Spatial and temporal distribution characteristics and risk assessment of heavy metals in groundwater of Pingshuo mining area.

Groundwater pollution in the Pingshuo mining area is strongly associated with mining activities, with heavy metals (HMs) representing predominant pollutants. To obtain accurate information about the pollution status and health risks of groundwater, 189 groups of samples were collected from four types of groundwater, during three periods of the year, and analyzed for HMs. The results showed that the concentration of HMs in groundwater was higher near the open pit, waste slag pile, riverfront area, and human settlements. Except for Ordovician groundwater, excessive HMs were found in all investigated groundwater of the mining area, as compared with the standard thresholds. Fe exceeded the threshold in 13-75% of the groundwater samples. Three sources of HMs were identified and quantified by Pearson's correlation analysis and the PMF model, including coal mining activities (68.22%), industrial, agricultural, and residential chemicals residue and leakage (16.91%), and natural sources (14.87%). The Nemerow pollution index revealed that 7.58% and 100% of Quaternary groundwater and mine water samples were polluted. The health risk index for HMs in groundwater showed that the non-carcinogenic health risk ranged from 0.18 to 0.42 for adults, indicating an acceptable level. Additionally, high carcinogenic risks were identified in Quaternary groundwater (95.45%), coal series groundwater (91.67%), and Ordovician groundwater (26.67%). Both carcinogenic and non-carcinogenic risks were greater for children than adults, highlighting their increased vulnerability to HMs in groundwater. This study provides a scientific foundation for managing groundwater quality and ensuring drinking water safety in mining areas.

[Hydrochemical Characteristics and Control Factors of Groundwater in the Northwest Salt Lake Basin].

Taking the Tugeligaole sub-basin of the Jilantai Salt Lake Basin in Inner Mongolia as the typical study area, the groundwater samples of 22 points were collected, and their main characteristic indexes were tested during the wet season and the dry season separately in 2021. Mathematical statistics, Piper triangular diagrams, a Gibbs plot, ionic relations, and factor analysis were used to analyze and discuss the hydrochemical characteristics and formation mechanism of groundwater in different periods. Based on the evaluation of the groundwater quality using the water quality index(WQI) method, the potential risks of groundwater Cr6+ and F- were evaluated using the health risk evaluation model. The results showed that the groundwater was overall weakly alkaline; the dominant anions and cations during the different periods were Cl- and Na+, and the water chemistry type was mainly Cl--Na+; the groundwater quality was generally good, and the difference in water quality between the wet season and the dry season was not significant; adults and children had higher carcinogenic health risks in the dry season than that in the wet season, and the health risks of children were significantly higher than those in adults. The maximum carcinogenic health risk of drinking water exposure to Cr6+ in adults and children was higher than the maximum acceptable risk level(5×10-5). The chemical evolution of groundwater was mainly affected by evaporative concentration, evaporative salt rock dissolution, and cation exchange, and the main control factors were evaporative concentration(contribution rate of 54.19%), native geological environment factors(contribution rate of 12.99%), and carbonate rock dissolution(contribution rate of 11.66%). The study results have significance to some degree to the sustainable exploitation and utilization of groundwater resources and environmental protection of the salt lake basin.

[Risk Assessment of Heavy Metals in Dust Fall Around Reservoirs in Typical Ecologically Fragile Areas and Traceability Based on APCS-MLR Model].

