Differential Mechanisms of Microbial As(III) and Sb(III) Oxidation and Their Contribution to Tailings Reclamation.

Mine tailings are extremely oligotrophic environments frequently contaminated with elevated As and Sb, making As(III) and Sb(III) oxidation potentially important energy sources for the tailing microbiome. Although they have been proposed to share similar metabolic pathways, a systemic comparison of the As(III) and Sb(III) oxidation mechanisms and energy utilization efficiencies requires further elucidation. In this study, we employed a combination of physicochemical, molecular, and bioinformatic analyses to compare the kinetic and genetic mechanisms of As(III) and Sb(III) oxidation as well as their respective energy efficiencies for fueling the key nutrient acquisition metabolisms. Thiobacillus and Rhizobium spp. were identified as functional populations for both As(III) and Sb(III) oxidation in mine tailings by DNA-stable isotope probing. However, these microorganisms mediated As(III) and Sb(III) oxidation via different metabolic pathways, resulting in preferential oxidation of Sb(III) over As(III). Notably, both As(III) and Sb(III) oxidation can facilitate nitrogen fixation and phosphate solubilization in mine tailings, with Sb(III) oxidation being more efficient in powering these processes. Thus, this study provided novel insights into the microbial As(III) and Sb(III) oxidation mechanisms and their respective nutrient acquisition efficiencies, which may be critical for the reclamation of mine tailings.

Phototrophic Nitrogen Fixation, a Neglected Biogeochemical Process in Mine Tailings?

Biological nitrogen fixation (BNF) has important ecological significance in mine tailing by contributing to the initial accumulation of nitrogen. In addition to chemolithotrophic and heterotrophic BNF, light may also fuel BNF in oligotrophic mine tailings. However, knowledge regarding the occurrence and ecological significance of this biogeochemical process in mine tailings remains ambiguous. The current study observed phototrophic BNF in enrichment cultures established from three primary successional stages (i.e., original tailings, biological crusts, and pioneer plants) of tailings. Notably, phototrophic BNF in tailings may be more active at vegetation stages (i.e., biological crusts and pioneering plants) than in bare tailings. DNA-stable isotope probing identified Roseomonas species as potential aerobic anoxygenic phototrophs responsible for phototrophic BNF. Furthermore, metagenomic binning as well as genome mining revealed that Roseomonas spp. contained essential genes involved in nitrogen fixation, anoxygenic photosynthesis, and carbon fixation, suggesting their genetic potential to mediate phototrophic BNF. A causal inference framework equipped with the structural causal model suggested that the enrichment of putative phototrophic diazotrophic Roseomonas may contribute to an elevated total nitrogen content during primary succession in these mine tailings. Collectively, our findings suggest that phototrophic diazotrophs may play important roles in nutrient accumulation and hold the potential to facilitate ecological succession in tailings.

Microbial Sulfur and Arsenic Oxidation Facilitate the Establishment of Biocrusts during Reclamation of Degraded Mine Tailings.

Degraded tailings generated by the mining of metal ores are major environmental threats to the surrounding ecosystems. Tailing reclamation, however, is often impeded due to adverse environmental conditions, with depleted key nutrients (i.e., nitrogen (N) and phosphorus (P)) and elevated sulfur and metal(loid) concentrations. Formation of biocrusts may significantly accelerate nutrient accumulation and is therefore an essential stage for tailing reclamation. Although suggested to play an important role, the microbial community composition and key metabolisms in biocrusts remain largely unknown and are therefore investigated in the current study. The results suggested that sulfur and arsenic oxidation are potential energy sources utilized by members of predominant biocrust bacterial families, including Beijerinckiaceae, Burkholderiaceae, Hyphomicrobiaceae, and Rhizobiaceae. Accordingly, the S and As oxidation potentials are elevated in biocrusts compared to those in their adjacent tailings. Biocrust growth, as proxied by chlorophyll concentrations, is enhanced in treatments supplemented with S and As. The elevated biocrust growth might benefit from nutrient acquisition services (i.e., nitrogen fixation and phosphorus solubilization) fueled by microbial sulfur and arsenic oxidation. The current study suggests that sulfur- and arsenic-oxidizing microorganisms may play important ecological roles in promoting biocrust formation and facilitating tailing reclamation.

