Does the Symbiotic Relationship Between Hydra Viridissima and Photoautotrophic Alga Provide an Evolutionary Advantage in Protecting DNA against Damage by the Cytotoxic or Genotoxic Mode of Action of Environmental Stressors?

The aim of this paper was to evaluate whether symbiotic cooperation between green hydra (Hydra viridissima) and photoautotrophic alga gives higher resistance of the preservation of DNA integrity compared to brown hydra (Hydra oligactis). Norflurazon concentrations were 0.061 or 0.61 mg/L and UV-B light 254 nm, 0.023mWcm- 2 applied separately or simultaneously. By alkaline comet assay primary DNA damage was assessed and cytotoxicity by fluorescent staining. Norflurazon at 0.61 mg L- 1 significantly increased DNA damage in brown hydras compared to the control (6.17 ± 0.6 µm, 5.2 ± 1.7% vs. 2.9 ± 0.2 µm, 1.2 ± 0.2%). Cytotoxicity was significantly elevated, being higher in brown hydras (25.7 ± 3.5% vs. 8.2 ± 0.2%). UV-B irradiation induced significant DNA damage in brown hydras (13.5 ± 1.0 µm, 4.1 ± 1.0%). Simultaneous exposure to UV-B and norflurazon led to a synergistic DNA damaging. The frequency of cytotoxicity and hedgehog nucleoids was more pronounced in brown (78.3 ± 9.4%; 56.4 ± 6.0%) than in green hydras (34.7 ± 2.5%; 24.2 ± 0.6%). Evolutionary established symbiotic cooperation proved to provide resistance against cyto/genotoxicity.

Evaluation of Cytotoxic and Genotoxic Effects in Buccal Mucosal Cells in Non-Smokers and Users of Traditional Combustible Tobacco Products and Non-Combustible Alternatives.

AIMS/OBJECTIVES: The aim of this cross-sectional observational study was to investigate cytogenetic damage to the buccal mucosa in non-smokers and consumers of traditional combustible tobacco products and non-combustible alternatives. METHODS: A total of 160 participants were divided into four groups according to the type of product used, including non-smokers, users of conventional combustible tobacco (cigarettes), heated tobacco, and electronic, tobacco-free vapor products (e-cigarettes). Buccal mucosa samples were analyzed using the micronucleus cytome assay to assess cytotoxic and genotoxic damage. RESULTS: E-cigarette users showed significantly higher values for all tested parameters in the micronucleus test compared to non-smokers (p < 0.05). Similarly, users of tobacco heating products showed an increase in all parameters (p < 0.05), with the exception of the number of cells with micronuclei. Conventional cigarette smokers showed a notable increase in the number of binucleated cells and cells with karyorrhexis and karyolysis (p ≤ 0.05). When assessing the differences between users of traditional combustible tobacco products and non-combustible alternatives, these did not appear to be significant, except for e-cigarette users, who had significantly more cells with condensed chromatin (p ≤ 0.001), while users of tobacco heating products had more pyknotic cells (p ≤ 0.001). CONCLUSION: The results of this study underscore the heightened occurrence of cytotoxic and genotoxic damage in users of both conventional combustible tobacco products and non-combustible alternatives compared to non-smokers, emphasizing the detrimental impact of these products on the oral mucosa.

Assessment of Cytotoxic and Genotoxic Effect of Modern Dental Materials in vivo.

Objectives: The aim of the study was to assess the biocompatibility of modern composite and amalgam dental fillings. Material and Methods: The research was conducted on 150 healthy patients between the ages of 10 and 20 who had amalgam and composite fillings between 6 and 12 months. Under in vivo conditions, a swab of buccal cells near the fillings was taken, and the cytotoxic and genotoxic impact of composite and amalgam fillings on these cells was analyzed using the extended micronucleus test (cytomeassay). Results: The results showed statistically significant differences between the groups of subjects with amalgam and composite fillings and subjects without fillings for the following parameters: number of micronuclei (p=0.006), number of buds (p<0.001), number of binuclear cells (p<0.001), number of nucleoplasmic bridges (p<0.001).The number of micronuclei was statistically significantly higher in the group of subjects with amalgam and composite fillings compared to the group without fillings. The results for nuclear buds, for the number of binuclear cells and the number of nucleoplasmic bridges showed that the group with amalgam fillings had a statistically significantly higher number of these changes compared to other groups.The results of the analysis of the relationship between the parameters of the micronucleus test and the number of amalgam and composite surfaces did not show statistically significant values. Parameters indicating cell cytotoxicity were not statistically significantly elevated in subjects with fillings. The results of the analysis of the influence of the patients' lifestyle on the results of the micronucleus test showed statistically significant results for certain predictors (diagnostic X-ray radiation, coffee consumption, consumption of cooked, dried meat and baked food). Conclusion: Based on the results, it can be concluded that the buccal cells of subjects with amalgam fillings showed the highest degree of genotoxic changes, followed by those with composite fillings and the least buccal cells of patients without fillings.

