Allergen protease-activated stress granule assembly and gasdermin D fragmentation control interleukin-33 secretion.

Interleukin-33 (IL-33), an epithelial cell-derived cytokine that responds rapidly to environmental insult, has a critical role in initiating airway inflammatory diseases. However, the molecular mechanism underlying IL-33 secretion following allergen exposure is not clear. Here, we found that two cell events were fundamental for IL-33 secretion after exposure to allergens. First, stress granule assembly activated by allergens licensed the nuclear-cytoplasmic transport of IL-33, but not the secretion of IL-33. Second, a neo-form murine amino-terminal p40 fragment gasdermin D (Gsdmd), whose generation was independent of inflammatory caspase-1 and caspase-11, dominated cytosolic secretion of IL-33 by forming pores in the cell membrane. Either the blockade of stress granule assembly or the abolishment of p40 production through amino acid mutation of residues 309-313 (ELRQQ) could efficiently prevent the release of IL-33 in murine epithelial cells. Our findings indicated that targeting stress granule disassembly and Gsdmd fragmentation could reduce IL-33-dependent allergic airway inflammation.

ECM1 is an essential factor for the determination of M1 macrophage polarization in IBD in response to LPS stimulation.

Inflammatory bowel disease (IBD) comprises chronic relapsing disorders of the gastrointestinal tract characterized pathologically by intestinal inflammation and epithelial injury. Here, we uncover a function of extracellular matrix protein 1 (ECM1) in promoting the pathogenesis of human and mouse IBD. ECM1 was highly expressed in macrophages, particularly tissue-infiltrated macrophages under inflammatory conditions, and ECM1 expression was significantly induced during IBD progression. The macrophage-specific knockout of ECM1 resulted in increased arginase 1 (ARG1) expression and impaired polarization into the M1 macrophage phenotype after lipopolysaccharide (LPS) treatment. A mechanistic study showed that ECM1 can regulate M1 macrophage polarization through the granulocyte-macrophage colony-stimulating factor/STAT5 signaling pathway. Pathological changes in mice with dextran sodium sulfate-induced IBD were alleviated by the specific knockout of the ECM1 gene in macrophages. Taken together, our findings show that ECM1 has an important function in promoting M1 macrophage polarization, which is critical for controlling inflammation and tissue repair in the intestine.

Enrichment mechanisms of Mo in soil in the karst region Guangxi, China.

Soils developed in karst regions have naturally high background values of molybdenum (Mo) due to geological factors. However, the enrichment mechanism of Mo in these soils are not fully understood, making it challenging to assess their ecological risk and utilize Mo-rich land resources. To shed light on this issue, this study collected and analyzed data from the 1:50,000 geochemical survey in Guangxi, including 536,503 sets of soil data and 3043 sets of rock data, as well as 40 sets of carbonate rock-soil from typical karst regions. The results showed that soil Mo enrichment is highly correlated with the distribution of carbonate rocks in karst regions. The carbonate rocks in these regions contain Mo ranging from 0.03 to 1.06 mg·kg-1 (with a mean of 0.22 mg·kg-1). In comparison, the soil Mo derived from carbonate rocks can reach up to 6.00 mg·kg-1 (with a mean of 2.75 mg·kg-1), representing an average enrichment of soil Mo that is 24 times higher compared to the carbonate parent rock. The enrichment of soil Mo in karst regions is primarily controlled by secondary enrichment during the weathering process of carbonate. During the insoluble residue accumulation process, the dissolution of carbonate leads to a dramatic reduction in bedrock volume, and the adsorption of clay minerals and Fe minerals in insoluble residues plays an essential role in Mo enrichment during these stages. During the soil-forming stage of the insoluble residue, most Mo leaches into the water body due to the mineral transformation of insoluble residue. Consequently, as Fe-Mn nodules in soils become more enriched with increasing weathering intensity, some Mo is absorbed and passivated by iron and manganese oxides (hydroxides). Accordingly, the contribution of Fe-Mn nodules and the degree of leaching were closely related to the enrichment of soil Mo in karst regions. This study provides insights into the enrichment mechanisms of Mo in soils developed in karst regions, which will help to evaluate their ecological risk in these environments.

