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The ultrahigh‐pressure (UHP) eclogites from the Kaghan Valley in Pakistan, which formed by the deep subduction of the Indian plate beneath the Asian plate in the Eocene, contain complex metamorphic vein systems (including both isolated veins and vein networks), with mineral assemblages of epidote + quartz + kyanite + phengite ± omphacite ± garnet. The investigations on the Kaghan UHP eclogite‐vein systems provide important insights into the mechanism and timing of metamorphic dehydration, fluid flow, and fluid–rock interaction in the deeply subducted Indian continental slab as well as the chemical characteristics of slab‐derived, aqueous fluids. Abundant lawsonite pseudomorphs, characterized by prismatic aggregates of epidote, kyanite, and quartz porphyroblasts, are first recognized in the Kaghan eclogites. This observation, in combination with the occurrence of coesite pseudomorphs in epidote porphyroblasts as well as the coexistence of epidote and coesite in the eclogite zircon, indicates the previous existence of UHP lawsonite in these eclogites. Petrological studies and phase equilibrium modelling reveal clockwise P–T trajectories for the Kaghan eclogites that are featured by prograde vectors in lawsonite‐stability regions with peak conditions of 3.0–3.4 GPa/650–690°C, followed by isothermal decompression and lawsonite breakdown under UHP conditions during the initial exhumation stage. The results of metamorphic evolution, together with in situ epidote and bulk Sr isotopic analyses, indicate that the fluids responsible for vein systems are most likely derived from the breakdown of UHP lawsonite in the eclogites. SIMS U–Pb dating of metamorphic zircons from the eclogites, integrated with the Raman analysis of inclusions in zircons, indicates that the UHP dehydration of eclogites occurred at 46.4 ± 1.2 and 46.8 ± 0.9 Ma. Analyses of hydrothermal zircons from the veins yielded slightly younger ages of 44.7 ± 1.0 and 44.9 ± 1.4 Ma, which represent the timing of fluid flow and/or vein crystallization during exhumation of the UHP rocks. Mass‐balance calculation results, in combination with the vein compositions, show that the fluid flow and fluid‐eclogite interaction led to the transfer of Si, Al, Ca, K, and incompatible trace elements from the eclogites into the fluids, from which the vein systems crystallized. This study indicates cold deep subduction of Indian continental crust along low geothermal gradients (6–7°C/km). The UHP fluid liberation and channelized fluid flow occurred during the initial exhumation of the cold Indian slab and are expected to induce the transfer of H2O and incompatible trace elements from the Indian slab to the Asian lithosphere, which potentially contributes to the formation of post‐collisional magmas. Moreover, we suggest that metamorphic vein systems in UHP lawsonite eclogites offer important constraints on the occurrence and timing of fast slab exhumation in continental subduction‐collision zones. [ABSTRACT FROM AUTHOR]

Grassland and other herbaceous communities cover significant portions of Earth's terrestrial surface and provide many critical services, such as carbon sequestration, wildlife habitat, and food production. Forecasts of global change impacts on these services will require predictive tools, such as process‐based dynamic vegetation models. Yet, model representation of herbaceous communities and ecosystems lags substantially behind that of tree communities and forests. The limited representation of herbaceous communities within models arises from two important knowledge gaps: first, our empirical understanding of the principles governing herbaceous vegetation dynamics is either incomplete or does not provide mechanistic information necessary to drive herbaceous community processes with models; second, current model structure and parameterization of grass and other herbaceous plant functional types limits the ability of models to predict outcomes of competition and growth for herbaceous vegetation. In this review, we provide direction for addressing these gaps by: (1) presenting a brief history of how vegetation dynamics have been developed and incorporated into earth system models, (2) reporting on a model simulation activity to evaluate current model capability to represent herbaceous vegetation dynamics and ecosystem function, and (3) detailing several ecological properties and phenomena that should be a focus for both empiricists and modelers to improve representation of herbaceous vegetation in models. Together, empiricists and modelers can improve representation of herbaceous ecosystem processes within models. In so doing, we will greatly enhance our ability to forecast future states of the earth system, which is of high importance given the rapid rate of environmental change on our planet. [ABSTRACT FROM AUTHOR]

The parameterization of key photosynthesis parameters is one of the key uncertain sources in modeling ecosystem gross primary productivity (GPP). Solar‐induced chlorophyll fluorescence (SIF) offers a good proxy for GPP since it marks the actual process of photosynthesis; while machine learning (ML) provides a robust approach to model the GPP‐SIF relationship. Here, we trained the boosted regressing tree (BRT) and the Random Forest ML models with Greenhouse Gases Observing Satellite SIF data and in situ GPP observations from 49 eddy covariance towers. These trained ML GPP‐SIF models were fed into the Energy Exascale Earth System Model (E3SM) Land Model (ELM) to generate ELM‐simulated global SIF estimates, which were then benchmarked against satellite SIF observations with a surrogate modeling approach. Our results indicated good modeling performance of the ML‐based GPP‐SIF relationship. The ELM model when fed with the ML GPP‐SIF models also can well predict the spatial‐temporal variations in SIF. We also found high model accuracy for the surrogate modeling. Model parameter sensitivity analysis suggested that the fraction of leaf nitrogen in RuBisCO (flnr) is the most sensitive parameter to the SIF; other sensitive parameters include the Ball‐Berry stomatal conductance slope (mbbopt) and the vcmax entropy (vcmaxse). The posterior uncertainty in simulated GPP was greatly reduced after benchmarking, and the model produced improved spatial patterns of mean GPP relative to FLUXCOM GPP. Our integrated approach provides a new avenue for improving land models and using remote‐sensing SIF, which can be further improved in the future with more ground‐ and satellite‐based observations. Plain Language Summary: Model estimation of photosynthesis product, that is, gross primary productivity (GPP), is a challenging but vital task. One of the keys is to find better values for key parameters. This parameter searching process requires good proxies for GPP that can be widely available across space and time, good statistical methods to relate proxies to GPP and to make best estimations that reduce the gaps between modeled results and observations. Here, we designed a new method that use solar‐induced chlorophyll fluorescence (SIF, a good proxy for photosynthesis) as a key input, and employ machine learning (a robust way to relate SIF and GPP) and surrogate modeling (a good method for finding the best parameters), to improve the photosynthesis parameterization in the Energy Exascale Earth System Model (E3SM) Land Model (ELM), a state‐of‐the‐art terrestrial biosphere model. Our results demonstrate that this new integrated approach has great potential for improving the parameterization of key photosynthesis parameters in land models. Key Points: We built a unique method to improve gross primary productivity (GPP) modeling in land modelsThis method integrates solar‐induced chlorophyll fluorescence observations, machine learning, and surrogate modelingThe method reduced posterior uncertainties in simulated GPP and improved the modeling of its spatial patterns [ABSTRACT FROM AUTHOR]