Safety and efficacy of a feed additive consisting of 25-hydroxycholecalciferol (produced by Pseudonocardia autotrophicaDSM 32858) for all pigs, all poultry for fattening and ornamental birds and other poultry species (Huvepharma NV).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of a feed additive consisting of 25-hydroxycholecalciferol (produced by Pseudonocardia autotrophica DSM 32858) for all pigs, all poultry for fattening and ornamental birds and other poultry species. The production strain P. autotrophica DSM 32858 is not genetically modified however, uncertainties remain on the possible presence of its viable cells in the final product. Due to the lack of adequate safety data and uncertainty on the presence of nano particles, the FEEDAP Panel cannot conclude on the safety of the additive for the target species and the consumer. The additive was shown not to be irritant to skin or eyes and it is not a skin sensitiser. Considering the low dusting potential of the additive, the FEEDAP Panel concluded that the exposure through inhalation is unlikely. However, the FEEDAP Panel considered that uncertainties remain on genotoxicity and on the possible presence of viable cells of P. autotrophica DSM 32858 in the final product which might have an impact on the safety for the users. The use of the feed additive is considered safe for the environment. The Panel concluded that the additive has a potential to be efficacious under the proposed conditions of use.

Safety and efficacy of the feed additive consisting of 6-phytase (produced by Aspergillus oryzaeDSM 33699) (RONOZYME® Hiphos GT/L) for poultry, pigs for fattening, weaned piglets and sows (DSM Nutritional Products Ltd).

The additive RONOZYME® Hiphos (GT/L) contains 6-phytase produced with a genetically modified strain of the filamentous fungus Aspergillus oryzae, it is currently authorised for poultry, pigs for fattening, weaned piglets and sows. The applicant has requested to change the production strain, substituting strain A. oryzae DSM 22594 for A. oryzae DSM 33699. RONOZYME® Hiphos (GT/L), manufactured with the production strain A. oryzae DSM 33699, did not give rise to safety concerns with regard to the genetic modification of the production strain. No viable cells of the production strain nor its recombinant DNA were detected in an intermediate product representative of both final forms of the additive. RONOZYME® Hiphos (GT/L) was considered safe for poultry, pigs for fattening, weaned piglets and sows at the recommended inclusion levels of 500-4,000 FYT/kg complete feed. The use of RONOZYME® Hiphos GT and L manufactured with the production strain A. oryzae DSM 33699 raised no concerns for consumers. In the absence of data on the final formulations, the Panel could not conclude on the potential of the additive to be irritant to eyes or skin, or a skin sensitiser. Due to the proteinaceous nature of the active substance, the additive was considered a respiratory sensitiser. The additive manufactured by A. oryzae DSM 33699 raises no safety concerns for the environment. The additive has the potential to be efficacious in poultry, pigs for fattening, weaned piglets and sows at 500 FYT/kg complete feed.

Evaluation of Toxic Effects Induced by Sub-Acute Exposure to Low Doses of α-Cypermethrin in Adult Male Rats.

To contribute new information to the pyrethroid pesticide α-cypermethrin toxicity profile, we evaluated its effects after oral administration to Wistar rats at daily doses of 2.186, 0.015, 0.157, and 0.786 mg/kg bw for 28 days. Evaluations were performed using markers of oxidative stress, cholinesterase (ChE) activities, and levels of primary DNA damage in plasma/whole blood and liver, kidney, and brain tissue. Consecutive exposure to α-cypermethrin affected the kidney, liver, and brain weight of rats. A significant increase in concentration of the thiobarbituric acid reactive species was observed in the brain, accompanied by a significant increase in glutathione peroxidase (GPx) activity. An increase in GPx activity was also observed in the liver of all α-cypermethrin-treated groups, while GPx activity in the blood was significantly lower than in controls. A decrease in ChE activities was observed in the kidney and liver. Treatment with α-cypermethrin induced DNA damage in the studied cell types at almost all of the applied doses, indicating the highest susceptibility in the brain. The present study showed that, even at very low doses, exposure to α-cypermethrin exerts genotoxic effects and sets in motion the antioxidative mechanisms of cell defense, indicating the potential hazards posed by this insecticide.

