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1.
Genome Med ; 12(1): 41, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32349779

RESUMO

BACKGROUND: Cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)/CHOP-like chemotherapy is widely used in peripheral T cell lymphoma (PTCL). Here we conducted a phase 2, multicenter, randomized, controlled trial, comparing the efficacy and safety of CEOP/IVE/GDP alternating regimen with CEOP in newly diagnosed PTCL. METHODS: PTCL patients, except for anaplastic large cell lymphoma-anaplastic lymphoma kinase positive, were 1:1 randomly assigned to receive CEOP/IVE/GDP (CEOP, cyclophosphamide 750 mg/m2, epirubicin 70 mg/m2, vincristine 1.4 mg/m2 [maximum 2 mg] on day 1, and prednisone 60 mg/m2 [maximum 100 mg] on days 1-5 every 21 days, at the first and fourth cycle; IVE, ifosfamide 2000 mg/m2 on days 1-3, epirubicin 70 mg/m2 on day 1, and etoposide 100 mg/m2 on days 1-3 every 21 days, at the second and fifth cycle; and GDP, gemcitabine 1000 mg/m2 on days 1 and 8, cisplatin 25 mg/m2 on days 1-3, and dexamethasone 40 mg on days 1-4 every 21 days, at the third and sixth cycle) and CEOP (every 21 days for 6 cycles). Analysis of efficacy and safety was of the intent-to-treatment population. The primary endpoint was a complete response rate at the end of treatment. Meanwhile, whole exome sequencing and targeted sequencing were performed in 62 patients with available tumor samples to explore prognostic biomarkers in this cohort as an exploratory post hoc analysis. RESULTS: Among 106 patients, 53 each were enrolled to CEOP/IVE/GDP and CEOP. With 51 evaluable patients each in two groups, a complete response rate of the CEOP/IVE/GDP group was similar to that of the CEOP group (37.3% vs. 31.4%, p = 0.532). There was no difference in median progression-free survival (PFS; 15.4 months vs. 9.2 months, p = 0.122) or overall survival (OS; 24.3 months vs. 21.9 months, p = 0.178). Grade 3-4 hematological and non-hematological adverse events were comparable. Histone modification genes were most frequently mutated (25/62, 40.3%), namely KMT2D, KMT2A, SETD2, EP300, and CREBBP. Multivariate analysis indicated that CREBBP and IDH2 mutations were independent factors predicting poor PFS and OS (all p < 0.001), while KMT2D predicting poor PFS (p = 0.002). CONCLUSIONS: CEOP/IVE/GDP alternating regimen showed no remission or survival advantage to standard chemotherapy. Future clinical trials should aim to develop alternative regimen targeting disease biology as demonstrated by recurrent mutations in epigenetic factors. TRIAL REGISTRATION: The study was registered on ClinicalTrial.gov (NCT02533700) on August 27, 2015.

2.
Sci Total Environ ; 724: 138183, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32408446

RESUMO

To assess the effects of nitrogen deposition on forest plants, researchers have conducted many nitrogen-addition experiments. Most of these experiments, however, failed to fully simulate atmospheric nitrogen deposition because they failed to assess interception of nitrogen deposition by the forest canopy. Here, we used transcriptomics, proteomics, and metabolomics to compare the effects of understory nitrogen addition (UAN), canopy nitrogen addition (CAN), and a control (no nitrogen addition) on carbon and nitrogen metabolism in leaves of Psychotria rubra, a dominant subtropical understory plant species in evergreen broad-leaved forests in South China. We first established a reference P. rubra transcriptome via RNA-seq and obtained a total of 93,986 unigenes from de novo assembly. Next, we quantitatively investigated the proteome and metabolome in leaves, and identified 4021 proteins and 562 metabolites. Under the CAN treatment and relative to the control, 36 genes were up-regulated and 23 were down-regulated, and we identified 46 up-regulated proteins and 49 down-regulated proteins. Under the UAN treatment and relative to the control, 1525 genes were up-regulated and 224 genes down-regulated, and we identified 35 up-regulated proteins and 71 down-regulated proteins. These differentially expressed genes and proteins were related to photosynthesis, amino acid metabolism, and flavonoid biosynthesis. Accordingly, 15 differentially accumulated metabolites in response to CAN and 20 in response to UAN were found; these differentially accumulated metabolites included 4 amino acids and 3 flavonoids. Taken together, our results show that the UAN treatment had a greater effect on photosynthesis, amino acid metabolism, and flavonoid biosynthesis than the CAN treatment. Most importantly, the results indicate that understory application of nitrogen in experiments may incorrectly estimate the effects of nitrogen deposition on nitrogen and carbon utilization by P. rubra and perhaps by other understory woody plants in the evergreen broad-leaved forests in South China as well.

