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The assessment of mutagenicity is essential in drug discovery, as it may lead to cancer and germ cells damage. Although in silico methods have been proposed for mutagenicity prediction, their performance is hindered by the scarcity of labeled molecules. However, experimental mutagenicity testing can be time-consuming and costly. One solution to reduce the annotation cost is active learning, where the algorithm actively selects the most valuable molecules from a vast chemical space and presents them to the oracle (e.g., a human expert) for annotation, thereby rapidly improving the model's predictive performance with a smaller annotation cost. In this paper, we propose muTOX-AL, a deep active learning framework, which can actively explore the chemical space and identify the most valuable molecules, resulting in competitive performance with a small number of labeled samples. The experimental results show that, compared to the random sampling strategy, muTOX-AL can reduce the number of training molecules by about 57%. Additionally, muTOX-AL exhibits outstanding molecular structural discriminability, allowing it to pick molecules with high structural similarity but opposite properties. An active learning model, muTOX-AL, has been proposed for the task of molecular mutagenicity prediction. muTOX-AL is capable of rapidly enhancing its performance with a small number of labeled samples, thereby reducing experimental costs. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate all studies which used the micronucleus assay using oral cells in the attempt to understand whether such technique is efficient in evaluating genotoxicity in gas station attendants. Full manuscripts from 16 studies were carefully selected by the authors. Our results demonstrate that continuous exposure to derivatives of petroleum may lead to genotoxic effects since all studies demonstrated positive findings (16 out of 16) and 11 of them had a strong or moderate final rating. In summary, our results reveal that gas station attendants are occupationally exposed to genotoxic agents and that the micronucleus assay in oral mucosa is indeed an effective method to evaluate genotoxicity in this specific case. Such findings are very important for protecting these professionals who are continuously exposed to chemicals for long periods. [ABSTRACT FROM AUTHOR]

Multiple Wolbachia strains can block pathogen infection, replication and/or transmission in Aedes aegypti mosquitoes under both laboratory and field conditions. However, Wolbachia effects on pathogens can be highly variable across systems and the factors governing this variability are not well understood. It is increasingly clear that the mosquito host is not a passive player in which Wolbachia governs pathogen transmission phenotypes; rather, the genetics of the host can significantly modulate Wolbachia‐mediated pathogen blocking. Specifically, previous work linked variation in Wolbachia pathogen blocking to polymorphisms in the mosquito alpha‐mannosidase‐2 (αMan2) gene. Here we use CRISPR‐Cas9 mutagenesis to functionally test this association. We developed αMan2 knockouts and examined effects on both Wolbachia and virus levels, using dengue virus (DENV; Flaviviridae) and Mayaro virus (MAYV; Togaviridae). Wolbachia titres were significantly elevated in αMan2 knockout (KO) mosquitoes, but there were complex interactions with virus infection and replication. In Wolbachia‐uninfected mosquitoes, the αMan2 KO mutation was associated with decreased DENV titres, but in a Wolbachia‐infected background, the αMan2 KO mutation significantly increased virus titres. In contrast, the αMan2 KO mutation significantly increased MAYV replication in Wolbachia‐uninfected mosquitoes and did not affect Wolbachia‐mediated virus blocking. These results demonstrate that αMan2 modulates arbovirus infection in A. aegypti mosquitoes in a pathogen‐ and Wolbachia‐specific manner, and that Wolbachia‐mediated pathogen blocking is a complex phenotype dependent on the mosquito host genotype and the pathogen. These results have a significant impact for the design and use of Wolbachia‐based strategies to control vector‐borne pathogens. [ABSTRACT FROM AUTHOR]

Traditional textile dyeing processes usually require large quantities of water and energy and generate wastewater that can be harmful to the environment. Dyeing in supercritical carbon dioxide (sc‐CO2) media is promising in textile coloration due especially to it providing a waterless process and eliminating the need for an energy intensive drying step. The natural anthraquinone emodin showed promising results for dyeing different fibres through sc‐CO2 process. However, emodin is mutagenic. The aim of this study was to develop non‐mutagenic derivatives of emodin that can be applied to textiles using sc‐CO2. Emodin structure was modified incorporating acryloyl groups, which are considered suitable for decreasing potential for DNA intercalation, and thus mutagenicity. The presence of acryloyl groups would also enable atmospheric plasma induced bonding with fibres. Molecular modelling studies showed that emodin derivatives became less planar with increasing number of attached acryloyl groups, making intercalation unlikely. The derivatives produced were tested to assess mutagenicity in vitro (Salmonella/microsome assay, TA1537, 10% S9) and in vivo (micronucleus test in hemocytes of aquatic crustacean). We found that emodin can be derivatised using acryloyl chlorides to give mono‐ and di‐acrylate esters suitable for dyeing polyester fibres in sc‐CO2. However, the new dyes presented mutagenicity for both in vitro and in vivo. Although the derivatives provided greenish‐yellow alternatives to emodin for dyeing synthetic fibres, they do not appear to be viable alternatives from the point of view of preserving human and environmental health. Plasma bonding studies are underway. [ABSTRACT FROM AUTHOR]

INTRODUCTION: Electronic cigarettes (e-cigarettes) are often advertised as a safer alternative to traditional smoking. However, recent data suggest they may not be as safe as previously believed. This study aims to evaluate the genotoxicity and mutagenicity of e-cigarette liquids. METHODS: We randomly selected eight varieties of e-cigarette liquids from the local market in Jeddah, Saudi Arabia. We evaluated their genotoxicity using the Genotoxicity SOS-Chromo Test™ Kit. In this investigation, a rat liver S9 fraction was utilized to emulate liver metabolic function to measure any chemical substance's mutagenic potential. The SOS-Chromo Test was performed by recording the β-galactosidase and alkaline phosphatase activity with and without the metabolic activation enzyme (S-9). RESULTS: All samples, except for the first two dilutions of sample 2, were nongenotoxic in the absence of the S9 activation enzyme, according to the genotoxicity analysis. However, when tested in the presence of the S9 enzyme, samples 2, 4, and 7 exhibited mutagenic activity at varying concentrations. CONCLUSION: Contrary to common belief, e-cigarettes are not safe. The present investigation confirms the presence of both toxicants and carcinogens in some e-cigarette liquids. This exposure could increase users' risk of various health complications. [ABSTRACT FROM AUTHOR]

Sodium acetate (NaA) and sodium sulfite (NaS) are two food additives in the class of preservatives. In this study, 3-(4,5-dimethyl thiazolyl-2)-2,5 diphenyltetrazolium bromide (MTT) assay was established to detect the cytotoxicity, and comet assay was used to determine the genotoxicity of NaA and NaS. For the MTT assay, human hepatocellular carcinoma (HepG2) cells were treated with different concentrations of each preservative (15.63, 31.25, 62.50, 125, 250, 500, 1000 and 2000 μg/mL for NaA; 3.91, 7.81, 15.62, 31.25, 62.50, 125, 250 and 500 μg/mL for NaS, respectively) for 24-h. non-treated wells used as control (only medium) were included. Comet assay was performed on lymphocytes isolated from healthy donors with multiple concentrations of NaA (15.63, 31.25, 62.50, 125, 250 μg/mL) and NaS (3.91, 7.81, 15.62, 31.25, 62.50 μg/mL) for 1 h. A negative (distilled water) and a positive control (100 μM H2O2) were also included. Significant cytotoxic activity was detected for NaA and NaS only at the highest concentration. Besides, both substances significantly increased DNA damage compared to the control at almost all concentrations (except at low concentrations). In general, both food preservatives exhibited weak cytotoxic effects in HepG2 cells. These food preservatives showed genotoxic activity, especially at higher concentrations. [ABSTRACT FROM AUTHOR]

