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Grain protein content (GPC) is a crucial quality trait in bread wheat, which is influenced by the key transcription factor TaNAM. However, the regulatory mechanisms of TaNAM have remained largely elusive. In this study, a new role of TaNAM was unveiled in regulating nitrogen remobilisation which impacts GPC. The TaNAM knockout mutants generated by clustered regularly interspaced short palindromic repeats/Cas9 exhibited significantly delayed senescence and lower GPC, while overexpression of TaNAM-6A resulted in premature senility and much higher GPC. Further analysis revealed that TaNAM directly activates the genes TaNRT1.1 and TaNPF5.5s, which are involved in nitrogen remobilisation. This activity aids in the transfer of nitrogen from leaves to grains for protein synthesis. In addition, an elite allele of TaNAM-6A, associated with high GPC, was identified as a candidate gene for breeding high-quality wheat. Overall, our work not only elucidates the potential mechanism of TaNAM-6A affecting bread wheat GPC, but also highlights the significance of nitrogen remobilisation from senescent leaves to grains for protein accumulation. Moreover, our research provides a new target and approach for improving the quality traits of wheat, particularly the GPC.
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Nitrogênio , Triticum , Triticum/genética , Triticum/metabolismo , Nitrogênio/metabolismo , Proteínas de Grãos/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Grão Comestível/metabolismo , Grão Comestível/genética , Folhas de Planta/metabolismo , Folhas de Planta/genéticaRESUMO
The chemistry of ozone (O3) on indoor surfaces leads to secondary pollution, aggravating the air quality in indoor environments. Here, we assess the heterogeneous chemistry of gaseous O3 with glass plates after being 1 month in two different kitchens where Chinese and Western styles of cooking were applied, respectively. The uptake coefficients of O3 on the authentic glass plates were measured in the dark and under UV light irradiation typical for indoor environments (320 nm < λ < 400 nm) at different relative humidities. The gas-phase product compounds formed upon reactions of O3 with the glass plates were evaluated in real time by a proton-transfer-reaction quadrupole-interface time-of-flight mass spectrometer. We observed typical aldehydes formed by the O3 reactions with the unsaturated fatty acid constituents of cooking oils. The formation of decanal, 6-methyl-5-hepten-2-one (6-MHO), and 4-oxopentanal (4-OPA) was also observed. The employed dynamic mass balance model shows that the estimated mixing ratios of hexanal, octanal, nonanal, decanal, undecanal, 6-MHO, and 4-OPA due to O3 chemistry with authentic grime-coated kitchen glass surfaces are higher in the kitchen where Chinese food was cooked compared to that where Western food was cooked. These results show that O3 chemistry on greasy glass surfaces leads to enhanced VOC levels in indoor environments.
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Poluição do Ar em Ambientes Fechados , Culinária , Vidro , Ozônio , Compostos Orgânicos Voláteis , Ozônio/química , Vidro/química , Poluentes AtmosféricosRESUMO
BACKGROUND: Paclitaxel (PTX) resistance has become a notable clinical concern of Non-small cell lung cancer (NSCLC). Our study aim is to investigate the effects of Resveratrol (RES) on NSCLC cells that have developed resistance to PTX. The NSCLC cell line A549 was employed in this investigation to establish a PTX-resistant NSCLC cell line, denoted as A549/PTX, and established tumor transplantaton model. The presence of miR-671-5p, Stomatin-like protein 2 (STOML2), and mitophagy biomarkers was evaluated using quantitative teal-time PCR (qRT-PCR) and western blot, The assessment of cell proliferation and apoptosis was conducted through the utilisation of colony formation and flow cytometry assays. The investigation of mitochondrial autolysosomes was conducted using transmission electron microscopy (TEM). Our results showed that the application of RES therapy resulted in a substantial improvement in the sansitivity of A549/PTX cells. RES exhibited an augmentation of apoptosis and a suppression of mitophagy in A549/PTX cells. RES induced an upregulation in the expression of miR-671-5p. This, in turn, leaded to the inhibition of STOML2, a protein that directly interacts with PINK1. In summary, our research indicates that RES improved the susceptibility of A549/PTX cells to PTX through miR-671-5p-mediated STOML2 inhibition.