Effects of different drying methods on the contents of active ingredients of Saposhnikovia divaricata (Turcz.) Schischk and optimization of the drying process by response surface methodology.

INTRODUCTION: Saposhnikovia divaricata (Turcz.) Schischk is one of the most widely used Chinese herbs worldwide. It has anti-inflammatory and analgesic properties and hence has a high clinical value. As the moisture level in S. divaricata is high after harvest, it requires drying. OBJECTIVE: We aimed to find a scientific drying method and optimize the drying conditions of the best drying method of S. divaricata using response surface methodology (RSM). METHODOLOGY: The effects of 4 different drying methods on the contents of prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisamminol, and sec-O-glucosylhamaudol were determined using high-performance liquid chromatography. Chroma, the rehydration ratio, and active component content were used as indices, and slice thickness, drying temperature, and drying time were used as independent variables to optimize the drying conditions of the optimal drying method of S. divaricata using RSM combined with the Box-Behnken design. RESULTS: The results showed that the optimal drying conditions were as follows: slice thickness, 4.00 mm; drying temperature, 60°C; and drying time, 15 h. CONCLUSION: Under optimal drying conditions, the measured values were extremely close to the predicted values. The results of variance analysis showed that the model had a high degree of fit and the drying conditions of S. divaricata were optimized successfully.

Effects of different post-harvest processing methods on changes in the active ingredients of licorice based on LC-MS and plant metabolomics.

INTRODUCTION: Licorice, the dried roots and rhizomes of the Glycyrrhiza uralensis Fisch., holds a prominent status in various formulations within the realm of Chinese medicinal practices. The traditional processing methods of licorice hinder quality assurance, thus prompting Chinese medicine researchers to focus on the fresh processing methods to enhancing processing efficiency and quality. OBJECTIVE: This study aimed to identify the differential compounds of licorice between traditional and fresh processing methods and provide a scientific basis for the fresh processing of licorice and for further research on the processing mechanism. METHODOLOGY: A methodology integrating ultra-performance liquid chromatography with quadrupole-time-of-flight tandem mass spectrometry combined with multivariate statistical analysis was employed to characterize the differential compounds present in licorice between traditional processing and fresh processing. RESULTS: The results derived from principal component analysis and heat map analyses underscored significant differences in the content of bioactive compounds between the two processing methods. By applying conditions of VIP > 1.5 and p < 0.05, a total of 38 differential compounds were identified through t tests, and the transformation mechanisms of select compounds were illustrated. CONCLUSION: The adoption of fresh processing techniques not only improved processing efficiency but also significantly enhanced the preservation of bioactive compounds within licorice. This research has established a rapid and efficient analytical method for the identification of differential compounds present in differently processed licorice products.

Anion-π Interaction Powered Perrhenate Recognition and Extraction in Aqueous Media.

Selective anion recognition and extraction in aqueous media is a challenging research topic, and the anion-π interaction is an undetermined solution for the development of anion sorbent materials with better affinity and selectivity. Here, noncovalent anion-π interaction was introduced as the driving force for this purpose. A cage-based 2D cationic metal-organic framework, IPM-21, is featured with porous channels formed by complementary V-shape electron-deficient cavities. This 3D rhombic electron-deficient cavity can bind two anions with the clipped π-acidic surfaces, exhibiting much higher affinity toward ReO4- due to the strong complementary effect. This cavity was forced to expand its opening size to seamlessly adopt the ReO4- anion with a large volume. Experimental results found that the binding energy of IPM-21 with ReO4- is around 2.3 kJ/mol higher than that with ClO4-. Parts per million levels of the ReO4- anion in aqueous media can be effectively extracted by IPM-21 with a removal up to 99%, even with mixed competing anions. IPM-21 can be easily recycled and reused by treatment with high concentration aqueous NaClO4. Due to the extremely low interlamellar interaction, the IPM-21 crystal exhibited enhanced ReO4- extraction performance with the recycling times due to self-exfoliation; as a result, ultrathin IPM-21 nanosheets with large lateral sizes were produced in this process.

Chemolithotrophic Biological Nitrogen Fixation Fueled by Antimonite Oxidation May Be Widespread in Sb-Contaminated Habitats.

