Genotoxic Compounds Research Articles

High molecular weight polycyclic aromatic hydrocarbon (HMW-PAH) isomers: unveiling distinct toxic effects from cytotoxicity to oxidative stress-induced DNA damage.

Polycyclic aromatic hydrocarbons (PAHs) represent one of the most extensive classes of known carcinogenic and genotoxic compounds widely distributed across the globe. Particularly relevant to ecotoxicological studies is the possible presence of PAHs with molecular weight (MW) 302Da. Since the toxicity of 302Da PAHs differs significantly from isomer to isomer, understanding their relative toxicity is essential for assessing their potential risks to human health. This study investigates the toxic effects of micromolar concentrations of four HMW-PAHs isomers of MW = 302Da, namely dibenzo(b,l)fluoranthene (DB(b,l)F), dibenzo(a,j)fluoranthene (DB(a,j)F), dibenzo(a,l)fluoranthene (DB(a,l)F) and naphtho(1-2j)fluoranthene (N(1-2j)F), upon exposure and metabolic activation in HepG2 cells. Appropriate assays were selected to investigate their potential to disrupt cellular viability and to induce cytotoxicity, apoptosis/necrosis, genotoxicity, and oxidative stress with DNA damage. After 48h of exposure time, DB(a,l)F was the only isomer to reduce cellular viability in a concentration-dependent manner. In all cases, apoptosis was the main mechanism of HepG2 cell death, which could be induced by the significant DNA damage and an increase in 8-hydroxy-2'-deoxyguanosine (8-OHdG) adduct level formation. The highest concentrations of DB(a,l)F tested exhibited the greatest potential to induce HepG2 DNA damage and 8-OHdG formation. Altogether, these facts demonstrate that the distinct arrangements of the atoms in HMW-PAHs isomers can impact on their toxic potential and that DB(a,l)F was the most toxic isomer evaluated in this study. These results shed light on the importance to thoroughly characterize MW302 PAHs to substantiate their human and environmental risk assessments.

A study on the impact of industrial-scale refining on olive oil and olive pomace oil contamination with mineral oils

Mineral oil hydrocarbons (MOH), including saturated (MOSH) and aromatic (MOAH) hydrocarbons, are contaminants of petrogenic origin. On-line high-performance liquid chromatography (HPLC) – gas chromatography (GC) – flame ionization detector (FID) was used for determining MOH in olive oils (OOs) and olive pomace oils (OPOs) at different stages of the refining process and in samples from the Italian market. Deodorization reduced contamination by about 30 %, resulting in a significant reduction of endogenous n-alkanes generally up to n-C31. Comprehensive GC coupled to quadrupole time-of-flight (QTOF) mass spectrometry (MS) allowed investigating the effect of bleaching on a sample of OPO naturally contaminated with alkylated PAHs, demonstrating the removal capacity of this refining step on potentially carcinogenic genotoxic compounds derived from MOH contamination. OOs from the market contained on average 33.1 mg/kg of MOSH n-C10–50 and 3.3 mg/kg of MOAH, while OPOs contained on average 160.7 and 36.1 mg/kg of MOSH and MOAH, respectively.

Screening of municipal effluents with the peroxidase toxicity assay

The peroxidase (Per) reaction is a quick and inexpensive biosensor for the screening of environmental contaminants and wastewaters. The purpose of this study was to screen various municipal wastewaters before and after 7 different types of treatment processes using this sensor to identify potential sites under stress by urban pollution. The following wastewater samples before (influent) and after the commonly applied treatments (effluent) were tested using the Per activity test: advanced biofiltration, biofiltration, aerated lagoons, secondary aeration sludge, trickling filter, secondary membrane filtration, and primary. The influents and effluents were collected for 3 days and concentrated to 500 X on a reverse-phase (C18) extraction cartridge. The ethanol extracts were examined for dissolved organic carbon, plastic-like materials, polyaromatic hydrocarbons and polystyrene nanoplastics. The samples were then tested using the Per reaction alone and in the presence of DNA to detect DNA binding agents. The results show that population size tended to increase Per activity and 60% of the effluents decreased Per activity leading to H2O2 persistence and toxicity. More advanced treatments (biofiltration, membrane biofiltration, secondary aeration) produced stronger changes from the corresponding untreated influents corroborating their performance in reducing toxicity. The addition of DNA during the Per reaction revealed that population size had no influence and that 60% of treated effluents restored Per activity suggesting release of genotoxic compounds in the aquatic environment from treated wastewaters. The toxic implications of the continuous release of wastewaters in aquatic ecosystems are discussed in the light of emerging contaminants such as nanoplastics.