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Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , MicroRNAs , Humanos , Paclitaxel/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , Células A549 , Resveratrol/farmacologia , MicroRNAs/genética , MicroRNAs/metabolismo , Resistencia a Medicamentos Antineoplásicos , Apoptose , Ubiquitina-Proteína Ligases/genética , Autofagia , Proteínas Quinases , Proliferação de Células , Linhagem Celular TumoralRESUMO
BACKGROUND: The informal caregivers of adult patients with ß-thalassemia major (ß-TM) bear not only physical but also emotional and economic pressures of providing care. This study is the first to evaluate the caregiver burden by Zarit Burden Interview (ZBI) of adult patients with ß-TM in mainland China and to identify predictors of caregiver burden. METHODS: In this cross-sectional study, we conducted an online survey with snowball sampling covering seven provinces between September 1, 2021, and January 31, 2022, of patients aged ≥ 18 years with ß-TM and their informal caregivers. Caregiver burden was assessed using the ZBI. Data on patient demographics, disease and therapy characteristics, and informal caregivers' demographic characteristics were collected and analysed using independent t-tests, analysis of variance, Spearman's correlation and multiple linear regression. RESULTS: Of 75 included patients, more than half (50.7%) were male. The mean patient age was 24.69 ± 5.59 years. The mean age of the informal caregivers was 50.60 ± 9.16 years, with women (74.7%) being predominant. The ZBI score was 38.00 ± 17.02. Multiple linear regression analysis showed that patients with interrupted blood transfusion therapy and informal caregivers required to care of others were positively associated with caregiver burden (p < 0.05). Age of informal caregivers were borderline significant positively associated with caregiver burden (p < 0.1). Married informal caregivers were negatively associated with caregiver burden (p < 0.05). CONCLUSIONS: The informal caregivers of adult patients with ß-TM in mainland China experienced a moderate-to-severe level of caregiving burden. The caregiver burden was higher in patients with a history of interrupted blood transfusion therapy or in informal caregivers who were older or needed to care for others. Additionally, married informal caregivers experienced lower burdens compared to non-married informal caregivers. These findings provide a reference to identify informal caregivers with higher burdens among patients with ß-TM.
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Decades of research have established the toxicity of soot particles resulting from incomplete combustion. However, the unique chemical compounds responsible for adverse health effects have remained uncertain. This study utilized mass spectrometry to analyze the chemical composition of extracted soot organics at three oxidation states, aiming to establish quantitative relationships between potentially toxic chemicals and their impact on human alveolar basal epithelial cells (A549) through metabolomics-based evaluations. Targeted analysis using MS/MS indicated that particles with a medium oxidation state contained the highest total abundance of compounds, particularly oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) composed of fused benzene rings and unsaturated carbonyls, which may cause oxidative stress, characterized by the upregulation of three specific metabolites. Further investigation focused on three specific OPAH standards: 1,4-naphthoquinone, 9-fluorenone, and anthranone. Pathway analysis indicated that exposure to these compounds affected transcriptional functions, the tricarboxylic acid cycle, cell proliferation, and the oxidative stress response. Biodiesel combustion emissions had higher concentrations of PAHs, OPAHs, and nitrogen-containing PAHs (NPAHs) compared with other fuels. Quinones and 9,10-anthraquinone were identified as the dominant compounds within the OPAH category. This knowledge enhances our understanding of the compounds contributing to adverse health effects observed in epidemiological studies and highlights the role of aerosol composition in toxicity.