Nitrogen (N) deficiency in mining-contaminated habitats usually hinders plant growth and thus hampers tailing revegetation. Biological N fixation (BNF) is an essential biogeochemical process that contributes to the initial accumulation of N in oligotrophic mining-contaminated regions. Previous studies reported that chemolithotrophic rather than heterotrophic diazotrophs frequently dominated in the mining-contaminated regions. Chemolithotrophic diazotrophs may utilize elements abundant in such habitats (e.g., sulfur (S), arsenic (As), and antimony (Sb)) as electron donors to fix N2. BNF fueled by the oxidation of S and As has been detected in previous studies. However, BNF fueled by Sb(III) oxidation (Sb-dependent BNF) has never been reported. The current study observed the presence of Sb-dependent BNF in slurries inoculated from Sb-contaminated habitats across the South China Sb belt, suggesting that Sb-dependent BNF may be widespread in this region. DNA-stable isotope probing identified bacteria associated with Rhodocyclaceae and Rhizobiaceae as putative microorganisms responsible for Sb-dependent BNF. Furthermore, metagenomic-binning demonstrated that Rhodocyclaceae and Rhizobiaceae contained essential genes involved in Sb(III) oxidation, N2 fixation, and carbon fixation, suggesting their genetic potential for Sb-dependent BNF. In addition, meta-analysis indicated that these bacteria are widespread among Sb-contaminated habitats with different niche preferences: Rhodocyclaceae was enriched in river sediments and tailings, while Rhizobiaceae was enriched only in soils. This study may broaden our fundamental understanding of N fixation in Sb-mining regions.

Physiological Characteristics and Transcriptome Analysis of Exogenous Brassinosteroid-Treated Kiwifruit.

Brassinosteroids (BRs) play pivotal roles in improving plant stress tolerance. To investigate the mechanism of BR regulation of salt tolerance in kiwifruit, we used 'Hongyang' kiwifruit as the test material. We exposed the plants to 150 mmol/L NaCl stress and irrigated them with exogenous BR (2,4-epibrassinolide). The phenotypic analysis showed that salt stress significantly inhibited photosynthesis in kiwifruit, leading to a significant increase in the H2O2 content of leaves and roots and a significant increase in Na+/K+, resulting in oxidative damage and an ion imbalance. BR treatment resulted in enhanced photosynthesis, reduced H2O2 content, and reduced Na+/K+ in leaves, alleviating the salt stress injury. Furthermore, transcriptome enrichment analysis showed that the differentially expressed genes (DEGs) related to BR treatment are involved in pathways such as starch and sucrose metabolism, pentose and glucuronate interconversions, and plant hormone signal transduction, among others. Among the DEGs involved in plant hormone signal transduction, those with the highest expression were involved in abscisic acid signal transduction. Moreover, there was a significant increase in the expression of the AcHKT1 gene, which regulates ion transduction, and the antioxidant enzyme AcFSD2 gene, which is a key gene for improving salt tolerance. The data suggest that BRs can improve salt tolerance by regulating ion homeostasis and reducing oxidative stress.

Metabolic potentials of members of the class Acidobacteriia in metal-contaminated soils revealed by metagenomic analysis.

The relative abundance of Acidobacteriia correlated positively with the concentrations of arsenic (As), mercury (Hg), chromium (Cr), copper (Cu) and other metals, suggesting their adaptation of the metal-rich environments. Metagenomic binning reconstructed 29 high-quality metagenome-assembled genomes (MAGs) associated with Acidobacteriia, providing an opportunity to study their metabolic potentials. These MAGs contained genes to transform As, Hg and Cr through oxidation, reduction, efflux and demethylation, suggesting the potential of Acidobacteriia to transform such metal(loid)s. Additionally, genes associated with alleviation of acidic and metal stress were also detected in these MAGs. Acidobacteriia may have the capabilities to resist or transform metal(loid)s in acidic metal-contaminated sites. Moreover, these genes encoding metal transformation could be also identified in the Acidobacteriia-associated MAGs from five additional metal-contaminated sites across Southwest China, as well as Acidobacteriia-associated reference genomes from the NCBI database, suggesting that the capability of metal transformation may be widespread among Acidobacteriia members. This discovery provides an understanding of metabolic potentials of the Acidobacteriia in acidic metal-rich sites.

Oxidation of organoarsenicals and antimonite by a novel flavin monooxygenase widely present in soil bacteria.