Thrombin cleaves IL-33 and modulates IL-33-activated allergic lung inflammation.

BACKGROUND: Organisms have orchestrated coagulation and immune systems. Although a link between inflammation and haemostasis has been reported in asthma, the interaction mechanism has not been completely elucidated. Here, we investigated the direct link between the mammalian immune and coagulation systems. METHODS: Mice were administered protease or antigens intranasally to induce airway inflammation with or without thrombin inhibitors treatment. The effects of thrombin and its inhibitors on interleukin (IL)-33 were investigated both in vivo and in vitro. Peripheral blood mononuclear cells (PBMCs) and plasma from asthma patients are collected to verify the correlation between thrombin and group 2 innate lymphocytes (ILC2s). RESULTS: Low-molecular-weight heparin (LMWH, an indirect inhibitor of thrombin) restrained both papain- and fungus-induced type 2 immune responses in mice by inhibiting IL-33 cleavage. Upon examining the potential thrombin protease consensus sites, we found that IL-33 was directly cleaved by thrombin at specific amino acids (R48 and R106) to generate a mature form of IL-33 with potent biological activity. In addition, we found that bivalirudin TFA (a direct inhibitor of thrombin) inhibited a variety of type 2 inflammatory responses, such as those in house dust mite (HDM)- and ovalbumin (OVA)-mediated pulmonary inflammation models. We found that plasma thrombin-antithrombin complex (TATc) levels in asthma patients were positively associated with the number and function of IL-33-responder group 2 innate lymphocytes (ILC2s) among peripheral blood mononuclear cells (PBMCs) from asthma patients. CONCLUSION: The data suggested that thrombin inhibitors administration could be effective in treating lung inflammation by regulating ILC2s via IL-33 maturation, indicating that targeting thrombin is a potential way to treat allergic diseases.

Exploring the Risk Thresholds of Soil Heavy Metals in Carbonate and Non-carbonate Rock Areas: The Case of Qianjiang District in Chongqing, China.

To determine whether the national soil heavy metal standards (GB 15618-2018) are applicable to some carbonate and non-carbonate zones in Southwest China, rice and rhizosphere soil samples were collected in Chongqing and analyzed for heavy metal contents, pH, and other chemical parameters. In addition, regression analysis was also used to predict the risk threshold of soil heavy metals. The Cd risk screening value in GB 15618-2018 was strict for alkaline soils (pH > 7.5) as compared to those revealed in carbonate and non-carbonate areas, while the calculated pollution threshold for Cd in acidic soils (pH ≤ 5.5) in the non-carbonate area was lower than that in GB 15618-2018. Therefore, to improve the applicability of the evaluation results, a soil-crop system evaluation is recommended.

PKD2 gene variants in Chinese patients with autosomal dominant polycystic kidney disease.

PKD2 gene variants account for 4.5% to 20% of patients with autosomal dominant polycystic kidney disease (ADPKD). Little is known about the clinical characteristics of PKD2 variants in Chinese patients with ADPKD. Herein, we performed a comprehensive search for variants of PKD2 gene in 44 Chinese ADPKD pedigrees and a total of 37 variants were identified. Of these 37 variants, 18 were nonsense variants, 10 frameshift variants, 4 missense variants, and 5 splice site variants. 11/37 variants were detected for the first time. The median age at diagnosis was 30.5 years, and positive family history was detected in 77.27% patients, liver cysts in 68.18%, hypertension in 45.45%, nephrolithiasis in 31.82%, macro-hematuria in 22.73%, and proteinuria in 13.63%. The level of estimated glomerular filtration rate in 8/39 patients were blow 60 ml/min/1.73m2 . 11/17 patients were classified as rapid progression by Mayo Clinic classification. The end stage renal disease (ESRD) events were reported in 9/22 pedigrees, and the presence of nephrolithiasis and macro-hematuria were significantly associated with ESRD in the pedigrees with PKD2 variants. The identified variants and clinical features will facilitate the early diagnosis and prognosis prediction in Chinese ADPKD patients with PKD2 variants.

NIS-promoted three-component reaction of 3-oxo-3-arylpropanenitriles with arylsulfonyl hydrazides.