To assess the health risk status and pollution sources of heavy metals in the atmosphere of ecologically vulnerable areas, the surrounding area of Dahekou Reservoir in Xilingol League was selected as the study area. From 2021 to 2022, 12 monitoring points for atmospheric dust fall were collected for a period of one year. A total of 144 samples were collected to determine the contents of eight types of heavy metals, namely Cr, Ni, Pb, Cu, Zn, Mn, As, and Cd. The potential ecological index (Eri) and health risk assessment model were used to assess the risk level of atmospheric heavy metals on ecological security and human health. The analysis of enrichment factors, principal components, and the model of absolute principal component multiple linear regression (APCS-MLR) receptor were used to analyze the sources of heavy metal pollution qualitatively in the atmosphere of the study area. The results showed that:① the mean value of the comprehensive potential ecological risk of heavy metals in the annual atmospheric dust fall in the study area was at a high ecological risk, and only the Cd value was at a very high risk level among the heavy metals, whereas the remaining were at a slight risk. ② The results of the health risk showed that intake by hand, mouth, and skin contact were the main exposure routes, which led to non-carcinogenic and carcinogenic risks. Children were under non-carcinogenic and acceptable carcinogenic risks in different months. During those months, the main source of the risks was As. ③ Through enrichment factor analysis, principal component analysis, and APCS-MLR receptor model calculation, the results revealed that the proportion of wind-blown sources was the largest, accounting for 37.82%, and the contribution rates of coal combustion and traffic sources to Cu, Cd, Pb, and Zn were 73.01%, 40.22%, 70.31%, and 32.82%, respectively. The contribution rate of mining activities to As was 42.59%, while that of industrial sources of Cd was 22.01%; the contributions of other human activity sources of Cd, As, Pb, and Zn were 21.12%, 34.40%, 23.04%, and 32.15%, respectively.

Hydrochemical assessments and driving forces of groundwater quality and potential health risks of sulfate in a coalfield, northern Ordos Basin, China.

Groundwater is the primary water source in coalfields under arid and semiarid climates. However, the problem of excessive concentrations of sulfate, which is a constant component in coalfields, and its potential health risks are often neglected in Northwest, China. To determine the groundwater quality, health threats, and driving forces of sulfate in coal mine groundwater, this study performed hydrochemical and isotopic analyses of 61 groundwater samples from a typical coalfield in northwestern China. We found that phreatic groundwater had lower total dissolved solid (TDS) and freshwater hydrochemical types (mainly Ca-HCO3 and Ca-Na + K-HCO3 types). In contrast, confined groundwater showed saline affinity (Na + K-SO4 type) and high TDS values, and the quality was unacceptable for drinking, with EWQI values larger than 100, which could be attributed to its high SO42- concentration. In addition, confined groundwater was also unsuitable for irrigation with high values of electric conductivity (EC), sodium absorption ratio (SAR), and Na%. Combining with isotopic analysis (δD, δ18Owater, δ34S and δ18Osulfate), the sulfate of confined and phreatic groundwater was controlled by gypsum dissolution and irrigation activities. As for public human health, SO42- poses potential non-carcinogenic risks to various populations, especially children. Therefore, the impact of geogenic and anthropogenic factors should be paid attention to, including the reduction of the use of sulfur-containing fertilizers and discharge of sulfur-containing sewage; and the water treatment should be carried out. Importantly, there is a need to adopt a strategy of water supply from multiple sources to ensure human health.

The histone demethylase Jmjd3 regulates zebrafish myeloid development by promoting spi1 expression.

The histone demethylase Jmjd3 plays a critical role in cell lineage specification and differentiation at various stages of development. However, its function during normal myeloid development remains poorly understood. Here, we carried out a systematic in vivo screen of epigenetic factors for their function in hematopoiesis and identified Jmjd3 as a new epigenetic factor that regulates myelopoiesis in zebrafish. We demonstrated that jmjd3 was essential for zebrafish primitive and definitive myelopoiesis, knockdown of jmjd3 suppressed the myeloid commitment and enhanced the erythroid commitment. Only overexpression of spi1 but not the other myeloid regulators rescued the myeloid development in jmjd3 morphants. Furthermore, preliminary mechanistic studies demonstrated that Jmjd3 could directly bind to the spi1 regulatory region to alleviate the repressive H3K27me3 modification and activate spi1 expression. Thus, our studies highlight that Jmjd3 is indispensable for early zebrafish myeloid development by promoting spi1 expression.

Vibsanin B preferentially targets HSP90ß, inhibits interstitial leukocyte migration, and ameliorates experimental autoimmune encephalomyelitis.

