ABSTRACT
The conversion of farmland to forest in China has been recognized for its positive impact on above-ground vegetation and carbon sequestration. However, the impact on soil quality during land conversion, particularly in vulnerable karst areas, has received less attention. In this study conducted in a karst area of southwest China, eight different farmland conversion strategies were investigated to assess improvements in surface soil carbon, nitrogen, and ecosystem multi-functionality (EMF). Our results showed that farmland converted to afforestation areas or farmland that was abandoned contained higher amounts of carbon (total, organic, active) and ammonium nitrogen (NH4+-N) in the soil compared to farmland converted to grassland or maize crop. Soluble organic carbon levels were higher in afforestation and grassland areas compared to maize crop controls. By contrast, soil from grassland and abandoned land exhibited higher levels of nitrate nitrogen (NO3--N) compared to afforestation land or maize crop controls. There were no differences in NH4+-N content between any condition, except for afforestation land that specifically contained the Zenia insignis plant species. Afforestation land consistently exhibited higher EMF values than grassland. Pearson correlation analysis revealed positive relationships between soil indices and EMF scores, except for NO3--N.Random forest analysis explained 95% of the variation in soil EMF and identified specific soil factors: total carbon, organic carbon, active labile organic carbon, total nitrogen, and ammonium nitrogen, as the main drivers of soil multi-functionality. Our studies show how various reforestation strategies can enhance soil nutrient sequestration and improve soil multi-functionality of farmland in the karst areas.These findings provide insight into sustainable soil management practices for converting farmland into natural areas.
Subject(s)
Carbon , Ecosystem , Forests , Grassland , Nitrogen , Soil , Carbon/analysis , Soil/chemistry , China , Nitrogen/analysis , Farms , Agriculture/methodsABSTRACT
Acute respiratory distress syndrome (ARDS) is a serious respiratory condition characterized by a damaged pulmonary endothelial barrier that causes protein-rich lung edema, an influx of proinflammatory cells, and treatment-resistant hypoxemia. Damage to pulmonary endothelial cells and inflammation are pivotal in ARDS development with a key role played by endothelial cell pyroptosis. Disulfiram (DSF), a drug that has long been used to treat alcohol addiction, has recently been identified as a potent inhibitor of gasdermin D (GSDMD)-induced pore formation and can thus prevent pyroptosis and inflammatory cytokine release. These findings indicate that DSF is a promising treatment for inflammatory disorders. However, addressing the challenge posed by its intrinsic physicochemical properties, which hinder intravenous administration, and effective delivery to pulmonary vascular endothelial cells are crucial. Herein, we used biocompatible liposomes incorporating a lung endothelial cell-targeted peptide (CGSPGWVRC) to produce DSF-loaded nanoparticles (DTP-LET@DSF NPs) for targeted delivery and reactive oxygen species-responsive release facilitated by the inclusion of thioketal (TK) within the liposomal structure. After intravenous administration, DTP-LET@DSF NPs exhibited excellent cytocompatibility and minor systemic toxicity, effectively inhibited pyroptosis, mitigated lipopolysaccharide (LPS)-induced ARDS, and prevented cytokine storms resulting from excessive immune reactions in ARDS mice. This study presents a straightforward nanoplatform for ARDS treatment that potentially paves the way for the clinical use of this nanomedicine.