A new three-component reaction of 3-oxo-3-arylpropanenitriles with arylsulfonyl hydrazides has been established, and an expanded inventory of 3-aryl-4-(arylthio)-1H-pyrazol-5-amines is synthesized by sequential cyclization and sulfenylation reactions under the action of NIS. In addition to the attractive features of multicomponent reactions, the protocol presents broad substrate scope, good functional group tolerance and mild reaction conditions. The utility of this procedure is further established by gram-scale synthesis as well as the diversified transformations of the products to useful compounds.

Atypical extraventricular neurocytoma: A case report.

Atypical extraventricular neurocytoma (EVN) is a rare condition characterized by diffuse tumor cell hyperplasia, increased neovascularization, increased necrosis, and aggressive characteristics. A case of a 25-year old man who presented with atypical EVN in his left parietal - occipital flaps is reported. Magnetic resonance imaging (MRI) revealed a well-defined globular mass with heterogeneous signals in the left parietal lobe, and mild perilesional edema. After left parietal craniotomy and tumor excision, pathologic examination of the resected tissue revealed that the lesion was localized mainly in the white matter and imbued with tumor cells possessing round hyperchromatic nuclei with perinuclear halos and increased microvascular proliferation. The patient underwent radiotherapy at 21st postoperative day. Over the past 26 months, the patient has been regularly followed up, and so far no neurologic deficits have been observed. The latest MRI showed that the tumor bed was stable with slight peritumoral edema. The results of clinical, histopathological and immunohistochemical examinations indicate that atypical EVN is a rare neoplasm with unique radiographic and pathologic characteristics. It possesses more aggressive properties than typical EVN.

miR-133a-3p suppresses cell proliferation, migration, and invasion and promotes apoptosis in esophageal squamous cell carcinoma.

OBJECTIVE: This study aimed to investigate the expression levels of miR-133a-3p and collagen type I α 1 (COL1A1) in esophageal squamous cell carcinoma (ESCC) to find out the relationship between miR-133a-3p and COL1A1 and their influence on ESCC propagation, migration, invasion, and apoptosis. METHODS: The messenger RNA expression levels of miR-133a-3p and COL1A1 in ESCC were detected by quantitative reverse-transcription polymerase chain reaction. The expression of COL1A1 protein was examined via western blot analysis and immunohistochemistry assay. Cell propagation and apoptosis were, respectively, confirmed by CCK-8 and flow cytometry assay, whereas cell mobility and invasiveness were analyzed by wound healing assay and transwell assay. The targeted relationship between miR-133a-3p and COL1A1 was validated by the dual luciferase reporter assay. The tumor xenograft model was constructed to further verify the impact of miR-133a-3p on esophageal squamous tumor growth and COL1A1 expression in vivo. RESULTS: miR-133a-3p was found low-expressed whereas COL1A1 was highly expressed in esophageal squamous cancer tissue and cells. The expression of miR-133a-3p was negatively correlated with COL1A1 expression. The dual luciferase reporter gene assay confirmed that miR-133a-3p directly targeted COL1A1 and suppressed its expression. Cell Counting Kit-8 assay, transwell assay, and flow cytometry analysis demonstrated that COL1A1 promoted ESCC propagation and invasion and suppressed cell apoptosis, whereas miR-133a-3p reversed such adverse effects by regulating COL1A1. CONCLUSIONS: miR-133a-3p inhibited the cell propagation, invasion, and migration and facilitated apoptosis in ESCC by targeting COL1A1.

Risk of subsequent cancer among pediatric, adult and elderly patients following a primary diagnosis of glioblastoma multiforme: a population-based study of the SEER database.

Purpose/aim of the study: Our objective was to determine the risk of a subsequent malignancy in patients with glioblastoma multiforme (GBM). MATERIALS AND METHODS: Data of patients with a primary diagnosis of GBM were extracted from the Surveillance, Epidemiology, and End Results database. Patients were divided into three age groups: pediatric, ≤19 years of age; adult, 20-59 years; elderly, ≥60 years. Outcomes were overall survival and incidence of second cancer. RESULTS: A total of 24 348 patients with primary GBM were identified during the period from 2004 to 2013: 349 pediatric, 9841 adults and 14 518 elderly. There were significant differences in terms of sex, race, registry site, tumor histological type, tumor size and extension among the groups. The median survival time for pediatric, adult and elderly patients was 15, 15 and 5 months, respectively. Of the study population, 1.8% developed a second malignancy and the rates of the three groups were statistically different. Secondary tumors of the cranial nerves and other nervous system were the most common occurrence in the adults and elderly. Female, registry site, giant cell glioblastoma, undergoing surgery or radiation therapy were associated with developing a second malignancy. CONCLUSIONS: The risk of a second malignancy in GBM patients is 1.8%, and associated with certain patient and treatment factors.