Revealing contaminants in China's recycled PET: Enabling safe food contact applications

The lack of data on chemical contamination in recycled polyethylene terephthalate (rPET) in food contact applications, impedes the legalization of rPET in food contact applications in China. This study offers a comprehensive analysis of contaminants in hot-washed rPET flakes, identifying 1011 compounds. While most substances were detected infrequently, some i.e., bis(2-ethylhexyl) phthalate and mineral oil aromatic hydrocarbons stood out for their relatively high average concentrations. Limonene emerged as the most frequently detected flavorants. Rare genotoxic compounds like safrole and diethyl sulfate were detected at low levels, emphasizing the importance of adopting a conservative evaluation approach. Molecular descriptor analysis guided the proposal of four new surrogates, i.e., dimethyl pentanedioate, 2-tridecanone, bis(2-ethylhexyl) terephthalate, and 2,2-dimethoxy-1,2-diphenylethanone, for challenge tests, aiming to better capture the chemical diversity of rPET contaminants. This research unveils the contamination profile of Chinese rPET and suggests adjustments to evaluation protocols, potentially facilitating its high-value applications and minimizing potential harms.

Ultrasensitive mass spectrometric quantitation of apurinic/apyrimidinic sites in genomic DNA of mammalian cell lines exposed to genotoxic reagents

The apurinic/apyrimidinic (AP) site is an important intermediate in the DNA base excision repair (BER) pathway, having the potential of being a biomarker for DNA damage. AP sites could lead to the stalling of polymerases, the misincorporation of bases and DNA strand breaks, which might affect physiological function of cells. However, the abundance of AP sites in genomic DNA is very low (less than 2 AP sites/106 nts), which requires a sensitive and accurate method to meet its detection requirements. Here, we described an ultrasensitive quantification method based on a hydrazine-s-triazine reagent (i-Pr2N) labeling for AP sites combining with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The limit of detection reached an ultralow level (40 amol), realizing the most sensitive MS-based quantification for the AP site. To guarantee the accuracy of the quantitative results, the labeling reaction was carried out directly on DNA strands instead of labeling after DNA enzymatic digestion to reduce artifacts that might be produced during the enzymatic process of DNA strands. And selective detection was realized by MS to avoid introducing the false-positive signals from other aldehyde species, which could also react with i-Pr2N. Genomic DNA samples from different mammalian cell lines were successfully analyzed using this method. There were 0.4–0.8 AP sites per 106 nucleotides, and the values would increase 16.1 and 2.75 times when cells were treated with genotoxic substances methyl methanesulfonate and 5-fluorouracil, respectively. This method has good potential in the analysis of a small number of cell samples and clinical samples, is expected to be useful for evaluating the damage level of DNA bases, the genotoxicity of compounds and the drug resistance of cancer cells, and provides a new tool for cell function research and clinical precise treatment.

Cellular toxicity of calcium propionate in human lymphocyte.

Calcium propionate is the chemical substance added to food in order to prolong the shelf-life of factory made foods by inhibiting the development of bacteria, fungi and other microorganisms. The objective of this study was to investigate the ability of calcium propionate to induce cytotoxic and genotoxic effects in lymphocytes. Oxidative stress induction by calcium propionate was also studied. Four concentrations of calcium propionate (0.5, 1.0, 1.5 and 2.0 mg/ml) were applied in lymphocytes for 24 and 48 h treatment. It studied cytotoxic and genotoxic effects by MTT assay, chromosome culture technique, and micronucleus assay. Oxidative stress induction was studied by superoxide dismutase (SOD) activity assay. The results showed that lymphocyte viability was decreased significantly by calcium propionate at 1.5 and 2.0 mg/ml (p < 0.05). Calcium propionate induced chromosome aberration at 1.0, 1.5 and 2.0 mg/ml and sister chromatid exchange at 1.5 and 2.0 mg/ml (p < 0.05). It induced micronucleus formation at 0.5, 1.0, 1.5 and 2.0 mg/ml (p < 0.05). The calcium propionate concentrations of 0.5 - 1.0 mg/ml and 1.5 - 2.0 mg/ml could reduce SOD activity inhibition (p < 0.05). Calcium propionate induced oxidative stress in lymphocytes. It can be concluded that calcium propionate induces genotoxic risk and oxidative stress in lymphocytes. Based on this study and the positive results, consumers should be made aware that calcium propionate should be considered a genotoxic compound. The awareness of food preservative usage and the educational program must take place frequently for good human health in the community.