Clinical Prospective Assessment of Genotoxic Effects of Dental Implants in Gingival Epithelial Cells.

Objectives: Although titanium-based implants are considered bioinert, it has been found that they are subject to corrosion and wear. This study aimed to evaluate the cytotoxic and genotoxic potential of two implant systems in gingival epithelial cells. Material and methods: Gingival swabs were taken three times from 91 subjects. The first swab was taken before dental implant placement, the second swab 90 days after dental implant placement and the third swab 21 days following the healing abutment placement. DNA damage was analyzed using the micronucleus test. Tested dental implants with corresponding healing abutments were Ankylos and Dentium SuperLine. Results: Of all scored forms of cytogenetic damage in gingival cells of individuals after implementation of tested dental implant systems, only an increase in the number of binucleated cells (P ≤ 0.001) was significant in contrast to control values for both tested implant systems, 90 days after dental implant placement and 21 days following the healing abutment placement. Conclusion: It may be concluded that there are no titanium-based implant dependent cytogenetic damage in gingival epithelial cells. A slight increase in cytogenetic damage has been observed but it is of no biological relevance and might be associated with healing abutment induced effect.

The effect of low doses of chlorpyrifos on blood and bone marrow cells in Wistar rats.

The aim of this study was to investigate the genotoxic potential of low doses of chlorpyrifos (CPF) on blood and bone marrow cells in adult male Wistar rats. CPF was administered by oral gavage at daily doses of 0.010, 0.015, and 0.160 mg/kg of body weight (bw) for 28 consecutive days. Positive control (PC) was administered 300 mg/kg bw/day of ethyl methane sulphonate (EMS) for the final three days of the experiment. Toxic outcomes of exposure were determined with the in vivo micronucleus (MN) assay and alkaline comet assay. The 28-day exposure to the 0.015 mg/kg CPF dose, which was three times higher than the current value of acute reference dose (ARfD), reduced body weight gain in rats the most. The in vivo MN assay showed significant differences in number of reticulocytes per 1000 erythrocytes between PC and negative control (NC) and between all control groups and the groups exposed to 0.015 and 0.160 mg/kg bw/day of CPF. The number of micronucleated polychromatic erythrocytes per 2000 erythrocytes was significantly higher in the PC than the NC group or group exposed to 0.015 mg/kg bw/day of CPF. CPF treatment did not significantly increase primary DNA damage in bone marrow cells compared to the NC group. However, the damage in bone marrow cells of CPF-exposed rats was much higher than the one recorded in leukocytes, established in the previous research. Both assays proved to be successful for the assessment of CPFinduced genome instability in Wistar rats. However, the exact mechanisms of damage have to be further investigated and confirmed by other, more sensitive methods.

Safety and efficacy of a feed additive consisting of endo-1,4-ß-xylanase produced by Komagataella phaffii DSM 33574 (Xylamax) for chickens and turkeys for fattening, chickens reared for laying/breeding, turkeys reared for breeding and minor poultry species for fattening or raised to the point of lay (BioResource international, Inc.).

Following a request from the European Commission, the EFSA Panel on Additives and Products of Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of the product containing endo-1,4-ß-xylanase produced by Komagataella phaffii DSM 33574 (Xylamax) as a zootechnical additive in chickens for fattening, chickens reared for laying/breeding, turkeys for fattening, turkeys reared for breeding and minor poultry species for fattening or raised to the point of lay. The production strain is genetically modified. No viable cells nor recombinant DNA of the production strain were detected in the final product. Therefore, the Panel concluded that the additive does not pose any safety concern regarding the production strain. Based on the no observed adverse effect level identified in a subchronic oral toxicity study in rats, the Panel concluded that Xylamax is safe for all poultry species for fattening or reared to the point of lay. Considering the production strain and the results obtained in the genotoxicity studies, the Panel concluded that the additive is safe for the consumers. The Panel also concluded that Xylamax is not irritant to the skin but should be considered a potential eye irritant and a respiratory sensitiser. No conclusions could be drawn on the potential of the additive to cause skin sensitisation. The use of the product as a feed additive is of no concern for the environment. The FEEDAP Panel concluded that the additive has the potential to be efficacious at 10,000 XU/kg feed in chickens for fattening. This conclusion was extended/extrapolated to chickens reared for laying/breeding, turkeys for fattening, turkeys reared for breeding and minor poultry species for fattening or raised to the point of lay.