Gradient and scale are two key concepts in ecology and evolution that are closely related but inherently distinct. While scale commonly refers to the dimensional space of a specific ecological/evolutionary (eco–evo) issue, gradient measures the range of a given variable. Gradient and scale can jointly and interactively influence eco–evo patterns. Extensive previous research investigated how changing scales may affect the observation and interpretation of eco–evo patterns; however, relatively little attention has been paid to the role of changing gradients. Here, synthesizing recent research progress, we suggest that the role of scale in the emergence of ecological patterns should be evaluated in conjunction with considering the underlying environmental gradients. This is important because, in most studies, the range of the gradient is often part of its full potential range. The difference between sampled (partial) versus potential (full) environmental gradients may profoundly impact observed eco–evo patterns and alter scale–gradient relationships. Based on observations from both field and experimental studies, we illustrate the underlying features of gradients and how they may affect observed patterns, along with the linkages of these features to scales. Since sampled gradients often do not cover their full potential ranges, we discuss how the breadth and the starting and ending positions of key gradients may affect research design and data interpretation. We then outline potential approaches and related perspectives to better integrate gradient with scale in future studies. [ABSTRACT FROM AUTHOR]

Simple Summary: Based on the investigation of altitudinal distribution data with identification by using both molecular and morphological classifications of Pyraustinae and Spilomelinae, this paper determines the altitudinal gradient pattern for these two subfamilies on the north slope of Mount Taibai of the Qinling Mountains, and provides a test of the universality of Rapoport's rule in Lepidoptera by using four methods. Our results show that alpha diversity of Pyraustinae and Spilomelinae both decrease with rising altitude. By contrast, the species distribution ranges increase with rising altitude. Three of the four methods used to test Rapoport's rule yielded positive results, while Rohde's results show a unimodal distribution model and do not support Rapoport's rule. Rapoport's rule proposes that a species' range size increases with the increase in a gradient (such as latitude, altitude or water depth). However, altitudinal distributions and Rapoport's rule have rarely been tested for Asian Lepidoptera. Pyraustinae and Spilomelinae (Lepidoptera: Crambidae) are extremely diverse in temperate Asia, including on Mount Taibai, which is considered a hotspot area for studying the vertical distribution patterns of insect species. Based on the investigation of altitudinal distribution data with identification by using both DNA barcoding and the morphological classification of Pyraustinae and Spilomelinae, this paper determines the altitudinal gradient pattern for these two subfamilies on the north slope of Mount Taibai, and provides a test of the universality of Rapoport's rule in Lepidoptera by using four methods, including Stevens' method, Pagel's method, Rohde's method, and the cross-species method. Our results show that the alpha diversity of Pyraustinae and Spilomelinae both decrease with rising altitude. By contrast, the species' ranges increase with rising altitude. Three of the four methods used to test Rapoport's rule yielded positive results, while Rohde's results show a unimodal distribution model and do not support Rapoport's rule. Our findings fill the research gap on the elevational diversity of Lepidoptera in temperate Asia. [ABSTRACT FROM AUTHOR]

Historical land-use practices have caused forest loss in Cambodia's Tonle Sap Lake area (TSLA), the largest freshwater lake in Southeast Asia. However, it remains unclear if this deforestation trend had continued since 2001 when the land was designated as protected areas. Using satellite imagery, we investigated forest conversion flows and fragmentation patterns in the TSLA for 1992–2001, 2001–2010, and 2010–2019, respectively. Results show substantial forest losses and fragmentations occurring at the lower floodplain where the protected areas are located until 2010, with some forest regain during 2010–2019. The land conversions indicated that forest clearing and agricultural farming were the primary causes for observed extensive forest loss during 1992–2010. Hence, despite the creating of protected areas in 2001, our findings reveal the persistence of alarming forest loss in the TSLA until 2010. On the other hand, while net forest loss has stopped after 2010, forest regain during 2010–2019 is way too small to restore the region's total forest area to even the level when the protected areas were established. Thus, more effective planning and implementations of forest management and restoration policies are needed for the TSLA. [ABSTRACT FROM AUTHOR]

The cover image is based on the Original Article Cold deep subduction of Indian continental crust and release of ultrahigh‐pressure fluid during initial exhumation: Insights from coesite‐bearing eclogite‐vein systems in Kaghan Valley, Pakistan by Shun Guo et al., https://doi.org/10.1111/jmg.12760.By Shun Guo; Anping Chen; Xirun Cai; Yi Chen; Pan Tang and Qiuli LiReported by Author; Author; Author; Author; Author; Author [Extracted from the article]

Satellite‐derived sun‐induced chlorophyll fluorescence (SIF) has been increasingly used for estimating gross primary production (GPP). However, the relationship between SIF and GPP has not been well defined, impeding the translation of satellite observed SIF to GPP. Previous studies have generally assumed a linear relationship between SIF and GPP at daily and longer time scales, but support for this assumption is lacking. Here, we used the GPP/SIF ratio to investigate seasonal variations in the relationship between SIF and GPP over the Northern Hemisphere (NH). Based on multiple SIF products and MODIS and FLUXCOM GPP data, we found strong seasonal hump‐shaped patterns for the GPP/SIF ratio over northern latitudes, with higher values in the summer than in the spring or autumn. This hump‐shaped GPP/SIF seasonal variation was confirmed by examining different SIF products and was evident for most vegetation types except evergreen broadleaf forests. The seasonal amplitude of the GPP/SIF ratio decreased from the boreal/arctic region to drylands and the tropics. For most of the NH, the lowest GPP/SIF values occurred in October or September, while the maximum GPP/SIF values were evident in June and July. The most pronounced seasonal amplitude of GPP/SIF occurred in intermediate temperature and precipitation ranges. GPP/SIF was positively related to temperature in the early and late parts of the growing season, but not during the peak growing months. These shifting relationships between temperature and GPP/SIF across different months appeared to play a key role in the seasonal dynamics of GPP/SIF. Several mechanisms may explain the patterns we observed, and future research encompassing a broad range of climate and vegetation settings is needed to improve our understanding of the spatial and temporal relationships between SIF and GPP. Nonetheless, the strong seasonal variation in GPP/SIF we identified highlights the importance of incorporating this behavior into SIF‐based GPP estimations. [ABSTRACT FROM AUTHOR]

