Reliable Comet assay measurements for detecting DNA damage induced by ionising radiation and chemicals

5-Bromouracil-gracillin (5BrU-G) complex: an APOBEC3-activated therapeutic strategy exploiting cancer-specific enzymatic activity for selective cytotoxicity

Recent cancer treatment development has focused on smart drugs, primarily using nanomaterials as carriers. However, concerns about nanomaterial fate and body clearance have led to exploring alternative approaches. This study presents a novel targeted smart drug that uses normal lymphocytic cells as carriers and exploits cancer microenvironment characteristics for drug release, avoiding systemic damage. The research investigated a complex combining gracillin (natural carrier) and the chemotherapeutic agent 5-bromouracil (5-BrU). Molecular docking showed the 5BrU-G complex had superior binding affinity (- 7.96 kcal mol-1) to glycosylated adhesion domain of human T lymphocyte glycoprotein CD2 (1CDB) cell surface receptors in silico. The complex was successfully synthesized through double replacement, precipitation, and neutralization reactions, confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cytotoxic and genotoxic studies revealed the selectivity of 5BrU-G against cancer cells (MDA-MB-231 and Caco-2) while saving normal cells (MCF-10A and CCD 841 CoN). Unlike 5-BrU alone, which showed significant genotoxicity in normal cells, the 5BrU-G complex demonstrated minimal toxic effects. The selective targeting mechanism of 5BrU-G relies on APOBEC3 enzyme activity, which is elevated in cancer cells but is absent in normal cells. This was confirmed when APOBEC3 inhibition prevented the complex's cancer-killing activity. This novel approach offers promising alternatives for improving cancer therapy efficacy while reducing side effects.

Slightly increased level of DNA migration in the comet assay: does statistical significance equal biological significance?

In the comet assay, DNA damage is assessed by differences in DNA migration from gel-embedded nucleoids. Even a small difference in DNA migration between exposure groups can be statistically significant but may invite speculation about the biological significance of such slight increases in DNA migration. A small difference can be defined as a net difference of 1-2% Tail DNA, but background levels of DNA migration typically vary already more than 1-2% Tail DNA between studies. Here, we have used studies on ionizing radiation to assess the lowest detectable differences in DNA migration; variation in exposure-effect relationships; variation in central tendencies of DNA migration; unsystematic (residual) variation; and the actual number of lesions detectable with the comet assay. A total of 51 studies on ionizing radiation exposure in mammalian cells have been systematically reviewed, including results from ring-trial studies where the same batch of irradiated cells has been analysed in different laboratories. Ring-trial studies have shown that unsystematic variation is approximately 4% Tail DNA in studies on ionizing radiation. Studies on ionizing radiation in cell cultures have shown statistically significant effects when the net increase of DNA migration is 0.3-3.1% Tail DNA. Among those experiments, the ones with optimal assay conditions to detect low levels of DNA damage show statistically significant effects with doses of around 0.30 Gy, which corresponds to approximately 350 lesions per diploid cell. However, it has also been shown that the same dose of ionizing radiation can give rise to different levels of DNA migration (i.e. 0.7-7.8% Tail DNA per Gy) in different studies. In summary, the results show that even a small statistically significant difference in DNA migration has biological significance within the same experiment, but comparisons of DNA migration values between studies have limited biological implications.

Eco-genotoxicology: A personal reflection

This reflective commentary provides a personal viewpoint of developments, over the last 3 decades, in the relatively new, multidisciplinary field of 'eco-genotoxicology,' also called 'genetic ecotoxicology'. It aims to outline the scope of the subject area in relation to the historical development of the discipline, critically categorising accomplishments made, taking into account the available information. It also recognises limitations of the existing information and difficulties encountered in this challenging field. Where appropriate, the article makes comparisons to the advances made in human genetic toxicology and radiation biology. The article critically covers the applications of prevailing and emerging tools being used in the field, such as omics, in vitro methodologies, modelling approaches, and artificial intelligence (AI). It also identifies potential areas of development and attempts to credit some of the important personal contributions made in this exciting and challenging subject in relation to human and environmental health.

Assessing the forensic implications of DNA degradation for PMI estimation using comet assay: A systematic review

Accurate post-mortem interval estimation is crucial in forensic investigations, providing essential information for criminal cases. Traditional techniques frequently encounter inaccuracies stemming from environmental and individual variables. The comet assay is a very sensitive technique that detects DNA damage, which has emerged as a promising tool for assessing DNA degradation. This approach can serve as a molecular clock for post-mortem interval estimation, offering a more precise and reliable means of determining the time since death in forensic cases. This systematic review was registered with the International Prospective Register of Systematic Reviews (PROSPERO-CRD42024554907) and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. An extensive electronic database search, including Google Scholar, Embase, Web of Science, PubMed, and Scopus was conducted to find the studies utilizing the comet assay for DNA degradation measurement in post-mortem interval estimation. Two reviewers independently screened and extracted data from eligible studies. The risk of bias tool from the Systematic Review Centre for Laboratory Animal Experimentation was used to evaluate the quality of the research. All six studies fulfilled the inclusion requirements, employing the comet assay on various animal tissues. Studies show a clear relationship between post-mortem interval and degradation of DNA, with varying rates depending on tissue type and environmental factors. The comet assay can detect DNA fragmentation effectively, but difficulties arise from variations in study designs and methodologies. Despite its promise for estimating post-mortem interval, the standardization of protocols is needed to improve reliability and applicability in forensics. Future research should establish standardized methods and explore environmental impacts on DNA degradation.

Assessment of molluscicidal activity of Syzygium aromaticum essential oil against Eobania vermiculata under laboratory and field conditions

The present study focused on assessing the impact of clove oil on adult snails, specifically Eobania vermiculata, due to their detrimental effects on plants and crops. Our investigation aimed to explore both the lethal and sub-lethal toxicity of clove oil under laboratory and field conditions, with the goal of elucidating the mechanisms underlying its toxic effects on E. vermiculata. Snails were exposed to various concentrations of clove oil for one week to determine the LC50, which was calculated to be 5.25% v/v (4.029-6.087). To investigate the molluscicidal effects of clove oil, snails were divided into three groups: control, vehicle-treated (1 % Tween 80), and treated group exposed to sub-lethal concentration (½ LC₅₀) of clove oil for one week. Compared to the control group, the exposure to ½ LC₅₀ of clove oil for 7 days resulted in significant increases in alkaline phosphatase (ALP), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD). Conversely, the level of acetylecholnstrase (AChE) and glutathione peroxidase (GPx) was decreased. Furthermore, testosterone (T) and estrogen (E) levels were significantly reduced. Histological and ultrastructural studies revealed significant tissue disorganization. Additionally, Comet assay results confirmed the genotoxic potential of clove oil on E. vermiculata. Field trials demonstrated a higher reduction in snail populations in plots treated with methomyl (80% and 92% reduction after 7 and 14 days, respectively) compared to those treated with clove oil (64% and 73% reduction, respectively). While slightly less effective than methomyl, clove oil offers a valuable, natural, and residue-free alternative for eco-friendly snail management.

New insights into the oxidative and cytogenotoxic effects of Tetraglyme on human peripheral blood cells

The present study investigated the oxidative and cytogenotoxic potential of Tetraethylene glycol dimethyl ether (known as Tetraglyme) on healthy human peripheral blood lymphocytes, widely used as an in vitro model for assessing the human health risk posed by different chemical compounds. In a first step, Nuclear Magnetic Resonance (1H NMR) spectroscopy, and Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS) were employed to estimate Tetraglyme's stability under a wide range of pH values (4-12), and thus to identify potential by-products. Thereafter, isolated lymphocytes were treated with different concentrations of Tetraglyme (0.02-20 mg L-1) for assessing its oxidative (using the DCFH-DA staining), and cytogenotoxic potential (using the trypan blue exclusion test for estimating cell viability, Comet assay, as well as the cytokinesis-block micronucleus assay, with or without the addition of S9 metabolic activation system). According to the results, Tetraglyme remains stable at pH 4, but two additional derivatives (i.e. 1-[2-(2-ethoxyethoxy)ethoxy]-2-methoxyethane [C9H20O4] and 1-ethoxy-2-(2-ethoxyethoxy)ethane (Diethylene glycol diethyl ether) [C8H18O3]) were found in traces, under alkaline conditions (pH ≥7). Moreover, although Tetraglyme (and/or its derivatives) showed negligible alterations of cell viability (>92 %) in all cases, the pronounced ROS formation, DNA damage, cell proliferation arrest, and MN frequencies in challenged cells are indicative of its oxidative and cytogenotoxic potential. The significant alterations of Cytokinesis-Block Proliferation Index (CBPI) and Micronucleus (MN) frequencies in S9 challenged cells give further evidence for the potential involvement of Tetraglyme's metabolites in the observed cytogenotoxic mode of action. Although not conclusive, the present findings give rise to further research, utilizing different cell types and biological models, for elucidating Tetraglyme's toxic mode of action, as well as its environmental and human risk.

