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Secondary lung injury after SCI is a major cause of patient mortality, with apoptosis playing a key role. This study aimed to explore the impact of treadmill training and miR145-5p on the MAPK/Erk signaling pathway and apoptosis in rats with complete SCI. SD rats were used to establish T10 segmental complete SCI models and underwent treadmill training 3, 7, or 14 days postinjury. Various techniques including arterial blood gas analysis, lung wet/dry weight ratio, HE staining, immunofluorescence staining, immunohistochemical staining, qRT-PCR, and Western blotting were employed to assess alterations in lung function and the expression levels of crucial apoptosis-related factors. In order to elucidate the specific mechanism, the impact of miR145-5p on the MAPK/Erk pathway and its role in apoptosis in lung cells were confirmed through miR145-5p overexpression and knockdown experiments. Following spinal cord injury (SCI), an increase in apoptosis, activation of the MAPK/Erk pathway, and impairment of lung function were observed in SCI rats. Conversely, treadmill training resulted in a reduction in alveolar cell apoptosis, suppression of the MAPK/Erk pathway, and enhancement of lung function. The gene MAP3K3 was identified as a target of miR145-5p. The influence of miR145-5p on the MAPK/Erk pathway and its impact on apoptosis in alveolar cells were confirmed through the manipulation of miR145-5p expression levels. The upregulation of miR145-5p in spinal cord injury (SCI) rats led to a reduction in MAP3K3 protein expression within lung tissues, thereby inhibiting the MAPK/Erk signaling pathway and decreasing apoptosis. Contrarily, rats with miR145-5p knockdown undergoing treadmill training exhibited an increase in miR145-5p expression levels, resulting in the inhibition of MAP3K3 protein expression in lung tissues, suppression of the MAPK/Erk pathway, and mitigation of lung cell apoptosis. Ultimately, the findings suggest that treadmill training may attenuate apoptosis in lung cells post-spinal cord injury by modulating the MAP3K3 protein through miR145-5p to regulate the MAPK/Erk signaling pathway. [ABSTRACT FROM AUTHOR]

Aims: Although plant–microbial interactions are essential to sustain terrestrial ecosystem functions, root–microbial interactions remain poorly understood. Therefore, understanding how functional trait diversity of fine roots mediates soil microbial diversity and composition provides insightful information to maintain forest ecosystem functions. Methods: A total of 87 plots with 1–12 tree species richness gradient in three subtropical secondary forests were selected. Functional trait diversity (functional dispersion, FDis, and community-weighted mean, CWM) of fine roots was quantified. Soil microbial diversity and community composition were analyzed by high-throughput Illumina sequencing. Results: Bacterial and fungal richness was primarily predicted by CWM of root diameter (CWM_diam) in the humus horizon, but by FDis of specific root length (FDis_SRL) in the mineral horizon. Microbial community composition in two soil horizons increased with FDis_SRL, including the abundance of copiotrophic bacteria (r-strategists, e.g., Proteobacteria, Actinobacteria), Chloroflexi, saprotrophs and pathogens. FDis_SRL was also indirectly mediated microbial richness and composition via decreasing carbon:nitrogen ratio and increasing pH, total nitrogen, total and available phosphorus contents. Conclusions: Overall, functional trait diversity of fine roots plays a pivotal role in mediating soil microbial richness and community composition in subtropical secondary forests. These results deepen our understanding of the important role of plant–microbial interactions in terrestrial biogeochemical processes. [ABSTRACT FROM AUTHOR]

