Biomonitoring of metals in the blood and urine of waste recyclers from exposure to airborne fine particulate matter (PM2.5)

This is the first systematic investigation of occupational exposure to toxic metals among waste recyclers in municipal waste recycling facilities. Concentrations of heavy metals (HMs) in the blood and urine of exposed recyclers in different jobs were compared to control groups (administrative department), identifying possible work-related and socio-demographic exposure factors. The potential relationship between HMs levels in PM2.5 and HM concentrations in the blood and urine of recyclers was studied for ten elements. Mean concentrations of HMs of recyclers were significantly higher than for the control group. Over 50% of the waste recyclers had HM levels higher than the recommended limits. The study revealed that most of the waste recyclers engaged in a minimum of three tasks, posing a challenge in establishing a correlation between specific tasks and the levels of elements monitored through biomonitoring. Co levels in blood and Fe levels in the urine of waste recyclers have a significant relationship with the increase in daily working hours. Among the variables related to the participant's demographic information, the level of education and monthly income were significantly different compared to the control group. Also, a significant correlation was found between HM levels in PM2.5 personal exposure and recyclers' urine and blood. Management controls include workflow or, in other words, alternate relocation of workers exposed to severe risks. Engineering controls such as ventilation systems, applying appropriate personal protective equipment (PPE), and risk management methods are the implementation cases to reduce exposure.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40201-024-00924-y.

The cGAS-STING-mediated ROS and ferroptosis are involved in manganese neurotoxicity

Manganese (Mn) has been characterized as an environmental pollutant. Excessive releases of Mn due to human activities have increased Mn levels in the environment over the years, posing a threat to human health and the environment. Long-term exposure to high concentrations of Mn can induce neurotoxicity. Therefore, toxicological studies on Mn are of paramount importance. Mn induces oxidative stress through affecting the level of reactive oxygen species (ROS), and the overabundance of ROS further triggers ferroptosis. Additionally, Mn2+ was found to be a novel activator of the cyclic guanosine-adenosine synthase (cGAS)-stimulator of interferon genes (STING) pathway in the innate immune system. Thus, we speculate that Mn exposure may promote ROS production by activating the cGAS-STING pathway, which further induces oxidative stress and ferroptosis, and ultimately triggers Mn neurotoxicity. This review discusses the mechanism between Mn-induced oxidative stress and ferroptosis via activation of the cGAS-STING pathway, which may offer a prospective direction for future in-depth studies on the mechanism of Mn neurotoxicity.

Biogenic emission as a potential source of atmospheric aromatic hydrocarbons: Insights from a cyanobacterial bloom-occurring eutrophic lake

As important precursors of ozone (O3) and secondary organic aerosol (SOA), reactive aromatic hydrocarbons (AHs) have typically been classified as anthropogenic air pollutants. However, biogenic emission can also be a potential source of atmospheric AHs. Herein, field observations in a eutrophic lake were combined with laboratory incubation experiments to investigate the biogenic AH emission. Field work showed that the water-air fluxes of AHs measured at sites with high cyanobacteria abundance could reach an order of magnitude greater than those at sites with low cyanobacteria abundance, suggesting that cyanobacteria could be the important contributor to measured AHs. Laboratory incubation experiments further confirmed the AH emission of cyanobacteria and revealed that the emission could change significantly over the lifespan of cyanobacteria and varied to their growing conditions. By combining field observations and laboratory incubation experiments, it has been suggested that the emission of different AH species from cyanobacteria could be modulated by variable biogeochemical mechanisms and that the biochemical process of toluene could be different from that of other AHs. This study investigates AH emissions from inland aquatic ecosystem and suggests that biogenic emission could be a potential source of atmospheric AHs.

Identification of Beauvericin metabolites using rat and human liver microsomes and in vivo urinary excretion study in rats for biomonitoring application

Beauvericin (BEA), an emerging mycotoxin, belongs to a class characterized by a cyclic depsipeptide ring structure, commonly produced by fungal species like Fusarium sp. and Beauveria bassiana. BEA is known for contaminating cereals and grains (wheat, maize). Humans might be exposed to BEA through contaminated food. Biomonitoring is a valuable method for assessing environmental and occupational exposure to specific chemicals. These studies measure chemical biomarkers to quantify exposure for public health risk assessment. However, identifying specific and sensitive chemical biomarkers for BEA exposure remains challenging. In the present study, metabolites of BEA were identified through in vitro metabolism studies conducted in the rat (RLM) and human liver microsomes (HLM) using the liquid chromatography-high resolution mass spectrometry (LC-HRMS) technique. Seventeen metabolites were characterized, showcasing products of oxidation, reduction, and deamination reactions. Predominantly, oxidative metabolites resulting from mono‑oxygenation, di‑oxygenation, and tri‑oxygenation were observed. The metabolites in RLM primarily consisted of mono and di‑oxygenated forms, while in HLM, tri‑oxygenated and demethylated products were also found. Furthermore, in vivo excretion study in rat urine samples confirmed the presence of oxygenated metabolites detected in the in vitro samples. Consequently, the study suggests that oxygenated metabolites of BEA could serve as useful biomarkers for conducting future biomonitoring studies.

Effects of environmentally relevant concentrations of glyphosate and aminomethylphosphonic acid on biotransformation and stress response proteins in the liver of zebrafish (Danio rerio)

Herbicides pose a threat to various non-target organisms, including fish. A widely used herbicide, glyphosate, and its main breakdown product, aminomethylphosphonic acid (AMPA), are quite ubiquitous in freshwater systems. The aim of this work was to analyze changes in the relative abundance of hepatic proteins participating in the biotransformation and response to chemical stress in adult zebrafish Danio rerio exposed to environmentally relevant concentrations of glyphosate (100 μg/L), AMPA (100 μg/L), and their mixture (50 μg/L + 50 μg/L) for two weeks. Proteomic analysis showed that the tested concentrations caused dysregulation of various biotransformation proteins, the most upregulated of which in all treatment groups was the Phase I enzyme cyp27a7. While glyphosate had a more pronounced impact on the biotransformation pathways, AMPA showed stronger interference with redox homeostasis. When acting together, the parent compound and its metabolite were more potent to disturb fish metabolic processes, including nucleotide metabolism and proteasome pathway, and to downregulate proteins known for their roles in protection from oxidative modifications of cellular constituents and disruption of redox signaling.

Development of a high-performance optical sensor for sensitive detection of cobalt ions in pharmaceutical, food, biological, and environmental samples

A re-generable optical chemical sensing film was created using a modified chitosan film that incorporates immobilized 4-(thiazol-2-yldiazenyl) benzene-1,3-diol (TDBD) for the detection of Co2+ in acidic aqueous solutions. Upon exposure to Co2+, the film's color shifted from yellowish green to red by forming a complex between Co2+ and TDBD. The sensor's complex was measured at 574 nm, a wavelength where the sensing membrane exhibited minimal background interference. The film exhibited its highest responsiveness to cobalt ions at pH 5.0. Two sample volumes were analysed: 2.5 mL with a Co2+ concentration range of 8.0-140 ng/mL, and 250 mL with a concentration range of 2.4-15.2 ng/mL. Both sample sizes produced linear calibration curves, with detection limits of 2.5 and 0.7 ng/mL, respectively. The relative standard deviation was 1.35 % for six separate films in a 100 ng/mL Co2+ solution, and 0.87 % for six individual films in a 10 ng/mL solution using 2.5 and 250 ng/mL, respectively. The sensing films demonstrated good stability over 30 days and were successfully used to determine Co2+ in pharmaceutical, food, environmental, and biological samples, yielding satisfactory results compared to the ICP-AES method.

Hydrazide chemosensor detects fluoride ions cooperatively for binding fluoride and potassium ions

Chemosensors to detect ions have been increasingly studied to distinguish hazardous and economic species, and detecting and recuperating ions is crucial. Searching for a low-cost technique and better chemosensors, our group presents exciting results, using the UV-Vis technique to evidence the effective interaction between the ligand (1) and the anions F-, Ac-, and CrO42-, as well as the NMR titration. Low LOD for these ions (3.0 × 10-7-6.3 × 10-8 moldm-3) showed a high affinity for all the anions. A curious cooperative binding of fluoride and potassium to the ligand was observed for the first time, giving a high sensibility for ligand 1. Due to the high affinity of the ligand for these anionic species, binding strength, and low interference, the excellent applicability of the sensor's potential for environmental problems becomes evident.