• We compared vegetation phenology from a SIF product (CSIF) and from MODIS NDVI. • We found similar spatial patterns in CSIF and NDVI derived phenology. • NDVI data indicated an earlier start and later end of the growing season than CSIF. • Models based on leaf greenness may overestimate photosynthesis active period. Vegetation phenology is highly sensitive to climate change, although the data and methods used to estimate key phenological states can influence this sensitivity. Because of its direct relation to leaf photosynthetic carbon uptake, remotely sensed solar-induced chlorophyll fluorescence (SIF) can provide new insight assessing changes in vegetation phenology. Here, we investigated the potential of using a SIF time series product named contiguous SIF (CSIF) to estimate spring, summer, and autumn phenology in the extratropical Northern Hemisphere (>30°N) and compared the results with those based on Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) for the period 2001–2018. Overall, we found similar spatial patterns in phenological states. However, specific dates of key phenological events differed when using CSIF vs. MODIS NDVI data. NDVI data indicated that the growing season started earlier (by 10.1 days on average) and ended later (11.5 days on average) relative to CSIF data. This implies that actual periods for photosynthetic activity are shorter (by 21.6 days on average) than those estimated from vegetation indices more directly related to changes in canopy structure. These large differences between results from NDVI and that from CSIF suggest that vegetation indices such as NDVI seem to overestimate the period for active photosynthesis over the extratropical Northern Hemisphere. Furthermore, while phenology of the early growing season is dominated by temperature for both NDVI and CSIF data, phenology of the late growing season is mainly controlled by temperature for NDVI but by precipitation for CSIF. Our findings were further confirmed by other SIF (GOME-2 SIF) and vegetation index (MODIS EVI) datasets. Phenology modes in Earth system modelling are often parameterized using leaf unfolding and senescence from either station or satellite observations. Our results imply that canopy structure-based parameterization schemes may have overestimated photosynthesis active period, and thus productivity responses. We conclude that SIF data offers a novel and unique approach for assessing phenological change - one that is more directly tied to the carbon cycle and how it is being influenced by climate change. [ABSTRACT FROM AUTHOR]

The Palaeozoic mafic-ultramafic complexes hosting Ni-Cu-Co mineralization occurred discontinuously and coexisted with early Palaeozoic eclogites in the East Kunlun orogenic belt (EKOB), western China. The giant Xiarihamu Cu-Ni-Co sulphide deposit in the EKOB is the largest Cu-Ni-Co sulphide deposit in an orogenic setting in the world. Early Palaeozoic eclogites are distributed as a belt for ca. 530 km in length in the Central Kunlun Zone of the EKOB. The geochronological data, geology and geochemistry of mafic-ultramafic complexes and eclogites in the EKOB are summarized for the tectonic settings of magmatic Cu-Ni-Co mineralization under the Proto- and Paleo-Tethys evolution. The mafic-ultramafic complexes show diverse lithofacies with different formation ages, indicating the multiple stages of long-lived Palaeozoic mantle-derived magmatism in the EKOB. The tectonic location, Neoproterozoic Ocean island basalt (OIB)-like mafic volcanic rocks and eclogite protolith of the EOKB imply the presence of the Neoproterozoic mantle plume magmatism as well as its contribution for enrichments of Ni-Cu-Co beneath EKOB. The ultramafic complexes show a close spatio-temporal relationship with eclogites. The basaltic protoliths of EKOB eclogite were derived from same mantle source as the mafic-ultramafic complexes. A positive correlation of geochronological data between ultramafic complexes with the eclogites in the EKOB is determined and indicated that the mafic magmatism with Cu-Ni-Co mineralization and eclogites were related to the tectonic-magmatic events in process of Proto-Tethys. The ultramafic complexes were formed under the subduction compression and post-collisional extensional settings of the Proto-Tethys and Paleao-Tethys Ocean corresponding to the peak (430–450 Ma) and retrograde (~405–410 Ma) metamorphic periods of eclogites. The Cu-Ni-Co metals were enriched extremely in the stage magma chamber by multi-stage magmatism in EKOB. Therefore, the mafic-ultramafic complexes with a large age span co-occurred with eclogites (especially retrograde eclogites) could be a favourable area for Ni-Co mineralization. [ABSTRACT FROM AUTHOR]

The sensitivity of vegetation productivity to precipitation (Sppt) is a key metric for understanding the variations in vegetation productivity under changing precipitation and predicting future changes in ecosystem functions. However, a comprehensive assessment of Sppt over all the global land is lacking. Here, we investigated spatial patterns and temporal changes of Sppt across the global land from 2001 to 2018 with multiple streams of satellite observations. We found consistent spatial patterns of Sppt with different satellite products: Sppt was highest in dry regions while low in humid regions. Grassland and shrubland showed the highest Sppt, and evergreen needle‐leaf forest and wetland showed the lowest. Temporally, Sppt showed a generally declining trend over the past two decades (p <.05), yet with clear spatial heterogeneities. The decline in Sppt was especially noticeable in North America and Europe, likely due to the increase in precipitation. In central Russia and Australia, however, Sppt showed an increasing trend. Biome‐wise, most ecosystem types exhibited significant decrease in Sppt, while grassland, evergreen broadleaf forest, and mixed forest showed slight increases or non‐significant changes in Sppt. Our finding of the overall decline in Sppt implies a potential stabilization mechanism for ecosystem productivity under climate change. However, the revealed Sppt increase for some regions and ecosystem types, in particular global grasslands, suggests that grasslands might be increasingly vulnerable to climatic variability with continuing global climate change. [ABSTRACT FROM AUTHOR]