Resin‐based three‐dimensional (3D) printing finds extensive application in the field of dentistry. Although studies of cytotoxicity, mechanical and physical properties have been conducted for newly released 3D printing resins such as Crowntec (Saremco), Temporary Crown Resin (Formlabs) and Crown & Bridge (Nextdent), the resistance of these materials to esterases in saliva has not been demonstrated at the molecular level. Therefore, in this study, the binding affinities and stability of these new 3D printing resins to the catalytic sites of esterases were investigated using molecular docking and molecular mechanics with Poisson–Bolzmann and surface area solvation (MM/PBSA) methods after active pocket screening. Toxicity predictions of the materials were also performed using ProTox‐II and Toxtree servers. The materials were analyzed for mutagenicity, cytotoxicity, and carcinogenicity, and LD50 values were predicted from their molecular structures. The results indicated that out of the three novel 3D printing materials, Nexdent exhibited reduced binding affinity to esterases, indicating enhanced resistance to enzymatic degradation and possessing a superior toxicity profile. [ABSTRACT FROM AUTHOR]

Atmospheric nonthermal plasma (ANTP) has rapidly evolved as an innovative tool in biomedicine with various applications, especially in treating skin diseases. In particular, the formation of reactive oxygen species (ROS) and nitrogen species (RNS), which are generated by ANTP, plays an important role in the biological signaling pathways of human cells. Unfortunately, excessive amounts of these reactive species significantly result in cellular damage and cell death induction. To ensure the safe application of ANTP, preclinical in vitro studies must be conducted before proceeding to in vivo or clinical trials involving humans. Our study aimed to investigate adverse effects on genetic substances in murine fibroblast cells exposed to ANTP. Cell viability and proliferation were markedly reduced after exposing the cells with plasma. Both extracellular and intracellular reactive species, especially RNS, were significantly increased upon plasma exposure in the culture medium and the cells. Notably, significant DNA damage in the cells was observed in the cells exposed to plasma. However, plasma was not classified as a mutagen in the Ames test. This suggested that plasma led to the generation of both extracellular and intracellular reactive species, particularly nitrogen species, which affect cell proliferation and are also known to induce genetic damage in fibroblast cells. These results highlight the genotoxic and mutagenic effects of ANTP, emphasizing the need for the cautious selection of plasma intensity in specific applications to avoid adverse side effects resulting from reactive species production. [ABSTRACT FROM AUTHOR]

Human liver-derived metabolically competent HepaRG cells have been successfully employed in both two-dimensional (2D) and 3D spheroid formats for performing the comet assay and micronucleus (MN) assay. In the present study, we have investigated expanding the genotoxicity endpoints evaluated in HepaRG cells by detecting mutagenesis using two error-corrected next generation sequencing (ecNGS) technologies, Duplex Sequencing (DS) and High-Fidelity (HiFi) Sequencing. Both HepaRG 2D cells and 3D spheroids were exposed for 72 h to N-nitrosodimethylamine (NDMA), followed by an additional incubation for the fixation of induced mutations. NDMA-induced DNA damage, chromosomal damage, and mutagenesis were determined using the comet assay, MN assay, and ecNGS, respectively. The 72-h treatment with NDMA resulted in concentration-dependent increases in cytotoxicity, DNA damage, MN formation, and mutation frequency in both 2D and 3D cultures, with greater responses observed in the 3D spheroids compared to 2D cells. The mutational spectrum analysis showed that NDMA induced predominantly A:T → G:C transitions, along with a lower frequency of G:C → A:T transitions, and exhibited a different trinucleotide signature relative to the negative control. These results demonstrate that the HepaRG 2D cells and 3D spheroid models can be used for mutagenesis assessment using both DS and HiFi Sequencing, with the caveat that severe cytotoxic concentrations should be avoided when conducting DS. With further validation, the HepaRG 2D/3D system may become a powerful human-based metabolically competent platform for genotoxicity testing. [ABSTRACT FROM AUTHOR]

Cyanides and nitriles, characterized by their R-CN chains, are known for their toxicity, mutagenicity, and carcinogenicity, posing significant threats to environmental and human health. This study aims to explore the biodegradation capabilities of Rhodococcus sp. in breaking down cyanide and nitrile bonds. Rhodococcus pyridinivorans strain I-benzo was isolated from tanning waste and cultured in mineral media with a 20 mM benzonitrile substrate. The activity of this strain was tested using substrates such as benzonitrile, acetonitrile, acrylonitrile, benzamide, acetamide, and acrylamide, revealing positive reactions of nitrile hydratase and amidase enzymes through the Nessler measurement method, which indicated the production of ammonia and carboxylic acids. Furthermore, the degradation tests showed that the Vmax values for the biodegradation of potassium cyanide and sodium cyanide were 0.56 ppm/minute and 0.21 ppm/minute, respectively. These findings highlight the potential application of Rhodococcus pyridinivorans strain I-benzo in mitigating the environmental impact of cyanide and nitrile pollutants through efficient biodegradation. [ABSTRACT FROM AUTHOR]

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Deucravacitinib, SOTYKTU was approved recently in the year 2022 to treat psoriasis. The present work attempts to identify and characterize degradation products formed when the drug is exposed to hydrolytic, oxidative, thermal, and photolytic stress conditions as well as to study the kinetics of the drug's degradation under various stress conditions. A high‐performance liquid chromatography method was developed for the separation of deucravacitinib and its degradation product comprising mobile phase of ammonium acetate (pH 4.75) buffer as solvent A and acetonitrile as solvent B and Phenomenex Gemini, C‐18 (250 × 4.6 mm, 5µ) column as stationary phase. Injection volume, flow rate, and detection wavelength for the method were optimized as 10 µL, 1.0 mL/min, and 254 nm, respectively. Accuracy, precision, linearity, robustness, and selectivity were found to be acceptable when validated in the concentration range between 5 and 150 µg/mL of deucravacitinib. The structure of the degradation product was characterized using liquid chromatography‐tandem mass spectrometry which shows a protonated molecular ion peak at m/z 358.1805 in the electrospray ionization positive mode. In silico mutagenicity tests yielded positive results for deucravacitinib and its degradation product, triggering an alarm for mutagenicity for both structures, whereas in silico toxicity studies did not generate any structural alerts. [ABSTRACT FROM AUTHOR]

The current Organisation for Economic Co-Operation and Development test guideline number 487 (OECD TG No. 487) provides instruction on how to conduct the in vitro micronucleus assay. This assay is one of the gold standard approaches for measuring the mutagenicity of test items; however, it is directed at testing low molecular weight molecules and may not be appropriate for particulate materials (e.g. engineered nanoparticles [ENPs]). This study aimed to adapt the in vitro micronucleus assay for ENP testing and underpins the development of an OECD guidance document. A harmonized, nano-specific protocol was generated and evaluated by two independent laboratories. Cell lines utilized were human lymphoblastoid (TK6) cells, human liver hepatocytes (HepG2) cells, Chinese hamster lung fibroblast (V79) cells, whole blood, and buffy coat cells from healthy human volunteers. These cells were exposed to reference ENPs from the Joint Research Council (JRC): SiO2 (RLS-0102), Au5nm and Au30nm (RLS-03, RLS-010), CeO2 (NM212), and BaSO4 (NM220). Tungsten carbide-cobalt (WC/Co) was used as a trial particulate positive control. The chemical controls were positive in all cell cultures, but WC/Co was only positive in TK6 and buffy coat cells. In TK6 cells, mutagenicity was observed for SiO2- and both Au types. In HepG2 cells, Au5nm and SiO2 showed sub-two-fold increases in micronuclei. In V79 cells, whole blood, and buffy coat cells, no genotoxicity was detected with the test materials. The data confirmed that ENPs could be tested with the harmonized protocol, additionally, concordant data were observed across the two laboratories with V79 cells. WC/Co may be a suitable particulate positive control in the in vitro micronucleus assay when using TK6 and buffy coat cells. Detailed recommendations are therefore provided to adapt OECD TG No. 487 for testing ENP. [ABSTRACT FROM AUTHOR]