Neuroprotection by 4R-cembranoid against Gulf War Illness-related Chemicals is mediated by ERK, PI3K, and CaMKII pathways

Gulf War Illness (GWI) has been consistently linked to exposure to pyridostigmine (PB), N,N-Diethyl-meta-toluamide (DEET), permethrin (PER), and traces of sarin. In this study, diisopropylfluorophosphate (DFP, sarin surrogate) and the GWI-related chemicals were found to reduce the number of functionally active neurons in rat hippocampal slices. These findings confirm a link between GWI neurotoxicants and N-Methyl-D-Aspartate (NMDA)-mediated excitotoxicity, which was successfully reversed by Edelfosine (a phospholipase Cβ (PLCβ3) inhibitor) and Flupirtine (a Kv7 channel agonist). To test whether 4R-cembranoid (4R), a nicotinic α7 acetylcholinesterase receptor (α7AChR) modulator known for its neuroprotective properties, can restore hippocampal neurons from glutamate-induced neurotoxicity, we exposed rat hippocampal slices with DFP for 10 min followed by 60 min treatment with 4R. We investigated the 4R mechanisms of neuroprotection after preincubation with LY294002, PD98059, and KN-62. The inhibition of the phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinase (MEK1/2), and calcium/calmodulin-dependent protein kinase (CaMKII) abrogated the protective effect of 4R against DFP-induced neurotoxicity. In separate experiments, after incubation with DFP, followed by 4R for 1 h, cellular extracts were prepared for Western blotting of phospho-Akt, phospho-GSK3β, phosphorylated extracellular signal-regulated kinase (ERK)1/2, CaMKII and cAMP response element-binding protein (CREB). Our results show that DFP induces neuronal dysfunction by dephosphorylation, while 4R restores the phosphorylation of Akt, GSK3, ERK1/2, CREB, and CaMKII. Moreover, our proteomics analysis supported the notion that 4R activates additional signaling pathways related to enhancing neuronal signaling, synaptic plasticity, and apoptotic inhibition to promote cell survival against DFP, offering biomarkers for developing treatment against GWI.

The molecular mechanisms of TRβ receptor interaction with polychlorinated biphenyls: A multispectral and computational exploration

The thyroid hormone (TH) system is susceptible to the toxic effects of polychlorinated biphenyls (PCBs). Pollutants may disrupt the TH system by binding to serum TH transport proteins or interacting with thyroid hormone receptors (TRs) in target cells. However, the molecular mechanism of interaction with the Thyroid Hormone Receptor Beta (TRβ) is not fully understood. This study employed fluorescence, UV-visible absorption, three-dimensional fluorescence, and Fourier-transform infrared spectroscopy, along with molecular docking and molecular dynamics simulations, to investigate the interaction between TRβ and PCBs. Moreover, molecular docking and fluorescence resonance energy transfer (FRET) findings suggest that TRβ and PCBs underwent resonance energy transfer consistent with Förster's theory. The root mean square deviation (RMSD) and docking outcomes indicate that the TRβ-PCB29 complex exhibited optimal structural stability. Thus, the study concludes that integrating spectroscopic data with molecular docking is essential for a comprehensive analysis. Further analysis of intermolecular interactions using quantum chemistry and reduced density gradient analysis (RDG) analysis revealed that van der Waals forces are the primary drivers of PCBs to TRβ.

A New approach for simultaneous detection and photocatalytic degradation of imidacloprid and dinotefuran in water using terbium-based fluorometry and mixed-phase TiO2

This study explores a novel method for detecting neonicotinoid insecticides, imidacloprid (IMD) and dinotefuran (DNT), in water using terbium (Tb3+) ions photo probe. The optimal excitation and emission wavelengths for Tb3+ luminescence were identified at 310 nm and 545 nm, respectively. The influence of pH and solvent on Tb-complex fluorescence was investigated. Results indicate a significant enhancement of luminescence intensity at pH 6 for IMD in DMF and pH 7.0 for DNT in DMSO. The fluorescence intensity exhibited a linear relationship with IMD and DNT concentrations ranging from 0.1 to 20 µg/mL (R2 > 0.99). Limits of quantitation (LOQ) were determined as 0.1 µg/mL for IMD and 0.05 µg/mL for DNT. This newly developed photo probe demonstrates the potential for monitoring photolysis and photocatalytic degradation of these neonicotinoids using TiO2 as a catalyst under controlled photoreactor conditions. The method offers a promising alternative for rapidly and sensitively detecting these prevalent insecticides in water samples.

DEHP impairs the oxidative stress response and disrupts trace element and mineral metabolism within the mitochondria of detoxification organs

Di(2-ethylhexyl) phthalate (DEHP), a widely utilized plasticizer in various consumer products, is classified as an endocrine disruptor and has been implicated in numerous adverse health effects, including oxidative stress, inflammation, and metabolic disturbances. Despite the growing body of literature addressing the systemic effects of DEHP, the specific influence of DEHP-induced oxidative stress on mitochondrial function within detoxification organs, particularly the liver and kidneys, remains largely unexplored. This study evaluated the effects of DEHP exposure (0, 100, 200, and 400 mg/kg/day) on mitochondrial oxidative stress, trace elements, and mineral metabolism associated with signaling pathways in the liver and kidneys of rats. Altered mitochondrial oxidative stress status was indicated by impaired glucose 6-phosphate dehydrogenase (G6PD), 6-phosphoglucerate dehydrogenase (6-PGD), glutathione reductase (GR), glutathione s-transferase (GST), and glutathione peroxidase (GPx) activities, along with significant disruptions in essential minerals and trace elements, including Na, Mg, Cu, Zn, and Fe. Key oxidative stress signaling pathways, such as NF-κB, Akt, STAT3, and CREB, glucose, and tissue homeostasis, displayed dose-dependent responses to DEHP, indicating complex regulatory mechanisms. This study represents the first comprehensive investigation into DEHP-induced mitochondrial dysfunction, highlighting its effects on oxidative stress metabolism, trace element homeostasis, and cellular signaling pathways in detoxification organs. These findings provide novel insights into the mitochondrial mechanisms underlying DEHP toxicity and underscores the need for further research into the implications of plasticizer exposure on human health.

Specific and potent inhibition of steroid hormone pre-receptor regulator AKR1C2 by perfluorooctanoic acid: Implications for androgen metabolism

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental pollutants that are highly stable synthetic organofluorine compounds. One congener perfluorooctanoic acid (PFOA) can be detected in nearly all humans and is recognized as an endocrine disrupting chemical (EDC). EDCs disrupt hormone synthesis and metabolism and receptor function. One mechanism of steroid hormone action is the pre-receptor regulation of ligand access to steroid hormone receptors by aldo-keto reductases. Here we report PFOA inhibition of AKR family 1 member C2 (AKR1C2), leading to dysregulation of androgen action. Spectrofluorimetric inhibitor screens identified PFOA as a competitive and tight binding inhibitor of AKR1C2, whose role is to inactivate 5α-dihydrotestosterone (5α-DHT). Further site directed mutagenesis studies along with molecular docking simulations revealed the importance of residue Valine 54 in mediating AKR1C2 inhibitor specificity. Binding site restrictions were explored by testing inhibition of other related PFAS chemicals, confirming that steric hinderance is a key factor. Furthermore, radiochromatography using HPLC and in line radiometric detection confirmed the accumulation of 5α-DHT as a result of PFOA inhibition of AKR1C2. We showed that PFOA could enhance the transactivation of AR in reporter genes assays in which 5α-DHT metabolism was blocked by AKR1C2 inhibition in HeLa cells. Taken together, these data suggest PFOA has a role in disrupting androgen action through inhibiting AKR1C2. Our work identifies an EDC function for PFOA not previously revealed.

A highly sensitive electrochemical sensor based on poly(3-aminobenzoic acid)/graphene oxide-gold nanoparticles modified screen printed carbon electrode for paraquat detection

Herein, a modified screen printed carbon electrode (SPCE) based on a composite material, graphene oxide-gold nanoparticles (GO-AuNPs), and poly(3-aminobenzoic acid)(P3ABA) for the detection of paraquat (PQ) is introduced. The modified electrode was fabricated by drop casting of the GO-AuNPs, followed by electropolymerization of 3-aminobenzoic acid to achieve SPCE/GO-AuNPs/P3ABA. The morphology and microstructural characteristics of the modified electrodes were revealed by scanning electron microscopy (SEM) for each step of modification. The composite GO-AuNPs can provide high surface area and enhance electroconductivity of the electrode. In addition, the presence of negatively charged P3ABA notably improved PQ adsorption and electron transfer rate, which stimulate redox reaction on the modified electrode, thus improving the sensitivity of PQ analysis. The SPCE/GO-AuNPs/P3ABA offered a wide linear range of PQ determination (10-9-10-4 mol/L) and low limit of detection (LOD) of 0.45 × 10-9 mol/L or 0.116 µg/L, which is far below international safety regulations. The modified electrode showed minimum interference effect with percent recovery ranging from 96.5% to 116.1% after addition of other herbicides, pesticides, metal ions, and additives. The stability of the SPCE/GO-AuNPs/P3ABA was evaluated, and the results indicated negligible changes in the detection signal over 9 weeks. Moreover, this modified electrode was successfully implemented for PQ analysis in both natural and tapped water with high accuracy.

Behavioral, metabolic, and biochemical alterations caused by an acute stress event in a zebrafish larvae model

Animal welfare is a growing concern in aquaculture practices. Stress induced by handling or transportation can lead to negative impacts on the sector. Zebrafish has raised as an important aquaculture model, but still with few focus on its stress response in early life stages. Therefore, the objective of this study was to improve the evaluation of different markers of the stress response after a stress event in a zebrafish larvae model. Zebrafish larvae (96 hpf) were vortex-stimulated for 1 min at 200 rpm for acute stress induction. After 10 min, 1- and 4-h behavioral larvae outcomes and larvae were sampled to the following quantification: levels of cortisol, lactate, glucose and biochemical biomarkers (reactive oxygen species, superoxide dismutase, catalase, glutathione peroxidase, lipidic oxidation level and protein carbonylation, glutathione s-transferase, acetylcholinesterase, lactate dehydrogenase and ATPase), and the metabolic rate. The cortisol, glucose, and lactate levels had no alterations. At the behavioral level, an increase in the distance swam and in the speed was observed and the metabolic rate also increased according to the behavioral outcomes. The ATPase and GST activity showed a decrease in their activity, probably through osmoregulation changes related to the hypothetic adrenocorticotropic hormone downregulation. Overall, the acute vortex stimulation at low speed induced an early stress response independent of the HPI-cortisol pathway. In addition, this study shows zebrafish early life stages as a sensitive model to acute vortex stimulation, identifying altered parameters which can be used in future work to assess the effect on animal welfare in similar acute situations.