Adipogenesis is one of the triggers of obesity, which is a risk factor for various metabolic diseases. Long noncoding RNA steroid receptor RNA activator (lncRNA-SRA) is closely related to adipogenesis and p38/JNK mitogen-activated protein kinase mediates lipid production by regulating peroxisome proliferator-activated receptor gamma (PPARγ). Aerobic exercise can be efficient in improving adiposity and losing weight. Hence, we hypothesize that aerobic exercise ameliorates obesity by affecting the SRA/p38/JNK/PPARγ pathway and downstream target genes. The broad approaches used to test hypotheses are as follows. Spectrophotometer detected C57BL/6J mice blood lipid level; hematoxylin and eosin-stained fat tissue to check the grade of epididymis fat; quantitative polymerase chain reaction and Western blot detected messenger RNA expression and protein levels. Injected lncRNA-SRA virus vector to overexpress SRA. After 8 weeks of aerobic exercise intervention, obese mice showed significant improvements in body weight, white fat weight, lipid levels, and the Lee index. Aerobic exercise significantly inhibited the expression of SRA, activated the p38/JNK signaling pathway, further inhibited the expression of PPARγ and downstream target genes, and improved obesity. Aerobic exercise intervention improved lipid metabolism in obese mice, and the mechanism may be related to the regulation of the LncSRA/p38/JNK/PPARγ signaling pathway. Aerobic exercise is a globally recognized method for weight loss, and aerobic exercise successfully attenuates obesity by suppressing long noncoding steroid receptor RNA activator (lncSRA) expression caused by a high-fat diet. When lncSRA is suppressed, it activates the p38/JNK signaling pathway and further suppresses peroxisome proliferator-activated receptor gamma (PPARγ) and its downstream target genes, such as adipocyte fatty acid-binding protein-2, fatty acid synthase, phosphoenolpyruvate carboxykinase, and glucokinase. Hence, aerobic exercise inhibits lncSRA expression and further activates p38/JNK signaling pathway to suppress PPARγ and its targets expression to improve adipogenesis. [Display omitted] [ABSTRACT FROM AUTHOR]

Wildfires are becoming an increasing challenge to the sustainability of boreal peatland (BP) ecosystems and can alter the stability of boreal carbon storage. However, predicting the occurrence of rare and extreme BP fires proves to be challenging, and gaining a quantitative understanding of the factors, both natural and anthropogenic, inducing BP fires remains elusive. Here, we quantified the predictability of BP fires and their primary controlling factors from 1997 to 2015 using a two-step correcting machine learning (ML) framework that combines multiple ML classifiers, regression models, and an error-correcting technique. We found that (1) the adopted oversampling algorithm effectively addressed the unbalanced data and improved the recall rate by 26.88 %–48.62 % when using multiple datasets, and the error-correcting technique tackled the overestimation of fire sizes during fire seasons; (2) nonparametric models outperformed parametric models in predicting fire occurrences, and the random forest machine learning model performed the best, with the area under the receiver operating characteristic curve ranging from 0.83 to 0.93 across multiple fire datasets; and (3) four sets of factor-control simulations consistently indicated the dominant role of temperature, air dryness, and climate extreme (i.e., frost) for boreal peatland fires, overriding the effects of precipitation, wind speed, and human activities. Our findings demonstrate the efficiency and accuracy of ML techniques in predicting rare and extreme fire events and disentangle the primary factors determining BP fires, which are critical for predicting future fire risks under climate change. [ABSTRACT FROM AUTHOR]

The Mekong River (MR) crosses the borders and connects six countries, including China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. It provides critical water resources and supports natural and agricultural ecosystems, socioeconomic development, and the livelihoods of the people living in this region. Understanding changes in the runoff of this important international river under projected climate change is critical for water resource management and climate change adaptation planning. However, research on long-term runoff dynamics for the MR and the underlying drivers of runoff variability remains scarce. Here, we analyse historical runoff variations from 1971 to 2020 based on runoff gauge data collected from eight hydrological stations along the MR. With these runoff data, we then evaluate the runoff simulation performance of five global hydrological models (GHMs) forced by four global climate models (GCMs) under the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP). Furthermore, based on the best simulation combination, we quantify the impact of future climate change on river runoff changes in the MR. The result shows that the annual runoff in the MR has not changed significantly in the past 5 decades, while the establishment of dams and reservoirs in the basin visibly affected the annual runoff distribution. The ensemble-averaged result of the Water Global Assessment and Prognosis version 2 (WaterGAP2; i.e. GHM) forced by four GCMs has the best runoff simulation performance. Under Representative Concentration Pathways (RCPs; i.e. RCP2.6, RCP6.0 and RCP8.5), the runoff of the MR is projected to increase significantly (p<0.05); e.g. 3.81 ± 3.47 m3s-1a-1 (9 ± 8 % increase in 100 years) at the upper reach under RCP2.6 and 16.36 ± 12.44 m3s-1a-1 (13 ± 10 % increase in 100 years) at the lower reach under RCP6.0. In particular, under the RCP6.0 scenario, the increase in annual runoff is most pronounced in the middle and lower reaches, due to increased precipitation and snowmelt. Under the RCP8.5 scenario, the runoff distribution in different seasons varies obviously, increasing the risk of flooding in the wet season and drought in the dry season. [ABSTRACT FROM AUTHOR]

