understanding, we aim to develop a new umu test system with hydrodynamic chronoamperometry using a rotating disk electrode (RDE) in a microliter droplet. PAPG when used as a substrate is not electroactive at the potential at which PAP is oxidized to p-quinone imine (PQI), so the current response of chronoamperometry resulting from the oxidation of PAP to PQI is directly proportional to the enzymatic activity of S. typhimurium. This was achieved by performing genotoxicity tests for 2-(2-furyl)-3-(5-nitro-2-furyl)-acrylamide (AF-2) and 2-aminoanthracene (2-AA) as model genotoxic compounds. The results obtained in this study indicated that the signal detection in the genotoxicity assay based on hydrodynamic voltammetry was less influenced by the presence of colored components and sediment particles in the samples when compared to the usual colorimetric signal detection. The influence caused by the presence of humic acids (HAs) and artificial sediment on the genotoxic property of selected model compounds such as 4-nitroquinoline-N-oxide (4-NQO), 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), 1,8-dinitropyrene (1,8-DNP) and 1-nitropyrene (1-NP) were also investigated. The results showed that the genotoxicity of 1-NP and MX changed in the presence of 10 mg·L−1 HAs. The genotoxicity of tested chemicals with a high hydrophobicity such as 1,8-DNP and 1-NP were decreased substantially with the presence of 1 g·L−1 sediment. This was not observed in the case of genotoxins with a low log Kow value. PMID:23242275

Identification of early target genes of aflatoxin B1 in human hepatocytes, inter-individual variability and comparison with other genotoxic compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Josse, Rozenn; Dumont, Julie; Fautrel, Alain

Gene expression profiling has recently emerged as a promising approach to identify early target genes and discriminate genotoxic carcinogens from non-genotoxic carcinogens and non-carcinogens. However, early gene changes induced by genotoxic compounds in human liver remain largely unknown. Primary human hepatocytes and differentiated HepaRG cells were exposed to aflatoxin B1 (AFB1) that induces DNA damage following enzyme-mediated bioactivation. Gene expression profile changes induced by a 24 h exposure of these hepatocyte models to 0.05 and 0.25 μM AFB1 were analyzed by using oligonucleotide pangenomic microarrays. The main altered signaling pathway was the p53 pathway and related functions such as cellmore » cycle, apoptosis and DNA repair. Direct involvement of the p53 protein in response to AFB1 was verified by using siRNA directed against p53. Among the 83 well-annotated genes commonly modulated in two pools of three human hepatocyte populations and HepaRG cells, several genes were identified as altered by AFB1 for the first time. In addition, a subset of 10 AFB1-altered genes, selected upon basis of their function or tumor suppressor role, was tested in four human hepatocyte populations and in response to other chemicals. Although they exhibited large variable inter-donor fold-changes, several of these genes, particularly FHIT, BCAS3 and SMYD3, were found to be altered by various direct and other indirect genotoxic compounds and unaffected by non-genotoxic compounds. Overall, this comprehensive analysis of early gene expression changes induced by AFB1 in human hepatocytes identified a gene subset that included several genes representing potential biomarkers of genotoxic compounds. -- Highlights: ► Gene expression profile changes induced by aflatoxin B1 in human hepatocytes. ► AFB1 modulates various genes including tumor suppressor genes and proto-oncogenes. ► Important inter-individual variations in the response to AFB1. ► Some genes also altered by other genotoxic compounds requiring or not bioactivation.« less

Ordered Conformational Changes in Damaged DNA Induced by Nucleotide Excision Repair Factors*

PubMed Central

Tapias, Angels; Auriol, Jerome; Forget, Diane; Enzlin, Jacqueline H.; Schärer, Orlando D; Coin, Frederic; Coulombe, Benoit; Egly, Jean-Marc

2015-01-01

In response to genotoxic attacks, cells activate sophisticated DNA repair pathways such as nucleotide excision repair (NER), which consists of damage removal via dual incision and DNA resynthesis. Using permanganate footprinting as well as highly purified factors, we show that NER is a dynamic process that takes place in a number of successive steps during which the DNA is remodeled around the lesion in response to the various NER factors. XPC/HR23B first recognizes the damaged structure and initiates the opening of the helix from position −3 to +6. TFIIH is then recruited and, in the presence of ATP, extends the opening from position −6 to +6; it also displaces XPC downstream from the lesion, thereby providing the topological structure for recruiting XPA and RPA, which will enlarge the opening. Once targeted by XPG, the damaged DNA is further melted from position −19 to +8. XPG and XPF/ERCC1 endo-nucleases then cut the damaged DNA at the limit of the opened structure that was previously “labeled” by the positioning of XPC/HR23B and TFIIH. PMID:14981083

Anti-genotoxicity of trans-anethole and eugenol in mice.

PubMed

Abraham, S K

2001-05-01

The naturally occurring flavouring agents trans-anethole and eugenol were evaluated for antigenotoxic effects in mice. The test doses of trans-anethole (40-400 mg/kg body weight) and eugenol (50-500 mg/kg weight) were administered by gavage 2 and 20 h before the genotoxins were injected intraperitoneally. Anti-genotoxic effects were assessed in the mouse bone marrow micronucleus test. Pretreatment with trans-anethole and eugenol led to significant antigenotoxic effects against cyclophosphamide (CPH), procarbazine (PCB), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and urethane (URE). In addition, trans-anethole inhibited the genotoxicity of ethyl methane sulfonate (EMS). Both trans-anethole and eugenol exerted dose-related antigenotoxic effects against PCB and URE. There was no significant increase in genotoxicity when trans-anethole (40-400 mg/kg body weight) and eugenol (50-500 mg/kg body weight) were administered alone.

Assessment of genotoxic effects of flumorph by the comet assay in mice organs.

PubMed

Zhang, T; Zhao, Q; Zhang, Y; Ning, J

2014-03-01

The present study investigated the genotoxic effects of flumorph in various organs (brain, liver, spleen, kidney and sperm) of mice. The DNA damage, measured as comet tail length (µm), was determined using the alkaline comet assay. The comet assay is a sensitive assay for the detection of genotoxicity caused by flumorph using mice as a model. Statistically significant increases in comet assay for both dose-dependent and duration-dependent DNA damage were observed in all the organs assessed. The organs exhibited the maximum DNA damage in 96 h at 54 mg/kg body weight. Brain showed maximum DNA damage followed by spleen > kidney > liver > sperm. Our data demonstrated that flumorph had induced systemic genotoxicity in mammals as it caused DNA damage in all tested vital organs, especially in brain and spleen.

Plant genotoxicity: a molecular cytogenetic approach in plant bioassays.

PubMed

Maluszynska, Jolanta; Juchimiuk, Jolanta

2005-06-01

It is important for the prevention of DNA changes caused by environment to understand the biological consequences of DNA damages and their molecular modes of action that lead to repair or alterations of the genetic material. Numerous genotoxicity assay systems have been developed to identify DNA reactive compounds. The available data show that plant bioassays are important tests in the detection of genotoxic contamination in the environment and the establishment of controlling systems. Plant system can detect a wide range of genetic damage, including gene mutations and chromosome aberrations. Recently introduced molecular cytogenetic methods allow analysis of genotoxicity, both at the chromosomal and DNA level. FISH gives a new possibility of the detection and analysis of chromosomal rearrangements in a great detail. DNA fragmentation can be estimated using the TUNEL test and the single cell gel electrophoresis (Comet assay).

Toxicological assessment of Anionic Methacrylate Copolymer: I. Characterization, bioavailability and genotoxicity.

PubMed

Eisele, Johanna; Haynes, Geoff; Kreuzer, Knut; Hall, Caroline

2016-12-01

Anionic Methacrylate Copolymer (AMC) is a fully polymerized copolymer used in the pharmaceutical industry as an enteric/delayed-release coating to permit the pH-dependent release of active ingredients in the gastrointestinal tract from oral dosage forms. This function is of potential use for food supplements. Oral administration of radiolabeled copolymer to rats resulted in the detection of chemically unchanged copolymer in the feces, with negligible absorption (<0.1%). AMC is therefore determined not to be bioavailable. Within a genotoxicity test battery AMC did not show any evidence of genotoxicity in bacteria and mammalian cells. Furthermore, no genotoxic effects occurred in vivo within a micronucleus test. There would therefore appear to be no safety concerns under intended conditions of oral use for the discussed toxicological endpoints. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of Boron Toxicity on Oxidative Stress and Genotoxicity in Wheat (Triticum aestivum L.).

PubMed

Çatav, Şükrü Serter; Genç, Tuncer Okan; Kesik Oktay, Müjgan; Küçükakyüz, Köksal

2018-04-01

Boron (B) toxicity, which occurs in semi-arid and arid environments, can adversely affect the growth and yield of many plants. The aim of this study was to determine the effects of different concentrations of boric acid (3, 6, 9 and 12 mM) on growth, oxidative stress and genotoxicity parameters in root and shoot tissues of wheat seedlings. Our results indicate that B stress inhibits root and shoot growth of wheat in a concentration-dependent manner, and leads to increases in TBARS and H 2 O 2 contents in shoot tissue. Moreover, our findings suggest that high concentrations of B may exert a genotoxic effect on wheat. To the best of our knowledge, this is the first report to evaluate the effect of B stress on genotoxicity in both root and shoot tissues of wheat.

Evaluation of Cytotoxicity and Genotoxicity of Acacia aroma Leaf Extracts

PubMed Central

Mattana, C. M.; Cangiano, M. A.; Alcaráz, L. E.; Sosa, A.; Escobar, F.; Sabini, C.; Sabini, L.; Laciar, A. L.

2014-01-01

Acacia aroma, native plant from San Luis, Argentina, is commonly used as antiseptic and for healing of wounds. The present study was conducted to investigate the in vitro cytotoxicity and genotoxicity of hot aqueous extract (HAE) and ethanolic extract (EE) of A. aroma. The cytotoxic activity was assayed by neutral red uptake assay on Vero cell. Cell treatment with a range from 100 to 5000 μg/mL of HAE and EE showed that 500 μg/mL and 100 μg/mL were the maximum noncytotoxic concentrations, respectively. The CC50 was 658 μg/mL for EE and 1020 μg/mL for HAE. The genotoxicity was tested by the single-cell gel electrophoresis comet assay. The results obtained in the evaluation of DNA cellular damage exposed to varied concentrations of the HAE showed no significant genotoxic effect at range of 1–20 mg/mL. The EE at 20 mg/mL showed moderate genotoxic effect related to the increase of the DNA percentage contained in tail of the comet; DNA was classified in category 2. At concentrations below 5 mg/mL, the results of cytotoxicity and genotoxicity of aqueous and ethanolic extracts of Acacia aroma guarantee the safety at cell and genomic level. However further studies are needed for longer periods including animal models to confirm the findings. PMID:25530999

Ameliorative effects of curcumin against lead induced toxicity in human peripheral blood lymphocytes culture.

PubMed

Nariya, Ankit; Pathan, Ambar; Shah, Naumita; Chettiar, Shiva; Patel, Alpesh; Dattani, Jignasha; Chandel, Divya; Rao, Mandava; Jhala, Devendrasinh

2018-01-01

Lead, a heavy metal and multifaceted toxicant, is well studied for its distribution and toxicity in ecosystem, yet there is no consensus on its amelioration by any synthetic or phytochemical compounds. Curcumin, a known antioxidant and dietary element, is a well-known herb, for its therapeutic uses and having a wide spectrum of its beneficial properties against several adverse effects. Hence, the current study was taken into consideration to evaluate the ameliorative effects of curcumin (3.87 μM, i.e. 1.43 μg/ml) against lead acetate (doses: 10 -6 M, i.e. 0.379 μg/ml and 10 -4 M, i.e. 37.9 μg/ml, durations: 24 h and 69 h) induced genotoxicity and oxidative stress in human peripheral blood lymphocyte cultures (PBLC). On one hand, antigenotoxic and antioxidative potentials of curcumin against lead were simultaneously evaluated by the array of genotoxicity and oxidative stress indices. The result postulated that lead acetate showed dose- and duration-dependent increase in both genotoxicity and oxidative stress whereas curcumin, when added along with lead acetate, showed the significant amelioration in all genotoxic and oxidative stress-related indices. The study indicated that, due to alteration in antioxidant defense system, there is an adverse genotoxic effect of lead. On the other hand, curcumin, a potent antidote, can protect chromatin material against lead -mediated genotoxicity by balancing the activity of antioxidant defense system.

Protective Effects of Quercetin against Dimethoate-Induced Cytotoxicity and Genotoxicity in Allium sativum Test

PubMed Central

Ahmad, Waseem; Shaikh, Sibhghatulla; Nazam, Nazia; Lone, Mohammad Iqbal

2014-01-01

The present investigation was directed to study the possible protective activity of quercetin—a natural antioxidant against dimethoate-induced cyto- and genotoxicity in meristematic cells of Allium sativum. So far there is no report on the biological properties of quercetin in plant test systems. Chromosome breaks, multipolar anaphase, stick chromosome, and mitotic activity were undertaken in the current study as markers of cyto- and genotoxicity. Untreated control, quercetin controls (@ 5, 10 and 20 μg/mL for 3 h), and dimethoate exposed groups (@ 100 and 200 μg/mL for 3 h) were maintained. For protection against cytogenotoxicity, the root tip cells treated with dimethoate at 100 and 200 μg/mL for 3 h and quercetin treatment at 5, 10, and 20 μg/mL for 16 h, prior to dimethoate treatment, were undertaken. Quercetin was found to be neither cytotoxic nor genotoxic in Allium sativum control at these doses. A significant increase (P < 0.05) in chromosomal aberrations was noted in dimethoate treated Allium. Pretreatment of Allium sativum with quercetin significantly (P < 0.05) reduced dimethoate-induced genotoxicity and cytotoxicity in meristematic cells, and these effects were dose dependent. In conclusion, quercetin has a protective role in the abatement of dimethoate-induced cyto- and genotoxicity in the meristematic cells of Allium sativum that resides, at least in part, on its antioxidant effects. PMID:27379342

Protective Effects of Quercetin against Dimethoate-Induced Cytotoxicity and Genotoxicity in Allium sativum Test.

PubMed

Ahmad, Waseem; Shaikh, Sibhghatulla; Nazam, Nazia; Lone, Mohammad Iqbal

2014-01-01

The present investigation was directed to study the possible protective activity of quercetin-a natural antioxidant against dimethoate-induced cyto- and genotoxicity in meristematic cells of Allium sativum. So far there is no report on the biological properties of quercetin in plant test systems. Chromosome breaks, multipolar anaphase, stick chromosome, and mitotic activity were undertaken in the current study as markers of cyto- and genotoxicity. Untreated control, quercetin controls (@ 5, 10 and 20 μg/mL for 3 h), and dimethoate exposed groups (@ 100 and 200 μg/mL for 3 h) were maintained. For protection against cytogenotoxicity, the root tip cells treated with dimethoate at 100 and 200 μg/mL for 3 h and quercetin treatment at 5, 10, and 20 μg/mL for 16 h, prior to dimethoate treatment, were undertaken. Quercetin was found to be neither cytotoxic nor genotoxic in Allium sativum control at these doses. A significant increase (P < 0.05) in chromosomal aberrations was noted in dimethoate treated Allium. Pretreatment of Allium sativum with quercetin significantly (P < 0.05) reduced dimethoate-induced genotoxicity and cytotoxicity in meristematic cells, and these effects were dose dependent. In conclusion, quercetin has a protective role in the abatement of dimethoate-induced cyto- and genotoxicity in the meristematic cells of Allium sativum that resides, at least in part, on its antioxidant effects.

Cytotoxicity and Genotoxicity Assessment of Sandalwood Essential Oil in Human Breast Cell Lines MCF-7 and MCF-10A.

PubMed

Ortiz, Carmen; Morales, Luisa; Sastre, Miguel; Haskins, William E; Matta, Jaime

2016-01-01

Sandalwood essential oil (SEO) is extracted from Santalum trees. Although α-santalol, a main constituent of SEO, has been studied as a chemopreventive agent, the genotoxic activity of the whole oil in human breast cell lines is still unknown. The main objective of this study was to assess the cytotoxic and genotoxic effects of SEO in breast adenocarcinoma (MCF-7) and nontumorigenic breast epithelial (MCF-10A) cells. Proteins associated with SEO genotoxicity were identified using a proteomics approach. Commercially available, high-purity, GC/MS characterized SEO was used to perform the experiments. The main constituents reported in the oil were (Z)-α-santalol (25.34%), (Z)-nuciferol (18.34%), (E)-β-santalol (10.97%), and (E)-nuciferol (10.46%). Upon exposure to SEO (2-8 μg/mL) for 24 hours, cell proliferation was determined by the MTT assay. Alkaline and neutral comet assays were used to assess genotoxicity. SEO exposure induced single- and double-strand breaks selectively in the DNA of MCF-7 cells. Quantitative LC/MS-based proteomics allowed identification of candidate proteins involved in this response: Ku70 (p = 1.37E - 2), Ku80 (p = 5.8E - 3), EPHX1 (p = 3.3E - 3), and 14-3-3ζ (p = 4.0E - 4). These results provide the first evidence that SEO is genotoxic and capable of inducing DNA single- and double-strand breaks in MCF-7 cells.

Cytotoxicity and Genotoxicity Assessment of Sandalwood Essential Oil in Human Breast Cell Lines MCF-7 and MCF-10A

PubMed Central

Ortiz, Carmen; Morales, Luisa; Sastre, Miguel; Haskins, William E.; Matta, Jaime

2016-01-01

Sandalwood essential oil (SEO) is extracted from Santalum trees. Although α-santalol, a main constituent of SEO, has been studied as a chemopreventive agent, the genotoxic activity of the whole oil in human breast cell lines is still unknown. The main objective of this study was to assess the cytotoxic and genotoxic effects of SEO in breast adenocarcinoma (MCF-7) and nontumorigenic breast epithelial (MCF-10A) cells. Proteins associated with SEO genotoxicity were identified using a proteomics approach. Commercially available, high-purity, GC/MS characterized SEO was used to perform the experiments. The main constituents reported in the oil were (Z)-α-santalol (25.34%), (Z)-nuciferol (18.34%), (E)-β-santalol (10.97%), and (E)-nuciferol (10.46%). Upon exposure to SEO (2–8 μg/mL) for 24 hours, cell proliferation was determined by the MTT assay. Alkaline and neutral comet assays were used to assess genotoxicity. SEO exposure induced single- and double-strand breaks selectively in the DNA of MCF-7 cells. Quantitative LC/MS-based proteomics allowed identification of candidate proteins involved in this response: Ku70 (p = 1.37E − 2), Ku80 (p = 5.8E − 3), EPHX1 (p = 3.3E − 3), and 14-3-3ζ (p = 4.0E − 4). These results provide the first evidence that SEO is genotoxic and capable of inducing DNA single- and double-strand breaks in MCF-7 cells. PMID:27293457

Influence of Serum Levels of Vitamins A, D, and E as well as Vitamin D Receptor Polymorphisms on Micronucleus Frequencies and Other Biomarkers of Genotoxicity in Workers Exposed to Formaldehyde.

PubMed

Ladeira, Carina; Pádua, Mário; Veiga, Luísa; Viegas, Susana; Carolino, Elisabete; Gomes, Manuel C; Brito, Miguel

2015-01-01

Formaldehyde is classified as carcinogenic to humans, making it a major concern, particularly in occupational settings. Fat-soluble vitamins, such as vitamins A, D, and E, are documented as antigenotoxic and antimutagenic and also correlate with the cell antioxidant potential. This study investigates the influence of these vitamins on genotoxicity biomarkers of formaldehyde-exposed hospital workers. The target population were hospital workers exposed to formaldehyde (n = 55). Controls were nonexposed individuals (n = 80). The most used genotoxicity biomarkers were the cytokinesis-block micronucleus assay for lymphocytes and the micronucleus test for exfoliated buccal cells. Vitamins A and E were determined by high-performance liquid chromatography with a diode array detector (HPLC-DAD) and vitamin D receptor (VDR) polymorphisms by real-time PCR. Significant correlations were found between genotoxicity biomarkers and between vitamins A and E in controls. Multiple regression showed that vitamin A was significantly associated with a higher mean of nucleoplasmic bridges (p < 0.001), and vitamin E was significantly associated with a decreased frequency of nuclear buds (p = 0.045) in the exposed group. No effect of vitamin D was observed. The VDRBsmI TT genotype carriers presented higher means of all the genotoxicity biomarkers; however, we found no significant associations. The study suggests that vitamin levels may modulate direct signs of genotoxicity. © 2016 S. Karger AG, Basel.

Environmental nitration processes enhance the mutagenic potency of aromatic compounds.

PubMed

Bonnefoy, Aurélie; Chiron, Serge; Botta, Alain

2012-05-01

This work is an attempt to establish if aromatic nitration processes are always associated with an increase of genotoxicity. We determined the mutagenic and genotoxic effects of Benzene (B), Nitrobenzene (NB), Phenol (P), 2-Nitrophenol (2-NP), 2,4-Dinitrophenol (2,4-DNP), Pyrene (Py), 1-Nitropyrene (1-NPy), 1,3-Dinitropyrene (1,3-DNPy), 1,6-Dinitropyrene (1,6-DNPy), and 1,8-Dinitropyrene (1,8-DNPy). The mutagenic activities were evaluated with umuC test in presence and in absence of metabolic activation with S9 mix. Then, we used both cytokinesis-blocked micronucleus (CBMN) assay, in combination with fluorescent in situ hybridization (FISH) of human pan-centromeric DNA probes on human lymphocytes in order to evaluate the genotoxic effects. Analysis of all results shows that nitro polycyclic aromatic hydrocarbons (PAHs) are definitely environmental genotoxic/mutagenic hazards and confirms that environmental aromatic nitration reactions lead to an increase in genotoxicity and mutagenicity properties. Particularly 1-NPy and 1,8-DNPy can be considered as human potential carcinogens. They seem to be significant markers of the genotoxicity, mutagenicity, and potential carcinogenicity of complex PAHs mixtures present in traffic emission and industrial environment. In prevention of environmental carcinogenic risk 1-NPy and 1,8-DNPy must therefore be systematically analyzed in environmental complex mixtures in association with combined umuC test, CBMN assay, and FISH on cultured human lymphocytes. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012. Copyright © 2010 Wiley Periodicals, Inc.

Genotoxicity in native fish associated with agricultural runoff events

USGS Publications Warehouse

Whitehead, Andrew; Kuivila, Kathryn; Orlando, James L.; Kotelevtsev, S.; Anderson, Susan L.

2004-01-01

The primary objective of the present study was to test whether agricultural chemical runoff was associated with in-stream genotoxicity in native fish. Using Sacramento sucker (Catostomus occidentalis), we combined field-caging experiments in an agriculturally dominated watershed with controlled laboratory exposures to field-collected water samples, and we coupled genotoxicity biomarker measurements in fish with bacterial mutagenicity analysis of water samples. We selected DNA strand breakage as a genotoxicity biomarker and Ames Salmonella mutagenicity tests as a second, supporting indicator of genotoxicity. Data from experiments conducted during rainfall runoff events following winter application of pesticides in 2000 and 2001 indicated that DNA strand breaks were significantly elevated in fish exposed to San Joaquin River (CA, USA) water (38.8, 28.4, and 53.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively) compared with a nearby reference site (15.4, 8.7, and 12.6% DNA strand breakage in year 2000 field, year 2000 lab, and year 2001 field exposures, respectively). Time-course measurements in field experiments supported a linkage between induction of DNA strand breakage and the timing of agricultural runoff. San Joaquin River water also caused significant reversion mutation in two Ames Salmonella tester strains. Salmonella mutagenicity corroborated in-stream effects, further strengthening a causal relationship between runoff events and genotoxicity. Potentially responsible agents are discussed in the context of timing of runoff events in the field, concordance between laboratory and field exposures, pesticide application patterns in the drainage, and analytical chemistry data.

Genotoxicity testing of cooked cured meat pigment (CCMP) and meat emulsion coagulates prepared with CCMP.

PubMed

Stevanović, M; Cadez, P; Zlender, B; Filipic, M

2000-07-01

The preformed cooked cured meat pigment (CCMP) synthesized directly from bovine red blood cells or through a hemin intermediate was found to be a viable colorant for application to comminuted pork as a nitrite substitute. However the genotoxicity of CCMP and meat emulsion coagulates prepared with CCMP has not been evaluated. Therefore the objectives of this work were to investigate genotoxicity of CCMP and the influence of CCMP addition on genotoxicity and the content of residual nitrite in model meat emulsion coagulates. Meat emulsions were prepared from white (musculus longissimus dorsi) and red (musculus quadriceps femoris) pork muscles with two different amounts of synthesized pigment CCMP. Comparatively, emulsions with fixed addition of nitrite salt and emulsions without any addition for color development were made. Genotoxicity of CCMP and meat emulsion coagulates was tested with the SOS/umu test and the Ames test. Neither CCMP nor meat emulsion coagulates prepared with CCMP or nitrite salt were genotoxic in the SOS/umu test. In the Ames test using Salmonella Typhimurium strains TA98 and TA100 samples of coagulates prepared with CCMP and with nitrite showed weak mutagenic activity in Salmonella Typhimurium strain TA100 but only in the absence of the metabolic activation, while CCMP was not mutagenic. Coagulates prepared with CCMP contained significantly less residual nitrite than coagulates prepared with nitrite salt. These results indicate that from the human health standpoint the substitution of nitrite salt with CCMP would be highly recommendable.

Measurement of micronuclei and internal dose in mice demonstrates that 3-monochloropropane-1,2-diol (3-MCPD) has no genotoxic potency in vivo.

PubMed

Aasa, Jenny; Törnqvist, Margareta; Abramsson-Zetterberg, Lilianne

2017-11-01

In this study 3-monochloropropane-1,2-diol (3-MCPD), a compound that appears as contaminant in refined cooking oils, has been studied with regard to genotoxicity in vivo (mice) with simultaneous measurement of internal dose using state-of-the-art methodologies. Genotoxicity (chromosomal aberrations) was measured by flow cytometry with dual lasers as the frequency of micronuclei in erythrocytes in peripheral blood from BalbC mice intraperitoneally exposed to 3-MCPD (0, 50, 75, 100, 125 mg/kg). The internal doses of 3-MCPD in the mice were calculated from N-(2,3-dihydroxypropyl)-valine adducts to hemoglobin (Hb), quantified at very low levels by high-resolution mass spectrometry. Convincing evidence for absence of genotoxic potency in correlation to measured internal doses in the mice was demonstrated, despite relatively high administered doses of 3-MCPD. The results are discussed in relation to another food contaminant that is formed as ester in parallel to 3-MCPD esters in oil processing, i.e. glycidol, which has been studied previously by us in a similar experimental setup. Glycidol has been shown to be genotoxic, and in addition to have ca. 1000 times higher rate of adduct formation compared to that observed for 3-MCPD. The conclusion is that at simultaneous exposure to 3-MCPD and glycidol the concern about genotoxicity would be glycidol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Amplification of arsenic genotoxicity by TiO2 nanoparticles in mammalian cells: new insights from physicochemical interactions and mitochondria.

PubMed

Wang, Xinan; Liu, Yun; Wang, Juan; Nie, Yaguang; Chen, Shaopeng; Hei, Tom K; Deng, Zhaoxiang; Wu, Lijun; Zhao, Guoping; Xu, An

2017-10-01

Titanium dioxide nanoparticles (TiO 2 NPs) have shown great adsorption capacity for arsenic (As); however, the potential impact of TiO 2 NPs on the behavior and toxic responses of As remains largely unexplored. In the present study, we focused on the physicochemical interaction between TiO 2 NPs and As(III) to clarify the underlying mechanisms involved in their synergistic genotoxic effect on mammalian cells. Our data showed that As(III) mainly interacted with TiO 2 NPs by competitively occupying the sites of hydroxyl groups on the surface of TiO 2 NP aggregates, resulting in more aggregation of TiO 2 NPs. Although TiO 2 NPs at concentrations used here had no cytotoxic or genotoxic effects on cells, they efficiently increased the genotoxicity of As(III) in human-hamster hybrid (A L ) cells. The synergistic genotoxicity of TiO 2 NPs and As(III) was partially inhibited by various endocytosis pathway inhibitors while it was completely blocked by an As(III)-specific chelator. Using a mitochondrial membrane potential fluorescence probe, a reactive oxygen species (ROS) probe together with mitochondrial DNA-depleted ρ 0 A L cells, we discovered that mitochondria were essential for mediating the synergistic DNA-damaging effects of TiO 2 NPs and As(III). These data provide novel mechanistic proof that TiO 2 NPs enhanced the genotoxicity of As(III) via physicochemical interactions, which were mediated by mitochondria-dependent ROS.

Technological response to economic disruption: The role of new technologies in mitigating exogenous economic shocks

NASA Astrophysics Data System (ADS)

Spencer, Aron Scott

2003-07-01

The three essays in this dissertation deal with the role of technology in mitigating economic disruption. Much research has been done on the disruptive effects of technology; in contrast, these essays look at how technology can be used to reduce the effects of exogenous disruptions. Each essay looks at the issue at a different level; the first at the firm level, the second at the industry level and the final essay at the level of the national economy. The first essay examines the options and possible strategies for firms faced with increased instability in their electricity supply, as recently occurred in California. This paper develops response strategies for companies affected by an electrical crisis. These responses fall into three categories: Lead, Follow, or Get Out of the State. The technologies available to companies choosing to lead are reviewed, along with constraints to their adoption. From these strategies, it can be shown that areas with unstable electrical markets can expect a loss of firms to locales with less risk and uncertainty, unless governments adopt policies promoting distributed generation. The second essay projects the economic impacts of the adoption of high-temperature superconductor (FITS) technologies in electric generation, transmission, and distribution systems. Three technologies utilizing high-temperature superconductors are analyzed for their potential impact on the electrical utility industry. Distributed superconducting magnetic energy storage systems (D-SMES), superconducting cable, and HTS generators are each described along with their possible uses in the electrical utility industry. The economic impact of these technologies is then projected, along with a comparison between them and conventional technologies. The third essay deals with the role of technology in mitigating the economic effects of the reaction to terrorist attacks. In the wake of the terrorist attacks of September 11, 2001, public and private investments are being diverted from productive to protective uses. This essay examines the possible economic effects of such a reallocation of resources, and shows how this shift in investment is likely to dampen long-term economic growth. Whether one uses Solow growth model derivatives or Austrian school methods, the diversion of resources has negative implications for economic growth.

Nitrosative stress induces DNA strand breaks but not caspase mediated apoptosis in a lung cancer cell line

PubMed Central

Bentz, Brandon G; Hammer, Neal D; Radosevich, James A; Haines, G Kenneth

2004-01-01

Background Key steps crucial to the process of tumor progression are genomic instability and escape from apoptosis. Nitric oxide and its interrelated reactive intermediates (collectively denoted as NOX) have been implicated in DNA damage and mutational events leading to cancer development, while also being implicated in the inhibition of apoptosis through S-nitrosation of key apoptotic enzymes. The purpose of this study was to explore the interrelationship between NOX-mediated DNA strand breaks (DSBs) and apoptosis in cultured tumor cell lines. Methods Two well-characterized cell lines were exposed to increasing concentrations of exogenous NOX via donor compounds. Production of NOX was quantified by the Greiss reaction and spectrophotometery, and confirmed by nitrotyrosine immunostaining. DSBs were measured by the alkaline single-cell gel electrophoresis assay (the COMET assay), and correlated with cell viability by the MTT assay. Apoptosis was analyzed both by TUNEL staining and Annexin V/propidium iodine FACS. Finally, caspase enzymatic activity was measured using an in-vitro fluorogenic caspase assay. Results Increases in DNA strand breaks in our tumor cells, but not in control fibroblasts, correlated with the concentration as well as rate of release of exogenously administered NOX. This increase in DSBs did not correlate with an increase in cell death or apoptosis in our tumor cell line. Finally, this lack of apoptosis was found to correlate with inhibition of caspase activity upon exposure to thiol- but not NONOate-based NOX donor compounds. Conclusions Genotoxicity appears to be highly interrelated with both the concentration and kinetic delivery of NOX. Moreover, alterations in cell apoptosis can be seen as a consequence of the explicit mechanisms of NOX delivery. These findings lend credence to the hypothesis that NOX may play an important role in tumor progression, and underscores potential pitfalls which should be considered when developing NOX-based chemotherapeutic agents. PMID:15617570

Fruits and vegetables protect against the genotoxicity of heterocyclic aromatic amines activated by human xenobiotic-metabolizing enzymes expressed in immortal mammalian cells.

PubMed

Platt, K L; Edenharder, R; Aderhold, S; Muckel, E; Glatt, H

2010-12-21

Heterocyclic aromatic amines (HAAs) can be formed during the cooking of meat and fish at elevated temperatures and are associated with an increased risk for cancer. On the other hand, epidemiological findings suggest that foods rich in fruits and vegetables can protect against cancer. In the present study three teas, two wines, and the juices of 15 fruits and 11 vegetables were investigated for their protective effect against the genotoxic effects of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). To closely mimic the enzymatic activation of these HAAs in humans, genetically engineered V79 Chinese hamster fibroblasts were employed that express human cytochrome P450-dependent monooxygenase (hCYP) 1A2 (responsible for the first step of enzymatic activation) and human N(O)-acetyltransferase (hNAT) 2*4 or human sulfotransferase (hSULT)1A1*1 (responsible for the second step of enzymatic activation): V79-hCYP1A2-hNAT2*4 for IQ activation and V79-hCYP1A2-hSULT1A1*1 for PhIP activation. HAA genotoxicity was determined by use of the comet assay. Black, green and rooibos tea moderately reduced the genotoxicity of IQ (IC(50)=0.8-0.9%), whereas red and white wine were less active. From the fruit juices, sweet cherry juice exhibited the highest inhibitory effect on IQ genotoxicity (IC(50)=0.17%), followed by juices from kiwi fruit, plum and blueberry (IC(50)=0.48-0.71%). The juices from watermelon, blackberry, strawberry, black currant, and Red delicious apple showed moderate suppression, whereas sour cherry, grapefruit, red currant, and pineapple juices were only weakly active. Granny Smith apple juice and orange juice proved inactive. Of the vegetable juices, strong inhibition of IQ genotoxicity was only seen with spinach and onion juices (IC(50)=0.42-0.54%). Broccoli, cauliflower, beetroot, sweet pepper, tomato, chard, and red-cabbage juices suppressed IQ genotoxicity only moderately, whereas cucumber juice was ineffective. In most cases, fruits and vegetables inhibited PhIP genotoxicity less strongly than IQ genotoxicity. As one possible mechanism of antigenotoxicity, the inhibition of activating enzymes was studied either indirectly with diagnostic substrates or directly by measuring CYP1A2 inhibition. Only sour cherry, blueberry, and black currant juices suppressed the first step of HAA enzymatic activation, whereas most plant-derived beverages inhibited the second step. 2010 Elsevier B.V. All rights reserved.

Genotoxic effect of Physalis angulata L. (Solanaceae) extract on human lymphocytes treated in vitro.

PubMed

Alves dos Santos, Raquel; Cabral, Teresinha Rosa; Cabral, Isabel Rosa; Antunes, Lusânia Maria; Pontes Andrade, Cristiane; Cerqueira dos Santos Cardoso, Plínio; de Oliveira Bahia, Marcelo; Pessoa, Claudia; Martins do Nascimento, José Luis; Rodríguez Burbano, Rommel; Takahashi, Catarina Satie

2008-08-01

Physalis angulata L (Solanaceae) is a medicinal plant from North of Brazil, whose different extracts and infusions are commonly used in the popular medicine for the treatment of malaria, asthma, hepatitis, dermatitis and rheumatism. However, the genotoxic effects of P. angulata on human cells is not well known. The main purpose of the present study was to evaluate the in vitro genotoxic effects of aqueous extract of P. angulata using the comet assay and the micronucleus assay in human lymphocytes provided from 6 healthy donors. Treatments with P. angulata extracts were performed in vitro in order to access the extent of DNA damage. The comet assay has shown that treatments with P. angulata at 0.5, 1.0, 2.0, 3.0 and 6.0 microg/mL in culture medium were genotoxic. Lymphocytes treated with P. angulata at the concentrations of 3.0 and 6.0 microg/mL in culture medium showed a statistically significant increase in the frequency of micronucleus (p<0.05), however, the cytokinesis blocked proliferation index (CBPI) was not decreased after P. angulata treatment. In conclusion, the present work demonstrated the genotoxic effects of P. angulata extract on human lymphocytes in vitro.

Genotoxic and cytotoxic effects of doxorubicin and silymarin on human hepatocellular carcinoma cells.

PubMed

Yurtcu, E; İşeri, Öd; Sahin, Fi

2014-12-01

The aim of this study was to investigate genotoxic and cytotoxic effects of doxorubicin, silymarin, or in combination on HepG2 cells for 24 and 48 h. Both doxorubicin and silymarin caused dose-dependent inhibition of cell proliferation. After 48 h of treatment, doxorubicin application caused dramatically increased ratio of apoptotic cells. Both 24 and 48 h of silymarin and doxorubicin-silymarin combination caused significant increases in the rate of apoptotic cells. Applications of doxorubicin and silymarin separately for 24 h led to deoxyribonucleic acid (DNA) damages. After 48 h of incubation, doxorubicin-induced genotoxic damage was 2-fold higher than the silymarin-induced damage. After 24 and 48 h, DNA damage in response to combined applications of doxorubicin and silymarin was indifferent from silymarin- and doxorubicin-induced damage respectively. There was not any difference in genotoxicity levels between incubation periods in combined applications of doxorubicin and silymarin. Lipid peroxidation levels increased in all applications. Biopharmacotherapy with chemotherapeutic agents are of interest in the issue of adjuvant therapy. Here, we demonstrate in vitro potential genotoxic and cytotoxic antitumor effect of silymarin on HepG2 cells at achievable plasma level concentrations. © The Author(s) 2014.

Study of serum interaction with a cationic nanoparticle: Implications for in vitro endocytosis, cytotoxicity and genotoxicity.

PubMed

Merhi, Maysaloun; Dombu, Christophe Youta; Brient, Alizée; Chang, Jiang; Platel, Anne; Le Curieux, Frank; Marzin, Daniel; Nesslany, Fabrice; Betbeder, Didier

2012-02-14

We used well-characterized and positively charged nanoparticles (NP(+)) to investigate the importance of cell culture conditions, specifically the presence of serum and proteins, on NP(+) physicochemical characteristics, and the consequences for their endocytosis and genotoxicity in bronchial epithelial cells (16HBE14o-). NP(+) surface charge was significantly reduced, proportionally to NP(+)/serum and NP(+)/BSA ratios, while NP(+) size was not modified. Microscopy studies showed high endocytosis of NP(+) in 16HBE14o-, and serum/proteins impaired this internalization in a dose-dependent manner. Toxicity studies showed no cytotoxicity, even for very high doses of NP(+). No genotoxicity was observed with classic comet assay while primary oxidative DNA damage was observed when using the lesion-specific repair enzyme, formamidopyrimidine DNA-glycosylase (FPG). The micronucleus test showed NP(+) genotoxicity only for very high doses that cannot be attained in vivo. The low toxicity of these NP(+) might be explained by their high exocytosis from 16HBE14o- cells. Our results confirm the importance of serum and proteins on nanoparticles endocytosis and genotoxicity. Copyright © 2011 Elsevier B.V. All rights reserved.

Evaluation of genotoxic potential of avarol, avarone, and its methoxy and methylamino derivatives in prokaryotic and eukaryotic test models.

PubMed

Kolarević, Stoimir; Milovanović, Dragana; Kračun-Kolarević, Margareta; Kostić, Jovana; Sunjog, Karolina; Martinović, Rajko; Đorđević, Jelena; Novaković, Irena; Sladić, Dušan; Vuković-Gačić, Branka

2018-01-04

In this study, mutagenic and genotoxic potential of anti-tumor compounds avarol, avarone, and its derivatives 3'-methoxyavarone, 4'-(methylamino)avarone and 3'-(methylamino)avarone was evaluated and compared to cytostatics commonly used in chemotherapy (5-fluorouracil, etoposid, and cisplatin). Mutagenic potential of selected hydroquinone and quinones was assessed in prokaryotic model by the SOS/umuC assay in Salmonella typhimurium TA1535/pSK1002. Genotoxic potential was also assessed in eukaryotic models using comet assay in human fetal lung cell line (MRC-5), human adenocarcinoma epithelial cell line (A549), and in human peripheral blood cells (HPBC). The results indicated that avarol and avarone do not exert mutagenic/genotoxic potential. Among the studied avarone derivatives, mutagenic potential was detected by SOS/umuC test for 3'-(methylamino)avarone, but only after metabolic activation. The results of comet assay indicated that 3'-methoxyavarone and 3'-(methylamino)avarone have a significant impact on the level of DNA damage in the MRC-5 cell line. Genotoxic potential was not observed in A549 cells or HPBC probably due to a different uptake rate for the compounds and lower in metabolism rate within these cells.

Contributions of flumequine and nitroarenes to the genotoxicity of river and ground waters.

PubMed

Ma, Fujun; Yuan, Guanxiang; Meng, Liping; Oda, Yoshimitsu; Hu, Jianying

2012-07-01

The SOS/umuC assay was performed in conjunction with analytical measurements to identify potential genotoxins in river and adjacent ground waters in the Jialu River basin, China. The major genotoxic activities of the river and adjacent ground waters occurred in the same two fractions (F4 and F11) when assayed using the Salmonella typhimurium strain TA1535/pSK1002. This indicates that ground water near the Jialu River was influenced by the river water. LC-MS/MS analysis indicated that flumequine accounted for 86% and 76% of the genotoxicity in fraction F11 of the river and adjacent ground waters, respectively. When HPLC fractions were tested using the strain NM3009, three fractions showed genotoxic activities for river water sample, while no fractions from ground water samples elicited genotoxic activities. The specific response to the strain NM3009 in one fraction compared with the strain TA1535/pSK1002 suggested the presence of nitroarenes. However, we failed to identify the exact nitroarenes when GC-MS analysis was used to analyze nitroarenes which are well detected in air and soil samples in previous papers. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genotoxicity induced by Taenia solium and its reduction by immunization with calreticulin in a hamster model of taeniosis.

PubMed

Salazar, Ana María; Mendlovic, Fela; Cruz-Rivera, Mayra; Chávez-Talavera, Oscar; Sordo, Monserrat; Avila, Guillermina; Flisser, Ana; Ostrosky-Wegman, Patricia

2013-06-01

Genotoxicity induced by neurocysticercosis has been demonstrated in vitro and in vivo in humans. The adult stage of Taenia solium lodges in the small intestine and is the main risk factor to acquire neurocysticercosis, nevertheless its carcinogenic potential has not been evaluated. In this study, we determined the genotoxic effect of T. solium infection in the hamster model of taeniosis. In addition, we assessed the effect of oral immunization with recombinant T. solium calreticulin (rTsCRT) plus cholera toxin as adjuvant on micronuclei induction, as this protein has been shown to induce 33-44% protection in the hamster model of taeniosis. Blood samples were collected from the orbital venous plexus of noninfected and infected hamsters at different days postinfection, as well as from orally immunized animals, to evaluate the frequency of micronucleated reticulocytes as a measure of genotoxicity induced by parasite exposure and rTsCRT vaccination. Our results indicate that infection with T. solium caused time-dependent DNA damage in vivo and that rTsCRT immunization reduced the genotoxic damage induced by the presence of the tapeworms. Copyright © 2013 Wiley Periodicals, Inc.

Considering mutagenicity and genotoxicity in the cancer mode ...

EPA Pesticide Factsheets

It is well known that genotoxicity plays a significant role in the development of tumor formation. Mutations in somatic cells can play a key role early in cancer initiation and might affect other stages of the carcinogenic process. Determination of carcinogens that operate through a genotoxic mode of action entails evaluation of the available data. One way of determining if a chemical is acting through a genotoxic mechanism is to assemble the relevant data (human, animal, in vivo, in vitro) of individual genetic end points, evaluating the data against a current acceptance criteria (study quality, methodology used etc.), and determining the weight of evidence based on both the available data as well as evaluating against other existing information such as epidemiological data, ADME information etc. This presentation will lay-out key, currently available genotoxicity information on naphthalene, styrene and ethylbenzene. These three chemicals were chosen because all three chemicals cause mouse lung tumors, in particular bronchiolar-alveolar adenomas and carcinomas. This analysis of the data will enable further understanding of the mode of action of mouse lung tumor formation and species differences, which will impact the hazard identification and use of mode of action in the risk assessment of naphthalene, styrene, and ethylbenzene.

Recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests: a follow-up to an ECVAM workshop.

PubMed

Kirkland, David; Kasper, Peter; Müller, Lutz; Corvi, Raffaella; Speit, Günter

2008-05-31

At a recent ECVAM workshop considering ways to reduce the frequency of irrelevant positive results in mammalian cell genotoxicity tests [D. Kirkland, S. Pfuhler, D. Tweats, M. Aardema, R. Corvi, F. Darroudi, A. Elhajouji, H.-R. Glatt, P. Hastwell, M. Hayashi, P. Kasper, S. Kirchner, A. Lynch, D. Marzin, D. Maurici, J.-R. Meunier, L. Müller, G. Nohynek, J. Parry, E. Parry, V. Thybaud, R. Tice, J. van Benthem, P. Vanparys, P. White, How to reduce false positive results when undertaking in vitro genotoxicity testing and thus avoid unnecessary followup animal tests: Report of an ECVAM Workshop, Mutat. Res. 628 (2007) 31-55], recommendations for improvements/modifications to existing tests, and suggestions for new assays were made. Following on from this, it was important to identify chemicals that could be used in the evaluation of modified or new assays. An expert panel was therefore convened and recommendations made for chemicals to fit three different sets of characteristics, namely: This paper therefore contains these three recommended lists of chemicals and describes how these should be used for any test-evaluation programme.

The current limitations of in vitro genotoxicity testing and their relevance to the in vivo situation.

PubMed

Nesslany, Fabrice

2017-08-01

The standard regulatory core battery of genotoxicity tests generally includes 2 or 3 validated tests with at least one in vitro test in bacteria and one in vitro test on cell cultures. However, limitations in in vitro genotoxicity testing may exist at many levels. The knowledge of the underlying mechanisms of genotoxicity is particularly useful to assess the level of relevance for the in vivo situation. In order to avoid wrong conclusions regarding the actual genotoxicity status of any test substance, it appears very important to be aware of the various origins of related bias leading to 'false positives and negatives' by using in vitro methods. Among these, mention may be made on the metabolic activation system, experimental (extreme) conditions, specificities of the test systems implemented, cell type used etc. The knowledge of the actual 'limits' of the in vitro test systems used is clearly an advantage and may contribute to avoid some pitfalls in order to better assess the level of relevance for the in vivo situation. Copyright © 2016. Published by Elsevier Ltd.

The Vitotox and ToxTracker assays: A two-test combination for quick and reliable assessment of genotoxic hazards.

PubMed

Ates, Gamze; Favyts, Dorien; Hendriks, Giel; Derr, Remco; Mertens, Birgit; Verschaeve, Luc; Rogiers, Vera; Y Doktorova, Tatyana

2016-11-01

To ensure safety for humans, it is essential to characterize the genotoxic potential of new chemical entities, such as pharmaceutical and cosmetic substances. In a first tier, a battery of in vitro tests is recommended by international regulatory agencies. However, these tests suffer from inadequate specificity: compounds may be wrongly categorized as genotoxic, resulting in unnecessary, time-consuming, and expensive in vivo follow-up testing. In the last decade, novel assays (notably, reporter-based assays) have been developed in an attempt to overcome these drawbacks. Here, we have investigated the performance of two in vitro reporter-based assays, Vitotox and ToxTracker. A set of reference compounds was selected to span a variety of mechanisms of genotoxic action and applicability domains (e.g., pharmaceutical and cosmetic ingredients). Combining the performance of the two assays, we achieved 93% sensitivity and 79% specificity for prediction of gentoxicity for this set of compounds. Both assays permit quick high-throughput analysis of drug candidates, while requiring only small quantities of the test substances. Our study shows that these two assays, when combined, can be a reliable method for assessment of genotoxicity hazard. Copyright © 2016 Elsevier B.V. All rights reserved.

Lack of genotoxicity in medical oncology nurses handling antineoplastic drugs: effect of work environment and protective equipment.

PubMed

Gulten, Tuna; Evke, Elif; Ercan, Ilker; Evrensel, Turkkan; Kurt, Ender; Manavoglu, Osman

2011-01-01

In this study we aimed to investigate the genotoxic effects of antineoplastic agents in occupationally exposed oncology nurses. Genotoxic effects mean the disruptive effects in the integrity of DNA and they are associated with cancer development. Biomonitoring of health care workers handling antineoplastic agents is helpful for the evaluation of exposure to cytostatics. The study included an exposed and two control groups. The exposed group (n=9) was comprised of oncology nurses. The first (n=9) and second (n=10) control groups were comprised of subjects who did not come into contact with antineoplastic drugs working respectively in the same department with oncology nurses and in different departments. Genotoxicity evaluation was performed using SCE analysis. After applying culture, harvest and chromosome staining procedures, a total of 25 metaphases were analyzed per person. Kruskal Wallis test was used to perform statistical analysis. A statistically significant difference of sister chromatid exchange frequencies was not observed between the exposed and control groups. Lack of genotoxicity in medical oncology nurses might be due to good working conditions with high standards of technical equipment and improved personal protection.

Potential genotoxic effects of melted snow from an urban area revealed by the Allium cepa test.

PubMed

Blagojević, Jelena; Stamenković, Gorana; Vujosević, Mladen

2009-09-01

The presence of well-known atmospheric pollutants is regularly screened for in large towns but knowledge about the effects of mixtures of different pollutants and especially their genotoxic potential is largely missing. Since falling snow collects pollutants from the air, melted snow samples could be suitable for evaluating potential genotoxicity. For this purpose the Allium cepa anaphase-telophase test was used to analyse melted snow samples from Belgrade, the capital city of Serbia. Samples of snow were taken at two sites, characterized by differences in pollution intensity, in three successive years. At the more polluted site the analyses showed a very high degree of both toxicity and genotoxicity in the first year of the study corresponding to the effects of the known mutagen used as the positive control. At the other site the situation was much better but not without warning signals. The results showed that standard analyses for the presence of certain contaminants in the air do not give an accurate picture of the possible consequences of urban air pollution because the genotoxic potential remains hidden. The A. cepa test has been demonstrated to be very convenient for evaluation of air pollution through analyses of melted snow samples.

Involvement of BDNF/TrkB and ERK/CREB axes in nitroglycerin-induced rat migraine and effects of estrogen on these signals in the migraine

PubMed Central

Guo, Jiu-Qing; Deng, Hui-Hui; Bo, Xiao

2017-01-01

ABSTRACT Migraine is a highly prevalent headache disorder, especially in women. Brain-derived neurotrophic factor (BDNF) and its receptor tropomyosin receptor kinases (TrkB), as well as extracellular signal-regulated kinase (ERK) and its downstream target c-AMP-responsive element binding protein (CREB) are strongly associated with the transmission of nociceptive information. However, the involvement of these substances in migraine has rarely been examined. In the present study, intraperitoneal injection of nitroglycerin (NTC) successfully induced rat migraine attack, as evidenced by behavioral testing. The location and abundance of these substances in the migraine model were determined by immunohistochemistry, real-time polymerase chain reaction (RT-PCR), western blot and enzyme-linked immunosorbant assays (ELISA). Results showed that BDNF, TrkB, phosphor(p)-ERK and p-CREB were up-regulated in the brain neurons of both male and female rats with NTG-induced migraine compared to non-migraine control, whereas their expression levels were decreased in headache-free intervals of the migraine compared to migraine attacks. Estrogen is an important contributor to migraine. Female ovariectomized rats showed significant reduction in the expression of BDNF, TrkB, p-CREB and p-ERK in both attacks and intervals of NTG-induced migraine, relative to rats that have their ovaries. But, intraperitoneal administration of exogenous estrogen recovered their expression in ovariectomized rats. Collectively, this study unveiled a positive correlation of BDNF/TrkB and ERK/CREB axes in NTG-induced migraine and promoting effects of estrogen on their signals in the migraine. These findings contribute to further understanding the pathogenesis of migraine in the molecular basis. PMID:27875242

Induced jasmonate signaling leads to contrasting effects on root damage and herbivore performance.

PubMed

Lu, Jing; Robert, Christelle Aurélie Maud; Riemann, Michael; Cosme, Marco; Mène-Saffrané, Laurent; Massana, Josep; Stout, Michael Joseph; Lou, Yonggen; Gershenzon, Jonathan; Erb, Matthias

2015-03-01

Induced defenses play a key role in plant resistance against leaf feeders. However, very little is known about the signals that are involved in defending plants against root feeders and how they are influenced by abiotic factors. We investigated these aspects for the interaction between rice (Oryza sativa) and two root-feeding insects: the generalist cucumber beetle (Diabrotica balteata) and the more specialized rice water weevil (Lissorhoptrus oryzophilus). Rice plants responded to root attack by increasing the production of jasmonic acid (JA) and abscisic acid, whereas in contrast to in herbivore-attacked leaves, salicylic acid and ethylene levels remained unchanged. The JA response was decoupled from flooding and remained constant over different soil moisture levels. Exogenous application of methyl JA to the roots markedly decreased the performance of both root herbivores, whereas abscisic acid and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid did not have any effect. JA-deficient antisense 13-lipoxygenase (asLOX) and mutant allene oxide cyclase hebiba plants lost more root biomass under attack from both root herbivores. Surprisingly, herbivore weight gain was decreased markedly in asLOX but not hebiba mutant plants, despite the higher root biomass removal. This effect was correlated with a herbivore-induced reduction of sucrose pools in asLOX roots. Taken together, our experiments show that jasmonates are induced signals that protect rice roots from herbivores under varying abiotic conditions and that boosting jasmonate responses can strongly enhance rice resistance against root pests. Furthermore, we show that a rice 13-lipoxygenase regulates root primary metabolites and specifically improves root herbivore growth. © 2015 American Society of Plant Biologists. All Rights Reserved.

Genetic toxicology of abused drugs: a brief review.

PubMed

Li, J H; Lin, L F

1998-11-01

Although numerous studies have been conducted on abused drugs, most focus on the problems of addiction (dependence) and their neurotoxicities. Now accumulated data have demonstrated that the genotoxicity and/or carcinogenicity of abused drugs can also be detrimental to our health. In this review, commonly abused substances, including LSD, opiates (diacetylmorphine, morphine, opium and codeine), cocaine, cannabis, betel quid and khat, are discussed for their potential genotoxicity/carcinogenicity. The available literature in the field, although not as abundant as for neurotoxicity, clearly indicates the capability of abused drugs to induce genotoxicity.

Chlorination of tramadol: Reaction kinetics, mechanism and genotoxicity evaluation.

PubMed

Cheng, Hanyang; Song, Dean; Chang, Yangyang; Liu, Huijuan; Qu, Jiuhui

2015-12-01

Tramadol (TRA) is one of the most detected analgesics in environmental matrices, and it is of high significance to study the reactivity of TRA during chlorination considering its potential toxicity to the environment. The chlorine/TRA reaction is first order with respect to the TRA concentration, and a combination of first-order and second-order with respect to chlorine concentration. The pH dependence of the observed rate constants (kobs) showed that the TRA oxidation reactivity increased with increasing pH. kobs can be quantitatively described by considering all active species including Cl2, Cl2O and HOCl, and the individual rate constants of HOCl/TRA(0), HOCl/TRAH(+), Cl2/TRA and Cl2O/TRA reactions were calculated to be (2.61±0.29)×10(3)M(-1)s(-1), 14.73±4.17M(-1)s(-1), (3.93±0.34)×10(5)M(-1)s(-1) and (5.66±1.83)×10(6)M(-1)s(-1), respectively. Eleven degradation products were detected with UPLC-Q-TOF-MS, and the corresponding structures of eight products found under various pH conditions were proposed. The amine group was proposed to be the initial attack site under alkaline pH conditions, where reaction of the deprotonated amine group with HOCl is favorable. Under acidic and neutral pH conditions, however, two possible reaction pathways were proposed. One is an electrophilic substitution on the aromatic ring, and another is an electrophilic substitution on the nitrogen, leading to an N-chlorinated intermediate, which can be further oxidized. Finally, the SOS/umu test showed that the genotoxicity of TRA chlorination products increased with increasing dosage of chlorine, which was mostly attributed to the formation of some chlorine substitution products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Protection by beverages, fruits, vegetables, herbs, and flavonoids against genotoxicity of 2-acetylaminofluorene and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in metabolically competent V79 cells.

PubMed

Edenharder, R; Sager, J W; Glatt, H; Muckel, E; Platt, K L

2002-11-26

Chinese hamster lung fibroblasts, genetically engineered for the expression of rat cytochrome P450 dependent monooxygenase 1A2 and rat sulfotransferase 1C1 (V79-rCYP1A2-rSULT1C1 cells), were utilized to check for possible protective effects of beverages of plant origin, fruits, vegetables, and spices against genotoxicity induced by 2-acetylaminofluorene (AAF) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Antigenotoxic activities of juices from spinach and red beets against AAF could be monitored with similar effectivity by the HPRT-mutagenicity test (IC(50)=0.64%; 2.57%) and alkaline single cell gel electrophoresis (comet assay; IC(50)=0.12%; 0.89%) which detects DNA strand breaks and abasic sites. Applying the comet assay, genotoxicity of PhIP could, however, be demonstrated only in the presence of hydroxyurea and 1-[beta-D-arabinofuranosyl]cytosine, known inhibitors of DNA repair synthesis. As expected, AAF and PhIP were unable to induce any genotoxic effects in the parent V79 cells. Genotoxic activity of PhIP was strongly reduced in a dose-related manner by green tea and red wine, by blueberries, blackberries, red grapes, kiwi, watermelon, parsley, and spinach, while two brands of beer, coffee, black tea, rooibos tea, morellos, black-currants, plums, red beets, broccoli (raw and cooked), and chives were somewhat less active. One brand of beer was only moderately active while white wine, bananas, white grapes, and strawberries were inactive. Similarly, genotoxicity of AAF was strongly reduced by green, black, and rooibos tea, red wine, morellos, black-currants, kiwi, watermelon, and spinach while plums, red beets, and broccoli (raw) were less potent. Broccoli cooked exerted only moderate and white wine weak antigenotoxic activity. With respect to the possible mechanism(s) of inhibition of genotoxicity, benzo[a]pyrene-7,8-dihydrodiol (BaP-7,8-OH) and N-OH-PhIP were applied as substrates for the CYP1A family and for rSULT 1C1, respectively. Morellos, black-currants, and black tea strongly reduced the genotoxicity of BaP-7,8-OH, onions, rooibos tea, and red wine were less potent while red beets and spinach were inactive. On the other hand, red beets and spinach strongly inhibited the genotoxicity of N-OH-PhIP, rooibos tea was weakly active while all other items were inactive. These results are suggestive for enzyme inhibition as mechanism of protection by complex mixtures of plant origin. Taken together, our results demonstrate that protection by beverages, fruits, and vegetables against genotoxicity of heterocyclic aromatic amines may take place within metabolically competent mammalian cells as well as under the conditions of the Salmonella/reversion assay.

Genotoxicity assessment of raw and treated water samples using Allium cepa assay: evidence from Perak River, Malaysia.

PubMed

Malakahmad, Amirhossein; Manan, Teh Sabariah Binti Abd; Sivapalan, Subarna; Khan, Taimur

2018-02-01

Allium cepa assay was carried out in this study to evaluate genotoxic effects of raw and treated water samples from Perak River in Perak state, Malaysia. Samples were collected from three surface water treatment plants along the river, namely WTPP, WTPS, and WTPK. Initially, triplicates of equal size Allium cepa (onions) bulbs, 25-30 mm in diameter and average weight of 20 g, were set up in distilled water for 24 h at 20 ± 2 °C and protected from direct sunlight, to let the roots to grow. After germination of roots (0.5-1.0 cm in length), bulbs were transferred to collected water samples each for a 96-h period of exposure. The root physical deformations were observed. Genotoxicity quantification was based on mitotic index and genotoxicity level. Statistical analysis using cross-correlation function for replicates from treated water showed that root length has inverse correlation with mitotic indices (r = - 0.969) and frequencies of cell aberrations (r = - 0.976) at lag 1. Mitotic indices and cell aberrations of replicates from raw water have shown positive correlation at lag 1 (r = 0.946). Genotoxicity levels obtained were 23.4 ± 1.98 (WTPP), 26.68 ± 0.34 (WTPS), and 30.4 ± 1.13 (WTPK) for treated water and 17.8 ± 0.18 (WTPP), 37.15 ± 0.17 (WTPS), and 47.2 ± 0.48 (WTPK) for raw water. The observed cell aberrations were adherence, chromosome delay, C-metaphase, chromosome loss, chromosome bridge, chromosome breaks, binucleated cell, mini cell, and lobulated nuclei. The morphogenetic deformations obtained were likely due to genotoxic substances presence in collected water samples. Thus, water treatment in Malaysia does not remove genotoxic compounds.

Genotoxicity of metal oxide nanomaterials: review of recent data and discussion of possible mechanisms

NASA Astrophysics Data System (ADS)

Golbamaki, Nazanin; Rasulev, Bakhtiyor; Cassano, Antonio; Marchese Robinson, Richard L.; Benfenati, Emilio; Leszczynski, Jerzy; Cronin, Mark T. D.

2015-01-01

Nanotechnology has rapidly entered into human society, revolutionized many areas, including technology, medicine and cosmetics. This progress is due to the many valuable and unique properties that nanomaterials possess. In turn, these properties might become an issue of concern when considering potentially uncontrolled release to the environment. The rapid development of new nanomaterials thus raises questions about their impact on the environment and human health. This review focuses on the potential of nanomaterials to cause genotoxicity and summarizes recent genotoxicity studies on metal oxide/silica nanomaterials. Though the number of genotoxicity studies on metal oxide/silica nanomaterials is still limited, this endpoint has recently received more attention for nanomaterials, and the number of related publications has increased. An analysis of these peer reviewed publications over nearly two decades shows that the test most employed to evaluate the genotoxicity of these nanomaterials is the comet assay, followed by micronucleus, Ames and chromosome aberration tests. Based on the data studied, we concluded that in the majority of the publications analysed in this review, the metal oxide (or silica) nanoparticles of the same core chemical composition did not show different genotoxicity study calls (i.e. positive or negative) in the same test, although some results are inconsistent and need to be confirmed by additional experiments. Where the results are conflicting, it may be due to the following reasons: (1) variation in size of the nanoparticles; (2) variations in size distribution; (3) various purities of nanomaterials; (4) variation in surface areas for nanomaterials with the same average size; (5) differences in coatings; (6) differences in crystal structures of the same types of nanomaterials; (7) differences in size of aggregates in solution/media; (8) differences in assays; (9) different concentrations of nanomaterials in assay tests. Indeed, due to the observed inconsistencies in the recent literature and the lack of adherence to appropriate, standardized test methods, reliable genotoxicity assessment of nanomaterials is still challenging.

TRAF Family Member-associated NF-κB Activator (TANK) Inhibits Genotoxic Nuclear Factor κB Activation by Facilitating Deubiquitinase USP10-dependent Deubiquitination of TRAF6 Ligase.

PubMed

Wang, Wei; Huang, Xuan; Xin, Hong-Bo; Fu, Mingui; Xue, Aimin; Wu, Zhao-Hui

2015-05-22

DNA damage-induced NF-κB activation plays a critical role in regulating cellular response to genotoxic stress. However, the molecular mechanisms controlling the magnitude and duration of this genotoxic NF-κB signaling cascade are poorly understood. We recently demonstrated that genotoxic NF-κB activation is regulated by reversible ubiquitination of several essential mediators involved in this signaling pathway. Here we show that TRAF family member-associated NF-κB activator (TANK) negatively regulates NF-κB activation by DNA damage via inhibiting ubiquitination of TRAF6. Despite the lack of a deubiquitination enzyme domain, TANK has been shown to negatively regulate the ubiquitination of TRAF proteins. We found TANK formed a complex with MCPIP1 (also known as ZC3H12A) and a deubiquitinase, USP10, which was essential for the USP10-dependent deubiquitination of TRAF6 and the resolution of genotoxic NF-κB activation upon DNA damage. Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated deletion of TANK in human cells significantly enhanced NF-κB activation by genotoxic treatment, resulting in enhanced cell survival and increased inflammatory cytokine production. Furthermore, we found that the TANK-MCPIP1-USP10 complex also decreased TRAF6 ubiquitination in cells treated with IL-1β or LPS. In accordance, depletion of USP10 enhanced NF-κB activation induced by IL-1β or LPS. Collectively, our data demonstrate that TANK serves as an important negative regulator of NF-κB signaling cascades induced by genotoxic stress and IL-1R/Toll-like receptor stimulation in a manner dependent on MCPIP1/USP10-mediated TRAF6 deubiquitination. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Comet assay evaluation of six chemicals of known genotoxic potential in rats.

PubMed

Hobbs, Cheryl A; Recio, Leslie; Streicker, Michael; Boyle, Molly H; Tanaka, Jin; Shiga, Atsushi; Witt, Kristine L

2015-07-01

As a part of an international validation of the in vivo rat alkaline comet assay (comet assay) initiated by the Japanese Center for the Validation of Alternative Methods (JaCVAM) we examined six chemicals for potential to induce DNA damage: 2-acetylaminofluorene (2-AAF), N-nitrosodimethylamine (DMN), o-anisidine, 1,2-dimethylhydrazine dihydrochloride (1,2-DMH), sodium chloride, and sodium arsenite. DNA damage was evaluated in the liver and stomach of 7- to 9-week-old male Sprague Dawley rats. Of the five genotoxic carcinogens tested in our laboratory, DMN and 1,2-DMH were positive in the liver and negative in the stomach, 2-AAF and o-anisidine produced an equivocal result in liver and negative results in stomach, and sodium arsenite was negative in both liver and stomach. 1,2-DMH and DMN induced dose-related increases in hedgehogs in the same tissue (liver) that exhibited increased DNA migration. However, no cytotoxicity was indicated by the neutral diffusion assay (assessment of highly fragmented DNA) or histopathology in response to treatment with any of the tested chemicals. Therefore, the increased DNA damage resulting from exposure to DMN and 1,2-DMH was considered to represent a genotoxic response. Sodium chloride, a non-genotoxic non-carcinogen, was negative in both tissues as would be predicted. Although only two (1,2-DMH and DMN) out of five genotoxic carcinogens produced clearly positive results in the comet assay, the results obtained for o-anisidine and sodium arsenite in liver and stomach cells are consistent with the known mode of genotoxicity and tissue specificity exhibited by these carcinogens. In contrast, given the known genotoxic mode-of-action and target organ carcinogenicity of 2-AAF, it is unclear why this chemical failed to convincingly increase DNA migration in the liver. Thus, the results of the comet assay validation studies conducted in our laboratory were considered appropriate for five out of the six test chemicals. Copyright © 2015 Elsevier B.V. All rights reserved.

Genotoxic effects of environmental endocrine disruptors on the aquatic insect Chironomus riparius evaluated using the comet assay.

PubMed

Martínez-Paz, Pedro; Morales, Mónica; Martínez-Guitarte, José Luis; Morcillo, Gloria

2013-12-12

Genotoxicity is one of the most important toxic endpoints in chemical toxicity testing and environmental risk assessment. The aim of this study was to evaluate the genotoxic potential of various environmental pollutants frequently found in aquatic environments and characterized by their endocrine disrupting activity. Monitoring of DNA damage was undertaken after in vivo exposures of the aquatic larvae of the midge Chironomus riparius, a model organism that represents an abundant and ecologically relevant macroinvertebrate, widely used in freshwater toxicology. DNA-induced damage, resulting in DNA fragmentation, was quantified by the comet assay after short (24 h) and long (96 h) exposures to different concentrations of the selected toxicants: bisphenol A (BPA), nonylphenol (NP), pentachlorophenol (PCP), tributyltin (TBT) and triclosan (TCS). All five compounds were found to have genotoxic activity as demonstrated by significant increases in all the comet parameters (%DNA in tail, tail length, tail moment and Olive tail moment) at all tested concentrations. Persistent exposure did not increase the extent of DNA damage, except for TCS at the highest concentration, but generally there was a reduction in DNA damage thought to be associated with the induction of the detoxification processes and repairing mechanisms. Comparative analysis showed differences in the genotoxic potential between the chemicals, as well as significant time and concentration-dependent variations, which most likely reflect differences in the ability to repair DNA damage under the different treatments. The present report demonstrates the sensitivity of the benthic larvae of C. riparius to these environmental genotoxins suggesting its potential as biomonitor organism in freshwater ecosystems. The results obtained about the DNA-damaging potential of these environmental pollutants reinforce the need for additional studies on the genotoxicity of endocrine active substances that, by linking genotoxic activity to other biological responses, could provide further understanding of adverse effects in aquatic environments. Copyright © 2013 Elsevier B.V. All rights reserved.

Early genotoxic response and accumulation induced by waterborne copper, lead, and arsenic in European seabass, Dicentrarchus labrax.

PubMed

Canalejo, Antonio; Diaz-de-Alba, Margarita; Granado-Castro, M Dolores; Cordoba, Francisco; Espada-Bellido, Estrella; Galindo-Riaño, M Dolores; Torronteras, Rafael

2016-02-01

Cu, Pb, and As, which are among the most abundant metals in the aquatic environment, are also among the most health-threatened by causing diverse cellular injuries. The aim of this study was to assess and compare the potential early induction of genotoxic effects after waterborne Cu, Pb, and As exposure in European seabass, Dicentrarchus labrax, a commercial widely cultured fish, using the micronucleus (MN) assay in peripheral blood erythrocytes. Fish were exposed under laboratory conditions to nominal solutions ranging 0-10 mg/L for 24 and 96 h. Furthermore, actual metal ion concentrations were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) or differential pulse anodic stripping voltammetry (DPASV) in water and four fish tissues differentially related to environmental exposition and metal accumulation, i.e. the gills, liver, muscle, and brain. Dose-dependent increases of micronuclei (MNi) frequency were observed after these very short exposures; based on measured metal concentrations in water, the genotoxic effect ordered as Cu > As > Pb. Significant genotoxic effect at 0.009 mg/L Cu, 0.57 mg/L Pb, and 0.01 mg/L As was seen. For Cu and Pb these are only slightly higher, but for As it is notably lower than the USEPA criteria of maximum concentration to prevent acute toxicity in aquatic organisms. Furthermore, genotoxicity was differentially related to metal accumulation. MNi frequency correlated positively with the content of Pb in all the organs, with the content of As in liver and gills and only with the content of Cu in the brain. In conclusion, our findings raised environmental concerns because these depicted a genotoxic potential of Cu, Pb, and As after a very short exposure to low but environmentally relevant concentrations, too close to regulatory thresholds. In addition, the MN test in D. labrax could be considered an early biomarker of genotoxicity induced by these metals in fish.

Updated recommended lists of genotoxic and non-genotoxic chemicals for assessment of the performance of new or improved genotoxicity tests.

PubMed

Kirkland, David; Kasper, Peter; Martus, Hans-Jörg; Müller, Lutz; van Benthem, Jan; Madia, Federica; Corvi, Raffaella

2016-01-01

In 2008 we published recommendations on chemicals that would be appropriate to evaluate the sensitivity and specificity of new/modified mammalian cell genotoxicity tests, in particular to avoid misleading positive results. In light of new data it is appropriate to update these lists of chemicals. An expert panel was convened and has revised the recommended chemicals to fit the following different sets of characteristics: • Group 1: chemicals that should be detected as positive in in vitro mammalian cell genotoxicity tests. Chemicals in this group are all in vivo genotoxins at one or more endpoints, either due to DNA-reactive or non DNA-reactive mechanisms. Many are known carcinogens with a mutagenic mode of action, but a sub-class of probable aneugens has been introduced. • Group 2: chemicals that should give negative results in in vitro mammalian cell genotoxicity tests. Chemicals in this group are usually negative in vivo and non-DNA-reactive. They are either non-carcinogenic or rodent carcinogens with a non-mutagenic mode of action. • Group 3: chemicals that should give negative results in in vitro mammalian cell genotoxicity tests, but have been reported to induce gene mutations in mouse lymphoma cells, chromosomal aberrations or micronuclei, often at high concentrations or at high levels of cytotoxicity. Chemicals in this group are generally negative in vivo and negative in the Ames test. They are either non-carcinogenic or rodent carcinogens with an accepted non-mutagenic mode of action. This group contains comments as to any conditions that can be identified under which misleading positive results are likely to occur. This paper, therefore, updates these three recommended lists of chemicals and describes how these should be used for any test evaluation program. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

A comparative genotoxicity study of a supraphysiological dose of triiodothyronine (T₃) in obese rats subjected to either calorie-restricted diet or hyperthyroidism.

PubMed

De Sibio, Maria Teresa; Luvizotto, Renata Azevedo Melo; Olimpio, Regiane Marques Castro; Corrêa, Camila Renata; Marino, Juliana; de Oliveira, Miriane; Conde, Sandro José; Ferreira, Ana Lúcia dos Anjos; Padovani, Carlos Roberto; Nogueira, Célia Regina

2013-01-01

This study was designed to determine the genotoxicity of a supraphysiological dose of triiodothyronine (T3) in both obese and calorie-restricted obese animals. Fifty male Wistar rats were randomly assigned to one of the two following groups: control (C; n = 10) and obese (OB; n = 40). The C group received standard food, whereas the OB group was fed a hypercaloric diet for 20 weeks. After this period, half of the OB animals (n = 20) were subjected to a 25%-calorie restriction of standard diet for 8 weeks forming thus a new group (OR), whereas the remaining OB animals were kept on the initial hypercaloric diet. During the following two weeks, 10 OR animals continued on the calorie restriction diet, whereas the remaining 10 rats of this group formed a new group (ORS) given a supraphysiological dose of T3 (25 µg/100 g body weight) along with the calorie restriction diet. Similarly, the remaining OB animals were divided into two groups, one that continued on the hypercaloric diet (OB, n = 10), and one that received the supraphysiological dose of T3 (25 µg/100 g body weight) along with the hypercaloric diet (OS, n = 10) for two weeks. The OB group showed weight gain, increased adiposity, insulin resistance, increased leptin levels and genotoxicity; T3 administration in OS animals led to an increase in genotoxicity and oxidative stress when compared with the OB group. The OR group showed weight loss and normalized levels of adiposity, insulin resistance, serum leptin and genotoxicity, thus having features similar to those of the C group. On the other hand, the ORS group, compared to OR animals, showed higher genotoxicity. Our results indicate that regardless of diet, a supraphysiological dose of T3 causes genotoxicity and potentiates oxidative stress.

A Comparative Genotoxicity Study of a Supraphysiological Dose of Triiodothyronine (T3) in Obese Rats Subjected to Either Calorie-Restricted Diet or Hyperthyroidism

PubMed Central

De Sibio, Maria Teresa; Luvizotto, Renata Azevedo Melo; Olimpio, Regiane Marques Castro; Corrêa, Camila Renata; Marino, Juliana; de Oliveira, Miriane; Conde, Sandro José; Ferreira, Ana Lúcia dos Anjos; Padovani, Carlos Roberto; Nogueira, Célia Regina

2013-01-01

This study was designed to determine the genotoxicity of a supraphysiological dose of triiodothyronine (T3) in both obese and calorie-restricted obese animals. Fifty male Wistar rats were randomly assigned to one of the two following groups: control (C; n = 10) and obese (OB; n = 40). The C group received standard food, whereas the OB group was fed a hypercaloric diet for 20 weeks. After this period, half of the OB animals (n = 20) were subjected to a 25%-calorie restriction of standard diet for 8 weeks forming thus a new group (OR), whereas the remaining OB animals were kept on the initial hypercaloric diet. During the following two weeks, 10 OR animals continued on the calorie restriction diet, whereas the remaining 10 rats of this group formed a new group (ORS) given a supraphysiological dose of T3 (25 µg/100 g body weight) along with the calorie restriction diet. Similarly, the remaining OB animals were divided into two groups, one that continued on the hypercaloric diet (OB, n = 10), and one that received the supraphysiological dose of T3 (25 µg/100 g body weight) along with the hypercaloric diet (OS, n = 10) for two weeks. The OB group showed weight gain, increased adiposity, insulin resistance, increased leptin levels and genotoxicity; T3 administration in OS animals led to an increase in genotoxicity and oxidative stress when compared with the OB group. The OR group showed weight loss and normalized levels of adiposity, insulin resistance, serum leptin and genotoxicity, thus having features similar to those of the C group. On the other hand, the ORS group, compared to OR animals, showed higher genotoxicity. Our results indicate that regardless of diet, a supraphysiological dose of T3 causes genotoxicity and potentiates oxidative stress. PMID:23468891

Comet assay in reconstructed 3D human epidermal skin models--investigation of intra- and inter-laboratory reproducibility with coded chemicals.

PubMed

Reus, Astrid A; Reisinger, Kerstin; Downs, Thomas R; Carr, Gregory J; Zeller, Andreas; Corvi, Raffaella; Krul, Cyrille A M; Pfuhler, Stefan

2013-11-01

Reconstructed 3D human epidermal skin models are being used increasingly for safety testing of chemicals. Based on EpiDerm™ tissues, an assay was developed in which the tissues were topically exposed to test chemicals for 3h followed by cell isolation and assessment of DNA damage using the comet assay. Inter-laboratory reproducibility of the 3D skin comet assay was initially demonstrated using two model genotoxic carcinogens, methyl methane sulfonate (MMS) and 4-nitroquinoline-n-oxide, and the results showed good concordance among three different laboratories and with in vivo data. In Phase 2 of the project, intra- and inter-laboratory reproducibility was investigated with five coded compounds with different genotoxicity liability tested at three different laboratories. For the genotoxic carcinogens MMS and N-ethyl-N-nitrosourea, all laboratories reported a dose-related and statistically significant increase (P < 0.05) in DNA damage in every experiment. For the genotoxic carcinogen, 2,4-diaminotoluene, the overall result from all laboratories showed a smaller, but significant genotoxic response (P < 0.05). For cyclohexanone (CHN) (non-genotoxic in vitro and in vivo, and non-carcinogenic), an increase compared to the solvent control acetone was observed only in one laboratory. However, the response was not dose related and CHN was judged negative overall, as was p-nitrophenol (p-NP) (genotoxic in vitro but not in vivo and non-carcinogenic), which was the only compound showing clear cytotoxic effects. For p-NP, significant DNA damage generally occurred only at doses that were substantially cytotoxic (>30% cell loss), and the overall response was comparable in all laboratories despite some differences in doses tested. The results of the collaborative study for the coded compounds were generally reproducible among the laboratories involved and intra-laboratory reproducibility was also good. These data indicate that the comet assay in EpiDerm™ skin models is a promising model for the safety assessment of compounds with a dermal route of exposure.

Comet assay evaluation of six chemicals of known genotoxic potential in rats

PubMed Central

Hobbs, Cheryl A.; Recio, Leslie; Streicker, Michael; Boyle, Molly H.; Tanaka, Jin; Shiga, Atsushi; Witt, Kristine L.

2015-01-01

As a part of an International validation of the in vivo rat alkaline comet assay (comet assay) initiated by the Japanese Center for the Validation of Alternative Methods (JaCVAM) we examined six chemicals for potential to induce DNA damage: 2-acetylaminofluorene (2-AAF), N-nitrosodimethylamine (DMN), o-anisidine, 1,2-dimethylhydrazine dihydrochloride (1,2-DMH), sodium chloride, and sodium arsenite. DNA damage was evaluated in the liver and stomach of 7- to 9-week-old male Sprague Dawley rats. Of the five genotoxic carcinogens tested in our laboratory, DMN and 1,2-DMH were positive in the liver and negative in the stomach, 2-AAF and o-anisidine produced an equivocal result in liver and negative results in stomach, and sodium arsenite was negative in both liver and stomach. 1,2-DMH and DMN induced dose-related increases in hedgehogs in the same tissue (liver) that exhibited increased DNA migration. However, no cytotoxicity was indicated by the neutral diffusion assay (assessment of highly fragmented DNA) or histopathology in response to treatment with any of the tested chemicals. Therefore, the increased DNA damage resulting from exposure to DMN and 1,2-DMH was considered to represent a genotoxic response. Sodium chloride, a non-genotoxic non-carcinogen, was negative in both tissues as would be predicted. Although only two (1,2-DMH and DMN) out of five genotoxic carcinogens produced clearly positive results in the comet assay, the results obtained for o-anisidine and sodium arsenite in liver and stomach cells are consistent with the known mode of genotoxicity and tissue specificity exhibited by these carcinogens. In contrast, given the known genotoxic mode-of-action and target organ carcinogenicity of 2-AAF, it is unclear why this chemical failed to convincingly increase DNA migration in the liver. Thus, the results of the comet assay validation studies conducted in our laboratory were considered appropriate for five out of the six test chemicals. PMID:26212309

Evaluation of cytotoxicity, genotoxicity and teratogenicity of marine sediments from Qingdao coastal areas using in vitro fish cell assay, comet assay and zebrafish embryo test.

PubMed

Yang, Fan; Zhang, Qianqian; Guo, Huarong; Zhang, Shicui

2010-10-01

Marine sediments are often a final sink for numerous anthropogenic contaminants and may impose serious effects on benthic organisms and ecosystem. An in vitro cell assay using a cell line derived from flounder gill (FG) cells, an in vitro comet assay in FG cells, and an in vitro zebrafish embryo assay were used to evaluate the in vitro cytotoxicity (measured by MTT reduction), genotoxicity and teratogenicity of crude sediment extracts of Li Cang (LC), Zhan Qiao (ZQ) and Olympic Sailing Center (OSC) from Qingdao coastal area. Sediments from the three sites displayed different cytotoxicity, genotoxicity and teratogenicity potencies; however, all three assays yielded similar LOECs (lowest observed effect concentration) for each site, suggesting that the assays were equally sensitive to and suitable for initial screening of the LOECs of marine sediments. The cytotoxicity, genotoxicity and teratogenicity for these three sampling sites were in the same order of LC>ZQ>OSC, indicating different degrees of contamination. Interestingly, trials with the three sediment extracts at the doses inducing a similar cytotoxicity as evaluated with MTT reduction did not produce similar genotoxicity and teratogenicity, with the genotoxic and teratogenic activities of LC and ZQ extracts being markedly higher than those of OSC sediments. These findings indicate that cytotoxicity does not form a fully equivalent toxicity index with that of genotoxicity and teratogenicity. Therefore, in order to assess the true toxic potential of marine sediments, all three assays should be performed. Analysis of 16 EPA (US Environmental Protection Agency) priority PAHs in these three sediment samples showed a clear correlation between PAH concentrations and sediment toxicities, with a higher PAH content corresponding to higher toxicity although PAHs are surely not the only cause. Copyright © 2010 Elsevier Ltd. All rights reserved.

From the Cover: An Investigation of the Genotoxicity and Interference of Gold Nanoparticles in Commonly Used In Vitro Mutagenicity and Genotoxicity Assays.

PubMed

George, Jiya M; Magogotya, Millicent; Vetten, Melissa A; Buys, Antoinette V; Gulumian, Mary

2017-03-01

The suitability of 4 in vitro assays, commonly used for mutagenicity and genotoxicity assessment, was investigated in relation to treatment with 14 nm citrate-stabilized gold nanoparticles (AuNPs). Specifically, the Ames test was conducted without metabolic activation, where no mutagenic effects were observed. High resolution transmission electron microscopy and Cytoviva dark-field image analysis showed that AuNPs did not enter the bacterial cells, thus confirming the unreliability of the Ames test for nanoparticle mutagenicity studies. In addition, the Chinese hamster ovary (CHO) cell line was used for Comet, Chromosome aberration and Micronucleus assays. CHO cells were treated with AuNPs for 20 h at 37 °C. Cytotoxicity was not detected by cell impedance studies even though AuNP uptake was confirmed using Cytoviva image analysis. The DNA damage was statistically significant in treated cells when assessed by the Comet assay. However, minimal and nonstatistically significant chromosomal DNA damage was observed using the chromosome aberration and micronucleus assays. In this study, we showed that false positive results obtained with Comet assay may have been due to the possibility of direct contact between the residual, intracellular AuNPs and DNA during the assay procedure. Therefore, the chromosome aberration and micronucleus assays are better suited to assess the genotoxic effects of nanoparticles due to low probability of such direct contact occurring. Genotoxic effect of 14 and 20 nm citrate-stabilized, as well as, 14 nm PCOOH AuNPs were also investigated using chromosome aberration and micronucleus assays. Based on our acceptance criteria for a positive genotoxic response, none of the AuNPs were found to be genotoxic in either of these assays. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Comet assay in reconstructed 3D human epidermal skin models—investigation of intra- and inter-laboratory reproducibility with coded chemicals

PubMed Central

Pfuhler, Stefan

2013-01-01

Reconstructed 3D human epidermal skin models are being used increasingly for safety testing of chemicals. Based on EpiDerm™ tissues, an assay was developed in which the tissues were topically exposed to test chemicals for 3h followed by cell isolation and assessment of DNA damage using the comet assay. Inter-laboratory reproducibility of the 3D skin comet assay was initially demonstrated using two model genotoxic carcinogens, methyl methane sulfonate (MMS) and 4-nitroquinoline-n-oxide, and the results showed good concordance among three different laboratories and with in vivo data. In Phase 2 of the project, intra- and inter-laboratory reproducibility was investigated with five coded compounds with different genotoxicity liability tested at three different laboratories. For the genotoxic carcinogens MMS and N-ethyl-N-nitrosourea, all laboratories reported a dose-related and statistically significant increase (P < 0.05) in DNA damage in every experiment. For the genotoxic carcinogen, 2,4-diaminotoluene, the overall result from all laboratories showed a smaller, but significant genotoxic response (P < 0.05). For cyclohexanone (CHN) (non-genotoxic in vitro and in vivo, and non-carcinogenic), an increase compared to the solvent control acetone was observed only in one laboratory. However, the response was not dose related and CHN was judged negative overall, as was p-nitrophenol (p-NP) (genotoxic in vitro but not in vivo and non-carcinogenic), which was the only compound showing clear cytotoxic effects. For p-NP, significant DNA damage generally occurred only at doses that were substantially cytotoxic (>30% cell loss), and the overall response was comparable in all laboratories despite some differences in doses tested. The results of the collaborative study for the coded compounds were generally reproducible among the laboratories involved and intra-laboratory reproducibility was also good. These data indicate that the comet assay in EpiDerm™ skin models is a promising model for the safety assessment of compounds with a dermal route of exposure. PMID:24150594

GENOTOXICITY RISK ASSESSMENT: A PROPOSED CLASSIFICATION STRATEGY

EPA Science Inventory

Recent advances in genetic toxicity (mutagenicity) testing methods and in approaches to performing risk assessment are prompting a renewed effort to harmonize genotoxicity risk assessment across the world. The US Environmental Protection Agency (EPA) first published Guidelines fo...

Genotoxicity Biomarkers Associated with Exposure to Traffic And Near-Road Atmospheres: A Review

EPA Science Inventory

Genotoxicity Biomarkers Associated with Exposure to Traffic And Near-Road Atmospheres: A Review Diesel and gasoline emissions, which are the primary components of traffic exhaust, are known or possible human carcinogens, re...

Moesin Is a Biomarker for the Assessment of Genotoxic Carcinogens in Mouse Lymphoma

PubMed Central

Lee, Yoen Jung; Choi, In-Kwon; Sheen, Yhun Yhong; Park, Sue Nie; Kwon, Ho Jeong

2012-01-01

1,2-Dibromoethane and glycidol are well known genotoxic carcinogens, which have been widely used in industry. To identify a specific biomarker for these carcinogens in cells, the cellular proteome of L5178Y mouse lymphoma cells treated with these compounds was analyzed by 2-dimensional gel electrophoresis (2-DE) and MALDI-TOF mass spectrometry (MS). Of 50 protein spots showing a greater than 1.5-fold increase or decrease in intensity compared to control cells on a 2-D gel, we focused on the candidate biomarker moesin. Western analysis using monoclonal rabbit anti-moesin confirmed the identity of the protein and its increased level of expression upon exposure to the carcinogenic compounds. Moesin expression also increased in cells treated with six additional genotoxic carcinogens, verifying that moesin could serve as a biomarker to monitor phenotypic change upon exposure to genotoxic carcinogens in L5178Y mouse lymphoma cells. PMID:22358511

In vitro genotoxic effects of four Helichrysum species in human lymphocytes cultures.

