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1.
Biomed Pharmacother ; 129: 110375, 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32540645

RESUMO

Endoplasmic reticulum stress (ERS), mutual crosstalk between autophagy and apoptosis-related signaling pathway, plays an important role in the process of acute liver injury (ALI). The present study was to investigate the effects and underlying mechanisms of Asiatic acid from Potentilla chinensis (AAPC) on ALI. The model of ALI in mice was induced by administration with Lipopolysaccharide/D-Galactosamine (LPS/D-GalN). The effects of AAPC on hepatic pathology and hepatocyte apoptosis were observed by hematoxylin-eosin (H&E) staining and TUNEL staining. Serum transaminases activities were measured using an automated biochemical analyzer. Moreover, ERS and autophagy were induced in LO2 cells, respectively. Cell cycle and apoptosis were analyzed using flow cytometry. In addition, ERS and autophagy-related pathways were detected in vivo and in vitro. The results showed that AAPC significantly ameliorated LPS/D-GalN-induced ALI in mice, as evidenced by the improvement of liver pathology and the decrease in serum alanine aminotransferase (ALT) and aspartate transaminase (AST) activities. Moreover, AAPC pre-treatment markedly inhibited thapsigargin-induced cell apoptosis, accompanied by cell cycle arrest at S/G1 phase in LO2 cells. AAPC notably inhibited the activation of the PERK/ATF6 and IRE1 pathway, alleviating the extent of ERS. Additionally, AAPC significantly promoted autophagy, as evidenced by the increase in the formation of autophagic vacuoles and the number of autophagosomes as well as the increased expressions of LC3II/I, Beclin-1, Atg5 and Atg7. In summary, our results indicate that AAPC significantly ameliorates ALI by inhibiting the ERS pathway and promoting hepatocyte autophagy.

2.
Cell Biochem Funct ; 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32564421

RESUMO

The present study was to investigate the inhibitory effect and underlying mechanism of Tormentic acid (TA) on hepatic stellate cells (HSCs). HSC-T6 cells were stimulated with Platelet-derived growth factor-BB (PDGF-BB) and TA, and then cell proliferation, apoptosis, inflammatory factor, and collagen-related indicators were detected. In order to elucidate the potential mechanism, the PI3K/Akt/mTOR and NF-κB signalling pathways were also detected. The results showed that TA treatment markedly inhibited PDGF-BB-stimulated HSC-T6 cell activation, as evidenced by the inhibition of cell proliferation, migration and colony formation, as well as the decreased expression of TGF-ß and α-SMA. TA treatment caused a significant increase in the activity of lactate dehydrogenase and significantly promoted cell apoptosis. TA treatment significantly reduced aspartate aminotransferase, alanine aminotransferase and total bilirubin activity. Importantly, TA inhibited the expression of collagen type I and III, alleviating the excessive deposition of extracellular matrix (ECM). Further experiments showed that TA administration significantly inhibited the phosphorylation of PI3K, Akt, FAK and mTOR and the protein expression of P70S6K, indicating the inhibition of the PI3K/Akt/mTOR pathway. Moreover, treatment with TA markedly decreased the phosphorylation of IκBα, NF-κB p65 and IKKα/ß, thereby blocking the NF-κB signal transduction. In summary, this study demonstrates that TA significantly inhibits HSC activation and promotes cell apoptosis via the inhibition of the PI3K/Akt/mTOR and NF-κB signalling pathways. SIGNIFICANCE OF THE STUDY: Tormentic acid (TA) could inhibit HSC activation and alleviate collagen-based ECM deposition, suggesting that TA exerted anti-hepatic fibrosis. Further mechanism research revealed that the inhibition of TA on HSC activation might be through blocking the PI3K/Akt/mTOR and NF-κB signalling pathways. These findings provided a new cue to understand the protective effect of TA against liver fibrosis, which may provide a potential nature medicine for the treatment of liver fibrosis.