Diagnosis and microsurgical treatment of spinal hemangioblastoma.

Spinal cord hemangioblastomas are rare benign tumors, with difficult surgical management and poor prognosis due to high vascularization. We aim to evaluate the diagnostic methods and microsurgical treatment of spinal cord hemangioblastoma. This retrospective study assessed 25 patients treated for spinal hemangioblastoma using microsurgery at Beijing Tiantan Hospital and Department of Neurosurgery, The General Hospital of Chinese People's Armed Police Forces, between October 2008 and October 2013. Clinical, imaging, and treatment data were collected. Meanwhile, efficacy was assessed with the McCormick grading system for spinal cord function. The symptoms lasted 17.0 ± 15.1 months. Sixteen (64 %) patients were suffering from von Hippel-Lindau disease; magnetic resonance imaging revealed the lesions in all patients. Intraoperative fluorescence angiography was helpful in identifying the feeding arteries and draining veins. Total tumor removal was achieved in all subjects. Patients were followed up for 21.3 ± 8.5 months. One week after surgery, neurological symptoms were improved in 22 patients, remained stable in 2 patients, and were aggravated in 1. The latter patient began to recover 7-10 days after surgery and was completely recovered within a month. At the last follow-up, all patients were alive, and all showed a McCormick grade ≤II. Microsurgery seems effective in the treatment of spinal cord hemangioblastoma. Intraoperative fluorescence angiography is helpful in defining the resection scope, to reduce intraoperative bleeding and prevent spinal swelling, which results in improved success rate.

Microsurgical Treatment of Meningiomas in the Torcular Herophili Region.

The Torcular Herophili region of the brain is anatomically complex, and surgery in this area requires much skill and care. Retrospective analysis on 35 cases of meningiomas in the Torcular Herophili region treated by microsurgery and confirmed by pathology. Tumor resection range was evaluated using the Simpson grading criteria. Postoperative complications and tumor recurrence were evaluated. Patients were followed up. The Karnofsky performance status was used to evaluate neurologic functions. Magnetic resonance venography (MRV) and magnetic resonance imaging (MRI) revealed the extent of disease in all patients. Simpson level I excision was done in 27 patients, level II in 5 patients, and level IV in 3 patients. Gamma knife treatment after surgery was performed in 3 patients. Symptoms of increased intracranial pressure were relieved after surgery. No patient died, and no patient suffered from any relevant operative complications and disabilities. Pathology reported typical meningioma (World Health Organization [WHO] level I) in 32 patients, and atypical meningioma (WHO level II) in 3 patients. Thirty-two patients were followed up for 0.5 to 5 years: 1 patient relapsed 2 years after operation (Simpson level IV excision), and 2 patients relapsed 3 years after operation (one Simpson level I and one level II). These results indicated that MRV should be performed to confirm the exact relationship between the tumor and venous sinus. The operative approach should be planned according to the MRI results, and the venous sinus should be preserved. Gamma knife might be a beneficial auxiliary treatment of meningioma in the Torcular Herophili region.

Bio-remediation of acephate-Pb(II) compound contaminants by Bacillus subtilis FZUL-33.