Arsenic can be biomethylated to form a variety of organic arsenicals differing in toxicity and environmental mobility. Trivalent methylarsenite (MAs(III)) produced in the methylation process is more toxic than inorganic arsenite (As(III)). MAs(III) also serves as a primitive antibiotic and, consequently, some environmental microorganisms have evolved mechanisms to detoxify MAs(III). However, the mechanisms of MAs(III) detoxification are not well understood. In this study, we identified an arsenic resistance (ars) operon consisting of three genes, arsRVK, that contribute to MAs(III) resistance in Ensifer adhaerens ST2. ArsV is annotated as an NADPH-dependent flavin monooxygenase with unknown function. Expression of arsV in the arsenic hypersensitive Escherichia coli strain AW3110Δars conferred resistance to MAs(III) and the ability to oxidize MAs(III) to MAs(V). In the presence of NADPH and either FAD or FMN, purified ArsV protein was able to oxidize both MAs(III) to MAs(V) and Sb(III) to Sb(V). Genes with arsV-like sequences are widely present in soils and environmental bacteria. Metagenomic analysis of five paddy soils showed the abundance of arsV-like sequences of 0.12-0.25 ppm. These results demonstrate that ArsV is a novel enzyme for the detoxification of MAs(III) and Sb(III) and the genes encoding ArsV are widely present in soil bacteria.

In Situ Anchoring Co-N-C Nanoparticles on Co4 N Nanosheets toward Ultrastable Flexible Self-Supported Bifunctional Oxygen Electrocatalyst Enables Recyclable Zn-Air Batteries Over 10 000 Cycles and Fast Charging.

Zn-air batteries (ZABs) are very promising for flexible energy storage, but their application is limited to the primary battery. Developing an efficient and non-noble metal cathode toward oxygen reduction/evolution reactions (ORR/OER) is of great significance for the commercial application of rechargeable ZABs. Herein, a flexible self-supported integrated bifunctional cathode is presented in which the Co-N-C nanoparticles are in situ anchored on Co4 N nanosheets via a facile and scalable strategy. Benefiting from integrated 3D architecture with adequate active sites, porous structure, high conductivity originating from the metal substrate, and the synergistic effects of Co-N-C and Co4 N, the cathode exhibits excellent bifunctional activity (low overpotential of 275 mV at 10 mA cm-2 for OER, high half-wave potential of 0.833 V for ORR), and ultralong durability for ORR/OER in the alkaline medium. Impressively, this cathode enables the recyclable aqueous ZABs a record overall lifespan over 10 000 cycles at 20 mA cm-2 , and a superior fast-charging feature at an ultrahigh charging current density of 100 mA cm-2 . Furthermore, such a flexible integrated cathode can be directly used as a self-supported cathode for flexible solid-state ZABs, with excellent reversibility for 300 cycles, demonstrating its feasibility for practical application.

Synergistic Impacts of Arsenic and Antimony Co-contamination on Diazotrophic Communities.

Nitrogen (N) shortage poses a great challenge to the implementation of in situ bioremediation practices in mining-contaminated sites. Diazotrophs can fix atmospheric N2 into a bioavailable form to plants and microorganisms inhabiting adverse habitats. Increasing numbers of studies mainly focused on the diazotrophic communities in the agroecosystems, while those communities in mining areas are still not well understood. This study compared the variations of diazotrophic communities in composition and interactions in the mining areas with different extents of arsenic (As) and antimony (Sb) contamination. As and Sb co-contamination increased alpha diversities and the abundance of nifH encoding the dinitrogenase reductase, while inhibited the diazotrophic interactions and substantially changed the composition of communities. Based on the multiple lines of evidence (e.g., the enrichment analysis of diazotrophs, microbe-microbe network, and random forest regression), six diazotrophs (e.g., Sinorhizobium, Dechloromonas, Trichormus, Herbaspirillum, Desmonostoc, and Klebsiella) were identified as keystone taxa. Environment-microbe network and random forest prediction demonstrated that these keystone taxa were highly correlated with the As and Sb contamination fractions. All these results imply that the above-mentioned diazotrophs may be resistant to metal(loid)s.

Effects of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS) on Soil Microbial Community.