Shrubbery and young plantations, with a large number of tree species, take up a broad area in subtropical Chinese forests and contribute a significant part to forest biomass and carbon (C) stocks. However, the biomass and C stocks of shrubbery and young plantations were generally underestimated or excluded in forest biomass calculations due to the scarce of standard equations for estimating biomass. The aim of this study was to develop appropriate regression equations for biomass estimation of shrubbery and young plantations. A total of 108 individuals of 15 most widespread shrub and young tree species were sampled by destructive harvesting, and the dry weight of each component of trees, i.e., foliage, branch, stem and root were obtained. The dry biomass of each component was correlated with plant height (H), basal diameter of stem (D), crown area (CA) and their composite variables D2H and CV (CA × H) by using seemingly uncorrelated regression, and the best fitted model was chosen according to the determination coefficient (R2), root mean squared error (RMSE), Akaike's information criterion (AIC) and percent relative standard errors (PRSE) less than 25%. In the species-specific equations, H, D or D2H were used as the appropriate independent variables in most of the equations, and only a few of them were CA or CV. In the multiple species equations, H was an important variable to predict the biomass, but the predictors of biomass equation for different functional groups or life forms were different due to diversity of external morphology. The species-specific equations had low biases, while the general equations for functional groups and life forms showed comparable biases, and the general equations for all species had the highest prediction biases. Therefore, general equations for functional groups or life forms are recommended to estimate biomass for species without species-specific allometric equations. [ABSTRACT FROM AUTHOR]

The process of rapid urbanization in China has led to various impacts on the urban ecological environment and one of these significant effects is the urban heat island (UHI). Pursuing the construction of a ecological city is recognized as an important direction to relieve the contradictions between environmental protection and city development. Yet how the landcape configuation and composition in such city development influences the UHI has not been well understood. This paper attempted to evaluate the spatial patterning of land surface temperature (LST) and to discuss the effects of source and sink landscape patterns upon LST in a smart city demonstrated at the local level in China. The results revealed that the UHI was spatially associated with the land use changes driven by rapid urbanization and gradually declines along the urban–rural gradient. When the urban–rural gradient reached the range of 7.5 to 8.75 km from the city center, there exhibited a tipping point where the combinative effects of source and sink landscapes on UHI significantly decreased. Through exploring the impact of source-sink landscape area ratio on UHI, we also found a tipping point that when source-sink area ratio in a patch was smaller than the golden separation value (1.30), UHI effect was almost mitigated because the warming effect of source area would be weaker than the cooling effect of sink area. Overall, this study highlights that controlling the optimal area ratio of source-sink landscape are very important strategy for mitigating the UHI effect during urban development and planning. [ABSTRACT FROM AUTHOR]

Background: Forest ecosystems play an important role in carbon sequestration, climate change mitigation, and achieving China's target to become carbon (C) neutral by 2060. However, changes in C storage and net primary production (NPP) in natural secondary forests stemming from tree growth and future climate change have not yet been investigated in subtropical areas in China. Here, we used data from 290 inventory plots in four secondary forests [evergreen broad-leaved forest (EBF), deciduous and evergreen broad-leaved mixed forest (DEF), deciduous broad-leaved forest (DBF), and coniferous and broad-leaved mixed forest (CDF)] at different restoration stages and run a hybrid model (TRIPLEX 1.6) to predict changes in stand carbon storage and NPP under two future climate change scenarios (RCP4.5 and RCP8.5). Results: The runs of the hybrid model calibrated and validated by using the data from the inventory plots suggest significant increase in the carbon storage by 2060 under the current climate conditions, and even higher increase under the RCP4.5 and RCP8.5 climate change scenarios. In contrast to the carbon storage, the simulated EBF and DEF NPP declines slightly over the period from 2014 to 2060. Conclusions: The obtained results lead to conclusion that proper management of China's subtropical secondary forests could be considered as one of the steps towards achieving China's target to become carbon neutral by 2060. [ABSTRACT FROM AUTHOR]

A complete characterization of genetic variation is a fundamental goal of human genome research. Long-read sequencing has improved the sensitivity of structural variant discovery. Here, we conduct the long-read sequencing-based structural variant analysis for 405 unrelated Chinese individuals, with 68 phenotypic and clinical measurements. We discover a landscape of 132,312 nonredundant structural variants, of which 45.2% are novel. The identified structural variants are of high-quality, with an estimated false discovery rate of 3.2%. The concatenated length of all the structural variants is approximately 13.2% of the human reference genome. We annotate 1,929 loss-of-function structural variants affecting the coding sequence of 1,681 genes. We discover rare deletions in HBA1/HBA2/HBB associated with anemia. Furthermore, we identify structural variants related to immunity which differentiate the northern and southern Chinese populations. Our study describes the landscape of structural variants in the Chinese population and their contribution to phenotypes and disease. Although many studies have characterized genetic variation in human populations, few have investigated structural variation and few have been in non-European populations. Here, the authors have performed long read sequencing on 405 Chinese individuals to identify structural variants and link them to phenotypes. [ABSTRACT FROM AUTHOR]