Toxicological assays in the evaluation of safety assessment of fibrinolytic enzymes

Cardiovascular diseases (CVDs) cause 30% of deaths each year, and in 2030, around 23.6 million people will die due to CVDs. The major challenge is to obtain molecules with minimal adverse reactions that can prevent and dissolve blood clots. In this context, fibrinolytic enzymes from diverse microorganism sources have been extensively investigated due to their potential to act directly and specifically on the fibrin clot, preventing side effects and performing potential thrombolytic effects. However, most researches focus on the purification and characterization of proteases, with little emphasis on the mechanism of action and pharmacological characteristics, including toxicity assays which are essential to assess safety and side effects. Therefore, this work aims to emphasize the importance of evaluations indicating the toxicological profile of fibrinolytic proteases through in vitro and in vivo tests. Both types of assays contribute as preclinical stage in drug development and are crucial for clinical applications. This scarcity creates arbitrary barriers to further studies. This work should further encourage the development of studies to ensure the safety and effectivity of fibrinolytic proteases.

Effects of mining activities and municipal wastewaters on element accumulation and integrated biomarker responses of the European chub (Squalius cephalus)

This study aimed to determine concentrations of 29 elements in the gills and liver as well as biomarker response in gills, liver, and blood of European chub from Pek River (exposed to long-term mining activities), and to compare these findings with individuals from Ibar River (influenced by emission of treated municipal wastewater) and Kruščica reservoir (source of drinking water) using inductively-coupled plasma optical emission spectrometry (ICP-OES). The metal pollution index (MPI) was also calculated. Supporting analyses for the detection of the municipal wastewater presence at investigated localities included analyses of microbiological indicators (total coliforms and Escherichia coli) of faecal pollution. We have assessed biomarker responses from molecular to organism level using the condition index, comet assay, micronucleus test, oxidative stress parameters, histopathological alterations, and fluorescence spectroscopy parameters. Multibiomarker analysis was summarized by Integrated Biomarker Response v2 (IBRv2). Among these locations, Kruščica exhibited the lowest, whereas the Pek River displayed the highest values for both categories of indicator bacteria. Due to the porphyry copper ores mining, individuals from Pek River had several times higher Cu concentrations in both gills and liver compared to the other localities which was confirmed by biomarker responses and IBRv2 value. On the contrary, fish from Kruščica reservoir were the least affected by elemental pollution which is also confirmed by low MPI and IBRv2 values. Responses of biomarkers correspond to the elemental accumulation in the liver and gills of the Ibar River are positioned between the Pek River and Kruščica reservoir. Of all the biomarkers analyzed in this study, the condition index was the least sensitive. The results of this study showed that fluorescence spectroscopy may be a method for fast screening of structural changes in gills caused by the pollution burden.

Ameliorative Role of Vitamin C against Cypermethrin Induced Oxidative Stress and DNA Damage in Labeo rohita (Hamilton, 1822) Using Single Cell Gel Electrophoresis

The present study was undertaken to evaluate cypermethrin (CYP)-induced oxidative stress [reactive oxygen species (ROS) and lipid peroxidation (LPO) in gills, muscles, brain, and liver tissues] and DNA damage/genotoxicity (peripheral blood erythrocytes) in a freshwater teleost rohu (Labeo rohita) and the protective role of vitamin C. The LC50 of CYP against rohu was found to be 4.5 µg/L in a semi-static culture system through probit analysis. Fingerlings of rohu were distributed into four groups (Group 1st served as a control, fed 35% protein basal diet and was not exposed to CYP; Group 2nd was fed a basal diet and exposed to CYP; Group 3rd and Group 4th were fed diets supplemented with vitamin C at the rate of 100 and 200 mg/kg diet, respectively, and exposed to CYP). Fingerlings were reared on a basal and vitamin C-supplemented diet for 28 days prior to exposure to CYP. The results indicate a time-dependent significant increase in ROS and LPO (indicated by time course increase in TBARS level) as well as DNA damage in terms of number of comets, % DNA in tail, tail moment, tail length, and olive tail moment after exposure to LC50 of CYP. However, statistically comparable results in both Groups 1st and 4th indicate the protective role of vitamin C. The results reveal the effectiveness of vitamin C as a feed additive for countering pesticides toxicity in Labeo rohita. The current study indicates CYP as a potential genotoxicant for fish and classifies SCGE as a reliable and sensitive tool for assessing DNA damage.

Analyses of oxidative DNA damage among coal vendors via single cell gel electrophoresis and quantification of 8-hydroxy-2'-deoxyguanosine

Looking at the development status of Nigeria and other developing nations, most low-income and rural households often use coal as a source of energy which necessitates its trade very close to the communities. Moreover, the effects of exposure to coal mining activities are rarely explored or yet to be studied, not to mention the numerous street coal vendors in Nigeria. This study investigated the oxidative stress levels in serum and urine through the biomarker 8-OHdG and DNA damage via single cell gel electrophoresis (alkaline comet assay). Blood and urine levels of 8-OHdG from 130 coal vendors and 130 population-based controls were determined by ELISA. Alkaline comet assay was also performed on white blood cells for DNA damage. The average values of 8-OHdG in serum and urine of coal vendors were 22.82 and 16.03 ng/ml respectively, which were significantly greater than those detected in controls (p < 0.001; 15.46 and 10.40 ng/ml of 8-OHdG in serum and urine respectively). The average tail length, % DNA in tail and olive tail moment were 25.06 μm, 18.71% and 4.42 respectively for coal vendors. However, for controls, the average values were 4.72 μm, 3.63% and 1.50 for tail length, % DNA in tail and olive tail moment respectively which were much lower than coal vendors (p < 0.001). Therefore, prolonged exposure to coal dusts could lead to higher serum and urinary 8-OHdG and significant DNA damage in coal vendors observed in tail length, % DNA in tail, and olive tail moment by single cell gel electrophoresis. It is therefore established that coal vendors exhibit a huge risk from oxidative stress and assessment of 8-OHdG with single cell gel electrophoresis has proven to be a feasible tool as biomarkers of DNA damage.

Determination of genoprotection against cyclophosphamide induced toxicity in bone marrow of Swiss albino mice by Moringa oleifera leaves and Tinospora cordifolia stem

The present study aimed to determine the genoprotective activity and safety of Moringa oleifera leave and Tinospora cordifolia stem extracts against cyclophosphamide (CP)-induced genotoxicity utilizing Swiss albino mice. Animals were divided into 14 groups for subacute treatment with either M. oleifera or T. cordifolia extracts daily for 28 days. The extract doses selected were 100, 200 or 400 mg/kg b.w administered orally alone or combined with CP (50 mg/kg b.w. intraperitoneally daily for 5 days). Analyses performed included the comet assay, micronucleus test (MN) in bone marrow cells and sperm head abnormality assay (SHA). M. oleifera and T. cordifolia extracts induced no significant genotoxic effects on somatic and germ cells. In contrast, for all cells examined M. oleifera and T. cordifolia extracts inhibited DNA damage initiated by CP. Taken together data demonstrated that both plant extracts did not exhibit marked genotoxic effects but displayed potential chemoprotective properties against CP-induced genotoxicity in Swiss mice.

Biomarker dosimetry of acute low level of thermal neutrons and radiation adaptive response effect on rats

In this paper, we demonstrated the biological effects of acute low-dose neutrons on the whole body of rats and investigated the impact of that level of neutron dose to induce an in vivo radio-adaptive response. To understand the radio-adaptive response, the examined animals were exposed to acute neutron radiation doses of 5 and 10 mSv, followed by a 50 mSv challenge dose after 14 days. After irradiation, all groups receiving single and double doses were kept in cages for one day before sampling. The electron paramagnetic resonance (EPR) method was used to estimate the radiation-induced radicals in the blood, and some hematological parameters and lipid peroxidation (MDA) were determined. A comet assay was performed beside some of the antioxidant enzymes [catalase enzyme (CAT), superoxide dismutase (SOD), and glutathione (GSH)]. Seven groups of adult male rats were classified according to their dose of neutron exposure. Measurements of all studied markers are taken one week after harvesting, except for hematological markers, within 2 h. The results indicated lower production of antioxidant enzymes (CAT by 1.18-5.83%, SOD by 1.47-17.8%, and GSH by 11.3-82.1%). Additionally, there was an increase in red cell distribution width (RDW) (from 4.61 to 25.19%) and in comet assay parameters such as Tail Length, (from 6.16 to 10.81 µm), Tail Moment, (from 1.17 to 2.46 µm), and percentage of DNA in tail length (DNA%) (from 9.58 to 17.32%) in all groups exposed to acute doses of radiation ranging from 5 to 50 mSv, respectively. This emphasizes the ascending harmful effect with the increased acute thermal neutron doses. The values of the introduced factor of radio adaptive response for all markers under study reveal that the lower priming dose promotes a higher adaptation response and vice versa. Ultimately, the results indicate significant variations in DNA%, SOD enzyme levels, EPR intensity, total Hb concentration, and RDWs, suggesting their potential use as biomarkers for acute thermal neutron dosimetry. Further research is necessary to validate these measurements as biodosimetry for radiation exposure, including investigations involving the response impact of RAR with varied challenge doses and post-irradiation behavior.

