Visible Light Photoactivity of g-C3N4/MoS2 Nanocomposites for Water Remediation of Hexavalent Chromium.

Water pollution has becoming an increasingly serious issue, and it has attracted a significant amount of attention from scholars. Here, in order remove heavy metal hexavalent chromium (Cr (VI)) from wastewater, graphitic carbon nitride (g-C3N4) was modified with molybdenum disulfide (MoS2) at different mass ratios via an ultrasonic method to synthesize g-C3N4/MoS2 (CNM) nanocomposites as photocatalysts. The nanocomposites displayed efficient photocatalytic removal of toxic hexavalent chromium (Cr (VI)) from water under UV, solar, and visible light irradiation. The CNM composite with a 1:2 g-C3N4 to MoS2 ratio achieved optimal 91% Cr (VI) removal efficiency at an initial 20 mg/L Cr (VI) concentration and pH 3 after 120 min visible light irradiation. The results showed a high pH range and good recycling stability. The g-C3N4/MoS2 nanocomposites exhibited higher performance compared to pure g-C3N4 due to the narrowed band gap of the Z-scheme heterojunction structure and effective separation of photo-generated electron-hole pairs, as evidenced by structural and optical characterization. Overall, the ultrasonic synthesis of g-C3N4/MoS2 photocatalysts shows promise as an efficient technique for enhancing heavy metal wastewater remediation under solar and visible light.

Recent Progress in Photocatalytic Degradation of Water Pollution by Bismuth Tungstate.

Photocatalysis has emerged as a highly promising, green, and efficient technology for degrading pollutants in wastewater. Among the various photocatalysts, Bismuth tungstate (Bi2WO6) has gained significant attention in the research community due to its potential in environmental remediation and photocatalytic energy conversion. However, the limited light absorption ability and rapid recombination of photogenerated carriers hinder the further improvement of Bi2WO6's photocatalytic performance. This review aims to present recent advancements in the development of Bi2WO6-based photocatalysts. It delves into the photocatalytic mechanism of Bi2WO6 and summarizes the achieved photocatalytic characteristics by controlling its morphology, employing metal and non-metal doping, constructing semiconductor heterojunctions, and implementing defective engineering. Additionally, this review explores the practical applications of these modified Bi2WO6 photocatalysts in wastewater purification. Furthermore, this review addresses existing challenges and suggests prospects for the development of efficient Bi2WO6 photocatalysts. It is hoped that this comprehensive review will serve as a valuable reference and guide for researchers seeking to advance the field of Bi2WO6 photocatalysis.

Transcriptome profiling of flower buds of male-sterile lines provides new insights into male sterility mechanism in alfalfa.

BACKGROUND: The use of heterosis to produce hybrid seeds is a challenge to breeding for improved crop yield. In previous studies, we isolated a male sterile alfalfa hybrid and successfully obtained a genetically stable alfalfa male sterile line through backcrossing, henceforth named MS-4. In this study, we used RNA-seq technology to analyze the transcriptome profiles of the male sterile line (MS-4) and the male fertile line (MF) of alfalfa to elucidate the mechanism of male sterility. RESULTS: We screened a total of 11,812 differentially expressed genes (DEGs) from both MS-4 and MF lines at three different stages of anther development. Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that these DEGs are mainly involved in processes such as energy metabolism, lipid and amino acid metabolism, carbohydrate metabolism, in addition to cell synthesis and aging. The results from protein-protein interaction (PPI) network analysis showed that the ribosomal protein (MS.Gene25178) was the core gene in the network. We also found that transcriptional regulation was an influential factor in the development of anthers. CONCLUSIONS: Our findings provide new insights into understanding of the fertility changes in the male sterile (MS-4) of alfalfa.

Stable Carbon Isotope Analysis of Hexachlorocyclohexanes by Liquid-Liquid Extraction Gas Chromatography Isotope Ratio Mass Spectrometry: Method Evaluation and Applications.

Compound specific isotope analysis (CSIA) and enantiomer specific isotope analysis (ESIA) are powerful tools for assessing the fate of hexachlorocyclohexanes (HCHs) in the environment. However, there is no systematic study on the CSIA and ESIA analysis test methods of the carbon isotopes of HCHs in water and soil environments, in particular the isotope fractionation in the pre-concentration process. We endeavored to test the compatibility of CSIA and ESIA with the liquid-liquid extraction method of HCHs in water. The results showed that there were negligible changes in the δ13C of HCHs after extraction, indicating that liquid-liquid extraction can be used as a pre-concentration method for the determination of δ13C of HCHs in water. The optimized method was validated and then applied to differentiate three HCHs from different manufacturers, to identify in situ degradation of HCHs of groundwater from a contaminated site and to resolve the carbon isotope fractionation occurring in the α-HCH oxidation by CaO2/Fe(II) Fenton system. The results showed that the same reagents from different manufacturers have different carbon isotope compositions, and different isomers from the same manufacturer also have different isotope compositions, showing useful evidence in identifying the source of HCHs. The more enriched δ13C in the down-gradient wells indicated that HCHs have undergone biodegradation or/and chemical reactions in the groundwater system of the site. Carbon isotopic enrichment factors (εC) of -1.90 ± 0.10‱ were obtained in the oxidation process. Hence, the method validated in this study has great potential as a method for identifying the degradation of HCHs in a water environment.