Removal of Pb(2+) and biodegradation of organophosphorus have been both widely investigated respectively. However, bio-remediation of both Pb(2+) and organophosphorus still remains largely unexplored. Bacillus subtilis FZUL-33, which was isolated from the sediment of a lake, possesses the capability for both biomineralization of Pb(2+) and biodegradation of acephate. In the present study, both Pb(2+) and acephate were simultaneously removed via biodegradation and biomineralization in aqueous solutions. Batch experiments were conducted to study the influence of pH, interaction time and Pb(2+) concentration on the process of removal of Pb(2+). At the temperature of 25°C, the maximum removal of Pb(2+) by B.subtilis FZUL-33 was 381.31±11.46mg/g under the conditions of pH5.5, initial Pb(2+) concentration of 1300mg/L, and contact time of 10min. Batch experiments were conducted to study the influence of acephate on removal of Pb(2+) and the influence of Pb(2+) on biodegradation of acephate by B.subtilis FZUL-33. In the mixed system of acephate-Pb(2+), the results show that biodegradation of acephate by B.subtilis FZUL-33 released PO4(3+), which promotes mineralization of Pb(2+). The process of biodegradation of acephate was affected slightly when the concentration of Pb(2+) was below 100mg/L. Based on the results, it can be inferred that the B.subtilis FZUL-33 plays a significant role in bio-remediation of organophosphorus-heavy metal compound contamination.

Nitric oxide signal is required for glutathione-induced enhancement of photosynthesis in salt-stressed Solanum lycopersicum L.

Reduced glutathione (γ-glutamyl-cysteinyl-glycine, GSH), the primary non-protein sulfhydryl group in organisms, plays a pivotal role in the plant salt stress response. This study aimed to explore the impact of GSH on the photosynthetic apparatus, and carbon assimilation in tomato plants under salt stress, and then investigate the role of nitric oxide (NO) in this process. The investigation involved foliar application of 5 mM GSH, 0.1% (w/v) hemoglobin (Hb, a nitric oxide scavenger), and GSH+Hb on the endogenous NO levels, rapid chlorophyll fluorescence, enzyme activities, and gene expression related to the Calvin cycle in tomato seedlings (Solanum lycopersicum L. cv. 'Zhongshu No. 4') subjected short-term salt stress (100 mM NaCl) for 24, 48 and 72 hours. GSH treatment notably boosted nitrate reductase (NR) and NO synthase (NOS) activities, elevating endogenous NO signaling in salt-stressed tomato seedling leaves. It also mitigated chlorophyll fluorescence (OJIP) curve distortion and damage to the oxygen-evolving complex (OEC) induced by salt stress. Furthermore, GSH improved photosystem II (PSII) electron transfer efficiency, reduced QA - accumulation, and countered salt stress effects on photosystem I (PSI) redox properties, enhancing the light energy absorption index (PIabs). Additionally, GSH enhanced key enzyme activities in the Calvin cycle and upregulated their genes. Exogenous GSH optimized PSII energy utilization via endogenous NO, safeguarded the photosynthetic reaction center, improved photochemical and energy efficiency, and boosted carbon assimilation, ultimately enhancing net photosynthetic efficiency (Pn) in salt-stressed tomato seedling leaves. Conversely, Hb hindered Pn reduction and NO signaling under salt stress and weakened the positive effects of GSH on NO levels, photosynthetic apparatus, and carbon assimilation in tomato plants. Thus, the positive regulation of photosynthesis in tomato seedlings under salt stress by GSH requires the involvement of NO.

Ascorbic Acid Improves Tomato Salt Tolerance by Regulating Ion Homeostasis and Proline Synthesis.

In this study, processing tomato (Solanum lycopersicum L.) 'Ligeer 87-5' was hydroponically cultivated under 100 mM NaCl to simulate salt stress. To investigate the impacts on ion homeostasis, osmotic regulation, and redox status in tomato seedlings, different endogenous levels of ascorbic acid (AsA) were established through the foliar application of 0.5 mM AsA (NA treatment), 0.25 mM lycorine (LYC, an inhibitor of AsA synthesis; NL treatment), and a combination of LYC and AsA (NLA treatment). The results demonstrated that exogenous AsA significantly increased the activities and gene expressions of key enzymes (L-galactono-1,4-lactone dehydrogenase (GalLDH) and L-galactose dehydrogenase (GalDH)) involved in AsA synthesis in tomato seedling leaves under NaCl stress and NL treatment, thereby increasing cellular AsA content to maintain its redox status in a reduced state. Additionally, exogenous AsA regulated multiple ion transporters via the SOS pathway and increased the selective absorption of K+, Ca2+, and Mg2+ in the aerial parts, reconstructing ion homeostasis in cells, thereby alleviating ion imbalance caused by salt stress. Exogenous AsA also increased proline dehydrogenase (ProDH) activity and gene expression, while inhibiting the activity and transcription levels of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and ornithine-δ-aminotransferase (OAT), thereby reducing excessive proline content in the leaves and alleviating osmotic stress. LYC exacerbated ion imbalance and osmotic stress caused by salt stress, which could be significantly reversed by AsA application. Therefore, exogenous AsA application increased endogenous AsA levels, reestablished ion homeostasis, maintained osmotic balance, effectively alleviated the inhibitory effect of salt stress on tomato seedling growth, and enhanced their salt tolerance.