Subject(s)
Disulfiram , Respiratory Distress Syndrome , Animals , Mice , Disulfiram/pharmacology , Endothelial Cells , Drug Repositioning , Respiratory Distress Syndrome/drug therapy , Lung , Liposomes/pharmacology , Lipopolysaccharides/pharmacologyABSTRACT
BACKGROUND: Photoperiod, or the length of the day, has a significant impact on the flowering and sex differentiation of photoperiod-sensitive crops. The "miben" pumpkin (the main type of Cucurbita moschata Duch.) is well-known for its high yield and strong disease resistance. However, its cultivation has been limited due to its sensitivity to photoperiod. This sensitivity imposes challenges on its widespread cultivation and may result in suboptimal yields in regions with specific daylength conditions. As a consequence, efforts are being made to explore potential strategies or breeding techniques to enhance its adaptability to a broader range of photoperiods, thus unlocking its full cultivation potential and further promoting its valuable traits in agriculture. RESULTS: This study aimed to identify photoperiod-insensitive germplasm exhibiting no difference in sex differentiation under different day-length conditions. The investigation involved a phenotypic analysis of photoperiod-sensitive (PPS) and photoperiod-insensitive (PPIS) pumpkin materials exposed to different day lengths, including long days (LDs) and short days (SDs). The results revealed that female flower differentiation was significantly inhibited in PPS_LD, while no differences were observed in the other three groups (PPS_SD, PPIS_LD, and PPIS_SD). Transcriptome analysis was carried out for these four groups to explore the main-effect genes of sex differentiation responsive to photoperiod. The main-effect gene subclusters were identified based on the principal component and hierarchical cluster analyses. Further, functional annotations and enrichment analysis revealed significant upregulation of photoreceptors (CmCRY1, F-box/kelch-repeat protein), circadian rhythm-related genes (CmGI, CmPRR9, etc.), and CONSTANS (CO) in PPS_LD. Conversely, a significant downregulation was observed in most Nuclear Factor Y (NF-Y) transcription factors. Regarding the gibberellic acid (GA) signal transduction pathway, positive regulators of GA signaling (CmSCL3, CmSCL13, and so forth) displayed higher expression levels, while the negative regulators of GA signaling, CmGAI, exhibited lower expression levels in PPS_LD. Notably, this effect was not observed in the synthetic pathway genes. Furthermore, genes associated with ethylene synthesis and signal transduction (CmACO3, CmACO1, CmERF118, CmERF118-like1,2, CmWIN1-like, and CmRAP2-7-like) showed significant downregulation. CONCLUSIONS: This study offered a crucial theoretical and genetic basis for understanding how photoperiod influences the mechanism of female flower differentiation in pumpkins.
Subject(s)
Cucurbita , Cucurbita/genetics , Photoperiod , Proton Pump Inhibitors/metabolism , Sex Differentiation , Plant Breeding , Gene Expression Profiling , Flowers/metabolism , Gene Expression Regulation, PlantABSTRACT
The application of DNA barcoding has been significantly limited by the scarcity of reliable specimens and inadequate coverage and replication across all species. The deficiency of DNA barcode reference coverage is particularly striking for highly biodiverse subtropical and tropical regions. In this study, we present a comprehensive barcode library for woody plants in tropical and subtropical China. Our dataset includes a standard barcode library comprising the four most widely used barcodes (rbcL, matK, ITS, and ITS2) for 2,520 species from 4,654 samples across 49 orders, 144 families, and 693 genera, along with 79 samples identified at the genus level. This dataset also provides a super-barcode library consisting of 1,239 samples from 1,139 species, 411 genera, 113 families, and 40 orders. This newly developed library will serve as a valuable resource for DNA barcoding research in tropical and subtropical China and bordering countries, enable more accurate species identification, and contribute to the conservation and management of tropical and subtropical forests.
Subject(s)
DNA Barcoding, Taxonomic , Plants , China , Forests , Phylogeny , Plants/genetics , WoodABSTRACT
The karst forest is one of the extremely sensitive and fragile ecosystems in southwest China, where the biogeochemical cycling of mercury (Hg) is largely unknown. In this study, we investigated the litterfall deposition, accumulation, and soil migration of Hg in an evergreen-deciduous broadleaf karst forest using high-resolution sampling and stable isotope techniques. Results show that elevated litterfall Hg concentrations and fluxes in spring are due to the longer lifespan of evergreen tree foliage exposed to atmospheric Hg0. The hillslope has 1-2 times higher litterfall Hg concentration compared to the low-lying land due to the elevated atmospheric Hg levels induced by topographical and physiological factors. The Hg isotopic model suggests that litterfall Hg depositions account for â¼80% of the Hg source contribution in surface soil. The spatial trend of litterfall Hg deposition cannot solely explain the trend of Hg accumulation in the surface soil. Indeed, soil erosion enhances Hg accumulation in soil of low-lying land, with soil Hg concentration up to 5-times greater than the concentration on the hillslope. The high level of soil Hg migration in the karst forest poses significant ecological risks to groundwater and downstream aquatic ecosystems.