Ethylene-regulated leaf lifespan explains divergent responses of plant productivity to warming among three hydrologically different growing seasons.

Leaf senescence is known to be regulated by the plant hormone ethylene, but how leaf lifespan responds to global environmental change and links to ecosystem-level responses remains largely unexplored. Here we investigated the effects of climate warming and nitrogen addition on plant functional traits, plant hormone ethylene and net primary production in a 13-year field experiment in a desert steppe. Across the last 3 years of the experiment (2016-2018), plant productivity increased under warming only in 2016, when there was above normal precipitation, but consistently increased with nitrogen addition. Warming enhanced net photosynthesis, leaf nitrogen and ethylene production and reduced leaf lifespan in 2016 (a wet year), but not in 2017 (a drought year); the effect of warming in 2018 (a year with normal precipitation) was opposite to 2016, likely due to the below-normal precipitation in the mid-growing season in 2018. Nitrogen addition led to increases in leaf nitrogen, ethylene production and net photosynthesis, and declines in leaf lifespan in 2016 and 2018, but not in 2017. The ethylene-regulated lifespan was further evidenced by the addition of CoCl2 (an ethylene biosynthesis inhibitor) that reduced ethylene production and prolonged lifespan. Structural equation modeling showed that leaf lifespan had a negative effect on plant productivity, both directly and indirectly via its negative effect on net photosynthesis, across all 3 years. Our results demonstrate the divergent responses of leaf lifespan and, in turn, plant productivity to warming under inter-annual and intra-annual precipitation variation, thus linking plant hormone production, functional traits and ecosystem functioning in the face of global environmental change.

Comparative transcriptome between male fertile and male sterile alfalfa (Medicago varia).

Male sterility is an important factor in improving crop quality and yield through heterosis breeding. In this study, we analyzed the transcriptomes of male fertile (MF) and male sterile (MS) alfalfa flower buds using the Illumina HiSeq™ 4000 platform. A total of 54.05 million clean reads were generated and assembled into 65,777 unigenes with an average length of 874 bp. The differentially expressed genes (DEGs) between the MF and MS flowers at three stages of pollen development were identified, and there were 3832, 5678 and 5925 DEGs respectively in stages 1, 2 and 3. GO and KEGG functional enrichment analysis revealed 12, 12, 6 and 12 key branch-point genes involved in circadian rhythm, transcription factors, pollen development and flavonoid biosynthesis. Our findings provide novel insights into the mechanism of male sterility in alfalfa. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-01026-x.

Characterization of the microRNA408-LACCASE5 module as a regulatory axis for photosynthetic efficiency in Medicago ruthenica: implications for forage yield enhancement.

Medicago ruthenica is closely related to Medicago sativa, a commonly cultivated forage. Characterized by its high tolerance to environmental stress, M. ruthenica is a valuable genetic resource. However, low yield limits its large-scale utilization. Leaf morphology, an important agronomic trait, is closely related to forage yield and photosynthetic efficiency. In the presented study, "Correlation of Leaf Morphology and Photosynthetic Performance with Forage Yield in Medicago ruthenica: The Underlying Molecular Mechanisms," comprehensive data analysis revealed a significant positive association between leaf width and leaf area with forage yield in Medicago ruthenica (p < 0.05). The specific cultivar "Mengnong No.1 (MN No.1) had a large leaf area, and its physiological parameters related to photosynthetic characteristics were superior. Anatomical examination revealed that the leaves of MN No.1 had strong palisade tissue and compact cell structure. Subsequent investigations, utilizing small RNA and transcriptome sequencing, discerned critical miRNA-target gene networks that underpin the high photosynthetic efficiency in M. ruthenica. A total of 63 differentially expressed miRNAs (DEMs) were identified, inclusive of several well-characterized miRNAs such as miR408, miR171, and miR398. These miRNAs were predicted to target 55 genes (mRNAs), of which 6 miRNA-target gene pairs, particularly those involving miR408and miR171, exhibited inverse expression patterns. Among the six postulated miRNA-target gene pairs, the targeted cleavage of LACCASE5 (LAC5) by miR408 was conclusively validated through degradome sequencing, with the cleavage site pinpointed between the 9th and 10th nucleotides from the 5'end of miR408 via the 5'-RLM-RACE assay. Therefore, it is posited that the miR408-MrLAC5 module constitutes a central mechanism in fostering high photosynthetic efficiency in M. ruthenica. Moreover, these findings also provide valuable information for further study of the regulatory genes and miRNA functions of forage yield in legume forage.