The mechanism whereby tree species richness and identity affect the production of fine roots (≤ 2 mm) in forests remains controversial. Complementarity effects (via resource partitioning and facilitation, CEs) and selection effects (that is, dominant of species with particular traits, SEs) are the two hypotheses to explain biodiversity effects on ecosystem functions. This study aimed to (1) examine how tree species diversity affects fine root production and (2) disentangle the complementarity effect and the selection effect on the relationship between biodiversity and fine root production. A total of 60 tree clusters with 15 combinations of diversity gradients consisting of 1–4 tree species (Pinus massoniana, Choerospondias axillaris, Cyclobalanopsis glauca and Lithocarpus glaber) were established in subtropical forests. The sequential soil core and ingrowth core methods were used in each cluster to measure fine root biomass and productivity. Fine root production increased with increase in tree species richness. The biodiversity effects on fine root production mostly resulted from CEs. In the nongrowing season, in most cases, the CE on biomass was positive and became stronger as richness increased, but the opposite situation was observed in the growing season. The strong positive and negative effects of the proportions of C. glauca and L. glaber in the tree clusters on fine root biomass, CEs and SEs, suggest the coordinated action of species diversity and identity in modulating biodiversity effects on belowground processes. [ABSTRACT FROM AUTHOR]

Although stand age affects biomass partitioning and allometric equations, the size of these effects and whether it is worth incorporating stand age into allometric equations, requires further attention. We sampled a total of 90 trees for 10 Chinese fir (Cunninghamia lanceolata) plantations at seven stand age classes to obtain the data of tree component biomass using destructive harvesting. A multilevel modeling approach was applied to examine how stand age effects differ among tree components and predictor variables (diameter at breast height, DBH and tree height, H). Age class-specific allometric equations and the best fitting generalized equation that included stand age as a complementary variable were developed for each tree component. Large differences in both the intercept and slope for different stand age classes indicated that stand age affected allometric models. Branch and leaves were more sensitive to the environment and were the tree components most affected by stand age. Age class-specific allometric equations fitted well (R2 > 0.65, p < 0.001) using DBH and the combined form DBH2H as predictor variables. Including stand age as a complementary variable improved the fit of generalized allometric equations. Stem, aboveground and total tree biomass predicted by the multilevel model and generalized equation were comparable to the observed data. However, the multilevel model and generalized equations had a relatively low predictive capacity for branch, leaf and root biomass. These results could improve our capacity to evaluate carbon sequestration and other ecosystem functions in plantations. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is a limiting nutrient for plant growth in most forest ecosystems. In response to P deficiency, plants alter root exudates (organic acids, phosphatases, and protons) to increase P bioavailability in soils. However, little is known about how bioavailable P pools (soluble-P, exchangeable-P, hydrolysable-P, and ligand-P extracted by CaCl2, citric acid, enzyme mixture, and HCl solution, respectively) change with stand age, especially for plantation forests. We selected a chronosequence of second-generation Chinese fir [Cunninghamia lanceolata (Lamb.) Hook., Taxodiaceae] plantations with increasing age including 3, 8–11, 16, 20, 25, 29, and 32 years. We measured total P and four bioavailable P pools in organic (O) and mineral horizons, and rhizosphere soil, as well as root exudates in the rhizosphere, litter biomass on the forest floor, and annual P uptake. Soluble-P, exchangeable-P, and ligand-P in the O horizon increased with stand age due to litter accumulation. Exchangeable-P and ligand-P in mineral soil decreased with stand age because of the increasing annual P uptake that depleted inorganic P. Exchangeable-P and ligand-P in the rhizosphere increased with stand age because the decrease in pH and citric acid concentration led to phosphate being more strongly bound to Fe and Al oxyhydroxides. Consequently, the trees' ability for P mobilization decreased with stand age, but the P recycling within the tree increased. Continuous mineralization of hydrolysable-P by acid phosphatase replenished inorganic P pools, especially in solution. The progressive incorporation of P in the biological cycle with increasing tree age indicates that extending rotation periods might be an appropriate measure to increase P supply. [ABSTRACT FROM AUTHOR]