Subject(s)
Mercury , Soil Pollutants , Mercury/analysis , Ecosystem , Environmental Monitoring/methods , Forests , SoilABSTRACT
Plant communities strongly influence soil microbial communities and, in turn, soil carbon (C) cycling. Microbial carbon use efficiency (CUE) is an important parameter for predicting soil C accumulation, yet how plant and soil microbial community traits influence microbial CUE remains poorly understood. Here, we determined how soil microbial CUE is influenced by plant and soil microbial community traits, by studying a natural gradient of plant species diversity in a subtropical forest. Our results showed that microbial CUE increased with increasing tree species diversity, suggesting a correlation between plant community traits and soil C storage. The specific soil properties that explained the greatest variation in microbial CUE were associated with microbial communities (biomass, enzyme activities and the ratio of oligotrophic to copiotrophic taxa); there were weaker correlations with plant-input properties, soil chemistry and soil organic C quality and its mineral protection. Overall, high microbial CUE was associated with soil properties correlated with increased tree species diversity: higher substrate availability (simple SOM chemical structures and weak mineral organic associations) and high microbial growth rates despite increased community dominance by oligotrophic strategists. Our results point to a mechanism by which increased tree species diversity may increase the forest C sink by affecting carbon use with the soil microbial community.
Subject(s)
Soil , Trees , Soil/chemistry , Carbon , Soil Microbiology , Forests , MineralsABSTRACT
Phage therapy has re-emerged as a promising solution for combating antimicrobial-resistant bacterial infections. Increasingly, studies have revealed that phages possess therapeutic potential beyond their antimicrobial properties, including regulating the gut microbiome and maintain intestinal homeostasis, as a novel nanocarrier for targeted drug delivery. However, the complexity and unpredictability of phage behavior during treatment pose a significant challenge in clinical practice. The intricate interactions established between phages, humans, and bacteria throughout their long coexistence in the natural ecosystem contribute to the complexity of phage behavior in therapy, raising concerns about their efficacy and safety as therapeutic agents. Revealing the mechanisms by which phages interact with the human body will provide a theoretical basis for increased application of promising phage therapy. In this review, we provide a comprehensive summary of phage-mammal interactions, including signaling pathways, adaptive immunity responses, and phage-mediated anti-inflammatory responses. Then, from the perspective of phage-mammalian immune system interactions, we present the first systematic overview of the factors affecting phage therapy, such as the mode of administration, the physiological status of the patient, and the biological properties of the phage, to offer new insights into phage therapy for various human diseases.
Subject(s)
Bacteriophages , Phage Therapy , Animals , Humans , Bacteriophages/physiology , Ecosystem , Bacteria , Mammals , Anti-Bacterial AgentsABSTRACT
Understanding the spatial heterogeneity of soil available medium- and micro-elements in karst area can provide a valuable theoretical guideline for soil nutrient management of karst ecosystem. We collected soil samples at a soil depth of 0-10 cm using grid sampling (20 m×20 m) in a 25 hm2 (500 m×500 m) dynamic monitoring plot. We further analyzed the spatial variability of soil medium- and micro-elements and their drivers, with classic statistics analysis and geo-statistics analysis. The results showed that the average contents of exchangeable Ca and Mg and available Fe, Mn, Cu, Zn, and B were 7870, 1490, 30.24, 149.12, 1.77, 13.54, and 0.65 mg·kg-1, respectively. The coefficient of variation of the nutrients ranged from 34.5% to 68.8%, showing a medium degree of their spatial variation. The coefficient of determination of the best-fit semi-variogram models of each nutrient was higher than 0.90, except for available Zn (0.78), indicating a strong predictive power for the spatial variation of the nutrients. The nugget coefficients for all the nutrients were less than 50%, showing a moderate spatial correlation, and the structural factors played a pivotal role. The spatially autocorrelated variation was within the range of 60.3-485.1 m, among which available Zn showed the lowest range and the deepest fragmentation degree. The spatial distribution of exchangeable Ca, Mg, and available B were consistent, with contents in the depression being significantly lower than that in other habitats. The contents of available Fe, Mn, and Cu declined with the increases of altitude and were significantly lower on the hilltop than in other habitats. The spatial variation of soil medium- and micro-elements was closely related to topographic factors in karst forest. Elevation, slope, soil thickness, and rock exposure rate were the primary drivers of spatial variation of soil elements and need to be considered in soil nutrient management of karst forestlands.