3.
Phys Rev Lett ; 124(17): 171101, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32412296

RESUMO

The astrophysical reach of current and future ground-based gravitational-wave detectors is mostly limited by quantum noise, induced by vacuum fluctuations entering the detector output port. The replacement of this ordinary vacuum field with a squeezed vacuum field has proven to be an effective strategy to mitigate such quantum noise and it is currently used in advanced detectors. However, current squeezing cannot improve the noise across the whole spectrum because of the Heisenberg uncertainty principle: when shot noise at high frequencies is reduced, radiation pressure at low frequencies is increased. A broadband quantum noise reduction is possible by using a more complex squeezing source, obtained by reflecting the squeezed vacuum off a Fabry-Perot cavity, known as filter cavity. Here we report the first demonstration of a frequency-dependent squeezed vacuum source able to reduce quantum noise of advanced gravitational-wave detectors in their whole observation bandwidth. The experiment uses a suspended 300-m-long filter cavity, similar to the one planned for KAGRA, Advanced Virgo, and Advanced LIGO, and capable of inducing a rotation of the squeezing ellipse below 100 Hz.

4.
BMC Pharmacol Toxicol ; 21(1): 34, 2020 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-32384920

RESUMO

BACKGROUND: Air pollution increases the morbidity and mortality of cardiovascular disease (CVD). Atherosclerosis (AS) is the pathological basis of most CVD, and the progression of atherosclerosis and the increase of fragile plaque rupture are the mechanism basis of the relationship between atmospheric particulate pollution and CVD. The aim of the present study was to investigate the effects of coal-fired fine particulate matter (PM2.5) on the expression levels of atherosclerosis-related proteins (von Willebrand factor (vWF), Endothelin-1 (ET-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin, and to explore the role and mechanism of the progression of atherosclerosis induced by coal-fired PM2.5 via the mitogen-activated protein kinase (MAPK) signaling pathways. METHODS: Different concentrations of PM2.5 were given to apolipoprotein-E knockout (ApoE-/-) mice via intratracheal instillation for 8 weeks. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of vWF, ET-1 in serum of mice. Immunohistochemistry was used to observe the expression and distribution of ICAM-1 and E-selectin in the aorta of mice. Western blot was used to investigate the phosphoylation of proteins relevant to MAPK signaling pathways. RESULTS: Coal-fired PM2.5 exacerbated atherosclerosis induced by a high-fat diet. Fibrous cap formation, foam cells accumulation, and atherosclerotic lesions were observed in the aortas of PM2.5-treated mice. Coal-fired PM2.5 increased the protein levels of ET-1, ICAM-1, and E-selectin, but there was no significant difference in the vWF levels between the PM2.5-treatment mice and the HFD control mice. Coal-fired PM2.5 promoted the phosphorylation of p38, c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) in aortic tissues of mice. CONCLUSION: Coal-derived PM2.5 exacerbated the formation of atherosclerosis in mice, increased the expression levels of atherosclerosis-related proteins in mice serum, and promoted the phosphorylation of proteins relevant to MAPK signaling pathway. Thus, MAPK signaling pathway may play a role in the atherosclerosis pathogenesis induced by Coal-derived PM2.5.