Simple Summary: The dramatic improvement in the prognosis of patients with advanced epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) became possible thanks to the advent of EGFR-tyrosine kinase inhibitors (EGFR-TKIs). In a subgroup of EGFR mutations, known as uncommon (ucEGFRmuts) and rare, NSCLC-mutated patients show, most of the time, lower EGFR-TKIs sensitivity than most common mutations, making this a great clinical point of discussion. Here, we summarized recent data about EGFR exon 20 insertion-positive NSCLC patients and Phase 3 trials ongoing, with a specific focus on the PAPILLON study. Uncommon (ucEGFRmuts) and rare epidermal growth factor receptor (EGFR) mutations account for 10–15% of diagnosed cases and consist of a heterogeneous group represented by several clusters within exons 18–21 (e.g., exon 18 point mutations, exon 21 L861X, exon 20 S768I), as well as exon 20 insertions (Ex20ins). Their incidence is under molecular and clinical investigation following recent findings that reported an increase of sensitivity and specificity of next-generation sequencing (NGS) methods. Consequently, their detection allows for the selection of emerging treatment options to significantly improve patients' outcomes in these particular subgroups of EGFR-mutated advanced non-small cell lung cancer (NSCLC). Specifically, this commentary is focused on the notable progress of the Phase 3 PAPILLON study that showed primary efficacy results from amivantamab, a bispecific antibody with specific binding and affinity to extracellular domains of EGFR and MET, plus chemotherapy in the first-line setting for EGFR exon 20 insertion–mutated advanced or metastatic NSCLC patients, as compared with chemotherapy alone, thus becoming the new standard of care in this group of patients. [ABSTRACT FROM AUTHOR]

The robust control of genotoxic N -nitrosamine (NA) impurities is an important safety consideration for the pharmaceutical industry, especially considering recent drug product withdrawals. NAs belong to the 'cohort of concern' list of genotoxic impurities (ICH M7) because of the mutagenic and carcinogenic potency of this chemical class. In addition, regulatory concerns exist regarding the capacity of the Ames test to predict the carcinogenic potential of NAs because of historically discordant results. The reasons postulated to explain these discordant data generally point to aspects of Ames test study design. These include vehicle solvent choice, liver S9 species, bacterial strain, compound concentration, and use of pre-incubation versus plate incorporation methods. Many of these concerns have their roots in historical data generated prior to the harmonization of Ames test guidelines. Therefore, we investigated various Ames test assay parameters and used qualitative analysis and quantitative benchmark dose modelling to identify which combinations provided the most sensitive conditions in terms of mutagenic potency. Two alkyl-nitrosamines, N -nitrosodimethylamine (NDMA) and N -nitrosodiethylamine (NDEA) were studied. NDMA and NDEA mutagenicity was readily detected in the Ames test and key assay parameters were identified that contributed to assay sensitivity rankings. The pre-incubation method (30-min incubation), appropriate vehicle (water or methanol), and hamster-induced liver S9, alongside Salmonella typhimurium strains TA100 and TA1535 and Escherichia coli strain WP2uvrA(pKM101) provide the most sensitive combination of assay parameters in terms of NDMA and NDEA mutagenic potency in the Ames test. Using these parameters and further quantitative benchmark dose modelling, we show that N -nitrosomethylethylamine (NMEA) is positive in Ames test and therefore should no longer be considered a historically discordant NA. The results presented herein define a sensitive Ames test design that can be deployed for the assessment of NAs to support robust impurity qualifications. [ABSTRACT FROM AUTHOR]

Based on the data of 2254 daily meteorological stations in China from 1961 to 2021, this study calculated the standardized precipitation evapotranspiration index (SPEI) of the national multi-time scale by using the FAO Penman–Monteith model to quantify the changes in dry and wet conditions. The Mann–Kendall mutation test, wavelet analysis, and other methods were used to study the spatial pattern and temporal evolution of drought. The results showed: (1) In the past 61 years, there were obvious spatial and temporal differences in drought in China, and the interannual variation in drought severity in SPEI-1, SPEI-3, and SPEI-12 gradually decreased at a rate of 0.005/10a, 0.021/10a, and 0.092/10a, respectively. (2) The time point of dry and wet mutation was 1989 according to the MK mutagenicity test. (3) Wavelet analysis showed that the drought cycle on the annual scale and the seasonal scale was consistent, and the main period was about 30 years. (4) In the past 61 years, the drought intensity of different degrees in China has shown a weakening trend, and the drought intensity reached the highest value in 61 years in 1978, at 1836.42. In 2020, the drought intensity was the lowest, at 261.55. (5) The proportion of drought stations has shown a decreasing trend. The proportion of drought-free stations has fluctuated greatly, ranging from 42.12% to 89.25%, with 2020 being the highest. This study provides a scientific basis for further research on the causes and coping strategies of drought and is of great significance for strengthening China's drought monitoring, early warning ,and adaptation capabilities. [ABSTRACT FROM AUTHOR]

Featured Application: This review evaluates the potential of date seed coffee as a sustainable and caffeine-free alternative to traditional coffee. The authors propose an environmentally friendly approach to beverage production by utilizing discarded date seeds. The findings provide comprehensive evidence supporting the safe consumption of date seed coffee, as demonstrated by a thorough toxicological risk assessment. This application aims to reduce waste and introduce a new culinary use for date seeds, providing a distinctive flavor profile and potential health benefits to the European market. Approximately 8 million tons of dates (Phoenix dactylifera) are produced globally each year. The seeds of the fruit, which make up 10–15% of its weight, are typically discarded. Date seed coffee is a sustainable food system innovation rooted in the traditions of high date-producing regions. Dating back to the late 19th century, date seed coffee has evolved from a historical coffee substitute to a modern caffeine-free alternative. Date seed coffee has a long history of consumption in the European Union (EU). This indicates that it may not require novel food authorization. The composition of date seeds is evaluated in this review and a toxicological risk assessment for date seed coffee is conducted. Subchronic studies show that consuming date seed or date seed coffee has no adverse effects. Therefore, currently unavailable chronic toxicity, carcinogenicity, and reproductive toxicity studies may be unnecessary. However, for a comprehensive evaluation, it is recommended to conduct an in vitro mutagenicity test. This review provides information on the safety of date seed coffee and highlights the need for further research. [ABSTRACT FROM AUTHOR]

Introduction: Health care workers handling antineoplastic drugs (ADs) are at risk of carcinogenic, mutagenic and reproductive toxic risks (CMR). The aim of this study was to assess the impact of the lack of knowledge (K) on risk perception (P) and on protective practices (PP) related to the handling of home-based chemotherapy (HC) by home nurses. Methods: This study was conducted in Normandy among home nurses. A questionnaire was developed to explore the K, P and PP related to handling ADs by home nurses working with four different providers from two hospitals. Results: Among the 28 home nurses included, 25.93% had received initial training on the specific treatment of ADs, 48.15% scored below average on risk management K, 52.00% scored below average on personal PP. Conclusion: This study reveals the importance of adapted and regular training on the handling of ADs. It will help develop a climate of safety and reinforce adherence to wearing personal protective equipment to protect health care workers from contamination. [ABSTRACT FROM AUTHOR]