Subject(s)
Ecosystem , Soil , Soil/chemistry , Forests , ChinaABSTRACT
In modern geochemistry, phosphorus (P) is considered synonymous with phosphate (Pi) because Pi controls the growth of organisms as a limiting nutrient in many ecosystems. The researchers therefore realised that a complete P cycle is essential. Limited by thermodynamic barriers, P was long believed to be incapable of redox reactions, and the role of the redox cycle of reduced P in the global P cycling system was thus not ascertained. Nevertheless, the phosphite (Phi) form of P is widely present in various environments and participates in the global P redox cycle. Herein, global quantitative evidences of Phi are enumerated and the early origin and modern biotic/abiotic sources of Phi are elaborated. Further, the Phi-based redox pathway for P reduction is analysed and global multienvironmental Phi redox cycle processes are proposed on the basis of this pathway. The possible role of Phi in controlling algae in eutrophic lakes and its ecological benefits to plants are proposed. In this manner, the important role of Phi in the P redox cycle and global P cycle is systematically and comprehensively identified and confirmed. This work will provide scientific guidance for the future production and use of Phi products and arouse attention and interest on clarifying the role of Phi in the environmental phosphorus cycle.
ABSTRACT
Intestinal flora regulation is an effective method to intervene and treat diseases associated with microbiome imbalance. In addition to conventional probiotic supplement, phage delivery has recently exhibited great prospect in modifying gut flora composition and regulating certain gene expression of gut bacteria. However, the protein structure of phage is vulnerable to external factors during storage and delivery, which leads to the loss of infection ability and flora regulation function. Encapsulation strategy provides an effective solution for improving phage stability and precisely controlling delivery dosage. Different functional materials including enzyme-responsive and pH-responsive polymers have been used to construct encapsulation carriers to protect phages from harsh conditions and release them in the colon. Meanwhile, diverse carriers showed different characteristics in structure and function, which influenced their protective effect and delivery efficiency. This review systematically summarizes recent research progress on the phage encapsulation and delivery, with an emphasis on function properties of carrier systems in the protection effect and colon-targeted delivery. The present review may provide a theoretical reference for the encapsulation and delivery of phage as microbiota modulator, so as to expedite the development of functional material and delivery carrier, as well as the advances in practical application of intestinal flora regulation.
Subject(s)
Bacteriophages , Gastrointestinal Microbiome , Pharmaceutical Preparations , Proteins , BacteriaABSTRACT
Tree mortality is an important ecological process in forests. It is crucial to understand how tree mortality affects spatial patterns and interspecific associations for revealing the mechanisms of tree mortality and community dynamics. We employed the correlation method of spatial point pattern analysis to analyse the variations in spatial patterns and interspecific relations before and after mortality using data obtained from two surveys of a 25 hm2 plot in the Mulun National Natural Reserve, China. The results showed that most species had an aggregated distribution both pre- and post-mortality. The proportion of species with aggregated distribution reduced slightly post-mortality compared with that for pre-mortality. Increases in the number of species with random distribution at small scale indicated that tree death was not random. At the species level, there were significant positive associations between dead and live trees of the 13 common species at different levels of 0-30 m range, suggesting weak intraspecific and interspecific competition among dominant species. Pre- and post-mortality interspecific associations were mostly positive, which remained stable during the period of two surveys for most species, indicating that the community had reached a rather stable stage. Following tree mortality, the number of species with positive associations increased at 1-30 m scales, whereas the number of species with negative and no associations decreased at most scales. These results indicated that the pressure of interspecific competition was relieved to some extent after individual death.