Impact of sex and serum lipids interaction on working memory: A large-scale brain networks study.

BACKGROUNDS: Previous studies have demonstrated that both serum lipid levels and sex are crucial factors associated with individual cognition. However, the impact of sex and serum lipid interaction effects on the brain and cognition remains largely unknown. This study aimed to explore the underlying neural mechanisms among sex, serum lipids, and cognition using large-scale brain networks. METHODS: Resting-state functional MRI data were collected from 157 young healthy adults. Independent component analysis was used to examine large-scale inter- and intra-network functional connectivity (FCs). Peripheral venous blood samples were collected to measure serum lipid levels. The three-back task was employed to assess cognition (i.e., working memory). General linear model, correlation, and mediation analyses were conducted to examine the interaction effects of sex and serum lipids on large-scale brain networks and their relationship with working memory. RESULTS: We found that inter-network connectivity with the executive control network at its core was more susceptible to sex and triglyceride interaction effects. The intra-network connectivity in the dorsal attention networks (DANs), lateral visual networks, and anterior default mode networks was influenced by the interaction effects of sex and total cholesterol (TC)/low-density lipoprotein cholesterol. Specifically, correlations between serum lipids and affected brain networks were found to be sex-specific. In addition, higher intra-network FC in the right inferior parietal (R-IPL) of the DAN correlated with a longer three-back reaction time in females. More importantly, the relationship between serum TC levels and three-back reaction time was mediated by intra-network connectivity in the R-IPL of the DAN. CONCLUSIONS: Our findings describe the impact of sex and serum lipid interaction effects on large-scale brain networks, as well as on cognitive function. Our data suggest that sex-specific usage of serum lipids or brain networks would be beneficial for monitoring and therapy in dyslipidemia-related cognition decline.

The Protective Effect of Exogenous Ascorbic Acid on Photosystem Inhibition of Tomato Seedlings Induced by Salt Stress.

This study investigated the protective effects of exogenous ascorbic acid (AsA, 0.5 mmol·L-1) treatment on salt-induced photosystem inhibition in tomato seedlings under salt stress (NaCl, 100 mmol·L-1) conditions with and without the AsA inhibitor lycorine. Salt stress reduced the activities of photosystem II (PSII) and PSI. AsA treatment mitigated inhibition of the maximal photochemical efficiency of PSII (Fv/Fm), maximal P700 changes (Pm), the effective quantum yields of PSII and I [Y(II) and Y(I)], and non-photochemical quenching coefficient (NPQ) values under salt stress conditions both with and without lycorine. Moreover, AsA restored the balance of excitation energy between two photosystems (ß/α-1) after disruption by salt stress, with or without lycorine. Treatment of the leaves of salt-stressed plants with AsA with or without lycorine increased the proportion of electron flux for photosynthetic carbon reduction [Je(PCR)] while decreasing the O2-dependent alternative electron flux [Ja(O2-dependent)]. AsA with or without lycorine further resulted in increases in the quantum yield of cyclic electron flow (CEF) around PSI [Y(CEF)] while increasing the expression of antioxidant and AsA-GSH cycle-related genes and elevating the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG). Similarly, AsA treatment significantly decreased the levels of reactive oxygen species [superoxide anion (O2-) and hydrogen peroxide (H2O2)] in these plants. Together, these data indicate that AsA can alleviate salt-stress-induced inhibition of PSII and PSI in tomato seedlings by restoring the excitation energy balance between the photosystems, regulating the dissipation of excess light energy by CEF and NPQ, increasing photosynthetic electron flux, and enhancing the scavenging of reactive oxygen species, thereby enabling plants to better tolerate salt stress.