Background and Purpose: Senescence in hepatic stellate cells (HSCs) limits liver fibrosis. Glutaminolysis promotes HSC activation. Here, we investigated how emodin affected HSC senescence involving glutaminolysis. Experimental Approach: Senescence, glutaminolysis metabolites, Nur77 nuclear translocation, glutaminase 1 (GLS1) promoter methylation and related signalling pathways were examined in human HSC‐LX2 cells using multiple cellular and molecular approaches. Fibrotic mice with shRNA‐mediated knockdown of Nur77 were treated with emodin‐vitamin A liposome for investigating the mechanisms in vivo. Human fibrotic liver samples were examined to verify the clinical relevance. Key Results: Emodin upregulated several key markers of senescence and inhibited glutaminolysis cascade in HSCs. Emodin promoted Nur77 nuclear translocation, and knockdown of Nur77 abolished emodin blockade of glutaminolysis and induction of HSC senescence. Mechanistically, emodin facilitated Nur77/DNMT3b interaction and increased GLS1 promoter methylation, leading to inhibited GLS1 expression and blockade of glutaminolysis. Moreover, the glutaminolysis intermediate α‐ketoglutarate promoted extracellular signal‐regulated kinase (ERK) phosphorylation, which in turn phosphorylated Nur77 and reduced its interaction with DNMT3b. This led to decreased GLS1 promoter methylation and increased GLS1 expression, forming an ERK/Nur77/glutaminolysis positive feedback loop. However, emodin repressed ERK phosphorylation and interrupted the feedback cascade, stimulating senescence in HSCs. Studies in mice showed that emodin‐vitamin A liposome inhibited glutaminolysis and induced senescence in HSCs, and consequently alleviated liver fibrosis; but knockdown of Nur77 abrogated these beneficial effects. Similar alterations were validated in human fibrotic liver tissues. Conclusions and Implications: Emodin stimulated HSC senescence through interruption of glutaminolysis. HSC‐targeted delivery of emodin represented a therapeutic option for liver fibrosis. [ABSTRACT FROM AUTHOR]

This study develops a convolutional recurrent deep learning model to accurately predict fine‐resolution spatiotemporal changes in grass coverage in arid regions. Applying the model to the Gobi Desert reveals that ecological flow regulation contributes to 61.8% of the total increase in grass cover (130.6 km2) in the study area (40,423 km2) over 2005–2015, nearly triple the contribution of local climate change (+23.0%). The transboundary hydrological impact (+32.4%) and interactions between drivers (−17.2%) are also significant. In an intermediate future climate change scenario, we found no statistically significant trend for the total grass‐covered area due to the counteracting effects among different drivers. The study findings suggest that timely, adaptive and spatially heterogeneous ecological flow management is crucial for addressing grassland degradation in arid regions. This study provides a promising approach to land surface modeling under climate change and human disturbance and expands the existing understanding of the global greening process. Plain Language Summary: The Earth's recent greening (i.e., vegetation increase) has boosted the terrestrial carbon sink, intensified the hydrologic cycle, and contributed to mitigating global warming. CO2 fertilization has been identified as the primary cause at the global scale, while climate change, land use changes, and nitrogen deposition also contribute. However, there are still many gaps in our understanding of how grasslands in arid areas are being affected. Studies in Central Asia identified precipitation as the dominant factor affecting grassland change and grazing as the main influence from humans. Based on satellite data, we employ a novel deep learning (DL) approach to emulate spatiotemporal changes in grass coverage at a 1‐km resolution over an area of 40,423 km2 in the Gobi Desert in northwestern China. Our study identified previously overlooked mechanisms contributing to the increase in grass coverage, including ecological flow management and transboundary hydrological impact. Ecological flow management was found to be responsible for almost three times the increase in grass coverage over 2005–2015 than that of local climate changes. Our findings suggest that timely, adaptive, and spatially targeted ecological flow management is urgently needed to prevent further grassland degradation in arid regions, and DL‐based artificial intelligence can offer valuable management suggestions. Key Points: Deep learning (DL) precisely emulates spatiotemporal changes in grass coverage at a 1‐km resolution over an area of 40,423 km2DL interprets ecological flow regulation (EFR) as the leading cause of grassland greening in the Gobi DesertTimely, adaptive and spatially heterogeneous ecological flow management is desired to prevent grassland degradation in arid regions [ABSTRACT FROM AUTHOR]

Global greening, characterized by an increase in leaf area index (LAI), implies an increase in foliar carbon (C). Whether this increase in foliar C under climate change is due to higher photosynthesis or to higher allocation of C to leaves remains unknown. Here, we explored the trends in foliar C accumulation and allocation during leaf green‐up from 2000 to 2017 using satellite‐derived LAI and solar‐induced chlorophyll fluorescence (SIF) across the Northern Hemisphere. The accumulation of foliar C accelerated in the early green‐up period due to both increased photosynthesis and higher foliar C allocation driven by climate change. In the late stage of green‐up, however, we detected decreasing trends in foliar C accumulation and foliar C allocation. Such stage‐dependent trends in the accumulation and allocation of foliar C are not represented in current terrestrial biosphere models. Our results highlight that a better representation of C allocation should be incorporated into models. [ABSTRACT FROM AUTHOR]

Negative extreme anomalies in vegetation growth (NEGs) usually indicate severely impaired ecosystem services. These NEGs can result from diverse natural and anthropogenic causes, especially climate extremes (CEs). However, the relationship between NEGs and many types of CEs remains largely unknown at regional and global scales. Here, with satellite‐derived vegetation index data and supporting tree‐ring chronologies, we identify periods of NEGs from 1981 to 2015 across the global land surface. We find 70% of these NEGs are attributable to five types of CEs and their combinations, with compound CEs generally more detrimental than individual ones. More importantly, we find that dominant CEs for NEGs vary by biome and region. Specifically, cold and/or wet extremes dominate NEGs in temperate mountains and high latitudes, whereas soil drought and related compound extremes are primarily responsible for NEGs in wet tropical, arid and semi‐arid regions. Key characteristics (e.g., the frequency, intensity and duration of CEs, and the vulnerability of vegetation) that determine the dominance of CEs are also region‐ and biome‐dependent. For example, in the wet tropics, dominant individual CEs have both higher intensity and longer duration than non‐dominant ones. However, in the dry tropics and some temperate regions, a longer CE duration is more important than higher intensity. Our work provides the first global accounting of the attribution of NEGs to diverse climatic extremes. Our analysis has important implications for developing climate‐specific disaster prevention and mitigation plans among different regions of the globe in a changing climate. [ABSTRACT FROM AUTHOR]