Subject(s)
Ecosystem , Trees , Humans , Forests , China , Spatial AnalysisABSTRACT
Objective To explore the prognostic value of high-sensitivity cardiac troponin T (hs-cTnT) in predicting mortality within 28 days among sepsis patients,and to investigate the risk factors of hs-cTnT elevation. Methods The clinical and laboratory data of patients with sepsis or septic shock who were hospitalized at the Second Affiliated Hospital of Chongqing Medical University from December 2017 to September 2021 were collected and retrospectively analyzed.The patients were assigned into a hs-cTnT elevated group (hs-cTnT>0.1 ng/ml) and a hs-cTnT non-elevated group (hs-cTnT≤0.1 ng/ml).The prognosis was compared between the two groups and the risk factors of hs-cTnT elevation were determined. Results A total of 225 patients were included in this study,including 49 in hs-cTnT elevated group (21.8%) and 176 in hs-cTnT non-elevated group (78.2%).The receiver operating characteristic curve showed that maximum hs-cTnT had predictive value for death within 28 days (P<0.001).The maximum hs-cTnT showed the area under the receiver operating characteristic curve of 0.767 (95%CI=0.699-0.835),the sensitivity of 62.5%,and the specificity of 79.9%.The mortality within 28 days of hs-cTnT elevated group was higher than that of hs-cTnT non-elevated group (53.1% vs. 17.0%, χ2=26.595, P<0.001).Multivariate Logistic regression analysis revealed that the independent predictors of hs-cTnT elevation were age ≥75.5 years (OR=5.990, 95%CI=2.143-16.742, P=0.001),lactate ≥4.05 mmol/L (OR=4.982,95%CI=1.433-17.315,P=0.012),oxygenation index ≤169.15 mmHg (OR=5.052, 95%CI=1.888-13.514, P=0.001),B-type brain natriuretic peptide precursor ≥6 687.0 pg/ml (OR=5.991, 95%CI=2.226-16.128, P<0.001),fibrinogen ≤2.87 g/L (OR=3.325,95%CI=1.175-9.404, P=0.024),and International Society on Thrombosis and Haemostasis overt disseminated intravascular coagulation score ≥5.5 (OR=7.631, 95%CI=1.157-50.338, P=0.035). Conclusions hs-cTnT showed good performance in predicting mortality within 28 days among the patients with sepsis.Coagulation disorder,microthrombus formation,and myocardial oxygen supply-demand mismatch may be the risk factors of myocardial injury in sepsis.
Subject(s)
Sepsis , Troponin T , Aged , Humans , Natriuretic Peptide, Brain , Prognosis , Retrospective Studies , Risk Factors , Sepsis/diagnosisABSTRACT
As a significant part of outdoor built-environment, public open spaces are closely associated with people's daily lives. Studies of outdoor behavior in these spaces can shed light on users' environmental perceptions and contribute to the promotion of physiological and psychological health. Many recent studies are case studies focused where observations, surveys and interviews have been conducted to understand the factors influencing people's behavior on one or few sites or city environments. There have been few reviews related to this topic, and none have been based on the systematic understanding of influencing factors. This paper presents a systematic review of interactions between behavior and the built environment in public open spaces, and highlights the impacts of diverse and objective influencing factors. Followed the rules of PRISMA method (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), 109 papers published in 2000-2021 were selected and reviewed. The distribution of the studied interactions is analyzed, and the impacts of four distinct factors: personal background, location and context, environmental component, and climate stimuli, are extracted, categorized, and specified. Moreover, outdoor health benefits are discussed based on which, crucial factors that require emphasis after the outbreak of COVID-19 are identified. Throughout this paper, behavioral influencing processes, including objective influencing factors, subjective feedback, and the relationships involved, are considered to provide a comprehensive picture. With the robust classification of existing factors, architects, urban designers, policy makers and fellow researches could be easier to get a more comprehensive trend from the past. This paper also provides guidance for future research, especially given that COVID-19 has created huge changes to outdoor needs and customary behavior. Systematic Review Registration: http://www.prisma-statement.org/.