Biochemical characterisation and production kinetics of high molecular-weight (HMW) putative antibacterial proteins of insect pathogenic Brevibacillus laterosporus isolates

BackgroundBacterial genomes often encode structures similar to phage capsids (encapsulins) and phage tails which can be induced spontaneously or using genotoxic compounds such as mitomycin C. These high molecular-weight (HMW) putative antibacterial proteins (ABPs) are used against the competitive strains under natural environment. Previously, it was unknown whether these HMW putative ABPs originating from the insect pathogenic Gram-positive, spore-forming bacterium Brevibacillus laterosporus (Bl) isolates (1821L, 1951) are spontaneously induced during the growth and pose a detrimental effect on their own survival. Furthermore, no prior work has been undertaken to determine their biochemical characteristics.ResultsUsing a soft agar overlay method with polyethylene glycol precipitation, a narrow spectrum of bioactivity was found from the precipitated lysate of Bl 1951. Electron micrographs of mitomycin C- induced filtrates showed structures similar to phage capsids and contractile tails. Bioactivity assays of cell free supernatants (CFS) extracted during the growth of Bl 1821L and Bl 1951 suggested spontaneous induction of these HMW putative ABPs with an autocidal activity. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of spontaneously induced putative ABPs showed appearance of ~ 30 kDa and ~ 48 kDa bands of varying intensity across all the time intervals during the bacterial growth except in the initial hours. Statistically, spontaneously induced HMW putative ABPs of Bl 1951 exhibited a significant decrease in the number of viable cells of its producer strain after 18 h of growth in liquid. In addition, a significant change in pH and prominent bioactivity of the CFS of this particular time period was noted. Biochemically, the filtered supernatant derived from either Bl 1821L or Bl 1951 maintained bioactivity over a wide range of pH and temperature.ConclusionThis study reports the spontaneous induction of HMW putative ABPs (bacteriocins) of Bl 1821L and Bl 1951 isolates during the course of growth with potential autocidal activity which is critically important during production as a potential biopesticide. A narrow spectrum of putative antibacterial activity of Bl 1951 precipitate was found. The stability of HMW putative ABPs of Bl 1821L and Bl 1951 over a wide range of pH and temperature can be useful in expanding the potential of this useful bacterium beyond the insecticidal value.

Sensitive Detection of Genotoxic Substances in Complex Food Matrices by Multiparametric High-Content Analysis.

Genotoxic substances widely exist in the environment and the food supply, posing serious health risks due to their potential to induce DNA damage and cancer. Traditional genotoxicity assays, while valuable, are limited by insufficient sensitivity, specificity, and efficiency, particularly when applied to complex food matrices. This study introduces a multiparametric high-content analysis (HCA) for the detection of genotoxic substances in complex food matrices. The developed assay measures three genotoxic biomarkers, including γ-H2AX, p-H3, and RAD51, which enhances the sensitivity and accuracy of genotoxicity screening. Moreover, the assay effectively distinguishes genotoxic compounds with different modes of action, which not only offers a more comprehensive assessment of DNA damage and the cellular response to genotoxic stress but also provides new insights into the exploration of genotoxicity mechanisms. Notably, the five tested food matrices, including coffee, tea, pak choi, spinach, and tomato, were found not to interfere with the detection of these biomarkers under proper dilution ratios, validating the robustness and reliability of the assay for the screening of genotoxic compounds in the food industry. The integration of multiple biomarkers with HCA provides an efficient method for detecting and assessing genotoxic substances in the food supply, with potential applications in toxicology research and food safety.