Genotoxic effects of sub-lethal doses of nicotine and acetamiprid in neuroblasts of Drosophila melanogaster and Drosophila suzukii

Neonicotinoids form a class of insecticides that are chemically related to nicotine and are widely used in crop protection. They have adverse effects on the neuronal nicotinic acetylcholine receptors (nAChRs). One of the neonicotinoids approved for control of the invasive pest Drosophila suzukii is acetamiprid. Despite concerns regarding its genotoxicity and data indicating the presence of small amounts of this substance in fruits intended for consumption, effects of its low doses on nerve cells are yet to be investigated. To determine whether the neurotoxic effects are species-specific and vary depending on the insecticide present in diet, multigenerational cultures of Drosophila melanogaster and D. suzukii were prepared, in this study, in media supplemented with different concentrations (below the LC50) of acetamiprid and nicotine. Acetamiprid, analogous to nicotine, caused damage to the DNA of neuroblasts in both species, at sublethal concentrations, along with a decrease in mobility, which remained at a similar level over subsequent generations. D. suzukii was found to be more sensitive to nicotine and acetamiprid, due to which the genotoxic effects were stronger even at lower doses of toxins. The results collectively indicated that even low concentrations of acetamiprid affect the stem cells of developing fly brain, and that long-term response to the tested insecticides is species-specific.

Customizable Zr-MOF nanoantidote-based multieffective arsenic detoxification and its extended low-toxic therapy

Arsenic (As) poisoning has become a global public problem threatening human health. Chelation therapy (CT) is the preferred treatment for arsenic poisoning. Nevertheless, efficient and safe arsenic removal in vivo remains a daunting challenge due to the limitations of chelators, including weak affinity, poor cell membrane penetration, and short half-life. Herein, a mercapto-functionalized and size-tunable hierarchical porous Zr-MOF (UiO-66-TC-SH) is developed, which possesses abundant arsenic chemisorption sites, effective cell uptake ability, and long half-life, thereby efficiently removing toxic arsenic in vivo. Moreover, the strong binding affinity of UiO-66-TC-SH for arsenic reduces systemic toxicity caused by off-target effects. In animal trials, UiO-66-TC-SH decreases the blood arsenic levels of acute arsenic poisoning mice to a normal value within 48 h, and the efficacy is superior to clinical drugs 2,3-dimercaptopropanesulfonic acid sodium salt (DMPS). Meanwhile, UiO-66-TC-SH also significantly mitigates the arsenic accumulation in the metabolic organs of chronic arsenic poisoning mice. Surprisingly, UiO-66-TC-SH also accelerates the metabolism of arsenic in organs of tumor-bearing mice and alleviates the side effects of arsenic drugs antitumor therapy. STATEMENT OF SIGNIFICANCE: Arsenic (As) contamination has become a global problem threatening public health. The present clinical chelation therapy (CT) still has some limitations, including the weak affinity, poor cell membrane permeability and short half-life of hydrophilic chelators. Herein, a metal-organic framework (MOF)-based multieffective arsenic removal strategy in vivo is proposed for the first time. Mercapto-functionalized and size-tunable hierarchical porous Zr-MOF nanoantidote (denoted as UiO-66-TC-SH) is accordingly designed and synthesized. After injection, UiO-66-TC-SH can form Zr-O-As bonds and As-S bonds with arsenic, thus enhancing arsenic adsorption capacity, cycling stability and systemic safety simultaneously. The acute arsenic poisoning model results indicate that UiO-66-TC-SH shows superior efficacy to the clinical drug sodium dimercaptopropanesulfonate (DMPS). More meaningfully, we find that UiO-66-TC-SH also accelerates the metabolism of arsenic in organs of tumor-bearing mice and alleviates side effects of arsenic drugs anti-tumor therapy.

Mammalian Cell Genotoxicity of Potable Reuse and Conventional Drinking Waters

Potable reuse water is increasingly part of the water supply portfolio for municipalities facing water shortages, and toxicity assays can be useful for evaluating potable reuse water quality. We examined the Chinese hamster ovary cell acute direct genotoxicity of potable reuse waters contributed by disinfection byproducts (DBPs) and anthropogenic contaminants and used the local conventional drinking waters as benchmarks for evaluating potable reuse water quality. Our results showed that treatment trains based on reverse osmosis (RO) were more effective than RO-free treatment trains for reducing the genotoxicity of influent wastewaters. RO-treated reuse waters were less genotoxic than the local tap water derived from surface water, whereas reuse waters not treated by RO were similarly genotoxic as the local drinking waters when frequent replacement of granular activated carbon limited contaminant breakthrough. The genotoxicity contributed by nonvolatile, uncharacterized DBPs and anthropogenic contaminants accounted for ≥73% of the total genotoxicity. The (semi)volatile DBPs of current research interest contributed 2-27% toward the total genotoxicity, with unregulated DBPs being more important genotoxicity drivers than regulated DBPs. Our results underscore the need to look beyond known, (semi)volatile DBPs and the importance of determining whole water toxicity when assessing the quality of disinfected waters.

Indigo dyes: Toxicity, teratogenicity, and genotoxicity studies in zebrafish embryos

Wastewater released by textile dyeing industries is a major source of pollution. Untreated wastewater released from indigo dyeing operations affects aquatic ecosystems and threatens their biodiversity. We have assessed the toxicity of natural and synthetic indigo dye in zebrafish embryos, using the endpoints of teratogenicity, genotoxicity, and histopathology. The zebrafish embryo toxicity test (ZFET) was conducted, exposing embryos to ten concentrations of natural and synthetic indigo dyes; the 96-hour LC50 values were approximately 350 and 300 mg/L, respectively. Both dyes were teratogenic, causing egg coagulation, tail detachment, yolk sac edema, pericardial edema, and tail bend, with no significant difference in effects between the natural and synthetic dyes. Both dyes were genotoxic (using comet assay for DNA damage). Real-time RT-PCR studies showed upregulation of the DNA-repair genes FEN1 and ERCC1. Severe histological changes were seen in zebrafish larvae following exposure to the dyes. Our results show that indigo dyes may be teratogenic and genotoxic to aquatic organisms, underscoring the need for development of sustainable practices and policies for mitigating the environmental impacts of textile dyeing.

Effects of pyroligneous acid on acute, chronic, and cyto-genotoxicity to earthworms (Eisenia fetida)

The pyroligneous acid (PA), or wood vinegar, is a byproduct of wood carbonization during the slow pyrolysis process. PA is recognized globally as a safe compound for agriculture due to its various beneficial properties, such as antioxidant, antibacterial, antifungal, and termiticidal properties. However, the impact of different PA concentrations on beneficial soil organisms, such as earthworms has not been investigated. The present study aims to understand the effects of different PA concentrations on earthworm Eisenia fetida. The earthworms were exposed to nine different concentrations of PA in soils, including their control. The acute toxicity assay was performed after 14 days of exposure, and the chronic toxicity assay was performed up to 8 weeks after exposure. The results from the acute toxicity assay demonstrated no significant effect on earthworm mortality. The chronic toxicity assay showed that lower PA concentrations (0.01-0.2% of weight/weight PA in soil) promoted cocoon and juvenile production in soils, whereas higher PA concentrations (0.5 and 1%) had a negative effect. These findings highlight the potential of PA to enhance soil fertility at lower concentrations, up to 0.2%, by stimulating worm activity and subsequent manure production. The outcomes of this study have significant implications for the careful management of PA concentrations within agricultural operations.

FLASH Radiotherapy: Expectations, Challenges, and Current Knowledge

Major strides have been made in the development of FLASH radiotherapy (FLASH RT) in the last ten years, but there are still many obstacles to overcome for transfer to the clinic to become a reality. Although preclinical and first-in-human clinical evidence suggests that ultra-high dose rates (UHDRs) induce a sparing effect in normal tissue without modifying the therapeutic effect on the tumor, successful clinical translation of FLASH-RT depends on a better understanding of the biological mechanisms underpinning the sparing effect. Suitable in vitro studies are required to fully understand the radiobiological mechanisms associated with UHDRs. From a technical point of view, it is also crucial to develop optimal technologies in terms of beam irradiation parameters for producing FLASH conditions. This review provides an overview of the research progress of FLASH RT and discusses the potential challenges to be faced before its clinical application. We critically summarize the preclinical evidence and in vitro studies on DNA damage following UHDR irradiation. We also highlight the ongoing developments of technologies for delivering FLASH-compliant beams, with a focus on laser-driven plasma accelerators suitable for performing basic radiobiological research on the UHDR effects.

Baseline and oxidatively damaged DNA in end-stage renal disease patients on varied hemodialysis regimens: a comet assay assessment

Global estimates exhibit that one million people have end-stage renal disease, a disease-state characterized by irreversible loss of kidney structure and function, thus necessitating renal replacement therapy. The disease-state, oxidative stress, inflammatory responses, as well as the treatment procedure can have damaging effects on the genetic material. Therefore, the present study was carried out to investigate DNA damage (basal and oxidative) using the comet assay in peripheral blood leukocytes of patients (n = 200) with stage V Chronic Kidney Disease (on dialysis and those recommended but yet to initiate dialysis) and compare it to that in controls (n = 210). Basal DNA damage was significantly elevated (1.13x, p ≤ 0.001) in patients (46.23 ± 0.58% DNA in tail) compared to controls (40.85 ± 0.61% DNA in tail). Oxidative DNA damage was also significantly (p ≤ 0.001) higher in patients (9.18 ± 0.49 vs. 2.59 ± 0.19% tail DNA) compared to controls. Twice-a-week dialysis regimen patients had significantly elevated % tail DNA and Damage Index compared to the non-dialyzed and to the once-a-week dialysis group implying dialysis- induced mechanical stress and blood-dialyzer membrane interactions as probable contributors to elevated DNA damage. The present study with a statistically significant power implies higher disease-associated as well as maintenance therapy (hemodialysis)-induced basal and oxidatively damaged DNA, which if not repaired has the potential to initiate carcinogenesis. These findings mark the need for improvement and development of interventional therapies for delaying disease progression and associated co-morbidities so as to improve life expectancy of patients with kidney disease.