PubMed

Erolu, Erhan H; Hamzaolu, Ergin; Aksoy, Ahmet; Budak, Ümit; Özkul, Yusuf

2010-01-01

Helichrysum sanguineum, Helichrysum pamphylicum, Helichrysum orientale, Helichrysum noeanum (Asteraceae) are medicinal plants. For centuries, they have been used as tea in Turkey because of their medicinal properties. So far no scientific evidence has been found in a literature survey regarding the genotoxic effects of these plants. This work evaluated the genotoxic effects on human lymphocyte cultures induced by methanol extracts of these plants, assayed in different concentrations (0.01, 0.05, 0.1, 0.5 and 1 mg/mL). According to the results, Helichrysum noeanum, Helichrysum pamphylicum and Helichrysum sanguineum induced the formation of micronuclei and decreased the mitotic and replication indexes. Helichrysum orientale did not affect these parameters, whereas Helichrysum noeanum, Helichrysum pamphylicum and Helichrysum sanguineum were clearly genotoxic. They should therefore not be used freely in alternative medicine, although their antiproliferative activity may suggest antimitotic and anticarcinogenic properties. Helichrysum orientale could be used in alternative medicine.

Moesin is a biomarker for the assessment of genotoxic carcinogens in mouse lymphoma.

PubMed

Lee, Yoen Jung; Choi, In-Kwon; Sheen, Yhun Yhong; Park, Sue Nie; Kwon, Ho Jeong

2012-02-01

1,2-Dibromoethane and glycidol are well known genotoxic carcinogens, which have been widely used in industry. To identify a specific biomarker for these carcinogens in cells, the cellular proteome of L5178Y mouse lymphoma cells treated with these compounds was analyzed by 2-dimensional gel electrophoresis (2-DE) and MALDI-TOF mass spectrometry (MS). Of 50 protein spots showing a greater than 1.5-fold increase or decrease in intensity compared to control cells on a 2-D gel, we focused on the candidate biomarker moesin. Western analysis using monoclonal rabbit anti-moesin confirmed the identity of the protein and its increased level of expression upon exposure to the carcinogenic compounds. Moesin expression also increased in cells treated with six additional genotoxic carcinogens, verifying that moesin could serve as a biomarker to monitor phenotypic change upon exposure to genotoxic carcinogens in L5178Y mouse lymphoma cells.

Effects of artichoke (Cynara scolymus) leaf and bloom head extracts on chemically induced DNA lesions in Drosophila melanogaster

PubMed Central

Jacociunas, Laura Vicedo; Dihl, Rafael Rodrigues; Lehmann, Mauricio; de Barros Falcão Ferraz, Alexandre; Richter, Marc François; da Silva, Juliana; de Andrade, Heloísa Helena Rodrigues

2014-01-01

The genotoxicity of bloom head (BHE) and leaf (LE) extracts from artichoke (Cynara scolymus L.), and their ability to modulate the mutagenicity and recombinogenicity of two alkylating agents (ethyl methanesulfonate – EMS and mitomycin C – MMC) and the intercalating agent bleomycin (BLM), were examined using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. Neither the mutagenicity nor the recombinogenicity of BLM or MMC was modified by co- or post-treatment with BHE or LE. In contrast, co-treatment with BHE significantly enhanced the EMS-induced genotoxicity involving mutagenic and/or recombinant events. Co-treatment with LE did not alter the genotoxicity of EMS whereas post-treatment with the highest dose of LE significantly increased this genotoxicity. This enhancement included a synergistic increase restricted to somatic recombination. These results show that artichoke extracts promote homologous recombination in proliferative cells of D. melanogaster. PMID:24688296

Effects of artichoke (Cynara scolymus) leaf and bloom head extracts on chemically induced DNA lesions in Drosophila melanogaster.

PubMed

Jacociunas, Laura Vicedo; Dihl, Rafael Rodrigues; Lehmann, Mauricio; de Barros Falcão Ferraz, Alexandre; Richter, Marc François; da Silva, Juliana; de Andrade, Heloísa Helena Rodrigues

2014-03-01

The genotoxicity of bloom head (BHE) and leaf (LE) extracts from artichoke (Cynara scolymus L.), and their ability to modulate the mutagenicity and recombinogenicity of two alkylating agents (ethyl methanesulfonate - EMS and mitomycin C - MMC) and the intercalating agent bleomycin (BLM), were examined using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. Neither the mutagenicity nor the recombinogenicity of BLM or MMC was modified by co- or post-treatment with BHE or LE. In contrast, co-treatment with BHE significantly enhanced the EMS-induced genotoxicity involving mutagenic and/or recombinant events. Co-treatment with LE did not alter the genotoxicity of EMS whereas post-treatment with the highest dose of LE significantly increased this genotoxicity. This enhancement included a synergistic increase restricted to somatic recombination. These results show that artichoke extracts promote homologous recombination in proliferative cells of D. melanogaster.

Investigation of the Genotoxicity of Aluminum Oxide, β-Tricalcium Phosphate, and Zinc Oxide Nanoparticles In Vitro.

PubMed

Akbaba, Giray Buğra; Türkez, Hasan

The aim of this study was to investigate the genotoxicity of aluminum oxide (Al 2 O 3 ), β-tricalcium phosphate (β-TCP) (Ca 3 (PO 4 ) 2 ), and zinc oxide (ZnO) nanoparticles (NPs) that were 4.175, 9.058, and 19.8 nm sized, respectively, on human peripheral blood lymphocytes using micronucleus (MN) and chromosome aberration (CA) techniques. Aluminum oxide and β-TCP NPs did not show genotoxic effects on human peripheral blood cultures in vitro, even at the highest concentrations; therefore, these materials may be suitable for use as biocompatible materials. It was observed that, even at a very low dose (≥12.5 ppm), ZnO NPs had led to genotoxicity. In addition, at high concentrations (500 ppm and above), ZnO NPs caused mortality of lymphocytes. For these reasons, it was concluded that ZnO NPs are not appropriate for using as a biocompatible biomaterial.

Environmental genotoxicity: Probing the underlying mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shugart, L.; Theodorakis, C.

1993-12-31

Environmental pollution is a complex issue because of the diversity of anthropogenic agents, both chemical and physical, that have been detected and catalogued. The consequences to biota from exposure to genotoxic agents present an additional problem because of the potential for these agents to produce adverse change at the cellular and organismal levels. Past studies in genetic toxicology at the Oak Ridge National Laboratory have focused on structural damage to the DNA of environmental species that may occur after exposure to genotoxic agents and the use of this information to document exposure and to monitor remediation. In an effort tomore » predict effects at the population, community and ecosystem levels, current studies in genetic ecotoxicology are attempting to characterize the biological mechanisms at the gene level that regulate and limit the response of an individual organism to genotoxic factors in their environment.« less

Gene toxicity studies on titanium dioxide and zinc oxide nanomaterials used for UV-protection in cosmetic formulations.

PubMed

Landsiedel, Robert; Ma-Hock, Lan; Van Ravenzwaay, Ben; Schulz, Markus; Wiench, Karin; Champ, Samantha; Schulte, Stefan; Wohlleben, Wendel; Oesch, Franz

2010-12-01

Titanium dioxide and zinc oxide nanomaterials, used as UV protecting agents in sunscreens, were investigated for their potential genotoxicity in in vitro and in vivo test systems. Since standard OECD test methods are designed for soluble materials and genotoxicity testing for nanomaterials is still under revision, a battery of standard tests was used, covering different endpoints. Additionally, a procedure to disperse the nanomaterials in the test media and careful characterization of the dispersed test item was added to the testing methods. No genotoxicity was observed in vitro (Ames' Salmonella gene mutation test and V79 micronucleus chromosome mutation test) or in vivo (mouse bone marrow micronucleus test and Comet DNA damage assay in lung cells from rats exposed by inhalation). These results add to the still limited data base on genotoxicity test results with nanomaterials and provide congruent results of a battery of standard OECD test methods applied to nanomaterials.

Determination of genotoxic effects of boron and zinc on Zea mays using protein and random amplification of polymorphic DNA analyses.

PubMed

Erturk, Filiz Aygun; Nardemir, Gokce; Hilal, A Y; Arslan, Esra; Agar, Guleray

2015-11-01

In this research, we aimed to determine genotoxic effects of boron (B) and zinc (Zn) on Zea mays by using total soluble protein content and random amplification of polymorphic DNA (RAPD) analyses. For the RAPD analysis, 16 RAPD primers were found to produce unique polymorphic band profiles on treated maize seedlings. With increased Zn and B concentrations, increased polymorphism rate was observed, while genomic template stability and total soluble protein content decreased. The treatment with Zn was more effective than that of B groups on the levels of total proteins. The obtained results from this study revealed that the total soluble protein levels and RAPD profiles were performed as endpoints of genotoxicity and these analyses can offer useful biomarker assays for the evaluation of genotoxic effects on Zn and B polluted plants. © The Author(s) 2013.

Genotoxicity of metal nanoparticles.

PubMed

Xie, Hong; Mason, Michael M; Wise, John Pierce

2011-01-01

Nanotechnology is currently used in industry, medicine, and military applications, as well as in more than 300 commercial products. Yet, the same properties that make these particles exciting for technology also make them daunting public health concerns because their toxicity is unknown and relatively unexplored. Increased attention is being placed on the study of metal particle genotoxicity; however, a lot of unknowns remain about their effects and the mechanisms. In this article, we highlight some metal and metal oxide nanoparticles of interest and discuss the current in vivo and in vitro studies of genotoxic effects. Many metal nanoparticles were found to cause chromosomal aberrations, DNA strand breaks, oxidative DNA damage, and mutations. Inconsistencies are found in the literature, however, thus drawing conclusions is difficult due to a variety of factors. Therefore, the areas requiring further attention are highlighted and recommendations to improve our understanding of the genotoxic potential are addressed.

Prediction of genotoxic potential of cosmetic ingredients by an in silico battery system consisting of a combination of an expert rule-based system and a statistics-based system.

PubMed

Aiba née Kaneko, Maki; Hirota, Morihiko; Kouzuki, Hirokazu; Mori, Masaaki

2015-02-01

Genotoxicity is the most commonly used endpoint to predict the carcinogenicity of chemicals. The International Conference on Harmonization (ICH) M7 Guideline on Assessment and Control of DNA Reactive (Mutagenic) Impurities in Pharmaceuticals to Limit Potential Carcinogenic Risk offers guidance on (quantitative) structure-activity relationship ((Q)SAR) methodologies that predict the outcome of bacterial mutagenicity assay for actual and potential impurities. We examined the effectiveness of the (Q)SAR approach with the combination of DEREK NEXUS as an expert rule-based system and ADMEWorks as a statistics-based system for the prediction of not only mutagenic potential in the Ames test, but also genotoxic potential in mutagenicity and clastogenicity tests, using a data set of 342 chemicals extracted from the literature. The prediction of mutagenic potential or genotoxic potential by DEREK NEXUS or ADMEWorks showed high values of sensitivity and concordance, while prediction by the combination of DEREK NEXUS and ADMEWorks (battery system) showed the highest values of sensitivity and concordance among the three methods, but the lowest value of specificity. The number of false negatives was reduced with the battery system. We also separately predicted the mutagenic potential and genotoxic potential of 41 cosmetic ingredients listed in the International Nomenclature of Cosmetic Ingredients (INCI) among the 342 chemicals. Although specificity was low with the battery system, sensitivity and concordance were high. These results suggest that the battery system consisting of DEREK NEXUS and ADMEWorks is useful for prediction of genotoxic potential of chemicals, including cosmetic ingredients.

Nongenotoxic effects and a reduction of the DXR-induced genotoxic effects of Helianthus annuus Linné (sunflower) seeds revealed by micronucleus assays in mouse bone marrow.

PubMed

Boriollo, Marcelo Fabiano Gomes; Souza, Luiz Silva; Resende, Marielly Reis; Silva, Thaísla Andrielle da; Oliveira, Nelma de Mello Silva; Resck, Maria Cristina Costa; Dias, Carlos Tadeu dos Santos; Fiorini, João Evangelista

2014-04-02

This research evaluated the genotoxicity of oil and tincture of H. annuus L. seeds using the micronucleus assay in bone marrow of mice. The interaction between these preparations and the genotoxic effects of doxorubicin (DXR) was also analysed (antigenotoxicity test). Experimental groups were evaluated at 24-48 h post treatment with N-Nitroso-N-ethylurea (positive control - NEU), DXR (chemotherapeutic), NaCl (negative control), a sunflower tincture (THALS) and two sources of sunflower oils (POHALS and FOHALS). Antigenotoxic assays were carried out using the sunflower tincture and oils separately and in combination with NUE or DXR. For THALS, analysis of the MNPCEs showed no significant differences between treatment doses (250-2,000 mg.Kg-1) and NaCl. A significant reduction in MNPCE was observed when THALS (2,000 mg.Kg-1) was administered in combination with DXR (5 mg.Kg-1). For POHALS or FOHALS, analysis of the MNPCEs also showed no significant differences between treatment doses (250-2,000 mg.Kg-1) and NaCl. However, the combination DXR + POHALS (2,000 mg.Kg-1) or DXR + FOHALS (2,000 mg.Kg-1) not contributed to the MNPCEs reduction. This research suggests absence of genotoxicity of THALS, dose-, time- and sex-independent, and its combination with DXR can reduce the genotoxic effects of DXR. POHALS and FOHALS also showed absence of genotoxicity, but their association with DXR showed no antigenotoxic effects.

Nongenotoxic effects and a reduction of the DXR-induced genotoxic effects of Helianthus annuus Linné (sunflower) seeds revealed by micronucleus assays in mouse bone marrow

PubMed Central

2014-01-01

Background This research evaluated the genotoxicity of oil and tincture of H. annuus L. seeds using the micronucleus assay in bone marrow of mice. The interaction between these preparations and the genotoxic effects of doxorubicin (DXR) was also analysed (antigenotoxicity test). Methods Experimental groups were evaluated at 24-48 h post treatment with N-Nitroso-N-ethylurea (positive control – NEU), DXR (chemotherapeutic), NaCl (negative control), a sunflower tincture (THALS) and two sources of sunflower oils (POHALS and FOHALS). Antigenotoxic assays were carried out using the sunflower tincture and oils separately and in combination with NUE or DXR. Results For THALS, analysis of the MNPCEs showed no significant differences between treatment doses (250–2,000 mg.Kg-1) and NaCl. A significant reduction in MNPCE was observed when THALS (2,000 mg.Kg-1) was administered in combination with DXR (5 mg.Kg-1). For POHALS or FOHALS, analysis of the MNPCEs also showed no significant differences between treatment doses (250–2,000 mg.Kg-1) and NaCl. However, the combination DXR + POHALS (2,000 mg.Kg-1) or DXR + FOHALS (2,000 mg.Kg-1) not contributed to the MNPCEs reduction. Conclusions This research suggests absence of genotoxicity of THALS, dose-, time- and sex-independent, and its combination with DXR can reduce the genotoxic effects of DXR. POHALS and FOHALS also showed absence of genotoxicity, but their association with DXR showed no antigenotoxic effects. PMID:24694203

Conventional and whitening toothpastes: cytotoxicity, genotoxicity and effect on the enamel surface.

PubMed

Camargo, Samira Esteves Afonso; Jóias, Renata Pilli; Santana-Melo, Gabriela Fátima; Ferreira, Lara Tolentino; El Achkar, Vivian Narana Ribeiro; Rode, Sigmar de Mello

2014-12-01

To evaluate the cytotoxicity and genotoxicity of whitening and common toothpastes, and the surface roughness of tooth enamel submitted to brushing with both toothpastes. Samples of whitening toothpastes [Colgate Whitening (CW) and Oral-B Whitening (OBW)] and regular (non-whitening) toothpastes (Colgate and Oral-B) were extracted in culture medium. Gingival human fibroblasts (FMM-1) were placed in contact with different dilutions of culture media that had been previously exposed to such materials, and the cytotoxicity was evaluated using the MTT assay. The genotoxicity was assessed by the micronucleus formation assay in Chinese hamster fibroblasts (V79). The cell survival rate and micronuclei number were assessed before and after exposure to the toothpaste extracts. For the surface roughness evaluation, 20 bovine tooth specimens, divided into four groups according to toothpastes, were submitted to 10,000 brushing cycles. The results were analyzed using the Mann-Whitney U and two-way ANOVA tests (P < 0.05). MTT assay showed that Colgate was significantly less cytotoxic than CW, Oral-B and OBW at all dilutions (P < 0.01). CW was the most cytotoxic toothpaste (P < 0.01). The whitening toothpastes showed the highest numbers of micronuclei compared to the untreated control (UC) (P < 0.01). Colgate and Oral-B toothpastes were not genotoxic compared to UC (P = 0.326). The OBW toothpaste was statistically significantly abrasive to the enamel surface (P < 0.01). The whitening toothpastes and Oral-B were cytotoxic to the cells. The whitening toothpastes were more genotoxic to cells in vitro than the common toothpastes, and genotoxicity was more pronounced in the OBW toothpaste.

Oxcarbazepine-induced cytotoxicity and genotoxicity in human lymphocyte cultures with or without metabolic activation.

PubMed

Atlı Şekeroğlu, Zülal; Kefelioğlu, Haluk; Kontaş Yedier, Seval; Şekeroğlu, Vedat; Delmecioğlu, Berrin

2017-03-01

There has been considerable debate about the relationship between epilepsy and cancer. Oxcarbazepine (OXC) is used for treating certain types of seizures in patients with epilepsy. There have been no detailed investigations about genotoxicity of OXC and its metabolites. Therefore, the aim of this study is to investigate the cytotoxic and genotoxic effects of OXC and its metabolites on cultured human lymphocytes. The cytotoxicity and genotoxicity of OXC on human peripheral blood lymphocytes were examined in vitro by sister chromatid exchange (SCE), chromosomal aberration (CA) and micronucleus (MN) tests. Cultures were treated with 125, 250 and 500 μg/ml of OXC in the presence (3 h treatment) and absence (24 h and 48 h treatment) of a metabolic activator (S9 mix). Dimethyl sulfoxide (DMSO) was used as a solvent control. OXC showed cytotoxic activities due to significant decreases in mitotic index (MI), proliferation index (PI) and nuclear division index (NDI) in the absence of S9 mix when compared with solvent control. Metabolites of OXC also significantly reduced MI and PI in cultures with S9 mix. OXC significantly increased the CAs, aberrant cells, SCE and MN values in the presence and absence of S9 mix. Our results indicated that both OXC and its metabolites have cytotoxic, cytostatic and genotoxic potential on human peripheral blood lymphocyte cultures under the experimental conditions. Further studies are necessary to elucidate the relationship between cytotoxic, cytostatic and genotoxic effects, and to make a possible risk assessment in patients receiving therapy with this drug.

Cross-Platform Toxicogenomics for the Prediction of Non-Genotoxic Hepatocarcinogenesis in Rat

PubMed Central

Metzger, Ute; Templin, Markus F.; Plummer, Simon; Ellinger-Ziegelbauer, Heidrun; Zell, Andreas

2014-01-01

In the area of omics profiling in toxicology, i.e. toxicogenomics, characteristic molecular profiles have previously been incorporated into prediction models for early assessment of a carcinogenic potential and mechanism-based classification of compounds. Traditionally, the biomarker signatures used for model construction were derived from individual high-throughput techniques, such as microarrays designed for monitoring global mRNA expression. In this study, we built predictive models by integrating omics data across complementary microarray platforms and introduced new concepts for modeling of pathway alterations and molecular interactions between multiple biological layers. We trained and evaluated diverse machine learning-based models, differing in the incorporated features and learning algorithms on a cross-omics dataset encompassing mRNA, miRNA, and protein expression profiles obtained from rat liver samples treated with a heterogeneous set of substances. Most of these compounds could be unambiguously classified as genotoxic carcinogens, non-genotoxic carcinogens, or non-hepatocarcinogens based on evidence from published studies. Since mixed characteristics were reported for the compounds Cyproterone acetate, Thioacetamide, and Wy-14643, we reclassified these compounds as either genotoxic or non-genotoxic carcinogens based on their molecular profiles. Evaluating our toxicogenomics models in a repeated external cross-validation procedure, we demonstrated that the prediction accuracy of our models could be increased by joining the biomarker signatures across multiple biological layers and by adding complex features derived from cross-platform integration of the omics data. Furthermore, we found that adding these features resulted in a better separation of the compound classes and a more confident reclassification of the three undefined compounds as non-genotoxic carcinogens. PMID:24830643

Thinner inhalation effects on oxidative stress and DNA repair in a rat model of abuse.

PubMed

Martínez-Alfaro, Minerva; Cárabez-Trejo, Alfonso; Gallegos-Corona, Marco-Antonio; Pedraza-Aboytes, Gustavo; Hernández-Chan, Nancy Georgina; Leo-Amador, Guillermo Enrique

2010-04-01

Humans can come into contact with thinner by occupational exposure or by intentional inhalation abuse. Numerous studies of workers for genotoxic effects of thinner exposure have yielded conflicting results, perhaps because co-exposure to variable other compounds cannot be avoided in workplace exposure studies. In contrast, there is no data concerning the genotoxic effects of intentional inhalation abuse. The aim of this project was to examine the genotoxic effects of thinner inhalation in an animal model of thinner abuse (rats exposed to 3000 ppm toluene, a high solvent concentration over a very short, 15 min time period, twice a day for 6 weeks). The data presented here provides evidence that thinner inhalation in our experimental conditions is able to induce weight loss, lung abnormalities and oxidative stress. This oxidative stress induces oxidative DNA damage that is not a characteristic feature of genotoxic damage. No significant difference in DNA damage and DNA repair (biomarkers of genotoxicity) in lymphocytes from thinner-treated and control rats was found. Lead treatment was used as a positive control in these assays. Finally, bone marrow was evaluated as a biomarker of cellular alteration associated with thinner inhalation. The observed absence of hemopoietic and genetic toxicity could be explained in part by the absence of benzene, the only carcinogenic component of thinner; however, benzene is no longer a common component of thinner. In conclusion, thinner did not cause genotoxic effects in an experimental model of intentional abuse despite the fact that thinner inhalation induces oxidative stress. (c) 2009 John Wiley & Sons, Ltd.

Role of Zucchini and Its Distinctive Components in the Modulation of Degenerative Processes: Genotoxicity, Anti-Genotoxicity, Cytotoxicity and Apoptotic Effects

PubMed Central

Martínez-Valdivieso, Damián; Font, Rafael; Fernández-Bedmar, Zahira; Merinas-Amo, Tania; Gómez, Pedro; Alonso-Moraga, Ángeles

2017-01-01

Zucchini (Cucurbita pepo subsp. pepo) is a seasonal vegetable with high nutritional and medical values. Many useful properties of this fruit are attributed to bioactive compounds. Zucchini fruits (“Yellow” and “Light Green” varieties) and four distinctive components (lutein, β-carotene, zeaxanthin and dehydroascorbic acid) were selected. Firstly, the lutein, β-carotene, zeaxanthin and dehydroascorbic acid contents were determined in these fruits. Then, in order to evaluate the safety and suitability of their use, different assays were carried out: (i) genotoxicity and anti-genotoxicity tests to determine the safety and DNA-protection against hydrogen peroxide; (ii) cytotoxicity; and (iii) DNA fragmentation and Annexin V/PI (Propidium Iodide) assays to evaluate the pro-apoptotic effect. Results showed that: (i) all the substances were non-genotoxic; (ii) all the substances were anti-genotoxic except the highest concentration of lutein; (iii) “Yellow” zucchini epicarp and mesocarp exhibited the highest cytotoxic activity (IC50 > 0.1 mg/mL and 0.2 mg/mL, respectively); and (iv) “Light Green” zucchini skin induced internucleosomal DNA fragmentation, β-carotene being the possible molecule responsible for its pro-apoptotic activity. To sum up, zucchini fruit could play a positive role in human health and nutrition due to this fruit and its components were safe, able to inhibit significantly the H2O2-induced damage and exhibit anti-proliferative and pro-apoptotic activities toward HL60 (human promyelocytic leukemia cells) tumor cells. The information generated from this research should be considered when selecting potential accessions for breeding program purposes. PMID:28708122

Role of Zucchini and Its Distinctive Components in the Modulation of Degenerative Processes: Genotoxicity, Anti-Genotoxicity, Cytotoxicity and Apoptotic Effects.

PubMed

Martínez-Valdivieso, Damián; Font, Rafael; Fernández-Bedmar, Zahira; Merinas-Amo, Tania; Gómez, Pedro; Alonso-Moraga, Ángeles; Del Río-Celestino, Mercedes

2017-07-14

Zucchini ( Cucurbita pepo subsp. pepo ) is a seasonal vegetable with high nutritional and medical values. Many useful properties of this fruit are attributed to bioactive compounds. Zucchini fruits ("Yellow" and "Light Green" varieties) and four distinctive components (lutein, β-carotene, zeaxanthin and dehydroascorbic acid) were selected. Firstly, the lutein, β-carotene, zeaxanthin and dehydroascorbic acid contents were determined in these fruits. Then, in order to evaluate the safety and suitability of their use, different assays were carried out: (i) genotoxicity and anti-genotoxicity tests to determine the safety and DNA-protection against hydrogen peroxide; (ii) cytotoxicity; and (iii) DNA fragmentation and Annexin V/PI (Propidium Iodide) assays to evaluate the pro-apoptotic effect. Results showed that: (i) all the substances were non-genotoxic; (ii) all the substances were anti-genotoxic except the highest concentration of lutein; (iii) "Yellow" zucchini epicarp and mesocarp exhibited the highest cytotoxic activity (IC 50 > 0.1 mg/mL and 0.2 mg/mL, respectively); and (iv) "Light Green" zucchini skin induced internucleosomal DNA fragmentation, β-carotene being the possible molecule responsible for its pro-apoptotic activity. To sum up, zucchini fruit could play a positive role in human health and nutrition due to this fruit and its components were safe, able to inhibit significantly the H₂O₂-induced damage and exhibit anti-proliferative and pro-apoptotic activities toward HL60 (human promyelocytic leukemia cells) tumor cells. The information generated from this research should be considered when selecting potential accessions for breeding program purposes.

Comparative Study of Genotoxicity in Different Tobacco Related Habits using Micronucleus Assay in Exfoliated Buccal Epithelial Cells

PubMed Central

Guruprasad, Yadavalli; Jose, Maji; Saxena, Kartikay; K, Deepa; Prabhu, Vishnudas

2014-01-01

Background: Oral cancer is one of the most debilitating diseases afflicting mankind. Consumption of tobacco in various forms constitutes one of the most important etiological factors in initiation of oral cancer. When the focus of today’s research is to determine early genotoxic changes in human cells, micronucleus (MN) assay provides a simple, yet reliable indicator of genotoxic damage. Aims and Objectives: To identify and quantify micronuclei in the exfoliated cells of oral mucosa in individuals with different tobacco related habits and control group, to compare the genotoxicity of different tobacco related habits between each group and also with that of control group. Patients and Methods: In the present study buccal smears of 135 individuals with different tobacco related habits & buccal smears of 45 age and sex matched controls were obtained, stained using Giemsa stain and then observed under 100X magnification in order to identify and quantify micronuclei in the exfoliated cells of oral mucosa. Results: The mean Micronucleus (MN) count in individuals having smoking habit were 3.11 while the count was 0.50, 2.13, and 1.67 in normal control, smoking with beetle quid and smokeless tobacco habit respectively. MN count in smokers group was 2.6 times more compared to normal controls. MN count was more even in other groups when compared to normal control but to a lesser extent. Conclusion: From our study we concluded that tobacco in any form is genotoxic especially smokers are of higher risk and micronucleus assay can be used as a simple yet reliable marker for genotoxic evaluation. PMID:24995238

Genotoxicity assessment of magnetic iron oxide nanoparticles with different particle sizes and surface coatings

NASA Astrophysics Data System (ADS)

Liu, Yanping; Xia, Qiyue; Liu, Ying; Zhang, Shuyang; Cheng, Feng; Zhong, Zhihui; Wang, Li; Li, Hongxia; Xiao, Kai

2014-10-01

Magnetic iron oxide nanoparticles (IONPs) have been widely used for various biomedical applications such as magnetic resonance imaging and drug delivery. However, their potential toxic effects, including genotoxicity, need to be thoroughly understood. In the present study, the genotoxicity of IONPs with different particle sizes (10, 30 nm) and surface coatings (PEG, PEI) were assessed using three standard genotoxicity assays, the Salmonella typhimurium reverse mutation assay (Ames test), the in vitro mammalian chromosome aberration test, and the in vivo micronucleus assay. In the Ames test, SMG-10 (PEG coating, 10 nm) showed a positive mutagenic response in all the five test bacterial strains with and without metabolic activation, whereas SEI-10 (PEI coating, 10 nm) showed no mutagenesis in all tester strains regardless of metabolic activation. SMG-30 (PEG coating, 30 nm) was not mutagenic in the absence of metabolic activation, and became mutagenic in the presence of metabolic activation. In the chromosomal aberration test, no increase in the incidence of chromosomal aberrations was observed for all three IONPs. In the in vivo micronucleus test, there was no evidence of increased micronuclei frequencies for all three IONPs, indicating that they were not clastogenic in vivo. Taken together, our results demonstrated that IONPs with PEG coating exhibited mutagenic activity without chromosomal and clastogenic abnormalities, and smaller IONPs (SMG-10) had stronger mutagenic potential than larger ones (SMG-30); whereas, IONPs with SEI coating (SEI-10) were not genotoxic in all three standard genotoxicity assays. This suggests that the mutagenicity of IONPs depends on their particle size and surface coating.

METHYLATED TRIVALENT ARSENIC SPECIES ARE GENOTOXIC

EPA Science Inventory

ABSTRACT

The genotoxic effects of arsenic compounds are generally believed to result from other than direct interacton with DNA. The reactivties of methyloxarsine (MAsIII) and iododimethylarsine (DMAsIII), two methylated trivalent arsenicals, toward supercoiled X174 RFI ...

Arsenic Is A Genotoxic Carcinogen

EPA Science Inventory

Arsenic is a recognized human carcinogen; however, there is controversy over whether or not it should be considered a genotoxic carcinogen. Many possible modes of action have been proposed on how arsenic induces cancer, including inhibiting DNA repair, altering methylation patter...

METABOLISM AND GENOTOXICITY OF 1-NITROPYRENE

EPA Science Inventory

1-Nitropyrene (NP), a nitrated polycyclic aromatic hydrocarbon and a potent bacterial mutagen, has been identified in combustion emissions and may contribute to the burden of genotoxicity associated with air pollution. NP undergoes rapid metabolism by rat hepatic subcellular frac...

THE GENOTOXICITY OF AMBIENT OUTDOOR AIR, A REVIEW: SALMONELLA MUTAGENICITY

EPA Science Inventory

The genotoxicity of ambient outdoor air, a review: Salmonella mutagenicity

Abstract
Mutagens in urban air pollution come from anthropogenic sources (especially combustion sources) and are products of airborne chemical reactions. Bacterial mutation tests have been used ...

IS THE DOSE-RESPONSE LINEAR OR NONLINEAR FOR GENOTOXIC EFFECTS?

EPA Science Inventory

IS THE DOSE-RESPONSE LINEAR OR NONLINEAR FOR GENOTOXIC EFFECTS?
Preston, RJ. Environmental Carcinogenesis Division, NHEERL, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

For considerations of cancer risk assessment from exposure to environmenta...

Intermediate frequency magnetic field generated by a wireless power transmission device does not cause genotoxicity in vitro.

PubMed

Shi, Dejing; Zhu, Chunbo; Lu, Rengui; Mao, Shitong; Qi, Yanhua

2014-10-01

The aim of this study was to evaluate effects of intermediate frequency magnetic fields (IFMF) generated by a wireless power transmission (WPT) based on magnetic resonance from the perspective of cellular genotoxicity on cultured human lens epithelial cells (HLECs). We evaluated the effects of exposure to 90 kHz magnetic fields at 93.36 µT on cellular genotoxicity in vitro for 2 and 4 h. The magnetic flux density is approximately 3.5 times higher than the reference level recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. For assessment of genotoxicity, we studied cellular proliferation, apoptosis and DNA damage by Cell Counting Kit-8 (CCK-8) assay, flow cytometry analysis, alkaline comet assay and phosphorylated histone H2AX (γH2AX) foci formation test. We did not detect any effect of a 90 kHz IFMF generated by WPT based on magnetic resonance on cell proliferation, apoptosis, comet assay, and γH2AX foci formation test. Our results indicated that exposure to 90 kHz IFMF generated by WPT based on magnetic resonance at 93.36 µT for 2 and 4 h does not cause detectable cellular genotoxicity. © 2014 Wiley Periodicals, Inc.

Synergistic effect of Gentiana lutea L. on methyl methanesulfonate genotoxicity in the Drosophila wing spot test.

PubMed

Patenković, Aleksandra; Stamenković-Radak, Marina; Nikolić, Dragana; Marković, Tamara; Anđelković, Marko

2013-03-27

Gentiana lutea L., the yellow gentian, is herb known for its pharmacological properties, with a long tradition of use for the treatment of a variety of diseases including the use as a remedy for digestion, also in food products and in bitter beverages. The aim of the present study is to evaluate, for the first time, genotoxicity of gentian alone, and its antigenotoxicity against methyl methanesulfonate (MMS). The water infusion of the underground part of gentian were evaluated in vivo using the Drosophila wing spot test, at the dose commonly used in traditional medicine. For antigenotoxic study two types of treatment with gentian and MMS were performed: chronic co-treatment, as well as post-treatment with gentian after acute exposure with MMS. Water infusion of gentian alone did not exhibit genotoxicity. The results of co- and post-treatment experiments with gentian show that gentian enhanced the frequency of mutant clones over the values obtained with MMS alone, instead of reducing the genotoxicity of MMS, for 22.64% and 27.13% respectively. This result suggests a synergism of gentian with MMS, and indicates that water infusion of gentian used in traditional medicine may have particular effects with regard to genotoxicity indicating careful use. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Evaluation of the Bronchorelaxant, Genotoxic, and Antigenotoxic Effects of Cassia alata L.

PubMed Central

Ouédraogo, M.; Da, F. L.; Fabré, A.; Konaté, K.; Dibala, C. I.; Carreyre, H.; Thibaudeau, S.; Coustard, J.-M.; Vandebrouck, C.; Bescond, J.; Belemtougri, R. G.

2013-01-01

Aqueous-ethanolic extract of Cassia alata (AECal) and its derived fractions obtained through liquid-liquid fractionation were evaluated for their bronchorelaxant, genotoxic, and antigenotoxic effects. Contractile activity of rats' tracheas in the presence of tested materials, as well as its modifications with different inhibitors and blockers, was isometrically recorded. The antigenotoxic potential of AECal was evaluated on cyclophosphamide- (CP-) induced genotoxicity in the rat. Animals were pretreated with the extract, then liver comet assay was performed. AECal and its chloroformic fractions (CF-AECal) relaxed the contraction induced by Ach, but both were significantly less potent in inhibiting contraction induced by KCl (30 mM; 80 mM). Propranolol, indomethacin, L-NAME, methylene blue, and glibenclamide did not modify the relaxant effect of CF-AECal. TEA altered the response of trachea to CF-AECal. CF-AECal caused a rightward shift without affecting the E max in cumulative concentration-response curves of Ach only at low concentrations. In animals pretreated with the extract, the percentage of CP-induced DNA damage decreased. Our results suggest that (1) muscarinic receptors contribute at least in part to the relaxant effects of CF-AECal; (2) CF-AECal interferes with membrane polarization; and (3) AECal is not genotoxic in vivo and contains chemopreventive phytoconstituents offering protection against CP-induced genotoxicity. PMID:23710211

Approaches to the risk assessment of genotoxic carcinogens in food: a critical appraisal.

PubMed

O'Brien, J; Renwick, A G; Constable, A; Dybing, E; Müller, D J G; Schlatter, J; Slob, W; Tueting, W; van Benthem, J; Williams, G M; Wolfreys, A

2006-10-01

The present paper examines the particular difficulties presented by low levels of food-borne DNA-reactive genotoxic carcinogens, some of which may be difficult to eliminate completely from the diet, and proposes a structured approach for the evaluation of such compounds. While the ALARA approach is widely applicable to all substances in food that are both carcinogenic and genotoxic, it does not take carcinogenic potency into account and, therefore, does not permit prioritisation based on potential risk or concern. In the absence of carcinogenicity dose-response data, an assessment based on comparison with an appropriate threshold of toxicological concern may be possible. When carcinogenicity data from animal bioassays are available, a useful analysis is achieved by the calculation of margins of exposure (MOEs), which can be used to compare animal potency data with human exposure scenarios. Two reference points on the dose-response relationship that can be used for MOE calculation were examined; the T25 value, which is derived from linear extrapolation, and the BMDL10, which is derived from mathematical modelling of the dose-response data. The above approaches were applied to selected food-borne genotoxic carcinogens. The proposed approach is applicable to all substances in food that are DNA-reactive genotoxic carcinogens and enables the formulation of appropriate semi-quantitative advice to risk managers.

Sex-related effects of imidacloprid modulated by piperonyl butoxide and menadione in rats. Part II: genotoxic and cytotoxic potential.

PubMed

Arslan, Mehmet; Sevgiler, Yusuf; Buyukleyla, Mehmet; Yardimci, Mustafa; Yilmaz, Mehmet; Rencuzogullari, Eyyup

2016-01-01

Despite its intended use, imidacloprid causes genotoxic and cytotoxic effects in mammals, especially in the presence of metabolic activation systems. The aim of this study was to determine to which extent these effects are sex related and how its metabolism modulators piperonyl butoxide and menadione affect its toxicity. Male and female Sprague-Dawley rats were injected with the intraperitoneal LD50 dose of imidacloprid alone (170 mg/kg) or pretreated with piperonyl butoxide (100 mg/kg) and menadione (25 mg/kg) for 12 and 24 h. Structural chromosome aberrations, abnormal cells and mitotic index were determined microscopically in bone marrow cells. Male rats showed susceptibility to the genotoxic effects of imidacloprid. Piperonyl butoxide was effective in countering this effect only at 24 h, whereas menadione exacerbated imidacloprid-induced genotoxicity. Piperonyl butoxide and menadione pretreatments increased the percentage of structural chromosome aberrations and abnormal cells in females. Imidacloprid decreased the mitotic index, whereas pretreatment with piperonyl butoxide and menadione showed improvement in both sexes. We believe that CYP450-mediated metabolism of imidacloprid is under the hormonal control and therefore that its genotoxicity is sex related. Piperonyl butoxide pretreatment also showed sex-related modulation. The hormonal effects on imidacloprid biotransformation require further investigation.

Gamma radiation at a human relevant low dose rate is genotoxic in mice

NASA Astrophysics Data System (ADS)

Graupner, Anne; Eide, Dag M.; Instanes, Christine; Andersen, Jill M.; Brede, Dag A.; Dertinger, Stephen D.; Lind, Ole C.; Brandt-Kjelsen, Anicke; Bjerke, Hans; Salbu, Brit; Oughton, Deborah; Brunborg, Gunnar; Olsen, Ann K.

2016-09-01

Even today, 70 years after Hiroshima and accidents like in Chernobyl and Fukushima, we still have limited knowledge about the health effects of low dose rate (LDR) radiation. Despite their human relevance after occupational and accidental exposure, only few animal studies on the genotoxic effects of chronic LDR radiation have been performed. Selenium (Se) is involved in oxidative stress defence, protecting DNA and other biomolecules from reactive oxygen species (ROS). It is hypothesised that Se deficiency, as it occurs in several parts of the world, may aggravate harmful effects of ROS-inducing stressors such as ionising radiation. We performed a study in the newly established LDR-facility Figaro on the combined effects of Se deprivation and LDR γ exposure in DNA repair knockout mice (Ogg1-/-) and control animals (Ogg1+/-). Genotoxic effects were seen after continuous radiation (1.4 mGy/h) for 45 days. Chromosomal damage (micronucleus), phenotypic mutations (Pig-a gene mutation of RBCCD24-) and DNA lesions (single strand breaks/alkali labile sites) were significantly increased in blood cells of irradiated animals, covering three types of genotoxic activity. This study demonstrates that chronic LDR γ radiation is genotoxic in an exposure scenario realistic for humans, supporting the hypothesis that even LDR γ radiation may induce cancer.

Exposure to lambda-cyhalothrin, a synthetic pyrethroid, increases reactive oxygen species production and induces genotoxicity in rat peripheral blood.

PubMed

Fetoui, Hamadi; Feki, Ameni; Salah, Ghada Ben; Kamoun, Hassen; Fakhfakh, Feiza; Gdoura, Radhouane

2015-05-01

Lambda-cyhalothrin (LTC) is a synthetic pyrethroid with a broad spectrum of insecticidal and acaricidal activities used to control a wide range of insect pests in a variety of applications. However, there is little known about its adverse effects, in particular those related to its genotoxicity in humans. To elucidate the genotoxicity mechanisms of LTC, the micronuclei (MN) frequencies, the levels of reactive oxygen species (ROS), erythrocyte osmotic fragility, nitrite (NO) formation, protein carbonyl (PCO) levels and malondialdehyde (MDA) production were evaluated for a period of 7, 14 and 21 days. Our results show that exposure rat to LTC (1/10DL50 = 6.23 mg/kg) for a period of 7, 14 and 21 days induced a noticeable genotoxic effect in rat peripheral blood evidenced by a significant increase in the frequency of MN only at day 21 of treatment. Significant differences between the two groups were observed in erythrocyte osmotic fragility. Further, a significant (p < 0.01) increase in ROS contents, NO formation, PCO levels and lipid peroxidation in erythrocytes were observed at different times of treatments, suggesting the implication of oxidative stress in its toxicity. These results confirm the genotoxic and the pro-oxidant effects of LTC in rat peripheral blood. © The Author(s) 2013.

Review of genotoxicity biomonitoring studies of glyphosate-based formulations

PubMed Central

Kier, Larry D.

2015-01-01

Abstract Human and environmental genotoxicity biomonitoring studies involving exposure to glyphosate-based formulations (GBFs) were reviewed to complement an earlier review of experimental genotoxicity studies of glyphosate and GBFs. The environmental and most of the human biomonitoring studies were not informative because there was either a very low frequency of GBF exposure or exposure to a large number of pesticides without analysis of specific pesticide effects. One pesticide sprayer biomonitoring study indicated there was not a statistically significant relationship between frequency of GBF exposure reported for the last spraying season and oxidative DNA damage. There were three studies of human populations in regions of GBF aerial spraying. One study found increases for the cytokinesis-block micronucleus endpoint but these increases did not show statistically significant associations with self-reported spray exposure and were not consistent with application rates. A second study found increases for the blood cell comet endpoint at high exposures causing toxicity. However, a follow-up to this study 2 years after spraying did not indicate chromosomal effects. The results of the biomonitoring studies do not contradict an earlier conclusion derived from experimental genotoxicity studies that typical GBFs do not appear to present significant genotoxic risk under normal conditions of human or environmental exposures. PMID:25687244

Evaluation of genotoxic effects caused by extracts of chlorinated drinking water using a combination of three different bioassays.

PubMed

Zeng, Qiang; Zhang, Shao-Hui; Liao, Jing; Miao, Dong-Yue; Wang, Xin-Yi; Yang, Pan; Yun, Luo-Jia; Liu, Ai-Lin; Lu, Wen-Qing

2015-10-15

Potential genotoxic effects of chlorinated drinking water now are of a great concern. In this study, raw water, finished water, and tap water from a water plant in Wuhan, China were collected in two different sampling times of the year (January and July). Genotoxic effects of water extracts were evaluated using a combination of three different bioassays: SOS/umu test, HGPRT gene mutation assay, and micronucleus assay, which were separately used to detect DNA damage, gene mutation, and chromosome aberration. The results of three different bioassays showed that all water samples in January and July induced at least one types of genotoxic effects, of which the DNA-damage effects were all detectable. The levels of DNA-damage effects and gene-mutation effects of finished water and tap water in January were higher than those in July. Chlorination could increase the DNA-damage effects of drinking water in January and the gene-mutation effects of drinking water in both January and July, but did not increase the chromosome-aberration effects of drinking water in both January and July. Our results highlighted the importance of using a combination of different bioassays to evaluate the genotoxicity of water samples in different seasons. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of industrial effluents originated from different industrial activities.