The preventive effectiveness of Crocus sativus extract in treating lung injuries caused by inhaled paraquat in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The herbicide paraquat (PQ) is highly toxic, capable of inducing severe lung inflammation and oxidative stress, resulting in lung fibrosis and respiratory failure. Previous research has demonstrated a range of pharmacological effects associated with Crocus sativus. L (Cs) through its anti-inflammatory, antioxidant and immunomodulatory properties. Pharmacological studies support the widespread use of Cs in traditional medicine to treat respiratory disorders such as coughs and asthma.

AIM OF STUDY

This study aimed to investigate the preventive impact of Cs extract and pioglitazone (Pio) on lung inflammation, oxidative stress, pathological alterations, and tracheal reactivity induced by inhaled PQ in rats as compared to dexamethasone (Dexa).

METHODS

The control (Ctrl) group of rats was administered with saline aerosol, while the remaining six groups received PQ aerosol eight times every other day. The six PQ exposure groups were treated daily during the exposure period to PQ with either; saline alone, low dose Cs, High dose Cs, Pio alone, Pio combined with low dose Cs, or Dexa of 16 days.

RESULTS

In the PQ group, the levels of superoxide dismutase (SOD), catalase (CAT), and thiol in the bronchoalveolar lavage fluid (BALF) were declined whereas, the levels of MDA, total and differential WBC, and lung tissue levels of tumor necrosis factor (TNF-α) and Interleukin 10 (IL-10), tracheal responsiveness (TR) to methacholine and lung pathological changes were enhanced. The measured variables showed significant improvement in all treated groups, except for a few variables in Cs (L). The combined Cs (L) + Pio showed higher effects than Cs (L) and Pio alone. For all comparisons, p values were <0.05 to <0.001.

CONCLUSIONS

The results showed preventive effect of Cs comparable to that of Dexa and the potential additive preventive capabilities of the Cs and Pio indicate that the involvement of the PPARγ receptor is implicated in the effects induced by Cs.

Evaluation of in-vitro antioxidant activity, acute oral toxicity, and pancreatic and hepatic protective effects of Aloe rubroviolacea flowers extract against CCl4 toxicity in a rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe rubroviolacea (Arabian Aloe) was widely cultured and commonly used in traditional medicine. Aloe species was highly recommended in folk medicine for abdominal pain, intestinal infection, intestinal colic, obesity, and gynaecological pain after childbirth.

AIM OF THE WORK

The present work aimed to conduct chemical profiling, in-vitro antioxidant activity, in-vivo oral acute toxicity study of A. rubroviolacea flowers ethanolic extract (ARFEE) along with exploring pancreatic and hepatic protective effects of ARFEE against carbon tetrachloride (CCl4) toxicity in a rat model. Molecular docking study of ARFEE and 3D structure activity relationship was also demonstrated to investigate the proposed antioxidant mechanism.

MATERIALS AND METHODS

The chemical composition was analyzed using gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC) techniques. Total phenolic and flavonoid contents in ARFEE were estimated by Folin-Ciocalteu and AlCl3 colorimetric methods, respectively. In-vitro antioxidant DPPH assay was performed using ascorbic acid as a reference standard. Moreover, In-vivo acute toxicity study using fixed doses of ARFEE (0.1, 0.5, 1, 2 and 3 g/kg orally) was conducted. CCl4 toxicity was induced by using a single dose of CCl4 (1 ml/kg, i.p.) on 5th day, silymarin (50 mg/kg/day, orally) as a standard and two different doses of ARFEE (250, 500 mg/kg, orally) daily for 5 days before CCl4 injection.

RESULTS

GC-MS analysis displayed the existence of 36 chemical compounds, the majority of which were fatty acids and their esters, in addition to phytosterols. The total phenolic content of ARFEE was 25.09 ± 1.65 mg of gallic acid equivalent/g extract dry weight (mg GAE/g DW), while the total flavonoid content was 17.48 ± 0.64 mg of quercetin equivalent/g extract dry weight (mg QE/g DW). Our results showed that the ARFEE had a potential in-vitro antioxidant activity as strong as ascorbic acid. No mortality or signs of toxicity were observed after ARFEE intake. Additionally, ARFEE ameliorated CCl4 toxicity on hepatic and pancreatic tissues. Molecular docking study resulted in potent promising natural compounds contained in ARFEE with anti-oxidant potential.

CONCLUSION

Based on oral safety, good anti-oxidant and pancreato- and hepato-protective activities of ARFEE against CCl4 toxicity, ARFEE is probably a potent agent for treatment of liver ailments.

Biocontrol activity of Kluyveromyces marxianus YG-4 against Penicillium expansum LPH9 on apples

Penicillium expansum (P. expansum), a widespread fungal pathogen, causes serious economic loss and public health concerns. The aim of this research is to investigate the antifungal effect of Kluyveromyces marxianus YG-4 (K. marxianus YG-4) against P. expansum and possible mechanism. The results showed that competition for nutrients and space, as well as the release of volatile organic compounds (VOCs), are the antifungal mechanisms. Citronellol may be the antifungal component of K. marxianus YG-4 VOCs based on GC-MS analysis. Further experiments had shown that citronellol inhibited the growth of P. expansum LPH9 by damaging the cell structure, disrupting the redox system, reducing antioxidant enzyme activity, and causing oxidative damage. K. marxianus YG-4, K. marxianus YG-4 VOCs and citronellol can effectively inhibit the spore germination of P. expansum on apples. The above results indicated that K. marxianus YG-4 had strong biocontrol activity and can be used as an excellent candidate strain for fruit preservation.

Application of the luminous bacterium Photobacterium phosphoreum for toxicity monitoring of selenite and its reduction to selenium(0) nanoparticles

Luminous marine bacteria are traditionally used as a bioassay due to the convenience and high rate of registering the intensity of their physiological function - luminescence. This study aimed to develop the application of Photobacterium phosphoreum in traditional and novel fields - toxicity monitoring and biotechnology. We demonstrated (1) effects of selenite ions on bioluminescence, and (2) biotransformation of selenite to selenium(0) in the form of nanoparticles. The effects of selenite (SeO32-) on the intensity of bacterial bioluminescence were studied, and its dependencies on exposure time and concentration of Na2SeO3 were analyzed. Bioluminescence activation and inhibition were revealed; dose-effect dependencies corresponded to the hormesis model. The toxicity of SeO32- was characterized by an effective concentration of 10-3 M. Effects of SeO32- on reactive oxygen species (ROS) in bacterial suspensions were studied. High positive correlations were found between the bioluminescence intensity and ROS content, which indicates the decisive role of ROS and associated redox processes in the bioeffects of selenite ions. Scanning and transmission electron microscopy revealed the presence of nano-structures in the bacteria exposed to selenite. The energy dispersion spectrum detected a high content of selenium in the nanoparticles. The particle size distribution depended on Na2SeO3 concentration; maxima of the distribution varied within 45-55 nm.

In vitro cyto- and geno-toxicity of asbestiform erionite from New Zealand

This work is an in vitro toxicity study of two asbestiform erionites from Kaipara and Gawler Downs in New Zealand. This study is the first, to the knowledge of the authors, to investigate the mechanisms that trigger adverse effects leading to carcinogenicity from New Zealand erionites. The effects induced by the erionite fibres from New Zealand were compared with those produced by positive (crocidolite) and negative (wollastonite) standards, and other erionite fibres described in the literature. The cytotoxicity/genotoxicity/inflammatory potential was determined by: (i) analysis of the cytotoxic potential by MTT tests on human cell lines mimicking primary cells making direct contact with fibres in the lungs, combined with apoptosis tests and cell membrane damage by fluorescence microscopy analyses; (ii) analysis of the genotoxic potential by quantification of DNA damage measuring double strand break foci by γ-H2AX nuclear staining in confocal microscopy analyses; (iii) analyses of the acute (24-72h) and early-chronic (7d) inflammatory effect by gene expression analyses of several cytokines, as well as of fibrotic and Epithelial to Mesenchymal transition (EMT) markers. The intensity of cell responses to these erionites are comparable to that of standard carcinogenic crocidolite, indicating that the two erionite fibres exhibit a significant acute toxic potential, with a particular alarming effect from the Gawler Downs sample from South Island. Our results confirm that the investigated erionites from New Zealand may represent an environmental hazard. However, further investigation is required to determine potential environmental exposure pathways by which erionite may become airborne and assess any environmental risks that may arise.