The extensive application of perfluoroalkyl and polyfluoroalkyl substances (PFASs) causes their frequent detection in various environments. In this work, two typical PFASs, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), are selected to investigate their effects on soil microorganisms. Microbial community structure and microbe-microbe relationships were investigated by high-throughput sequencing and co-occurrence network analysis. Under 90 days of exposure, the alpha-diversity of soil microbial communities was increased with the PFOS treatment, followed by the PFOA treatment. The exposure of PFASs substantially changed the compositions of soil microbial communities, leading to the enrichment of more PFASs-tolerant bacteria, such as Proteobacteria, Burkholderiales, and Rhodocyclales. Comparative co-occurrence networks were constructed to investigate the microbe-microbe interactions under different PFASs treatments. The majority of nodes in the PFOA and PFOS networks were associated with the genus Azospirillum and Hydrogenophaga, respectively. The LEfSe analysis further identified a set of biomarkers in the soil microbial communities, such as Azospirillum, Methyloversatilis, Hydrogenophaga, Pseudoxanthomonas, and Fusibacter. The relative abundances of these biomarkers were also changed by different PFASs treatments. Functional gene prediction suggested that the microbial metabolism processes, such as nucleotide transport and metabolism, cell motility, carbohydrate transport and metabolism, energy production and conversion, and secondary metabolites biosynthesis transport and catabolism, might be inhibited under PFAS exposure, which may further affect soil ecological services.

Serratia spp. Are Responsible for Nitrogen Fixation Fueled by As(III) Oxidation, a Novel Biogeochemical Process Identified in Mine Tailings.

Biological nitrogen fixation (BNF) has important environmental implications in tailings by providing bioavailable nitrogen to these habitats and sustaining ecosystem functions. Previously, chemolithotrophic diazotrophs that dominate in mine tailings were shown to use reduced sulfur (S) as the electron donor. Tailings often contain high concentrations of As(III) that might function as an alternative electron donor to fuel BNF. Here, we tested this hypothesis and report on BNF fueled by As(III) oxidation as a novel biogeochemical process in addition to BNF fueled by S. Arsenic (As)-dependent BNF was detected in cultures inoculated from As-rich tailing samples derived from the Xikuangshan mining area in China, as suggested by nitrogenase activity assays, quantitative polymerase chain reaction, and 15N2 enrichment incubations. As-dependent BNF was also active in eight other As-contaminated tailings and soils, suggesting that the potential for As-dependent BNF may be widespread in As-rich habitats. DNA-stable isotope probing identified Serratia spp. as the bacteria responsible for As-dependent BNF. Metagenomic binning indicated that the essential genes for As-dependent BNF [i.e., nitrogen fixation, As(III) oxidation, and carbon fixation] were present in Serratia-associated metagenome-assembled genomes. Over 20 Serratia genomes obtained from NCBI also contained essential genes for both As(III) oxidation and BNF (i.e., aioA and nifH), suggesting that As-dependent BNF may be a widespread metabolic trait in Serratia spp.

Immobile Iron-Rich Particles Promote Arsenic Retention and Regulate Arsenic Biotransformation in Treatment Wetlands.

Remediation of arsenic (As)-contaminated wastewater by treatment wetlands (TWs) remains a technological challenge due to the low As adsorption capacity of wetland substrates and the release of adsorbed As to pore water. This study investigated the feasibility of using immobile iron-rich particles (IIRP) to promote As retention and to regulate As biotransformation in TWs. Iron-rich particles prepared were immobilized in the interspace of a gravel substrate. TWs with IIRP amendment (IIRP-TWs) achieved a stable As removal efficiency of 63 ± 4% over 300 days, while no As removal or release was observed in TWs without IIRP after 180 days of continuous operation. IIRP amendment provided additional adsorption sites and increased the stability of adsorbed As due to the strong binding affinity between As and Fe oxides. Microbially mediated As(III) oxidation was intensified by iron-rich particles in the anaerobic bottom layer of IIRP-TWs. Myxococcus and Fimbriimonadaceae were identified as As(III) oxidizers. Further, metagenomic binning suggested that these two bacterial taxa may have the capability for anaerobic As(III) oxidation. Overall, this study demonstrated that abiotic and biotic effects of IIRP contribute to As retention in TWs and provided insights into the role of IIRP for the remediation of As contamination.