Ochratoxin A potentiates citrinin accumulation in kidney and liver of rats.

Ochratoxin A (OTA) and citrinin (CTN) are nephrotoxic mycotoxins often found together in grain. The aim of this study was to measure their accumulation in the kidney and liver of adult male Wistar rats, see how it would be affected by combined treatment, and to determine if resveratrol (RSV) would decrease their levels in these organs. The rats received 125 or 250 mg/kg bw of OTA by gavage every day for 21 days and/or 20 mg/kg bw of CTN a day for two days. Two groups of rats treated with OTA+CTN were also receiving 20 mg/kg bw of RSV a day for 21 days. In animals receiving OTA alone, its accumulation in both organs was dose-dependent. OTA+CTN treatment resulted in lower OTA but higher CTN accumulation in both organs at both OTA doses. RSV treatment increased OTA levels in the kidney and liver and decreased CTN levels in the kidney. Our findings point to the competition between CTN and OTA for organic anion transporters 1 and 3.

ASSESSMENT OF CYTOGENETIC DAMAGE TO EXFOLIATED GINGIVAL CELLS IN PATIENTS WITH CHRONIC GENERALIZED PERIODONTITIS.

The aim of this cross-sectional study was to investigate the occurrence of chromosomal abnormalities through the frequency of micronuclei and other genomic damage markers in patients with chronic generalized periodontitis and without periodontal disease. Micronucleus assay was performed in exfoliated gingival epithelial cells of 35 patients with generalized chronic periodontitis and 30 control subjects with healthy periodontium. Full mouth clinical examination was performed to define periodontal condition. The mean number of cells with micronuclei observed in chronic periodontitis and control groups was 1.8 (±1.49) and 2.0 (±1.34), respectively. Differences between the groups were not significant (p=0.574). Compared to control subjects, patients with chronic periodontitis showed a significant increase in the number of binucleated cells (p≤0.001) and number of cells with nucleoplasmic bridges (p=0.042). Study results indicated that chronic periodontitis was not associated with higher occurrence of chromosomal damage in gingival cells compared to individuals with healthy periodontium.

Assessment of transplacental and lactational genotoxicity of tembotrione in Wistar rats at different developmental stages by alkaline comet assay.

This paper assessed the potential of trans-placental and -lactational genotoxicity and oxidative stress induction of tembotrione, a naturally derived allelopathic herbicide. Several treatment protocols were applied to measure primary DNA damage by alkaline comet assay in leucocytes and liver. To address the oxidative stress induction, TBARS, ROS, SOD, CA, GSH-Px activity were recorded. The dams were treated from the first gestation day and pups sacrificed after birth. The second treatment protocol comprised treating the dams during gestation and lactation and sacrificing the pups at weaning. The third group of pups comprised offspring of dams that were treated in gestation and lactation and sacrificed in puberty. To address translactational genotoxicity, dams were treated in lactation only. Dams treated in gestation and lactation were sacrificed after reentering the estrous cycle and analyzed for DNA damage and oxidative stress. Tembotrione doses encountered in everyday human exposure, as estimated by the EFSA, were applied in dam treatment in consecutive days (ADI: 0.0004 mg/kg b.w./day, AOEL: 0.0007 mg/kg b.w./day, 1/500 LD50 4.0 mg/kg b.w./day). Although we observed mitigated DNA integrity at the dose of 4.0 mg/kg/b.w./day in female pubertal rats, we can conclude that at the conditions employed in the study low doses of tembotrione do not pose a risk for DNA damage of the offspring of treated dams. Contrary to this, the highest dose significantly affected all the oxidative stress parameters in the liver and plasma of pubertal females, CAT and GSH-Px in the liver of males and ROS and CAT of dams.

Assessment of Cytotoxic and Genotoxic Effect of Fissure Sealants in Buccal Epithelial Cells.

