The dominant influencing factors of desertification and ecological risk changes in Qinghai Area of Qilian Mountains National Park: Climate change or human activity?

Transitional features of desert environments partially determine the risks associated with ecosystems. Influenced by climate change and human activities, the variability and uncertainty of desertification levels and ecological risks in the Qinghai Area of Qilian Mountain National Park (QMNPQA) has become increasingly prominent. As a critical ecological barrier in northwest China, monitoring desertification dynamics and ecological risks is crucial for maintaining ecosystem stability. This study identifies the optimal monitoring model from four constructed desertification monitoring models and analyzes spatiotemporal changes in desertification. The spatial and temporal changes in ecological risks and their primary driving factors were analyzed using methods such as raster overlay calculation, geographic detector, cloud model, and trend analysis. The main conclusions are as follows: The desertification feature spatial model based on GNDVI-Albedo demonstrates better applicability in the study area, with an inversion accuracy of 81.24%. The levels of desertification and ecological risks in QMNPQA exhibit significant spatial heterogeneity, with a gradual decrease observed from northwest to southeast. From 2000 to 2020, there is an overall decreasing trend in desertification levels and ecological risks, with the decreasing trend area accounting for 89.82% and 85.71% respectively, mainly concentrated in the southeastern and northwestern parts of the study area. The proportion of areas with increasing trends is 4.49% and 7.05% respectively, scattered in patches in the central and southern edge areas. Surface temperature (ST), Digital Elevation Map (DEM), and Green normalized difference vegetation index (GNDVI) are the most influential factors determining the spatial distribution of ecological risks in QMNPQA. The effects of management and climatic factors on ecological risks demonstrate a significant antagonistic effect, highlighting the positive contributions of human activities in mitigating the driving effects of climate change on ecological risks. The research results can provide reference for desertification prevention and ecological quality improvement in QMNPQA.

Changes of soil carbon along precipitation gradients in three typical vegetation types in the Alxa desert region, China.

The changes and influencing factors of soil inorganic carbon (SIC) and organic carbon (SOC) on precipitation gradients are crucial for predicting and evaluating carbon storage changes at the regional scale. However, people's understanding of the distribution characteristics of SOC and SIC reserves on regional precipitation gradients is insufficient, and the main environmental variables that affect SOC and SIC changes are also not well understood. Therefore, this study focuses on the Alxa region and selects five regions covered by three typical desert vegetation types, Zygophyllum xanthoxylon (ZX), Nitraria tangutorum (NT), and Reaumuria songarica (RS), along the climate transect where precipitation gradually increases. The study analyzes and discusses the variation characteristics of SOC and SIC under different vegetation and precipitation conditions. The results indicate that both SOC and SIC increase with the increase of precipitation, and the increase in SOC is greater with the increase of precipitation. The average SOC content in the 0-300cm profile is NT (4.13 g kg-1) > RS (3.61 g kg-1) > ZX (3.57 g kg-1); The average value of SIC content is: RS (5.78 g kg-1) > NT (5.11 g kg-1) > ZX (5.02 g kg-1). Overall, the multi-annual average precipitation (MAP) in the Alxa region is the most important environmental factor affecting SIC and SOC.

Mechanistic role of RND3-regulated IL33/ST2 signaling on cardiomyocyte senescence.