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Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Compostos Policíclicos , Humanos , Compostos Policíclicos/análise , Fuligem/análise , Fuligem/química , Fuligem/toxicidade , Espectrometria de Massas em Tandem , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Pulmão , Oxigênio/análise , Metaboloma , Poluentes Atmosféricos/análise , Emissões de Veículos/análiseRESUMO
This study investigates seasonal variations of mass absorption efficiency of elemental carbon (MAEEC) and possible influencing factors in urban Guangzhou of South China. Mass concentrations of elemental carbon (EC) and organic carbon (OC) in PM2.5 and aerosol absorption coefficient (bap) at multi-wavelengths were simultaneously measured in four seasons of 2018-2019 at hourly resolution by a semi-continuous carbon analyzer and an aethalometer. Seasonal average mass concentrations of EC were in the range of 1.36-1.70 µgC/m3 with a lower value in summer than in the other seasons, while those of OC were in the range of 4.70-6.49 µgC/m3 with the lowest value in summer and the highest in autumn. Vehicle exhaust from local traffic was identified to be the predominant source of carbonaceous aerosols. The average aerosol absorption Ångström exponents (AAE) were lower than 1.2 in four seasons, indicating EC and bap were closely related with vehicle exhaust. Seasonal MAEEC at 550 nm was 11.0, 8.5, 10.4 and 11.3 m2/g in spring, summer, autumn, and winter, respectively. High MAEEC was related with the high mass ratio of non-carbonaceous aerosols to EC and high ambient relative humidity.
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Poluentes Atmosféricos , Material Particulado , Material Particulado/análise , Poluentes Atmosféricos/análise , Estações do Ano , Monitoramento Ambiental , China , Emissões de Veículos , Carbono/análise , Aerossóis/análiseRESUMO
Heat stress substantially reduces the yield potential of wheat (Triticum aestivum L.), one of the most widely cultivated staple crops, and greatly threatens global food security in the context of global warming. However, few studies have explored the heat stress tolerance (HST)-related genetic resources in wheat. Here, we identified and fine-mapped a wheat HST locus, TaHST2, which is indispensable for HST in both the vegetative and reproductive stages of the wheat life cycle. The studied pair of near isogenic lines (NILs) exhibited diverse morphologies under heat stress, based on which we mapped TaHST2 to a 485 kb interval on chromosome arm 4DS. Under heat stress, TaHST2 confers a superior conversion rate from soluble sugars to starch in wheat grains, resulting in faster grain filling and a higher yield potential. A further exploration of genetic resources indicated that TaHST2 underwent strong artificial selection during wheat domestication, suggesting it is an essential locus for basal HST in wheat. Our findings provide deeper insights into the genetic basis of wheat HST and might be useful for global efforts to breed heat-stress-tolerant cultivars.
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Termotolerância , Triticum , Triticum/genética , Melhoramento Vegetal , Resposta ao Choque Térmico/genética , Termotolerância/genética , Grão Comestível/genéticaRESUMO
KEY MESSAGE: QHd.cau-7D.1 for heading date was delimited into the physical interval of approximately 17.38 Mb harboring three CONSTANS-like zinc finger genes. Spike morphological traits, plant height and heading date play important roles in yield improvement of wheat. To reveal the genetic factors that controlling spike morphological traits, plant height and heading date on the D genome, we conducted analysis of quantitative traits locus (QTL) using 198 F7:8 recombinant inbred lines (RILs) derived from a cross between the common wheat TAA10 and resynthesized allohexaploid wheat XX329 with similar AABB genomes. A total of 23 environmentally stable QTL on the D sub-genome for spike length (SL), fertile spikelet number per spike (FSN), sterile spikelet number per spike (SSN), total spikelet number per spike (TSN), spike compactness (SC), plant height (PHT) and heading date (HD) were detected, among which eight appeared to be novel QTL. Furthermore, QHd.cau-7D.1 and QPht.cau-7D.2 shared identical confidence interval and were delimited into the physical interval of approximately 17.38 Mb with 145 annotated genes, including three CONSTANS-like zinc finger genes (TraesCS7D02G209000, TraesCS7D02G213000 and TraesCS7D02G220300). This study will help elucidate the molecular mechanism of the seven traits (SL, FSN, SSN, TSN, SC, PHT and HD) and provide a potentially valuable resource for genetic improvement.
