Methylmercury (MeHg) is a potent neurotoxin and can lead to neurodegeneration in animals and humans. Fecal microbiota transplantation has been found to regulate the neurotoxicity of MeHg in rats. This study investigated the therapeutic potential of orally-given commercially-available probiotics (primarily Bifidobacterium and Lactobacillus acidophilus) against MeHg-poisoning in rats. It was found that probiotics intervention promoted the demethylation of MeHg in the liver and intestines, accompanied by upregulation of demethylating bacteria such as Desulfovibrionaceae and Geobacteraceae. It also reshaped the gut microbiota, significantly increasing beneficial short-chain fatty acids(SCFA)-producing bacteria like Ruminococcaceae and Lachnospiraceae. SCFA, amino acids and bile acids were found increased in feces. The expression of pro-inflammatory cytokines TNF-α and IL-6, and up-regulated IL-10 in the gut, serum and brain was found reduced, showing the decreased inflammation. Besides, the capability of spatial learning, memory, and motor coordination of MeHg-poisoned rats was improved as showed through Morris water maze test. Histologically, H&E staining revealed neatly arranged neurons with reduced nuclear condensation, while Nissl staining showed increased Nissl bodies and restored neuronal activity. In all, this study provides a simple and potentially translational strategy for MeHg-poisoning and sheds lights for the treatment of neurodegenerative diseases.

Although 6PPD-quinone (6PPD-Q), a pervasive tire-derived contaminant, poses emerging health risks, its systemic toxicity mechanisms remain poorly understood; effective noninvasive monitoring tools are still lacking. We combined ultrasensitive photoinduced associative ionization time-of-flight mass spectrometry (PAI-TOFMS) with multi-organ transcriptomics and serum metabolomics to mechanistically assess 6PPD-Q-induced toxicity in mice. We identified a robust and highly sensitive five-analyte breath panel associated with organ-level molecular perturbations. Mechanistic integration suggests that acetaldehyde is associated with a hepatic metabolic reprogramming syndrome that dysregulates steroid biosynthesis and with oxidative stress-driven transcriptional signatures of genotoxic stress. Dimethyl disulfide is associated with perturbation of systemic sulfur metabolism and correlates with hepatic glutathione depletion and redox imbalance. In the kidneys, trimethylamine is associated with compromised clearance and metabolic stagnation, potentially related to PPAR signaling suppression. In the lungs, monochloramine and 3-buten-2-one are associated with immune infiltration and membrane lipid peroxidation, respectively. By establishing a cohesive "breath-blood-organ" framework, we demonstrate that these exhaled signatures are consistent with internal tissue pathology. This study elucidates the multi-organ toxicity of 6PPD-Q via a metabolic-genotoxic axis and provides a validated noninvasive toolkit for future environmental epidemiology and population health screening.

Neurodegenerative diseases bring heavy burden to our society. Methylmercury (MeHg) is a potent neurotoxin and causes neurodegenerative diseases like Minamata Disease. Therefore, finding ways to combat MeHg-induced neurodegeneration may shed light on the treatment of neurodegenerative diseases. This study investigated the efficacy of bismuth selenide nanoparticles (Bi2Se3NPs, nBS) in treating MeHg-induced neurodegeneration. MeHg-poisoned rats were orally given nBS (4 mg/kg) every other day for 21 days and then sacrificed. It was found that nBS improved neurobehavioral performance, alleviated hippocampus damage and intestinal barrier damage, reduced Hg accumulation, and promoted MeHg demethylation in MeHg-poisoned rats. In addition, nBS up-regulated the abundance of gut microbes such as Faecalibacterium, Bifidobacterium and Akkermansiaceae, and increased the levels of butyric acid in feces while reduced the concentration of isobutyric acid in the brains. At the same time, nBS reduced the secretion of inflammatory factors IL-6 and TNF-α in the brains, guts and serum, and regulated AHR/IDO expression in the guts and brains. In all, nBS treatment improved the health status of MeHg-poisoned rats through enhancing Hg excretion and MeHg demethylation, reshaping gut microbiota, and reducing neuroinflammation. These findings suggested that nBS supplementation is a promising approach to treat MeHg-induced neurodegeneration, which may shed lights on the treatment of neurodegenerative diseases.