Subject(s)
Built Environment , Social Behavior , COVID-19/epidemiology , Humans , Mental HealthABSTRACT
Purpose: The purpose of our study was to explore the prognostic value of complete blood count and myocardial markers combination with Sequential Organ Failure Assessment (SOFA) score in predicting the 28-day mortality among sepsis patients. Patients and methods: A retrospective observational cohort study was performed. Three hundred and nineteen sepsis patients who were hospitalized at the Second Affiliated Hospital of Chongqing Medical University, China, from January 2019 to September 2021 were included. The clinical and laboratory data, the Acute Physiological and Chronic Health Evaluation II (APACHE II) score and SOFA score at the time of the initial sepsis diagnosis were collected, and the predictive values of the single and combination variables for 28-day mortality were compared. Results: The derivation cohort consisted of 221 patients and included 59 (26.7%) died. The area under the curve (AUC) [95% confidence interval (CI)] of RDW and cTnT were 0.735 (0.663-0.807) and 0.753 (0.678-0.827) for mortality, and the cut-off value were 14.05% and 0.039 ng/mL, respectively. The combination of RDW, cTnT and the SOFA score showed a better performance for the prediction of mortality, and the AUC was significantly higher than that of the SOFA score (0.791 vs 0.726, DeLong test: P=0.032). Multivariate Cox analysis identified that the combination of RDW, cTnT and the SOFA score (HR=6.133, P=0.004) and APACHE II score (HR=1.093, P<0.001) were independent detrimental factors for 28-day mortality. The validation cohort consisted of 98 patients and included 23 (23.5%) died. Similarly, the AUC of the RDW, cTnT and the SOFA score combination is significantly higher than that of the SOFA score (0.821 vs 0.739, DeLong test: P=0.035). Conclusion: RDW and cTnT showed good performance in predicting 28-day mortality rates among patients with sepsis. Combined RDW and cTnT with the SOFA score can significantly improve the predictive value of SOFA score for the prognosis of sepsis.
ABSTRACT
The combination of adsorption-photocatalysis and advanced oxidation processes (AOP) based on sulfate (SO4â¢-) for the treatment of organic pollution has the advantages of a high degradation rate, affordability, and an absence of secondary pollution. This study combined amphiphilic super-crosslinked porous cyclodextrin resin (PBCD-B-D), bismuth oxybromide (BiOBr), a composite material with dual functions of adsorption and photocatalysis, and AOP based on SO4â¢- for the treatment of Acid Orange 7 (AO7) in water. The combination of BiOBr/PBCD-B-D (BOP-24) with peroxymonosulfate (PMS) showed an optimal adsorption-photocatalytic effect. Compared to the 24% PBCD-B-D (BOP-24)/visible light system, the degradation efficiency of BOP-24/PMS system for AO7 is increased from 64.1% to 99.2% within shorter time (â¼60 min). Moreover, the BOP-24/PMS system showed a wide range of pH application (pH = 3-11). The addition of Cl-, SO42-, and NO3- promoted the photodegradation of AO7, whereas the addition of CO32- did not. The free radical capture experiments of the BOP-24/PMS AO7 degradation system showed that â¢O2-, h+, â¢OH, and SO4â¢- are reactive species. The proposed BOP-24 system used adsorption and a unique cavity structure to enrich AO7 near the active site, thereby reducing the path for PMS activation. PMS also acted as an electron (e-) acceptor to promote the transfer of part of e- to PMS, thereby further improving the efficiency of carrier separation. The proposed system is an effective method to improve the degradation of pollutants and broadens the range of application of SO4â¢--based AOP technology.