3.
Artigo em Inglês | MEDLINE | ID: mdl-32414793

RESUMO

Geothermal systems emit substantial amounts of aqueous, gaseous and methylated mercury, but little is known about microbial influences on mercury speciation. Here we report results from genome-resolved metagenomics and mercury speciation analysis of acid warm springs in the Ngawha Geothermal Field (<55 °C, pH < 4.5), Northland Region, Aotearoa New Zealand. Our aim was to identify the microorganisms genetically equipped for mercury methylation, demethylation, or Hg(II) reduction to volatile Hg(0) in these springs. Dissolved total and methylated mercury concentrations in two adjacent springs with different mercury speciation ranked among the highest reported from natural sources (250-16000 ng L-1 and 0.5-13.9 ng L-1, respectively). Total solid mercury concentrations in spring sediments ranged from 1273 to 7000 µg g-1 In the context of such ultra-high mercury levels, the geothermal microbiome was unexpectedly diverse, and dominated by acidophilic and mesophilic sulfur- and iron-cycling bacteria, mercury- and arsenic-resistant bacteria, and thermophilic and acidophilic archaea. Integrating microbiome structure and metagenomic potential with geochemical constraints, we constructed a conceptual model for biogeochemical mercury cycling in geothermal springs. The model includes abiotic and biotic controls on mercury speciation, and illustrates how geothermal mercury cycling may couple to microbial community dynamics and sulfur and iron biogeochemistry.IMPORTANCE Little is currently known about biogeochemical mercury cycling in geothermal systems. This manuscript presents a new conceptual model, supported by genome-resolved metagenomic analysis and detailed geochemical measurements. The model illustrates environmental factors that influence mercury cycling in acidic springs, including transitions between solid (mineral) and aqueous phases of mercury, as well as the interconnections among mercury, sulfur and iron cycles. This work provides a framework for studying natural geothermal mercury emissions globally. Specifically, our findings have implications for mercury speciation in wastewaters from geothermal power plants and the potential environmental impacts of microbially and abiotically formed mercury species, particularly where mobilized in spring waters that mix with surface- or ground-waters. Furthermore, in the context of thermophilic origins for microbial mercury volatilization, this report yields new insights into how such processes may have evolved alongside microbial mercury methylation/demethylation, and the environmental constraints imposed by the geochemistry and mineralogy of geothermal systems.

4.
Opt Lett ; 45(10): 2688-2691, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32412442

RESUMO

The diffractive deep neural network (D2NN) has demonstrated its importance in performing various all-optical machine learning tasks, e.g., classification, segmentation, etc. However, deeper D2NNs that provide higher inference complexity are more difficult to train due to the problem of gradient vanishing. We introduce the residual D2NNs (Res-D2NN), which enables us to train substantially deeper diffractive networks by constructing diffractive residual learning blocks to learn the residual mapping functions. Unlike the existing plain D2NNs, Res-D2NNs contribute to the design of a learnable light shortcut to directly connect the input and output between optical layers. Such a shortcut offers a direct path for gradient backpropagation in training, which is an effective way to alleviate the gradient vanishing issue on very deep diffractive neural networks. Experimental results on image classification and pixel super-resolution demonstrate the superiority of Res-D2NNs over the existing plain D2NN architectures.

5.
Artigo em Inglês | MEDLINE | ID: mdl-32421230

RESUMO

This article offers a materials-chemistry perspective for colloidal quantum dots (QDs) in the field of display, including QD-enhanced liquid-crystal-display (QD-LCD) and QD-based light-emitting-diodes (QLEDs) display. The rapid successes of QDs for display in the past five years are not accidental but have a deep root in both maturity of their synthetic chemistry and their unique chemical, optical, and optoelectronic properties. This article intends to discuss the natural match of QD emitters for display and chemical means to eventually bring about their full potential.