5.
Chemosphere ; 253: 126648, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32298911

RESUMO

Catalyzed H2O2 propagations (CHP) have demonstrated great potential in the remediation of chlorinated aliphatic hydrocarbons (CAHs) like trichloroethene (TCE) contaminated groundwater. However, the importation of highly unstable H2O2 into subsurface environment remains challenging. In this work, the in-situ H2O2 generation reaction between glucose oxidase (GOD) and glucose was applied in combination with Fe(II) to form the modified Fenton system (GMFs) and its performance in TCE oxidative degradation was investigated. The influence of reactant concentration as well as environmental factors like temperature and pH on the kinetics of TCE oxidation in GMFs were studied. At optimized conditions, about 78% TCE were removed within 8 h in GMFs, which remained effective over the temperature range of 15-30 °C and pH range of 3.6-6.0 (in acetate buffer). The in-situ H2O2 and OH generation capacity of GMFs were further investigated to elucidate their functional mechanism on TCE oxidation. Intermediate and product analysis indicated the near-complete release of chloride ion by TCE oxidation with few organic chlorinated intermediates detected. This work reveals the potential of GMFs for CAHs contaminated groundwater remediation through in-situ generation of reactive oxygen species.

6.
Int J Nurs Pract ; : e12837, 2020 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-32314501

RESUMO

AIM: The present study aimed to evaluate the effectiveness of individualized exercise counselling in changing exercise behaviour and relieving pregnancy-related distress symptoms in pregnant women. METHODS: A quasi-experimental design and convenience sampling technique were used. Participants were recruited from the prenatal outpatient departments of medical centre hospitals in Taipei, Taiwan. The experimental group (n = 52) received face-to-face exercise counselling followed by 8 weeks of exercise sessions in their homes. The control group (n = 49) received no exercise counselling. Pregnancy-related distress symptoms were assessed before and after 8 weeks in both groups. RESULTS: The after-counselling scores of total (t = 2.46, P < 0.05) and physical (t = 3.18, P < 0.01) distress symptoms were significantly lower than the before-counselling scores in the experimental group. The total, physical and psychological distress scores significantly differed between groups and before and after counselling. The adjusted R2 values for total, physical and psychological distress symptoms ranged from 0.59 to 0.70. Participants' exercise habits increased from prepregnancy (19.2%) to after counselling (71.2%). CONCLUSION: Exercise counselling may effectively increase exercise habits and reduce pregnancy-related distress symptoms among pregnant women. Women with higher pretest symptom distress scores also had higher posttest symptom distress scores. Based on our outcomes, health care providers should routinely provide exercise counselling to pregnant women.

7.
Chemosphere ; 250: 126325, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32234625

RESUMO

Atmospheric carbon dioxide (CO2) imbalance due to anthropogenic emissions has direct impact in climate change. Recent advancements in the mitigation of industrial CO2 emissions have been brought about by a paradigm shift from mere CO2 capture onto various adsorbents to CO2 conversion into high value products. The present study proposes a system which involves the conversion of CO2 into high purity, low moisture, compact and large CaCO3 solids through homogeneous granulation in a fluidized-bed reactor (FBR). In the present study, synthetic solutions of potassium carbonate (K2CO3) and calcium hydroxide (Ca(OH)2) were used as sources of carbonate and precipitant, respectively. The effects of the degree of supersaturation (S) as chemical loading and influx flow rate (QT) as hydraulic loading on CaCO3 granulation efficiency were investigated. In the study, S was varied from 10.2 to 10.8 and QT from 40 to 80 mL min-1 while the operating pH and calcium-is-to-carbonate molar ratio ([Ca2+]/[CO32-]) were set at 10 ± 0.2 and 1.50, respectively. Results showed that carbonate ions end product distribution had a highest carbonate granulation efficiency at [Carbonate]G of 95-96% using S of 10.6 and QT of 60 mL min-1. Characterization of the granules confirmed high purity calcium carbonate. Overall, the transformation of industrial CO2 emissions into a valuable solid product can be a significant move towards the mitigation of climate change from anthropogenic emissions.