PubMed

Pathiratne, Asoka; Hemachandra, Chamini K; De Silva, Nimal

2015-12-01

Efficacy of Allium cepa test system for screening cytotoxicity and genotoxicity of treated effluents originated from four types of industrial activities (two textile industries, three rubber based industries, two common treatment plants of industrial zones, and two water treatment plants) was assessed. Physico-chemical parameters including the heavy metal/metalloid levels of the effluents varied depending on the industry profile, but most of the measured parameters in the effluents were within the specified tolerance limits of Sri Lankan environmental regulations for discharge of industrial effluents into inland surface waters. In the A. cepa test system, the undiluted effluents induced statistically significant root growth retardation, mitosis depression, and chromosomal aberrations in root meristematic cells in most cases in comparison to the dilution water and upstream water signifying effluent induced cytotoxicity and genotoxicity. Ethyl methane sulphonate (a mutagen, positive control) and all the effluents under 1:8 dilution significantly induced total chromosomal aberrations in root meristematic cells in comparison to the dilution water and upstream water indicating inadequacy of expected 1:8 dilutions in the receiving waters for curtailing genotoxic impacts. The results support the use of a practically feasible A. cepa test system for rapid screening of cytotoxicity and genotoxicity of diverse industrial effluents discharging into inland surface waters.

Chromosome-damaging activity of saliva of betel nut and tobacco chewers.

PubMed

Stich, H F; Stich, W

1982-01-01

Saliva of volunteers chewing betel quid, cured betel nut (Areca catechu), betel leaves (Piper betle), a mixture of quid ingredients (dried betel nut flakes, catechu, cardamon, lime, copra and menthol) and Indian tobacco was collected and examined for its genotoxic activity. Chromosome aberrations (chromatid breaks and chromatid exchanges) in Chinese hamster ovary (CHO) cells were used to estimate the genotoxic effect. No detectable levels of clastogenic activity were observed in the saliva of non-chewing individuals. After 5 min of chewing betel quid, betel nut, betel leaves, quid ingredients and Indian tobacco, the saliva samples showed relatively potent clastogenic activities. The addition of transition metals Mn2+ and Cu2+ to the saliva samples of betel nut and Indian tobacco chewers enhanced their clastogenic activities, whereas Fe3+ increased the clastogenicity of the betel nut saliva but decreased the genotoxic effect of the saliva of Indian tobacco chewers. After removal of the betel quid or its components from the mouth, the clastogenic activity disappeared within 5 min. The western-type chewing tobacco did not produce a genotoxic activity in the saliva of chewers. A possible association between the genotoxicity in the saliva of betel quid chewers and the development of oral, pharyngeal and esophageal carcinomas is discussed.

Evaluation of genetic damage induced by glyphosate isopropylamine salt using Tradescantia bioassays.

PubMed

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Arámbula, Alma Rosa Villalobos; Sandoval, Alfonso Islas; Vasquez, Hugo Castañeda; González Montes, Rosa María

2011-01-01

Glyphosate is noted for being non-toxic in fishes, birds and mammals (including humans). Nevertheless, the degree of genotoxicity is seriously controversial. In this work, various concentrations of a glyphosate isopropylamine salt were tested using two methods of genotoxicity assaying, viz., the pink mutation assay with Tradescantia (4430) and the comet assay with nuclei from staminal cells of the same plant. Staminal nuclei were studied in two different forms, namely nuclei from exposed plants, and nuclei exposed directly. Using the pink mutation assay, isopropylamine induced a total or partial loss of color in staminal cells, a fundamental criterion utilized in this test. Consequently, its use is not recommended when studying genotoxicity with agents that produce pallid staminal cells. The comet assay system detected statistically significant (p < 0.01) genotoxic activity by isopropylamine, when compared to the negative control in both the nuclei of treated plants and directly treated nuclei, but only the treated nuclei showed a dose-dependent increase. Average migration in the nuclei of treated plants increased, when compared to that in treated nuclei. This was probably due, either to the permanence of isopropylamine in inflorescences, or to the presence of secondary metabolites. In conclusion, isopropylamine possesses strong genotoxic activity, but its detection can vary depending on the test systems used.

Evaluation of genetic damage induced by glyphosate isopropylamine salt using Tradescantia bioassays

PubMed Central

Alvarez-Moya, Carlos; Silva, Mónica Reynoso; Arámbula, Alma Rosa Villalobos; Sandoval, Alfonso Islas; Vasquez, Hugo Castañeda; González Montes, Rosa María

2011-01-01

Glyphosate is noted for being non-toxic in fishes, birds and mammals (including humans). Nevertheless, the degree of genotoxicity is seriously controversial. In this work, various concentrations of a glyphosate isopropylamine salt were tested using two methods of genotoxicity assaying, viz., the pink mutation assay with Tradescantia (4430) and the comet assay with nuclei from staminal cells of the same plant. Staminal nuclei were studied in two different forms, namely nuclei from exposed plants, and nuclei exposed directly. Using the pink mutation assay, isopropylamine induced a total or partial loss of color in staminal cells, a fundamental criterion utilized in this test. Consequently, its use is not recommended when studying genotoxicity with agents that produce pallid staminal cells. The comet assay system detected statistically significant (p < 0.01) genotoxic activity by isopropylamine, when compared to the negative control in both the nuclei of treated plants and directly treated nuclei, but only the treated nuclei showed a dose-dependent increase. Average migration in the nuclei of treated plants increased, when compared to that in treated nuclei. This was probably due, either to the permanence of isopropylamine in inflorescences, or to the presence of secondary metabolites. In conclusion, isopropylamine possesses strong genotoxic activity, but its detection can vary depending on the test systems used. PMID:21637555

High-Throughput In Vivo Genotoxicity Testing: An Automated Readout System for the Somatic Mutation and Recombination Test (SMART)

PubMed Central

Kwak, Jihoon; Genovesio, Auguste; Kang, Myungjoo; Hansen, Michael Adsett Edberg; Han, Sung-Jun

2015-01-01

Genotoxicity testing is an important component of toxicity assessment. As illustrated by the European registration, evaluation, authorization, and restriction of chemicals (REACH) directive, it concerns all the chemicals used in industry. The commonly used in vivo mammalian tests appear to be ill adapted to tackle the large compound sets involved, due to throughput, cost, and ethical issues. The somatic mutation and recombination test (SMART) represents a more scalable alternative, since it uses Drosophila, which develops faster and requires less infrastructure. Despite these advantages, the manual scoring of the hairs on Drosophila wings required for the SMART limits its usage. To overcome this limitation, we have developed an automated SMART readout. It consists of automated imaging, followed by an image analysis pipeline that measures individual wing genotoxicity scores. Finally, we have developed a wing score-based dose-dependency approach that can provide genotoxicity profiles. We have validated our method using 6 compounds, obtaining profiles almost identical to those obtained from manual measures, even for low-genotoxicity compounds such as urethane. The automated SMART, with its faster and more reliable readout, fulfills the need for a high-throughput in vivo test. The flexible imaging strategy we describe and the analysis tools we provide should facilitate the optimization and dissemination of our methods. PMID:25830368

Utilization of Photochemically Induced Fluorescence Detection for HPLC Determination of Genotoxic Impurities in the Vortioxetine Manufacturing Process.

PubMed

Douša, Michal; Doubský, Jan; Srbek, Jan

2016-07-01

An analytical reversed-phase high-performance liquid chromatography (HPLC) method for the detection and quantitative determination of two genotoxic impurities at ppm level present in the vortioxetine manufacturing process is described. Applying the concept of threshold of toxicological concern, a limit of 75 ppm each for both genotoxic impurities was calculated based on the maximum daily dose of active pharmaceutical ingredients. The novel reversed-phase HPLC method with photochemically induced fluorescence detection was developed on XSELECT Charged Surface Hybrid Phenyl-Hexyl column using the mobile phase consisted a mixture of 10 mM ammonium formate pH 3.0 and acetonitrile. The elution was performed using an isocratic composition of 48:52 (v/v) at a flow rate of 1.0 mL/min. The photochemically induced fluorescence detection is based on the use of UV irradiation at 254 nm through measuring the fluorescence intensity at 300 nm and an excitation wavelength of 272 nm to produce fluorescent derivatives of both genotoxic impurities. The online photochemical conversion and detection is easily accomplished for two expected genotoxic impurities and provides a sufficiently low limit detection and quantification for the target analysis. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cytotoxicity and genotoxicity of natural resin-based experimental endodontic sealers.

PubMed

Silva, Gleyce O; Cavalcanti, Bruno N; Oliveira, Tatiana R; Bin, Claudia V; Camargo, Samira E A; Camargo, Carlos H R

2016-05-01

The development of endodontic sealers based on natural resins seems to be promising, given their improved biological properties. This study evaluated the cytotoxic and genotoxic effects of two experimental root canal sealers, based on extracts from Copaifera multijuga and Ricinus communis (castor oil polymer), comparing them to synthetic resin-based sealers: a single methacrylate-based, a multi-methacrylate-based, and an epoxy resin-based sealers. Sealers were prepared, set, and exposed to cell culture medium for 24 h at 37 °C with CO2. V79 cells were exposed to serial dilutions of the extracts of each sealer for 24 h. Cell viability was measured by the MTT assay and genotoxicity was assessed by the formation of micronuclei. The single methacrylate-based sealer had the most cytotoxic effects, with significant reduction in cell viability in all dilutions of the extract. The castor oil polymer-based sealer was, on the other hand, the most biocompatible sealer, with no cytotoxic effects at any concentration. All tested sealers were not genotoxic, excepting the single methacrylate-based sealer. The tested natural resin-based sealers presented low cytotoxic and no genotoxic effects on cell cultures. These results may suggest a good alternative to develop new endodontic sealers, in order to achieve better biological response and healing, when compared to commercially available sealers.

Genotoxicity studies of organically grown broccoli (Brassica oleracea var. italica) and its interactions with urethane, methyl methanesulfonate and 4-nitroquinoline-1-oxide genotoxicity in the wing spot test of Drosophila melanogaster.

PubMed

Heres-Pulido, María Eugenia; Dueñas-García, Irma; Castañeda-Partida, Laura; Santos-Cruz, Luis Felipe; Vega-Contreras, Viridiana; Rebollar-Vega, Rosa; Gómez-Luna, Juan Carlos; Durán-Díaz, Angel

2010-01-01

Broccoli (Brassica oleracea var. italica) has been defined as a cancer preventive food. Nevertheless, broccoli contains potentially genotoxic compounds as well. We performed the wing spot test of Drosophila melanogaster in treatments with organically grown broccoli (OGB) and co-treatments with the promutagen urethane (URE), the direct alkylating agent methyl methanesulfonate (MMS) and the carcinogen 4-nitroquinoline-1-oxide (4-NQO) in the standard (ST) and high bioactivation (HB) crosses with inducible and high levels of cytochrome P450s (CYPs), respectively. Larvae of both crosses were chronically fed with OGB or fresh market broccoli (FMB) as a non-organically grown control, added with solvents or mutagens solutions. In both crosses, the OGB added with Tween-ethanol yielded the expected reduction in the genotoxicity spontaneous rate. OGB co-treatments did not affect the URE effect, MMS showed synergy and 4-NQO damage was modulated in both crosses. In contrast, FMB controls produced damage increase; co-treatments modulated URE genotoxicity, diminished MMS damage, and did not change the 4-NQO damage. The high dietary consumption of both types of broccoli and its protective effects in D. melanogaster are discussed. Copyright 2009 Elsevier Ltd. All rights reserved.

Exposure to sorbitol during lactation causes metabolic alterations and genotoxic effects in rat offspring.

PubMed

Cardoso, Felipe S; Araujo-Lima, Carlos F; Aiub, Claudia A F; Felzenszwalb, Israel

2016-10-17

Sorbitol is a polyol used by the food industry as a sweetener. Women are consuming diet and light products containing sorbitol during pregnancy and in the postnatal period to prevent themselves from excessive weight gain and maintain a slim body. Although there is no evidence for the genotoxicity of sorbitol in the perinatal period, this study focused on evaluating the effects of the maternal intake of sorbitol on the biochemical and toxicological parameters of lactating Wistar rat offspring after 14days of mother-to-offspring exposure. A dose-dependent reduction of offspring length was observed. An increase in sorbitol levels determined in the milk was also observed. However, we detected an inverse relationship between the exposition dose in milk fructose and triacylglycerols concentrations. There was an increase in the plasmatic levels of ALT, AST and LDLc and a decrease in proteins, cholesterol and glucose levels in the offspring. Sorbitol exposure caused hepatocyte genotoxicity, including micronuclei induction. Maternal sorbitol intake induced myelotoxicity and myelosuppression in their offspring. The Comet assay of the blood cells detected a dose-dependent genotoxic response within the sorbitol-exposed offspring. According to our results, sorbitol is able to induce important metabolic alterations and genotoxic responses in the exposed offspring. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

SB202190 affects cell response to hydroxyurea-induced genotoxic stress in root meristems of Vicia faba.

PubMed

Winnicki, Konrad; Maszewski, Janusz

2012-11-01

Genotoxic stress caused by a variety of chemical and physical agents may lead to DNA breaks and genome instability. Response to DNA damage depends on ATM/ATR sensor kinases and their downstream proteins, which arrange cell cycle checkpoints. Activation of ATM (ataxia-telangiectasia-mutated)/ATR (ATM and Rad 3-related) signaling pathway triggers cell cycle arrest (by keeping cyclin-Cdk complexes inactive), combined with gamma-phosphorylation of histone H2A.X and induction of DNA repair processes. However, genotoxic stress activates also mitogen-activated protein kinases (MAPKs) which may control the functions of checkpoint proteins both directly, by post-translational modifications, or indirectly, by regulation of their expression. Our results indicate that in root meristem cells of Vicia faba, MAP kinase signaling pathway takes part in response to hydroxyurea-induced genotoxic stress. It is shown that SB202190, an inhibitor of p38 MAP kinase, triggers PCC (premature chromosome condensation) more rapidly, but only if cell cycle checkpoints are alleviated by caffeine. Since SB202190 and, independently, caffeine reduces HU-mediated histone H4 Lys5 acetylation, it may be that there is a cooperation of MAP kinase signaling pathways and ATM/ATR-dependent checkpoints during response to genotoxic stress. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Nonclinical Safety Assessment of Morus alba L. Fruits: Study of 90-D Toxicity in Sprague Dawley Rats and Genotoxicity in Salmonella.

PubMed

Chang, Bo Yoon; Kim, Seon Beom; Lee, Mi Kyeong; Park, Hyun; Kim, Sung Yeon

2016-05-01

Morus alba L. is a traditional herb with a long history of consumption, both as an edible fruit and as medicine. However, its safety evaluation has not yet been established. The objective of this study was to evaluate subchronic oral toxicity and genotoxicity of M. alba L. fruits (MFE). The subchronic toxicity after daily oral administration of MFE at 0, 40, 200, and 1000 mg/kg for 90 d was examined in Sprague Dawley (SD) rats. MFE administration did not lead to death, adverse effects, change in food and water consumption, and body weight gain. Significant toxic effects were not found within the parameters of organ weight, biochemical values, and hematological and urine analysis between the control and the MFE group. The genotoxicity of MFE was assayed by Ames test in Salmonella typhimurium strains TA98, TA102, and TA1535. No genotoxicity was found in all the tested strains. Thus in this study, a no-observed-adverse-effect level for MFE in 90 d repeated oral toxicity study in rats was determined to be greater than 1000 mg/kg regardless of gender. The results also suggested that MFE does not have a genotoxicity potential. © 2016 Institute of Food Technologists®

Chemical composition and genotoxicity assessment of sanitary landfill leachate from Rovinj, Croatia.

PubMed

Gajski, Goran; Oreščanin, Višnja; Garaj-Vrhovac, Vera

2012-04-01

Chemical analysis and an in vitro approach were performed to assess elemental composition and genotoxic effects of the samples of landfill leachate taken from Lokva Vidotto sanitary landfill the official landfill for Rovinj town, Croatia. Two samples of landfill leachate were collected and analyzed in order to evaluate macro, micro and trace elements by atomic absorption spectroscopy, energy dispersive X-ray spectrometry and colorimetry. Genotoxicity of sanitary landfill leachate was evaluated in human lymphocytes by the use of the micronucleus test and comet assay. Samples were characterized with relatively low concentrations of heavy metals while organic component level exceeded upper permissible limit up to 39 times. Observed genotoxic effects should be connected with high concentrations of ammonia nitrogen, which exceeded permissible limit up to 180 times. Leachate samples of both sanitary landfills increased the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. Increase of DNA damage in human lymphocytes was also detected by virtue of measuring comet assay parameters. All parameters showed statistically significant difference compared to negative control. Increased micronucleus and comet assay parameters indicate that both samples of sanitary landfill leachate are genotoxic and could pose environmental and human health risk if discharged to an aquatic environment. Copyright © 2011 Elsevier Inc. All rights reserved.

DNA damage and oxidative stress in human liver cell L-02 caused by surface water extracts during drinking water treatment in a waterworks in China.

PubMed

Xie, Shao-Hua; Liu, Ai-Lin; Chen, Yan-Yan; Zhang, Li; Zhang, Hui-Juan; Jin, Bang-Xiong; Lu, Wen-Hong; Li, Xiao-Yan; Lu, Wen-Qing

2010-04-01

Because of the daily and life-long exposure to disinfection by-products formed during drinking water treatment, potential adverse human health risk of drinking water disinfection is of great concern. Toxicological studies have shown that drinking water treatment increases the genotoxicity of surface water. Drinking water treatment is comprised of different potabilization steps, which greatly influence the levels of genotoxic products in the surface water and thus may alter the toxicity and genotoxicity of surface water. The aim of the present study was to understand the influence of specific steps on toxicity and genotoxicity during the treatment of surface water in a water treatment plant using liquid chlorine as the disinfectant in China. An integrated approach of the comet and oxidative stress assays was used in the study, and the results showed that both the prechlorination and postchlorination steps increased DNA damage and oxidative stress caused by water extracts in human derived L-02 cells while the tube settling and filtration steps had the opposite effect. This research also highlighted the usefulness of an integrated approach of the comet and oxidative stress assays in evaluating the genotoxicity of surface water during drinking water treatment. Copyright 2009 Wiley-Liss, Inc.

Relationship between genotoxicity and oxidative stress induced by mercury on common carp (Cyprinus carpio) tissues.

PubMed

García-Medina, Sandra; Galar-Martínez, Marcela; Gómez-Oliván, Leobardo Manuel; Ruiz-Lara, Karina; Islas-Flores, Hariz; Gasca-Pérez, Eloy

2017-11-01

Mercury is one of the most toxic metals in aquatic systems since it is able to induce neurobehavioral disorders as well as renal and gastrointestinal tract damage. The common carp Cyprinus carpio is an important species from both an ecological and economic viewpoint as it is consumed in many countries, the top producers being Mexico, China, India and Japan. The present study aimed to evaluate the relation between Hg-induced oxidative stress and genotoxicity in diverse tissues of C. carpio. Specimens were exposed to 0.01mgHg/L (the maximum permissible limit for aquatic life protection), and lipid peroxidation, protein carbonyl content and the activity of antioxidant enzymes were evaluated at 96h. Micronuclei frequency and DNA damage by comet assay were determined at 12, 24, 48, 72 and 96h. Hg induced oxidative stress and genotoxicity on exposed fish, since inhibition of antioxidant enzymes activity and increases in lipid peroxidation, DNA damage and micronuclei frequency occurred. Blood, gill and liver were more susceptible to oxidative stress, while blood were more sensitive to genotoxicity. In conclusion, Hg at concentrations equal to the maximum permissible limit for aquatic life protection induced oxidative stress and genotoxicity on C. carpio, and these two effects prove to be correlated. Copyright © 2017 Elsevier B.V. All rights reserved.

Aldehyde dehydrogenase 2 in aplastic anemia, Fanconi anemia and hematopoietic stem cells.

PubMed

Van Wassenhove, Lauren D; Mochly-Rosen, Daria; Weinberg, Kenneth I

2016-09-01

Maintenance of the hematopoietic stem cell (HSC) compartment depends on the ability to metabolize exogenously and endogenously generated toxins, and to repair cellular damage caused by such toxins. Reactive aldehydes have been demonstrated to cause specific genotoxic injury, namely DNA interstrand cross-links. Aldehyde dehydrogenase 2 (ALDH2) is a member of a 19 isoenzyme ALDH family with different substrate specificities, subcellular localization, and patterns of expression. ALDH2 is localized in mitochondria and is essential for the metabolism of acetaldehyde, thereby placing it directly downstream of ethanol metabolism. Deficiency in ALDH2 expression and function are caused by a single nucleotide substitution and resulting amino acid change, called ALDH2*2. This genetic polymorphism affects 35-45% of East Asians (about ~560 million people), and causes the well-known Asian flushing syndrome, which results in disulfiram-like reactions after ethanol consumption. Recently, the ALDH2*2 genotype has been found to be associated with marrow failure, with both an increased risk of sporadic aplastic anemia and more rapid progression of Fanconi anemia. This review discusses the unexpected interrelationship between aldehydes, ALDH2 and hematopoietic stem cell biology, and in particular its relationship to Fanconi anemia. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Genotoxic effect and antigen binding characteristics of SLE auto-antibodies to peroxynitrite-modified human DNA.

PubMed

Khan, Md Asad; Alam, Khursheed; Mehdi, Syed Hassan; Rizvi, M Moshahid A

2017-12-01

Systemic lupus erythematosus (SLE) is an inflammatory autoimmune disease characterized by auto-antibodies against native deoxyribonucleic acid after modification and is one of the reasons for the development of SLE. Here, we have evaluated the structural perturbations in human placental DNA by peroxynitrite using spectroscopy, thermal denaturation and high-performance liquid chromatography (HPLC). Peroxynitrite is a powerful potent bi-functional oxidative/nitrative agent that is produced both endogenously and exogenously. In experimental animals, the peroxynitrite-modified DNA was found to be highly immunogenic. The induced antibodies showed cross-reactions with different types of DNA and nitrogen bases that were modified with peroxynitrite by inhibition ELISA. The antibody activity was inhibited by approximately 89% with its immunogen as the inhibitor. The antigen-antibodies interaction between induced antibodies with peroxynitrite-modified DNA showed retarded mobility as compared to the native form. Furthermore, significantly increased binding was also observed in SLE autoantibodies with peroxynitrite-modified DNA than native form. Moreover, DNA isolated from lymphocyte of SLE patients revealed significant recognition of anti-peroxynitrite-modified DNA immunoglobulin G (IgG). Our data indicates that DNA modified with peroxynitrite presents unique antigenic determinants that may induce autoantibody response in SLE. Copyright © 2017 Elsevier Inc. All rights reserved.

Adult stem cell theory of the multi-stage, multi-mechanism theory of carcinogenesis: role of inflammation on the promotion of initiated stem cells.

PubMed

Trosko, James E; Tai, Mei-Hui

2006-01-01

Inflammation, induced by microbial agents, radiation, endogenous or exogenous chemicals, has been associated with chronic diseases, including cancer. Since carcinogenesis has been characterized as consisting of the 'initiation', 'promotion' and 'progression' phases, the inflammatory process could affect any or all three phases. The stem cell theory of carcinogenesis has been given a revival, in that isolated human adult stem cells have been isolated and shown to be 'targets' for neoplastic transformation. Oct4, a transcription factor, has been associated with adult stem cells, as well as their immortalized and tumorigenic derivatives, but not with the normal differentiated daughters. These data are consistent with the stem cell theory of carcinogenesis. In addition, Gap Junctional Intercellular Communication (GJIC) seems to play a major role in cell growth. Inhibition of GJIC by non-genotoxic chemicals or various oncogenes seems to be the mechanism for the tumor promotion and progression phases of carcinogenesis. Many of the toxins, synthetic non-genotoxicants, and endogenous inflammatory factors have been shown to inhibit GJIC and act as tumor promoters. The inhibition of GJIC might be the mechanism by which the inflammatory process affects cancer and that to intervene during tumor promotion with anti-inflammatory factors might be the most efficacious anti-cancer strategy.

Myeloid leukemia factor 1 regulates p53 by suppressing COP1 via COP9 signalosome subunit 3.

PubMed

Yoneda-Kato, Noriko; Tomoda, Kiichiro; Umehara, Mari; Arata, Yukinobu; Kato, Jun-ya

2005-05-04

Myeloid leukemia factor 1 (MLF1) was first identified as the leukemic fusion protein NPM-MLF1 generated by the t(3;5)(q25.1;q34) chromosomal translocation. Although MLF1 expresses normally in a variety of tissues including hematopoietic stem cells and the overexpression of MLF1 correlates with malignant transformation in human cancer, little is known about how MLF1 is involved in the regulation of cell growth. Here we show that MLF1 is a negative regulator of cell cycle progression functioning upstream of the tumor suppressor p53. MLF1 induces p53-dependent cell cycle arrest in murine embryonic fibroblasts. This action requires a novel binding partner, subunit 3 of the COP9 signalosome (CSN3). A reduction in the level of CSN3 protein with small interfering RNA abrogated MLF1-induced G1 arrest and impaired the activation of p53 by genotoxic stress. Furthermore, ectopic MLF1 expression and CSN3 knockdown inversely affect the endogenous level of COP1, a ubiquitin ligase for p53. Exogenous expression of COP1 overcomes MLF1-induced growth arrest. These results indicate that MLF1 is a critical regulator of p53 and suggest its involvement in leukemogenesis through a novel CSN3-COP1 pathway.

Local Melatoninergic System as the Protector of Skin Integrity

PubMed Central

Slominski, Andrzej T.; Kleszczyński, Konrad; Semak, Igor; Janjetovic, Zorica; Żmijewski, Michał A.; Kim, Tae-Kang; Slominski, Radomir M.; Reiter, Russel J.; Fischer, Tobias W.

2014-01-01

The human skin is not only a target for the protective actions of melatonin, but also a site of melatonin synthesis and metabolism, suggesting an important role for a local melatoninergic system in protection against ultraviolet radiation (UVR) induced damages. While melatonin exerts many effects on cell physiology and tissue homeostasis via membrane bound melatonin receptors, the strong protective effects of melatonin against the UVR-induced skin damage including DNA repair/protection seen at its high (pharmocological) concentrations indicate that these are mainly mediated through receptor-independent mechanisms or perhaps through activation of putative melatonin nuclear receptors. The destructive effects of the UVR are significantly counteracted or modulated by melatonin in the context of a complex intracutaneous melatoninergic anti-oxidative system with UVR-enhanced or UVR-independent melatonin metabolites. Therefore, endogenous intracutaneous melatonin production, together with topically-applied exogenous melatonin or metabolites would be expected to represent one of the most potent anti-oxidative defense systems against the UV-induced damage to the skin. In summary, we propose that melatonin can be exploited therapeutically as a protective agent or as a survival factor with anti-genotoxic properties or as a “guardian” of the genome and cellular integrity with clinical applications in UVR-induced pathology that includes carcinogenesis and skin aging. PMID:25272227

THE GENOTOXICITY OF PRIORITY POLYCYCLIC AROMATIC HYDROCARBONS IN COMPLEX MIXTURES

EPA Science Inventory

Risk assessment of complex environmental samples suffers from difficulty in identifying toxic components, inadequacy of available toxicity data, and a paucity of knowledge about the behavior of geno(toxic) substances in complex mixtures. Lack of information about the behavior of ...

Titanium dioxide nanoparticles cause genotoxicity in human lung epithelial cells

EPA Science Inventory

The use of engineered nanoparticles in consumer products is steadily increasing. However, the health effects of exposure to these nanoparticles are not thoroughly understood. This study investigated the genotoxicity of six titanium dioxide and two cerium oxide nanoparticles of va...

Genotoxicity studies on DNA-interactive telomerase inhibitors with application as anti-cancer agents.

PubMed

Harrington, Dean J; Cemeli, Eduardo; Carder, Joanna; Fearnley, Jamie; Estdale, Sian; Perry, Philip J; Jenkins, Terence C; Anderson, Diana

2003-01-01

Telomerase-targeted strategies have aroused recent interest in anti-cancer chemotherapy, because DNA-binding drugs can interact with high-order tetraplex rather than double-stranded (duplex) DNA targets in tumour cells. However, the protracted cell-drug exposure times necessary for clinical application require that telomerase inhibitory efficacy must be accompanied by both low inherent cytotoxicity and the absence of mutagenicity/genotoxicity. For the first time, the genotoxicity of a number of structurally diverse DNA-interactive telomerase inhibitors is examined in the Ames test using six Salmonella typhimurium bacterial strains (TA1535, TA1537, TA1538, TA98, TA100, and TA102). DNA damage induced by each agent was also assessed using the Comet assay with human lymphocytes. The two assay procedures revealed markedly different genotoxicity profiles that are likely to reflect differences in metabolism and/or DNA repair between bacterial and mammalian cells. The mutational spectrum for a biologically active fluorenone derivative, shown to be mutagenic in the TA100 strain, was characterised using a novel and rapid assay method based upon PCR amplification of a fragment of the hisG46 allele, followed by RFLP analysis. Preliminary analysis indicates that the majority (84%) of mutations induced by this compound are C --> A transversions at position 2 of the missense proline codon of the hisG46 allele. However, despite its genotoxic bacterial profile, this fluorenone agent gave a negative response in the Comet assay, and demonstrates how unwanted systemic effects (e.g., cytotoxicity and genotoxicity) can be prevented or ameliorated through suitable molecular fine-tuning of a candidate drug in targeted human tumour cells. Copyright 2003 Wiley-Liss, Inc.

Protective effect of boric acid on lead- and cadmium-induced genotoxicity in V79 cells.

PubMed

Ustündağ, Aylin; Behm, Claudia; Föllmann, Wolfram; Duydu, Yalçin; Degen, Gisela H

2014-06-01

The toxic heavy metals cadmium (Cd) and lead (Pb) are important environmental pollutants which can cause serious damage to human health. As the metal ions (Cd(2+) and Pb(2+)) accumulate in the organism, there is special concern regarding chronic toxicity and damage to the genetic material. Metal-induced genotoxicity has been attributed to indirect mechanisms, such as induction of oxidative stress and interference with DNA repair. Boron is a naturally occurring element and considered to be an essential micronutrient, although the cellular activities of boron compounds remain largely unexplored. The present study has been conducted to evaluate potential protective effects of boric acid (BA) against genotoxicity induced by cadmium chloride (CdCl2) and lead chloride (PbCl2) in V79 cell cultures. Cytotoxicity assays (neutral red uptake and cell titer blue assay) served to determine suitable concentrations for subsequent genotoxicity assays. Chromosomal damage and DNA strand breaks were assessed by micronucleus tests and comet assays. Both PbCl2 and CdCl2 (at 3, 5 and 10 µM) were shown to induce concentration-dependent increases in micronucleus frequencies and DNA strand breaks in V79 cells. BA itself was not cytotoxic (up to 300 µM) and showed no genotoxic effects. Pretreatment of cells with low levels of BA (2.5 and 10 µM) was found to strongly reduce the genotoxic effects of the tested metals. Based on the findings of this in vitro study, it can be suggested that boron provides an efficient protection against the induction of DNA strand breaks and micronuclei by lead and cadmium. Further studies on the underlying mechanisms for the protective effect of boron are needed.

Combination of physico-chemical analysis, Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay/nuclear abnormalities tests for cyto-genotoxicity assessments of treated effluents discharged from textile industries.

PubMed

Hemachandra, Chamini K; Pathiratne, Asoka

2016-09-01

Bioassays for cyto-genotoxicity assessments are generally not required in current textile industry effluent discharge management regulations. The present study applied in vivo plant and fish based toxicity tests viz. Allium cepa test system and Oreochromis niloticus erythrocyte based comet assay and nuclear abnormalities tests in combination with physico-chemical analysis for assessing potential cytotoxic/genotoxic impacts of treated textile industry effluents reaching a major river (Kelani River) in Sri Lanka. Of the treated effluents tested from two textile industries, color in the Textile industry 1 effluents occasionally and color, biochemical oxygen demand and chemical oxygen demand in the Textile industry 2 effluents frequently exceeded the specified Sri Lankan tolerance limits for discharge of industrial effluents into inland surface waters. Exposure of A. cepa bulbs to 100% and 12.5% treated effluents from both industries resulted in statistically significant root growth retardation, mito-depression, and induction of chromosomal abnormalities in root meristematic cells in comparison to the dilution water in all cases demonstrating cyto-genotoxicity associated with the treated effluents. Exposure of O. niloticus to the 100% and 12.5% effluents, resulted in erythrocytic genetic damage as shown by elevated total comet scores and induction of nuclear abnormalities confirming the genotoxicity of the treated effluents even with 1:8 dilution. The results provide strong scientific evidence for the crucial necessity of incorporating cyto-genotoxicity impact assessment tools in textile industry effluent management regulations considering human health and ecological health of the receiving water course under chronic exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of Genotoxic and Cytotoxic Effects in Human Peripheral Blood Lymphocytes Exposed In Vitro to Neonicotinoid Insecticides News

PubMed Central

Calderón-Segura, María Elena; Gómez-Arroyo, Sandra; Villalobos-Pietrini, Rafael; Martínez-Valenzuela, Carmen; Carbajal-López, Yolanda; Calderón-Ezquerro, María del Carmen; Cortés-Eslava, Josefina; García-Martínez, Rocío; Flores-Ramírez, Diana; Rodríguez-Romero, María Isabel; Méndez-Pérez, Patricia; Bañuelos-Ruíz, Enrique

2012-01-01

Calypso (thiacloprid), Poncho (clothianidin), Gaucho (imidacloprid), and Jade (imidacloprid) are commercial neonicotinoid insecticides, a new class of agrochemicals in México. However, genotoxic and cytotoxic studies have not been performed. In the present study, human peripheral blood lymphocytes (PBL) were exposed in vitro to different concentrations of the four insecticides. The genotoxic and cytotoxic effects were evaluated using the alkaline comet and trypan blue dye exclusion assays. DNA damage was evaluated using two genotoxicity parameters: tail length and comet frequency. Exposure to 9.5 × 10−6 to 5.7 × 10−5 M Jade; 2.8 × 10−4 to 1.7 × 10−3 M Gaucho; 0.6 × 10−1 to 1.4 × 10−1 M Calypso; 1.2 × 10−1 to 9.5 × 10−1 M Poncho for 2 h induced a significant increase DNA damage with a concentration-dependent relationship. Jade was the most genotoxic of the four insecticides studied. Cytotoxicity was observed in cells exposed to 18 × 10−3 M Jade, 2.0 × 10−3 M Gaucho, 2.0 × 10−1 M Calypso, 1.07 M Poncho, and cell death occurred at 30 × 10−3 M Jade, 3.3 × 10−3 M Gaucho, 2.8 × 10−1 M Calypso, and 1.42 M Poncho. This study provides the first report of genotoxic and cytotoxic effects in PBL following in vitro exposure to commercial neonicotinoid insecticides. PMID:22545045

Genotoxicity evaluation of carbon monoxide and 1, 3-butadiene using a new joint technology - the in vitro γH2AX HCS assay combined with air-liquid interface system.

PubMed

Zhang, Sen; Chen, Huan; Wang, An; Liu, Yong; Hou, Hongwei; Hu, Qingyuan

2018-05-21

To investigate the genotoxicity of gaseous toxicants CO and 1,3-butadiene in vitro, a novel combination technology-the in vitro γH2AX high content screening assay combined with air-liquid interface system was established. The results showed that this new technology was available and effective. Based on the joint technology, genotoxicity of CO and 1,3-butadiene was evaluated further in this study. The results showed that treatment concentrations (0, 20%,40%, 80% and 100%, v/v) and exposure time (15, 30, 45, 60 and 90 min) of CO both had no statistically significant effects on the induction of γH2AX (p > 0.05). However, 1,3-butadiene can induce significant γH2AX (p < 0.01) in A549 cells in a dose/time-dependent manner both in the absence and presence of rat liver S9. When the concentrations of 1,3-butadiene were more than 80%, a higher γH2AX level could be induced than the 1.5-fold of vehicle controls after 1 h of treatment. Overall, this new technology can be used a complementary tool to evaluate the genotoxicity of airborne toxicants in vitro based on the in vitro γH2AX high content screening assay combined with air-liquid interface system. Based on the joint technology, CO was not genotoxic in A549 cells, while 1,3-butadiene showed significant genotoxicity in the dose/time-dependency on the induction of γH2AX.

In vivo genotoxicity assessment of titanium, zirconium and aluminium nanoparticles, and their microparticulated forms, in Drosophila.

PubMed

Demir, Eşref; Turna, Fatma; Vales, Gerard; Kaya, Bülent; Creus, Amadeu; Marcos, Ricard

2013-11-01

As in vivo system, we propose Drosophila melanogaster as a useful model for study the genotoxic risks associated with nanoparticle exposure. In this study we have carried out a genotoxic evaluation of titanium dioxide (TiO2), zirconium oxide (ZrO2) and aluminium oxide (Al2O3) nanoparticles and their microparticulated forms in D. melanogaster by using the wing somatic mutation and recombination assay. This assay is based on the principle that loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs and flare-3, can lead to the formation of mutant clones in treated larvae, which are expressed as mutant spots on the wings of adult flies. Third instar larvae were feed with TiO2, ZrO2 and Al2O3 nanoparticles, and their microparticulated forms, at concentrations ranging from 0.1 to 10mM. Although a certain level of aggregation/agglomeration was observed in solution, it must be noted than the constant digging activity of larvae ensures that treated medium pass constantly through the digestive tract ensuring exposure. The results showed that no significant increases in the frequency of all spots (e.g. small single, large single, twin, total mwh and total spots) were observed, indicating that these nanoparticles were not able to induce genotoxic activity in the wing spot assay of D. melanogaster. Negative data were also obtained with the microparticulated forms. This indicates that the nanoparticulated form of the selected nanomaterials does not modify the potential genotoxicity of their microparticulated versions. These in vivo results contribute to increase the genotoxicity database on the TiO2, ZrO2 and Al2O3 nanoparticles. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cytotoxic and genotoxic characterization of aluminum and silicon oxide nanoparticles in macrophages.

PubMed

Hashimoto, Masanori; Imazato, Satoshi

2015-05-01

Although aluminum oxide and silicon oxide nanoparticles are currently available as dental materials, there is a lack of basic information concerning their biocompatibility. This study evaluates the biological responses of cultured macrophages (RAW264) to aluminum oxide (Al2O3NPs) and silicon oxide nanoparticles (SiO2NPs) by analyzing cytotoxicity and genotoxicity. The nanoparticles are amorphous and spherical, with diameters of 13 nm for the Al2O3NPs and 12 nm for the SiO2NPs. The cultured RAW264 are exposed to the nanoparticles (NPs) and examined for cytotoxicity using the WST-8 cell viability and Hoechst/PI apoptosis assay, for genotoxicity by micronucleus analysis, for changes in nuclear shape (deformed nuclei) and for comet assay using confocal microscopy, and micromorphological analysis is done using scanning and transmission electron microscopes. Nuclei and DNA damage because of exposure to both types of NPs is observed by inmunostaining genotoxicity testing. The cytotoxicity and genotoxicity are well correlated in this study. Numerous NPs are observed as large aggregates in vesicles, but less or nonexistent NP internalization is seen in the nucleus or cytoplasm. These morphological results suggest that a primary cause of cell disruption is the chemical changes of the NPs in the low pH of vesicles (i.e., ionization of Al2O3 or SiO2) for both types of oxide NPs. Although further research on the elution of NP concentrations on cell or tissue activity under simulated clinical conditions is required, NP concentrations over 200 μg/mL are large enough to induce cytotoxic and genotoxic effects to cells. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

No evidence of the genotoxic potential of gold, silver, zinc oxide and titanium dioxide nanoparticles in the SOS chromotest.

PubMed

Nam, Sun-Hwa; Kim, Shin Woong; An, Youn-Joo

2013-10-01

Gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), zinc oxide nanoparticles (ZnO NPs) and titanium dioxide nanoparticles (TiO2 NPs) are widely used in cosmetic products such as preservatives, colorants and sunscreens. This study investigated the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest with Escherichia coli PQ37. The maximum exposure concentrations for each nanoparticle were 3.23 mg l(-1) for Au NPs, 32.3 mg l(-1) for Ag NPs and 100 mg l(-1) for ZnO NPs and TiO2 NPs. Additionally, in order to compare the genotoxicity of nanoparticles and corresponding dissolved ions, the ions were assessed in the same way as nanoparticles. The genotoxicity of the titanium ion was not assessed because of the extremely low solubility of TiO2 NPs. Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn, in a range of tested concentrations, exerted no effects in the SOS chromotest, evidenced by maximum IF (IFmax) values of below 1.5 for all chemicals. Owing to the results, nanosized Au NPs, Ag NPs, ZnO NPs, TiO2 NPs and ions of Au, Ag and Zn are classified as non-genotoxic on the basis of the SOS chromotest used in this study. To the best of our knowledge, this is the first study to evaluate the genotoxicity of Au NPs, Ag NPs, ZnO NPs and TiO2 NPs using the SOS chromotest. Copyright © 2012 John Wiley & Sons, Ltd.

The development of GADD45α luciferase reporter assays in human cells for assessing the genotoxicity of environmental pollutants.

PubMed

Xin, Lili; Wang, Jianshu; Wu, Yanhu; Guo, Sifan

2015-02-01

In order to assess the potential carcinogenic and genotoxic responses induced by environmental pollutants, genotoxicity test systems based on a GADD45α promoter-driven luciferase reporter in human A549 and HepG2 cells were established. Four different types of environmental toxicants including DNA alkylating agents, precarcinogenic agents, DNA cross-linking agents and non-carcinogenic agents, and three environmental samples collected from a coke oven plant were used to evaluate the test systems. After treated with the tested agents and environmental samples for 12 h, the cell viabilities and luciferase activities of the luciferase reporter cells were determined, respectively. Methyl methanesulfonate, benzo[a]pyrene, formaldehyde and the extractable organic matter (EOM) from coke oven emissions in ambient air generally produced significant induction of relative luciferase activity in a similar dose-dependent manner in A549- and HepG2-luciferase cells. No significant increases in relative luciferase activity were observed in pyrene-treated A549- or HepG2-luciferase cells. Significant increase in relative luciferase activity was already evident after 2.5 µM benzo[a]pyrene, 5 µM formaldehyde, 0.006 µg/L bottom-EOM, 0.10 µg/L side-EOM or 0.06 µg/L top-EOM, where no cytotoxic damage was observed. Compared with the A549-luciferase cells, the tested pollutants produced higher induction of relative luciferase activity in HepG2-luciferase cells. Therefore, the new genotoxicity test systems can detect different types of genotoxic agents and low concentrations of environmental samples. The luciferase reporter cells, especially the HepG2-luciferase cells, could provide a valuable tool for rapid screening of the genotoxic damage of environmental pollutants and their complex mixtures.

Ground and Surface Water for Drinking: A Laboratory Study on Genotoxicity Using Plant Tests

PubMed Central

Feretti, Donatella; Ceretti, Elisabetta; Gustavino, Bianca; Zerbini, llaria; Zani, Claudia; Monarca, Silvano; Rizzoni, Marco

2012-01-01

Surface waters are increasingly utilized for drinking water because groundwater sources are often polluted. Several monitoring studies have detected the presence of mutagenicity in drinking water, especially from surface sources due to the reaction of natural organic matter with disinfectant. The study aimed to investigate the genotoxic potential of the products of reaction between humic substances, which are naturally present in surface water, and three disinfectants: chlorine dioxide, sodium hypochlorite and peracetic acid. Commercial humic acids dissolved in distilled water at different total organic carbon (TOC) concentrations were studied in order to simulate natural conditions of both ground water (TOC=2.5 mg/L) and surface water (TOC=7.5 mg/L). These solutions were treated with the biocides at a 1:1 molar ratio of C:disinfectant and tested for genotoxicity using the anaphase chromosomal aberration and micronucleus tests in Allium cepa, and the Vicia faba and Tradescantia micronucleus tests. The tests were carried out after different times and with different modes of exposure, and at 1:1 and 1:10 dilutions of disinfected and undisinfected humic acid solutions. A genotoxic effect was found for sodium hypochlorite in all plant tests, at both TOCs considered, while chlorine dioxide gave positive results only with the A.cepa tests. Some positive effects were also detected for PAA (A.cepa and Tradescantia). No relevant differences were found in samples with different TOC values. The significant increase in all genotoxicity end-points induced by all tested disinfectants indicates that a genotoxic potential is exerted even in the presence of organic substances at similar concentrations to those frequently present in drinking water. PMID:25170443

Aspect ratio has no effect on genotoxicity of multi-wall carbon nanotubes.

