[Advances in On-site Analytical Methods for Inorganic Arsenic in Environmental Water].

Arsenic is a ubiquitous metalloid element in the environment. Arsenic is classified as a group A carcinogen and has caused serious impacts on human health. For example, chronic poisoning caused by arsenic in groundwater is a global health problem. The forms of arsenic in environmental water are diverse, which can easily be transformed into each other during the sampling process and transportation, resulting in errors in laboratory analysis results. Therefore, developing on-site analytical methods for arsenic and acquiring accurate data are the basis for the study of the morphological transformation and bio-absorption process of arsenic and accurately evaluating its toxicity. In the past few decades, laboratory-based analytical methods for arsenic have developed rapidly, but there are still huge challenges in the on-site analysis of arsenic. This review summarized the relevant reviews on analytical methods of arsenic in environmental water in the past decade (2011-2022); discussed the advances in on-site analytical methods such as colorimetric methods, luminescence-based methods, and electrochemical methods of arsenic; anticipated the future development of on-site analytical methods for arsenic in environmental waters; and provided references for the development and applications of new methods.

[Spatial and Temporal Distribution of Aerobic Denitrification Bacterial Community in Sediments of Gangnan Reservoir].

In order to study the spatial and temporal distribution characteristics of aerobic denitrification bacteria in the sediments of Gangnan Reservoir, the aerobic denitrification bacterial community was analyzed using a MiSeq high-throughput sequencing technique based on the napA gene. Moreover, the composition, diversity, difference, and network analysis of the aerobic denitrification bacterial community were investigated. The results showed higher α-diversity (Chao1 index, Observed species index, and Shannon index) in autumn and winter than that in spring and summer; that is, the richness and diversity of sampling sites in autumn and winter were higher. In terms of spatial distribution, the Chao1 index, Observed species index, Shannon index, and Simpson index of the bacterial community in the sampling sites in the transition zone were higher than those in the sampling sites in the inflow area and the main reservoir area, indicating that the richness and diversity of the bacterial community in the sampling sites in the transition zone were the highest. The aerobic denitrifying bacteria in the sediments of Gangnan Reservoir mainly belong to Protebacteria. The first dominant class was ß-Proteobacteria, and the first dominant genus was Thauera. A Venn diagram analysis indicated that the community of aerobic denitrification bacteria exhibited significant spatial and temporal differences. At the spatial level, there were higher numbers of different species based on LEfSe analysis than that at the seasonal level. Among the marker species screened by random forest analysis, Comamonas had the highest contribution in all spatial sampling sites, whereas Pectobacterium had the highest contribution in all seasonal sampling sites. Network analysis showed that there were nine modules, including 565 edges of 297 nodes; 47 keystone species were obtained based on the indicator OTUs analysis and network analysis. The principal co-ordinates analysis revealed that keystone species in the spatial distribution exhibited significant differences (Adonis, P<0.001). The results of this study provide scientific basis for the separation and identification of efficient aerobic denitrifying bacteria.

[Temporal and Spatial Distribution Characteristics and Driving Factors of Denitrification Bacterial Community Structure from Landscape Water in Hebei Province: Taking Shijiazhuang as Example].

Landscape water is an important part of urban water systems, and excessive nitrogen affects its ecological functions. This study aimed to investigate the temporal and spatial distribution characteristics and driving factors of the community structure of denitrifying bacteria from landscape water. The functional gene nirS was used as a functional marker to explore the community of denitrifying bacteria in the water and sediment of landscape water. Based on parameters of the water and sediment, the temporal and spatial distribution characteristics and driving factors of the community of denitrifying bacteria were studied. The results showed significant seasonal differences in water parameters and spatial differences in sediment nitrogen (P<0.001). No significant difference (P>0.05) was observed in α-diversity; the EC and SOEF-NH4+-N were important factors affecting the α-diversity of the water and sediment. Denitrifying bacteria mainly belonged to the phylum Proteobacteria and the genera Dechloromonas, Rhodocyclaceae, Pseudomonas, Rhodobacter, and Thauera. Principal coordinate analysis revealed that the community of denitrifying bacteria in the water and sediment exhibited significant spatial differences (P<0.001); keystone denitrifying bacteria in the water also exhibited significant spatial differences (P<0.001). RDA and RF analysis showed that the permanganate index and TP were the main environmental factors affecting the total and keystone denitrifying bacteria in the water; SOEF-NH4+-N, IEF-NH4+-N, and WAEF-NO3--N were the main environmental factors affecting the total and keystone denitrifying bacteria in the sediment. These findings could serve as a reference to understand the interaction mechanism between nitrogen and denitrification bacterial communities in landscape water.