Prediction of cadmium contents in rice grains from Quaternary sediment-distributed farmland using field investigations and machine learning.

The Quaternary sediment-distributed regions of South China are suitable for rice cultivation, which is crucial for ensuring food security. Spatial correlations between soil cadmium (Cd) and rice Cd contents are generally poor, making the evaluation of rice quality and associated health risks challenging. In this study, we developed machine learning algorithms for predicting rice Cd contents using 654 data pairs of soil-rice samples collected in Guangxi province, China. After a comprehensive comparison, our results showed that the random forest (RF) had the better performance than artificial neural network (ANN) based on all the data (RMSEtesting 0.066 vs. 0.099 and R2testing 0.860 vs. 0.688). The feature importance analysis showed that soil CaO, Cd, elevation, and rainfall were the four most important features affecting the rice Cd contents in the study area. Using the established RF-predicated model, the rice Cd contents were predicted at the provincial level with an additional dataset of 1176 paddy soil samples. The prediction result revealed about 23 % of farmland cultivated rice with Cd content over 0.2 mg kg-1 in the study area. Therefore, it is recommended to implement strict measures by local agricultural departments to reduce rice Cd contents and ensure food safety in these areas. Our study provides valuable insights into the prediction of rice Cd contents, thus contributing to ensuring food safety and preventing Cd exposure-associated health risks.

Soil selenium enrichment in the Loess Plateau of China: Geogenic evidence, spatial distribution, and it's influence factors.

The selenium (Se)-deficient soil belt in China has gained widespread attention. During large-scale soil surveys in China, Se-rich soils within low-Se belts have been identified. However, the sources of Se in those soils and the controlling factors for their enrichment remain unclear. Here we summarize Se concentrations and spatial distributions in the Yuanzhou district of the Loess Plateau. We evaluated Se variations in soil profiles, Se migration into water bodies, and considered soil indicators, topographic characteristics and the influence of land-use types on soil Se concentrations. The average Se concentration in the topsoil of the Yuanzhou district was 0.164 µg/g. High-Se soils (>0.222 µg/g) were found in the western valley plain and the southern red bed hilly area, as well as sporadically in higher elevation forestland and grassland areas in the east. Enrichment of Se in the topsoil in the eastern and southern areas was primarily due to Se adsorption and accumulation by soil organic matter as well as enrichment in gypsum, berlinite, and clay minerals during soil formation. Widespread enrichment in the southern area was linked to high Se concentrations in red Tertiary sedimentary rocks. In the western area, enrichment of Se in topsoil was found on both sides of the Qingshui River at low elevations with gentle slopes, with river water being the primary carrier of Se enrichment. These findings provide valuable insights into the epigenetic geochemical behavior of soil Se in China's low-Se belt that accounts for development of Se-rich soils in the region.

Spatially varying relationships of soil Se concentration and rice Se concentration in Guangxi, China: A geographically weighted regression approach.

In recent years, the biogeochemical behavior and environmental impact of Selenium (Se) on soil-plant systems have received widespread attention, and traditional statistical methods reveal generally positive correlations between rice Se and soil Se. However, that initial positive relationship may have been obscured by local external factors. Using local scale data from the geochemical evaluation of land quality project, this work employed geographically weighted regression (GWR) to examine the spatial variation of rice Se (as the dependent variable) and soil Se (as the independent variable) in Guangxi. Strong and weak correlation coefficients occur between rice Se and soil Se, thereby indicating that their relationships are spatially varying. Guangxi is characterized by significantly positive correlations in most areas, with weak correlations mostly found in the south-western and central-eastern regions. Areas with weak correlation can be divided into two patterns: high soil Se with low rice Se and high rice Se with low soil Se. The unique patterns are correlated with distinct natural factors, particularly the abundance of Fe-rich soils in the carbonate area; by contrast, sandstone areas in central Guangxi may have been affected by anthropogenic activities. To reveal the spatially varying relationships at the local scale, we employed GWR, an effective tool that allowed us to identify the association between environmental variables and influencing factors and explore spatially varying relationships between them. This study breaks through the existing understanding that soil Se is completely positively correlated with rice Se for the first time, and concludes that their correlation is spatially variable, providing an effective approach for the study of complex relationships.