Background: Zingiber zerumbet (L.) Smith (lempoyang) has a traditional application in the treatment of indigestion, worm infestation, loss of appetite, and postpartum conditions. Objectives: Extracts of Z. zerumbet (methanol, hexane, and ethyl acetate) were utilized to investigate the mutagenic, anti-mutagenic, and cytotoxic properties. Materials and Methods: Initially, a mutagenicity test (Ames test) was conducted, followed by an anti-mutagenicity test, to assess the potential of Z. zerumbet extracts in inhibiting mutagenicity induced by sodium azide and 9-aminoacridine. Furthermore, the cytotoxic ability of the extracts was evaluated using the methyl thiazolyl tetrazolium (MTT) assay. Results: The mutagenicity assessment revealed that the methanol extract of Z. zerumbet exhibited a twofold increase in the number of revertants in Salmonella typhimurium strain TA 1537. Similar results were observed for the hexane extract, except at a concentration of 6.25 mg/mL, where no significant increase in revertants was observed. On the other hand, the ethyl acetate extract demonstrated a twofold increase in revertants in S. typhimurium strain TA 1535. Notably, the ethyl acetate extract displayed remarkable anti-mutagenic activity against 9-aminoacridine, while the hexane extract exhibited strong anti-mutagenic activity against sodium azide. Regarding cytotoxicity assessment using the MTT assay, the methanol extract of Z. zerumbet exhibited the highest cytotoxicity with an IC50 value estimated at 388.50 ± 135.75 µg/mL. The hexane and ethyl acetate extracts showed IC50 values of 514.17 ± 135.75 and 589.67 ± 241.67 µg/mL, respectively. Conclusion: The extracts displayed both mutagenic and cytotoxic activities. However, they also exhibited promising anti-mutagenic potential, which could be harnessed for cancer prevention purposes. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the scientific literature on the micronucleus assay in nasal mucosa as an appropriate method for evaluating genotoxicity caused by chemical agents. According to the PRISMA guidelines, only in vivo human studies with micronucleus assays using nasal cells were considered. Reviews, case reports, editorials, letters to the editor, and articles not written in English were excluded. The following scientific databases/search engines were used: PubMed/MEDLINE, Scopus, and Web of Science. Results: This review included 13 studies. Four articles detected no statistical significance regarding the frequency of micronuclei while nine articles showed an increase in micronuclei in nasal cells. In the qualitative analysis, two articles were considered strong, eight were moderate and three were weak. The micronucleus assay using nasal mucosa cells is a sensitive and effective technique for assessing DNA damage and an appropriate method for monitoring humans continuously exposed to chemicals. [ABSTRACT FROM AUTHOR]

The goal of this study was to perform systematic review (SR) to investigate the scientific literature regarding the genotoxicity effects of fluoride exposure (FE). The search of databases used for this study was PubMed/Medline, SCOPUS and Web of Science. The quality of included studies was assessed using the EPHPP (Effective Public Health Practice Project). A total of 20 potentially relevant studies were selected for evaluating the genotoxicity induced by fluoride. Few studies have revealed that FE induces genotoxicity. A total of 14 studies demonstrated negative results whereas 6 studies did not. After reviewing the twenty studies, 1 was classified as weak, 10 were considered moderate and 9 were considered strong, according to the EPHPP. Taken together, it has been established that genotoxicity of fluoride is limited. [ABSTRACT FROM AUTHOR]

Selenium is an essential multifunctional trace element in diverse organisms. The only Se-glycosyltransferase identified that catalyzes the incorporation of selenium in selenoneine biosynthesis is SenB from Variovorax paradoxus. Although the biochemical function of SenB has been investigated, its substrate specificity, structure, and catalytic mechanism have not been elucidated. Here, we reveal that SenB exhibits sugar donor promiscuity and can utilize six UDP-sugars to generate selenosugars. We report crystal structures of SenB complexed with different UDP-sugars. The key elements N20/T23/E231 contribute to the sugar donor selectivity of SenB. A proposed catalytic mechanism is tested by structure-guided mutagenesis, revealing that SenB yields selenosugars by forming C-Se glycosidic bonds via spontaneous deprotonation and disrupting Se-P bonds by nucleophilic water attack, which is initiated by the critical residue K158. Furthermore, we functionally and structurally characterize two other Se-glycosyltransferases, CbSenB from Comamonadaceae bacterium and RsSenB from Ramlibacter sp., which also exhibit sugar donor promiscuity. SenB is a Se-glycosyltransferase in the microbial biosynthesis pathway of selenoneine. Here, the authors perform the structure-function investigation, providing mechanistic insights into a two-step catalytic reaction of SenB. [ABSTRACT FROM AUTHOR]

Background: Methanolic and chloroformic extract of Achillea millefolium and Chaerophyllum villosum were evaluated for HPLC analysis, genotoxic and antioxidant potential. Materials and methods: Genotoxic activity was carried out on human blood lymphocytes via comet assay and antioxidant activity was studied through DPPH method. Results: The genotoxic potential of A. millefolium and C. villosum's methanolic and chloroformic extract was analysed using comet assay technique. Comet shaped human lymphocytes cells were observed when treated with different concentrations (50 mg/mL, 75 mg/mL, 100 mg/mL) of methanolic and chloroformic extract of both plants. Reading was taken on the basis of damaged DNA head and tail length. Greater the length of tail as compared to head, greater will be the damage and vice versa. Total comet score was obtained from A. millefolium subjected to different concentrations. After a time interval of 24 h both the extract showed dose dependant genoprotection with maximum genoprotectivity at 98.7 ± 12.7 and 116 ± 5.3 at 50 mg/100 mL for methanolic and chloroformic extract respectively. Similarly Total Comet score was obtained from C. villosum subjected to different concentrations of methanolic and chloroformic extract. After 24 h exhibited dose dependent genoprotection with maximum protectivity at 85.7 ± 22.0 and 101.7 ± 8.6 at 50 mg/100 mL for methanolic and chloroformic extract were determined. The antioxidant activity revealed that methanolic extract of A. millefolium showed highest antioxidant activity (84.21%) at 300 mg/ml after 90 min while the chloroformic extract of C. villosum exhibited highest (68.46%) antioxidant activity (59.69%) at 300 µg/ml after 90 min but less than the standard drug ascorbic acid (88.72%). Quantitative phytochemical screening revealed high percentage of alkaloids (27.4%), Phenols (34.5%), Flavonoids (32.4%) as compared to Tannins (12%) in methanolic extract of A.millefolium. While high percentage of alkaloids (31.4), Phenols (19.3%), Flavonoids (35.5%) as compared to Tannins (16.6%) in chloroformic extract of C. villosum. Conclusion: The present results showed that A. millefolium and C. villosum possess a number of important compounds and revealed genoprotective property which may be used to treat several genetic disorders such as alzeimer's disease in future (Grodzicki W, Dziendzikowska K, Antioxidants 9(3):229, 2020). [ABSTRACT FROM AUTHOR]

The North-western Himalayan region requires unique varietal traits for the cultivation and quality of grain produced. Wheat varieties released for this zone in the past remained very popular among the farmers. However, with the passage of time certain traits such as the appearance of pathogenic rust races and grain softness have become threat to the fecundity of these genotypes and needs immediate improvement in this region. Mutation breeding facilitates improving one or two traits of a popular cultivar and to generate variability for most of plant traits upon which selection can be imposed. The purpose of this study is to evaluate the mutagenic sensitivity, effectiveness and efficiency of physical and chemical mutagens in four bread wheat varieties with differential grain texture. Four bread wheat varieties; HS 490, HPW 89, HPW 360 and HPW 251 were irradiated using six doses of gamma rays (γ-rays) ranging from 175 to 300 Gy; Co60 source (BARC, Mumbai, India) and six doses of ethyl methane sulfonate (EMS) ranging from 0.3 to 1.3%; EMS (Sigma-Aldrich, Bangalore, India) to assess their mutation sensitivity, effectiveness, efficiency and spectrum of induced macro-mutations in M1 and M2 generation. Based on mutagen sensitivity tests, both gamma rays and ethyl methane sulfonate had similar effects as the doses/concentrations increased in all four varieties. Ethyl methane sulfonate had a discernible effect on seed germination and growth parameters as compared to gamma irradiated treatments. Pollens viability studies confirmed the differential effects of both mutagens on germination and plant survivability. The LD50 and LC50 values varied between 290–315 Gy for gamma rays and 0.90–1.35% for EMS under controlled laboratory conditions, however, the range substantially differs for gamma rays (240–290 Gy) and for EMS (0.50–1.1%) under field conditions, irrespective of the variety treated. The frequency of chlorophyll mutations was low and showed a linear correlation with the doses/concentrations of the mutagen. A total of 117 putative mutants with desirable agro-morphological characteristics were also isolated. Mutagenic effectiveness and efficiency results showed that gamma irradiation doses of 250–300 Gy and ethyl methane sulfonate of 0.7–1.3% were most potent for an effective mutation breeding programme in wheat crop. It was found that semi-hard textured varieties showed higher sensitivity to chemical mutagens as compared to soft-textured varieties. Gamma irradiation dose of 250–300 Gy and ethyl methane sulfonate concentration of 0.7–1.3% were found to be most effective and efficient across four bread wheat varieties and can be used in large scale mutagenesis programmes. [ABSTRACT FROM AUTHOR]