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Locos de Características Quantitativas , Triticum , Ligação Genética , Fenótipo , Triticum/genéticaRESUMO
KEY MESSAGE: We identified genomic regions associated with six quality-related traits in wheat under two sowing conditions and analyzed the effects of multienvironment-significant SNPs on the stability of these traits. Grain quality affects the nutritional and commercial value of wheat (Triticum aestivum L.) and is a critical factor influencing consumer preferences for specific wheat varieties. Climate change is predicted to increase environmental stress and thereby reduce wheat quality. Here, we performed a genotyping assay involving the use of the wheat 90 K array in a genome-wide association study of six quality-related traits in 486 wheat accessions under two sowing conditions (normal and late sowing) over 4 years. We identified 64 stable quantitative trait loci (QTL), including 10 for grain protein content, 9 for wet gluten content, 4 for grain starch content, 14 for water absorption, 15 for dough stability time and 12 for grain hardness in wheat under two sowing conditions. These QTL harbored 175 single nucleotide polymorphisms (SNPs), explaining approximately 3-13% of the phenotypic variation in multiple environments. Some QTL on chromosomes 6A and 5D were associated with multiple traits simultaneously, and two (QNGPC.cau-6A, QNGH.cau-5D) harbored known genes, such as NAM-A1 for grain protein content and Pinb for grain hardness, whereas other QTL could facilitate gene discovery. Forty-three SNPs that were detected under late or both normal and late sowing conditions appear to be related to phenotypic stability. The effects of these SNP alleles were confirmed in the association population. The results of this study will be useful for further dissecting the genetic basis of quality-related traits in wheat and developing new wheat cultivars with desirable alleles to improve the stability of grain quality.
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Locos de Características Quantitativas , Sementes/química , Triticum/genética , Alelos , Grão Comestível/genética , Estudos de Associação Genética , Genótipo , Glutens , Fenótipo , Polimorfismo de Nucleotídeo Único , Amido , Tempo (Meteorologia)RESUMO
Nitrous acid (HONO) is an important photochemical precursor to hydroxyl radicals particularly in an urban atmosphere, yet its primary emission and secondary production are often poorly constrained. Here, we measured HONO and nitrogen oxides (NOx) at both the inlet and the outlet in a busy urban tunnel (>30â¯000 vehicles per day) in south China. Multiple linear regression revealed that 73.9% of the inlet-outlet incremental HONO concentration was explained by NO2 surface conversion, while the rest was directly emitted from vehicles with an average HONO/NOx ratio of 1.31 ± 0.87%, which was higher than that from previous tunnel studies. The uptake coefficient of NO2, γ(NO2), on the tunnel surfaces was calculated to be (7.01 ± 0.02) × 10-5, much higher than that widely used in models. As tunnel surfaces are typical of urban surfaces in the wall and road materials, the dominance of HONO from surface reactions in the poorly lit urban tunnel demonstrated the importance of NO2 conversion on urban surfaces, instead of NO2 conversion on the aerosol surface, for both daytime and night-time HONO even in polluted ambient air. The higher γ(NO2) on urban surfaces and the elevated HONO/NOx ratio from this study can help explain the missing HONO sources in urban areas.
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Ácido Nitroso , Emissões de Veículos , Aerossóis , Atmosfera , Dióxido de NitrogênioRESUMO
Starch and prolamin composition and content are important indexes for determining the processing and nutritional quality of wheat (Triticum aestivum L.) grains. Several transcription factors (TFs) regulate gene expression during starch and protein biosynthesis in wheat. Storage protein activator (TaSPA), a member of the basic leucine zipper (bZIP) family, has been reported to activate glutenin genes and is correlated to starch synthesis related genes. In this study, we generated TaSPA-B overexpressing (OE) transgenic wheat lines. Compared with wild-type (WT) plants, the starch content was slightly reduced and starch granules exhibited a more polarized distribution in the TaSPA-B OE lines. Moreover, glutenin and ω- gliadin contents were significantly reduced, with lower expression levels of related genes (e.g., By15, Dx2, and ω-1,2 gliadin gene). RNA-seq analysis identified 2023 differentially expressed genes (DEGs). The low expression of some DEGs (e.g., SUSase, ADPase, Pho1, Waxy, SBE, SSI, and SS II a) might explain the reduction of starch contents. Some TFs involved in glutenin and starch synthesis might be regulated by TaSPA-B, for example, TaPBF was reduced in TaSPA-B OE-3 lines. In addition, dual-luciferase reporter assay indicated that both TaSPA-B and TaPBF could transactivate the promoter of ω-1,2 gliadin gene. These results suggest that TaSPA-B regulates a complex gene network and plays an important role in starch and protein biosynthesis in wheat.