Overview of Tissue Engineering and Drug Delivery Applications of Reactive Electrospinning and Crosslinking Techniques of Polymeric Nanofibers with Highlights on Their Biocompatibility Testing and Regulatory Aspects

Traditional electrospinning is a promising technique for fabricating nanofibers for tissue engineering and drug delivery applications. The method is highly efficient in producing nanofibers with morphology and porosity similar to the extracellular matrix. Nonetheless, and in many instances, the process has faced several limitations, including weak mechanical strength, large diameter distributions, and scaling-up difficulties of its fabricated electrospun nanofibers. The constraints of the polymer solution's intrinsic properties are primarily responsible for these limitations. Reactive electrospinning constitutes a novel and modified electrospinning techniques developed to overcome those challenges and improve the properties of the fabricated fibers intended for various biomedical applications. This review mainly addresses reactive electrospinning techniques, a relatively new approach for making in situ or post-crosslinked nanofibers. It provides an overview of and discusses the recent literature about chemical and photoreactive electrospinning, their various techniques, their biomedical applications, and FDA regulatory aspects related to their approval and marketing. Another aspect highlighted in this review is the use of crosslinking and reactive electrospinning techniques to enhance the fabricated nanofibers' physicochemical and mechanical properties and make them more biocompatible and tailored for advanced intelligent drug delivery and tissue engineering applications.

Assessing the effects of single and binary exposures of copper and lead on Mytilus galloprovincialis: Physiological and genotoxic approaches

It is becoming increasingly recognised that contaminants are not isolated in their threats to the aquatic environment, with recent shifts towards studying the effects of chemical mixtures. In this study, adult marine mussels (Mytilus galloprovincialis) were exposed to two aqueous concentrations of the essential trace metal, Cu (5 and 32 μg L-1), and the non-essential metal, Pb (5 and 25 μg L-1), both individually and in binary mixtures. After a 14-day exposure, metal accumulation was determined in the digestive gland, gill and mantle tissues by inductively coupled plasma-mass spectrometry following acid digestion, and a number of biochemical, neurotoxic and physiological markers were assessed. These included measurements of DNA damage using comet assay, total glutathione concentration, acetylcholinesterase (AChE) activity and clearance rate. Metal accumulation was greater in the digestive gland and gill than in the mantle, and based on computed free ion concentrations, was greater for Pb than for Cu. Copper exhibited an inhibitory effect on Pb accumulation but Pb did not appear to affect Cu accumulation. Comet assay results revealed DNA damage (i.e., genotoxic effects) in all treatments but differences between the exposures were not significant (p > 0.05), and there were no significant differences in AChE activities between treatments. The most distinctive impacts were a reduction in clearance rate resulting from the higher concentration of Cu, with and without Pb, and an increase in glutathione in the gill resulting from the higher concentration of Cu without Pb. Multivariate analysis facilitated the development of a conceptual model based on the current findings and previously published data on the toxicity and intracellular behaviour of Cu and Pb that will assist in the advancement of regulations and guidelines regarding multiple metal contaminants in the environment.

Backscatter from therapeutic doses of ionizing irradiation does not impair cell migration on titanium implants in vitro

OBJECTIVE

The influence of radiation backscatter from titanium on DNA damage and migration capacity of human osteoblasts (OBs) and mesenchymal stem cells (MSCs) may be critical for the osseointegration of dental implants placed prior to radiotherapy. In order to evaluate effects of radiation backscatter, the immediate DNA damage and migration capacity of OBs and MSCs cultured on titanium or plastic were compared after exposure to ionizing irradiation.

MATERIALS AND METHODS

Human OBs and MSCs were seeded on machined titanium, moderately rough fluoride-modified titanium, or tissue culture polystyrene, and irradiated with nominal doses of 2, 6, 10, or 14 Gy. Comet assay was performed immediately after irradiation, while a scratch wound healing assay was initiated 24 h post-irradiation. Fluorescent live cell imaging documented the migration.

RESULTS

DNA damage increased with higher dose and with backscatter from titanium, and MSCs were significantly more affected than OBs. All doses of radiation accelerated the cell migration on plastic, while only the highest dose of 10 Gy inhibited the migration of both cell types on titanium.

CONCLUSIONS

High doses (10 Gy) of radiation inhibited the migration capacity of both cell types on titanium, whereas lower doses (2 and 6 Gy) did not affect the migration of either OBs or MSCs.

CLINICAL RELEVANCE

Fractionated doses of 2 Gy/day, as distributed in conventional radiotherapy, appear not to cause severe DNA damage or disturb the migration of OBs or MSCs during osseointegration of dental implants.

Assessment of toxicity potential of neglected Mithi River water from Mumbai megacity, India, in zebrafish using embryotoxicity, teratogenicity, and genotoxicity biomarkers

The Mithi River begins at Vihar Lake and flows through the industrial hub of the city of Mumbai, India, and merges with the Arabian Sea at Mahim Creek. The current study was carried out to assess the ecotoxicological effects of the Mithi River surface water in zebrafish (Danio rerio) embryos. Water samples were collected from ten sampling sites (S1 to S10) located along the course of the Mithi River. The toxicity of water samples was assessed using a zebrafish embryo toxicity test (ZFET). Water samples were diluted from all sites at 1:0, 1:2, 1:4, 1:8, 1:16, 1:32, 1:64, and 1:128 times. The lowest and highest LDil 20 values for 96 h were estimated as 9.16 and 74.18 respectively for the S2 and S5 sites. The results of embryotoxicity and teratogenicity assays indicated a significant difference (p < 0.0001) between embryos exposed to control and sampling sites (except S1) for various endpoints such as mortality, egg coagulation, pericardial edema, yolk sac edema, tail bend, and skeletal deformities. The histopathological analysis revealed various lesions, ascertaining the toxic effects of water samples. The comet assay revealed significantly higher DNA damage (except S1) in embryos exposed to sites S5 and S6 with OTM values of 4.46 and 2.48 respectively. The results indicated that the Mithi River is polluted with maximum pollution load at the middle stretches. The study further indicated that the pollutants in the Mithi River (except S1) could potentially be hazardous to the aquatic organisms; therefore, continuous biomonitoring of the river is needed for its revival.

Cytotoxicity and genotoxicity of tributyltin in the early embryonic chick, Gallus gallus domesticus

Tributyltin (TBT) is used in many commercial applications, including pesticides and antifouling paints, due to its biocidal properties. We examined the cytotoxicity and genotoxicity of TBT in the early chick embryo (Gallus gallus domesticus). Chick embryos (11 days) were treated with various doses of TBT to measure LD₅₀ values for 24, 48, and 72 h exposures, which were determined to be 110, 54, and 18 μg/egg, respectively. The embryos were exposed to sub-lethal doses of TBT for evaluation of cytotoxicity and genotoxicity. An increase in the incidence of micronuclei (MN) was observed but it was not statistically significant. Induction of other nuclear abnormalities (ONA) after 72 h TBT exposure was significant. A significant increase in comet assay tail DNA content was also detected in TBT-exposed embryos. Cytotoxicity was also evidenced by alteration in the polychromatic erythrocytes (PCE) to normochromatic erythrocytes (NCE) ratio and by an increase in the erythroblast population in treated organisms. The cytotoxicity and genotoxicity of TBT may have long-term complications in later stages of the life cycle.

Cytotoxicity induced by abamectin in hepatopancreas cells of Chinese mitten crab, Eriocheir sinensis: An in vitro assay

Toxic effects of abamectin on non-target aquatic organisms have been well documented due to its extensive use in both agricultural and aquacultural areas. However, knowledge of the abamectin induced cytotoxicity in crustacean hepatopancreas is still incomplete. In this study, we investigated the cytotoxic effects of abamectin on hepatopancreas cells of Chinese mitten crab, Eriocheir sinensis by an in vitro assay. The results showed that abamectin inhibited cell viability with elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels in a dose-dependent manner. Increased olive tail moment (OTM) values and 8-hydroxy-2'-deoxyguanosine (8-OHdG) contents indicate the DNA damage under abamectin exposure. The up-regulation of the typical apoptosis-related protein BCL2-associated X protein (Bax) and the down-regulation of B cell leukemia/lymphoma 2 (Bcl-2) demonstrate apoptosis in hepatopancreas cells. Meanwhile, the activities of both caspase-3 and caspase-9 were increased, indicating caspase-mediated apoptosis. In addition, qRT-PCR results showed the up-regulation of antioxidant genes superoxide dismutase (SOD) and catalase (CAT). The mRNA expression of Cap 'n' Collar isoform-C (CncC) and c-Jun NH2-terminal kinases (JNK) was also significantly increased, implying the involvement of the Nrf2/MAPK pathway in the antioxidative response. The alteration of innate immune-associated genes Toll-like receptor (TLR) and myeloid differentiation primary response gene 88 (Myd88) also indicates the influence of abamectin on immune status. In summary, the present study reveals the cytotoxicity of abamectin on hepatopancreas cells of E. sinensis and this in vitro cell culture model could be used for further assessment of pesticide toxicity.