Background: Soil and vegetation have a direct impact on the process and direction of plant community succession, and determine the structure, function, and productivity of ecosystems. However, little is known about the synergistic influence of soil physicochemical properties and vegetation features on vegetation restoration. The aim of this study was to investigate the co-evolution of soil physicochemical properties and vegetation features in the process of vegetation restoration, and to distinguish the primary and secondary relationships between soil and vegetation in their collaborative effects on promoting vegetation restoration in a subtropical area of China. Methods: Soil samples were collected to 40 cm in four distinct plant communities along a restoration gradient from herb (4–5 years), to shrub (11–12 years), to Pinus massoniana coniferous and broadleaved mixed forest (45–46 years), and to evergreen broadleaved forest (old growth forest). Measurements were taken of the soil physicochemical properties and Shannon–Wiener index (SD), diameter at breast height (DBH), height (H), and biomass. Principal component analysis, linear function analysis, and variation partitioning analysis were then performed to prioritize the relative importance of the leading factors affecting vegetation restoration. Results: Soil physicochemical properties and vegetation features showed a significant trend of improvement across the vegetation restoration gradient, reflected mainly in the high response rates of soil organic carbon (SOC) (140.76%), total nitrogen (TN) (222.48%), total phosphorus (TP) (59.54%), alkaline hydrolysis nitrogen (AN) (544.65%), available phosphorus (AP) (53.28%), species diversity (86.3%), biomass (2906.52%), DBH (128.11%), and H (596.97%). The soil properties (pH, SOC, TN, AN, and TP) and vegetation features (biomass, DBH, and H) had a clear co-evolutionary relationship over the course of restoration. The synergistic interaction between soil properties and vegetation features had the greatest effect on biomass (55.55%–72.37%), and the soil properties contributed secondarily (3.30%–31.44%). The main impact factors of biomass varied with the restoration periods. Conclusions: In the process of vegetation restoration, soil and vegetation promoted each other. Vegetation restoration was the cumulative result of changes in soil fertility and vegetation features. [ABSTRACT FROM AUTHOR]

Aims: There is evidence that different facets of biodiversity such as species richness (SR), phylogenetic diversity (PD) and functional diversity (FD) can modulate ecosystem functioning via niche-complementarity or mass-ratio effects, but the support for these hypotheses on fine root biomass remains unclear. Methods: In a tree diversity gradient in subtropical forests (ranging from 2 to 10 tree species), we identified the species identity of fine roots (≤ 2 mm in diameter) using a molecular method. This allowed computation of PD as well as trait-based FD and community-weighted means (CWM) metrics, which were then tested as predictors of fine root biomass. Results: Three metrics (SR, CWM of specific root length and PD) were positively related to root biomass. SR was the best predictor of fine root biomass and its predicting ability depended on stand density. The predicting power of CWM of specific root length varied with the soil nutrient status. Conclusions: Overall, the results supported both tested hypotheses (mass-ratio and niche-complementarity) that seem to be non-mutually exclusive. Furthermore, our findings emphasize that stand density and soil nutrient status are the important variables driving fine root biomass and trait-values. [ABSTRACT FROM AUTHOR]