6.
Nat Commun ; 11(1): 2309, 2020 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-32385262

RESUMO

Electroluminescence of colloidal nanocrystals promises a new generation of high-performance and solution-processable light-emitting diodes. The operation of nanocrystal-based light-emitting diodes relies on the radiative recombination of electrically generated excitons. However, a fundamental question-how excitons are electrically generated in individual nanocrystals-remains unanswered. Here, we reveal a nanoscopic mechanism of sequential electron-hole injection for exciton generation in nanocrystal-based electroluminescent devices. To decipher the corresponding elementary processes, we develop electrically-pumped single-nanocrystal spectroscopy. While hole injection into neutral quantum dots is generally considered to be inefficient, we find that the intermediate negatively charged state of quantum dots triggers confinement-enhanced Coulomb interactions, which simultaneously accelerate hole injection and hinder excessive electron injection. In-situ/operando spectroscopy on state-of-the-art quantum-dot light-emitting diodes demonstrates that exciton generation at the ensemble level is consistent with the charge-confinement-enhanced sequential electron-hole injection mechanism probed at the single-nanocrystal level. Our findings provide a universal mechanism for enhancing charge balance in nanocrystal-based electroluminescent devices.

7.
Chem Commun (Camb) ; 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32391823

RESUMO

Herein, the coordination-induced increase in the electron density of fused C6 rings in MOFs as high performance anode materials for Li+ ion batteries is described. Zn-PTCA is able to deliver a high specific capacity of 700 mA h g-1 at 50 mA g-1 and exhibits excellent cycle performance over 1100 cycles and good rate capability.

8.
Int Immunopharmacol ; 83: 106445, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32272395

RESUMO

The purpose of this study was to synthesize 4-hydroxybenzo[d]oxazol-2(3H)-one (HBO) and to investigate its protective effects on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury. HBO (C7H5O3N) was synthesized based on 2-nitro-resorcinol and identified by physicochemical analysis. In the animal experiment, mice were pretreated with HBO (50, 100, 200 mg/kg) for 10 days. At the end of pretreatment, the animals were injected with LPS (10 µg/kg)/D-GalN (700 mg/kg). The results showed that HBO significantly alleviated liver injury induced by LPS/D-GalN in mice. It remarkably decreased inflammatory response by reducing the levels of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). Moreover, HBO notably attenuated hepatocyte apoptosis by inhibiting the release of Cytochrome C (Cyt C) from mitochondria into the cytoplasm and regulating the expression of B-cell lymphoma-2 (Bcl-2) family. Furthermore, the result showed that HBO inhibited the expressions of nuclear factor kappa-B p50 (NF-κBp50), toll-like receptor 4 (TLR4), and myeloid differentiation factor 88 (MyD88), as well as the phosphorylation of inhibitor of nuclear factor kappa-B (IκB), inhibitor of nuclear factor kappa-B kinase-α/ß (IKK-α/ß), nuclear factor kappa-B p65 (NF-κBp65), suggesting that HBO had a certain influence on the TLR4/NF-κB pathway. In addition, the mitogen-activated protein kinase (MAPK) signaling pathway was also affected by HBO, as evidenced by the decrease in the phosphorylation levels of extracellular regulated protein kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38). In conclusion, our study suggested that HBO could protect against LPS/D-GalN-induced liver injury, moreover, treatment with HBO appeared to be capable of further regulating the TLR4/NF-κB and MAPK signaling pathways.