AutoComet: A fully automated algorithm to quickly and accurately analyze comet assays

DNA damage is a common cellular feature seen in cancer and neurodegenerative disease, but fast and accurate methods for quantifying DNA damage are lacking. Comet assays are a biochemical tool to measure DNA damage based on the migration of broken DNA strands towards a positive electrode, which creates a quantifiable 'tail' behind the cell. However, a major limitation of this approach is the time needed for analysis of comets in the images with available open-source algorithms. The requirement for manual curation and the laborious pre- and post-processing steps can take hours to days. To overcome these limitations, we developed AutoComet, a new open-source algorithm for comet analysis that utilizes automated comet segmentation and quantification of tail parameters. AutoComet first segments and filters comets based on size and intensity and then filters out comets without a well-connected head and tail, which significantly increases segmentation accuracy. Because AutoComet is fully automated, it minimizes curator bias and is scalable, decreasing analysis time over ten-fold, to less than 3 s per comet. AutoComet successfully detected statistically significant differences in tail parameters between cells with and without induced DNA damage, and was more comparable to the results of manual curation than other open-source software analysis programs. We conclude that the AutoComet algorithm provides a fast, unbiased and accurate method to quantify DNA damage that avoids the inherent limitations of manual curation and will significantly improve the ability to detect DNA damage.

Methanolic fraction of Cassia fistula L. bark exhibits potential to combat oxidative stress and possess antiproliferative activity

Cassia fistula L. is well known for its traditional medicinal properties as an anti-inflammatory, hepatoprotective, antifungal, antibacterial, antimutagenic, and wound healing agent. The aim of the present study was to determine antioxidant, genoprotective, and cytotoxic potential of different fractions of C. fistula bark including hexane (CaMH), chloroform (CaMC), ethyl acetate (CaME), and methanol (CaMM). Among all the fractions studied, CaMM exhibited maximal radical scavenging activity in antioxidant DPPH assay, Superoxide anion radical scavenging assay and nitric oxide radical scavenging assay displayed an IC₅₀ value of 18.95, 29.41, and 13.38 µg/ml, respectively. CaMM fraction possessed the highest phenolic (130.37 mg gallic acid equivalent/g dry weight of extract) and flavonoid (36.96 mg rutin equivalent/g dry weight of fraction) content. Data demonstrated significant positive correlation between polyphenol levels and radical scavenging activity. Single cell gel electrophoresis (Comet assay) exhibited genoprotective potential of C. fistula bark fractions against DNA damage induced by hydrogen peroxide (H₂O₂) in human lymphocytes. CaMM fraction displayed highest protective ability against H₂O₂ induced-toxicity as evidenced by significant decrease in % tail DNA content from 30 to 7% at highest concentration (200 µg/ml). CaMM was found to be rich in catechin, gallic acid, chlorogenic acid, and kaempferol. The phenolic content and antioxidant ability of the fractions was markedly negatively correlated with H₂O₂- induced DNA damage in human lymphocytes. Cytotoxic potential was evaluated against dermal epidermoid carcinoma (A431), pancreatic (MIA PaCa-2) and brain glioblastoma (LN-18) cancer cell lines using MTT assay. Results showed that C. fistula bark fractions possessed highest toxicity against the skin carcinoma cells. CaMM fraction reduced over 50% cell growth at the concentration of 76.72 µg/ml in A431 cells. These findings suggest that fractions of C. fistula bark exhibit potential to be considered as therapeutic agents in various carcinomas.

Protective Effects of Omega-3 Supplementation against Doxorubicin-Induced Deleterious Effects on the Liver and Kidneys of Rats

Anthracycline doxorubicin (DOX) is still widely used as a chemotherapeutic drug for some solid tumors. Although DOX is highly effective, its side effects are limiting factors, such as cardio, nephro and hepatotoxicity. As such, approaches used to mitigate these adverse effects are highly encouraged. Omega 3 (ω-3), which is a class of long-chain polyunsaturated fatty acids, has been shown to have anti-inflammatory and antioxidant effects in preclinical bioassays. Thus, we evaluated the protective effects of ω-3 supplementation on hepatotoxicity and nephrotoxicity induced by multiple DOX administrations in rodents. Male Wistar rats (10 rats/group) were treated daily with ω-3 (400 mg/kg/day) by gavage for six weeks. Two weeks after the first ω-3 administration, the rats received DOX (3.5 mg/kg, intraperitoneal, 1×/week) for four weeks. DOX treatment reduced body weight gain increased systemic genotoxicity and caused liver-related (increase in serum ALT levels, thickness of the Glisson’s capsule, compensatory proliferation and p65 levels) and kidney-related (increase in serum urea and creatinine levels, and incidence of tubular dilatation) deleterious outcomes. In contrast, ω-3 supplementation was safe and abrogated the DOX-related enhancement of systemic genotoxicity, serum urea and creatinine levels. Furthermore, ω-3 intervention reduced by 50% the incidence of kidney histological lesions while reducing by 40–50% the p65 protein level, and the proliferative response in the liver induced by DOX. Our findings indicate that ω-3 intervention attenuated the DOX-induced deleterious effects in the liver and kidney. Therefore, our findings may inspire future mechanistical investigations and clinical interventions with ω-3 on the reported outcomes.

Opioid induces increased DNA damage in prefrontal cortex and nucleus accumbens

Opioid use disorder (OUD) is a chronic disease characterized by compulsive opioid taking and seeking, affecting millions of people worldwide. The high relapse rate is one of the biggest challenges in treating opioid addiction. However, the cellular and molecular mechanisms underlying relapse to opioid seeking are still unclear. Recent studies have shown that DNA damage and repair processes are implicated in a broad spectrum of neurodegenerative diseases as well as in substance use disorders. In the present study, we hypothesized that DNA damage is related to relapse to heroin seeking. To test our hypothesis, we aim to examine the overall DNA damage level in prefrontal cortex (PFC) and nucleus accumbens (NAc) after heroin exposure, as well as whether manipulating DNA damage levels can alter heroin seeking. First, we observed increased DNA damage in postmortem PFC and NAc tissues from OUD individuals compared to healthy controls. Next, we found significantly increased levels of DNA damage in the dorsomedial PFC (dmPFC) and NAc from mice that underwent heroin self-administration. Moreover, increased accumulation of DNA damage persisted after prolonged abstinence in mouse dmPFC, but not in NAc. This persistent DNA damage was ameliorated by the treatment of reactive oxygen species (ROS) scavenger N-acetylcysteine, along with attenuated heroin-seeking behavior. Furthermore, intra-PFC infusions of topotecan and etoposide during abstinence, which trigger DNA single-strand breaks and double-strand breaks respectively, potentiated heroin-seeking behavior. These findings provide direct evidence that OUD is associated with the accumulation of DNA damage in the brain (especially in the PFC), which may lead to opioid relapse.

Biomonitoring of heavy metals and their association with DNA damage in Indian peafowl (Pavo cristatus) under captivity

Environmental pollution and changing climatic conditions are likely to damage biodiversity not only on organismal level but on molecular level as well. The aim of the present study was to find the concentration of heavy metals in soil, water, feed, feathers, and blood and association of heavy metals with DNA damage of P. cristatus. The results showed that lead (Pb) was significantly (P < 0.01) higher in soil and cadmium (Cd) was significantly (P < 0.01) higher in soil and water. Chromium (Cr), zinc (Zn), nickel (Ni), and cobalt (Co) were significant (P < 0.01) in feed. Manganese (Mn) was significantly (P < 0.01) higher in feed and soil (surface). In addition, Pb and Cd concentrations were significant (P < 0.01) in feathers while Cr and Zn concentrations were significantly (P < 0.01) higher in feces. Nickel was significantly (P < 0.01) higher in feathers and eggshell while Mn and Co concentrations were significantly (P < 0.01) higher in blood and feces, respectively. Furthermore, significant positive correlation between Pb (r_s = 0.75; P < 0.05) and Cd (r_s = 0.67; P < 0.05) concentrations in blood with tail DNA was found. It was concluded that heavy metals exist in the soil, water, feathers, and blood and have association with DNA damage of P. cristatus.

Measuring DNA modifications with the comet assay: a compendium of protocols

The comet assay is a versatile method to detect nuclear DNA damage in individual eukaryotic cells, from yeast to human. The types of damage detected encompass DNA strand breaks and alkali-labile sites (e.g., apurinic/apyrimidinic sites), alkylated and oxidized nucleobases, DNA-DNA crosslinks, UV-induced cyclobutane pyrimidine dimers and some chemically induced DNA adducts. Depending on the specimen type, there are important modifications to the comet assay protocol to avoid the formation of additional DNA damage during the processing of samples and to ensure sufficient sensitivity to detect differences in damage levels between sample groups. Various applications of the comet assay have been validated by research groups in academia, industry and regulatory agencies, and its strengths are highlighted by the adoption of the comet assay as an in vivo test for genotoxicity in animal organs by the Organisation for Economic Co-operation and Development. The present document includes a series of consensus protocols that describe the application of the comet assay to a wide variety of cell types, species and types of DNA damage, thereby demonstrating its versatility.