Large‐scale reforestation can potentially bring both benefits and risks to the water cycle, which needs to be better quantified under future climates to inform reforestation decisions. We identified 477 water‐insecure basins worldwide accounting for 44.6% (380.2 Mha) of the global reforestation potential. As many of these basins are in the Asia‐Pacific, we used regional coupled land‐climate modeling for the period 2041–2070 to reveal that reforestation increases evapotranspiration and precipitation for most water‐insecure regions over the Asia‐Pacific. This resulted in a statistically significant increase in water yield (p <.05) for the Loess Plateau–North China Plain, Yangtze Plain, Southeast China, and Irrawaddy regions. Precipitation feedback was influenced by the degree of initial moisture limitation affecting soil moisture response and thus evapotranspiration, as well as precipitation advection from other reforested regions and moisture transport away from the local region. Reforestation also reduces the probability of extremely dry months in most of the water‐insecure regions. However, some regions experience nonsignificant declines in net water yield due to heightened evapotranspiration outstripping increases in precipitation, or declines in soil moisture and advected precipitation. [ABSTRACT FROM AUTHOR]

The role of aerobic exercise in preventing and improving non-alcoholic fatty liver has been widely established. SRA is a long non-coding RNA, which has received increasing attention due to its important role in lipid metabolism. However, it is unclear whether aerobic exercise can prevent and treat hepatic lipid accumulation via SRA. The mice were randomly divided into four groups as follows, normal control group, normal aerobic exercise group, high-fat diet group (HFD), and high-fat diet plus aerobic exercise (8 weeks, 6 days/week, 18 m/min for 50 min, 6% slope) group (HAE). After 8 weeks, the mice in the HAE group showed significant improvement in hepatic steatosis. Body weight as well as blood TC, LDL-C, and liver TG levels were significantly lower in the HAE group than in the HFD group. Compared with the HFD group, the expression of SRA was markedly suppressed and the expression of ATGL was significantly increased in the HAE group. Additionally, the JNK/P38 signaling was inhibited, the pro-inflammatory factors were down-regulated, and the anti-inflammatory factor was increased. In addition to this, the same results were shown in experiments with overexpression of SRA. The results of this study provided new support for aerobic exercise to improve hepatic lipid metabolism via lncRNA. [ABSTRACT FROM AUTHOR]

This study analyzed the effects of aerobic exercise on endogenous serum metabolites in response to chronic unpredictable mild stress (CUMS) using a rat model, aiming to identify the metabolic regulatory pathways involved in the antidepressant effect resulted from a 28-day treadmill aerobic exercise intervention. The animals were randomly divided into four groups (n = 8): normal control, normal with aerobic exercise, CUMS control, and CUMS with aerobic exercise. Body weight, sucrose preference and open field tests were performed weekly during the intervention period for changes in depressant symptoms. Serum metabolic profiles obtained by using the LC–MS/MS metabolomics were analyzed to explore the regulatory mechanism for the effect of the aerobic exercise on depression. Behavior tests showed that the aerobic exercise resulted in a significant improvement in depression-like behavior in the CUMS rats. A total of 21 differential metabolites were identified as being associated with depression in serum metabolic profile, of which the aerobic exercise significantly modulated 15, mainly related to amino acid metabolism and energy metabolism. Collectively, this is the first study that LC–MS/MS techniques were used to reveal the modulatory effects of aerobic exercise on the serum metabolic profile of depressed rats and the findings further enriched our understanding of potential mechanisms of aerobic exercise interventions on depression. [ABSTRACT FROM AUTHOR]

Activation of hepatic stellate cells (HSCs) is a central event in the development of liver fibrosis, and the elimination of activated HSCs is considered to be an effective anti-fibrotic strategy. Here, we report that dihydroartemisinin (DHA) prevented the activation of HSCs via ferroptosis pathway. Importantly, DHA treatment increased the level of autophagy in HSCs. The inhibition of autophagy by 3-MA dramatically abolished the DHA-induced ferroptosis in HSCs. Mechanistically, the up-regulated m6A modification is essential for the activation of autophagy by DHA through the reduction of fat mass and obesity-associated gene (FTO). Down-regulation of m6A modification by FTO overexpression could impair autophagy and the classical ferroptotic events. Interestingly, the m6A modification of BECN1 mRNA was evidently up-regulated compared with other autophagy-related genes. More importantly, YTHDF1 was identified as a key m6A reader protein for BECN1 mRNA stability, and knockdown of YTHDF1 could prevent DHA-induced HSC ferroptosis. Noteworthy, YTH domain was essential for YTHDF1 to prolong the half-life of BECN1 mRNA in DHA-induced HSC ferroptosis. In mice, DHA treatment alleviated liver fibrosis by triggering HSC ferroptosis. HSC-specific inhibition of m6A modification and autophagy could impair DHA-induced HSC ferroptosis in murine liver fibrosis. Overall, these results provided novel implications to reveal the molecular mechanism of DHA-induced ferroptosis, by which pointed to m6A modification-dependent ferroptosis as a potential target for the treatment of liver fibrosis. [Display omitted] • DHA inhibits HSC activation via ferroptosis pathway. • The activation of autophagy is required for DHA-induced ferroptosis in HSCs. • The m6A modification is associated with DHA-induced autophagy and ferroptosis in HSCs. [ABSTRACT FROM AUTHOR]

Tumor-associated macrophages (TAMs) are critical components of the tumor microenvironment that are tightly associated with malignancies in human cancers, including lung cancer. LGK-974, a small molecular inhibitor of Wnt secretion, was reported to block Wnt/β-catenin signaling and exert anti-inflammatory effects by suppressing pro-inflammatory gene expression in cancer cells. Although it was reported that Wnt/β-catenin was critical in regulating TAMs, it is still largely unknown whether LGK-974 regulates tumor malignancies by regulating TAMs. The present study firstly verified that the polarization of TAMs was regulated by LGK-974. LGK-974 increased M1 macrophage functional markers and decreased M2 macrophage functional markers. The addition of Wnt3a and Wnt5a, two canonical Wnt signaling inducers, reversed the decrease in M1 macrophage functional markers, including mannose receptor, IL-10 and Arg1, by activating Wnt/β-catenin signaling. Conditioned medium from LGK-974-modified TAMs inhibited the malignant behaviors in A549 and H1299 cells, including proliferation, colony formation and invasion, by blocking Wnt/β-catenin signaling. LGK-974-modified TAMs blocked the cell cycle at the G1/G0 phase, which was reversed by the addition of Wnt3a/5a, indicating that LGK-974 regulates the microenvironment by blocking Wnt/β-catenin signaling. Taken together, the results indicate that LGK-974 indirectly inhibited the malignant behaviors of A549 and H1299 cells by regulating the inflammatory microenvironment by inhibiting Wnt/β-catenin signaling in TAMs. [ABSTRACT FROM AUTHOR]