9.
Genome Res ; 30(3): 315-333, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32188701

RESUMO

Genomes are an integral component of the biological information about an organism; thus, the more complete the genome, the more informative it is. Historically, bacterial and archaeal genomes were reconstructed from pure (monoclonal) cultures, and the first reported sequences were manually curated to completion. However, the bottleneck imposed by the requirement for isolates precluded genomic insights for the vast majority of microbial life. Shotgun sequencing of microbial communities, referred to initially as community genomics and subsequently as genome-resolved metagenomics, can circumvent this limitation by obtaining metagenome-assembled genomes (MAGs); but gaps, local assembly errors, chimeras, and contamination by fragments from other genomes limit the value of these genomes. Here, we discuss genome curation to improve and, in some cases, achieve complete (circularized, no gaps) MAGs (CMAGs). To date, few CMAGs have been generated, although notably some are from very complex systems such as soil and sediment. Through analysis of about 7000 published complete bacterial isolate genomes, we verify the value of cumulative GC skew in combination with other metrics to establish bacterial genome sequence accuracy. The analysis of cumulative GC skew identified potential misassemblies in some reference genomes of isolated bacteria and the repeat sequences that likely gave rise to them. We discuss methods that could be implemented in bioinformatic approaches for curation to ensure that metabolic and evolutionary analyses can be based on very high-quality genomes.

10.
Curr Med Sci ; 40(2): 285-289, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32219626

RESUMO

Based on the New Diagnosis and Treatment Scheme for Novel Coronavirus Infected Pneumonia (Trial Edition 5), combined with our current clinical treatment experience, we recently proposed a revision of the first edition of "Guidance for maternal and fetal management during pneumonia epidemics of novel coronavirus infection in the Wuhan Tongji Hospital". This article focused on the issues of greatest concern of pregnant women including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection diagnostic criteria, inspection precautions, drug treatment options, indications and methods of termination of pregnancy, postpartum fever, breastfeeding considerations, mode of mother-to-child transmission, neonatal isolation and advice on neonatal nursing, to provide valuable experience for better management of SARS-CoV-2 infection in pregnant women and newborns.


Assuntos
Betacoronavirus , Infecções por Coronavirus/complicações , Pneumonia Viral/complicações , Complicações Infecciosas na Gravidez , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/prevenção & controle , Infecções por Coronavirus/terapia , Feminino , Humanos , Recém-Nascido , Transmissão Vertical de Doença Infecciosa , Pandemias/prevenção & controle , Isolamento de Pacientes , Pneumonia Viral/diagnóstico , Pneumonia Viral/prevenção & controle , Pneumonia Viral/terapia , Gravidez , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/terapia
12.
Nature ; 578(7795): 425-431, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32051592

RESUMO

Bacteriophages typically have small genomes1 and depend on their bacterial hosts for replication2. Here we sequenced DNA from diverse ecosystems and found hundreds of phage genomes with lengths of more than 200 kilobases (kb), including a genome of 735 kb, which is-to our knowledge-the largest phage genome to be described to date. Thirty-five genomes were manually curated to completion (circular and no gaps). Expanded genetic repertoires include diverse and previously undescribed CRISPR-Cas systems, transfer RNAs (tRNAs), tRNA synthetases, tRNA-modification enzymes, translation-initiation and elongation factors, and ribosomal proteins. The CRISPR-Cas systems of phages have the capacity to silence host transcription factors and translational genes, potentially as part of a larger interaction network that intercepts translation to redirect biosynthesis to phage-encoded functions. In addition, some phages may repurpose bacterial CRISPR-Cas systems to eliminate competing phages. We phylogenetically define the major clades of huge phages from human and other animal microbiomes, as well as from oceans, lakes, sediments, soils and the built environment. We conclude that the large gene inventories of huge phages reflect a conserved biological strategy, and that the phages are distributed across a broad bacterial host range and across Earth's ecosystems.


Assuntos
Bactérias/virologia , Bacteriófagos/classificação , Bacteriófagos/genética , Planeta Terra , Ecossistema , Genoma Viral/genética , Filogenia , Aminoacil-tRNA Sintetases/genética , Animais , Bactérias/genética , Bacteriófagos/isolamento & purificação , Bacteriófagos/metabolismo , Biodiversidade , Sistemas CRISPR-Cas/genética , Evolução Molecular , Regulação Bacteriana da Expressão Gênica , Regulação Viral da Expressão Gênica , Especificidade de Hospedeiro , Humanos , Lagos/virologia , Anotação de Sequência Molecular , Oceanos e Mares , Prófagos/genética , Biossíntese de Proteínas , RNA de Transferência/genética , Proteínas Ribossômicas/genética , Água do Mar/virologia , Microbiologia do Solo , Transcrição Genética
13.
Curr Neuropharmacol ; 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31989901