8.
Mol Cell Probes ; : 101578, 2020 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-32334007

RESUMO

Recent studies suggested SRY-related high mobility group box 30 (SOX30) as a candidate tumor-promoter or tumor-inhibitor in multiple tumor types. Yet, the detailed role of SOX30 in acute myeloid leukemia (AML) has not been well studied. The present research was designed to investigate the detailed relevance of SOX30 in AML. The data of our study indicated that SOX30 expression was markedly downregulated in AML cells, a pattern associated with its hypermethylation. SOX30 overexpression caused a marked reduction in AML cell proliferation and colony formation, but it promoted AML cell apoptosis. By contrast, SOX30 depletion by small interfering RNA (siRNA)-mediated gene silencing had the opposite effect. Moreover, SOX30 overexpression markedly decreased ß-catenin expression, a change that led to inactivation of Wnt/ß-catenin pathway. Notably, restoration of ß-catenin expression partially reversed SOX30-mediated tumor suppressive effect in AML cells. In an AML-derived mouse xenograft model, SOX30 overexpression remarkably retarded the tumor growth in vivo. Overall, these data of the study suggest a tumor-inhibition role of SOX30 in AML, and highlight a key role of SOX30/Wnt/ß-catenin axis in the progression of AML.

9.
Sci Total Environ ; 727: 138738, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-32334237

RESUMO

Simulated nitrogen deposition experiments in forests have mainly used understory nitrogen application, i.e., they failed to consider how canopy interception may alter the effects of nitrogen deposition on forest plants. This study used canopy addition of nitrogen, understory addition of nitrogen, and no-nitrogen addition control to study the effect of nitrogen deposition on the allocation of carbon assimilation products of representative woody species in an evergreen broad-leaved forest. Results showed that the maximum photosynthetic rate (Asat) of Blastus cochinchinensis (a shrub), Ardisia quinquegona (a small tree), and Schefflera octophylla (a small tree) were significantly higher, but Asat of Schima superba (a large tree) was significantly lower under canopy addition of nitrogen than under the control. Canopy and understory additions of nitrogen did not change Asat of Lasianthus chinensis (a shrub). Compared with the control, leaf chemical compositions of these plants were differentially changed by canopy and understory additions of nitrogen. These changes were accompanied by a significant increase in construction cost of A. quinquegona, S. octophylla, and S. superba under canopy addition of nitrogen and of L. chinensis, A. quinquegona, and S. superba under understory addition of nitrogen. The payback time was significantly shorter for B. cochinchinensis, A. quinquegona, and S. octophylla but was significantly longer for S. superba under canopy addition of nitrogen than under the control. In contrast, the payback time was significantly shorter for B. cochinchinensis and A. quinquegona under understory addition of nitrogen than under the control. Correlation analyses showed that the changes in protein and structural carbohydrate contents helped explain the changes in payback time. In summary, nitrogen deposition may increase carbon assimilation and allocation in shrubs and small trees, and large trees may require a longer period to increase carbohydrates, which may help explain the ongoing transformation of evergreen broad-leaved forests into shrublands.

10.
Diabetes Ther ; 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32166620

RESUMO

INTRODUCTION: With longer duration and progression of type 2 diabetes (T2D), ß-cell function deteriorates and insulin therapy often becomes necessary. Glucagon-like peptide-1 receptor agonists such as lixisenatide that do not rely only on ß-cell function and glucagon suppression primarily, but also lower glucose by other (insulin-independent) mechanisms such as delayed gastric emptying, may be appropriate adjuvant therapy to basal insulin in patients with longstanding T2D. METHODS: We assessed the efficacy and safety of insulin glargine (iGlar) versus iGlarLixi, a fixed-ratio combination of iGlar and lixisenatide, stratified by quartiles (Q) of T2D duration (≤ 7.305 [Q1], > 7.305 to ≤ 10.75 [Q2], > 10.75 to ≤ 15.67 [Q3], and > 15.67 years [Q4]) in the LixiLan-L trial (N = 736). RESULTS: Across all quartiles, the reduction in glycated haemoglobin was greater with iGlarLixi versus iGlar, and the difference was most pronounced in patients with the longest duration (Q4; least squares mean difference [standard error] - 0.62 [0.13], P < 0.0001). Additionally, hypoglycaemia rates were significantly lower with iGlarLixi versus iGlar in patients in Q4 (3.3 vs. 6.9 events/patient-year, P < 0.0001). CONCLUSION: iGlarLixi lowered glycated haemoglobin more versus iGlar regardless of T2D duration, with benefit retained even among patients with the longest T2D duration.