PubMed

Kim, Jin Sik; Lee, Kyu; Lee, Young Hee; Cho, Hyun Sun; Kim, Ki Heon; Choi, Kyung Hee; Lee, Sang Hee; Song, Kyung Seuk; Kang, Chang Soo; Yu, Il Je

2011-07-01

Carbon nanotubes (CNTs) have specific physico-chemical and electrical properties that are useful for telecommunications, medicine, materials, manufacturing processes and the environmental and energy sectors. Yet, despite their many advantages, it is also important to determine whether CNTs may represent a hazard to the environment and human health. Like asbestos, the aspect ratio (length:diameter) and metal components of CNTs are known to have an effect on the toxicity of carbon nanotubes. Thus, to evaluate the toxic potential of CNTs in relation to their aspect ratio and metal contamination, in vivo and in vitro genotoxicity tests were conducted using high-aspect-ratio (diameter: 10-15 nm, length: ~10 μm) and low-aspect-ratio multi-wall carbon nanotubes (MWCNTs, diameter: 10-15 nm, length: ~150 nm) according to OECD test guidelines 471 (bacterial reverse mutation test), 473 (in vitro chromosome aberration test), and 474 (in vivo micronuclei test) with a good laboratory practice system. To determine the treatment concentration for all the tests, a solubility and dispersive test was performed, and a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) solution found to be more suitable than distilled water. Neither the high- nor the low-aspect-ratio MWCNTs induced any genotoxicity in a bacterial reverse mutation test (~1,000 μg/plate), in vitro chromosome aberration test (without S9: ~6.25 μg/ml, with S9: ~50 μg/ml), or in vivo micronuclei test (~50 mg/kg). However, the high-aspect-ratio MWCNTs were found to be more toxic than the low-aspect-ratio MWCNTs. Thus, while high-aspect-ratio MWCNTs do not induce direct genotoxicity or metabolic activation-mediated genotoxicity, genotoxicity could still be induced indirectly through oxidative stress or inflammation.

Pro-oxidant Induced DNA Damage in Human Lymphoblastoid Cells: Homeostatic Mechanisms of Genotoxic Tolerance

PubMed Central

Seager, Anna L.

2012-01-01

Oxidative stress contributes to many disease etiologies including ageing, neurodegeneration, and cancer, partly through DNA damage induction (genotoxicity). Understanding the i nteractions of free radicals with DNA is fundamental to discern mutation risks. In genetic toxicology, regulatory authorities consider that most genotoxins exhibit a linear relationship between dose and mutagenic response. Yet, homeostatic mechanisms, including DNA repair, that allow cells to tolerate low levels of genotoxic exposure exist. Acceptance of thresholds for genotoxicity has widespread consequences in terms of understanding cancer risk and regulating human exposure to chemicals/drugs. Three pro-oxidant chemicals, hydrogen peroxide (H2O2), potassium bromate (KBrO3), and menadione, were examined for low dose-response curves in human lymphoblastoid cells. DNA repair and antioxidant capacity were assessed as possible threshold mechanisms. H2O2 and KBrO3, but not menadione, exhibited thresholded responses, containing a range of nongenotoxic low doses. Levels of the DNA glycosylase 8-oxoguanine glycosylase were unchanged in response to pro- oxidant stress. DNA repair–focused gene expression arrays reported changes in ATM and BRCA1, involved in double-strand break repair, in response to low-dose pro-oxidant exposure; however, these alterations were not substantiated at the protein level. Determination of oxidatively induced DNA damage in H2O2-treated AHH-1 cells reported accumulation of thymine glycol above the genotoxic threshold. Further, the H2O2 dose-response curve was shifted by modulating the antioxidant glutathione. Hence, observed pro- oxidant thresholds were due to protective capacities of base excision repair enzymes and antioxidants against DNA damage, highlighting the importance of homeostatic mechanisms in “genotoxic tolerance.” PMID:22539617

State of the Art High-Throughput Approaches to Genotoxicity: Flow Micronucleus, Ames II, GreenScreen and Comet

EPA Pesticide Factsheets

State of the Art High-Throughput Approaches to Genotoxicity: Flow Micronucleus, Ames II, GreenScreen and Comet (Presented by Dr. Marilyn J. Aardema, Chief Scientific Advisor, Toxicology, Dr. Leon Stankowski, et. al. (6/28/2012)

GENOTOXICITY STUDIES OF SODIUM DICHLOROACETATE AND SODIUM TRICHLOROACETATE

EPA Science Inventory

The genotoxic properties of sodium dichloroacetate (DCA) and sodium trichloroacetate (TCA)were evaluated in several short-term in vitro and in vivo assays. Neither compound was mutagenic in tester strain TA102 in the Salmonella mutagenicity assay. Both DCA and TCA were weak induc...

MICROBIAL GENOTOXICITY AS AN ENVIRONMENTAL INDICATOR FOR NEAR-COASTAL SEDIMENT PORE WATERS

EPA Science Inventory

Lewis, Michael A., Carol. B. Daniels and Cynthia A. Chancy. Submitted. The genotoxic potential of environmental media collected from coastal areas impacted by anthropogenic contaminants has not been reported frequently in the scientific literature, particularly in the Gulf of Mex...

METABOLISM, MICROFLORA EFFECTS, AND GENOTOXICITY IN HALOACETIC ACID-TREATED CULTURES OF RAT CECAL MICROBIOTA

EPA Science Inventory

Haloacetic acids are by-products of drinking water disinfection. Several compounds in this class are genotoxic and have been identified as rodent hepatocarcinogens. Enzymes produced by the normal intestinal bacteria can transform some promutagens and procarcinogens to their bio...

COMPARATIVE GENOTOXIC RESPONSES TO ARSENITE IN GUINEA PIG, MOUSE, RAT AND HUMAN LYMPHOCYTES

EPA Science Inventory

Comparative genotoxic responses to arsenite in guinea pig, mouse, rat and human
lymphocytes.

Inorganic arsenic is a known human carcinogen causing skin, lung, and bladder cancer following chronic exposures. Yet, long-term laboratory animal carcinogenicity studies have ...

Evaluating ToxCast Assays for their Ability to Detect Genotoxicity

EPA Science Inventory

It has become evident over the past several decades, that though the standard battery of genotoxicity tests including bacterial and in vitro mammalian mutagenesis and in vitro and in vivo clastogenicity assays have been quite useful in screening out potent genotoxicants during th...

SOIL REDUCES 2,4,6-TRINITROTOLUENE BIOAVAILABILITY AND GENOTOXICITY IN VIVO

EPA Science Inventory

Soil Reduces 2,4,6- Trinitrotoluene Bioavailability and Genotoxicity In Vivo

As chemicals age in soil, irreversible binding of chemical contaminants to organic components in the soil may occur, impacting the amount of chemical that is biologically available upon exp...

The Genotoxicity of Titanium Dioxide and Cerium Dioxide Nanoparticles in Human Respiratory Epithelial Cells

EPA Science Inventory

Due to the exponential growth of the nanomaterial industry, risk assessment of human exposure to nanomaterials in consumer products is of paramount importance. The genotoxicity of nanomaterials is an important aspect of hazard identification and regulatory guidance. However, this...

Genotoxic Effects of Titanium Dioxide and Cerium Dioxide Nanoparticles in Human Respiratory Epithelial Cells

EPA Science Inventory

The nanomaterial industry has recently seen rapid growth, therefore, the risk assessment of human exposure to nanomaterials in consumer products is of paramount importance. The genotoxicity of nanomaterials is a fundamental aspect of hazard identification and regulatory guidance....

Assessment of the Microscreen phage-induction assay for screening hazardous wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Houk, V.S.; DeMarini, D.M.

1987-09-01

The Microscreen phage-induction assay, which quantitatively measures the induction of prophage lambda in Escherichia coli WP2s(lambda), was used to test 14 crude (unfractionated) hazardous industrial waste samples for genotoxic activity in the presence and absence of metabolic activation. Eleven of the 14 wastes induced prophage, and induction was observed at concentrations as low as 0.4 picograms per ml. Comparisons between the mutagenicity of these waste samples in Salmonella and their ability to induce prophage lambda indicate that the Microscreen phage-induction assay detected genotoxic activity in all but one of the wastes that were mutagenic in Salmonella. Moreover, the Microscreen assaymore » detected as genotoxic 5 additional wastes that were not detected in the Salmonella assay. The applicability of the Microscreen phage-induction assay for screening hazardous wastes for genotoxic activity is discussed along with some of the problems associated with screening highly toxic wastes containing toxic volatile compounds.« less

Randomly amplified polymorphic-DNA analysis for detecting genotoxic effects of Boron on maize (Zea mays L.).

PubMed

Sakcali, M Serdal; Kekec, Guzin; Uzonur, Irem; Alpsoy, Lokman; Tombuloglu, Huseyin

2015-08-01

This study was carried out to investigate the genotoxic effect of boron (B) on maize using randomly amplified polymorphic DNA (RAPD) method. Experimental design was conducted under 0, 5, 10, 25, 50, 100, 125, and 150 ppm B exposures, and physiological changes have revealed a sharp decrease in root growth rates from 28% to 85%, starting from 25 ppm to 150 ppm, respectively. RAPD-polymerase chain reaction (PCR) analysis shows that DNA alterations are clearly observed from beginning to 100 ppm. B-induced inhibition in root growth had a positive correlation with DNA alterations. Total soluble protein, root and stem lengths, and B content analysis in root and leaves encourage these results as a consequence. These preliminary findings reveal that B causes chromosomal aberration and genotoxic effects on maize. Meanwhile, usage of RAPD-PCR technique is a suitable biomarker to detect genotoxic effect of B on maize and other crops for the future. © The Author(s) 2013.

Assessment of the in vivo genotoxicity of cadmium chloride, chloroform, and D,L-menthol as coded test chemicals using the alkaline comet assay.

PubMed

Wada, Kunio; Fukuyama, Tomoki; Nakashima, Nobuaki; Matsumoto, Kyomu

2015-07-01

As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM) international validation study of in vivo rat alkaline comet assays, we examined cadmium chloride, chloroform, and D,L-menthol under blind conditions as coded chemicals in the liver and stomach of Sprague-Dawley rats after 3 days of administration. Cadmium chloride showed equivocal responses in the liver and stomach, supporting previous reports of its poor mutagenic potential and non-carcinogenic effects in these organs. Treatment with chloroform, which is a non-genotoxic carcinogen, did not induce DNA damage in the liver or stomach. Some histopathological changes, such as necrosis and degeneration, were observed in the liver; however, they did not affect the comet assay results. D,L-Menthol, a non-genotoxic non-carcinogen, did not induce liver or stomach DNA damage. These results indicate that the comet assay can reflect genotoxic properties under blind conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

Eco- and genotoxicity profiling of a rapeseed biodiesel using a battery of bioassays.

PubMed

Eck-Varanka, Bettina; Kováts, Nora; Horváth, Eszter; Ferincz, Árpád; Kakasi, Balázs; Nagy, Szabolcs Tamás; Imre, Kornélia; Paulovits, Gábor

2018-04-30

Biodiesel is considered an important renewable energy source but still there is some controversy about its environmental toxicity, especially to aquatic life. In our study, the toxicity of water soluble fraction of biodiesel was evaluated in relatively low concentrations using a battery of bioassays: Vibrio fischeri bioluminescence inhibition, Sinapis alba root growth inhibition, Daphnia magna immobilization, boar semen live/dead ratio and DNA fragmentation and Unio pictorum micronucleus test. While the S. alba test indicated nutritive (stimulating) effect of the sample, the biodiesel exerted toxic effect in the aquatic tests. D. magna was the most sensitive with EC 50 value of 0.0226%. For genotoxicity assessment, the mussel micronucleus test (MNT) was applied, detecting considerable genotoxic potential of the biodiesel sample: it elucidated micronuclei formation already at low concentration of 3.3%. Although this test has never been employed in biodiesel eco/genotoxicity assessments, it seems a promising tool, based on its appropriate sensitivity, and representativity. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of MPS1 Inhibition on Genotoxic Stress Responses in Murine Tumour Cells.

PubMed

Suzuki, Motofumi; Yamamori, Tohru; Yasui, Hironobu; Inanami, Osamu

2016-06-01

The monopolar spindle 1 (MPS1) is a serine/threonine kinase that plays an important role in spindle assembly checkpoint signaling. To determine the possible relationship between MPS1 inhibition and genotoxic stress responses, herein we examined whether MPS1 inhibition influences cellular susceptibility towards two genotoxic treatments, etoposide and ionizing radiation (IR). Two murine tumour cell lines, SCCVII and EMT6, were used. The effect of genotoxic treatments with or without two novel MPS1 inhibitors, NMS-P715 and AZ3146, on cellular survival, cell-cycle distribution, centrosome status and mitotic catastrophe (MC) was evaluated. MPS1 inhibition sensitized murine tumour cells to etoposide but not to IR. In addition, MPS1 inhibition altered cell-cycle progression and exacerbated centrosome abnormalities, resulting in enhanced MC induced by etoposide but not by IR. MPS1 inhibition promotes the etoposide-induced aberrant mitosis and, consequently, the induction of tumour cell death. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Regulatory requirements for genotoxicity assessment of plant protection product active ingredients, impurities, and metabolites.

PubMed

Booth, Ewan D; Rawlinson, Paul J; Maria Fagundes, Priscila; Leiner, Kevin A

2017-06-01

Active ingredients in plant protection products are subject to rigorous safety assessment during their development, including assessment of genotoxicity. Plant protection products are used for agriculture in multiple regions and for the registration of active ingredients it is necessary to satisfy the data requirements of these different regions. There are no overarching global agreements on which genotoxicity studies need to be conducted to satisfy the majority of regulatory authorities. The implementation of new OECD guidelines for the in vitro micronucleus, transgenic rodent somatic and germ cell gene mutation and in vivo comet assays, as well as the revision of a number of other OECD test guidelines has resulted in some changes to data requirements. This review describes the genotoxicity data requirements for chemical active ingredients as well as biologicals, microbials, ground water metabolites, metabolites, and impurities in a number of regions. Similarities and differences are highlighted. Environ. Mol. Mutagen. 58:325-344, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Ecotoxicological and genotoxic assessment of hospital laundry wastewaters.

PubMed

Kern, Deivid Ismael; Schwaickhardt, Rômulo de Oliveira; Lutterbeck, Carlos Alexandre; Kist, Lourdes Teresinha; Alcayaga, Eduardo Alexis Lobo; Machado, Ênio Leandro

2015-01-01

The aim of the present study was to assess the ecotoxicity and genotoxicity of hospital laundry wastewaters generated from a regional hospital located in Rio Pardo Valley in the state of Rio Grande do Sul, Brazil. Physicochemical, microbiological, ecotoxicological, and genotoxic analyses were performed, and the results indicate that some parameters were not in accordance with the limit concentrations established by Brazilian and international guidelines for urban wastewaters. Daphnia magna (EC50 2.01%) and Danio rerio (LC50 29.25%) acute toxicity was detected, and sublethal effects were identified in Lactuca sativa (IC25 12.50%) and Allium cepa (IC25 51.25%). Cytotoxicity was observed at the five wastewater concentrations used yielding statistically significant differences (p < 0.05) in the meristematic cells of A. cepa compared with the negative control. The results obtained here warn about the necessity to develop treatment methods that can mitigate the environmental impacts caused by the ecotoxicity and genotoxicity of hospital laundry wastewaters.

In situ assessment of pesticide genotoxicity in an integrated pest management program: II. Maize waxy mutation assay.

PubMed

Rodrigues, G S; Pimentel, D; Weinstein, L H

1998-02-13

The mutagenicity induced by pesticides applied in an integrated pest management (IPM) program was evaluated in situ with the maize forward waxy mutation bioassay. Three pesticide application rates were prescribed as follows: (1) Low--no field pesticide spray; (2) Medium--IPM test rate: banded cyanazine plus metolachlor (2.7 kg a.i. and 2.3 l a.i./ha of herbicides, respectively); and (3) High--a preventative pesticide application program: broadcast cyanazine plus metolachlor (same application rates as above) plus chlorpyrifos (1 kg a.i./ha of insecticide). In general, there was no significant reduction in the genotoxic effects from the high to the medium treatment levels of the IPM program. This suggests that the reduction in pesticide application rates attained with the implementation of the proposed IPM program was not sufficient to abate the genotoxicity of the pesticides. The results indicate that replacing genotoxic compounds may be the only effective remediation measure if concern about environmental mutagenesis were to result in changes in agricultural management.

Assessment of global and gene-specific DNA methylation in rat liver and kidney in response to non-genotoxic carcinogen exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozden, Sibel, E-mail: stopuz@istanbul.edu.tr; Turgut Kara, Neslihan; Sezerman, Osman Ugur

Altered expression of tumor suppressor genes and oncogenes, which is regulated in part at the level of DNA methylation, is an important event involved in non-genotoxic carcinogenesis. This may serve as a marker for early detection of non-genotoxic carcinogens. Therefore, we evaluated the effects of non-genotoxic hepatocarcinogens, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), hexachlorobenzene (HCB), methapyrilene (MPY) and male rat kidney carcinogens, d-limonene, p-dichlorobenzene (DCB), chloroform and ochratoxin A (OTA) on global and CpG island promoter methylation in their respective target tissues in rats. No significant dose-related effects on global DNA hypomethylation were observed in tissues of rats compared to vehicle controls using LC–MS/MSmore » in response to short-term non-genotoxic carcinogen exposure. Initial experiments investigating gene-specific methylation using methylation-specific PCR and bisulfite sequencing, revealed partial methylation of p16 in the liver of rats treated with HCB and TCDD. However, no treatment related effects on the methylation status of Cx32, e-cadherin, VHL, c-myc, Igfbp2, and p15 were observed. We therefore applied genome-wide DNA methylation analysis using methylated DNA immunoprecipitation combined with microarrays to identify alterations in gene-specific methylation. Under the conditions of our study, some genes were differentially methylated in response to MPY and TCDD, whereas d-limonene, DCB and chloroform did not induce any methylation changes. 90-day OTA treatment revealed enrichment of several categories of genes important in protein kinase activity and mTOR cell signaling process which are related to OTA nephrocarcinogenicity. - Highlights: • Studied non-genotoxic carcinogens caused no change on global DNA hypomethylation. • d-Limonene, DCB and chloroform did not show any genome-wide methylation changes. • Some genes were differentially methylated in response to MPY, TCDD and OTA. • Protein kinase activity and mTOR cell signaling are involved in OTA carcinogenicity. • Our data highlight Cpne4 may be a potential biomarker for non-genotoxic carcinogens.« less

Linking embryo toxicity with genotoxic responses in the freshwater snail Physa acuta: single exposure to benzo(a)pyrene, fluoxetine, bisphenol A, vinclozolin and exposure to binary mixtures with benzo(a)pyrene.

PubMed

Sánchez-Argüello, Paloma; Aparicio, Natalia; Fernández, Carlos

2012-06-01

Genotoxic effects on fauna after waterborne pollutant exposure have been demonstrated by numerous research programmes. Less effort has been focused on establishing relationship between genotoxicity and long-term responses at higher levels of biological organization. Taking into account that embryos may be more sensitive indicators of reproductive impairment than alterations in fertility, we have developed two assays in multiwell plates to address correlations between embryo toxicity and genotoxicity. The potential teratogenicity was assessed by analyzing abnormal development and mortality of Physa acuta at embryonic stage. Genotoxicity was measured by the micronucleus (MN) test using embryonic cells. Our results showed that linkage between genotoxicity and embryo toxicity depends on mechanisms of action of compounds under study. Embryo toxic responses showed a clear dose-related tendency whereas no clear dose-dependent effect was observed in micronucleus induction. The higher embryo toxicity was produced by benzo(a)pyrene exposure followed by fluoxetine and bisphenol A. Vinclozolin was the lower embryo toxic compound. Binary mixtures with BaP always resulted in higher embryo toxicity than single exposures but antagonistic effects were observed for MN induction. Benzo(a)pyrene produced the higher MN induction at 0.04 mg/L, which also produced clear embryo toxic effects. Fluoxetine did not induce cytogenetic effects but 0.25mg/L altered embryonic development. Bisphenol A significantly reduced hatchability at 0.5mg/L while MN induction appeared with higher treatments than those that start causing teratogenicity. Much higher concentration of vinclozolin (5mg/L) reduced hatchability and induced maximum MN formation. In conclusion, while validating one biomarker of genotoxicity and employing one ecologically relevant effect, we have evaluated the relative sensitivity of a freshwater mollusc for a range of chemicals. The embryo toxicity test is a starting point for the development of a life cycle test with freshwater snails even for undertaking multigeneration studies focused on transgenerational effects. Copyright © 2012 Elsevier Inc. All rights reserved.

Synthesis and characterization of silver nanoparticles using Caesalpinia pulcherrima flower extract and assessment of their in vitro antimicrobial, antioxidant, cytotoxic, and genotoxic activities.

PubMed

Moteriya, Pooja; Chanda, Sumitra

2017-12-01

Caesalpinia pulcherrima flower extract mediated synthesis of silver nanoparticles was attempted in the present work including optimization of some procedure parameters. Characterization of synthesized silver nanoparticles was done by various spectral analyses. The size of synthesized silver nanoparticles was 12 nm and they were spherical in shape. The green synthesized silver nanoparticles were further evaluated for antimicrobial, antioxidant, cytotoxic, and genotoxic activities; they showed good antimicrobial, antioxidant, and cytotoxic effects. Genotoxic study revealed non-toxic nature at lower concentration. Overall results suggest that the synthesized silver nanoparticles have pronounced applicability in pharmaceutical and biomedical field.

Method for protection against genotoxic mutagenesis

DOEpatents

Grdina, David J.

1996-01-01

A method and pharmaceutical for protecting against genotoxic damage in irradiated cells. Reduction of mutations at the hypoxanthine-guanine phosphoribosyl transferase locus is accomplished by administering an effective dose of a compound having protected sulfhydryl groups which metabolize in vivo to produce both free sulfhydryl groups and disulfides.

High Throughput Genotoxicity Profiling of the US EPA ToxCast Chemical Library

EPA Science Inventory

A key aim of the ToxCast project is to investigate modern molecular and genetic high content and high throughput screening (HTS) assays, along with various computational tools to supplement and perhaps replace traditional assays for evaluating chemical toxicity. Genotoxicity is a...

MAMMALIAN CELL CYTOTOXICITY AND GENOTOXICITY OF NEW DRINKING WATER DISINFECTION BY-PRODUCTS

EPA Science Inventory

The disinfection of drinking water continues to protect the public health against acute disease. Drinking water disinfection by-products (DBPs) are formed by the reaction of a disinfectant with naturally occurring organic matter. Many DBPs are genotoxic and are implicated as huma...

Evaluation of genotoxic effects of surface waters using a battery of bioassays indicating different mode of action.

PubMed

Han, Yingnan; Li, Na; Oda, Yoshimitsu; Ma, Mei; Rao, Kaifeng; Wang, Zijian; Jin, Wei; Hong, Gang; Li, Zhiguo; Luo, Yi

2016-11-01

With the burgeoning contamination of surface waters threatening human health, the genotoxic effects of surface waters have received much attention. Because mutagenic and carcinogenic compounds in water cause tumors by different mechanisms, a battery of bioassays that each indicate a different mode of action (MOA) is required to evaluate the genotoxic effects of contaminants in water samples. In this study, 15 water samples from two source water reservoirs and surrounding rivers in Shijiazhuang city of China were evaluated for genotoxic effects. Target chemical analyses of 14 genotoxic pollutants were performed according to the Environmental quality standards for surface water of China. Then, the in vitro cytokinesis-block micronucleus (CBMN) assay, based on a high-content screening technique, was used to detect the effect of chromosome damage. The SOS/umu test using strain TA1535/pSK1002 was used to detect effects on SOS repair of gene expression. Additionally, two other strains, NM2009 and NM3009, which are highly sensitive to aromatic amines and nitroarenes, respectively, were used in the SOS/umu test to avoid false negative results. In the water samples, only two of the genotoxic chemicals listed in the water standards were detected in a few samples, with concentrations that were below water quality standards. However, positive results for the CBMN assay were observed in two river samples, and positive results for the induction of umuC gene expression in TA1535/pSK1002 were observed in seven river samples. Moreover, positive results were observed for NM2009 with S9 and NM3009 without S9 in some samples that had negative results using the strain TA1535/pSK1002. Based on the results with NM2009 and NM3009, some unknown or undetected aromatic amines and nitroarenes were likely in the source water reservoirs and the surrounding rivers. Furthermore, these compounds were most likely the causative pollutants for the genotoxic effect of these water samples. Therefore, to identify causative pollutants with harmful biological effects, chemical analyses for the pollutants listed in water quality standards is not sufficient, and single-endpoint bioassays may underestimate adverse effects. Thus, a battery of bioassays based on different MOAs is required for the comprehensive detection of harmful biological effects. In conclusion, for genotoxicity screening of surface waters, the SOS/umu test system by using different strains combined with the CBMN assay was a useful approach. Copyright © 2016 Elsevier Inc. All rights reserved.

Comparative study of the mutagenic and genotoxic activity associated with inhalable particulate matter in Rio de Janeiro air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miguel, A.G.; Daisey, J.M.; Sousa, J.A.

1990-01-01

We have determined the genotoxic and mutagenic activities associated with inhalable particulate matter (IPM) collected in Rio de Janeiro, Brazil, Camden, NJ, and Caldecott Tunnel, CA, and used these results to compare three different bioassays. Samples collected every 12 hr (Rio) or every 24 hr (Camden) were extracted sequentially with cyclohexane (CX), dichloromethane (DCM), and acetone (ACE), for a rough fractionation by polarity, and composites of the extracts were tested for mutagenicity using the Salmonella frame shift (TA98) and base substitution (TA100) tester strains, as well as for genotoxicity using the Rossman Microscreen bioassay based on the induction of lambda-prophagemore » in a lysogenic Escherichia coli strain. All samples were tested without and with S9 metabolic activation. Maximum mutagenic and genotoxic activities were in the nonpolar (CX) and polar (ACE) fractions, respectively, indicating that these two assays detect different classes of compounds with different efficiencies. Oxidative aging of the Rio aerosol is indicated by a shift in activities in both tests from the less polar fractions in the day to the polar (ACE) fraction at night. The Rio TA98 mutagenic (18 rev/m3) and genotoxic (1.4 x 10(5) PFU/m3) activities were higher than those for Camden, an Eastern U.S. city, by factors of 1.4 and 2.8, respectively.« less

E2F1 transcription is induced by genotoxic stress through ATM/ATR activation.

PubMed

Carcagno, Abel L; Ogara, María F; Sonzogni, Silvina V; Marazita, Mariela C; Sirkin, Pablo F; Ceruti, Julieta M; Cánepa, Eduardo T

2009-05-01

E2F1, a member of the E2F family of transcription factors, plays a critical role in controlling both cell cycle progression and apoptotic cell death in response to DNA damage and oncogene activation. Following genotoxic stresses, E2F1 protein is stabilized by phosphorylation and acetylation driven to its accumulation. The aim of the present work was to examine whether the increase in E2F1 protein levels observed after DNA damage is only a reflection of an increase in E2F1 protein stability or is also the consequence of enhanced transcription of the E2F1 gene. The data presented here demonstrates that UV light and other genotoxics induce the transcription of E2F1 gene in an ATM/ATR dependent manner, which results in increasing E2F1 mRNA and protein levels. After genotoxic stress, transcription of cyclin E, an E2F1 target gene, was significantly induced. This induction was the result of two well-differentiated effects, one of them dependent on de novo protein synthesis and the other on the protein stabilization. Our results strongly support a transcriptional effect of DNA damaging agents on E2F1 expression. The results presented herein uncover a new mechanism involving E2F1 in response to genotoxic stress.

Physicochemical characteristics, mutagenicity and genotoxicity of airborne particles under industrial and rural influences in Northern Lebanon.

PubMed

Melki, Pamela N; Ledoux, Frédéric; Aouad, Samer; Billet, Sylvain; El Khoury, Bilal; Landkocz, Yann; Abdel-Massih, Roula M; Courcot, Dominique

2017-08-01

In this work, the main objectives were to assess the mutagenic and genotoxic effects of fine particulate matter collected in an industrial influenced site in comparison with a non-industrial influenced one (rural site) and to relate the particulate matter (PM) composition to the observed genotoxic effects. At the industrial influenced site, higher concentrations of phosphates, trace metals, and polycyclic aromatic hydrocarbons (PAHs) in particles could be related to the contributions of quarries, fertilizer producer, cement plants, and tires burning. Gasoline and diesel combustion contributions were evidenced in particles collected at both sites. Particles collected under industrial influence showed a higher mutagenic potential on three tested strains of Salmonella typhimurium (TA98, YG1041, and TA102), and especially on the YG1041, compared to particles from the rural site. Furthermore, only particles collected in the vicinity of the industrial site showed a tendency to activate the SOS responses in Escherichia coli PQ37, which is indicative of DNA damage as a result of exposure of the bacteria cells to the action of mutagenic samples. The mutagenicity and genotoxicity of the industrial PM 2.5-0.3 particulates may be attributed to its composition especially in organic compounds. This study showed that proximity of industries can affect local PM composition as well as PM genotoxic and mutagenic potential.

[Genotoxic damage among artisanal and small-scale mining workers exposed to mercury].

PubMed

Rosales-Rimache, Jaime A; Elizabeth Malca, Nancy; Alarcón, Jhonatan J; Chávez, Manuel; Gonzáles, Marco Antonio

2013-01-01

To determine the genotoxic damage among artisanal and small-scale mining workers exposed to mercury. Observational cross-sectional study which evaluated mercury-exposed workers (n=83), whose cells were collected by mouth swab for further staining, microscopic observance, micronuclei count, and other nuclear alterations. 24-hour urine was also collected for the determination of inorganic mercury. 68.7% of participants were male, the mean age being 43 ± 12,4 years (range: 16-76). The average time of occupational exposure to mercury was 12,1 ± 6,7 years, and the contact with mercury was 4,1 ± 3,6 kg per person per day. 93% of participants failed to wear personal protection gear while handling mercury. Results of biological monitoring showed that 17% of participants had concentrations of mercury in urine higher than 2,5 µg/L, this value being the detection limit of the measurement technique used. Results of the genotoxic evaluation evidenced that 15% of people with labor exposure to mercury presented micronuclei in mouth epithelial cells, and other indicators of nuclear alteration such as nucleoplasmic bridges, gemmation and binucleation were found, which are also considered genotoxic events associated to the exposure of physical or chemical risk agents. The finding of micronuclei in mouth epithelial cells reflects genotoxic damage associated to the labor exposure of mercury used in artisanal and small-scale mining activities.

Determination of spectral markers of cytotoxicity and genotoxicity using in vitro Raman microspectroscopy: cellular responses to polyamidoamine dendrimer exposure.

PubMed

Efeoglu, Esen; Casey, Alan; Byrne, Hugh J

2017-10-09

Although consumer exposure to nanomaterials is ever increasing, with potential increased applications in areas such as drug and/or gene delivery, contrast agents and diagnosis, the determination of the cyto- and geno-toxic effects of nanomaterials on human health and the environment still remains challenging. Although many techniques have been established and adapted to determine the cytotoxicity and genotoxicity of nano-sized materials, these techniques remain limited by the number of assays required, total cost, and use of labels and they struggle to explain the underlying interaction mechanisms. In this study, Raman microspectroscopy is employed as an in vitro label-free, high content screening technique to observe toxicological changes within the cell in a multi-parametric fashion. The evolution of spectral markers as a function of time and applied dose has been used to elucidate the mechanism of action of polyamidoamine (PAMAM) dendrimers associated with cytotoxicity and their impact on nuclear biochemistry. PAMAM dendrimers are chosen as a model nanomaterial due to their widely studied cytotoxic and genotoxic properties and commercial availability. Point spectra were acquired from the cytoplasm to monitor the cascade of toxic events occurring in the cytoplasm upon nanoparticle exposure, whereas the spectra acquired from the nucleus and the nucleolus were used to explore PAMAM-nuclear material interaction as well as genotoxic responses.

Cytostatic and genotoxic effect of temephos in human lymphocytes and HepG2 cells.

PubMed

Benitez-Trinidad, A B; Herrera-Moreno, J F; Vázquez-Estrada, G; Verdín-Betancourt, F A; Sordo, M; Ostrosky-Wegman, P; Bernal-Hernández, Y Y; Medina-Díaz, I M; Barrón-Vivanco, B S; Robledo-Marenco, M L; Salazar, A M; Rojas-García, A E

2015-06-01

Temephos is an organophosphorus pesticide that is used in control campaigns against Aedes aegypti mosquitoes, which transmit dengue. In spite of the widespread use of temephos, few studies have examined its genotoxic potential. The aim of this study was to evaluate the cytotoxic, cytostatic and genotoxic effects of temephos in human lymphocytes and hepatoma cells (HepG2). The cytotoxicity was evaluated with simultaneous staining (FDA/EtBr). The cytostatic and genotoxic effects were evaluated using comet assays and the micronucleus technique. We found that temephos was not cytotoxic in either lymphocytes or HepG2 cells. Regarding the cytostatic effect in human lymphocytes, temephos (10 μM) caused a significant decrease in the percentage of binucleated cells and in the nuclear division index as well as an increase in the apoptotic cell frequency, which was not the case for HepG2 cells. The comet assay showed that temephos increased the DNA damage levels in human lymphocytes, but it did not increase the MN frequency. In contrast, in HepG2 cells, temephos increased the tail length, tail moment and MN frequency in HepG2 cells compared to control cells. In conclusion, temephos causes stable DNA damage in HepG2 cells but not in human lymphocytes. These findings suggest the importance of temephos biotransformation in its genotoxic effect. Copyright © 2015. Published by Elsevier Ltd.

Chlorination of oxybenzone: Kinetics, transformation, disinfection byproducts formation, and genotoxicity changes.

PubMed

Zhang, Shujuan; Wang, Xiaomao; Yang, Hongwei; Xie, Yuefeng F

2016-07-01

UV filters are a kind of emerging contaminant, and their transformation behavior in water treatment processes has aroused great concern. In particular, toxic products might be produced during reaction with disinfectants during the disinfection process. As one of the most widely used UV filters, oxybenzone has received significant attention, because its transformation and toxicity changes during chlorine oxidation are a concern. In our study, the reaction between oxybenzone and chlorine followed pseudo-first-order and second-order kinetics. Three transformation products were detected by LC-MS/MS, and the stability of products followed the order of tri-chloro-methoxyphenoyl > di-chlorinated oxybenzone > mono-chlorinated oxybenzone. Disinfection byproducts (DBPs) including chloroform, trichloroacetic acid, dichloroacetic acid and chloral hydrate were quickly formed, and increased at a slower rate until their concentrations remained constant. The maximum DBP/oxybenzone molar yields for the four compounds were 12.02%, 6.28%, 0.90% and 0.23%, respectively. SOS/umu genotoxicity test indicated that genotoxicity was highly elevated after chlorination, and genotoxicity showed a significantly positive correlation with the response of tri-chloro-methoxyphenoyl. Our results indicated that more genotoxic transformation products were produced in spite of the elimination of oxybenzone, posing potential threats to drinking water safety. This study shed light on the formation of DBPs and toxicity changes during the chlorination process of oxybenzone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of Genotoxic Pressure along the Sava River

PubMed Central

Kračun-Kolarević, Margareta; Kostić, Jovana; Simonović, Predrag; Simić, Vladica; Milošković, Aleksandra; Reischer, Georg; Farnleitner, Andreas; Gačić, Zoran; Milačič, Radmila; Zuliani, Tea; Vidmar, Janja; Pergal, Marija; Piria, Marina; Paunović, Momir; Vuković-Gačić, Branka

2016-01-01

In this study we have performed a comprehensive genotoxicological survey along the 900 rkm of the Sava River. In total, 12 sites were chosen in compliance with the goals of GLOBAQUA project dealing with the effects of multiple stressors on biodiversity and functioning of aquatic ecosystems. The genotoxic potential was assessed using a complex battery of bioassays performed in prokaryotes and aquatic eukaryotes (freshwater fish). Battery comprised evaluation of mutagenicity by SOS/umuC test in Salmonella typhimurium TA1535/pSK1002. The level of DNA damage as a biomarker of exposure (comet assay) and biomarker of effect (micronucleus assay) and the level of oxidative stress as well (Fpg—modified comet assay) was studied in blood cells of bleak and spirlin (Alburnus alburnus/Alburnoides bipunctatus respectively). Result indicated differential sensitivity of applied bioassays in detection of genotoxic pressure. The standard and Fpg—modified comet assay showed higher potential in differentiation of the sites based on genotoxic potential in comparison with micronucleus assay and SOS/umuC test. Our data represent snapshot of the current status of the river which indicates the presence of genotoxic potential along the river which can be traced to the deterioration of quality of the Sava River by communal and industrial wastewaters. The major highlight of the study is that we have provided complex set of data obtained from a single source (homogeneity of analyses for all samples). PMID:27631093

Comet assay with gill cells of Mytilus galloprovincialis end point tools for biomonitoring of water antibiotic contamination: Biological treatment is a reliable process for detoxification.

PubMed

Mustapha, Nadia; Zouiten, Amina; Dridi, Dorra; Tahrani, Leyla; Zouiten, Dorra; Mosrati, Ridha; Cherif, Ameur; Chekir-Ghedira, Leila; Mansour, Hedi Ben

2016-04-01

This article investigates the ability of Pseudomonas peli to treat industrial pharmaceuticals wastewater (PW). Liquid chromatography-mass spectrometry (MS)/MS analysis revealed the presence, in this PW, of a variety of antibiotics such as sulfathiazole, sulfamoxole, norfloxacine, cloxacilline, doxycycline, and cefquinome.P. peli was very effective to be grown in PW and inducts a remarkable increase in chemical oxygen demand and biochemical oxygen demand (140.31 and 148.51%, respectively). On the other hand, genotoxicity of the studied effluent, before and after 24 h of shaking incubation with P. peli, was evaluated in vivo in the Mediterranean wild mussels Mytilus galloprovincialis using comet assay for quantification of DNA fragmentation. Results show that PW exhibited a statistically significant (p< 0.001) genotoxic effect in a dose-dependent manner; indeed, the percentage of genotoxicity was 122.6 and 49.5% after exposure to 0.66 ml/kg body weight (b.w.); 0.33 ml/kg b.w. of PW, respectively. However, genotoxicity decreased strongly when tested with the PW obtained after incubation with P. peli We can conclude that using comet assay genotoxicity end points are useful tools to biomonitor the physicochemical and biological quality of water. Also, it could be concluded that P. peli can treat and detoxify the studied PW. © The Author(s) 2013.

Genotoxicity assessment of membrane concentrates of landfill leachate treated with Fenton reagent and UV-Fenton reagent using human hepatoma cell line.

PubMed

Wang, Guifang; Lu, Gang; Yin, Pinghe; Zhao, Ling; Yu, Qiming Jimmy

2016-04-15

Membrane concentrates of landfill leachates contain organic and inorganic contaminants that could be highly toxic and carcinogenic. In this paper, the genotoxicity of membrane concentrates before and after Fenton and UV-Fenton reagent was assessed. The cytotoxicity and genotoxicity was determined by using the methods of methyltetrazolium (MTT), cytokinesis-block micronucleus (CBMN) and comet assay in human hepatoma cells. MTT assay showed a cytotoxicity of 75% after 24h of exposure to the highest tested concentration of untreated concentrates, and no cytotoxocity for UV-Fenton and Fenton treated concentrates. Both CBMN and comet assays showed increased levels of genotoxicity in cells exposed to untreated concentrates, compared to those occurred in cells exposed to UV-Fenton and Fenton reagent treated concentrates. There was no significant difference between negative control and UV-Fenton treated concentrates for micronucleus and comet assay parameters. UV-Fenton and Fenton treatment, especially the former, were effective methods for degradation of bisphenol A and nonylphenol in concentrates. These findings showed UV-Fenton and Fenton reaction were effective methods for treatment of such complex concentrates, UV-Fenton reagent provided toxicological safety of the treated effluent, and the genotoxicity assays were found to be feasible tools for assessment of toxicity risks of complex concentrates. Copyright © 2016 Elsevier B.V. All rights reserved.

β-Glucuronidase and β-glucosidase activity and human fecal water genotoxicity in the presence of probiotic lactobacilli and the heterocyclic aromatic amine IQ in vitro.

PubMed

Nowak, Adriana; Śliżewska, Katarzyna

2014-01-01

The aim of the study was to assess the genotoxicity of fecal water (FW) and the activity of fecal enzymes (β-glucuronidase and β-glucosidase) after incubation with 2-amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) and probiotic lactobacilli: Lb. casei 0900, Lb. casei 0908, and Lb. paracasei 0919. Our results show that the carcinogen IQ greatly increased FW genotoxicity (up to 16.92 ± 3.03 U/mg) and the activity of fecal enzymes (up to even 1.4 ± 0.16 U/mg) in 15 individuals (children, adults and elderly). After incubation with IQ, the activity of β-glucuronidase was reduced by Lactobacillus bacteria by 76.0% (Lb. paracasei 0908) in the FW of children, and by 82.0% (Lb. paracasei 0919) in the elderly; while that of β-glucosidase was reduced by 55.0% in children (Lb. casei 0908) and 90.0% (Lb. paracasei 0919) in elderly subjects. Lactobacilli decreased the genotoxicity of FW after incubation with IQ to the greatest extent in adults (by 64.5%). Probiotic lactobacilli, in the presence of IQ, efficiently inhibits activity of fecal enzymes to the level of control. Genotoxicity inhibition depends on the person's age, its individual microbiota and diet. Copyright © 2013 Elsevier B.V. All rights reserved.

Way forward in case of a false positive in vitro genotoxicity result for a cosmetic substance?

PubMed

Doktorova, Tatyana Y; Ates, Gamze; Vinken, Mathieu; Vanhaecke, Tamara; Rogiers, Vera

2014-02-01

The currently used regulatory in vitro mutagenicity/genotoxicity test battery has a high sensitivity for detecting genotoxicants, but it suffers from a large number of irrelevant positive results (i.e. low specificity) thereby imposing the need for additional follow-up by in vitro and/or in vivo genotoxicity tests. This could have a major impact on the cosmetic industry in Europe, seen the imposed animal testing and marketing bans on cosmetics and their ingredients. Afflicted, but safe substances could therefore be lost. Using the example of triclosan, a cosmetic preservative, we describe here the potential applicability of a human toxicogenomics-based in vitro assay as a potential mechanistically based follow-up test for positive in vitro genotoxicity results. Triclosan shows a positive in vitro chromosomal aberration test, but is negative during in vivo follow-up tests. Toxicogenomics analysis unequivocally shows that triclosan is identified as a compound acting through non-DNA reactive mechanisms. This proof-of-principle study illustrates the potential of genome-wide transcriptomics data in combination with in vitro experimentation as a possible weight-of-evidence follow-up approach for de-risking a positive outcome in a standard mutagenicity/genotoxicity battery. As such a substantial number of cosmetic compounds wrongly identified as genotoxicants could be saved for the future. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cytotoxic and genotoxic studies of essential oil from Rosa damascene Mill., Kashan, Iran.

PubMed

Shokrzadeh, Mohammad; Habibi, Emran; Modanloo, Mona

2017-08-01

Aim Rosa damascene Mill. belongs to the family of Roseaceae and its essential oil is produced in large amounts in Iran. The wide application of rose oil has raised questions about potential adverse health effects. We have investigated cytotoxic activity and genotoxic effects of Rosa oil from Kashan, Iran. Methods The cytotoxic effect and IC50 of the essential oil on the cell lines was studied followed by MTT assay. In this assay mitochondrial oxidoreductase enzymes with reducing the tetrazolium dye MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) reflect the number of viable cells. Genotoxic effect of the oil was evaluated by micronucleus assay by evaluating produced micronuclei due to cytogenetic damage in binucleated lymphocytes. Results The results showed that essential oil significantly had cytotoxic and genotoxic effects at doses over 10µg/mL (p<0.05). Also, essential oil of Rose showed lower IC50 in cancer cell line (A549) in comparison with the normal cell line (NIH3T3). Conclusion Cytotoxic and genotoxic properties of essential oil of Rose in Kashan, Iran, are safe at a dose of 10µg/mL. Also, a good cytotoxic effect was shown and could be introduced as an anticancer compound. Further studies are needed with regard to anti-cancer effects of Rose essential oil. Copyright© by the Medical Assotiation of Zenica-Doboj Canton.