RESUMO

Although over 25 antiepileptic drugs (AEDs) have become currently available for clinical use, the incidence of epilepsy worldwide and the proportions of drug-resistant epilepsy among them are not significantly reduced during the past decades. Traditional screens for AEDs have been mainly focused on their anti-ictogenic roles, and their efficacies primarily depend on suppressing neuronal excitability or enhancing inhibitory neuronal activity, almost without the influence on the epileptogenesis or with inconsistent results from different studies. Epileptogenesis refers to the pathological process of a brain from its normal status to the alterations with the continuous prone of unprovoked spontaneous seizures after brain insults, such as stroke, traumatic brain injury, CNS infectious and autoimmune disorders, and even some specific inherited conditions. Recently growing experimental and clinical studies have discovered the underlying mechanisms for epileptogenesis, which are multiaspect and multistep. These findings provide us a number of interesting sites for antiepileptogenic drugs (AEGDs). AEGDs have been evidenced as significantly roles of postponing or completely blocking the development of epilepsy in experimental models. The present review will introduce potential novel candidate drug-targets for AEGDs based on the published studies.

14.
Neurosci Lett ; 723: 134774, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31981720

RESUMO

BACKGROUND: Brain function relies on the capacity of neurons to locally modulate each other at the level of synapses. Therefore, the exosomal pathway may constitute a well-designed mechanism for local and systemic interneuronal transfer of information within functional brain networks. Exosomes bind to and are endocytosed by neurons of different brain regions to play a definite role. The medial prefrontal cortex (mPFC) and nucleus accumbens (NAc) brain regions are known to involve in pain modulation. Our study observes the roles of exosomal activity in these two dominant regions of the pain-related pathway, and there influence on the analgesic effects in CCI mice. METHODS: We induced pain exosomes in the mPFC and NAc in the mice of chronic constriction injury of the sciatic nerve model to produce neuropathic pain, and assessed changes that might affect analgesic behaviors. These changes were measured through a combination of behavioral, surgical, and other cellular testings. RESULTS: Our study found that pain expression was elevated in mice given exogenous exosomes isolated from CCI mice, especially at the 2 h and 4 h time interval, in mice given exosomes at the mPFC and NAc, respectively. We also found that inhibiting formation of pain exosomes through GW4869 within the mPFC and NAc can elevate the pain threshold. CONCLUSION: Results from our study supported the idea that the release of mPFC and NAc exosomes of CCI model has elevated the pain sensations in the subjected mice. This study will further help in designing new clinical trials, and will revolutionize the drug-induced anesthetic responses.

15.
Artif Cells Nanomed Biotechnol ; 48(1): 137-142, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31852310

RESUMO

Our previous study found that IL33 repressed the growth of pulmonary adenocarcinoma (PA) via regulation of dendritic cells (DCs). However, the molecular mechanism of DCs in PA is still unclear. The present work showed that CYLD-/- mice have a shorter survival rate of PA, and knockout CYLD in DCs also repress the progression of PA in mice. Subsequently, we found that decreased expression and reduced the nuclear translocation of NF-κB signalling was observed in CYLD knockout DCs, and inhibiting NF-κB pathway repressed DCs-induced proliferation and function of CD4+ T cells. These results indicated that CYLD function as a tumour suppresser in PA via regulates the function of DCs through NF-κB signalling pathway. Our findings support that CYLD serves as a potential target for immunotherapy in PA.