Hyperinflammatory responses are pivotal in the cardiomyocyte senescence pathophysiology, with IL33 serving as a crucial pro-inflammatory mediator. Our previous findings highlighted RND3's suppressive effect on IL33 expression. This study aims to explore the role of RND3 in IL33/ST2 signaling activation and in cardiomyocyte senescence. Intramyocardial injection of exogenous IL33 reduces the ejection fraction and fractional shortening of rats, inducing the appearance of senescence-associated secretory phenotype (SASP) in myocardial tissues. Recombinant IL33 treatment of AC16 cardiomyocytes significantly upregulated expression of SASP factors like IL1α, IL6, and MCP1, and increased the p-p65/p65 ratio and proportions of SA-ß-gal and γH2AX-positive cells. NF-κB inhibitor pyrrolidinedithiocarbamate ammonium (PDTC) and ST2 antibody astegolimab treatments mitigated above effects. RND3 gene knockout H9C2 cardiomyocytes using CRISPR/Cas9 technology upregulated IL33, ST2L, IL1α, IL6, and MCP1 levels, decreased sST2 levels, and increased SA-ß-gal and γH2AX-positive cells. A highly possibility of binding between RND3 and IL33 proteins was showed by molecular docking and co-immunoprecipitation, and loss of RND3 attenuated ubiquitination mediated degradation of IL33; what's more, a panel of ubiquitination regulatory genes closely related to RND3 were screened using qPCR array. In contrast, RND3 overexpression in rats by injection of AAV9-CMV-RND3 particles inhibited IL33, ST2L, IL1α, IL6, and MCP1 expression in cardiac tissues, decreased serum IL33 levels, and increased sST2 levels. These results suggest that RND3 expression in cardiomyocytes modulates cell senescence by inhibiting the IL33/ST2/NF-κB signaling pathway, underscoring its potential as a therapeutic target in cardiovascular senescence.

The Euphrates Poplar Responses to Abiotic Stress and Its Unique Traits in Dry Regions of China (Xinjiang and Inner Mongolia): What Should We Know?

At the moment, drought, salinity, and low-temperature stress are ubiquitous environmental issues. In arid regions including Xinjiang and Inner Mongolia and other areas worldwide, the area of tree plantations appears to be rising, triggering tree growth. Water is a vital resource in the agricultural systems of countries impacted by aridity and salinity. Worldwide efforts to reduce quantitative yield losses on Populus euphratica by adapting tree plant production to unfavorable environmental conditions have been made in response to the responsiveness of the increasing control of water stress. Although there has been much advancement in identifying the genes that resist abiotic stresses, little is known about how plants such as P. euphratica deal with numerous abiotic stresses. P. euphratica is a varied riparian plant that can tolerate drought, salinity, low temperatures, and climate change, and has a variety of water stress adaptability abilities. To conduct this review, we gathered all available information throughout the Web of Science, the Chinese National Knowledge Infrastructure, and the National Center for Biotechnology Information on the impact of abiotic stress on the molecular mechanism and evolution of gene families at the transcription level. The data demonstrated that P. euphratica might gradually adapt its stomatal aperture, photosynthesis, antioxidant activities, xylem architecture, and hydraulic conductivity to endure extreme drought and salt stress. Our analyses will give readers an understanding of how to manage a gene family in desert trees and the influence of abiotic stresses on the productivity of tree plants. They will also give readers the knowledge necessary to improve biotechnology-based tree plant stress tolerance for sustaining yield and quality trees in China's arid regions.

Water use strategies of Nitraria tangutorum in the lake-basin region of the Badain Jaran Desert.

Information regarding plant water-use strategies is essential for understanding the hydrological processes and plant survival adaptation mechanisms in desert lake basin regions. To examine the water use strategies of plants in desert lake basin areas, water uptake patterns, water use efficiency, and water potential of Nitraria tangutorum were investigated at different distances from the lake duringhe growing seasons in the lake basin regions of the Badain Jaran Desert. The results indicate that N. tangutorum primarily absorbed groundwater in May (63.8%) and August (53.5%), relied on deep soil water in June (75.1%), and uniformly absorbed soil water from different layers in July. These observations could be explained by periodic fluctuations in the groundwater level and the consequent decrease in soil water availability, as well as plant root adjustments. As soil water availability decreases, N. tangutorum adapts to water variation by increasing its water use efficiency (WUE) and reducing its leaf water potential (Ψ). With intensified water stress, N. tangutorum gradually shifted from adventurous anisohydric regulation to conservative isohydric regulation. Thus, N. tangutorum responds to diverse degrees of environmental changes by altering its water-use strategy. A better understanding of the adaptive water use strategies developed by desert plants under varying water availability conditions provides insight into the diversity of species' reactions to long-term drought and quantifies the hydrological cycle of desert ecosystems against the background of worldwide climate warming.

Response of soil water content temporal stability to stand age of Haloxylon ammodendron plantation in Alxa Desert, China.