Simultaneous catalytic oxidation of Hg0 and AsH3 over Fe-Ce co-doped TiO2 catalyst under low temperature and reducing atmosphere.

The Fe-Ce bimetal oxide-doped titanium dioxide composite was synthesized by the sol-gel method and the performance of the catalyst was investigated for the removal of Hg0 and AsH3 from yellow phosphorus flue gas under different conditions. Brunauer-Emmett-Teller (BET) analysis, high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the crystal structure and morphology of the structure, and the mechanisms for removing Hg0 and AsH3 from flue gas by catalytic oxidation were deduced. The results showed that the optimal calcination temperature of the Fe5Ce5Ti catalyst was 500 °C, and the optimal pH of the sol was 6. Under these conditions, the penetration adsorption capacity of the Fe5Ce5Ti catalyst for the removal of AsH3 and Hg0 was 385.5 mg g-1 and 2.178 mg g-1, respectively. According to characterization analysis, Fe and Ce are the main active components in the removal of Hg0 and AsH3, and the mixed oxides of Fe and Ce have a synergistic effect on the surface of the mixed oxide-doped catalyst, which can improve the dispersion of the active component on the surface of the catalyst, and then improve the removal efficiency of Hg0 and AsH3.

Chemical profile and quantitative comparison of constituents in different medicinal parts of Lactuca indica during varied harvest periods using UPLC-MS/MS method.

Lactuca indica L. cv. Mengzao (LIM), acknowledged as a pivotal "One Root of Medicine and Food", boasts dual applications in both culinary and medicinal domains. This research delves into the influence of various harvest periods (vegetative, budding, blossom, and fruiting) on distinct medicinal parts (roots, stems, leaves, flowers, and seeds) of LIM, employing plant metabolomics to assess its chemical constituents. A total of 66 chemical constituents were identified in LIM, with 11 chemical components emerging as potential markers for distinguish medicinal parts. Notably, nutritional organs exhibited elevated levels of cichoric acid, rutin and chlorogenic acid. Specifically, leaves during the budding stage displayed the highest chicoric acid content at 11.70 mg·g-1. Conversely, reproductive organs showed heightened concentrations of cichoric acid, rutin and chlorogenic acid, with seeds exhibiting the peak cichoric acid content at 4.53 mg g-1. This study enriches our understanding of LIM by offering novel insights into quality assessment and the comprehensive utilization of its diverse parts.

Effect of different regions on fermentation profiles, microbial communities, and their metabolomic pathways and properties in Italian ryegrass silage.

Introduction: Italian ryegrass is less studied in northern China due to high-quality forage grass has not been fully utilized. Full utilization of high-quality forage grass helps to alleviate the shortage of forage grass in winter and spring season and guarantee stable development of livestock production. Consequently, this study was aimed to evaluate the effects of different regions in northern China on the fermentative products, bacterial community compositions, and metabolic pathways and metabolites of Italian ryegrass silage. Methods: The Italian ryegrass was harvested from three regions (Ordos-WK; Hohhot-AK; Ulanqab-SYK) and ensiled for 60 days. Single molecule real-time (SMRT) sequencing and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) were used to analyze bacterial communities and metabolites, respectively. Results: After 60 d of fermentation, the SYK group had the lowest pH (4.67), the highest lactic acid contents (95.02 g/kg DM) and largest lactic acid bacteria populations (6.66 log10 cfu/g FM) among the treatment groups. In addition, the SYK group had the highest abundance of Lactiplantibacillus plantarum (63.98%). In SYK group, isoquinoline alkaloid biosynthesis was the significantly enriched (p < 0.05) and high-impact value (0.0225) metabolic pathway. In AK group, tryptophan metabolism the was the significantly enriched (p < 0.001) and high-impact value (0.1387) metabolic pathway. In WK group, citrate cycle (TCA cycle) was the significantly enriched (p < 0.001) and high-impact value (0.1174) metabolic pathway. Further, Lactiplantibacillus plantarum was positively correlated with cinnamic acid, tetranor 12-HETE, D-Mannitol, (2S)-2-amino-4-methylpentanoic acid L-Leucine, guanine, isoleucyl-aspartate and 3,4-Dihydroxyphenyl propanoate, but negatively correlated with isocitrate and D-mannose. Discussion: In conclusion, this study can improve our understanding of the ensiling microbiology and metabolomics in different regions to further regulate the fermentation products and promote livestock production.