Eco-Friendly Engineered Nanomaterials Coupled with Filtering Fine-Mesh Net as a Promising Tool to Remediate Contaminated Freshwater Sludges: An Ecotoxicity Investigation

The use of eco-friendly engineered nanomaterials represents a recent solution for an effective and safe treatment of contaminated dredging sludge. In this study, an eco-designed engineered material based on cross-linked nanocellulose (CNS) was applied for the first time to decontaminate a real matrix from heavy metals (namely Zn, Ni, Cu, and Fe) and other undesired elements (mainly Ba and As) in a lab-scale study, with the aim to design a safe solution for the remediation of contaminated matrices. Contaminated freshwater sludge was treated with CNS coupled with a filtering fine-mesh net, and the obtained waters were tested for acute and sublethal toxicity. In order to check the safety of the proposed treatment system, toxicity tests were conducted by exposing the bacterium Aliivibrio fischeri and the crustacean Heterocypris incongruens, while subtoxicity biomarkers such as lysosomal membrane stability, genetic, and chromosomal damage assessment were performed on the freshwater bivalve Dreissena polymorpha. Dredging sludge was found to be genotoxic, and such genotoxicity was mitigated by the combined use of CNS and a filtering fine-mesh net. Chemical analyses confirmed the results by highlighting the abetment of target contaminants, indicating the present model as a promising tool in freshwater sludge nanoremediation.

An endophytic Schizophyllum commune possessing antioxidant activity exhibits genoprotective and organprotective effects in fresh water fish Channa punctatus exposed to bisphenol A

BACKGROUND

Oxidative stress is responsible for the onset of several chronic and degenerative diseases. Exogenous supply of antioxidants is reported to neutralize the effects of oxidative stress. Several synthetic antioxidants suffer from various side effects which necessitates the exploration of antioxidant compounds from natural sources. Endophytic fungi residing in the plants are gaining the attention of researchers as a source of novel antioxidants. Majority of the research conducted so far on endophytic fungi has been restricted to the members of phylum ascomycota. Basidiomycota, inspite of their immense bioactive potential remain relatively unexploited. This study aimed to assess the ameliorative effects of an endophytic Schizophyllum commune (basidiomycetous fungus) against oxidative stress associated altered antioxidant levels, genotoxicity and cellular damage to different organs in bisphenol A exposed fresh water fish Channa punctatus.

RESULTS

Good antioxidant and genoprotective potential was exhibited by S. commune extract in in vitro studies conducted using different antioxidant, DNA damage protection, and cytokinesis blocked micronuclei assays. In vivo studies were performed in fresh water fish Channa punctatus exposed to bisphenol A. A significant decrease in the considered parameters for DNA damage (% micronuclei and comet assay) were recorded in fish treated with S. commune extract on comparison with untreated bisphenol A exposed group. The S. commune extract treated fish also exhibited an increase in the level of antioxidant enzymes viz. catalase, superoxide dismutase and glutathione reductase as well as histoprotective effect on various organs. GC-MS analysis revealed the presence of 3-n-propyl-2,4-pentanedione, n-heptadecanol-1, trans-geranylgeraniol, 3-ethyl-2-pentadecanone, 1-heneicosanol and squalene as some of the compounds in S. commune extract.

CONCLUSION

The study highlights the significance of an endophytic basidiomycetous fungus S. commune as a source of antioxidant compounds with possible therapeutic potential.

The Antibacterial and Larvicidal Potential of Bis-(2-Ethylhexyl) Phthalate from Lactiplantibacillus plantarum

Lactic acid bacteria produce a variety of antibacterial and larvicidal metabolites, which could be used to cure diseases caused by pathogenic bacteria and to efficiently overcome issues regarding insecticide resistance. In the current study, the antibacterial and larvicidal potential of Bis-(2-ethylhexyl) phthalate isolated from Lactiplantibacillus plantarum BCH-1 has been evaluated. Bioactive compounds were extracted by ethyl acetate and were fractionated by gradient column chromatography from crude extract. Based on FT-IR analysis followed by GC-MS and ESI-MS/MS, the active compound was identified to be Bis-(2-ethylhexyl) phthalate. Antibacterial potential was evaluated by disk diffusion against E. coli (12.33 ± 0.56 mm inhibition zone) and S. aureus (5.66 ± 1.00 mm inhibition zone). Larvicidal potency was performed against Culex quinquefasciatus Say larvae, where Bis-(2-ethylhexyl) phthalate showed 100% mortality at 250 ppm after 72 h with LC50 of 67.03 ppm. Furthermore, after 72 h the acetylcholinesterase inhibition was observed as 29.00, 40.33, 53.00, 64.00, and 75.33 (%) at 50, 100, 150, 200, and 250 ppm, respectively. In comet assay, mean comet tail length (14.18 ± 0.28 μm), tail DNA percent damage (18.23 ± 0.06%), tail movement (14.68 ± 0.56 µm), comet length (20.62 ± 0.64 µm), head length (23.75 ± 0.27 µm), and head DNA percentage (39.19 ± 0.92%) were observed at 250 ppm as compared to the control. The current study for the first time describes the promising antibacterial and larvicidal potential of Bis-(2-ethylhexyl) phthalate from Lactiplantibacillus plantarum that would have potential pharmaceutical applications.

Development of a Reference Method and Materials for Quantitative Measurement of UV-Induced DNA Damage in Mammalian Cells: Comparison of Comet Assay and Cell Viability

Application of DNA damage diagnostic tests is rapidly growing, in particular for ovarian, prostate, and skin cancers; environmental monitoring; chronic and degenerative diseases; and male infertility. Such tests suffer from significant variability among different laboratories due the lack of standardization, experimental validation, and differences in data interpretation. Reference methods and materials for quantitative measurement of UVA-induced DNA damage in mammalian cells are frequently needed. In this study, we examined the use of the single-cell gel electrophoresis (comet) assay to assess the UVA-induced DNA damage in surface-attached Chinese hamster ovary (CHO) cells treated with a photosensitizer as a candidate cellular oxidative damage reference material. We found that the comet images became diffused and the viability of the cells decreased substantially (>20%) as the UVA dose and benzo [a] pyrene (BaP) concentration exceeded 6.3 J/cm2 and 10-6 mol/L BaP. Maintaining the conditions of exposure within this range can improve DNA damage measurement fidelity, particularly if used as a quantitative reference method and to produce materials considered as an in vitro standard for the comet assay.

Reactive oxygen species-dependent upregulation of death receptor, tumor necrosis factor receptor 1, is responsible for theophylline-mediated cytotoxicity in MDA-MB-231 breast cancer cells

Theophylline, a methylxanthine drug, has been used as a therapy for respiratory diseases. Recently, it has also been shown to have a potential in treating different cancers. Also, it has shown promising results in clinical trials for AML in combination therapy. Subsequently, studies have shown theophylline to kill breast cancer cells but not normal breast cells. Therefore, in this study, we have explored the molecular mechanism underlying the cytotoxic effect of theophylline on breast cancer cells. Theophylline-treated cancer cells were analyzed for the transcript and protein expression of candidate apoptotic genes such as TNFR1, caspase-8, -9, -3 using qPCR and immunoblotting, respectively. Cell viability and apoptosis was measured in the presence or absence of TNFR1 inhibitor, R7050, using AO/EtBr staining and MTT assay, respectively. Similarly, oxidative stress was studied by analyzing ROS in the presence or absence of ROS inhibitor, NAC, using DCFDA assay. Theophylline caused reduced cell viability in cancer but not normal cells. Theophylline-treated breast cancer cells showed increased expression of death receptor, TNFR1, along with elevated levels of active caspase-8, -9 and -3. Inhibition of TNFR1 reduced caspase-dependent apoptosis even in the presence of theophylline. Theophylline further caused increased ROS generation, inhibition of which resulted in reduced TNFR1-mediated apoptosis. Theophylline also increased cathepsin activity, which was reduced on exposure of cells to TNFR1 inhibitor, R7050. We conclude that ROS-mediated activation of TNFR1 is responsible for caspase-3 and cathepsin-dependent cell death in breast cancer cells on exposure to theophylline.

Bioaccumulation, release and genotoxicity of stainless steel particles in marine bivalve molluscs

During the decommissioning and removal of radioactive material in nuclear facilities, fine, tritiated dusts of stainless steel, cement or tungsten are generated that could be accidently released to the environment. However, the potential radio- and ecotoxicological effects these tritiated particles may have are unknown. In this study, stainless steel particles (SSPs) representative of those likely to be tritiated are manufactured by hydrogenation and their tissue-specific bioaccumulation, release (depuration) and subsequent genotoxic response have been studied in the marine mussel, Mytilus galloprovincialis, as a baseline for future assessments of the potential effects of tritiated SSPs. Exposure to 1000 μg L^-1 of SSPs and adopting Cr as a proxy for stainless steel revealed relatively rapid accumulation (∼5 h) in the various mussel tissues but mostly in the digestive gland. Over longer periods up to 18 days, SSPs were readily rejected and egested as faecal material. DNA strand breaks, as a measure of genotoxicity, were determined at each time point in mussel haemocytes using single cell gel electrophoresis, or the comet assay. Lack of chemical genotoxicity was attributed to the rapid processing of SSP particles and limited dissolution of elemental components of steel. Further work employing tritiated SSPs will enable radio-toxicology to be studied without the confounding effects of chemical toxicity.