Subject(s)
Cyclodextrins , Environmental Pollutants , Water Pollutants, Chemical , Bismuth , Cellulose , Light , Oxidation-Reduction , Peroxides , Water , Water Pollutants, Chemical/analysisABSTRACT
BACKGROUND: The effectiveness of adjunctive corticosteroid use in patients with coronavirus disease 2019 (COVID-19) remains inconclusive. AIM: To investigate the effectiveness of adjunctive corticosteroid therapy in patients with severe COVID-19. METHODS: We conducted a retrospective analysis of the difference in several outcomes between patients with severe COVID-19 who received corticosteroid therapy (the corticosteroid group) and patients with severe COVID-19 who did not receive corticosteroid therapy (the non-corticosteroid group). RESULTS: Seventy-five patients were included in this study. Of these, 47 patients were in the corticosteroid group and 28 patients were in the non-corticosteroid group. There were no differences between the two groups in the total length of hospital stay, the length of intensive care unit stay, high-flow oxygen days, non-invasive ventilator days, invasive ventilation days, and mortality rate. Total lesion volume ratio, consolidation volume ratio and ground-glass opacity volume ratio in the corticosteroid group decreased significantly on day 14, while those in the non-corticosteroid group did not show a significant decrease. CONCLUSION: Our results show that adjunctive corticosteroid use did not significantly improve clinical outcomes in severe COVID-19 patients, but might promote the absorption of pulmonary lesions. Larger multicenter randomized controlled studies may be needed to confirm this.
ABSTRACT
Arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) associations are critical for host-tree performance. However, how mycorrhizal associations correlate with the latitudinal tree beta-diversity remains untested. Using a global dataset of 45 forest plots representing 2,804,270 trees across 3840 species, we test how AM and EcM trees contribute to total beta-diversity and its components (turnover and nestedness) of all trees. We find AM rather than EcM trees predominantly contribute to decreasing total beta-diversity and turnover and increasing nestedness with increasing latitude, probably because wide distributions of EcM trees do not generate strong compositional differences among localities. Environmental variables, especially temperature and precipitation, are strongly correlated with beta-diversity patterns for both AM trees and all trees rather than EcM trees. Results support our hypotheses that latitudinal beta-diversity patterns and environmental effects on these patterns are highly dependent on mycorrhizal types. Our findings highlight the importance of AM-dominated forests for conserving global forest biodiversity.
Subject(s)
Biodiversity , Forests , Mycorrhizae/physiology , Trees/physiology , Host Microbial Interactions/physiology , Plant Dispersal , Soil Microbiology , Trees/microbiologyABSTRACT
The decline in species richness at higher latitudes is among the most fundamental patterns in ecology. Whether changes in species composition across space (beta-diversity) contribute to this gradient of overall species richness (gamma-diversity) remains hotly debated. Previous studies that failed to resolve the issue suffered from a well-known tendency for small samples in areas with high gamma-diversity to have inflated measures of beta-diversity. Here, we provide a novel analytical test, using beta-diversity metrics that correct the gamma-diversity and sampling biases, to compare beta-diversity and species packing across a latitudinal gradient in tree species richness of 21 large forest plots along a large environmental gradient in East Asia. We demonstrate that after accounting for topography and correcting the gamma-diversity bias, tropical forests still have higher beta-diversity than temperate analogues. This suggests that beta-diversity contributes to the latitudinal species richness gradient as a component of gamma-diversity. Moreover, both niche specialization and niche marginality (a measure of niche spacing along an environmental gradient) also increase towards the equator, after controlling for the effect of topographical heterogeneity. This supports the joint importance of tighter species packing and larger niche space in tropical forests while also demonstrating the importance of local processes in controlling beta-diversity.