Interstitial leukocyte migration plays a critical role in inflammation and offers a therapeutic target for treating inflammation-associated diseases such as multiple sclerosis. Identifying small molecules to inhibit undesired leukocyte migration provides promise for the treatment of these disorders. In this study, we identified vibsanin B, a novel macrocyclic diterpenoid isolated from Viburnum odoratissimum Ker-Gawl, that inhibited zebrafish interstitial leukocyte migration using a transgenic zebrafish line (TG:zlyz-enhanced GFP). We found that vibsanin B preferentially binds to heat shock protein (HSP)90ß. At the molecular level, inactivation of HSP90 can mimic vibsanin B's effect of inhibiting interstitial leukocyte migration. Furthermore, we demonstrated that vibsanin B ameliorates experimental autoimmune encephalomyelitis in mice with pathological manifestation of decreased leukocyte infiltration into their CNS. In summary, vibsanin B is a novel lead compound that preferentially targets HSP90ß and inhibits interstitial leukocyte migration, offering a promising drug lead for treating inflammation-associated diseases.

miR-142-3p acts as an essential modulator of neutrophil development in zebrafish.

Neutrophils play critical roles in vertebrate innate immune responses. As an emerging regulator in normal myelopoiesis, the precise roles of microRNA in the development of neutrophils have yet to be clarified. Using zinc-finger nucleases, we have successfully generated heritable mutations in miR-142a and miR-142b and showed that hematopoietic-specific miR-142-3p is completely deleted in miR-142 double mutant zebrafish. The lack of miR-142-3p resulted in aberrant reduction and hypermaturation of neutrophils in definitive myelopoiesis, as well as impaired inflammatory migration of neutrophils in the fetal stage. Furthermore, the adult myelopoiesis in the miR-142-3p-deficient zebrafish was also affected, producing irregular hypermature neutrophils with increased cell size and a decreased nucleocytoplasmic ratio. Additionally, miR-142-3p-deficient zebrafish are expected to develop a chronic failure of myelopoiesis with age. Transcriptome analysis showed an aberrant activation of the interferon γ (IFN-γ) signaling pathway in myelomonocytes after miR-142-3p deletion. We found that the reduced number and hypermaturation of neutrophils caused by loss of miR-142-3p was mainly mediated by the abnormally activated IFN-γ signaling, especially the upregulation of stat1a and irf1b. Taken together, we uncovered a novel role of miR-142-3p in maintaining normal neutrophil development and maturation.

Functional and molecular features of the calmodulin-interacting protein IQCG required for haematopoiesis in zebrafish.

We previously reported a fusion protein NUP98-IQCG in an acute leukaemia, which functions as an aberrant regulator of transcriptional expression, yet the structure and function of IQCG have not been characterized. Here we use zebrafish to investigate the role of iqcg in haematopoietic development, and find that the numbers of haematopoietic stem cells and multilineage-differentiated cells are reduced in iqcg-deficient embryos. Mechanistically, IQCG binds to calmodulin (CaM) and acts as a molecule upstream of CaM-dependent kinase IV (CaMKIV). Crystal structures of complexes between CaM and IQ domain of IQCG reveal dual CaM-binding footprints in this motif, and provide a structural basis for a higher CaM-IQCG affinity when deprived of calcium. The results collectively allow us to understand IQCG-mediated calcium signalling in haematopoiesis, and propose a model in which IQCG stores CaM at low cytoplasmic calcium concentrations, and releases CaM to activate CaMKIV when calcium level rises.

Pten regulates homeostasis and inflammation-induced migration of myelocytes in zebrafish.

BACKGROUND: Loss of the tumor suppressor phosphatase and tensin homolog (PTEN) is frequently observed in hematopoietic malignancies. Although PTEN has been implicated in maintaining the quiescence of hematopoietic stem cells (HSCs), its role in hematopoiesis during ontogeny remains largely unexplored. METHODS: The expression of hematopoietic marker genes was analyzed via whole mount in situ hybridization assay in ptena and ptenb double mutant zebrafish. The embryonic myelopoiesis was characterized by living imaging and whole mount in situ immunofluorescence with confocal microscopy, as well as cell-specific chemical staining for neutrophils and macrophages. Analyses of the involved signaling pathway were carried out by inhibitor treatment and mRNA injection. RESULTS: Pten-deficient zebrafish embryos exhibited a strikingly increased number of myeloid cells, which were further characterized as being immune deficient. In accordance with this finding, the inhibition of phosphoinositide 3-kinase (PI3K) or the mechanistic target of rapamycin (mTOR) corrected the expansive myelopoiesis in the pten-deficient embryos. Further mechanistic studies revealed that the expression of cebpa, a critical transcription factor in myeloid precursor cells, was downregulated in the pten-deficient myeloid cells, whereas the injection of cebpa mRNA markedly ameliorated the dysmyelopoiesis induced by the loss of pten. CONCLUSIONS: Our data provide in vivo evidence that definitive myelopoiesis in zebrafish is critically regulated by pten via the elevation of cebpa expression.

miR-34b regulates multiciliogenesis during organ formation in zebrafish.