Afforestation as an effective measure for wind and sand control has achieved remarkable results in northern China, and has also greatly changed the land use and vegetation characteristics of the region. It is important to study the spatial and temporal dynamics of soil water content (SWC) in different afforestation years and its temporal stability to understand the dynamic characteristics of SWC during afforestation. In order to reveal the spatiotemporal dynamic characteristics of SWC in desert area Haloxylon ammodendron (HA)plantations, in this study, five restorative-aged HA plantations in desert areas were selected and their SWC was measured in stratified layers for the 0-400 cm soil profile; we also analyzed the spatiotemporal dynamics and temporal stability of the SWC. The results showed that the SWC of HA plantations decreased with the increase in planting age in the measurement period, and the SWC of deep layers increased by more than that of shallow layers with planting age. Spearman's rank correlation coefficients for SWC of 0-400 cm in both 5- and 11-year-old HA plantations reached above 0.8 and were highly significantly correlated; the temporal stability of SWC tends to increase as the depth of the soil layer deepens. In contrast, the temporal stability of SWC in deeper layers (200-400 cm) of 22-, 34- and 46-year-old stands showed a decreasing trend with depth. Based on the relative difference analysis, representative sampling points can be selected to monitor the regional average SWC, but for older HA plantations, the uncertainty factor of stand age should be considered in the regional moisture simulation. This study verified that it is feasible to simulate large-scale SWC in fewer observations for HA plantations younger than 11 years old, while large errors exist for older stands, especially for deeper soils. This will help soil moisture management in HA plantations in arid desert areas.

Effects of long-term afforestation on soil water and carbon in the Alxa Plateau.

Plantations in dry and semi-arid areas significantly affect the soil's ability to store carbon and maintain a stable water balance. It is yet unclear, though, how planted trees in these regions might impact the soil's carbon and water levels. As a forest ages, it is unknown how soil water and soil carbon interact with one another. In order to conduct this study, four Saxaul plantations in the Alxa Plateau were chosen, with the neighboring mobile sandy (MS) ground serving as a control. The ages of the plantations ranged from 5 to 46 years. The major topics of the study included the relationship between soil water and soil carbon, changes in the 0-300 cm soil layer's soil water content (SWC), soil organic carbon (SOC), and soil inorganic carbon (SIC) following afforestation. The findings demonstrated that, in comparison to MS, afforestation considerably increased SOC and SIC stocks. In comparison to MS, the SIC grew by 4.02 kg m-2, 4.12 kg m-2, 5.12 kg m-2, and 6.52 kg m-2 throughout periods of 5 years, 11 years, 22 years, and 46 years, respectively. SOC increased relative to MS by 2.55 kg m-2, 2.91 kg m-2, 3.53 kg m-2, and 4.05 kg m-2. Afforestation, however, also contributed to a considerable decline in deep SWC and an increase in the soil water deficit (SWD). In comparison to MS, the mean SWC values were lower at 5 years, 11 years, 22 years, and 46 years, respectively, by 0.48%, 1.37%, 1.56%, and 4.00%. The increase in soil carbon pool caused by sand afforestation actually came at the expense of a reduction in soil water due to a large negative association between deep SWC, SOC, and SIC. To limit SWC losses and encourage sustainable forest land development, we advocate suitable harvest management practices on forest land.

Biomimetic dual-responsive bioengineered nanotheranostics for intracellular cascade-synthesizing chemo-drugs and efficient oncotherapy.