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Grão Comestível/genética , Grão Comestível/metabolismo , Expressão Gênica , Proteínas de Plantas/genética , Amido/metabolismo , Triticum/genética , Grão Comestível/química , Perfilação da Expressão Gênica , Ontologia Genética , Anotação de Sequência Molecular , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Sementes/metabolismo , Sementes/ultraestrutura , Amido/ultraestrutura , Triticum/química , Triticum/metabolismoRESUMO
The purpose of this study was to explore the enhancing effects and the mechanism of monocyclic monoterpene penetration enhancers (menthol and menthone) on the transdermal absorption of ligustrazine hydrochloride (LH). Franz-type diffusion cells were used to determine percutaneous parameters of LH in vitro and surface changes of porcine skin were studied by a scanning electron microscope (SEM). The effects of promoters on the biophysical natures of stratum corneum (SC) were researched by Fourier transform-infrared (FT-IR). Penetration parameters of menthol (p < 0.01) and menthone groups (p < 0.05) were greater than those of the control; morphological changes of skin monitored by SEM demonstrated that the menthone group had the most disruption and desquamation of SC flakes, which resulted from extracted lipids. FT-IR measurements showed menthone had the greatest changes in peak shift and peak area, which resulted from C-H stretching vibrations of SC lipids. The results suggest that the penetration mechanism might include disturbing and extracting SC lipids and the hydrogen bond connection.
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Portadores de Fármacos/química , Monoterpenos/química , Pirazinas/administração & dosagem , Absorção Cutânea , Pele/metabolismo , Vasodilatadores/administração & dosagem , Administração Cutânea , Animais , Pirazinas/farmacocinética , Pele/ultraestrutura , Suínos , Vasodilatadores/farmacocinéticaRESUMO
The aim of this study was to determine the raising anticancer effects of resveratrol (Res) on paclitaxel (PA) in non-small cell lung cancer (NSCLC) cell line A549. The 10 µg/ml of Res had no effect on human fetal lung fibroblast MRC-5 cells or on A549 cancer cells and the 5 or 10 µg/ml of PA also had no effect on MRC-5 normal cells. PA-L (5 µg/ml) and PA-H (10 µg/ml) had the growth inhibitory effects in NSCLC cell line A549, and Res increased these growth inhibitory effects. By flow cytometry experiment, after Res (5 µg/ml)+PA-H (10 µg/ml) treatment, the A549 cells showed the most apoptosic cells compared to other group treatments, and after additional treatment with Res, the apoptosic cells of both two PA concentrations were raised. Res+PA could reduce the mRNA and protein expressions of COX-2, and Res+PA could reduce the COX-2 related genes of VEGF, MMP-1, MMP-2, MMP-9, NF-κB, Bcl-2, Bcl-xL, procollagen I, collagen I, collagen III and CTGF, TNF-α, IL-1ß, iNOS and raise the TIMP-1, TIMP-2, TIMP-3, IκB-α, p53, p21, caspase-3, caspase-8, caspase-9, Bax genes compared to the control cells and the PA treated cells. From these results, it can be suggested that Res could raise the anticancer effects of PA in A549 cells, thus Res might be used as a good sensitizing agent for PA.