The incidence of DNA damage from exposure to specific types of metalworking fluids has been reported. In this research, size-selective permissible limits to prevent genotoxic damage in A549 cell lines exposed to two types of mineral oil were estimated for the first time using a benchmark dose approach and extrapolated to workers. The comet assay was performed based on Olive and Banath protocol to determine DNA damage. Then, the Benchmark Dose, the 95% lower bound confidence limit BMD, and the 95% upper-bound confidence limit BMD were determined using continuous response data. Finally, the four Benchmark Dose levels reported in the A549 cell line were extrapolated to the human population in occupational settings in two phases. This study showed when determining the permissible limits, the type used or unused, the type of injury, the organ affected in the body and the size of the particles should also be considered. [ABSTRACT FROM AUTHOR]

Background: As calcium silicate-based cements (CSCs) have found success in various vital pulp therapy applications, several new CSC products have emerged. This study aimed to assess the genotoxicity, cytotoxicity, and bioactivity of four CSCs by comparing the newly introduced materials Bio MTA+ and MTA Cem with previously studied materials, Biodentine and NeoMTA. Methods: Genotoxicity was evaluated using the micronucleus (MN) assay in human peripheral blood lymphocyte cells, measuring MN frequency and nuclear division index (NDI). Cytotoxicity was assessed in human dental pulp stem cells through the Water-Soluble Tetrazolium Salt-1 (WST-1) colorimetric assay. Bioactivity was determined by ELISA, measuring the levels of angiogenic and odontogenic markers (BMP-2, FGF-2, VEGF, and ALP). Statistical analyses included ANOVA, Dunnet and Sidak tests, and Wald chi-square test. (p <.05). Results: The MN frequency in the groups was significantly lower than that in the positive control group (tetraconazole) (p <.05). NDI values decreased with increasing concentration (p <.05). Bio MTA+ and NeoMTA showed decreased cell viability at all concentrations in 7-day cultures (p <.01). All materials increased BMP-2, FGF-2, and VEGF levels, with Biodentine and NeoMTA showing the highest levels of BMP-2 and FGF-2 on day 7. Biodentine displayed the highest VEGF levels on day 7. Biodentine and NeoMTA groups exhibited significantly higher ALP activity than the Bio MTA+ and MTA Cem groups by day 7. Conclusion: Bio MTA+ and MTA Cem demonstrated no genotoxic or cytotoxic effects. Moreover, this study revealed bioactive potentials of Bio MTA+ and MTA Cem by enhancing the expression of angiogenic and osteogenic growth factors. [ABSTRACT FROM AUTHOR]

Context: SARS-CoV-2 virus causes COVID-19 by infecting nasal and oral cavities primarily by attaching its spike proteins to ACE 2 receptors expressed in epithelial cells. Aim: This study was done to evaluate the micronucleated cell count, metanuclear abnormalities, and genotoxic factor in exfoliated buccal mucosal cell among the COVID-19 suspected patients. Settings and Design: This cross-sectional study was conducted at AIIMS, Mangalagiri, between August and October 2022. Methods: One hundred COVID-19 suspected patients were recruited for this study after obtaining informed and written consent; buccal smear was obtained and stained for papanicolaou test (PAP). The PAP-stained slides were analyzed for micronuclei (MN), pyknotic, karyolytic, and karyorrhexic cell count, respectively. Based on their reverse transcription-polymerase chain reaction (RT-PCR) report, the patients were grouped into COVID-19 positive and negative groups. Statistical Analysis: The genotoxicity factor was calculated using the micronucleated cell count from both the groups using mean and standard deviation. Results: The MN, micronucleated cell, pyknotic, karyolitic, and karyorrhexic cell count in COVID-19 positive patients were 24.12, 15.24, 3.08, 2.88 and 4.40, respectively, than COVID-19 negative patients 5.69, 8.17, 1.08, 1.00 and 2.43, respectively. The genotoxicity factor for SARS-CoV-2 was 2.68 which is a positive genotoxic effect on buccal mucosal cells. Conclusion: SARS-CoV-2 increases the expression of micronucleated cells, pyknotic cells, karyolytic cells, and karyorhexic cells and concludes SARS-CoV-2 is having cytogenotoxic effect on the buccal mucosal cells. This can be used as a reliable marker in identifying the early carcinogenic effects of virus causing COVID-19. [ABSTRACT FROM AUTHOR]

BACKGROUND: Chemicals that induce mammary tumors in rodents or activate estrogen or progesterone signaling are likely to increase breast cancer (BC) risk. Identifying chemicals with these activities can prompt steps to protect human health. OBJECTIVES: We compiled data on rodent tumors, endocrine activity, and genotoxicity to assess the key characteristics (KCs) of rodent mammary carcinogens (MCs), and to identify other chemicals that exhibit these effects and may therefore increase BC risk. METHODS: Using authoritative databases, including International Agency for Research on Cancer (IARC) Monographs and the US Environmental Protection’s (EPA) ToxCast, we selected chemicals that induce mammary tumors in rodents, stimulate estradiol or progesterone synthesis, or activate the estrogen receptor (ER) in vitro. We classified these chemicals by their genotoxicity and strength of endocrine activity and calculated the overrepresentation (enrichment) of these KCs among MCs. Finally, we evaluated whether these KCs predict whether a chemical is likely to induce mammary tumors. RESULTS: We identified 279 MCs and an additional 642 chemicals that stimulate estrogen or progesterone signaling. MCs were significantly enriched for steroidogenicity, ER agonism, and genotoxicity, supporting the use of these KCs to predict whether a chemical is likely to induce rodent mammary tumors and, by inference, increase BC risk. More MCs were steroidogens than ER agonists, and many increased both estradiol and progesterone. Enrichment among MCs was greater for strong endocrine activity vs. weak or inactive, with a significant trend. DISCUSSION: We identified hundreds of compounds that have biological activities that could increase BC risk and demonstrated that these activities are enriched among MCs. We argue that many of these should not be considered low hazard without investigating their ability to affect the breast, and chemicals with the strongest evidence can be targeted for exposure reduction. We describe ways to strengthen hazard identification, including improved assessments for mammary effects, developing assays for more KCs, and more comprehensive chemical testing. [ABSTRACT FROM AUTHOR]

Many toxic metals are involved in the initiation and progression of DNA damage that can result in the activation of DNA damage response machinery at double- and single-stranded DNA; this response can result in global and gene-specific DNA alteration. The toxicological profiles from the Agency for Toxic Substances and Disease Registry (ATSDR) and several other studies have demonstrated the influence of metal exposure-induced genotoxic endpoints and epigenetic modifications. Our review systematically summarizes accumulating evidence from ATSDR toxicological profiles and the available literature that demonstrate a possible induction of various genotoxic endpoints and metal exposures. We include in this article studies on chromium, arsenic, nickel, lead, mercury, and zinc. [ABSTRACT FROM AUTHOR]