A comprehensive library of lifetime physiological equations for PBK models: Enhancing dietary exposure modeling with mercury as a case study

Dietary risk assessment of food contaminants requires a well-established understanding of the exposure in a heterogeneous population. There are many methods for estimating human exposure to food contaminants, such as intake calculations and internal biomarkers of exposure measured in individuals. However, those methods are expensive, partly invasive, and often provide a momentary exposure snapshot. Physiologically Based Kinetic (PBK) modelling is increasingly used to overcome those challenges that traditional human exposure methods encounter. Still, PBK models are often restricted to certain life stages (e.g., children, adolescents, adults). This study outlines a strategy for implementing nonlinear organ growths in age-specific PBK models to enhance dietary risk assessment from lifetime exposure. To this end, lifetime physiological equations calculating organ growth for both sexes were inventoried from literature and a library was established for 24 organs. We then assessed total lifelong mercury exposure via foodstuff by combining two existing age-specific PBK models for methylmercury (MeHg) and inorganic mercury (iHg) that simulated internal exposure to total mercury, the speciation typically measured in hair and urine. We implemented a set of physiological equations in the PBK model that fitted best the total mercury measured in individuals' organs, hair, and urine from heterogeneous populations. For refined dietary risk assessment, we ultimately estimated total mercury concentration in hair and urine based on i) maximum limits defined by the regulation for MeHg in seafood, ii) the health-based guidance values for MeHg and iHg, and iii) realistic intakes considering French demographic parameters and food consumption data. These exposure scenarios demonstrated that total mercury concentrations in hair and urine estimated from realistic intakes are below critical effect level measures at all ages. The result of this study is the creation of easily accessible tools in Excel and R that facilitate the implementation of physiological equations in Next Generation PBK models.

Review on activity-based detection of doping substances and growth promotors in biological matrices: do bioassays deserve a place in control programs?

BACKGROUND

Control programs such as anti-doping control and growth promotor residue surveillance programs are challenged by the emergence of designer drugs and the use of low-level drug cocktails. In order to cope with these challenges, the use of bioassays, measuring biological activity in a matrix, has been explored over the past two decades as a universal means to detect (combinations of) unknown drugs, regardless of their chemical structure.

RESULTS

This review compiles the experience on the use of activity-based assays to detect doping substances and growth promotors in biological matrices of humans (athletes) or live animals (race and/or food-producing animals). The aim is to learn from the scientific progress, going from initial research to the recent revival of this topic. Bioassay improvements and remaining limitations are discussed, along with a rational evaluation of possible applications of bioassays in control programs at their current functionality. Limitations include the possible interference by endogenous compounds and the challenge to detect metabolically activated (pro-)drugs. Nevertheless, successful validation of bioassays has been achieved, ensuring robust, reliable and valid results.

SIGNIFICANCE

We conclude by proposing three applications of bioassays that provide added-value to the current testing procedures: (i) characterization of compounds to provide indisputable proof of biological effects and to prioritize legislative (cf. expansion of bans) and research endeavors (cf. method development), (ii) bioassay-based screening of biological samples to direct intelligent sample storage, sample retesting and targeted athlete testing, (iii) bioassay-guided identification of drugs to overcome the challenges of suspicious peak selection, related to high-resolution techniques.

Association between World Trade Center disaster exposures and body mass index in community members enrolled at World Trade Center Environmental Health Center

Studies suggest that environmental disasters have a big impact on population health conditions including metabolic risk factors, such as obesity and hypertension. The World Trade Center (WTC) destruction from the 9/11 terrorist attack resulted in environmental exposures to community members (Survivors) with potential for metabolic effects. We now examine the impact of WTC exposure on Body Mass Index (BMI) using the data from 7136 adult participants enrolled in the WTC Environmental Health Center (EHC) from August 1, 2005, to December 31, 2022. We characterized WTC-related exposures by multiple approaches including acute dust-cloud exposure, occupational or residential exposures, and latent exposure patterns identified by synthesizing multiplex exposure questions using latent class analysis. Employing multivariable linear and quantile regressions for continuous BMI and ordered logistic regression for BMI categories, we found significant associations of BMI with WTC exposure categories or latent exposure patterns. For example, using exposure categories, compared to the group of local residents, local workers exhibited an average BMI increase of 1.71 kg/m2 with 95% confidence intervals (CI) of (1.33, 2.09), the rescue/recovery group had an increase of 3.13 kg/m2 (95% CI: 2.18, 4.08), the clean-up worker group had an increase of 0.75 kg/m2 (95% CI: 0.09, 1.40), and the other mixer group had an increase of 1.01 kg/m2 (95% CI: 0.43, 1.58). Furthermore, quantile regression analysis demonstrated that WTC exposures adversely affected the entire distribution of BMI in the WTC EHC Survivors, not merely the average. Our analysis also extended to blood pressure and hypertension, demonstrating statistically significant associations with WTC exposures. These outcomes highlight the intricate connection between WTC exposures and metabolic risk factors including BMI and blood pressure in the WTC Survivor population.

Evaluating human health risks from exposure to agricultural soil contaminants using one- and two-dimensional Monte Carlo simulations

The health and well-being of Indigenous Peoples are closely connected to the state of their lands. While natural soils are important for food security initiatives within these communities, they may also expose people to harmful contaminants. Consequently, this study - guided by Indigenous community members and leaders - evaluates the human health risks associated with contaminants in soils intended for agricultural purposes on Indigenous Peoples' lands in regions of Australia and Canada. Soil samples were collected from 47 sites in seven locations and analyzed for metals, metalloids, and organochlorine pesticides. Non-carcinogenic and carcinogenic risks were assessed for children, youths, and adults using one- and two-dimensional Monte Carlo simulations. The results indicate that there is a non-carcinogenic risk of exposure to lead (Pb) for children (HQ = 1.83) in Australia and an oral ingestion risk due to inorganic arsenic (As) for children (HQ = 1.05) in Newfoundland. Carcinogenic risks from As exposure were also identified for children (R = 1.68 × 10-5) and adults (R = 1.18 × 10-5) in Newfoundland from oral ingestion. However, no non-carcinogenic or carcinogenic risk from dermal exposure was found for all tested contaminants. The results indicate a potential need for targeted interventions, such as soil remediation, when and where possible, or community education, to reduce exposure risks.

Exploring the nephrotoxicity and molecular mechanisms of Di-2-ethylhexyl phthalate: A comprehensive review

Di-2-ethylhexyl phthalate (DEHP), a widely applied plasticizer in various products, can be absorbed into the human body through several channels and accumulate in the lungs, liver, testes, and kidneys, potentially impairing the function of these organs. Recently, the nephrotoxicity of DEHP has received heightened attention. Numerous epidemiologic findings have demonstrated that DEHP exposure may contribute to renal damage, leading to structural and functional abnormalities and exacerbating the progression of kidney disease. Recent research has discovered the mechanisms behind DEHP-induced nephrotoxicity may involve a variety of pathways, including apoptosis, autophagy, ferroptosis, oxidative stress, inflammation, DNA damage, and lipid metabolism disorders. This review discusses the impact of DEHP on kidney function and delves into the molecular mechanisms of nephrotoxicity mediated by DEHP in recent years. In addition, the review examines evidence for the antioxidant and anti-inflammatory capacities of lycopene, green tea polyphenols, and quercetin in ameliorating DEHP-induced renal injury is reviewed, providing a basis for further research.

Advance on the effects of algal carotenoids on inflammatory signaling pathways

The development of inflammation has an indispensable importance in the self-protection of the human body. However, over-inflammation may damage human health, and inflammatory pathways and inflammasomes have a significant impact on the onset of inflammation. Therefore, how to constrain the development of inflammation through inflammatory pathways or inflammasomes becomes a hot research issue. Carotenoids are a natural pigment and an active substance in algae, with anti-inflammatory and antioxidant effects. Many studies have shown that carotenoids have inhibitory effects on the inflammatory pathways and inflammasomes. In this review, we discussed the mechanism of carotenoids targeting those important inflammatory pathways and their effects on common inflammasome NLRP3 and inflammation-related diseases from the perspective of several inflammatory pathways, including p38 MAPK, IL-6/JAK/STAT3, and PI3K, with a focus on the targets and targeting effects of carotenoids on different inflammatory signaling pathways, and at last proposed possible anti-inflammatory targets.

Incorporating new approach methods (NAMs) data in dose-response assessments: The future is now!

Regulatory dose-response assessments traditionally rely on in vivo data and default assumptions. New Approach Methods (NAMs) present considerable opportunities to both augment traditional dose-response assessments and accelerate the evaluation of new/data-poor chemicals. This review aimed to determine the potential utilization of NAMs through a unified conceptual framework that compartmentalizes derivation of toxicity values into five sequential Key Dose-response Modules (KDMs): (1) point-of-departure (POD) determination, (2) test system-to-human (e.g. inter-species) toxicokinetics and (3) toxicodynamics, (4) human population (intra-species) variability in toxicodynamics, and (5) toxicokinetics. After using several "traditional" dose-response assessments to illustrate this framework, a review is presented where existing NAMs, including in silico, in vitro, and in vivo approaches, might be applied across KDMs. Further, the false dichotomy between "traditional" and NAMs-derived data sources is broken down by organizing dose-response assessments into a matrix where each KDM has Tiers of increasing precision and confidence: Tier 0: Default/generic values, Tier 1: Computational predictions, Tier 2: Surrogate measurements, and Tier 3: Direct measurements. These findings demonstrated that although many publications promote the use of NAMs in KDMs (1) for POD determination and (5) for human population toxicokinetics, the proposed matrix of KDMs and Tiers reveals additional immediate opportunities for NAMs to be integrated across other KDMs. Further, critical needs were identified for developing NAMs to improve in vitro dosimetry and quantify test system and human population toxicodynamics. Overall, broadening the integration of NAMs across the steps of dose-response assessment promises to yield higher throughput, less animal-dependent, and more science-based toxicity values for protecting human health.