Approximately 367 million metric tons of plastic were produced globally in 2020, and it is projected that the global plastic waste will reach around 12,000 metric tons by 2050. Plastic waste can be fragmented into nanoplastics (NPs). Despite their widespread presence in the environment and even within the human body, the long-term risks of NPs to plants, animals, and humans remain poorly understood. This study investigated the life-long impacts of nano polyethylene terephthalate (nPET) on rice (Oryza sativa L.), which is a staple food for a significant portion of the global population. We found that nPET exposure at environmentally relevant concentrations negatively affected rice growth, compromising grain quality and yield. nPET exposure disrupted the metallome, interfered with chlorophyll synthesis, and induced oxidative stress in rice plants. Additionally, nPET exposure influenced soil health, as evidenced by increased soil organic matter (SOM) during the tillering and flowering stages. The soil microbial community were significantly perturbed, with distinct β-diversity observed between nPET-exposed and control soils, including variations in species abundance at the phylum and family levels. Moreover, nPET exposure affected soil microbiota involved in carbon, nitrogen, and sulfur cycles, with specific species capable of degrading PET being identified. Overall, exposure to environmentally relevant concentrations of nPET led to reduced rice grain yield and compromised soil health, characterized by perturbed metallome and soil microbiome. Therefore, effective management of NPs in soils is urgently needed to ensure food safety and soil health.

BackgroundMercury, as a global heavy metal pollutant, poses a serious threat to human health. The toxicity of mercury depends on its chemical form. Distinguishing the forms of mercury in the environment is of great significance for mercury management and reducing human mercury exposure risks. ObjectiveTo establish a non-targeted metallomics method based on synchrotron radiation X-ray fluorescence (SRXRF) spectroscopy combined with machine learning to screen inorganic mercury (IHg) or methylmercury (MeHg) exposed rice plants. MethodsRice seeds were exposed to ultra-pure water (control group), 0.1 mg·L−1 IHg (IHg group) or MeHg (MeHg group) solutions, respectively. After germination, the seedlings were cultured for 21 d, and rice leaves were collected, dried, weighed, and pressed. The content of metallome in rice leaves was determined by SRXRF. Machine learning models including soft independent modeling cluster analysis (SIMCA), partial least squares discriminant analysis (PLS-DA), and logistic regression (LR) were used to classify the SRXRF full spectra of different groups and find the best model to distinguish rice exposed to IHg or MeHg. Besides, characteristic elements were selected as input parameters to optimize the model by improving computing speed and reducing model calculation. ResultsThe SRXRF spectral intensities of the control group, IHg group, and MeHg group were different, indicating that exposure to IHg and MeHg can interfere the homeostasis of metallome in rice leaves. The results of principal component analysis (PCA) of SRXRF spectra showed that the control group could be well distinguished from the mercury exposed groups, but the IHg group and the MeHg group were mostly overlapped. The accuracy rates of the three models (PLS-DA, SIMCA, and LR) were higher than 98% for the training set, higher than 95% for the validation set, and higher than 94% for the cross-validation set. Besides, the accuracy of the LR model was higher than that of the PLS-DA model and the SIMCA model. Furthermore, the accuracy was 92.05% when using characteristic elements K, Ca, Mn, Fe, and Zn selected by LR to distinguish the IHg group and the MeHg group. Compared with the full spectra model, although the prediction accuracy of the characteristic spectral model decreased, the input parameters of the model decreased by 99.51%, and precision, recall, and F1 score were above 84.48%, indicating that the model could distinguish rice exposed to different mercury forms. ConclusionNon-targeted metallomics method based on SRXRF and machine learning can be applied for high-throughput screening of rice exposed to different forms of mercury and thus decrease the risks of people being exposed to mercury.

Microplastics (MPs) and nanoplastics (NPs) are global pollutants with emerging concerns. Methods to predict and screen their toxicity are crucial. Elemental dyshomeostasis can be used to assess toxicity of environmental pollutants. Non-targeted metallomics, combining synchrotron radiation X-ray fluorescence (SRXRF) and machine learning, has successfully differentiated cancer patients from healthy individuals. The whole idea of this work is to screen the phytotoxicity of nano polyethylene terephthalate (nPET) and micro polyethylene terephthalate (mPET) through non-targeted metallomics with SRXRF and deep learning algorithms. Firstly, Seed germination, seedling growth, photosynthetic changes, and antioxidant activity were used to evaluate the toxicity of mPET and nPET. It was showed that nPET, at 10 mg/L, was more toxic to rice seedlings, inhibiting growth and impairing chlorophyll content, MDA content, and SOD activity compared to mPET. Then, rice seedling leaves exposed to nPET or mPET was examined with SRXRF, and the SRXRF data was differentiated with deep learning algorithms. It was showed that the one-dimensional convolutional neural network (1D-CNN) model achieved 98.99% accuracy without data preprocessing in screening mPET and nPET exposure. In all, non-targeted metallomics with SRXRF and 1D-CNN can effectively screen the exposure and phytotoxicity of nPET/mPET and potentially other emerging pollutants. Further research is needed to assess the phytotoxicity of different types of MPs/NPs using non-targeted metallomics.