Effects of Phenols from Olive Vegetation Water on Mutagenicity and Genotoxicity of Stored-Cooked Beef Patties.

This explorative study aimed to assess the mutagenicity and genotoxicity of stored-cooked beef patties formulated with and without phenols (7.00 mg of phenols/80-g patty) extracted from olive vegetation water (OVW), as related to the formation of cholesterol oxidation products (COPs) and heterocyclic amines (HCAs). The patties were packaged in a modified atmosphere, sampled during cold storage (4 °C) for 9 days, and grilled at 200 °C. The genotoxicity was evaluated by the Comet assay. The patty extract was found to be genotoxic on primary peripheral blood mononuclear cells (PBMCs), while no mutagenicity was detected. The addition of OVW phenols significantly decreased the genotoxicity of the patty extract and reduced the total COPs content in stored-cooked patties (4.59 times lower than control); however, it did not affect the content of total HCAs (31.51-36.31 ng/patty) and the revertants' number. Therefore, these results demonstrate that the OVW phenols were able to counteract the formation of genotoxic compounds in stored-cooked beef patties.

Scientific Opinion on additional scientific data related to the safety of preparations of Rheum palmatum L., Rheum officinale Baill. and their hybrids, Rhamnus purshianaDC., Rhamnus frangula L. and Cassia senna L., submitted pursuant to Article 8(4) of Regulation (EC) No 1925/2006.

The Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the safety of plant preparations from the root or rhizome of Rheum palmatum L., Rheum officinale Baill. and their hybrids, from the bark of Rhamnus frangula L. and Rhamnus purshiana DC. and from the leaf or fruit of Cassia senna L., which have been placed under Union scrutiny in Part C of Annex III in accordance with Article 8(4) of Regulation (EC) No 1925/2006. The NDA Panel reviewed the additional scientific data submitted during the period of scrutiny and the public consultation by interested parties. The pertinent scientific data were invitro and invivo genotoxicity studies on the plant preparations under consideration. All the results of the genotoxicity studies on plant preparations were negative. However, the plant preparations that were tested in the submitted studies were not sufficiently characterised with respect to the content of total and individual hydroxyanthracene derivatives (HADs) and components other than HADs. The studies confirmed the presence of ■■■■■, known to be genotoxic invivo, and ■■■■■, shown to be genotoxic invitro. In line with the EFSA Scientific Committee statement on genotoxicity assessment of chemical mixtures, considering the presence of an invivo genotoxic compound, the plant preparations used in these studies have to be considered of concern for genotoxicity. Thus, the safety of preparations containing HADs from the root or rhizome of Rheum palmatum L., Rheum officinale Baill. and their hybrids, from the leaf or fruit of Cassia senna L. and from the bark of Rhamnus frangula L. and Rhamnus purshiana DC. cannot be established based on the submitted studies.

DNA adduct formation in Saccharomyces cerevisiae following exposure to environmental pollutants, as in vivo model for molecular toxicity studies.

DNA adduction in the model yeast Saccharomyces cerevisiae was investigated after exposure to the fungicide penconazole and the reference genotoxic compound benzo(a)pyrene, for validating yeasts as a tool for molecular toxicity studies, particularly of environmental pollution. The effect of the toxicants on the yeast's growth kinetics was determined as an indicator of cytotoxicity. Fermentative cultures of S. cerevisiae were exposed to 2ppm of Penconazole during different phases of growth; while 0.2 and 2ppm of benzo(a)pyrene were applied to the culture medium before inoculation and on exponential cultures. Exponential respiratory cultures were also exposed to 0.2ppm of B(a)P for comparison of both metabolisms. Penconazole induced DNA adducts formation in the exponential phase test; DNA adducts showed a peak of 54.93 adducts/109 nucleotides. Benzo(a)pyrene induced the formation of DNA adducts in all the tests carried out; the highest amount of 46.7 adducts/109 nucleotides was obtained in the fermentative cultures after the exponential phase exposure to 0.2ppm; whereas in the respiratory cultures, 14.6 adducts/109 nucleotides were detected. No cytotoxicity was obtained in any experiment. Our study showed that yeast could be used to analyse DNA adducts as biomarkers of exposure to environmental toxicants.