Effects of contaminants and flooding on the physiology of harvested estuarine decapod crustaceans: A global review and meta-analysis

Contaminants are transported into estuaries during rainfall events, impacting the physiology of harvested species, and thereby threatening fisheries sustainability. Decapods are among the most economically important groups harvested from estuaries, but are at high risk of contaminant exposure. We conducted a systematic review and meta-analysis evaluating the physiological responses of harvested estuarine decapods to contaminants and flooding. A total of 138 research articles were identified, with global research efforts corresponding to the geographic distribution of crustacean harvesting. From these studies, 305 acute toxicity values for metals, polcyclic aromatic hydrocarbons (PAHs) and pesticide chemical classes were extracted and 341 sublethal effect sizes (log-response ratios; LnRRs) calculated using 91 physiological measures across seven response categories. At sublethal environmentally relevant concentrations, exposure to various metals, pesticide chemical classes and PAHs consistently elicited negative effects on decapod physiology (LnRR range: -0.67 to -0.07). Key physiological processes impacted by contaminant exposure included nutritional condition, osmoregulation, oxidative stress defences, acetylcholinesterase activity, metabolism and growth (LnRR range: -0.73 to -0.10), with a general trend for greater effects later in ontogeny. With new agricultural and industrial chemicals continually being marketed, our meta-analysis highlights the need for regulatory testing on harvested species prior to registration for use in catchment areas. Under future climatic variability, harvested estuarine decapods may be increasingly exposed to contaminants, with implications for fisheries and global food security.

The effects of photochemical aging and interactions with secondary organic aerosols on cellular toxicity of combustion particles

Fine particulate matter (PM2.5) is associated with numerous adverse health effects, including pulmonary and cardiovascular diseases and premature death. Significant contributors to ambient PM2.5 include combustion particles and secondary organic aerosols (SOA). Combustion particles enter the atmosphere and undergo an aging process that changes their shape and composition, but there is limited study on the health effects of combustion particle aging and interactions with SOA. This study aimed to understand how biological responses to combustion particles would be affected by atmospheric aging and interaction with anthropogenic SOA. Fresh combustion particles underwent photochemical aging in a potential aerosol mass (PAM) oxidation flow reactor and interacted with SOA produced by the oxidation of toluene vapor in the PAM reactor. Photochemical aging and SOA interactions lead to significant changes in the PAH content and oxidative potential of the particle. Photochemical aging and SOA interactions also affected the biological responses, such as the inflammatory response and CYP1A1 induction of the particles in monoculture and coculture cells. These findings highlight the significance of photochemical aging and SOA interactions on the composition and cellular responses of combustion particles.

Chronic exposure to low concentration of diflubenzuron and pyriproxyfen induces brain oxidative stress and inflammation and alters locomotion in zebrafish (Danio rerio)

Diflubenzuron (DFB1) and pyriproxyfen (PPF) are pesticides widely used in agriculture and urban environments to control insect actions. The aim of this study was to evaluate the effects of chronic 30-day exposure to DFB (0.025 and 0.125 mg/L) and PPF (0.379 and 0.758 mg/L) on the behavior of juvenile zebrafish (Danio rerio). Fish were exposed to insecticides from early stage (4 h post fertilization) to 30 days post fertilization (dpf). At 45 dpf, fish were evaluated in the novel tank test, social behavior test, and mirror aggressive test. Brain gene expression related to oxidative stress and inflammation was also evaluated. DFB reduced locomotor parameters in the novel tank and aggression tests, while it induced to hyperactivity in the social behavior test. PPF reduced anxiety-like behavior, measured by the time spent in risky areas of the novel tank, and reduced aggression against the mirror image. There was a significant reduction in mRNA levels of the nfe2l2 gene (∼0.54 fold downregulated) and increase in levels of cat (PPF ∼1.8 fold change), gsr (PPF ∼1.5 fold change), gpx1a (PPF ∼1.6 and DFB 1.1 fold change), tnf-α (PPF 1.9 and DFB 2.2 fold change), and il-6 (PPF ∼1.2 and DFB 2.3 fold change). These endpoints are indicative of the threatening effects of insecticides to aquatic organisms and the need for alternative methods to control pests by using less harmful and safer substances for animal and human well-being, as well as for the environment.

Life table analysis and RNA-Seq reveal hormesis and transgenerational effects of deltamethrin on Aphis gossypii

BACKGROUND

Deltamethrin, as a highly effective and broad-spectrum insecticide, has been widely used for agricultural pest control such as Aphis gossypii worldwide. Increasing evidence has shown that despite great economic benefits brought by it, deltamethrin has also non-negligible side effects. However, the potential risks and related molecular mechanisms remain largely unclear.

RESULTS

Herein, the life table parameters and transcriptome sequencing analyses of the four successive aphid generations were performed to investigate the hormesis and transgenerational effects of deltamethrin on A. gossypii. The life table analysis showed that although the exposure of G0 aphid to 30% lethal concentration (LC30) deltamethrin significantly reduced the net reproduction rate (R0), intrinsic rate of increase (r), and fecundity of G0, but it significantly enhanced the R0 and fecundity of subsequent two generations (G1 and G2) of A. gossypii. Moreover, transcriptomic analyses showed that the signaling pathways related to posttranscriptional regulation (spliceosome), protein processing, longevity regulating, and cell proliferation (DNA replication, homologous recombination and non-homologous end-joining) were significantly up-regulated in G1 or G2 under LC30 deltamethrin treatment. Additionally, we also found that the deltamethrin-sulfoxaflor rotation of G0 and G1 still induced reproductive stimulation, but the reproductive stimulation induced by insecticides rotation treatment was significantly lower than that in the deltamethrin exposure alone.

CONCLUSION

Our study demonstrates that sublethal concentrations of deltamethrin significantly enhanced the offspring fecundity of cotton aphid. In addition, our study also reveals the transcriptional response mechanism of hormesis-induced fecundity increase, providing valuable reference for optimizing the application of deltamethrin in integrated pest management. © 2024 Society of Chemical Industry.

Adverse Outcome Pathways Mechanistically Describing Hepatotoxicity

Adverse outcome pathways (AOPs) describe toxicological processes from a dynamic perspective by linking a molecular initiating event to a specific adverse outcome via a series of key events and key event relationships. In the field of computational toxicology, AOPs can potentially facilitate the design and development of in silico prediction models for hazard identification. Various AOPs have been introduced for several types of hepatotoxicity, such as steatosis, cholestasis, fibrosis, and liver cancer. This chapter provides an overview of AOPs on hepatotoxicity, including their development, assessment, and applications in toxicology.

Characterization of ornithine decarboxylase with histidine decarboxylase activity in natural histidine decarboxylase gene deletion Enterobacter hormaechei RH3

Histamine is predominantly produced in sausages via the decarboxylation of histidine by bacteria. Furthermore, histamine-producing bacteria usually possess the enzyme histidine decarboxylase (hdc). Enterobacter hormaechei RH3 isolated from sausages exhibited significant levels of histamine production despite the absence of hdc. In this study, we elucidated the previously unidentified mechanism underlying histamine production by RH3. We identified an enzyme, NehdX-772, exhibiting the hdc activity from the cell lysate supernatant of RH3, which was annotated as ornithine decarboxylase. The optimal activity of NehdX-772 was recorded at 35 °C and pH 6.0, and it could tolerate a salt concentration of 2.5% (w/v) NaCl. Moreover, artificial inoculation revealed that NehdX-772 was synthesized at significant levels in sausages, leading to an increase in histamine levels. The discovery of NehdX-772 explains the underlying mechanism of histamine production by RH3 and can be applied to decrease histamine production in sausages.

Time-trends of blood lead levels from 2020 to 2023 in pregnant and breastfeeding women from Adjara, Georgia-A birth registry-based study

BACKGROUND

In response to substantial lead exposure, the autonomous republic of Adjara in Georgia initiated complementary blood lead level (BLL) testing for pregnant women as part of their antenatal care services in 2020.

OBJECTIVES

To study the background BLLs in pregnant and breastfeeding women in Adjara and explore the time-trends of BLLs from September 2020 to July 2023.

METHODS

We used data on BLLs during pregnancy or postpartum from the lead screening program in Adjara, combined with data from the Georgian Birth Registry, totaling 9,510 women. To study the temporal changes in BLLs, we used independent samples t-tests and chi-square tests.

RESULTS

In 2020, the mean (standard deviation [SD]) BLL was 8.8 (5.4) μg/dL, declining annually by 1.0-2.2 μg/dL to reach 3.6 (2.5) μg/dL in 2023. The prevalence of pregnant women with BLLs ≥3.5, ≥5.0, and ≥10.0 μg/dL also decreased from 2020 to 2023. Specifically, 21.2% of women in their first trimester had BLLs ≥10 μg/dL in 2020, compared with 2.3% in 2023. Similarly, 73.5% had BLLs ≥5.0 μg/dL in 2020, which declined to 20.4% in 2023. Lastly, 89.1% had BLLs ≥3.5 μg/dL in 2020, decreasing to 38.6% in 2023.