Subtropical broadleaved forests play a crucial role in supporting terrestrial ecosystem functions, but little is known about their belowground soil fungal communities despite that they have central functions in C, N, and P cycles. This study investigated the structures and identified the drivers of soil fungal communities in subtropical deciduous and evergreen broadleaved forests, using high-throughput sequencing and FUNGuild for fungal identification and assignment to the trophic guild. Fungal richness was much higher in the deciduous than in the evergreen forest. Both forests were dominated by Ascomycota and Basidiomycota phyla, but saprophytic fungi were more abundant in the deciduous forest and ectomycorrhizal fungi predominated in the evergreen forest. Fungal communities had strong links to plant and soil properties. Specifically, plant diversity and litter biomass were the main aboveground drivers of fungal diversity and composition in the deciduous forest, while host effects were prominent in the evergreen forest. The belowground factors, i.e., soil pH, water content, and nutrients especially available P, were identified as the primary drivers of soil fungal communities in the broadleaved forests. Co-occurrence network analysis revealed assembly of fungal composition in broadleaved forest soils was non-random. The smaller modularity of the network in the deciduous forest reflects lower resistance to environment changes. Concluding, these results showed that plant community attributes, soil properties, and potential interactions among fungal functional guilds operate jointly on the divergence of soil fungal community assembly in the two broadleaved forest types. [ABSTRACT FROM AUTHOR]

Aims: The phylogenetic variations of fine root traits, which are related to plant growth and development as well as to physiological and ecological processes, are not fully understood. This study aimed to: (1) examine how tree species and sampling methodology affect the anatomical, morphological and nutrient traits of fine roots; and (2) determine whether phylogenetic signals affect fine root trait relationships and influence comparison of root traits between the branch order-based and diameter-based cut-off sampling categories.Methods: Fine root samples of 16 subtropical forest tree species were obtained and their anatomical, morphological and nutrient traits were studied. The phylogenetic signals of trait variations were calculated to determine trait relationships.Results: Tree species and sampling methodology significantly affected fine root traits (p < 0.05). Mean root diameters, root tissue density (RTD) and carbon-to-nitrogen ratio were the lowest in the first-order category and highest in the ≤2 mm category. The reverse pattern was found for specific root length, specific root area and nitrogen concentration. Morphological traits showed significant phylogenetic signals; however, nutrient traits did not reflect phylogenetic conservatism. Phylogenetic factors influenced correlations between traits for the first-order root economics spectrum. Root traits were multidimensional and RTD was loaded on a novel phylogenetic principal component analysis.Conclusions: Functional traits of fine roots are multidimensional for subtropical tree species and closely linked to phylogeny. Morphological traits of first order roots showed a much stronger phylogenetic signal than those of roots ≤2 mm (traditionally defined fine roots). The findings improve understanding of root trait strategies in response to environmental changes. [ABSTRACT FROM AUTHOR]

The direct neurotoxicity of HIV and neurotoxicity of combination antiretroviral therapy medications both contribute to the development of neuropathic pain. Activation of satellite glial cells (SGCs) in the dorsal root ganglia (DRG) plays a crucial role in mechanical and thermal hyperalgesia. The P2Y12 receptor expressed in SGCs of the DRG is involved in pain transmission. In this study, we explored the role of the P2Y12 receptor in neuropathic pain induced by HIV envelope glycoprotein 120 (gp120) combined with ddC (2′,3′-dideoxycytidine). A rat model of gp120+ddC-induced neuropathic pain was used. Peripheral nerve exposure to HIV-gp120+ddC increased mechanical and thermal hyperalgesia in gp120+ddC-treated model rats. The gp120+ddC treatment increased expression of P2Y12 receptor mRNA and protein in DRG SGCs. In primary cultured DRG SGCs treated with gp120+ddC, the levels of [Ca2+]i activated by the P2Y12 receptor agonist 2-(Methylthio) adenosine 5′-diphosphate trisodium salt (2-MeSADP) were significantly increased. P2Y12 receptor shRNA treatment inhibited 2-MeSADP-induced [Ca2+]i in primary cultured DRG SGCs treated with gp120+ddC. Intrathecal treatment with a shRNA against P2Y12 receptor in DRG SGCs reduced the release of pro-inflammatory cytokines, decreased phosphorylation of p38 MAPK in the DRG of gp120+ddC-treated rats. Thus, downregulating the P2Y12 receptor relieved mechanical and thermal hyperalgesia in gp120+ddC-treated rats. [ABSTRACT FROM AUTHOR]