Assessment of TGx-DDI genes for genotoxicity in a comprehensive panel of chemicals

Background The TGx-DDI biomarker identifies transcripts specifically induced by primary DNA damage. Profiling similarity of TGx-DDI signatures can allow clustering compounds by genotoxic mechanism. This transcriptomics-based approach complements conventional toxicology testing by enhancing mechanistic resolution. Methods Unsupervised hierarchical clustering and t-distributed stochastic neighbor embedding (tSNE) were utilized to assess similarity of publicly-available per- and polyfluoroalkyl substances (PFAS) and ToxCast chemicals based on TGx-DDI modulation. TempO-seq transcriptomic data after highest chemical concentrations were analyzed. Results Clustering discriminated between genotoxic and non-genotoxic compounds while drawing similarity among chemicals with shared mechanisms. PFAS largely clustered distinctly from classical mutagens. However, dynamic range across PFAS types and durations indicated variable potential for DNA damage. tSNE visualization reinforced phenotypic groupings, with genotoxins clustering separately from non-DNA damaging agents. Discussion Unsupervised learning approaches applied to TGx-DDI profiles effectively categorizes chemical genotoxicity potential, aiding elucidation of biological response pathways. This transcriptomics-based strategy gives further insight into the role and effect of individual TGx-DDI biomarker genes and complements existing assays by enhancing mechanistic resolution. Overall, TGx-DDI biomarker profiling holds promise for predictive safety screening.

Abstract LB134: Mutational signatures in colorectal cancer from 11 countries reveal new insights in early-onset colorectal cancer

Abstract Background: Colorectal cancers (CRC) have an important impact on both incidence and mortality worldwide, with varying rates in different parts of the world. Despite an overall decrease in incidence in the past years, an alarming increase in early onset colorectal cancer (CRC in patients under 50 years of age) rates has been observed. As part of the Cancer Research UK Grand Challenge Mutographs project, we aim to better understand the underlying mutagenic causes contributing to the differences in CRC incidence rates through mutational signatures. Methods: We collected epidemiological data and performed whole genome sequencing and mutational signature analysis on 981 CRC tumor samples from 11 countries with varying incidence rates, including intermediate incidence regions (Iran, Colombia, Thailand, and Brazil) and higher incidence regions (Argentina, Russia, Canada, Poland, Czechia, Serbia, and Japan). Results: The average mutational profiles were similar across the countries. Mutational signatures associated with DNA repair deficiencies, including POLE and POLD1 associated signatures (SBS10a/b/c/d and SBS28), MUTYH (SBS36), NTHL1 (SBS30), homologous recombination deficiency (SBS3), and a plethora of microsatellite instability (MSI) signatures, were found in 177 cancers (18% of all samples) and at comparable levels across all countries. Multiple signatures with known etiologies were found in 802 DNA repair proficient colorectal cancers including clock-like (SBS1 and SBS5), reactive oxygen species (SBS18), APOBEC (SBS2 and SBS13), and the microbiome-product colibactin (SBS88) signatures. The colibactin signature SBS88 was observed in 14% of samples overall, being more prevalent in distal and rectum tumors. SBS88 was significantly enriched in younger patients (33% &amp;lt;40y, 23% 40-49y, 20% 50-59y,10% 60-69y, 10% ≥70y; p-value = 0.0001). Tumors from early onset patients also showed higher prevalence of another mutational signature with unknown etiology (19% &amp;lt;40y, 16% 40-49y, 13% 50-59y, 6% 60-69y, 7% ≥70y, p-value = 0.005). Conclusions: These results indicate a potential association between SBS88 with early onset CRC, suggesting that the recent increase in incidence may be at least partially explained by the genotoxic compound colibactin, and associated bacteria. Citation Format: Wellington dos Santos, Marcos Diaz-Gay, Sarah Moody, Sergey Senkin, Behnoush Abedi-Ardekani, Mariya Kazachkova, Stephen Fitzgerald, Saamin Cheema, Valerie Gaborieau, Jingwei Wang, Christine Carreira, Thomas Cattiaux, Priscilia Chopard, Calli Latimer, David Zaridze, Riley Cox, Reza Malekzadeh, Miodrag Ognjanovic, Suleeporn Sangrajrang, Maria P. Curado, Rui M. Reis, Ivana Holcatova, Carlos Vaccaro, Beata Swiatkowska, Jolanta Lissowska, Carolina Wiesner, Tatsuhiro Shibata, Surasak Sangkhathat, Patricia Ashton-Prolla, Laura Humphreys, Sandra Perdomo, Ana C. de Caravalho, Mike Stratton, Paul Brennan, Ludmil Alexandrov. Mutational signatures in colorectal cancer from 11 countries reveal new insights in early-onset colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB134.