13.
Heart Surg Forum ; 23(1): E001-E006, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-32118534

RESUMO

BACKGROUND: The use of a sequential vein graft (SVG) in coronary artery bypass grafting (CABG) in multi-vessel coronary disease is common. This study aimed to investigate the influence of the paths of SVGs on the outcomes of CABG. METHODS: From January 2011 to June 2017, 126 patients underwent elective isolated CABG. If the path of the SVG was from the aorta to the right coronary artery (RCA)/ posterior descending artery (PDA) to the left circumflex artery (LCX)/obtuse marginal artery (OM), the patients were included in Group R. If the path was from the aorta to the LCX/OM to the RCA/PDA, the patients were included in Group L. The in-hospital and follow-up outcomes were analyzed. RESULTS: Group R had 69 patients, and Group L had 57 patients. Univariate analysis showed that Group L had a higher number of grafts (P < .001) and less aortic cross-clamping time (P < .001) and total bypass time (P = .001). Otherwise, Group L had 14 patients (19.3%), who received first diagonal branch (D1) bypass grafting, while Group R had none (P < .001). In the multivariate analysis, in- hospital mortality from heart failure, postoperative acute kidney injury, medium-term mortality, and readmission for cardiac incidents were not associated with the SVG path. CONCLUSION: The SVG path from the aorta to the LCX/OM to the RCA/PDA facilitated the additional D1 bypass grafting, but the outcomes for this approach were not significantly different from those for the other path.

14.
Emerg Microbes Infect ; 9(1): 366-377, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32056513

RESUMO

Hepatitis B virus (HBV) is a partially double-stranded DNA virus that replicates by reverse transcription. We previously demonstrated that the host restriction factor-APOBEC3B (A3B) inhibited HBV replication which was dependent on its deaminase activity during reverse transcription. However, the host factors involved in the process of regulating the anti-HBV function of A3B are less known. In this research, to obtain a comprehensive understanding of the interaction networks of A3B, we conducted coimmunoprecipitation and mass spectrometry to identify A3B-interacting proteins in the presence of HBV. By this approach, we determined that DExD/H-box helicase 9 (DHX9) suppressed the anti-HBV effect of A3B, and this suppression was dependent on their interaction. Although DHX9 did not affect the deamination activity of A3B in vitro assay or the viral DNA editing of A3B in HepG2-NTCP cells that support HBV infection, it inhibited the binding of A3B with pgRNA. These data suggest that DHX9 can interact with A3B and attenuate the anti-HBV efficacy of A3B.Abbreviations: 3D-PCR: differential DNA denaturation PCR; APOBEC3: apolipoprotein B mRNA-editing catalytic polypeptide 3; cccDNA: covalently closed circular DNA; co-IP: coimmunoprecipitation; DDX: DExD-box RNA helicases; HBc: HBV core protein; HBV: hepatitis B virus; HepAD38: HepG2 cell line stably transfected with HBV DNA; HepG2-NTCP: HepG2 cell line stably transfected with Na+/taurocholate cotransporter polypeptide; Huh7: human hepatoma cell line; pgRNA: pregenomic RNA; PPI: protein-protein interactions; RC DNA: relaxed circular DNA.