Assuntos
Adenocarcinoma de Pulmão/imunologia , Adenocarcinoma de Pulmão/patologia , Células Dendríticas/metabolismo , Enzima Desubiquitinante CYLD/metabolismo , Imunomodulação , NF-kappa B/metabolismo , Transdução de Sinais/imunologia , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/metabolismo , Animais , Linfócitos T CD4-Positivos/citologia , Proliferação de Células , Células Dendríticas/imunologia , Enzima Desubiquitinante CYLD/deficiência , Enzima Desubiquitinante CYLD/genética , Progressão da Doença , Técnicas de Inativação de Genes , Camundongos
16.
J Cell Mol Med ; 24(2): 2052-2063, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31883300

RESUMO

Studies have demonstrated that nuclear factor of activated T cells 5 (NFAT5) is not only a tonicity-responsive transcription factor but also activated by other stimuli, so we aim to investigate whether NFAT5 participates in collateral arteries formation in rats. We performed femoral artery ligature (FAL) in rats for hindlimb ischaemia model and found that NFAT5 was up-regulated in rat adductors with FAL compared with sham group. Knockdown of NFAT5 with locally injection of adenovirus-mediated NFAT5-shRNA in rats significantly inhibited hindlimb blood perfusion recovery and arteriogenesis. Moreover, NFAT5 knockdown decreased macrophages infiltration and monocyte chemotactic protein-1 (MCP-1) expression in rats adductors. In vitro, with interleukin-1ß (IL-1ß) stimulation and loss-of-function studies, we demonstrated that NFAT5 knockdown inhibits MCP-1 expression in endothelial cells and chemotaxis of THP-1 cells regulated by ERK1/2 pathway. More importantly, exogenous MCP-1 delivery could recover hindlimb blood perfusion, promote arteriogenesis and macrophages infiltration in rats after FAL, which were depressed by NFAT5 knockdown. Besides, NFAT5 knockdown also inhibited angiogenesis in gastrocnemius muscles in rats. Our results indicate that NFAT5 is a critical regulator of arteriogenesis and angiogenesis via MCP-1-dependent monocyte recruitment, suggesting that NFAT5 may represent an alternative therapeutic target for ischaemic diseases.

18.
Anal Cell Pathol (Amst) ; 2019: 9684175, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31886122

RESUMO

This study is aimed at investigating the lymphocyte subsets of cerebrospinal fluid (CSF) to provide possible differential diagnostic values and better understand the pathophysiological mechanism underlying autoimmune encephalitis (AE) and infectious lymphocytic encephalitis. A series of CD markers, including CD3/4/8/20 representing different types and developmental stages of lymphocytes, were used to count the corresponding subpopulations of CSF from clinical and laboratory confirmed cases of anti-N-methyl-D-aspartate receptor AE (NMDAR-AE), herpes simplex virus encephalitis (HSVE), and tuberculous meningitis (TBM). The percentages of lymphocytes observed and the CD4 : CD8 ratios were compared between the three groups. There were no significant differences of the percentage of total lymphocytes, CD3 cells, and CD4 cells of CSF among each group. However, there were strongly statistical differences of the CD4 : CD8 ratio in CSF of each group with 0.6 : 1 in NMDAR-AE, 0.9 : 1 in HSVE, and 3.2 : 1 in TBM. The percentage of CD20 B lymphocytes in NMDAR-AE was statistically higher than that of other groups. The distinct percentages of lymphocyte subpopulations of CSF appeared to be characteristic and could potentially serve as diagnostic indicators. Further verification and research will be necessary to clarify the significance and nature of CD4 : CD8 ratios and B lymphocytes in CSF between AE and the infectious lymphocytic encephalitis.