Abstract 6231: Multi-omic characterisation of clear cell renal carcinoma reveals endogenous and exogenous processes related to its aetiology

Abstract Endogenous and exogenous exposures are associated with distinctive molecular marks in somatic tissues, including human tumours. Integrative multi-omic approaches could help improving the resolution to detect the molecular marks associated with disease aetiology. Here, we leveraged the overlapping molecular information of clear cell renal cell carcinomas (ccRCC) tumours from Mutographs cohort by integrating DNA methylation, transcriptome, and whole-genome sequencing-based somatic mutation data to explore and gain new insights into exposures linked to ccRCC aetiology. Our novel framework identified important sources of biological variance across ccRCC tumours that were summarized as molecular components. We inferred these molecular ccRCC components into independent datasets to further explore their relationship with molecular and epidemiological features of ccRCC, normal adjacent kidney tissues, and other cancer types. Our results revealed a major ccRCC molecular component correlating with cellular mitotic age-related features, particularly the mitotic epigenetic clock (age-adjusted epiTOC2), clock-like DNA mutational signatures (SBS1/ID1), and telomere attrition. This molecular component was overrepresented in ccRCC tumours in comparison with normal paired kidney tissues, associating with PBRM1 and SETD2 somatic cancer driver mutations, genome stability, tumor stage, grade and ccRCC patient survival, independently to chronological age. Pan-cancer analysis supported the mitotic-age effect, represented by this molecular component, in other cancer types. Another ccRCC component was associated with tobacco usage, the presence of tobacco related DNA mutational and methylation signatures, increased total mutation burden, and sex. This component was also related to the epigenetic regulation of xenobiotic metabolism-related genes (e.g., GSTP1), further suggesting a relationship with genotoxic compounds. We further identified molecular components related to the ccRCC tumour microenvironment and cell proliferation, including one component related to BAP1 cancer driver mutations, pro-inflammatory immune cells, and ccRCC patient survival. In conclusion, our study reports a novel framework to molecular characterize ccRCC tumours using an integrative multi-omic approach, providing additional insights into the molecular footprints of endogenous and exogenous exposures in ccRCC tumours, including molecular components with prognostic value for patients. Citation Format: Ricardo Cortez Cardoso Penha, Alexandra Sexton Oates, Sergey Senkin, Han La Park, Nicolas Alcala, Matthieu Foll, Karl Smith-Byrne, Paul Brennan, James Mckay. Multi-omic characterisation of clear cell renal carcinoma reveals endogenous and exogenous processes related to its aetiology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6231.

XRCC1 Polymorphisms p.Arg194Trp, p.Arg280His, and p.Arg399Gln, Polycyclic Aromatic Hydrocarbons, and Infertility: A Case-Control and In Silico Study.