Multiciliated cells (MCCs) possess multiple motile cilia and are distributed throughout the vertebrate body, performing important physiological functions by regulating fluid movement in the intercellular space. Neither their function during organ development nor the molecular mechanisms underlying multiciliogenesis are well understood. Although dysregulation of members of the miR-34 family plays a key role in the progression of various cancers, the physiological function of miR-34b, especially in regulating organ formation, is largely unknown. Here, we demonstrate that miR-34b expression is enriched in kidney MCCs and the olfactory placode in zebrafish. Inhibiting miR-34b function using morpholino antisense oligonucleotides disrupted kidney proximal tubule convolution and the proper distribution of distal transporting cells and MCCs. Microarray analysis of gene expression, cilia immunostaining and a fluid flow assay revealed that miR-34b is functionally required for the multiciliogenesis of MCCs in the kidney and olfactory placode. We hypothesize that miR-34b regulates kidney morphogenesis by controlling the movement and distribution of kidney MCCs and fluid flow. We found that cmyb was genetically downstream of miR-34b and acted as a key regulator of multiciliogenesis. Elevated expression of cmyb blocked membrane docking of centrioles, whereas loss of cmyb impaired centriole multiplication, both of which resulted in defects in the formation of ciliary bundles. Thus, miR-34b serves as a guardian to maintain the proper level of cmyb expression. In summary, our studies have uncovered an essential role for miR-34b-Cmyb signaling during multiciliogenesis and kidney morphogenesis.

Activated N-Ras signaling regulates arterial-venous specification in zebrafish.

BACKGROUND: The aberrant activation of Ras signaling is associated with human diseases including hematological malignancies and vascular disorders. So far the pathological roles of activated Ras signaling in hematopoiesis and vasculogenesis are largely unknown. METHODS: A conditional Cre/loxP transgenic strategy was used to mediate the specific expression of a constitutively active form of human N-Ras in zebrafish endothelial and hematopoietic cells driven by the zebrafish lmo2 promoter. The expression of hematopoietic and endothelial marker genes was analyzed both via whole mount in situ hybridization (WISH) assay and real-time quantitative PCR (qPCR). The embryonic vascular morphogenesis was characterized both by living imaging and immunofluorescence on the sections with a confocal microscopy, and the number of endothelial cells in the embryos was quantified by flow cytometry. The functional analyses of the blood circulation were carried out by fluorescence microangiography assay and morpholino injection. RESULTS: In the activated N-Ras transgenic embryos, the primitive hematopoiesis appeared normal, however, the definitive hematopoiesis of these embryos was completely absent. Further analysis of endothelial cell markers confirmed that transcription of arterial marker ephrinB2 was significantly decreased and expression of venous marker flt4 excessively increased, indicating the activated N-Ras signaling promotes the venous development at the expense of arteriogenesis during zebrafish embryogenesis. The activated N-Ras-expressing embryos showed atrophic axial arteries and expansive axial veins, leading to no definitive hematopoietic stem cell formation, the blood circulation failure and subsequently embryonic lethality. CONCLUSIONS: Our studies revealed for the first time that activated N-Ras signaling during the endothelial differentiation in vertebrates can disrupt the balance of arterial-venous specification, thus providing new insights into the pathogenesis of the congenital human vascular disease and tumorigenic angiogenesis.

Phospholipase C gamma-1 is required for granulocyte maturation in zebrafish.

The regulation of hematopoiesis is generally evolutionarily conserved from zebrafish to mammals, including hematopoietic stem cell formation and blood cell lineage differentiation. In zebrafish, primitive granulocytes originate at two distinct regions, the anterior lateral plate mesoderm (A-LPM) and the intermediate cell mass (ICM). Few studies in the zebrafish have examined genes specifically required for the granulocytic lineage. In this study, we identified the responsible gene for a zebrafish mutant that has relatively normal hematopoiesis, except decreased expression of the granulocyte-specific gene mpx. Positional cloning revealed that phospholipase C gamma-1 (plcg1) was mutated. Deficiency of plcg1 function specifically affected development of granulocytes, especially the maturation process. These results suggested that plcg1 functioned specifically in zebrafish ICM granulopoiesis for the first time. Our studies suggest that specific pathways regulate the differentiation of the hematopoietic lineages.