Targeting the elimination of activated hepatic stellate cells (HSCs) and blocking excessive deposition of extracellular matrix are recognized as an effective strategy for the treatment of hepatic fibrosis. As a newly discovered programmed cell death mode, the regulatory mechanism of ferroptosis in the clearance of activated HSCs has not been fully elucidated. In the present study, we reported that the induction of ferroptosis in activated HSCs was required for dihydroartemisinin (DHA) to alleviate hepatic fibrosis. Treatment with DHA could improve the damage of hepatic fibrosis in vivo and inhibit the activation of HSCs in vitro. Interestingly, DHA treatment could trigger ferroptosis to eliminate activated HSCs characterized by iron overload, lipid ROS accumulation, glutathione depletion, and lipid peroxidation. Specific ferroptosis inhibitors ferrostatin‐1 and liproxstatin‐1 could impair DHA‐induced ferroptosis and also damage DHA‐mediated the inhibition of activated HSCs. Importantly, autophagy activation may be closely related to DHA‐induced ferroptosis. ATG5 siRNA could prevent DHA‐mediated autophagy activation and ferroptosis induction, whereas ATG5 plasmid could promote the effect of DHA on autophagy and ferroptosis. Of note, the upregulation of nuclear receptor coactivator 4 (NCOA4) may play a critical role in the molecular mechanism. NCOA4 siRNA could impair DHA‐induced ferroptosis, whereas NCOA4 plasmid could enhance the promoting effect of DHA on ferroptosis. Overall, our study revealed the potential mechanism of DHA against hepatic fibrosis and showed that ferroptosis could be a new way to eliminate activated HSCs. [ABSTRACT FROM AUTHOR]

Objective: The benefit of Se supplementation in rheumatoid arthritis (RA) has been tested in clinical trials, but results remain inconclusive. The objective of this study was to specifically investigate the potential benefit of supranutritional Se by examining human samples from an area with supranutritional Se intake and testing a mouse model of RA. Methods: Peripheral blood mononuclear cells (PBMCs) from RA patients (N = 57) and healthy controls (HC, N = 71) from an area of supranutritional Se intake (Enshi, Hubei, China) were analysed by flow cytometry. Serum cytokine and Se levels were measured by cytometric beads array (CBA) and inductively coupled plasma mass spectrometry (ICP‐MS), respectively. With sufficient or supranutritional selenium intake, mice were induced with collagen‐induced arthritis (CIA) and examined for disease activity and immunopathology. The influence of Se supplementation in the generation of RANKL‐expressing osteoclastogenic CD4+ T cells was investigated by in vitro assays. Results: In Enshi city, HC showed the above‐normal concentrations of serum Se concentrations while RA patients were enriched in the normal range (70–150 ng mL−1) or below. RA patients with higher Se levels demonstrated milder disease and lower levels of C‐reactive protein, IL‐6, RANKL and Th17 cells. In the mouse CIA model, supranutritional Se supplementation delayed disease onset, ameliorated joint pathology and reduced CD4+CD44+RANKL+ T cells. Se supplementation could suppress RANKL expression in cultured mouse Th17 cells. Conclusion: Supranutritional Se suppresses RANKL‐expressing osteoclastogenic CD4+ T cells and could be beneficial to RA, which warrants formal testing in randomised clinical trials. [ABSTRACT FROM AUTHOR]

Aims: This study was designated to illustrate the underlying mechanisms of emodin anti‐liver fibrosis via network pharmacology and experiment. Methods: The TSMCP and Genecards database were applied to screen the relevant targets of emodin or liver fibrosis. The essential target was selected by using Cytoscape to analyze the topological network of potential targets. Furthermore, we constructed a preliminary molecule docking study to explore the binding site by Surflex‐Dock suite SYBYL X 2.0. The DAVID database was selected for gene functional annotations and KEGG enrichment analysis. Moreover, we demonstrated the ameliorating effect of emodin on carbon tetrachloride (CCl4)‐induced liver injury in mice. We also verified the network predictions in vitro via various techniques. Results: The collected results showed that 35 targets were related to emodin, and 6,198 targets were associated with liver fibrosis. The Venn analysis revealed that 17 intersection targets were correlated with emodin anti‐liver fibrosis. The topological network analysis suggested that the p53 was the remarkable crucial target. Besides, the molecule docking results showed that emodin could directly interact with p53 by binding the active site residues ASN345, GLN331, and TYR347. Finally, KEGG pathway enrichment results indicated that essential genes were mainly enriched in mitogen‐activated protein kinase (MAPK) signaling pathways. Moreover, our study confirmed that emodin alleviated CCl4‐induced liver injury in mice, inducing hepatic stellate cells (HSCs) apoptosis via regulating the p53/ERK/p38 axis. Conclusions: This study partially verified the network pharmacological prediction of emodin inducing HSCs cell apoptosis through the p53/ERK/p38 axis. [ABSTRACT FROM AUTHOR]

Iron accumulation is frequently associated with chronic liver diseases. However, our knowledge on how iron contributes to the liver injury is limited. Aberrant Wnt/b-catenin signaling is a hallmark of several hepatic pathologies. We recently reported that peroxisome proliferator-activated receptor a (PPARa) agonist, fenofibrate, prevents iron-induced oxidative stress and b-catenin signaling by chelating the iron. Sirtuin3 (Sirt3), a type of NADþ-dependent deacetylase, that plays a critical role in metabolic regulation was found to prevent ischemia reperfusion injury (IRI) by normalizing the Wnt/β-catenin pathway. In the present study, we explored if fenofibrate prevents iron-induced liver injury by regulating the Sirt3 and β-catenin signaling. In vitro and in vivo iron treatment resulted in the downregulation of PPARa, Sirt3, active β-catenin, and its downstream target gene c-Myc in the mouse liver. Pharmacological activation of Sirt3, both in vitro and in vivo, by Honokiol (HK), a known activator of Sirt3, abrogated the inhibitory effect of iron overload on active β-catenin expression and prevented the iron-induced upregulation of a smooth muscle actin (aSMA) and TGFb expression. Intrinsically, PPARa knockout mice showed significant downregulation of hepatic Sirt3 levels. In addition, treatment of iron overload mice with PPARa agonist fenofibrate reduced hepatic iron accumulation and prevented iron-induced downregulation of liver Sirt3 and active β-catenin, mitigating the progression of fibrosis. Thus, our results establish a novel link between hepatic iron and PPARa, Sirt3, and β-catenin signaling. Further exploration on the mechanisms by which fenofibrate ameliorates iron-induced liver injury likely has significant therapeutic impact on iron-associated chronic liver diseases. [ABSTRACT FROM AUTHOR]