[Spatial Distribution Characteristics of the Spectrum, Source Analysis, and Nitrogen Response of Dissolved Organic Matter in Summer Rainfall in the Hebei Province].

Dissolved organic matter(DOM) is an important component of the organic matter in the environment. This study explored the characteristics of DOM. The components and spectral characteristics of rainwater DOM were measured using Ultraviolet-visible absorption spectrum(UV-vis) and three-dimensional fluorescence spectrum in the Hebei province. The results showed significant differences for DOM molecular weight in the northern, central, and southern region; the DOM of the northern region exhibited the lowest molecular weight. Two humic-like(C1 and C4), one protein-like(C2) and one fulvic-like(C3) components were identified by parallel factor(PARAFAC) analysis. Component C2 had a significant positive correlation with components C3 and C4(P<0.001), which may have similar sources. The C2(protein-like substances) accounted for the major proportion of DOM with the average abundance 40.59%. The DOM components based on PARAFAC exhibited significantly difference between city and country regions without spatial difference, which was consistent with the result of fluorescence regional integration(FRI). The protein-like substances based on FRI were the main components, which accounted for 61.59%-89.01%. Redundancy analysis(RDA) showed that total nitrogen, nitrate, and ammonia were the main environmental factors determining the distribution of DOM. Spectral indices presented a significant difference between city and country regions. High fluorescence(FI) and biological(BIX) and low humification(HIX) values showed that summer rain exhibited the strong autochthonous and low humification characteristics, and country region have stronger autochthonous characteristics than city region. The regression analysis demonstrates that the prediction accuracy of rainwater quality parameters in city region is high. From all the results, rainwater DOM, showing strong autogenous characteristics, exhibited significant differences between city and country regions without spatial difference in Hebei. Meanwhile, it can also provide technical support for rainwater nitrogen concentration prediction based on DOM components.

[Structure of Aerobic Denitrification Bacterial Community in Response to Dissolved Organic Matter in Baiyangdian Lake During the Water Delivery Period].

Dissolved organic matter (DOM) plays an important role in the evolution of microbial communities. Meanwhile, ecological water delivery is an important feature of Baiyangdian Lake. To explore how the structure of the aerobic denitrification bacteria community responds to DOM during the water delivery period, the DOM components of water were examined and high-throughput sequencing of aerobic denitrification bacteria was performed. The results showed significant differences in DOM concentration in Baiyangdian Lake, with the estuary area exhibiting lower DOM concentrations. The water exhibited strong autogenous source, while DOM in the estuary area had a higher molecular weight and degree of humification. Three protein-like substances (C1, C2, and C4) and one humic-like substance (C3) were identified through PARAFAC. The protein-like substances accounted for the major proportion of DOM, which was consistent with the results of fluorescence regional integration (FRI). The genera of the water body were mainly in the Protebacterice phylum, including Cupriavidus, Aeromonas, Thauera, Shewanella, and Pseudomonas. Meanwhile, Cupriavidus, Thauera, Shewanella, Agrobacterium, and Pseudomonas were the main indicator species, according to random forest (RF) analysis. Through network analysis, 35 key nodes of the network were obtained, belonging to Thauera, Cupriavidus, and Unclassified_bacteria, respectively. Redundancy analysis (RDA) showed that a humic-like substance was the main environmental factor regulating the whole structure of the aerobic denitrification bacterial community, while protein-like substances played important roles in changes to the indicator species and key nodes of the community. Overall, protein-like substances could provide an important reference for selecting carbon sources during the screening of efficient and cold resistance aerobic denitrification bacteria that are adapted to actual water bodies.