Coarse root biomass (CRB) is an important store of carbon (C) and forest residue for renewable energy, but is often overlooked due to the lack of a simple and effective way to estimate its magnitude. In this study, we developed allometric equations for three functional groups using data from 133 tree samples, with a diameter at breast height (DBH) ranging from 2.6 to 52.0 cm. The functional groups included evergreen coniferous ( Pinus massoniana), deciduous broad-leaved ( Alniphyllum fortunei, Choerospondias axillaris, Liquidambar formosana and Quercus fabri) and evergreen broad-leaved ( Castanopsis carlesii, Cyclobalanopsis glauca, Litsea coreana and Schima superba) species. Allometric equations that related CRB to plot inventory data (e.g. DBH or tree height (H)) and their combinations significantly fitted ( P < 0.0001) for the functional groups and all tree species. The equations using DBH or DBH-H as predictor variables were the best fit ( R ≥ 0.90) and produced good predictions with little bias (less than 21%) for local sites and at regional scales. Allometric equations related to easily obtained remote sensing data (i.e. crown width (CW) and H) were also significantly fitted ( P < 0.0001, R ≥ 0.76), and predictions were close to the observed CRB, despite a high bias (larger than 98.0%). In conclusion, the use of these equations to estimate CRB is essential to the harvest process and helps to formulate new policies for managing the feedstock supply to bioenergy production in subtropical forests. [ABSTRACT FROM AUTHOR]

Aims: Our study aimed to determine whether, and to what extent, stand characteristics and topography affected spatial variations in soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) concentrations in subtropical forests. Methods: Soil samples were taken from a Choerospondias axillaris deciduous broadleaved forest and a Lithocarpus glaber-Cyclobalanopsis glauca evergreen broadleaved forest. Spatial variations in SOC, TN and TP concentrations and the factors affecting them were investigated using geostatistical analysis and stepwise linear regression, respectively. Results: The L. glaber-C. glauca forest exhibited higher coefficients of variation (CVs) of SOC (35 %) and TN (34 %) concentrations than the C. axillaris forest (27 % for SOC and 21 % for TN), but the CV of TP concentration in the L. glaber-C. glauca forest (17 %) was lower than that in the C. axillaris forest (24 %). Stand characteristics contributed the most to spatial variations in SOC and TP, while soil texture made the greatest contribution to variations in TN. Topography contributed the least to variations in SOC, TN and TP. Conclusions: Stand characteristics, together with topography and soil texture, contributed to spatial variations in SOC, TN and TP concentrations. The contributions of stand characteristics differed in SOC, TN and TP due to their different cycling characteristics. [ABSTRACT FROM AUTHOR]

Chinese subtropical forests contain a diversity of tree species and exhibit a high carbon (C) sequestration capacity, but biomass and C stock assessments in subtropical secondary forests remain uncertain because of a limited availability of allometric equations and an uncertain applicability of existing allometric equations that have not been tested for these forests. We developed allometric equations for important coniferous ( Pinus massoniana), deciduous broadleaved ( Alniphyllum fortunei, Choerospondias axillaris, Liquidambar formosana) and evergreen broadleaved ( Cyclobalanopsis glauca, Litsea rotundifolia, Schima superba) species. A total of 70 trees (10 trees for each species) with diameters at breast height ( D) ranging from 2.6 to 50.9 cm were destructively harvested and dissected into tree components (stem, branch, leaf and coarse root). Species-specific equations using D alone as the predictor variable fitted the data well ( p < 0.0053 and R > 0.72) for each tree component. Including height ( H) in the form of D H only improved the regression fit for A. fortunei and L. rotundifolia. The relationships of branch, leaf and root biomass against D varied among tree species. General equations for functional groups and all species combined showed comparable bias for stem, aboveground and total tree biomass to species-specific equations. We recommend the general equations of multiple species to estimate forest biomass at regional scales and also to estimate stem, aboveground and total tree biomass for each species when species-specific allometric equations are not available at a given site. For branch, leaf and root biomass, species-specific equations are preferred, even though this requires biomass data for additional tree species. [ABSTRACT FROM AUTHOR]

Due to the authors' carelessness, we mistakenly used similar images between the Fig. 1b on the expression of P2Y12 protein (upper) and Fig. 5a on the expression of phospho-p38 MAPK (p-p38 MAPK) protein (upper). [ABSTRACT FROM AUTHOR]