Analysis of Chloroplast Genomes Provides Insights Into the Evolution of Agropyron.

Plants of the Agropyron genus are important pasture resources, and they also play important roles in the ecological restoration. Chloroplast genomes are inherited from maternal parents, and they are important for studying species taxonomy and evolution. In this study, we sequenced the complete chloroplast genomes of five typical species of the Agropyron genus (eg., A. cristatum × A. desertorum Fisch. Schult, A. desertorum, A. desertorum Fisch. Schult. cv. Nordan, A. michnoi Roshev, and A. mongolicum Keng) using the Illumina NovaSeq platform. We found that these five chloroplast genomes exhibit a typical quadripartite structure with a conserved genome arrangement and structure. Their chloroplast genomes contain the large single-copy regions (LSC, 79,613 bp-79,634 bp), the small single-copy regions (SSC, 12,760 bp-12,768 bp), and the inverted repeat regions (IR, 43,060 bp-43,090 bp). Each of the five chloroplast genomes contains 129 genes, including 38 tRNA genes, eight rRNA genes, and 83 protein-coding genes. Among them, the genes trnG-GCC, matK, petL, ccsA, and rpl32 showed significant nucleotide diversity in these five species, and they may be used as molecular markers in taxonomic studies. Phylogenetic analysis showed that A. mongolicum is closely related to A. michnoi, while others have a closer genetic relationship with the Triticum genus.

The sources and biogeochemical cycling of carbon in the Wudalianchi UNESCO Geopark volcanic system in Northeast China.

The biogeochemical cycling and response mechanisms of carbon within the Wudalianchi UNESCO Global Geopark were characterized by the isotopic compositions of dissolved inorganic carbon (δ13CDIC) and dissolved organic carbon in ground and surface (lake) waters and their relating carbon isotopic composition of soil (δ13CSOC) and sediment organic carbon (δ13Corg). In addition to mantle-derived CO2, the oxidation of organic matter was prevalent in shallow groundwater during the summer. Their associated degassing of CO2 produced higher pCO2 values than in autumn or winter and elevated δ13CDIC values. In summer, DIC in the epilimnion showed a wide range of δ13CDIC from - 8.4 to 2.6‰. Waters in open-lake areas with relatively positive δ13CDIC values and the low levels of pCO2 were primarily influenced by CO2 degassing. Photosynthesis elevated the δ13CDIC values and led to minimal pCO2 levels in closed lake areas. Isotopically, δ13Corg was found to be positively related to δ13CSOC. In addition, lake bed sediments generally had lower concentrations and larger δ13C values of organic carbon than the surrounding soils. These results suggest that 12CO2 derived from the degradation of sediment was preferentially utilized by phytoplankton in the epilimnion during photosynthesis. The remaining 13C-rich organic matter was retained in the sediment. Since 2000, δ13Corg increased in lake 3 over time, reflecting the input of sewage and land use changes associated with a resort used for tourism. The values of δ13Corg in lake 5, distant from the resort, did not change substantially, indicating minimal human impacts.

The sources and dispersal of nitrate in multiple waters, constrained by multiple isotopes, in the Wudalianchi region, northeast China.

The Wudalianchi scenic area in NE China has been named an UNESCO "Global Geopark" and "Biosphere Reserve." During this investigation, the sources of nitrate and the hydrologic system through which it is dispersed were assessed using geochemical data and a multiple isotopic approach. The cold waters from the south and north springs originated from the deep subsurface. Isotopically, these waters exhibited relatively negative δD and δ18O values and nitrate in the water was substantially depleted 15N, suggesting that the mineral water was primarily derived from depth. Lakes within the Wudalianchi region were primarily composed of water from these deep mineral springs and precipitation. Chemical fertilizers were the primary source of nitrate to the Wudalianchi lakes. Groundwater was found in shallow mineral springs and wells plotted above the local meteoric water line, implying that shallow groundwater was primarily derived from precipitation. Elevated concentrations of nitrate in shallow mineral springs and well waters during the summer, autumn, and winter suggest that shallow groundwater within the Yaoquan volcanic area was also polluted by nitrate from human activities. Denitrification of shallow groundwater is slow, reducing the potential for "self-remediation". The concentration data are supported by nitrogen (N) isotope data; wells and springs exhibited N isotopic ratios between - 5‰ and + 5‰ (typical of fertilizers and precipitation) and exhibited higher oxygen (O) isotope values than water in the Wudalianchi lakes. These relationships suggest that nitrate in shallow mineral springs, wells, and lakes near the Yaoquan volcano was derived from the mixing of chemical fertilizers with local summer rainfall.