Metabolically Competent Human Skin Models: Activation and Genotoxicity of Benzo[a]pyrene

PubMed Central

Henkler, Frank

2013-01-01

The polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (BP) is metabolized into a complex pattern of BP derivatives, among which the ultimate carcinogen (+)-anti-BP-7,8-diol-9,10-epoxide (BPDE) is formed to certain extents. Skin is frequently in contact with PAHs and data on the metabolic capacity of skin tissue toward these compounds are inconclusive. We compared BP metabolism in excised human skin, commercially available in vitro 3D skin models and primary 2D skin cell cultures, and analyzed the metabolically catalyzed occurrence of seven different BP follow-up products by means of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). All models investigated were competent to metabolize BP, and the metabolic profiles generated by ex vivo human skin and skin models were remarkably similar. Furthermore, the genotoxicity of BP and its derivatives was monitored in these models via comet assays. In a full-thickness skin, equivalent BP-mediated genotoxic stress was generated via keratinocytes. Cultured primary keratinocytes revealed a level of genotoxicity comparable with that of direct exposure to 50–100nM of BPDE. Our data demonstrate that the metabolic capacity of human skin ex vivo, as well as organotypic human 3D skin models toward BP, is sufficient to cause significant genotoxic stress and thus cutaneous bioactivation may potentially contribute to mutations that ultimately lead to skin cancer. PMID:23148024

Genistein genotoxicity: Critical considerations of in vitro exposure dose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, Catherine B.; King, Audrey A.

The potential health benefits of soy-derived phytoestrogens include their reported utility as anticarcinogens, cardioprotectants and as hormone replacement alternatives in menopause. Although there is increasing popularity of dietary phytoestrogen supplementation and of vegetarian and vegan diets among adolescents and adults, concerns about potential detrimental or other genotoxic effects persist. While a variety of genotoxic effects of phytoestrogens have been reported in vitro, the concentrations at which such effects occurred were often much higher than the physiologically relevant doses achievable by dietary or pharmacologic intake of soy foods or supplements. This review focuses on in vitro studies of the most abundantmore » soy phytoestrogen, genistein, critically examining dose as a crucial determinant of cellular effects. In consideration of levels of dietary genistein uptake and bioavailability we have defined in vitro concentrations of genistein > 5 {mu}M as non-physiological, and thus 'high' doses, in contrast to much of the previous literature. In doing so, many of the often-cited genotoxic effects of genistein, including apoptosis, cell growth inhibition, topoisomerase inhibition and others become less obvious. Recent cellular, epigenetic and microarray studies are beginning to decipher genistein effects that occur at dietarily relevant low concentrations. In toxicology, the well accepted principle of 'the dose defines the poison' applies to many toxicants and can be invoked, as herein, to distinguish genotoxic versus potentially beneficial in vitro effects of natural dietary products such as genistein.« less

Improved in silico prediction of carcinogenic potency (TD50) and the risk specific dose (RSD) adjusted Threshold of Toxicological Concern (TTC) for genotoxic chemicals and pharmaceutical impurities.

PubMed

Contrera, Joseph F

2011-02-01

The Threshold of Toxicological Concern (TTC) is a level of exposure to a genotoxic impurity that is considered to represent a negligible risk to humans. The TTC was derived from the results of rodent carcinogenicity TD50 values that are a measure of carcinogenic potency. The TTC currently sets a default limit of 1.5 μg/day in food contact substances and pharmaceuticals for all genotoxic impurities without carcinogenicity data. Bercu et al. (2010) used the QSAR predicted TD50 to calculate a risk specific dose (RSD) which is a carcinogenic potency adjusted TTC for genotoxic impurities. This promising approach is currently limited by the software used, a combination of MC4PC (www.multicase.com) and a Lilly Inc. in-house software (VISDOM) that is not available to the public. In this report the TD50 and RSD were predicted using a commercially available software, SciQSAR (formally MDL-QSAR, www.scimatics.com) employing the same TD50 training data set and external validation test set that was used by Bercu et al. (2010). The results demonstrate the general applicability of QSAR predicted TD50 values to determine the RSDs for genotoxic impurities and the improved performance of SciQSAR for predicting TD50 values. Copyright © 2010 Elsevier Inc. All rights reserved.

Strategies for setting occupational exposure limits for particles.

PubMed Central

Greim, H A; Ziegler-Skylakakis, K

1997-01-01

To set occupational exposure limits (OELs) for aerosol particles, dusts, or chemicals, one has to evaluate whether mechanistic considerations permit identification of a no observed effect level (NOEL). In the case of carcinogenic effects, this can be assumed if no genotoxicity is involved, and exposure is considered safe if it does not exceed the NOEL. If tumor induction is associated with genotoxicity, any exposure is considered to be of risk, although a NOEL may be identified in the animal or human exposure studies. This must also be assumed when no information on the carcinogenic mechanism, including genotoxicity, is available. Aerosol particles, especially fibrous dusts, which include man-made mineral fiber(s) (MMMF), present a challenge for toxicological evaluation. Many MMMF that have been investigated have induced tumors in animals and genotoxicity in vitro. Since these effects have been associated with long-thin fiber geometry and high durability in vivo, all fibers meeting such criteria are considered carcinogenic unless the opposite has been demonstrated. This approach is practicable. Investigations on fiber tumorigenicity/genotoxicity should include information on dose response, pathobiochemistry, particle clearance, and persistence of the material in the target organ. Such information will introduce quantitative aspects into the qualitative approach that has so far been used to classify fibrous dusts as carcinogens. The rationales for classifying the potential carcinogenicity of MMMF and for setting OELs used by the different European committees and regulatory agencies are described. PMID:9400750

Lack of genotoxicity in Astyanax bimaculatus and Oreochromis niloticus of 17α-methyltestosterone used in fish hatcheries to produce male monosex populations.

PubMed

Rivero-Wendt, C L G; Miranda-Vilela, A L; Ferreira, M F N; Amorim, F S; da Silva, V A G; Louvandini, H; Grisolia, C K

2013-10-24

17α-Methyltestosterone (MT) is widely used in fish hatcheries of many countries to produce male monosex populations. Its genotoxic risk to fish species is not well known and studies in other in vivo models are still inconclusive. MT was tested for genotoxicity in the fish species Oreochromis niloticus (tilapia), a target species, and Astyanax bimaculatus (lambari), a native non-target species. Genotoxicity was evaluated by the micronucleus test (MN), nuclear abnormalities (NA), and comet assay using peripheral erythrocytes of both species after a 96-h exposure to MT at concentrations of 0.01, 0.1, and 1.0 mg/L in the water. At the lowest exposure level of 0.01 mg/L, MT induced MN in both species and NA only in O. niloticus. These effects were not observed in the comet assay. Chromatographic analysis of water samples collected from aquariums at the beginning and end of each experiment showed that MT was consumed during the 96-h exposure. At the highest level of exposure (1.0 mg/L), 81.69% of the hormone was consumed during the exposure period. The chromatogram showed that at the lowest concentration level of 0.01 mg/L, 99.56% MT was consumed by the end of the exposure period. Thus, exposure to MT did not cause genotoxicity in either fish species.

Genotoxicity of quinocetone, cyadox and olaquindox in vitro and in vivo.

PubMed

Ihsan, Awais; Wang, Xu; Zhang, Wei; Tu, Honggang; Wang, Yulian; Huang, Lingli; Iqbal, Zahid; Cheng, Guyue; Pan, Yuanhu; Liu, Zhenli; Tan, Ziqiang; Zhang, Yuanyuan; Yuan, Zonghui

2013-09-01

Quinocetone (QCT) and Cyadox (CYA) are important derivative of heterocyclic N-oxide quinoxaline (QdNO), used actively as antimicrobial feed additives in China. Here, we tested and compared the genotoxic potential of QCT and CYA with olaquindox (OLA) in Ames test, HGPRT gene mutation (HGM) test in V79 cells, unscheduled DNA synthesis (UDS) assay in human peripheral lymphocytes, chromosome aberration (CA) test, and micronucleus (MN) test in mice bone marrow. OLA was found genotoxic in all 5 assays. In Ames test, QCT produced His(+) mutants at 6.9 μg/plate in Salmonella typhimurium TA 97, at 18.2 μg/plate in TA 100, TA 1535, TA 1537, and at 50 μg/plate in TA 98. CYA produced His(+) mutants at 18.2 μg/plate in TA 97, TA 1535, and at 50 μg/plate in TA 98, TA 100 and TA 1537. QCT was found positive in HGM and UDS assay at concentrations ≥10 μg/ml while negative results were reported in CA test and MN test. Collectively, we found that OLA was more genotoxic than QCT and CYA. Genotoxicity of QCT was found at higher concentration levels in Ames test, HGM and UDS assays while CYA showed weak mutagenic potential to bacterial cells in Ames test. Copyright © 2013 Elsevier Ltd. All rights reserved.

Contaminant bioavailability in soil and phytotoxicity/genotoxicity tests in Vicia faba L.: a case study of boron contamination.

PubMed

Barbafieri, Meri; Giorgetti, Lucia

2016-12-01

In this work, the model plant for genotoxicity studies Vicia faba L. was used to investigate the relation between Boron (B) content and bioavailability in soil and plant genotoxic/phytotoxic response. A total of nine soil samples were investigated: two soil samples were collected from a B-polluted industrial area in Cecina (Tuscany, Italy), the other samples were obtained by spiking control soil (from a not polluted area of the basin) with seven increased doses of B, from about 20 to 100 mg B kg -1 . As expected, B availability, evaluated by chemical extraction, was higher (twofold) in spiked soils when compared with collected polluted soils with the same B total content. To analyze the phytotoxic effects of B, seed germination, root elongation, biomass production, and B accumulation in plant tissues were considered in V. faba plants grown in the various soils. Moreover, the cytotoxic/genotoxic effects of B were investigated in root meristems by mitotic index (MI) and micronuclei frequency (MCN) analysis. The results highlighted that V. faba was a B-sensitive plant and the appearance of phytotoxic effects, which altered plant growth parameters, were linearly correlated to the bioavailable B concentration in soils. Concerning the occurrence of cytotoxic/genotoxic effects induced by B, no linear correlation was observed even if MCN frequency was logarithmic correlated with the concentration of B bioavailable in soils.

Ribosomal Alterations Controlling Alkaline Phosphatase Isozymes in Escherichia coli

PubMed Central

Piggot, P. J.; Sklar, M. D.; Gorini, L.

1972-01-01

Different patterns of isozymes were obtained by starch-gel electrophoresis of alkaline phosphatase from Escherichia coli strains differing only by strA or ram mutations, or both, in the 30S ribosomal subunit. The isozyme spread was reduced in strA and increased in ram strains; this strictly parallels the restriction and enhancement of translational ambiguity produced by these mutations. Streptomycin present during growth had an effect similar to ram on both isozymes and ambiguity. The three isozymes analyzed have different N-terminal residues: aspartic acid, valine, and threonine. Different patterns of isozymes were also obtained in a wild-type strain through the specific action of exogenous arginine. A link between the mechanism of the effect of arginine and that of the ribosome is not obvious. The possibility is discussed that in both cases, although by different mechanisms, N-terminals are formed with different sensitivity to limited degradative attack. Images PMID:4552993

Fungal biodegradation and biotransformation of soluble lignocarbohydrate complexes from straw. [Aspergillus japonicus, Polyporus versicolor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milstein, O.A.; Vared, Y.; Sharma, A.

1983-08-01

Aspergillus japonicus is an efficient degrader of phenolics and carbohydrates present in a mixture of soluble lignocarbohydrate complexes extracted from wheat straw. Trichoderma species attacked part of the carbohydrate but hardly affected the aromatic portion of this solution. Polyporus versicolor had a complex effect; polymerization of low-molecular-size phenolics accompanied the degradation of aromatic and carbohydrate polymers. The addition of xylose to the medium facilitated depolymerization of lignin by the fungi tested and prevented the polymerization of low-molecular-size fractions of lignocarbohydrate complexes by P. versicolor. P. versicolor, in contrast to A. japonicus and Trichoderma species, also excreted into the medium considerablemore » amounts of laccase, but only in the absence of endogenous or exogenous carbohydrates. Apparently, laccase is involved in polymerization rather than degradation of lignin in this organism. A number of extracellular glycanases were also secreted by these fungi. 19 references« less

INSTABILITY OF THE WATER DISINFECTION BY-PRODUCT DIBROMOACETONITRILE UNDER PHYSIOLOGICAL CONDITIONS: KINETICS AND PRODUCT CHARACTERIZATION

EPA Science Inventory

Dibromoacetonitrile (DBAN) is a prevalent haloacetonitrile formed as a byproduct of water chlorination. DBAN is toxic in vivo and genotoxic in vitro and is a mouse skin tumor initiator. However, little is known about its mechanisms of toxicity or genotoxicity or its stability. Du...

EFFECTS OF HEAT SHOCK PROTEIN 70 (HSP70) ON ARSENITE INDUCED GENOTOXICITY

EPA Science Inventory

Arsenic (As), a human carcinogen, is known to be genotoxic although its mechanism(s) of action for tumorigenesis is not well understood. Among the toxicity-related properties of this chemical are its clastogenic and aneugenic activities, as well as its capacity for inducing stres...

Method for protection against genotoxic mutagenesis

DOEpatents

Grdina, D.J.

1996-01-30

A method and pharmaceutical for protecting against genotoxic damage in irradiated cells are disclosed. Reduction of mutations at the hypoxanthine-guanine phosphoribosyl transferase locus is accomplished by administering an effective dose of a compound having protected sulfhydryl groups which metabolize in vivo to produce both free sulfhydryl groups and disulfides. 10 figs.

Development of a Quantitative Model Incorporating Key Events in a Hepatoxic Mode of Action to Predict Tumor Incidence

EPA Science Inventory

Biologically-Based Dose Response (BBDR) modeling of environmental pollutants can be utilized to inform the mode of action (MOA) by which compounds elicit adverse health effects. Chemicals that produce tumors are typically described as either genotoxic or non-genotoxic. One common...

GENOTOXICITY OF BIOREMEDIATED SOILS FROM THE REILLY TARSITE, ST. LOUIS PARK, MINNESOTA

EPA Science Inventory

An in vitro approach was used to measure the genotoxicity of creosote-contaminated soil before and after four bioremediation processes. The soil was taken from the Reilly Tar site, a closed Superfund site in Saint Louis Park, Minnesota. The creosote soil was bioremediated in bios...

Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water

EPA Science Inventory

Among the 11 disinfection by-products (DBPs) in drinking water that are regulated by the U.S. EPA, (a) 2 DBPs (chloroaceticacid and chlorite) are not carcinogenic-in either of2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxicity...

Genotoxicity of Swimming Pool Water and Carcinogenicity of Drinking Water**

EPA Science Inventory

Among the 11 disinfection by-products (DBPs) in drinking water that are regulated by the U.S. EPA, (a) 2 DBPs (chloroaceticacid and chlorite) are not carcinogenic-in either of2 species; (b) chlorite is not carcinogenic in 3 rodent assays and has never been tested for genotoxicity...

Emerging Issues in Genotoxicity and Carcinogenicity with Implications for Structure Activity Analyses

EPA Science Inventory

In silico systems for the prediction of the ability of chemicals to induce carcinogenicity in rodents have generally relied on knowledge of the structure and physical-chemical features of the compound, as well as the mutagenic and genotoxic features of the compound in various bio...

METHYLATED ARSENICIII SPECIES ARE POTENTIAL PROXIMATE OR ULTIMATE GENOTOXIC FORMS OF ARSENIC

EPA Science Inventory

METHYLATED ARSENIC(III) SPECIES ARE POTENTIAL PROXIMATE OR UL TIMA TE GENOTOXIC FORMS OF ARSENIC

Inorganic arsenic (iAs, arsenite and arsenate) has been thought to act as a genotoxicant without reacting directly with DNA; neither iAs nor As(V) methylated metabolites are e...

High-throughput genotoxicity assay identifies antioxidants as inducers of DNA damage response and cell death

EPA Science Inventory

Human ATAD5 is an excellent biomarker for identifying genotoxic compounds because ATADS protein levels increase post-transcriptionally following exposure to a variety of DNA damaging agents. Here we report a novel quantitative high-throughput ATAD5-Iuciferase assay that can moni...

True Lies: The Double Life of the Nucleotide Excision Repair Factors in Transcription and DNA Repair

PubMed Central

Le May, Nicolas; Egly, Jean-Marc; Coin, Frédéric

2010-01-01

Nucleotide excision repair (NER) is a major DNA repair pathway in eukaryotic cells. NER removes structurally diverse lesions such as pyrimidine dimers, arising upon UV irradiation or bulky chemical adducts, arising upon exposure to carcinogens and some chemotherapeutic drugs. NER defects lead to three genetic disorders that result in predisposition to cancers, accelerated aging, neurological and developmental defects. During NER, more than 30 polypeptides cooperate to recognize, incise, and excise a damaged oligonucleotide from the genomic DNA. Recent papers reveal an additional and unexpected role for the NER factors. In the absence of a genotoxic attack, the promoters of RNA polymerases I- and II-dependent genes recruit XPA, XPC, XPG, and XPF to initiate gene expression. A model that includes the growth arrest and DNA damage 45α protein (Gadd45α) and the NER factors, in order to maintain the promoter of active genes under a hypomethylated state, has been proposed but remains controversial. This paper focuses on the double life of the NER factors in DNA repair and transcription and describes the possible roles of these factors in the RNA synthesis process. PMID:20725631

Genotoxicity of the Musi River (Hyderabad, India) investigated with the VITOTOX test.

PubMed

Vijayashree, B; Ahuja, Y R; Regniers, L; Rao, V; Verschaeve, L

2005-01-01

The bacterial VITOTOX genotoxicity test was used to screen water samples collected from three different stations along the banks of the river Musi, in Hyderabad, India. Water was collected at three stations that differed from each other in the nature of the surrounding industrial and other activities. A number of different pollutants were also measured in water, soil and air samples. The three stations were found highly polluted and different with regard to the genotoxicity and toxicity of their samples. These results demonstrate the need for further biological studies in this area to generate valuable data on genomic instability, risk assessment of cancer, and to provide avenues for risk management.

Studies on the genotoxic properties of essential oils with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay.

PubMed

Zani, F; Massimo, G; Benvenuti, S; Bianchi, A; Albasini, A; Melegari, M; Vampa, G; Bellotti, A; Mazza, P

1991-06-01

Genotoxic properties of essential oils from Anthemis nobilis L., Artemisia dracunculus L., Salvia officinalis L., Salvia sclarea L., Satureja hortensis L., Satureja montana L., Thymus capitatus L., Thymus citriodorus Schreb., Thymus vulgaris L., Citrus bergamia Risso, were studied with Bacillus subtilis rec-assay and Salmonella/microsome reversion assay. The essential oil of Artemisia dracunculus L. "Piemontese" turned out to be active in the rec-assay but not in the Salmonella test. DNA-damaging activity was demonstrated to be due to the estragol component of the oil. Advantages of the combined use of these two short-term microbial assays in genotoxic studies are discussed.

Summary of major conclusions from the 6th International Workshop on Genotoxicity Testing (IWGT), Foz do Iguacu, Brazil

EPA Science Inventory

The paper describes major conclusions of working groups convened in the following areas: comet assay; micronucleus test in the liver and organs other than bone marrow; pig-A assay; quantitative approaches to genotoxicity risk assessment; and approaches for identifying germ cell m...

GENOTOXIC ACTIVITY OF 1-CHLOROMETHYLPYRENE IN STOMACH EPITHELIUM IN VIVO: INSENSITIVITY OF THE SCINTILLATION UDS ASSAY

EPA Science Inventory

An acknowledged weakness of current testing programs for genotoxic hazard has been the potential insensitivity of the established mouse bone ma,-row micronucleus test and rat liver UDS assays to direct-acting or short lived mutagens which may be consumed at the site of initial co...

A MASS BALANCE OF SURFACE WATER GENOTOXICITY IN PROVIDENCE RIVER (RHODE ISLAND USA)

EPA Science Inventory

White and Rasmussen (Mutation Res. 410:223-236) used a mass balance approach to demonstrate that over 85% of the total genotoxic loading to the St. Lawrence River at Montreal is non-industrial. To validate the mass balance approach and investigate the sources of genotoxins in sur...

ASSESSING HUMAN EXPOSURE AND GENOTOXIC EFFECTS IN HUMAN EXFOLIATED EPITHELIA FROM INDIVDUALS IVING IN AN ENDEMIC REGION IN INNER MONGOLAI

EPA Science Inventory

A pilot study was conducted to characterize arsenic exposure and genotoxic effects in Ba Men located in West Central Inner Mongolia in an attempt to identify biomarkers useful for assessing health risk resulting from chronic arsenic exposure. The study subjects included 19 high ...

REDUCTION OF GENOTOXICITY OF A CREOSOTE-CONTAMINATED SOIL AFTER FUNGAL TREATMENT DETERMINED BY THE TRADESCANTIA-MICRONUCLEUS TEST

EPA Science Inventory

The fungal degradation of polyaromatic hydrocarbons (PAH) in a contaminated soil from a hazarous waste site was evaluated in a pilot-scale study. As some PAH are known to be mutagens, the Tradescantia-micronucleus test (TRAD-MCN) was selected to evaluate the genotoxicity of the s...

Biomarkers of Exposure and Effect in Migrant Farmworker Children of Mexican Origin from Urban and Agricultural Regions of Texas

EPA Science Inventory

Some organophosphate pesticides (OPs) induce chromosome aberrations (CA) in experimental systems and may be genotoxic in persons exposed to home-use levels of OPs. However, the genotoxic effects of OPs have not been studied extensively in environmentally exposed children, such a...

GENOTOXICITY STUDIES OF THREE TRIAZINE HERBICIDES III. IN VIVO STUDIES USING THE ALKALINE SINGLE CELL GEL (SCG) ASSAY

EPA Science Inventory

Abstract

Triazine herbicides are prevalent contaminants of groundwater in the agricultural regions of the United States. The literature on the genotoxicity of triazines is rife with conflicting data, though the general tendency is for most studies to report negative resul...

Evaluation of High-throughput Genotoxicity Assays Used in Profiling the US EPA ToxCast Chemicals

EPA Science Inventory

Three high-throughput screening (HTS) genotoxicity assays-GreenScreen HC GADD45a-GFP (Gentronix Ltd.), CellCiphr p53 (Cellumen Inc.) and CellSensor p53RE-bla (Invitrogen Corp.)-were used to analyze the collection of 320 predominantly pesticide active compounds being tested in Pha...

MODULATION OF THE CYTOTOXICITY AND GENOTOXICITY OF THE DRINKING WATER DBP IODOACETIC ACID BY SUPPRESSORS OF OXIDATIVE STRESS

EPA Science Inventory

Drinking water disinfection by-products (DBPs) are generated by the chemical disinfection of water and may pose a hazard to the public health. Previously we demonstrated that iodoacetic acid was the most cytotoxic and genotoxic DBP analyzed in a mammalian cell system. Little is k...

Genotoxicity of endosseous implants using two cellular lineages in vitro.

PubMed

Matsumoto, Mariza; Filho, Hugo Nary; Ferrari, Raquel; Fernandes, Kristianne; Renno, Ana Claudia; Ribeiro, Daniel

2014-02-01

The genotoxic potential of corrosion eluates obtained from a single dental implant using murine fibroblasts or osteoblasts cells in vitro by the single-cell gel (comet) assay was examined. A single commercially available dental implant (Biotechnology) was eluted in a solution consisting of equal amounts of acetic acid and sodium chloride (0.1 M) for 1, 3, 7, 14, and 21 days. Murine fibroblast or osteoblast cultures were then exposed to all corrosion eluates obtained from endosseous dental implants for 30 minutes at 37°C. The results suggest that none of the eluates produced genotoxic changes in murine fibroblasts regardless of the length of exposure to the eluate. Similarly, no genotoxicity was found in osteoblasts. The results suggest that the dental implant eluates tested in this study did not induce genetic damage as depicted by the single-cell gel (comet) assay. Because DNA damage is an important event during oncogenesis, this study represents a relevant contribution to estimate the real risks to the cellular system induced by the corrosion products of a dental implant.

Genotoxicity and Cytotoxicity Evaluation of the Neolignan Analogue 2-(4-Nitrophenoxy)-1Phenylethanone and its Protective Effect Against DNA Damage

PubMed Central

Hanusch, Alex Lucas; de Oliveira, Guilherme Roberto; de Sabóia-Morais, Simone Maria Teixeira; Machado, Rafael Cosme; dos Anjos, Murilo Machado; Chen Chen, Lee

2015-01-01

Neolignans are secondary metabolites found in various groups of Angiosperms. They belong to a class of natural compounds with great diversity of chemical structures and pharmacological activities. These compounds are formed by linking two phenylpropanoid units. Several compounds that have ability to prevent genetic damage have been isolated from plants, and can be used to prevent or delay the development of tumor cells. Genetic toxicology evaluation is widely used in risk assessment of new drugs in preclinical screening tests. In this study, we evaluated the genotoxicity and cytotoxicity of the neolignan analogue 2-(4-nitrophenoxy)-1-phenylethanone (4NF) and its protective effect against DNA damage using the mouse bone marrow micronucleus test and the comet assay in mouse peripheral blood. Our results showed that this neolignan analogue had no genotoxic activity and was able to reduce induced damage both in mouse bone marrow and peripheral blood. Although the neolignan analogue 4NF was cytotoxic, it reduced cyclophosphamide-induced cytotoxicity. In conclusion, it showed no genotoxic action, but exhibited cytotoxic, antigenotoxic, and anticytotoxic activities. PMID:26554835

Embryotoxicity and genotoxicity evaluation of sediments from Yangtze River estuary using zebrafish (Danio rerio) embryos.

PubMed

Li, Qian; Chen, Ling; Liu, Li; Wu, Lingling

2016-03-01

Sediments function both as a sink and a source of pollutants in aquatic ecosystems and may impose serious effects on benthic organisms and human health. As one of the largest estuaries in the world, the Yangtze River estuary suffers from abundant wastewater from the coastal cities. In this study, the zebrafish (Danio rerio) embryos were employed in the fish embryo test and a comet assay to evaluate the embryotoxicity and genotoxicity of the sediments from the Yangtze River estuary, respectively. Results showed that the sediments from the Yangtze River estuary significantly increased mortality, induced development abnormalities, and reduced hatching rate and heart rate of zebrafish embryos after 96 h of exposure. Significant genotoxicity was observed in the samples relative to the controls. Relatively low-level embryotoxicity and genotoxicity of sediments were found in the Yangtze River compared with other river systems. Toxic responses were also discussed in relation to the analyzed organic contaminants in sediments. More attention should be paid to non-priority pollutant monitoring in the Yangtze River estuary.

The application of the micronucleus test in Chinese hamster V79 cells to detect drug-induced photogenotoxicity.

PubMed

Kersten, B; Zhang, J; Brendler-Schwaab, S Y; Kasper, P; Müller, L

1999-09-15

Recent reports on the photochemical carcinogenicity and photochemical genotoxicity of fluoroquinolone antibacterials led to an increasing awareness for the need of a standard approach to test for photochemical genotoxicity. In this study the micronucleus test using V79 cells was adapted to photogenotoxicity testing. Results of using different UVA/UVB relationships enabled us to identify a suitable irradiation regimen for the activation of different kinds of photosensitizers. Using this regimen, 8-methoxypsoralen and the fluoroquinolones lomefloxacin, grepafloxacin and Bay Y 3118 were identified to cause micronuclei and toxicity upon photochemical activation. Among the phenothiazines tested, chlorpromazine and 2-chlorophenothiazine, were positive for both endpoints, whereas triflupromazine was only slightly photoclastogenic in the presence of strong phototoxicity. Among the other potential human photosensitizers tested (oxytetracycline, doxycycline, metronidazole, emodin, hypericin, griseofulvin), only hypericin was slightly photogenotoxic. Photochemical toxicity in the absence of photochemical genotoxicity was noted for doxycycline and emodin. With the assay system described, it is possible to determine photochemical toxicity and photochemical genotoxicity concomitantly with sufficient reliability.

In vitro assessment of the genotoxic and cytotoxic effects of boiled juice (tucupi) from Manihot esculenta Crantz roots.

PubMed

Cunha, L A; Mota, T C; Cardoso, P C S; Alcântara, D D F Á; Burbano, R M R; Guimarães, A C; Khayat, A S; Rocha, C A M; Bahia, M O

2016-10-05

The population of Pará (a state in Brazil) has a very characteristic food culture, as a majority of the carbohydrates consumed are obtained from cassava (Manihot esculenta Crantz) derivatives. Tucupi is the boiled juice of cassava roots that plays a major role in the culinary footprint of Pará. Before boiling, this juice is known as manipueira and contains linamarin, a toxic glycoside that can decompose to hydrogen cyanide. In this study, the cytotoxic and genotoxic effects of tucupi on cultured human lymphocytes were assessed using the comet assay and detection of apoptosis and necrosis by differential fluorescent staining with acridine orange-ethidium bromide. Tucupi concentrations (v/v) were determined using the methylthiazole tetrazolium biochemical test. Concentrations of tucupi that presented no genotoxic effects (2, 4, 8, and 16%) were used in our experiments. The results showed that under our study conditions, tucupi exerted no genotoxic effects; however, cytotoxic effects were observed with cell death mainly induced by necrosis. These effects may be related to the presence of hydrogen cyanide in the juice.

METABOLISM, GENOTOXICITY, AND CARCINOGENICITY OF COMFREY

PubMed Central

Mei, Nan; Guo, Lei; Fu, Peter P.; Fuscoe, James C.; Luan, Yang; Chen, Tao

2018-01-01

Comfrey has been consumed by humans as a vegetable and a tea and used as an herbal medicine for more than 2000 years. Comfrey, however, produces hepatotoxicity in livestock and humans and carcinogenicity in experimental animals. Comfrey contains as many as 14 pyrrolizidine alkaloids (PA), including 7-acetylintermedine, 7-acetyllycopsamine, echimidine, intermedine, lasiocarpine, lycopsamine, myoscorpine, symlandine, symphytine, and symviridine. The mechanisms underlying comfrey-induced genotoxicity and carcinogenicity are still not fully understood. The available evidence suggests that the active metabolites of PA in comfrey interact with DNA in liver endothelial cells and hepatocytes, resulting in DNA damage, mutation induction, and cancer development. Genotoxicities attributed to comfrey and riddelliine (a representative genotoxic PA and a proven rodent mutagen and carcinogen) are discussed in this review. Both of these compounds induced similar profiles of 6,7-dihydro-7-hydroxy-1-hydroxymethyl-5H-pyrrolizine (DHP)-derived DNA adducts and similar mutation spectra. Further, the two agents share common mechanisms of drug metabolism and carcinogenesis. Overall, comfrey is mutagenic in liver, and PA contained in comfrey appear to be responsible for comfrey-induced toxicity and tumor induction. PMID:21170807

[Cytotoxicity and genotoxicity of drinking water of two networks supplied by surface water].

PubMed

Pellacani, Claudia; Branchi, Elisa; Buschini, Annamaria; Furlini, Mariangela; Poli, Paola; Rossi, Carlo

2005-01-01

Evaluation of cytotoxic and genotoxic load of drinking water in relationship to the source of supplies, the disinfection process, and the piping system. Two treatment/distribution networks of drinking water, the first (#1) located near the source, the second (#2) located near the mouth of a river supplying the plants. Water samples were collected before (F) and after (A) the disinfection process and in two points (R1 and R2) of the piping system. The samples, concentrated on C18, were tested for DNA damage in human leukocytes by the Comet assay and for gene conversion, reversion and mitochondrial mutability in Saccharomyces cerevisiae D7 strain. The approach used in this study is able to identify genotoxic compounds at low concentration and evaluate their antagonism/synergism in complex mixtures. Comet assay results show that the raw water quality depends on the sampling point, suggesting that a high input of environmental pollutants occurred during river flowing; they also show that the disinfection process can both detoxify or enhance biological activity of raw water according to its quality and that the piping systems do not affect tap water cytotoxic/genotoxic load. The yeast tests indicate the presence of some disinfection by-products effective on mitochondrial DNA. The biological assays used in this study are proven to be able to detect the presence of low concentrations of toxic/genotoxic compounds and assess the sources of their origin/production.

Absence of toxicity and genotoxicity in an extract of Rubus coriifolius.

PubMed

González-Hernández, S; González-Ramírez, D; Dávila-Rodríguez, M I; Jimenez-Arellanez, A; Meckes-Fischer, M; Said-Fernández, S; Cortés-Gutiérrez, E I

2016-12-02

Rubus coriifolius Focke is a wild plant from the Rosaceae family. It grows in both Guatemala and Mexico. The polar extract of the aerial parts of this plant has antibacterial, anti-inflammatory, and anti-protozoal activities. These properties may explain the traditional use of this plant. In vivo and in vitro assays were used to assess the genotoxic and toxic effects of an ethanol extract of the aerial parts of R. coriifolius. Three groups of rats were orally administered the R. coriifolius extract diluted in ethanol (5%) at doses of 1.89 mg/kg body weight (low dose), 4.72 mg/kg body weight (medium dose), and 9.44 mg/kg body weight (high dose) for 3 weeks. Genotoxic/cytotoxic effects induced by the R. coriifolius ethanol extract were evaluated in vivo by a micronuclei (MN) test in rat's bone marrow cells and in vitro by MN and sister chromatid exchange (SCE) in human lymphocyte cultures. In vivo genotoxicity analyses revealed that the average number of micronucleated polychromatic erythrocytes and the polychromatic erythrocyte/red blood cell ratio at all doses were not significantly different from those of the negative control. In vitro genotoxicity analyses showed that MN, SCE, and proliferative index frequencies in a human lymphocyte cell culture were not significantly different from those of the negative control. These results demonstrate that the ethanol extract of R. coriifolius aerial parts is not toxic or mutagenic (in vitro and in vivo) and does not affect cell proliferation at the concentrations analyzed.

Two dechlorinated chlordecone derivatives formed by in situ chemical reduction are devoid of genotoxicity and mutagenicity and have lower proangiogenic properties compared to the parent compound.

PubMed

Legeay, Samuel; Billat, Pierre-André; Clere, Nicolas; Nesslany, Fabrice; Bristeau, Sébastien; Faure, Sébastien; Mouvet, Christophe

2018-05-01

Chlordecone (CLD) is a chlorinated hydrocarbon insecticide, now classified as a persistent organic pollutant. Several studies have previously reported that chronic exposure to CLD leads to hepatotoxicity, neurotoxicity, raises early child development and pregnancy complications, and increases the risk of liver and prostate cancer. In situ chemical reduction (ISCR) has been identified as a possible way for the remediation of soils contaminated by CLD. In the present study, the objectives were (i) to evaluate the genotoxicity and the mutagenicity of two CLD metabolites formed by ISCR, CLD-5a-hydro, or CLD-5-hydro (5a- or 5- according to CAS nomenclature; CLD-1Cl) and tri-hydroCLD (CLD-3Cl), and (ii) to explore the angiogenic properties of these molecules. Mutagenicity and genotoxicity were investigated using the Ames's technique on Salmonella typhimurium and the in vitro micronucleus micromethod with TK6 human lymphoblastoid cells. The proangiogenic properties were evaluated on the in vitro capillary network formation of human primary endothelial cells. Like CLD, the dechlorinated derivatives of CLD studied were devoid of genotoxic and mutagenic activity. In the assay targeting angiogenic properties, significantly lower microvessel lengths formed by endothelial cells were observed for the CLD-3Cl-treated cells compared to the CLD-treated cells for two of the three tested concentrations. These results suggest that dechlorinated CLD derivatives are devoid of mutagenicity and genotoxicity and have lower proangiogenic properties than CLD.

Genotoxic and Antigenotoxic Potential of Momordica charantia Linn (Cucurbitaceae) in the Wing Spot Test of Drosophila melanogaster.

PubMed

Guterres, Zaira Rosa; Zanetti, Thalita Alves; Sennes-Lopes, Tiago Felipe; da Silva, Ana Francisca Gomes

2015-10-01

Momordica charantia, popularly known as bitter melon, is a plant widely used in ethnobotanical medicine. It has antibacterial, antifungal, anthelmintic, antidiabetic, antiviral, and antimalarial activities, among others. The goal of this study was to evaluate the genotoxic and/or antigenotoxic activity of the aqueous extracts obtained from the aerial parts and fruit of this plant by means of the Drosophila melanogaster wing spot test. Third-stage larvae that obtained standard (ST) cross and high bioactivation (HB) cross were treated with aqueous extracts of the aerial parts (IQA) and fruit (IQF) of M. charantia, following two protocols (genotoxicity and antigenotoxicity). The aqueous extracts are not genotoxic in lower concentrations. The frequencies of mutant spots observed in the descendants of the ST and HB crosses treated with doxorubicin (DXR) alone were 8.65 and 9.25, respectively, whereas in those cotreated with IQA and DXR, the frequencies ranged from 15.90 to 29 in the ST cross and from 15.05 to 24.78 in the HB cross. In cotreatment with IQF, the frequencies ranged from 30.10 to 30.65 in the ST cross and from 13.60 to 14.50 in the HB cross, whereas the frequencies obtained with DXR were 32.50 in the ST cross and 26.00 in the HB cross. In conclusion, the IQA has a synergistic effect, enhancing the genotoxicity of DXR in the ST cross and the HB cross, whereas the IQF has antigenotoxic effects in the HB cross.

Mutagenicity and genotoxicity of coal fly ash water leachate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, R.; Mukherjee, A.

2009-03-15

Fly ash is a by-product of coal-fired electricity generation plants. The prevalent practice of disposal is as slurry of ash and water to storage or ash ponds located near power stations. This has lain to waste thousands of hectares of land all over the world. Since leaching is often the cause of off-site contamination and pathway of introduction into the human environment, a study on the genotoxic effects of fly ash leachate is essential. Leachate prepared from the fly ash sample was analyzed for metal content, and tested for mutagenicity and genotoxicity. Analyses of metals show predominance of the metalsmore » - sodium, silicon, potassium, calcium, magnesium, iron, manganese, zinc, and sulphate. The Ames Salmonella mutagenicity assay, a short-term bacterial reverse mutation assay, was conducted on two-tester strains of Salmonella typhimurium strains TA97a and TA102. For genotoxicity, the alkaline version of comet assay on fly ash leachate was carried in vitro on human blood cells and in vivo on Nicotiana plants. The leachate was directly mutagenic and induced significantconcentration-dependent increases in DNA damage in whole blood cells, lymphocytes, and in Nicotiana plants. The comet parameters show increases in tail DNA percentage (%), tail length (mu m), and olive tail moment (arbitrary units). Our results indicate that leachate from fly ash dumpsites has the genotoxic potential and may lead to adverse effects on vegetation and on the health of exposed human populations.« less

Engineered biofiltration for the removal of disinfection by-product precursors and genotoxicity.

PubMed

McKie, Michael J; Taylor-Edmonds, Liz; Andrews, Susan A; Andrews, Robert C

2015-09-15

Disinfection by-products (DBPs) are formed when naturally occurring organic matter reacts with chlorine used in drinking water treatment, and DBPs formed in chlorinated drinking water samples have been shown to cause a genotoxic response. The objective of the current study was to further understand the principles of biofiltration and the resulting impacts on the formation of DBPs and genotoxicity. Pilot-scale systems were utilized to assess the performance of engineered biofilters enhanced with hydrogen peroxide, in-line coagulants, and nutrients when compared to passively operated biofilters and conventional treatment (coagulation, flocculation, sedimentation, non-biological filtration). Organic fractionation was completed using liquid chromatography-organic carbon detection (LC-OCD). Water samples were chlorinated after collection and examined for the removal of trihalomethane (THM), haloacetic acid (HAA), and adsorbable organic halide (AOX) precursors. Additionally, the formation potential of two halogenated furanones, 3-chloro-4(dichloromethyl)-2(5H)-furanone (MX) and mucochloric acid (MCA), and genotoxicity was determined. Biofiltration was shown to preferentially remove more DBP precursors than dissolved organic carbon (DOC). Formation potential of the unregulated DBPs, including MX and MCA, and genotoxic response was shown to be correlated to THM formation. These results infer that monitoring for THMs and HAAs provide insight to the formation of more mutagenic DBPs such as halogenated furanones, and that biofiltration may preferentially remove precursors to DBPs at a rate exceeding the removal of DOC. Copyright © 2015 Elsevier Ltd. All rights reserved.

Senescence-Associated Secretory Phenotypes Reveal Cell-Nonautonomous Functions of Oncogenic RAS and the p53 Tumor Suppressor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coppé, Jean-Philippe; Patil, Christopher; Rodier, Francis

2008-10-24

Cellular senescence suppresses cancer by arresting cell proliferation, essentially permanently, in response to oncogenic stimuli, including genotoxic stress. We modified the use of antibody arrays to provide a quantitative assessment of factors secreted by senescent cells. We show that human cells induced to senesce by genotoxic stress secrete myriad factors associated with inflammation and malignancy. This senescence-associated secretory phenotype (SASP) developed slowly over several days and only after DNA damage of sufficient magnitude to induce senescence. Remarkably similar SASPs developed in normal fibroblasts, normal epithelial cells, and epithelial tumor cells after genotoxic stress in culture, and in epithelial tumor cellsmore » in vivo after treatment of prostate cancer patients with DNA-damaging chemotherapy. In cultured premalignant epithelial cells, SASPs induced an epithelial-mesenchyme transition and invasiveness, hallmarks of malignancy, by a paracrine mechanism that depended largely on the SASP factors interleukin (IL)-6 and IL-8. Strikingly, two manipulations markedly amplified, and accelerated development of, the SASPs: oncogenic RAS expression, which causes genotoxic stress and senescence in normal cells, and functional loss of the p53 tumor suppressor protein. Both loss of p53 and gain of oncogenic RAS also exacerbated the promalignant paracrine activities of the SASPs. Our findings define a central feature of genotoxic stress-induced senescence. Moreover, they suggest a cell-nonautonomous mechanism by which p53 can restrain, and oncogenic RAS can promote, the development of age-related cancer by altering the tissue microenvironment.« less

Detection of genotoxic effects of drinking water disinfection by-products using Vicia faba bioassay.

PubMed

Hu, Yu; Tan, Li; Zhang, Shao-Hui; Zuo, Yu-Ting; Han, Xue; Liu, Na; Lu, Wen-Qing; Liu, Ai-Lin

2017-01-01

Plant-based bioassays have gained wide use among the toxicological and/or ecotoxicological assessment procedures because of their simplicity, sensitivity, low cost, and reliability. The present study describes the use of Vicia faba (V. faba) micronucleus (MN) test and V. faba comet assay in the evaluation of the genotoxic potential of disinfection by-products (DBPs) commonly found in chlorine-disinfected drinking water. Five haloacetic acids and three halogenated acetonitriles were chosen as representatives of DBPs in this study because they are of potentially great public health risk. Results of the MN test indicated that monochloroacetic acid (MCA), monobromoacetic acid (MBA), dichloroacetic acid (DCA), dibromoacetic acid (DBA), trichloroacetic acid (TCA), and trichloroacetonitrile (TCAN) caused a statistically significant increase in MN frequency in V. faba root tip cells. However, no genotoxic response was observed for dichloroacetonitrile (DCAN) and dibromoacetonitrile (DBAN). Results of the comet assay showed that all tested DBPs induced a statistically significant increase in genomic DNA damage to V. faba root tip cells. On considering the capacity to detect genomic damage of a different nature, we suggest that a combination of V. faba MN test and V. faba comet assay is a useful tool for the detection of genotoxic effects of DBPs. It is worthy of assessing the feasibility of using V. faba comet assay combined with V. faba MN test to screen for the genotoxic activity of chlorinated drinking water in future work.

In vivo genotoxicity evaluation of an artichoke (Cynara scolymus L.) aqueous extract.

PubMed

Zan, Meriele A; Ferraz, Alexandre B F; Richter, Marc F; Picada, Jaqueline N; de Andrade, Heloisa H R; Lehmann, Mauricio; Dihl, Rafael R; Nunes, Emilene; Semedo, Juliane; Da Silva, Juliana

2013-02-01

The Cynara scolymus (artichoke) is widely consumed as tea or food and shows important therapeutic properties. However, few studies have assessed the possible toxic effects of artichoke extracts. This study evaluates genotoxic and mutagenic activities of artichoke leaf aqueous extract in mice using the comet assay and the micronucleus test. Leaf extracts were given by gavage (500 mg/kg, 1000 mg/kg, and 2000 mg/kg) for 3 consecutive days. Extract composition was investigated using phytochemical screening and high-performance liquid chromatography (HPLC). In addition, antioxidant capacity was analyzed through the diphenyl-picrylhydrazyl (DPPH) and xanthine oxidase assay. Phytochemical screening detected the presence of phenolic compounds, flavonoids, and saponins. HPLC analyses indicated the presence of chlorogenic acid, caffeic acid, isoquercetrin, and rutin. Extracts showed a dose-dependent free radical scavenging effect of DPPH and an inhibitory effect of xanthine oxidase. The genotoxic results showed that leaf extracts did not increase micronuclei in peripheral blood cells. Compared to the control group, a significant increase in comet assay values was observed only in bone marrow of group treated with 2000 mg/kg, the highest dose tested, indicating that artichoke tea should be consumed with moderation. This is the first report of in vivo mutagenic and genotoxic evaluation with C. scolymus. The present study revealed leaf aqueous extract from artichoke shows lack of mutagenicity in vivo, and low genotoxicity and antioxidant activity; indicating that artichoke tea should be consumed with moderation. © 2013 Institute of Food Technologists®

Antibiotics and UV radiation induce competence for natural transformation in Legionella pneumophila.