Assuntos
Líquido Cefalorraquidiano/imunologia , Encefalite/diagnóstico , Encefalite/imunologia , Doença de Hashimoto/diagnóstico , Doença de Hashimoto/imunologia , Subpopulações de Linfócitos/imunologia , Adulto , Linfócitos B/imunologia , Diagnóstico Diferencial , Encefalite/líquido cefalorraquidiano , Feminino , Doença de Hashimoto/líquido cefalorraquidiano , Humanos , Masculino , Linfócitos T/imunologia
19.
Huan Jing Ke Xue ; 40(12): 5473-5483, 2019 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854620

RESUMO

In sustainable development assessment of the Beijing-Tianjin-Hebei region, the ability to dynamically estimate the value of ecosystem services is of great significance. This study considers the Beijing-Tianjin-Hebei region as the research area, based on the google earth engine (GEE); the classification and decision tree (CART) classification algorithm was adopted to supervise and classify the Landsat Thematic Mapper/Operational Land Imager (TM/OLI) images in the study area in 1998, 2003, 2008, 2013, and 2018, and land use types in these five periods were obtained. Quantitative analysis of the dynamic changes of land use in the Beijing-Tianjin-Hebei region from 1998 to 2018 was carried out. Then, the ecosystem service value (ESV) equivalent estimation method was used to quantitatively estimate the ESV in the Beijing-Tianjin-Hebei region and combine it with a 15 km×15 km scale grid to detect its temporal and spatial dynamics. The main results were as follows. ① From 1998 to 2018, the area of construction land (increased by 16.67%) and grassland (reduced by 13.73%) in the six land use types in the Beijing-Tianjin-Hebei region was the largest, and the change in the proportion of water bodies (0.2%) was the smallest. ② The total value of ESV in the Beijing-Tianjin-Hebei region experienced a short-term increase from 1998 to 2003 (an increase of 91.97×108 yuan), and continued to decrease from 2003 to 2018 (a decrease of 239.07×108 yuan), mainly related to the expansion of construction land area in the other three time periods excluding 1998 and 2003. Among the six land use types, the forest provides the highest value of ecosystem services, and the construction land and unused land provide the lowest value of ecosystem services. ③ The ESV time-space analysis based on the 15 km×15 km scale grid showed that the ESV medium area in the Beijing-Tianjin-Hebei region gradually decreased from 1998 to 2018, the ESV lower area and the higher area gradually increased, and the ESV lower-area growth rate was higher than for the higher area. ④ The revised value of the Beijing-Tianjin-Hebei region (sensitivity coefficient range 0-0.83) has good significance and reliability. In future economic development, the Beijing-Tianjin-Hebei region should rationally optimize the land use pattern and strengthen the protection of forest land, grassland, water bodies and cultivated land.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Florestas , Agricultura , Pequim , China , Reprodutibilidade dos Testes
20.
Front Microbiol ; 10: 2435, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31708903

RESUMO

Anthropogenically-impacted environments offer the opportunity to discover novel microbial species and metabolisms, which may be undetectable in natural systems. Here, a combined metagenomic and geochemical study in Base Mine Lake, Alberta, Canada, which is the only oil sands end pit lake to date, revealed that nitrification was performed by members from Nitrosomonadaceae, Chloroflexi and unclassified Gammaproteobacteria "MBAE14." While Nitrosomonadaceae and Chloroflexi groups were relatively abundant in the upper oxygenated zones, MBAE14 dominated the hypoxic hypolimnetic zones (approximately 30% of total microbial communities); MBAE14 was not detected in the underlying anoxic tailings. Replication rate analyses indicate that MBAE14 grew in metalimnetic and hypolimnetic water cap regions, most actively at the metalimnetic, ammonia/oxygen transition zone consistent with it putatively conducting nitrification. Detailed genomic analyses of MBAE14 evidenced both ammonia oxidation and denitrification into dinitrogen capabilities. However, the absence of known CO2-fixation genes suggests a heterotrophic denitrifying metabolism. Functional marker genes of ammonia oxidation (amo and hao) in the MBAE14 genome are homologous with those conserved in autotrophic nitrifiers, but not with those of known heterotrophic nitrifiers. We propose that this novel MBAE14 inhabits the specific ammonia-rich, oxygen and labile organic matter-limited conditions occurring in Base Mine Lake which selectively favors mixotrophic coupled nitrifier denitrification metabolism. Our results highlight the opportunities to better constrain biogeochemical cycles from the application of metagenomics to engineered systems associated with extractive resource sectors.

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