Mycobacteriaceae Mineralizes Micropolyethylene in Riverine Ecosystems.

Microplastic (MP) contamination is a serious global environmental problem. Plastic contamination has attracted extensive attention during the past decades. While physiochemical weathering may influence the properties of MPs, biodegradation by microorganisms could ultimately mineralize plastics into CO2. Compared to the well-studied marine ecosystems, the MP biodegradation process in riverine ecosystems, however, is less understood. The current study focuses on the MP biodegradation in one of the world's most plastic contaminated rivers, Pearl River, using micropolyethylene (mPE) as a model substrate. Mineralization of 13C-labeled mPE into 13CO2 provided direct evidence of mPE biodegradation by indigenous microorganisms. Several Actinobacteriota genera were identified as putative mPE degraders. Furthermore, two Mycobacteriaceae isolates related to the putative mPE degraders, Mycobacterium sp. mPE3 and Nocardia sp. mPE12, were retrieved, and their ability to mineralize 13C-mPE into 13CO2 was confirmed. Pangenomic analysis reveals that the genes related to the proposed mPE biodegradation pathway are shared by members of Mycobacteriaceae. While both Mycobacterium and Nocardia are known for their pathogenicity, these populations on the plastisphere in this study were likely nonpathogenic as they lacked virulence factors. The current study provided direct evidence for MP mineralization by indigenous biodegraders and predicted their biodegradation pathway, which may be harnessed to improve bioremediation of MPs in urban rivers.

Root microbiome assembly of As-hyperaccumulator Pteris vittata and its efficacy in arsenic requisition.

The assemblage of root-associated microorganisms plays important roles in improving their capability to adapt to environmental stress. Metal(loid) hyperaccumulators exhibit disparate adaptive capability compared to that of non-hyperaccumulators when faced with elevated contents of metal(loid)s. However, knowledge of the assemblage of root microbes of hyperaccumulators and their ecological roles in plant growth is still scarce. The present study used Pteris vittata as a model plant to study the microbial assemblage and its beneficial role in plant growth. We demonstrated that the assemblage of microbes from the associated bulk soil to the root compartment was based on their lifestyles. We used metagenomic analysis and identified that the assembled microbes were primarily involved in root-microbe interactions in P. vittata root. Notably, we identified that the assembled root microbiome played an important role in As requisition, which promoted the fitness and growth of P. vittata. This study provides new insights into the root microbiome and potential valuable knowledge to understand how the root microbiome contributes to the fitness of its host.

Diversity and Metabolic Potentials of As(III)-Oxidizing Bacteria in Activated Sludge.

Biological arsenite [As(III)] oxidation is an important process in the removal of toxic arsenic (As) from contaminated water. However, the diversity and metabolic potentials of As(III)-oxidizing bacteria (AOB) responsible for As(III) oxidation in wastewater treatment facilities are not well documented. In this study, two groups of bioreactors inoculated with activated sludge were operated under anoxic or oxic conditions to treat As-containing synthetic wastewater. Batch tests of inoculated sludges from the bioreactors further indicated that microorganisms could use nitrate or oxygen as electron acceptors to stimulate biological As(III) oxidation, suggesting the potentials of this process in wastewater treatment facilities. In addition, DNA-based stable isotope probing (DNA-SIP) was performed to identify the putative AOB in the activated sludge. Bacteria associated with Thiobacillus were identified as nitrate-dependent AOB, while bacteria associated with Hydrogenophaga were identified as aerobic AOB in activated sludge. Metagenomic binning reconstructed a number of high-quality metagenome-assembled genomes (MAGs) associated with the putative AOB. Functional genes encoding As resistance, As(III) oxidation, denitrification, and carbon fixation were identified in these MAGs, suggesting their potentials for chemoautotrophic As(III) oxidation. In addition, the presence of genes encoding secondary metabolite biosynthesis and extracellular polymeric substance metabolism in these MAGs may facilitate the proliferation of these AOB in activated sludge and enhance their capacity for As(III) oxidation. IMPORTANCE AOB play an important role in the removal of toxic arsenic from wastewater. Most of the AOB have been isolated from natural environments. However, knowledge regarding the structure and functional roles of As(III)-oxidizing communities in wastewater treatment facilities is not well documented. The combination of DNA-SIP and metagenomic binning provides an opportunity to elucidate the diversity of in situ AOB community inhabiting the activated sludges. In this study, the putative AOB responsible for As(III) oxidation in wastewater treatment facilities were identified, and their metabolic potentials, including As(III) oxidation, denitrification, carbon fixation, secondary metabolite biosynthesis, and extracellular polymeric substance metabolism, were investigated. This observation provides an understanding of anoxic and/or oxic AOB during the As(III) oxidation process in wastewater treatment facilities, which may contribute to the removal of As from contaminated water.