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Daphne genkwa Sieb.et Zucc. is a well-known medicinal plant. This study was designed to investigate the anticancer effects of total flavonoids in D. genkwa (TFDG) in vitro and in vivo. HT-29 and SW-480 human colorectal cancer cells were cultured to investigate the anticancer activity of TFDG. In addition, the Apc(Min/+) mouse model was applied in the in vivo experiment. Results of the cell experiment revealed that TFDG possessed significant inhibitory effects on HT-29 and SW-480 human colorectal cancer cells (both p < 0.01). Furthermore, our in vivo data showed that after treatment with TFDG, there was a significant increase in life span (both p < 0.01) and tumor numbers were reduced in the colon (both p < 0.01), which was supported by the data of tumor distribution, body weight changes and organ index. Our results also indicated that expressions of interleukin (IL)-1α, IL-1ß, IL-6, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor in gut tissue were downregulated by treatments of TFDG, and immunity cytokine secretions in the serum were regulated after oral administration of TFDG. Taken together, these findings suggested that TFDG has a potential clinical utility in colorectal cancer therapeutics, and TFDG's action is likely linked to its ability to regulate immune function and inhibit the production of inflammatory cytokines.
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Neoplasias Colorretais/tratamento farmacológico , Daphne/química , Flavonoides/farmacologia , Extratos Vegetais/farmacologia , Animais , Linhagem Celular Tumoral/efeitos dos fármacos , Colo/patologia , Citocinas/metabolismo , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plantas Medicinais/químicaRESUMO
In the quest for durable photovoltaic devices, 2D halide perovskites have emerged as a focus of extensive research. However, the reduced dimension in structure is accompanied by inferior optical-electrical properties, such as widened band gap, enhanced exciton binding energy, and obstructed charge transport. As a result, the efficiency of 2D perovskite solar cells (PSCs) lags significantly behind their 3D counterparts. To overcome these constraints, extensive investigations into materials and processing techniques are pursued rigorously to augment the efficiency of 2D PSCs. Herein, The cutting-edge delve into developments in 2D PSCs, with a focus on chemical and material engineering, as well as their structure and photovoltaic properties. The review starts with an introduction of the crystal structure, followed by the key evaluation criteria of 2D PSCs. Then, the strategies around solution chemical engineering, processing technique, and interface optimization, to simultaneously boost efficiency and stability are systematically discussed. Finally, the challenges and perspectives associated with 2D perovskites to provide insights into potential improvements in photovoltaic performance will be outlined.
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Grain albumin is highly nutritious and closely related to the processing quality of wheat. However, few studies have explored the grain albumin content (GAC) in wheat. This study aims to uncover quantitative trait loci (QTLs) linked to wheat GAC by analyzing a doubled haploid (DH) population derived from common wheat cultivars ShanNong23 and ZhouMai17. We detected six QTLs controlling GAC on chromosomes 1B, 5A, and 6D, with individual QTL explaining 5.78% to 22.29% of the GAC variation. The effect of QGac.cau-1B.1 on GAC is attributed to the presence of the 1BL/1RS translocation, indicating that the 1BL/1RS translocation increase of GAC compared with the non-1BL/1RS translocation lines. The higher GAC observed in 1BL/1RS lines could be primarily attributed to the increased accumulation of omega-secalin, omega-gliadin, low molecular weight glutenin subunit and ribosomal protein content. Additionally, we also found that the SDS-sedimentation value of whole wheat flour was decreased by adding albumin solution. These results advance our understanding of the genetic basis of GAC and offer novel perspectives for enhancing wheat quality through genetic enhancements.
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Compared with layered materials such as graphite and transition metal disulfide compounds with highly anisotropic in-plane covalent bonds, it is inherently more challenging to obtain independent metallic two-dimensional films with atomic thickness. In this study, PtNi layered metallene nanobowls (LMBs) with multilayer atomic-scale nanosheets and bowl-like structures have been synthesized in one step using structural and electronic effects. The material has the advantage of catalyzing pH-universal hydrogen evolution reaction (HER). Compared with Pt/C, PtNi LMBs exhibited excellent HER activity and stability under all pH conditions. The overpotentials of 10 mA cm-2 at 0.5 M H2SO4, 1.0 M phosphate buffer and 1.0 M KOH were 14.8, 20.3, and 34.0 mV, respectively. Under acidic, neutral and alkaline conditions, the HER Faraday efficiencies reach 98.97%, 98.85%, and 99.04%, respectively. This study provides an example for the preparation of unique multilayer nanobowls, and also provides a basic research platform for the development of special HER materials.