Subject(s)
Biodiversity , Trees , Ecology , Asia, EasternABSTRACT
BACKGROUND: Since the start of the COVID-19 pandemic, there have been over 2 million deaths globally. Acute respiratory distress syndrome (ARDS) may be the main cause of death. OBJECTIVE: This study aimed to describe the clinical features, outcomes, and ARDS characteristics of patients with COVID-19 admitted to the intensive care unit (ICU) in Chongqing, China. METHODS: The epidemiology of COVID-19 from January 21, 2020, to March 15, 2020, in Chongqing, China, was analyzed retrospectively, and 75 ICU patients from two hospitals were included in this study. On day 1, 56 patients with ARDS were selected for subgroup analysis, and a modified Poisson regression was performed to identify predictors for the early improvement of ARDS (eiARDS). RESULTS: Chongqing reported a 5.3% case fatality rate for the 75 ICU patients. The median age of these patients was 57 (IQR 25-75) years, and no bias was present in the sex ratio. A total of 93% (n=70) of patients developed ARDS during ICU stay, and more than half had moderate ARDS. However, most patients (n=41, 55%) underwent high-flow nasal cannula oxygen therapy, but not mechanical ventilation. Nearly one-third of patients with ARDS improved (arterial blood oxygen partial pressure/oxygen concentration >300 mm Hg) in 1 week, which was defined as eiARDS. Patients with eiARDS had a higher survival rate and a shorter length of ICU stay than those without eiARDS. Age (<55 years) was the only variable independently associated with eiARDS, with a risk ratio of 2.67 (95% CI 1.17-6.08). CONCLUSIONS: A new subphenotype of ARDS-eiARDS-in patients with COVID-19 was identified. As clinical outcomes differ, the stratified management of patients based on eiARDS or age is highly recommended.
Subject(s)
COVID-19/complications , Respiratory Distress Syndrome/therapy , Respiratory Distress Syndrome/virology , Adult , Aged , COVID-19/mortality , China/epidemiology , Female , Humans , Intensive Care Units , Male , Middle Aged , Respiratory Distress Syndrome/mortality , Retrospective Studies , Treatment OutcomeABSTRACT
Soil bacteria participate in nutrient cycling above and below ground to promote ecosystem stability and health. However, the relationship of soil bacteria and environmental factors following the Grain for Green (GfG) program remains poorly understood in southwest China. Soil samples were collected from seven Grain for Green sites that had been revegetated for 15 years. Four of these sites were afforested with a different tree species: Zenia insignis (ZI), Toona sinensis (TS), Castanea mollissima (CM), and Citrus reticulate (CR). One site was revegetated with Zenia insignis and Guimu-1 elephant grass (ZG), and one with only Guimu-1 elephant grass (GM). The remaining site, abandoned cropland (AC), was left to regenerate naturally. Here, we used Illumina sequencing of 16S rRNA genes to explore how the Grain for Green project affected soil bacterial community. We found that Actinobacteria, Proteobacteria, Chloroflexi, and Acidobacteria were the dominant phyla in these soils. The dominant genera at each revegetation site were also different. The CM, ZI, TS, and AC sites were dominated by Micromonospora, ZG was dominated by Streptomyces, and CR and GM were dominated by Subgroup 6. The bacterial structure was most similar in AC and TS. Correlation analysis showed that the ratio of C:P had positive effects on KD4-96, Intrasporangiaceae, and Gaiella. The ratio of soil N:P was significantly positively correlated with Cupriavidus and Kribbella. The combination of planting Zenia insignis and Guimu-1 elephant grass had the best edaphic benefits, and the approach of planting Citrus reticulate and Toona sinensis needs to be improved. Redundancy analysis (RDA) revealed that plant Simpson index, and soil N:P contributed to 16 and 15.7% of the total variations in the soil bacterial community composition, respectively. Our results suggested that plant diversity (Simpson index) and soil stoichiometric ratio (N:P) were the important factors affecting the bacterial community, and phosphorus was the limiting factor of the bacterial community in the Grain for Green karst region. In the future, revegetation should be accompanied with phosphorus fertilizer and polycultures should be considered.