PubMed

Charpentier, Xavier; Kay, Elisabeth; Schneider, Dominique; Shuman, Howard A

2011-03-01

Natural transformation by competence is a major mechanism of horizontal gene transfer in bacteria. Competence is defined as the genetically programmed physiological state that enables bacteria to actively take up DNA from the environment. The conditions that signal competence development are multiple and elusive, complicating the understanding of its evolutionary significance. We used expression of the competence gene comEA as a reporter of competence development and screened several hundred molecules for their ability to induce competence in the freshwater living pathogen Legionella pneumophila. We found that comEA expression is induced by chronic exposure to genotoxic molecules such as mitomycin C and antibiotics of the fluoroquinolone family. These results indicated that, in L. pneumophila, competence may be a response to genotoxic stress. Sunlight-emitted UV light represents a major source of genotoxic stress in the environment and we found that exposure to UV radiation effectively induces competence development. For the first time, we show that genetic exchanges by natural transformation occur within an UV-stressed population. Genotoxic stress induces the RecA-dependent SOS response in many bacteria. However, genetic and phenotypic evidence suggest that L. pneumophila lacks a prototypic SOS response and competence development in response to genotoxic stress is RecA independent. Our results strengthen the hypothesis that competence may have evolved as a DNA damage response in SOS-deficient bacteria. This parasexual response to DNA damage may have enabled L. pneumophila to acquire and propagate foreign genes, contributing to the emergence of this human pathogen.

Comparison of DNA damage in human-derived hepatoma line (HepG2) exposed to the fifteen drinking water disinfection byproducts using the single cell gel electrophoresis assay.

PubMed

Zhang, Li; Xu, Liang; Zeng, Qiang; Zhang, Shao-Hui; Xie, Hong; Liu, Ai-Lin; Lu, Wen-Qing

2012-01-24

Disinfection of drinking water reduces pathogenic infection, but generates disinfection by-products (DBPs) in drinking water. In this study, the effect of fifteen DBPs on DNA damage in human-derived hepatoma line (HepG2) was investigated by the single cell gel electrophoresis (SCGE) assay. These fifteen DBPs are: four trihalomethanes (THMs), six haloacetic acides (HAAs), three haloacetonitriles (HANs), 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), and chloral hydrate (CH). Based on the minimal effective concentration (MEC) at which DBPs induced significant increase in olive tail moment (OTM), the rank order of DNA-damaging potency is: bromodichloromethane (BDCM)>dibromochloromethane (DBCM)>tribromomethane (TBM)>trichloromethane (TCM) of the four THMs; iodoacetic acid (IA)>bromoacetic acid (BA)>dibromoacetic acid (DBA)>dichloracetic acid (DCA)>trichloroacetic acid (TCA) of the five HAAs; dibromoacetonitrile (DBN)approximately dichloroacetonitrile (DCN)>trichloroacetonitrile (TCN) of the three HANs. The DNA damaging potency of MX and CH is similar to TCA and DCA, respectively. IA is the most genotoxic DBP in the fifteen DBPs, followed by BA. Chloroacetic acid (CA) is not genotoxic in this assay. Our findings indicated that HepG2/SCGE is a sensitive tool to evaluate the genotoxicity of DBPs and iodinated DBPs are more genotoxic than brominated DBPs, but chlorinated DBPs are less genotoxic than brominated DBPs. © 2011 Elsevier B.V. All rights reserved.

Genomic phenotyping by barcode sequencing broadly distinguishes between alkylating agents, oxidizing agents, and non-genotoxic agents, and reveals a role for aromatic amino acids in cellular recovery after quinone exposure.

PubMed

Svensson, J Peter; Quirós Pesudo, Laia; McRee, Siobhan K; Adeleye, Yeyejide; Carmichael, Paul; Samson, Leona D

2013-01-01

Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N'-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic 'barcode', were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput 'barcode' sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised.

Genomic Phenotyping by Barcode Sequencing Broadly Distinguishes between Alkylating Agents, Oxidizing Agents, and Non-Genotoxic Agents, and Reveals a Role for Aromatic Amino Acids in Cellular Recovery after Quinone Exposure

PubMed Central

Svensson, J. Peter; Quirós Pesudo, Laia; McRee, Siobhan K.; Adeleye, Yeyejide; Carmichael, Paul; Samson, Leona D.

2013-01-01

Toxicity screening of compounds provides a means to identify compounds harmful for human health and the environment. Here, we further develop the technique of genomic phenotyping to improve throughput while maintaining specificity. We exposed cells to eight different compounds that rely on different modes of action: four genotoxic alkylating (methyl methanesulfonate (MMS), N-Methyl-N-nitrosourea (MNU), N,N′-bis(2-chloroethyl)-N-nitroso-urea (BCNU), N-ethylnitrosourea (ENU)), two oxidizing (2-methylnaphthalene-1,4-dione (menadione, MEN), benzene-1,4-diol (hydroquinone, HYQ)), and two non-genotoxic (methyl carbamate (MC) and dimethyl sulfoxide (DMSO)) compounds. A library of S. cerevisiae 4,852 deletion strains, each identifiable by a unique genetic ‘barcode’, were grown in competition; at different time points the ratio between the strains was assessed by quantitative high throughput ‘barcode’ sequencing. The method was validated by comparison to previous genomic phenotyping studies and 90% of the strains identified as MMS-sensitive here were also identified as MMS-sensitive in a much lower throughput solid agar screen. The data provide profiles of proteins and pathways needed for recovery after both genotoxic and non-genotoxic compounds. In addition, a novel role for aromatic amino acids in the recovery after treatment with oxidizing agents was suggested. The role of aromatic acids was further validated; the quinone subgroup of oxidizing agents were extremely toxic in cells where tryptophan biosynthesis was compromised. PMID:24040048

Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm).

PubMed

Han, So-Ri; Yun, Eun-Young; Kim, Ji-Young; Hwang, Jae Sam; Jeong, Eun Ju; Moon, Kyoung-Sik

2014-06-01

The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions.

Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm)

PubMed Central

Han, So-Ri; Yun, Eun-Young; Kim, Ji-Young; Hwang, Jae Sam; Jeong, Eun Ju

2014-01-01

The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions. PMID:25071922

Marine ecotoxicity of nitramines, transformation products of amine-based carbon capture technology.

PubMed

Coutris, Claire; Macken, Ailbhe L; Collins, Andrew R; El Yamani, Naouale; Brooks, Steven J

2015-09-15

In the context of reducing CO2 emissions to the atmosphere, chemical absorption with amines is emerging as the most advanced technology for post-combustion CO2 capture from exhaust gases of fossil fuel power plants. Despite amine solvent recycling during the capture process, degradation products are formed and released into the environment, among them aliphatic nitramines, for which the environmental impact is unknown. In this study, we determined the acute and chronic toxicity of two nitramines identified as important transformation products of amine-based carbon capture, dimethylnitramine and ethanolnitramine, using a multi-trophic suite of bioassays. The results were then used to produce the first environmental risk assessment for the marine ecosystem. In addition, the in vivo genotoxicity of nitramines was studied by adapting the comet assay to cells from experimentally exposed fish. Overall, based on the whole organism bioassays, the toxicity of both nitramines was considered to be low. The most sensitive response to both compounds was found in oysters, and dimethylnitramine was consistently more toxic than ethanolnitramine in all bioassays. The Predicted No Effect Concentrations for dimethylnitramine and ethanolnitramine were 0.08 and 0.18 mg/L, respectively. The genotoxicity assessment revealed contrasting results to the whole organism bioassays, with ethanolnitramine found to be more genotoxic than dimethylnitramine by three orders of magnitude. At the lowest ethanolnitramine concentration (1mg/L), 84% DNA damage was observed, whereas 100mg/L dimethylnitramine was required to cause 37% DNA damage. The mechanisms of genotoxicity were also shown to differ between the two compounds, with oxidation of the DNA bases responsible for over 90% of the genotoxicity of dimethylnitramine, whereas DNA strand breaks and alkali-labile sites were responsible for over 90% of the genotoxicity of ethanolnitramine. Fish exposed to >3mg/L ethanolnitramine had virtually no DNA left in their red blood cells. Copyright © 2015 Elsevier B.V. All rights reserved.

The role of natural indigo dye in alleviation of genotoxicity of sodium dithionite as a reducing agent.

PubMed

Bektaş, İdris; Karaman, Şengül; Dıraz, Emel; Çelik, Mustafa

2016-12-01

Indigo blue is a natural dye used for thousands of years by civilizations to dye fabric blue and it is naturally obtained from Isatis tinctoria. I. tinctoria is not only used for extraction of indigo blue color but also used medicinally in Traditional Chinese Medicine because of its active compounds. Sodium dithionite (Na 2 S 2 O 4 ) is used in dye bath for indigo blue extraction, but this reducing agent and its derivatives are major pollutants of textile industry and subsequently have hazardous influences on public health. Herein, the present study was designed to obtain the high yield of natural indigo dye but with low possible toxic effect. In this context, genotoxic effects of particular combinations of natural dye solutions obtained from Isatis tinctoria subsp. tomentolla with Na 2 S 2 O 4 as reducing agent were investigated. Dye solutions were obtained using two different pH levels (pH 9 and 11) and three different concentrations of Na 2 S 2 O 4 (2.5, 5 and 10 mg/ml). In addition to the dye solutions and reducing agent, aqueous extracts of I. tinctoria were assessed for their genotoxicity on human lymphocytes. For in vitro testing of genotoxicity, chromosomal aberrations (CAs), sister chromatid exchanges (SCEs) and mitotic indexes (MI) assays were used. Accordingly, Na 2 S 2 O 4 caused significant increases in CA and SCE as well decrease in MI but the genotoxic effects of sodium dithionite were reduced with natural indigo dye. As a result, aqueous extracts of Isatis leaves removed the toxic effects of sodium dithionite and showed anti-genotoxic effect. For the optimal and desired quality but with less toxic effects of natural dye, 2.5 mg/ml (for wool yarn) and 5 mg/ml (for cotton yarn) of Na 2 S 2 O 4 doses were found to be the best doses for reduction in the dye bath at Ph 9.

Integration of metabolic activation with a predictive toxicogenomics signature to classify genotoxic versus nongenotoxic chemicals in human TK6 cells

PubMed Central

Buick, Julie K.; Moffat, Ivy; Williams, Andrew; Swartz, Carol D.; Recio, Leslie; Hyduke, Daniel R.; Li, Heng‐Hong; Fornace, Albert J.; Aubrecht, Jiri

2015-01-01

The use of integrated approaches in genetic toxicology, including the incorporation of gene expression data to determine the molecular pathways involved in the response, is becoming more common. In a companion article, a genomic biomarker was developed in human TK6 cells to classify chemicals as genotoxic or nongenotoxic. Because TK6 cells are not metabolically competent, we set out to broaden the utility of the biomarker for use with chemicals requiring metabolic activation. Specifically, chemical exposures were conducted in the presence of rat liver S9. The ability of the biomarker to classify genotoxic (benzo[a]pyrene, BaP; aflatoxin B1, AFB1) and nongenotoxic (dexamethasone, DEX; phenobarbital, PB) agents correctly was evaluated. Cells were exposed to increasing chemical concentrations for 4 hr and collected 0 hr, 4 hr, and 20 hr postexposure. Relative survival, apoptosis, and micronucleus frequency were measured at 24 hr. Transcriptome profiles were measured with Agilent microarrays. Statistical modeling and bioinformatics tools were applied to classify each chemical using the genomic biomarker. BaP and AFB1 were correctly classified as genotoxic at the mid‐ and high concentrations at all three time points, whereas DEX was correctly classified as nongenotoxic at all concentrations and time points. The high concentration of PB was misclassified at 24 hr, suggesting that cytotoxicity at later time points may cause misclassification. The data suggest that the use of S9 does not impair the ability of the biomarker to classify genotoxicity in TK6 cells. Finally, we demonstrate that the biomarker is also able to accurately classify genotoxicity using a publicly available dataset derived from human HepaRG cells. Environ. Mol. Mutagen. 56:520–534, 2015. © 2015 The Authors. Environmental and Molecular Mutagenesis Published by Wiley Periodicals, Inc. PMID:25733247

Health care industries: potential generators of genotoxic waste.

PubMed

Sharma, Pratibha; Kumar, Manish; Mathur, N; Singh, A; Bhatnagar, P; Sogani, M

2013-08-01

Health care waste includes all the waste generated by health care establishments, research facilities, and laboratories. This constitutes a variety of chemical substances, such as pharmaceuticals, radionuclides, solvents, and disinfectants. Recently, scientists and environmentalists have discovered that wastewater produced by hospitals possesses toxic properties due to various toxic chemicals and pharmaceuticals capable of causing environmental impacts and even lethal effects to organisms in aquatic ecosystems. Many of these compounds resist normal wastewater treatment and end up in surface waters. Besides aquatic organisms, humans can be exposed through drinking water produced from contaminated surface water. Indeed, some of the substances found in wastewaters are genotoxic and are suspected to be potential contributors to certain cancers. The aim of this study was to evaluate the genotoxic and cytotoxic potential of wastewaters from two hospitals and three clinical diagnostic centers located in Jaipur (Rajasthan State), India using the prokaryotic Salmonella mutagenicity assay (Ames assay) and the eukaryotic Saccharomyces cerevisiae respiration inhibition assay. In the Ames assay, untreated wastewaters from both of the health care sectors resulted in significantly increased numbers of revertant colonies up to 1,000-4,050 as measured by the Salmonella typhimurium TA98 and TA100 strains (with and without metabolic activation) after exposure to undiluted samples, which indicated the highly genotoxic nature of these wastewaters. Furthermore, both hospital and diagnostic samples were found to be highly cytotoxic. Effective concentrations at which 20 % (EC20) and 50 % (EC50) inhibition of the respiration rate of the cells occurred ranged between ~0.00 and 0.52 % and between 0.005 and 41.30 % (calculated with the help of the MS excel software XLSTAT 2012.1.01; Addinsoft), respectively, as determined by the S. cerevisiae assay. The results indicated that hospital wastewaters contain genotoxic and cytotoxic components. In addition, diagnostic centers also represent small but significant sources of genotoxic and cytotoxic wastes.

Pharmacological inhibition of Polo Like Kinase 2 (PLK2) does not cause chromosomal damage or result in the formation of micronuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitzgerald, Kent, E-mail: Kent.fitzgerald@elan.com; Bergeron, Marcelle, E-mail: Marcelle.bergeron@elan.com; Willits, Christopher, E-mail: Chris.willits@elan.com

2013-05-15

Polo Like Kinase 2 (PLK2) phosphorylates α-synuclein and is considered a putative therapeutic target for Parkinson's disease. Several lines of evidence indicate that PLK2 is involved with proper centriole duplication and cell cycle regulation, inhibition of which could impact chromosomal integrity during mitosis. The objectives of the series of experiments presented herein were to assess whether specific inhibition of PLK2 is genotoxic and determine if PLK2 could be considered a tractable pharmacological target for Parkinson's disease. Several selective PLK2 inhibitors, ELN 582175 and ELN 582646, and their inactive enantiomers, ELN 582176 and ELN 582647, did not significantly increase the numbermore » of micronuclei in the in vitro micronucleus assay. ELN 582646 was administered to male Sprague Dawley rats in an exploratory 14-day study where flow cytometric analysis of peripheral blood identified a dose-dependent increase in the number of micronucleated reticulocytes. A follow-up investigative study demonstrated that ELN 582646 administered to PLK2 deficient and wildtype mice significantly increased the number of peripheral micronucleated reticulocytes in both genotypes, suggesting that ELN 582646-induced genotoxicity is not through the inhibition of PLK2. Furthermore, significant reduction of retinal phosphorylated α-synuclein levels was observed at three non-genotoxic doses, additional data to suggest that pharmacological inhibition of PLK2 is not the cause of the observed genotoxicity. These data, in aggregate, indicate that PLK2 inhibition is a tractable CNS pharmacological target that does not cause genotoxicity at doses and exposures that engage the target in the sensory retina. - Highlights: • Active and inactive enantiomers test negative in the in vitro micronucleus test. • ELN 582646 significantly increased micronuclei at 100 and 300 mg/kg/day doses. • ELN 582646 significantly increased micronuclei in PLK2 knockout mice. • ELN 582646 decreased phosphorylation of alpha-synuclein at non-genotoxic doses.« less

Retrospective analysis of the mutagenicity/genotoxicity data of the cosmetic ingredients present on the Annexes of the Cosmetic EU legislation (2000-12).

PubMed

Ates, Gamze; Doktorova, Tatyana Y; Pauwels, Marleen; Rogiers, Vera

2014-03-01

To evaluate the mutagenicity/genotoxicity of cosmetic ingredients at the regulatory level, usually a battery of three in vitro tests is applied. This battery, designed to be very sensitive, produces a high number of positive results, imposing the need for in vivo follow-up testing to clear the substance under study. In Europe, the use of experimental animals has become impossible for cosmetic ingredients due to the implementation of animal testing and marketing bans. Consequently, the possibility to 'de-risk' substances with positive in vitro results disappear and potentially safe cosmetic substances will be lost for the EU market unless currently used in vitro assays can be adapted or new non-animal mutagenicity/genotoxicity studies become available. Described strategies to improve the specificity of existing in vitro assays include optimisation of the used cell type and cytotoxicity assay and lowering of the applied top concentration. A reduction of the number of tests in the battery from three to two also has been suggested. In this study, the performance of the 'standard' in vitro mutagenicity/genotoxicity testing battery is analysed for a number of cosmetic ingredients. We composed a database with toxicological information on 249 cosmetic ingredients, mainly present on the Annexes of the European cosmetic legislation. Results revealed that the in vitro mutagenicity/genotoxicity tests showed a low specificity for the cosmetic ingredients concerned, comparable to the specificity published for chemicals. Non-confirmed or 'misleading' positive results amounted up to 93% for the in vitro test batteries. The cell type and top concentrations did not have a major impact on the specificity. With respect to cytotoxicity determinations, different end points were used, potentially leading to different testing concentrations, suggesting the need for a consensus in this matter. Overall, the results of this retrospective analysis point to an urgent need of better regulatory strategies to assess the potential mutagenicity/genotoxicity of cosmetic ingredients.

Tests for genotoxicity and mutagenicity of furan and its metabolite cis-2-butene-1,4-dial in L5178Y tk+/- mouse lymphoma cells.

PubMed

Kellert, Marco; Brink, Andreas; Richter, Ingrid; Schlatter, Josef; Lutz, Werner K

2008-12-08

Furan is found in various food items and is cytotoxic and carcinogenic in the liver of rats and mice. Metabolism of furan includes the formation of an unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). In view of the multifunctional electrophilic reactivity of BDA, adduct formation with protein and DNA may explain some of the toxic effects. Short-term tests for genotoxicity of furan in mammalian cells are inconclusive, little is known for BDA. We investigated BDA generated by hydrolysis of 2,5-diacetoxy-2,5-dihydrofuran for genotoxicity in L5178Y tk+/- mouse lymphoma cells using standard procedures for the comet assay, the micronucleus test, and the mouse lymphoma thymidine kinase gene mutation assay, using 4-h incubation periods. Cytotoxicity was remarkable: cell viability at concentrations>or=50 microM was reduced to <50%. In the dose range up to 25 microM, viability was >90%. Measures of comet-tail length and thymidine-kinase mutant frequency were increased 1.6- and 2.4-fold above control, respectively. Analysis of three fully independent replicates with a linear mixed-effects model showed a highly significant increase with concentration for both endpoints. Compared to methyl methanesulfonate used as a positive control, BDA was of similar potency with respect to genotoxicity, but it was much more cytotoxic. Furan added to cell cultures at doses that resulted in time-averaged effective concentrations of up to 3100 microM was neither cytotoxic nor genotoxic. A potential cross-linking activity of BDA was investigated by checking whether gamma radiation-induced DNA migration in the comet assay could be reduced by pre-treatment with BDA. In contrast to the effect of the positive control glutaraldehyde, BDA treatment did not reduce the comet tail length. On the contrary, an increase was observed at >or=100 microM BDA, which was attributable to early apoptotic cells. Although BDA was found to be a relatively potent genotoxic agent in terms of the concentration necessary to double the background measures, cytotoxicity strongly limited the concentration range that produced interpretable results. This may explain some of the inconclusive results and indicates that non-genotoxic effects must be taken into account in the discussion of the modes of toxic and carcinogenic action of furan.

Effects of light on the cytotoxicity and genotoxicity of benzo(a)pyrene and an oil refinery effluent in the newt

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez, M.; l`Haridon, J.

1994-12-31

The genotoxicity and/or toxicity of benzo(a)pyrene (BaP) were evaluated under different lighting conditions in larvae and embryos of the newt Pleurodeles waltl. Visible light alone, UVA alone, or BaP alone had no toxic effects on the larvae. Conversely, toxic effects were observed in animals exposed to BaP + daylight, or BaP + UVA. The genotoxicity of BaP (50 ppb) was halved by its previous exposure to UVA, and was abolished at the lowest concentration (12.5 ppb). In other experiments, the larvae were exposed alternatively to BaP or Irr BaP (18 hours in dark) and UVA (6 hr in water), everymore » day for 8 days. All animals that had accumulated non-irradiated BaP (50 ppb) showed signs of severe toxicity, and 90% died before the end of the test. On the other hand, irradiated BaP (50 ppb) was a 4-fold less toxic and half as genotoxic as non-irradiated BaP. In addition, exposure of the animals to UVA alone for 4 days prior to treatment with BaP did not affect the genotoxicity or toxicity of this hydrocarbon. In the dark, the embryotoxicity of BaP was markedly attenuated by the presence of the jelly coats. Although UVA alone did not affect growth of the embryos, the toxicity of BaP was enhanced by the combined action of the two agents together or in succession (BaP + UVA or BaP then UVA). Larvae were treated with an oil refinery effluent (EF). At 125 ml/l, EF was not found to be genotoxic in the dark. However, in animals exposed to both EF and UVA, there was a progressive increase in level of micronucleated erythrocytes with increasing duration of daily exposure to UVA. Moreover, the genotoxic potential of irradiated EF + UVA was systematically below that of non-irradiated EF + UVA for all durations of exposure to ultraviolet light. Irradiation of this type of effluent might help reduce its harmful effects on aquatic species. Our results also suggest that metabolic activation is not necessary for hydrocarbons to induce toxic effects. 51 refs., 5 tabs., 3 figs.« less

THE EFFECTS OF HEAT SHOCK PROTEIN 70 (HSP70) AND EXPOSURE PROTOCOL ON ARSENITE INDUCED GENOTOXICITY

EPA Science Inventory

The Effects of Heat Shock Protein 70 (Hsp70) and Exposure Protocol on Arsenite Induced Genotoxicity

Barnes, J.A.1,2, Collins, B.W.2, Dix, D.J.3 and Allen J.W2.
1National Research Council, 2Environmental Carcinogenesis Division, 3Reproductive Toxicology Division, Office...

Application of the Margin of Exposure (MoE) Approach to Substances in Food that are Genotoxic and Carcinogenic Example: Benzo[a]pyrene and polycyclic aromatic hydrocarbons

EPA Science Inventory

This paper presents the work of an expert group established by the International Life Sciences Institute - European branch (ILSI Europe) to follow up the recommendations of an international conference on "Risk Assessment of Compounds that are both Genotoxic and Carcinogenic: New ...

GENOTOXICITY OF TEN CIGARETTE SMOKE CONDENSATES IN FOUR TEST SYSTEMS: COMPARISONS BETWEEN ASSAYS AND CONDENSATES

EPA Science Inventory

What is the study?
This the first assessment of a set of cigarette smoke condensates from a range of cigarette types in a variety (4) of short-term genotoxicity assays.
Why was it done?
No such comparative study of cigarette smoke condensates has been reported. H...

ARSENIC (III) METHYLATED SPECIES REACT WITH DNA DIRECTLY AND COULD BE PROXIMATED/ULTIMATE GENOTOXIC FORMS OF ARSENIC

EPA Science Inventory

ARSENIC(III) METHYLATED SPECIES REACT WITH DNA DIRECTL Y AND COULD BE PROXIMATE/ULTIMATE GENOTOXIC FORMS OF ARSENIC


Arsenite and arsenate (iAs, inorganic arsenic) have been thought to act as genotoxicants without reacting directly with DNA; neither iAs nor As(V) m...

Decrease of 5-hydroxymethylcytosine in rat liver with subchronic exposure to genotoxic carcinogens riddelliine and aristolochic acid.

PubMed

Lian, Christine Guo; Xu, Shuyun; Guo, Weimin; Yan, Jian; Frank, Maximilian Y M; Liu, Robert; Liu, Cynthia; Chen, Ying; Murphy, George F; Chen, Tao

2015-11-01

The level of 5-hydroxymethylcytosine (5-hmC) converted by ten-eleven translocation (TET) family is decreased in cancers. However, whether 5-hmC level is perturbed in early stages of carcinogenesis caused by genotoxic carcinogens is not defined. 5-hmC levels and TET2 expression were measured in liver of rats treated with genotoxic carcinogens, riddelliine, or aristolochic acid. Levels of 5-hmC and TET2 expression decreased in the liver of the carcinogens-treated rats. Loss of 5-hmC correlates well with documented induction of genetic mutations by the carcinogens, suggesting that TET2-mediated 5-hydroxymethylation plays an epigenetic role in early state of carcinogenesis. © 2014 Wiley Periodicals, Inc.

Decrease of 5-Hydroxymethylcytosine in Rat Liver with Subchronic Exposure to Genotoxic Carcinogens Riddelliine and Aristolochic Acid

PubMed Central

Lian, Christine Guo; Xu, Shuyun; Guo, Weimin; Yan, Jian; Frank, Maximilian Y M; Liu, Robert; Liu, Cynthia; Chen, Ying; Murphy, George F.; Chen, Tao

2018-01-01

The level of 5-hydroxymethylcytosine (5-hmC) converted by ten-eleven translocation (TET) family is decreased in cancers. However, whether 5-hmC level is perturbed in early stages of carcinogenesis caused by genotoxic carcinogens is not defined. 5-hmC levels and TET2 expression were measured in liver of rats treated with genotoxic carcinogens, riddelliine, or aristolochic acid. Levels of 5-hmC and TET2 expression decreased in the liver of the carcinogens-treated rats. Loss of 5-hmC correlates well with documented induction of genetic mutations by the carcinogens, suggesting that TET2-mediated 5-hydroxymethylation plays an epigenetic role in early state of carcinogenesis. PMID:25154389

The resolving power of in vitro genotoxicity assays for cigarette smoke particulate matter.

PubMed

Scott, K; Saul, J; Crooks, I; Camacho, O M; Dillon, D; Meredith, C

2013-06-01

In vitro genotoxicity assays are often used to compare tobacco smoke particulate matter (PM) from different cigarettes. The quantitative aspect of the comparisons requires appropriate statistical methods and replication levels, to support the interpretation in terms of power and significance. This paper recommends a uniform statistical analysis for the Ames test, mouse lymphoma mammalian cell mutation assay (MLA) and the in vitro micronucleus test (IVMNT); involving a hierarchical decision process with respect to slope, fixed effect and single dose comparisons. With these methods, replication levels of 5 (Ames test TA98), 4 (Ames test TA100), 10 (Ames test TA1537), 6 (MLA) and 4 (IVMNT) resolved a 30% difference in PM genotoxicity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Three-Dimensional Transgenic Cell Models to Quantify Space Genotoxic Effects

NASA Technical Reports Server (NTRS)

Gonda, S.; Wu, H.; Pingerelli, P.; Glickman, B.

2000-01-01

In this paper we describe a three-dimensional, multicellular tissue-equivalent model, produced in NASA-designed, rotating wall bioreactors using mammalian cells engineered for genomic containment of mUltiple copies of defined target genes for genotoxic assessment. The Rat 2(lambda) fibroblasts (Stratagene, Inc.) were genetically engineered to contain high-density target genes for mutagenesis. Stable three-dimensional, multicellular spheroids were formed when human mammary epithelial cells and Rat 2(lambda) fibroblasts were cocultured on Cytodex 3 Beads in a rotating wall bioreactor. The utility of this spheroidal model for genotoxic assessment was indicated by a linear dose response curve and by results of gene sequence analysis of mutant clones from 400micron diameter spheroids following low-dose, high-energy, neon radiation exposure

Genotoxicity of gemfibrozil in the gilthead seabream (Sparus aurata).

PubMed

Barreto, A; Luis, L G; Soares, A M V M; Paíga, P; Santos, L H M L M; Delerue-Matos, C; Hylland, K; Loureiro, S; Oliveira, M

2017-09-01

Widespread use of pharmaceuticals and suboptimal wastewater treatment have led to increased levels of these substances in aquatic ecosystems. Lipid-lowering drugs such as gemfibrozil, which are among the most abundant human pharmaceuticals in the environment, may have deleterious effects on aquatic organisms. We examined the genotoxicity of gemfibrozil in a fish species, the gilthead seabream (Sparus aurata), which is commercially important in southern Europe. Following 96-h waterborne exposure, molecular (erythrocyte DNA strand breaks) and cytogenetic (micronuclei and other nuclear abnormalities in cells) endpoints were measured. Gemfibrozil was positive in both endpoints, at environmentally relevant concentrations, a result that raises concerns about the potential genotoxic effects of the drug in recipient waters. Copyright © 2017 Elsevier B.V. All rights reserved.

Mathematical models for exploring different aspects of genotoxicity and carcinogenicity databases.

PubMed

Benigni, R; Giuliani, A

1991-12-01

One great obstacle to understanding and using the information contained in the genotoxicity and carcinogenicity databases is the very size of such databases. Their vastness makes them difficult to read; this leads to inadequate exploitation of the information, which becomes costly in terms of time, labor, and money. In its search for adequate approaches to the problem, the scientific community has, curiously, almost entirely neglected an existent series of very powerful methods of data analysis: the multivariate data analysis techniques. These methods were specifically designed for exploring large data sets. This paper presents the multivariate techniques and reports a number of applications to genotoxicity problems. These studies show how biology and mathematical modeling can be combined and how successful this combination is.

Update on the Use of C1-Esterase Inhibitor Replacement Therapy in the Acute and Prophylactic Treatment of Hereditary Angioedema.

PubMed

Henry Li, H; Riedl, Marc; Kashkin, Jay

2018-06-16

In the vast majority of patients with hereditary angioedema (HAE), angioedema attacks are due to the quantitative or functional deficiency of C1-esterase inhibitor (C1-INH), which leads to increased vascular permeability and unregulated release of bradykinin. Exogenous administration of C1-INH is a rational way to restore the concentration and functional activity of this protein, regulate the release of bradykinin, and attenuate or prevent subcutaneous and submucosal edema associated with HAE. Recent international guidelines for the management of HAE include C1-INH as an option for acute treatment of HAE. In addition, these guidelines recommend C1-INH as first-line treatment for long-term prophylaxis and as the therapy of choice for short-term/preprocedural prophylaxis. Several C1-INH products are available, with approved indications varying across regions. For the acute treatment of HAE, both plasma-derived and recombinant C1-INH formulations have been shown to be effective and well tolerated in adolescents and adults with HAE, with onset of relief within 30 min to a few hours. Plasma-derived C1-INH is approved for use in children, and recombinant C1-INH is being evaluated in this population. Intravenous (IV) and subcutaneous (SC) formulations of C1-INH have been approved for routine prophylaxis to prevent HAE attacks in adolescents and adults. Both formulations when administered twice weekly have been shown to reduce the frequency and severity of HAE attacks. The SC formulation of C1-INH obviates the need for repeated venous access and may facilitate self-administration of HAE prophylaxis at home, as recommended in HAE treatment guidelines. As with most rare diseases, the costs of HAE treatment are high; however, the development of additional acute and prophylactic medications for HAE may result in competitive pricing and help drive down the costs of HAE treatment.

Impacts of discarded coffee waste on human and environmental health.

PubMed

Fernandes, A S; Mello, F V C; Thode Filho, S; Carpes, R M; Honório, J G; Marques, M R C; Felzenszwalb, I; Ferraz, E R A

2017-07-01

Coffee is one of the most widely consumed beverages throughout the world. So far, many studies have shown the properties of coffee beverages, but little is known about its impacts on human and environmental health from its discard in the environment. So, the present work aims to investigate the mutagenic, genotoxic, cytotoxic and ecotoxic effects of leached (LE) and solubilized (SE) extracts from coffee waste, simulating the disposal of this residue in landfills and via sewage systems, respectively. Chemical analyses were also carried out. LE and SE induced mutagenicity in the TA98 Salmonella strain with and without exogenous metabolization (S9). In the TA100 only SE induced mutagenicity, what was observed without S9. An increase in the frequency of micronuclei was observed in HepG2 cell line after 3 and 24h of exposure to both extracts. No cytotoxic effects were observed in HepG2 cells by WST-1 assay. The EC50 values for the LE and SE were 1.5% and 11.26% for Daphnia similis, 0.12% and 1.39% for Ceriodaphnia dubia and 6.0% and 5.5% for Vibrio fischeri, respectively. Caffeine and several transition metals were found in both extracts. Coffee waste discarded in the environment may pose a risk to human and environmental health, since this compound can cause DNA damage and present toxicity to aquatic organisms. Copyright © 2017 Elsevier Inc. All rights reserved.

Monocyclic aromatic amines as potential human carcinogens: old is new again

PubMed Central

Skipper, Paul L.; Kim, Min Young; Sun, H.-L. Patty; Wogan, Gerald N.; Tannenbaum, Steven R.

2010-01-01

Alkylanilines are a group of chemicals whose ubiquitous presence in the environment is a result of the multitude of sources from which they originate. Exposure assessments indicate that most individuals experience lifelong exposure to these compounds. Many alkylanilines have biological activity similar to that of the carcinogenic multi-ring aromatic amines. This review provides an overview of human exposure and biological effects. It also describes recent investigations into the biochemical mechanisms of action that lead to the assessment that they are most probably more complex than those of the more extensively investigated multi-ring aromatic amines. Not only is nitrenium ion chemistry implicated in DNA damage by alkylanilines but also reactions involving quinone imines and perhaps reactive oxygen species. Recent results described here indicate that alkylanilines can be potent genotoxins for cultured mammalian cells when activated by exogenous or endogenous phase I and phase II xenobiotic-metabolizing enzymes. The nature of specific DNA damage products responsible for mutagenicity remains to be identified but evidence to date supports mechanisms of activation through obligatory N-hydroxylation as well as subsequent conjugation by sulfation and/or acetylation. A fuller understanding of the mechanisms of alkylaniline genotoxicity is expected to provide important insights into the environmental and genetic origins of one or more human cancers and may reveal a substantial role for this group of compounds as potential human chemical carcinogens. PMID:19887514

Myeloid leukemia factor 1 regulates p53 by suppressing COP1 via COP9 signalosome subunit 3

PubMed Central

Yoneda-Kato, Noriko; Tomoda, Kiichiro; Umehara, Mari; Arata, Yukinobu; Kato, Jun-ya

2005-01-01

Myeloid leukemia factor 1 (MLF1) was first identified as the leukemic fusion protein NPM-MLF1 generated by the t(3;5)(q25.1;q34) chromosomal translocation. Although MLF1 expresses normally in a variety of tissues including hematopoietic stem cells and the overexpression of MLF1 correlates with malignant transformation in human cancer, little is known about how MLF1 is involved in the regulation of cell growth. Here we show that MLF1 is a negative regulator of cell cycle progression functioning upstream of the tumor suppressor p53. MLF1 induces p53-dependent cell cycle arrest in murine embryonic fibroblasts. This action requires a novel binding partner, subunit 3 of the COP9 signalosome (CSN3). A reduction in the level of CSN3 protein with small interfering RNA abrogated MLF1-induced G1 arrest and impaired the activation of p53 by genotoxic stress. Furthermore, ectopic MLF1 expression and CSN3 knockdown inversely affect the endogenous level of COP1, a ubiquitin ligase for p53. Exogenous expression of COP1 overcomes MLF1-induced growth arrest. These results indicate that MLF1 is a critical regulator of p53 and suggest its involvement in leukemogenesis through a novel CSN3–COP1 pathway. PMID:15861129

The role of metabolic activation of analgesics and non-steroidal anti-inflammatory drugs in the development of renal papillary necrosis and upper urothelial carcinoma.

PubMed

Bach, P H; Bridges, J W

1984-08-01

There has been no cogent hypothesis to explain the molecular basis of analgesic and non-steroidal anti-inflammatory drug (NSAID) associated renal papillary necrosis (RPN) and upper urothelial carcinoma (UUC). The microsomal cytochrome P-450 enzyme system may generate reactive intermediates which promote pathophysiological effects in the lung, liver and renal cortex, but the absence of P-450 activity in the medulla suggests that it is unlikely that similar events lead to RPN and UUC. Other enzymes (eg. peroxidases) convert substituted aromatics into benzoquinoneimines (an intermediate that has previously been defined in P-450-mediated toxicity). The medulla is rich in fatty acid peroxidases involved in the metabolism of arachidonic acid. NSAID and analgesics interact with key enzymes in this pathway, which could lead to the co-oxygenation of exogenous and endogenous compounds via the peroxidase, lipoxygenase, or prostaglandin hydroperoxidase enzymes. The generation of reactive molecules in the medulla could explain both RPN and UUC via the alkylation of macromolecules. The formation of free radicals would give rise to extensive lipid peroxidation, (there are large quantities of free polyunsaturated fatty acids in the medullary interstitial cells), an event of major potential importance to local cell destruction and genotoxic effects. At present this proposed mechanism of co-oxygenation offers the most attractive working hypothesis to explain the molecular pathogenesis of both RPN and UUC.

Impact of topical application of sulfur mustard on mice skin and distant organs DNA repair enzyme signature.

PubMed

Sauvaigo, Sylvie; Sarrazy, Fanny; Batal, Mohamed; Caillat, Sylvain; Pitiot, Benoit; Mouret, Stéphane; Cléry-Barraud, Cécile; Boudry, Isabelle; Douki, Thierry

2016-01-22

Sulfur mustard (SM) is a chemical warfare agent that, upon topical application, damages skin and reaches internal organs through diffusion in blood. Two major toxic consequences of SM exposure are inflammation, associated with oxidative stress, and the formation of alkylated DNA bases. In the present study, we investigated the impact of exposure to SM on DNA repair, using two different functional DNA repair assays which provide information on several Base Excision Repair (BER) and Excision/Synthesis Repair (ESR) activities. BER activities were reduced in all organs as early as 4h after exposure, with the exception of the defense systems against 8-oxo-guanine and hypoxanthine which were stimulated. Interestingly, the resulting BER intermediates could activate inflammation signals, aggravating the inflammation triggered by SM exposure and leading to increased oxidative stress. ESR activities were found to be mostly inhibited in skin, brain and kidneys. In contrast, in the lung there was a general increase in ESR activities. In summary, exposure to SM leads to a significant decrease in DNA repair in most organs, concomitant with the formation of DNA damage. These synergistic genotoxic effects are likely to participate in the high toxicity of this alkylating agent. Lungs, possibly better equipped with repair enzymes to handle exogenous exposure, are the exception. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Cells deficient in the FANC/BRCA pathway are hypersensitive to plasma levels of formaldehyde.

PubMed

Ridpath, John R; Nakamura, Ayumi; Tano, Keizo; Luke, April M; Sonoda, Eiichiro; Arakawa, Hiroshi; Buerstedde, Jean-Marie; Gillespie, David A F; Sale, Julian E; Yamazoe, Mitsuyoshi; Bishop, Douglas K; Takata, Minoru; Takeda, Shunichi; Watanabe, Masami; Swenberg, James A; Nakamura, Jun

2007-12-01

Formaldehyde is an aliphatic monoaldehyde and is a highly reactive environmental human carcinogen. Whereas humans are continuously exposed to exogenous formaldehyde, this reactive aldehyde is a naturally occurring biological compound that is present in human plasma at concentrations ranging from 13 to 97 micromol/L. It has been well documented that DNA-protein crosslinks (DPC) likely play an important role with regard to the genotoxicity and carcinogenicity of formaldehyde. However, little is known about which DNA damage response pathways are essential for cells to counteract formaldehyde. In the present study, we first assessed the DNA damage response to plasma levels of formaldehyde using chicken DT40 cells with targeted mutations in various DNA repair genes. Here, we show that the hypersensitivity to formaldehyde is detected in DT40 mutants deficient in the BRCA/FANC pathway, homologous recombination, or translesion DNA synthesis. In addition, FANCD2-deficient DT40 cells are hypersensitive to acetaldehyde, but not to acrolein, crotonaldehyde, glyoxal, and methylglyoxal. Human cells deficient in FANCC and FANCG are also hypersensitive to plasma levels of formaldehyde. These results indicate that the BRCA/FANC pathway is essential to counteract DPCs caused by aliphatic monoaldehydes. Based on the results obtained in the present study, we are currently proposing that endogenous formaldehyde might have an effect on highly proliferating cells, such as bone marrow cells, as well as an etiology of cancer in Fanconi anemia patients.

Damage pattern as a function of radiation quality and other factors.

PubMed

Burkart, W; Jung, T; Frasch, G

1999-01-01

An understanding of damage pattern in critical cellular structures such as DNA is an important prerequisite for a mechanistic assessment of primary radiation damage, its possible repair, and the propagation of residual changes in somatic and germ cells as potential contributors to disease or ageing. Important quantitative insights have been made recently on the distribution in time and space of critical lesions from direct and indirect action of ionizing radiation on mammalian cells. When compared to damage from chemicals or from spontaneous degradation, e.g. depurination or base deamination in DNA, the potential of even low-LET radiation to create local hot spots of damage from single particle tracks is of utmost importance. This has important repercussions on inferences from critical biological effects at high dose and dose rate exposure situations to health risks at chronic, low-level exposures as experienced in environmental and controlled occupational settings. About 10,000 DNA lesions per human cell nucleus and day from spontaneous degradation and chemical attack cause no apparent effect, but a dose of 4 Gy translating into a similar number of direct and indirect DNA breaks induces acute lethality. Therefore, single lesions cannot explain the high efficiency of ionizing radiation in the induction of mutation, transformation and loss of proliferative capacity. Clustered damage leading to poorly repairable double-strand breaks or even more complex local DNA degradation, correlates better with fixed damage and critical biological endpoints. A comparison with other physical, chemical and biological agents indicates that ionizing radiation is indeed set apart from these by its unique micro- and nano-dosimetric traits. Only a few other agents such as bleomycin have a similar potential to cause complex damage from single events. However, in view of the multi-stage mechanism of carcinogenesis, it is still an open question whether dose-effect linearity for complex primary DNA damage and resulting fixed critical cellular lesions translate into linearity for radiation-induced cancer. To solve this enigma, a quantitative assessment of all genotoxic and harmful non-genotoxic agents affecting the human body would be needed.

Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: A systematic literature review

PubMed Central

Chappell, Grace; Pogribny, Igor P.; Guyton, Kathryn Z.; Rusyn, Ivan

2016-01-01

Accumulating evidence suggests that epigenetic alterations play an important role in chemically-induced carcinogenesis. Although the epigenome and genome may be equally important in carcinogenicity, the genotoxicity of chemical agents and exposure-related transcriptomic responses have been more thoroughly studied and characterized. To better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints. Specifically, we searched for publications reporting epigenetic effects for the 28 agents and occupations included in Monograph Volume 100F of the International Agency for the Research on Cancer (IARC) that were classified as “carcinogenic to humans” (Group 1) with strong evidence of genotoxic mechanisms of carcinogenesis. We identified a total of 158 studies that evaluated epigenetic alterations for 12 of these 28 carcinogenic agents and occupations (1,3-butadiene, 4-aminobiphenyl, aflatoxins, benzene, benzidine, benzo[a]pyrene, coke production, formaldehyde, occupational exposure as a painter, sulfur mustard, and vinyl chloride). Aberrant DNA methylation was most commonly studied, followed by altered expression of non-coding RNAs and histone changes (totaling 85, 59 and 25 studies, respectively). For 3 carcinogens (aflatoxins, benzene and benzo[a]pyrene), 10 or more studies reported epigenetic effects. However, epigenetic studies were sparse for the remaining 9 carcinogens; for 4 agents, only 1 or 2 published reports were identified. While further research is needed to better identify carcinogenesis-associated epigenetic perturbations for many potential carcinogens, published reports on specific epigenetic endpoints can be systematically identified and increasingly incorporated in cancer hazard assessments. PMID:27234561

Investigation on the toxic potential of Tribulus terrestris in vitro.