Intracellular-synthesized chemo-drugs based on the inherent characteristics of the tumor microenvironment (TME) have been extensively applied in oncotherapy. However, combining other therapeutic strategies to convert nontoxic small molecules into toxic small-molecule chemo-drugs in the TME is still a huge challenge. To address this issue, herein we have developed a biomimetic dual-responsive bioengineered nanotheranostics system via the supramolecular co-assembly of the nontoxic small-molecule 1,5-dihydroxynaphthalene (DHN) and small-molecule photosensitizer indocyanine green (ICG) followed by surface cloaking through red blood cell membranes (RBCs) for intracellular cascade-synthesizing chemo-drugs and efficient oncotherapy. Such nanotheranostics with a suitable diameter, core-shell structure, ultrahigh dual-drug payload rate, and excellent stability can efficiently accumulate in tumor regions and then internalize into tumor cells. Under the dual stimulations of near-infrared laser irradiation and acidic lysosomes, the nanotheranostics system exhibited exceptional instability under heat-primed membrane rupture and pH decrease, thereby achieving rapid disassembly and on-demand drug release. Furthermore, the released ICG can efficiently convert 3O2 into 1O2. After that, the generated 1O2 can efficiently oxidize the released nontoxic DHN into the highly toxic chemo-drug juglone, thereby realizing intracellular cascade-synthesizing chemo-drugs and synergistic photodynamic-chemotherapy while reducing detrimental side effects on normal cells or tissues. Overall, it is envisioned that RBC-cloaked nanotheranostics with intracellular cascade-synthesizing chemo-drugs can provide a promising strategy for intracellular chemo-drug synthesis-based oncotherapy.

Water use strategies of Ferula bungeana on mega-dunes in the Badain Jaran Desert.

In desert ecosystems, ephemeral plants have developed specialized water use strategies in response to long-term natural water stress. To examine the water use strategies of desert ephemeral plants under natural extreme drought conditions, we investigated the water absorption sources, water potential, hydraulic conductivity, and water use efficiency of Ferula bungeana at different elevations on the slopes of mega-dunes in the Badain Jaran Desert, Inner Mongolia, during a period of extreme drought. We found that the water utilized by F. bungeana was mostly absorbed from the 0-60 cm soil layers (80.47 ± 4.28%). With progression of the growing season, the source of water changed from the 0-30 cm soil layer to the 30-60 cm layer. The water potentials of the leaves, stems, and roots of F. bungeana were found to be characterized by clear diurnal and monthly variation, which were restricted by water availability and the hydraulic conductivity of different parts of the plant. The root hydraulic conductivity of F. bungeana was found to be considerably greater than that of the canopy, both of which showed significant diurnal and monthly variation. The water use efficiency of F. bungeana under extreme drought conditions was relatively high, particularly during the early and late stages of the growing season. Variations in water availability led to the regulation of water uptake and an adjustment of internal water conduction, which modified plant water use efficiency. These observations tend to indicate that the water use strategies of F. bungeana are mainly associated with the growth stage of plants, whereas the distribution pattern of plants on mega-dunes appeared to have comparatively little influence. Our findings on the water use of ephemeral plants highlight the adaptive mechanisms of these plants in desert habitats and provide a theoretical basis for selecting plants suitable for the restoration and reconstruction of desert ecosystems.

Leaf chlorophyll parameters and photosynthetic characteristic variations with stand age in a typical desert species (Haloxylon ammodendron).

As a desert shrub, Haloxylon ammodendron combines ecological, economic, and social benefits and plays an important role in the ecological conservation of arid desert areas. Understanding its physiological characteristics and its mechanism of light energy utilization is important for the conservation and utilization of H. ammodendron. Therefore, we selected five stands (5-, 11-, 22-, 34-, and 46-year-old) of H. ammodendron as research objects in the study and measured their photosynthetic light response curves by a portable open photosynthesis system (Li-6400) with a red-blue light source (6400-02B). Then, we measured the leaf chlorophyll parameters in the laboratory, calculated the photosynthetic characteristics by using Ye Zipiao's photosynthetic model, analyzed their variation patterns across stand ages, and explored the relationships between leaf chlorophyll parameters and photosynthetic characteristics. The results showed that leaf chlorophyll parameters and photosynthetic characteristics of H. ammodendron at different stand ages were significantly different. Chl content, P nmax, and LUEmax of H. ammodendron were V-shaped with the increase of stand age. The 5-year-old H. ammodendron was in the rapid growth period, synthesized more Chl a+b content (8.47 mg g-1) only by using a narrower range of light, and the Pnmax and LUEmax were the highest with values of 36.21 µmol m-2 s-1 and 0.0344, respectively. For the 22-year-old H. ammodendron, due to environmental stress, the values of Chl a+b content, P nmax, and LUEmax were the smallest and were 2.64 mg g-1, 25.73 µmol m-2 s-1, and 0.0264, respectively. For the older H. ammodendron, its Chl content, P nmax, and LUEmax were not significantly different and tended to stabilize but were slightly higher than those of the middle-aged H. ammodendron. On the other hand, the other photosynthetic parameters did not show significant variation patterns with stand age, such as R d, AQE, LSP, LCP, and I L-sat. In addition, we found that the relationships between Chl a+b content and P nmax and between Chl a+b content and LUEmax were highly correlated, except for the older H. ammodendron. Thus, using leaf chlorophyll content as a proxy for photosynthetic capacity and light use efficiency should be considered with caution. This work will provide a scientific reference for the sustainable management of desert ecosystems and vegetation restoration in sandy areas.