DISCUSSION

In 2023, nearly 40% of women in their first trimester had BLLs of ≥3.5 μg/dL, a level considered the reference value in the United States (US) and corresponding to the 97.5th percentile among US children. From 2020 to 2023, the mean BLL in pregnant women decreased by 59%, accompanied by a considerable decline in the prevalence of women with BLLs ≥3.5, ≥5.0, and ≥10.0 μg/dL. Despite the encouraging downward trend in BLLs throughout the study period, our data indicate that a considerable number of fetuses continue to be exposed to harmful levels of lead and that lead exposure remains a significant public health challenge in Adjara.

Temporal and geographic variability of bisphenol levels in humans: A systematic review and meta-analysis of international biomonitoring data

INTRODUCTION

Bisphenols are endocrine-disrupting chemicals known to contribute to chronic disease across the lifespan. With increased awareness of their health effects, changes in regulation and health behaviors have contributed to reductions in urinary bisphenol A (BPA) levels in the United States, Canada, and Europe. However, global trends in bisphenols outside these regions, especially bisphenol S (BPS) exposure, have been less studied.

AIM

We examine trends in urinary BPA and BPS concentration in non-occupationally exposed populations, where representative data at a country level is unavailable.

METHODS

We systematically reviewed studies published between 2000 and 2023 that included urinary bisphenol concentrations. We examined BPA and BPS concentration changes by sampling year, controlling for region, age, and pregnancy status, with and without a quadratic term and geometric mean, via mixed-effects meta-regression models with a random intercept and sensitivity analysis. We identified heterogeneity using Cochran's Q-statistic, I2 index, and funnel plots.

RESULTS

The final analytic sample consisted of 164 studies. We observed positive non-linear associations between time and BPA concentration internationally (beta: 0.02 ng/mL/year2, 95% CI: [0.01, 0.03]) and in Eastern and Pacific Asia (beta: 0.03 ng/mL/year2, 95% CI: [0.02, 0.05]). We also observed non-linear associations of time with both BPA and BPS concentrations in the Middle East and South Asia (beta: 0.13 ng/mL/year2, 95% CI: [0.01, 0.25] and beta: 0.29 ng/mL/year2, 95% CI: [-0.50, -0.08], respectively). In the sensitivity analyses excluding studies with geometric or arithmetic mean values, each displayed significant shifts from the main findings with some consistent outcomes occurring internationally and/or in specific regions. Heterogeneity was high across studies, suggesting possible bias in our estimations.

CONCLUSIONS

Our findings provide evidence for concern about increasing population exposure to BPA and BPS. Further studies estimating attributable disease burden and costs at regional and global levels are warranted to show these chemicals' impact on population health and economies.

Suppression of Hippocampal Neurogenesis and Oligodendrocyte Maturation Similar to Developmental Hypothyroidism by Maternal Exposure of Rats to Ammonium Perchlorate, a Gunpowder Raw Material and Known Environmental Contaminant

The environmental contaminant perchlorate raises concern for hypothyroidism-related brain disorders in children. This study investigated the effects of developmental perchlorate exposure on hippocampal neurogenesis and oligodendrocyte (OL) development. Pregnant Sprague-Dawley rats were administered with ammonium perchlorate (AP) in drinking water at concentrations of 0 (control), 300, and 1000 ppm from gestation day 6 until weaning [postnatal day (PND) 21]. On PND 21, offspring displayed decreased serum triiodothyronine and thyroxine concentrations at 1000 ppm and thyroid follicular epithelial cell hyperplasia at ≥300 ppm (accompanying increased proliferation activity at 1000 ppm). Hippocampal neurogenesis indicated suppressed proliferation of neurogenic cells at ≥300 ppm, causing decreases in type-1 neural stem cells (NSCs) and type-2a neural progenitor cells. In addition, an increase of SST+ GABAergic interneurons and decreasing trend for ARC+ granule cells were observed at 1000 ppm. CNPase+ mature OLs were decreased in number in the dentate gyrus hilus at ≥300 ppm. At PND 77, thyroid changes had disappeared; however, the decrease of type-1 NSCs and increase of SST+ interneurons persisted, CCK+ interneurons were increased, and white matter tissue area was decreased at 1000 ppm. Obtained results suggest an induction of hypothyroidism causing suppressed hippocampal neurogenesis (targeting early neurogenic processes and decreased synaptic plasticity of granule cells involving ameliorative interneuron responses) and suppressed OL maturation during the weaning period. In adulthood, suppression of neurogenesis continued, and white matter hypoplasia was evident. Observed brain changes were similar to those caused by developmental hypothyroidism, suggesting that AP-induced developmental neurotoxicity was due to hypothyroidism.

Integration of MUTZ-Langerhans cells into a 3D full-thickness skin equivalent and influences of serum reduction and undefined medium supplements on differentiation

The MUTZ-3 cell line is a surrogate for Langerhans cells (LCs) employed in New Approach Methodologies for assessing the skin sensitizing potential of chemicals. However, MUTZ-3 cells must first be differentiated to achieve the LC-typical phenotype. As all protocols use high fetal calf serum (FCS) concentrations, we aimed at reducing, or even replacing FCS, while maintaining MUTZ-LC characteristics. Additionally, we assessed the impact of the poorly defined 5637-conditioned medium (5637CM) on MUTZ-LC differentiation. With reducing the FCS content by 75 %, the desired differentiation status was achieved after 7 instead of 14 days, identified by elevated CD207 and CD1a expression. Culture with Ultroser G, a synthetic surrogate for FCS, resulted in an insufficient number of MUTZ-LCs. 5 % FCS-differentiated MUTZ-LCs could be activated with DNCB, an extreme sensitizer, as demonstrated by increased CD83 expression. 5637CM did not affect MUTZ-LC differentiation and is therefore not needed as a supplement. For their intended role in an immunocompetent skin model to assess the sensitizing potential of chemicals, MUTZ-LCs were successfully integrated into the Phenion® Full-Thickness skin model, as demonstrated by CD1a expression. These results are important steps towards medium standardization and the generation of an immunocompetent skin model according to the 3R principles.

Terminal deoxynucleotidyl transferase-mediated CRISPR sensing platform for simple and point-of-care detection of cobalt pollution

The excessive use of cobalt in various chemical industries and arbitrary discharge of industrial wastewater have led to increased cobalt pollution in soil and water resources, increasing the risk of human exposure to high concentrations of cobalt and necessitating an urgent need for on-site monitoring platform for cobalt pollution. In this study, the terminal deoxynucleotidyl transferase (TdT)-CRISPR platform has been developed. In this platform, cobalt as a cofactor of TdT, can significantly improve the tailing efficiency of TdT-mediated extension. Therefore, when cobalt is present, the detection probe can be extended with poly(T) tails through the TdT-mediated extension, which can be subsequently served as the DNA activator for Cas12a, leading to the cleavage of fluorescence reporter molecules and triggering turn-on fluorescence signals. Consequently, this dual amplification sensing strategy of TdT-CRISPR platform demonstrated exceptional sensitivity (0.83 nM) and high specificity for cobalt over other ions. Furthermore, the method was successfully employed for the detection of cobalt in tap water and river samples. CRISPR-lateral flow assays (CRISPR-LFAs) were evaluated in this study for the simple and point-of-care detection of cobalt pollution. The assays are capable of detecting cobalt concentrations as low as 50 nM, which is significantly lower than the environmental standards of 16.9 μM, through strip analysis with the naked eye. These results commonly suggest that the TdT-CRISPR platform holds significant promise for monitoring cobalt pollution, providing a robust and sensitive solution for on-site detection and contributing to the mitigation of cobalt contamination risks in environmental matrices.

Faecal Volatile Organic Compounds to Detect Colorectal Neoplasia in Lynch Syndrome-A Prospective Longitudinal Multicentre Study

BACKGROUND

Non-invasive biomarkers may reduce post-colonoscopy colorectal cancer (CRC) rates and colonoscopy overuse in Lynch syndrome. Unlike faecal immunochemical test (FIT), faecal volatile organic compounds (VOCs) may accurately detect both advanced and non-advanced colorectal neoplasia.

AIM

The aim of this study was to evaluate the potential of faecal VOCs-separately and with FIT-to guide optimal colonoscopy intervals in Lynch syndrome.

METHODS

Prospective longitudinal multicentre study in which individuals with Lynch syndrome collected faeces before and after high-quality surveillance colonoscopy. VOC-patterns were analysed using field asymmetric ion mobility spectrometry (FAIMS) and gas chromatography-ion mobility spectrometry (GC-IMS) followed by machine learning pipelines, and combined with FIT at 2.55 μg Hb/g faeces. Gas chromatography time-of-flight mass spectrometry analysed individual VOC abundance.