Assuntos
Citidina Desaminase/metabolismo , RNA Helicases DEAD-box/metabolismo , Hepatite B/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismo , Proteínas de Neoplasias/metabolismo , Células HEK293 , Células Hep G2 , Vírus da Hepatite B/fisiologia , Humanos , Ligação Proteica , Mapeamento de Interação de Proteínas , RNA Viral , Replicação Viral
15.
Emerg Microbes Infect ; 9(1): 457-468, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32090689

RESUMO

Porcine deltacoronavirus (PDCoV) is a newly emerging threat to the global porcine industry. PDCoV has been successfully isolated using various medium additives including trypsin, and although we know it is important for viral replication, the mechanism has not been fully elucidated. Here, we systematically investigated the role of trypsin in PDCoV replication including cell entry, cell-to-cell membrane fusion and virus release. Using pseudovirus entry assays, we demonstrated that PDCoV entry is not trypsin dependent. Furthermore, unlike porcine epidemic diarrhea virus (PEDV), in which trypsin is important for the release of virus from infected cells, PDCoV release was not affected by trypsin. We also demonstrated that trypsin promotes PDCoV replication by enhancing cell-to-cell membrane fusion. Most importantly, our study illustrates two distinct spreading patterns from infected cells to uninfected cells during PDCoV transmission, and the role of trypsin in PDCoV replication in cells with different virus spreading types. Overall, these results clarify that trypsin promotes PDCoV replication by mediating cell-to-cell fusion transmission but is not crucial for viral entry. This knowledge can potentially contribute to improvement of virus production efficiency in culture, not only for vaccine preparation but also to develop antiviral treatments.


Assuntos
Fusão Celular , Coronavirus/fisiologia , Fusão de Membrana , Tripsina/metabolismo , Animais , Linhagem Celular , Humanos , Suínos , Internalização do Vírus , Replicação Viral
17.
Comput Methods Programs Biomed ; 190: 105360, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-32007838

RESUMO

BACKGROUND AND OBJECTIVES: Automated breast ultrasound (ABUS) is a widely used screening modality for breast cancer detection and diagnosis. In this study, an effective and fast computer-aided detection (CADe) system based on a 3-D convolutional neural network (CNN) is proposed as the second reader for the physician in order to decrease the reviewing time and misdetection rate. METHODS: Our CADe system uses the sliding window method, a CNN-based determining model, and a candidate aggregation algorithm. First, the sliding window method is performed to split the ABUS volume into volumes of interest (VOIs). Afterward, VOIs are selected as tumor candidates by our determining model. To achieve higher performance, focal loss and ensemble learning are used to solve data imbalance and reduce false positive (FP) and false negative (FN) rates. Because several selected candidates may be part of the same tumor and they may overlap each other, a candidate aggregation method is applied to merge the overlapping candidates into the final detection result. RESULTS: In the experiments, 165 and 81 cases are utilized for training the system and evaluating system performance, respectively. On evaluation with the 81 cases, our system achieves sensitivities of 100% (81/81), 95.3% (77/81), and 90.9% (74/81) with FPs per pass (per case) of 21.6 (126.2), 6.0 (34.8), and 4.6 (27.1) respectively. According to the results, the number of FPs per pass (per case) can be diminished by 56.8% (57.1%) at a sensitivity of 95.3% based on our tumor detection model. CONCLUSIONS: In conclusion, our CADe system using 3-D CNN with the focal loss and ensemble learning may have the capability of being a tumor detection system in ABUS image.