[Analysis of Water Quality and Exchange Flux of Interstitial Water-Overlying Water in Sediments of Baiyangdian Entrance Area in Summer].

In order to reveal the interaction of overlying water-interstitial water nitrogen and phosphorus nutrient salt in summer at the entrance region of Baiyangdian Lake, this study sampled six main rivers in the region during July 2019. An analysis of the overlying water and interstitial water quality characteristics and the diffusion flux of applied nutrients at the sediment-water interface revealed the effects of nutrient diffusion on sediments and overlying water. The overlying water analysis showed that the water quality was slightly alkaline in the Baiyangdian Lake. The content of dissolved oxygen (DO) was lower, which provided an anaerobic environment for the release of endogenous pollutants from sediments. The ammonia nitrogen (NH4+-N) ranged from 0.35 to 1.76 mg·L-1, and the content of ammonia nitrogen was the highest in the Zhulong River, which was the main source of water supply. The nitrate nitrogen (NO3--N) content ranged from 0.75 to 1.97 mg·L-1. The total dissolved nitrogen (TDN) ranged from 0.99 to 2.70 mg·L-1, and the content of TDN was the highest in Puhe River. The content of total dissolved phosphorus (TDP) was 0.03 to 0.15 mg·L-1, and the content of TDP was the highest was Baigouyin River, which is near the residential area. The results indicated that the content of ammonia nitrogen in the interstitial water was between 5.24 and 10.64 mg·L-1, which was 10 times that of the overlying water, and endogenous pollution in the former was severe. The nitrate nitrogen content ranged from 0.36 to 0.79 mg·L-1. The total dissolved nitrogen content was between 5.36 and 12.02 mg·L-1, which was 5 times higher than that of the overlying water. The total dissolved phosphorus was between 0.03 and 0.3 mg·L-1. According to integrated pollution index, the degree of interstitial water pollution was much higher than that of overlying water, and the sampling points are seriously polluted. The exchange flux analysis of NH4+-N, TDN, and TDP demonstrated that the diffusion flux of NH4+-N was between 1.71 and 7.43 mg·(m2·d)-1, and the diffusion rate of endogenous ammonia nitrogen to the overlying water was fastest in Fu River, the absorbing river in Baoding. The diffusion flux of total dissolved nitrogen was lower in the Baigouyin River, and the other five sample points averaged 9.11 mg·(m2·d)-1. In summer, the dissolved oxygen was lower and the water-sediment had a larger concentration difference, which led to massive nitrogen nutrient of sediment in anaerobic conditions released to the overlying water in great quantities that caused the serious pollution. The diffusion flux of dissolved total phosphorus showed that the sediment of Pinghe River acted as a "sink" of phosphorus nutrients, and the other sampling points ranged from 0.03 to 0.16 mg·(m2·d)-1, showing the state of phosphorus nutrient released upward to the overlying water. Finally, diffusion flux indicated that endogenous pollutants are crucial sources of overlying water pollutants. In order to effectively control the water quality in the entrance area, desilting the nitrogen and phosphorus nutrient salt of sediment is urgently required.

[Temporal and Spatial Evolution Characteristics of DOM Spectra in Sediment Interstitial Water in Typical Zones of Baiyangdian Lake].

The sources and distribution of dissolved organic matter (DOM) in the interstitial water of Baiyangdian Lake sediments were analyzed using the ultraviolet-visible absorption spectrum (UV-vis) method and three-dimensional excitation emission matrix fluorescence spectroscopy-parallel factor analysis (EEM-PARAFAC). Results showed that the DOM concentrations and molecular weight were significantly higher in summer than in spring and autumn, based on a254 and E2/E3 values. Three protein-like substance (C1, C2, and C3) and two humic-like substances (C4, C5) were identified with the PARAFAC model. Moreover, protein-like substances accounted for the majority of DOM, reaching (63.56±16.07)%. Total DOM fluorescence intensity, the fluorescence intensity of each component, and the relative abundance exhibited significant spatial variation among the different functional zones in Baiyangdian Lake. Protein-like substances were mainly found in the breeding area, whereas humic-like substances mainly occurred in the natural area. The high BIX, FI, ß:α, and low HIX indicated that DOM in sediment interstitial water exhibited low humification and highly autochthonous characteristics. Moreover, the perfect regression equations between water quality and the fluorescent components could provide a useful reference for managers aiming to protect the ecosystem of Baiyangdian Lake.