RESULTS

Among 200 included individuals (57% female, median 51 years), 62 had relevant neoplasia at colonoscopy: 3 CRC, 6 advanced adenoma (AA), 3 advanced serrated lesion (ASL), and 50 non-advanced adenoma (NAA). Respective sensitivity and negative predictive value for CRC and AA (and also ASL in case of FAIMS) were 100% and 100% using FAIMS (54% specificity), and 89% and 99% using GC-IMS (58% specificity). Respective sensitivity and specificity for any relevant neoplasia were 88% and 44% (FAIMS) and 84% and 28% (GC-IMS); accuracy did not significantly improve upon VOC-FIT. VOC-patterns differed before and after polypectomy (AUC 0.70). NAA showed decreased faecal abundance of butanal, 2-oxohexane, dimethyldisulphide and dimethyltrisulphide.

CONCLUSIONS

In Lynch syndrome, faecal VOCs may be a promising strategy for postponing colonoscopy and for follow-up after polypectomy. Our results serve as a stepping stone for large validation studies.

TRIAL REGISTRATION

NL8749.

An evaluation of trends for mesothelioma mortality in American women: Addressing the content of a recent Morbidity and Mortality Weekly Report (MMWR)

Mesothelioma is a fatal disease that has historically been associated with exposure to airborne asbestos. Because occupational asbestos exposures dropped dramatically in the late 1960s and early 1970s, far fewer cases of mesothelioma today are due to these fibers but, instead, are usually a result of the aging process or genetic predisposition. In May of 2022, a Morbidity and Mortality Weekly Report (MMWR) was issued by the Centers for Disease Control and Prevention (CDC) regarding malignant mesothelioma incidence in women from 1999 to 2020. While this MMWR alerted citizens to the continued presence of the disease, after reading this article one might have thought that the CDC was suggesting that the disease was increasing in women due to asbestos exposures (which it is not). In the present analysis, we investigate several factors related to the interpretation of epidemiological data for mesothelioma, including the role of asbestos as a risk factor over time. The authors conducted a review of the scientific community's understanding of mesothelioma incidence and asbestos exposures amongst women, as well as an investigation of the methods and references in the MMWR article. Although various articles have recently discussed the incidence of both peritoneal and pleural mesothelioma in women, it is fortunate that the age-adjusted rates for mesothelioma have remained flat (neither increased nor decreased significantly) in women for the past 50 years. Incredibly few women in the U. S. have had appreciable cumulative exposures to any type of asbestos (chrysotile, amosite, or crocidolite) in the workplace or from the ambient environment, especially since about 1965-1970. In this paper, we highlight six factors that should be considered when evaluating the incidence of mesothelioma amongst American women in the current era. Without sufficient consideration of these factors, improper conclusions have been drawn over the past several years.

Influence of temperature changes on oxidative stress and antioxidant defense system in the bay scallop, Argopecten irradians

In this study, we aimed to understand the effects of changes in temperature on biochemical and molecular responses associated with the antioxidant defense system in the bay scallop, Argopecten irradians. We measured the contents of H2O2 and malondialdehyde (MDA), as well as the activities of antioxidant enzymes (e.g., glutathione S-transferase [GST], superoxide dismutase [SOD], and catalase [CAT]), and the regulation of stress-related genes (e.g., GST, SOD, CAT, and heat shock protein 70 [HSP70]). In addition, total antioxidant capacity (TAC) was examined in scallops exposed to different temperatures. A. irradians showed high levels of H2O2 and MDA in response to acute thermal stress (48 and 72 h of exposure). Temperature changes also led to a significant increase in antioxidant enzyme activity and mRNA expression levels in A. irradians. Interestingly, the TAC increased in response to acute thermal stress (28 °C) for up to 12 h and decreased thereafter. The oxidative stress induced by high temperatures could not be alleviated by an increase in levels of antioxidant enzymes, such as GST, SOD, and CAT, resulting in high levels of H2O2 and MDA and low levels of TAC. In addition, significant changes (P < 0.05) in HSP70 levels were observed in response to changes in temperature, suggesting that HSP70 played an important role in the heat tolerance of A. irradians. In conclusion, A. irradians exhibits a greater degree of oxidative stress responses in high-temperature environments than that in low-temperature environments. Overall, these findings indicate that temperature changes lead to oxidative stress, resulting in cellular damage and activation of the antioxidant defense system in bay scallops. Further experiments are required to elucidate other antioxidants and fully understand the redox system in A. irradians.

Valifenalate-induced non-adverse thyroid changes via adaptive induction of uridine 5'-diphospho-glucuronosyltransferase (UGT) in the liver of dogs and rats but not humans

Some rat and dog toxicology studies with the fungicide valifenalate showed minimal, non-adverse thyroid changes, mostly above the maximum tolerated dose, and concomitantly with liver effects. This publication describes their mode of action (MOA), combining in vivo and new approach methodologies (NAMs), in a weight of evidence approach. Data demonstrate a MOA of liver enzyme induction via nuclear receptor CAR/PXR activation, increased thyroxine (T4) metabolism and elevated thyroid stimulating hormone (TSH) level, leading to thyroid follicular cell hypertrophy and increased thyroid weight. Non-human relevance of the MOA was demonstrated in in vitro cross species assays in rat, dog and human hepatocytes. Increased gene expression and activity of cytochrome P450s (CYPs) and uridine 5'-diphospho-glucuronosyltransferases (UGTs) were observed in rat and dog hepatocytes exposed to valifenalate, with increased T4 clearance and/or T4 glucuronidation/T4-UGT activity. Therefore, a causal relationship between increased liver enzyme induction and thyroid effects in dogs and rats is concluded. Rat hepatocytes were most sensitive, while valifenalate did not increase T4-UGT activity above 2-fold of vehicle control or T4 glucuronidation and T4 clearance in human hepatocytes. Consequently, valifenalate exposure in humans is unlikely to lead to decreased T4 levels, and subsequent thyroid and developmental neurotoxicity effects. Alternative human-relevant thyroid MOAs were excluded, i.e. inhibition of deiodinases (DIO), thyroperoxidase (TPO) or the sodium iodide symporter (NIS). Due to known species differences in thyroid homeostasis between humans and laboratory animals and, importantly, based on the presented data, this liver enzyme mediated MOA is considered not relevant for human hazard assessment.

Research advance of occupational exposure risks and toxic effects of semiconductor nanomaterials

In recent years, semiconductor nanomaterials, as one of the most promising and applied classes of engineered nanomaterials, have been widely used in industries such as photovoltaics, electronic devices, and biomedicine. However, occupational exposure is unavoidable during the production, use, and disposal stages of products containing these materials, thus posing potential health risks to workers. The intricacies of the work environment present challenges in obtaining comprehensive data on such exposure. Consequently, there remains a significant gap in understanding the exposure risks and toxic effects associated with semiconductor nanomaterials. This paper provides an overview of the current classification and applications of typical semiconductor nanomaterials. It also delves into the existing state of occupational exposure, methodologies for exposure assessment, and prevailing occupational exposure limits. Furthermore, relevant epidemiological studies are examined. Subsequently, the review scrutinizes the toxicity of semiconductor nanomaterials concerning target organ toxicity, toxicity mechanisms, and influencing factors. The aim of this review is to lay the groundwork for enhancing the assessment of occupational exposure to semiconductor nanomaterials, optimizing occupational exposure limits, and promoting environmentally sustainable development practices in this domain.

Metals in honey from bees as a proxy for environmental contamination in the United States

This is the first large bio-surveillance study examining the contents and geographic variation of metals of public health concern-arsenic (As), lead (Pb), cadmium (Cd), nickel (Ni), chromium (Cr), and cobalt (Co)-in honey samples collected across the United States. Metal concentrations were measured using ICP-MS, and the spatial distribution pattern of these contaminants was evaluated using statistical and GIS tools. The mean (highest) values (in μg/kg) were 3.8 (170) for As, 8.0 (451) for Pb, and 0.75 (8.1) for Cd. These values, as well as the mean (highest) concentrations of 29.5 (516) for Ni, 14.3 (166) for Co, and 19.6 (11) for Cr, were markedly lower than global averages reported in other countries. The study identified distinct geographic patterns of honey contamination; particularly high As levels were found in northwestern states, while high Co was measured in the southeast. Health risk calculations based on the hazard quotient (HQ) and hazard index (HI) were below 1 for a daily tablespoon (21g) of honey consumption, indicating no adverse health concerns for children and adults, and all samples fell below the 1.0 × 10-6 threshold for carcinogenic risk from As. The variation in metal concentrations found in samples from different states may reflect the influence of air, water, or soil pollution, as well as differential accumulation across plant species, and the distinct geographic clustering of As and Co warrants further investigation to determine the sources of these metals and to assess public health risks, particularly for As, a well-known carcinogen. In sum, this initial study provides baseline values of metal concentrations in honey that can be useful for monitoring future pollution trends, identifying target areas where reductions of emissions or remediation efforts are most critical, and facilitating discovery in environmental exposures (the exposome) and health research, including on cancer and cardiovascular diseases.

Enhancing reliability of embryo-fetal developmental toxicity studies: A proposed design of replicate studies

BACKGROUND

This report addresses the reliability of results from rat Embryo-Fetal Developmental Toxicity (EFDT) studies. Recent literature discusses the roles of reproducibility, replicability, and other influences on scientific reliability. Reproducibility is a re-analysis of the original data, while replicability addresses the same question with a separate study of some type. Concordance of rat and rabbit studies has been addressed previously, but replication of single-species EFDT studies was not found in the literature. A modest modification of the rat study is therefore proposed to assess replicability and possibly enhance reliability.