XRCC1 is involved in repair of single-strand breaks generated by mutagenic exposure. Polymorphisms within XRCC1 affect its ability to efficiently repair DNA damage. Polycyclic aromatic hydrocarbons or PAHs are genotoxic compounds which form bulky DNA adducts that are linked with infertility. Few reports suggest combined role of XRCC1 polymorphisms and PAHs in infertility. Present study investigates association of three XRCC1 polymorphisms (p.Arg194Trp, p.Arg280His, p.Arg399Gln) with male and female infertility in a North-West Indian population using case-control approach. Additionally, in silico approach has been used to predict whether XRCC1 polymorphisms effect interaction of XRCC1 with different PAHs. For case-control study, XRCC1 polymorphisms were screened in peripheral blood samples of age- and gender-matched 201 infertile cases (♂-100, ♀-101) and 201 fertile controls (♂-100, ♀-101) using PCR-RFLP method. For in silico study, AutoDock v4.2.6 was used for molecular docking of B[a]P, BPDE-I, ( ±)-anti-BPDE, DB[a,l]P, 1-N, 2-N, 1-OHP, 2-OHF with XRCC1 and assess effect of XRCC1 polymorphisms on their interaction. In case-control study, statistical analysis showed association of XRCC1 p.Arg280His GA genotype (p = 0.027), A allele (p = 0.019) with reduced risk of male infertility. XRCC1 p.Arg399Gln AA genotype (p = 0.021), A allele (p = 0.014) were associated with reduced risk for female primary infertility. XRCC1 p.Arg194Trp T allele was associated with increased risk for female infertility (p = 0.035). In silico analysis showed XRCC1-PAH interaction with non-significant effect of XRCC1 polymorphisms on predicted binding. Therefore, present study concludes that XRCC1 polymorphism-modified risk for male and female infertility in North-West Indians without significant effect on predicted XRCC1-PAH interactions. This is the first report on XRCC1 in female infertility.

Effect-based monitoring of chemical hazards in drinking water from source to tap: seasonal trends over 2 years of sampling

Drinking water producers have a far-reaching responsibility to provide safe, clean and wholesome drinking water, using water resources possibly effected by the thousands of chemicals used in societies’ daily life. This study has monitored chemical hazards in drinking water from source to tap, using effect-based methods. The study was conducted at a Swedish drinking water treatment plant sourcing lake water and aimed to investigate potential seasonal variations in both the raw water and water after different treatment steps. Furthermore, a granular activated carbon (GAC) pilot facility was evaluated. Samples were analyzed for estrogenicity, androgenicity, aryl hydrocarbon receptor (AhR) activity, oxidative stress (Nrf2) response and genotoxicity (micronucleus formation). We observed seasonal differences in oxidative stress and genotoxic effects in both raw and drinking water with higher activities during the late fall of each year. The removal efficiency for both oxidative stress and genotoxicity was limited in the full-scale treatment process and occasionally the genotoxicity was also detected in outgoing drinking water from the treatment plant and in samples collected at consumers tap on the distribution network. AhR activity was present in all raw water samples and the removal was limited. Estrogenic activities were observed in most of the raw water samples but in contrast to the other parameters estrogenicity was effectively reduced by the full-scale conventional treatment. The GAC pilot treatment was generally more efficient than the full-scale conventional treatment in removing all observed bioactivities and could be a viable complement to the current treatment to assure drinking water free from genotoxic compounds. Genotoxic activities in drinking water was observed while all currently regulated chemical parameters were fulfilled. This highlights the need for effect-based monitoring in efforts to ensure the chemical safety of drinking water, as target chemical analysis of single compounds will overlook both unknown hazardous compounds as well as potential mixture effects.Graphical

Evaluation of the impact of olive milling on the mineral oil contamination of extra‐virgin olive oils

AbstractMineral oil saturated (MOSH) and aromatic hydrocarbons (MOAH) are environmental and processing contaminants also found in extra‐virgin olive oil. Knowledge on contamination sources can help minimize them. The main objective of this work was to investigate the impact of milling operations. To this purpose, samples from 25 processing lines (at 5 different processing stages) were analyzed by online high‐performance liquid chromatography—gas chromatography—flame ionization detection. A protocol for eliminating endogenous n‐alkanes was tested and applied when necessary. Generally, transport to the mill had a negligible impact. The washing step had a mitigation impact, more evident on samples with higher contamination. On average, total MOSH decreased of 2.1 mg kg–1. Despite the reduction determined by washing, the entire milling process resulted in an increase in contamination (&gt; 30%) for 20% of the processing lines. Total average MOSH and MOAH contamination increased by 2.3 and 0.6 mg kg–1, respectively.Practical Applications: This work aims to improve the knowledge on the presence and sources of mineral oil hydrocarbons (MOH), contaminants of petrogenic origin, in extra‐virgin olive oil. In particular, this work investigates the impact of processing at the mill, including the transport stage, as well as the potential of the washing step in reducing the contamination. For the first time, a systematic study on this topic has been carried out. The knowledge of the contribution of individual steps in the production process to final product contamination is of paramount importance in identifying critical points on which to take action to mitigate contamination, and this is of great interest for all operators of the sector and for protecting consumer health, especially when considering possible presence of MOAH, which may include genotoxic and carcinogenic compounds.