The 2015−2016 El Niño was one of the strongest on record, but its influence on the carbon balance is less clear. Using Northern Hemisphere atmospheric CO2 observations, we found both detrended atmospheric CO2 growth rate (CGR) and CO2 seasonal‐cycle amplitude (SCA) of 2015−2016 were much higher than that of other El Niño events. The simultaneous high CGR and SCA were unusual, because our analysis of long‐term CO2 observations at Mauna Loa revealed a significantly negative correlation between CGR and SCA. Atmospheric inversions and terrestrial ecosystem models indicate strong northern land carbon uptake during spring but substantially reduced carbon uptake (or high emissions) during early autumn, which amplified SCA but also resulted in a small anomaly in annual carbon uptake of northern ecosystems in 2015−2016. This negative ecosystem carbon uptake anomaly in early autumn was primarily due to soil water deficits and more litter decomposition caused by enhanced spring productivity. Our study demonstrates a decoupling between seasonality and annual carbon cycle balance in northern ecosystems over 2015−2016, which is unprecedented in the past five decades of El Niño events. [ABSTRACT FROM AUTHOR]

Warming drives poleward expansion of forests over high latitudes. However, it remains unresolved whether the poleward forest lines can track the warming rate at continental scales. To answer this question, we compared latitudinal forest line shifts detected by remote sensing under the early 21st century's warming (i.e., from 2000 to 2019) with shifts of temperature isolines derived from a time-invariant temperature-forest line relationship. The results show that the northward forest line shift in North America (NA) can generally keep pace with changes in temperature isolines; while in Eurasia (EA) it greatly trails that of temperature changes. Therefore, the northward shift of the forest line tracking temperature warming over NA is much faster than that over EA. The slower warming rate over NA allows slow temperature acclimation. In contrast, the warming rate is much faster in EA, which makes other environmental factors (e.g., winter temperature, water stress, and active layer thickness, biotic factors, and land use and land cover change) increasingly important in limiting the northward shift of forest lines. • Warming has led to northward shifts of forest lines in northern high latitudes. • The northward shift of forest lines is much faster in North America than in Eurasia. • Differences in warming acclimation can help explain the divergent northward shifts. [ABSTRACT FROM AUTHOR]

• AR is more sensitive to nitrogen addition and grazing than HR. • N addition and grazing had additive effects on AR. • Aboveground biomass is the predominant controlling factor and key predictor of AR. • N addition, grazing and their interaction had no significant effects on HR. • Grazing dampened the positive response of Q 10 of HR to N addition. A quantitative understanding of temporal patterns of soil respiration (SR) and its components, as well as of their controlling factors, are key to the estimation of grassland C sequestration under different scenarios of land-use change and global change. However, the sensitivity of seasonal patterns and magnitude of SR and its components to N addition (N) and grazing (G) and their interactions remains poorly understood. We carried out an experiment with N, G and N addition plus grazing (NG) treatments in temperate meadow steppe located in the easternmost of the Eurasian steppe. We measured SR and its components, i.e., autotrophic respiration (AR) and heterotrophic respiration (HR), along with a suite of other biotic and abiotic factors over 3 years. N addition increased AR when compared to the control treatment (CK), whereas moderate grazing decreased AR, and N addition and grazing had additive effects on AR. We found that aboveground biomass was the predominant controlling factor of AR. However, the N, G and NG treatments had no significant effects on HR. Although N addition and grazing caused changes in a series of biotic and abiotic factors (e.g. total PLFAs, soil fungal/bacterial ratio and bulk density) that controlled soil microbial metabolic processes, collectively these effects on HR appeared to offset each other. Moreover, compared to the CK and N treatments, G and NG treatments reduced the apparent temperature sensitivity (Q 10) of AR and HR. Grazing dampened the positive response of Q 10 of HR to N addition. Our study suggests that AR and HR are regulated by different underlying mechanisms and respond differently to N and G, and therefore should be modeled separately to improve models and predictions of ecosystem C cycling. Our study also indicates that moderate grazing could produce beneficial effects on meadow steppe carbon sequestration under future scenarios of nitrogen deposition and climate warming. [ABSTRACT FROM AUTHOR]

[Display omitted] Activation of hepatic stellate cells (HSCs) is a central event in the pathogenesis of liver fibrosis and is often accompanied by the disappearance of lipid droplets (LDs). Although interference with LD metabolism can effectively reverse the activation of HSCs, there is currently no effective therapy for liver fibrosis. Our previous evidence indicates that long non-coding RNA (lncRNA)-H19 plays an essential role in LD metabolism of HSC. In this study, we investigated the potential molecular mechanism of dihydroartemisinin (DHA) inhibits LD metabolism and liver fibrosis by regulating H19-AMPK pathway. We found that DHA restores LDs content in activated HSCs via reducing the transcription of H19 driven by hypoxia inducible factor 1 subunit alpha (HIF1α) and inhibiting the lipid oxidation signal mediated by AMP-activated protein kinase (AMPK) phosphorylation. In vivo experiments, we have proved that DHA reduced the deposition of extracellular matrix (ECM) and reduce the level of liver fibrosis in CCl 4 -induced liver fibrosis of mice. In summary, our results emphasize the importance of H19 in liver fibrosis and the potential of DHA to regulate H19 to treat liver fibrosis, providing a new direction for the prevention and treatment of liver fibrosis. [ABSTRACT FROM AUTHOR]