AIM: The main purpose of this study was to assess the genotoxic and cytotoxic effect of fissure sealants on buccal epithelial cells. MATERIAL AND METHODS: The study was conducted on 45 patients (27 girls and 18 boys), seven to 16 years of age (age mean 12.09 ± 2.20). Buccal swabs were collected before (T0), seven (T1), 30 (T2) and 90 days (T3) consequently after fissure sealant placement (Helioseal F®, Equia Fil®, Constic®). Patients or legal guardians filled in the questionnaire regarding the demographic data (age, gender), dietary habits, health status, medication usage, and recent X-ray exposure. DNA damage was analyzed using the micronucleus test. RESULTS: Statistically significant difference in the number of buccal cells with condensed chromatin was found between T0 (time before fissure sealant placement) and T3 (90 days after fissure sealant placement) period for Helioseal F® (P = 0.025). For the other two analyzed materials, no difference was observed during the tested period. There was no difference between materials in the same sampling time. CONCLUSION: Apart from an increase in cells with condensed chromatin 90 days after the placement of Helioseal F®, no other nuclear abnormalities were observed for tested fissure sealants. Although these sealants have now largely been used, it is of high importance that their biocompatibility is checked continuously, especially in in vivo clinical studies.

Safety evaluation of the food enzyme cellulase from the non-genetically modified Penicillium funiculosum strain DP-Lzc35.

The food enzyme cellulase (4-(1,3;1,4)-ß-d-glucan 4-glucanohydrolase; EC 3.2.1.4) is produced with the non-genetically modified Penicillium funiculosum strain Lzc35 by Danisco US Inc. The cellulase is intended to be used in distilled alcohol production, baking and brewing processes. Since residual amounts of total organic solids (TOS) are removed by distillation, dietary exposure was only calculated for baking and brewing processes. Based on the proposed maximum use levels, dietary exposure to the food enzyme-TOS was estimated to be up to 0.416 mg TOS/kg body weight (bw) per day. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 84 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 200. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood is considered to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Effects of low-level imidacloprid oral exposure on cholinesterase activity, oxidative stress responses, and primary DNA damage in the blood and brain of male Wistar rats.

Imidacloprid is a neonicotinoid insecticide that acts selectively as an agonist on insect nicotinic acetylcholine receptors. It is used for crop protection worldwide, as well as for non-agricultural uses. Imidacloprid systemic accumulation in food is an important source of imidacloprid exposure. Due to the undisputable need for investigations of imidacloprid toxicity in non-target species, we evaluated the effects of a 28-day oral exposure to low doses of imidacloprid (0.06 mg/kg b. w./day, 0.8 mg/kg b. w./day and 2.25 mg/kg b. w./day) on cholinesterase activity, oxidative stress responses and primary DNA damage in the blood and brain tissue of male Wistar rats. Exposure to imidacloprid did not cause significant changes in total cholinesterase, acetylcholinesterase and butyrylcholinesterase activities in plasma and brain tissue. Reactive oxygen species levels and lipid peroxidation increased significantly in the plasma of rats treated with the lowest dose of imidacloprid. Activities of glutathione-peroxidase in plasma and brain and superoxide dismutase in erythrocytes increased significantly at the highest applied dose. High performance liquid chromatography with UV diode array detector revealed the presence of imidacloprid in the plasma of all the treated animals and in the brain of the animals treated with the two higher doses. The alkaline comet assay results showed significant peripheral blood leukocyte damage at the lowest dose of imidacloprid and dose-dependent brain cell DNA damage. Oral 28-day exposure to low doses of imidacloprid in rats resulted in detectable levels of imidacloprid in plasma and brain tissue that directly induced DNA damage, particularly in brain tissue, with slight changes in plasma oxidative stress parameters.

Safety evaluation of the food enzyme triacylglycerol lipase from the genetically modified Ogataea polymorpha strain DP-Jzk33.

The food enzyme triacylglycerol lipase (triacylglycerol acylhydrolase EC 3.1.1.3) is produced with the genetically modified Ogataea polymorpha strain DP-Jzk33 by Danisco US Inc. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and recombinant DNA. It is intended to be used in baking and cereal-based processes. Based on the maximum use levels recommended for baking and cereal-based processes and individual data from the EFSA Comprehensive European Food Database, dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.520 mg TOS/kg body weight (bw) per day. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 669 mg TOS/kg bw per day, the highest dose tested. Comparison with the estimated dietary exposure results in a margin of exposure of at least 1,287. A search was made of the similarity of the amino acid sequence of the lipase to those of known allergens and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood of such reactions to occur is likely to be low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme xylose isomerase from the genetically modified Streptomyces rubiginosus strain DP-Pzn37.