Exploration of Teratogenic and Genotoxic Effects on Model Organism Drosophila melanogaster.

Drosophila melanogaster is one of the crucial in vivo models in terms of analyzing the toxicity of various unknown chemicals. Every part of the fly serves as a model in metabolic and therapeutic approaches. Genotoxic and teratogenic compounds are exposed to Drosophila through the oral route. Further, the toxicity of genotoxic compounds is analyzed in Drosophila's gut, hemolymph, and phenotype. The toxicity of teratogen compounds is also analyzed using a Drosophila embryo. The current chapter summarizes several techniques that are used to detect the genotoxicity and teratogenicity of any unknown compound in this model.

Interlaboratory validation of the ToxTracker assay: An in vitro reporter assay for mechanistic genotoxicity assessment.

ToxTracker is a mammalian cell reporter assay that predicts the genotoxic properties of compounds with high accuracy. By evaluating induction of various reporter genes that play a key role in relevant cellular pathways, it provides insight into chemical mode-of-action (MoA), thereby supporting discrimination of direct-acting genotoxicants and cytotoxic chemicals. A comprehensive interlaboratory validation trial was conducted, in which the principles outlined in OECD Guidance Document 34 were followed, with the primary objectives of establishing transferability and reproducibility of the assay and confirming the ability of ToxTracker to correctly classify genotoxic and non-genotoxic compounds. Reproducibility of the assay to predict genotoxic MoA was confirmed across participating laboratories and data were evaluated in terms of concordance with in vivo genotoxicity outcomes. Seven laboratories tested a total of 64 genotoxic and non-genotoxic chemicals that together cover a broad chemical space. The within-laboratory reproducibility (WLR) was up to 98% (73%-98% across participants) and the overall between-laboratory reproducibility (BLR) was 83%. This trial confirmed the accuracy of ToxTracker to predict in vivo genotoxicants with a sensitivity of 84.4% and a specificity of 91.2%. We concluded that ToxTracker is a robust in vitro assay for the accurate prediction of in vivo genotoxicity. Considering ToxTracker's robust standalone accuracy and that it can provide important information on the MoA of chemicals, it is seen as a valuable addition to the regulatory in vitro genotoxicity battery that may even have the potential to replace certain currently used in vitro battery assays.

Development and validation of a human bronchial epithelial spheroid model to study respiratory toxicity in vitro.

The use of laboratory animals in research has been extensively criticized. While most of the critique has been centered around the ethical aspect, also the economic and scientific aspects have been frequently mentioned as points of concern. As a result, the use of alternative methods has gradually become more enticing. The most used alternatives to laboratory animals are the 2D monolayer cell cultures. However, the limited translatability of these monolayer cell cultures to in vivo has led to the development of 3D cell cultures that are believed to better capture the in vivo physiology and pathology. Here we report on the development of a physiologically more relevant 3D cell model (spheroids) comprised of human bronchial epithelial (16HBE14o-) cells, for use in respiratory toxicity research. Culturing 16HBE14o-cells as hanging-drops led to the formation of stable spheroids which showed an increased expression of CLDN1 when compared to 2D monolayer cultured cells. In addition, cell-cycle analysis revealed an increased sub-G0 population and signs of G0/G1 arrest in spheroids. Afterwards, standard operating procedures (SOPs) were established, and existing protocols optimized, for compatibility with spheroids. Spheroids were successfully used to assess cytotoxicity, genotoxicity, apoptosis/necrosis, and oxidative stress after exposure to known cytotoxic or genotoxic compounds. The development of the bronchial epithelial spheroids and the establishment of SOPs can contribute to amore reliable toxicity assessment of chemicals and may aid in bridging the gap between in vivo and in vitro experiments.