Identification of Antimonate Reducing Bacteria and Their Potential Metabolic Traits by the Combination of Stable Isotope Probing and Metagenomic-Pangenomic Analysis.

Microorganisms play an important role in altering antimony (Sb) speciation, mobility, and bioavailability, but the understanding of the microorganisms responsible for Sb(V) reduction has been limited. In this study, DNA-stable isotope probing (DNA-SIP) and metagenomics analysis were combined to identify potential Sb(V)-reducing bacteria (SbRB) and predict their metabolic pathways for Sb(V) reduction. Soil slurry cultures inoculated with Sb-contaminated paddy soils from two Sb-contaminated sites demonstrated the capability to reduce Sb(V). DNA-SIP identified bacteria belonging to the genera Pseudomonas and Geobacter as putative SbRB in these two Sb-contaminated sites. In addition, bacteria such as Lysinibacillus and Dechloromonas may potentially participate in Sb(V) reduction. Nearly complete draft genomes of putative SbRB (i.e., Pseudomonas and Geobacter) were obtained, and the genes potentially responsible for arsenic (As) and Sb reduction (i.e., respiratory arsenate reductase (arrA) and antimonate reductase (anrA)) were examined. Notably, bins affiliated with Geobacter contained arrA and anrA genes, supporting our hypothesis that they are putative SbRB. Further, pangenomic analysis indicated that various Geobacter-associated genomes obtained from diverse habitats also contained arrA and anrA genes. In contrast, Pseudomonas may use a predicted DMSO reductase closely related to sbrA (Sb(V) reductase gene) clade II to reduce Sb(V), which may need further experiments to verify. This current work represents a demonstration of using DNA-SIP and metagenomic-binning to identify SbRB and their key genes involved in Sb(V) reduction and provides valuable data sets to link bacterial identities with Sb(V) reduction.

Simiao Qingwen Baidu decoction inhibits Epstein-Barr virus-induced B lymphoproliferative disease and lytic viral replication.

CONTEXT: Simiao Qingwen Baidu decoction (SQBD), a traditional Chinese medicine prescription, can ameliorate Epstein-Barr virus (EBV) induced disease. However, its mechanism still remains unknown. OBJECTIVE: To detect the mechanism of SQBD in EBV-induced B lymphoproliferative disease in vitro. MATERIALS AND METHODS: Sprague-Dawley (SD) rats (n = 20) were given SQBD (10 mL/kg) by gavage once a day for 7 d. SQBD-containing serum was obtained from abdominal aortic blood of rats, and diluted with medium to obtain 5%, 10% or 20%-medicated serum. SD rats (n = 10) were given normal saline, and normal serum was collected as a control. EBV-transformed B cells (CGM1) were cultured in medium containing 5%, 10% or 20%-medicated serum. CGM1 cells were treated with normal serum as a control. Cell viability and apoptosis were examined. The expression and activity of proteins were assessed. RESULTS: We found that IC50 (83 ± 26.07%, 24 h; 69.88 ± 4.69%, 48 h) of 10% medicated serum was higher than that of 5% (25.47 ± 6.98%, 24 h; 21.62 ± 7.30%, 48 h) and 20%-medicated serum (51 ± 7.25%, 24 h; 56.03 ± 2.56%, 48 h). Moreover, SQBD promoted apoptosis of CGM1 cells by regulating EBV latency proteins expression. SQBD inhibited EBV-induced lytic viral replication. CONCLUSIONS: Our data confirmed that SQBD inhibits EBV-induced B lymphoproliferative disease and lytic viral replication. This work provides a theoretical basis for the mechanism of SQBD in EBV-induced B lymphoproliferative disease, and SQBD may be an effectively therapeutic drug for EBV-induced B lymphoproliferative disease.