DNA damage in Brazilian newborns admitted to NICUs - association with maternal and neonatal outcomes

Growing evidence suggests that early-life events can predispose the newborn to a variety of health problems in postnatal life, which can lead to the need for specialized care in the neonatal intensive care unit (NICU). These events may be caused by factors intrinsically related to the mother (i.e., lifestyle, socioeconomic conditions), and this interplay between maternal exposure factors and negative outcomes in the neonate can be efficiently monitored through effect biomarkers, such as DNA damage. Thus, the present study aimed to evaluate the DNA damage and the maternal and neonatal factors associated with the genotoxic outcome using newborns admitted to the NICUs of three hospitals located in the extreme south of Brazil. A total of 81 newborns were evaluated. DNA damage was assessed using the comet assay, and according to the result obtained for the evaluated parameters (tail length, % of tail DNA and tail moment). The investigation of associated factors was performed using the bivariate and multivariate Poisson regression analysis. As a result, we observed that the tail moment was the most sensitive parameter to detect differences between variables and genetic outcomes in newborns from NICU. Birthweight and the presence of respiratory diseases were associated with greater risks of DNA damage. Furthermore, the variables family income, sex, head circumference, preterm, birthweight and the presence of respiratory and/or infectious diseases showed a significant statistical difference regarding the groups with and without DNA damage (based on the median of the parameter). While the results of this study will serve as the basis for investigating genetic damage, we encourage that similar studies should be conducted elsewhere in order to confirm these and other outcomes as associated factors with DNA damage in newborns.

Juvenile exposure and adult risk assessment with single versus repeated exposure of melphalan in the germ cells of male SD rat: Deciphering the molecular mechanisms

Melphalan significantly contributes to the increase in childhood cancer survival rate. It acts as a gonadotoxic agent and leads to testes damage, dysbalance in gonadal hormones, and impairment in the germ cell proliferation. Therefore, it might be a potent threat to male fertility in individuals who have undergone melphalan treatment during childhood cancer. However, the molecular mechanisms of melphalan-induced gonadal damage are not yet fully explored and they need to be investigated to determine the benefit-risk profile. In the present study, juvenile male SD rats were subjected to single and intermittent cycles of melphalan exposure in a dose-dependent (0.375, 0.75 and 1.5 mg/kg) manner. Methods of end-points evaluations were quantification of micronuclei formation in peripheral blood, sperm count, sperm motility and head morphology, sperm and testicular DNA damage, histological studies in testes, oxidative/nitrosative stress parameters. A single cycle of exposure at high dose (1.5 mg/kg) produced significant effect on micronuclei formation only after the first week of exposure, whereas failed to produce significant effect at the end of the sixth week. Intermittent cycles of exposure at the dose of 1.5 mg/kg produced significant alterations in all the parameters (micronuclei in peripheral blood, testes and epididymides weight and length, MDA, GSH and nitrite levels, sperm count and motility, sperm head morphology, testicular and sperm DNA damage, protein expression in testes and histological parameters). So, time of exposure as well as the amount of exposure (total dosage administered) is critical in determining the magnitude of the damage in germ cell risk assessment.

Evaluation of Genetic Damage and Antigenotoxic Effect of Ascorbic Acid in Erythrocytes of Orochromis niloticus and Ambystoma mexicanum Using Migration Groups as a Parameter

The comet assay system is an efficient method used to assess DNA damage and repair; however, it currently provides the average result and, unfortunately, the heterogeneity of DNA damage loses relevance. To take advantage of this heterogeneity, migration groups (MGs) of cell comets can be formed. In this study, genetic damage was quantified in erythrocytes of Oreochromis niloticus and Ambystoma mexicanum exposed to ethyl methanesulfonate (ethyl methanesulfonate (EMS) 2.5, 5, and 10 mM over two hours) and ultraviolet C radiation (UV-C) for 5, 10, and 15 min using the tail length, tail moment, and migration group parameters. Additionally, blood cells were exposed to UV-C radiation for 5 min and treated post-treatment at 5, 10, and 15 mM ascorbic acid (AA) for two hours. With the MG parameter, it was possible to observe variations in the magnitude of genetic damage. Our data indicate that MGs help to detect basal and induced genetic damage or damage reduction with approximately the same efficiency of the tail length and tail moment parameters. MGs can be a complementary parameter used to assess DNA integrity in species exposed to mutagens.

Efficacy of ginsenoside Rg3 nanoparticles against Ehrlich solid tumor growth in mice

Solid tumors are fairly common and face many clinical difficulties since they are hardly surgically resectable and broadly do not respond to radiation and chemotherapy. The current study aimed to fabricate ginsenoside Rg3 nanoparticles (Rg3-NPs) and evaluate their antitumor effect against Ehrlich solid tumors (EST) in mice. Rg3-NPs were fabricated using whey protein isolates (WPI), maltodextrin (MD), and gum Arabic (GA). EST was developed by the injection of mice with Ehrlich ascites cells (2.5 × 106). The mice were divided into a control group, EST group, and the EST groups that were treated orally 2 weeks for with normal Rg3 (3 mg/kg b.w.), Rg3-NPs at a low dose (3 mg/kg b.w.), and Rg3-NPs at a high dose (6 mg/kg b.w.). Serum and solid tumors were collected for different assays. The results revealed that synthesized Rg3-NPs showed a spherical shape with an average particle size of 20 nm and zeta potential of -5.58 mV. The in vivo study revealed that EST mice showed a significant increase in AFP, Casp3, TNF-α, MMP-9, VEGF, MDA, and DNA damage accompanied by a significant decrease in SOD and GPx. Treatment with Rg3 or Rg3-NPs decreased the tumor weight and size and induced a significant improvement in all the biochemical parameters. Rg3-NPs were more effective than Rg3, and the improvement was dose-dependent. It could be concluded that fabrication of Rg3-NPs enhanced the protective effect against EST development which may be due to the synergistic effect of Rg3 and MD, GA, and WPI.

Nanoparticled Titanium Dioxide to Remediate Crude Oil Exposure. An In Vivo Approach in Dicentrarchus labrax

The contamination of marine water bodies with petroleum hydrocarbons represents a threat to ecosystems and human health. In addition to the surface slick of crude oil, the water-soluble fraction of petroleum is responsible for the induction of severe toxic effects at different cellular and molecular levels. Some petroleum-derived hydrocarbons are classified as carcinogenic and mutagenic contaminants; therefore, the oil spill into the marine environment can have long term consequences to the biota. Therefore, new tools able to remediate crude oil water accommodation fraction pollution in marine water are highly recommended. Nanomaterials were recently proposed in environmental remediation processes. In the present in vivo study, the efficacy of pure anatase titanium nanoparticles (n-TiO2) was tested on Dicentrarchus labrax exposed to the accommodated fraction of crude oil. It was found that n-TiO2 nano-powders themselves were harmless in terms of DNA primary damage, and the capability of pure anatase n-TiO2 to lower the levels of DNA damage induced by a mixture of genotoxic pollutant was revealed. These preliminary results on a laboratory scale are the prerequisite for deepening this new technology for the abatement of the cellular effects related with oil spill pollutants released in marine environments.

The evaluation of the efficacy and potential genotoxic hazard of combined SAHA and 5-FU treatment in the chemoresistant colorectal cancer cell lines

5-Fluorouracil (5-FU) is an essential chemotherapeutic drug for colorectal cancer (CRC) treatment. However, the frequent development of drug resistance has dramatically affected its clinical use. Therefore, novel treatment strategies are critical to improving patient outcomes. Herein, we investigated the ability of the epigenetic drug SAHA to increase the sensitivity of chemoresistant CRC cells to 5-FU. In addition, we evaluated the potential genotoxic risk of SAHA+5-FU combination treatment. As a model system, we used three CRC cell lines, HT-29, SW480, and HT-29/EGFP/FUR, differing in their resistance to 5-FU. CRC cell lines were exposed to sub-toxic SAHA concentrations for 24 h, followed by a 48 h treatment with 5-FU. The cytotoxicity of SAHA, 5-FU, and SAHA+5-FU was measured by the MTT test, the genotoxicity by the comet assay, and the micronucleus test. The apoptotic/necrotic activity was assessed using morphological criteria. We found a synergic decrease in the viability of HT-29 and SW480 cells, but not the most resistant HT-29/EGFP/FUR cells after combined SAHA+5-FU exposure compared to 5-FU. Remarkably, SAHA most efficiently induced apoptosis in HT-29/EGFP/FUR cells compared to HT-29 and SW480 cells. Combined SAHA+5-FU treatment resulted in a synergistic increase in apoptotic/necrotic cells in HT-29 cell line, while rather additive/sub-additive effect was determined in the SW480 and HT-29/EGFP/FUR cells. At the same time, however, a synergistic rise in micronuclei was found in CRC cell lines (at least at some concentrations). We have shown that SAHA can sensitize CRC cells to 5-FU; therefore, epigenetic and convential drug combinations could be beneficial for the patients. However, the increase in micronucleus formation after combined SAHA+5-FU treatment indicates a potential health hazard. The clastogenic activity could contribute to cancer heterogeneity, favoring progeny of such aberrant cells to clonal expansion. Therefore, developing new specific epigenetic drugs or nanocarriers for targeted drug delivery might reduce the potential genotoxic risk.