Methylmercury (MeHg) can cause devastating neurotoxicity in animals and human beings. Gut microbiota dysbiosis has been found in MeHg-poisoned animals. Fecal microbiota transplantation (FMT) has been shown to improve clinical outcomes in a variety of diseases such as epilepsy, amyotrophic lateral sclerosis (ALS) and autism. The aim of this study was to investigate the effects of FMT on MeHg-poisoned rats. FMT treatment was applied to MeHg-poisoned rats for 14 days. The neurobehavior, weight changes, dopamine (DA), the total Hg and MeHg level were evaluated. Besides, the gut microbiota and metabolites change in feces were also checked. It was found that FMT helped weight gain, alleviated the neurological disorders, enhanced fecal mercury excretion and MeHg demethylation, reconstructed gut microbiome and promoted the production of gut-brain axis related-metabolites in MeHg-poisoned rats. This study elaborates on the therapeutic efficacy of FMT in treating of MeHg-poisoned rats, which sheds lights on the treatment of neurological diseases like Minamata Disease and even Parkinson's Disease.

As a global pollutant, mercury (Hg), especially methylmercury (MeHg) has strong neurotoxicity and poses a great threat to human health. Accumulating evidence suggests that the gut microbiota plays an important role in mediating the neurotoxicity of Hg. For example, Hg in the gut can undergo biotransformation by gut microbiota, including the demethylation of MeHg and the methylation of elemental mercury (Hg0) and inorganic mercury(iHg) to MeHg. On the other hand, MeHg can disrupt the interaction between the gut and the brain by changing the community structure and function of the gut microbiota and the metabolites related to neurological activities. Therefore, understanding the interaction between gut microbiota in the mediating of the neurotoxicity of different mercury species will help further understand the mechanism of the neurotoxicity of Hg. In this chapter, a systematic summary of the mediating effects of gut microbiota on the neurotoxicity of Hg, especially MeHg was presented. The future aspect on the study of gut microbiota against the neurotoxicity of Hg was also put forward.

Mercury (Hg) is harmful to the environment and human health. The gut plays important roles as the biological, chemical, mechanical, and immune barriers in animals and human beings. It has been known that Hg can be absorbed and methylated/demethylated in the gut, on the other hand, the impacts of Hg to the gut (especially the gut microbiota) is less studied. This review paper summarizes the impacts of inorganic Hg (IHg) and methyl Hg (MeHg) on gut barriers and the extraintestinal effects (damage to other organs such as the liver and brain). Both IHg and MeHg were found to cause intestinal microbial disorders, abnormal metabolites production, tight junction damage, and immune responses in the gut. The damage to the gut also contributed to the extraintestinal effects like the hepatotoxicity by IHg and the neurotoxicity by MeHg. In all, it is proposed that the gut should be considered as an important target tissue of Hg exposure, and the regulation of gut microbiota may have the potential for the prevention and control of the toxicity of Hg.

Mercury (Hg) is a global pollutant that threatens the environment and human health. As a major producer, emitter and consumer of Hg, China is currently taking different measures to curb mercury pollution in accordance with the requirements of the Minamata Convention on Mercury. Blood Hg can reflect the human body's recent exposure to Hg. This review summarized the temporal changes in blood Hg concentrations in newborns and the general public in China from 1980 s to 2020 s. It was shown that the blood Hg concentrations of newborns showed the downward trend, although it was not significant. The general public Hg concentrations showed a trend of first increase and then decrease trend. Most of the cord blood Hg and venous blood Hg concentrations in China were lower than the USEPA reference concentration of 5.8 µg/L. Since low-dose prenatal Hg exposure can affect fetal and neonatal development, continuous attention needs to be paid to reduce maternal and neonatal Hg exposure. The information provided in this review may lay a basis for the effectiveness evaluation on the implementation of Minamata Convention on Mercury.

Cardamine violifolia belongs to the Brassicaceae family and is a selenium (Se) hyperaccumulator found in Enshi, China. In this study, C. violifolia was found to accumulate mercury (Hg) in its roots and aboveground parts at concentrations up to 6000 μg/g. In the seedling and mature stages, the bioaccumulation factors (BAFS) of Hg reached 1.8-223, while the translocation factor (TF) for Hg reached 1.5. We observed a significant positive correlation between THg concentrations in plant tissues and those in the soil (r2 = 0.71-0.84). Synchrotron radiation X-ray fluorescence with focused X-ray (μ-SRXRF) showed that Hg was translocated from the roots to shoots through the vascular bundle and was transported through the leaf veins in leaves. Transmission electron microscopy showed that root cells were more tolerant to Hg than leaf cells. These findings provide insights into the mechanisms of Hg hyperaccumulation in C. violifolia. Overall, we demonstrated that C. violifolia is a promising Hg hyperaccumulator that may be used for phytoremediating Hg-contaminated farmlands.