LncRNA NEAT1 promotes autophagy in MPTP-induced Parkinson's disease through stabilizing PINK1 protein.

BACKGROUND: Long non-coding RNA nuclear paraspeckle assembly transcript 1 (lncRNA NEAT1) was found to be closely related to the pathological changes in brain and nervous system. However, the role of NEAT1 and its potential mechanism in Parkinson's disease (PD) largely remain uncharacterized. METHODS: In this study, PD mouse model was established by intraperitoneal injection of MPTP. The numbers of TH + neurons, NEAT1 expression and the level of PINK1, LC3-II, LC3-I protein were assessed in PD mice. SH-SY5Y cells were treated with MPP+ as PD cell model. RNA pull-down assay was used to identify the interaction between NEAT1 and PINK1 in vitro. The endogenous expression of NEAT1 was modified by lentiviral vector carrying interference sequence for NEAT1 in vivo. RESULTS: The numbers of TH+ neurons significantly decreased in PD mice compared with the control. The expressions of NEAT1, PINK1 protein and LC3-II/LC3-I level were increased by MPTP in vitro and in vivo. Moreover, NEAT1 positively regulated the protein level of PINK1 through inhibition of PINK1 protein degradation. And NEAT1 mediated the effects of MPP+ on SH-SY5Y cells through stabilization of PINK1 protein. The results of in vivo experiments revealed that NEAT1 knockdown could effectively suppress MPTP-induced autophagy in vivo that alleviated dopaminergic neuronal injury. CONCLUSION: LncRNA NEAT1 promoted the MPTP-induced autophagy in PD through stabilization of PINK1 protein.

BMP2 promotes the differentiation of neural stem cells into dopaminergic neurons in vitro via miR-145-mediated upregulation of Nurr1 expression.

BACKGROUND: Neural stem cells (NSCs) are pluripotent and self-renewing cells which could differentiate into diverse types of neural cells, such as dopaminergic (DA) neurons, the loss of which is the typical characteristic of Parkinson's disease (PD). This study aimed to examine the molecular mechanisms of BMP2-mediating NSCs differentiation into DA neurons. METHODS: Different concentrations of BMP2 were used to induce the differentiation of NSCs into DA neurons, which were characterized by the number and the neurite lengths of tyrosine hydroxylase (TH)+ and dopamine transporter (DAT)+ neurons by immunocytochemistry. qRT-PCR and Western blot were performed to explore the expression of miR-145 and Nurr1. The methylation level of miR-145 promoter was examined by DNA methylation analyses. The regulation of miR-145 on Nurr1 was detected by Dual-Luciferase reporter assay. RESULTS: The number of TH+ and DAT+ neurons were significantly increased in NSCs treated with 20 and 100 ng/ml of BMP2, as well as the neurite lengths of TH+ and DAT+ neurons. The reduced level of miR-145 and up-regulated Nurr1 were observed in NSCs induced by BMP2. The hypermethylation level of miR-145 promoter down-regulated the expression of miR-145 in NSCs pretreated with BMP2, which was regulated by DNMT3b. Luciferase reporter assay showed that Nurr1 was a direct target of miR-145. miR-145 overexpression restrained the differentiating effect of BMP2. Moreover, overexpression of Nurr1 abrogated this effect of miR-145 overexpression. CONCLUSION: Our results showed that BMP2 promoted the differentiation of NSCs into DA neurons in vitro and miR-145 and Nurr1 were involved in the neurotrophic effects of BMP2.