Humans are constantly exposed to mixtures of different xenobiotics through their diet. One emerging concern is the Alternaria mycotoxin alternariol (AOH), which can occur in foods typically contaminated by the process contaminant acrylamide (AA). AA is a byproduct of the Maillard reaction produced in carbohydrate-rich foods during thermal processing. Given the genotoxic properties of AOH and AA as single compounds, as well as their potential co-occurrence in food, this study aimed to assess the cytotoxic, genotoxic, and mutagenic effects of these compounds in combination. Genotoxicity was assessed in HepG2 cells by quantifying the phosphorylation of the histone γ-H2AX, induced as a response to DNA double-strand breaks (DSBs). Mutagenicity was tested in Salmonella typhimurium strains TA98 and TA100 by applying the Ames microplate format test. Our results showed the ability of AOH and AA to induce DSBs and increase revertant numbers in S. typhimurium TA100, with AOH being more potent than AA. However, no synergistic effects were observed during the combined treatments. Notably, the results of the study suggest that the compounds exert mutagenic effects primarily through base pair substitutions. In summary, the data indicate no immediate cause for concern regarding synergistic health risks associated with the consumption of foods co-contaminated with AOH and AA. [ABSTRACT FROM AUTHOR]

Cancer is a genetic disease requiring multiple mutations for its development. However, many carcinogens are DNAunreactive and nonmutagenic and consequently described as nongenotoxic. One of such carcinogens is nickel, a global environmental pollutant abundantly emitted by burning of coal. We investigated activation of DNA damage responses by Ni and identified this metal as a replication stressor. Genotoxic stress markers indicated the accumulation of ssDNA and stalled replication forks, and Ni-treated cells were dependent on ATR for suppression of DNA damage and long-term survival. Replication stress by Ni resulted from destabilization of RRM1 and RRM2 subunits of ribonucleotide reductase and the resulting deficiency in dNTPs. Ni also increased DNA incorporation of rNMPs (detected by a specific fluorescent assay) and strongly enhanced their genotoxicity as a result of repressed repair of TOP1-DNA protein crosslinks (TOP1-DPC). The DPC-trap assay found severely impaired SUMOylation and K48-polyubiquitination of DNA-crosslinked TOP1 due to downregulation of specific enzymes. Our findings identified Ni as the human carcinogen inducing genome instability via DNA-embedded ribonucleotides and accumulation of TOP1-DPC which are carcinogenic abnormalities with poor detectability by the standard mutagenicity tests. The discovered mechanisms for Ni could also play a role in genotoxicity of other protein-reactive carcinogens. [ABSTRACT FROM AUTHOR]

Background/aim: Hearing loss caused by exposure to noise is still among the most prevalent health risks for industrial workers. This study aims to evaluate the relationship between Shebien El-kom textile factory workers' occupational noise exposure, genotoxicity, and noise-induced hearing loss. Methods: This cross-sectional case–control study was performed in a textile industry in Shebin Elkom, Egypt. The participants of this work were 36 exposed male workers from the spinning section of the textile factory and 36 subjects as the control male group from administrative staff in the same factory, in the age range of 25–45 years. A pure-tone audiometer and portable sound level meter were utilized for the measurement of hearing threshold and noise level, respectively. Genotoxicity was assessed using the Comet assay technique. Results: There was no significant difference between both groups regarding age and the mean duration of work was 18.94 ± 4.88 for exposed workers. The average level of noise was 95–105 dB (A). The exposed workers' mean hearing thresholds for the left and right ears at frequencies between 2000 and 8000 Hz were substantially greater than those of the control group (P < 0.05). In the exposed workers, there was not a marked variation between the hearing thresholds of the left and right ears (p > 0.05). The exposed workers' percentage of DNA damage was substantially greater than that of the control group (p < 0.001). Among exposed workers, a positive correlation between DNA damage, the degree of hearing loss, and the duration of time exposed to noise was demonstrated. Conclusion: The majority of exposed workers suffered from occupational noise-induced hearing loss. A positive correlation was found between the percentage of DNA damage, duration of exposure to noise, and hearing threshold in exposed workers. [ABSTRACT FROM AUTHOR]

Background: Cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) are frequently used in dental and maxillofacial problems. This study aimed to assess the genotoxicity and cytotoxicity effects of CBCT and MDCT radiographies on exfoliated buccal epithelial cells during dental examinations. Methods: This prospective experimental study was conducted at Babol University of Medical Sciences (Babol, Iran) from March 2021 to April 2021. Buccal mucosa smears were collected bilaterally pre-exposure and 12 days after CBCT or MDCT examinations. To compare the frequency of micronuclei and other cytotoxic cellular changes such as pyknosis, karyolysis, and karyorrhexis, the paired sample t test and Wilcoxon test were used. In addition, independent sample t test, Mann-Whitney, and Chi square tests were used to investigate the differences between the imaging methods and between men and women. All statistical analyses were performed using the SPSS software, and P≤0.05 was considered statistically significant. Results: The current study included 60 adult patients (30 patients in each group), ranging in age from 21 to 50 years. The micronuclei and the other cytotoxic cellular changes increased significantly after CBCT and MDCT radiographic examinations on the 12th day compared to the pre-exposure results (P<0.001). MDCT had statistically higher cytotoxic and genotoxic effects than CBCT (9.4%, 23.1%, and 40% higher values in micronucleus frequency, the mean frequency of micronuclei, and other cytotoxic changes, respectively). There were no significant differences between men and women in the two examination methods (P=0.46 and P=0.49, respectively). Conclusion: Dental examinations with CBCT and MDCT can increase cytotoxicity and chromosomal damage in both men and women. Due to its lower radiation toxicities, CBCT can be recommended as an alternative to MDCT for dental examinations. [ABSTRACT FROM AUTHOR]

Background: Although chlorpyrifos (CPS) has been banned in many developed countries, it still remains one of the best-selling pesticides in the world. Widespread environmental and occupational exposure to CPS pose a serious risk to human health. Another environmental factor that can adversely affect human health is ultraviolet radiation B (UVB, 280–315 nm wave length). Here we attempt determine if exposure to CPS can modify toxic effects of UVB. Such situation might be a common phenomenon in agriculture workers, where exposure to both factors takes place. Methods: Two skin cell lines; namely human immortalized keratinocytes HaCaT and BJ human fibroblasts were used in this study. Cytotoxicity was investigated using a cell membrane damage detection assay (LDH Cytotoxicity Assay), a DNA damage detection assay (Comet Assay), an apoptosis induction detection assay (Apo-ONE Homogeneous Caspase-3/7 Assay) and a cell reactive oxygen species detection assay (ROS-Glo H2O2 assay). Cytokine IL-6 production was also measured in cells using an ELISA IL-6 Assay. Results: Pre-incubation of skin cells with CPS significantly increased UVB-induced toxicity at the highest UVB doses (15 and 20 mJ/cm2). Also pre-exposure of BJ cells to CPS significantly increased the level of DNA damage, except for 20 mJ/cm2 UVB. In contrast, pre-exposure of HaCaT cells, to CPS prior to UVB radiation did not cause any significant changes. A decrease in caspase 3/7 activity was observed in HaCaT cells pre-exposed to 250 µM CPS and 5 mJ/cm2 UVB. Meanwhile, no statistically significant changes were observed in fibroblasts. In HaCaT cells, pre-exposure to CPS resulted in a statistically significant increase in ROS production. Also, in BJ cells, similar results were obtained except for 20 mJ/cm2. Interestingly, CPS seems to inhibited IL-6 production in HaCaT and BJ cells exposed to UVB (in the case of HaCaT cells for all UVB doses, while for BJ cells only at 15 and 20 mJ/cm2). Conclusions: In conclusion, the present study indicates that CPS may contribute to the increased UVB-induced toxicity in skin cells, which was likely due to the induction of ROS formation along with the generation of DNA damage. However, further studies are required to gain better understanding of the mechanisms involved. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the cytotoxic, genotoxic and mutagenic properties of two experimental medication in Endodontics. For cytotoxic evaluation, fibroblast and osteoblast cells (1x104 cells/well) were plated and divided into groups conforming to the product added in culture medium: EM1 - 20 µL of experimental medication 1 (EM1); EM2 - 20 µL of experimental medication 2 (EM2); VE - 20 µL of vehicle used in medications; C - without product. The MTT assay was performed at 24, 48 e 72 hours for cytotoxic analysis. For genotoxic and mutagenic evaluation, 42 male rats were used. After 1 and 7 days of tubes containing EM1 or EM2, or empty (NC) were subcutaneously implanted, and after 1 day, a single dose of cyclophosphamide (CY) to be applied, the bone marrow was collected and submitted to comet and micronuclei assay. The significance level of 5% was considered for all statistical analysis. The viability of fibroblasts was <70% to both medications at 24h, and EM1 at 72h; at 72h, the proliferation cells was observed in EM2 (>100%). Both medications were non-cytotoxic to osteoblasts, and the EM2 stimulate the cell proliferation at 72h. The damage frequency of CY was statistically similar to EM1 and different to EM2 (p<0.05). The number of micronuclei was insignificant to EM1 and EM2 and no difference to group NC (p>0.05). Despite the absence of mutagenesis and non-cytotoxicity to osteoblasts, the EM1 was cytotoxic and genotoxic to fibroblasts. The EM2 was non-genotoxic, non-cytotoxic and nonmutagenic. [ABSTRACT FROM AUTHOR]