Thrombin receptor regulates hematopoiesis and endothelial-to-hematopoietic transition.

Hematopoietic development and vascular development are closely related physiological processes during vertebrate embryogenesis. Recently, endothelial-to-hematopoietic transition (EHT) was demonstrated to be critical for hematopoietic stem and progenitor cell induction, but its underlying regulatory mechanisms remain poorly understood. Here we show that thrombin receptor (F2r), a protease-activated G protein-coupled receptor required for vascular development, functions as a negative regulator during hematopoietic development. F2r is significantly upregulated during hematopoietic differentiation of mouse embryonic stem cells (mESCs) and zebrafish hematopoietic development. Pharmacological or genetic inhibition of F2r promotes hematopoietic differentiation, whereas F2r overexpression shows opposite effects. Further mechanistic studies reveal that F2r-RhoA/ROCK pathway inhibits EHT in vitro and negatively regulates zebrafish EHT and hematopoietic stem cell induction in vivo. Taken together, this study demonstrates a fundamental role of F2r-RhoA/ROCK pathway in vertebrate hematopoiesis and EHT, as well as an important molecular mechanism coordinating hematopoietic and vascular development.

Spatio-temporal expression of chromogranin A during zebrafish embryogenesis.

Chromogranin A (CHGA), a protein participating in the biogenesis of dense core secretory granules in various neuroendocrine tissues, plays a critical role in the release of hormones/peptides and the pathogenesis of pheochromocytoma. However, little is known about the developmental origin of CHGA-expressing cells during embryogenesis. Here, we report the structural characterization and spatio-temporal expression pattern of zebrafish (Danio rerio) ortholog of mammalian CHGA. The earliest expression of chga transcripts was observed at 16 h post fertilization in the developing cranial ganglia as six distinct cellular masses arranged bilaterally as strings of beads in the dorsal root ganglia (DRG) precursors along the dorsal trunk. With development advancing, the chga transcripts were expressed abundantly in diencephalon, mesencephalon, and rhombencephalon as well as in the DRG. Interestingly, double in situ hybridization assay of chga with genes expressed in pronephros (Wilms' tumor suppressor 1, wt1), adrenal cortex (side-chain cleavage enzyme, scc), and sympathoadrenal neuron/chromaffin cell (dopamine-beta-hydroxylase, dbh), respectively, showed that the chga-expressing cells are spatially separated from wt1-, scc-, and dbh-positive cell populations during early embryonic development. The pronephros region does not express chga even up to 7 days post fertilization, while chga positive-staining cells bind in the brain and DRG, indicating that chga may play an important role in nervous system development during the early embryonic stages.

The pu.1 promoter drives myeloid gene expression in zebrafish.

PU.1 is a member of the Ets family of transcription factors and plays an essential role in the development of both myeloid and lymphoid cells. To examine zebrafish pu.1 (zpu.1) expression in subpopulations of blood cells during zebrafish development, we linked a 9-kb zebrafish genomic fragment upstream of the zpu.1 initiator codon to green fluorescent protein (GFP) and microinjected this construct to generate stable transgenic lines. GFP-positive fluorescent myeloid precursors were observed migrating from the anterolateral mesoderm in living embryos from 16 to 28 hours after fertilization (hpf) in a pattern that overlaps the expression pattern of endogenous zpu.1 mRNA. Analysis of larval histologic sections revealed GFP-expressing hematopoietic cells in the developing zebrafish kidney. Flow cytometric analysis of cells from adult whole kidney marrow revealed 2 discrete subpopulations of GFP-positive cells, which after cell sorting exhibited either myeloid or early lymphoid morphology. Thus, the zebrafish zpu.1 promoter fragment used here is capable of driving reporter gene expression in subsets of embryonic and adult hematopoietic cells. These transgenic lines will be useful to dissect the cellular and molecular control of myeloid cell differentiation, and this promoter fragment may prove useful in the development of zebrafish models of acute myeloid leukemia.