The food enzyme is a d-xylose aldose-ketose-isomerase (EC 5.3.1.5) produced with the genetically modified Streptomyces rubiginosus strain DP-Pzn37 by Danisco US Inc. Although the production strain contains antibiotic resistance genes, the food enzyme was shown to be free from viable cells of the production organism and its DNA. The food enzyme is intended to be used in an immobilised form for the isomerisation of glucose for the production of high fructose syrups. Residual amounts of total organic solids (TOS) are eliminated by the use of an immobilised food enzyme and further removed by the purification steps applied during the production of high fructose syrups using the immobilised enzyme; consequently, dietary exposure was not calculated. Genotoxicity tests did not raise safety concerns. The systemic toxicity was assessed by a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 85.2 mg TOS/kg body weight (bw) per day, the highest dose tested. Similarity of the amino acid sequence to those of known allergens was searched and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded, but the likelihood is considered to be low. Based on the data provided, the immobilisation process and the removal of total organic solids during the production of high fructose syrups, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Evaluation of oxidative stress responses and primary DNA damage in blood and brain of rats exposed to low levels of tembotrione.

Tembotrione is a rather novel pesticide, usually used for post-emergence weed control. Even though its use is rapidly growing, it is not followed by an adequate flow of scientific evidence regarding its toxicity towards non-target organisms. We evaluated the potential of low doses of tembotrione to induce oxidative stress and cytogenetic damage in blood and brain cells of adult male Wistar rats. Parameters of lipid peroxidation, glutathione levels, activities of antioxidant enzymes and primary DNA damage were assessed following 28-day repeated oral exposure to doses comparable with the currently proposed health-based reference values. The results of the alkaline comet assay showed that such low doses of tembotrione have the potency to inflict primary DNA damage in both peripheral blood leukocytes and brain of treated rats, even with only slight changes in the oxidative biomarker levels. The DNA damage in blood and brain cells of Wistar rats significantly increased at all applied doses, suggesting that tembotrione genotoxicity is mainly a result of direct interaction with DNA while the induction of oxidative stress responses contributes to DNA instability in a lesser extent. The findings of the present study call for further research using other sensitive biomarkers of effect and different exposure scenarios.

Biomonitoring findings for occupational lead exposure in battery and ceramic tile workers using biochemical markers, alkaline comet assay, and micronucleus test coupled with fluorescence in situ hybridisation.

Manufacture of lead-containing products has long been associated with various health risks. To get an insight into the related genotoxic risks, we conducted a biomonitoring study in 50 exposed workers and 48 matched controls using a battery of endpoints that sensitively detect the extent of genome instability in peripheral blood lymphocytes. The levels of primary DNA damage were estimated with the alkaline comet assay, while cytogenetic abnormalities were determined with the cytokinesis-block micronucleus (CBMN) cytome assay. Additionally, CBMN slides of 20 exposed and 16 control participants were subjected to fluorescence in situ hybridisation (FISH), coupled with pancentromeric probes to establish the incidence of centromere-positive micronuclei, nuclear buds, and nucleoplasmic bridges. Blood lead levels (B-Pb) were measured with atomic absorption spectrometry. To further characterise cumulative effects of occupational exposure, we measured erythrocyte protoporphyrin (EP) concentrations and delta-aminolevulinic acid dehydratase (ALAD) activity in blood. We also assessed the influence of serum folate (S-folate) and vitamin B12 (S-B12) on genome stability. Compared to controls, occupationally exposed workers demonstrated significantly higher B-Pb (298.36±162.07 vs 41.58±23.02), MN frequency (18.71±11.06 vs 8.98±7.50), centromere positive MN (C+ MN) (8.15±1.8 vs 3.69±0.47), and centromere negative MN (C- MN) (14.55±1.80 vs 4.56±0.89). Exposed women had significantly higher comet tail intensity (TI) and length (TL) than control women. Furthermore, workers showed a positive correlation between age and nuclear buds and MN, between MN and years of exposure, and between S-B12 levels and TI and ALAD activity, while a negative correlation was found between TI and B-Pb. These findings suggest that occupational settings in the manufacture of lead-containing products pose significant genotoxic risks, which calls for developing more effective work safety programmes, including periodical monitoring of B-Pb and genetic endpoints.