The Process of Soil Desiccation under Haloxylon ammodendron Plantations: A Case Study of the Alxa Legue Desert, China.

Haloxylon ammodendron is a desert shrub widely used as a windbreak and for sand fixation, and it has achieved remarkable results in China. However, in desert areas, large-scale afforestation increases soil water consumption and forms a dried soil layer (DSL), the development of which seriously threatens the sustainable development of the ecosystem. In this study, soil moisture in the 0-400 cm soil profile was measured in selected 5-, 11-, 22-, 34-, and 46-year-old plantations of Haloxylon ammodendron plantations in Alxa Legue, China, and three soil desiccation evaluation indices were calculated-the soil desiccation index (SDI), DSL thickness (DSLT), and DSL soil water content (DSL-SWC)-to analyze the change pattern of the soil water content for different stand ages. The results showed that the shallow water layer (0-200 cm) was depleted sharply in the first five years of Haloxylon ammodendron plantation growth, but no DSL developed; the inflection point of soil water content change appeared after 10 years of growth, after which the shallow soil water was depleted and the drying process of the deep soil water content was significantly faster than that in the early growth period. The deep soil layer (200-400 cm) was depleted seriously after 22 years of afforestation, the soil drying phenomenon was obvious, and the DSL developed from the 172 cm soil layer. After 46 years of afforestation, the DSL was fully developed and the DSL-SWC was only 0.034 cm3 cm-3. Priority should thus be given to the use of less water-consuming shrub species; alternatively, after 5 years of growth of Haloxylon ammodendron plantations, certain water control measures should be taken to maintain the soil water balance.

Interface engineering for gain perovskite photodetectors with extremely high external quantum efficiency.

Efficient CH3NH3PbI3 photodetectors (PDs) with an extremely high gain of the maximum external quantum efficiency (EQE) of 140 000% within the ultraviolet region to the near infrared region (NIR) and an extremely high responsivity (R) under a low bias of -5 V were successfully fabricated. The fabricated devices manifested outstanding environmental stability with only 10% degradation of EQE after being exposed to air for 24 h. These obtained results indicate the promising potential of perovskite PDs for visible light communication applications.

High insulin concentrations repress insulin receptor gene expression in calf hepatocytes cultured in vitro.

The major role of insulin and the insulin receptor (InsR) in the liver is to mediate glucose uptake into hepatocytes to synthesize glycogen and to maintain blood glucose homeostasis. In this study, we investigated the effects of high insulin concentrations on InsR gene expression in calf hepatocytes cultured in vitro. After the cells were cultured for 72 h, insulin was added to the culture solution at final concentrations of 0, 1, 10, 100 or 1000 nM. InsR mRNA expression was determined by semi-quantitative RT-PCR. The results showed that InsR mRNA expression in hepatocytes, adjusted for ß-actin expression, decreased dose dependently with increasing insulin concentration. InsR mRNA expression was similar at 1 and 10 nM insulin, but was significantly lower than that in the control. InsR expression was similar at 100 and 1000 nM insulin, but was significantly lower than that in the control, 1 and 10 nM insulin groups. These data suggest that high concentrations of insulin significantly repress InsR mRNA expression in calf hepatocytes, and this inhibition occurs in a dose-dependent manner. Further studies are needed to investigate the mechanisms underlying these effects of insulin.