The blood cell phosphatidylinositol glycan class A (PIG‐A) gene mutation assay has been extensively researched in rodents for in vivo mutagenicity testing and is now being investigated in humans. The PIG‐A gene is involved in glycosyl phosphatidylinositol (GPI)‐anchor biosynthesis. A single mutation in this X‐linked gene can lead to loss of membrane‐bound GPI anchors, which can be enumerated via corresponding GPI‐anchored proteins (e.g., CD55) using flow cytometry. The studies published to date by different research groups demonstrate a remarkable consistency in PIG‐A mutant frequencies. Moreover, with the low background level of mutant erythrocytes in healthy subjects (2.9–5.56 × 10−6 mutants), induction of mutation post genotoxic exposure can be detected. Cigarette smoking, radiotherapy, and occupational exposures, including lead, have been shown to increase mutant levels. Future applications of this test include identifying new harmful agents and establishing new exposure limits. This mutational monitoring approach may also identify individuals at higher risk of cancer development. In addition, identifying protective agents that could mitigate these effects may reduce baseline somatic mutation levels and such behaviors can be encouraged. Further technological progress is required including establishing underlying mechanisms of GPI anchor loss, protocol standardization, and the development of cryopreservation methods to improve GPI‐anchor stability over time. If successful, this assay has the potential be widely employed, for example, in rural and low‐income countries. Here, we review the current literature on PIG‐A mutation in humans and discuss the potential role of this assay in human biomonitoring and disease detection. [ABSTRACT FROM AUTHOR]

The article discusses the Court of Justice has ruled that in vitro random mutagenesis should not be treated similarly to conventional mutagenesis methods under Directive 2001/18, as it can lead to genetic modifications with different nature or rate. It reports that vitro applications with a long safety record may still qualify for exemption.

The non-structural protein (NSs) and nucleoprotein (NP) of the severe fever with thrombocytopenia syndrome virus (SFTSV) encoded by the S segment are crucial for viral pathogenesis. They reside in viroplasm-like structures (VLS), but their interaction and their significance in viral propagation remain unclear. Here, we investigated the significance of the association between NSs and NP during viral infection through in-silico and in-vitro analyses. Through in-silico analysis, three possible binding sites were predicted, at positions C6S (Cystein at 6th position to Serine), W61Y (Tryptophan 61st to Tyrosine), and S207T (Serine 207th to Threonine), three mutants of NSs were developed by site-directed mutagenesis and tested for NP interaction by co-immunoprecipitation. NSsW61Y failed to interact with the nucleoprotein, which was substantiated by the conformational changes observed in the structural analyses. Additionally, molecular docking analysis corroborated that the NSW61Y mutant protein does not interact well compared to wild-type NSs. Over-expression of wild-type NSs in HeLa cells increased the SFTSV replication by five folds, but NSsW61Y exhibited 1.9-folds less viral replication than wild-type. We demonstrated that the W61Y alteration was implicated in the reduction of NSs-NP interaction and viral replication. Thus, the present study identified a critical NSs site, which could be targeted for development of therapeutic regimens against SFTSV. [ABSTRACT FROM AUTHOR]

Calcium carbide (CaC2) and ethylene glycol (EG) are the two commonly used fruit ripening agents. The toxic effects of these chemicals on internal organs were reported in experimental animals. Even though the adverse effects of these compounds have been investigated for many years, there are no sufficient data available with regard to genotoxic effects. The present study evaluates the genotoxic effect of chronic exposures of CaC2 and EG in Wistar albino rats. CaC2 and EG were administered to the rats orally for 180 days. Chromosomal aberrations and micronuclei formation were analysed in bone marrow and peripheral blood cells. Comet assay was performed to analyse the DNA strand break. The toxic effects of the chemicals were analysed by MTT assay with normal human intestinal epithelial (IEC-6) cells. Upon chronic exposure, CaC2 and EG caused chromosomal aberrations, micronuclei formation and DNA strand breaks extensively in bone marrow and peripheral blood cells. In MTT assay, the chemicals were found to be toxic to IEC-6 cells with IC50 values at 160 and 200 μg/mL for CaC2 and EG, respectively. The results show that these chemicals have a potential to cause genomic level of toxicity which may lead to carcinogenic event at a chronic level exposure. The study warns to reinforce the administrative measures against the use of CaC2 and EG for fruit ripening process. – Industrial grade CaC2 and EG show genotoxicity at the chronic exposure in animals at lower doses. – In vitro cytotoxicity by CaC2 and EG towards IEC-6 cell line exhibited dose dependent decrease of cell proliferation. – Chromosomal aberrations, micronuclei formation, DNA breakage (comet assay) suggest potentially pre-mutagenic lesions by the toxicity. – These chemicals have the potential for genotoxic and carcinogenic effect. – The study warns the health risks of consumption of fruits ripened with calcium carbide and ethylene glycol. [ABSTRACT FROM AUTHOR]

The article aimed to assess the Vicia faba plant's suitability in the micronucleus test for determining toxicity of wastewater containing diclofenac and sulfamethoxazole. Additionally, the study evaluated the activity of the antioxidant enzymes catalase and superoxide dismutase in plant leaves. The assessment of wastewater was performed on laboratory-constructed wetland models. Both influent and effluent samples were tested, and the study examined two methods of plant root exposure: hydroponic culture and soil culture. The analysis showed a decrease in the mitotic index (57% inhibition on average in hydroponic and 42% in soil culture for influent and 39% and 19%, respectively, for treated wastewater), indicating the toxicity of the wastewater. The inhibition of the cell division frequency was lower in soil culture, and the frequency of aberrations of chromosomes was also lower. However, there was no increase in micronuclei frequency. An upsurge in catalase activity was observed upon analyzing the wastewater, with a 67% increase in the influent and a 20% increase in the treated wastewater. Additionally, there was a notable boost in superoxide dismutase activity, primarily in hydroponic culture with raw wastewater, averaging 186%. The results showed genotoxic and cytotoxic effects, but there were no mutagenic effects. The Vicia faba assay is advantageous for its simplicity and rapid results; it offers representative assessment of genotoxicity through its broad range of detected effects. [ABSTRACT FROM AUTHOR]