18.
Glob Chang Biol ; 26(5): 3163-3173, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32048403

RESUMO

The area of forest established through afforestation/reforestation has been increasing on a global scale, which is particularly important as these planted forests attenuate climate change by sequestering carbon. However, the determinants of soil organic carbon (SOC) sequestration and their contribution to the ecosystem carbon sink of planted forests remain uncertain. By using globally distributed data extracted from 154 peer-reviewed publications and a total of 355 sampling points, we investigated above-ground biomass carbon (ABC) sequestration and SOC sequestration across three different climatic zones (tropical, warm temperate, and cold temperate) through correlation analysis, regression models, and structural equation modeling (SEM). We found that the proportion of SOC sequestration in the ecosystem C sequestration averaged 14.1% globally, being the highest (27.0%) in the warm temperate and the lowest (10.7%) in the tropical climatic zones. The proportion was mainly affected by latitude. The sink rate of ABC (RABC ) in tropical climates (2.48 Mg C ha-1  year-1 ) and the sink rate of SOC (RSOC ) in warm temperate climates (0.96 Mg C ha-1  year-1 ) were higher than other climatic zones. The main determinants of RSOC were the number of frost-free days, latitude, mean annual precipitation (MAP), and SOC density (SOCD) at the initial observation; however, these variables depended on the climatic zone. According to the SEM, frost-free period, mean annual temperature (MAT) and MAP are the dominant driving factors affecting RSOC in Chinese plantations. MAT has a positive effect on RSOC , and global warming may increase RSOC of temperate plantations in China. Our findings highlight the determinants of SOC sequestration and quantitatively reveal the substantial global contribution of SOC sequestration to ecosystem carbon sink provided by planted forests. Our results help managers identify and control key factors to increase carbon sequestration in forest ecosystems.

19.
Ecol Lett ; 23(5): 821-830, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32100414

RESUMO

Grassland ecosystems account for more than 10% of the global CH4 sink in soils. A 4-year field experiment found that addition of P alone did not affect CH4 uptake and experimental addition of N alone significantly suppressed CH4 uptake, whereas concurrent N and P additions suppressed CH4 uptake to a lesser degree. A meta-analysis including 382 data points in global grasslands corroborated these findings. Global extrapolation with an empirical modelling approach estimated that contemporary N addition suppresses CH4 sink in global grassland by 11.4% and concurrent N and P deposition alleviates this suppression to 5.8%. The P alleviation of N-suppressed CH4 sink is primarily attributed to substrate competition, defined as the competition between ammonium and CH4 for the methane mono-oxygenase enzyme. The N and P impacts on CH4 uptake indicate that projected increases in N and P depositions might substantially affect CH4 uptake and alter the global CH4 cycle.


Assuntos
Metano , Nitrogênio , Ecossistema , Pradaria , Fósforo , Solo
20.
Int J Syst Evol Microbiol ; 70(3): 1861-1867, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32017675

RESUMO

A novel strain, designated AQ6-296T, was isolated from a soil sample collected in Fildes Peninsula, Antarctic. Cells were Gram-stain-negative, non-endospore-forming, non-motile, strictly aerobic and rod-shaped. Growth occurred at 4-28 °C (optimum, 20 °C) and at pH 6.0-7.0 (optimum, pH 7.0). NaCl was not obligatory for growth. Colonies were pale yellow after growth for 3 days at 20 °C on Reasoner's 2A agar. The strain was weakly positive for oxidase and the catalase test was negative. The only respiratory quinone was Q-8. The predominant cellular fatty acids were iso-C16 : 0, iso-C15 : 0, iso-C11 : 0 3OH, summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 9 (comprising iso-C17 : 1ω9c and/or C16 : 010-methyl). The major polar lipids were phosphatidylethanolamine, unknown aminolipids, phosphatidylglycerol and diphosphatidylglycerol. The results of phylogenetic analysis based on 16S rRNA gene sequences (the highest similarity at 92.4 % to Lysobacter dokdonensis) indicated that strain AQ6-296T is within the family Xanthomonadaceae. The DNA G+C content of the type strain was 58.6 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain AQ6-296T is considered to represent a novel genus and species in the family Xanthomonadaceae, for which the name Pseudolysobacter antarcticus gen. nov., sp. nov. is proposed. The type strain is AQ6-296T (CCTCC AB 2016313T=KCTC 52744T).


Assuntos
Filogenia , Microbiologia do Solo , Xanthomonadaceae/classificação , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química , Xanthomonadaceae/isolamento & purificação
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