HMCES safeguards genome integrity and long-term self-renewal of hematopoietic stem cells during stress responses

Hematopoietic stress drives quiescent hematopoietic stem cells (HSCs) to proliferate, generating reactive oxygen species (ROS) and oxidative DNA damage including abasic sites. Such a coupling between rapid DNA replication and a burst of abasic site formation during HSC stress responses, however, presents a challenge to accurately repair abasic sites located in replication-associated single-stranded DNA. Here we show that HMCES, a novel shield of abasic sites, plays pivotal roles in overcoming this challenge upon HSC activation. While HMCES was dispensable for steady-state hematopoiesis, Hmces-deficient HSCs exhibited compromised long-term self-renewal capacity in response to hematopoietic stress such as myeloablation and transplantation. Loss of HMCES resulted in accumulation of DNA lesions due to impaired resolution of abasic sites generated by activation-induced ROS in activated HSCs and broad downregulation of DNA damage response and repair pathways. Moreover, Hmces-deficient mice died from bone marrow failure after exposure to sublethal irradiation, which also produces ROS. Notably, dysregulation of HMCES occurs frequently in acute lymphocytic leukemia (ALL) and is associated with poor clinical outcomes. Together, our findings not only highlighted HMCES as a novel genome protector in activated HSCs, but also position it as a potential selective target against ALL while sparing normal hematopoiesis.

An integrated approach for chemical water quality assessment of an urban river stretch through Effect-Based Methods and emerging pollutants analysis with a focus on genotoxicity

The impact of emerging chemical pollutants, on both status and functionality of aquatic ecosystems is worldwide recognized as a relevant issue of concern that should be assessed and managed by researchers, policymakers, and all relevant stakeholders. In Europe, the Reach Regulation has registered more than 100.000 chemical substances daily released in the environment. Furthermore, the effects related to the mixture of substances present in aquatic ecosystems may not be predictable on the basis of chemical analyses alone. This evidence, coupled with the dramatic effects of climate changes on water resources through water scarcity and flooding, makes urgent the application of innovative, fast and reliable monitoring methods. In this context, Effect-Based Methods (EBMs) have been applied in the urban stretch of the Tiber River (Central Italy) with the aim of understanding if detrimental pressures affect aquatic environmental health. In particular, different eco-genotoxicological assays have been used in order to detect genotoxic activity of chemicals present in the river, concurrently characterized by chemical analysis. Teratogenicity and embryo-toxicity have been studied in order to cover additional endpoints. The EBMs have highlighted the presence of diffuse chemical pollution and ecotoxicological effects in the three sampling stations, genotoxicological effects have been also detected through the use of different tests and organisms. The chemical analyses confirmed that in the aquatic ecosystems there is a diffuse presence, even at low concentrations, of emerging contaminants such as pharmaceuticals, not routinely monitored pesticides, personal care products, PFAS. The results of this study can help to identify an appropriate battery of EBMs for future studies and the application of more appropriate measures in order to monitor, mitigate or eliminate chemical contamination and remediate its adverse/detrimental effects on the ecosystem health.

Modifying effects of menthol against benzo(a)pyrene-induced forestomach carcinogenesis in female Swiss mice

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon widespread in the environment and closely associated to tobacco use, which is an important risk factor for highly incident stomach cancer. Menthol, a monoterpene extracted from Mentha genus species, has multiple biological properties, including anti-inflammatory and gastroprotective properties, but its effects on carcinogenesis are still to be fully understood. Thus, we evaluated the modifying effects of Ment against BaP-induced forestomach carcinogenesis. Female Swiss mice received BaP by intragastrical (i.g.) administration (50 mg/kg of body weight [b wt], 2×/week), from weeks 1-5 weeks. Concomitantly, mice received Menthol at 25 (Ment25) or 50 (Ment50) mg/kg b wt (i.g, 3×/week). Animals were euthanized at weeks 5 (n = 5 mice/group) or 30 (n = 10 mice/group). At week 5, both Ment doses reduced peripheral leukocyte blood genotoxicity 4 h after the last BaP administration, but only Ment50 attenuated this biomarker 8 h after the last BaP administration. In accordance to these findings, both Ment interventions attenuated BaP-induced increase in the percentage of H2A.X-positive forestomach epithelial cells. Moreover, Ment50 reduced cell proliferation and apoptosis (i.e., Ki-67 and caspase-3, respectively) in forestomach epithelium but exerted no significant effects on NFκB, and Nrf2 protein levels. At week 30, Ment50 reduced by ~55% the incidence of BaP-induced forestomach diffuse hyperplasia and multiplicity of forestomach tumors (squamous cell papillomas and carcinomas). Our findings indicate that Ment50, administered during initiation phase, attenuates forestomach carcinogenesis by reducing early genotoxicity, cell proliferation, and apoptosis induced by BaP.

Comparison of Estrogenic, Spectroscopic, and Toxicological Analyses of Pilot-Scale Water, Wastewaters, and Processed Wastewaters at Select Military Installations

Reuse of water requires the removal of contaminants to ensure human health. We report the relative estrogenic activity (REA) of reuse treatment design scenarios for water, wastewaters, and processed wastewaters before and after pilot-scale treatment systems tested at select military facilities. The comparative relationships between REA, several composite toxicological endpoints, and spectroscopic indicators were evaluated for different reuse treatment trains. Four treatment processes including conventional and advanced treatments reduced the estrogenicity by at least 33%. Biologically based methods reduced estrogenicity to below detection levels. Conventional treatment scenarios led to significantly less reduction of adverse biological endpoints compared to the advanced treatment scenarios. Incorporating the anaerobic membrane bioreactor reduced more endpoints with higher reduction percentages compared to the sequencing batch reactor design. Membrane technology and advanced oxidation generated reductions across all biological endpoints, from 65% (genotoxicity) to 100% (estrogenicity). The design scenarios featuring a low-cutoff mechanical screen filter, intermittent activated carbon biofilter, and membrane filtration achieved the highest percent reduction and produced water with the lowest negative biological endpoints. Spectroscopic indicators demonstrated case-specific relationships with estrogenicity and toxicity. Estrogenicity consistently correlated with cytotoxicity and thiol reactivity, indicating the potential for preliminary estrogenicity screening using thiol reactivity.

Cellular Responses Induced by Zinc in Zebra Mussel Haemocytes. Loss of DNA Integrity as a Cellular Mechanism to Evaluate the Suitability of Nanocellulose-Based Materials in Nanoremediation

Zinc environmental levels are increasing due to human activities, posing a threat to ecosystems and human health. Therefore, new tools able to remediate Zn contamination in freshwater are highly recommended. Specimens of Dreissena polymorpha (zebra mussel) were exposed for 48 h and 7 days to a wide range of ZnCl2 nominal concentrations (1-10-50-100 mg/L), including those environmentally relevant. Cellulose-based nanosponges (CNS) were also tested to assess their safety and suitability for Zn removal from freshwater. Zebra mussels were exposed to 50 mg/L ZnCl2 alone or incubated with 1.25 g/L of CNS (2 h) and then removed by filtration. The effect of Zn decontamination induced by CNS has been verified by the acute toxicity bioassay Microtox®. DNA primary damage was investigated by the Comet assay; micronuclei frequency and nuclear morphological alterations were assessed by Cytome assay in mussels' haemocytes. The results confirmed the genotoxic effect of ZnCl2 in zebra mussel haemocytes at 48 h and 7-day exposure time. Zinc concentrations were measured in CNS, suggesting that cellulose-based nanosponges were able to remove Zn(II) by reducing its levels in exposure waters and soft tissues of D. polymorpha in agreement with the observed restoration of genetic damage exerted by zinc exposure alone.

Use of the alkaline comet assay for monitoring genotoxic effects of arsenic in human populations

The alkaline comet assay has been widely used to determine genotoxicity in human populations exposed to arsenic. The sample sizes of earlier studies were usually small, and inconsistent results were found. Meta-analyses can merge the results of multiple studies of the same type and increase the credibility of the conclusion by increasing the sample size. Thus, to investigate the monitoring effect of alkaline comet assay on genotoxicity for arsenic exposed population, meta-analyses were performed. Thirteen studies were found to meet the inclusion criteria and were included in this study; of them, twelve articles were of medium quality (15-20 points), only one study was of high quality (21-27 points). Meta-analyses showed that the overall estimates of Mean Ratio (MR, defined as the mean value of the response in the exposed group divided by that in the reference group) were 2.81(95 % confidence interval (CI) 1.93-4.10); 2.37(95 % CI, 1.73-3.26), and 1.69(95 %CI, 1.29-2.20) for comet tail length, % tail DNA, and tail moment, respectively. This shows that the level of DNA damage in arsenic exposed population is significantly higher than that in control populations. A meta-analysis of the correlation coefficients showed that the overall estimate was 0.52 (95 %CI, 0.48∼0.56, P<0.05) with all correlation coefficients included, but it changed to 0.24 (95 %CI, 0.17∼0.28, P<0.05) when two abnormal correlation coefficients were excluded, suggesting there was a positive correlation between arsenic load in vivo and DNA damage, but the overall estimate value of coefficients was unstable. Therefore, we conclude that the alkaline comet assay can be used as an effective genotoxic biomonitoring tool for arsenic-exposed populations. However, more and higher-quality studies are still needed to verify its actual application value.