Mutagenicity testing is an essential component of health safety assessment. Duplex Sequencing (DS), an emerging high-accuracy DNA sequencing technology, may provide substantial advantages over conventional mutagenicity assays. DS could be used to eliminate reliance on standalone reporter assays and provide mechanistic information alongside mutation frequency (MF) data. However, the performance of DS must be thoroughly assessed before it can be routinely implemented for standard testing. We used DS to study spontaneous and procarbazine (PRC)-induced mutations in the bone marrow (BM) of MutaMouse males across a panel of 20 diverse genomic targets. Mice were exposed to 0, 6.25, 12.5, or 25 mg/kg-bw/day for 28 days by oral gavage and BM sampled 42 days post-exposure. Results were compared with those obtained using the conventional lacZ viral plaque assay on the same samples. DS detected significant increases in mutation frequencies and changes to mutation spectra at all PRC doses. Low intra-group variability within DS samples allowed for detection of increases at lower doses than the lacZ assay. While the lacZ assay initially yielded a higher fold-change in mutant frequency than DS, inclusion of clonal mutations in DS mutation frequencies reduced this discrepancy. Power analyses suggested that three animals per dose group and 500 million duplex base pairs per sample is sufficient to detect a 1.5-fold increase in mutations with > 80% power. Overall, we demonstrate several advantages of DS over classical mutagenicity assays and provide data to support efforts to identify optimal study designs for the application of DS as a regulatory test. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) light primarily causes C > T substitutions in lesion-forming dipyrimidine sequences. However, many of the key driver mutations in melanoma do not fit this canonical UV signature, but are instead caused by T > A, T > C, or C > A substitutions. To what extent exposure to the UVB or UVA spectrum of sunlight can induce these noncanonical mutation classes, and the molecular mechanism involved is unclear. Here, we repeatedly exposed wild-type or repair-deficient yeast (Saccharomyces cerevisiae) to UVB or UVA light and characterized the resulting mutations by whole genome sequencing. Our data indicate that UVB induces C > T and T > C substitutions in dipyrimidines, and T > A substitutions that are often associated with thymine–adenine (TA) sequences. All of these mutation classes are induced in nucleotide excision repair–deficient cells and show transcriptional strand asymmetry, suggesting they are caused by helix-distorting UV photoproducts. In contrast, UVA exposure induces orders of magnitude fewer mutations with a distinct mutation spectrum. UVA-induced mutations are elevated in Ogg1-deficient cells, and the resulting spectrum consists almost entirely of C > A/G > T mutations, indicating they are likely derived from oxidative guanine lesions. These mutations show replication asymmetry, with elevated G > T mutations on the leading strand, suggesting there is a strand bias in the removal or bypass of guanine lesions during replication. Finally, we develop a mutation reporter to show that UVA induces a G > T reversion mutation in yeast that mimics the oncogenic NRAS Q61K mutation in melanoma. Taken together, these findings indicate that UVA and UVB exposure can induce many of the noncanonical mutation classes that cause driver mutations in melanoma. [ABSTRACT FROM AUTHOR]

The regioselective synthesis of a new series of pyrazolo[5,1‐b]quinazolines was carried out using a three‐component protocol. The protocol involved the reaction of the appropriate benzaldehydes, dimedone, and 1H‐pyrazole‐ 3,5‐diamine in DMF at 150 °C. Using a similar protocol, three additional series of bis(pyrazolo[5,1‐b]quinazolines), linked to different spacers, were prepared utilizing the respective bis(aldehydes). The new products showed a wide spectrum of antibacterial activity against six different the American Type Culture Collection (ATCC) bacterial strains. In general, p‐xylene‐linked bis(pyrazolo[5,1‐b]quinazolines) had good antibacterial activity with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values up to 8.3 and 16.6 μM, respectively. Additionally, (4‐nitrophenyl)‐linked pyrazolo[5,1‐b]quinazoline had the best antibacterial activity with MIC/MBC values up to 2.1/4.3 μM. The Salmonella typhimurium reverse mutation assay (Ames mutagenicity test) was used to conclude that the (4‐nitrophenyl)‐linked product was not mutagenic to the Salmonella strains. Both the drug‐likeness model score and the SwissADME predict the (4‐nitrophenyl)‐linked product's good physicochemical properties, and drug likeness. [ABSTRACT FROM AUTHOR]

The goal of this paper is to assess the mutagenic and genotoxic potentials of avocado oil made from the fruit pulp of Persea Americana, a member of the Lauraceae family. Michigan Cancer Foundation-7 (MCF-7) cells are used in the 3-4,5 dimethylthiazol-2yl-2,5-diphenyl tetrazolium bromide (MTT) test to examine the possible antiproliferative and cytostatic qualities of different doses of avocado oil, and MCF-7 cells are used in the comet assay to examine the potential cytostatic effects of avocado oil extracted from the avocado fruit. DNA in human breast cancer cells is partially damaged by avocado oil. However, DNA damage at low, medium, and high levels was discovered in the positive control. Without positive control, the DNA damage level falls in the low, middle, and high ranges. The MTT assay shows that avocado oil exerts a dose-dependent cytostatic impact on human breast cancer MCF-7 cells with an IC50 value of 379.2 µg/mL, which is the IC50 value that causes genotoxicity in the comet assay. [ABSTRACT FROM AUTHOR]

Arrestin-1, or visual arrestin, exhibits an exquisite selectivity for light-activated phosphorylated rhodopsin (P-Rh*) over its other functional forms. That selectivity is believed to be mediated by two well-established structural elements in the arrestin-1 molecule, the activation sensor detecting the active conformation of rhodopsin and the phosphorylation sensor responsive to the rhodopsin phosphorylation, which only active phosphorylated rhodopsin can engage simultaneously. However, in the crystal structure of the arrestin-1–rhodopsin complex there are arrestin-1 residues located close to rhodopsin, which do not belong to either sensor. Here we tested by site-directed mutagenesis the functional role of these residues in wild type arrestin-1 using a direct binding assay to P-Rh* and light-activated unphosphorylated rhodopsin (Rh*). We found that many mutations either enhanced the binding only to Rh* or increased the binding to Rh* much more than to P-Rh*. The data suggest that the native residues in these positions act as binding suppressors, specifically inhibiting the arrestin-1 binding to Rh* and thereby increasing arrestin-1 selectivity for P-Rh*. This calls for the modification of a widely accepted model of the arrestin–receptor interactions. [ABSTRACT FROM AUTHOR]

The TCR integrates forces in its triggering process upon interaction with pMHC. Force elicits TCR catch-slip bonds with strong pMHCs but slip-only bonds with weak pMHCs. We develop two models and apply them to analyze 55 datasets, demonstrating the models' ability to quantitatively integrate and classify a broad range of bond behaviors and biological activities. Comparing to a generic two-state model, our models can distinguish class I from class II MHCs and correlate their structural parameters with the TCR/pMHC's potency to trigger T cell activation. The models are tested by mutagenesis using an MHC and a TCR mutated to alter conformation changes. The extensive comparisons between theory and experiment provide model validation and testable hypothesis regarding specific conformational changes that control bond profiles, thereby suggesting structural mechanisms for the inner workings of the TCR mechanosensing machinery and plausible explanations of why and how force may amplify TCR signaling and antigen discrimination. Catch bonds where lifetime increases with force applied can form when T cell receptors (TCR) interact with agonist peptide-MHC (pMHC) complexes. Here the authors use a modelling and experimental approach to analyse 55 TCR–pMHC bond lifetime curves measured under force to further characterise the structural bases and functional relevance of catch bonds. [ABSTRACT FROM AUTHOR]

Objective: To determine whether budesonide (Bud) and triamcinolone acetate (TA) cause DNA fractures in the nasal mucosa and septal cartilage cells through examinations using the comet assay technique. Study design: Prospective, controlled experimental study. Setting: University hospital. Methods: Septal mucosal epithelial and cartilage tissue samples were taken from 9 patients. Cell cultures were prepared from these samples. Then, budesonide and triamcinolone acetate active ingredients at 2 different doses of 0.2 and 10 µM were separately applied to the cell cultures formed from both tissues of each patient, except the control cell culture, for 7 days in one group and 14 days in one group. After the applications, genotoxic damage was scored with the comet assay technique and the groups were compared. Results: In both the budesonide and triamcinolone acetate groups, the comet scores at low and high doses, on the 7th and 14th days were found to be significantly higher in both cartilage and epithelial tissue than in the control group. Conclusion: The study results showed that budesonide and triamcinolone acetate lead to a significantly high rate of genotoxic damage in both epithelial tissue and cartilage tissue. [ABSTRACT FROM AUTHOR]