Cardamine violifolia is a Se hyperaccumulator found in Enshi, China. In this study, spatial metallomics was applied to visualize the distribution and speciation of Se in a single seed of C. violifolia. It was found that Se reached 1729.89 ± 28.14 mg/kg and the main Se species were SeCys and SeMet in bulk seeds. Further in situ study on a single seed found that the methylated Se species located mostly in the episperm. This is the first visualized evidence of the in situ distribution of methylated Se species in the seeds of C. violifolia. In all, spatial metallomics finds a preferable accumulation of methylated Se species in the seed coat, which deepens the understanding of the tolerance of Se by C. violifolia. The protocol applied in this study may also be used for the understanding of the tolerance of heavy metals/metalloids in other hyperaccumulators.

Polyethylene terephthalate (PET) are widely used in our daily life while they may be broken to smaller fractions as nano-sized PET (nPET) in the environment. The toxicity of nPET is still less studied. This work first evaluated the LD50 of different size of nPET (200 nm, S-nPET; 700 nm, B-nPET) in mice, then studied the health effects of single exposure to S/B-nPET at 200 mg/kg bw for 30 days. It was found that the LD50 was 266 mg/kg bw for S-nPET and 523 mg/kg bw for B-nPET, respectively, showing a size-dependent effect. S-nPET caused weight loss, cyst, intestinal obstruction, organ damage and mortality (40%), and perturbed gut microbiome and metabolome especially lipid metabolism, such as upregulated cholesterol, glycocholic, propionic acid, niacinamide, ectoine and xanthine, and downregulated arachidonic acid, anserine, histamine, while B-nPET did not. Serological analysis found S-nPET brought more lipid metabolic immune and neurological damage than B-nPET, confirming the size-dependent effect. To the best of our knowledge, this is the first report on the systematic toxicity of nPET to mice. Further studies are warranted for life-long effects of nPET. The protocol applied in this work may also be used for the study of the health effects of other plastics.

Abstract Background Methylmercury (MeHg) can bring devastating neurotoxicity to animals and human beings. Gut microbiota has been found to demethylate MeHg while MeHg exposure was found to destroy the diversity and abundance of gut microbiota. Besides, some neurotransmitters such as GABA, glutamate and other metabolites were altered due to MeHg exposure. Fecal microbiota transplantation (FMT) has been successfully applied to treat a series of diseases like Tourette syndrome, irritable bowel syndrome, necrotizing enterocolitis and to treat ulcerative coliti. The objective of this study was to investigate the effects of FMT in treating MeHg-poisoned rats. Results: It was found that FMT for 14 days promoted body weight gain, enhanced demethylation of MeHg and increased fecal excretion of Hg in MeHg-poisoned rats. Furthermore, the gut microbial bacteria associated with demethylation, such as sulfate-reducing bacteria were restored and some metabolites related to neuroactivity through gut-brain axis were increased after FMT, there is also repair of brain derived neurotrophic factor(BDNF)-related factor levels in the intestine, brain and serum. Conclusions: In all, it was showed that FMT can be a effective way in treating MeHg-poisoned rats through the reconstruction of gut microbiota, especially the bacteria that are associated with the demethylation of MeHg. Furthermore, the modulation of metabolites that are related to gut-brain axis after FMT also contributed to the treating of MeHg-poisoning. This study provides a novel way to treat MeHg-poisoning, which may contribute to the health promotion of mercury exposed population and shed lights on the treatment of other neurological diseases like Parkinson’s disease.

Arsenic (As) exposure in humans is primarily caused through food and drinking water. Iron (Fe) is one of the most common element of the human and can influence the toxicity and bioavailability of As. However, information on the interaction between As and Fe when present together is limited. In this study, the interaction effects of Fe(III) (0, 3, and 10 mg/L) and As (As(III) at 0, 0.05, 0.1 mg/L, and As(V) at 0, 0.1, and 2 mg/L, respectively) on their absorption and bioavailability in Caco-2 cells were analyzed. As(III) absorption significantly decreased with the addition of Fe, while Fe absorption significantly increased. Compared with 0.1 mg/L As(III) addition alone, 3 and 10 mg/L Fe(III) addition significantly reduced the As(III) absorption by 8.6 and 11 μg/L, respectively. The absorption of As and Fe(III) and the bioavailability of Fe(III) significantly increased with the addition of As(III/V). Compared with 10 mg/L Fe(III) alone, the absorption of As(III) was significantly increased by 1 and 1.3 mg/L with 0.05 and 0.1 mg/L As(III) addition, respectively. Furthermore, the absorption and bioavailability of Fe(III) were significantly increased by 1.2 mg/L and 8% and 1.2 mg/L and 8.2%, respectively, after adding 0.1 and 2 mg/L As(V).