METHODS

Regulatory guidelines were consulted and relevant literature was identified through online searches.

RESULTS

Each replicate EFDT (r-EFDT) study in rats would consist of half the mated females of the definitive study. Studies would start at the same or different times in one testing facility. Separate shipments of animals (non-littermates) are required. All other procedures would be protocol-driven. The micro- and macro-environments of the animals would be held as constant as possible. Justification, design options, and interpretation methods are discussed.

CONCLUSION

Besides adding reliability, other benefits include reduced animal usage, and potentially reduced cost and time to final reports. By reducing the need for repeated studies due to questionable results, this modified study is viewed as a more efficient use of costly resources. The r-EFDT study design could easily be adapted to assess replicability of rabbit EFDT and some general toxicity studies. Future replicate studies are needed to critically evaluate replicability and the overall impact on study reliability.

Evaluation of the efficacy of diosmin and chrysin against tau-fluvalinate exposure in rats

Tau-fluvalinate is a type 2 pyrethroid insecticide. Diosmin and chrysin are flavonoids with antioxidant and anti-apoptotic effects. Role of diosmin and chrysin against infavorable toxic effects caused by tau-fluvalinate and the underlying mechanisms of these effects were investigated. Six groups were formed and diosmin, chrysin, tau-fluvalinate, tau-fluvalinate + diosmin and tau-fluvalinate + chrysin were administered orally to rats at a dose of 20 mg/kg.bw except for the control group, once a day for 21 days, respectively. Tau-fluvalinate elevated MDA and NO levels while diminishing the activities of antioxidant enzymes (SOD, CAT, GSH-Px, GR, GST, G6PD) and GSH levels in the majority of the analyzed blood and tissues, statistically significant. Serum triglyceride, cholesterol, total protein and albumin levels as well as LDH and PChE activities decreased. Conversely, serum creatinine, AST, ALT and ALP levels/activities increased. Elevated protein levels of caspase 3, caspase 9, p53 and Bax and decreased protein levels of Bcl-2 were observed in the liver. There were negative changes in body/some organ weights. Diosmin and chrysin administration resulted in a marked recovery in tau-fluvalinate-induced toxic effects, but this improvement was not complete. These flavonoids may be considered as promising potential therapeutic options to alleviate the adverse effects associated with tau-fluvalinate intoxication.

Comparative transcriptomic analysis and volatile compound characterization of Aspergillus tubingensis and Penicillium oxalicum during their infestation of Japonica rice

Volatile organic compounds (VOCs), a byproduct of mold metabolism, have garnered increasing interest because the VOCs can be used to detect food early contamination. So far, the use of VOCs as indicators of rice mildew, specifically caused by Aspergillus tubingensis and Penicillium oxalicum, and the mechanisms of their generation are not well investigated. This study examines the VOCs produced by these molds during paddy storage, utilizing headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). We further elucidate the mechanisms underlying the formation of these VOCs through a comparative transcriptomic analysis. The VOCs characteristic to A. tubingensis and P. oxalicum, identified with a VIP value > 1 in the partial least squares discriminant analysis (PLS-DA) model, are primarily alkenes. Our transcriptome analysis uncovers key metabolic pathways in both molds, including energy metabolism and pathways related to volatile substance formation, and identifies differentially expressed genes associated with alkane and alcohol formation.

Embryonal exposure to 4-methylbenzylidene camphor induces reproduction impairment in adult zebrafish (Danio rerio)

This study investigated how early exposure to xenobiotics can lead to disease in adulthood, which is challenging for toxicologists. We employed a 'cradle to grave' approach using zebrafish (Danio rerio) embryos exposed to 4-methylbenzylidene camphor (4-MBC), a commonly used organic UV filter. Molecular docking and simulation studies confirmed the predictive toxicity and stable interaction of 4-MBC with androgen and estrogen receptors, with binding energies of -9.28 and -9.01 kcal/mol, respectively. Exposure to 4-MBC at 5, 50, and 500 μg/L concentrations resulted in significantly altered transcriptional and translational responses of ar, esr1, and vtg1 genes in embryos at 120 h post-fertilization (hpf). The exposure induced a non-monotonic dose-response pattern (NMDR), a characteristic feature of endocrine-disrupting chemicals. Additionally, a significant decrease in fertilization was observed in adults. Although fecundity was not affected in inter- and intra-breeding performances, developmental deformities were observed in F1 progenies with impaired survival at 10 days post-fertilization. The findings of this study show that embryonic exposure to 4-MBC is likely to induce reproductive and transgenerational toxicity in D. rerio and exhibit endocrine disruption in aquatic non-target organisms. This work is the first to elucidate the low-level long-term effects of 4-MBC from the embryonic stage to adulthood.

Bisphenol S exposure promotes stemness of triple-negative breast cancer cells via regulating Gli1-mediated Sonic hedgehog pathway

Bisphenol S (BPS), one of the most common alternatives for bisphenol A (BPA), has been implied to increase the risk of breast cancer. Triple-negative breast cancer (TNBC) is a highly aggressive type of breast cancer with a poor prognosis. However, the association between BPS and TNBC remains unclear. Cancer stem cells (CSCs) have a crucial role in breast cancer initiation, metastasis, and recurrence. Here, we proposed that BPS, equivalent to the human internal exposure and the environmental concentrations, enhanced CSC-like properties by upregulating sphere formation, self-renewal, the percentage of CD44+/CD24- cells, and the expression of CSC markers. Moreover, BPS promoted the migration, invasion, and epithelial-mesenchymal transition (EMT) in TNBC cells. Mechanistically, BPS activated the Sonic Hedgehog (SHH) signaling pathway in TNBC cells. Molecular docking analysis further showed that BPS upregulated SHH signaling pathway via directly binding Gli1 protein. Furthermore, inhibitor of SHH pathway or Gli1 siRNA attenuated the promoting effects of BPS on stemness, invasion, and migration of TNBC cells. In summary, our data firstly provide evidence that environmentally relevant BPS concentration treatment significantly enhanced TNBC malignant phenotype by activating the Sonic Hedgehog/Gli1 signaling pathway, raising high concerns about the potential population biology hazards of BPS.

Gut microbiota combined with metabolome dissects Fluorene-9-bisphenol exposure-induced male reproductive toxicity

A major alternative to bisphenol A (BPA), fluorene-9-bisphenol (BHPF) has been shown to cause multiorgan toxicity. However, its reproductive toxicity and the underlying biological mechanism remain largely unknown. Recently, changes in the gut microbiota and metablome caused by environmental contaminant exposure and their potential impact on male reproductive health have been of great concern. Therefore, we aimed to elucidate the underlying mechanism of BHPF-related fertility impairment by integrating metabolome and microbiome analysis. In the present study, we showed that BHPF exposure caused testicular dysfunction with impaired spermatogenesis and disrupted steroid hormone synthesis. Mechanistically, altered gut microbiota and metabolites were revealed by 16S rDNA sequencing and untargeted metabolomics analysis. Subsequent multi-omics combination analysis revealed a strong correlation between altered microbiota and lipid metabolites. We also found a strong relationship between lipid metabolites and sperm parameters such as sperm concentration, sperm motility, etc. Most importantly, these findings provide new insights into the mechanistic scenario underlying BHPF-induced fertility toxicity, that disrupted lipid metabolism caused by gut microbiota dysbiosis may be a reason for reproductive impairment caused by BHPF exposure.

Volatilome of the maize phytopathogenic fungus Fusarium verticillioides: potential applications in diagnosis and biocontrol

BACKGROUND

Fusarium verticillioides is a maize fungal phytopathogen and a producer of volatile organic compounds (VOCs) and fumonisin B1 (FB1). Our aim was to study the volatilome, conidial production, ergosterol and FB1 biosynthesis in maize cultures over a 30-day incubation period (5, 10, 15, 20, 25, 30 days post inoculation [DPI]). The effect of pure VOCs on the same parameters was then evaluated to study their potential role as biocontrol agents.

RESULTS

In total, 91 VOCs were detected, with volatile profiles being more similar between 5 and 10 DPI compared with 15, 20, 25 and 30 DPI. Ergosterol content increased steadily with incubation time, and three growth stages were identified: a lag phase (0 to 15 DPI), an exponential phase (15 to 20 DPI) and a stationary phase (20 to 30 DPI). The maximum concentration of FB1 was detected at 25 (0.030 μg FB1/μg ergosterol) and 30 DPI (0.037 μg FB1/μg ergosterol), whereas conidial production showed a maximum value at 15 DPI (4.3 ± 0.2 × 105 conidia/μg ergosterol). Regarding pure VOCs, minimal inhibitory concentration values ranged from 0.3 mm for 4-hexen-3-one to 7.4 mm for 2-undecanone. Pure VOCs reduced radial growth, conidial production and ergosterol and FB1 biosynthesis.

CONCLUSIONS

The marked resemblance between VOC profiles at 5 and 10 DPI suggests that they could act as early indicators of fungal contamination, particularly 4-ethylguaiacol, 4-ethyl-2-methoxyanisole, heptanol and heptyl acetate. On the other hand, their role as inhibitors of fungal growth and FB1 biosynthesis prove their great potential as safer alternatives to control phytopathogenic fungi. © 2024 Society of Chemical Industry.