PubMed

Abudayyak, M; Jannuzzi, A T; Özhan, G; Alpertunga, B

2015-04-01

Tribulus terrestris L. (Zygophyllaceae) has been commonly used to energize, vitalize, and improve sexual function and physical performance in men. This study investigates the potential cytotoxic and genotoxic, and endocrine disrupting activities of T. terrestris in vitro. The whole T. terrestris plant was extracted with water, methanol, and chloroform. The genotoxic potential of T. terrestris extracts at 3-2400 µg/mL was assessed by Comet assay in a rat kidney cell line (NRK-52E) and by Ames assay in Salmonella typhimurium TA98 and TA100 strains. Endocrine disrupting effects of the extracts at concentrations of 0.22-25 000 µg/mL were assessed by YES/YAS assay in Saccharomyces cerevisiae. Cytotoxic activity of the extracts was determined by the MTT test in NRK-52E cells. The different exposure times were used for four tests (3-48 h). The methanol extract of T. terrestris IC50 value was 160 µg/mL. The other extracts did not show cytotoxic effects. In the Comet and Ames genotoxicity assays, none of the extracts possessed genotoxic activities at concentrations of 0-2400 µg/mL. Only the water extract of T. terrestris induced frame shift mutations after metabolic activation. The water extract also showed estrogenic activity by YES/YAS assay in S. cerevisiae at concentrations ≥27 µg/mL (≥2.6-fold), while the other T. terrestris extracts had anti-estrogenic properties. Tribulus terrestris had estrogenic and genotoxic activities. The study was useful in determining its toxicological effects and the precautions regarding consumption.

Genotoxic potential of diesel exhaust particles from the combustion of first- and second-generation biodiesel fuels-the FuelHealth project.

PubMed

Kowalska, Magdalena; Wegierek-Ciuk, Aneta; Brzoska, Kamil; Wojewodzka, Maria; Meczynska-Wielgosz, Sylwia; Gromadzka-Ostrowska, Joanna; Mruk, Remigiusz; Øvrevik, Johan; Kruszewski, Marcin; Lankoff, Anna

2017-11-01

Epidemiological data indicate that exposure to diesel exhaust particles (DEPs) from traffic emissions is associated with higher risk of morbidity and mortality related to cardiovascular and pulmonary diseases, accelerated progression of atherosclerotic plaques, and possible lung cancer. While the impact of DEPs from combustion of fossil diesel fuel on human health has been extensively studied, current knowledge of DEPs from combustion of biofuels provides limited and inconsistent information about its mutagenicity and genotoxicity, as well as possible adverse health risks. The objective of the present work was to compare the genotoxicity of DEPs from combustion of two first-generation fuels, 7% fatty acid methyl esters (FAME) (B7) and 20% FAME (B20), and a second-generation 20% FAME/hydrotreated vegetable oil (SHB: synthetic hydrocarbon biofuel) fuel. Our results revealed that particulate engine emissions from each type of biodiesel fuel induced genotoxic effects in BEAS-2B and A549 cells, manifested as the increased levels of single-strand breaks, the increased frequencies of micronuclei, or the deregulated expression of genes involved in DNA damage signaling pathways. We also found that none of the tested DEPs showed the induction of oxidative DNA damage and the gamma-H2AX-detectable double-strand breaks. The most pronounced differences concerning the tested particles were observed for the induction of single-strand breaks, with the greatest genotoxicity being associated with the B7-derived DEPs. The differences in other effects between DEPs from the different biodiesel blend percentage and biodiesel feedstock were also observed, but the magnitude of these variations was limited.

Genotoxicity and growth inhibition effects of aniline on wheat.

PubMed

Tao, Nan; Liu, Guanyi; Bai, Lu; Tang, Lu; Guo, Changhong

2017-02-01

Aniline is a synthetic compound widely used in industrial and pesticide production, which can lead to environmental pollution. Its high concentration in rivers and lakes is hazardous to aquatic species. Although the mechanism of aniline toxicity has been studied extensively in animals and algae, little is known about its genotoxicity in plants. In this study, we investigated the genotoxicity effects of aniline on wheat root tip cells. The mitotic index of wheat root tip cells decreased when the aniline test concentration was higher than 10 mg L -1 . The frequency of micronucleus and chromosomal aberrations increased at aniline concentrations ranging between 5 and 100 mg L -1 , and reached 23.3‰ ± 0.3‰ and 8.9‰ ± 0.68‰, respectively, at an aniline concentration of 100 mg L -1 . These values were sevenfold higher than those in the control group. The wheat seedlings showed various growth toxicity effects under different concentrations of aniline. The shoot height, root length, fresh weight, and dry weight of wheat seedlings decreased at aniline test concentrations ranging between 25 and 200 mg L -1 . At 200 mg L -1 aniline, the dry weight was only one-third that of the control group. Overall, the findings of this study provide evidence that aniline is a serious environmental pollutant causing deleterious genotoxic effects on wheat root tip cells and growth toxic effects on wheat seedlings. However, understanding the mechanisms that underlie aniline genotoxicity in plants needs further study. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lycopene, resveratrol, vitamin C and FeSO4 increase damage produced by pro-oxidant carcinogen 4-nitroquinoline-1-oxide in Drosophila melanogaster: Xenobiotic metabolism implications.

PubMed

Dueñas-García, I E; Heres-Pulido, M E; Arellano-Llamas, M R; De la Cruz-Núñez, J; Cisneros-Carrillo, V; Palacios-López, C S; Acosta-Anaya, L; Santos-Cruz, L F; Castañeda-Partida, L; Durán-Díaz, A

2017-05-01

4-nitroquinoline-1-oxide (4-NQO) is a pro-oxidant carcinogen bioactivated by xenobiotic metabolism (XM). We investigated if antioxidants lycopene [0.45, 0.9, 1.8 μM], resveratrol [11, 43, 172 μM], and vitamin C [5.6 mM] added or not with FeSO 4 [0.06 mM], modulate the genotoxicity of 4-NQO [2 mM] with the Drosophila wing spot test standard (ST) and high bioactivation (HB) crosses, with inducible and high levels of cytochromes P450, respectively. The genotoxicity of 4-NQO was higher when dissolved in an ethanol - acetone mixture. The antioxidants did not protect against 4-NQO in any of both crosses. In the ST cross, resveratrol [11 μM], vitamin C and FeSO 4 resulted in genotoxicity; the three antioxidants and FeSO 4 increased the damage of 4-NQO. In the HB cross, none of the antioxidants, neither FeSO 4 , were genotoxic. Only resveratrol [172 μM] + 4-NQO increased the genotoxic activity in both crosses. We concluded that the effects of the antioxidants, FeSO 4 and the modulation of 4-NQO were the result of the difference of Cyp450s levels, between the ST and HB crosses. We propose that the basal levels of the XM's enzymes in the ST cross interacted with a putative pro-oxidant activity of the compounds added to the pro-oxidant effects of 4-NQO. Copyright © 2017. Published by Elsevier Ltd.

Structure-mutagenicity relationship of kaurenoic acid from Xylopia sericeae (Annonaceae).

PubMed

Cavalcanti, B C; Ferreira, J R O; Moura, D J; Rosa, R M; Furtado, G V; Burbano, R R; Silveira, E R; Lima, M A S; Camara, C A G; Saffi, J; Henriques, J A P; Rao, V S N; Costa-Lotufo, L V; Moraes, M O; Pessoa, C

2010-08-30

Kaurane diterpenes are considered important compounds in the development of new highly effective anticancer chemotherapeutic agents. Genotoxic effects of anticancer drugs in non-tumour cells are of special significance due to the possibility that they induce secondary tumours in cancer patients. In this context, we evaluated the genotoxic and mutagenic potential of the natural diterpenoid kaurenoic acid (KA), i.e. (-)-kaur-16-en-19-oic acid, isolated from Xylopia sericeae St. Hill, using several standard in vitro and in vivo protocols (comet, chromosomal aberration, micronucleus and Saccharomyces cerevisiae assays). Also, an analysis of structure-activity relationships was performed with two natural diterpenoid compounds, 14-hydroxy-kaurane (1) and xylopic acid (2), isolated from X. sericeae, and three semi-synthetic derivatives of KA (3-5). In addition, considering the importance of the exocyclic double bond (C16) moiety as an active pharmacophore of KA cytotoxicity, we also evaluated the hydrogenated derivative of KA, (-)-kauran-19-oic acid (KAH), to determine the role of the exocyclic bond (C16) in the genotoxic activity of KA. In summary, the present study shows that KA is genotoxic and mutagenic in human peripheral blood leukocytes (PBLs), yeast (S. cerevisiae) and mice (bone marrow, liver and kidney) probably due to the generation of DNA double-strand breaks (DSB) and/or inhibition of topoisomerase I. Unlike KA, compounds 1-5 and KAH are completely devoid of genotoxic and mutagenic effects under the experimental conditions used in this study, suggesting that the exocyclic double bond (C16) moiety may be the active pharmacophore of the genetic toxicity of KA. 2010 Elsevier B.V. All rights reserved.

Genotoxicity and toxicity assay of water sampled from a radium production industry storage cell territory by means of Allium-test.

PubMed

Evseeva, Tatiana I; Geras'kin, Stanislav A; Shuktomova, Ida I

2003-01-01

Water from natural reservoirs located near the radium production industry storage cell were analyzed using the anaphase-telophase chromosome aberration assay that was carried out on Allium schoenoprasum L. meristematic root tip cells. (262)Ra, (228)U, (232)Th, (210)Pb and (210)Po concentrations in all samples were found not to exceed the radioactivity concentration guides. The concentrations of 10 heavy metal ions were measured in water samples, but only Zn and Mn levels exceeded the maximum permissible concentration for the natural reservoirs. All water samples caused a significant increase of the chromosome aberration frequency as compared to control. The chromosome aberration spectrum analysis shows that the genotoxic effect was a result of chemical toxicity mainly. Two samples from the brook springhead were found to be toxic. The regression analysis results show that the mitotic index increased in parallel to Zn ion levels, and decreased with higher (238)U concentrations. The water samples genotoxicity positively correlated with the Zn concentration. The present work demonstrates that in order to achieve pollutant screening, it is not sufficient to determine the pollutants concentration only. Adequate conclusions on the risk due to environment contamination need to be based on the additional simultaneous use of toxicity and genotoxicity tests. When bioassays indicate some genotoxic and toxic effects, the determination of the chemical composition of the samples is then required. A combination of these two methods allows the identification of the elements that require constant biological monitoring. In the study reported here, those elements are Zn and (238)U.

In vivo genotoxicity assessment in rats exposed to Prestige-like oil by inhalation.

PubMed

Valdiglesias, Vanessa; Kiliç, Gözde; Costa, Carla; Amor-Carro, Óscar; Mariñas-Pardo, Luis; Ramos-Barbón, David; Méndez, Josefina; Pásaro, Eduardo; Laffon, Blanca

2012-01-01

One of the largest oil spill disasters in recent times was the accident of the oil tanker Prestige in front of the Galician coast in 2002. Thousands of people participated in the cleanup of the contaminated areas, being exposed to a complex mixture of toxic substances. Acute and prolonged respiratory symptoms and genotoxic effects were reported, although environmental exposure measurements were restricted to current determinations, such that attribution of effects observed to oil exposure is difficult to establish. The aim of this study was to analyze peripheral blood leukocytes (PBL) harvested from a rat model of subchronic exposure to a fuel oil with similar characteristics to that spilled by the Prestige tanker, in order to determine potential genotoxic effects under strictly controlled, in vivo exposure. Wistar Han and Brown Norway rats were exposed to the oil for 3 wk, and micronucleus test (MN) and comet assay, standard and modified with 8-oxoguanine DNA glycosylase (OGG1) enzyme, were employed to assess genotoxicity 72 h and 15 d after the last exposure. In addition, the potential effects of oil exposure on DNA repair capacity were determined by means of mutagen sensitivity assay. Results obtained from this study showed that inhalation oil exposure induced DNA damage in both Brown Norway and Wistar Han rats, especially in those animals evaluated 15 d after exposure. Although alterations in the DNA repair responses were noted, the sensitivity to oil substances varied depending on rat strain. Data support previous positive genotoxicity results reported in humans exposed to Prestige oil during cleanup tasks.

Antibiotics and UV Radiation Induce Competence for Natural Transformation in Legionella pneumophila▿ †

PubMed Central

Charpentier, Xavier; Kay, Elisabeth; Schneider, Dominique; Shuman, Howard A.

2011-01-01

Natural transformation by competence is a major mechanism of horizontal gene transfer in bacteria. Competence is defined as the genetically programmed physiological state that enables bacteria to actively take up DNA from the environment. The conditions that signal competence development are multiple and elusive, complicating the understanding of its evolutionary significance. We used expression of the competence gene comEA as a reporter of competence development and screened several hundred molecules for their ability to induce competence in the freshwater living pathogen Legionella pneumophila. We found that comEA expression is induced by chronic exposure to genotoxic molecules such as mitomycin C and antibiotics of the fluoroquinolone family. These results indicated that, in L. pneumophila, competence may be a response to genotoxic stress. Sunlight-emitted UV light represents a major source of genotoxic stress in the environment and we found that exposure to UV radiation effectively induces competence development. For the first time, we show that genetic exchanges by natural transformation occur within an UV-stressed population. Genotoxic stress induces the RecA-dependent SOS response in many bacteria. However, genetic and phenotypic evidence suggest that L. pneumophila lacks a prototypic SOS response and competence development in response to genotoxic stress is RecA independent. Our results strengthen the hypothesis that competence may have evolved as a DNA damage response in SOS-deficient bacteria. This parasexual response to DNA damage may have enabled L. pneumophila to acquire and propagate foreign genes, contributing to the emergence of this human pathogen. PMID:21169481

In vitro toxicological assessment of iron oxide, aluminium oxide and copper nanoparticles in prokaryotic and eukaryotic cell types.

PubMed

Sadiq, Rakhshinda; Khan, Qaiser Mahmood; Mobeen, Ameena; Hashmat, Amer Jamal

2015-04-01

Metallic nanoparticles (NPs) have a variety of applications in different industries including pharmaceutical industry where these NPs are used mainly for image analysis and drug delivery. The increasing interest in nanotechnology is largely associated with undefined risks to the human health and to the environment. Therefore, in the present study cytotoxic and genotoxic effects of iron oxide, aluminium oxide and copper nanoparticles were evaluated using most commonly used assays i.e. Ames assay, in vitro cytotoxicity assay, micronucleus assay and comet assay. Cytotoxicity to bacterial cells was assessed in terms of colony forming units by using Escherichia coli (gram negative) and Bacillus subtilis (gram positive). Ames assay was carried out using two bacterial strains of Salmonella typhimurium TA98 and TA100. Genotoxicity of these NPs was evaluated following exposure to monkey kidney cell line, CHS-20. No cytotoxic and genotoxic effects were observed for iron oxide, and aluminium oxide NPs. Copper NPs were found mutagenic in TA98 and in TA100 and also found cytotoxic in dose dependent manner. Copper NPs induced significant (p < 0.01) increase in number of binucleated cells with micronuclei (96.6 ± 5.40) at the highest concentration (25 µg/mL). Copper NPs also induced DNA strand breaks at 10 µg/mL and oxidative DNA damage at 5 and 10 µg/mL. We consider these findings very useful in evaluating the genotoxic potential of NPs especially because of their increasing applications in human health and environment with limited knowledge of their toxicity and genotoxicity.

Nucleolar accumulation of APE1 depends on charged lysine residues that undergo acetylation upon genotoxic stress and modulate its BER activity in cells

PubMed Central

Lirussi, Lisa; Antoniali, Giulia; Vascotto, Carlo; D'Ambrosio, Chiara; Poletto, Mattia; Romanello, Milena; Marasco, Daniela; Leone, Marilisa; Quadrifoglio, Franco; Bhakat, Kishor K.; Scaloni, Andrea; Tell, Gianluca

2012-01-01

Apurinic/apyrimidinic endonuclease 1 (APE1) is the main abasic endonuclease in the base excision repair (BER) pathway of DNA lesions caused by oxidation/alkylation in mammalian cells; within nucleoli it interacts with nucleophosmin and rRNA through N-terminal Lys residues, some of which (K27/K31/K32/K35) may undergo acetylation in vivo. Here we study the functional role of these modifications during genotoxic damage and their in vivo relevance. We demonstrate that cells expressing a specific K-to-A multiple mutant are APE1 nucleolar deficient and are more resistant to genotoxic treatment than those expressing the wild type, although they show impaired proliferation. Of interest, we find that genotoxic treatment induces acetylation at these K residues. We also find that the charged status of K27/K31/K32/K35 modulates acetylation at K6/K7 residues that are known to be involved in the coordination of BER activity through a mechanism regulated by the sirtuin 1 deacetylase. Of note, structural studies show that acetylation at K27/K31/K32/K35 may account for local conformational changes on APE1 protein structure. These results highlight the emerging role of acetylation of critical Lys residues in regulating APE1 functions. They also suggest the existence of cross-talk between different Lys residues of APE1 occurring upon genotoxic damage, which may modulate APE1 subnuclear distribution and enzymatic activity in vivo. PMID:22918947

Assessment of status of three water bodies in Serbia based on tissue metal and metalloid concentration (ICP-OES) and genotoxicity (comet assay).

PubMed

Sunjog, Karolina; Kolarević, Stoimir; Kračun-Kolarević, Margareta; Višnjić-Jeftić, Željka; Skorić, Stefan; Gačić, Zoran; Lenhardt, Mirjana; Vasić, Nebojša; Vuković-Gačić, Branka

2016-06-01

Metals and metalloids are natural components of the biosphere, which are not produced per se by human beings, but whose form and distribution can be affected by human activities. Like all substances, they are a contaminant if present in excess compared to background levels and/or in a form that would not normally occur in the environment. Samples of liver, gills, gonads and muscle from European chub, Squalius cephalus, were analyzed for Al, As, B, Ba, Cr, Cu, Fe, Hg, Mn, Mo, Sr and Zn using inductively coupled plasma optical emission spectrometry (ICP-OES) to highlight the importance of tissue selection in monitoring research. The comet assay or single cell gel electrophoresis (SCGE) was selected as an in vivo genotoxicity assay, a rapid and sensitive method for measuring genotoxic effects in blood, liver and gills of the European chub. Microscopic images of comets were scored using Comet IV Computer Software (Perceptive Instruments, UK). The objective of our study was to investigate two reservoirs, Zlatar and Garasi, and one river, Pestan by: (i) determining and comparing metal and metalloid concentrations in sediment, water and tissues of European chub: liver, gills, muscle and gonads (ii) comparing these findings with genotoxicity of water expressed through DNA damage of fish tissues. A clear link between the level of metals in water, sediment and tissues and between metal and genotoxicity levels at examined sites was not found. This suggests that other xenobiotics (possibly the organic compounds), contribute to DNA damage. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genotoxicity and apoptosis in Drosophila melanogaster exposed to benzene, toluene and xylene: Attenuation by quercetin and curcumin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Mahendra P.; Mishra, M.; Sharma, A.

2011-05-15

Monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylene are being extensively used for various industrial and household purposes. Exposure to these hydrocarbons, occupationally or non-occupationally, is harmful to organisms including human. Several studies tested for toxicity of benzene, toluene and xylene, and interestingly, only a few studies looked into the attenuation. We used Drosophila model to test the genotoxic and apoptotic potential of these compounds and subsequently evaluated the efficiency of two phytochemicals, namely, quercetin and curcumin in attenuating test chemical induced toxicity. We exposed third instar larvae of wild type Drosophila melanogaster (Oregon R{sup +}) to 1.0-100.0more » mM benzene, toluene or xylene, individually, for 12, 24 and 48 h and examined their apoptotic and genotoxic potential. We observed significantly (P < 0.001) increased apoptotic markers and genotoxicity in a concentration- and time-dependent manner in organisms exposed to benzene, toluene or xylene. We also observed significantly (P < 0.001) increased cytochrome P450 activity in larvae exposed to test chemicals and this was significantly reduced in the presence of 3',4'-dimethoxyflavone, a known Aryl hydrocarbon receptor (AhR) blocker. Interestingly, we observed a significant reduction in cytochrome P450 activity, GST levels, oxidative stress parameters, genotoxic and apoptotic endpoints when organisms were exposed simultaneously to test chemical along with quercetin or curcumin. The study further suggests the suitability of D. melanogaster as an alternate animal model for toxicological studies involving benzene, toluene and xylene and its potential in studying the protective role(s) of phytochemicals.« less

IWGT report on quantitative approaches to genotoxicity risk assessment II. Use of point-of-departure (PoD) metrics in defining acceptable exposure limits and assessing human risk

EPA Science Inventory

This is the second of two reports from the International Workshops on Genotoxicity Testing (IWGT) Working Group on Quantitative Approaches to Genetic Toxicology Risk Assessment (the QWG). The first report summarized the discussions and recommendations of the QWG related to the ne...

GENOTOXICITY OF 1,3-DICHLOROPROPANE, 2,2-DICHLOROPROPANE, AND L,1-DICHLOROPROPENE IN SALMONELLA AND E. COLI PROPHAGE-INDUCTION ASSAYS

EPA Science Inventory

Genotoxicity of 1,3-Dichloropropane, 2,2-Dichloropropane, and 1,1-Dichloropropene in
Salmonella and E. coli Prophage-Induction Assays

1,3-Dichloropropane (1,3-DCP), 2,2-dichloropropane (2,2-DCP), and 1,1- dichloropropene (I,I-DCP) have been detected in ground water i...

Environmental genotoxicity evaluation using cytogenetic end points in wild rodents.

PubMed Central

de Souza Bueno, A M; de Bragança Pereira, C A; Rabello-Gay, M N

2000-01-01

We analyzed cytogenetic end points in three populations of two species of wild rodents--Akodon montensis and Oryzomys nigripes--living in an industrial, an agricultural, and a preservation area at the Itajaí Valley, state of Santa Catarina, Brazil. Our purpose was to evaluate the performance of the following end points in the establishment of a genotoxic profile of each area: the polychromatic/normochromatic cell ratio; the mitotic index; the frequency of micronucleated cells both in the bone marrow and peripheral blood; and the frequency of cells with chromosome aberrations in the bone marrow. Preparations were obtained using conventional cytogenetic techniques. The results showed a) the role of the end points used as biomarkers in the early detection of genotoxic agents and in the identification of species and populations at higher risk; b) the difference in sensitivity of the species selected as bioindicators in relation to the cytogenetic end points analyzed; c) the need to use at least two sympatric species to detect the presence of genotoxins in each locality; and d) the need to use several end points when trying to establish a genotoxic profile of an area. PMID:11133397

Differential genotoxicity of diphenyl diselenide (PhSe)2 and diphenyl ditelluride (PhTe)2

PubMed Central

Meinerz, Daiane Francine; Allebrandt, Josiane; Mariano, Douglas O.C.; Waczuk, Emily P.; Soares, Felix Antunes

2014-01-01

Organoselenium compounds have been pointed out as therapeutic agents. In contrast, the potential therapeutic aspects of tellurides have not yet been demonstrated. The present study evaluated the comparative toxicological effects of diphenyl diselenide (PhSe)2 and diphenyl ditelluride (PhTe)2 in mice after in vivo administration. Genotoxicity (as determined by comet assay) and mutagenicicity were used as end-points of toxicity. Subcutaneous administration of high doses of (PhSe)2 or (PhTe)2 (500 µmol/kg) caused distinct genotoxicity in mice. (PhSe)2 significantly decreased the DNA damage index after 48 and 96 h of its injection (p < 0.05). In contrast, (PhTe) caused a significant increase in DNA damage (p < 0.05) after 48 and 96 h of intoxication. (PhSe)2 did not cause mutagenicity but (PhTe)2 increased the micronuclei frequency, indicating its mutagenic potential. The present study demonstrated that acute in vivo exposure to ditelluride caused genotoxicity in mice, which may be associated with pro-oxidant effects of diphenyl ditelluride. In addition, the use of this compound and possibly other related tellurides must be carefully controlled. PMID:24711962

On the relevance of genotoxicity for fish populations I: effects of a model genotoxicant on zebrafish (Danio rerio) in a complete life-cycle test.

PubMed

Diekmann, Markus; Hultsch, Veit; Nagel, Roland

2004-05-28

Genotoxicity may be detected in surface waters by means of various genotoxicity assays. In order to enable an ecotoxicological assessment of the consequences of such genotoxic potential for fish populations, a complete life-cycle test with zebrafish (Danio rerio) and the model genotoxicant 4-nitroquinoline-1-oxide (NQO) was conducted. Zebrafish (f1) were continuously exposed to NQO (i.e. 0.1, 0.3, 1.1, 2.9, and 14.6 microg/l, respectively) from fertilised eggs until sexual maturity. In addition to reproduction studies in the f1-generation, f2-fish were exposed to NQO during the first 6 weeks of development. Up to 2.9 microg/l NQO, fish did not display differences in survival and growth (P < 0.05). A NQO concentration of 14.6 microg/l, however, was lethal. Female fish exposed to all NQO concentrations up to 2.9 microg/l displayed a significant reduction in egg production (P < 0.05). A mathematical simulation revealed that exposure to weak concentrations of NQO is leading to an elevated extinction risk. Copyright 2004 Elsevier B.V.

Seahorse (Hippocampus reidi) as a bioindicator of crude oil exposure.

PubMed

Delunardo, Frederico Augusto Cariello; de Carvalho, Luciano Rodrigues; da Silva, Bruno Ferreira; Galão, Michel; Val, Adalberto Luís; Chippari-Gomes, Adriana R

2015-07-01

This study explored the suitability of the seahorse Hippocampus reidi (Ginsburg, 1933) for assessing biomarkers of genotoxic effects and its use as a sentinel organism to detect the effects of acute exposure to petroleum hydrocarbons. Fish were exposed to three concentrations of crude oil (10, 20 and 30 g/kg) for 96 h, and the activity of phase II biotransformation enzyme glutathione S-transferase (GST) was measured. In addition, we performed genotoxicity assays, such as comet assay, micronucleus (MN) test and nuclear abnormalities (NA) induction, on the erythrocytes of the fish species. Our results revealed that the inhibition of hepatic GST activity in H. reidi was dependent on increasing crude oil concentrations. In contrast, an increase in the damage index (DI) and MN frequency were observed with increased crude oil concentrations. These results indicate that the alkaline comet assay and micronucleus test were suitable and useful in the evaluation of the genotoxicity of crude oil, which could improve determinations of the impact of oil spills on fish populations. In addition, H. reidi is a promising "sentinel organism" to detect the genotoxic impact of petroleum hydrocarbons. Copyright © 2015 Elsevier Inc. All rights reserved.

Genotoxic effects following exposure to air pollution in street vendors from a high-traffic urban area.

PubMed

Domingues, Érica Prado; Silva, Guilherme Gomes; Oliveira, Andrei Barbassa; Mota, Lorrany Marins; Santos, Vanessa Santana Vieira; de Campos, Edimar Olegário; Pereira, Boscolli Barbosa

2018-03-14

Workers in several occupational environments are exposed to pollutants. Street vendors, for example, typically work in a high-traffic urban environment and are exposed to numerous air pollutants, including genotoxic substances emitted by motor vehicles. This study examined the genotoxic effects of exposure to air pollution. We conducted cytological analyses to assess frequencies of micronucleated (MN) and binucleated (BN) cells in a sample of exfoliated oral mucosa cells. We compared street vendors and control subjects in the city of Uberlândia, Minas Gerais, Brazil, and also collected quantitative information on exposure conditions of all test subjects, including concentrations of particulate matter. We found street vendors to exhibit higher frequencies of MN cells compared to the control group. We evaluated the effects of possible confounding variables on MN frequencies, namely the body mass index (BMI), age, as well as smoking and alcohol habits. Multiple linear regression analysis found no significant effects of any of those variables. Our results suggest that continued exposure to air pollution from traffic represents a major source of genotoxicity and raises concerns regarding disease prevention not only in street vendors but also other groups of people working in urban environments.

Genotoxic effect of Pb and Cd on in vitro cultures of Sphagnum palustre: An evaluation by ISSR markers.

PubMed

Sorrentino, Maria Cristina; Capozzi, Fiore; Giordano, Simonetta; Spagnuolo, Valeria

2017-08-01

In the present work, the genotoxic effect of cadmium and lead supplied in a laboratory trial, was investigated for the first time in the moss Sphagnum palustre, by ISSR molecular markers. A total of 169 reproducible bands were obtained with 12 primers, ten of which gave polymorphisms (i.e., appearance/disappearance of bands), indicating a clear genotoxic effect induced by the metals. Both metals induced a decrease of the genome template stability in a dose dependent manner. At concentration >10 -5 Cd also induced a general toxic effect in S. palustre, leading to chlorophyll degradation and moss death. Moreover, we followed the fate of supplied heavy metals into the moss tissue by SEM-EDX to see if they entered the cells. SEM-EDX observations on moss cultures treated with equimolar concentrations of the two metals showed that most Pb precipitated in form of particles on moss surface, while Cd did not aggregate in particles and was not found on moss surface. In light of these findings, we concluded that probably Pb induced a genotoxic effect at lower intracellular concentrations than Cd. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of low density polyethylene membranes for assessment of genotoxicity of PAHs in the Seine River.

PubMed

Vincent-Hubert, Françoise; Uher, Emmanuelle; Di Giorgio, Carole; Michel, Cécile; De Meo, Michel; Gourlay-France, Catherine

2017-03-01

The genotoxicity of river water dissolved contaminants is usually estimated after grab sampling of river water. Water contamination can now be obtained with passive samplers that allow a time-integrated sampling of contaminants. Since it was verified that low density polyethylene membranes (LDPE) accumulate labile hydrophobic compounds, their use was proposed as a passive sampler. This study was designed to test the applicability of passive sampling for combined chemical and genotoxicity measurements. The LDPE extracts were tested with the umu test (TA1535/pSK1002 ± S9) and the Ames assay (TA98, TA100 and YG1041 ± S9). We describe here this new protocol and its application in two field studies on four sites of the Seine River. Field LDPE extracts were negative with the YG1041 and TA100 and weakly positive with the TA98 + S9 and Umu test. Concentrations of labile mutagenic PAHs were higher upstream of Paris than downstream of Paris. Improvement of the method is needed to determine the genotoxicity of low concentrations of labile dissolved organic contaminants.

The anticancer homeopathic composite "Canova Method" is not genotoxic for human lymphocytes in vitro.

PubMed

Seligmann, Igor C; Lima, Patrícia D L; Cardoso, Plínio C S; Khayat, André S; Bahia, Marcelo O; Buchi, Dorli de Freitas; Cabral, Isabel R; Burbano, Rommel R

2003-06-30

The Canova Method (CM) is a homeopathic medicine indicated for the treatment of patients with cancer and for pathologies that involve a depressed immune system, such as AIDS. This product is composed of homeopathic dilutions of Aconitum napellus, Arsenicum album (arsenic trioxide), Bryonia alba, Lachesis muta venom and Thuya occidentalis. It stimulates the immune system by activating macrophages. Activated macrophages stimulate the lymphocytes so that they increase their cytotoxic action in response to tumoral growth or infection. Given that the CM stimulates and accelerates the activity of macrophages and lymphocytes, we evaluated genotoxic effects induced in human lymphocytes treated with this homeopathic medication in vitro. Structural and numerical chromosomal aberrations were scored for the assessment of induced genotoxic effects, while the variation in mitotic index was considered as a monitor for induced cellular toxicity. The lymphocytes were cultivated for 24, 48 or 72 h in the following final concentrations of the medicinal composite CM: 4, 8 and 12%. Treatments with the CM did not affect mitotic indexes, nor did they provoke chromosomal aberrations, when compared with untreated controls. There was no cytotoxicity or genotoxicity at the chromosomal level.

Genotoxic effects of structurally related beta-carboline alkaloids.

PubMed

Picada, J N; da Silva, K V; Erdtmann, B; Henriques, A T; Henriques, J A

1997-10-06

beta-Carboline alkaloids, found in medicinal plants, tobacco smoke and well-cooked foods, have shown a variety of actions in biological systems related to their interaction with DNA. Therefore, these alkaloids can be considered potentially mutagenic. In this work, the genotoxic, mutagenic, and cytotoxic activities of three aromatic beta-carboline alkaloids (harman, harmine, and harmol) and two dihydro-beta-carboline alkaloids (harmaline and harmalol) were evaluated by means of the Salmonella/microsome assay (Salmonella typhimurium TA98, TA97, TA100, and TA102) and SOS chromotest (Escherichia coli PQ37) with and without metabolic activation. Moreover, harman and harmine were analyzed by the micronucleus assay in vivo. It was shown that genotoxicity was inhibited by the addition of S9 mix for aromatic beta-carbolines harman and harmol in TA97. However, harmine showed signs of mutagenicity only in the presence of S9 mix in TA98 and TA97 frameshift strains. In the SOS chromotest, only harman induced SOS functions in the absence of S9 mix. Dihydro-beta-carbolines were not genotoxic in any of the microorganisms used. The negative responses obtained in the micronucleus assay indicated that harman and harmine were not able to induce chromosomal mutations.

Genotoxic Potential and Physicochemical Parameters of Sinos River, Southern Brazil

PubMed Central

Scalon, Madalena C. S.; Rechenmacher, Ciliana; Siebel, Anna Maria; Kayser, Michele L.; Rodrigues, Manoela T.; Maluf, Sharbel W.; Rodrigues, Marco Antonio S.

2013-01-01

The present study aimed to evaluate the physicochemical parameters and the genotoxic potential of water samples collected in the upper, middle, and lower courses of the Sinos River, southern Brazil. The comet assay was performed in the peripheral blood of fish Hyphessobrycon luetkenii exposed under laboratory conditions to water samples collected in summer and winter in three sampling sites of Sinos River. Water quality analysis demonstrated values above those described in Brazilian legislation in Parobé and Sapucaia do Sul sites, located in the middle and in the lower courses of the Sinos River, respectively. The Caraá site, located in the upper river reach, presented all the physicochemical parameters in accordance with the allowed limits in both sampling periods. Comet assay in fish revealed genotoxicity in water samples collected in the middle course site in summer and in the three sites in winter when compared to control group. Thus, the physicochemical parameters indicated that the water quality of the upper course complies with the limits set by the national guidelines, and the ecotoxicological assessment, however, indicated the presence of genotoxic agents. The present study highlights the importance of combining water physicochemical analysis and bioassays to river monitoring. PMID:24285934

Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

PubMed

Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

2014-10-21

Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

In vitro evaluation of genotoxic effects under magnetic resonant coupling wireless power transfer.

PubMed

Mizuno, Kohei; Shinohara, Naoki; Miyakoshi, Junji

2015-04-07

Wireless power transfer (WPT) technology using the resonant coupling phenomenon has been widely studied, but there are very few studies concerning the possible relationship between WPT exposure and human health. In this study, we investigated whether exposure to magnetic resonant coupling WPT has genotoxic effects on WI38VA13 subcloned 2RA human fibroblast cells. WPT exposure was performed using a helical coil-based exposure system designed to transfer power with 85.4% efficiency at a 12.5-MHz resonant frequency. The magnetic field at the positions of the cell culture dishes is approximately twice the reference level for occupational exposure as stated in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. The specific absorption rate at the positions of the cell culture dishes matches the respective reference levels stated in the ICNIRP guidelines. For assessment of genotoxicity, we studied cell growth, cell cycle distribution, DNA strand breaks using the comet assay, micronucleus formation, and hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutation, and did not detect any significant effects between the WPT-exposed cells and control cells. Our results suggest that WPT exposure under the conditions of the ICNIRP guidelines does not cause detectable cellular genotoxicity.

Cyto- and genotoxic profile of groundwater used as drinking water supply before and after disinfection.

PubMed

Pellacani, C; Cassoni, F; Bocchi, C; Martino, A; Pinto, G; Fontana, F; Furlini, M; Buschini, A

2016-12-01

The assessment of the toxicological properties of raw groundwater may be useful to predict the type and quality of tap water. Contaminants in groundwater are known to be able to affect the disinfection process, resulting in the formation of substances that are cytotoxic and/or genotoxic. Though the European directive (98/83/EC, which establishes maximum levels for contaminants in raw water (RW)) provides threshold levels for acute exposure to toxic compounds, the law does not take into account chronic exposure at low doses of pollutants present in complex mixture. The purpose of this study was to evaluate the cyto- and genotoxic load in the groundwater of two water treatment plants in Northern Italy. Water samples induced cytotoxic effects, mainly observed when human cells were treated with RW. Moreover, results indicated that the disinfection process reduced cell toxicity, independent of the biocidal used. The induction of genotoxic effects was found, in particular, when the micronucleus assay was carried out on raw groundwater. These results suggest that it is important to include bio-toxicological assays as additional parameters in water quality monitoring programs, as their use would allow the evaluation of the potential risk of groundwater for humans.

Assessing the genotoxic effects of two lipid peroxidation products (4-oxo-2-nonenal and 4-hydroxy-hexenal) in haemocytes and midgut cells of Drosophila melanogaster larvae.

PubMed

Demir, Eşref; Marcos, Ricard

2017-07-01

Lipid peroxidation products can induce tissue damage and are implicated in diverse pathological conditions, including aging, atherosclerosis, brain disorders, cancer, lung and various liver disorders. Since in vivo studies produce relevant information, we have selected Drosophila melanogaster as a suitable in vivo model to characterise the potential risks associated to two lipid peroxidation products namely 4-oxo-2-nonenal (4-ONE) and 4-hydroxy-hexenal (4-HHE). Toxicity, intracellular reactive oxygen species production, and genotoxicity were the end-points evaluated. Haemocytes and midgut cells were the evaluated targets. Results showed that both compounds penetrate the intestine of the larvae, affecting midgut cells, and reaching haemocytes. Significant genotoxic effects, as determined by the comet assay, were observed in both selected cell targets in a concentration/time dependent manner. This study highlights the importance of D. melanogaster as a model organism in the study of the different biological effects caused by lipid peroxidation products entering via ingestion. This is the first study reporting genotoxicity data in haemocytes and midgut cells of D. melanogaster larvae for the two selected compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

Genotoxicity evaluation of So-ochim-tang-gamibang (SOCG), a herbal medicine.

PubMed

Lee, Mi Young; Park, Yang-Chun; Jin, Mirim; Kim, Eunseok; Choi, Jeong June; Jung, In Chul

2018-02-02

So-ochim-tang-gamibang (SOCG) is a traditional Korean medicine frequently used for depression in the clinical field. In this study, we evaluated the potential genotoxicity of SOCG using three standard batteries of tests as part of a safety evaluation. SOCG was evaluated for potential genotoxic effects using the standard three tests recommended by the Ministry of Food and Drug Safety (MFDS) of Korea. These tests were the bacterial reverse mutation test (Ames test), in vitro mammalian chromosomal aberration test using Chinese hamster lung cells, and in vivo micronucleus test using ICR mice. The Ames test with Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537 and the Escherichia coli strain WP2uvrA(pKM101) showed that SOCG did not induce gene mutations at any dose level in all of the strains. SOCG did not induce any chromosomal aberrations in the in vitro chromosomal aberration test (for both the 6 and 24 h test) and the in vivo micronucleus test. Based on the results of these tests, it was concluded that SOCG does not exhibit any genotoxic risk under the experimental conditions of this study.

3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX): toxicological properties and risk assessment in drinking water.

PubMed

Hirose, A; Nishikawa, A; Kinae, N; Hasegawa, R

1999-01-01

MX (3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone), one of the byproducts formed during the chlorine disinfection process of drinking water, shows strong mutagenic activity for Salmonella strains in the Ames test. In several countries, the contribution of MX to the total mutagenicity of drinking water is estimated to range from 7% to 67%. To assess the risk of MX for human health, we summarized the toxicological properties of MX and estimated the tolerable daily intake (TDI) or tolerable concentration in drinking water. MX is genotoxic in cultured mammalian cells and causes in vivo DNA damage in several tissues. MX is carcinogenic for rodents in addition to possessing skin and gastric promotion activities. From these toxicological profiles of MX, we estimated the virtual safety dose (VSD) for genotoxic action as 5 ng/kg/d and the TDI for non-genotoxic action of MX as 40 ng/kg/d. We assumed a tolerable MX concentration of 150 ng/L in drinking water. Because of the uncertainty about human genotoxicity, however, and the lack of information on reproductive or developmental toxicity, the estimated tolerable dose level may be provisional.

Evaluation of Hypoglycemic and Genotoxic Effect of Polyphenolic Bark Extract from Quercus sideroxyla

PubMed Central

Soto-García, Marcela; Rosales-Castro, Martha; Escalona-Cardoso, Gerardo N.

2016-01-01

Quercus sideroxyla is a wood species whose bark has phenolic compound and should be considered to be bioactive; the hypoglycemic and genotoxic properties of Q. sideroxyla bark were evaluated in this study. Total phenolic compound was determined in crude extract (CE) and organic extract (OE). The OE has the highest amount of phenols (724.1 ± 12.0 GAE/g). Besides, both CE and OE demonstrated effect over the inhibition of α-amylase in vitro. Hypoglycemic activity was assessed by glucose tolerance curve and the area under curve (UAC); OE showed the highest hypoglycemic activity. In addition, diabetes was induced by streptozotocin (65 mg/kg) and the extracts (50 mg/kg) were administered for 10 days; OE showed hypoglycemic effect compared with diabetic control and decreased hepatic lipid peroxidation. Acute toxicity and genotoxicity were evaluated in CE; results of acute toxicity did not show any mortality. Besides, the comet assay showed that CE at a dose of 100 mg/kg did not show any genotoxic effect when evaluated at 24 h, whereas it induced slight damage at 200 mg/kg, with the formation of type 1 comets. PMID:27867402

Lack of in vivo embryotoxic and genotoxic activities of orally administered stem bark aqueous extract of Mangifera indica L. (Vimang).

PubMed

González, J E; Rodríguez, M D; Rodeiro, I; Morffi, J; Guerra, E; Leal, F; García, H; Goicochea, E; Guerrero, S; Garrido, G; Delgado, R; Nuñez-Selles, A J

2007-12-01

Mango (Mangifera indica L.) stem bark aqueous extract (MSBE) is a new natural product with antioxidant, anti-inflammatory and immunomodulatory effects known by the brand name of its formulations as Vimang. Previously, the oral toxicity studies of the extract showed a low toxicity potential up to 2000 mg/kg. This work reports the results about teratogenic and genotoxicologic studies of MSBE. For embryotoxicity study, MSBE (20, 200, or 2000 mg/kg/day) was given to Sprague-Dawley rats by gavage on days 6-15 of gestation. For genotoxicity, MSBE was administered three times during 48 h to NMRI mice. Cyclophosphamide (50 mg/kg) was used as a positive control. No maternal or developmental toxicities were observed when the rats were killed on day 20th. The maternal body-weight gain was not affected. No dose-related effects were observed in implantations, fetal viability or external fetal development. Skeletal and visceral development was similar among fetuses from all groups. No genotoxicity was observed in bone marrow erythrocytes and liver cells after administration. MSBE appears to be neither embryotoxic nor genotoxic as measured by bone marrow cytogenetics in rodents.

Assessing genotoxicity of diuron on Drosophila melanogaster by the wing-spot test and the wing imaginal disk comet assay.

PubMed

Peraza-Vega, Ricardo I; Castañeda-Sortibrán, América N; Valverde, Mahara; Rojas, Emilio; Rodríguez-Arnaiz, Rosario

2017-05-01

The aim of this study was to evaluate the genotoxicity of the herbicide diuron in the wing-spot test and a novel wing imaginal disk comet assay in Drosophila melanogaster. The wing-spot test was performed with standard (ST) and high-bioactivation (HB) crosses after providing chronic 48 h treatment to third instar larvae. A positive dose-response effect was observed in both crosses, but statistically reduced spot frequencies were registered for the HB cross compared with the ST. This latter finding suggests that metabolism differences play an important role in the genotoxic effect of diuron. To verify diuron's ability to produce DNA damage, a wing imaginal disk comet assay was performed after providing 24 h diuron treatment to ST and HB third instar larvae. DNA damage induced by the herbicide had a significantly positive dose-response effect even at very low concentrations in both strains. However, as noted for the wing-spot test, a significant difference between strains was not observed that could be related to the duration of exposure between both assays. A positive correlation between the comet assay and the wing-spot test was found with regard to diuron genotoxicity.