Dietary calcium (Ca) intake can alleviate fluoride (F) induced fluorosis to maintain bone health. However, it is unclear whether calcium supplements can reduce the oral bioavailability of F present in contaminated soils. Here we evaluated the effects of Ca supplements on F bioavailability in three soils using an in vitro method (Physi-ologically Based Extraction Test) and an in vivo mouse model. Seven Ca salts, commonly used in calcium sup-plements, significantly reduced the F bioaccessibility in the gastric and small intestinal phases. Particularly for Ca phosphate at 150 mg Ca supplementation, F bioaccessibility in the small intestinal phase was reduced from 35.1-38.8% to 0.7-1.9% where soluble F concentrations were less than 1 mg/L. Overall, the eight Ca tablets tested in this study showed greater efficiency at decreasing F solubility. The in vitro bioaccessibility after Ca supplementation was consistent with the relative bioavailability of F. As supported by X-ray photoelectron spectroscopy, a possible mechanism is that freed F can be bound by Ca to form insoluble CaF2 and exchanged with OH groups from Al/Fe hydroxide to strongly adsorb F. These findings provide evidence of Ca supple-mentation in reducing health risks associated soil F exposure.

Mercury (Hg) is a persistent and toxic metal while mercury selenide (HgSe) is generally considered as the environmental sink of Hg in its biogeochemical cycle. Recent studies found nano-sized HgSe (nano-HgSe) could be transformed by certain bacteria. This raises safety concerns about the application of selenium (Se) to curb Hg contamination in farmlands. Therefore, hydroponic experiments were performed in which rice plants were cultured with different concentrations of nano-HgSe and micro-sized HgSe (micro-HgSe) to explore their bioavailability and toxicity. It was found that both nano-HgSe and micro-HgSe did not affect the germination of rice seeds but affected the growth of rice seedlings. However, nano-HgSe could be more readily absorbed by roots and transferred to the aboveground parts compared to micro-HgSe. The highest Hg and Se levels were found to be 5255.67 ± 2496.14 μg/g and 1743.75 ± 61.87 μg/g, respectively in roots when exposed to 5000 mg/L nano-HgSe. Besides, small portion (1.2%) of methylmercury (MeHg) to total Hg was found accumulated in rice stem when exposed to 100 mg/L nano-HgSe, suggesting that nano-HgSe could be decomposed. Furthermore, nano-HgSe exposure brought oxidative damage to rice with decreased chlorophyll content and GSH-Px activity. In all, nano-HgSe was found to be more absorbable, transportable and methylated in rice plant compared to micro-HgSe. This suggests that although Se application in Hg contaminated farmland is an effective way to reduce the bioavailability of Hg, the risk of the possible remobilization of HgSe should not be neglected. Besides, the finding that nano-HgSe can act as an environmental source of Hg for plants deepens the understanding of biogeochemical cycle of Hg. More works are required to study the factors affecting the formation of nano-HgSe in the environment and the mechanisms of Hg methylation in rice plants after exposure to nano-HgSe.

金属组学是综合研究生命体内(特别是细胞内)自由或络合的全部金属原子的分布、含量、化学种态及其功能的一门学科,而大科学装置为金属组学研究提供了强有力的工具.首先介绍了金属组学发展简史,然后介绍了基于大科学装置的同步辐射技术、中子技术、质子技术及缪子技术等,最后概述了基于大科学装置的空间金属组学、单细胞/单颗粒金属组学的应用示例.基于大科学装置的中子活化技术(NAA)、X-射线荧光光谱(XRF).及质子激发X射线谱(PIXE)等技术是开展非原位空间金属组学研究的有力手段,而XRF、PIXE及缪子X射线荧光谱(MXA)为开展原位空间金属组学提供了有力工具,特别是基于XRF的技术,其空间分辨率可低至10 nm级别,是开展原位单细胞/单颗粒金属组学的利器.新一代同步辐射光源、质子源及缪子源将为空间金属组学、特别是时空金属组学研究提供更强有力工具.