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Cyanobacteria are ever-present, mainly flourishing in aquatic environments and surviving virtually in other habitats. The microbiota of indoor dust on the pre-filter of heating, ventilation, and air-conditioning (HVAC) systems, which reflect indoor microbial contamination and affect human health, has attracted attention. Contemporary studies on cyanobacteria deposited on the pre-filter of HVAC remain scant. By the culture-independent approach of qPCR and high throughput sequencing technologies, our results documented that the cyanobacterial concentrations were highest in autumn, occurred recurrently, and were about 2.60 and 10.57-fold higher than those in winter and summer. We proposed that aquatic and terrestrial cyanobacteria contributed to the pre-filter of HVAC by airborne transportation produced by wave breaks, bubble bursts, and soil surface by wind force, owing to the evidence that cyanobacteria were commonly detected in airborne particulate matters. The cyanobacteria community structure was characterized in Shanghai, where Chroococcidiopsaceae, norank_cyanobacteriales, Nostocaceae, Paraspirulinaceae, and others dominated the dust on the pre-filter of HVAC. Some detected genera, including Nodularia sp., Pseudanabaena sp., and Leptolyngbya sp., potentially produced cyanobacterial toxins, which need further studying to determine their potential threat to human health. The present work shed new insight into cyanobacteria distribution in the specific environment besides aquatic habitats.
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Nitrated aromatic compounds (NACs) are important components of brown carbon (BrC), and their health and climate effects are of wide concern. Biomass burning is a major contributor to NACs in the atmosphere, yet NACs emitted from biomass burning are poorly constrained. In this study particulate NACs from open burning of corn straws were characterized in terms of their compositions, light absorption and toxic equivalents. 1, 6-dinitropyrene was the most abundant species among the measured nitropolycyclic aromatic hydrocarbons (NPAHs) with a share of 13.4% in total NPAHs, while 4-nitrocatechol was the most abundant nitrophenol (NP) species and accounted for 25.4% of measured NPs. 2-nitropyrene, widely used as a marker of secondary formation of NPAHs, was found to be the second most abundant NPAHs (13.3% of the total NPAHs) in the particulate matter (PM) primarily emitted from corn straw burning, and thus is inappropriate to be an indicator of the secondary formation. The measured primary NACs could only explain a negligible part (0.2%) of the light absorption by BrC. Although the concentrations of 9 toxic NACs were less than one-third of the 16 USEPA priority PAHs, their benzo(a)pyrene toxic equivalency quotients however were approximately 10 times that of the 16 PAHs. This study suggests that in comparison of PAHs from straw burning, NACs should be given greater attention due to their potentially higher toxic effects.
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Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Atmosféricos/análise , Nitrocompostos , Zea mays , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Poeira , Carvão Mineral/análise , Monitoramento Ambiental , ChinaRESUMO
It is known that the transformation of Fe and S forms in soil affects the migration and activity of Cd, but the coordinated regulation of Cd activity by Fe and S under different redox conditions is still unclear. Here, Diffusive gradients in thin films (DGT), an in-situ monitoring technique, is used to explore the difference of the regulation of Cd activity in paddy fields with ferrihydrite (FH) and ferrihydrite coprecipitated by sulfate (FH-S) under the flooding and drainage conditions. The addition of FH-S and FH significantly reduced the activity of Cd (Dissolved, Exchanged, and CDGT-Cd). Compared with pure FH, the adsorption extent of Cd in FH was enhanced by increasing concentrations of SO42- (i.e., S/Fe ratio), which is attributed to the decrease in the crystallinity of FH by sulfate. During soil flooding, the addition of FH-S promoted the production of metal sulfide (CdS and FeS/FeS2). The activity of Cd increased after drainage, while the FH-S treatment groups delayed the release of Cd. After 30 days of drainage, the concentration of Cd in FH-S treatment groups decreased by 28.9-44.1 % compared with the control group. The fresh FeS/FeS2 is not the main adsorbent for fixing Cd, and due to the existence of oxidation compensation mechanism, the preferential oxidation of FeS/FeS2 delays the release of Cd in the drainage stage. Our study shed new light on the mechanism of Fe-S synergistic regulation of Cd and remediation of Cd-contaminated soils.